JPH08314232A - Multicolor image forming apparatus and image writing method for multicolor image forming apparatus - Google Patents

Abstract

(57) [Summary] [Purpose] Throughput can be greatly increased by transferring multiple images from a position where they do not interfere with each other, and from a position where image breakage does not occur, and transfer them continuously to a recording medium. Can be improved. A constitution is characterized in that the CPU 2 determines a writing timing for writing a multicolor image on the photoconductor in synchronization with a predetermined detection output sequentially output from the sensor 212.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic multicolor image forming apparatus having an intermediate transfer member, and more particularly to a multicolor image forming apparatus and a multicolor image forming apparatus capable of forming images for a plurality of pages on the intermediate transfer member. The present invention relates to an image writing method of a color image forming apparatus.

[0002]

2. Description of the Related Art FIG. 11 is a schematic sectional view for explaining the structure of a conventional electrophotographic multicolor image forming apparatus.

When a switch (not shown) of the multi-color image forming apparatus 101 is turned on, a rising sequence is performed, and then a sub-scanning synchronization signal flag on the intermediate transfer member 107 at the position of point A (home position) in FIG. 110 Stop the tip.

When a print request occurs, the intermediate transfer member 1
Reference numeral 07 rotates in the direction of the arrow in the figure, and a sub-scanning synchronization signal is generated when the sub-scanning synchronization signal flag 110, which was at the home position when stopped, passes through the sensor 112.
The scanner unit 104 generates a laser ON / OFF signal based on image data sent from a controller (not shown) in synchronization with the sub-scanning synchronization signal, scans the laser light on the photosensitive drum 105, and forms a latent image. To form.

Then, the formed latent image is developed by the first color developing device of the rotary developing device unit 106, and the developed image is transferred to the intermediate transfer member 107. When the transfer of the first color is completed, the rotary developing device is switched to the next developing device. Similarly, when the sub-scanning synchronization signal flag 110 passes through the sensor 112, the latent image, the development, and the transfer are repeated in synchronization with each other, and when the transfer of the fourth color is completed, the sheet feeding cassette 102 is set at a predetermined timing. Alternatively, the sheet is fed from the multi-feed tray 103, and the transfer roller 113 is brought into contact with the intermediate transfer body 107 to perform secondary transfer on the sheet. The transferred sheet is fixed by the fixing device 108 and discharged to the discharge tray 109.

[0006]

However, in the above-mentioned conventional example, there is a problem that a series of sequences must be performed in accordance with the maximum usable paper.

Further, when the image data for a plurality of pages is written, there is a problem that the image can be guaranteed only for the first image.

The present invention has been made to solve the above problems, and an object of the first to fifth inventions according to the present invention is to provide a predetermined or arbitrary sub-image on a moving intermediate transfer member. By detecting the synchronization member that indicates the position in the scanning direction and determining the image writing timing, multiple images can be transferred continuously from a position where the images do not interfere with each other and no image breakage occurs. It is an object of the present invention to provide a multicolor image forming apparatus and an image writing method for the multicolor image forming apparatus, which can significantly improve the throughput by transferring to a recording medium.

[0009]

According to a first aspect of the present invention, a multicolor transfer image obtained by transferring each color image onto an endlessly moving intermediate transfer member is transferred onto a fed recording medium. In a multicolor image forming apparatus that forms an image, a plurality of synchronization members that indicate predetermined sub-scanning direction positions according to the movement of the intermediate transfer member, a detection unit that detects each of the synchronization members at a predetermined position, and the detection And a determining unit that determines a writing timing for writing a multicolor image on the photoconductor in synchronization with a predetermined detection output sequentially output from the unit.

A second aspect of the present invention is a multicolor image forming apparatus in which an image is formed by transferring a multicolor transfer image obtained by transferring an image of each color onto an endlessly moving intermediate transfer member to a fed recording medium. In the image forming apparatus, a plurality of synchronization members indicating arbitrary positions in the sub-scanning direction according to the movement of the intermediate transfer member, a detection unit that detects each of the synchronization members at predetermined positions, and the detection unit sequentially outputs. And a deciding means for deciding a writing timing for writing a multicolor image on the photoconductor in synchronization with any of the detection outputs.

According to a third aspect of the present invention, the intermediate transfer member comprises an intermediate transfer member drum.

A fourth aspect of the present invention is provided with a plurality of synchronizing members that show a predetermined position in the sub-scanning direction according to the movement of the endlessly moving intermediate transfer member, and transfers each color image onto the intermediate transfer member. In the image writing method of the multicolor image forming apparatus, in which the multicolor transfer image obtained by the above is transferred to a fed recording medium to form an image, a detection step of detecting each of the synchronizing members at a predetermined position and a sequential output are performed. And a determination step of determining a writing timing for writing a multicolor image on the photoconductor in synchronization with a predetermined detection output.

A fifth aspect of the present invention is provided with a plurality of synchronizing members which show a predetermined position in the sub-scanning direction according to the movement of the endlessly moving intermediate transfer member, and transfers each color image onto the intermediate transfer member. In the image writing method of the multicolor image forming apparatus, in which the multicolor transfer image obtained by the above is transferred to a fed recording medium to form an image, a detection step of detecting each of the synchronizing members at a predetermined position and a sequential output are performed. And a determination step of determining a writing timing for writing a multicolor image on the photoconductor in synchronization with any one of the detection outputs.

[0014]

In the first aspect of the invention, the determining means determines the writing timing for writing the multicolor image on the photosensitive member in synchronization with the predetermined detection output sequentially output from the detecting means,
This makes it possible to transfer a plurality of images from a predetermined position on the intermediate transfer member without interfering with each other and causing no image loss.

In the second aspect of the present invention, the determining means determines the writing timing for writing the multicolor image on the photosensitive member in synchronization with any of the detection outputs sequentially output from the detecting means, and determines the writing timing on the intermediate transfer member. In addition, it is possible to transfer a plurality of images from an arbitrary position where the images do not interfere with each other and do not cause image loss.

According to the third aspect of the invention, it is possible to transfer a plurality of images from a predetermined position on the intermediate transfer drum without interfering with each other and causing no image loss. .

In the fourth invention, each synchronizing member is detected at a predetermined position, and a writing timing for writing a multicolor image on the photosensitive member is determined in synchronization with a predetermined detection output which is sequentially output, and the intermediate timing is determined. It is possible to automate the process of transferring a plurality of images from a predetermined position at which a plurality of images do not interfere with each other on the transfer body and no image loss occurs.

In the fifth aspect of the invention, each synchronizing member is detected at a predetermined position, and the writing timing for writing the multicolor image on the photosensitive member is determined in synchronization with one of the detection outputs that are sequentially output, It is possible to automate the process of transferring the images of a plurality of sheets from an arbitrary position that does not cause image loss without the images of a plurality of sheets interfering with each other on the intermediate transfer body.

[0019]

EXAMPLES Examples of the present invention will be described in detail below.

[First Embodiment] FIG. 1 is a schematic sectional view for explaining the structure of a multicolor image forming apparatus showing a first embodiment of the present invention.

In the figure, 201 is a housing of the engine of the multicolor image forming apparatus, 202 is a paper feed cassette, and 203 is a multi paper feed tray for manually feeding paper. Two
A scanner unit 04 scans the photosensitive drum 205 with laser light by a laser ON / OFF signal generated based on image data sent from a controller (not shown). In addition, 1 is an image controller, which comprises a CPU 2, a RAM 4, and a ROM 3,
The image sequence is comprehensively controlled based on the control program stored in.

Reference numeral 206 denotes a rotary developing unit, which contains cartridges containing magenta (M), cyan (C), yellow (Y), and black (Bk) developers, respectively. Here, the four-color developing cartridges are housed in the rotary developing unit, but the structures of the developing cartridges housed in the rotary developing unit are Y, M, and C.
The black developing device may be a fixed type with only the color developing cartridge of.

Reference numeral 207 denotes an intermediate transfer member, which is the photosensitive drum 2
The developed image developed on 05 is transferred (primary transfer), and this is repeated four times, and then the transfer roller 213 is brought into contact with the intermediate transfer member 207 to be transferred (secondary transfer) onto a sheet.

Reference numeral 208 denotes a fixing device for fixing the developer secondarily transferred onto the paper to the paper. 209
Is a discharge tray for stocking the fixed paper. Reference numerals 210 and 211 denote sub-scanning cycle flags for sub-scanning synchronization signals, and these flags are used for the intermediate transfer member 20.
It is arranged at a position rotated by 180 degrees with respect to the center of 7. The tip of the sub-scanning synchronization flags 210 and 211 is the sensor 2
Sub-scanning synchronization signals are generated by passing through 12.

Next, with reference to FIGS. 2, 3, 4, and 5, regarding a series of sequences in which images for a plurality of pages are written in the intermediate transfer member 207 in the multicolor image forming apparatus according to the present invention. explain.

FIG. 4 is a principal block diagram for explaining the control configuration of the multicolor image forming apparatus according to the present invention. The same parts as those in FIGS. 2 and 3 are designated by the same reference numerals.

When a power source (not shown) of the image forming apparatus is turned on, the CPU 801 of the engine of the image forming apparatus performs a series of start-up sequences, and the leading end of any one of the sub-scanning synchronization signal flags attached to the intermediate transfer member 207 is detected. At the home position A of FIG. 2B (the leading end of the sub-scanning synchronization signal flag 210 in the figure), the intermediate transfer member 207 is reached.
To stop. The print sequence will be described below with reference to the flowchart shown in FIG.

FIG. 5 is a flow chart for explaining the print sequence of the multicolor image forming apparatus according to the present invention. Note that (1) to (11) indicate each step.

Upon receiving the print request, the image forming apparatus starts the print sequence and rotates the intermediate transfer member 207 in the direction of the arrow in the figure. CPU 801 is intermediate transfer member 2
With the rotation of 07, in step (1), the permission signal / TOPENB for permitting the input of the sub-scanning synchronization signal is turned on before the sub-scanning synchronization signal flag 210 reaches the sensor 212,
Output to the sub-scanning control circuit 802. Here, the permission signal / TOPENB is output by controlling the movement time from the home position by the CPU 801, and is turned off after a certain time has elapsed after the sub-scanning synchronization signal was input.

In step (1), the / TOPENB signal is O
Then, in step (2), the sub-scanning control circuit 802 waits for the input of the sub-scanning synchronization signal, and when the sub-scanning synchronization flag 210 passes through the sensor 212, as shown in FIG. In step (3), the sub-scanning control circuits 802 to 1
When the sub-scanning synchronization signal V1 of the page is generated and the sub-scanning synchronization signal V1 is generated, the image controller 1 laser-controls the image signal / VDO in synchronization with the sub-scanning synchronization signal V1 in step (4). Output to the circuit 803.

At this time, the laser control circuit 803 validates the image signal / VDO sent from the image controller 1 only in the non-masked area of the sub-scanning mask signal TOPE controlled by the CPU 801 in step (4), A laser ON / OFF signal based on the image signal / VDO is generated in the valid area, and the laser ON / OFF signal is sent to the scanner unit 204. In the scanner unit 204, the laser ON / OFF signal sent from the laser control circuit 803 is sent. Laser light is modulated by the OFF signal to perform scanning / latent image formation on the photosensitive drum 205.

The latent image is the first image of the rotary developing unit 206.
The image is developed by the developing device of the color and the developed image is the intermediate transfer member 2.
It is transferred to 07.

Next, in step (5), it is judged whether or not the print mode is the two-page mode, and when it is in the two-page mode, the processing is continued to step (6), and the sub-scanning synchronizing signal input for the first page is started. At a predetermined time managed by the CPU 801, a permission signal / TOPENB for permitting the input of the sub-scanning synchronization signal of the second page is turned on before the sub-scanning synchronization signal flag 211 reaches the sensor 212.
And outputs it to the sub-scanning control circuit 802. Here, the permission signal / TOPENB is turned off after a certain period of time has elapsed since the sub-scanning synchronization signal was input.

In step (6), the permission signal / TOPENB
When is turned on, in step (7), the sub-scanning control circuit 8
02 waits for the input of the sub-scanning synchronization signal, and
As shown in (b), the sub-scanning synchronization flag 211 indicates that the sensor 2
When passing through 12, the sub-scanning control circuit 802 generates the sub-scanning synchronization signal V2 for the second page in step (8).

When the sub-scanning synchronizing signal V2 is generated as in the case of the first page, in step (9), the image controller 1 synchronizes with the sub-scanning synchronizing signal V2 and the image signal of the second page / The VDO is output to the laser control circuit 803. At this time, the laser control circuit 803 validates the image signal / VDO sent from the image controller 1 only in the non-masked area of the sub-scanning mask signal TOPE controlled by the CPU 801 in step (9),
When the image is in the effective area, a laser ON / OFF signal is generated based on the image signal / VDO, the laser ON / OFF signal is sent to the scanner unit 204, and the scanner unit 2
In 04, laser light is emitted from the photosensitive drum 205 by the laser ON / OFF signal sent from the laser control circuit 803.
Perform scanning and latent image formation on top.

The latent image is developed by the first color developing device of the rotary developing device unit 206, and the developed image is transferred to the intermediate transfer member 207. When the transfer of the first color of the second page of step (9) is completed, the rotary developing device unit 206 is rotated by 90 degrees in the direction of the arrow in the figure in step (10), and the fourth color of step is transferred in step (11). It is determined whether or not the transfer is completed, and when the fourth color is not completed, the process returns to step (1) and the first page is read at a predetermined time controlled by the CPU 801 from the input of the sub-scanning synchronization signal for the second page. / TOP that allows input of sub-scanning sync signal
The ENB is turned on before the sub-scanning synchronization signal flag 210 reaches the sensor 212, and is output to the sub-scanning control circuit 802. Thereafter, steps (1) to (11) are repeated, and the developed images of the second, third, and fourth colors are transferred onto the transferred image of the first color. Then, when the developed images of four colors are formed on the intermediate transfer body, it is determined in step (11) that the transfer of the fourth color is completed, and the processing for forming the transferred image on the intermediate transfer body 207 is completed. Then, the process shifts to the transfer (secondary transfer) sequence to the sheet.

Paper is fed from the paper feed cassette 202 or the multi-paper feed tray 203 at a predetermined timing, and the secondary transfer is performed from the intermediate transfer body 207 to the paper at the transfer roller 213. The sheet that has been secondarily transferred is the fixing device 2.
The sheet is fixed at 08 and discharged to the sheet discharge tray 209. After the secondary transfer of two pages is completed, the intermediate transfer body 207 is stopped at the home position as shown in FIG.

Further, when printing only one page of image from the stopped state of FIG. 2A, after the transfer of the first color is completed, the process is jumped from step (5) to step (10). In step (10), the rotary developing device unit 206 is rotated 90 degrees in the direction of the arrow in the figure. Fourth
When the transfer of the color is not completed, step (11)
To step (1), the signal / T which permits the input of the sub-scanning synchronization signal of the second color at a predetermined time controlled by the CPU 801 from the input of the sub-scanning synchronization signal of the first color.
OPENB indicates that the sub-scanning synchronization signal flag 210 is the sensor 21.
It turns on before reaching 2, and outputs it to the sub-scanning control circuit 802. Thereafter, the same process is repeated, the developed images of the second, third, and fourth colors are transferred onto the transferred image of the first color, and the developers of four colors are formed on the intermediate transfer body 207. If so, it is determined in step (11) that the transfer of the fourth color has been completed, the processing for forming a transfer image on the intermediate transfer member 207 is completed, and the sequence for transferring to the paper (secondary transfer) is started. The process is transferred to the paper feed cassette 202 or
Paper is fed from the multi-paper feed tray 203 at a predetermined timing, and the intermediate transfer body 207 is placed at the transfer roller 213.
Secondary transfer is performed on the paper.

The sheet that has been secondarily transferred is fixed by the fixing device 208, and is discharged to the discharge tray 209.
When the secondary transfer is finished, another sub-scanning synchronization flag 211
When the home position is reached, the intermediate transfer body 207 can be stopped and the processing can be ended.

Correspondence between this embodiment and each means of the first and third inventions and their operation will be described below with reference to FIG.

The first invention according to the present invention is a multicolor image forming method in which a multicolor transfer image obtained by transferring an image of each color onto an endlessly moving intermediate transfer member is transferred to a fed recording medium to form an image. In the image forming apparatus, a plurality of synchronization members (synchronization signal flags 210) indicating predetermined positions in the sub-scanning direction according to the movement of the intermediate transfer member, and detection means (sensor 212) for detecting each of the synchronization members at predetermined positions. And a determination unit (by the CPU 2 of the image controller 1) that determines a writing timing for writing a multicolor image on the photoconductor in synchronization with a predetermined detection output sequentially output from the detection unit. The CPU 2 determines the write timing for writing the multicolor image on the photoconductor in synchronization with a predetermined detection output sequentially output from, and a plurality of images interfere with each other on the intermediate transfer body. And without and makes it possible to transfer an image of a plurality of sheets from the predetermined position causing no image loss.

According to a third aspect of the present invention, the intermediate transfer member is composed of an intermediate transfer member drum, and images on a plurality of sheets do not interfere with each other on the intermediate transfer drum and no image loss occurs. It is possible to transfer a plurality of images from a predetermined position.

Correspondence between the present embodiment and each step of the fourth invention and its action will be described below with reference to FIG.

A fourth invention according to the present invention is provided with a plurality of synchronizing members which show a predetermined position in the sub-scanning direction according to the movement of the endlessly moving intermediate transfer member, and transfers each color image onto the intermediate transfer member. In the image writing method of the multicolor image forming apparatus, in which the multicolor transfer image obtained by the above is transferred to a fed recording medium to form an image, a detection step of detecting each of the synchronizing members at a predetermined position and a sequential output are performed. The CPU 2 of the image controller 1 performs the R determination process of determining the write timing for writing the multicolor image on the photoconductor in synchronization with the predetermined detection output.
Processing that is executed based on a control program stored in the OM3 and that transfers a plurality of images from a predetermined position on the intermediate transfer body without interfering with each other and causing no image loss. It is possible to automate.

[Second Embodiment] FIG. 6 is a schematic sectional view for explaining the structure of a multicolor image forming apparatus showing a second embodiment of the present invention.

In FIG. 6, reference numeral 401 is a housing of the engine of the multicolor image forming apparatus, 402 is a paper feed cassette, and 403.
Is a multi paper feed tray for manually feeding paper.

A scanner unit 404 scans the photosensitive drum 405 with laser light by a laser ON / OFF signal generated based on image data sent from a controller (not shown). Reference numeral 406 denotes a rotary developing unit, which contains cartridges containing magenta (M), cyan (C), yellow (Y), and black (Bk) developers, respectively. Here, 4
The color developing cartridge is housed in the rotary developing unit, but the developing cartridge housed in the rotary developing unit has only Y, M, and C color developing cartridges, and the black developing unit is a fixed type. But it doesn't matter.

Reference numeral 407 denotes an intermediate transfer member, which is the photosensitive drum 4
The developed image developed on 05 is transferred (primary transfer), and this is repeated four times, and then the transfer roller 413 is brought into contact with the intermediate transfer member 407 to be transferred (secondary transfer) to a sheet.
A fixing device 408 is for fixing the developer secondarily transferred onto the paper to the paper.

A paper discharge tray 409 is used for stocking the fixed paper. Reference numeral 410 is a sub-scanning synchronization signal flag, which is flag A (FA) in this embodiment.
12 flags from FA to F (F) are FA and F
G, FB and FH, FC and FI, FD and FJ, FE and F
The positions of K, FF, and FL are respectively rotated by 180 degrees when viewed from the center of the intermediate transfer member 407, but may be present at arbitrary positions. When passing through the sensor 412, a sub-scanning synchronization signal is generated.

Next, with reference to FIGS. 7, 8, 9, and 10, a series of sequences when images for a plurality of pages in the multicolor image forming apparatus according to the present invention are written in the intermediate transfer member 407. Will be described.

7 and 8 are views for explaining a multi-page image sequence in the multicolor image forming apparatus according to the present invention, and the same elements as those in FIG. 6 are designated by the same reference numerals.

FIG. 9 is a block diagram of another main part for explaining the control configuration of the multicolor image forming apparatus according to the present invention. The same parts as those in FIG. 6 are designated by the same reference numerals.

When the power source (not shown) of the image forming apparatus is turned on, the CPU 1001 of the image forming apparatus engine performs a series of start-up sequences to stop the intermediate transfer member 407 at an arbitrary position (see FIG. 7A). . The print sequence will be described below based on the flowchart shown in FIG.

FIG. 10 is a flow chart for explaining another print sequence of the multicolor image forming apparatus according to the present invention. Note that (1) to (11) indicate each step.

When a print request is issued, the image forming apparatus starts the print sequence and rotates the intermediate transfer member 407 in the direction of the arrow in the figure. With the rotation of the intermediate transfer member 407, the CPU 1001 inputs the sub-scanning synchronization signal in step (1) after a certain time elapses with reference to the sub-scanning synchronization signal flag (flag FA in the figure) that first passes through the sensor 412. Is turned on before the sub-scanning synchronization signal flag FB reaches the sensor 412,
Output to the sub-scanning control circuit 1002.

The permission signal / TOPENB does not exceed the fixed time after the sub-scanning synchronizing signal is input (the time until the next sub-scanning synchronizing signal flag (flag FC in the figure) passes through the sensor 412). It is turned off after a lapse of time.

In step (1), a permission signal / TOPENB
When is turned on, in step (2), the sub-scanning control circuit 1
002 waits for the input of the sub-scanning synchronization signal, and when the sub-scanning synchronization flag FB passes the sensor 412 as shown in FIG. 7B, the sub-scanning control circuit 1002 outputs the sub-page of the first page in step (3). The scan synchronization signal V1 is generated.

In this embodiment, since the home position does not exist and the time when the first flag passes the sensor 412 differs depending on the case, the sub-scanning synchronizing signal is generated by the second flag that passes. However, if there is no problem in the sequence, the sub-scanning synchronization signal may be generated by the flag that passes first.

When the sub-scanning synchronization signal V1 is generated in step (3), the image controller 1 is operated in step (4).
Then, the image signal / VDO is output to the laser control circuit 1003 in synchronization with the sub-scanning synchronization signal V1.

Further, in step (4), the laser control circuit 1003 validates the image signal / VDO sent from the image controller 1 only in the non-masked area of the sub-scanning mask signal TOPE controlled by the CPU 1001, and in the image valid area. Sometimes laser ON based on image signal / VDO
/ OFF signal is generated and the laser ON / OFF signal is sent to the scanner unit 404. Scanner unit 404
Then, a laser beam is scanned and a latent image is formed on the photosensitive drum 405 by a laser ON / OFF signal sent from the laser control circuit 1003. The latent image is developed by the first color developing device of the rotary developing device unit 406, and the developed image is transferred to the intermediate transfer member 407.

In step (5), the print mode is set to 2
It is determined whether or not the page mode is set, and when it is the 2-page mode, the process proceeds to step (6). Here, when the area for one page is from the front end of the flag FB to the front end of the flag FF according to the paper size information sent from the image controller 1, the time when the front end of the flag FF passes the sensor 412 is used as a reference. In addition, the signal / TOPENB for permitting the input of the sub-scanning synchronization signal of the second page at a predetermined time managed by the CPU 1001 is set to the flag FG.
Is turned on before reaching the sensor 412, and is output to the sub-scanning control circuit 1002. Where permission signal / TOPEN
B indicates that the sensor 41 has a predetermined time (the next sub-scanning synchronization signal flag (flag FH in the drawing)) after the sub-scanning synchronization signal is input.
It does not exceed the time to pass 2) O after the passage
FF is done.

In step (6), a permission signal / TOPENB
When is turned on, in step (7) the sub-scanning control circuit 10
Reference numeral 02 waits for the input of the sub-scanning synchronization signal, and when the flag FG passes the sensor 412, the sub-scanning control circuit 1002 generates the sub-scanning synchronization signal V2 of the second page in step (8). As with the first page, step (8)
When the sub-scanning synchronization signal V2 is generated at step (9)
Then, in the image controller 1, the image signal / VDO of the second page is supplied to the laser control circuit 1 in synchronization with the sub-scanning synchronization signal V2.
Output to 003.

In step (9), the laser control circuit 1003 validates the image signal / VDO sent from the image controller 1 only in the non-masked region of the sub-scanning mask signal TOPE controlled by the CPU 1001, and the image valid region Sometimes laser O based on image signal / VDO
An N / OFF signal is generated and a laser ON / OFF signal is sent to the scanner unit 404.

The scanner unit 404 scans the laser beam on the photosensitive drum 405 and forms a latent image by the laser ON / OFF signal sent from the laser control circuit 1003. The latent image is developed by the first color developing device of the rotary developing device unit 406, and the developed image is transferred to the intermediate transfer member 407.
Is transferred to When the transfer of the first color of the second page in step (9) is completed, the rotary developing device unit 406 is rotated 90 degrees in the direction of the arrow in the figure in step (1), and the transfer of the fourth color in step (11). Is finished, and if the fourth color is not finished, step (1)
Returning to C, C is based on the leading edge of the flag A, which is immediately before the flag FB that is the sub-scanning synchronization signal of the first color of the first page.
A permission signal / TO that permits the input of the sub-scanning synchronization signal of the first page at a predetermined time managed by the PU 1001.
The PENB is turned off before the flag FB reaches the sensor 412.
N, and output to the sub-scanning control circuit 1002. Thereafter, steps (1) to (11) are repeated, and the developed images of the second, third, and fourth colors are transferred onto the transferred image of the first color.

The developing agents for the four colors are used as the intermediate transfer member 40.
When it is formed on the image transfer sheet 7, it is determined in step (11) that the transfer of the fourth color is completed, the processing for forming the transfer image on the intermediate transfer member 407 is completed, and the transfer (secondary transfer) to the sheet is performed. ) The process is transferred to the sequence.

Paper is fed from the paper feeding cassette 402 or the multi-paper feeding tray 403 at a predetermined timing, and the paper is fed from the intermediate transfer member 407 to the paper at the transfer roller 413.
Next transfer is performed. The sheet that has been secondarily transferred is the fixing device 408.
Then, the sheet is fixed on the sheet, and the sheet is discharged to the sheet discharge tray 409. The intermediate transfer member 407 is stopped when the front end of the flag FJ passing through the sensor 412 is detected after completing the secondary transfer for two pages.

Correspondence between the present embodiment and each means of the second invention and its operation will be described below with reference to FIG.

The second invention is an intermediate transfer member 4 which moves endlessly.
In the multi-color image forming apparatus for transferring the multi-color transfer image obtained by transferring each color image onto the recording medium to be fed to form an image, an arbitrary sub-image is transferred according to the movement of the intermediate transfer member 407. A plurality of synchronization members (synchronization signal flags FA to FF) indicating the position in the scanning direction, detection means (sensor 412) for detecting each of the synchronization members at a predetermined position, and any one of detection outputs sequentially output from the detection means. And a synchronization signal flag FA for determining a write timing for writing a multicolor image on the photoconductor in synchronization with the synchronization signal (determined by the CPU 2 of the image controller 1 based on a control program stored in the ROM 3). ~ In synchronization with any of the detection outputs sequentially output from FF, the CPU 2 determines the writing timing for writing the multicolor image on the photoconductor, and a plurality of sheets are printed on the intermediate transfer body. Image is it possible to transfer an image of a plurality of sheets from any position that does not cause interference without, and the image missing each other.

Correspondence between this embodiment and each step of the fifth invention and its action will be described below with reference to FIG.

A fifth aspect of the invention is provided with a plurality of synchronizing members which show a predetermined position in the sub-scanning direction in accordance with the movement of the endlessly moving intermediate transfer member, and is obtained by transferring each color image onto the intermediate transfer member. In a method of writing an image in a multicolor image forming apparatus, which transfers a color transfer image to a fed recording medium to form an image, a detecting step of detecting each of the synchronizing members at a predetermined position,
The CPU 2 of the image controller 1 executes the ROM 3 and the determining step of determining the writing timing for writing the multicolor image on the photoconductor in synchronization with one of the detection outputs that are sequentially output.
Executed based on the control program stored in, without interfering with each other on the intermediate transfer member.
In addition, it is possible to automate the process of transferring a plurality of images from an arbitrary position that does not cause image loss.

[0071]

As described above, the first aspect of the present invention
According to the invention, the determining unit determines the writing timing for writing the multicolor image on the photosensitive member in synchronization with the predetermined detection output sequentially output from the detecting unit, so that a plurality of sheets on the intermediate transfer member can be written. It is possible to transfer a plurality of images from a predetermined position in which the images do not interfere with each other and the image loss does not occur.

According to the second aspect of the invention, the determining means determines the writing timing for writing the multicolor image on the photosensitive member in synchronization with any of the detection outputs sequentially output from the detecting means. It is possible to transfer the images for a plurality of sheets from an arbitrary position where the images for a plurality of sheets do not interfere with each other and the image loss does not occur.

According to the third invention, it is possible to transfer a plurality of images from a predetermined position on the intermediate transfer drum without interfering with each other and causing no image loss.

According to the fourth invention, each synchronizing member is detected at a predetermined position, and the writing timing for writing a multicolor image on the photoconductor is determined in synchronization with a predetermined detection output which is sequentially output. It is possible to automate the process of transferring a plurality of images from a predetermined position on the intermediate transfer member without interfering with each other and causing no image loss.

According to the fifth aspect of the invention, each synchronizing member is detected at a predetermined position, and the writing timing for writing the multicolor image on the photosensitive member is determined in synchronism with one of the detection outputs that are sequentially output. It is possible to automate the process of transferring a plurality of images from an arbitrary position on the intermediate transfer body without interfering with each other and causing no image loss.

Therefore, the throughput can be greatly improved by transferring a plurality of images from the positions where the images do not interfere with each other and from the position where the image break does not occur and continuously transferring the images to the recording medium. Produce the effect of.

[Brief description of drawings]

FIG. 1 is a schematic sectional view illustrating a configuration of a multicolor image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a multi-page image sequence in the multicolor image forming apparatus according to the present invention.

FIG. 3 is a diagram illustrating a multi-page image sequence in the multicolor image forming apparatus according to the present invention.

FIG. 4 is a principal block diagram illustrating a control configuration of a multicolor image forming apparatus according to the present invention.

FIG. 5 is a flowchart illustrating a print sequence of the multicolor image forming apparatus according to the present invention.

FIG. 6 is a schematic sectional view illustrating a configuration of a multicolor image forming apparatus showing a second embodiment of the present invention.

FIG. 7 is a diagram illustrating a multi-page image sequence in the multicolor image forming apparatus according to the present invention.

FIG. 8 is a diagram illustrating a multi-page image sequence in the multicolor image forming apparatus according to the present invention.

FIG. 9 is another principal block diagram for explaining the control configuration of the multicolor image forming apparatus according to the present invention.

FIG. 10 is a flowchart illustrating another print sequence of the multicolor image forming apparatus according to the present invention.

FIG. 11 is a schematic sectional view illustrating a configuration of a conventional electrophotographic multicolor image forming apparatus.

[Explanation of symbols]

 1 Image Controller 2 CPU 204 Scanner Unit 205 Photosensitive Drum 206 Rotating Developer Unit 207 Intermediate Transfer Body 210 Flag 211 Flag

Claims (5)

[Claims] 1. A multicolor image forming apparatus for forming an image by transferring a multicolor transfer image obtained by transferring each color image onto an endlessly moving intermediate transfer member to form an image. In synchronization with a plurality of synchronization members that indicate a predetermined position in the sub-scanning direction according to the movement of the body, a detection unit that detects each of the synchronization members at a predetermined position, and a predetermined detection output that is sequentially output from the detection unit. A multicolor image forming apparatus comprising: a determining unit that determines a writing timing for writing a multicolor image on a photoconductor. 2. A multicolor image forming apparatus for forming an image by transferring a multicolor transfer image obtained by transferring each color image onto an endlessly moving intermediate transfer member to form an image. A plurality of synchronization members that indicate arbitrary positions in the sub-scanning direction according to the movement of the body, a detection unit that detects each of the synchronization members at a predetermined position, and a detection output that is sequentially output from the detection unit. And a deciding unit for deciding a writing timing for writing a multicolor image on the photoconductor. 3. The multicolor image forming apparatus according to claim 1, wherein the intermediate transfer member is an intermediate transfer member drum. 4. A multicolor transfer image obtained by transferring each color image onto the intermediate transfer member, comprising a plurality of synchronizing members that show a predetermined position in the sub-scanning direction according to the movement of the endlessly moving intermediate transfer member. In an image writing method of a multicolor image forming apparatus for forming an image by transferring to a fed recording medium, a detection step of detecting each of the synchronizing members at a predetermined position and a predetermined detection output sequentially output are performed in synchronization. And a writing step of writing a multicolor image on the photoconductor, the image writing method of the multicolor image forming apparatus. 5. A multicolor transfer image obtained by transferring each color image onto the intermediate transfer member, comprising a plurality of synchronizing members that show a predetermined position in the sub-scanning direction according to the movement of the endlessly moving intermediate transfer member. In an image writing method of a multicolor image forming apparatus for forming an image by transferring to a fed recording medium, a detection step of detecting each of the synchronizing members at a predetermined position and a detection output which is sequentially output are synchronized. And a determining step of determining a writing timing for writing the multicolor image on the photoconductor.