Patent Publication Number: US-2003222931-A1

Title: Method of and apparatus for managing nozzle of ink-jet printer

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001] This application claims the benefit of Korean Patent Application No. 2002-31292, filed Jun. 4, 2002, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002] 1. Field of the Invention  
       [0003] The present invention relates to an ink-jet printer, and more particularly, to a method of and an apparatus for managing a nozzle in an ink-jet printer.  
       [0004] 2. Description of the Related Art  
       [0005] A head in an ink-jet printer has a plurality of nozzles. Here, each nozzle is driven in response to a nozzle drive signal, and thus ink is ejected through the nozzle. In this case, a printing quality of the ink-jet printer depends on whether each nozzle operates normally. For example, when the nozzle is clogged because the nozzle has not been used for a long time, or the when the ink is continuously ejected through the nozzle regardless of a special management taken by the ink-jet printer, and thus the ink of different colors are mixed together. As a result, the printing quality is lowered. To prevent the printing quality from being lowered, the ink-jet printer must perform operations of managing the nozzle before or during printing.  
       [0006] Hereinafter, a conventional method for managing a nozzle of an ink-jet printer will be described.  
       [0007] First, when power is applied to the ink-jet printer, a new head is installed in the ink-jet printer, or a predetermined amount of time has passed from a previous printing time when the ink-jet printer performed any operation, managing operations of wiping a nozzle once and ejecting ink through the nozzle an appropriate number of times is repeated twice, and then, the nozzle can be capped. In addition, when the managing operations of the nozzle are instructed by a user, for example, when it is determined by the user that a printing quality is not good enough or that the nozzle needs to be managed, the managing operations of wiping a nozzle once and ejecting ink through the nozzle an appropriate number of times can be repeated three times. Further, the managing operations of wiping the nozzle once and ejecting ink through the nozzle an appropriate number of times can be performed once before each page of a document is printed. Furthermore, the managing operations of wiping a nozzle once and ejecting ink through the nozzle an appropriate number of times can be performed after a predetermined number of lines are printed during printing the document.  
       [0008] In the above-mentioned conventional method of managing the nozzle of the ink-jet printer, the nozzle is managed only depending on the number of lines printed, regardless how much ink is ejected while the document is printed. Hence, in the conventional method of managing the nozzle of the ink-jet printer, the managing operations of managing the nozzle are not performed when the nozzle really needs to be managed, and the managing operations of managing the nozzle are unnecessarily performed when the nozzle does not need to be managed. Thus, the conventional method of managing the nozzle of the ink-jet printer cannot provide a uniform printing quality.  
       SUMMARY OF THE INVENTION  
       [0009] To solve the above and the other problems, it is an aspect of the present invention to provide a method of managing a nozzle of an ink-jet printer in response to an amount of ink actually ejected and an ejection time during which the ink is ejected through the nozzle.  
       [0010] It is another aspect of the present invention to provide an apparatus for managing a nozzle of an ink-jet printer in response to an amount of ink actually ejected and an ejection time during which the ink is ejected through the nozzle.  
       [0011] Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.  
       [0012] Accordingly, to achieve the above and/or other aspects, there is provided a method of managing a nozzle of an ink-jet printer. The method comprises determining whether an operation of printing a document is requested, counting slices of print data if it is determined that the operation of printing the document is requested, determining whether a counting result of counting the slices is larger than a first predetermined value, performing the counting of the slices if it is determined that the counting result is not larger than the first predetermined value, managing the nozzle if it is determined that the counting result is larger than the first predetermined value, determining whether the operation of printing the document is terminated, and performing the counting of the slices if it is determined that the operation of printing the document is not terminated.  
       [0013] In order to achieve the above and/or other aspects, there is provided an apparatus for managing a nozzle of an ink-jet printer. The apparatus includes a print request checking unit which checks whether an operation of printing a document is requested and outputs a checking result of checking the operation of printing document as a first control signal when the operation of printing the document is requested, a counter which counts slices of print data in response to the first control signal and outputs a counting result, a comparator which compares the counting result received from the counter with a first predetermined value and outputs a result of the comparison as a second control signal, a nozzle managing unit which manages the nozzle in response to the second control signal, and a print termination checking unit which checks whether the operation of printing the document is terminated and outputs a checking result as a third control signal. The counter counts the slices of the print data in response to the first control signal, the second control signal, and the third control signal and outputs the counting result. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0014] The above and/or the other aspects and advantages of the present invention will become more apparent and more readily appreciated from the following description of preferred embodiments, taken in conjunction with the accompanying drawings of which:  
     [0015]FIG. 1 is a flowchart illustrating a method of managing a nozzle of an ink-jet printer according to an embodiment of the present invention;  
     [0016]FIG. 2 is a flowchart illustrating a method of managing a nozzle of an ink-jet printer according to another embodiment of the present invention;  
     [0017]FIG. 3 is a flowchart illustrating a method of managing a nozzle of an ink-jet printer according to another embodiment of the present invention;  
     [0018]FIG. 4 is a block diagram illustrating an apparatus for managing a nozzle of an ink-jet printer using the methods shown in FIG. 1;  
     [0019]FIG. 5 is a block diagram illustrating an apparatus for managing a nozzle of an ink-jet printer using the method shown in FIGS. 1 and 2; and  
     [0020]FIG. 6 is a block diagram illustrating an apparatus for managing a nozzle of an ink-jet printer using the method shown in FIGS. 1 and 3.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0021] Reference will now be made in detail to the present preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described in order to explain the present invention by referring to the figures.  
     [0022] The present invention will be described more fully hereinafter with reference to the accompanying drawings in which preferred embodiments of the invention are shown.  
     [0023]FIG. 1 is a flowchart illustrating a method of managing a nozzle of an ink-jet printer according to an embodiment of the present invention. The flowchart shown in FIG. 1 comprises obtaining an amount of ink ejection when a document needs to be printed in operations  10  and  12  and maintaining a nozzle according to a result of comparing the amount of the ink ejection with a first predetermined value in operations  14  through  18 .  
     [0024] In operation  10 , it is determined whether the document needs to be printed. If it is determined that the document needs to be printed, slices of print data are counted in operation  12 . Here, the print data includes a number of slices, each slice has several bits, and each bit is used to enable ink to be ejected through each nozzle. For example, the print data may be generated by a personal computer (PC) (not shown) and transmitted to the ink-jet printer.  
     [0025] According to the embodiment of the present invention, in operation  14  after operation  12 , it is determined whether the amount of the ink ejection, that is, a counting result of counting of the slices of the print data, is larger than the first predetermined value. Here, the first predetermined value is empirically obtained. If it is determined that the counting result, that is, the amount of the ink ejection, is not larger than the first predetermined value, the counting of the slices of the print data continues. However, if it is determined that the counting result, that is, the amount of the ink ejection, is larger than the first predetermined value, in operation  16 , the nozzle is managed. Here, if it is determined that the counting result, that is, the amount of the ink ejection, is larger than the first predetermined value, at least one of an operation of wiping the nozzle, an operation of ejecting ink through the nozzle, and an operation of capping the nozzle can be performed. For example, if it is determined that the counting result, that is, the amount of the ink ejection, is larger than the first predetermined value, operations of wiping the nozzle once and ejecting ink through the nozzle x times (where x is a predetermined number) can be performed. In this way, in the method of managing the nozzle of the ink-jet printer according to the present invention, only if the counting result, that is, the amount of the ink ejection, is larger than the first predetermined value, the nozzle is managed regardless of whether an initial part or a middle part of the document is printed.  
     [0026]FIG. 2 is a flowchart illustrating an operation of the method of managing the nozzle of the ink-jet printer according to another embodiment of the present invention. The flowchart shown in FIG. 2 comprises adjusting the counting result of the counting the slices of the print data according to a type of the document in operation  30  and  32 .  
     [0027] The method of managing the nozzle of the ink-jet printer shown in FIG. 1 may further include operations  30  and  32  shown in FIG. 2. In this case, in operation  30  performed after operation  12 , the type of the document is checked. That is, it is checked whether the document to be printed is a text or graphics. In operation  32  performed after operation  30 , the counting result is adjusted according to the checked type of the document, a result of an adjustment of the counting result is determined as the amount of the ink ejection, and then, operation  14  is performed. Thus, in operation  14 , it is determined whether the result of the adjustment of operation  32  corresponding to the amount of the ink ejection is larger than the first predetermined value.  
     [0028] For example, when the type of the document is the text, the counting result is multiplied by a second predetermined value, and a result of the multiplication is determined as the amount of the ink ejection. In addition, when the type of the document is the graphics, the counting result is multiplied by a third predetermined value, and the result of the multiplication is determined as the amount of the ink ejection. In this case, the third predetermined value is set to be larger than the second predetermined value. For example, the second predetermined value may be set to 10, 20 or 30, and the third predetermined value may be set to 40 or 50. However, it is understood that the invention is not limited thereto.  
     [0029]FIG. 3 is a flowchart illustrating another operation of the method of managing the nozzle of the ink-jet printer according to another embodiment of the present invention. The flowchart shown in FIG. 3 comprises adjusting the accounting result according to printing conditions in operations  50  and  52 .  
     [0030] The method of managing the nozzle of the ink-jet printer shown in FIG. 1 may further include operations  50  and  52  of FIG. 3. In this case, in operation  50  performed after operation  12 , the printing conditions of the document, that is, at least one of a speed and a resolution with which the document is printed, is determined. In operation  52 , the counting result is adjusted according to a result of a determination of the printing conditions in operation  50 , the result of an adjustment of the counting result is determined as the amount of the ink ejection, and then, operation  14  is performed. Thus, in operation  14 , it is determined whether the result of the adjustment of operation  52  corresponding to the amount of the ink ejection is larger than the first predetermined value.  
     [0031] For example, when a user wants to print the document with a low resolution at a high speed, the counting result is multiplied by a fourth predetermined value corresponding to the low resolution and the high speed, and the result of the multiplication is determined as the amount of the ink ejection. In addition, when the user wants to print a document with a high resolution at a low speed, the counting result is multiplied by a fifth predetermined value corresponding to the high resolution and the low speed, and the result of the multiplication is determined as the amount of the ink ejection. In this case, the fifth predetermined value is set to be larger than the fourth predetermined value. For example, when the document is the text, the fourth predetermined value may be set to 10, and the fifth predetermined value may be set to 30. When the document is the graphics, the fourth predetermined value may be set to 40, and the fifth predetermined value may be set to 50. However, it is understood that the invention is not limited thereto.  
     [0032] Meanwhile, in operation  18  performed after operation  16 , it is determined whether the operation of printing the document is terminated. If it is determined that the operation of printing the document is not terminated, operation  12  is performed. However, if it is determined that the operation of printing the document is terminated, the method of managing the nozzle of the inkjet printer shown in FIG. 1 is terminated. Thus, the counting result is reset. In this case, the operation of printing the document is performed while operations  12 ,  14 , and  16  shown in FIG. 1 are performed.  
     [0033] Hereinafter, a structure and an operation of an apparatus for managing the nozzle of the ink-jet printer performing the above-mentioned respective methods shown in FIGS. 1 through 3, will be described with reference to the accompanying drawings.  
     [0034]FIG. 4 is a block diagram illustrating the apparatus for managing the nozzle of the inkjet printer performing the method shown in FIGS. 1 through 3.  
     [0035] Referring to FIG. 4, the apparatus includes a print request checking unit  70 , a counter  72 , a comparator  74 , a nozzle managing unit  76 , and a print termination checking unit  78 .  
     [0036] In order to perform operation  10  shown in FIG. 1, the print request checking unit  70  checks whether the operation of printing the document is requested and outputs the checking result of checking the printing of the document as a first control signal C 1  to the counter  72 . For example, a personal computer (PC) may generate a print request signal used to request the printing of the document. In this case, the print request checking unit  70  can analyze the print request signal that is received from the PC through an input terminal IN 1  and can check whether the operation of printing the document is requested.  
     [0037] In order to perform operation  12 , the counter  72  counts the slices of the print data that is inputted to an input terminal IN 2 , in response to the first control signal C 1  that is received from the print request checking unit  70 , and the counter  72  outputs the counting result of the counting of the slices to the comparator  74 . For example, if it is recognized through the first control signal C 1 , which is received from the print request checking unit  70 , that the operation of printing the document is requested, the counter  72  counts the slices of the print data inputted to the input terminal IN 2  and outputs the counting result to the comparator  74 .  
     [0038] In order to perform operation  14 , the comparator  74  compares the counting result, that is, the amount of the ink ejection, which is received from the counter  72 , with the first predetermined value and outputs the result of the comparison as a second control signal C 2  to the nozzle managing unit  76  and the counter  72 , respectively. In this case, if it is recognized through the second control signal C 2 , which is received from the comparator  74 , that the amount of the ink ejection is not larger than the first predetermined value, the counter  72  continuously counts the slices of the print data inputted to the input terminal IN 2  and outputs the counting result to the comparator  74 .  
     [0039]FIG. 5 is a block diagram illustrating another apparatus performing the respective methods shown in FIGS. 1 and 2. Referring to FIG. 5, the apparatus for managing the nozzle of the ink-jet printer includes a document type checking unit  90  and a first ink ejection amount adjusting unit  92 .  
     [0040] The apparatus shown in FIG. 4 may further include the document type checking unit  90  and the first ink ejection amount adjusting unit  92 . In this case, in order to perform operation  30 , the document type checking unit  90  shown in FIG. 5 checks the type of the document and outputs the checking result of the checking of the type of the document as a fourth control signal C 4  to the first ink ejection amount adjusting unit  92 . For example, the PC may generate a document type discrimination signal representing the type of the document. In this case, the document type checking unit  90  can analyze the document type discrimination signal that is received from the PC through an input terminal IN 4 , and can check the type of the document to be printed, that is, whether the document to be printed is the text or the graphics, through a result of an analysis of the document type discrimination signal.  
     [0041] In order to perform operation  32 , the first ink ejection amount adjusting unit  92  adjusts the counting result that is inputted to an input terminal IN 5  from the counter  72 , in response to the fourth control signal C 4  that is received from the document type checking unit  90 , and outputs the result of adjustment as the amount of the ink ejection to the comparator  74  shown in FIG. 4 through an output terminal OUT 2 . In this case, the comparator  74  compares the amount of the ink ejection that is received from the first ink ejection amount adjusting unit  92 , with the first predetermined value and outputs the result of the comparison as the second control signal C 2 . For this purpose, the first ink ejection amount adjusting unit  92  may be implemented with first and second multipliers  94  and  96 . Here, the first multiplier  94  multiplies the counting result inputted to the input terminal IN 5 , by the second predetermined value in response to the fourth control signal C 4  that is received from the document type checking unit  90 , and outputs the result of the multiplication as the amount of the ink ejection through the output terminal OUT 2 .  
     [0042] In addition, the second multiplier  96  multiplies the counting result by the third predetermined value in response to the fourth control signal C 4  that is received from the document type checking unit  90 , and outputs the result of the multiplication as the amount of the ink ejection through the output terminal OUT 2 . Here, only one of the first and second multipliers  94  and  96  operates in response to the fourth control signal C 4 . That is, if it is recognized through the fourth control signal C 4  that the type of the document to be printed, is the text, the result of the multiplication in the first multiplier  94  is outputted as the amount of the ink ejection through the output terminal OUT 2 . Also, if it is recognized through the fourth control signal C 4  that the type of the document to be printed is the graphics, the result of the multiplication in the second multiplier  96  is outputted as the amount of the ink ejection through the output terminal OUT 2 . The amount of the ink ejection corresponds to the second control signal to control the nozzle managing unit  76  to perform a combination of the capping operation, the wiping operation, and the ink-ejecting operation.  
     [0043]FIG. 6 is a block diagram illustrating another apparatus performing the method shown in FIGS. 1 and 3 according to another embodiment of the present invention. Referring to FIG. 6, the apparatus for managing the nozzle of the ink-jet printer includes a print condition checking unit  110  and a second ink ejection amount adjusting unit  112 .  
     [0044] The apparatus for managing a nozzle of an ink-jet printer shown in FIG. 4 may further include the print condition checking unit  110  and the second ink ejection amount adjusting unit  112 . In this case, in order to perform operation  50 , the print condition checking unit  110  shown in FIG. 6 determines the printing conditions, that is, at least one of the speed and the resolution with which the document is to be printed, and outputs the result of the determination as the fifth control signal C 5  to the second ink ejection amount adjusting unit  112 . For example, the PC may generate a printing condition discrimination signal representing the printing conditions. In this case, the print condition checking unit  110  can analyze the printing condition discrimination signal that is received from the PC through an input terminal IN 6 , and can check through the result of the analysis of the printing conditions with which the document is to be printed.  
     [0045] In order to perform operation  52 , the second ink ejection adjusting unit  112  adjusts the counting result that is inputted to an input terminal IN 7  from the counter  72  shown in FIG. 4, in response to the fifth control signal C 5  that is received from the print condition checking unit  110 , and outputs the result of the adjustment of the counting result as the amount of the ink ejection to the comparator  74  through an output terminal OUT 3 . In this case, the comparator  74  compares the amount of the ink ejection that is received from the second ink ejection amount adjusting unit  112 , with the first predetermined value, and outputs the result of the comparison as the second control signal C 2 . For this purpose, the second ink ejection amount adjusting unit  92  may be implemented with third and fourth multipliers  114  and  116 . Here, the third multiplier  114  multiplies the counting result that is inputted from the counter  72  through an input terminal IN 7 , by a fourth predetermined value in response to the fifth control signal C 5  that is received from the print condition checking unit  110 , and outputs the result of the multiplication as the amount of the ink ejection through an output terminal OUT 3  to the comparator  74 .  
     [0046] In addition, the fourth multiplier  116  multiplies the counting result that is inputted through the input terminal IN 7  from the counter  72 , by a fifth predetermined value in response to the fifth control signal C 5  that is received from the print condition checking unit  110 , and outputs to the comparator  74  the result of the multiplication as the amount of the ink ejection through the output terminal OUT 3 . Here, only one of the third and fourth multipliers  114  and  116  operates in response to the fifth control signal C 5 . For example, if it is recognized through the fifth control signal C 5  that the document is printed at the high speed with the low resolution, the result of the multiplication in the third multiplier  114  is outputted as the amount of the ink ejection through the output terminal OUT 3 . Also, if it is recognized through the fifth control signal C 5  that the document is printed at the low speed and with the high resolution, the result of the multiplication in the fourth multiplier  116  is outputted as the amount of the ink ejection through the output terminal OUT 3 .  
     [0047] Meanwhile, in order to perform operation  16 , the nozzle managing unit  76  manages the nozzle in response to the second control signal C 2  that is received from the comparator  74 . For example, the nozzle managing unit  76  manages the nozzle if it is recognized through the second control signal C 2 , which is received form the comparator  74 , that the amount of the ink ejection is larger than the first predetermined value. For example, the nozzle managing unit  76  can output at least one of a wiping drive signal, a spitting drive signal, and a capping drive signal simultaneously or sequentially through the output terminal OUT 1 . In this case, a wiping unit (not shown) can perform the operation of wiping the nozzle in response to the wiping drive signal, a spitting unit (not shown) can eject ink through the nozzle in response to the spitting drive signal, and a capping unit (not shown) can cap the nozzle in response to the capping drive signal.  
     [0048] Meanwhile, in order to perform operation  18 , the print termination checking unit  78  checks whether the operation of printing the document is terminated, and outputs the checking result as the third control signal C 3  to the counter  72 . For example, the PC may generate a print termination signal representing an end of the operation of printing the document. In this case, the print termination checking unit  78  can analyze the print termination signal that is received form the PC through the input terminal IN 3 , and can check the termination of the operation of printing the document through the result of the analysis. In this case, if it is recognized through the third control signal C 3 , which is received from the print termination checking unit  78 , that the operation of printing the document is not terminated, the counter  72  continuously counts the slices of the print data that is inputted to the input terminal IN 2 , and outputs the counting result to the comparator  74 .  
     [0049] As described above, the method of and apparatus for managing a nozzle of an ink-jet printer according to the present invention can effectively manage the nozzle in response to the amount of ink that is actually ejected, and a print time, unlike the related art which periodically manages the nozzle at a predetermined time interval while the document is printed. That is, the method of and apparatus for managing the nozzle of the ink-jet printer according to the present invention can effectively manage the nozzle without performing operations of managing the nozzle when the amount of the ink ejection is small, and by performing the operations of managing the nozzle when the amount of the ink ejection is large even though several lines are printed, thereby improving a printing quality.  
     [0050] While this invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and equivalents thereof.