JP6586900B2 - Image forming system, information processing apparatus, image forming apparatus, and image data transmission method - Google Patents

Description

  The present invention relates to an image forming system, an information processing apparatus, an image forming apparatus, and an image data transmission method, and more particularly to a technique for transmitting image data from an information processing apparatus such as a printer controller to the image forming apparatus.

  When noise enters the cable connecting the transmission side and the reception side, the checksum of the transmission data calculated on the transmission side and the checksum of the reception data calculated on the reception side do not match. The checksum is one of error detection codes, and the sum is obtained by regarding the data string as a string of integer values, and the remainder obtained by dividing this by a certain constant (surplus) is used as inspection data. Conventionally, when the checksum of transmission data and the checksum of reception data do not match, there is a technique in which transmission data is retransmitted from the transmission side to the reception side.

  A technique for generating such a checksum is described in Patent Document 1. Patent Document 1 states that “a divided data storage unit reads out encoded data stored in an encoded data area (301a), calculates a checksum for each predetermined size, and generates a code of a predetermined size corresponding to the calculated checksum. Are sequentially stored in the first area (311) of each packet data area (310a, 310b,...) Of the external memory (110), and the CPU executes the program to thereby divide the divided data. When the storage unit stores the block data and the checksum in the first area (311) of each packet data area, it sequentially reads the stored checksum, generates header information including the read checksum, and generates the checksum. It is stored in the second area (312) of the stored packet data area.

JP 2008-283394 A

  The prior art has caused an increase in transfer time due to retransmission of image data when the checksums do not match. In this retransmission, in addition to the original data transmission, data for which the checksums do not match are retransmitted, so that the transfer time is increased.

  The technique described in Patent Document 1 is to generate a checksum for each divided data (predetermined size encoded data) and transmit the divided data and the corresponding checksum for each divided data. However, Patent Document 1 does not mention the problems of the above-described conventional technology.

  The present invention has been made in consideration of the above situation, and an object thereof is to prevent an increase in transfer time even if image data is retransmitted when a transmission error occurs.

An image forming system of one embodiment of the present invention includes an information processing apparatus that transmits image data, and an image forming apparatus that receives the image data and performs image forming processing.
The information processing apparatus
A transmission-side feature data generation unit that divides image data for each line and generates first feature data indicating features for each line from the data for each line of the image data, and a first feature corresponding to the image data for each line A transmission processing unit that adds data and sequentially transmits each line.
In addition, the image forming apparatus
Data for each line of image data transmitted from the information processing device, a receiving unit for sequentially receiving first feature data corresponding to the data for each line, and data for each line of image data received by the receiving unit For each line of image data, a storage unit that sequentially stores, a reception-side feature data generation unit that generates second feature data indicating characteristics for each line from data for each line of image data stored in the storage unit, and A collation unit that collates the first feature data received from the information processing device with the second feature data generated by the reception-side feature data generation unit, and transmits a result of the collation to the information processing device. .
Then, the transmission processing unit of the information processing apparatus may be inconsistent when the collation result received from the image forming apparatus indicates that the first feature data and the second feature data do not match. The data of the line transmitted with the first feature data shown is transmitted as error line data overwriting the data of the other line at the transmission timing of the other line and retransmitted.

According to at least one aspect of the present invention, when a transmission error occurs, the data of the line (error line) indicating the mismatch of the input data is overwritten on the data of the other line at the transmission timing of the other line. And re-send. As a result, even if the input data (error line data) of the line where the transmission error has occurred is retransmitted, the transfer time does not increase, so the productivity does not decrease.
Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

1 is a system configuration diagram of an image forming system according to a first embodiment of the present invention. FIG. 3 is an operation explanatory diagram of the image forming system according to the first embodiment of the present invention. FIG. 2 is a block diagram illustrating a hardware configuration example of a printer controller according to the first embodiment of the present invention. FIG. 3 is a functional block diagram illustrating an internal configuration example of a printer controller according to the first embodiment of the present invention. 1 is a schematic diagram illustrating an example of the overall configuration of an image forming apparatus according to a first embodiment of the present invention. 1 is a block diagram illustrating a hardware configuration example of an image forming apparatus according to a first embodiment of the present invention. 2 is a functional block diagram of a control device in the image forming apparatus according to the first exemplary embodiment of the present invention. FIG. It is explanatory drawing of the transfer processing of the image data performed normally. It is explanatory drawing which shows the transfer process when the checksum of a transmission side and a receiving side corresponds, and the transfer process when a checksum does not correspond. It is explanatory drawing which shows the transfer processing example of the image data at the time of noise mixing which concerns on the 1st Embodiment of this invention. It is explanatory drawing which shows an example of the overwrite line list (table) which concerns on the 1st Embodiment of this invention. It is explanatory drawing which generalized the transfer processing of the image data at the time of the noise mixing which concerns on the 1st Embodiment of this invention. It is a sequence diagram which shows the example of a transfer process of the image data which concerns on the 1st Embodiment of this invention. FIG. 6 is a sequence diagram illustrating an example of restoration processing that is performed in the image forming apparatus after completion of image data transfer processing according to the first embodiment of the present invention. 4 is an explanatory diagram illustrating an example of image data stored in an image memory of the image forming apparatus according to the first exemplary embodiment of the present invention. FIG. It is a sequence diagram which shows the example of a transfer process of the image data which concerns on the 2nd Embodiment of this invention.

  Hereinafter, an example of an embodiment for carrying out the present invention will be described with reference to the accompanying drawings. In addition, in each figure, about the component which has the substantially same function or structure, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

<1. First Embodiment>
[Overall configuration of image forming system]
First, an image forming system according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2.
FIG. 1 is a system configuration diagram of an image forming system according to the first embodiment of the present invention.
FIG. 2 is an operation explanatory diagram of the image forming system according to the first embodiment of the present invention.

  The image forming system 1 includes a client terminal 2, a printer controller 3 (an example of an information processing apparatus), and an image forming apparatus 4 (an example of an image forming unit). The client terminal 2 and the printer controller 3 are connected by a communication line 5. The printer controller 3 and the image forming apparatus 4 are connected via a dedicated line 6 such as a video interface line. The communication line 5 is a network such as a LAN conforming to a standard such as Ethernet (registered trademark). In FIG. 1, the image forming apparatus 4 is connected to the communication line 5 via the printer controller 3, but the image forming apparatus 4 and the communication line 5 may be directly connected.

  The client terminal 2 transmits a print job 10 instructed to be printed by a user input operation to the printer controller 3 via the communication line 5. The print job 10 is data generated by the client terminal 2 in accordance with, for example, PDL (Page Description Language), and includes output settings and input data. For example, a personal computer (PC) is used as the client terminal 2.

  The printer controller 3 causes the image forming apparatus 4 to print out an image. The printer controller 3 receives a print job 10 from the client terminal 2 via the communication line 5. Then, the printer controller 3 executes rasterization processing (hereinafter described as RIP processing) on the input data extracted from the received print job 10, and the tag bit plane 11, Y plane 12y, M plane 12m, and C plane 12c. , K plane 12k is generated. The Y plane 12y, the M plane 12m, the C plane 12c, and the K plane 12k are bitmap data of cyan (C), magenta (M), yellow (Y), and black (K), respectively. Used as an example).

  The tag bit plane 11 is used to determine the object types of the Y plane 12y, the M plane 12m, the C plane 12c, and the K plane 12k. Then, the printer controller 3 transmits the tag bit plane 11 together with the Y plane 12y, the M plane 12m, the C plane 12c, and the K plane 12k to the image forming apparatus 4. In FIG. 1, the printer controller 3 is separate from the image forming apparatus 4, but the image forming apparatus 4 may be configured to incorporate the printer controller 3.

  The image forming apparatus 4 includes a print engine 41. The print engine 41 corresponds to the image forming unit 50 shown in FIGS. The print engine 41 performs appropriate image processing on each data of the Y plane 12y, the M plane 12m, the C plane 12c, and the K plane 12k based on the information of the tag bit plane 11 according to the output setting included in the print job 10. . Then, the print engine 41 performs processing (print output) of forming an image on the paper S (see FIG. 5 described later) and discharging the paper. The print engine 41 determines a tone curve type, a calibration type, a screen type, and the like according to the tag bit plane 11 when an image is formed on the paper S, and performs appropriate processing.

  The image forming system 1 may include at least the printer controller 3 and the image forming apparatus 4.

[Configuration example of printer controller]
FIG. 3 is a block diagram illustrating a hardware configuration example of the printer controller 3.
The printer controller 3 includes a control unit 30, an HDD 33, a communication I / F 34, and a printer I / F 35. The control unit 30 includes a CPU 31 and a memory 32.

The CPU 31 of the control unit 30 performs image processing such as RIP processing and control of the image forming apparatus 4.
The memory 32 of the control unit 30 temporarily stores data necessary for each process.
The HDD 33 records a program for the CPU 31 to perform RIP processing and control the image forming apparatus 4. The HDD 33 records input data, output settings, tag bit plane 11, Y plane 12y, M plane 12m, C plane 12c, and K plane 12k for each job. The functions of each unit shown in FIG. 4 to be described later are realized by the CPU 31 executing a program read from the HDD 33.
The communication I / F 34 performs data transmission / reception processing with the client terminal 2 via the communication line 5.
The printer I / F 35 performs data transmission / reception processing with the image forming apparatus 4 via the dedicated line 6.

FIG. 4 is a functional block diagram showing an example of the internal configuration of the printer controller 3.
The printer controller 3 includes a RIP processing unit 301, a buffer unit 302, a checksum calculation unit 303, a data transmission processing unit 304, an overwrite line list creation unit 305, and an overwrite line list 306.

  The RIP processing unit 301 performs rasterization processing (RIP processing) on input data (an example of image data) extracted from the print job 10 received from the client terminal 2, and executes a tag bit plane 11, a Y plane 12y, an M plane 12m, The C plane 12c and the K plane 12k (FIG. 2) are generated.

  The buffer unit 302 temporarily stores each input data (tag bit plane 11, Y plane 12y, M plane 12m, C plane 12c, K plane 12k) obtained by performing RIP processing on the input data in the RIP processing unit 301. It is a storage unit that accumulates. For the buffer unit 302, for example, a semiconductor memory is used.

  A checksum calculation unit 303 (an example of a transmission-side feature data generation unit) divides each input data temporarily stored in the buffer unit 302 for each line, and features each line from the data for each line of the input data. First feature data indicating is generated. Here, the checksum of each input data is calculated and used as the first feature data. The image forming apparatus 4 also calculates the second feature data (checksum) of each received input data.

  The data transmission processing unit 304 adds the first feature data corresponding to each line to the input data and sequentially transmits the input data to the image forming apparatus 4 via the dedicated line 6 for each line. Further, the data transmission processing unit 304 receives, from the image forming apparatus 4, a result of collating the first feature data with the second feature data generated by the image forming apparatus 4 for each line of each input data. To do. In addition, the data transmission processing unit 304 indicates that the first feature data and the second feature data generated by the image forming apparatus 4 are inconsistent. The data of the line transmitted with the one feature data is overwritten on the data of the other line at the transmission timing of the other line and retransmitted. In the following, the line transmitted with the first feature data indicated to be inconsistent will be described as an “error line”.

  In this embodiment, since each input data (tag bit plane 11, Y plane 12y, M plane 12m, C plane 12c, K plane 12k) is transmitted, the dedicated line 6 has at least five channels of transmission lines, and data The transmission processing unit 304 transmits each input data using five channels (see FIG. 8 described later). Note that, as a result of the verification, communication is performed using the channel for data A (tag bit plane 11), but the transmission path of the sixth channel may be used. Note that the transmission (transmission cycle) of input data is performed based on a synchronization signal having a predetermined frequency (for example, a clock signal from the CPU 71 or the like).

  The overwrite line list creation unit 305 registers the result of matching (history) indicating that the first feature data and the second feature data generated by the image forming apparatus 4 are inconsistent. 306 (see the table of FIG. 11 described later) is created. The overwrite line list 306 corresponds to a region where the correspondence between the error line (retransmission line) and another line (overwrite line) to which the data of the error line is retransmitted and the density in the image data is uniform. Line position information is registered. In FIG. 11, the base region is registered as a line corresponding to a region having a uniform density, but a solid region may be used instead of the base region. The base region is a region having a low density of 0% or close to 0%, and the solid region is a region having a high density close to 100% or 100%. The overwrite line list 306 is stored in the memory 32 or the HDD 33, for example.

[Configuration example of image forming apparatus]
FIG. 5 is a schematic diagram of an example of the overall configuration of the image forming apparatus 4.
The image forming apparatus 4 employs an electrophotographic system that forms an image using static electricity. For example, toner images of four colors of yellow (Y), magenta (M), cyan (C), and black (K) are used. Is a tandem type color image forming apparatus. The image forming apparatus 4 includes paper feed trays 20A and 20B, an image forming unit 50, an image input unit 61 including an automatic document feeder (ADF) 62, and an operation display unit 63. In addition, the image forming apparatus 4 includes a conveyance path 21 that conveys the paper S fed from the paper feed trays 20A and 20B or the manual feed tray. The transport path 21 is provided with a plurality of rollers (transport rollers) for transporting the paper S.

  The image forming unit 50 includes four image forming units 51Y, 51M, 51C, and 51K in order to form toner images of colors of yellow, magenta, cyan, and black. Each image forming unit 51 includes a charging unit (not shown), an LED writing unit 52 (laser light source), a developing unit, and a photosensitive drum 53 (see FIG. 6 described later). Further, the image forming unit 50 includes an intermediate transfer belt 54, a secondary transfer unit 55, and the like, onto which images formed on the photosensitive drums 53Y, 53M, 53C, and 53K of the image forming units 51Y, 51M, 51C, and 51K are transferred. A fixing unit 56 is provided downstream of the secondary transfer unit 55 in the sheet conveyance direction.

  On the downstream side of the fixing unit 56 in the paper conveyance direction, the conveyance path 21 extends and is connected to the paper discharge tray 66. In addition, a reverse conveyance path 22 that is branched downstream of the fixing unit 56 and joins the conveyance path 21 upstream of the secondary transfer unit 55 is connected to the conveyance path 21. A reversing unit 23 for reversing the sheet S is provided in the reversing conveyance path 22. The reversing unit 23 reverses the sheet S conveyed from the fixing unit 56 and conveys the sheet S to the conveyance path 21 on the upstream side of the secondary transfer unit 55 through the reversal conveyance path 22. Further, the reversing unit 23 can return the reversed sheet S to the transport path 21 on the downstream side of the fixing unit 56 and discharge it as it is.

  An operation display unit 63 is installed on the upper part of the image forming apparatus 4. The operation display unit 63 has a function as an operation unit that instructs the start of a job such as an image forming process. The operation display unit 63 is provided with a display unit 65 made of a liquid crystal panel or the like and an input operation unit 64 made of a touch panel or the like. On the display unit 65, it is possible to display the contents of operation by the user, setting information, and the like. The input operation unit 64 may be configured with a mouse, a tablet, or the like, and may be configured separately from the display unit 65.

  In the image forming mode, the image forming apparatus 4 charges the photosensitive drum 53 included in the image forming unit 51 of each color and exposes the surface of the photosensitive drum 53 in accordance with the document image. Form an image. Then, toner is attached to the electrostatic latent image on the photosensitive drum 53 corresponding to each of yellow, magenta, cyan, and black by using a developing unit to form a toner image of each color. Next, the toner images formed on the yellow, magenta, cyan, and black photoconductive drums 53 are sequentially primary-transferred onto the surface of the intermediate transfer belt 54 that is rotationally driven.

  Next, each color toner image primarily transferred onto the intermediate transfer belt 54 is secondarily transferred onto the paper S supplied from the paper supply unit 20 by the secondary transfer unit 55 (secondary transfer roller). Each color toner image on the intermediate transfer belt 54 is secondarily transferred to the paper S, thereby forming a color image. The image forming apparatus 4 discharges the sheet S on which the color toner image is formed to the fixing unit 56.

  The fixing unit 56 is a device that performs a fixing process on the paper S on which a color toner image is formed, which is supplied from the image forming apparatus 4. The fixing unit 56 pressurizes and heats the conveyed paper S to fix the transferred toner image on the paper S. The fixing unit 56 includes, for example, an upper fixing roller and a lower fixing roller that are fixing members. The upper fixing roller and the lower fixing roller are arranged in pressure contact with each other, and a fixing nip portion is formed as a pressing portion between the upper fixing roller and the lower fixing roller.

  A heating unit is provided inside the fixing upper roller. The roller part at the outer peripheral part of the fixing upper roller is heated by the radiant heat from the heating part. The sheet S is conveyed to the fixing nip so that the surface (fixed target surface) on which the toner image is transferred by the secondary transfer unit 55 faces the fixing upper roller. The sheet S passing through the fixing nip portion is pressed by the upper fixing roller and the lower fixing roller and heated by the heat of the roller portion of the upper fixing roller. The paper S on which the fixing process has been performed by the fixing unit 56 is discharged to the paper discharge tray 66.

(Control system for image forming apparatus)
FIG. 6 is a block diagram illustrating a hardware configuration example of the image forming apparatus 4.
As shown in FIG. 6, the image forming apparatus 4 includes an image forming unit 50, an image input unit 61, a control device 70, an image memory 81, a large capacity storage device 82, an image processing unit 83, a controller I / F 84, and an operation display unit. 63 and paper feed trays 20A and 20B.

  The control device 70 includes a CPU 71 (Central Processing Unit), a ROM 72 (Read Only Memory), and a work RAM 73 (Random Access Memory). The ROM 72 stores program data for controlling the entire image forming apparatus. The RAM 73 provides a storage area for work such as temporary storage of control commands such as image transfer processing. When the power is turned on, the CPU 71 reads out program data from the ROM 72 and starts up the system to control the entire image forming apparatus.

  The operation display unit 63 is connected to the CPU 71 described above, and is operated to input a paper type of the paper S on which an image is formed by the image forming unit 50 and image forming conditions such as image formation on one side or both sides. The operation display unit 63 is operated to input image density setting, paper size selection, copy number setting, and the like.

  The CPU 71 is connected to the control bus 75 and the data bus 76. A display unit 65 is connected to the data bus 76, and the display size of the image data acquired by the image input unit 61 is reduced and previewed, and selection items related to image generation conditions are displayed based on display data sent from the CPU 71. Or display. Note that the image forming conditions, paper feed cassette selection information, and the like set in the operation display unit 63 are output to the CPU 71 as operation data.

  A non-volatile memory 74 which is an example of a storage unit is connected to the CPU 71 via a control bus 75 and a data bus 76. In the nonvolatile memory 74, for example, data used when the control device 70 executes control is stored. The CPU 71 controls the image memory 81 or the like based on the image forming conditions set by the operation display unit 63, or a color image based on the image data Dy, Dm, Dc, Dk of each color processed by the image processing unit 83. The image forming unit 50 is controlled so as to form.

  An image input unit 61 is connected to the control bus 75 and the data bus 76 described above. The image input unit 61 is provided with an analog / digital converter (not shown). Based on the reading control signal, the image input unit 61 performs analog / digital conversion processing on analog image data obtained by reading from the document by the automatic document feeder 62 using an analog / digital converter. The image input unit 61 transfers the digital image data after analog / digital conversion to the image memory 81 connected to the control bus 75 and the data bus 76.

  The image data is temporarily stored in the image memory 81 based on the memory control signal. As the image memory 81, a semiconductor memory such as a DIMM (Dual Inline Memory Module) is used. A DIMM has a plurality of DRAM (Dynamic RAM) chips mounted on one or both sides of a plastic substrate. The CPU 71 outputs a reading control signal to the image input unit 61 via the control bus 75, and similarly outputs a memory control signal to the image memory 81. The CPU 71 controls writing and reading of data in the image memory 81, and reads image data from the image memory 81 (or the large capacity storage device 82) and transmits it to the image processing unit 83 during image formation.

  A mass storage device 82 is connected to the control bus 75 and the data bus 76. A hard disk or the like is used for the mass storage device 82. Under the control of the CPU 71, the large-capacity storage device 82 stores the image data temporarily stored in the image memory 81 in a predetermined area and reads the designated image data.

  Further, an image processing unit 83 is connected to the control bus 75 and the data bus 76. The CPU 71 outputs an image processing control signal to the image processing unit 83 via the control bus 75 to execute image processing control.

  The image processing unit 83 stores a three-dimensional color information conversion table in advance. The image processing unit 83 refers to the RGB color system image data read from the image memory 81 based on the image processing control signal, referring to the three-dimensional color information conversion table, and the YMCK color system image data Dy, Dm, Color conversion to Dc and Dk.

  The image processing unit 83 supplies image data to the LED writing unit 52 of each color of the image forming unit 50 in units of lines and in units of pixels. The image processing unit 83 uses a DSP (Digital Signal Processor), a RAM, or the like. The RAM is provided with a work area for supplying the image data D in line units and pixel units, and the image processed data is temporarily stored before being supplied to the image forming unit 50.

  The image forming unit 50 is connected to the control bus 75 and the data bus 76 described above. The image forming unit 50 includes the image forming units 51Y, 51M, 51C, and 51K shown in FIG. In FIG. 6, only the image forming unit 51Y for yellow is shown. The image forming unit 51Y constituting the image forming unit 50 includes an LED writing unit 52 in which a plurality of light emitters are arranged in a line, and a photosensitive drum 53 on which an image is formed by the LED writing unit 52. The other magenta, cyan, and black image forming units 51M, 51C, and 51K are the same as the image forming unit 51Y, and thus description thereof is omitted. In this example, the CPU 71 outputs an image formation control signal to the image forming unit 50 via the control bus 75.

  In the image forming unit 50, for example, the yellow LED writing unit 52 operates to input yellow image data D and image forming control signals in units of lines and form a yellow toner image on the photosensitive drum 53. To do. In the LED writing unit 52 for yellow, a group of laser beams for forming a yellow line for one line is generated at a time based on the image data D for one line. The laser beam group for yellow exposes one line of the photosensitive drum 53 at a time to form a line-shaped electrostatic latent image. The line-shaped electrostatic latent image formed on the photosensitive drum 53 is developed by the yellow toner member by the developing unit. The yellow toner image developed by the developing unit is transferred to the intermediate transfer belt 54.

  The paper feeder 20 is connected to the control bus 75, and the CPU 71 controls the paper feed trays 20A and 20B shown in FIG. 5 based on a paper feed control signal. The paper feed control signal is supplied from the CPU 71 to the paper feed unit 20. For example, the paper feed unit 20 selects one of the paper feed trays 20A and 20B based on the paper feed control signal, and transports the paper S fed from the paper feed tray 20A or 20B to the transport path 21 of the image forming unit 50. To do.

  A controller I / F 84 is connected to the data bus 76. A controller I / F 84 (an example of a data input unit) is connected to a dedicated line 6 such as a video interface line, and is used when the image forming apparatus 4 communicates with the printer controller 3. For example, the controller I / F 84 receives the image data transmitted from the printer controller 3 in units of lines and transfers the image data to the image memory 81 connected to the data bus 76 in units of lines.

[Function example of control device]
FIG. 7 is a functional block diagram of the control device in the image forming apparatus according to the first embodiment of the present invention. For example, the CPU 71 of the control device 70 reads out and executes the program from the ROM 72, thereby realizing the functions of the respective units shown in FIG.

  The control device 70 includes a data input unit 701, a checksum calculation unit 702, a collation unit 703, and a data restoration processing unit 704.

  A data input unit 701 (an example of a receiving unit) sends data for each line of input data transmitted from the printer controller 3 and first feature data corresponding to the data for each line via the controller I / F 84. Are sequentially received and temporarily stored in the image memory 81. Accumulation of input data is performed for each color plane (Y plane 12y, M plane 12m, C plane 12c, K plane 12k) and tag bit plane (tag bit plane 11).

  A checksum calculation unit 702 (an example of a reception-side feature data generation unit) generates second feature data indicating a feature for each line from the data for each line of each input data accumulated in the image memory 81. Similar to the checksum calculation unit 303 of the printer controller 3, the checksum calculation unit 702 calculates the checksum of each received input data and sets it as second feature data.

  The collation unit 703 sequentially collates the received first feature data and the second feature data generated by the checksum calculation unit 702 for each line of each received input data, and the result of the collation is The data is transmitted to the printer controller 3 via the I / F 84. If the input data becomes abnormal during transfer of the input data due to external noise or the like, the checksum becomes an error, and the result of the verification indicates a mismatch.

  When the input data abnormality occurs, the data restoration processing unit 704 performs restoration processing of each input data after the printer controller 3 has transmitted all the line data of each input data. As a premise of the restoration process, the data input unit 701 overwrites the data of another line from the printer controller 3 when the result of collation indicates that the first feature data and the second feature data do not match. Then, the retransmission data of the error line which is the retransmitted data is received. The data restoration processing unit 704 overwrites the error line retransmission data over the error line, which is retransmitted by overwriting the data of other lines after the data of all the lines of each input data is transmitted from the printer controller 3. To do. Then, the data restoration processing unit 704 restores each input data by rewriting the data of the other line with the data of the line corresponding to the region having a uniform density in the image data.

  The input data restored by the data restoration processing unit 704 is recorded from the image memory 81 to the mass storage device 82.

[Example of conventional image data transfer processing]
Next, image data transfer processing will be described.

(Normal image data transfer)
FIG. 8 is an explanatory diagram of image data transfer processing performed normally.
As shown in FIG. 8, the printer controller 3 uses the image forming apparatus for data Y, data M, data C, data K, and data A constituting a color image for each line synchronization signal HV (horizontal synchronization signal) in units of lines. Transfer to 4. When the data transmission for one page is completed, the process proceeds to data transmission for the next page by a page synchronization signal VV (vertical synchronization signal) (not shown). Data Y, data M, data C, data K, and data A correspond to the Y plane 12y, the M plane 12m, the C plane 12c, the K plane 12k, and the tag bit plane 11, respectively. FIG. 8 shows an example in which three lines of input data are transferred. The printer controller 3 sequentially transmits data D1 to D3 and first feature data C1 to C3 for each line (in this example, the first line to the third line).

(Image data transfer process according to verification result)
FIG. 9 is an explanatory diagram illustrating a transfer process when the feature data (checksum) on the transmission side and the reception side match and a transfer process when the feature data (checksum) do not match.

  In the image forming apparatus 4, the collation unit 703 confirms whether there is an abnormality in the input data received from the printer controller 3. The first line data D1 of the input data transmitted from the printer controller 3 is transferred to the image forming apparatus 4 together with the characteristic data C1 (checksum HVSUM (1)). The image forming apparatus 4 generates feature data (checksum) from the received first line data and compares it with the transmitted feature data C1 (checksum HVSUM (1)). As a result of the comparison, if the two match, the second line data D2 is transmitted from the printer controller 3 together with the feature data C2 (middle stage in FIG. 9). Conventionally, when the two do not match, the first line data D1 ′ is retransmitted along with the feature data C1 ′ on the second line, and the second line data D2 and the feature data C2 are transmitted on the third line. For this reason, an increase in transfer time due to retransmission has occurred.

(Example of image data transfer processing of the present invention)
FIG. 10 is an explanatory diagram showing image data transfer processing when noise is mixed according to the first embodiment of the present invention.

  If the image data becomes abnormal due to mixing of external noise while transferring input data, an error occurs in the checksum. The checksum error is notified from the image forming apparatus 4 to the printer controller 3, and the printer controller 3 performs a retransmission process. In the retransmission processing, for example, when noise is mixed in the first line, the data transmission processing unit 304, if the second line is a background area, transmits the abnormal data of the first line at the transmission timing of the second line. The second line data is overwritten and transmitted. The overwritten line position information (second line) is stored in the overwritten line list 306 by the overwritten line list creation unit 305. As described above, the overwrite line list 306 stores the retransmitted line position information together with the overwritten line position information, and further the background line position information.

  Next, at the transmission timing of the third line, the third line data D3 and the feature data C3 are transmitted as originally planned.

  Thereafter, the printer controller 3 transmits all input data to the image forming apparatus 4 and then transmits the overwrite line list 306 to the image forming apparatus 4. Based on the overwrite line list 306, the data restoration processing unit 704 of the image forming apparatus 4 uses the first line data D1 ′ (an example of retransmission data) retransmitted in the second line as the first line in which a checksum error has occurred. Overwrite the data in to restore the input data. After restoring the first line data, the data restoration processing unit 704 performs re-overwriting to return the overwritten line data to the original background data based on the overwrite line position information in the overwrite line list 306. The position of the original background data is registered in the overwrite line list 306. By this restoration processing, all input data to be transmitted by the printer controller 3 is restored.

[Overwrite line list example]
FIG. 11 shows an example of the overwrite line list (table) 306.
In this overwrite line list 306, the correspondence between the error line (retransmission line) where the check error has occurred and the other line (overwrite line) where the data of the error line is retransmitted, and the density in the input data are uniform. Position information of a line corresponding to a large area (background data or the like) is registered.

[Example of generalizing the image data transfer processing of the present invention]
FIG. 12 is a clear diagram that generalizes the transfer processing of image data when noise is mixed according to the first embodiment of the present invention. FIG. 12 shows an example in which the second line is not background data but the background data appears on the nth line.

  As shown in FIG. 12, when a checksum error occurs in the first line, if the next second line is background data, the first line data D1 of the first line in which the checksum error has occurred as shown in FIG. 'Is retransmitted. However, since the second line is not background data in FIG. 12, the second line data D2 and the feature data C2 are transmitted on the second line. Thereafter, when background data appears on the nth line, the first line data D1 ′ and feature data C1 ′ of the first line are retransmitted on the nth line.

[Image data transfer processing sequence]
Next, a transfer processing sequence when image data transfer processing is generalized will be described.
FIG. 13 is a sequence diagram showing an example of image data transfer processing according to the first embodiment of the present invention. The processing shown in FIG. 13 is realized by the CPU 31 of the printer controller 3 and the CPU 71 of the image forming apparatus 4 executing programs recorded in the HDD 33 and the ROM 72, respectively. Both the printer controller 3 and the image forming apparatus 4 perform this processing for each color.

  First, the data transmission processing unit 304 of the printer controller 3 sets the input data line variable n to ‘1’ (S <b> 1).

  Next, the data transmission processing unit 304 adds the first feature data (checksum) to the input data that has been subjected to the RIP processing by the RIP processing unit 301, and transmits the input data to the image forming apparatus 4 in line units (S2). . Here, the first line data and feature data are transmitted in the first line.

  Next, the data input unit 701 of the image forming apparatus 4 sequentially receives the input data line by line and stores it in the image memory 81 (S3).

  Next, the checksum calculation unit 702 generates second feature data (checksum) from the received line data of the input data (S4).

  Next, the collation unit 703 collates the first feature data sent from the printer controller 3 with the second feature data generated by the checksum calculation unit 702 (S5). Then, the collation unit 703 transmits the collation result to the printer controller 3 (S6).

  Next, the data transmission processing unit 304 of the printer controller 3 receives the collation result transmitted from the image forming apparatus 4 (S7). Next, the data transmission processing unit 304 determines whether or not the first feature data matches the second feature data based on the collation result (S8).

  If the collation result indicates that the first feature data matches the second feature data (YES in S8), the process proceeds to step S13.

  If the collation result indicates a mismatch between the first feature data and the second feature data (NO in S8), the process proceeds to step S9. Then, the data transmission processing unit 304 determines whether or not the next line is a background area (background data) (S9). As an example, whether or not the data of a certain line is background data is a value obtained by adding up the data string of the corresponding line of each color of Y, M, C, and K (for example, the ratio of printing to the entire input data (printing rate )).

  If the next line is not a base area (NO in S9), the process proceeds to step S13.

  If the next line is a background area (YES in S9), the data transmission processing unit 304 sets the error line data to be transmitted on the next line (S10), and proceeds to step S13.

  In parallel with the process of step S10, the data transmission processing unit 304 registers the position information of the line to be overwritten in the overwrite line list 306 together with the position information of the error line (retransmission line) (S11).

  Next, the data transmission processing unit 304 determines whether transmission of all input data has been completed (S12). When the number of lines of input data is N, transmission of all input data is completed when n ← N. If transmission of all input data has not been completed (NO in S12), the data transmission processing unit 304 proceeds to step S13.

  In the case of YES in step S8, in the case of NO in step S9, after the process in step S10, or in the case of NO in step S12, the data transmission processing unit 304 increments the variable n (n ← n + 1) ( S13). Here, the variable n is incremented to “2”.

  Then, the process proceeds to step S <b> 2, and the input data (second line data) of the next line is added with the corresponding first feature data (checksum) and transmitted to the image forming apparatus 4.

  Here, when transmission of all input data is completed in step S12 (YES in S12), the CPU 31 ends a series of processes.

[Image data restoration processing sequence]
Next, an image data restoration processing sequence will be described.
FIG. 14 is a sequence diagram illustrating an example of a restoration process performed in the image forming apparatus after completion of the image data transfer process according to the first embodiment of the present invention. The processing shown in FIG. 14 is realized by the CPU 31 of the printer controller 3 and the CPU 71 of the image forming apparatus 4 executing programs recorded in the HDD 33, the ROM 72, and the like.

  First, after transmitting all input data, the data transmission processing unit 304 of the printer controller 3 transmits the overwrite line list 306 to the image forming apparatus (S21).

  Next, the data input unit 701 of the image forming apparatus 4 receives the overwrite line list 306 from the printer controller 3 (S22). Then, the data input unit 701 notifies the data restoration processing unit 704 that the overwrite line list 306 has been received.

  Next, based on the information in the overwrite line list, the data restoration processing unit 704 overwrites the error line (retransmission line) with the retransmission data of the overwritten line (S23).

  Next, the data restoration processing unit 704 re-overwrites the base data on the line (for example, the base line) that has been overwritten by the retransmission data (S24). When this process ends, the data restoration processing unit 704 ends a series of processes.

FIG. 15 shows an example of image data stored in the image memory 81 of the image forming apparatus 4.
As described above, for example, a DIMM is used for the image memory 81, and a plurality of DRAM chips are mounted on one side or both sides of a plastic substrate. The image memory 81 of FIG. 15 includes a DRAM chip 81-1 on the front surface and a DRAM chip 81-2 on the back surface.

  Input data before restoration is recorded in the DRAM chip 81-1 on the first surface, and the DRAM chip 81-1 on the first surface is a work area. In the input data recorded in the RAM chip 81-1, an error line is generated on the first line, the first line data (retransmission data) is retransmitted on the second line, and the background data is transmitted on the nth line. It is.

  The input data after the input data of the first DRAM chip 81-1 is restored is recorded in the second DRAM chip 81-2. Here, the data restoration processing unit 704 overwrites the data on the first line with the first line data (retransmission data) retransmitted on the second line, and the nth line on the second line overwritten with the retransmission data. By overwriting the background data again, the restoration of the input data is completed. The restored input data is transmitted from the DRAM chip 81-2 to the mass storage device 82 and recorded in the mass storage device 82.

  According to the first embodiment described above, when a transmission error occurs, the data of the line (error line) indicating the mismatch of the input data is overwritten on the data of the other line at the transmission timing of the other line. And re-send. As a result, even if the input data (error line data) of the line where the transmission error has occurred is retransmitted, the transfer time does not increase, so the productivity does not decrease.

  When retransmitting, if the data of the line in which the transmission error has occurred is simply overwritten to the input data to be transmitted, the input data to be transmitted is not transmitted, so the image of the area corresponding to the overwritten line The image forming process is performed in a state where the image is missing. In this embodiment, when resending the input data of the error line, the input data of the overwriting destination line is set to a background area or a solid area having a uniform density, so that the image of the area corresponding to the overwritten line is restored. In this case, the original image can be restored to the same level. If the density of the overwriting destination line is uniform, the restoration accuracy can be maintained, and therefore, the data of the line corresponding to the uniform density area in the input data may be overwritten.

<2. Second Embodiment>
The second embodiment is an example of image data transfer processing when transmitting monochrome image data.

FIG. 16 is an explanatory diagram illustrating an example of image data transfer processing according to the second embodiment of the present invention.
In a monochrome image, since the color data channel is an empty channel, input data to be retransmitted is transferred using the empty channel. In the example of FIG. 16, channels of data K and data A are used, and channels of data Y, data M, and data C are vacant. Therefore, in the second line, in parallel with transmitting the second line data D2 and the feature data C2 of the data K and data A, the data K and the data A are utilized using the channels of the data Y, data M, and data C. The first line data D1 ′ and the feature data C1 ′ can be retransmitted.

  According to the second embodiment as described above, the data can be retransmitted on the line next to the line on which the transmission error has occurred, and therefore the overwrite line list 306 is unnecessary. In addition, the second embodiment has the same operational effects as the first embodiment.

  In the first and second embodiments described above, checksum data is generated as feature data for verifying input data in units of lines. However, if input data can be verified in units of lines, features generated by other methods are used. Verification may be performed using data.

  Furthermore, the present invention is not limited to the above-described embodiments, and various other application examples and modifications can be taken without departing from the gist of the present invention described in the claims. is there.

  For example, in the above-described embodiment, the configuration of the apparatus and the system is described in detail and specifically in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one having all the configurations described. . Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment. In addition, the configuration of another embodiment can be added to the configuration of a certain embodiment. Moreover, it is also possible to add, delete, and replace other configurations for a part of the configuration of each exemplary embodiment.

  Each of the above-described configurations, functions, processing units, processing means, and the like may be realized by hardware by designing a part or all of them with, for example, an integrated circuit. Each of the above-described configurations, functions, and the like may be realized by software by interpreting and executing a program that realizes each function by the processor. Information such as programs, tables, and files for realizing each function can be placed in a recording device such as a memory, a hard disk, or an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD.

  Further, the control lines and information lines indicate what is considered necessary for the explanation, and not all the control lines and information lines on the product are necessarily shown. Actually, it may be considered that almost all the components are connected to each other.

  Further, in this specification, the processing steps describing time-series processing are not limited to processing performed in time series according to the described order, but are not necessarily performed in time series, either in parallel or individually. The processing (for example, parallel processing or object processing) is also included.

  DESCRIPTION OF SYMBOLS 1 ... Image forming system, 3 ... Printer controller, 4 ... Image forming apparatus, 31 ... CPU, 32 ... Memory, 35 ... Printer I / F, 70 ... Control device, 71 ... CPU, 72 ... ROM, 73 ... RAM, 74 Non-volatile memory, 81 Image memory, 81-1, 81-2 DRAM chip, 82 Mass storage device, 83 Image processing unit, 301 RIP processing unit, 302 Buffer unit, 303 Checksum calculation , 304: Data transmission processing unit, 305 ... Overwrite line list creation unit, 306 ... Overwrite line list, 701 ... Data input unit, 702 ... Checksum calculation unit, 703 ... Verification unit, 704 ... Restoration processing unit, C1, C1 ', C2, C3 ... checksum data, D1, D1', D2, D3 ... line data

Claims (9)

In an image forming system comprising: an information processing apparatus that transmits image data; and an image forming apparatus that receives the image data and performs image forming processing.
The information processing apparatus includes:
A transmission-side feature data generation unit that divides the image data for each line and generates first feature data indicating the feature for each line from the data for each line of the image data;
A transmission processing unit that sequentially transmits the image data for each line by adding the first feature data corresponding to the line;
The image forming apparatus includes:
A receiver that sequentially receives the data for each line of the image data transmitted from the information processing apparatus, and the first feature data corresponding to the data for each line;
A storage unit for sequentially storing data for each line of the image data received by the reception unit;
A receiving-side feature data generation unit that generates second feature data indicating the feature of each line from the data of each line of the image data stored in the storage unit;
For each line of the image data, the first feature data received from the information processing device and the second feature data generated by the reception-side feature data generation unit are collated, and the result of the collation is obtained. A verification unit that transmits to the information processing device,
The transmission processing unit of the information processing device does not match when the result of the collation received from the image forming device indicates that the first feature data and the second feature data do not match. The data of the line transmitted with the first feature data indicated to be the error line data is overwritten on the data of the other line at the transmission timing of the other line and retransmitted. Image forming system. The transmission processing unit of the information processing apparatus re-transmits the error line data of the image data by overwriting data of a line corresponding to a region having a uniform density in the image data. Image forming system. The image forming apparatus further includes a restoration processing unit that performs restoration processing of the image data after data of all lines of the image data is transmitted from the information processing apparatus,
If the result of the collation indicates that the first feature data and the second feature data do not match, the receiving unit overwrites the data of the other line from the information processing device. Retransmit data of the error line that is retransmitted data,
The restoration processing unit, after the data of all the lines of the image data is transmitted from the information processing apparatus, retransmits the error line retransmission data overwritten on the data of the other lines and transmits the error line. 3. The image forming system according to claim 2, wherein the image data is restored by overwriting, and rewriting the data of the other line with data of a line corresponding to a region having a uniform density in the image data. The information processing apparatus registers a correspondence relationship between the error line and the other line to which the error line data is retransmitted, and position information of a line corresponding to a region having a uniform density in the image data. Overwritten line list, and
The transmission processing unit transmits the overwrite line list to the image forming apparatus after transmitting data of all lines of the image data,
The image forming system according to claim 3, wherein the restoration processing unit of the image forming apparatus performs the restoration processing of the image data based on information of the overwrite line list. The transmission-side feature data generation unit and the reception-side feature data generation unit calculate a checksum of the data for each line as the first feature data and the second feature data for each line of the image data. The image forming system according to claim 1. 6. The image forming system according to claim 1, wherein the region having a uniform density in the image data is a base region having the density of 0% or a solid region having the density of 100%. In an information processing apparatus that transmits image data used for image forming processing of an image forming apparatus,
A transmission-side feature data generation unit that divides the image data for each line and generates first feature data indicating the feature for each line from the data for each line of the image data;
A transmission processing unit that sequentially transmits the image data for each line by adding the first feature data corresponding to the line;
When the first feature data and the second feature data generated by the image forming apparatus are shown to be inconsistent, the transmission processing unit is shown to be inconsistent. An information processing apparatus that retransmits the data of the line to which the feature data of 1 is attached as error line data by overwriting the data of the other line at the transmission timing of the other line. In an image forming apparatus that receives image data from an information processing apparatus and performs image forming processing,
A receiving unit that sequentially receives data for each line of the image data transmitted from the information processing apparatus and first feature data indicating the characteristics for each line added to the data of the line;
A storage unit for sequentially storing data for each line of the image data received by the reception unit;
A receiving-side feature data generation unit that generates second feature data indicating the feature of each line from the data of each line of the image data stored in the storage unit;
For each line of the image data, the first feature data received from the information processing device and the second feature data generated by the reception-side feature data generation unit are collated, and the result of the collation is obtained. A verification unit for transmitting to the information processing apparatus;
The image forming apparatus includes a restoration processing unit that performs restoration processing of the image data after data of all lines of the image data is transmitted from the information processing apparatus,
When the result of the collation indicates that the first feature data and the second feature data do not match, the receiving unit transmits the other information at a transmission timing of another line from the information processing device. Receiving the retransmission data of the error line, which is the line transmitted with the first feature data indicated to be inconsistent, retransmitted by overwriting the data of the line,
The restoration processing unit, after the data of all the lines of the image data is transmitted from the information processing apparatus, retransmits the error line retransmission data overwritten on the data of the other lines and transmits the error line. An image forming apparatus that rewrites the data of the other line and rewrites the data of the other line with data of a line corresponding to a region having a uniform density in the image data to restore the image data. An image data transmission method in an image forming system comprising: an information processing apparatus that transmits image data; and an image forming apparatus that receives the image data and performs image formation processing,
A step of generating a first feature data indicating the feature of each line from the data of each line of the image data, wherein the transmission-side feature data generation unit included in the information processing apparatus divides the image data for each line; ,
A step in which a transmission processing unit included in the information processing apparatus sequentially transmits the image data for each line by adding the first feature data corresponding to the line;
A receiving unit included in the image forming apparatus sequentially receiving the data for each line of the image data transmitted from the information processing apparatus and the first feature data corresponding to the data for each line;
A storage unit included in the image forming apparatus sequentially stores data for each line of the image data received by the reception unit;
A reception-side feature data generation unit included in the image forming apparatus generates second feature data indicating the feature of each line from the data of each line of the image data stored in the storage unit;
The collation unit included in the image forming apparatus has the first feature data received from the information processing device and the second feature generated by the reception-side feature data generation unit for each line of the image data. Collating data and transmitting the collation result to the information processing apparatus;
When the transmission processing unit of the information processing apparatus shows that the result of the verification received from the image forming apparatus indicates that the first feature data and the second feature data do not match, The data of the line transmitted with the first feature data indicated to be the error line data is overwritten on the data of the other line at the transmission timing of the other line and retransmitted. And a method of transmitting image data.

Images