JP2015226307A - Image processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing device that enhances convenience when diazo-like printing is performed by a printing device.SOLUTION: In a case where image data of a print target is monochromatic image data and an instruction of executing diazo-like printing is received, a print image data generator 82 generates drop data in which an image portion of the monochromatic image data is changed to diazo color when a sheet supply unit 2 holds a diazo-like sheet. Furthermore, in a case where image data of a print target is monochromatic image data and an instruction of executing diazo-like printing is received, the print image data generator 82 generates drop data in which an image portion of the monochromatic image data is changed to diazo color and also a diazo-like base is provided when the sheet supply unit 2 does not hold any diazo-like sheet.

Description

  The present invention relates to an image processing apparatus that generates print image data used for printing in a printing apparatus.

  2. Description of the Related Art A diazo copying machine that forms an image using the photosensitivity and coupling reactivity of a diazonium salt is known (for example, see Patent Document 1). The printed matter produced by the diazo type copier turns blue. For this reason, copying by a diazo copying machine is called blue printing.

  By the way, in a printer other than a diazo copying machine, for example, an ink jet printing apparatus, printing may be performed so as to obtain a blue print (diazo style) printed matter by a diazo copying machine. Such printing is called diazo-style printing.

  As a diazo style printing method, there is a method of printing on a dedicated diazo style paper based on monochrome image data. In this case, the monochrome image portion in the monochrome image data is colored in a diazo color. The diazo-style paper is a paper whose background color is diazo. The diazo color is a color that reproduces the color of blue.

Japanese Patent Laid-Open No. 2000-221652

  In a printing apparatus that performs diazo-style printing by the above-described method, the user needs to prepare a dedicated diazo-style paper in advance, which is not convenient.

  The present invention has been made in view of the above, and an object of the present invention is to provide an image processing apparatus capable of improving convenience when performing diazo-style printing with a printing apparatus.

  In order to achieve the above object, a first feature of an image processing apparatus according to the present invention is a printing apparatus that holds at least one type of paper including white paper and applies a color material to the paper to allow printing in a diazo color. An image processing apparatus that generates print image data in a format used for printing in the printer, and includes a print image data generation unit that generates print image data in a format used for printing in the printing apparatus based on image data to be printed The print image data generation unit, when the image data to be printed is monochrome image data and has received a diazo-style print execution instruction, and the printing apparatus holds diazo-style paper, If print image data is generated by changing the image portion of the monochrome image data to diazo color, and the printer does not hold diazo-style paper, An image portion in the image data is to generate print image data assigned with underlying diazo style with change diazo color.

  A second feature of the image processing apparatus according to the present invention is that the printing apparatus prints a diazo color using a plurality of color materials including cyan, and the print image data generation unit includes the print target. When the image data is monochrome image data and a diazo-style printing execution instruction is received and the printing apparatus does not hold diazo-style paper, only the cyan color material is printed on the diazo-style background. It is to generate print image data to be used.

  According to the first feature of the image processing apparatus of the present invention, the print image data generation unit is configured to print the print apparatus when the image data to be printed is monochrome image data and has received a diazo-style print execution instruction. In the case of holding a diazo-style paper, print image data in which the image portion in the monochrome image data is changed to a diazo color is generated. When the printing apparatus does not hold diazo-style paper, the print image data generation unit changes the image portion in the monochrome image data to a diazo color and generates print image data with a diazo-like background. Accordingly, even when the printing apparatus does not hold the diazo-style paper, it is possible to automatically perform the diazo-style printing on the white background paper. Therefore, it is not always necessary to prepare the diazo-style paper. Therefore, the convenience at the time of performing diazo style printing can be improved.

  According to the second feature of the image processing apparatus of the present invention, the print image data generation unit receives the diazo-style print execution instruction when the image data to be printed is monochrome image data, and the print apparatus In the case where the wind paper is not held, print image data using only cyan color material is generated for printing the background of the diazo style. Thereby, the consumption of a color material can be suppressed by not using a color material other than cyan for printing the background.

1 is a schematic configuration diagram of an inkjet printing apparatus according to an embodiment. It is a control block diagram of the inkjet printing apparatus which concerns on embodiment. It is a block diagram which shows the structure of an image process part. It is a figure which shows the input / output characteristic in a default gamma correction table. It is a figure which shows the input-output characteristic in the gamma correction table for diazo coloring. It is explanatory drawing with coloring by the gamma correction for diazo coloring. It is a flowchart of a diazo style printing process. It is a flowchart of a diazo style printing process.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Throughout the drawings, the same or equivalent parts and components are denoted by the same or equivalent reference numerals. However, it should be noted that the drawings are schematic and different from the actual ones. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  Further, the embodiment shown below exemplifies an apparatus or the like for embodying the technical idea of the present invention, and the technical idea of the present invention is the material, shape, structure, and arrangement of each component. Etc. are not specified below. The technical idea of the present invention can be variously modified within the scope of the claims.

  FIG. 1 is a schematic configuration diagram of an ink jet printing apparatus provided with an image processing apparatus according to an embodiment of the present invention. FIG. 2 is a control block diagram of the ink jet printing apparatus shown in FIG. FIG. 3 is a block diagram illustrating a configuration of the image processing unit. In the following description, the direction orthogonal to the paper surface of FIG. 1 is the front-rear direction, and the front surface direction is the front. Also, the top, bottom, left, and right of the paper surface in FIG.

  In FIG. 1, a path indicated by a thick line is a transport path through which a sheet as a print medium is transported. Among the transport routes, a route indicated by a solid line is a normal route RC, a route indicated by a one-dot chain line is a reverse route RR, a route indicated by a broken line is a paper discharge route RD, and a route indicated by a two-dot chain line is a paper feed route RS. In the following description, upstream and downstream mean upstream and downstream in the transport path.

  As shown in FIGS. 1 and 2, the inkjet printing apparatus 1 according to the present embodiment includes a paper feeding unit 2, a transport printing unit 3, an upper surface transport unit 4, a paper discharge unit 5, and a reversing unit 6. The image reading unit 7, the storage unit 8, the operation panel unit 9, the control unit 10, and a housing 11 that stores or holds each unit.

  The paper feeding unit 2 holds at least one type of paper including white paper whose background color is white, and feeds the held paper P. The paper feed unit 2 is arranged on the most upstream side of the transport path. The paper feed unit 2 includes an external paper feed base 21, an external paper feed roller 22, a plurality of internal paper feed stands 23, a plurality of internal paper feed rollers 24, a plurality of pairs of vertical transport rollers 25, and a registration roller 26. With.

  The external paper feed tray 21 is used for loading paper P used for printing. The external paper feed tray 21 is partly exposed outside the housing 11.

  The external paper feed roller 22 takes out the paper P one by one from the external paper feed tray 21 and conveys it toward the registration rollers 26 along the paper feed path RS. The external paper feed roller 22 is driven by a motor (not shown).

  The internal paper feed table 23 is used for loading paper P used for printing. The internal paper feed table 23 is disposed inside the housing 11.

  The internal paper feed roller 24 takes out the paper P one by one from the internal paper feed tray 23 and sends it out to the paper feed path RS. The internal paper feed roller 24 is driven by a motor (not shown).

  The vertical conveyance roller 25 conveys the paper P taken out from the internal paper feed table 23 toward the registration roller 26. The vertical conveyance roller 25 is disposed along the paper feed path RS. The vertical conveying roller 25 is driven by a motor (not shown).

  The registration roller 26 temporarily stops the paper P conveyed from the external paper feed tray 21, the internal paper feed tray 23, and the reversing unit 6, and then transports the paper P to the transport printing unit 3. The registration roller 26 is disposed on the normal route RC in the vicinity of the junction point between the sheet feeding route RS and the reverse route RR. The registration roller 26 is driven by a motor (not shown).

  The transport printing unit 3 prints an image on the paper P while transporting the paper P fed by the paper feeding unit 2. The conveyance printing unit 3 includes a belt conveyance unit 31 and a printing unit 32.

  The belt transport unit 31 transports the paper P transported from the registration rollers 26 while being sucked and held on the belt. The belt conveyance unit 31 is driven by a motor (not shown).

  The printing unit 32 performs printing by applying ink (corresponding to the color material in claims) to the paper P. The printing unit 32 includes inkjet heads 36A and 36B, ink cartridge mounting units 37A and 37B, and ink cartridges 38C and 38M. In addition, the alphabetic suffixes in the reference numerals of the inkjet heads 36A and 36B, the ink cartridge mounting portions 37A and 37B, and the ink cartridges 38C and 38M may be omitted and collectively described.

  The ink jet heads 36A and 36B discharge ink supplied from the ink cartridges 38 mounted on the ink cartridge mounting portions 37A and 37B, respectively. The inkjet head 36 has a plurality of nozzles arranged along a direction (front-rear direction) orthogonal to the transport direction of the paper P, and ejects ink from the nozzles. In the inkjet head 36, the number of ink droplets (number of drops) ejected from one nozzle to one pixel can be changed, and gradation printing that expresses the density by the number of drops is performed. The ink jet head 36 is supplied with ink from an ink cartridge 38 via an ink path (not shown). The inkjet heads 36 </ b> A and 36 </ b> B are arranged in parallel along the conveyance direction (left-right direction) of the paper P above the belt conveyance unit 31.

  The ink cartridge mounting portion 37 is for mounting the ink cartridge 38. The ink cartridge mounting portion 37 is configured such that the ink cartridge 38 can be attached and detached.

  The ink cartridge 38 contains ink used for printing. The ink cartridges 38C and 38M contain cyan (C) and magenta (M) ink, respectively. The ink cartridge 38 can be attached to and detached from the ink cartridge mounting portion 37.

  Here, at the time of manufacture, the ink jet printing apparatus 1 has the ink cartridges 38K and 38R mounted on the ink cartridge mounting portions 37A and 37B, respectively. The ink cartridges 38K and 38R contain black (K) and red (R) inks, respectively. That is, the inkjet printing apparatus 1 is manufactured as a KR two-color machine capable of performing pseudo color printing with black ink and red ink.

  By replacing the ink cartridges 38K and 38R installed at the time of manufacture with the ink cartridges 38C and 38M, the inkjet printing apparatus 1 is changed to a CM two-color machine capable of diazo-style printing with cyan ink and magenta ink. Yes. In diazo printing, diazo printing is performed with cyan ink and magenta ink. The diazo color is a color that reproduces the color of blue printing by a diazo copying machine.

  The upper surface transport unit 4 transports the paper P transported by the belt transport unit 31 in a U-turn from the right direction to the left direction. The upper surface transport unit 4 includes a plurality of pairs of upper surface transport rollers 41.

  The upper surface transport roller 41 transports the paper P along the transport path. The pair of uppermost transport rollers 41 on the most downstream side is disposed in the upstream part of the reversing path RR. The other upper surface transport rollers 41 are arranged along a normal path RC between the belt transport unit 31 and the paper discharge unit 5. The upper surface transport roller 41 is driven by a motor (not shown).

  The paper discharge unit 5 discharges the printed paper P. The paper discharge unit 5 includes a switching unit 46, a paper discharge roller 47, and a paper discharge table 48.

  The switching unit 46 switches the transport path of the paper P between the paper discharge path RD and the reverse path RR. The switching unit 46 is disposed at a branch point between the paper discharge route RD and the reverse route RR. The switching unit 46 is driven by a solenoid (not shown).

  The paper discharge roller 47 conveys the paper P guided to the paper discharge path RD by the switching unit 46 and discharges it to the paper discharge table 48. The paper discharge roller 47 is disposed between the switching unit 46 and the paper discharge table 48 along the paper discharge path RD. The paper discharge roller 47 is driven by a motor (not shown).

  The paper discharge table 48 is for stacking printed paper P discharged by the paper discharge roller 47. The paper discharge table 48 has a tray shape protruding from the housing 11 and is inclined.

  The reversing unit 6 reverses the single-side printed paper P and conveys it to the registration roller 26 during double-sided printing. The reversing unit 6 includes a reversing roller 51, a switchback unit 52, a refeed roller 53, and a switching gate 54.

  The reverse roller 51 temporarily transports the paper P transported by the upper surface transport roller 41 of the upper surface transport unit 4 to the switchback unit 52 and then transports it to the refeed roller 53. The reversing roller 51 is arranged on a reversing path RR between the most downstream upper surface conveying roller 41 and the carry-in port of the switchback unit 52. The reverse roller 51 is driven by a motor (not shown).

  The switchback unit 52 is a space for the reversing roller 51 to temporarily carry in the paper P. The switchback portion 52 is formed at the lower part of the paper discharge table 48. The switchback portion 52 is opened in the vicinity of the reversing roller 51 for carrying the paper P therein.

  The refeed roller 53 transports the paper P transported by the reversing roller 51 to the registration roller 26. The refeed roller 53 is disposed on the reverse path RR between the reverse roller 51 and the registration roller 26. The refeed roller 53 is driven by a motor (not shown).

  The switching gate 54 guides the paper P conveyed by the upper surface conveyance roller 41 to the reverse roller 51. Further, the switching gate 54 guides the paper P carried out from the switchback unit 52 by the reversing roller 51 to the refeed roller 53. The switching gate 54 is disposed in the vicinity of the center of gravity at the three locations of the uppermost transport roller 41, the reverse roller 51, and the refeed roller 53.

  The image reading unit 7 includes a document table, a light receiving element, a light source, a lens, a scanning mechanism, an automatic document feeder (not shown), etc., and optically reads an image of the document and generates RGB format image data. To do.

  The storage unit 8 includes an HDD (Hard Disk Drive) or the like. The storage unit 8 stores various programs.

  The storage unit 8 stores a color profile for KR. The color profile for KR indicates a correspondence relationship when the RGB value of each pixel in the image data to be printed in the RGB format is converted to the black and red values.

  The storage unit 8 stores the KR color profile because the inkjet printing apparatus 1 is manufactured as a KR two-color machine as described above. In the inkjet printing apparatus 1, by replacing black with cyan and red with magenta, the KR color profile is used for printing in two colors, cyan and magenta.

  The storage unit 8 stores a default gamma correction table and a diazo coloring gamma correction table. The gamma correction table is used for gamma correction by a gamma correction unit 92 described later. The diazo coloring gamma correction table is used when diazo printing is performed based on monochrome image data. In other cases, the default gamma correction table is used.

  The default gamma correction table holds the input / output characteristics shown in FIG. As shown in FIG. 4, the default gamma correction table is a table in which the input value and the output value are the same. In other words, the default gamma correction table does not change the density of the image data.

The diazo coloring gamma correction table holds input / output characteristics for each color of R (red), G (green), and B (blue) shown in FIG. By such gamma correction using the diazo coloring gamma correction table, the achromatic color represented by the point A at the center of the a ^* b ^* plane of the L ^* a ^* b ^* color system shown in FIG. It becomes a diazo color represented by point B in the color gamut. That is, the achromatic color in the monochrome image data can be colored into a diazo color by the diazo coloring gamma correction table.

  The operation panel unit 9 displays various input screens and accepts input operations by the user. The operation panel unit 9 includes a display unit 61 and an input unit 62.

  The display unit 61 displays images such as various input screens. The display unit 61 includes a liquid crystal display panel and the like.

  The input unit 62 receives an input operation by the user and outputs an operation signal corresponding to the operation. The input unit 62 includes various operation keys, a touch panel, and the like.

  The control unit 10 performs control processing in the inkjet printing apparatus 1. The control unit 10 includes a CPU, a RAM, a ROM, and the like. The control unit 10 includes a conveyance control unit 71, an image reading control unit 72, an image processing unit (corresponding to an image processing apparatus in claims) 73, a print control unit 74, and a display control unit 75. Each unit of the control unit 10 is configured by the CPU operating according to a program stored in the storage unit 8 or the like.

  The conveyance control unit 71 controls conveyance of the paper P by the paper feeding unit 2, the belt conveyance unit 31, the upper surface conveyance unit 4, the paper discharge unit 5, and the reversing unit 6.

  The image reading control unit 72 controls the image reading unit 7 to read the image of the document.

  The image processing unit 73 generates drop data that is print image data in a format used for printing by the inkjet head 36 based on the image data to be printed input from the image reading unit 7. The drop data is data indicating the number of ink drops of each color ejected to each pixel. As shown in FIG. 3, the image processing unit 73 includes a determination unit 81 and a print image data generation unit 82.

  The determination unit 81 determines whether the image data to be printed is diazo image data or monochrome image data at the time of printing with the diazo-style print setting.

  Here, the inkjet printing apparatus 1 can perform diazo-style printing with diazo-style print settings. The user can set the diazo print setting by operating the input unit 62. A document to be copied in the diazo-style print setting is a diazo document or a monochrome document. The diazo manuscript includes a blue-printed manuscript by a diazo copying machine and a manuscript that is a printed matter by diazo-like printing by the inkjet printing apparatus 1.

  The diazo image data is image data generated by reading the above-described diazo document by the image reading unit 7. The diazo image data is image data in which image portions such as characters and illustrations are diazo color and the background portion is also light diazo color. The monochrome image data is image data generated by reading a monochrome document by the image reading unit 7.

  When the normal print setting is used instead of the diazo print setting, the determination unit 81 does not determine the image data to be printed, and outputs the image data to the gamma correction unit 92 described later.

  The print image data generation unit 82 generates drop data based on the image data to be printed. The print image data generation unit 82 includes a background cut unit 91, a gamma correction unit 92, a diazo background application unit 93, a color conversion processing unit 94, and a screening processing unit 95.

  The background cut unit 91 performs background cut processing when the image data to be printed in diazo-style printing is monochrome image data.

  The gamma correction unit 92 performs gamma correction on the image data. In the diazo-style print setting, when the image data to be printed is monochrome image data, the gamma correction unit 92 applies to image portions (other than the background portion) such as characters and illustrations in the monochrome image data after the background cut processing. Perform gamma correction for diazo coloring. The diazo coloring gamma correction is a gamma correction based on the diazo coloring gamma correction table shown in FIG.

  In the diazo-style print setting, when the image data to be printed is diazo image data, the gamma correction unit 92 performs default gamma correction on the diazo image data. The default gamma correction is a gamma correction based on the default gamma correction table shown in FIG.

  Further, when the normal print setting is used instead of the diazo print setting, the gamma correction unit 92 performs default gamma correction on the image data to be printed.

  The diazo background imparting unit 93 is an image after gamma correction when the image data to be printed is monochrome image data in the diazo style print setting, the paper feeding unit 2 has no diazo style paper, and the designated background color is diazo color. Add a diazo background to the data. The designated background color is the diazo-style background color to be added to the image data when the image data to be printed is monochrome image data, and there is no diazo-style paper in the paper supply unit 2 and white paper is used for printing. Is the color specified as.

  Here, in the diazo-style print setting, when the image data to be printed is monochrome image data, if the diazo-style paper is held in the paper feeding unit 2, the diazo-style paper is used for printing. If there is no diazo-style paper in the paper supply unit 2, white paper is used for printing. As described above, the white background paper is held in the paper feeding unit 2.

  In the diazo-style print setting, when the image data to be printed is monochrome image data and white paper is used for printing, a diazo-style background is added. As the diazo-like background, either a diazo-colored background or a cyan single-colored background can be designated. By the user's operation on the input unit 62, either a diazo-colored background or a cyan single-colored background is designated as the designated background color of the diazo-like background.

  The color conversion processing unit 94 performs color conversion processing for converting image data in RGB format into image data in a color representation format (CM format) using two colors of cyan and magenta. The color conversion processing unit 94 converts the image data in the RGB format into the CM format by using the color profile for KR stored in the storage unit 8 by replacing black with cyan and red with magenta. In the diazo-style print setting, when the image data to be printed is monochrome image data, the paper feed unit 2 has no diazo-style paper, and the designated background color is a single cyan color, the color conversion processing unit 94 determines the background portion. The cyan value (density) is set to a predetermined value, and the magenta value (density) is set to zero.

  The screening processing unit 95 performs screening processing on the image data after the color conversion processing to generate drop data. The screening process is a process that performs error diffusion processing, halftone processing, and the like.

  The print control unit 74 controls the printing unit 32 to print on the paper P. Specifically, the print control unit 74 drives the inkjet heads 36A and 36B to discharge ink based on the drop data generated by the image processing unit 73.

  The display control unit 75 controls the display unit 61 to display an image.

  Next, a diazo style printing process in the inkjet printing apparatus 1 will be described.

  7 and 8 are flowcharts of the diazo-style printing process. The processing in the flowcharts of FIGS. 7 and 8 is started when the user sets a document on the image reading unit 7 and instructs execution of diazo printing by an operation on the input unit 62 when diazo printing is set. . Here, as described above, the original to be copied in the diazo-style print setting is a diazo original or a monochrome original.

  In step S <b> 1 of FIG. 7, the image reading control unit 72 causes the image reading unit 7 to read an image of a document. The image reading unit 7 generates image data of the read original. This image data is image data of 8 bits (256 gradations) for each color of RGB. If the original is a diazo original, diazo image data is generated. If the original is a monochrome original, monochrome image data is generated.

  Next, in step S <b> 2, the determination unit 81 determines whether the image data to be printed generated by the image reading unit 7 is diazo image data or monochrome image data.

  Specifically, the determination unit 81 obtains a hue from the RGB values for each pixel in the image data, and determines whether each pixel is included in a predetermined color gamut based on the hue. The predetermined color gamut is a color gamut set as a diazo color gamut. The determination unit 81 counts the number of pixels included in the predetermined color gamut. The determination unit 81 determines that the image data to be printed is diazo image data when the count value is equal to or greater than the threshold value, and the image data to be printed is monochrome image data when the count value is less than the threshold value. Is determined.

  Next, in step S3, the determination unit 81 determines whether the image data to be printed is diazo image data based on the determination result in step S2.

  When it is determined that the image data to be printed is diazo image data (step S3: YES), in step S4, the determination unit 81 outputs the image data to be printed to the gamma correction unit 92 and performs default gamma correction. Let it be done. The gamma correction unit 92 outputs the image data after the gamma correction to the color conversion processing unit 94.

  Next, in step S5, the color conversion processing unit 94 performs color conversion processing for converting the image data after the gamma correction from the RGB format to the CM format.

  Next, in step S <b> 6, the screening processing unit 95 performs screening processing on the image data after the color conversion processing to generate drop data.

  Next, in step S <b> 7, the conveyance control unit 71 and the print control unit 74 execute printing on white paper.

  Specifically, the transport control unit 71 feeds the paper P to the paper feeding unit 2 from the paper feeding base on which the white paper is set among the external paper feeding base 21 and the plurality of internal paper feeding bases 23, and supplies the paper P to the paper feeding section 2. The paper P is transported by the belt transport unit 31. The print control unit 74 drives the inkjet heads 36 </ b> A and 36 </ b> B based on the drop data to print on the paper P conveyed by the belt conveyance unit 31.

  The printed paper P is conveyed from the belt conveyance unit 31 to the upper surface conveyance unit 4, and is conveyed by the upper surface conveyance roller 41 in the upper surface conveyance unit 4. The paper P is guided from the normal route RC to the paper discharge route RD by the switching unit 46 of the paper discharge unit 5, and is discharged to the paper discharge table 48 by the paper discharge roller 47.

  If it is determined in step S3 that the image data to be printed is monochrome image data (step S3: NO), in step S8, the determination unit 81 determines whether or not diazo-style paper is held in the paper feed unit 2. Judging.

  When it is determined that the diazo-style paper is held in the paper feed unit 2 (step S8: YES), in step S9, the determination unit 81 outputs the image data to be printed to the base cut unit 91, and the base cut processing is performed. To do.

  Here, when the image data to be printed is monochrome image data, the background portion is white. However, in monochrome image data generated by reading a monochrome document with the image reading unit 7, the background portion is white, but its density is not necessarily zero. On the other hand, the background cut unit 91 performs background cut processing on the image data to be printed. Specifically, the background cut unit 91 sets each RGB value to zero in each pixel in which each RGB value (density) in the image data is equal to or less than a threshold value.

  Next, in step S10, the gamma correction unit 92 performs gamma correction for diazo coloring on the image portion (other than the background portion) of the image data after the background cut processing. The gamma correction unit 92 outputs the image data after the gamma correction to the color conversion processing unit 94.

  Next, in step S11, the color conversion processing unit 94 performs color conversion processing for converting the image data after the gamma correction from the RGB format to the CM format.

  Next, in step S12, the screening processing unit 95 performs screening processing on the image data after the color conversion processing to generate drop data.

  Next, in step S13, the conveyance control unit 71 and the print control unit 74 execute printing on diazo-style paper.

  Specifically, the conveyance control unit 71 causes the paper feeding unit 2 to feed the paper P from a paper feeding table on which diazo-style paper is set among the external paper feeding table 21 and the plurality of internal paper feeding tables 23. The fed paper P is transported by the belt transport unit 31. The print control unit 74 drives the inkjet heads 36 </ b> A and 36 </ b> B based on the drop data to print on the paper P conveyed by the belt conveyance unit 31.

  If it is determined in step S8 that the diazo-style paper is not held in the paper feed unit 2 (step S8: NO), in step S14 of FIG. 8, the determination unit 81 determines whether the designated background color is a diazo color. Determine whether.

  If it is determined that the designated background color is a diazo color (step S14: YES), in step S15, the determination unit 81 outputs the image data to be printed to the background cut unit 91 to perform the background cut process.

  Next, in step S <b> 16, the gamma correction unit 92 performs gamma correction for diazo coloring on the image portion (other than the background portion) of the image data after the background cut processing.

  Next, in step S <b> 17, the diazo background applying unit 93 adds a diazo background to the image data after the gamma correction. Specifically, the diazo background applying unit 93 sets RGB values corresponding to the diazo color for the pixels of the background portion in the image data.

  Next, in step S <b> 18, the color conversion processing unit 94 performs color conversion processing for converting the image data after the diazo color background is added from the RGB format to the CM format.

  Next, in step S19, the screening processing unit 95 performs screening processing on the image data after the color conversion processing, and generates drop data.

  Next, in step S20, the conveyance control unit 71 and the print control unit 74 execute printing on white paper.

  If it is determined in step S14 that the designated background color is a single cyan color (step S14: NO), in step S21, the determination unit 81 outputs the image data to be printed to the background cut unit 91, and performs background cut processing. Let it be done.

  Next, in step S22, the gamma correction unit 92 performs gamma correction for diazo coloring on the image portion (other than the background portion) of the image data after the background cut processing.

  Next, in step S <b> 23, the color conversion processing unit 94 performs color conversion processing for providing a cyan monochrome background. Specifically, the color conversion processing unit 94 performs color conversion processing for converting the RGB portion into the CM format for the image portion. For the background portion, the color conversion processing unit 94 sets the cyan value (density) of each pixel to a predetermined value and sets the magenta value (density) to zero.

  Next, in step S24, the screening processing unit 95 performs screening processing on the image data after the color conversion processing to generate drop data.

  Next, in step S25, the conveyance control unit 71 and the print control unit 74 execute printing on white paper.

  When the image data to be printed is diazo image data by the diazo style printing process as described above, the print image data generation unit 82 generates drop data for performing diazo style printing on white paper based on the diazo image data. (Steps S4 to S6). Then, printing based on the drop data is executed on the white background paper (step S7). As a result, a diazo-like printed matter can be obtained by copying the diazo document onto a white background paper.

  When the image data to be printed is monochrome image data and the paper feed unit 2 holds diazo-style paper, the print image data generation unit 82 changes the image portion in the monochrome image data to diazo color. Drop data is generated (steps S9 to S12). Then, printing based on the drop data is performed on the diazo-style paper (step S13). As a result, the image portion of the monochrome original is changed to a diazo color, and a diazo-like printed matter in which the background portion is expressed by the ground color of the diazo-style paper is obtained.

  When the image data to be printed is monochrome image data and the paper feed unit 2 does not hold diazo-style paper, the print image data generation unit 82 changes the image portion in the monochrome image data to diazo color. At the same time, drop data with a diazo-like background is generated (steps S15 to S19, S21 to S24). Then, printing based on the drop data is performed on the white background paper (steps S20 and S25). As a result, the diazo-like printed matter can be obtained by printing the image portion of the monochrome original changed to the diazo color and the diazo-like background on the white background paper.

  As described above, in the inkjet printing apparatus 1, when the image data to be printed for diazo printing is monochrome image data and the paper feed unit 2 holds diazo paper, the print image data generation unit 82. Generates drop data in which the image portion of the monochrome image data is changed to a diazo color. And based on this drop data, it prints on a diazo style paper. When the image data to be printed in diazo printing is monochrome image data and the paper feed unit 2 does not hold diazo paper, the print image data generation unit 82 converts the image portion in the monochrome image data to diazo. Drop data with a diazo-like background added to the color is generated. And based on this drop data, it prints on a white background paper.

  Thereby, in the case where the image data to be printed in diazo-style printing is monochrome image data, even if there is no diazo-style paper in the inkjet printing apparatus 1, it is possible to automatically perform diazo-style printing on white paper. It is not always necessary to prepare diazo-style paper. Therefore, according to the inkjet printing apparatus 1, a user's effort at the time of performing diazo style printing can be reduced, and the convenience can be improved.

  Further, when the image data to be printed for diazo-style printing is monochrome image data and the paper feed unit 2 does not hold diazo-style paper, and the designated base color is a single cyan color, the print image data generation unit 82. Generates drop data that uses only cyan ink for printing on a diazo-like background. Thereby, ink consumption can be suppressed by not using magenta ink for printing on the background.

  In the above embodiment, the case where printing is performed by the copy function as diazo-style printing has been described. However, the present invention is also applicable to the case where printing is performed by the printer function based on print data input from an external personal computer (PC). Is applicable. In this case, image data in bitmap format generated based on PDL (Page Description Language) format print data is image data to be printed.

  Further, the same processing as that of the image processing unit 73 in the above embodiment may be performed by a printer driver of a PC.

  In the above-described embodiment, the inkjet printing apparatus 1 using two colors of cyan and magenta for printing has been described. However, the number and combination of ink colors are not limited thereto. The present invention is also applicable to a printing apparatus that uses a color material other than ink.

  The present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiments. For example, some components may be deleted from all the components shown in the embodiment.

DESCRIPTION OF SYMBOLS 1 Inkjet printing apparatus 2 Paper feed part 3 Conveyance printing part 4 Upper surface conveyance part 5 Paper discharge part
DESCRIPTION OF SYMBOLS 6 Inversion part 7 Image reading part 8 Memory | storage part 9 Operation panel part 10 Control part 36,36A, 36B Inkjet head 71 Conveyance control part 72 Image reading control part 73 Image processing part 74 Print control part 81 Judgment part 82 Print image data generation part 91 Substrate cutting unit 92 Gamma correction unit 93 Diazo background applying unit 94 Color conversion processing unit 95 Screening processing unit

Claims (2)

An image processing apparatus that holds at least one type of paper including white paper, generates print image data in a format used for printing in a printing apparatus capable of printing in a diazo color by applying a color material to the paper,
A print image data generation unit that generates print image data in a format used for printing in the printing apparatus based on image data to be printed;
The print image data generation unit
When the image data to be printed is monochrome image data and a diazo-style printing execution instruction is received and the printing apparatus holds diazo-style paper, the image portion in the monochrome image data is diazo-colored. If the printing device does not hold diazo-style paper, the image portion in the monochrome image data is changed to diazo color and print image data with a diazo-like background is generated. An image processing apparatus. The printing apparatus is for printing a diazo color using a plurality of color materials including cyan,
The print image data generation unit, when the image data to be printed is monochrome image data, has received a diazo-style print execution instruction, and the printing apparatus does not hold diazo-style paper, The image processing apparatus according to claim 1, wherein print image data that uses only a cyan color material for printing the background of the image is generated.