JP2004053959A - Color image forming apparatus and color image forming system - Google Patents

Abstract

An object of the present invention is to enable a long image to be formed by removing limitations imposed by the length of an intermediate transfer member.
When a long image exceeding the maximum image formation length of an intermediate transfer member is formed on a recording medium, a long toner image is formed on a photosensitive member while primary-transferring to the intermediate transfer member and recording is performed. Secondary transfer to a medium. Then, the printing color is switched, the sheet is fed again to the printing position, and the primary transfer and the secondary transfer of the next color are performed. For example, when the secondary transfer of black (K) is completed, the recording medium is fed again to the printing position, and the primary transfer and secondary transfer of cyan (C) of the next color are performed. Hereinafter, magenta (M) and yellow (Y) are processed similarly. In the long printing mode, the secondary transfer is performed only for the printing color, and the toner images of each color are superimposed on the recording medium, not on the intermediate transfer body.
[Selection diagram] FIG.

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a color image forming apparatus and a color image forming system capable of forming a color image, such as a laser printer, a copying machine, and a facsimile machine.
[0002]
[Prior art]
A color image forming apparatus employing an electrophotographic method such as a color laser printer uses a tandem type in which a photoconductor for each color is arranged close to the periphery of an intermediate transfer body, or uses a single photoconductor while switching for each color. Single drum system. In either method, an image is formed by the following steps.
[0003]
First, a drum-shaped photoconductor is charged, and a predetermined portion of the charged photoconductor is exposed to laser light or the like, thereby forming an electrostatic latent image expressed by the presence or absence of surface charges. Next, toner is attracted to the electrostatic latent image and developed to generate a visible image. Then, after this visible image is primarily transferred to a belt-shaped intermediate transfer body, it is secondarily transferred to a recording medium such as printing paper or an OHP sheet, and the recording medium is heated to fuse the toner, thereby recording. Fix the image on the medium.
[0004]
For example, when a color image is generated using four printing colors of cyan (C), magenta (M), yellow (Y), and black (K), a visible image of each color is formed on a photoconductor, and the intermediate image is formed. The images are sequentially transferred to a transfer member, and a visible image of each color is superimposed on the intermediate transfer member to form a color image. Then, finally, the secondary transfer is performed only once to form a color image on the recording medium.
[0005]
In the tandem system, since the photoconductors for each color are operated in parallel, the printing speed can be increased, but the manufacturing cost increases. In the single-drum system, the manufacturing cost can be suppressed, but the printing time increases.
[0006]
[Problems to be solved by the invention]
In a conventional color image forming apparatus, particularly a single-drum type, a visible image of each color is temporarily superimposed on an intermediate transfer body to form a color image, and finally transferred to a recording medium. Therefore, the length of the image that can be formed depends on the length of the intermediate transfer member. That is, since a color image longer than the length of the intermediate transfer member cannot be formed, the printable size is limited.
[0007]
Therefore, for example, when a long print such as a poster or a banner is to be performed, it is necessary to previously form the intermediate transfer member to be longer than the length of the long recording medium. When the length of the intermediate transfer member is increased, waste during normal printing increases, and the circulating time of the intermediate transfer member also increases, so that the printing speed decreases.
[0008]
The present invention has been made in view of the above-described problems, and has as its object to provide a color image forming apparatus and a color image forming system capable of forming a color image longer than the length of an intermediate transfer member. It is in.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, a color image forming apparatus according to the present invention includes an image generating unit, a determining unit, and a control unit.
[0010]
The image generating means generates print image data based on the print data. The determination unit compares the print image length of the print image data with the maximum image formation length of the intermediate transfer member, and determines whether the print image length is the first print mode in which the print image length is equal to or less than the maximum image formation length, or It is determined whether the present mode is the second print mode exceeding the maximum image formation length. When it is determined that the print mode is the first print mode, the control unit forms a color image by superimposing a visible image of each color on the intermediate transfer body, and transfers the color image to a recording medium. If it is determined that the print mode is set, the visible image formed on the intermediate transfer body is transferred to a recording medium for each color, and a color image is formed on the recording medium.
[0011]
More specifically, in the second print mode, the control unit repeatedly feeds the recording medium to the print position a number of times corresponding to the number of colors based on the print data, and controls the visualization of each color formed on the intermediate transfer body. By transferring the images to the recording medium, a color image is formed on the recording medium.
[0012]
That is, for example, when three colors of CMY are used, first, a cyan image is formed on a photoconductor, firstly transferred to an intermediate transfer body, and the cyan image transferred to the intermediate transfer body is secondarily transferred to a recording medium. . By continuously forming and transferring the remaining cyan image to the recording medium while cleaning the photoconductor and the intermediate transfer body, the entirety of the cyan image having a longer dimension than the intermediate transfer body is transferred to the recording medium. Next, the recording medium to which the cyan image has been transferred is re-fed to the printing position, and the magenta image is transferred onto the recording medium in the same manner as described above. Then, the recording medium on which the cyan image and the magenta image are superimposed and transferred is again fed to the printing position, and finally, the yellow image is superimposed and transferred, thereby forming a color image on the recording medium. When three colors are used as process colors, refeeding is performed twice (the number of feedings is three). When four colors are used as process colors, refeeding is performed three times (the number of feedings is four). “The number of times according to the number of colors based on print data” means, for example, that even if four process colors are prepared, if only yellow and black are used for printing, two-color printing is performed. Just means refeeding.
[0013]
Note that re-feeding may be performed manually using a manual feed tray, or re-feeding means of a double-sided printing mechanism may be used.
[0014]
In one embodiment of the present invention, a means for positioning a recording medium re-fed to a printing position is provided.
[0015]
For example, a mark for positioning is printed on the print surface margin or the back surface of the recording medium, and the mark is detected by a position detection sensor such as a photoelectric sensor. Drop can be prevented.
[0016]
In one embodiment of the present invention, the image generating means generates the print image data using an error diffusion method.
[0017]
By using the error diffusion method as a screen for half-toning, it is possible to form a color image without significantly deteriorating the quality even if some misalignment occurs.
[0018]
The print data can be generated in advance in accordance with either the first print mode or the second print mode.
[0019]
That is, a print data generation device such as a personal computer or a digital camera can generate print data corresponding to a print mode in advance and transmit the print data to the color image forming device. Conversely, print data having a common structure can be generated in each print mode, and the image generation unit can convert the print data into print image data corresponding to each print mode.
[0020]
In another aspect of the present invention, when it is determined that the print mode is the second print mode, the control unit divides the print image data into a plurality of divided images each having a length equal to or less than the maximum image forming length. For each divided image, a visible image of each color is superimposed on the intermediate transfer member to form a color image, which is transferred to a recording medium.
[0021]
That is, a long print image is divided by a length equal to or less than the maximum image forming length, and a color image is formed on an intermediate transfer body for each divided image and transferred to a recording medium. That is, the operation is the same as repeating the first print mode by the number of image divisions.
[0022]
In this case, it is preferable to set the boundary line of each divided image at a location that has little effect on the image quality.
[0023]
For example, when a catch phrase or the like composed of multi-colored characters is printed on a banner or a banner, dividing the image between the characters can reduce the influence on the image quality. Also, in a case where a plurality of reduced images are printed on a roll paper in a line, the images may be divided between the images.
[0024]
The present invention can be understood as a color image forming system and a program. The program can be stored in various recording media such as a flexible disk (FD), a compact disk (CD-ROM, CD-R), a hard disk (HD), and a memory, and is distributed via a communication line. You can also.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS.
[0026]
1. First Embodiment [0027]
First, a first embodiment of the present invention will be described with reference to FIGS. The host computer 1 is realized, for example, as a personal computer, a workstation, a digital camera, a portable information terminal, a mobile phone, or the like. The host computer 1 includes, for example, an application program 2 such as an image processing program and a document creation program; a printer driver 3 for converting document data such as characters and images transferred from the application program 2 into predetermined print data; (Hereinafter, abbreviated as “I / F”) 4 for performing data communication with the device.
[0028]
In printing, the user selects data to be printed, and also performs various printing such as printing paper size, paper feeding method, paper discharging method, double-sided printing or single-sided printing, the number of prints, and color printing or monochrome printing. Settings are to be made. Note that these print settings are merely examples, and the user does not need to set all of the above items.
[0029]
The printer driver 3 generates print data based on print settings specified by the user. The generated print data is transmitted from the storage device of the host computer 1 to the printer 10 via the I / F 4. The host computer 1 and the printer 10 may be formed separately, or may be integrated like a color copying machine or a color multifunction peripheral. The host computer 1 and the printer 10 may be connected by a cable such as a serial transmission cable or a parallel transmission cable, or may be connected by infrared rays, radio waves, or the like.
[0030]
The printer 10 includes a printer controller 20 and a print engine 30. The printer controller 20 includes an I / F 21, a reception buffer 22, an image generation unit 23, an output buffer 24, and a control unit 25.
[0031]
The print data transmitted from the I / F 4 of the host computer 1 is stored in the reception buffer 22 via the I / F 21. The image generation unit 23 reads the print data stored in the reception buffer 21 and generates print image data in accordance with the print settings specified by the control unit 25. Then, the generated print image data is input to the engine control unit 50 of the print engine 30 via the output buffer 24. Here, the image generating unit 23 performs a halftoning process that is relatively resistant to positional deviation, such as an error diffusion method, in order to reduce the influence of positional deviation due to a plurality of secondary transfers described later.
[0032]
The print engine 30 is roughly composed of a latent image forming system, a developing system, a transfer system, and a transport system. The developing unit 31 is formed as a rotary developing unit in which developing units of respective colors of CMYK are arranged in a ring.
[0033]
The surface of the photoconductor 32 is uniformly charged at a predetermined voltage, and a laser unit 33 serving as an exposure unit scans the surface of the charged photoconductor with laser light based on image data for printing. By scanning, an electrostatic latent image of each color plane is formed.
[0034]
The latent image formed on the photoconductor 32 is developed by the developing unit 31 to become a toner image. The toner image on the surface of the photoconductor 32 is primarily transferred to the intermediate transfer body 34. The intermediate transfer body 34 is formed in a belt shape, and is wound around a drive roller 35, a primary transfer roller 36, an idler roller 37, a secondary transfer opposing roller 38, and a tension roller 39.
[0035]
The intermediate transfer member 34 is rotated by a driving roller 35, and the toner image on the photosensitive member 32 is transferred to the intermediate transfer member 34 by a primary transfer roller 36 provided so as to sandwich the intermediate transfer member 34 with the photosensitive member 32. The primary transfer is performed. After transferring the toner image to the intermediate transfer body 34, the photoconductor 32 is cleaned by the photoconductor cleaner 41, and the residual toner is removed.
[0036]
The toner image transferred to the intermediate transfer body 34 is secondarily transferred by a secondary transfer roller 40 to a recording medium PM such as printing paper. That is, as the recording medium PM passes between the secondary transfer roller 40 and the opposing roller 38, the toner image on the intermediate transfer body 34 is transferred to the surface of the recording medium PM by electrostatic force. After the completion of the secondary transfer, the surface of the intermediate transfer member 34 is cleaned by the intermediate transfer member cleaner 42.
[0037]
Next, focusing on the recording medium PM, the recording medium PM is inserted in a direction indicated by an arrow F1 from a manual feed tray or a sheet feeding cassette, and is conveyed by a sheet feeding roller 43 in a direction indicated by an arrow F2 toward a printing position. The leading end of the recording medium PM is detected by the sheet detection sensor 44, and thereby the start of feeding of the recording medium PM is detected.
[0038]
The toner image on the intermediate transfer member 34 is transferred to the recording medium PM by the secondary transfer roller 40. When the recording medium PM on which the secondary transfer has been performed passes between the fixing roller 45 and the pressing roller 46, the toner of the transferred toner image is fused to the medium surface, and the image is fixed. After the image is fixed, the recording medium PM is transported in the direction indicated by the arrow F3, and is discharged to a paper discharge tray.
[0039]
Although the above is the operation when printing on one side, the print engine 30 includes a double-sided transport mechanism. When forming an image on the other surface of the recording medium PM, the recording medium PM on which image formation on one side is completed is conveyed in the direction of arrow R1 via the re-feeding path 47, and is moved from the direction of arrow R2. It leads to an inversion path 48. Then, the recording medium PM is taken out from the reversing path 48 in the direction of arrow R3 and placed on the re-feeding path 47, whereby the recording medium PM is turned over. By transporting the recording medium PM in the direction of arrow R4 and returning it to the paper feeding position, an image can be formed on the unprinted surface through the same process as described above. In addition, by moving the re-feeding path 47 without passing through the reversing path 48, the recording medium PM can be transported again to the printing position without changing the surface of the recording medium PM.
[0040]
The engine control unit 50 controls the operations of the above-described units based on the print image data and the print settings.
[0041]
Next, the operation of the image forming process will be described with reference to FIGS. The features of this processing include a normal print mode for forming an image that is shorter than the maximum image formation length of the intermediate transfer body 34, and a long print mode for forming an image that exceeds the maximum image formation length. The point is that the operation of the print engine 30 is changed. Note that the flowchart shown in the figure shows an outline of the operation, and is different from an actual program. Steps are abbreviated as “S”.
[0042]
First, FIG. 2 shows a print data generation process executed by the printer driver 3 of the host computer 1.
[0043]
When the user instructs printing, the printer driver 3 acquires data of a document to be printed from the application program 2 (S1). The document data is characters, images, graphics, or a mixture thereof.
[0044]
Further, the printer driver 3 acquires various print settings specified by the user or initialized (S2). The print settings include, for example, print size, number of copies, normal print mode or long print mode, single-sided print or double-sided print, color print or monochrome print, enlarged print or reduced print, and the like.
[0045]
Next, the printer driver 3 compares the length of the print image of the document to be printed (print image length) with the maximum length of the toner image that can be formed on the intermediate transfer member 34 (maximum image formation length) (S3). .
[0046]
If the print image length is equal to or less than the maximum image formation length of the intermediate transfer member 34 (S4: NO), the normal print mode is used, in which an image can be formed on the recording medium PM by one secondary transfer, so that the normal print mode is used. Print data is generated (S5) and transmitted to the printer 10 (S6). On the other hand, if the print image length exceeds the maximum image formation length (S4: YES), the print data for the long print is set in the long print mode in which the image is formed on the recording medium PM by performing the secondary transfer a plurality of times. Is generated (S7) and transmitted to the printer 10 (S6).
[0047]
Next, FIG. 3 is a flowchart showing an outline of a printing process executed by the printer 10.
[0048]
The printer controller 20 monitors whether print data has been received from the host computer 1 (S11). When print data is received from the host computer 1, it is determined whether or not the printing mode is the long printing mode (S12).
[0049]
In the case of the normal print mode, a latent image is formed on the photoconductor 32 and then developed (S13), and the visualized toner image is primarily transferred to the intermediate transfer body 34 (S14). When the primary transfer of the first color is completed, the photoconductor 32 is cleaned and switched to the second color (S15, S16), a toner image of the second color is formed, and the primary transfer is overlaid on the intermediate transfer body. (S13, S14). By repeating the primary transfer process for the number of colors used for printing, a color image is formed on the intermediate transfer body 34. Then, the color image obtained by superimposing the toner images of all colors is secondarily transferred to the recording medium PM (S17). After the secondary transfer, the image is fixed on the recording medium PM by the fixing roller 45, and the process is terminated by discharging the paper (S18).
[0050]
On the other hand, in the case of the long printing mode (S12: YES), the first color toner image is formed on the photoconductor 32 (S21), and the toner image is primary-transferred to the intermediate transfer body 34 (S22). The toner image on the body 34 is secondarily transferred to the recording medium PM (S23). Here, in the long printing mode, since an image longer than the maximum image forming length of the intermediate transfer body 34 is formed, the primary transfer of each color is not completed once, and the primary transfer of each color is performed a plurality of times. Is performed (S24). When the primary transfer is performed a plurality of times for the same color, a portion where the transfer has been completed is cleaned, and a toner image of a subsequent portion is newly formed to continue the transfer. The portion secondarily transferred to the recording medium PM is fixed by the fixing roller 45 (S25).
[0051]
Next, the recording medium PM on which the secondary transfer of the first color has been completed on the image forming surface is re-fed through the re-feeding path 47 (S26), and reaches the printing start position based on the detection signal of the detection sensor 44. It is determined whether or not it has been performed (S27). At the time of re-feeding, re-feeding is performed using only the re-feeding path 47 without passing through the reversing path 48. Here, the positioning can be performed by various methods using the detection sensor 44. For example, positioning may be performed by detecting the leading end of the recording medium PM, or a positioning mark such as a registration mark may be formed in a blank portion of the recording medium PM and the positioning may be performed by detecting the positioning mark. You can also.
[0052]
Until the secondary transfer of all colors is completed (S28), the above process is repeated while switching the printing colors (S29) (S21 to S27). That is, the recording medium PM is fed by the number of printing colors, and is secondarily transferred for each color, so that a color image is formed.
[0053]
The image forming processes in the normal print mode and the long print mode described above will be described again with reference to the schematic diagrams of FIGS.
[0054]
FIG. 4 shows an image forming process in the normal print mode. In the normal print mode, a toner image is formed for each color on the photoconductor 32 and primary-transferred to the intermediate transfer member 34, and a toner image of all colors is superimposed on the intermediate transfer member 34 to form a color image. Is secondarily transferred to the recording medium PM. In the normal print mode, the secondary transfer is completed once.
[0055]
FIG. 5 shows an image forming process in the long printing mode. In the long printing mode, a long toner image is primarily transferred to the intermediate transfer body 34 while being formed on the photoconductor 32, and is secondarily transferred to the recording medium PM. Then, the printing color is switched, the sheet is fed again to the printing position, and the primary transfer and the secondary transfer of the next color are performed. That is, in the long printing mode, the secondary transfer for the printing color is performed, and the toner images of each color are superimposed on the recording medium PM, not on the intermediate transfer body 34.
[0056]
According to the present embodiment, a long image exceeding the maximum image formation length of the intermediate transfer body 34 can be formed, and the usability for the user can be improved.
[0057]
Further, in the long printing mode, only the image forming process is changed, and the printing mechanism used in the normal printing mode is used as it is. Therefore, for example, the intermediate transfer body 34 can be formed long, or the intermediate transfer body for long printing can be used. There is no need to separately prepare and switch the body, and long printing can be performed without increasing the manufacturing cost.
[0058]
In the present embodiment, a print image is generated for each color plane, and primary transfer is performed for each color plane. However, the operation of generating an image of each color plane from print data is performed by the printer driver 3. This may be performed by the image generation unit 23 of the printer controller 20.
[0059]
2. Second Embodiment
Next, a second embodiment of the present invention will be described with reference to FIGS. The feature of the present embodiment is that, when performing long printing, a long printing image is divided into a plurality of images in the longitudinal direction, and each divided image is formed in the same process as in normal printing. Hereinafter, a description will be given mainly of a newly added or changed portion.
[0061]
FIG. 6 shows print data generation processing on the printer driver side according to the present embodiment. In this processing, when the long print mode is designated (S4: YES), the print data of the document to be printed is The print image is divided into a plurality of pieces so that the print image is equal to or less than the maximum image formation length of the intermediate transfer body 34 (S31).
[0062]
Next, the image dividing position is corrected, and the dividing position is moved to a place where the image quality is not affected (S32). In order to divide a long print image into a plurality of divided images, if an image is interrupted between the divided images, the image quality may be reduced in some cases.
[0063]
This will be further described with reference to FIG. FIG. 7A is an example of an image to be printed in a long form, and is composed of only characters. This long image is divided into four images by the maximum image forming length of the intermediate transfer member 34, as shown as "image division (before correction)" in the figure. However, the boundary between the second divided image and the third divided image and the boundary between the third divided image and the fourth divided image straddle the characters “to” and “i”, respectively. Therefore, if the image is interrupted even by one dot line in the middle of the character, the appearance is reduced.
[0064]
Therefore, as shown as "image division (after correction)" in the figure, the initial boundary lines across the characters are shifted by ΔL1 and ΔL2, respectively, and are corrected so as to be located in the non-printing portion between the characters. .
[0065]
As shown in FIG. 7B, not only in the case of characters alone, but also in the case of printing a plurality of image objects side by side, if the image is divided by the gap between the image objects, the image quality is not reduced. Long printing can be performed.
[0066]
Next, FIG. 8 is a flowchart showing a printing process of the printer according to the present embodiment.
[0067]
In the case of the long printing mode (S12: YES), a process similar to the image forming process in the normal printing mode is repeated for each divided image. That is, for each divided image, the toner image of each color is superimposed on the intermediate transfer body 34 for primary transfer (S41 to S44), and after secondary transfer to the recording medium PM, the image is fixed (S46).
[0068]
Next, the fixing roller 45 is moved backward to stop heating the recording medium PM. The heat generation itself of the fixing roller 45 may be stopped or the temperature may be lowered.
[0069]
Then, until the image formation is completed for all the divided images (S48), the above-mentioned steps are repeated and the images are formed (S41 to S47) while switching the divided images (S49).
[0070]
FIG. 9 is a schematic diagram showing a state of the image forming process according to the present embodiment. For each of the divided images, a toner image of each color is superimposed on the intermediate transfer body 34 and primary-transferred, and the resulting color image is secondary-transferred to the recording medium PM.
[0071]
In the present embodiment configured as described above, similarly to the above-described embodiment, a long image can be formed by removing the limitation imposed by the length of the intermediate transfer body 34.
[0072]
It should be noted that those skilled in the art can make various additions and changes within the scope of the present invention described in each of the above embodiments.
[0073]
For example, the mechanism of the print engine is not limited to the illustrated one, and each developing unit may be separately arranged, or a belt-shaped photoconductor may be used instead of the drum-shaped photoconductor.
[0074]
【The invention's effect】
As described above, according to the color image forming apparatus and the color image forming system of the present invention, a color image longer than the length of the intermediate transfer body can be formed, and the usability of the user can be improved without significantly increasing the manufacturing cost. be able to.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating an overall outline of a color image forming system according to a first embodiment of the present invention.
FIG. 2 is a flowchart illustrating print data generation processing on the printer driver side.
FIG. 3 is a flowchart illustrating a printing process performed by a printer.
FIG. 4 is a schematic diagram illustrating an image forming process in a normal print mode.
FIG. 5 is a schematic diagram illustrating an image forming process in a long printing mode.
FIG. 6 is a flowchart illustrating print data generation processing according to a second embodiment of the present invention.
FIG. 7 is an explanatory diagram showing a state in which a long print image is divided into a plurality of images with a maximum image forming length of an intermediate transfer member.
FIG. 8 is a flowchart illustrating a printing process.
FIG. 9 is a schematic diagram illustrating an image forming process in a long printing mode.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 host computer 2 application program 3 printer driver 4 interface 10 printer 20 printer controller 21 interface 22 reception buffer 23 image generation unit 24 output buffer 25 control unit 30 print engine 31 developing unit 32 photoconductor 33 laser unit 34 intermediate transfer body 35 driving roller 36 Primary transfer roller 37 Idler roller 38 Secondary transfer facing roller 39 Tension roller 40 Secondary transfer roller 41 Photoconductor cleaner 42 Intermediate transfer body cleaner 43 Feed roller 44 Paper detection sensor 45 Fixing roller 46 Pressure roller 47 Re-feed Path 48 Reverse path 50 Engine control unit PM Recording medium

Claims (10)

In a color image forming apparatus that forms a latent image on an image carrier based on input print data and transfers a visible image obtained by developing the latent image to a recording medium via an intermediate transfer body,
Image generating means for generating print image data based on the print data,
A print image length of the print image data is compared with a maximum image formation length of the intermediate transfer member, and the print image length is the first print mode in which the print image length is equal to or less than the maximum image formation length, or the print image length is A determination unit that determines whether the second print mode is longer than the maximum image formation length,
When it is determined that the printing mode is the first printing mode, a color image is formed by superimposing a visible image of each color on the intermediate transfer body, and the color image is transferred to the recording medium. Control means for transferring the visible image formed on the intermediate transfer body to the recording medium for each color when it is determined that the printing mode is set, and forming a color image on the recording medium. A color image forming apparatus. In the second print mode, the control unit repeatedly feeds the recording medium to a print position a number of times corresponding to the number of colors based on the print data, and outputs a visible image of each color formed on the intermediate transfer body. The color image forming apparatus according to claim 1, wherein a color image is formed on the recording medium by transferring the image data to the recording medium. 3. The color image forming apparatus according to claim 2, further comprising means for positioning the recording medium re-fed to the printing position. The color image forming apparatus according to claim 3, wherein the image generating unit generates the print image data using an error diffusion method. The color image forming apparatus according to claim 4, wherein the print data is generated in advance in accordance with one of the first print mode and the second print mode. In a color image forming apparatus that forms a latent image on an image carrier based on input print data and transfers a visible image obtained by developing the latent image to a recording medium via an intermediate transfer body,
Image generating means for generating print image data based on the print data,
A print image length of the print image data is compared with a maximum image formation length of the intermediate transfer member, and the print image length is the first print mode in which the print image length is equal to or less than the maximum image formation length, or the print image length is A determination unit that determines whether the second print mode is longer than the maximum image formation length,
When it is determined that the printing mode is the first printing mode, a color image is formed by superimposing a visible image of each color on the intermediate transfer body, and the color image is transferred to the recording medium. When it is determined that the print mode is set, the print image data is divided into a plurality of divided images each having a length equal to or less than the maximum image forming length, and each of the divided images is provided on the intermediate transfer body. Control means for forming a color image by superimposing the visible images and transferring the color image to the recording medium. The color image forming apparatus according to claim 6, wherein a boundary line of each of the divided images is set at a location having little effect on image quality. A host computer that generates multi-color print data, and a recording medium that forms a latent image on an image carrier based on the print data and develops the latent image through an intermediate transfer body A color image forming system comprising:
The host computer,
The print image length calculated based on the instructed print setting is compared with the maximum image formation length of the intermediate transfer body, and the first print mode in which the print image length is equal to or less than the maximum image formation length is determined. Or a determination unit that determines whether the print image length is a second print mode that exceeds the maximum image formation length,
If it is determined that the print mode is the first print mode, print data for the first print mode is generated. If it is determined that the print mode is the second print mode, print data for the second print mode is generated. Print data generating means,
The color image forming apparatus,
Image generation means for generating print image data based on print data input from the host computer,
When printing in the first print mode, a color image is formed by superimposing a visible image of each color on the intermediate transfer body, and the color image is transferred to the recording medium. When printing, there is provided a control unit that transfers the visible image formed on the intermediate transfer body to the recording medium for each color and forms a color image on the recording medium. Color image forming system. A host computer that generates multi-color print data, and a recording medium that forms a latent image on an image carrier based on the print data and develops the latent image through an intermediate transfer body A color image forming system comprising:
The host computer,
The print image length calculated based on the instructed print setting is compared with the maximum image formation length of the intermediate transfer body, and the first print mode in which the print image length is equal to or less than the maximum image formation length is determined. Or a determination unit that determines whether the print image length is a second print mode that exceeds the maximum image formation length,
If it is determined that the print mode is the first print mode, print data for the first print mode is generated. If it is determined that the print mode is the second print mode, the print data has a length equal to or less than the maximum image formation length. Print data generating means for generating print data for the second print mode comprising a plurality of divided images,
The color image forming apparatus,
Image generation means for generating print image data based on print data input from the host computer,
When printing in the first print mode, a color image is formed by superimposing a visible image of each color on the intermediate transfer body, and the color image is transferred to the recording medium. When printing, for each of the divided images, control means for superimposing a visible image of each color on the intermediate transfer body to form a color image and transferring the color image to the recording medium is provided. Image forming system. A program that generates print data for printing by a color image forming apparatus that transfers a visible image formed on an image carrier to a recording medium via an intermediate transfer body,
The print image length calculated based on the instructed print setting is compared with the maximum image formation length of the intermediate transfer body, and the first print mode in which the print image length is equal to or less than the maximum image formation length is determined. Or a function of determining whether the print image length is the second print mode exceeding the maximum image formation length,
If it is determined that the print mode is the first print mode, print data for the first print mode is generated. If it is determined that the print mode is the second print mode, print data for the second print mode is generated. Function and
A program to be implemented on a computer.

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