Patent Publication Number: US-11642882-B2

Title: Liquid ejection apparatus and data transmission method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2020-148289, filed on Sep. 3, 2020. The contents of which are incorporated herein by reference in their entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a liquid ejection apparatus and a data transmission method. 
     2. Description of the Related Art 
     There is a technique of performing error detection on data to be transferred to an inkjet head in an inkjet printer (liquid ejection apparatus). 
     A technique of adding check data for error detection (error detection code) to data to be transferred and performing error detection has been disclosed as such inkjet printers for performing error detection (for example, Japanese Patent No. 6487770). 
     According to a conventional technique, however, error detection on image data is performed on a nozzle array basis and, in general, error detection is performed using check data for error detection that is added to the end of image data and there is a problem in that, even when data is transmitted to a head drive device after all data is received and error detection is performed, it is not possible to send all the data completely until a latch signal for the next image data and thus it is not possible to increase the printing speed. 
     SUMMARY OF THE INVENTION 
     According to ab aspect of the present invention, a liquid ejection apparatus includes a transmission-side control device and a reception-side control device. The transmission-side control device is configured to transmit image data to an ejection head. The reception-side control device is configured to transmit data obtained by processing the image data received from the transmission-side control device, to a drive device configured to control a drive element. The transmission-side control device includes a divider, an adder, and a first transmitter. The divider is configured to divide the image data into a plurality of division data. The adder is configured to add check data for error detection to each of the plurality of division data divided by the divider. The first transmitter is configured to transmit, to the reception-side control device, each of the plurality of division data to which the adder adds respective check data. The reception-side control device includes a receiver, an error detector, and a second transmitter. The receiver is configured to receive each of the plurality of division data that are transmitted from the first transmitter, and to which the respective check data are added. The error detector is configured to perform error detection on each of the plurality of division data received by the receiver, using check data added to the division data. The second transmitter is configured to transmit, to the drive device, division data on which a process of error detection is performed by the error detector, in parallel with a process of transmitting division data by the first transmitter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a diagram illustrating a general configuration of a printing system according to an embodiment; 
         FIG.  2    is a diagram illustrating an example of a hardware configuration of an image forming apparatus according to the embodiment; 
         FIG.  3    is a diagram illustrating an example of a hardware configuration of a DFE according to the embodiment; 
         FIG.  4    is a diagram illustrating a hardware configuration of a client PC according to the embodiment; 
         FIG.  5    is a diagram illustrating an example of a schematic configuration of an image forming apparatus according to the embodiment; 
         FIG.  6    is a diagram illustrating an example of configurations of a control board and an inkjet head of the image forming apparatus according to the embodiment; 
         FIG.  7    is a diagram illustrating an example of a timing chart of data transmission and reception in a conventional image forming apparatus; 
         FIG.  8    is a diagram illustrating an example of a timing chart in the case where latch signals have short intervals in the conventional image forming apparatus; 
         FIG.  9    is a diagram illustrating an example of a timing chart of data transmission and reception in the image forming apparatus according to the embodiment; and 
         FIG.  10    is a diagram illustrating an example of a timing chart of data transmission and reception in the case where data is transmitted as a substitute in the image forming apparatus according to the embodiment. 
     
    
    
     The accompanying drawings are intended to depict exemplary embodiments of the present invention and should not be interpreted to limit the scope thereof. Identical or similar reference numerals designate identical or similar components throughout the various drawings. 
     DESCRIPTION OF THE EMBODIMENTS 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present invention. 
     As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
     In describing preferred embodiments illustrated in the drawings, specific terminology may be employed for the sake of clarity. However, the disclosure of this patent specification is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that have the same function, operate in a similar manner, and achieve a similar result. 
     An embodiment of the present invention will be described in detail below with reference to the drawings. 
     An embodiment has an object to provide a liquid ejection apparatus and a data transmission method that make it possible to increase a printing speed while performing error detection on image data to the inkjet head 
     An embodiment of a liquid ejection apparatus and a data transmission method according to the disclosure will be describe in detail below with reference to the accompanying drawings. The following embodiment does not limit the disclosure and the components of the following embodiment include ones that can be easily reached by those skilled in the art and ones substantially the same, that is, ones in the scope of equivalence. Furthermore, various omissions, replacements, changes and combinations of components can be made without departing from the scope of the embodiment below. 
     General Configuration of Printing System 
       FIG.  1    is a diagram illustrating a general configuration of a printing system according to the embodiment. With reference to  FIG.  1   , the general configuration of the printing system according to the embodiment will be described. 
     As illustrated in  FIG.  1   , the printing system according to the embodiment includes an image forming apparatus  1 , a digital front end (DFE)  2 , a client personal computer (PC)  3 , and a management server  4  as an example. As illustrated in  FIG.  1   , each device is able to perform mutual data communication via a network N. The network N is, for example, a network that includes a local area network (LAN) or the Internet and that is a wired network, wireless network, or a network of a combination of a wired network and a wireless network. 
     The image forming apparatus  1  is an inkjet printer (liquid ejection apparatus) that performs image formation (printing) on a recording medium by an inkjet system based on drawing data (image data) that is received from the DFE  2 . A specific hardware configuration and a specific mechanical schematic configuration of the image forming apparatus  1  will be descried below using  FIG.  2    and  FIG.  5   . 
     The DFE  2  is an information processing device that receives a printing job from the client PC  3  or the management server  4 , prepares drawing data based on the printing job by a raster image processor (RIP) engine, and transmits the drawing data to the image forming apparatus  1 . A specific hardware configuration of the DFE  2  will be described below using  FIG.  3   . 
     The client PC  3  is an information processing device that prepares a printing job that a user wants to print and transmits the printing job to the DFE  2  or the management server  4 . A specific hardware configuration of the client PC  3  will be described below using  FIG.  4   . 
     The management server  4  is a server device that manages the printing job that is received from the client PC  3  and transmits the printing job to the DFE  2  according to a request from the DFE  2 . A specific configuration of the management server  4  will be described below using  FIG.  4   . 
     Hardware Configuration of Image Forming Apparatus 
       FIG.  2    is a diagram illustrating an example of the hardware configuration of the image forming apparatus according to the embodiment. With reference to  FIG.  2   , the hardware configuration of the image forming apparatus  1  according to the embodiment will be described. 
     As illustrated in  FIG.  2   , the image forming apparatus  1  includes a central processing unit (CPU)  501 , a read only memory (ROM)  502 , a random access memory (RAM)  503 , an auxiliary storage device  504 , a network I/F  505 , an image forming unit  506 , and a read unit  507 . 
     The CPU  501  is an arithmetic logic unit that controls the image forming apparatus  1  generally. The ROM  502  is a non-volatile storage device that stores programs, data, etc. The RAM  503  is a volatile storage device that is used as a work area of the CPU  501  and into which programs, data, etc., are loaded. 
     The auxiliary storage device  504  is a storage device, such as a hard disk drive (HDD), a solid state drive (SSD), or a flash memory, and is a storage for storing image data, programs, font data, forms, etc. 
     The network I/F  505  is an interface for communicating with an external device that is connected via the network N that is configured by a wired or wireless data transmission line. The network I/F  505  is, for example, an interface according to the TCP (Transmission Control Protocol)/IP (Internet Protocol). 
     The image forming unit  506  is a printing device that performs image formation (printing) by ejecting ink onto a recording medium by the inkjet system. 
     The read unit  507  is a scanner that performs a read operation on a recording medium on which the image forming unit  506  has performed image formation is performed by. 
     The CPU  501 , the ROM  502 , the RAM  503 , the auxiliary storage device  504 , the network I/F  505 , the image forming unit  506 , and the read unit  507  are connected via buses, such as an address bus and a data bus, such that they are able to communicate with one another. 
     The hardware configuration of the image forming apparatus  1  illustrated in  FIG.  2    illustrates an example, and the image forming apparatus  1  need not include all the components illustrated in  FIG.  2    and the image forming apparatus  1  may include other components. 
     Hardware Configuration of DFE 
       FIG.  3    is a diagram illustrating an example of a hardware configuration of the DFE according to the embodiment. With reference to  FIG.  3   , the hardware configuration of the DFE  2  according to the embodiment will be described. 
     As illustrated in  FIG.  3   , the DFE  2  includes a CPU  551 , a ROM  552 , a RAM  553 , an auxiliary storage device  554 , and a network I/F  555 . 
     The CPU  551  is an arithmetic logic unit that controls general operations of the DFE  2 . The ROM  552  is a non-volatile storage device that stores a program for the DFE  2 . The RAM  553  is a volatile storage device that is used as a work area of the CPU  551 . 
     The auxiliary storage device  554  is a storage device that stores various types of data and programs, such as a HDD or a SSD. 
     The network I/F  555  is an interface for performing data communication with the image forming apparatus  1 , the client PC  3 , and the management server  4  using the network N. The network I/F  555  is, for example, a network interface card (NIC) that corresponds to Ethernet (trademark) and that is capable of communication according to TCP/IP, or the like. 
     The CPU  551 , the ROM  552 , the RAM  553 , the auxiliary storage device  554 , and the network I/F  555  are connected such that they are able to communicate with one another via buses, such as an address bus and a data bus. 
     The hardware configuration of the DFE  2  illustrated in  FIG.  3    represents an example, and the DFE  2  need not include all the components illustrated in  FIG.  3    and the DFE  2  may include other components. 
     Hardware Configuration of Client PC and Management Server 
       FIG.  4    is a diagram illustrating an example of a hardware configuration of the client PC according to the embodiment. With reference to  FIG.  4   , the hardware configurations of the client PC  3  and the management server  4  according to the embodiment will be described. Note that the configurations will be described below as the configuration of the client PC  3 . 
     As illustrated in  FIG.  4   , the client PC  3  includes a CPU  601 , a ROM  602 , a RAM  603 , an auxiliary storage device  605 , a media drive  607 , a display  608 , a network I/F  609 , a keyboard  611 , a mouse  612 , and a digital versatile disc (DVD) drive  614 . 
     The CPU  601  is an arithmetic logic unit that controls general operations of the client PC  3 . The ROM  602  is a non-volatile storage device that stores a program for the client PC  3 . The RAM  603  is a volatile storage device that is used as a work area of the CPU  601 . 
     The auxiliary storage device  605  is a storage device that stores various types of data and programs, such as a HDD or a SSD. The media drive  607  is a device that controls reading data from and writing data in a recording medium  606 , such as a flash memory, according to the control of the CPU  601 . 
     The display  608  is a display device that displays various types of information, such as a cursor, a menu, a window, letters and images, and that consists of liquid crystals or electroluminescence (EL), etc. 
     The network I/F  609  is an interface for performing data communication with external devices, such as the DFE  2  and the management server  4 , via the network N. The network I/F  609  is, for example, a NIC that corresponds to Ethernet and that is capable of communication according to TCP/IP. 
     The keyboard  611  is an input device for selecting a character, a number and various instructions, moving a cursor, etc. The mouse  612  is an input device for selecting and executing various instructions, selecting a subject to be processed, moving a cursor, etc. 
     The DVD drive  614  is a device, such as a DVD ROM or a DVD-R (Digital Versatile Disk Recordable) serving as an example of a detachable recording medium, that controls reading of data from and writing of data in a DVD  613 . 
     The CPU  601 , the ROM  602 , the RAM  603 , the auxiliary storage device  605 , the media drive  607 , the display  608 , the network I/F  609 , the keyboard  611 , the mouse  612 , and the DVD drive  614  that are described above are connected such that they communicate with one another via a bus line  610 , such as an address bus and a data bus. 
     The hardware configuration of the client PC  3  illustrated in  FIG.  4    represents an example and the client PC  3 , and the client PC  3  need not include all the components illustrated in  FIG.  4    and the client PC  3  may include other components. 
     The hardware configuration of the management server  4  also accords with the hardware configuration illustrated in  FIG.  4   . 
     Schematic Configuration of Image Forming Apparatus 
       FIG.  5    is a diagram illustrating an example of the schematic configuration the image forming apparatus according to the embodiment. With reference to  FIG.  5   , the mechanical schematic configuration of the image forming apparatus  1  according to the embodiment will be described. 
     As described above, the image forming apparatus  1  is an inkjet printer that performs image forming (printing) on a recording medium by the inkjet system. As illustrated in  FIG.  5   , the image forming apparatus  1  includes a sheet feeder  100 , an image forming unit  110 , a drier  120 , and a sheet ejector  130 . In the image forming apparatus  1 , the image forming unit  110  forms an image using ink that is liquid for image formation on a recording medium P that serves as a sheet member and that is fed from the sheet feeder  100 , the drier  120  dries the ink that is attached onto the recording medium P, and the sheet ejector  130  ejects the recording medium P. 
     The sheet feeder  100  is a unit that feeds the recording medium P serving as a sheet member to the image forming unit  110 . The sheet feeder  100  includes a sheet feeding tray  101 , a feeding device  102 , and a registration roller pair  103 . 
     The sheet feeding tray  101  is a tray on which a plurality of recording media P can be placed. 
     The feeding device  102  is a device that separates the recording media P one by one from the sheet feeding tray  101  and sends out the recording medium P to a conveying path. Various devices, such as a device using a roller or a device utilizing air suction, are usable as the feeding device  102 . 
     The registration roller pair  103  includes a pair or rollers that send out the recording medium P that is sent out by the feeding device  102  at given timing to the image forming unit  110 . 
     The sheet feeder  100  is not limited to the configuration illustrated in  FIG.  5    as long as the sheet feeder  100  has a mechanism capable of sending out the recording medium P to the image forming unit  110 . 
     The image forming unit  110  is a unit that forms an image using ink that is liquid for image formation on the recording medium P that is fed from the sheet feeder  100 . The image forming unit  110  can be regarded as the liquid ejection apparatus. The image forming unit  110  includes a receiving body  111 , a sheet carrier drum  112 , a suction device  113 , an inkjet head  114 , a passing body  115 , and a control board  116 . 
     The receiving body  111  is a roller member that receives the recording medium P that is fed from the sheet feeder  100 . The receiving body  111  grips the received recording medium P with a sheet gripper that is provided on the surface of the receiving body  11  and conveys the recording medium P to the sheet carrier drum  112  along the surface. 
     The sheet carrier drum  112  is a drum member that carries the recording medium P, which is conveyed by the receiving drum  111 , on the outer circumferential surface of the sheet carrier drum  112  and conveys the recording medium P along the circumferential surface. A sheet gripper is arranged also on the surface of the sheet carrier drum  112  and an end of the recording medium P is gripped by the sheet gripper. A plurality of suction holes are formed dispersedly on the outer circumferential surface of the sheet carrier drum  112 . 
     The suction device  113  is a device that generates a suction airflow toward the inside of the sheet carrier drum  112  from each of the suction holes that are formed on the outer circumferential surface of the sheet carrier drum  112 , thereby causing the recording medium P to be attracted onto the outer circumferential surface of the sheet carrier drum  112 . 
     The inkjet head  114  is a liquid ejection head that ejects ink to the recording medium P that is carried by the sheet carrier drum  112 , thereby forming an image. The inkjet head  114  includes an inkjet head  114 C that ejects a cyan (C) ink, an inkjet head  114 M that ejects a magenta (M) ink, an inkjet head  114 Y that ejects a yellow (Y) ink, and an inkjet head  114 K that ejects a black (K) ink and forms an image by ejecting the inks of four colors. In other words, the inkjet heads  114 C,  114 M,  114 C and  114 K eject the respective colors when the recording medium P that is carried on the sheet carrier drum  112  passes the opposed are, thereby forming an image corresponding to the image data. The word “inkjet head  114 ” is used to refer to any one of the inkjet heads  114 C,  114 M,  114 C and  114 K or collectively refer to the inkjet heads  114 C,  114 M,  114 C and  114 K. The configurations of the inkjet heads  114 C,  114 M,  114 C and  114 K are not limited as long as the inkjet heads  114 C,  114 M,  114 C and  114 K are able to eject ink and various configurations can be employed. An inkjet head that ejects special ink of, white, gold, silver or the like, may be arranged as required or a liquid ejection head that ejects liquid not forming an image, such as a coating solution, may be arranged. An electric configuration of the inkjet head  114  will be described below using  FIG.  6   . 
     The passing body  115  is a roller member that passes the recording medium P that is conveyed by the sheet carrier drum  112  to the drier  120 . 
     The control board  116  is a control board that controls an ink ejection operation of the inkjet head  114 . The control board  116  controls the ejection operation of the inkjet head  114  according to a drive signal (drive waveform) corresponding to the image data. 
     The drier  120  is a unit that dries the ink that is adhered onto the recording medium P with the image formed thereon by the image forming unit  110 . The drier  120  includes a drying mechanism  121  and a conveyance mechanism  122 . 
     The drying mechanism  121  is a mechanism that performs drying processing on the ink on the recording medium P that is conveyed by the conveyance mechanism  122  to cause the moisture in the ink to evaporate, thereby causing the ink to adhere onto the recording medium P and inhibiting the recording medium P from curling. 
     The conveyance mechanism  122  is a mechanism that receives the recording medium P, which is conveyed from the image forming unit  110 , and conveys the recording medium P through the drier  120 . 
     The sheet ejector  130  is a unit for stacking the recording media P that are conveyed from the drier  120 . The sheet ejector  130  includes a sheet ejection tray  131 . 
     The sheet ejection tray  131  is a tray on which the recording media P that are conveyed from the drier  120  are stacked sequentially and stored. 
     The sheet ejector  130  is not limited to the configuration illustrated in  FIG.  5    as long as the sheet ejector is able to eject the recording medium P. 
     The image forming apparatus  1  illustrated in  FIG.  5    is configured such that the image forming apparatus  1  includes the sheet feeder  100 , the image forming unit  110 , the drier  120 , and the sheet ejector  130 , and another unit may be added as appropriate. For example, a pre-processor that performs pre-processing of image formation may be added between the sheet feeder  100  and the image forming unit  110  or a post-processor that performs post-processing of image formation may be added between the drier  120  and the sheet ejector  130 . A processor that performs a processing solution application process of applying a processing solution that reacts with ink and inhibits bleeding to the recording medium P may be taken as the pre-processor and the content of the pre-processor is not particularly limited. For example, a sheet inversion conveyance processor for inverting the recording medium P with the image formed thereon by the image forming unit  110 , sending the recording medium P to the image forming unit  110  again to form images on both the surfaces of the recording medium P, a processor that binds a plurality of recording media P with images formed thereon, a correction mechanism processor that corrects sheet deformation, or a cooling processor that cools the recording medium P is taken as the post processor, and the content of the post processor is not particularly limited. 
     Configurations of Control Board and Inkjet Head of Image Forming Apparatus 
       FIG.  6    is a diagram illustrating an example of configurations of the control board and the inkjet head of the image forming apparatus according to the embodiment. With reference to  FIG.  6   , the configurations of the control board  116  and the inkjet head  114  of the image forming apparatus  1  according to the embodiment will be described. 
     As described above, the control board  116  is a control board that controls an operation of ejecting ink performed by the inkjet head  114 . As illustrated in  FIG.  6   , the control board  116  includes a transmission-side control device  201  and an analog circuit  202 . 
     The transmission-side control device  201  is a device that consists of a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), or the like, and that transmits latch signals for image data (simply referred to as latch signals below), image data for selecting a drop type, and timing data (mask data) for selecting on or off of an analog switch to the inkjet head  114 . As illustrated in  FIG.  6   , the transmission-side control device  201  includes a data divider  211  (divider), a check data adder  212  (adder), and a transmitter  213  (first transmitter) as functional processors. 
     The data divider  211  is a processor that divides image data into a plurality of data chronologically. 
     The check data adder  212  is a processor that adds check data, such as a checksum of a parity for error detection to each of the image data that are divided by the data divider  211  (division data). 
     The transmitter  213  is a processor that transmits each of the image data that are divided by the data divider  211  and to which check data is added by the check data adder  212  to the inkjet head  114 . The transmitter  213  further transmits the aforementioned latch signal and timing data (mask data) to the inkjet head  114 . The latch signal is a signal serves as a reference of the timing of data transmission from the transmission-side control device  201  to a reception-side control device  301 . 
     The analog circuit  202  is a circuit that generates a drive waveform that is referred to as VCOM and transmits the drive waveform to a piezoelectric drive device  321  of the inkjet head  114  to be described below. 
     As described above, the inkjet head  114  is a liquid ejection head that ejects ink to the recording medium P that is carried on the sheet carrier drum  112  to form an image. As illustrated in  FIG.  6   , the inkjet head  114  includes a head board  300 , a piezoelectric support substrate  320 , and piezoelectric elements  330   a ,  330   b, . . . .    
     The head board  300  includes a reception-side control device  301 . 
     The reception-side control device  301  is a device that consists of a FPGA, an ASIC, or the like, and that receives the latch signal, the image data and the timing data (mask data), which are transmitted from the transmission-side control device  201 , and that performs various types of processing. As illustrated in  FIG.  6   , the reception-side control device  301  includes a receiver  311 , a data checker  312  (error detector), a data restoration unit  313 , and a transmitter  314  (second transmitter) as functional processors. 
     The receiver  311  is a processor that receives the latch signal, the image data, and the timing data (mask data) that are transmitted from the transmission-side control device  201 . 
     The data checker  312  is a processor that performs error detection on image data received from the receiver  311 , using check data that is added to the image data. The control board  116  and the inkjet head  114  are often connected via a harness for transmitting and receiving data and there is a risk that a data error in the image data would occur due to the effect of noise, or the like. Thus, in the image forming apparatus  1  according to the present embodiment, as described above, the check data adder  212  adds check data to image data and the data checker  312  performs data detection on the image data using the check data. 
     The data restoration unit  313  is a processor that, when the check data adder  212  has added a horizontal parity and a vertical parity as check data to image data, performs a so-called two-dimensional parity check using the horizontal parity and the vertical parity and restores image data in which the data checker  312  has detected an error. In the image forming apparatus  1  according to the present embodiment, the data restoration unit  313  is not necessarily required, and the data restoration unit  313  may be not included. 
     The transmitter  314  is a processor that transmits the image data on which the data checker  312  has performed an error detection process and the timing data (mask data) to the piezoelectric drive device  321  to be described below. Specifically, the transmitter  314  transmits image data in which the data checker  312  detects no error or image data that is restored by the data restoration unit  313  in the case where the data checker  312  detects an error in image data to the piezoelectric drive device  321 . When the data restoration unit  313  fails in restoration, the transmitter  314  transmits image data of the same area preceding the image data by one period (for example, preceding by one scan). In the case where the data restoration unit  313  is not included, when the data checker  312  detects an error in image data, the transmitter  314  may transmit image data of the same area preceding the image data by one period, instead of the image data. 
     Details of a restoration process by the data restoration unit  313  and a process of transmitting image data preceding by one period by the transmitter  314  will be described below using  FIG.  10   . 
     The piezoelectric support substrate  320  includes the piezoelectric drive device  321 . 
     The piezoelectric drive device  321  is a device that generates analog signals that are applied to the piezoelectric elements  330   a ,  330   b , . . . , using an internal switch circuit (not illustrated in the drawing) based on the image data and the timing data (mask data), which are received from the reception-side control device  301 , and the VCOM, which is received from the analog circuit  202 . The piezoelectric drive device  321  loads data from the reception-side control device  301  at the timing when the reception-side control device  301  receives the latch signal. 
     The piezoelectric elements  330   a ,  330   b , . . . are piezoelectric elements that are displaced according to the voltage of the analog signal that is applied from the piezoelectric drive device  321  and that eject ink from nozzle holes. 
     Part or all the data divider  211 , the check data adder  212 , the transmitter  213 , the receiver  311 , the data checker  312 , the data restoration unit  313 , and the transmitter  314  may be implemented not by a hardware circuit, such as an integrated circuit, but by the CPU  501  by executing a program. 
     Image Data Transmission and Reception by Conventional Image Forming Apparatus 
       FIG.  7    is a diagram illustrating an example of a timing chart of data transmission and reception in a conventional image forming apparatus.  FIG.  8    is a diagram illustrating an example of a timing chart in the case where the interval of latch signals is short in the conventional image forming apparatus. With reference to  FIGS.  7  and  8   , image data transmission and reception by the conventional image forming apparatus will be described. 
     As described above, transmission of data, such as image data and timing data (mask data), from the transmission-side control device to the reception-side control device is performed based on a latch signal. Check data for error detection, such as a checksum or a parity (for example, the check data CK illustrated in  FIG.  7   ) is added to image data to be transmitted (for example, image data D illustrated in  FIG.  7   ). The reception-side control device performs error detection on the image data using the check data and, when no error is detected in the image data, transfers the image data, etc., to the piezoelectric drive device. The piezoelectric drive device receives the image data that is transferred from the reception-side control device and loads the image data into an internal circuit according to the latch signal. 
     The above-described latch signal is a signal corresponding to a period of ejection of ink in the inkjet head and therefore, in the case where the printing speed increases, or the case where accurate printing is performed, or the like, the ejection period shortens and the period of latch signal shortens, too. When the period of latch signal shortens as described above, as illustrated in  FIG.  8   , there is a risk that the timing of the next latch signal would come during the transfer of image data from the reception-side control device to the piezoelectric drive device and the piezoelectric drive device loads the image data into the internal circuit in the state of not having received all the image data and this would result in abnormal data and an abnormal image would be printed on a recording medium. 
     In order to solve the above-described problem, the image forming apparatus  1  according to the present embodiment performs the following operations illustrated in  FIG.  9    and  FIG.  10   . 
     Image Data Transmission and Reception by Image Forming Apparatus according to Present Embodiment 
       FIG.  9    is a diagram illustrating an example of a timing chart of data transmission and reception in the image forming apparatus according to the embodiment.  FIG.  10    is a diagram illustrating an example of a timing chart of data transmission and reception in the case where data is transmitted as a substitute in the image forming apparatus according to the embodiment. With reference to  FIG.  9    and  FIG.  10   , image data transmission and reception by the image forming apparatus  1  according to the embodiment will be described. 
     In the embodiment, when image data is transmitted during one period of latch signal to the reception-side control device  301  from the transmission-side control device  201 , check data is not added to the image data and the following processing is performed. In other words, when image data is transmitted from the transmission-side control device  201  to the reception-side control device  301 , the data divider  211  of the transmission-side control device  201  chronologically divides the image data into a plurality of image data D 1 , D 2 , . . . as illustrated in  FIG.  9   . The check data adder  212  of the transmission-side control device  201  then adds check data CK 1 , CK 2 , . . . , such as checksums or parities for error detection, to the image data D 1 , D 2  . . . that are divided by the data divider  211 . The transmitter  213  of the transmission-side control device  201  transmits the image data D 1 , D 2 , . . . that are divided by the data divider  211  and to which the check data adder  212  adds the check data CK 1 , CK 2 , . . . to the reception-side control device  301  of the inkjet head  114 . 
     The receiver  311  of the reception-side control device  301  receives the image data D 1 , D 2 , . . . to which the check data CK 1 , CK 2 , . . . are added. Every time the receiver  311  receives image data, the data checker  312  of the reception-side control device  301  performs error detection on each set of image data using check data (check data CK 1 , CK 2 , . . . ) that is added to the image data (image data D 1 , D 2  . . . ). Accordingly, in the reception-side control device  301 , as illustrated in  FIG.  9   , without reception of the whole image data, the transmitter  314  is able to transmit a set of image data on which error detection process has been performed to the piezoelectric drive device  321  at the time when error detection completes on a divided image data basis. In other words, as illustrated in  FIG.  9   , reception of image data from the transmission-side control device  201  to the reception-side control device  301  and transmission of image data from the reception-side control device  301  to the piezoelectric drive device  321  are executable in parallel. Thus, as illustrated in  FIG.  8    described above, it is possible to avoid the situation with the conventional technique where image data cannot be transmitted completely until the next latch signal and the above-described parallel processing makes it possible to perform error detection on image data and increase the printing speed.  FIG.  9    illustrates the example in which transmission of the image data D 2  from the transmission-side control device  201  to the reception-side control device  301  and transmission of the image data D 1  from the reception-side control device  301  to the piezoelectric drive device  321  are performed in parallel; however, transmission is not limited to this. For example, transmission of the image data (the image data D 3  not illustrated in the drawing) following the image data D 2  from the transmission-side control device  201  to the reception-side control device  301  and transmission of the image data D 1  from the reception-side control device  301  to the piezoelectric drive device  321  may be performed in parallel. 
     In the case where the reception-side control device  301  includes the data restoration unit  313 , when the check data adder  212  adds a horizontal parity and a vertical parity as check data to image data, the data restoration unit  313  performs a so-called two-dimensional parity examination using the horizontal parity and the vertical parity and restores the image data in which the data checker  312  has detected an error. The transmitter  314  of the reception-side control device  301  transmits, to the piezoelectric drive device  321 , image data in which no error has been detected in the error detection process performed by the data checker  312  or image data that is restored by the data restoration unit  313  when the data checker  312  detects an error in the image data. When the data restoration unit  313  fails in restoration, the transmitter  314  transmits image data of the same area preceding the image data by one period (for example, preceding by one scan) (for example, as illustrated in  FIG.  10   , the image data D 2   a  preceding the divided image data D 2  by one period). Note that, in the case where the data restoration unit  313  is not included, when the data checker  312  detects an error in image data, the transmitter  314  may transmit image data of the same area preceding the image data by one period. Accordingly, even when an error occurs in image data (even when it is not possible to restore the image data with the error), it is possible to perform a printing process that makes it difficult to determine an abnormal image visually. 
     When at least any of the processors of the image forming apparatus  1  is implemented by executing a program in the above-described embodiment, the program is provided by incorporating in a ROM, or the like, previously. In the above-described embodiment, a program to be executed by the image forming apparatus  1  may be configured such that the program is recorded in a file in an installable or executable form in a computer-readable recording medium, such as a CD-ROM (Compact Disc Read Only Memory), a flexible disc (FD), a CD-R (Compact Disc-Readable) or a DVD (Digital Versatile Disc). In the above-descried embodiment, a program to be executed by the image forming apparatus  1  may be configured such that the program is stored in a computer that is connected to a network, such as the Internet, is downloaded via the network, and thus is provided. In the above-described embodiment, a program to be executed by the image forming apparatus  1  has a module configuration including at least any one of the processors described above and, as for actual hardware, the CPU  501  reads the program from the above-described storage device (the ROM  502  or the auxiliary storage device  504 ) and executes the program, so that each of the above-described processors is loaded in the main storage device (the RAM  503 ) and is generated. 
     According to an embodiment, it is possible to increase a printing speed while performing error detection on image data to an inkjet head. 
     The above-described embodiments are illustrative and do not limit the present invention. Thus, numerous additional modifications and variations are possible in light of the above teachings. For example, at least one element of different illustrative and exemplary embodiments herein may be combined with each other or substituted for each other within the scope of this disclosure and appended claims. Further, features of components of the embodiments, such as the number, the position, and the shape are not limited the embodiments and thus may be preferably set. It is therefore to be understood that within the scope of the appended claims, the disclosure of the present invention may be practiced otherwise than as specifically described herein. 
     The method steps, processes, or operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance or clearly identified through the context. It is also to be understood that additional or alternative steps may be employed. 
     Further, any of the above-described apparatus, devices or units can be implemented as a hardware apparatus, such as a special-purpose circuit or device, or as a hardware/software combination, such as a processor executing a software program. 
     Further, as described above, any one of the above-described and other methods of the present invention may be embodied in the form of a computer program stored in any kind of storage medium. Examples of storage mediums include, but are not limited to, flexible disk, hard disk, optical discs, magneto-optical discs, magnetic tapes, nonvolatile memory, semiconductor memory, read-only-memory (ROM), etc. 
     Alternatively, any one of the above-described and other methods of the present invention may be implemented by an application specific integrated circuit (ASIC), a digital signal processor (DSP) or a field programmable gate array (FPGA), prepared by interconnecting an appropriate network of conventional component circuits or by a combination thereof with one or more conventional general purpose microprocessors or signal processors programmed accordingly. 
     Each of the functions of the described embodiments may be implemented by one or more processing circuits or circuitry. Processing circuitry includes a programmed processor, as a processor includes circuitry. A processing circuit also includes devices such as an application specific integrated circuit (ASIC), digital signal processor (DSP), field programmable gate array (FPGA) and conventional circuit components arranged to perform the recited functions.