Image forming apparatus, image data transfer method, and program

Abstract

To synchronize a plurality of pieces of division image data to be transferred by using a main scan synchronous signal and sub-scan synchronous signals.SOLUTION: A transfer apparatus 200 transfers a plurality of pieces of division image data from a transmitting device to a receiving device. The receiving device generates sub-scan synchronous signals for defining effective areas in a sub-scanning direction of the plurality of pieces of division image data and sends the generated signals to the transmitting device. A first processing unit executes first processing on the basis of the first sub-scan synchronous signal input not through the transmitting device. A second processing unit executes second processing on the basis of the second sub-scan synchronous signal input through the transmitting device. A delay unit delays the first sub-scan synchronous signal according to a time shift between the first and second sub-scan synchronous signals. The transmitting device generates a main scan synchronous signal to be a reference for synchronizing the plurality of pieces of division image data in a main scanning direction orthogonal to the sub-scanning direction, and adjusts timing of the sub-scan synchronous signals according to the timing shift between the main scan synchronous signal and the second sub-scan synchronous signal.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus, an image data transfer method, and a program. [Background technology]

[0002] In an image forming apparatus capable of transferring multiple pieces of divided image data, which are obtained by dividing one image data, from a transmitting device to a receiving device, a technique is known in which multiple pieces of divided image data are transferred in synchronization with a synchronization signal, without adjustment using an analog signal. The synchronization signal includes a main-scanning synchronization signal, which is a synchronization signal in the main scanning direction, and a sub-scanning synchronization signal, which is a synchronization signal in the sub-scanning direction perpendicular to the main scanning direction.

[0003] Also, a technique has been disclosed in which a plurality of pieces of divided image data to be transferred are synchronized by using a common sub-scanning synchronization signal generated by a transmitting device (see, for example, Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] However, when synchronization is performed using a sub-scanning synchronization signal generated by the receiving device and a sub-scanning synchronization signal transmitted from the transmitting device, conventional technology cannot be applied, and there is room for improvement in accurately synchronizing multiple divided image data being transferred.

[0005] An object of the present invention is to accurately synchronize a plurality of pieces of divided image data to be transferred using a sub-scanning synchronization signal generated by a receiving device and a sub-scanning synchronization signal transmitted from a transmitting device. [Means for solving the problem]

[0006] An image forming apparatus according to one aspect of the present invention is an image forming apparatus capable of transferring a plurality of divided image data obtained by dividing image data from a transmitting device to a receiving device, the receiving device having a sub-scanning synchronization generation unit that generates a sub-scanning synchronization signal that defines an effective area in a sub-scanning direction of the plurality of divided image data, a first processing unit that executes a first process based on a first sub-scanning synchronization signal among the sub-scanning synchronization signals that is input without passing through the transmitting device, a second processing unit that executes a second process based on a second sub-scanning synchronization signal among the sub-scanning synchronization signals that is input via the transmitting device, and a delay unit that delays the first sub-scanning synchronization signal in accordance with a time lag between the first sub-scanning synchronization signal and the second sub-scanning synchronization signal, the transmitting device having a main-scanning synchronization generation unit that generates a main-scanning synchronization signal that is a reference for synchronizing the plurality of divided image data in a main scanning direction perpendicular to the sub-scanning direction, the main-scanning synchronization signal, Among the sub-scanning synchronization signals, a sub-scanning synchronization signal input to the transmitting device Depending on the timing difference between Input to the transmitting device an adjustment unit that adjusts the timing of the sub-scanning synchronization signal; The adjustment unit outputs the second sub-scanning synchronization signal. . Effect of the Invention

[0007] According to the present invention, a plurality of pieces of divided image data to be transferred can be accurately synchronized using a sub-scanning synchronization signal generated by the receiving device and a sub-scanning synchronization signal transmitted from the transmitting device. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram illustrating an example of a hardware configuration of an image forming apparatus according to an embodiment. [Diagram 2] FIG. 2 is a block diagram of a configuration example of a transfer device according to an embodiment. [Diagram 3] 2 is a block diagram illustrating an example of a functional configuration of a transfer device according to the first embodiment. FIG. [Figure 4] 4 is a timing chart of an example of the operation of the delay unit according to the first embodiment. [Diagram 5] 13 is a timing chart showing a case where there is no timing deviation. [Figure 6] 13 is a timing chart showing a case where there is a timing deviation. [Figure 7] 5 is a timing chart showing the operation of the adjustment unit. [Figure 8] FIG. 4 is a flowchart of a process example performed by the image forming apparatus according to the first embodiment. [Figure 9] FIG. 11 is a block diagram of an example of a functional configuration of a transfer device according to a comparative example. [Figure 10] FIG. 11 is a block diagram of an example of a functional configuration of a CPU according to a second embodiment. [Figure 11] FIG. 11 is a flowchart of a process example performed by an image forming apparatus according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In each drawing, the same components are given the same reference numerals, and duplicated explanations will be omitted as appropriate.

[0010] The image forming apparatus according to the embodiment is capable of transferring a plurality of divided image data obtained by dividing image data from a transmitting device to a receiving device, and the image forming apparatus accurately synchronizes the transferred plurality of divided image data using the sub-scanning synchronization signal generated by the receiving device and the sub-scanning synchronization signal transmitted from the transmitting device by adjusting the timing of the sub-scanning synchronization signal in accordance with a timing shift of the sub-scanning synchronization signal relative to the main-scanning synchronization signal generated by the transmitting device.

[0011] <Terminology in the embodiment> (Split image data) Split image data refers to each image data that is the result of splitting one image data into multiple pieces. Examples of split image data include image data in which an image area is split into multiple areas, or color image data divided by color, etc.

[0012] (Main scanning direction) The main scanning direction refers to one of the two directions in which a plurality of pixel data constituting two-dimensional image data are arranged.

[0013] (Sub-scanning direction) The sub-scanning direction is the other of the two directions in which the multiple pixel data that make up two-dimensional image data are arranged, and is the direction perpendicular to the main scanning direction. Two-dimensional image data is composed by arranging lines of pixel data arranged in the main scanning direction in the sub-scanning direction.

[0014] (Main scan sync signal) The main scanning synchronization signal is a signal that serves as a reference for synchronizing a plurality of pieces of divided image data to be transferred in the main scanning direction.

[0015] (Sub-scan sync signal) The sub-scanning synchronization signal is a signal that defines the effective area of ​​each of the multiple divided image data in the sub-scanning direction. The sub-scanning synchronization signal includes a first sub-scanning synchronization signal that is input from the sub-scanning synchronization generator through a first path without passing through a transmitting device, and a second sub-scanning synchronization signal that is input from the sub-scanning synchronization generator through a second path via a transmitting device.

[0016] (Sub-scanning effective area signal) The sub-scanning effective area signal is a signal that indicates the period from the start to the end of the effective area in the sub-scanning direction of a plurality of divided image data.

[0017] (effective area) The valid area refers to the valid image area of ​​the image data, whereas the invalid area refers to an edge area of ​​the image data.

[0018] (First process, second process) The first process refers to a process executed by a first processing unit among processes executed on a plurality of divided image data. The second process refers to a process executed by a second processing unit among processes executed on a plurality of divided image data. Both the first and second processes are image processing, processing for displaying an image on a display or the like, processing for outputting image data to an external device, etc. In the embodiment, a case where both the first process and the second process are image processing will be described as an example.

[0019] (assertion edge) An assert edge refers to the timing of a rising edge of a signal that makes a signal or logic valid.

[0020] <Hardware Configuration of Image Forming Apparatus 100> First, a hardware configuration of an image forming apparatus 100 according to an embodiment will be described. The image forming apparatus 100 is an electronic device equipped with a printing function, such as an MFP (Multifunction Peripheral / Printer / Product) that has a scanning function, a copying function, a printing function, a facsimile function, and the like mounted in one housing, or a printer.

[0021] Fig. 1 is a block diagram showing an example of a hardware configuration of an image forming apparatus 100. As shown in Fig. 1, the image forming apparatus 100 includes a controller 910, a short-range communication circuit 920, an engine control unit 930, an operation panel 940, and a network I / F 945.

[0022] Of these, the controller 910 includes a CPU (Central Processing Unit) 901, which is the main part of the computer, a system memory (MEM-P) 902, a north bridge (NB) 903, and a south bridge (SB) 904. It also includes an ASIC (Application Specific Integrated Circuit) 906, a local memory (MEM-C) 907, which is a storage unit, an HDD controller 908, and a HD 909, which is a storage unit. The NB 903 and the ASIC 906 are connected by an AGP (Accelerated Graphics Port) bus 921.

[0023] The CPU 901 is a control unit that performs overall control of the image forming apparatus 100. The NB 903 is a bridge for connecting the CPU 901 with the MEM-P 902, the SB 904, and the AGP bus 921. The NB 903 includes a memory controller that controls reading and writing to the MEM-P 902, a PCI (Peripheral Component Interconnect) master, and an AGP target.

[0024] The MEM-P 902 includes a ROM (Read Only Memory) 902a, which is a memory for storing programs and data that realize the functions of the controller 910, and a RAM (Random Access Memory) 902b, which is used as a drawing memory for memory printing and the like, and for expanding the programs and data. The programs stored in the RAM 902b may be provided by being recorded in a computer-readable recording medium such as a CD-ROM, CD-R, or DVD in the form of an installable or executable file.

[0025] The SB 904 is a bridge for connecting the NB 903 with PCI devices and peripheral devices. The ASIC 906 is an IC (Integrated Circuit) for image processing purposes that includes hardware elements for image processing, and serves as a bridge for connecting the AGP bus 921, the PCI bus 922, the HDD (Hard Disk Drive) 908, and the MEM-C 907.

[0026] This ASIC 906 includes a PCI target and an AGP master, an arbiter (ARB) that is the core of the ASIC 906, and a memory controller that controls the MEM-C 907. It also includes a plurality of DMACs (Direct Memory Access Controllers) that perform image data rotation and the like using hardware logic and the like, and a PCI unit that transfers data between a scanner unit 931 and a printer unit 932 via a PCI bus 922.

[0027] The ASIC 906 may be connected to a Universal Serial Bus (USB) interface or an Institute of Electrical and Electronics Engineers 1394 (IEEE1394) interface.

[0028] The MEM-C 907 is a local memory used as an image buffer for copying and a code buffer. The HD 909 is a storage for storing image data, font data used during printing, forms, and the like.

[0029] The HD 909 controls reading and writing of data from and to the HD 909 under the control of the CPU 901. The AGP bus 921 is a bus interface for a graphics accelerator card proposed to speed up graphic processing. By directly accessing the MEM-P 902 with high throughput, the graphics accelerator card can be made faster.

[0030] The short-distance communication circuit 920 also includes a communication unit 920a. The short-distance communication circuit 920 is a communication circuit such as Near Field Communication (NFC) or Bluetooth (registered trademark).

[0031] Furthermore, the engine control unit 930 includes a scanner unit 931 and a printer unit 932. The operation panel 940 includes a panel display unit 940a such as a touch panel that displays current setting values, a selection screen, and the like and receives input from an operator, and an operation panel 940b including a numeric keypad that receives setting values ​​for image formation conditions such as density setting conditions, and a start key that receives a copy start instruction.

[0032] The controller 910 controls the entire image forming apparatus 100, for example, controlling drawing, communication, and input from an operation panel 940. The scanner unit 931 or the printer unit 932 includes an image processing unit that performs error diffusion, gamma conversion, and the like.

[0033] In addition, the image forming apparatus 100 can select the document box function, copy function, printer function, and facsimile function by sequentially switching between them using the application switching key on the operation panel 940.

[0034] When the document box function is selected, the document box mode is selected; when the copy function is selected, the copy mode is selected; when the printer function is selected, the printer mode is selected; and when the facsimile mode is selected, the facsimile mode is selected.

[0035] The network I / F 950 is an interface for performing data communication using a communication network. The short-range communication circuit 920 and the network I / F 950 are electrically connected to the ASIC 906 via a PCI bus 922.

[0036] Furthermore, image forming apparatus 100 includes a controller transfer unit 950 and a CPU 960. Controller transfer unit 950 is an electric circuit that transfers image data (original data) of an original read by scanner unit 931 to controller 910. The transfer of image data from scanner unit 931 to controller transfer unit 950 is performed by transfer device 200, which will be described below. CPU 960 is a processor that controls the transfer of image data from scanner unit 931 to controller transfer unit 950 by transfer device 200, etc.

[0037] <Configuration of transfer device 200> Fig. 2 is a block diagram showing an example of the configuration of a transfer device 200 included in the image forming device 100. Fig. 2 shows the transfer device 200 enclosed by a dashed line, together with the peripheral configuration of the transfer device 200 in the image forming device 100.

[0038] In FIG. 2, among the signals transmitted from the transmitting device 300 to the receiving device 400, the signals indicated by dashed arrows represent multiple divided image data, the signals indicated by dashed arrows represent main scanning synchronization signals, and the signals indicated by dashed double-dashed lines represent sub-scanning synchronization signals.

[0039] 2, the scanner unit 931 includes a transmitting device 300 and a reading unit 970. The controller transfer unit 950 includes a receiving device 400 and a memory 980. The transmitting device 300 included in the scanner unit 931 and the receiving device 400 included in the controller transfer unit 950 configure the transfer apparatus 200.

[0040] The reading unit 970 reads an original placed on a platen using an optical system such as a lens, and outputs the read analog data to the transmitting device 300 .

[0041] The transmitting device 300 is an electronic circuit that converts analog data input from the reading unit 970 into digital image data and transfers it to the controller transfer unit 950 in LVDS (Low Voltage Differential Signaling) format. Here, LVDS is a digital wired transmission method suitable for short-distance transmission, and refers to a small-amplitude, low-power consumption, high-speed differential interface.

[0042] The transmitting device 300 divides image data, distributes the divided image data, and transmits the divided image data to each of the multiple channels. The transmitting device 300 also transfers main scanning synchronization signals and sub scanning synchronization signals for synchronizing the divided image data between the multiple channels, together with the divided image data, from the multiple channels to the receiving device 400 by LVDS differential signals.

[0043] The receiving device 400 is an electronic circuit that receives a plurality of pieces of divided image data for each of a plurality of channels, performs image processing on each of the received pieces of divided image data, and has an interface function for memory transfer.

[0044] The memory 980 temporarily stores the plurality of pieces of divided image data received for image processing. The controller transfer unit 950 performs image processing on each of the plurality of pieces of divided image data sequentially read from the memory 980, and then transfers the data from the receiving device 400 to the controller 910.

[0045] [First embodiment] <Functional configuration of transfer device 200> FIG. 3 is a block diagram illustrating an example of a functional configuration of the transfer device 200.

[0046] The transfer device 200 uses two channels, 0ch and 1ch, to perform high-speed serial transfer of a plurality of (here, two) pieces of divided image data obtained by dividing image data from the transmitting device 300 to the receiving device 400. Note that "ch" is an abbreviation for "channel."

[0047] First, a description will be given of the functional configuration of the receiving device 400. As shown in Fig. 3, the receiving device 400 includes a 0ch receiving unit 41, a 1ch receiving unit 42, a format conversion unit 43, a sub-scanning synchronization generation unit 44, a delay unit 45, a 0ch processing unit 46, a 1ch processing unit 47, a memory control unit 48, and a common image processing unit 49.

[0048] The 0ch receiving unit 41 receives the LVDS differential signal transmitted by the 0ch transmitting unit 35, and the 1ch receiving unit 42 receives the LVDS differential signal transmitted by the 1ch transmitting unit 36. The functions of the 0ch receiving unit 41 and the 1ch receiving unit 42 are each realized by an LVDS receiver circuit or the like.

[0049] The format conversion unit 43 sequentially converts the LVDS format received by each of the 0ch receiving unit 41 and the 1ch receiving unit 42 into image data, so that the downstream 0ch processing unit 46 and 1ch processing unit 47 can execute image processing. The format conversion unit 43 also has a function of absorbing asynchronous components that occur when, for example, a 60 MHz signal input from outside the transfer device 200 is frequency-modulated into a 200 MHz signal.

[0050] The sub-scanning synchronization generating unit 44 generates a sub-scanning synchronization signal and outputs it to each of the transmitting device 300 and the 0ch processing unit 46. The sub-scanning synchronization signal in the embodiment is a sub-scanning effective area signal that indicates the period from the start to the end of the effective area in the sub-scanning direction.

[0051] Here, there are two transmission paths for the sub-scanning synchronization signal generated by the sub-scanning synchronization generation unit 44: a first path 201 (thick dashed arrow) and a second path 202 (thick solid arrow). The sub-scanning synchronization signal includes a first sub-scanning synchronization signal and a second sub-scanning synchronization signal. The first sub-scanning synchronization signal is a signal that passes through the first path 201 in the receiving device 400 without passing through the transmitting device 300 and is input to the 0ch processing unit 46. The second sub-scanning synchronization signal is a signal that passes through the second path 202, which passes through the transmitting device 300, and is input to the 1ch processing unit 47.

[0052] In the first path 201, no particular processing is performed, and the first sub-scanning synchronization signal is input to the 0ch processing unit 46. Meanwhile, in the second path 202, after processing is performed in the pre-stage image processing unit 33 and the format conversion unit 43 in the transmitting device 300, the second sub-scanning synchronization signal is input to the 1ch processing unit 47. The input timing of the second sub-scanning synchronization signal is delayed relative to the first sub-scanning synchronization signal by the amount of these processes performed, resulting in a time lag due to the delay.

[0053] The delay unit 45 delays the input of the first sub-scanning synchronization signal input to the 0ch processing unit 46, thereby eliminating the delay of the second sub-scanning synchronization signal input to the 1ch processing unit 47 relative to the first sub-scanning synchronization signal, thereby compensating for the time lag between them. The delay can be compensated for by increasing or decreasing the number of lines, and the number of lines for compensating for the delay is determined in advance according to the time lag between the first sub-scanning synchronization signal and the second sub-scanning synchronization signal.

[0054] The 0ch processing unit 46 is an example of a first processing unit that performs image processing on the divided image data transferred using the 0ch system based on the first sub-scanning synchronization signal.

[0055] The 1ch processing unit 47 is an example of a second processing unit that performs image processing on the divided image data transferred using the 1ch system based on the second sub-scanning synchronization signal. The 1ch processing unit 47 performs image processing based on the second sub-scanning synchronization signal whose timing has been adjusted by the adjustment unit 34 in the transmitting device 300.

[0056] More specifically, the 0ch processing unit 46 executes image processing on the divided image data received by the 0ch receiving unit 41 while accessing the memory 980 via the memory control unit 48. The 1ch processing unit 47 executes image processing on the divided image data received by the 1ch receiving unit 42 while accessing the memory 980 via the memory control unit 48.

[0057] In cases where the color plates are different, the divided image data received by the 0ch receiving unit 41 and the divided image data received by the 1ch receiving unit 42 are subjected to different image processing depending on the color plate. By providing a 0ch processing unit 46 and a 1ch processing unit 47 for each channel, different image processing can be performed on the two divided image data. Examples of the image processing that is performed include image magnification processing, shading correction processing, and line-to-line correction processing.

[0058] After executing image processing, each of the 0ch processing unit 46 and the 1ch processing unit 47 outputs the processed divided image data to the memory control unit 48.

[0059] The memory control unit 48 performs access control and DMA (Direct Memory Access) for the memory 980. The divided image data is written to the memory 980 using a sub-scanning synchronization signal as a trigger, but when a sub-scanning synchronization signal with a size larger than the effective area is asserted, it is also possible to control so that unnecessary areas outside the effective area are not written to the memory 980.

[0060] The common image processing unit 49 executes common image processing on two divided image data of all color plates, etc.

[0061] On the other hand, the transmitting device 300 includes an image data generating section 31, a main scanning synchronization generating section 32, a front-stage image processing section 33, an adjusting section , a 0ch transmitting section 35, and a 1ch transmitting section .

[0062] The image data generating unit 31 converts the read analog data into digital data, and further converts it into the LVDS format.

[0063] The main scanning synchronization generating unit 32 generates a main scanning synchronization signal and outputs it to each of the pre-stage image processing unit 33 and the adjustment unit 34.

[0064] The front-stage image processing unit 33 distributes two pieces of split image data obtained by dividing the image data to the 0ch transmission unit 35 and the 1ch transmission unit 36. This distribution is performed for each color plate, for example, among color image data consisting of three colors, Red (R), Green (G), and Blue (B), R image data is distributed to the 0ch transmission unit 35, G image data to the 1ch transmission unit 36, and B image data to both the 0ch transmission unit 35 and the 1ch transmission unit 36. The front-stage image processing unit 33 can also be used when expanding the receiving device 400 by adding an image processing function that is not implemented in the receiving device 400.

[0065] The adjustment section 34 has a function of adjusting the timing of the second sub-scanning synchronization signal in accordance with a timing deviation of the second sub-scanning synchronization signal with respect to the main-scanning synchronization signal.

[0066] Specifically, the adjustment unit 34 detects the time offset of the second sub-scanning synchronization signal relative to the main-scanning synchronization signal based on the phase relationship between the assert edge of the main-scanning synchronization signal and the assert edge of the second sub-scanning synchronization signal, and adjusts the timing of the second sub-scanning synchronization signal in accordance with the timing offset.

[0067] More specifically, when the assert edge of the second sub-scanning synchronization signal is not detected within a predetermined detection period from the time when the assert edge of the main-scanning synchronization signal is detected, the adjustment unit 34 adjusts the latency of the second sub-scanning synchronization signal to delay it by one line, thereby adjusting the timing. Note that latency refers to the communication delay time that occurs from the time a transfer request is issued until the time when data is actually sent.

[0068] The specified detection period is determined by a delay that depends on the length of the wiring through which the second sub-scanning synchronization signal is transmitted through the second path 202, a delay that depends on the latency of the front-stage image processing unit 33 of the transmitting device 300, and the like.

[0069] If there is no timing deviation, i.e., if the assert edge of the second sub-scanning synchronization signal is detected within the specified detection period, the adjustment unit 34 outputs the second sub-scanning synchronization signal with a delay of a specified latency based on the conversion process in the image data generation unit 31. On the other hand, if there is a timing deviation, i.e., if the assert edge of the second sub-scanning synchronization signal is not detected within the specified detection period, the adjustment unit 34 outputs the second sub-scanning synchronization signal with a delay of one line further than the specified latency.

[0070] The 0ch transmission unit 35 transfers one of the two divided image data and the main scanning synchronization signal as an LVDS differential signal and transmits it. The 1ch transmission unit 36 ​​transfers the other of the two divided image data, the main scanning synchronization signal, and the second sub-scanning synchronization signal as an LVDS differential signal and transmits it.

[0071] One of the two channels is handled by a 0ch transmission unit 35, and the other is handled by a 1ch transmission unit 36. The functions of each of the 0ch transmission unit 35 and the 1ch transmission unit 36 ​​are realized by an LVDS transceiver circuit or the like.

[0072] <Example of Operation of Transfer Device 200> FIG. 4 is a timing chart illustrating an example of the operation of the delay unit 45 in the transfer device 200. As shown in FIG.

[0073] The upper part of Figure 4 shows the timing of the main scanning synchronization signal (for 0ch) 501, divided image data 502, and first sub-scanning synchronization signal (for 0ch) 503 input to the 0ch processing unit 46 in the 0ch system 50 based on the sub-scanning synchronization signal 500 generated by the sub-scanning synchronization generation unit 44 of the receiving device 400.

[0074] The lower part of Figure 4 shows the timing of the main scanning synchronization signal (for 1ch) 511, divided image data 512, and second sub-scanning synchronization signal (for 1ch) 525 input to the 1ch processing unit 47 in the 1ch system 51 based on the sub-scanning synchronization signal 500.

[0075] A main scanning synchronization signal (for 0ch) 501 and a main scanning synchronization signal (for 1ch) 511 each indicate the start timing of each line in the main scanning direction in the divided image data.

[0076] The divided image data 502 is composed of image data for each line in the period from an assertion edge 503a to an end time 503b when the first sub-scanning synchronization signal (for 0ch) 503 is in an effective state. The first sub-scanning synchronization signal (for 0ch) 503 in the period from the assertion edge 503a to the end time 503b is a sub-scanning effective area signal.

[0077] An assertion edge 503a in the first sub-scanning synchronization signal (for 0ch) 503 corresponds to a start time 500a of the sub-scanning synchronization signal 500 at the time of signal generation, and an end time 503b corresponds to an end time 500b of the sub-scanning synchronization signal 500. A delay time 504 occurs from the time the signal is generated by the sub-scanning synchronization generation unit 44 until it is input to the 0ch processing unit 46.

[0078] On the other hand, the divided image data 512 is composed of each line in the main scanning direction during the period from an assertion edge 525a when the second sub-scanning synchronization signal (for 1ch) 525 becomes valid to an end time 525b.

[0079] An assertion edge 525a in the second sub-scanning synchronization signal (for 1ch) 525 corresponds to a start time 500a of the sub-scanning synchronization signal 500 at the time of signal generation, and an end time 525b corresponds to an end time 500b of the sub-scanning synchronization signal 500. A delay time 514 occurs from the time the signal is generated by the sub-scanning synchronization generation unit 44 until it is input to the 1ch processing unit 47.

[0080] The delay time 514 in the 1ch system 51 occurs due to the processing in the pre-stage image processing unit 33 and the format conversion unit 43, etc., and due to asynchronous components accompanying frequency modulation, etc. On the other hand, the delay time 504 in the 0ch system 50 is generated by the delay unit 45. By adjusting the delay time 504 by the delay unit 45 so that the assert edge 503a and the assert edge 525a are aligned, the time lag between the input timing of the first sub-scanning synchronization signal to the 0ch processing unit 46 and the input timing of the second sub-scanning synchronization signal to the 1ch processing unit 47, which is caused by the path difference, is compensated for.

[0081] However, since the transmitting device 300 and the receiving device 400 operate asynchronously, depending on the phase relationship between the second sub-scanning synchronization signal (for 1ch) 525 output from the receiving device 400 to the transmitting device 300 and the main scanning synchronization signal (for 1ch) 511 generated by the transmitting device 300, the input timing of the second sub-scanning synchronization signal (for 1ch) 525 may be shifted due to path differences.

[0082] In other words, even if the time shift of the second sub-scanning synchronization signal (for 1ch) 525 caused by the path difference is compensated for by the delay unit 45, depending on the phase relationship between the second sub-scanning synchronization signal (for 1ch) 525 output from the receiving device 400 to the transmitting device 300 and the main scanning synchronization signal (for 1ch) 511 generated by the transmitting device 300, a line shift or the like may occur due to a shift in the input timing of the second sub-scanning synchronization signal (for 1ch) 525.

[0083] Figures 5 and 6 are timing charts for explaining such an input timing deviation of the second sub-scanning synchronization signal (for 1ch) 525. Figure 5 shows a case where there is no input timing deviation of the second sub-scanning synchronization signal (for 1ch) 525, and Figure 6 shows a case where there is an input timing deviation of the second sub-scanning synchronization signal 513. Figure 7 is a timing chart showing the action of adjustment unit 34 with respect to the input timing deviation of the second sub-scanning synchronization signal (for 1ch) 525.

[0084] 5 to 7, the second sub-scanning synchronization signal 513 input to the transmitting device 300 is generated by the sub-scanning synchronization generating unit 44 of the receiving device 400 and is input to the front-stage image processing unit 33 of the transmitting device 300. The main-scanning synchronization signal (for 1ch) 511 is a main-scanning synchronization signal generated by the main-scanning synchronization generating unit 32. The second sub-scanning synchronization signal (after synchronization) 523 is a sub-scanning synchronization signal after synchronization processing and speed conversion processing by the image data generating unit 31.

[0085] The main-scanning synchronization signal (common to 0ch and 1ch) 524 is a main-scanning synchronization signal common to the 0ch system and the 1ch system transmitted from the transmitting device 300. The second sub-scanning synchronization signal (for 1ch) 525 is a sub-scanning synchronization signal of the 1ch system transmitted from the transmitting device 300 to the receiving device 400 after timing adjustment by the adjustment unit 34. The divided image data (for 0ch) 526 is image data of the 0ch system transmitted from the transmitting device 300.

[0086] Further, the sub-scanning synchronization signal 500 in the receiving device 400 is a sub-scanning synchronization signal generated by the sub-scanning synchronization generating unit 44. The main-scanning synchronization signal (for 0ch) 501 is a main-scanning synchronization signal of the 0ch system input to the 0ch processing unit 46. The first sub-scanning synchronization signal (for 0ch) 503 is a sub-scanning synchronization signal of the 0ch system input to the 0ch processing unit 46. The divided image data (common to 0ch and 1ch) 534 is image data of the 0ch system input to the 0ch processing unit 46. The divided image data (for 1ch) 537 is image data of the 1ch system input to the 1ch processing unit 47.

[0087] Time lag 527 in the transmitting device 300 is a time lag of the second sub-scanning synchronization signal (for 1ch) 525 of the 1ch system that occurs with the processing of the front-stage image processing unit 33. Moreover, delay time 538 in the receiving device 400 is a delay time that occurs in the processing by the image data generating unit 31, delay time 539 is a delay time of the sub-scanning synchronization signal of the 0ch system generated by the delay unit 45, and delay time 540 is a delay time that occurs in the synchronization processing in the receiving device 400, for example, in the processing by the front-stage image processing unit 33.

[0088] The time lag between the assert edge 525 a of the second sub-scanning synchronization signal (for 1ch) 525 of the 1ch system and the assert edge 503 a of the first sub-scanning synchronization signal (for 0ch) 503 of the 0ch system is compensated for by the delay unit 45 .

[0089] However, depending on the phase relationship between the main scanning synchronization signal (for 1ch) 511 in the transmitting device 300 and the assert edge 513a of the input second sub-scanning synchronization signal 513, the input timing of the assert edge 525a of the second sub-scanning synchronization signal (for 1ch) 525 being transferred from the transmitting device 300 to the receiving device 400 may be shifted from the input timing of the assert edge 503a of the first sub-scanning synchronization signal (for 0ch) 503.

[0090] This timing difference between assert edge 525a and assert edge 503a occurs due to a delay in assert edge 523a of the second sub-scanning synchronization signal (after synchronization) 523 relative to the main-scanning synchronization signal (for 1ch) 511 due to synchronization processing and speed conversion processing by the image data generation unit 31.

[0091] In Fig. 5, the delay caused by the synchronization process and speed conversion process by the image data generation unit 31 is a predetermined delay time 528, so the input timing deviation does not occur. In Fig. 6, the delay caused by the synchronization process and speed conversion process by the image data generation unit 31 is a delay time 529 that is shorter than the predetermined delay time 528, so the input timing deviation 541 occurs (see the main scanning synchronization signal (for 1ch) 511 in the receiving device 400). This deviation 541 corresponds to an example of a timing deviation of the second sub-scanning synchronization signal 513 relative to the main scanning synchronization signal (for 1ch) 511.

[0092] The deviation 541 causes the lines of the divided image data corresponding to the color plates to be misaligned in the image processing performed by the 0ch processing unit 46 and the 1ch processing unit 47 of the receiving device 400, and as a result, an abnormal image may be output after image processing.

[0093] During image transfer, the CPU 960 has no way of knowing whether the second sub-scanning synchronization signal (for 1ch) 525 has shifted relative to the first sub-scanning synchronization signal (for 0ch) 503, and the CPU 960 cannot dynamically change the delay setting for the first sub-scanning synchronization signal (for 0ch) 503 of the receiving device 400.

[0094] 7, in this embodiment, when an assertion edge 513a of the second sub-scanning synchronization signal 513 is not detected within a predetermined detection period 532 from the main scanning synchronization signal (for 1ch) 511, the adjustment unit 34 determines that a shift 541 has occurred and adjusts the timing by delaying the second sub-scanning synchronization signal (for 1ch) 525 to be output to the receiving device 400 by an adjustment period 530 corresponding to one line. Then, the 1ch processing unit 47 executes image processing based on the second sub-scanning synchronization signal (for 1ch) 525 whose timing has been adjusted by the adjustment unit 34.

[0095] In the example of FIG. 7, the valid period of the divided image data (common to 0ch and 1ch) 534 is shifted by a period 531 from the assertion edge 503a of the first sub-scanning synchronization signal (for 0ch) 503 in the receiving device 400, but this shift does not affect the image quality.

[0096] However, the image data generating unit 31 is equipped with a line memory, and the adjustment unit 34 can further adjust the latency of the divided image data (common to 0ch and 1ch) 534 according to the detection result of the assert edge 525a of the second sub-scanning synchronization signal (for 1ch) 525 so as to align the ends of the effective areas in the second sub-scanning synchronization signal (for 1ch) 525 and the divided image data (common to 0ch and 1ch) 534. This makes it possible to delay the divided image data (common to 0ch and 1ch) 534 in the sub-scanning direction, and eliminate the deviation of the period 531 between the divided image data (common to 0ch and 1ch) 534 and the first sub-scanning synchronization signal (for 0ch) 503. Here, the divided image data (common to 0ch and 1ch) 534 is an example of a plurality of divided image data.

[0097] <Processing Example by Image Forming Apparatus 100> Next, a description will be given of a process performed by the image forming apparatus 100 including the transfer apparatus 200. FIG 8 is a flowchart showing an example of a process performed by the image forming apparatus 100.

[0098] First, in step S71, the image forming apparatus 100 determines whether or not the scanner unit 931 should start reading an original.

[0099] When it is determined in step S71 that reading is not to be started (step S71, No), the image forming apparatus 100 performs the process of step S71 again.

[0100] On the other hand, when it is determined in step S71 that reading is to be started (Yes in step S71), the image forming apparatus 100 causes the transmitting device 300 in the transfer apparatus 200 to execute the processes of steps S72 to S77, and causes the receiving device 400 to execute the processes of steps S79 to S84. The processes by the transmitting device 300 and the receiving device 400 are performed in parallel.

[0101] First, in step S72, the image data generating unit 31 in the transmitting device 300 converts the read analog data into digital data, and further converts it into the LVDS format.

[0102] Subsequently, in step S73, the main scanning synchronization generating unit 32 generates a main scanning synchronization signal (for ch0) 501 and a main scanning synchronization signal (for ch1) 511.

[0103] Subsequently, in step S74, the adjustment unit 34 determines whether the assertion edge 513a of the second sub-scanning synchronization signal 513 is detected within a predetermined detection period 532 from the main-scanning synchronization signal (for 1ch) 511 or not.

[0104] If it is determined in step S74 that the signal has been detected (Yes in step S74), the transmitting device 300 proceeds to step S76. On the other hand, if it is determined that the signal has not been detected (No in step S74), the adjustment unit 34 adjusts the timing in step S75 by delaying the second sub-scanning synchronization signal (for 1ch) 525 to be output to the receiving device 400 by an adjustment period 530 corresponding to one line.

[0105] Next, in step S76, the front-stage image processing unit 33 divides the image data input from the image data generating unit 31 into two divided image data 512, which are distributed to the 0ch transmitting unit 35 and the 1ch transmitting unit 36. Note that since the second sub-scanning synchronization signal 513 in the transmitting device 300 merely defines the effective area, the distribution and image processing of the divided image data 512 when the sub-scanning synchronization signal is negated may or may not be performed.

[0106] Next, in step S77, the 0ch transmission unit 35 and the 1ch transmission unit 36 ​​transmit the two divided image data 512, the main scanning synchronization signal (for 1ch) 511, and the second sub-scanning synchronization signal 513 as LVDS differential signals.

[0107] Next, in step S78, image forming apparatus 100 determines whether or not the transfer of image data of the valid area has been completed.

[0108] If it is determined in step S78 that the process is not complete (step S78, No), the sending device 300 and the image forming apparatus 100 perform the process from step S76 onwards again. On the other hand, if it is determined in step S78 that the process is complete (step S78, Yes), the image forming apparatus 100 ends the process.

[0109] On the other hand, in step S79, the sub-scanning synchronization generating unit 44 in the receiving device 400 generates a sub-scanning synchronization signal 500 and outputs it to the transmitting device 300 and the 0ch processing unit 46. Here, the generation of the sub-scanning synchronization signal 500 can be started at any timing. In general, it is started in conjunction with the transport of the document or the transport (scan) of the reading optical system.

[0110] Subsequently, in step S80, the delay unit 45 delays the first sub-scanning synchronization signal (for ch 0) 503 by a delay time 504 corresponding to a predetermined number of lines.

[0111] Next, in step S81, the 0ch receiving unit 41 and the 1ch receiving unit 42 receive the two divided image data 502, the main scanning synchronization signal (for 0ch) 501, and the second sub-scanning synchronization signal 513 by LVDS differential signals.

[0112] Next, in step S82, the format conversion unit 43 sequentially converts the received LVDS format into image data so that the downstream ch processing unit 46 and 1ch processing unit 47 can each execute processing.

[0113] The divided image data 502 transmitted from the transmitting device 300 may be transmitted in a data format that cannot be used for image processing as is due to parallel transmission of even-numbered line pixels and odd-numbered line pixels, etc. Therefore, it is preferable to appropriately rearrange the order of the pixels constituting the image data into a format that can be used for image processing.

[0114] Next, in step S83, the 0ch processing unit 46 executes image processing on the transferred divided image data 502 based on the first sub-scanning synchronization signal (for 0ch) 503. The 1ch processing unit 47 executes image processing on the transferred divided image data 502 based on the second sub-scanning synchronization signal (for 1ch) 525. Then, the 0ch processing unit 46 outputs the processed divided image data (for 0ch) 526 to the memory control unit 48, and the 1ch processing unit 47 outputs the processed divided image data (for 1ch) 537 to the memory control unit 48.

[0115] Next, in step S84, the common image processing unit 49 accesses the memory 980 via the memory control unit 48 and executes common image processing on the divided image data (for 0ch) 526 and the divided image data (for 1ch) 537.

[0116] Next, in step S85, image forming apparatus 100 determines whether or not the transfer of image data of the valid area has been completed.

[0117] If it is determined in step S85 that the process is not complete (step S85, No), the receiving device 400 and the image forming apparatus 100 perform the process from step S82 onwards again. On the other hand, if it is determined in step S85 that the process is complete (step S85, Yes), the image forming apparatus 100 ends the process.

[0118] In this manner, the image forming apparatus 100 can use the transfer device 200 to transfer the scanned document to the controller 910 of the image forming apparatus 100 or the like.

[0119] <Functions and Effects of Image Forming Apparatus 100> Next, the effects of the image forming apparatus 100 will be described.

[0120] In an image forming apparatus capable of transferring a plurality of divided image data pieces obtained by dividing image data from a transmitting device to a receiving device, a technique is known in which a synchronization signal is transmitted together with the plurality of divided image data pieces to synchronize the transferred plurality of divided image data pieces without adjustment using an analog signal. Also, a technique is disclosed in which a common sub-scanning synchronization signal generated by the transmitting device is utilized to synchronize the transferred plurality of divided image data pieces.

[0121] However, there are cases where it is necessary to synchronize the sub-scanning synchronization signal generated by the receiving device with the sub-scanning synchronization signal transmitted from the transmitting device, for example, when an existing device that can be linked with a document transport system or an optical transport system is used as the receiving device, and a new image processing function is added to the transmitting device for expansion.

[0122] By synchronizing using the sub-scanning synchronization signal generated by the receiving device and the sub-scanning synchronization signal transmitted from the transmitting device, there is an advantage that new functions can be added to the transfer device without making major changes such as changing parts that are linked to the document transport system or the optical transport system, etc.

[0123] However, in order to synchronize image data transferred between an existing receiving device and a transmitting device, it is necessary to use a common sub-scanning synchronization signal generated on the receiving device side, a sub-scanning synchronization signal that has passed through the transmitting device once and returned to the receiving device, and a sub-scanning synchronization signal transmitted within the receiving device. In this case, it becomes difficult to apply the conventional technology.

[0124] 9 is a block diagram showing an example of a functional configuration of a transfer device 200X according to a comparative example. For ease of explanation, the same reference numerals are used for components having the same functions as those of the functional configuration of the transfer device 200 shown in FIG.

[0125] Fig. 9 shows a path 201X along which a main-scanning synchronization signal and a sub-scanning synchronization signal generated by a synchronization signal generation unit 32X in the transmitting device 300X are transmitted to the receiving device 400. In addition to the path 201X, Fig. 9 also shows a path 202X along which a sub-scanning synchronization signal generated by a sub-scanning synchronization generation unit 44X in the receiving device 400X is input to each of the 0ch processing unit 46 and the 1ch processing unit 47.

[0126] In path 201X, the synchronization signal is generated only by the transmitting device 300X, so that the synchronization signal cannot be common to the transmitting device 300X and the receiving device 400X, making it difficult to synchronize the operation of the receiving device 400X and the document transport system linked to the receiving device 400X with the operation of the transmitting device 300X.

[0127] Furthermore, in the path 202X, since the synchronization signal is generated only by the receiving device 400X, the synchronization signal cannot be common to the transmitting device 300X and the receiving device 400X, and as with the path 201X, it becomes difficult to synchronize the operation of the receiving device 400X and the document transport system and the like linked to the receiving device 400X with the operation of the transmitting device 300X.

[0128] In the image forming apparatus 100 according to this embodiment, the receiving device 400 has a sub-scanning synchronization generation unit 44, a 0ch processing unit 46 (first processing unit), a 1ch processing unit 47 (second processing unit), and a delay unit 45. The transmitting device 300 has a main-scanning synchronization generation unit 32 and an adjustment unit 34. The 1ch processing unit 47 executes image processing (second processing) based on a second sub-scanning synchronization signal (for 1ch) 525 (second sub-scanning synchronization signal whose timing has been adjusted) whose timing has been adjusted by the adjustment unit 34.

[0129] By adjusting the delay time 504 by the delay unit 45, the time difference between the input timing of the first sub-scanning synchronization signal to the 0ch processing unit 46 and the input timing of the second sub-scanning synchronization signal to the 1ch processing unit 47, which is caused by the path difference, is compensated for.

[0130] Furthermore, by adjusting the adjustment period 530 by the adjustment unit 34, the input timing deviation 541 between the assertion edge 525a of the second sub-scanning synchronization signal (for 1ch) 525 and the assertion edge 503a of the first sub-scanning synchronization signal (for 0ch) 503 is compensated for.

[0131] For example, the adjustment unit 34 compensates for the input timing deviation 541 by adjusting the timing of the second sub-scanning synchronization signal 513 based on the phase relationship between the assertion edge 511a of the main-scanning synchronization signal (for 1ch) 511 and the assertion edge 513a of the second sub-scanning synchronization signal 513.

[0132] More specifically, the adjustment unit 34 adjusts the timing of the second sub-scanning synchronization signal 513 and compensates for the input timing deviation 541 by delaying the second sub-scanning synchronization signal 513 only when the assertion edge 513a of the second sub-scanning synchronization signal 513 is not detected within a predetermined detection period 532 from the assertion edge 511a of the main scanning synchronization signal (for 1ch) 511.

[0133] This makes it possible to synchronize the multiple divided image data 502 and 512 being transferred using a first sub-scanning synchronization signal (for 0ch) 503, which is input to the 0ch processing unit 46 without passing through the transmitting device 300, and a second sub-scanning synchronization signal 513, which is input to the 1ch processing unit 47 via the transmitting device 300, out of the sub-scanning synchronization signals 500 generated by the receiving device 400.

[0134] In the present embodiment, the functions of the transmitting device 300 and the receiving device 400 are implemented by electronic circuits such as ASICs, but the present invention is not limited to this. A part or all of the functions may be implemented by a processor such as the CPU 960 executing a predetermined program.

[0135] [Second embodiment] Next, an image forming apparatus 100a according to a second embodiment will be described. Note that the same components as those in the first embodiment are given the same reference numerals, and duplicated descriptions will be omitted as appropriate.

[0136] Here, the optimum value of the detection period 532 used for adjusting the timing of the second sub-scanning synchronization signal 513 by the adjustment unit 34 may differ depending on mechanical factors such as the dimensions of the image forming apparatus and the arrangement of components arranged in the image forming apparatus. Therefore, in this embodiment, the detection period 532 is made arbitrarily changeable.

[0137] 10 is a block diagram showing an example of a functional configuration of a CPU 960a included in the image forming apparatus 100a. As shown in FIG.

[0138] The accepting unit 961 accepts an operation input signal for changing the detection period 532 input by the user via the operation panel 940 , and outputs the signal to the changing unit 962 .

[0139] The change unit 962 changes the detection period 532 in response to an operation input signal from the reception unit 961. This operation input signal is an example of an external signal.

[0140] Fig. 11 is a flowchart showing an example of processing by the image forming apparatus 100a. Note that, since the processing of steps S93 to S107 in Fig. 11 is the same as the processing of steps S71 to S85 in Fig. 8, a duplicated description will be omitted here, and only the differences will be described.

[0141] First, in step S 91 , the receiving unit 961 receives an operation input signal for changing the detection period 532 , which is input by the user via the operation panel 940 , and outputs the signal to the changing unit 962 .

[0142] Subsequently, in step S 92 , the change unit 962 changes the detection period 532 in response to the operation input signal from the reception unit 961 .

[0143] In this manner, the image forming apparatus 100a can change the detection period 532 as desired.

[0144] The function of the change unit 962 may be realized by an electronic circuit such as an ASIC, but by using the CPU 960, it becomes possible to easily accommodate changes in function, etc.

[0145] Although the image forming apparatus according to the embodiment has been described above, the present invention is not limited to the above embodiment, and various modifications and improvements are possible within the scope of the present invention.

[0146] In the above-described embodiment, an example was shown in which image data read by the scanner unit 931 was transferred, but the present invention is not limited to this, and the embodiment can be applied to the transfer of various types of image data.

[0147] In the embodiment, the CPU 960 is provided separately from the CPU 901, but the functions of the CPU 960 may be integrated into the CPU 901.

[0148] The embodiment also includes an image data transfer method. For example, the image data transfer method is an image data transfer method by an image forming apparatus capable of transferring a plurality of divided image data obtained by dividing image data from a transmitting device to a receiving device, in which the receiving device performs a first process based on a first sub-scanning synchronization signal inputted without passing through the transmitting device among the sub-scanning synchronization signals, a second process based on a second sub-scanning synchronization signal inputted through the transmitting device among the sub-scanning synchronization signals, and a third process based on the second sub-scanning synchronization signal inputted through the transmitting device among the sub-scanning synchronization signals. and a delay step of delaying the first sub-scanning synchronization signal in accordance with a time difference between a first sub-scanning synchronization signal and the second sub-scanning synchronization signal, and the transmitting device includes a main-scanning synchronization generating step of generating a main-scanning synchronization signal that is a reference for synchronizing the multiple divided image data in a main-scanning direction perpendicular to the sub-scanning direction, and an adjusting step of adjusting the timing of the second sub-scanning synchronization signal in accordance with a timing difference between the main-scanning synchronization signal and the second sub-scanning synchronization signal, and the second processing step executes the second processing based on the second sub-scanning synchronization signal whose timing has been adjusted in the adjusting step. This image data transfer method can provide the same effect as the image forming apparatus described above. Such an image data transfer method may be realized by a CPU, a circuit such as an LSI, an IC card, or a standalone module, etc.

[0149] The embodiment further includes a program. For example, the program is a program that operates in an image forming apparatus capable of transferring a plurality of divided image data obtained by dividing image data from a transmitting device to a receiving device, in which the receiving device generates a sub-scanning synchronization signal that defines an effective area in a sub-scanning direction of the plurality of divided image data, executes a first process based on a first sub-scanning synchronization signal among the sub-scanning synchronization signals that is input without passing through the transmitting device, executes a second process based on a second sub-scanning synchronization signal among the sub-scanning synchronization signals that is input through the transmitting device, delays the first sub-scanning synchronization signal according to a time difference between the first sub-scanning synchronization signal and the second sub-scanning synchronization signal, the transmitting device generates a main-scanning synchronization signal that is a reference for synchronizing the plurality of divided image data in a main-scanning direction perpendicular to the sub-scanning direction, adjusts the timing of the sub-scanning synchronization signal according to a timing difference between the main-scanning synchronization signal and the second sub-scanning synchronization signal, and causes the computer to execute the second process based on the second sub-scanning synchronization signal whose timing has been adjusted. Such a program can provide the same effects as those of the image forming apparatus described above.

[0150] Each function of the above-described embodiments can be realized by one or more processing circuits. Here, the term "processing circuit" in this specification includes a processor programmed to execute each function by software, such as a processor implemented by an electronic circuit, and a device such as an ASIC (Application Specific Integrated Circuit), a DSP (digital signal processor), an FPGA (field programmable gate array), or a conventional circuit module designed to execute each function described above. [Explanation of symbols]

[0151] 100 Image forming device 200 Teleporter 201 Route 1 202 Route 2 300 Sending Device 31 Image data generation unit 32 Main scanning synchronization generator 33 Front-stage image processing unit 34 Adjustment part 35 0ch transmitter 36 1ch transmitter 400 Receiving Device 41 0ch receiver 42 1ch receiver 43 Format conversion section 44 Sub-scanning synchronization generator 45 Delay section 46 0ch processing unit (an example of a first processing unit) 47 1ch processing unit (an example of the second processing unit) 48 Memory control section 49 Common Image Processing Unit 500 Sub-scan sync signal 501 Main scan sync signal (for 0ch) 502, 512 Divided image data 503 1st sub-scanning sync signal (for 0ch) 504, 514 Delay Time 511 Main scan sync signal (for 1ch) 513 Second sub-scan sync signal 513a, 525a Assertion Edge 525 Second sub-scanning synchronization signal (for 1ch) (an example of a second sub-scanning synchronization signal whose timing has been adjusted by the adjustment unit) 527 Time lag 530 Adjustment Period 532 Detection Period 910 Controller 931 Scanner section 940 Operation Panel 950 Controller Transfer Unit 960 CPU 961 Reception 962 Changes 970 Reading Unit 980 Memory [Prior art documents] [Patent documents]

[0152] [Patent Document 1] JP 2006-080877 A

Claims

1. An image forming apparatus capable of transferring a plurality of divided image data obtained by dividing image data from a transmitting device to a receiving device, The receiving device: a sub-scanning synchronization generating unit that generates a sub-scanning synchronization signal that defines an effective area in a sub-scanning direction of the plurality of divided image data; a first processing unit that executes a first process based on a first sub-scanning synchronization signal inputted without passing through the transmitting device among the sub-scanning synchronization signals; a second processing unit that executes a second process based on a second sub-scanning synchronization signal input via the transmitting device among the sub-scanning synchronization signals; a delay section that delays the first sub-scanning synchronization signal in accordance with a time lag between the first sub-scanning synchronization signal and the second sub-scanning synchronization signal, The transmitting device: a main scanning synchronization generating unit that generates a main scanning synchronization signal serving as a reference for synchronizing the plurality of divided image data in a main scanning direction perpendicular to the sub-scanning direction; an adjustment unit that adjusts the timing of the sub-scanning synchronization signal input to the transmitting device in accordance with a timing difference between the main scanning synchronization signal and a sub-scanning synchronization signal among the sub-scanning synchronization signals that is input to the transmitting device; The adjustment unit outputs the second sub-scanning synchronization signal.

2. 2 . The image forming apparatus according to claim 1 , wherein the adjustment section adjusts the timing of the second sub-scanning synchronization signal based on a phase relationship between an assert edge of the main-scanning synchronization signal and an assert edge of the second sub-scanning synchronization signal.

3. 3. The image forming apparatus according to claim 1, wherein the adjustment unit delays the second sub-scanning synchronization signal only when an assertion edge of the second sub-scanning synchronization signal is not detected within a predetermined detection period from the assertion edge of the main-scanning synchronization signal.

4. The image forming apparatus according to claim 3 , further comprising a change unit that changes the detection period in response to an external signal.

5. The image forming apparatus according to any one of claims 1 to 3, wherein the adjustment unit further adjusts the latency of the multiple divided image data in accordance with the detection result of the assertion edge of the second sub-scanning synchronization signal so as to align the second sub-scanning synchronization signal with the ends of the effective areas in the multiple divided image data.

6. 1. An image data transfer method by an image forming apparatus capable of transferring a plurality of divided image data obtained by dividing image data from a transmitting device to a receiving device, comprising: The receiving device: a sub-scanning synchronization generating step of generating a sub-scanning synchronization signal that defines an effective area in a sub-scanning direction of the plurality of divided image data; a first processing step of executing a first process based on a first sub-scanning synchronization signal inputted without passing through the transmitting device, among the sub-scanning synchronization signals; a second processing step of executing a second process based on a second sub-scanning synchronization signal input via the transmitting device among the sub-scanning synchronization signals; a delay step of delaying the first sub-scanning synchronization signal in accordance with a time lag between the first sub-scanning synchronization signal and the second sub-scanning synchronization signal, The transmitting device: a main-scanning synchronization generating step of generating a main-scanning synchronization signal serving as a reference for synchronizing the plurality of divided image data in a main-scanning direction perpendicular to the sub-scanning direction by a main-scanning synchronization generating unit; an adjustment step of adjusting, by an adjustment unit, a timing of a sub-scanning synchronization signal input to the transmitting device in accordance with a timing difference between the main-scanning synchronization signal and a sub-scanning synchronization signal among the sub-scanning synchronization signals that is input to the transmitting device; The adjustment section outputs the second sub-scanning synchronization signal.

7. A program that operates on an image forming apparatus capable of transferring a plurality of divided image data obtained by dividing image data from a transmitting device to a receiving device, The receiving device: generating a sub-scanning synchronization signal that defines an effective area in a sub-scanning direction of the plurality of divided image data; performing a first process based on a first sub-scanning synchronization signal inputted without passing through the transmitting device among the sub-scanning synchronization signals; performing a second process based on a second sub-scanning synchronization signal input via the transmitting device among the sub-scanning synchronization signals; delaying the first sub-scanning synchronizing signal in accordance with a time lag between the first sub-scanning synchronizing signal and the second sub-scanning synchronizing signal; The transmitting device: a main scanning synchronization signal that serves as a reference for synchronizing the plurality of divided image data in a main scanning direction perpendicular to the sub-scanning direction is generated by a main scanning synchronization generating unit; an adjustment unit adjusts timing of the sub-scanning synchronization signal input to the transmitting device according to a timing difference between the main scanning synchronization signal and the sub-scanning synchronization signal input to the transmitting device among the sub-scanning synchronization signals; The adjustment unit outputs the second sub-scanning synchronization signal. A program that causes a computer to carry out processing.

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