JP2002014513A - Color image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optimum color image forming device having high throughput and capable of controlling printing without page-outstripping in monochrome and full color coexisting printing. SOLUTION: In this color image forming device, toner images having different colors are successively formed on a photosensitive body, successively transferred to an intermediate transfer body and superposed on the intermediate transfer body, and then the toner image on the intermediate transfer body is collectively transferred to recording material. When the intermediate transfer body has peripheral length long enough to hold plural toner images on the specified recording material and the plural toner images can be formed on the intermediate transfer body, the images are consecutively formed on the intermediate transfer body in the case of the plural toner images on the intermediate transfer body having the specified monochromatic color, and the images are formed at different image forming positions on the intermediate transfer body in a state where they are made different by specified rotation in the case of the plural toner images on the intermediate transfer body having the color other than the specified monochromatic color or two or more colors.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image forming apparatus using an intermediate transfer system in an electrophotographic system such as a copying machine, a printer and a facsimile, and more particularly to a color image forming apparatus for forming a plurality of images on an intermediate transfer member. The present invention relates to an image forming method.

[0002]

2. Description of the Related Art In a conventional color image forming apparatus, in particular, a color image forming apparatus capable of printing A3 size or more, a plurality of images are formed on a photoconductor, a transfer drum or an intermediate transfer body in order to print a full-color image at high speed. Has been proposed.

As disclosed in Japanese Patent Application Laid-Open No. 2000-47452, such a color image forming apparatus has an intermediate transfer member having a sufficiently long circumference capable of forming two sheets of images by A4 size lateral conveyance. In the case where the first image (first sheet) and the second image (second sheet) are formed, the second image formation is performed in accordance with the image processing time with respect to the first image formation. A color image forming apparatus that delays formation and improves throughput has been proposed.

[0004]

However, in the color image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 2000-47452, no consideration is given to the case where monochrome and full-color printing are mixed. When the image is mixed, for example, when the preceding image is four colors and the subsequent image is one color, the image output of the image created later with respect to the preceding image may overtake,
There is a problem that the page order is shifted.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has been made in view of the above-described problems. Accordingly, it is possible to perform monochrome and full-color printing while maintaining a high throughput in forming a plurality of images on an intermediate transfer member. It is an object of the present invention to propose a color copying apparatus which is optimal even when mixed and does not lower the throughput, and which can print the page order correctly.

In order to solve the above-mentioned problems, in a first means of the present invention, toner images of different colors are sequentially formed on one or a plurality of photoconductors, and the toner images are sequentially transferred to an intermediate transfer member. In a color image forming apparatus for transferring a toner image on the intermediate transfer member to a recording material at a time after forming an image on the intermediate transfer member in a superimposed manner, the intermediate transfer member may be provided on a predetermined recording material by a plurality of sheets. The intermediate image has a peripheral length capable of holding the toner image, and when a plurality of toner images on the intermediate transfer body have a specific single color, the toner images formed on the photoconductor are continuously formed. And forming an image on the intermediate transfer member by transferring the toner image on the intermediate transfer member. If the toner images of the plurality of sheets on the intermediate transfer member are other than a specific single color or two or more colors, the same image formed on the photoreceptor is used. Making the color toner image differ from the predetermined number of rotations of the intermediate transfer member. Formed at a timing wherein the transfer to the image formed on the intermediate transfer body. With this configuration, even if monochrome and full-color printing are mixed, print control without page overtaking is possible.
A high-throughput color image forming apparatus can be provided.

According to a second aspect of the present invention, when a plurality of toner images are formed on the intermediate transfer member, the image forming cycle of the plurality of toner images is the same. I do. With such a configuration,
Printing control without page overtaking becomes possible.

The third means of the present invention is characterized in that a specific single color can be selected when a specific single color toner image is formed on the intermediate transfer member. By adopting such a configuration, a specific single-color image can be printed at a high speed, and other specific single-color images can take a long time to form an image, thereby improving color development and giving a margin to the stirring ability of the developing device. be able to.

According to a fourth aspect of the present invention, when a plurality of toner images other than a specific single color or two or more colors are formed on the intermediate transfer member, a plurality of toner images are formed on the intermediate transfer member. A plurality of image formation determining means for determining whether an image can be formed on the toner image; if the plurality of image formation determining means determines that a plurality of toner images can be formed, a plurality of toner images are formed on the intermediate transfer body; When it is determined that image formation of a plurality of toner images is not possible, the next image is formed at a position where image formation of the intermediate transfer body is possible after image formation of the preceding toner image is completed. Is formed as an image. With such a configuration, it is possible to optimally determine the image formation of a plurality of images, and to provide a color image forming apparatus with high throughput.

According to a fifth aspect of the present invention, the plurality of image formation determination means determines a plurality of image formation start criteria for each of a plurality of toner images; An image forming state determining unit that determines a toner image forming state on a transfer body; and an image forming condition determining unit that determines whether an image forming condition of a new toner image is satisfied, wherein the intermediate transfer is performed by the image forming state determining unit. When an image is formed on the body, and the image formation condition of the next toner image is satisfied by the image formation condition determination means based on the image formation start reference determined by the image formation start reference determination means of the next toner image. And determining that a plurality of toner images can be formed on the intermediate transfer member. With such a configuration, it is possible to optimally determine the image formation of a plurality of images, and to provide a color image forming apparatus with high throughput.

According to a sixth aspect of the present invention, in the case where toner images having different cycles are continuously formed on the intermediate transfer member, the image on the intermediate transfer member immediately after the completion of image formation of the preceding toner image is provided. It is characterized in that an image of the next toner image is formed at a position where it can be formed. With this configuration, it is possible to perform print control without overtaking a page even in printing in different cycles in which monochrome and full color are mixed, and a high-throughput color image forming apparatus can be provided.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a view schematically illustrating a color image forming apparatus of the present invention. Reference numeral 1 denotes a color image forming apparatus main body. 2 is a photosensitive drum, which is OPC or a-Si
A photoreceptor is used. Reference numeral 3 denotes a charging roller, which is configured to be able to apply a predetermined bias voltage to the surface of the photosensitive drum 2 from a power source (not shown). Reference numeral 4 denotes an exposure unit that irradiates image information from an external terminal to the charged surface of the photosensitive drum 1 with a laser beam to form a latent image. In this case, L
ED light may be used.

Reference numeral 5 denotes a developing device for developing a color toner on the formed latent image, a developing device 5a for developing yellow, a developing device 5b for developing magenta, and a cyan developing device from the upstream side in the rotation direction of the photosensitive member 2. A developing unit 5c and a developing unit 5d for developing black are arranged. Each developing device 5 has a toner container 50a containing yellow toner and a developing container 51a for developing toner supplied by a supply roller 52a.
And a toner container 50 containing magenta toner.
b and a developing container 51b for developing toner supplied by the supply roller 52b, a toner container 50c containing cyan toner and a developing container 51c for developing toner supplied by the supply roller 52c, and further containing black toner. A developing container 51d for developing the toner supplied by the supplied toner container 50d and the supply roller 52d is disposed above the color image forming apparatus. A non-magnetic toner is used as the toner of each color of the present invention. Reference numeral 31 denotes a cleaning unit, which removes toner that has not been transferred on the intermediate transfer drum 6 described below from the photosensitive drum 2.

Reference numeral 6 denotes an intermediate transfer drum, which performs a color transfer by repeating the operation of temporarily transferring the toner developed on the photosensitive drum 2 by applying a predetermined bias for each toner. 6a is a secondary transfer roller, 6b
Denotes a cleaning roller. Although not shown, the secondary transfer roller 6a and the cleaning roller 6b are provided with a retracting mechanism for retracting from the intermediate transfer drum 6 until the respective colors are completely overlapped.

Reference numeral 7 denotes a paper feed unit, which is a paper feed unit that has a large amount of paper stacked under the color image forming apparatus 1 and that conveys the uppermost paper by a paper feed roller 70.
a and a manual feed unit for transporting sheets one by one. The sheet fed from the sheet feeding means 7 is conveyed to the registration roller 60, and after leading edge alignment and timing, the sheet is sent to the secondary transfer roller 6 a at the timing of the toner superimposed on the intermediate transfer drum 6. After the transfer, the sheet is conveyed toward the exit side by the conveyance belt 8. Reference numeral 9 denotes a fixing unit, which is disposed near the exit side and fixes the secondary-transferred toner to the sheet by heat and pressure.

Numeral 10 denotes a paper discharging means, which is a face-up tray 10a for discharging the paper thermally fixed by the fixing means 9 with the printing surface up and a face-down tray 10b for discharging the paper with the printing surface down. Is arranged.

FIG. 2 is a diagram for explaining the control configuration of the present invention.
An outline of the operation will be described. Image processing controller 10
1, a print request is requested through serial communication. At this time, since the image processing controller 101 knows the content of the image to be printed, the image forming mode is also transmitted through the serial communication at substantially the same timing as the print request.

When a print request is received, the engine control CPU 1
In step 04, motors such as a scanner motor and a main motor are started to prepare for printing. Laser scanner unit 10
When the scanner motor in 5 rotates, the scanning direction signal becomes P
Output from the D sensor 106. When the main motor rotates, the timing signal in the sub-scanning direction is
7 is output.

The engine CPU 104 confirms that the scanner motor, the main motor and the like have reached the rated rotation speed, and permits the operation of the timing control unit 103.

The timing control unit 103 includes an engine CPU
By permitting the operation of 104, the image writing timing signal VSYNC is output from the OD signal, and the scanning direction timing signal LSYNC is output from the PD signal. The laser scanner unit 105 is not involved in permitting the operation of the engine CPU 104.
And outputs a signal LONB for controlling the laser power. The engine CPU 104 monitors the OD signal,
The page selection signal PSEL is switched according to the flag.

The image processing controller uses the image writing timing signal VSYNC, the scanning direction timing signal LSYNC, and the page selection signal PSEL to perform primary (first image forming on the intermediate transfer member) or secondary (second image forming on the intermediate transfer member). The image data of the (sheet) is selected and output to the VDO. The video control unit 102 is the image processing controller 10
A signal LONB for controlling the laser power of the laser scanner unit 105 is synthesized with the video signal VDO from 1 and output to the laser scanner unit 105.

When the engine CPU 104 does not permit the operation of the timing control unit 103, the timing control unit 1
From 03, the image writing timing signal VSYNC and the scanning direction timing signal LSYNC are not output.

FIG. 3 is a diagram for explaining the basic timing of printing a plurality of pages according to the present invention, and illustrates the case of full-color printing and the case of monochrome black printing.

When a full-color print request is issued from the image processing controller 101 through serial communication, the first full-color image is formed as a primary image. The intermediate transfer member has no specific positional relationship between primary and secondary, and the first image forming position after a discontinuous print request is made primary.

After a delay of two rotations of the intermediate transfer member, when there is a next print request through serial communication until the secondary print start reference is reached, an image is formed on the secondary. The number of delays is not fixed and may be a delay of 1 to 3 rotations.

An image is formed on the primary when there is a next print request through serial communication until the next primary printing start reference is reached. In this case, no image is formed on the primary because there is no request.

When there is a next print request through serial communication until the next print start reference after the secondary image formation is completed, the image is initialized once and an image is formed on the primary. In this case, since the image is monochrome black, the image is initialized and an image is formed on the primary.

FIG. 4 is a diagram for explaining the timing of printing a plurality of pages when a print request is delayed according to the present invention. When a full-color printing request is issued from the image processing controller 101 through serial communication, the first full-color image is formed as a primary image.

If there is a next print request through serial communication after the delay of two rotations of the intermediate transfer member and before the secondary print start reference is formed, an image is formed on the secondary side. Does not form an image.

When there is a next print request through serial communication after the completion of the primary image formation and before the next print start reference, it is initialized once and an image is formed on the primary.

After a delay of two rotations of the intermediate transfer member and before a secondary print start reference is made, an image is formed on the secondary when there is a next print request through serial communication.

FIG. 5 is a diagram for explaining the timing of printing a plurality of pages in a mixture of monochrome and full color according to the present invention. When a full-color printing request is issued from the image processing controller 101 through serial communication, the first full-color image is formed as a primary image.

After a delay of two rotations of the intermediate transfer member and before the secondary printing start reference is reached, if there is a next printing request through serial communication, an image is formed on the secondary side. Does not form an image.

When there is a next print request through serial communication after the completion of the primary image formation and before the next print start reference, it is initialized once and an image is formed on the primary. In this case, since the printing is monochrome black printing, the image is initialized and an image is formed on the primary.

Although not shown in FIGS. 3 to 5, the control is performed so that the printing operation is performed in four rotations, which is the same as full color, except for monochrome magenta or the like other than black. Therefore, a plurality of pages are controlled in the same cycle as the full-color printing. It should be noted that a color other than black, such as monochromatic magenta, can be selected through serial communication or the like so that the printing process can be performed in one rotation in the same manner as monochromatic black. In the case of forming an image in one rotation as in the case of monochrome black, print control can be performed only by the primary, so that there is no need for secondary processing.

FIG. 6 is a flowchart 1 illustrating the printing sequence. When there is a print request, motor operation control and the like for a printing process (not shown) are performed and the OD signal is monitored (step 1).

When the OD signal is detected, it is checked whether or not printing of a plurality of pages is possible, and then printing control is performed. First, it is determined whether there is a print request (step 2). If there is no print request, the process skips to print control. When there is a print request, the print mode is checked (step 3), and a print mode other than full color, monochrome black, and monochrome black is determined. If the print mode is not full color, monochrome black, the current print state is determined by a flag (step 4).

If the primary and secondary print flags are cleared, the timing and cycle flags are initialized (step 5), the primary print flag is set (step 6), and the print request flag is cleared (step 6). Step 7) Perform print control.

If the print flag is set for both the primary and the secondary, the printing is skipped because a plurality of pages cannot be printed.

If the print flag is set to primary set or secondary cleared, it is compared with the print cycle of the currently printed page (step 8). If it is the same cycle, it is determined whether or not it is the secondary image forming reference (step 9),
If not, skip. If it is the secondary image forming reference, the secondary print flag is set (step 1).
0), the print request flag is cleared (step 11), and print control is performed.

If the print flag is set to primary clear or secondary, the print cycle is compared with the print cycle of the currently printed page (step 12). If it is the same cycle, it is determined whether or not it is the primary image forming reference (step 1).
3) If not, skip. If it is the primary image forming reference, the primary print flag is set (step 14), and the print request flag is cleared (step 1).
5) Perform print control.

Returning to the processing, if the print request is monochrome black (Yes in step 16), the printing state is determined by a flag (step 17). If the print flag is set to primary, printing is not possible and skipping is performed. If the print flag is primary cleared, the timing and cycle flag are initialized (step 18), and then the primary print flag is set (step 1).
9) The print request flag is cleared (step 20), and print control is performed.

FIG. 7 is a flowchart 2 illustrating the printing sequence. In the printing control, first, the cycle flag is checked (step 21), and it is determined whether the printing is primary or secondary.

The primary processing is as follows. Check the primary print flag (step 2
2) If the flag is cleared, the timing control unit is disabled (step 23) and skipped. If the flag is set, the page selection signal PSEL is set to primary "H" (step 24), the operation of the timing control unit is permitted (step 25), and the developing device is selected and switched to the developing color (step 24). 26), an image writing timing signal VSYNC from the timing control unit 103,
The scanning direction timing signal LSYNC is output from the engine CPU 10
4 outputs a page selection signal PSEL, and the image processing controller 101 outputs image data. This is developed and transferred to form an image on the intermediate transfer member (step 2).
7).

The processing for monochrome black is included in the primary printing processing, and is different only in the printing cycle.

It is determined whether printing of all pages has been completed (step 30). If not completed, the process returns to the process. If completed, the printing sequence is exited.

Next, the secondary processing is as follows. The secondary print flag is checked (step 31), and if the flag is cleared, the timing control section is disallowed (step 32) and skipped. If the flag is set, the page selection signal PSEL is set to the secondary "L" (step 33), the number of rotation delays is checked (step 34), and if the number is not the set number, skip. If the set number has been reached, the operation of the timing control unit is permitted (step 35), the developing unit is selected and switched to the color to be developed (step 36), and the timing control unit 103 outputs the image writing timing signal VS.
YNC, scanning direction timing signal LSYNC
A page selection signal PSEL is output from 104, and image data is output from the image processing controller 101. This is developed and transferred to form an image on the intermediate transfer member (Step 3).
7).

It is determined whether printing of all pages has been completed (step 30). If not completed, the process returns to the process. If completed, the print sequence is exited.

According to the present invention, as described above,
When the toner image for one sheet is a specific single color, the image is continuously formed on the intermediate transfer member. When the toner images for two sheets on the intermediate transfer member are other than the specific single color or two or more colors, the intermediate image is formed. It is characterized in that an image is formed on the transfer body at a timing different from the predetermined number of rotations. As a result, even if monochrome and full-color printing are mixed, print control without page overtaking is possible, and a color image forming apparatus with high throughput can be provided. In this embodiment, the case where the intermediate transfer body has a circumferential length capable of forming two sheets of images in A4 horizontal size conveyance has been described. It suffices if there is more than three sheets. Further, in this embodiment, the case where black is used as the specific single color has been described. However, another single color (yellow, cyan, magenta) may be used, and the specific single color may be arbitrarily selected by the user.

[0050]

As described above, the color image forming apparatus of the present invention has the following effects. (1) It is possible to provide a color image forming apparatus which has high throughput even in a case where printing control is performed in consideration of an image processing time and both monochrome and full-color printing are mixed. (2) It is possible to perform print control in consideration of the image processing time and without overtaking pages even when a specific monochrome and full color image are mixed. (3) A specific single-color image can be printed at a high speed, and other single-color images can take a long time to form an image, thereby improving color development and giving a margin to the stirring capacity of the developing device.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating a color image forming apparatus of the present invention.

FIG. 2 is a diagram illustrating a control configuration of the present invention.

FIG. 3 is a diagram for explaining the basic timing of printing a plurality of pages according to the present invention.

FIG. 4 is a diagram illustrating a timing of printing a plurality of pages when a print request according to the present invention is delayed.

FIG. 5 is a diagram illustrating the timing of printing a plurality of pages in a mixture of monochrome and full color according to the present invention.

FIG. 6 is a flowchart 1 illustrating a printing sequence.

FIG. 7 is a flowchart 2 illustrating a print sequence.

[Explanation of symbols]

 1: color image forming apparatus main body 2: photosensitive drum 3: charging roller 4: exposure unit 5: developing unit 31: cleaning unit 6: intermediate transfer drum 6a: secondary transfer roller 6b: cleaning roller 7: paper supply unit 8: Conveying belt 9: fixing means 10: paper discharging means

Claims (6)

[Claims] 1. A method of forming toner images of different colors sequentially on one or a plurality of photoconductors, sequentially transferring the toner images to an intermediate transfer member, and superimposing the images on the intermediate transfer member to form an image. In a color image forming apparatus that collectively transfers a toner image on an intermediate transfer member to a recording material, a peripheral length capable of holding a plurality of toner images of the intermediate transfer member on a predetermined recording material is determined. When a plurality of toner images on the intermediate transfer body have a specific single color, a toner image to be formed on the photoconductor is continuously formed and transferred to the intermediate transfer body to form an image. When the toner images of a plurality of sheets formed on the intermediate transfer body are other than a specific single color or two or more colors, the toner images of the same color formed on the photoconductor are different from each other by a predetermined rotation speed of the intermediate transfer body. Formed at the same timing as the transfer on the intermediate transfer body. Color image forming apparatus, characterized by image forming. 2. A color image according to claim 1, wherein when forming a plurality of toner images on the intermediate transfer member, the image forming cycle of the plurality of toner images is the same. Forming equipment. 3. The color image forming apparatus according to claim 1, wherein said specific single color can be selected. 4. The method according to claim 1, wherein a color other than a specific single color or 2
In the case of forming a plurality of toner images of a plurality of colors or more, the image forming apparatus further includes a plurality of image formation determining means for determining whether a plurality of toner images can be formed on the intermediate transfer body. When it is determined that a plurality of toner images can be formed on the intermediate transfer member, a plurality of toner images are formed on the intermediate transfer member, and it is determined that the plurality of toner images cannot be formed. 4. A color image forming apparatus according to claim 1, wherein the image forming means forms an image of the next toner image at a position where the image forming of the intermediate transfer member is possible after the image forming of the preceding toner image is completed. apparatus. 5. A plurality of image formation start reference determining means for determining each image formation start reference in a plurality of toner images, and a toner image formation on the intermediate transfer member. An image forming condition judging unit for judging a state, and an image forming condition judging unit for judging whether an image forming condition of a new toner image is satisfied, and wherein the image forming condition judging unit determines an image forming state on the intermediate transfer body. And if the image forming condition determining means satisfies the image forming condition of the next toner image with the image forming start criterion determined by the image forming start criterion determining means of the next toner image, 5. The color image forming apparatus according to claim 1, wherein it is determined that a plurality of toner images can be formed thereon. 6. In a case where toner images having different cycles are successively formed on the intermediate transfer body, the toner image may be formed on the intermediate transfer body at a position where image formation on the intermediate transfer body is possible immediately after completion of image formation of a preceding toner image. 2. The color image forming apparatus according to claim 1, wherein the next toner image is formed.