JP4379064B2 - Image processing apparatus and image forming apparatus - Google Patents

Description

The present invention is a tandem type image forming apparatus having an image forming unit by the number of the output color relates to an image processing equipment to be used in the image forming apparatus.

  For example, after a desired image processing is performed on an input color image, such as a printer, a facsimile machine, a copying machine, or a multi-function machine having a plurality of these functions, a color output image corresponding to this color image is output as a predetermined output. An image forming technique for forming on a medium is known.

For example, in the case of color output compatible image forming processing, RGB (or Lab (correctly L ^* a ^* b ^* )) image data obtained by reading a document or image data input from a personal computer or the like is output to the output side. Convert to a color signal suitable for subtractive color mixing. For example, at least three (preferably four) from the Lab color system represented by the Lab signal, for example, the YMC color system represented by each color signal of yellow (Y), magenta (M), and cyan (C) Mapping processing to a system or a CMYK color system with black (K) added thereto generates raster data that has been color-separated for print output. This raster data is sent to a print engine that forms a visible image corresponding to the read original image or an image input from a personal computer or the like on a printing paper. The print engine forms an image on printing paper of a predetermined size based on the received raster data.

  As the configuration of the engine unit that is a main part related to image formation, for example, a similar image forming process is repeated for each output color of K, Y, M, and C to form a color image. There is known a multi-pass type (cycle type) color image forming technique in which an image of each color is sequentially formed by a photoconductor unit, and a color image is formed by transferring the images one by one on an intermediate transfer member. . In this multi-pass color image formation processing technology, when a color image is output, it is necessary to perform image formation processing of each color in a frame sequential manner and transfer it onto an intermediate transfer member. It takes several times (four times in the previous example) time, and the output processing time FCOT (First Copy Out Time) from when the output command is issued until the output is discharged becomes long, resulting in poor productivity.

  In order to further shorten the output processing time FCOT at the time of color image output, a plurality of engines corresponding to each output color are arranged in an in-line manner (cascade arrangement) in the order of K → Y → M → C, for example. , Y, M, and C images are processed in parallel (simultaneously) by four engines in a tandem color image forming technique (see Patent Documents 1 and 2).

JP-A-8-65530 JP 2000-261676 A

  In the case of this tandem type color image forming technology, a plurality of engines corresponding to each output color are arranged at a predetermined interval (so-called tandem gap), and images corresponding to each output color are sequentially arranged at the time of image formation. It is necessary to pass to an engine corresponding to each output color at a predetermined interval. That is, it is necessary to absorb the difference in output timing due to each color data. For this reason, a buffer memory for holding an image in units of pages corresponding to each output color is required.

  For example, the input image data is converted into output color YMCK data by the color conversion unit, subjected to desired image processing, and stored in the buffer memory. The data in the buffer memory is sent to the corresponding output color image forming units at different timings for each YMCK. In this case, the reading timing from the buffer memory needs to coincide with the timing at which the data of the image forming unit is required. However, the operation timing of the YMCK image forming unit is different and the operation timing partially overlaps. Actually, it is not possible to match the timing of the image forming units for all colors. Therefore, it is necessary to provide a buffer memory for holding (buffering) data for each output color to absorb the difference in data output timing to the image forming unit. As described above, in the tandem type color image forming technology, not only the image forming unit is required for the number of output colors, but also a buffer memory for compensating for different image forming timings for each output color is required. There was a problem of incurring a cost increase.

  In order to solve this problem, for example, Patent Document 3 stores input data and simultaneously reads data in synchronization with the image formation timing of the image forming unit for each output color having different timing (time). By using a buffer memory that can be shared) and a color conversion unit that converts image data for each image forming unit, it is possible to reduce the difference in data output timing while keeping the capacity of the buffer memory small. Technology has been proposed.

JP 2000-59640 A

  However, the technique described in Patent Document 3 must control the data reading process from the buffer memory at a speed that is the number of output colors that is twice the normal speed (four times in the previous example). Can only be used for Therefore, the technique described in Patent Document 3 cannot be applied to a system that cannot handle high-speed reading processing. A system that can handle high-speed reading processing adopts a configuration that applies the technology described in Patent Document 3, and a system that cannot handle high-speed reading processing may adopt a configuration that applies conventional technology. It is done.

  However, an image processing unit (including a color conversion unit) that interfaces with a buffer memory is required for each low-speed and high-speed system, and a plurality of image processing units ( (Including a color conversion unit) must be prepared, resulting in redundant correspondence.

The present invention has been made in view of the above circumstances, and can reduce the capacity of the buffer memory, absorb the difference in data output timing caused by the tandem gap, and have various speeds and performances. the image forming apparatus capable of also suppressing the redundancy in the case corresponding to the system, as well, and an object thereof is to provide an image processing equipment to be used in the image forming apparatus.

That is, the image processing apparatus according to the present invention is an image processing apparatus used for a tandem image forming apparatus in which image forming units are arranged in cascade for the number of output colors, and is independent of the image forming unit. A pre-stage image processing unit that performs image processing on output device-independent data that is image data in space, and a color space that depends on the image forming unit for the processed output device-independent data processed by the pre-stage image processing unit A color conversion unit that converts the output device-dependent data that is the above image data, a post-stage image processing unit that performs image processing on the output device-dependent data obtained by the color conversion unit, output device-dependent data, and output device-independent an interface unit for selectively inputting and outputting the data has bidirectional data, it provided a pipeline processing function for switching the input and output data of the image processing path , The input of the data captured through the interface unit from any of the image processing blocks, was made comprising a path switching unit for performing switching processing for the output data of the corresponding subsequent Burokkuhe via the interface unit .

  The path switching unit outputs the output device-independent data from the interface unit, and takes the output device-independent data from the interface unit with a temporal difference corresponding to the tandem gap and passes it to the corresponding functional unit.

  An image forming apparatus according to the present invention is an image forming apparatus that forms a visible image on a predetermined output medium based on input image data, and that performs predetermined image processing on the input image data. The image processing apparatus according to the present invention is used as a unit, and an image forming unit that forms a visible image on a predetermined output medium based on processed image data processed by the image processing unit is provided. The number of output colors is as many as that of the tandem configuration that is arranged in cascade.

  A data storage apparatus according to the present invention includes an image processing apparatus according to the present invention that performs predetermined image processing on image data input from an input device such as a scanner, and image data processed by the image processing apparatus. And an image forming unit as an output device for forming a visible image on a predetermined output medium, and the image forming unit is used for a tandem type image forming apparatus provided for the number of output colors. In addition, the image forming unit has a storage unit that captures and holds output device-independent data, which is image data in an independent color space, from the image processing apparatus, and the data read from the storage unit is tandem as processing target data. A tandem gap correction processing function unit that performs gap correction processing is provided.

  The inventions described in the dependent claims define further advantageous specific examples of the image processing apparatus, the image forming apparatus, and the data storage apparatus according to the present invention.

According to the present invention, depending on the system configuration that uses the images processing device, either the data on the output device-dependent data and the other color spaces by input and output via the interface unit, an image processing path Can be switched adaptively.

  As a result, by using an image processing unit having a common architecture, it is possible to suppress the capacity of the buffer memory, absorb the difference in data output timing caused by the tandem gap, and suppress redundancy. However, it has become possible to build systems with various speeds and performance.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Configuration of copying machine>
FIG. 1 is a mechanism diagram of a copying apparatus (an example of an image forming apparatus) equipped with an image processing unit which is an embodiment of an image processing apparatus according to the present invention. The copying apparatus 1 roughly includes an image acquisition unit 10 that reads a document and acquires image data, an image processing unit 20 that performs desired image processing on the image data read by the image acquisition unit 10, and An image output unit 30 that forms an image corresponding to a document on a predetermined output medium based on the processed image processed by the image processing unit 20 and a platen cover 60 are provided. The image processing unit 20 is provided at a boundary portion between the image acquisition unit 10 and the image output unit 30.

  For example, the copying apparatus 1 can be connected to a network via a connection cable (not shown). For example, a CSMA / CD (Carrier Sense Multiple Access with Collision Detection) type LAN (Local Area Network; for example, IEEE 802.3) or a Gigabit (Giga Bit) based LAN (hereinafter collectively referred to as a wired LAN) connects to an image input terminal. Is done. As an image input terminal, for example, an arbitrary number of image input sources such as a personal computer, a color scanner, a digital camera, or a data storage device such as a hard disk device, a magneto-optical disk device, or an optical disk device for processing such as document creation and editing are used. May be included. Each of these terminal devices incorporates an application program for creating a document. The image input terminal inputs a document to the copying apparatus 1.

  The copying apparatus 1 is not limited to an apparatus that obtains an image as electronic data from these image input terminals. For example, the copying apparatus 1 is a device that has a communication function for obtaining an image as electronic data via a communication network (not shown). Also good. For example, it is connected to an image input terminal such as a FAX apparatus via a public switched telephone network (PSTN). Note that facsimile data may be exchanged using ISDN (Integrated Switched Digital Network) or other communication media including the Internet instead of the general subscriber telephone network PSTN.

  The copying apparatus 1 is, for example, an IEEE (Institute of Electrical and Electronics Engineers, Inc.) 1394 standard device 3f or a USB (Universal Serial Bus; 1.1 or 2.0) standard device. Connection is possible, and digital image data can be received from these devices. Alternatively, the copying apparatus 1 can be controlled remotely via these devices.

  As described above, the copying apparatus 1 forms an image based on image data from various image input terminals (prints and outputs it) as well as a copying function for forming a copy of a document read by the image acquisition unit 10. For example, a so-called multi-function machine (multifunction machine) having a page printer function and a facsimile transmission / reception function is configured as a digital printing apparatus. At this time, for example, a system may be constructed using a part of the functions of the image processing unit 20. In addition, while using a plurality of image processing units 20 having similar functions, the internal functional modules are used properly according to the functional purposes of the system configuration, or the same functional units are used so as to perform different functions. May be. For these points, it is preferable to refer to the description of the apparatus configuration development described later.

  The image acquisition unit 10 emits light toward a surface (back surface) opposite to the document placement surface of the platen glass 11 below a platen glass (document placement table) 11 made of transparent glass provided on the housing. The light source 12 to irradiate and the substantially concave reflection shade 17 which reflects the light emitted from the light source 12 to the platen glass 11 side are provided. The image acquisition unit 10 receives reflected light from the platen glass 11 side and performs a main scan FS (Fast Scan) that is substantially orthogonal to the direction of the sub-scan SS (Slow Scan) (the reading direction of the arrow X1 in the figure). A light receiving unit 13 that sequentially reads an image in a direction (depth direction in the drawing) and sequentially outputs an image signal (analog electric signal) corresponding to the density, and amplifies and outputs the image signal from the light receiving unit 13 to a predetermined level. The contact optical system includes a signal processing unit 14. The light receiving unit 13 is disposed on the substrate 15 together with the signal processing unit 14 and the like, and constitutes an optical scanning system (sensor unit) 16.

  Although not shown, the image acquisition unit 10 also includes a drive motor such as a wire, a drive pulley, or a stepping motor for moving the light source 12, the light receiving unit 13, the signal processing unit 14, and the like under the platen glass 11. Provided in the body. The driving pulley is reciprocally rotated by the driving force of the driving motor, and the wire is wound around the driving pulley by the rotation driving. As a result, the light receiving unit 13 and the like are configured to be able to reciprocate integrally below the platen glass 11 in the sub-scanning SS direction (arrow X1 in the figure) and in the opposite direction (arrow X2 in the figure). . In addition, the read image is enlarged or reduced (magnified) in the sub-scanning direction by changing the relative movement speed between the optical scanning system (sensor unit) 16 and the original as compared with normal reading (100% output). It is also possible.

  The image acquisition unit 10 converts an input image obtained by reading a document placed on the platen glass 11 into digital image data R, G, and B of red, green, and blue color components and inputs the digital image data to the signal processing unit 14. To do. The signal processing unit 14 amplifies the red, green, and blue image signals from the light receiving unit 13 to a predetermined level by an amplification unit (not shown), and further converts the image signal into digital data by an A / D converter (not shown). , Green and blue digital image data R, G, B are output from the A / D converter. The red, green, and blue image data R, G, and B are sent to the image processing unit 20 through the cable 19.

  The image output unit 30 has a tandem configuration in which image forming units (transfer units / printing engines) 31 of output colors Y, M, C, and K arranged side by side sequentially in one direction are arranged in cascade. Is. In the following, each of the image forming units 31 of each color is denoted by reference symbols Y, M, C, and K, and the color symbols are omitted when collectively referred to. The same applies to other members.

  In the illustrated example, four output colors Y, M, C, and K are used. However, the present invention is not limited to this. For example, more outputs such as gray (gray) Gy as the fifth color are used. It may include a color or may be three colors of Y, M, and C excluding black (K). In the illustrated example, the arrangement order of the image forming units 31Y, 31M, 31C, and 31K corresponding to the output colors Y, M, C, and K is Y → M → C → K, but is not limited thereto. Other arrangement orders such as K → Y → M → C may be used.

  A photosensitive drum 32 is disposed at the center of the image forming unit 31, and a primary charger 33, a developing unit 34, a transfer charger 35, and the like are disposed around the photosensitive drum 32. A writing scanning optical system such as a polygon mirror 39 for recording a latent image on the photosensitive drum 32 based on the formation data is provided.

  The image output unit 30 includes a paper cassette 41 and a conveyance path 42 for conveying the printing paper to the image forming unit 31. A leading edge detector 44 is provided in proximity to a conveyance path 42 for printing paper conveyed from the paper cassette 41 to each image forming unit 31. The leading edge detector 44 optically detects, for example, the leading edge of the printing paper fed onto the transfer belt (conveyance belt) 43 through the registration roller 42 a to obtain a leading edge detection signal, and this leading edge detection signal is sent to the image processing unit 20. send.

  The image processing unit 20 that functions as a post image processing unit synchronizes with the tip detection signal input from the image output unit 30, and displays red, green, and blue images from the signal processing unit 14 of the image acquisition unit 10. After predetermined image processing is performed on the data R, G, and B, Y, M, C, and K image formation data (for example, on / off binarized toner signal) is obtained, and the processed Y, M, C, and K are processed. Are sequentially input to the image output unit 30 at regular intervals (so-called tandem gap).

  In the image output unit 30, first, the semiconductor laser 38Y as a light source for forming a latent image is driven by yellow (Y) image formation data from the image processing unit 20, thereby converting the yellow image formation data into an optical signal. The converted laser beam is irradiated toward the polygon mirror 39. The laser light further scans the photosensitive drum 32Y charged by the primary charger 33Y via the reflection mirrors 47Y, 48Y, and 49Y, thereby forming an electrostatic latent image on the photosensitive drum 32Y. The electrostatic latent image is converted into a toner image by a developing device 34Y to which yellow toner is supplied. The toner image is transferred to a sheet by a transfer charger 35Y while the sheet on the transfer belt 43 passes through the photosensitive drum 32Y. Transcribed above. After the transfer, excess toner is removed from the photosensitive drum 32Y by the cleaner 36Y.

  For each of the M, C, and K colors, electrostatic latent images are sequentially formed on the photosensitive drums 32M, 32C, and 32K in the same manner as the Y color. Each electrostatic latent image is sequentially converted into a toner image by developing units 34M, 34C, and 34K to which toner of each color is supplied. Each toner image is sequentially transferred onto the paper by the corresponding transfer chargers 35M, 35C, and 35K while the paper on the transfer belt 43 passes through the corresponding photosensitive drums 32M, 32C, and 32K. As described above, the sheet on which the toner images of each color of Y, M, C, and K are sequentially transferred is peeled off from the transfer belt 43, the toner is fixed by the fixing roller 45, and discharged to the outside of the copying machine. The

  Note that the configuration of the image output unit 30 is not limited to that described above, and may be, for example, an intermediate transfer IBT (Intermediate Belt Transfer) system including one or two intermediate transfer belts.

<Configuration of image processing unit>
FIG. 2 is a circuit block diagram of an embodiment of the image processing unit 20 that functions as a main image processing apparatus provided in the copying apparatus 1 having the above configuration. In the image processing unit 20, red, green, and blue image data R, G, and B are input from the image acquisition unit 10 (signal processing unit 14). Alternatively, the image data L is converted into image data L, a, and b in a Lab color space (correctly L ^* a ^* b ^* ) which is a device-independent color space by a pre-stage color conversion unit (not shown). , A, b are input. In the following description, it is assumed that the image data L, a, and b are input to the image processing unit 20.

  Hereinafter, the outline of each functional part constituting the image processing unit 20 will be described, and the data path switching function which is a characteristic part of the present embodiment will be described in detail later. In the following description, “D” indicating that the image data is image data, a reference code of the functional part, and a reference code of each color information are sequentially attached to the image data output from each functional part. Will be shown. In addition, when the plurality of color signals are collectively referred to, “D” indicating image data, a functional part reference code, and all color information reference codes are sequentially attached. . For example, the brightness data L output from the image acquisition unit 10 is D10L, the chromaticity data a and b are D10a and D10b, and these are collectively D10Lab.

  As shown in the figure, the image processing unit 20 is roughly divided into a front image processing unit 20a, a rear image processing unit 20b, and a peripheral part. Peripheral portions of the present embodiment include a first path switching unit 801, a clock generation unit (CLK) 806, and a host IF (HOST I / F) that takes a data interface with an external device using a technique such as DMA transfer. Part 900 is provided.

  The first path switching unit 801 is a pre-stage switching unit 801a that is an example of a processing target image input unit provided on the left side in the figure, an intermediate switching unit 801b provided in the center part in the figure, and a process provided on the right side in the figure. A post-stage switching unit 801c, which is an example of a completed image output unit, and a connection unit 801d connecting them. Each of the upstream switching unit 801a, the intermediate switching unit 801b, and the downstream switching unit 801c includes a connection interface unit that takes a data interface with the outside. For example, it has an input buffer and an output buffer. The pre-stage image processing unit 20a and the post-stage image processing unit 20b are divided by an intermediate switching unit 801b extending from above in the center of the first path switching unit 801 in the drawing.

  Each functional unit of the first path switching unit 801 has data bidirectionality, and has a pipeline processing function for switching input / output data of an image processing path according to a set register value. A switching process is performed in which a plurality of input data is output to the corresponding subsequent block. In particular, as a characteristic part of the image processing unit 20 of the present embodiment, an output device is connected to a device (for example, a data storage device that performs a tandem gap correction function, an electronic sort function, or the like) connected to the outside by the intermediate switching unit 801b. The dependency data and image data in a color space different from the color space depending on the image forming unit can be selectively used.

  Thereby, it is possible to construct a plurality of systems with an image processing unit having a common architecture, and for example, it is possible to deal with systems of various speeds and configurations. When realizing the image path switching function by the first path switching unit 801, the process of setting the register value of the first path switching unit 801 can be executed by a hardware switch, but can also be set by software. Preferably, both input device dependent data (RGB data in this example) dependent on the image acquisition unit 10 as an input device and output device dependent data (YMCK data in this example) dependent on the image forming unit 31 are used. Independent device-independent data (Lab data in this example) and output device-dependent data (YMCK data in this example) can be selectively used.

  For example, 8-bit image data (Lab and RGB 3 systems) captured in the upstream switching unit 801a is directly used in the upstream image processing unit 20a, and 8-bit image data captured in the intermediate switching unit 801b is directly processed in the downstream image processing unit. Furthermore, the processed image data (four YMCK systems; 8-bit, binary, or quaternary) fetched by the post-stage switching unit 801c can be passed to the image output unit 30 as it is. Further, it is also possible to send the image data taken into the intermediate switching unit 801b to the subsequent switching unit 801c as it is via the connection unit 801d and to pass it to the image output unit 30 side. In addition, it is also possible to pass the image data fetched into the subsequent switching unit 801c to the intermediate switching unit 801b or the previous switching unit 801a via the connection unit 801d. It is also possible to send 10-bit image data captured by the upstream switching unit 801a to the downstream switching unit 801c as it is via the connection unit 801d and pass it to the image output unit 30 side.

  Furthermore, by inputting and outputting image data at the lower part of the intermediate switching unit 801b in the drawing, it is possible to bypass the image path and perform desired processing outside the image processing unit 20. Details of the detour processing and the path route of the image data at that time will be described later.

  The upstream image processing unit 20 a includes a upstream filter processing unit 106 and a scaling processing unit 200.

  The post-stage image processing unit 20b is a color conversion unit 500 that converts an input color signal into another color signal system, a post-stage filter processing unit 300, a post-stage color adjustment unit 600, and image data for the image output unit 30 (for example, 2 And an output data processing unit 700 that generates (valued data) in this order.

  Each functional unit in the latter-stage image processing unit 20b has a function of an adaptive process execution unit that performs an adaptive process according to the characteristics of an image object such as a character / photo / halftone dot with reference to tag data. Here, in the configuration of the present embodiment, the subsequent filter processing unit 300 and thereafter, that is, between the color conversion unit 500 and the output data processing unit 700 includes color image processing blocks (Y, M, C; K). Or a processing block (K) for monochrome images, regardless of whether the document read by the image acquisition unit 10 is a color document or a monochrome document (typically a monochrome document). Instead, each processing block processes in parallel.

  The output data processing unit 700 uses the color image data Y, M, C, and K and the monochrome image data LL as input data, and screen-processed image formation data (for example, binarized data) for each tandem gap. Are output to the image output unit 30 side at regular intervals (with a temporal difference corresponding to the tandem gap). Alternatively, the color image data Y, M, C, K and the monochrome image data LL are output simultaneously. Each color can be operated at an independent timing, and an error diffusion function and a packing function are exclusively selected / functioned.

  As an error diffusion function, 8-bit image data is input and binarized data or multilevel data subjected to error diffusion processing is output. For example, the color image data Y, M, C, and K are provided with a 2-bit adaptive error diffusion processing function and a 4-bit error diffusion processing function, and are output using the selected processing. On the other hand, the monochrome image data LL has only a 2-bit adaptive error diffusion processing function. Here, the 2-bit adaptive error diffusion processing function operates as 1-bit adaptive error diffusion by setting all three levels of quantization thresholds to the same value. The 4-bit error diffusion processing function operates as dither by setting all error filter values to “0”.

  Based on the input pixel synchronization signal (pixel synchronization clock) VCLK, the clock generation unit 806 generates an input clock frequency and a frequency twice that frequency by an internal PLL (not shown), and functions as a pre-image processing unit. 14 or the image processing unit 20 itself functioning as a post image processing unit is supplied with either frequency. Which frequency can be set by a register. In addition, it is preferable to design so that it is not necessary to perform reset processing after frequency switching.

  The host IF unit 900 captures image data from the outside of the copying apparatus 1 by DMA transfer, generates various control signals, passes them to a desired functional part via the local bus in the image processing unit 20, and performs desired processing. It has a function to let you. For example, an 8-bit input / output port is incorporated. Also, the address data is decoded and a chip select signal for the internal block is generated. Also, the register value of the first path switching unit 801 is set. Accordingly, various types of copying apparatuses 1 can be configured by properly using internal function units according to the purpose (see FIGS. 5 to 12 to be described later).

  When the image processing unit 20 having the above configuration is connected to a PCI (Peripheral Component Interconnect) bus, it is realized by using a PCIIF unit with a burst function at 32 bits / 33 MHz. In addition, the image processing unit 20 having the above configuration can be configured as a semiconductor device such as an ASIC (Application Specific IC). In this case, the connection to the PCI bus as described above is realized by using an FPGA (Filed Programmable Gate Alley: Field Programmable Gate Array) having the PCIF function with a burst function.

<Cooperation between image processing unit and other connected devices (basic)>
3 to 5 are diagrams for explaining a cooperation method between the image processing unit 20 illustrated in FIG. 2 and another connected device. 3 and 4 show examples of the basic configuration of the copying apparatus 1 when an option (IIT option) of an image acquisition unit (IIT) is used as a connection device, and FIG. 5 shows a sort processing unit. 2 shows an example of the basic configuration of the copying apparatus 1 in the case where is a connection device. It is assumed that the image processing unit 20 used in each drawing is configured by an ASIC.

  In the first basic configuration shown in FIG. 3, the image is rotated on the IIT option board 24 based on the image data Lab from the image acquisition unit 10 side (color conversion on the previous stage side is completed), and if necessary Further, the image processing unit (C) 26 for enlarging or reducing is provided. Details of the function of the image processing unit 26 will be described later. The image processing unit 26 has a configuration that can be selectively used as needed by image path switching control by the first path switching unit 801.

  The path route of image data when using the image processing unit 26 is as follows. That is, first, the image data Lab read by the image acquisition unit 10 is input to the image processing unit 26. The image data Lab processed by the image processing unit 26 is input to the intermediate switching unit 801b of the image processing unit 20, sent to the upstream switching unit 801a via the connection unit 801d, and then described with reference to FIG. Similarly, desired processing is performed in the pre-stage image processing unit 20a and the like.

  The second basic configuration shown in FIG. 4 includes a reading sensor module 18 and an IIT option board 24 that are different from the optical scanning system 16. On the IIT option substrate 24, for example, an image processing unit (B) 25 that digitally executes the same image processing as the signal processing unit 14 on the image acquired by the image acquisition unit 10, an optical scanning system 16, and reading An image processing unit (C) 26 that rotates an image read by the sensor module 18 and further enlarges or reduces as necessary, and an image (one page) read by the optical scanning system 16 or the reading sensor module 18 And a memory 27 (three in the figure, a, b, and c) that are temporarily held.

  A memory 27 indicated by a, b, and c in the drawing is provided for holding an image read by the reading sensor module 18.

  The memories 27a, 27b, and 27c are used as storage units that hold the images read by the reading sensor module 18 until the image processing unit 20 and the image output unit 30 start processing the images.

  The path route of image data when an image is formed on an image read by the reading sensor module 18 is as follows. That is, first, image data RGB read by the reading sensor module 18 is input to the image processing unit 25. In addition to the same processing as the signal processing unit 14, the image processing unit 25 performs pre-stage color conversion processing, and then the image processing unit 26 performs rotation and scaling processing as necessary. The image data Lab processed by the image processing unit 26 (only brightness data L in the case of a monochrome model) is temporarily held in the memory 27 and waits. At the start timing of the image forming process for the image, the image data Lab read from the memory 27 is input to the intermediate switching unit 801b of the image processing unit 20 and sent to the upstream switching unit 801a via the connection unit 801d. Thereafter, in the same manner as described with reference to FIG. 2, a desired process is performed in the pre-stage image processing unit 20a or the like.

  The third basic configuration shown in FIG. 5 is to input / output image data at the lower part of the intermediate switching unit 801b of the image processing unit 20 to bypass the image path, and to be external to the image processing unit 20. A desired process is performed. For example, the present invention can be used when processing for improving image quality (for example, density adjustment processing) is performed by performing desired image processing using image data of the entire page. In addition, a tandem gap correction function using a page memory for passing image data to the image output unit 30 sequentially at regular intervals so as to correspond to the tandem gap, document image allocation to one sheet, and processing page order When executing an image rearrangement function (so-called electronic sort; EPC (Electric Pre Collation)), the data storage device 1100 including the page data from the intermediate switching unit 801b (shown by a dotted line) And the processed image data Lab is received by the intermediate switching unit 801b. Alternatively, the data storage device 1100 may have the function of a sub image processing device, and the data storage device 1100 may perform desired image processing on image data in a device-independent Lab color space.

  In addition, in conjunction with an image rearrangement function such as page allocation or rearrangement (and tandem gap correction function), the attribute information (tag data tag) obtained by the image area separation processing and the image data are used as the image rearrangement function. It is preferable to reduce the dedicated TI memory by performing a synchronous output process in which the image and attribute information are read out and output in association with each other after being stored in common in the data storage device 1100 to be used. Further, when the image rearrangement function is performed (including the case where the image area separation processing function and the image rearrangement function are combined), the image is displayed on the image data in the device-independent color space (Lab in this example). It is preferable to execute a rearrangement function or to use image data in a device-independent color space for image area separation processing.

  Further, after the data storage device converts the data into YMCK color space, and performs desired image processing on the YMCK color space (may be similar to the image processing of the subsequent image processing unit 20b), the intermediate switching unit It is also possible to transfer the 8-bit image data captured in 801b and the intermediate switching unit 801b to the subsequent-stage switching unit 801c as it is via the connection unit 801d and pass it to the image output unit 30 side.

  In these cases, in order to reduce the memory capacity, the image data is compressed and stored in the page memory, and then the image compression memory function for decoding the read image data is used. The image data Lab corresponding to each of the output colors YMCK is sequentially fetched from the data storage device 1100, which is an example of the image storage processing device, to the intermediate switching unit 801b with a delay of a certain interval corresponding to the tandem gap. May be.

  Hereinafter, the description will be continued in the case where the data storage device 1100 for executing the image rearrangement function is connected to the intermediate switching unit 801b. As shown in FIG. 5, the data storage device 1100 stores an image compression / decompression processing unit (image compression / decompression processor), a sort processing unit (EPC) 1310 that performs a sorting processing function, and image data Lab, YMCK, and tag data tag. A page buffer (PB) 1312 serving as a page memory and a data storage unit 1314 including a hard disk drive (HDD), and a PCI interface unit (PCI I / F) 1322 serving as an interface unit. The data storage device 1100 as a whole has a buffer memory function.

  However, the target data at the time of sorting processing (whether the data interface to the data storage device 1100 is image data in a device-independent color space (Lab in this example) or the image output unit 30 side, that is, a device-dependent color space) The function differs greatly depending on whether the image data is the above (output color YMCK in this example), which will be described below with reference to Fig. 5. Which color space data is the target? The operation mode may be set according to, for example, an EPC mode setting input from the outside of the data storage device 1100. In addition, in the case of three types of data, it is a mode of image data in a device-independent color space, If the four systems of data are valid, the mode may be an image data mode in an output device-dependent color space. An identifier indicating the EPC mode may be added to the image data input from 0, and the identifier may be automatically recognized on the data storage device 1100. The identifier may be assigned to at least one color data. That's fine.

  For example, when the data storage device 1100 is used to execute the image rearrangement function on the image data in the device-independent color space (Lab in this example), the path route of the image data is as follows. . That is, first, the image data Lab read by the image acquisition unit 10 is input to the upstream image processing unit 20a via the upstream switching unit 801a, and the processed data is input to the data storage device 1100 via the intermediate switching unit 801b. The A configuration example of the data storage device 1100 in this case will be described with reference to FIG. The data storage device 1100 performs a sorting process, and corresponds to the image output unit 30 having a tandem structure, and has a delay (temporal difference) corresponding to the tandem gap to a page buffer 1312 and a data storage unit. From 1314, image data LabY, LabM, LabC, and LabK for each output color are read out in a time division manner.

  The output color image data LabY, LabM, LabC, and LabK are independently input to the color conversion unit 500 via the intermediate switching unit 801b with a temporal difference corresponding to the tandem gap. The color conversion unit 500 performs color conversion processing in synchronization with the operations of the corresponding image forming units 31Y, 31M, 31C, and 31K by a color conversion unit (see FIG. 2) provided according to each output color. By doing so, image data Y, M, C, and K for each output color are generated, and the image data Y, M, C, and K are transferred to the image processing unit 20c. The image data Y, M, C, and K processed by the image processing unit 20c are sent to the image output unit 30 via the post-switching unit 801c, and a visible image is formed on a predetermined output sheet by the image output unit 30. Is done.

  In such an image data path configuration, the page buffer 1312 and the data storage unit in the data storage device 1100 functioning as an input buffer memory at the operation timing of the image forming units 31Y, 31M, 31C, 31K corresponding to the output color YMCK, respectively. Data Lab is read from 1314 separately by time sharing (in time division). In other words, since the timing for reading out the data of each color is shifted by the tandem gap, the read data cannot be shared by each color, but the read processing from the page buffer 1312 or the like that functions as the input buffer memory is four times the normal processing. By performing time-sharing and speed-sharing separately at high speeds (that is, by reading in small pieces), both functions of absorbing output timing and resolving data contention in the tandem gap correction processing are performed from the page buffer 1312 or the like. This is realized by the reading process. Therefore, this configuration can be realized by a high-speed system, and cannot be realized by a low-speed system that cannot cope with quadruple speed reading. With regard to the tandem gap correction process, the read process from the input buffer can be realized in a system that includes a buffer memory that exhibits both a function of absorbing output timing and a function of eliminating data contention.

  Reading processing from the page buffer 1312 or the like is performed from another address such as the page buffer 1312 at the same time in a macro manner, but is performed by time sharing and not at the same time in a micro manner. Therefore, the image data LabY, LabM, LabC, and LabK corresponding to each color of YMCK are input to the color conversion unit 500 in a time division manner, and the corresponding color conversion unit 500 can use them exclusively. Therefore, the processing after the color conversion unit 500 does not need to be performed by time sharing, and the processing synchronized with the operation timing of the image forming units 31Y, 31M, 31C, and 31K corresponding to the output color YMCK may be performed individually. .

  On the other hand, the path route of the image data when executing the image rearrangement function on the image data (YMCK in this example) on the output device-dependent color space using the data storage device 1100 is as follows. . That is, first, the image data Lab read by the image acquisition unit 10 is input to the upstream image processing unit 20a via the upstream switching unit 801a, and the processed data is input to the color conversion unit 500 via the intermediate switching unit 801b. The The color conversion unit 500 is a color conversion unit (see FIG. 2) provided according to each output color at the same timing as the Y color as the first color (in synchronization with the operation of the image forming unit 31Y). ) Image data Y, M, C, and K for each output color are generated, and the image data Y, M, C, and K are transferred to the image processing unit 20c. Image data Y, M, C, and K processed by the image processing unit 20c are input to the subsequent switching unit 801c. The image data Y, M, C, and K are transferred from the post-stage switching unit 801c to the intermediate switching unit 801b via the connection unit 801d, and are independently input to the data storage device 1100 from here.

  A configuration example of the data storage device 1100 in this case will be described with reference to FIG. The data storage device 1100 performs a sorting process and synchronizes with the operations of the image forming units 31Y, 31M, 31C, and 31K having a tandem structure, and has a delay of a constant interval corresponding to the tandem gap, Image data Y, M, C, and K for each output color are read from the data storage unit 1314. Since the image data Y, M, C, and K corresponding to the output color YMCK are stored in advance independently in the page buffer 1312 or the like that functions as an input buffer memory, the conventional reading method may be used, and the conventional quadruple speed and time There is no need to share and read. In other words, the data conflict countermeasure in the tandem gap correction process is solved by storing the image data Y, M, C, and K corresponding to the output color YMCK in the page buffer 1312 functioning as an input buffer memory independently. ing. The countermeasure for absorbing the output timing in the tandem gap correction processing is eliminated by the reading processing from the page buffer 1312 or the like. The image data Y, M, C, and K read from the data storage device 1100 are independently input to the intermediate switching unit 801b with a temporal difference corresponding to the tandem gap, and switched to the subsequent stage via the connection unit 801d. To the image output unit 30 from here. Then, the image output unit 30 forms a visible image on a predetermined output sheet.

  In such an image data path configuration, data competition is resolved by storing it independently in the page buffer 1312 and the like, and absorption of output timing is resolved by reading it independently from the page buffer 1312. Quad-speed reading is not necessary and can be realized even with a normal low-speed system. With regard to the tandem gap correction process, the read process from the input buffer can be realized even in a system having a buffer memory that exhibits only the function of absorbing the output timing.

  FIG. 6 is a diagram showing a detailed example focusing on the function of the data storage device 1100 when the image rearrangement function is executed on image data (Lab in this example) in a device-independent color space. Here, not only the image data Lab but also tag data tag is shown.

  The data storage device 1100 includes a control unit 1122 that controls the entire data storage device 1100 and a small capacity that is an example of a semiconductor memory that holds image data Lab and tag data tag for one page (may be for several pages). A page buffer 1312 as a page memory unit (PM) and a data storage unit including a hard disk device (HDD) which is an example of a non-volatile mass storage medium capable of holding image data Lab and tag data tag for a large number of pages. And an image memory unit 1128 provided. The data storage device 1100 includes an image compression / decompression unit 1130 having an image compression / decompression processing function for compressing and decompressing image data.

  The data storage device 1100 includes an HDD controller that controls the hard disk device, and can electronically sort 8-bit multi-valued color images. Since the data storage device 1100 independently controls the data storage unit 1314 (that is, the hard disk device), the copy image can be controlled without degrading the performance of the printing operation (printer function). However, the system is expensive, such as controlling a hard disk device or providing a function for electronically sorting 8-bit multi-valued color images.

  The control unit 1122 and the image compression / decompression unit 1130 constitute a sort processing unit (EPC) 1310. The sort processing unit (EPC) 1310 and the image memory unit 1128 (that is, the page buffer 1312 and the data storage unit 1314) are electronic. A sort processing function unit and a tandem gap correction processing function unit are configured. The control unit 1122 according to the present embodiment includes a merge processing unit that outputs the image data Lab and the tag data tag in association with each other (merged) and outputs the merged data for each output color in the image forming unit 31Y, The function of the synchronous output process part which outputs according to the operation | movement by the side of 31M, 31C, 31K is provided.

  The image compression / decompression unit 1130 includes an image compression unit 1132 for encoding / compressing image data, and an image expansion unit 1134 for decoding / decompressing compressed image data. Although not shown, the image compression / decompression unit 1130 includes a parameter setting unit for setting compression / decoding parameters, a write control unit for controlling data writing to the page buffer 1312 and the like, and vice versa. A readout control unit for controlling the system is also provided.

  The image compression / decompression unit 1130 having the image compression / decompression processing function is used to perform electronic sorting using the image memory unit 1128 (page buffer 1312 and data storage unit 1314). At this time, the image compression / decompression unit 1130 compresses the image data in units of pages in a compressed image format such as JPEG or PNG (for example, a lossy format giving priority to the compression rate) and temporarily stores (compresses) the image data in the image memory unit 1128. Storage) or decompressing a compressed and stored print image (image data in units of pages).

  For example, the image compression unit 1132 includes image compression units 1132L, 1132a, and 1132b corresponding to the respective components of the input image data Lab. Similarly, the image expansion unit 1134 includes image expansion units 1134L, 1134a, and 1134b corresponding to the components of the input image data Lab. In the page buffer 1312 and the data storage unit 1314, image memory areas 1124L, 1124a, 1124b, 1126L, 1126a, 1126b for storing image data L, a, and b, respectively, and tag memory areas 1124T, 1126T for storing tag data are stored. And are secured respectively.

  The image compression units 1132a and 1132b increase the compression rate by sub-sampling the chromaticity data a and b. Sub-sampling reduces the resolution, but due to human visual characteristics, the sensitivity is high with respect to lightness, but the sensitivity with respect to color is low. In this way, there is no inconvenience, and high compression is achieved without causing image quality degradation. be able to.

  In addition, when priority is given to image quality, the lightness data L is irreversible compression capable of restoring the original image although the compression rate is low, while the chromaticity data a and b can be set to a high compression rate although the original image cannot be restored. If irreversible compression is used, for the above-described reason, the image quality can be reduced without causing deterioration of the image quality, and as a whole, high compression can be achieved.

  As indicated by the dotted lines in the figure, each component of the image data YMCK is output in a subsequent stage of the image decompression unit 1134 so as to output the decompressed image data Lab so as to correspond to each of the output colors YMCK. Have image processing units 1134Y, 1134M, 1134C, and 1134K. That is, each function unit of the data storage device 1100 has an individual processing function unit for each input component and output component.

  The image processing unit 1138 uses the tag data corresponding to the processing target image input from the image area separation processing unit 1000 side and held in the page buffer 1312 or the data storage unit 1314 to use the individual image elements in the image. It is good also as a thing of the structure which performs the adaptive process according to.

  Corresponding to the image output unit 30 having the tandem configuration, the data storage device 1100 has image data Lab and tag data from the page buffer 1312 and the data storage unit 1314 with a delay of a certain interval corresponding to the tandem gap. Read tag. For example, after starting the reading of the Y-color image data LabY as the first color, the M-color image data LabM is read out after a tandem gap Tym between the Y color and the M color as the second color. In addition, after starting the reading of the M-color image data LabM as the second color, the C-color image data LabC is read out after a tandem gap Tmc between the M color and the third color C. Finally, after the start of reading the C color image data LabC as the third color, the K color image data LabK is read out after a tandem gap Tck between the C color and the K color as the fourth color.

  As a result, the image data LabY, LabM, LabC, and LabK corresponding to each of the output colors YMCK are output from the data storage device 1100 with a delay of a constant interval corresponding to the tandem gap. The same applies to the tag data tag, and tag data TAGY, TAGM, TAGC, and TAGK corresponding to each of the output colors YMCK are output with a delay of a constant interval corresponding to the tandem gap. This function is called a tandem gap correction function.

  According to such a tandem gap correction function, the number of memories is reduced by reading out data for output colors (four systems of YMCK in this example) from one memory for each of the image data Lab and the tag data tag. can do. In other words, when outputting data with a delay of a certain interval corresponding to the tandem gap, a simple circuit configuration prepares memories for holding L, a, b and TAG according to each output color. However, in the above configuration, one L, a, b holding memory and TAG holding memory can be used. Of course, each memory for holding L, a, b and TAG may be a common memory.

  For example, the parameter setting unit determines a compression parameter for encoding compression in the image compression unit 1132. Next, the parameter setting unit inputs the determined encoding parameters for each image component to the corresponding image compression unit 1132 and image expansion unit 1134 for the image component. The image compression unit 1132 encodes and compresses the image data Lab captured using the set encoding parameters by a method such as orthogonal transform encoding such as DCT (Discrete Cosine Transform) or vector quantization. The encoded image data L, a, and b are generated by performing either reversible compression or reversible compression. Thereafter, the writing control unit stores the encoded image data of the components L, a, and b of the input image compressed by the image compression unit 1132 in a page buffer 1312 and a data storage unit 1314 that are examples of the image storage unit. Are simultaneously written in the corresponding storage areas.

  Next, in synchronization with a leading edge detection signal (a signal indicating a printing start point in the sub-scanning direction) from a leading edge detector (not shown) of the image output unit 30, the reading control unit reads each input image from the page buffer 1312 and the data storage unit 1314. The encoded image data of the components L, a, and b are sequentially read out at regular intervals (YMCK delay) so as to absorb the tandem gap, and input to the image expansion unit 1134. As shown in FIG. 6B, there is a timing at which a plurality of output colors are processed in parallel. In this case, image data and tag data are read out from the image memory unit 1128 by time division, and the image data Lab is read out. Are transferred to the image compression / decompression unit 1130, and the tag data tag is transferred to the tag compression / decompression unit 1142.

The image decompression unit 1134 sequentially outputs the encoded image data of the input components L, a, and b for the output colors Y, M, C, and K that are sequentially read from the page buffer 1312 and the data storage unit 1314 at regular intervals. Using the encoding parameters set by the parameter setting unit, decoding (decompression processing) corresponding to the encoding in the image compression unit 1132 is performed to return to the original image data (decoded data), and each output color Y, The decoded data L, a, and b for M, C, and K are set (set) and input to corresponding ones in the image processing unit 1138. The tag data tag is also subjected to the same expansion processing by the tag compression / expansion unit 1142. More specifically, “set (set) and input to corresponding one” means “set decoded data L, a, and b for output color Y to set (set)” as shown in FIG. Are input to the output color Y image processing unit 1138 (Y system in FIG. 6) ”and“ decoded data L, a, b for the output color M are set (set), Input to the image processing unit 1138 (M system in FIG. 6) ”,“ decoded data L, a, b for output color C are set (set), and image processing unit 1138 for output color C (FIG. 6) ”And“ decoded data L, a, b for output color K are set (set) and input to image processing unit 1138 for output color K (K system in FIG. 6) ”. ".

  In the image processing unit 1138, for example, desired image processing is performed on the decoded data Lab for the output colors Y, M, C, and K. The processed image data LabY, LabM, LabC, and LabK are merged with the tag data tag and passed to the image processing unit 20.

  When the control unit 1122 merges and outputs the image data Lab and the tag data tag, the control unit 1122 performs an original image allocation to one sheet of paper, a processing page order rearrangement function (electronic sort function), and a tandem gap correction function. Execute. That is, regardless of the order in which the image data Lab and the tag data tag are stored in the image memory unit 1128, the image data Lab and the tag data tag of the page necessary for realizing these functions are associated with each other and a tandem gap correction function is performed. Thus, the synchronous output process is executed by reading out.

  For the electronic sort function and the tandem gap correction function, for example, as shown in the lower right in FIG. 6A, image data Lab and tag data tag of a necessary page are read out from the data storage unit 1314 in association with each other. Temporarily stored in the page buffer 1312. Then, in order to absorb the output timing corresponding to the tandem gap and to eliminate the data competition, time sharing is performed at the operation timing of the image forming units 31Y, 31M, 31C, and 31K corresponding to the output color YMCK (in a time division manner), and the page Data Lab is read from the buffer 1312. In such an operation configuration, the data storage unit 1314 functions as a main storage unit for the electronic sort function, and the page buffer 1312 functions as a main storage unit of the tandem gap correction function.

  In such a configuration, the electronic sort, the tandem gap correction function, and the like are executed on the image data in the device-independent Lab color space, not in the output device-dependent YMCK color space, and the number of colors to be processed is the image. Since there are fewer output colors than the output color on the output unit 30 (engine / output device) side, control is simpler than the configuration for performing electronic sorting and tandem gap correction on a general YMCK color space (particularly memory and The control function unit for writing and reading can be made compact.

  In addition, data sorted in a device-independent color space can be transmitted to an external device via a network, which is convenient. At this time, the brightness data L is irreversibly compressed (or reversible compression), and the chromaticity data a and b are subsampled and then irreversibly compressed (or reversible compression), so that the transfer data capacity is data in the YMCK color space. Since it can be reduced rather than transferring as. Furthermore, tag data (lossy compression or lossless compression) can also be transmitted in pairs with image data in a device-independent color space, which is more convenient.

  If the number of pages subject to electronic sort processing is small, only the page buffer 1312 can function as a storage unit for both functions. In addition, if the data storage unit 1314 has a high-speed enough to follow the reading process having a tandem gap correction function, a storage area for tandem gap correction is prepared in the data storage unit 1314, and the sorted image is stored there. It is also possible to execute the reading process so as to perform a tandem gap correction function. In this case, only the data storage unit 1314 can function as a storage unit for both functions. That is, in any case, the storage unit of the electronic sort processing function unit is also used as the storage unit of the tandem gap correction processing function unit.

  FIG. 7 is a diagram illustrating a detailed example focusing on the function of the data storage device 1100 when the image rearrangement function is executed on the image data (YMCK in this example) on the output device-dependent color space. Here, not only the image data YMCK but also the tag data tag is shown. Here, only differences from the configuration of the image data Lab in the device-independent color space shown in FIG. 6 will be described.

  The image compression unit 1132 includes image compression units 1132Y, 1132M, 1132C, and 1132K corresponding to the respective components of the input image data YMCK. Similarly, the image expansion unit 1134 includes image expansion units 1134Y, 1134M, 1134C, and 1134K corresponding to the respective components of the input image data YMCK. Image memory areas 1124Y, 1124M, 1124C, 1124K, 1126Y, 1126M, 1126C, and 1126K for storing image data Y, M, C, and K, respectively, are secured in the page buffer 1312 and the data storage unit 1314, respectively. As shown by the dotted line in the figure, image processing units 1134Y, 1134M, 1134C, and 1134K corresponding to the respective components of the decompressed image data Y, M, C, and K are provided at the subsequent stage of the image decompressing unit 1134. . That is, each function unit of the data storage device 1100 has an individual processing function unit for each output color component.

  The same applies to the tag data tag, and although not shown, a tag compression / decompression unit 1142 and an image memory area 1128T for tag data are provided for each output color component. For example, memory areas 1128TAGY, 1128TAGM, 1128TAGC, and 1128TAGK for respectively storing tag data TAGY, TAGM, TAGC, and TAGK for each output color are secured in the image memory 1128T (page buffer 1312 and data storage unit 1314). .

  When the control unit 1122 merges and outputs the image data YMCK and the corresponding tag data tag, it assigns the original image to one sheet, rearranges the processing page order (electronic sort function), and tandem gap correction function. And execute. That is, regardless of the order in which the image data YMCK and the corresponding tag data tag are stored in the image memory unit 1128, the image data YMCK and the tag data tag of the page necessary for realizing these functions are associated with each other and the tandem gap correction function is performed. The synchronous output process is executed by reading so as to fulfill the above.

  The processing for the electronic sort function is the same as in FIG. 6, and as shown in the lower right in FIG. 7A, the necessary page image data YMCK and the corresponding tag data tag (for example, Y) TAGY) are associated with each other and read from the data storage unit 1314 and temporarily stored in the individual image memory areas 1124Y, 1124M, 1124C, and 1124K provided in the page buffer 1312. As a result, a countermeasure for resolving data conflict in the tandem gap correction function is realized.

  On the other hand, when the absorption of the output timing for the tandem gap in the tandem gap correction function is realized, the corresponding image of the page buffer 1312 is operated at the operation timing of the image forming units 31Y, 31M, 31C, and 31K according to the output color YMCK. Data Y, M, C, and K are read independently from the memory areas 1124Y, 1124M, 1124C, and 1124K.

  As shown in FIG. 7, an image compression unit 1132, an image expansion unit 1134, and a tag compression / expansion unit 1142 for image data (YMCK in this example) in an output device-dependent color space are provided as a data storage device 1100. By doing so, sorting processing and tandem gap correction processing can be realized not only for image data in the output device-dependent color space but also for image data in a device-independent color space. It is. Data depending on whether the processing target data is image data in the device-independent color space (Lab in this example) or image data in the output device-dependent color space (in this example, output color YMCK) As described above, the setting of the operation mode of the storage device 1100 may be performed according to EPC mode setting input from the outside or switching by automatic recognition.

<Example of system configuration for copying machines>
FIGS. 8 to 12 are diagrams for explaining an example of development of the system configuration in the case where the image processing unit 20 shown in FIG. 2 is combined with various connection devices to constitute the copying apparatus 1 having the function of a multifunction peripheral. It is. It is assumed that the image processing unit 20 used in each figure is configured by an ASIC that can be connected to a PCI bus.

  8 to 12, the signal processing unit 14 as the pre-image processing unit (A) 21 is shown outside the image acquisition unit 10. In the copying apparatus 1, the post image processing unit (B) 22 that generates output image data used on the image output unit 30 side based on the image data read by the image acquisition unit 10 is mainly used for the image acquisition unit 10. It is configured to be incorporated in an IIT (Image Input Terminal) module. As the image processing unit 22, the image processing unit 20 shown in FIG. 2 is used.

  The first example shown in FIG. 8 is a typical configuration example, and full color (FC) printing using four colors of YMCK based on binarized data and monochrome (B) using only K colors. / W; Black and White) A configuration for printing. It is also possible to perform single color printing with any one of YMC. It is also possible to perform two-color printing with any two colors of YMC (which may further include K).

  The image output unit 30 includes a printer system that prints out based on image data captured from the outside. The image output unit 30 includes a bridge 1220 that switches between a copying system and a printer system, a screen processing unit 1222 that screen-processes the color image data YMCK (or monochrome image data LL) selected by the bridge 1220, and a screen. A laser driver 1224 for driving the semiconductor laser 38 (see FIG. 1) based on the image data screen-processed by the processing unit 1222 is provided.

  The printer system of the image output unit 30 includes a drawing development processing unit (BB) 1230 that renders (rasterizes) image data acquired from an external image input terminal based on image data for print processing, and this drawing development processing unit. MPU 1232, ROM 1234, and RAM 1236 for controlling 1230 and other functional units, and an interface unit 1240 for receiving image data (for example, in PDL format) from a personal computer or the like via a wired / wireless LAN, and storing the received data A data storage unit 1242 including a hard disk device (spooling) or the like is included. The interface unit 1240 can perform an electronic sorting function and a tandem gap correction function in cooperation with the data storage unit 1242.

  The interface unit 1240 can also receive image data via a general-purpose I / F such as USB or IEEE1394. For example, the image output unit 30 includes a FAX data processing unit 1244 that transmits and receives FAX data from the communication system. The FAX data processing unit 1244 sends the received FAX data to the interface unit 1240.

  The interface of data (image data and control data) between the functional units in the image output unit 30 uses a PCI bus generally used in a personal computer or the like. For example, the first PCI bus interface (PCI 1st) is used between the drawing development processing unit 1230, the bridge 1220, and the interface unit 1240, and the second PCI is used between the drawing development processing unit 1230 and the MPUs 1232, 1334, and the RAM 1236. Each is connected by a bus interface (PCI 2nd).

  The drawing development processing unit 1230 performs drawing processing, performs the same processing as that of the previous image processing unit 20a of the image processing unit 20, and then passes the output data for printing to the image output unit 30 side via the bridge 1220. Further, the image data YMCK drawn and developed by the drawing development processing unit 1230 is supplied to the subsequent image processing unit 20b via the intermediate switching unit 801b of the image processing unit 20, for example, so that the previous image processing of the image processing unit 20 is performed. It can also be set as the structure processed using the part 20a.

  The configuration of the image output unit 30 of the first example shown in FIG. 6 includes an electronic sort unit () 1210 having an electronic sort function and a tandem gap correction function. The electronic sort unit 1210 is connected to a page buffer (PB) 1212 serving as a page memory for storing image data YMCK taken from the image processing unit 22 almost simultaneously when a color image is output. The electronic sort unit 1210 receives the color image data YMCK output from the image processing unit 22 at the same time for the electronic sort function with a small amount of data such as binary or quaternary image formation data, and receives a tandem gap. It is provided to realize a tandem gap correction function that outputs with a time difference corresponding to each of the output colors YMCK with a delay of a constant interval corresponding to minutes.

  If the number of YMCK colors is about 50, an electronic sort function can be realized by using the page buffer 1212 connected to the electronic sort unit 1210. When the storage number exceeds the storage capacity of the page buffer 1212 (that is, the electronic sort unit 1210), the data storage unit 1242 is connected to the interface unit 1240 via the bridge 1220 provided on the right side of the electronic sort unit 1210 in the drawing. It is also possible to operate so as to fulfill the electronic sort function. In other words, when viewed from the image processing unit 20 side, only the electronic sort unit 1210 can perform the electronic sort function, and the electronic sort unit 1210, the interface unit 1240, and the data storage unit 1242 can also perform the electronic sort function. In any case, in the configuration of the first example in which the electronic sort unit 1210 is inserted, only the electronic sort function for the output device-dependent color space data YMCK can be realized.

  Instead of the electronic sort unit 1210, the data storage device 1100 described above can be used. However, the data storage device 1100 includes an HDD controller that controls the hard disk device, and can electronically sort 8-bit multi-valued color images, and controls copy images without degrading the performance of printing operations. However, the 8-bit multi-value color image function is excessive for a system targeting binary full color (FC). Therefore, it is preferable to use the electronic sort unit 1210 in an inexpensive system that targets binary full color (FC), and the data storage device 1100 in a system that prioritizes performance or multi-valued color images.

  The image data path route during the copying operation in the configuration of the first example is as follows. That is, the image data RGB read by the image acquisition unit 10 is subjected to predetermined processing by the image processing unit 21 (that is, the signal processing unit 14) and then subjected to previous color conversion, and the image data Lab is converted to the image processing unit 22 (that is, the image processing unit 22). It is input to the upstream switching unit 801a of the image processing unit 20). In the image processing unit 20, predetermined processing is performed through the preceding image processing unit 20a → the intermediate switching unit 801b → the subsequent image processing unit 20b, and the image forming data Y, M, C, and K are independent from the subsequent switching unit 801c. Are input to the electronic sort unit 1210.

  In the electronic sort unit 1210, sorting processing such as image allocation and rearrangement of the processing page order is performed, and image data is sequentially spaced at regular intervals so as to correspond to the tandem gap according to the image forming unit 31 configured in tandem. Y, M, C, and K are output to the bridge 1220. Then, the screen processing unit 1222 performs screen processing for each output color, and an image of each output color is sequentially formed by driving the laser driver 1224 based on the image formation data Y, M, C, K of each output color. The

  The second example shown in FIG. 9 is a monochrome (B) that performs full color (FC) printing using four colors of YMCK based on multi-value data and uses only K color based on binary data. / W; Black and White) A configuration for printing. In the post image processing, the image path is bypassed to the electronic sort function, and the sorting process and the tandem gap correction function are executed in the electronic sort function.

  The difference from the configuration of the first example shown in FIG. 8 is that an image processing unit (C) 26 having a rotation function for rotating the image read by the image acquisition unit 10 by 90 degrees (270 degrees) in the IIT module is firstly provided. The IIT option board 24 is included, and the accelerator 1300 is provided between the image processing unit 22 and the image output unit 30.

  The accelerator 1300 includes an image processing unit (D) 28, a sort processing unit (EPC) 1310 that performs an electronic sort function, a page buffer 1312, a data storage unit 1314, and a PCI interface unit (PCI I / F) 1322. A data storage device 1100 and a PCI interface unit (PCI I / F) 1320 are provided. Since the sort processing unit 1310 corrects the tandem gap, the electronic sort unit 1210 and the page buffer 1212 in the image output unit 30 are removed. As the image processing unit 28 in the accelerator 1300, the image processing unit 20 shown in FIG. 2 is used.

  That is, by using the image processing unit 20 shown in FIG. 2 as a two-stage configuration as the image processing unit 22 in the IIT module and the image processing unit 28 in the accelerator 1300 (use of two), a post image processing unit is used. To make up. When four-color full-color printing is performed based on multi-valued data, the processing becomes complicated. Therefore, the post image processing unit is configured in two stages to share processing and take measures.

  For example, in the image processing unit 20 shown in FIG. 2, the image processing unit 22 is mainly responsible for the function of the preceding image processing unit 20a, and the image processing unit 26 is mainly responsible for the function of the subsequent image processing unit 20b. And The image processing units 22 and 28 use the first path switching unit 801 to pass the unused one of the preceding image processing units 20a and 20b, respectively.

  In the image data path route during the copying operation in the configuration of the second example, the path route of the image processing unit 22 and the image processing unit 26 in the IIT option board 24 is as shown in FIG. However, the processed image data Lab processed by the preceding image processing unit 20a is input to the intermediate switching unit 801b, and then passed through the subsequent image processing unit 20b (filtering is performed if necessary). Alternatively, the image data Lab is transferred to the subsequent-stage switching unit 801c through the connection unit 801d.

  The path route in the image processing unit 28 and the data storage device 1100 arranged on the subsequent stage side is as shown in FIG. For example, when the image processing unit 28 receives the image data Lab or the tag data tag from the preceding image processing unit 22 at the preceding switching unit 801a of the first path switching unit 801, the image processing unit 28 causes the preceding image processing unit 20a to pass through. The image data Lab is transferred to the intermediate switching unit 801b via the connection unit 801d (filtering or the like is performed if necessary).

  Thereafter, when the image rearrangement function is executed on the image data Lab in the device-independent color space, the image data Lab is transferred from the intermediate switching unit 801b to the data storage device 1100, and the image allocation or processing page order is performed. After sorting processing such as rearrangement is performed, image data LabY, LabM, LabC, and LabK for each output color are input to the intermediate switching unit 801b with a delay of a constant interval so as to correspond to the tandem gap. The Then, color conversion processing is performed in synchronization with the operations of the corresponding image forming units 31Y, 31M, 31C, and 31K in each processing function unit (see FIG. 2) provided in accordance with each output color of the post-stage image processing unit 20b. Or desired image processing is performed, and processed image data Y, M, C, and K are output to the bridge 1220 via the post-stage switching unit 801c. Then, the screen processing unit 1222 performs screen processing for each output color, and an image of each output color is sequentially formed by driving the laser driver 1224 based on the image formation data Y, M, C, K of each output color. The

  On the other hand, when the image rearrangement function is executed with the image data YMCK in the output device-dependent color space, the processed data Lab in the preceding image processing unit 20a is transferred to the subsequent image processing unit 20b via the intermediate switching unit 801b. And the operation of the image forming unit 31Y for the first color (Y color in this example) at each processing function unit (see FIG. 2) provided according to each output color of the post-stage image processing unit 20b. Color conversion processing and desired image processing are performed in synchronization, and processed image data Y, M, C, and K are input to the subsequent-stage switching unit 801c. The image data Y, M, C, and K are transferred to the data storage device 1100 via the connection unit 801d and the intermediate switching unit 801b. The data storage device 1100 performs a sorting process, and passes image data Y, M, C, and K for each output color to the intermediate switching unit 801b with a delay of a predetermined interval corresponding to the tandem gap. Perform the correction function. The image data Y, M, C, and K input to the intermediate switching unit 801b are output to the bridge 1220 via the connection unit 801d and the subsequent switching unit 801c. Then, the screen processing unit 1222 performs screen processing for each output color, and an image of each output color is sequentially formed by driving the laser driver 1224 based on the image formation data Y, M, C, K of each output color. The

  The third example shown in FIG. 10 is configured to perform monochrome printing using only K colors based on multi-value data. The IIT module has the same configuration as that of the second example illustrated in FIG. 9, but includes a data storage device 1100 between the IIT module and the image output unit 30 instead of the electronic sort unit 1210 in the first example. An accelerator 1300 is provided. The electronic sort unit 1210 has only an electronic sort function for data with a small amount of data such as binary or quaternary image formation data, and realizes an electronic sort function for multilevel data without causing performance degradation. It is to do. The image processing unit 22 is configured to input output device-dependent image data YMCK to the data storage device 1100. The data storage device 1100 has an image rearrangement function using the image data YMCK in the output device-dependent color space. Execute.

  In the image data path route during the copying operation in the configuration of the third example, the path route of the image processing unit 22 and the image processing unit 26 in the IIT option board 24 is as shown in FIG. Note that the output data processing unit 700 of the image processing unit 22 executes a 4-bit error diffusion processing function that operates as dither. The image data YMCK output from the image processing unit 22 is input to the data storage device 1100 and subjected to sorting processing. At this time, the data storage device 1100 stores the image data in the data storage unit 1314 or the like by lossless compression. The data storage device 1100 executes the tandem gap correction function by outputting the image data Y, M, C, and K for each output color to the bridge 1220 with a delay of a predetermined interval corresponding to the tandem gap. Thereafter, screen processing is performed for each output color by the screen processing unit 1222, and an image of each output color is sequentially formed by driving the laser driver 1224 based on the image formation data Y, M, C, K of each output color. Is done.

  The fourth example shown in FIG. 11 is a configuration in which the IIT option board 24 shown in FIG. 4 is provided in the IIT module based on the configuration of the first example shown in FIG. In the image data path route during the copying operation in the configuration of the fourth example, the path route of each functional unit in the image processing unit 22 and the IIT option board 24 is as shown in FIG. The output device-dependent image data YMCK is input from the image processing unit 22 to the electronic sort unit 1210. The electronic sort unit 1210 uses the image data YMCK in the output device-dependent color space to perform an image rearrangement function or tandem. Perform gap correction function.

  The fifth example shown in FIG. 12 is a configuration in which the IIT option board 24 shown in FIG. 4 is provided in the IIT module based on the configuration of the second example shown in FIG. Among the configuration examples, it has the highest functionality and the best printing operation performance. In the image data path route during the copying operation in the configuration of the fifth example, the path route of each function unit in the front stage side (image processing unit 22) and the IIT option board 24 having a two-stage configuration is as follows. This is as shown in FIG. Further, the post-stage side of the post image processing unit (image processing unit 28) and the path route of the data storage device 1100 having the two-stage configuration are as shown in FIG. As shown in the configuration of the second example, the image processing unit 28 on the rear stage side selectively selects either device-independent image data Lab or output device-dependent image data YMCK in the intermediate switching unit 801b. The data can be input to the data storage device 1100. Therefore, in this fifth example, the data storage device 1100 uses the image rearrangement function and the tandem gap correction for both the image data Lab in the device-independent color space and the image data YMCK in the output device-dependent color space. It is possible to perform the function.

  As described above, according to the configuration of the image processing unit 20 of the above-described embodiment, the first path switching unit 801 capable of switching the input / output of the image processing path is provided, and further, the input / output unit (previous stage in the above example) is provided. As a data interface in the switching unit 801a, the intermediate switching unit 801b, and the subsequent switching unit 801c), image data on a device-independent color space (Lab data in the above example) and image data on an output device-dependent color space (above In the example, any of YMCK data) can be selectively input / output supported. As a result, for example, the data storage device 1100 uses two types of color space data by adopting an intermediate switching unit 801b as an input / output interface with a function unit (in the above example, the data storage device 1100) that performs electronic sorting and a tandem gap correction function. It is now possible to construct systems with various speeds and configurations using the same type of image processing unit (for example, an image processing unit configured with an ASIC).

  For example, when constructing a high-speed system that needs to perform the read control of the buffer memory at a speed that is several times the number of output colors, a path route with device-independent data as input / output targets as in the Lab color space, When constructing a low-speed system that performs read control at a normal speed without performing read control at a speed that is several times the number of output colors, a path route that uses output device-dependent data as an input / output target as in the YMCK color space is used. The same image processing unit can be used for both high-speed and low-speed systems by the image path switching function of the first path switching unit 801. That is, redundancy can be suppressed even when the system is compatible with various speeds and performances. In addition to various correspondences regarding the electronic sort and the tandem gap correction function, an image forming apparatus having various functions and performances can be constructed for the configuration on the image acquisition unit 10 side.

  In addition, by configuring such an image processing unit with a semiconductor integrated circuit such as an ASIC, the same substrate on which the image processing unit configured with the ASIC is mounted can be used for various systems. . In addition, since the same substrate can be used for various models, manufacturing is also facilitated. In addition, combined with the mass production effect of the ASIC, the device cost can be reduced.

  In addition, by adopting the input / output interface of the image processing unit 20 at the upstream switching unit 801a and the downstream switching unit 801c, it is possible to construct a system in which a plurality of image processing units 20 are connected in cascade or in parallel. This makes it possible to construct systems with various functions and configurations, such as sharing the processing burden.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Various changes or improvements can be added to the above-described embodiment without departing from the gist of the invention, and embodiments to which such changes or improvements are added are also included in the technical scope of the present invention.

  Further, the above embodiments do not limit the invention according to the claims (claims), and all combinations of features described in the embodiments are not necessarily essential to the solution means of the invention. Absent. The embodiments described above include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. Even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, as long as an effect is obtained, a configuration from which these some constituent requirements are deleted can be extracted as an invention.

  For example, in the above-described embodiment, the handling on the YMCK color space as an example of the output device-dependent color space and the Lab color space as an example of the device-independent color space has been described. It is not limited. For example, the present invention can be similarly applied to a device-independent color space such as Luv as another coordinate system. In addition, the input device is not limited to device-independent data, and is, for example, handling between input device-dependent image data such as RGB color space and output device-dependent image data (for example, YMCK data). May be.

  In the above-described embodiment, the copying apparatus has been described as an example. However, in any image forming apparatus that can output a color image to a predetermined output medium such as a printing apparatus (printer) or a facsimile apparatus, an image forming unit (engine) is provided. Applicable to all tandem configurations.

1 is a mechanism diagram of an example of a copying apparatus equipped with an embodiment of an image processing apparatus according to the present invention. FIG. 3 is a circuit block diagram of an embodiment of an image processing unit provided in the copying apparatus having the above configuration. It is a figure explaining the 1st basic composition of the cooperation method of the image processing part shown in FIG. 2, and another connection device. It is a figure explaining the 2nd basic composition of the cooperation method of the image processing part shown in Drawing 2, and other connected devices. It is a figure explaining the 3rd basic composition of the cooperation method of the image processing part and other connection devices shown in FIG. It is a figure which shows the detailed example which paid its attention to the function of the data storage device in the case of performing an image rearrangement function with the image data on a device-independent color space. It is a figure which shows the detailed example which paid its attention to the function of the data storage device in the case of performing an image rearrangement function with the image data on output device dependent color space. FIG. 6 is a diagram illustrating a first example of a copying apparatus in which the image processing unit illustrated in FIG. 2 and the connection device illustrated in FIGS. 3 to 5 are combined. FIG. 6 is a diagram illustrating a second example of a copying apparatus in which the image processing unit illustrated in FIG. 2 and the connection device illustrated in FIGS. 3 to 5 are combined. FIG. 6 is a diagram illustrating a third example of a copying apparatus in which the image processing unit illustrated in FIG. 2 and the connection device illustrated in FIGS. 3 to 5 are combined. FIG. 6 is a diagram illustrating a fourth example of a copying apparatus in which the image processing unit illustrated in FIG. 2 and the connection device illustrated in FIGS. 3 to 5 are combined. FIG. 6 is a diagram illustrating a fifth example of a copying apparatus in which the image processing unit illustrated in FIG. 2 and the connection device illustrated in FIGS. 3 to 5 are combined.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Copying apparatus, 10 ... Image acquisition part, 11 ... Platen glass, 12 ... Light source, 13 ... Light-receiving part, 14 ... Signal processing part, 20 ... Image processing part, 20a ... Pre-stage image processing part, 20b ... Later-stage image processing part , 20c ... peripheral part, 30 ... image output part, 31 ... image forming part, 32 ... photosensitive drum, 106 ... preceding filter processing part, 110 ... background detection processing apparatus, 200 ... magnification processing part, 300 ... post-filtering process , 500 ... Color conversion unit, 600 ... Subsequent color adjustment unit, 700 ... Output data processing unit, 801 ... First path switching unit, 1100 ... Data storage device, 1122 ... Control unit, 1128 ... Image memory unit, 1132 ... Image Compression unit, 1134... Image expansion unit, 1138... Image processing unit, 1142.

Claims (11)

In an image processing apparatus used in a tandem image forming apparatus in which image forming units are arranged in cascade for the number of output colors,
A pre-stage image processing unit that performs image processing on output device independent data that is image data on a color space independent of the image forming unit;
A color conversion unit that converts processed output device-independent data processed by the preceding image processing unit into output device-dependent data that is image data on a color space dependent on the image forming unit;
A subsequent image processing unit that performs image processing on output device-dependent data obtained by the color conversion unit;
An interface unit that selectively inputs and outputs the output device-dependent data and the output device-independent data;
The interface unit has data bidirectionality, and has a pipeline processing function for switching input / output data of an image processing path. The interface unit receives data input from any of the image processing blocks via the interface unit. A path switching unit that performs a switching process to be output data to the corresponding subsequent block via
With
The path switching unit outputs the output device-independent data from the interface unit, and captures the output device-independent data from the interface unit with a temporal difference corresponding to a tandem gap to a corresponding functional unit. Pass image processing device. The color conversion unit has independent color conversion function units corresponding to the number of the output colors,
The path switching unit outputs the output device-independent data from the interface unit, and converts the independent output device-independent data corresponding to the number of output colors with a time difference corresponding to a tandem gap. The image processing apparatus according to claim 1, wherein a path route is controlled so as to capture from the interface unit and pass output device-independent data for each output color to the corresponding color conversion function unit. The path switching unit outputs the output device-dependent data independent of the output color from the interface unit, and outputs the independent output device-dependent data corresponding to the number of the output colors over a tandem gap. The image processing apparatus according to claim 1, wherein the path route is controlled so as to be fetched from the interface unit with a difference and to pass the output device-dependent data for each output color to each function unit in the image processing apparatus or to the outside. The interface unit outputs processed output device-independent data processed by the preceding image processing unit, takes in output device-independent data that has been subjected to predetermined processing externally, and passes the output device-independent data to the color conversion unit The image processing apparatus according to any one of claims 1 to 3. The interface unit outputs the processed output device-dependent data processed by the subsequent image processing unit, and takes in the output device-dependent data processed externally. The image processing apparatus according to item. An image forming apparatus that forms a visible image on a predetermined output medium based on input image data,
An image forming unit that forms a visible image on an output medium based on image data, and the image forming unit is a tandem type arranged in cascade for the number of output colors,
A pre-stage image processing unit that performs image processing on output device independent data that is image data on a color space independent of the image forming unit;
A color conversion unit that converts the processed output device-independent data processed by the preceding image processing unit into output device-dependent data that is image data on a color space dependent on the image forming unit;
A subsequent image processing unit that performs image processing on output device-dependent data obtained by the color conversion unit;
An interface unit that selectively inputs and outputs the output device-independent data and the output device-dependent data;
The interface unit has data bidirectionality, and has a pipeline processing function for switching input / output data of an image processing path. The interface unit receives data input from any of the image processing blocks via the interface unit. A path switching unit that performs a switching process to be output data to the corresponding subsequent block via
With
The path switching unit outputs the output device-independent data from the interface unit, and captures the output device-independent data from the interface unit with a temporal difference corresponding to a tandem gap to a corresponding functional unit. Pass Image forming device. The data storage unit that performs tandem gap correction processing using the output device-independent data or the output device-dependent data input through the interface unit as processing target data is connected to the interface unit. Image forming apparatus. The image forming apparatus according to claim 7, wherein the data storage unit performs electronic sort processing using image data in the same color space as data used for the tandem gap correction processing as processing target data. The image forming apparatus according to claim 7 or 8, wherein the data storage unit selects any one of the output device-independent data and the output device-dependent data as the processing target data. The data storage unit takes in the output device-independent data via the interface unit of the image processing unit, and the independent output device-independent data corresponding to the number of output colors is a time corresponding to a tandem gap. The image forming apparatus according to claim 7, wherein the image forming apparatus inputs data to the interface unit with a difference. The data storage unit takes in the output device dependent data independently for the output color via the interface unit of the image processing unit, and tandems the independent output device dependent data for the number of the output colors. The image forming apparatus according to claim 7, wherein the image forming apparatus inputs to the interface unit with a time difference corresponding to a gap.

Images