Dot printer and printing method

Abstract: A data control apparatus is structured to execute complementary recording on one pixel array by dividing the scans of a recording head into four. In a nozzle context memory, the nozzle context data, which can be updated, are stored as control data to determine discharge or non-discharge of ink from discharge ports. In an operational circuit, the nozzle context data and image data are processed operationally, thus outputting drive data for the recording head. The data that indicates ink discharge in one pixel array are sequentially assigned to recording data per scan appropriately by use of the nozzle context data and the operational circuit. With the structure thus arranged, it is possible to implement making the capacity of memory smaller for use of data to control recording or non-recording, and also, to execute an intermittent recording by controlling recording or non-recording as required.

Description: BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an ink jet recording apparatus that discharges ink liquid to a recording medium for the formation of images thereon, and an ink jet recording method therefor. Related Background Art There have been widely known recording apparatuses that adopt the ink jet method whereby to form images by discharging ink to an recording medium. The ink jet recording method is of a recording method of a non-impact type. Therefore, its noises are smaller. Also, this method has an advantage, among others, that color images can be recorded easier by use of multiple color ink. With such advantages this method has, it becomes more popular increasingly and rapidly in recent years. Also, for the ink jet method, the bubble jet method is known, in which electrothermal transducing elements (or heaters) that serve as means for discharging ink are used for the generation of air bubbles in ink by giving thermal energy generated by the electrothermal transducing elements to ink, and then, ink is discharged by the utilization of pressures exerted when air bubbles are generated. This bubble jet method makes it possible to arrange discharge ports in high density. Also, it has an advantage that apparatuses can be fabricated smaller, while performing image recording in higher resolution. For the recording head of an ink jet method, the so-called multiple nozzle head is generally used. For this head, a plurality of ink discharge ports are arranged to enable plural ink droplets to be discharged at a time by use of recording elements provided for the recording head. In accordance with a recording head of the kind where a plurality of ink discharge ports are arranged, it is possible to form a plurality of dots at a time, and also, to shorten a period of time required for recording characters, images, and the like, which are formed by the collection of such dots. The recording speed of the apparatus can be enhanced as a whole accordingly. However, it is known that there are the problems as given below with respect to recording by use of the multiple nozzle head described above. In other words, for a recording head of the kind, it is difficult to manufacture a plurality of ink discharge ports and recording elements uniformly. As a result, recorded dots become uneven to a certain extent inevitably. For the multiple nozzle head, the amount of ink droplets and the discharging direction thereof are varied minutely, for example, due to the variation in the configuration of ink discharge ports and some other factors. Also, for the recording elements that discharge ink, its discharging performance is caused to vary, producing adverse effect upon discharged ink droplets. Also, in the bubble jet method described above, it is obvious that difference in the thermal energy generated by each of the individual recording elements makes the discharged ink droplets uneven. As described above, unevenness occurs in the densities of recorded images if the sizes and densities of dots to be recorded are made uneven. Particularly, for a recording apparatus of a serial type where recording is made while the recording head travels, the density unevenness takes place in the scanning of the recording head itself, at first, and then, the patterns of uneven density are formed repeatedly by a specific cycle due to the repeated scanning. Such patterns repeatedly made in a specific cycle can easily be observed visually by eyesight. In such case, therefore, the quality of recorded images and the like becomes remarkably inferior. In order to reduce a density unevenness of the kind for the serial type recording apparatus, there has been proposed a method called a multiple scan where the feeding amount of a recording medium per scan of the recording head is made smaller than the recording width of the recording head, and an image in a given area is completed by the application of several scans. In accordance with this method, pixels on a given line in the scanning direction of the recording head are recorded by use of different discharge ports per scan. As a result, the density unevenness, which is characteristic of each discharge port of the ink jet head, is scattered in the recorded image, thus making its density unevenness less conspicuous. Also, the defective discharge may take place in a particular ink discharge port of a multiple nozzle head and causes the generation of density unevenness in a recorded image or the discharge amount may vary due to the difference in use frequency of the discharge ports of the head. If use frequencies may differ greatly between each of them, the discharge amount of each discharge port varies. As a result, the density unevenness occurs in the recording image. Also, if the defective discharge takes place in a discharge port whose use frequency is particularly high, a problem arises to present more conspicuous streaks and density unevenness. Moreover, if it is arranged to form an image by the frequent use of only specific ink discharge ports, the use frequencies of ink discharge ports are greatly deviated among them. As a result, the probability of malfunction becomes higher for the discharge port whose use frequency is high. In other words, a problem is encountered that the life of a recording head becomes shorter eventually. As means for solving these problems, a technique is disclosed in the specification of Japanese Patent Laid-Open Application No. 5-330083 wherein different discharge ports are used per pixel when forming pixels, and at the same time, the use frequencies of discharge ports are made uniform. In accordance with the disclosed technique, plural pixels contained in a given line in the main scanning direction are formed by the application of several scans, while a control is given so that plural pixels to be recorded are assigned to the corresponding discharge ports in a specific order per scan. In this way, the ink discharge ports are used uniformly, thus making it possible to prolong the life of the recording head. Also, even if defective discharge or other drawbacks take place in part of discharge ports, the location of pixels that are not formed due to the defective discharges is scattered to make such pixels less conspicuous. Now, the recording process will be described in accordance with such conventional method described above. Fig. 5A is a view which schematically shows an ink jet type recording head 1 provided with a plurality of ink discharge ports (hereinafter, simply referred to as discharge ports). In Fig. 5A, 128 discharge ports are arranged in the direction from the upper part to the down part of the recording head 1. Here, the numbers marked with # are those indicating the positions of the discharge ports. For the recording head 1, the discharge ports #1 to #128 are provided. Also, Fig. 5B is a view which illustrates the conventional recording method using the recording head 1. In Fig. 5B, an example is shown, in which an image is formed by scanning a given recording area with the recording head 1 four times. This example shows a recording method adopted for a so-called serial printer. The recording head 1 performs its recording while scanning in the main scanning direction indicated by a reference mark X, and the recording medium is fed in the sub-scanning direction indicated by a reference mark Y in Fig. 5B. This feeding of the recording medium is sufficient provided that the recording medium shifts relative to the recording head. For example, it may be possible to arrange for a recording head to move in the sub-scanning direction while a recording medium is fixed. For the example shown in Fig. 5B, it is arranged that the recording head 1 moves relatively with respect to the recording medium in order to describe the recording positions of the recording head 1 on the recording medium. Also, in Fig. 5B, reference numerals 1001, 1002, 1003, and 1004 designate the corresponding pixel arrays in the main scanning direction of the recording head 1, which are adjacent to each other in the arrangement direction of the discharge ports of the recording head 1, respectively. In Fig. 5B, the pixel array 1001 is formed by ink droplets discharged from the discharge port numbers #97, #65, #33, and #1, respectively, at each of the four-time scans of the head, for example. Fig. 6 is a view which illustrates an image formed on a recording sheet by the application of the recording method shown in Figs. 5A and 5B. Each square represents the position where one pixel is formed. The squares indicated by slanted lines represent pixels formed by discharged ink. In Fig. 6, reference numerals 1001 to 1004 designate those pixel arrays shown in Fig. 5B. The numbers 1 to 16 shown in the lower part of Fig. 6 are line numbers that indicate recording positions in the main scanning direction of the recording head 1. In Fig. 6, only pixels designated by the numbers 1 to 16 are described for convenience's sake. Figs. 7A, 7B, 7C, and 7D represent each of the images formed by each scanning when the image shown in Fig. 6 is formed by the four-time scans as shown in Fig. 5B. Each of them corresponds to each image formed at the time of first to fourth scans, respectively. In Figs. 7A, 7B, 7C and 7D, one square represents the position where one pixel is formed as in Fig. 6. The squares with slanted lines indicate pixels formed by discharged ink. The numbers with # shown on the righthand side of each figure designate the discharge port numbers that correspond to the pixel positions in each of the pixel array. Also, the numbers shown in the lower part of each figure correspond to the line numbers represented in Fig. 6, respectively. Fig. 8 is a view which illustrates the recorded pixels in the pixel array by use of the respective discharge ports per each scan in order to form them in such pixel array with attention given to the pixel array 1001 in the main scanning direction of the recording head 1. In Fig. 8, one square represents the position where one pixel is formed as in Fig. 6 and Fig. 7A, 7B, 7C and 7D. The squares with slanted lines represent the pixels to be recorded by discharged ink. Also, each number with # and the number shown in the lower part of Fig. 8 are the same as those shown in Fig. 6 and Figs. 7A, 7B, 7C and 7D. On referring to Fig. 8, it is understandable that the discharge port numbers #1, #33, #65, and #97 are used twice, respectively, in order to form the pixel array 1001. In this way, with the sequential use of the discharge ports, it becomes possible to almost uniformalize the use frequencies of plural discharge ports, thus making the life of the recording head longer. At the same time, the deterioration of the image quality caused by defective discharges can be reduced, because the positions where pixels are not recorded are scattered even if defective discharges take place; hence obtaining good images. However, in accordance with the conventional method described above, there is a need for the provision of drive data on discharge/non-discharge of ink per discharge port per scan using mask pattern or the like. In this case, a large memory capacity is needed depending on the numbers of recording scans to be executed. For example, when one pixel array is formed using different discharge ports of N numbers by recording it with N times of scans on a given recording area, it is required to increase the required memory capacity N times the capacity provided for recording such given recording area by one time scan only. In other words, the total amount of data to be stored on the memory should be calculated as follows: {(the numbers of discharge ports of a recording head) × (pixel numbers per one pixel array) × N} Such an increase of memory capacity creates a problem that the costs of an apparatus are inevitably increased as a whole. Now, among known recording modes made available to recording apparatuses, there is one used for a highspeed recording in order to confirm the recorded result of prints or the like. This is generally called a draft mode. The draft mode is often applied to the case where it takes a long time to output the result of a regular recording, for example, and where such record should be made immediately or the output is made only for a document which is not very important. The draft mode is generally a method in which the pixels to be recorded are thinned for recording. The thinned recording is implemented to make the recording speed faster. Among the thinned patterns, there is a checker pattern, for example. Also, for the draft mode, the numbers of dots to be recorded are smaller than those of regular output. Therefore, this mode is also adopted for the purpose of curtailing ink consumption. However, if an image is recorded in such draft mode while thinning the pixels to be recorded like a checker pattern, there is a fear that pixels are thinned in a way which tends to produce an image whose characters or the like cannot subsequently be recognized easily. DE-A-4127560 discloses an arrangement for recording a pattern in which each part of the recording medium is scanned twice during printing, and the data to be recorded is divided into data printed in the first scan and data printed in the second scan. EP-A-0595517 also discloses an arrangement in which each part of the recording medium is scanned twice with printing during each scan. It discloses an apparatus in which image data is stored in a frame memory. A controller executes assignment processing, according to a selected rule, which not only decides which ejection port is used to eject ink droplets for forming each dot but also decides which scan is used for ejecting the ink droplets. The results of the assignment processing are stored in a driving data RAM as driving data. During scanning, the driving data is sent to a head driver. SUMMARY OF THE INVENTION According to the present invention there is provided data generating apparatus as set out in claim 1, recording apparatus as set out in claim 13, a method of generating drive data as set out in claim 19, and a method of recording an image as set out in claim 30. Optional features are set out in the remaining claims. An embodiment of the present invention seeks to provide an ink jet recording apparatus capable of implementing the adoption of a smaller memory to store data for controlling discharge/non-discharge of ink from plural discharge ports, and also, capable of assigning pixels to be formed to plural discharge ports appropriately when images are recorded intermittently as in the case of the so-called draft mode or the like, and to provide an ink jet recording method therefore. Embodiments of the invention will now be described with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram which shows the structure of the principal part of a first embodiment in accordance with the present invention. Fig. 2 is a view which illustrates the stored contents of an output buffer represented in Fig. 1. Figs. 3A, 3B, 3C and 3D are views which illustrate the states of changes in the stored contents of the nozzle context memory represented in Fig. 1. Fig. 4 is a view which partly shows the structure of an operational circuit represented in Fig. 1. Figs. 5A and 5B are views which illustrate recording methods for recording separately by means of four-time scans. Fig. 6 is a view which shows one example of a recorded image. Figs. 7A, 7B, 7C and 7D are views which illustrate record images per scans when the image is recorded by separating it into four-time scans. Fig. 8 is a view which illustrates discharge ports to be used for one pixel array in Figs. 7A. 7B, 7C and 7D. Figs. 9A and 9B are views which illustrate recording methods in accordance with a second embodiment of the present invention. Figs. 10A and 10B are views which illustrate the stored contents of the nozzle context memory in accordance with the second embodiment of the present invention. Figs. 11A and 11B are views which illustrate recorded images per scan when the image shown in Fig. 6 is recorded by dividing it into two-time scans in accordance with the second embodiment of the present invention. Fig. 12 is a view which partly shows the structure of an operational circuit in accordance with the second embodiment of the present invention. Fig. 13 is a view which illustrates the discharge ports to be used for one pixel array shown in Figs. 11A and 11B. Figs. 14A, 14B, 14C and 14D are views which illustrate the processed contents of the operational circuit in accordance with the first embodiment of the present invention. Figs. 15A and 15B are views which illustrate the processed contents of the operational circuit in accordance with the second embodiment of the present invention. Fig. 16 is a perspective view which shows the principal part of an ink jet printing apparatus to which the present invention is applicable. Fig. 17 is a block diagram which shows the principal part of a fourth embodiment in accordance with the present invention. Fig. 18 is a view which illustrates changes in the stored contents of the nozzle context memory shown in Fig. 17. Fig. 19 is a view which shows one example of an image recorded by the recording head represented in Fig. 17. Fig. 20 is a block diagram which shows the principal part of a fifth embodiment in accordance with the present invention. Figs. 21A, 21B, 21C and 21D are views which partly show the structures of the operational circuit represented in Fig. 20. Figs. 22A and 22B are views which partly show the structures of an operational circuit in accordance with a sixth embodiment of the present invention. Fig. 23 is a block diagram which schematically shows the structure when the printing apparatus of the present invention is adopted for an information processing apparatus provided with the functions of a word processor, a personal computer, a facsimile equipment, and a copying apparatus. Fig. 24 is a schematic view which shows the outer appearance of the information processing apparatus represented in Fig. 23. Fig. 25 is a view which schematically shows one example where the printing apparatus of the present invention is adopted for an information processing apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, with reference to the accompanying drawings, the preferred embodiments of the present invention will be described in detail. (First Embodiment) As a recording method, the present embodiment is arranged so that it adopts the recording method that divides scanning into four times in the same manner as described in conjunction with Figs. 5A and 5B. Also, as its image recording example, the present embodiment records an image as described in conjunction with Fig. 6. Fig. 1 is a structural block diagram which shows the principal part of a printing apparatus as the first embodiment in accordance with the present invention. In Fig. 1, a reference numeral 1 designates a recording head, which is provided with 128 discharge ports; 101, a main controller; 102 an output buffer that stores binary data corresponding to dots to be recorded, and the output of the output buffer 102 is a one-bit information, which indicates ink discharge with the output "1", and non-discharge with the output "0"; 103, a counter that indicates the line numbers in the scanning direction of the recording head 1; 104, a counter that indicates the discharge port numbers; 105, a memory that stores control data in respect of each of the discharge ports, which assign pixels to be formed to respective ones of the plurality of discharge ports (i.e. assign each pixel to a respective scan). The control data is provided for each of the discharge ports, and formed with 2-bit data for one discharge port, and is capable of obtaining four states of "0", "1", "2", and "3" (hereinafter, this control data is referred to as a context data or a nozzle context, and 105 is referred to as a nozzle context memory). A reference numeral 106 designates an operational circuit, and as described later, it works out head drive data DO and new nozzle context SO for the next line (print column) using data DI from the output buffer 102, data SI for the current line from the nozzle context memory 105, and the discharge port numbers. A reference numeral 107 designates a head driver controller that supplies the output from the operational circuit 106 to the driver 108 for the recording head 1 in response to the control signals from the main controller 101. Here, the main controller 101 gives increment at first to the port counter 104 to let the counter indicate the discharge port numbers sequentially beginning at No. 1. Then, after this counter indicates the discharge port number 128, the main controller gives increment to the line counter 103, which indicates the line numbers in the scanning direction. Fig. 2 is a view which shows one example of the stored contents of the output buffer 102. For the present embodiment, the description will be made using the data that correspond to the image represented in Fig. 6. In other words, one square corresponds to one pixel in Fig. 2, and of the squares, the square given "1" indicates that the corresponding pixel is formed by discharged ink. Also, the square given "0" indicates the position where no ink discharge is provided, thus forming no pixel. In Fig. 2, reference numerals 1001, 1002, 1003, and 1004 designate pixel arrays in the scanning direction of the head 1, respectively. Also, reference numerals 1 to 16 designates the line numbers in the scanning direction of the head 1. For the present embodiment, the description will be made of the lines from 1 to 16 only for convenience' sake. Figs. 3A, 3B, 3C, and 3D are views schematically showing the successive contents of the nozzle context memory 105 as the line number increments, during the first, second, third, and fourth scans, respectively, as shown in Fig. 58. In Fig. 3A, reference numerals 1001, 1002, 1003, and 1004 designate pixel arrays formed by pixels in the scanning direction of the head 1, respectively. These arrays correspond to those shown in Fig. 2. Reference numerals 1 to 16 are also the same, which designate the line numbers in the scanning direction of the head. In this example, the nozzle context numbers in Fig. 3A are related to the pixel arrays 1001, 1002, 1003, and 1004 at the time of the first scan. The control data (context data) for these pixel arrays are 0, 0, 0, and 0 before line number is recorded, and then, the data are rewritten to be 1, 0, 1, 1 by means of the operational circuit 106 before recording line number 2. Figs. 14A to 14D are truth tables which illustrate the outputs of the operational circuit 106 for all possible inputs. In Fig. 14D, a reference sign DI designates an input from the output buffer 102; DO, an output to the head driver controller 107; SI, an input from the nozzle context memory 105; and SO, an output to the nozzle context memory 105. Also, the input DI from the output buffer 102, and the output DO to the head driver controller 107 are one-bit information, respectively, and "1" indicates ink discharge, and "0" indicates non-discharge of ink. The output DO becomes the drive data to drive the head. Also, the input and output SI and SO with respect to the nozzle context memory 105 are two-bit information, and as described above, these can be in the four different states of 0, 1, 2, and 3. For the present embodiment, the recording head 1 is provided with 128 discharge ports in total. As shown in Fig. 5B, these ports are divided into four groups of 32 discharge ports each in order to complete an image in a given area by the application of four-time scans. The recording sheet is fed by an amount equivalent to the portion of 32 discharge ports per recording scan. The operational circuit 106 makes the contents of process different with respect to the discharge ports of each of the divided groups. In accordance with the present embodiment, the discharge ports are divided into four groups. Therefore, processes are made different for every 32 discharge ports as shown in Figs. 14A to 14D. For the discharge ports numbers 1 to 32, the process is executed as shown in Fig. 14A; for 33 to 64, as shown in Fig. 14B; 65 to 96, as shown in Fig. 14C; and 97 to 128, as shown in Fig. 14D, respectively. Fig. 4 is a view which shows one example of the circuit, which is structured in the operational circuit 106, in order to implement the process described in conjunction with Figs. 14A to 14D. In Fig. 4, a reference numeral 111 designates an adder to add the output DI from the output buffer 102 and the output SI from the nozzle context memory 105; 112, a decoder that develops the two-bit information of the output SI from the nozzle context memory 105 to the four-bit information; 113, a selector that selects the outputs from the decoder 112 in accordance with the discharge port numbers; and 114, an AND circuit (logical product). Here, the adder 111 adds one-bit DI and two-bit SI (obtaining value 0, 1, 2, and 3), and then, outputs two-bit SO (obtaining value 0, 1, 2, and 3). Also, when SI = 3, DI = 1, that is, when the adder 111 receives B1 = "1", B2 = "1", A0 = "1", the added value overflows, making the output SO = 0, that is, the outputs C0 and C1 from the adder become "0". The decoder 112 makes Y0 = Y1 = Y2 = Y3 = "0" when the input SI = 0, that is, when the decoder 112 receives A = "0", B = "0". Also, it makes Y1 = 1, Y0 = Y2 = Y3 = "0" when SI = 1; Y2 = "1", Y0 = Y1 = Y3 = "0" when SI = 2; and Y3 = 1, Y0 = Y1 = Y2 = 0 when SI = 3. The selector 113 outputs the input A to Y when the nozzle number are 97 to 128; the input B to Y when the nozzle numbers are 65 to 96; the input C to Y when the nozzle number 33 to 64; and the input D to Y when the nozzle numbers are 1 to 32. Therefore, if, for example, SI = 3, DI = 1, and the nozzle number 1, the outputs C0 and C1 from the adder 111 become "0", that is, SO = 0. At the same time, the decoder 112 makes Y = 1, and since the selector 113 selects the input D, the output Y from the selector 113 becomes "1", thus making the output DO of the circuit 114 "1". A. [Outline of the Operation] Now, with reference to Fig. 1, the outline of the operation will be described. At first, the main controller 101 clears the contents of the nozzle context memory 105 to set the context data at "0" for all the discharge ports. Also, it instructs the line counter 103 to set the line number to 1, while instructing the port counter 104 to set the discharge port number to 1. In this way, the output buffer 102 outputs data DI corresponding to the line number 1 and the discharge port number 1. Also, the nozzle context memory 105 outputs context data SI corresponding to the discharge port number 1. The operational circuit 106 executes operation in accordance with the outputs from the output buffer 102, nozzle context memory 105, and the port counter 104, and outputs the head drive data DO for the discharge port number 1, and the data SO of the new nozzle context, to be used for discharge port number 1 on line number 2. The nozzle context memory 105 rewrites the context data stored for discharge port number 1 with the new nozzle context data SO output from the operational circuit 106. The head driver controller 107 controls the head driver 108 in accordance with the head drive data DO on the discharge port number 1 output from the operational circuit 106, thus controlling discharge or non-discharge of ink from the discharge port #1 of the recording head 1. Then, the main controller 101 instructs the port counter 104 to increase its value by 1. Thus, the output buffer 102 outputs the data DI that corresponds to the line number 1 and the discharge port number 2. Also, the nozzle context memory 105 outputs the nozzle context data DI that corresponds to the discharge port number 2. The operational circuit 106 executes operation in accordance with the outputs from the output buffer 102, nozzle context memory 105, and the port counter 104, and outputs the drive data DO for the discharge port number 2, and the data SO of the new nozzle context, to be used for discharge port number 2 on line number 2. The nozzle context memory 105 rewrites the context data stored for discharge port number 2 with the new nozzle context data SO output from the operational circuit 106. The head driver controller 107 controls the head driver 108 in accordance with the head drive data DO on the discharge port number 2 output from the operational circuit 106, and controls the discharge or non-discharge of ink from the discharge port #2 of the recording head 1. Thereafter, the same processes will be executed up to the discharge port number 128 of the line number 1. Then, when the processes required for the line number 1 are completed for all the discharge ports, the processes for the next line number will be executed. The main controller 101 instructs the line counter 103 to increase its counter value by 1 so that the line number 2 is indicated. Also, it instructs the port counter 104 so that the discharge port number 1 is indicated. Thus, the output buffer 102 outputs the data DI on the line number 2 and the discharge port number 1. Also, the nozzle context memory 105 outputs the data SI on the discharge port number 1. The operational circuit 106 executes operation in accordance with the outputs from the output buffer 102, nozzle context memory 105, and the port counter 104, and outputs the drive data DO for the discharge port number 1, and the data SO of the new nozzle context, to be used for discharge port number 1 on line number 3. The nozzle context memory 105 rewrites the context data stored for discharge port number 1 with the new nozzle context data SO output from the operational circuit 106. The head driver controller 107 controls the head driver 108 in accordance with the head drive data DO on the discharge port number 1 output from the operational circuit 106, and controls the discharge or non-discharge of ink from the discharge port #1 of the recording head 1. Thereafter, the same processes will be executed in the same manner for all the discharge port numbers of all the line numbers in the same manner, hence forming an image. The operation described above is executed in the same manner each at the first, second, third, and fourth scans as shown in Figs. 5A and 5B. Before each of the scans is executed, the contents of the nozzle context memory are cleared by means of the main controller 101, thus setting all the contexts of the discharge ports at "0". Also, in the above description, it has been described that the head driver 108 is controlled at each time the operational process is completed for each of the discharge ports, thus executing the discharge operation. However, the present invention is not necessarily limited to such recording control. There is no problem even if the structure is arranged to provide a memory for storing the discharge data on all the discharge ports, in which the outputs DO from the operational circuit 106 are stored for all the discharge port portions, and then, the recording control is made at the drive timing in accordance with the conventionally known recording method, such as a time division drive, on the basis of the stored discharge data in the memory thus provided. Also, it may be possible to arrange a structure so that a shift register is provided for all the bits corresponding to all the discharge ports in the recording head 1 in order to store the discharge data. B. [Specific Example of the Operation] Now, with reference to Fig. 2, Figs. 3A to 3D, Figs. 5A and 5B, and Fig. 6, the specific description will be made of processes, in particular, for the pixel lines 1001, 1002, 1003, and 1004 by separating them for the first, second, third, and fourth scans, respectively. B-1. [First Scan] (Line Process for the Line Number 1) The line counter 103 indicates the line number 1. The port counter 104 indicates the discharge port numbers 1, 2, 3, etc. sequentially for processing. Now, it is assumed that the discharge port number 97 is indicated for the pixel array 1001. As shown in Fig. 5B, the discharge port number 97 is the one that corresponds to the position of the pixel array 1001 at the time of first scan. The data DI from the output buffer 102 that corresponds to the line number 1 of the pixel array 1001 is "1" as shown in Fig. 2, while the context data SI on the discharge port number 97 in the context memory 105 corresponding thereto is "0" as shown in Fig. 3A at line number 1. Also, now that the discharge port number is 97, the input and output relationship provided by the operational circuit 106 corresponds to those shown in Fig. 14D. Therefore, the operational circuit 106 outputs "1" as the nozzle context data SO and the head drive data DO. Thus, the context of the discharge port number 97 in the nozzle context memory 105 is rewritten to "1", as shown in Fig. 3A at line number 2. Now, as shown in Fig. 5B, the port counter 104 indicates the discharge port number 98 corresponding to the pixel array 1002 at the time of first scan. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1002, is "0", while referring to Fig. 3A, the context data on the discharge port number 98 in the nozzle context memory 105 corresponding thereto is "0" when line number 1 is processed. Therefore, as shown in Fig. 14D, the operational circuit 106 outputs "0" as the nozzle context data SO and the head drive data DO. In this way, the context of the discharge port number 98 in the nozzle context memory 105 is rewritten to "0'', as shown in Fig. 3A at line number 2. Now, as shown in Fig. 5B, the port counter 104 indicates the discharge port number 99 corresponding to the pixel array 1003 at the time of first scan. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1003, is "1", while referring to Fig. 3A, the context data on the discharge port number 99 in the nozzle context memory 105 corresponding thereto is "0" when line number 1 is processed. Therefore, due to the input and output relationship shown in Fig. 14D, the operational circuit 106 outputs "1" as the nozzle context data SO and the head drive data DO. In this way, the context of the discharge port number 99 in the nozzle context memory 105 is rewritten to "1", as shown in Fig. 3A at line number 2. Now, as shown in Fig. 5B, the port counter 104 indicates the discharge port number 100 corresponding to the pixel array 1004 at the time of first scan. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1004, is "1", while referring to Fig. 3A, the context data on the discharge port number 100 in the nozzle context memory 105 corresponding thereto is "0" when line number 1 is processed. Therefore, it is noticeable that due to the input and output relationship shown in Fig. 14D, the operational circuit 106 outputs "1" as the nozzle context data SO and the head drive data DO. In this way, the context of the discharge port number 100 in the nozzle context memory 105 is rewritten to "1", as shown in Fig. 3A at line number 2. When the processes are completed up to the discharge port number 128 with respect to the line number 1 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 97, 98, 99, and 100 to "1", "0", "1", and "1", respectively, as indicated by the line number 2 shown in Fig. 3A. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 1, 0, 1, 1 of the line number 1 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 7A, respectively. (Line Process for the Line Number 2) After the line process described above for the line number 1, it proceeds to processing the line number 2. In this process, the line counter 103 indicates the next line number 2. As in the previous process, the port counter 104 is increased to 1, 2, 3, etc. sequentially for processing. Hereinafter, the description will be made of the processes for the discharge port numbers 97 to 100 corresponding to the pixel arrays 1001 to 1004. The data DI from the output buffer 102 that corresponds to the line number 2 of the pixel array 1001 is "1" as shown in Fig. 2, while the context data SI on the discharge port number 97 of the context memory 105 corresponding thereto is "1" as shown in Fig. 3A at line number 2. Therefore, due to the input and output relationship shown in Fig. 14D, the operational circuit 106 makes the data SO "2", and rewrites the context of the discharge port number 97 in the nozzle context memory to "2", as shown in Fig. 3A at line number 3, and also, the head drive data DO to "0". Now, the port counter 104 indicates the discharge port number 98 corresponding to the pixel array 1002. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 2 of the pixel array 1002, is "1", while, referring to Fig. 3A, the context data SI on the discharge port number 98 in the nozzle context memory 105 corresponding thereto is "0" when line number 2 is processed. Therefore, due to the input and output relationship shown in Fig. 14D, the operational circuit 106 makes the data SO "1", and rewrites the context of the discharge port number 98 in the nozzle context memory 105 to "1", as shown in Fig. 3A at line number 3, and also, the head drive data DO to "1". Now, the port counter 104 indicates the discharge port number 99 corresponding to the pixel array 1003. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 2 of the pixel array 1003, is "1", while referring to Fig. 3A, the context data on the discharge port number 99 in the nozzle context memory 105 corresponding thereto is "1" when line number 2 is processed. Therefore, due to the input and output relationship shown in Fig. 14D, the operational circuit 106 makes the data SO "2", and rewrites the context of the discharge port number 99 in the nozzle context memory to "2", as shown in Fig. 3A at line number 3, and also, the head drive data DO to "0". Now, the port counter 104 that indicates the discharge port number 100 corresponding to the pixel array 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 2 of the pixel array 1004, is "0", while referring to Fig. 3A, the context data on the discharge port number 100 in the nozzle context memory 105 corresponding thereto is "1" when line number 2 is processed. Therefore, due to the input and output relationship shown in Fig. 14D, the operational circuit 106 makes the data SO "1", and rewrites the context of the discharge port number 100 in the nozzle context memory 105 to "1", as shown in Fig. 3A at line number 3, and also, the head drive data DO to "0". When the processes are completed up to the discharge port number 128 with respect to the line number 2 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 97, 98, 99, and 100 to "2", "1", "2", and "1", respectively, as indicated by the line number 3 in Fig. 3A. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 0, 1, 0, 0 of the line number 2 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 7A, respectively. (Line Process for the Line Number 3) After the line process described above for the line number 2, it proceeds to processing the next line. In the next process, the counter line 103 is increased to indicate the line number 3. As in the previous process, the port counter 104 is increased to 1, 2, 3, etc. sequentially for processing. Now, hereinafter, the description will be made of the processes regarding the discharge port numbers 97 to 100 corresponding to the pixel arrays 1001 to 1004. The data DI from the output buffer 102 that corresponds to the line number 3 of the pixel array 1001 is "1" as shown in Fig. 2, while the context data SI on the discharge port number 97 of the context memory 105 corresponding thereto is "2" as shown in Fig. 3A at line number 3. Therefore, the operational circuit 106 makes the data SO "3", and rewrites the context of the discharge port number 97 in the nozzle context memory to ''3", as shown in Fig. 3A at line number 4, and also, the head drive data DO to "0". Now, the port counter 104 indicates the discharge port number 98 corresponding to the pixel array 1002. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 3 of the pixel array 1002, is "1", while, referring to Fig. 3A, the context data SI on the discharge port number 98 in the nozzle context memory 105 corresponding thereto is "1" when line number 3 is processed. Therefore, the operational circuit 106 makes the data SO "2", and rewrites the context of the discharge port number 98 in the nozzle context memory 105 to "2", as shown in Fig. 3A at line number 4, and also, the head drive data DO to "0". Now, the port counter 104 indicates the discharge port number 99 corresponding to the pixel array 1003. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 3 of the pixel array 1003, is "1", while referring to Fig. 3A, the context data on the discharge port number 99 in the nozzle context memory 105 corresponding thereto is ''2'' when line number 3 is processed. Therefore, the operational circuit 106 makes the data SO "3", and rewrites the context of the discharge port number 99 in the nozzle context memory to "3", as shown in Fig. 3A at line number 4, and also, the head drive data DO to "0". Now, the port counter 104 indicates the discharge port number 100 corresponding to the pixel array 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 3 of the pixel array 1004, is "0", while referring to Fig. 3A, the context data on the discharge port number 100 in the nozzle context memory 105 corresponding thereto is "1" when line number 3 is processed. Therefore, the operational circuit 106 makes the data SO "1", and rewrites the context of the discharge port number 100 in the nozzle context memory 105 to "1", as shown in Fig. 3A at line number 4, and also, the head drive data DO to "0". When the processes are completed up to the discharge port number 128 with respect to the line number 3 in the manner as described above, the nozzle context memory 105 is has rewritten the contexts of the discharge port numbers 97, 98, 99, and 100 to "3", "2", "3", and "1", respectively, as indicated by the line number 4 in Fig. 3A. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 0, 0, 0, 0 of the line number 3 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 7A, respectively. (Line Process for the Line Number 4) After the line process described above for the line number 3, it proceeds to processing the next line. In the next process, the line counter 103 is increased so as to indicate the next line number 4. As in the previous process, the port counter 104 is increased to 1, 2, 3, etc. sequentially for processing. Now, hereinafter, the description will be made of the processes regarding the discharge port numbers 97 to 100 corresponding to the pixel arrays 1001 to 1004. The data DI from the output buffer 102 that corresponds to the line number 4 of the pixel array 1001 is "1" as described shown in Fig. 2, while the context data SI on the discharge port number 97 of the context memory 105 corresponding thereto is "3" as shown in Fig. 3A at line number 4. Therefore, the operational circuit 106 makes the data SO "0", and rewrites the context of the discharge port number 97 in the nozzle context memory to "0", as shown in Fig. 3A at line number 5, and also, the head drive data DO to "0". Now, the port counter 104 indicates the discharge port number 98 corresponding to the pixel array 1002. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 4 of the pixel array 1002, is "1", while, referring to Fig. 3A, the context data SI on the discharge port number 98 in the nozzle context memory 105 corresponding thereto is "2" when line number 4 is processed. Therefore, the operational circuit 106 makes the data SO "3", and rewrites the context of the discharge port number 98 in the nozzle context memory 105 to "3", as shown in Fig. 3A at line number 5, and also, the head drive data DO to "0". Now, the port counter 104 indicates the discharge port number 99 corresponding to the pixel array 1003. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 4 of the pixel array 1003, is "1", while referring to Fig. 3A, the context data on the discharge port number 99 in the nozzle context memory 105 corresponding thereto is "3" when line number 4 is processed. Therefore, the operational circuit 106 makes the data SO "0", and rewrites the context of the discharge port number 99 in the nozzle context memory 105 to "0", as shown in Fig. 3A at line number 5, and also, the head drive data DO to "0". Now, the port counter 104 indicates the discharge port number 100 corresponding to the pixel array 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 4 of the pixel array 1004, is "0", while referring to Fig. 3A, the context data on the discharge port number 100 in the nozzle context memory 105 corresponding thereto is "1" when line number 4 is processed. Therefore, the operational circuit 106 makes the data SO "1", and rewrites the context of the discharge port number 100 in the nozzle context memory 105 to "1", as shown in Fig. 3A at line number 5, and also, the head drive data DO to "0". When the processes are completed up to the discharge port number 128 with respect to the line number 4 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 97, 98, 99, and 100 to "0", "3", "0", and "1", respectively, as indicated by the line number 5 in Fig. 3A. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 0, 0, 0, 0 of the line number 4 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 7A, respectively. Thereafter, the processes will be executed in the same manner for the first scan with respect to the line numbers 5 , 6, 7, etc. up to the last line. B-2. [Second Scan] The description will be made of the processes at the time of second scan. For the second scan, the recording positions are displaced from those for the first scan as shown in Fig. 5B. The pixel arrays 1001 to 1004 now correspond to the discharge port numbers 65 to 68 of the recording head 1. (Line Process for the Line Number 1) For recording of the line number 1, the line counter 103 indicates the line number 1, while the port counter 104 indicates the numbers from 1, 2, 3, etc. sequentially for processing. For the second scan, the pixel array 1001 is recorded by use of the discharge port number 65. Now, hereinafter, the description will be made of the processes corresponding to the pixel arrays 1001 to 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1001, is "1", while referring to Fig. 3B the context data SO on the discharge port number 65 in the nozzle context memory 105 corresponding thereto is "0" when line number 1 is processed. Also, the input and output for the processes of the operational circuit 106, which correspond to the discharge port numbers 65 to 68, are those shown in Fig. 14C. Therefore, the operational circuit 106 outputs "1" as the nozzle context data SO, and also, outputs "0" as the head drive data DO. In this way, the context of the discharge port number 65 in the nozzle context memory 105 is rewritten to "1", as shown in Fig. 3B at line number 2. Now, the port counter 104 indicates the discharge port number 66 assigned to the pixel array 1002 as shown in Fig. 5B. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1001, is "0", while referring to Fig. 3B, the context data on the discharge port number 66 in the nozzle context memory 105 corresponding thereto is "0" when line number 1 is processed. Therefore, due to the input and output relationship shown in Fig. 14C the operational circuit 106 outputs "0" as the nozzle context data SO and the head drive data DO. In this way, the context of the discharge port number 66 in the nozzle context memory 105 is rewritten to "0 ", as shown in Fig. 3B at line number 2. Now, as shown in Fig. 5B, the port counter 104 indicates the discharge port number 67 corresponding to the pixel array 1003 at the time of second scan. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1003, is "1", while, referring to Fig. 3B, the context data on the discharge port number 67 in the nozzle context memory 105 corresponding thereto is "0" when line number 1 is processed. Therefore, due to the input and output relationship shown in Fig. 14C, the operational circuit 106 outputs "1" as the nozzle context data SO and "0"-as the head drive data DO. In this way, the context of the discharge port number 67 in the nozzle context memory 105 is rewritten to "1", as shown in Fig. 3B at line number 2. Now, as shown in Fig. 5B, the port counter 104 indicates the discharge port number 68 corresponding to the pixel array 1004 at the time of second scan. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1004, is "1", while referring to Fig. 3B, the context data on the discharge port number 68 in the nozzle context memory 105 corresponding thereto is "0" when line number 1 is processed. Therefore, due to the input and output relationship shown in Fig. 14C, the operational circuit 106 outputs "1" as the nozzle context data SO and "0" as the head drive data DO. In this way, the context of the discharge port number 68 in the nozzle context memory 105 is rewritten to "1", as shown in Fig. 3B at line number 2. When the processes are completed up to the discharge port number 128 with respect to the line number 1 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 65, 66, 67, and 68 to "1", "0", "1", and "1", respectively, as indicated by the line number 2 shown in Fig. 3B. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 0, 0, 0, 0 of the line number 1 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 7B, respectively. (Line Process for the Line Number 2) After the line process described above for the line number 1, the line counter 103 indicates the next line number 2. The port counter 104 is increased to 1, 2, 3, etc. sequentially for processing. Hereinafter, the description will be made of the processes for the discharge port numbers 65 to 68 corresponding to the pixel arrays 1001 to 1004. The data DI from the output buffer 102 that corresponds to the line number 2 of the pixel array 1001 is "1" as shown in Fig. 2, while the context data SI on the discharge port number 65 of the context memory 105 corresponding thereto is "1" as shown in Fig. 3B at line number 2. Therefore, due to the input and output relationship shown in Fig. 14C, the operational circuit 106 makes the data SO "2", and rewrites the context of the discharge port number 65 in the nozzle context memory to "2", as shown in Fig. 3B at line number 3, and also, the head drive data DO to "0". Now, the port counter 104 indicates the discharge port number 66 corresponding to the pixel array 1002. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 2 of the pixel array 1002, is "1", while, referring to Fig. 3B, the context data SI on the discharge port number 66 in the nozzle context memory 105 corresponding thereto is "0" when line number 2 is processed. Therefore, due to the input and output relationship shown in Fig. 14C, the operational circuit 106 makes the data SO "1", and rewrites the context of the discharge port number 66 in the nozzle context memory 105 to "1", as shown in Fig. 3B at line number 3, and also, the head drive data DO to "0". Now, the port counter 104 indicates the discharge port number 67 corresponding to the pixel array 1003. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 2 of the pixel array 1003, is "1", while referring to Fig. 3B, the context data on the discharge port number 67 in the nozzle context memory 105 corresponding thereto is "1" when line number 2 is processed. Therefore, due to the input and output relationship shown in Fig. 14C, the operational circuit 106 makes the data SO "2", and rewrites the context of the discharge port number 67 in the nozzle context memory to "2", as shown in Fig. 3B at line number 3, and also, the head drive data DO to "1". Now, the port counter 104 indicates the discharge port number 68 corresponding to the pixel array 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 2 of the pixel array 1004, is "0", while referring to Fig. 3B, the context data on the discharge port number 68 in the nozzle context memory 105 corresponding thereto is "1" when line number 2 is processed. Therefore, due to the input and output relationship shown in Fig. 14C, the operational circuit 106 makes the data SO "1", and rewrites the context of the discharge port number 68 in the nozzle context memory 105 to "1", as shown in Fig. 3B at line number 3, and also, the head drive data DO to "0". When the processes are completed for all the discharge port numbers with respect to the line number 2 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 65, 66, 67, 68 to "2", "1", "2", and "1", respectively, as indicated by the line number 3 in Fig. 3B. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 1, 0 ,1, 0 of the line number 2 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 7B, respectively. (Line Process for the Line Number 3) After the line process described above for the line number 2, the line counter 103 is increased to indicate the next line number 3. The port counter 104 is increased to 1, 2, 3, etc. sequentially for processing. Now, hereinafter, the description will be made of the processes for the discharge port numbers 65 to 68 corresponding to the pixel arrays 1001 to 1004. The data DI from the output buffer 102 that corresponds to the line number 3 of the pixel array 1001 is "1" as shown in Fig. 2, while the context data SI on the discharge port number 65 of the context memory 105 corresponding thereto is "2" as shown in Fig. 3B at line number 3. Therefore, the operational circuit 106 makes the data SO "3", and rewrites the context of the discharge port number 65 in the nozzle context memory to "3", as shown in Fig. 3B at line number 4, and also, the head drive data DO to "0". Now, the port counter 104 indicates the discharge port number 66 corresponding to the pixel array 1002. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 3 of the pixel array 1002, is "1", while, referring to Fig. 3B, the context data on the discharge port number 66 in the nozzle context memory 105 corresponding thereto is "1" when line number 3 is processed. Therefore, the operational circuit 106 makes the data SO "2", and rewrites the context of the discharge port number 66 in the nozzle context memory 105 to "2", as shown in Fig. 3B at line number 4, and also, the head drive data DO to "1". Now, the port counter 104 that indicates the discharge port number 67 corresponding to the pixel array 1003. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 3 of the pixel array 1003, is "1", while referring to Fig. 3B, the context data on the discharge port number 67 in the nozzle context memory 105 is "2" when line number 3 is processed. Therefore, the operational circuit 106 makes the data SO "3", and rewrites the context data on the discharge port number 67 in the nozzle context memory to "3", as shown in Fig. 3B at line number 4, and also, the head drive data DO to "0". Now, the port counter 104 indicates the discharge port number 68 corresponding to the pixel array 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 3 of the pixel array 1004, is "0", while referring to Fig. 3B, the context data on the discharge port number 68 in the nozzle context memory 105 corresponding thereto is "1" when line number 3 is processed. Therefore, the operational circuit 106 makes the data SO "1", and rewrites the context data on the discharge port number 68 in the nozzle context memory 105 to "1", as shown in Fig. 3B at line number 4, and also, the head drive data DO to "0". When the processes are completed up to the discharge port number 128 with respect to the line number 3 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 65, 66, 67, and 68 to "3", "2", "3", and "1", respectively, as indicated by the line number 4 in Fig. 3B. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 0, 1, 0, 0 of the line number 3 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 7B, respectively. (Line Process for the Line Number 4) After the line process described above for the line number 3, the line counter 103 is increased to indicate the next line number 4. Also, the port counter 104 is increased to 1, 2, 3, etc. sequentially for processing. Now, hereinafter, the description will be made of the processes for the discharge port numbers 65 to 68 corresponding to the pixel arrays 1001 to 1004. The data DI from the output buffer 102 that corresponds to the line number 4 of the pixel array 1001 is "1" as shown in Fig. 2, while the context data SI on the discharge port number 65 of the context memory 105 corresponding thereto is "3" as shown in Fig. 3B at line number 4. Therefore, the operational circuit 106 makes the data SO "0", and rewrites the context data on the discharge port number 65 in the nozzle context memory to "0", as shown in Fig. 3B at line number 5, and also, the head drive data DO to "0". Now, the port counter 104 indicates the discharge port number 66 corresponding to the pixel array 1002. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 4 of the pixel array 1002, is "1", while, referring to Fig. 3B, the context data SI on the discharge port number 66 in the nozzle context memory 105 corresponding thereto is "2" when line number 4 is processed. Therefore, the operational circuit 106 makes the data SO "3", and rewrites the context data on the discharge port number 66 in the nozzle context memory 105 to ''3", as shown in Fig. 3B at line number 5, and also, the head drive data DO to "0". Now, the port counter 104 indicates the discharge port number 67 corresponding to the pixel array 1003. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 4 of the pixel array 1003, is "1", while referring to Fig. 3B, the context data SI on the discharge port number 67 in the nozzle context memory 105 corresponding thereto is "3" when line number 4 is processed. Therefore, the operational circuit 106 makes the data SO "0", and rewrites the context data on the discharge port number 67 in the nozzle context memory to "0", as shown in Fig. 3B at line number 5, and also, the head drive data DO to "0". Now, the port counter 104 indicates the discharge port number 68 corresponding to the pixel array 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 4 of the pixel array 1004, is "0", while referring to Fig. 3B, the context data on the discharge port number 68 in the nozzle context memory 105 corresponding thereto is "1" when line number 4 is processed. Therefore, the operational circuit 106 makes the data SO "1", and rewrites the context data on the discharge port number 68 in the nozzle context memory 105 to "1", as shown in Fig. 3B at line number 5, and also, the head drive data DO to "0". When the processes are completed up to the discharge port number 128 with respect to the line number 4 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 65, 66, 67, and 68 to "0", "3", "0", and "1", respectively, as indicated by the line number 5 in Fig. 3B. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 0, 0, 0, 0 of the line number 4 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 7A, respectively. Thereafter, the processes will be executed in the same manner for the second scan with respect to the line numbers 5, 6, 7, etc. up to the last line. B-3. [Third Scan] Now, the description will be made of the processes at the time of third scan. For the third scan, the recording positions are displaced from those for the first scan and the second scan as shown in Fig. 5B. The discharge port numbers 33 to 36 of the recording head 1 correspond to the pixel arrays 1001 to 1004. (Line process for the Line Number 1) For recording of the line number 1, the line counter 103 indicates the line number 1, while the port counter 104 indicates the numbers from 1, 2, 3, etc. sequentially for processing. For the third scan, the pixel array 1001 is recorded by use of the discharge port number 33. Now, hereinafter, the description will be made of the processes corresponding to the pixel arrays 1001 to 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1001, is "1", while referring to Fig. 3C, the context data SO on the discharge port number 33 in the nozzle context memory 105 corresponding thereto is "0". Also, the input and output relationship with respect to the processes of the operational circuit 106, which correspond to the discharge port numbers 33 to 36, are those shown in Fig. 14B. Therefore, the operational circuit 106 outputs "1" as the nozzle context data SO, and also, outputs "0" as the head drive data DO. In this way, the context data on the discharge port number 33 in the nozzle context memory 105 is rewritten to "1". Now, the port counter 104 indicates the discharge port number 34 corresponding to the pixel array 1002 as shown in Fig. 5B. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1002, is "0", while referring to Fig. 3C, the context data on the discharge port number 34 in the nozzle context memory 105 corresponding thereto is "0". Therefore, due to the input and output relationship shown in Fig. 14B the operational circuit 106 outputs "1" as the nozzle context data SO and "0" as the head drive data DO. In this way, the context data on the discharge port number 34 in the nozzle context memory 105 is rewritten to ''0". Now, as shown in Fig. 5B, the port counter 104 indicates the discharge port number 35 corresponding to the pixel array 1003 at the time of third scan. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1003, is "1", while, referring to Fig. 3C, the context data on the discharge port number 35 in the nozzle context memory 105 corresponding thereto is "0". Therefore, due to the input and output relationship shown in Fig. 14B, the operational circuit 106 outputs "1" as the nozzle context data SO and "0" as the head drive data DO. In this way, the context data on the discharge port number 35 in the nozzle context memory 105 is rewritten to "1". Now, as shown in Fig. 5B, the port counter 104 indicates the discharge port number 36 corresponding to the pixel array 1004 at the time of third scan. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1004, is "1", while referring to Fig. 3C, the context data on the discharge port number 36 in the nozzle context memory 105 corresponding thereto is "0". Therefore, due to the input and output relationship shown in Fig. 14B, the operational circuit 106 outputs "1" as the nozzle context data SO and "0" as the head drive data DO. In this way, the context of the discharge port number 36 in the nozzle context memory 105 is rewritten to "1". When the processes are completed up to the discharge port number 128 with respect to the line number 1 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 33, 34, 35, and 36 to "1", "0", "1", and "1", respectively, as indicated by the line number 2 shown in Fig. 3C. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 0, 0, 0, 0 of the line number 1 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 7C, respectively. (Line Process for the Line Number 2) After the line process described above for the line number 1, the line counter 103 indicates the next line number 2. The port counter 104 is increased to 1, 2, 3, etc. sequentially for processing. Hereinafter, the description will be made of the processes for the discharge port numbers 33 to 36 corresponding to the pixel arrays 1001 to 1004. The data DI from the output buffer 102 that corresponds to the line number 2 of the pixel array 1001 is "1" as shown in Fig. 2, while the context data SI on the discharge port number 33 of the context memory 105 corresponding thereto is "1" as shown in Fig. 3C. Therefore, due to the input and output relationship shown in Fig. 14B, the operational circuit 106 makes the data SO "2", and rewrites the context data on the discharge port number 33 in the nozzle context memory 105 to "2", and also, the head drive data DO to "1". Now, the port counter 104 indicates the discharge port number 34 corresponding to the pixel array 1002. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 2 of the pixel array 1002, is "1", while, referring to Fig. 3C, the context data SI on the discharge port number 34 in the nozzle context memory 105 corresponding thereto is "0". Therefore, due to the input and output relationship shown in Fig. 14B, the operational circuit 106 makes the data SO "1", and rewrites the context data on the discharge port number 34 in the nozzle context memory 105 to "1", and also, the head drive data D0 to "0". Now, the port counter 104 indicates the discharge port number 35 corresponding to the pixel array 1003. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 2 of the pixel array 1003, is "1", while referring to Fig. 3C, the context data on the discharge port number 35 in the nozzle context memory 105 corresponding thereto is "1". Therefore, due to the input and output relationship shown in Fig. 14B, the operational circuit 106 makes the data SO "2", and rewrites the context data on the discharge port number 35 in the nozzle context memory to "2", and also, the head drive data DO to "1". Now, the port counter 104 indicates the discharge port number 36 corresponding to the pixel array 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 2 of the pixel array 1004, is "0", while referring to Fig. 3B, the context data on the discharge port number 36 in the nozzle context memory 105 corresponding thereto is "1". Therefore, due to the input and output relationship shown in Fig. 14B, the operational circuit 106 makes the data SO "1", and rewrites the context data on the discharge port number 36 in the nozzle context memory 105 to "1", and also, the head drive data DO to "0". When the processes are completed for all the discharge port numbers with respect to the line number 2 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 33, 34, 35, and 36 to "2", "1", "2", and "1", respectively, as indicated by the line number 3 in Fig. 3C. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 0, 0, 0, 0 of the line number 2 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 7C, respectively. (Line Process for the Line Number 3) After the line process described above for the line number 2, the line counter 103 indicates the next line number 3. The port counter 104 indicates 1, 2, 3, etc. sequentially for processing. Now, hereinafter, the description will be made of the processes for the discharge port numbers 33 to 36 corresponding to the pixel arrays 1001 to 1004. The data DI from the output buffer 102 that corresponds to the line number 3 of the pixel array 1001 is "1" as shown in Fig. 2, while the context data SI on the discharge port number 33 of the context memory 105 corresponding thereto is "2" as shown in Fig. 3C. Therefore, the operational circuit 106 makes the data SO "3", and rewrites the context data on the discharge port number 33 in the nozzle context memory to "3", and also, the head drive data DO to "1". Now, the port counter 104 indicates the discharge port number 33 corresponding to the pixel array 1002. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 3 of the pixel array 1002, is "1", while, referring to Fig. 3C, the context data on the discharge port number 34 in the nozzle context memory 105 corresponding thereto is "1". Therefore, the operational circuit 106 makes the data SO "2", and rewrites the context of the discharge port number 34 in the nozzle context memory 105 to "2", and also, the head drive data DO to "1". Now, the port counter 104 indicates the discharge port number 35 corresponding to the pixel array 1003. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 3 of the pixel array 1003, is "1", while referring to Fig. 3C, the context data on the discharge port number 35 in the nozzle context memory 105 corresponding thereto is "2". Therefore, the operational circuit 106 makes the data SO "3", and rewrites the context data on the discharge port number 35 in the nozzle context memory to "3", and also, the head drive data DO to "1". Now, the port counter 104 indicates the discharge port number 36 corresponding to the pixel array 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 3 of the pixel array 1004, is "0", while referring to Fig. 3C, the context data on the discharge port number 36 in the nozzle context memory 105 corresponding thereto is "1". Therefore, the operational circuit 106 makes the data SO "1", and rewrites the context data on the discharge port number 36 in the nozzle context memory 105 to "1", and also, the head drive data DO to "0". When the processes are completed up to the discharge port number 128 with respect to the line number 3 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 33, 34, 35, and 36 to "3", "2", "3", and "1", respectively, as indicated by the line number 4 in Fig. 3C. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 1, 0, 1, 0 of the line number 3 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 7C, respectively. (Line Process for the Line Number 4) After the line process described above for the line number 3, the line counter 103 indicates the next line number 4. Also, the port counter 104 indicates 1, 2, 3, etc. sequentially for processing. Now, hereinafter, the description will be made of the processes for the discharge port numbers 33 to 36 corresponding to the pixel arrays 1001 to 1004. The data DI from the output buffer 102 that corresponds to the line number 4 of the pixel array 1001 is "1" as shown in Fig. 2, while the context data SI on the discharge port number 33 of the context memory 105 corresponding thereto is "3" as shown in Fig. 3C. Therefore, the operational circuit 106 makes the data SO "0", and rewrites the context data on the discharge port number 33 in the nozzle context memory to "0", and also, the head drive data DO to "0". Now, the port counter 104 indicates the discharge port number 34 corresponding to the pixel array 1002. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 4 of the pixel array 1002, is "1", while, referring to Fig. 3C, the context data SI on the discharge port number 34 in the nozzle context memory 105 corresponding thereto is "2". Therefore, the operational circuit 106 makes the data SO "3", and rewrites the context data on the discharge port number 34 in the nozzle context memory 105 to "3", and also, the head drive data DO to "1". Now, the port counter 104 indicates the discharge port number 35 corresponding to the pixel array 1003. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 4 of the pixel array 1003, is "1", while referring to Fig. 3C, the context data SI on the discharge port number 35 in the nozzle context memory 105 corresponding thereto is "3". Therefore, the operational circuit 106 makes the data SO "0", and rewrites the context data on the discharge port number 35 in the nozzle context memory to "0", and also, the head drive data DO to "0". Now, the port counter 104 indicates the discharge port number 36 corresponding to the pixel array 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 4 of the pixel array 1004, is "0", while referring to Fig. 3C, the context data on the discharge port number 36 in the nozzle context memory 105 corresponding thereto is "1". Therefore, the operational circuit 106 makes the data SO "1", and rewrites the context data on the discharge port number 36 in the nozzle context memory 105 to "1", and also, the head drive data DO to "0". When the processes are completed up to the discharge port number 128 with respect to the line number 4 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 33, 34, 35, and 36 to "0", "3", "0", and "1", respectively, as indicated by the line number 5 in Fig. 3C. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 0, 1, 0, 0 of the line number 4 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 7C, respectively. Thereafter, the processes will be executed in the same manner for the third scan with respect to the line numbers 5, 6, 7, etc. up to the last line. B-4. [Fourth Scan] Now, the description will be made of the processes at the time of fourth scan. For the fourth scan, the recording positions are displaced from those for the previous scans. The discharge port numbers 1 to 4 of the recording head 1 correspond to the pixel arrays 1001 to 1004. (Line process for the Line Number 1) For recording of the line number 1, the line counter 103 indicates the line number 1, while the port counter 104 indicates the numbers from 1, 2, 3, etc. sequentially for processing. Now, hereinafter, the description will be made of the processes of the discharge port numbers 1 to 4 corresponding to the pixel arrays 1001 to 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1001, is "1", while referring to Fig. 3D, the context data SO on the discharge port number 1 in the nozzle context memory 105 corresponding thereto is "0". Also, the input and output relationship with respect to the processes of the operational circuit 106, which correspond to the discharge port numbers 1 to 4, are those shown in Fig. 14A. Therefore, the operational circuit 106 outputs "1" as the nozzle context data SO, and outputs "0" as the head drive data DO. In this way, the context data on the discharge port number 1 in the nozzle context memory 105 is rewritten to "0". Now, the port counter 104 indicates the discharge port number 2 corresponding to the pixel array 1002 as shown in Fig. 5B at the fourth scan. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1002, is "0", while referring to Fig. 3D, the context data on the discharge port number 2 in the nozzle context memory 105 corresponding thereto is "0". Therefore, due to the input and output relationship shown in Fig. 14A the operational circuit 106 outputs "0" as the nozzle context data SO, and also, "0" as the head drive data DO. In this way, the context data on the discharge port number 2 in the nozzle context memory 105 is rewritten to "0", Now, as shown in Fig. 5B, the port counter 104 indicates the discharge port number 3 corresponding to the pixel array 1003 at the time of fourth scan. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1003, is "1", while, referring to Fig. 3D, the context data on the discharge port number 3 in the nozzle context memory 105 corresponding thereto is "0". Therefore, due to the input and output relationship shown in Fig. 14A, the operational circuit 106 outputs "1" as the nozzle context data SO and "0" as the head drive data DO. In this way, the context data on the discharge port number 3 in the nozzle context memory 105 is rewritten to "1". Now, as shown in Fig. 5B, the port counter 104 indicates the discharge port number 4 corresponding to the pixel array 1004 at the time of fourth scan. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1004, is "1", while referring to Fig. 3D, the context data on the discharge port number 4 in the nozzle context memory 105 corresponding thereto is "0". Therefore, due to the input and output relationship shown in Fig. 14A, the operational circuit 106 outputs "1" as the nozzle context data SO and "0" as the head drive data DO. In this way, the context of the discharge port number 4 in the nozzle context memory 105 is rewritten to "1". When the processes are completed up to the discharge port number 128 with respect to the line number 1 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 1, 2, 3, and 4 to "1", "0", "1", and "1", respectively, as indicated by the line number 2 shown in Fig. 3D. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 0, 0, 0, 0 of the line number 1 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 7D, respectively. (Line Process for the Line Number 2) After the line process described above for the line number 1, the line counter 103 indicates the next line number 2. The port counter 104 indicates 1, 2, 3, etc. sequentially for processing. Hereinafter, the description will be made of the processes for the discharge port numbers 1 to 4 corresponding to the pixel arrays 1001 to 1004. The data DI from the output buffer 102 that corresponds to the line number 2 of the pixel array 1001 is "1" as shown in Fig. 2, while the context data SI on the discharge port number 1 of the context memory 105 corresponding thereto is "1" as shown in Fig. 3D. Therefore, due to the input and output relationship shown in Fig. 14A, the operational circuit 106 makes the data SO "2", and rewrites the context data on the discharge port number 2 in the nozzle context memory 105 to "2", and also, the head drive data DO to "1". Now, the port counter 104 indicates the discharge port number 2 corresponding to the pixel array 1002. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 2 of the pixel array 1002, is "1", while, referring to Fig. 3D, the context data SI on the discharge port number 2 in the nozzle context memory 105 corresponding thereto is "0". Therefore, due to the input and output relationship shown in Fig. 14A, the operational circuit 106 makes the data SO "1", and rewrites the context data on the discharge port number 2 in the nozzle context memory 105 to "1", and also, the head drive data DO to "0". Now, the port counter 104 indicates the discharge port number 3 corresponding to the pixel array 1003. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 2 of the pixel array 1003, is "1", while referring to Fig. 3D, the context data on the discharge port number 3 in the nozzle context memory 105 corresponding thereto is "1". Therefore, due to the input and output relationship shown in Fig. 14A, the operational circuit 106 makes the data SO "2", and rewrites the context data on the discharge port number 3 in the nozzle context memory to "2", and also, the head drive data DO to "1". Now, the port counter 104 indicates the discharge port number 4 corresponding to the pixel array 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 2 of the pixel array 1004, is "0", while referring to Fig. 3A, the context data on the discharge port number 4 in the nozzle context memory 105 corresponding thereto is "1". Therefore, due to the input and output relationship shown in Fig. 14A, the operational circuit 106 makes the data SO "1", and rewrites the context data on the discharge port number 4 in the nozzle context memory 105 to "1", and the head drive data DO to "0". When the processes are completed for the discharge port numbers up to 128 with respect to the line number 2 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 1, 2, 3, and 4 to "2", "1", "2", and "1", respectively, as indicated by the line number 3 in Fig. 3D. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 0, 0, 0, 0 of the line number 2 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 7D, respectively. (Line Process for the Line Number 3) After the line process described above for the line number 2, the line counter 103 indicates the next line number 3. The port counter 104 indicates 1, 2, 3, etc. sequentially for processing. Now, hereinafter, the description will be made of the processes for the discharge port numbers 1 to 4 corresponding to the pixel arrays 1001 to 1004. The data DI from the output buffer 102 that corresponds to the line number 3 of the pixel array 1001 is "1" as shown in Fig. 2, while the context data SI on the discharge port number 3 of the context memory 105 corresponding thereto is "2" as shown in Fig. 3D. Therefore, the operational circuit 106 makes the data SO "3", and rewrites the context data on the discharge port number 3 in the nozzle context memory to "3", and also, the head drive data DO to "0". Now, the port counter 104 indicates the discharge port number 2 corresponding to the pixel array 1002. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 3 of the pixel array 1002, is "1", while, referring to Fig. 3D, the context data on the discharge port number 3 in the nozzle context memory 105 corresponding thereto is "1". Therefore, the operational circuit 106 makes the data SO "2", and rewrites the context of the discharge port number 34 in the nozzle context memory 105 to "2", and also, the head drive data DO to "1". Now, the port counter 104 indicates the discharge port number 3 corresponding to the pixel array 1003. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 3 of the pixel array 1003, is "1", while referring to Fig. 3D, the context data on the discharge port number 3 in the nozzle context memory 105 corresponding thereto is "2". Therefore, the operational circuit 106 makes the data SO "3", and rewrites the context data on the discharge port number 3 in the nozzle context memory to "3", and also, the head drive data DO to "0". Now, the port counter 104 indicates the discharge port number 4 corresponding to the pixel array 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 3 of the pixel array 1004, is "0", while referring to Fig. 3D, the context data on the discharge port number 4 in the nozzle context memory 105 corresponding thereto is "1". Therefore, the operational circuit 106 makes the data SO "1", and rewrites the context data on the discharge port number 4 in the nozzle context memory 105 to "1", and also, the head drive data DO to "0". When the processes are completed up to the discharge port number 128 with respect to the line number 3 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 1, 2, 3, and 4 to "3", "2", "3", and "1", respectively, as indicated by the line number 4 in Fig. 3D. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 0, 0, 0, 0 of the line number 3 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 7D, respectively. (Line Process for the Line Number 4) After the line process described above for the line number 3, the line counter 103 indicates the next line number 4. Also, the port counter 104 indicates 1, 2, 3, etc. sequentially for processing. Now, hereinafter, the description will be made of the processes for the discharge port numbers 1 to 4 corresponding to the pixel arrays 1001 to 1004. The data DI from the output buffer 102 that corresponds to the line number 4 of the pixel array 1001 is "1" as shown in Fig. 2, while the context data SI on the discharge port number 1 of the context memory 105 corresponding thereto is "3" as shown in Fig. 3D. Therefore, the operational circuit 106 makes the data SO "0", and rewrites the context data on the discharge port number 33 in the nozzle context memory to "0", and the head drive data DO to "1". Now, the port counter 104 indicates the discharge port number 2 corresponding to the pixel array 1002. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 4 of the pixel array 1002, is "1", while, referring to Fig. 3D, the context data SI on the discharge port number 2 in the nozzle context memory 105 corresponding thereto is "2". Therefore, the operational circuit 106 makes the data SO "3", and rewrites the context data on the discharge port number 34 in the nozzle context memory 105 to "3", and also, the head drive data DO to "0". Now, the port counter 104 indicates the discharge port number 3 corresponding to the pixel array 1003. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 4 of the pixel array 1003, is "1", while referring to Fig. 3D, the context data SI on the discharge port number 3 in the nozzle context memory 105 corresponding thereto is "3". Therefore, the operational circuit 106 makes the data SO "0", and rewrites the context data on the discharge port number 3 in the nozzle context memory to "0", and the head drive data DO to "1". Now, the port counter 104 indicates the discharge port number 4 corresponding to the pixel array 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 4 of the pixel array 1004, is "0", while referring to Fig. 3D, the context data on the discharge port number 4 in the nozzle context memory 105 corresponding thereto is "1". Therefore, the operational circuit 106 makes the data SO "1", and rewrites the context data on the discharge port number 4 in the nozzle context memory 105 to "1", and the head drive data D0 to "0". When the processes are completed up to the discharge port number 128 with respect to the line number 4 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 1, 2, 3, and 4 to "0", "3", "0", and "1", respectively, as indicated by the line number 5 in Fig. 3D. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 1, 0, 1, 0 of the line number 4 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 7A, respectively. Thereafter, the processes will be executed in the same manner for the fourth scan with respect to the line numbers 5, 6, 7, etc. up to the last line. As described above, with the structure arranged to record in such a manner that the recording in a given area is completed by means of a plurality of recording scans, and at the same time, the positions of the discharge ports of a recording head corresponding to the given area are made different per scan, it is possible to obtain the data that indicate discharge / non-discharge of ink per recording scan by calculation using the output from the output buffer 102 that stores. the recording data, as well as using the context data to which the data to be formed at the time of such recording scan are assigned. Therefore, with the provision of the memory that stores the context data corresponding to the numbers of discharge ports of the recording head, it is possible to obtain the discharge data per scan. As a result, there is no need for the preparation and storage of recording data per scan as in the conventional art, hence making it possible to make the memory capacity smaller, and implement the reduction of costs of the apparatus. Also, with the use of the context memory 105 described in the present embodiment, a given pixel array is formed by several scans in accordance with the discharge data per scan obtainable by the operational circuit shown in Fig. 4, and at the same time, the pixels to be recorded in the pixel array can be recorded sequentially by the discharge ports corresponding to each scan in turn, as shown in Fig. 8 for array 1001. Therefore, it is possible to make the frequencies of use of the discharge ports more uniform, thus reducing the occurrence of defective discharges. Also, even if any defective discharges take place, it is possible to scatter the positions of pixels where no recording is made. As a result, it is possible to minimize the degradation of quality of images to be recorded. (Second Embodiment) Now, with reference to the accompanying drawings, the detailed description will be made of a second embodiment in accordance with the present invention. For the first embodiment, the described example is that an image in a given area is recorded by the application of four-time scans by use of a recording head provided with 128 discharge ports. In accordance with the present embodiment, recording is made by the two-time scans that uses a recording head 1 provided with 128 discharge ports. Fig. 9A is a view which shows the recording head 1 having 128 discharge ports, #1 to #128. In Fig. 9B, a reference mark PA designates the first scanning position of the recording head 1 with respect to a recording material, and PB, the second scanning position thereof to follow. In Fig. 9B, reference numerals 1001, 1002, 1003, and 1004 designate pixel arrays in the scanning direction of the head 1, respectively. Also, in Fig. 9B, each number with a mark # designates each of the discharge port numbers of the recording head 1. With the structure described above, an image is formed on the pixel array 1001 in the head scanning direction, for example, by the application of ink discharges from the discharge ports numbers #65 and #1 at the first and second scans, respectively. The principal part of a printing apparatus of the present embodiment is the same as the one represented in Fig. 1. Therefore, the detailed description thereof will be omitted. In accordance with the present embodiment, however, the nozzle context memory 105 is arranged to store three-bit data for each discharge port number. By the adoption of the three-bit context data, seven states are provided for "1" to "7". Fig. 15A and Fig. 15B are truth tables that illustrate the outputs of the operational circuit 106 for all inputs in the present embodiment. In Fig. 15A and Fig. 15B, the input from the output buffer 102 is defined as DI; the output to the head driver controller, as DO; the input from the nozzle context memory 105, as SI; and the output to the nozzle context memory 105, as SO as in the first embodiment. Also, the input DI from the output buffer 102 and the output DO to the head driver controller 107 are one-bit information, respectively. Here, "1" means ink discharge, and "0", non-discharge thereof. Also, the input and output SI and SO to and from the nozzle context memory 105 are three-bit information. Here, the seven states from "1" to "7" are obtainable. Also, for the discharge port numbers 1 to 64, processes are executed as shown in Fig. 15A. For the discharge port numbers 65 to 128, processes are executed as shown in Fig. 15B. Fig. 12 is a view which shows one example of a circuit structured in the operational circuit 106 for the executions of processes described in Fig. 15A and Fig. 15B. In Fig. 12, a reference numeral 125 designates an exclusive OR gate that executes an exclusive OR between SI1 and SI2 of the outputs SI (SI0, SI1, and SI2) of the three-bit structured nozzle context memory 105, and 121, a selector that selects either one of the input from the terminals A0, A1, and A2 or from the terminals B0, B1, and B2, and makes its output from the terminals Y0, Y1, and Y2. Each input from the terminals A0, A1, and A2 is the output SI from the nozzle context memory 105. Each input from the terminals B0, B1, and B2 is the signal provided by shifting the bits of the output SI from the nozzle context memory 105 and the output from the exclusive OR gate 125. A reference numeral 122 designates an invertor that inverts the output SI2 from the nozzle context memory 105; 123, a selector that selects the decoder outputs in accordance with the discharge port numbers; and 124, an AND circuit. Here, each of the selectors 121 and 123 outputs the inputted signals from the A side to Y when the XSELA is at "0". When it is at "1", the signals from the B side are output to Y. For selector 123, the nozzle number signals are input as "1" when the nozzle numbers (discharge port numbers) are 1 to 64, and as "0" when the numbers are 65 to 128. Now, the operation of the circuit shown in Fig. 12 will be described. At first, when the DI is "0", the selector 12 outputs the A side to Y, thus making SO = SI, while the DO is "0" by means of AND 124. Also, when the DI is "1", the selector 121 outputs the B side to Y. When the DI is "1" and the SI is "0", that is, SI0 = "0", SI1 = "0", and SI2 = "0", SO0 becomes "0" because it is the exclusive OR between SI1 and SI2, and SO1 = SI0 = "0", SO2 = SI2 = "0". Thus, as shown in Figs. 15A and 15B, the SO is "0". Also, when DI is "1" and SI is "1", that is, SI0 = "1", SI1 = "0", and SI2 = "0", the SO is "2", because the SOO becomes "0" as it is the exclusive OR between SI1 and SI2, and SO1 = SI0 = "1", SO2 = SI1 = "0". Fig. 10A and Fig. 10B are views that show schematically the successive contents of the nozzle context memory 105 as the line number increments during the first and second scans respectively, as shown in Fig. 9B, when the image shown in Fig. 6 is being recorded with the structure arranged as in the present embodiment. In Fig. 10A and Fig. 10B, reference numerals 1001, 1002, 1003, and 1004 designate pixel arrays in the scanning direction of the head, respectively, which correspond to the pixel arrays represented in Fig. 6 and Fig. 9B. Also, reference numerals 1 to 16 designate the line numbers that indicate each line in the head scanning direction. Now, the detailed description will be made of the recording operation of the present embodiment in accordance with a specific example. A. [Specific Example of the Operation] At first, with reference to Fig. 1, the recording operation will be described with regard to the image shown in Fig. 6 by dividing it into the first and second scans. Here, for the present embodiment, it is assumed that the nozzle context memory 105 is set at "1" by means of the main controller 101 before each scan. The data on the image to be recorded are the same as those for the first embodiment, that is, the data represented in Fig. 2. Also, of the data to be recorded by the first scan and the second scan for the present embodiment, the data on the pixel arrays 1001 to 1004 are shown in Fig. 11A and Fig. 11B. A-1. [First Scan] (Line Process for the Line Number 1) In executing the line process for the line number 1, the line counter 103 indicates the line number 1, and the port counter 104 indicates the discharge port numbers 1, 2, 3, etc. sequentially for processing. At first, the description will be made of the process corresponding to the discharge port number 65 assigned to the pixel array 1001. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1001, is "1", while referring to Fig. 10A, the context data SI on the discharge port number 65 in the nozzle context memory 105 corresponding thereto is "1" when line number 1 is processed. Therefore, as shown in Fig. 15B, the operational circuit 106 makes the data SO "2" and rewrites the context of the discharge port number 65 in the nozzle context memory 105 to "2", as shown in Fig. 10A at line number 2. The output head drive data DO is made "0". Then, the port counter 104 indicates the discharge port number 66 that corresponds to the pixel array 1002. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1002, is "0", while referring to Fig. 10A, the context data SI on the discharge port number 66 in the nozzle context memory 105 corresponding thereto is "1" when line number 1 is processed. Therefore, as shown in Fig. 15B, the operational circuit 106 makes the data SO "1", and rewrites the context of the discharge port number 66 in the nozzle context memory 105 to "1", as shown in Fig. 10A at line number 2. Also, the output head drive data DO is made "0". Now, the port counter 104 indicates the discharge port number 67 corresponding to the pixel array 1003. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1003, is "1", while referring to Fig. 10A, the context data SI on the discharge port number 68 in the nozzle context memory 105 corresponding thereto is "1" when line number 1 is processed. Therefore, as shown in Fig. 15B, the operational circuit 106 makes the data SO "2", and rewrites the context of the discharge port number 68 in the nozzle context memory 105 to "2", as shown in Fig. 10A at line number 2. The output head drive data DO is made "0". Now, the port counter 104 indicates the discharge port number 68 that corresponds to the pixel array 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1004, is "'1", while referring to Fig. 10A, the context data SI on the discharge port number 68 in the nozzle context memory 105 corresponding thereto is "1" when line number 1 is processed. Therefore, as shown in Fig. 15B, the operational circuit 106 makes the data SO "2", and rewrites the context of the discharge port number 68 in the nozzle context memory 105 to "2", as shown in Fig. 10A at line number 2. The output head drive data DO is made "0". When the processes are completed up to the discharge port number 128 with respect to the line number 1 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 65, 66, 67, and 68 to "2", "1", "2", and "2", respectively, as indicated by the line number 2 in Fig. 10A. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 0, 0, 0, 0 as indicated by the line number 1 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 11A, respectively. (Line Process for the Line Number 2) Now, the line counter 103 indicates the line number 2, and the port counter 104 indicates the discharge port number 1, 2, 3, etc. sequentially for processing. Hereinafter, the description will be made of the data processes corresponding to the discharge numbers 65 to 68 corresponding to the pixel arrays 1001 to 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 2 of the pixel array 1001, is "1", while referring to Fig. 10A, the context data SI on the discharge port number 65 in the nozzle context memory 105 corresponding thereto is "2". Therefore, as shown in Fig. 15B, the operational circuit 106 makes the data SO "5" and rewrites the context of the discharge port number 65 in the nozzle context memory 105 to "5". The output head drive data DO is made "0". Then, the port counter 104 indicates the discharge port number 66 that corresponds to the pixel array 1002. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 2 of the pixel array 1002, is "1", while referring to Fig. 10A, the context data SI on the discharge port number 66 in the nozzle context memory 105 corresponding thereto is "1". Therefore, as shown in Fig. 15B, the operational circuit 106 makes the data SO "2", and rewrites the context of the discharge port number 66 in the nozzle context memory 105 to "2". Also, the output head drive data DO is made "0". Now, the port counter 104 indicates the discharge port number 67 corresponding to the pixel array 1003. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 2 of the pixel array 1003, is "1", while referring to Fig. 10A, the context data SI on the discharge port number 68 in the nozzle context memory 105 corresponding thereto is "2". Therefore, as shown in Fig. 15B, the operational circuit 106 makes the data SO "5", and rewrites the context of the discharge port number 68 in the nozzle context memory 105 to "5". The output head drive data DO is made "0". Now, the port counter 104 indicates the discharge port number 68 that corresponds to the pixel array 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 2 of the pixel array 1004, is "0", while referring to Fig. 10A, the context data SI on the discharge port number 68 in the nozzle context memory 105 corresponding thereto is "2". Therefore, as shown in Fig. 15B, the operational circuit 106 makes the data SO "2", and rewrites the context of the discharge port number 68 in the nozzle context memory 105 to "2". The output head drive data DO is made "0". When the processes are completed up to the discharge port number 128 with respect to the line number 2 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 65, 66, 67, and 68 to "5", "2", "5", and "2", respectively, as indicated by the line number 3 in Fig. 10A. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 0, 0, 0, 0 as indicated by the line number 2 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 11A, respectively. (Line Process for the Line number 3) Now, the processes for the line number 3 will be described. The line counter 103 indicates the line number 3, and the port counter 104 indicates the discharge port number 1, 2, 3, etc. sequentially for processing. Hereinafter, the description will be made of the data processes corresponding to the discharge numbers 65 to 68 corresponding to the pixel arrays 1001 to 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 3 of the pixel array 1001, is "1", while referring to Fig. 10A, the context data SI on the discharge port number 65 in the nozzle context memory 105 corresponding thereto is "5". Therefore, as shown in Fig. 15B, the operational circuit 106 makes the data SO "3" and rewrites the context of the discharge port number 65 in the nozzle context memory 105 to "3". The output head drive data DO is made "1". Then, the port counter 104 indicates the discharge port number 66 that corresponds to the pixel array 1002. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 3 of the pixel array 1002, is "1", while referring to Fig. 10A, the context data SI on the discharge port number 66 in the nozzle context memory 105 corresponding thereto is "2". Therefore, as shown in Fig. 15B, the operational circuit 106 makes the data SO "5", and rewrites the context of the discharge port number 66 in the nozzle context memory 105 to "5". Also, the output head drive data DO is made "0". Now, the port counter 104 indicates the discharge port number 67 corresponding to the pixel array 1003. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 3 of the pixel array 1003, is "1", while referring to Fig. 10A, the context data SI on the discharge port number 68 in the nozzle context memory 105 corresponding thereto is "5". Therefore, as shown in Fig. 15B, the operational circuit 106 makes the data SO "3", and rewrites the context of the discharge port number 68 in the nozzle context memory 105 to "3". The output head drive data DO is made "1". Now, the port counter 104 indicates the discharge port number 68 that corresponds to the pixel array 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 3 of the pixel array 1004, is "0", while referring to Fig. 10A, the context data SI on the discharge port number 68 in the nozzle context memory 105 corresponding thereto is "2". Therefore, as shown in Fig. 15B, the operational circuit 106 makes the data SO "2", and rewrites the context of the discharge port number 68 in the nozzle context memory 105 to "2". The output head drive data DO is made "0". When the processes are completed up to the discharge port number 128 with respect to the line number 3 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 65, 66, 67, and 68 to "3", "5", "3", and "2", respectively, as indicated by the line number 4 in Fig. 10A. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 1, 0, 1, 0 as indicated by the line number 3 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 11A, respectively. (Line Process for the Line Number 4) Now, the processes for the line number 4 will be described. The line counter 103 indicates the line number 4, and the port counter 104 indicates the discharge port number 1, 2, 3, etc. sequentially for processing. Hereinafter, the description will be made of the data processes corresponding to the discharge numbers 65 to 68 corresponding to the pixel arrays 1001 to 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 4 of the pixel array 1001, is "1", while referring to Fig. 10A, the context data SI on the discharge port number 65 in the nozzle context memory 105 corresponding thereto is "3". Therefore, as shown in Fig. 15B, the operational circuit 106 makes the data SO "7" and rewrites the context of the discharge port number 65 in the nozzle context memory 105 to "7". The output head drive data DO is made "0". Then, the port counter 104 indicates the discharge port number 66 that corresponds to the pixel array 1002. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 4 of the pixel array 1002, is "0", while referring to Fig. 10A, the context data SI on the discharge port number 66 in the nozzle context memory 105 corresponding thereto is "1". Therefore, as shown in Fig. 15B, the operational circuit 106 makes the data SO "3", and rewrites the context of the discharge port number 66 in the nozzle context memory 105 to "3". Also, the output head drive data DO is made "1". Now, the port counter 104 indicates the discharge port number 67 corresponding to the pixel array 1003. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 4 of the pixel array 1003, is "1", while referring to Fig. 10A, the context data SI on the discharge port number 68 in the nozzle context memory 105 corresponding thereto is "1". Therefore, as shown in Fig. 15B, the operational circuit 106 makes the data SO "7", and rewrites the context of the discharge port number 68 in the nozzle context memory 105 to "7". The output head drive data DO is made "0". Now, the port counter 104 indicates the discharge port number 68 that corresponds to the pixel array 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 4 of the pixel array 1004, is "0", while referring to Fig. 10A, the context data SI on the discharge port number 68 in the nozzle context memory 105 corresponding thereto is "1". Therefore, as shown in Fig. 15B, the operational circuit 106 makes the data SO "2", and rewrites the context of the discharge port number 68 in the nozzle context memory 105 to "2". The output head drive data DO is made "0". When the processes are completed up to the discharge port number 128 with respect to the line number 4 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 65, 66, 67, and 68 to "7", "3", "7", and "2", respectively, as indicated by the line number 5 in Fig. 10A. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 0, 1, 0, 0 as indicated by the line number 4 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 11A, respectively. Thereafter, the processes described above are executed in accordance with data on each line, and after the processes on the last line are completed, the processes for the second scan will begin. A-2. [Second Scan] Now., the processes at the second scan will be described. For the second scan, the discharge ports that correspond to the pixel arrays 1001 to 1004 described above are the discharge port numbers 1 to 4. As in the first scan, the data to be stored in the nozzle context memory 105 are set at "1" before scanning begins. (Line Process for the Line Number 1) In executing the line process for the line number 1, the line counter 103 indicates the line number 1, and the port counter 104 indicates the discharge port numbers 1, 2, 3, etc. sequentially for processing. Hereinafter, the description will be made of the data processes for the discharge numbers 1 to 4 assigned to the pixel arrays 1001 to 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1001, is "1", while referring to Fig. 10B, the context data SI on the discharge port number 1 in the nozzle context memory 105 corresponding thereto is "1". Therefore, as shown in Fig. 15A, the operational circuit 106 makes the data SO "2" and rewrites the context of the discharge port number 1 in the nozzle context memory 105 to "2". The output head drive data DO is made "0". Then, the port counter 104 indicates the discharge port number 2 that corresponds to the pixel array 1002. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1002, is "0", while referring to Fig. 10B, the context data SI on the discharge port number 2 in the nozzle context memory 105 corresponding thereto is "1". Therefore, as shown in Fig. 15A, the operational circuit 106 makes the data SO "1", and rewrites the context of the discharge port number 2 in the nozzle context memory 105 to "1". Also, the output head drive data DO is made "0". Now, the port counter 104 indicates the discharge port number 3 corresponding to the pixel array 1003. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1003, is "1", while referring to Fig. 10B, the context data SI on the discharge port number 3 in the nozzle context memory 105 corresponding thereto is "1". Therefore, as shown in Fig. 15A, the operational circuit 106 makes the data SO "2", and rewrites the context of the discharge port number 3 in the nozzle context memory 105 to "2". The output head drive data DO is made "1". Now, the port counter 104 indicates the discharge port number 4 that corresponds to the pixel array 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 1 of the pixel array 1004, is "1", while referring to Fig. 10B, the context data SI on the discharge port number 4 in the nozzle context memory 105 corresponding thereto is "1". Therefore, as shown in Fig. 15A, the operational circuit 106 makes the data SO "2", and rewrites the context of the discharge port number 4 in the nozzle context memory 105 to "2". The output head drive data DO is made "1". When the processes are completed up to the discharge port number 128 with respect to the line number 1 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 1, 2, 3, and 4 to "2", "1", "2", and "2", respectively, as indicated by the line number 2 in Fig. 10B. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 1, 0, 1, 1 as indicated by the line number 1 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 11B, respectively. (Line Process for the Line Number 2) Now, the processes for the line number 2 will be described. The line counter 103 indicates the line number 2, and the port counter 104 indicates the discharge port number 1, 2, 3, etc. sequentially for processing. Hereinafter, the description will be made of the data processes corresponding to the discharge numbers 1 to 4 assigned to the pixel arrays 1001 to 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 2 of the pixel array 1001, is "1", while referring to Fig. 10B, the context data SI on the discharge port number 1 in the nozzle context memory 105 corresponding thereto is "2". Therefore, as shown in Fig. 15A, the operational circuit 106 makes the data SO "5" and rewrites the context of the discharge port number 1 in the nozzle context memory 105 to "5". The output head drive data DO is made "1". Then, the port counter 104 indicates the discharge port number 2 that corresponds to the pixel array 1002. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 2 of the pixel array 1002, is "1", while referring to Fig. 10B, the context data SI on the discharge port number-2 in the nozzle context memory 105 corresponding thereto is "1". Therefore, as shown in Fig. 15A, the operational circuit 106 makes the data SO "2", and rewrites the context of the discharge port number 66 in the nozzle context memory 105 to "2". Also, the output head drive data DO is made "1". Now, the port counter 104 indicates the discharge port number 3 corresponding to the pixel array 1003. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 2 of the pixel array 1003, is "1", while referring to Fig. 10B, the context data SI on the discharge port number 3 in the nozzle context memory 105 corresponding thereto is "2". Therefore, as shown in Fig. 15A, the operational circuit 106 makes the data SO "5", and rewrites the context of the discharge port number 3 in the nozzle context memory 105 to "5". The output head drive data DO is made "1". Now, the port counter 104 indicates the discharge port number 4 that corresponds to the pixel array 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 2 of the pixel array 1004, is "0", while referring to Fig. 10B, the context data SI on the discharge port number 4 in the nozzle context memory 105 corresponding thereto is "2". Therefore, as shown in Fig. 15A, the operational circuit 106 makes the data SO "2", and rewrites the context of the discharge port number 4 in the nozzle context memory 105 to "2". The output head drive data DO is made "0". When the processes are completed up to the discharge port number 128 with respect to the line number 2 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 1, 2, 3, and 4 to "5", "2", "5", and "2", respectively, as indicated by the line number 3 in Fig. 10B. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 1, 1, 1, 0 as indicated by the line number 2 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 11B, respectively. (Line Process for the Line number 3) Now, the processes for the line number 3 will be described. The line counter 103 indicates the line number 3, and the port counter 104 indicates the discharge port number 1, 2, 3, etc. sequentially for processing. Hereinafter, the description will be made of the data processes corresponding to the discharge numbers 1 to 4 assigned to the pixel arrays 1001 to 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 3 of the pixel array 1001, is "1", while referring to Fig. 10B, the context data SI on the discharge port number 1 in the nozzle context memory 105 corresponding thereto is "5". Therefore, as shown in Fig. 15A, the operational circuit 106 makes the data SO "5" and rewrites the context of the discharge port number 1 in the nozzle context memory 105 to "3". The output head drive data DO is made "1". Then, the port counter 104 indicates the discharge port number 2 that corresponds to the pixel array 1002. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 3 of the pixel array 1002, is "1", while referring to Fig. 10B, the context data SI on the discharge port number 2 in the nozzle context memory 105 corresponding thereto is "2". Therefore, as shown in Fig. 15A, the operational circuit 106 makes the data SO "5", and rewrites the context of the discharge port number 2 in the nozzle context memory 105 to "5". Also, the output head drive data DO is made "1". Now, the port counter 104 indicates the discharge port number 3 corresponding to the pixel array 1003. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 3 of the pixel array 1003, is "1", while referring to Fig. 10B, the context data SI on the discharge port number 3 in the nozzle context memory 105 corresponding thereto is "5". Therefore, as shown in Fig. 15A, the operational circuit 106 makes the data SO "3", and rewrites the context of the discharge port number 3 in the nozzle context memory 105 to "3". The output head drive data DO is made "0". Now, the port counter 104 indicates the discharge port number 4 that corresponds to the pixel array 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 3 of the pixel array 1004, is "0", while referring to Fig. 10B, the context data SI on the discharge port number 4 in the nozzle context memory 105 corresponding thereto is "2". Therefore, as shown in Fig. 15A, the operational circuit 106 makes the data SO "2", and rewrites the context of the discharge port number 4 in the nozzle context memory 105 to "2". The output head drive data DO is made "0". When the processes are completed up to the discharge port number 128 with respect to the line number 3 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 1, 2, 3, and 4 to "3", "5", "3", and "2", respectively, as indicated by the line number 4 in Fig. 10B. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 0, 1, 0, 0 as indicated by the line number 3 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 11B, respectively. (Line Process for the Line Number 4) Now, the processes for the line number 4 will be described. The line counter 103 indicates the line number 4, and the port counter 104 indicates the discharge port number 1, 2, 3, etc. sequentially for processing. Hereinafter, the description will be made of the data processes corresponding to the discharge numbers 1 to 4 assigned to the pixel arrays 1001 to 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 4 of the pixel array 1001, is "1", while referring to Fig. 10B, the context data SI on the discharge port number 1 in the nozzle context memory 105 corresponding thereto is "3". Therefore, as shown in Fig. 15A, the operational circuit 106 makes the data SO "7" and rewrites the context of the discharge port number 1 in the nozzle context memory 105 to "7". The output head drive data DO is made "1". Then, the port counter 104 indicates the discharge port number 2 that corresponds to the pixel array 1002. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 4 of the pixel array 1002, is "1'', while referring to Fig. 10B, the context data SI on the discharge port number 2 in the nozzle context memory 105 corresponding thereto is "5". Therefore, as shown in Fig. 15A, the operational circuit 106 makes the data SO "3'', and rewrites the context of the discharge port number 2 in the nozzle context memory 105 to "3". Also, the output head drive data DO is made "0". Now, the port counter 104 indicates the discharge port number 3 corresponding to the pixel array 1003. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 4 of the pixel array 1003, is "1", while referring to Fig. 10B, the context data SI on the discharge port number 3 in the nozzle context memory 105 corresponding thereto is "3". Therefore, as shown in Fig. 15A, the operational circuit 106 makes the data SO "7", and rewrites the context of the discharge port number 3 in the nozzle context memory 105 to "7". The output head drive data DO is made "1". Now, the port counter 104 indicates the discharge port number 4 that corresponds to the pixel array 1004. Referring to Fig. 2, the data DI from the output buffer 102, which corresponds to the line number 4 of the pixel array 1004, is "0", while referring to Fig. 10B, the context data SI on the discharge port number 4 in the nozzle context memory 105 corresponding thereto is "2". Therefore, as shown in Fig. 15A, the operational circuit 106 makes the data SO "2", and rewrites the context of the discharge port number 4 in the nozzle context memory 105 to "2". The output head drive data DO is made "0". When the processes are completed up to the discharge port number 128 with respect to the line number 4 in the manner as described above, the nozzle context memory 105 has rewritten the contexts of the discharge port numbers 1, 2, 3, and 4 to "7", "3", "7", and "2", respectively, as indicated by the line number 5 in Fig. 10B. Also, the drive data DO output from the operational circuit 106 are in agreement with the data 1, 0, 1, 0 as indicated by the line number 4 on the pixel arrays 1001, 1002, 1003, and 1004 shown in Fig. 11A, respectively. Fig. 13 is a view which shows the discharge ports used in the present embodiment for the formation of pixels in the pixel array 1001 in the scanning direction of the head 1. In Fig. 13, one square represents the position of one pixel formation. The square filled in black indicates the corresponding pixel is formed by discharged ink. Also, each of the numbers with the mark # represents each discharge port number. Numerals 1 to 16 designate line numbers in the scanning direction of the head 1. As understandable from Fig. 13, the discharge ports #1 and #65 for the formation of the pixel array 1001 are used four times each for discharging ink. By the use of the discharge ports as shown in the present embodiment, it is possible to use them uniformly. Thus, there is no deviation in the use frequencies of discharge ports. Therefore, the occurrence of defective discharges can be reduced, while making the life of the recording head longer. Also, even if there are discharge ports whose amount of ink discharge are defective, it is possible to scatter the positions of pixels that are not recorded, hence obtaining good images. (Third Embodiment) At first, before the description of the present embodiment, the structural example of the principal part of an ink jet printing apparatus for use of the present embodiment will be described with reference to Fig. 16. In Fig. 16, a recording head (printing head) 1 is provided with 128 ink discharge ports (not shown), for example, on the plane that faces a recording sheet 7 serving as a recording material in the conveying direction of the recording sheet 7. Also, the recording head 1 is provided with ink paths (not shown) conductively connected to each of the 128 discharge ports. On the base board that provides the recording head 1, electrothermal transducing elements are formed corresponding to each of the ink paths to generate thermal energy for ink discharges. The electrothermal transducing elements generate heat by the application of electric pulses in accordance with drive data. With heat thus generated, film boiling is created in ink. By the film boiling thus created, air bubbles are developed. Upon the development of the bubbles, ink is discharged from the discharge ports. For the ink paths, a common liquid chamber is provided and connected to each of them for its shared use. Ink retained in this chamber is supplied to each of the ink paths in accordance with the ink discharge operation in each of the ink paths. The recording head 1 is mounted on a carriage 2. The carriage 2 is slidably guided by a pair of guide rails 3 that extend in parallel with the recording surface of the recording sheet 7. Therefore, the recording head 1 can scan while traveling along the guide rails 3 in a state that it is mounted on the carriage 2. Along such scans, it discharges ink onto the recording surface for recording at a given timing. Then, the recording sheet 7 is sequentially carried for a given amount per scan in the direction indicated by an arrow in Fig. 16. With the repetition of such operations, recording is being made on the recording sheet sequentially. The conveyance of the recording sheet 7 is performed by the rotation of each pair of carrier rollers 4 and 5 arranged above and below the recording surface, respectively. Also, on the reverse side of the recording surface of the recording sheet 7, a platen 6 is arranged to keep the flatness of the recording surface. The carriage 2 can travel by means of a belt (not shown) attached thereto when it is driven by a motor. Also, the rotation of the carrier rollers 4 and 5 are possible by transmitting the rotation of a motor thereto. Now, when recording is made dividedly by the four-time scan as in the first embodiment described above, the recording sheet 7 serving as a recording material is carried per scan in the direction indicated by the arrow in Fig. 16 in a length equivalent to 1/4 of the extent of the array of all the discharge ports (128 ports). In accordance with a third embodiment of the present invention, the structure is arranged to provide a control so that the recording speed is enhanced depending on the selection of modes of use for the first embodiment. Here, the mode of use that requires the enhancement of the recording speed is the so-called draft mode described earlier. Such mode is selected when it takes a long time to obtain the result of a normal recording, while its recording result is needed immediately even if it is simplified, or when the required output of the result of recording is not very important, for example. Usually, for the draft mode, its recording speed is made faster by recording pixels intermittently like a checker pattern. Also, the draft mode is adopted for curtailing the ink consumption. For the present embodiment, only the first scan is executed for all the pixel arrays when the draft mode is selected in the first embodiment described above. After such first scan, the recording sheet 7 is carried in the direction indicated by the arrow in Fig. 16 in the length equivalent to the extent of the array of all the discharge ports (128 ports). Therefore, on the recording sheet 7, only approximately 1/4 of the pixels for normal recording are actually recorded. As a result, a higher speed recording can be implemented as required for the draft mode to the extent that the number of times of scanning and feeding of the recording sheet 7 are reduced with respect to the entire surface of the recording sheet 7. Further, if the numbers of pixels to be recorded are reduced, the pixels per discharge port are thinned almost uniformly, thus making it possible to enhance the drive frequency and make the scanning speed of the head 1 four times faster to implement the intended higher-speed recording. Furthermore, in accordance with the present embodiment, it is possible to repeat the first and third scans represented in Fig. 5 described for the first embodiment, and the recording sheet 7 is carried in the direction indicated by the arrow in Fig. 16 in an amount equivalent to half of the length of the array of the all the discharge ports while these scans are being executed. In this way, about 1/2 of the pixels for normal recording are recorded. Also, the present embodiment is applicable to the case where recording is executed by two-time scans as in the second embodiment described above. In other words, if the draft mode is selected in the second embodiment, only the first scan is executed for all the pixel arrays as described above, and after such first scan, the recording sheet 7 is carried in the direction indicated by the arrow in Fig. 16 in the length equivalent to the extent of the array of all the discharge ports (128 ports). Therefore, on the recording sheet 7, there are recorded only about 1/2 of pixels which are recorded normally, thus implementing a higher speed recording required as the draft mode. (Fourth Embodiment) Fig. 17, Fig. 18, and Fig. 19 are views that illustrate a fourth embodiment in accordance with the present invention. As in the third embodiment described above, the present embodiment is structured to execute only the first scan of the four scans represented in Fig. 5B described for the first embodiment, and to carry the recording sheet 7 in the direction indicated by the arrow in Fig. 16 in a length equivalent to the extent of the array of all the discharge ports. Further, the present embodiment is an application example where a data processing function, which will be described later, is additionally provided for recording edge portions of images. Here, the operational circuit 106 is assumed to execute the processes for the input and output relationship as shown in Fig. 14A with respect to all the discharge ports at the time of the first scan shown in Fig. 5B. Fig. 17 is a block diagram, which is equivalent to Fig. 1 used for the first embodiment described above. Here, the description will be made of only the parts that differ from those in Fig. 1. In Fig. 17, a reference numeral 211 designates a latch that holds the buffer output data DI corresponding to the line number that precedes by 1 the line number indicated by the line number counter 103. In other words, the latch 211 holds the data DI for each discharge port number as a binary data to indicate discharge or non-discharge of ink for the line number that precedes by 1 the line number currently in process. The latch 211 is connected to a comparator 212, and the data latched by the latch 211, that is, the data DI (hereinafter referred to as DI (t - 1)) on the line number that precedes by 1 the currently processed line number, and the output data from the output buffer 102, that is, the data DI on the currently processed line number, are compared for every discharge port number. Then, if the data DI (t - 1) is "0" (non-discharge) for the line number which precedes by 1 the currently processed line number and the data DI on the current line number is "1" (indicating discharge of ink), the output signal from the comparator 212 is "0". When the output of this comparator 212 is "0", the data SI output from the corresponding nozzle context memory 105 is reset to "0". In other words, on the image edge portion where data DI changes from "0" to "1" on the pixel array corresponding to each discharge port number, the nozzle context SI is reset to "0". As described above, by resetting the nozzle context SI to "0" on the image edge portion where the data DI changes from "0" to "1", the DO on the currently processed pixel becomes "1" if the pixel is among those on the edge portion. Hence, ink is discharged from the corresponding discharge port. Fig. 18 is a view which shows the changing state of the contents of the nozzle context memory 105 corresponding to the image data DO represented in Fig. 2 in accordance with the processes executed in the present embodiment. In this case, recording is executed as shown in Fig. 19, and the pixels on the edge portions of images are formed as can be understood from the comparison between the representations in Fig. 19 and Fig. 7A used for the first embodiment. As described above, in accordance with the present embodiment, the pixels on the edge portions are always set at "ink discharge" on the edge portions where the image data DI changes from "0" to "1". In this way, even for the mode where recording is executed by thinning the dots that would be recorded normally, there is no possibility that the dots on the edge portions are thinned, thus making it possible to record images whose character portion or the like are easily recognizable. In this respect, the point at which image data DI changes from "0" to "1" is detected as the edge portion of an image in accordance with the present embodiment. However, a structure may be arranged so that a comparison is made possible with the recording data on the next line, and then, the point at which the image data DI changes from "1" to "0" or the points of change both from "1" to "0" and "0" to "1" can be detected as the edge portion of the image. (Fifth Embodiment) The present embodiment adopts as its recording method the method for forming images by four-time scans as in Figs. 5A and 5B described for the first embodiment. Also, as the recording example of images, those represented in Fig. 6 are recorded. Also, the fundamental structures of the recording apparatus, recording head, and others are the same as those adopted for the previous embodiment. Fig. 20 is a structural block diagram which shows the principal part of the printing apparatus as a fifth embodiment in accordance with the present invention. In Fig. 20, the same reference marks are applied to the same constituents as those appearing in Fig. 1 and Fig. 17. The description thereof will be omitted. In Fig. 20, a reference numeral 109 designates operational circuits which correspond to each of the discharge ports one to one. Here, #1, #2, ..., #128 indicated at 109 designate the discharge port numbers 1, 2, ..., 128, respectively. Fig. 21A, Fig. 21B, Fig. 21C, and Fig. 21D are views which illustrate the processing circuits forming the principal part of the operational circuits 109. Fig. 21A shows the processing circuit corresponding to each of the discharge port number 1 to 32; likewise, Fig. 21B, discharge port numbers 33 to 64; Fig. 21C, discharge port numbers 65 to 96; and Fig. 21D, discharge port numbers 97 to 128, respectively. At first, in Fig. 21A, a reference numeral 311 designates a counter, which is increased by 1 per input of one-bit data DI. The counter outputs two-bit data (0, 0), (0, 1), (1, 0), and (1, 1) as SO from QA and QB sequentially and repeatedly. In other words, whenever the data DI becomes "1", the output SO repeats the state of "0", "1", "2", and "3". When the data DI is "0", the output SO does not change. A reference numeral 312A designates a decoder. The output from the decoder 312A and the data DI are input into an AND gate 113. The AND thereof becomes the drive data DO for the head 1. The processing circuits shown in Fig. 21B, Fig. 21C, and Fig. 21D are structured, in which the decoder 312A shown in Fig. 21A is replaced with decoders 312B, 312C, and 312D, respectively, thus being arranged to differentiate the outputs of the decoders depending on the outputs of the counter 311. The outputs SO from the counter 311 shown in Figs. 21A, 21B, 21C, and 21D change sequentially in accordance with the line numbers as shown in Fig. 4 at each time of the first, second, third, and fourth scans as shown in Figs. 5A and 5B. As regards the pixel arrays 1001, 1002, 1003, and 1004 at the time of first scan shown in Fig. 3A, for example, the outputs from the counters 311 corresponding thereto are "0", "0", "0", "0" before recording the line number 1, but before recording the next line number 2, the counters for arrays 1001, 1003 and 1004, but not 1002, are increased, to change their outputs to "1", ''0", "1" "1" in accordance with the data DI to be described later. In other words, the processing circuits shown in Figs. 21A to 21D execute the same processes as shown in Figs. 14A to 14D, and the outputs SO sequentially repeat the state "0", "1", "2", "3" whenever "1" is inputted as the data DI as described above. If the data DI is "0", no change takes place. Also, the SI corresponds to the output SO before the data DI is inputted. Therefore, in accordance with the present embodiment, it is possible to record the image shown in Fig. 6 by dividing scans into four times, while updating the nozzle context as in the first embodiment described above. (Sixth Embodiment) Now, the detailed description will be made of a sixth embodiment in accordance with the present invention. The present embodiment adopts the recording method that divides scans into two as shown in Figs. 9A and 9B described for the second embodiment, and records the image shown in Fig. 6 as the example of image to be recorded by the present embodiment. The principal parts of the printing apparatus to which the present embodiment is applicable are structured the same as those shown in Fig. 20 described for the fifth embodiment. However, the operational circuits 109, that are provided one to one for each discharge port, are structured as in Figs. 22A and 22B. Fig. 22A shows the processing circuits in the operation circuit 109, which correspond to discharge port numbers 1 to 64, and Fig. 22B shows the processing circuits that correspond to the discharge port numbers 65 to 128. At first, in Fig. 22A, reference marks 321A, 3218 and 321C designates D-type flip-flops, which receive SIO, SI1, and SI2 as its input and output SO0, SO1, and SO2, respectively. The outputs SI0, SI1, and SI2 form 3-bit inputs SI as in the second embodiment described above. Also, the inputs SO0, SO1, and SO2 form the outputs SO as in the second embodiment described above. Also, a reference numeral 322 designates an AND circuit and 323, and exclusive OR circuit. The processing circuit shown in Fig. 22B is of such a structure that a NOT circuit 324 is further provided in addition to the circuit shown in Fig. 22A. In other words, each of the processing circuits shown in Fig. 22A and Fig. 22B is arranged to execute the same processes as shown in Fig. 10A and Fig. 10B, respectively. Therefore, with the structure arranged for the present embodiment, it is possible to record the image shown in Fig. 6 by dividing the scans into two as in the second embodiment, while updating the nozzle context. (Other Embodiments) Now, for each of the embodiments, first to fourth, described above, only one operational circuit 106 is provided, but it may be possible to arrange it in plural numbers in order to allow the numbers of the operational circuits and discharge ports to correspond one to one. With this arrangement, it becomes unnecessary to provide the selectors 113 and 123 shown in Fig. 4 and Fig. 12, respectively. Also, in accordance with the first embodiment, the nozzle context memory 105 is reset to "0" before starting each scan. It is not necessarily reset to "0". It should be good enough if only the nozzle context memory 105, which corresponds to the discharge ports used for recording on one and the same pixel array, is set at the same value. Also, in the first embodiment, it may be possible to obtain the same result by enabling the operational circuit 106 to make its outputs as shown in Fig. 14D for all the discharge port numbers #1 to 128 by making an arrangement so that before starting each scan, the nozzle context memory 105 is reset to "0" for the discharge port numbers #97, 98, 99, and 100; the nozzle context memory 105 is set at "3" for the discharge port numbers #65, 66, 67, and 68; the nozzle context memory 105 is set at "2" for the discharge port numbers #33, 34, 35, and 36; and the nozzle context memory 105 is set at "1" for the discharge port numbers #1, 2, 3, and 4. With the structure thus arranged, it also becomes unnecessary to provide the selector 113. Further, in accordance with each embodiment described above, only one recording head 1 is adopted, but it is of course possible to arrange the structure so that a color ink jet recording apparatus is adopted with the provision of plural heads. Also, in each of the embodiments described above, the data stored on the output buffer 102 are defined as the binary data that indicate discharge / non-discharge of ink. However, it may be possible to arrange the structure so that, while preparing the image data handled by the recording apparatus itself to be applicable to the multiply valued images, the output buffer 102 stores the binary data, which are treated by the known binarization process such as dither method, error diffusion method, among some others. Here, particularly among ink jet recording methods, the present invention may be used advantageously with a recording head and a recording apparatus of a method where thermal energy generating means (electrothermal transducing elements, laser beam, or the like, for example) is provided for generating energy to be utilized for discharging ink, and ink is caused to change its states by the application of such thermal energy, because a method of the kind makes it possible to attain recording in high density and high precision. Regarding the typical structure and operational principle of such method, it is preferable to adopt those which can be implemented using the fundamental principle disclosed in US-A-4,723,129 and US-A-4,740,796, for example. This method is applicable to the systems of the so-called on-demand type and a continuous type. Particularly, however, the method is suitable for the on-demand type because the principle is such that at least one driving signal, which provides a rapid temperature rise beyond nucleation boiling point in response to recording information, is applicable to an electrothermal transducing element disposed on a liquid (ink) retaining sheet or liquid path thereby to cause the electrothermal transducing element to generate thermal energy to produce film boiling on the thermoactive portion of recording means (recording head), thus effectively leading to the resultant formation of a bubble in the recording liquid (ink) one to one in response to each of the driving signals. By the development and contraction of the bubble, the liquid (ink) is discharged through a discharge port to produce at least one droplet. The driving signal is more preferably in the form of pulses because the development and contraction of the bubble can be effectuated instantaneously and appropriately. Therefore, the liquid (ink) is discharged with quicker response. The driving signal in the form of pulses is preferably such as disclosed in US-A-4,463,359 and US-A-4,345,262. In this respect, the temperature increasing rate of the thermoactive surface is preferably such as disclosed in US-A-4,313,124 for an excellent recording in a better condition. The structure of the recording head may be as shown in each of the above-mentioned specifications wherein the structure is arranged to combine the discharging ports, liquid paths, and the electrothermal transducing elements (linear type liquid paths or right-angled liquid paths). Besides, the structure, such as disclosed in US-A-4,558,333 and US-A-4,459,600 wherein the thermal activation portions are arranged in a curved area, may also be used in the present invention. In addition, the present invention may be applied to the structure disclosed in JP-A-59-123670 wherein a common slit is used as the discharging ports for plural electrothermal transducers, and to the structure disclosed in JP-A-59-138461 wherein an aperture for absorbing pressure wave of the thermal energy is formed corresponding to the discharge ports. In other words, it is possible to perform recording reliably and more effectively in accordance with the present invention irrespective of the modes of recording heads. Also, with respect to the third and fourth embodiments of those described above, the present invention is effectively applicable to the recording head of a full-line type having a length corresponding to the maximum width of a recording medium recordable by the recording apparatus. For such recording head, it may be possible to adopt either a structure whereby the required length is provided by combining a plurality of recording heads or a structure in which one recording head is integrally formed. In addition, the present invention may be applied not only to the serial type as described above, but also, applicable to a recording head fixed to an apparatus main body; a recording head of an exchangeable chip type, which is made operative when electrically connected with an apparatus main body, and receiving ink supply therefrom when mounted on an apparatus main body; or a recording head of a cartridge type where an ink tank is integrally formed with the recording head itself. Also, for the present invention, it is preferable to additionally provide a recording head with recovery means and preliminarily auxiliary means as constituents of the recording apparatus because these additional means will contribute to making the effectiveness of the present invention more stabilized. To name them specifically, these are capping means, cleaning means, suction or compression means, preheating means such as electrothermal transducing elements or heating elements other than such transducing elements or the combination of those types of elements, and a predischarge means for performing discharge other than the regular discharge for the recording head. Also, regarding the kinds and numbers of ink jet recording heads to be mounted, the present invention is not only applicable to a recording mode in which only one recording head is provided for use of one monochromic ink, but also to an apparatus having plural recording heads provided for use of plural kinds of ink in different colors or in densities. In other words, the present invention may be applied to an apparatus provided with at least one of various recording modes using a multi-color of different colors or a full-color of mixed colors, irrespective of whether the recording heads are integrally structured or it is structured by a combination of plural recording heads. Furthermore, for the embodiments of the present invention described above, ink has been described as liquid. However, ink may be an ink material which is solidified below the room temperature but soften or liquefied at the room temperature, or for the ink jet method, since ink is generally controlled within the temperature not lower than 30°C and not higher than 70°C in order to stabilize its viscosity for the execution of stable discharges, the ink may be such as to be liquefied when the required recording signals are applied. In addition, while positively preventing the temperature rise due to the thermal energy by use of such energy as an energy to be consumed for changing states of ink from solid to liquid, or by use of the ink which will be solidified when left intact for the purpose of preventing the ink from being evaporated, it may be possible to adopt for the present invention the use of an ink having a nature of being liquefied only by the application of thermal energy, such as ink capable of being discharged as ink liquid by enabling itself to be liquefied anyway when the thermal energy is given in accordance with recording signals, and also, a kind of ink that will have already begun solidifying itself by the time it reaches a recording medium. In such a case, it may be possible to retain ink in the form of liquid or solid in the recesses or through holes of a porous sheet such as disclosed in JP-A-54-56847 or JP-A-60-71260 in order to keep such ink to face the electrothermal transducing elements. In the present invention, the most effective method applicable to various kinds of ink mentioned above is the one capable of implementing the film boiling method as described above. Moreover, as the mode of the recording apparatus of the present invention, it may be possible to adopt a copying apparatus combined with a reader or the like, in addition to the image output terminal for a computer or other information processing apparatus. Also, it may be possible to adopt a mode of a facsimile equipment having transmitting and receiving functions, among some others. Fig. 23 is a block diagram which schematically shows the structure when the recording apparatus of the present invention is made applicable to an information processing apparatus provided with functions as a word processor, a personal computer, a facsimile equipment, and a copying apparatus. In Fig. 23, a reference numeral 1801 designates a controller that controls the systems as a whole, which is provided with a CPU of a microprocessor type or the like and various I/O ports in order to output control signals and data signals to each unit, and to receive control and data signals from each unit, thus executing controls as required; 1802, a display unit to indicate various menus, document information, image data read out by a image reader 1807, and some others on its display screen; and 1803, a transparent pressure-sensitive touch panel installed on the display unit 1802, which enables items and coordinate positions to be inputted through the display unit when the surface thereof is depressed by use of a finger or the like accordingly. A reference numeral 1804 designates an FM (Frequency Modulation) sound generating unit that stores musical information prepared by a musical editor or the like on a memory unit 1810 or an external memory device 1812 as digital data, and then, reads them out from the memory to execute the FM modulation thereof. The electric signals from the FM sound generating unit 1804 is converted to audible sounds by means of a speaker unit 1805. The printer unit 1806 is the one to which the apparatus of the present invention is applicable, and functions as output terminals of a word processor, a personal computer, a facsimile equipment, and a copying apparatus. A reference numeral 1807 designates an image reader unit arranged on the carrier path in order to read out data on a source document photoelectrically for input. This unit reads source documents not only for facsimile and copying operations, but also, reads various other documents; 1808, the transmission and reception unit of a facsimile (FAX) equipment that transmits data on source documents read out by the image reader unit 1807 for facsimile operation, and receives facsimile signals being transmitted and demodulates them. This unit has an interface function with external devices. A reference numeral 1809 designates a telephone unit provided with the usual telephone, answering telephone, and various other related functions. A reference numeral 1810 designates a memory unit that includes a ROM storing a system program, a manager program, and other application programs together with character fonts, dictionaries, and the like, a RAM to store application program and document information loaded from the external memory devices, and a video RAM. A reference numeral 1811 designates a keyboard unit to input document information, various commands, and the like. The external memory device 1812 uses a floppy disc, a hard disc, or the like as storage medium to store document information, music or voice information, user application programs, and others. Fig. 24 is a view which schematically shows the information processing apparatus represented in Fig. 23. In Fig. 24, a reference numeral 1901 designates a flat panel display that utilizes liquid crystal and others and displays various menus, graphic information, document information, and the like. On the display 1901, a touch panel 1803 is installed, which enables coordinates and items to be inputted when its surface is being depressed by use of a finger or the like as required. A reference numeral 1902 designates a hand set to be used when the apparatus functions as a telephone. The keyboard 1903 is detachably connected with the apparatus main body by means of a cord to input various document information and various data. Also, for the keyboard 1903, various functional keys and others are provided. A reference numeral 1905 designates a floppy disc insertion inlet for the external memory device 1812. A reference numeral 1906 designates a sheet stacking unit to stack source documents to be read out by means of the image reader unit 1807. The source documents are delivered to the rear portion of the apparatus after reading. Also, for the facsimile reception or the like, the received data are printed by use of the ink jet printer 1907. In this respect, the display unit 1802 may be a CRT, but it is preferable to use the flat panel of a liquid crystal display type that utilizes ferroelectric liquid crystal. With such display unit, the apparatus can be made smaller and thinner. When the information processing apparatus described above is made to function as a personal computer or a word processor, each kind of information inputted through the keyboard unit 1811 is processed by the controlling unit 1801 in accordance with a given program, and is output to the printer unit 1806 as images. When the apparatus is made to function as the receiver of a facsimile equipment, the facsimile information, which are received from the FAX transmission and reception unit 1808 through a communication line, are received and processed by the controlling unit 1801 in accordance with a given program, and output to the printer unit 1806 as reception images. Also, when the apparatus is made to function as a copying apparatus, a source document is read by the image reader unit 1807, and the data on the source document thus read are output to the printer unit 1806 through the controlling unit 1801 as copied images. In this respect, when the apparatus is made to function as the transmitter of a facsimile equipment, the data on a source document read by the image reader unit 1807 are transmitted to a communication line through the FAX transmission and reception unit 1808 after being processed by the controlling unit 1801 for transmission in accordance with a given program. Here, as shown in Fig. 25, the information processing apparatus described above may be of an integrated type that incorporates an ink jet printer in it. In such case, the portability of the apparatus is further enhanced. In Fig. 25, the corresponding reference marks are applied to those parts where the apparatus has the same functions as those referred to in Fig. 24. Now, by applying the recording apparatus of the present embodiments to the multi-functional information processing apparatus that has been described above, it is possible to obtain high-quality images recorded at higher speeds with a lesser amount of noises, and to further enhance the functions of such information processing apparatus accordingly. As described above, in accordance with the present embodiments, it is possible to obtain good images by the uniform use of plural discharge ports, and at the same time, to make the capacity of memory smaller for the storage of data to control the plural discharge ports by use of the control data to assign pixels to be formed to the plural discharge ports, and by the calculation of the drive data to control discharge or non-discharge of ink from such plural discharge ports, while updating such control data sequentially. Also, by processing the control data with respect to the edge portions of images, it is possible to obtain good images by use of the so-called draft mode.

Claims: Data generating apparatus, for recording apparatus arranged to record an image using a recording head having a plurality of recording elements, for generating drive data (DO) indicating recording/non-recording by each of the recording elements of the recording head in accordance with image data for the image to be recorded, the data generating apparatus comprising: image memory means (102) for storing the image data; and calculating means (106) for creating the drive data, in respect of any particular recording element, in accordance with elements of said image data which data elements correspond to that particular recording element, characterised in that the data generating apparatus further comprises context memory means (105) for storing context data, corresponding to each recording element, for controlling the recording/non-recording of said elements of image data corresponding to the respective recording element, and the calculating means (106) is arranged to perform, during recording of an image for which image data is stored in the image memory means (102), (a) creation of an element of drive data (DO), in respect of a recording element of the recording head, in accordance with an image data element (DI) corresponding to the recording element and the context data (SI) corresponding to the recording element, and (b) updating of the context data in accordance with the image data element to form updated context data (SO) corresponding to the recording element for use with a subsequent image data element corresponding to the recording element. Apparatus according to claim 1, comprising edge detecting means (211,212) for detecting edge portions in the image for which image data is stored in the image memory means (102), and for resetting the context data corresponding to the edge portions in accordance with the detection of the edge portions. Apparatus according to claim 2 in which the edge detecting means is arranged to detect transitions in the image data (DI), from data indicating non-recording to data indicating recording, as edge portions. Apparatus according to claim 2 in which the edge detecting means is arranged to detect transitions in the image data (DI), from data indicating recording to data indicating non-recording, as edge portions. Apparatus according to claim 2 in which the edge detecting means is arranged to detect transitions in the image data (DI) from data indicating non-recording to data indicating recording, and transitions in the image data (DI) from data indicating recording to data indicating non-recording, as edge portions. Apparatus according to any one of the preceding claims in which the calculating means (106) is arranged to perform the said updating of the context data each time it performs the said creation of an element of drive data. Apparatus according to any one of the preceding claims, for use with recording apparatus arranged to scan the recording head over an area of a recording medium during recording of an image for which image data is stored in the image memory means (102). Apparatus according to claim 7, for use with recording apparatus arranged to scan the recording head a plurality of times over an area of a recording medium for printing onto the area during recording of an image for which image data is stored in the image memory means (102), the calculating means (106) being arranged to perform operations (a) and (b) during each scan over the area. Apparatus according to claim 8 which is arranged to provide, for each scan over the same area, the same initial values of the context data in respect of the recording elements corresponding to the same image data elements (DI). Apparatus according to claim 8 which is arranged to provide, for each respective scan over the same area, different respective initial values of the context data in respect of the recording elements corresponding to the same image data elements (DI). Apparatus according to any one of claims 1 to 9 in which the calculating means (106) is arranged to perform creation of an element of drive data (DO) according to a selected one of a plurality of modes of drive data creation, and is arranged to select the mode of drive data creation in accordance with the recording element to which the drive data element corresponds. Apparatus according to any one of claims 1 to 8 and 10 which is arranged to provide, for the context data corresponding to a recording element, an initial value selected from a plurality of values, and is arranged to select the initial value in accordance with the recording element to which the context data corresponds. Recording apparatus, for recording an image using a recording head having a plurality of recording elements, the apparatus comprising: data generating apparatus according to any one of claims 7 to 10; scanning means (2,3) for scanning the recording head relative to the recording medium; and head driving means (107,108) for driving the recording elements of the recording head in accordance with the drive data (DO). Recording apparatus according to claim 13, further comprising: conveying means (4,5) for conveying the recording medium relative to the recording head in a direction transverse to the scanning direction of the scanning means (2,3); and control means for making the distance of relative conveying of the recording medium per scan of the recording head smaller than the extent in the conveyance direction of the image area defined by the drive data generated per scan, and in which the calculating means (106) can be arranged to create drive data (DO) corresponding to the same recording area of the recording medium for printing in a plurality of scans, the drive data generated in respect of different scans of the same recording area complementing one another. Recording apparatus according to claim 14 when claim 13 is dependent on any one of claims 7 to 9 in which the calculating means (106) is arranged to perform creation of an element of drive data (DO) according to a selected one of a plurality of modes of drive data creation, and is arranged to select the mode of drive data creation in accordance with which group of recording elements includes the recording element to which the drive data element belongs, the calculating means being arranged to divide the recording elements into groups in accordance with the number of scans of the same recording area for which the calculating means is arranged to create drive data. Recording apparatus according to any one of claims 13 to 15 when claim 13 is dependent on any one of claims 7 to 9 which is arranged to provide, before a scan of the recording head begins, the same initial values of the context data in respect of all the recording elements. Recording apparatus according to claim 13 or claim 14, when claim 13 is dependent on any one of claims 7, 8 and 10, which is arranged to provide before a scan of the recording head begins, an initial value for the context data corresponding to a recording element selected in accordance with the recording element to which the context data corresponds. Recording apparatus according to any one of claims 13 to 17, fitted with a recording head having a plurality of recording elements, for recording an image according to the drive data generated by the data generating apparatus. A method of generating drive data (DO), for recording apparatus arranged to record an image using a recording head having a plurality of recording elements, the drive data (DO) indicating recording/non-recording by each of the recording elements of the recording head in accordance with image data for the image to be recorded, the data generating method comprising: creating the drive data, in respect of any particular recording element, in accordance with elements of said image data (DI) which data elements correspond to that particular recording element, characterised in that : the method further comprises storing context data, corresponding to each recording element, for controlling the recording/non-recording of said elements of image data corresponding to the respective recording element; and in that during recording of an image in accordance with said image data, (a) an element of drive data (DO), in respect of a recording element of the recording head, is created in accordance with an image data element (DI) corresponding to the recording element and the context data (SI) corresponding to the recording element, and (b) the context data is updated in accordance with the image data element to form updated context data (SO) corresponding to the recording element for use with a subsequent image data element corresponding to the recording element. A method according to claim 19 comprising detecting edge portions in the image corresponding to the said image data, and resetting the context data corresponding to the edge portions in accordance with the detection of the edge portions. A method according to claim 20 in which the edge detecting step comprises detecting transitions in the image data (DI), from data indicating non-recording to data indicating recording, as edge portions. A method according to claim 20 in which the edge detecting step comprises detecting transitions in the image data (DI), from data indicating recording to data indicating non-recording, as edge portions. A method according to claim 20 in which the edge detecting step comprises detecting transitions in the image data (DI) from data indicating non-recording to data indicating recording, and transitions in the image data (DI) from data indicating recording to data indicating non-recording, as edge portions. A method according to any one of claims 19 to 23 in which the said step of updating the context data is performed each time the said step of creation of an element of drive data is performed. A method of generating drive data (DO) according to any one of claims 19 to 24 for recording apparatus arranged to scan the recording head a plurality of times over an area of a recording medium for printing onto the area during recording of an image for which image data is stored in the image memory means (102), the method comprising performing operations (a) and (b) during each scan over the area. A method according to claim 25 in which, for each scan over the same area, the same initial values of the context data are provided in respect of the recording elements corresponding to the same image data elements (DI). A method according to claim 25 in which, for each respective scan over the same area, different respective initial values of the context data are provided in respect of the recording elements corresponding to the same image data elements (DI). A method according to any one of claims 19 to 26 in which the creation of an element of drive data (DO) is performed according to a selected one of a plurality of modes of drive data creation, and the mode of drive data creation is selected in accordance with the recording element to which the drive data element corresponds. A method according to any one of claims 19 to 25 and 27 which comprises providing, for the context data corresponding to a recording element, an initial value selected from a plurality of values, the initial value being selected in accordance with the recording element to which the context data corresponds. A method of recording an image with a recording apparatus using a recording head provided with a plurality of recording elements, comprising forming pixels on a recording medium in accordance with drive data generated in a method according to any one of claims 19 to 29.

Inventors: HYOTANI HIROYUKI, KASAMATSU TAKEHIKO, TAKAGI SHINJI, TANAKA HIDEKI, HYOTANI, HIROYUKI, KASAMATSU, TAKEHIKO, TAKAGI, SHINJI, TANAKA, HIDEKI
Applicants: CANON KK, CANON KABUSHIKI KAISHA
Application year: 1997
Main classification: G06K15
IPC codes: G06K15, B41J2