JP2011081278A - Image forming apparatus and system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that it is made impossible to execute printing with special toner because information about drawing patterns of the special toner is erased when each bit of attribute information is masked. <P>SOLUTION: A compression ratio of the attribute information can be increased while holding information of the special toner by down-sampling processing of information of the special toner, and the ratio for executing printing with basic four colors and the special toner is increased. Also, when the information of the special toner is erased, the printing with the special toner is reliably executed by shifting to two-step printing. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image processing method for automatically performing many complicated settings that occur in order to realize selection of a visual effect when printing output using transparent toner.

  In recent years, digital printing technology has been steadily increasing its utility value in the on-demand printing market and the small number of document printing market. In particular, full-color printing using electrophotographic technology has an advantage over other printing technologies in terms of productivity, printing cost, and ease of maintenance, and is rapidly expanding its market. Among them, in particular, not only full-color printing by conventional CMYBK and electrophotographic printing using basic four-color toners, but also multicolor printing methods using special toners are attracting attention, The immediate special printing market is also in the horizon. Examples of the special toner include a transparent toner that absorbs unevenness on the surface of the printed material and realizes high gloss, and a light toner that can suppress roughness of the highlight portion. By using special toner, new added value different from normal digital printing can be obtained, and the world of digital printing can be further expanded. In view of the above background, color multifunction peripherals (hereinafter referred to as MFPs) on which special toner is mounted have been put on the market.

  In the MFP, image data and attribute information corresponding to each pixel of the image data are held in a memory, image processing corresponding to the attribute information is performed on the image data, and printing is performed. In order to mount the special toner in the MFP, the print data of the special toner is developed into a binary drawing pattern and combined with the attribute information. Image processing such as color conversion and screen processing is performed on the image data in accordance with the attribute information, and a CMYBk basic four-color toner drawing pattern is generated. The special toner drawing pattern synthesized from the attribute information is taken out, the basic four-color drawing pattern and the special toner drawing pattern are sent to the print engine, and printing is performed.

  Each memory for holding image data and attribute information is provided with a predetermined memory limit. Therefore, the image data is compressed by irreversible compression so that the capacity is equal to or less than a predetermined memory amount. On the other hand, attribute information is compressed by lossless compression in order to prevent bit loss, and thus may exceed a predetermined amount of memory. As a process for exceeding the limit, Patent Document 1 proposes a means for storing each bit of the attribute information by masking (replacement with a specific value) and increasing the compression rate so that the amount of memory is less than a predetermined amount of memory. .

JP 2006-086649 A

  However, since the drawing pattern of the special toner is combined with the attribute information and stored, if each bit of the attribute information is masked, the information on the drawing pattern of the special toner is erased and the special toner cannot be printed. is there.

  In order to hold the information of the special toner, a means for increasing the compression rate by down-sampling the drawing pattern of the special toner can be considered. However, if downsampling is performed uniformly, if special toner is used for image modification (glossy, etc.), the special toner drawing pattern and image will be misaligned, the effect of modification will be reduced, and the image will deteriorate. The problem that it ends up occurs.

  The modification of the image with the transparent toner, which is one of the special toners, can obtain a glossy image print result (FIG. 34) by overwriting the image data (FIG. 32) with the transparent toner data (FIG. 33). it can.

  In the case of the downsampled transparent toner data (FIG. 35), a deviation from the image data (FIG. 32) occurs, and the image of the print result (FIG. 36) deteriorates.

  In order to solve the above problems, an image forming apparatus according to the present invention is an image forming apparatus capable of printing using special color toners in addition to the basic four colors of cyan, magenta, yellow, and black. Means for storing attribute information for each pixel of the image data, storing the image data in a memory, combining means for combining spot color information with each pixel of the attribute information, and compressing the attribute information combined by the combining means And a region where the shape of the spot color information and the shape of the elements constituting the image data do not match when the data amount of attribute information compressed by the compression unit exceeds a predetermined memory amount A downsampling rate of the spot color information for each of the area determination means for determining the area and the area where the shape does not match by the area determination means. Determining means for determining, down-dumping means for down-sampling the spot color information at the down-sampling rate determined by the determining means, and re-synthesizes the spot color information down-sampled by the down-dump ring means to the attribute information Recombining means, recompressing means for recompressing attribute information recombined by the recombining means, and when the data amount of attribute information compressed by the compressing means or the recompressing means is equal to or less than a predetermined memory amount And means for storing the compressed attribute information in a memory, performing image processing according to the attribute information on the image data stored in the memory, forming images of basic four colors and spot colors, and printing It is characterized by performing.

  According to the present invention, in order to reduce the capacity of attribute information to a predetermined memory amount or less, downsampling is performed on special toner information that modifies an image while downsampling special toner information to increase the compression rate of attribute information. By reducing the rate, it is possible to suppress a reduction in image quality of special toner printing due to a deviation from the image.

  Further, even if the capacity of the attribute information cannot be reduced below the predetermined memory amount while retaining the information of the special color toner, it is possible to surely print the special toner by shifting to the two-stage printing means, and Information on the special toner to be modified is printed in the first stage printing, so that it is possible to suppress the deterioration of the image quality of the special toner printing due to the deviation from the image by the two stage printing.

1 is a block diagram showing an image processing system according to the present invention. 1 is a block diagram showing an MFP according to the present invention. The figure which shows the structure of local PC102. The figure which shows the structure of the data processor 211. The figure which shows the structure of the PDL process part 401. FIG. 3 is a diagram illustrating a configuration of a scanner image processing unit 402. The figure which shows the structure of the clear image process part 406. FIG. The figure which shows the structure of the image process part 408. FIG. 6 is a flowchart showing a flow of clear printing processing. The flowchart which shows the flow of a PDL process. The figure which shows the data created with the application. The figure which shows image data. The figure which shows the signal of an attribute. The figure which shows attribute information. FIG. 6 shows a configuration of a storage device 405. The figure which showed the clear image. The flowchart which shows the flow of a clear form registration process. The flowchart which shows the flow of a clear synthetic | combination process. The figure which shows the attribute signal containing clear information. The figure which shows image data. The figure which shows clear information. The figure which shows a clear printing result. 5 is a flowchart showing the flow of a compression processing unit 404. The flowchart which shows the flow of downsampling process S2304. The figure which shows a part of clear form registered by 1200 dpi. The figure which shows a part of clear form down-sampled to 600 dpi. The figure which shows a part of clear form down-sampled to 300 dpi. 6 is a flowchart showing a flow of clear printing. The flowchart which shows the flow of 2 step | paragraph printing. The conceptual diagram which shows the data flow of a clear printing process. The conceptual diagram which shows the flow of the data of two steps printing. image data. Transparent toner data. Print result. Downsampled transparent toner data. Print result with image misalignment.

The best mode for carrying out the present invention will be described below with reference to the drawings.
In the present embodiment, a mode using a clear (transparent) toner capable of realizing high gloss of printed matter as a special toner will be described.

<Embodiment 1>
FIG. 1 is a block diagram showing an image forming apparatus according to the present invention.

  A multi-function multifunction peripheral (hereinafter referred to as MFP) 101 and 103 and a local PC 102 are connected as recording devices to a LAN 104 constructed in the office 10. MFPs 101 and 103 perform image processing on an input image read from a document image. Then, the MFP that has read the document image prints the result of the image processing.

  It is also possible for the MFP 103 to print after image processing is performed on the document image read by the MFP 101. Further, the MFPs 101 and 103 can interpret the page description language (hereinafter referred to as PDL) language transmitted from the local PC 102 and print it.

[MFP]
FIG. 2 is a diagram illustrating the MFP. In FIG. 2, an image scanner (image reading unit) 201 reads a document image and performs digital signal processing. Further, the printer unit 202 prints an image corresponding to the original image read by the image scanner 201 on a sheet in full color.

  The image scanner 201 includes a mirror surface pressure plate 200, and a document 204 on a document table glass (hereinafter referred to as a platen) 203 is irradiated with a lamp 205 and guided to mirrors 206, 207, and 208. The irradiated light forms an image on a three-line solid-state image sensor (hereinafter referred to as CCD) 210 by a lens 209, and red (R), green (G), and blue (B ) Are sent to the data processing device 211. The lamp 205 and the mirror 206 are mechanically moved in a direction perpendicular to the electric scanning (main scanning) direction of the line sensor at a speed v and the mirrors 207 and 208 are moved at a speed of 1/2 v. Is scanned (sub-scanning). Here, the document 204 is read at a resolution of 600 dpi (dots / inch) for both main scanning and sub-scanning. The read image signal is stored in the data storage unit inside the data processing device 211 as image data in units of one page of the document.

  The data processing device 211 electrically processes the image data stored therein in units of pixels, and decomposes them into magenta (M), cyan (C), yellow (Y), and black (Bk) components, and the printer. Send to part 202. Also, clear image data (CL) is generated in units of pixels inside the data processing device 211 and is similarly sent to the printer unit 202.

  The sent M, C, Y, Bk, and CL image signals are sent to the laser driver 212. The laser driver 212 modulates and drives the semiconductor laser 213 according to the transmitted image signal. The laser beam scans on the photosensitive drum 217 via the polygon mirror 214, the f-θ lens 215, and the mirror 216. Here, as with reading, both main scanning and sub-scanning are written at a resolution of 600 dpi (dots / inch).

  The rotary developing device 218 includes a magenta developing unit 219, a cyan developing unit 220, a yellow developing unit 221, a black developing unit 222, and a clear (transparent) developing unit 223. Then, the five developing units 219 to 223 alternately come into contact with the photosensitive drum 217, and the electrostatic development formed on the photosensitive drum is developed with toner of each color.

  The transfer drum 224 winds the paper supplied from the paper cassette 225 or the paper cassette 226 around the transfer drum 224, and transfers the image developed on the photosensitive drum onto the paper.

  In this manner, after the five colors CMYBk and clear (transparent) are sequentially transferred, the sheet passes through the fixing unit 227 and is discharged after the toner is fixed on the sheet.

[Local PC]
FIG. 3 is a diagram illustrating the configuration of the local PC 102.

  When the user prints data created by the application 301, the printer driver UI unit 302 transmits a print instruction to the printer driver 303. Upon receiving the print instruction, the printer driver 1803 creates PDL data from the data of the application 301. The transmission unit 304 transmits the created PDL data to the MFP 101.

[Data processing device 211]
FIG. 4 is a diagram illustrating the configuration of the data processing apparatus 211 mounted on the MFP, and includes a PDL processing unit 401, a scanner image processing unit 402, a compression processing unit 404, a data storage unit 405, a clear image processing unit 406, a UI. 407, an image processing unit 408, a print control unit 409, and a clear composition unit 410.

  FIG. 5 is a diagram illustrating a configuration of the PDL processing unit 401 in FIG. 4, which includes a reception unit 501, a PDL analysis unit 502, an image data generation unit 503, an attribute information generation unit 504, and a transmission unit 505.

  FIG. 6 is a diagram illustrating the configuration of the scanner image processing unit 402 in FIG. 4, which includes a receiving unit 601, a scan color processing unit 602, an image area determination unit 603, an attribute information generation unit 604, and a transmission unit 605. .

  FIG. 7 is a diagram illustrating a configuration of the clear image processing unit 406 in FIG. 4, which includes a reception unit 701, a gray scale processing unit 702, a binarization processing unit 703, and a transmission unit 704.

  FIG. 8 is a diagram illustrating the configuration of the image processing unit 408 in FIG. 4, and includes a data decompression unit 801, a print color conversion unit 802, a clear toner processing unit 803, an image generation unit 804, and a transmission unit 805.

[Clear print processing]
FIG. 9 is a flowchart showing the flow of the clear printing process performed by the data processing apparatus 211.

  FIG. 30 is a diagram illustrating a data flow of the clear printing process.

  First, the PDL processing unit 401 receives PDL data transmitted from the local PC 102 or the MFPs 101 and 103, analyzes the PDL data, and generates image data 3001 and attribute information 3002 in units of one page (step S901). Next, the clear combining unit 410 combines the clear form (clear information) 3003 registered in the storage device 405 and the attribute information to generate attribute information 3004 including the clear information (step S902). Next, the compression processing unit 404 compresses the image data and the attribute information so as to have a capacity equal to or less than each prescribed memory amount, and stores the compressed data in the storage device (step S903). Next, the image processing unit 408 performs image processing such as color conversion and halftone processing (step 904). The image processing unit 408 extracts and decompresses image data recorded in the storage device 405 by the decompression unit 801 and attribute information corresponding to the image data. The color processing unit 502 converts the color signal of the image data into a CMYBk signal according to the attribute information. The clear toner processing unit 803 generates clear data from the clear information from the attribute information, and sends the clear data to the print control unit 409 in the transmission unit 805. The image formation processing unit 804 performs halftone processing on the color-converted image data according to the attribute information, and generates print image data matching the output gradation of the printer unit 202. The generated print image data is sent to the print control unit 409 by the transmission unit 805. The print control unit 409 transmits print image data and clear data to the printer unit 202 (step S905). The printer unit 202 performs printing using CMYBk toner and clear toner, and outputs a printed material 3005.

  For the scanned image, the scan color processing unit 602 performs background processing and color processing on the scanned image to generate image data, and the image area determination unit 603 performs character and color / monochrome image area determination. Then, the attribute information generation unit 604 generates attribute information based on the image area determination result.

[PDL processing]
FIG. 10 is a flowchart showing the flow of PDL processing performed by the PDL processing unit 401.

  FIG. 11 shows data created by an application. The data is composed of elements of a character 1101, a graphic 1102, and a graphic 1103. When printing is instructed from the UI of the local PC 102, the local PC 102 converts it into PDL data and sends it to the MFP 101. FIG. 11 shows an example of data and is not limited to characters and figures.

  First, the PDL analysis unit 502 analyzes PDL data including each element of characters, graphics, and images, color designation, and other control commands (step 1001). Next, the image data generation unit 503 renders along the analysis contents of the PDL data, and generates image data composed of color signals such as RGB for each page (step 1002). FIG. 12 is a diagram showing image data, and data composed of the elements shown in FIG. 11 includes color signals of pixels. Next, the attribute information generation unit 504 generates attribute information corresponding to the image data from the analysis content of the PDL data and the image data (step S1003). FIG. 13 is a diagram showing attribute signals. The attribute signal indicates the attribute of the corresponding pixel. For example, bit0 indicates whether or not it is a graphic, and “1” indicates a pixel indicating a graphic, and “0” indicates a non-graphic pixel. Bit 1 indicates text or image, and bit 2 indicates chromatic or achromatic color. As described above, each bit constituting the attribute signal represents the attribute of the corresponding pixel as a bit value and is stored. FIG. 14 is a diagram showing attribute information, which is composed of attribute signals corresponding to the respective pixels of the image data of FIG.

[Storage device]
FIG. 15 is a diagram showing the configuration of the storage device 405.

  The storage device 405 includes an image data storage area 1501, an attribute information storage area 1502, and a clear form registration area 1503.

  The image data storage area 1501 is an area in which image data generated by the image data generation unit 503 of the PDL processing unit 401 or the scan color processing unit 602 of the scanner image processing unit 402 is stored. The attribute information storage area 1502 is an area in which attribute information generated by the attribute information generation unit 504 of the PDL processing unit 401 or the attribute information generation unit 604 of the scanner image processing unit 402 is recorded. The clear form registration area is an area for registering a clear form generated by a clear form registration process to be described later.

  There is a limit to the amount of memory of data that can be stored and registered in each area, and the storage device 405 performs compression processing on each data (image data, attribute information, clear form) and limits the amount of data Store as follows.

[Clear Form Registration]
The clear printing uses clear form image data registered in the clear image processing unit 406 as clear information.

  FIG. 16 shows a clear image.

FIG. 17 is a flowchart showing the flow of the clear form registration process.
When instructed to register a clear form image from a driver UI screen (not shown), the local PC 102 converts clear data 1601 into PDL data and transmits the PDL data to the PDL processing unit 901.

  First, the PDL processing unit 901 receives PDL data, and generates image data by the above-described PDL processing (step S1701). The generated image data is received by the clear image processing unit 406 (step S1702), and the gray scale processing unit 702 converts the image data into gray scale data. As an example of the conversion method, in the case of input in RGB, a case where it is converted into a YUV signal and only the Y signal is used as a gray scale signal is mentioned, but this is not restrictive. Next, the binarization processing unit 703 converts the image data converted to grayscale into binary image data (step S1704). As an example of the conversion method, a threshold value is set, and when the grayscale signal value is larger than the threshold value, it becomes 1, and when it is smaller, it becomes 0, and binary image data is generated. The transmission unit 805 transmits the binary image data to the storage device 405 and registers it as a clear form in the clear form registration area 1503 of the storage device 405 (step S1705).

[Clear composition processing]
FIG. 18 is a flowchart showing the flow of the clear composition processing by the clear composition unit 410.

  The clear composition unit 410 first receives the attribute information generated by the attribute information generation unit 504 of the PDL processing unit 401 (step S1801), and acquires the clear form registered in the clear form registration area 1503 of the storage device 405. (Step S1802). By synthesizing clear form information with the received attribute information, attribute information including the clear information is generated (step S1803). For example, when the attribute information has the attribute configuration shown in FIG. 13, the clear attribute is represented by bit6. The compositing process extracts the attribute signal (8 bits) of the attribute information at the same pixel position and the clear form value, and if the clear form value is “0” in bit 6 of the attribute information, “0” is changed to “1”. If there is, write “1”. The attribute information including the clear information is generated by writing the clear form value in the attribute signal of the attribute information for all the pixels.

  FIG. 19 shows an attribute signal including clear information.

  When the data of FIG. 16 registered as a clear form is combined with the attribute information of FIG. 14, attribute information including the clear information of FIG. 19 is generated.

[Usage of clear printing]
In clear printing, the clear toner is overwritten on the text and graphic elements that make up the image data to obtain the effect of modifying the elements, and the clear toner itself is used as a watermark text or stamp. Is printed as an image.

  20 shows image data, and FIG. 21 shows an example of clear information.

  The clear data 2101 in FIG. 21 is clear data for the purpose of modification, and is configured in the same position at the same position as the character 2001 in the elements constituting the image data in FIG. By overwriting the clear toner on the character 2001 of the image data, the character 2001 can be glossed and the effect of modifying the character can be obtained.

  The clear data 2102 in FIG. 21 is configured as an image (character) in the background area of the image data in FIG. 20, so that it is possible to obtain an effect of a watermark character that is difficult to distinguish at first glance.

  FIG. 22 shows the result of clear printing using the image data of FIG. 20 and the clear information of FIG. The character 2001 is printed with the clear data 2101 for modification overwritten with the clear toner as the modified character 2201, and the clear data 2102 for the image is printed as the watermark character 2202 with the clear toner.

[Compression processing]
Image data generated by the image data generation unit 503 and attribute information including clear information generated by the clear synthesis process 401 are stored in the image data storage area 1501 and the attribute information storage area 1502 of the storage device 405, respectively. . Each area has a limit on the amount of data that can be recorded, and image data and attribute information are subjected to compression processing in the compression processing unit 404 and stored with the data amount being equal to or less than the limit memory amount.

  The image data is compressed by irreversible JPEG compression, which is visually hardly degraded and capable of high compression, and is stored in the image data storage area 1501 with the data amount being equal to or less than the limited memory.

  In the attribute information, each bit represents each attribute, and compression by lossless compression is performed to prevent loss of the attribute.

  FIG. 23 is a flowchart showing the flow of the compression processing unit 404.

  In the attribute information compression processing by the compression processing unit 404, first, attribute information including the clear information generated by the clear combining unit 410 is acquired (step S2301), and the attribute information is subjected to data compression by Packbit compression which is lossless compression ( Step S2302). Next, it is determined whether or not the data amount of the compressed attribute information is equal to or smaller than a predetermined memory amount that is a limitation of the attribute information storage area 1502 (step S2303). If the predetermined amount of memory is exceeded, the clear information is down-sampled so as to be less than the predetermined amount of memory (step S2304), and the compressed attribute information is recorded in the attribute information recording area 1502 (step S2305). ).

  On the other hand, in step S2303, if it is less than the predetermined memory amount, the compressed attribute information is recorded in the attribute information recording area 1502 (step S2305).

[Downsampling process]
FIG. 24 is a flowchart showing the flow of downsampling processing S2304 of the compression processing unit 404. In the downsampling process, the clear form is reconstructed so as to increase the compression rate of the lossless compression of the attribute information. The clear form is reconstructed, for example, in the Packbits compression, since the compression rate increases as the same data continues, downsampling is performed to lower the data resolution of the clear form.

  In the clear information downsampling process, first, the attribute information generated by the attribute information generation unit 504 of the PDL processing unit 401 is received (step S2401), and the clear form registered in the clear form registration area 1503 of the storage device 405 is acquired. (Step S2402).

  Next, a clear area where the shape of the clear information in the clear form matches the shape of the elements constituting the image data and a clear area where they do not match are determined (step S2403). The determination of coincidence / non-coincidence is performed based on the clear attribute of bit 6 representing the clear information of the attribute signal (FIG. 13), the character / photo attribute of bit 1 representing the element of the image data, and the graphic attribute of bit 0. For example, the clear data 2101 in FIG. 21 is configured at the same position as the character 2001 of the image data in FIG. 20, and is determined to be a clear region having the same shape. The clear data 2102 in FIG. 21 does not match any element of the image data in FIG. Here, it is possible to determine that the clear area having the same shape is decoration clear data for modifying the image, and the non-matching clear area is clear data for the image such as a watermark character.

  Next, the downsampling rate is determined for each of the clear areas where the shapes of the elements constituting the image data do not match the clear areas (step S2404). For clear areas with the same shape, a small down-dumping rate is set so that the deviation between the shape of the clear information and the shape of the image data elements is minimized, and the attribute information compression rate is set for areas with inconsistent shapes. Set a large down dumpling rate to increase.

  For example, if the clear form is generated at 1200 dpi with the same resolution as the image data, the downsampling rate of the clear area where the shape matches is set to 1/2 (resolution 600 dpi), and the clear area where the shape does not match is down The sampling rate is set to 1/4 (resolution 300 dpi).

Next, according to the determined down-sampling rate, the clear area where the shapes match and the clear area where they do not match are down-sampled (step S2405).
For example, FIG. 25 shows a part (clear data) of a clear form generated and registered at 1200 dpi having the same resolution as the image data.

  In the clear area where the shape of the down dumpling rate is ½ (600 dpi resolution), the horizontal resolution of the clear data in FIG. 25 is down-sampled to 600 dpi, and the original data is simply doubled by 600 dpi data. The data is 1200 dpi (FIG. 26).

  The clear area where the shape of the down dumpling rate is 1/4 (resolution 300 dpi) does not match is obtained by down-sampling the horizontal resolution of the clear data in FIG. 25 to 300 dpi and simply multiplying the 300 dpi data by 4 times. The data is 1200 dpi (FIG. 27).

  By simply doubling and quadrupling the data, the rate at which the same data continues is increased, and the compression rate by Packbits compression can be increased.

  Next, the down-sampled clear form and attribute information are resynthesized in the same manner as the clear composition unit 410 (step S2406), the attribute information including the reconstructed clear information is compressed (step S2407), and the data amount of the compressed attribute information Is less than or equal to a predetermined memory amount that is the limit of the attribute information storage area 1502 (step S2408). If it is less than the predetermined memory amount, the clear holding flag indicating whether or not the clear information is held in the attribute information is turned on (held) (step S2409), and the clear information down-sampling process is terminated.

  On the other hand, if the predetermined amount of memory is exceeded in step S2408, the clear information is deleted from the attribute information and recompression is performed (step S2410), and the clear holding flag is turned OFF (not held) (step S2410). S2411), the attribute information changing process is terminated.

  As described above, in order to reduce the data amount of the attribute information to a predetermined memory amount or less, it is possible to increase the compression rate of the attribute information while holding the clear information by down-sampling the clear information, It is possible to improve the ratio at which printing of basic four colors and clear toner can be performed. For clear information that modifies an image, it is possible to suppress a decrease in image quality by reducing the downsampling rate.

<Embodiment 2>
In the first embodiment, the clear information is down-sampled in order to reduce the data amount of the attribute information to a predetermined memory amount or less. However, in the second embodiment, after the down-sampling process is performed, the attribute information data is reduced. A form of the clear printing process when the amount exceeds a predetermined memory amount will be described.

[Clear printing process 2]
FIG. 28 is a flowchart showing the flow of the clear printing process performed by the data processing apparatus 211.

  First, the PDL processing unit 401 receives PDL data transmitted from the local PC 102 or the MFPs 101 and 103, analyzes the PDL data, and generates image data and attribute information for each page (step S2801). Next, the clear combining unit 410 combines the clear form (clear information) registered in the storage device 405 and the attribute information to generate attribute information including the clear information (step S2802). Next, the compression processing unit 404 compresses the image data and the attribute information so as to have a capacity equal to or less than the prescribed memory amount, and stores the compressed data in the storage device (step S2803).

  Next, it is determined whether the clear hold flag set in the downsampling process S2304 of the compression processing unit 404 is “ON” or “OFF” (step 2804). “ON” of the clear holding flag indicates that the attribute information in which the attribute information changing process holds the clear information is stored in the attribute information storage area 1502, and “OFF” indicates that the attribute information in which the clear information is deleted is stored in the attribute information. It indicates that it is stored in area 1502.

If the clear hold flag is “ON” in step S2804,
By acquiring image data 3001 recorded in the storage device 405 and attribute information 3004 including clear information and performing image processing, basic four-color print image data and clear data are generated (step S2805). The print control unit 409 transmits the generated basic four-color print image data and clear data to the printer unit 202 (step S2806). The printer unit 202 performs printing using CMYBk toner and clear toner, and outputs a printed material 3005.

  On the other hand, if the clear hold flag is “OFF” in step S2804, a two-step printing process (step S2807) is performed.

[Two-stage printing process]
FIG. 29 is a flowchart showing the flow of the two-stage printing process S2807.

  FIG. 31 is a diagram showing a data flow of the two-stage printing process.

  In the two-step printing process, first, similarly to step S2403, a clear area where the shape of the clear information in the clear form 3103 and the shape of the elements constituting the image data match and a clear area where they do not match are determined (step S2901). The clear form 3103 is divided into a clear area 1 (3104) that matches and a clear area 2 (3105) that does not match (step S2902).

  Next, the attribute information 3102 and the clear data (3104) of the clear area 1 are combined to generate attribute information including the clear data of the clear area 1 (step S2903), and the generated attribute information is compressed (S2904).

  Image processing is performed from the attribute information including the image data 3101 recorded in the storage device 405 and the clear data (3104) of the clear area 1 to generate print image data of the basic four colors and the clear data of the clear area 1 (step S2905). . The print control unit 409 transmits the generated print image data of the four basic colors and the clear data of the clear area 1 to the printer unit 202, performs printing with the four basic colors of CMYBk toner and the clear toner, and outputs a printed material 3106 ( Step S2906).

  Next, the printed material 3106 is set again in the paper cassette 225 of the MFP 101 or the paper feed stage of the paper cassette 226 (step S2907). Next, clear data 3105 in the clear area 2 is acquired (step S2908), and the clear data 3105 in the clear area 2 is transmitted to the printer unit 202 as image data. The printer unit 202 prints only the clear toner on the printed material 3106, and outputs the printed material 3107 (step S2909).

  As described above, even when the capacity of attribute information cannot be reduced to a predetermined memory amount or less, the two-step printing process enables clear printing with certainty, and the clear information for modifying the image is the first step. By performing printing in printing, it is possible to suppress a decrease in image quality of clear printing due to a deviation from an image by two-stage printing.

Claims (3)

In an image forming apparatus capable of printing using a special color toner in addition to the basic four colors of cyan, magenta, yellow and black,
It has attribute information for each pixel of the image data and the image data,
Means (405) for storing the image data in a memory;
Combining means (410) for combining spot color information with each pixel of the attribute information;
Compression means (404) for compressing attribute information synthesized by the synthesis means;
When the data amount of attribute information compressed by the compression unit exceeds a predetermined memory amount,
A region determination means (S2403) for determining a region that does not match a region where the shape of the spot color information and the shape of the elements constituting the image data match;
Determining means (S2404) for determining a downsampling rate of the spot color information for each of the areas that do not match the areas whose shapes match by the area determination means;
Down-dampling means (S2405) for down-sampling the spot color information at the down-sampling rate determined by the determining means;
Recombining means (S2406) for recombining the spot color information downsampled by the down dumpling means with the attribute information;
Recompression means (S2407) for recompressing the attribute information recombined by the recomposition means;
Means for storing the compressed attribute information in a memory (S2305) when the data amount of the attribute information compressed by the compression unit or the recompression unit is equal to or less than a predetermined memory amount;
An image forming apparatus that performs image processing according to the attribute information on the image data stored in the memory, forms images of four basic colors and special colors, and performs printing.   The determining means uses a downsampling rate of spot color information of an area that matches the shape of an element constituting the image data, based on a downsampling rate of spot color information of an area that does not match the shape of an element constituting the image data. The image forming apparatus according to claim 1, wherein the image forming apparatus is made smaller. When the data amount of attribute information compressed by the recompression unit exceeds a predetermined memory amount,
A dividing unit (S2902) for dividing the spot color information into a first region that matches a shape of an element constituting the image data and a second region that does not match a shape of the element constituting the image data;
Second synthesis means (S2903) for synthesizing the spot color information of the first region and the attribute information;
Second compression means (S2904) for compressing the attribute information synthesized by the second synthesis means;
Means for storing in the memory the attribute information compressed by the second compression means (S2305), and performing image processing according to the attribute information on the image data stored in the memory to form images of four basic colors and special colors First printing means (S2906) for performing printing,
A two-stage printing unit (S2909) is provided that prints only the spot color on the printed matter printed by the first printing unit based on the spot color information of the second area by the second printing unit that prints the spot color. The image forming apparatus according to claim 1.

Images