JPH08334953A - Image processor - Google Patents

Abstract

PURPOSE: To provide an image processor which can increase the throughput without speeding up a process in multicolor image formation using an intermediate transfer body. CONSTITUTION: A black developing unit 144 is fixedly disposed opposite to an image carrier 1, and magenta, cyan and yellow developing units 141-143 are disposed in rotary developing unit 4b so that each can be positioned opposite to the image carrier 1 by selecting alternatively. During development by the black developing unit 144, the developing unit having color to be used in the subsequent development is made ready for use being positioned opposite to the image carrier within in the rotary developing unit 4b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus, for example, an image processing apparatus for forming a toner image of another color on a transfer material by using an intermediate transfer member.

[0002]

2. Description of the Related Art FIG. 9 shows a schematic configuration of an image processing apparatus for forming a multicolor image using a conventional intermediate transfer member. This image processing apparatus is a copying machine or a laser beam printer using an electrophotographic process. The configuration and operation of the image processing apparatus shown in FIG. 9 will be briefly described below.
In the conventional image processing apparatus, the following (1) to
By following the operation described in (4), a multicolor image is formed on the intermediate transfer member.

(1) A rotary drum type electrophotographic photosensitive member (hereinafter referred to as "photosensitive drum") 1 as an image bearing member is disposed inside the main body of the apparatus (hereinafter referred to as "inside the apparatus"). 1 is rotationally driven in the direction of arrow R1 at a predetermined peripheral speed (process speed), and each image forming process described later is repeatedly performed on the surface thereof.

The photosensitive drum 1 is charged to have a predetermined polarity and a predetermined surface potential by a charging device 2 such as a corona discharger in the course of rotation in the direction of arrow R1, and then the exposure section 3 is exposed.
(Image-forming exposure optical system based on color separation of color original image,
The first color component image (for example, the first color component image of the target color image is received by receiving the image exposure L by the scanning exposure optical system by the laser scanner which outputs the laser beam modulated corresponding to the time series electric digital pixel signal of the image information). , M (magenta) component image) is formed.

Next, the electrostatic latent image is developed by the toner (colored charged particles) of magenta M which is the first color, for example, by the first developing device 41 (magenta developing device) of the rotary developing device 4. An endless intermediate transfer belt 50 as an intermediate transfer member is arranged diagonally below the photosensitive drum 1, and the intermediate transfer belt 50 includes one conductive roller 6 and three turn rollers 7a, 7b, 7c. It is suspended around a total of four rollers. The conductive roller 6 holds the intermediate transfer belt 50 in a state of being pressed against the photosensitive drum 1 with a predetermined pressing force.

The intermediate transfer belt 50 is rotationally driven in the direction of arrow R5 at the same peripheral speed as the photosensitive drum 1, and the conductive roller 6 is formed on the photosensitive drum 1 by a first bias power source 61. Image (hereinafter "toner image"
A transfer bias having a reverse polarity (plus) to the toner charging polarity (negative in this embodiment) is applied.
The intermediate transfer belt 50 is, for example, a dielectric film of polyester, polyethylene or the like, or a composite layer type dielectric film of which the back surface (inner surface side) such as medium resistance rubber is lined with a conductor. The first formed and carried on the surface of the photosensitive drum 1 described above.
The magenta toner image of the color is sequentially intermediate-transferred to the outer surface of the intermediate transfer belt 50 in the process of passing through the transfer portion by the electric field formed by applying the transfer bias to the conductive roller 6.

On the other hand, the surface of the photosensitive drum 1 which has finished transferring the magenta toner image of the first color onto the intermediate transfer belt 50 is cleaned by the cleaning device 14.

Similarly, (2) charging on the photosensitive drum 1 → image exposure L corresponding to a second color component image (for example, a cyan component image) → cyan C of the second developing device 42 (cyan developing device) Developing with the toner of → the transfer of the formed cyan toner image of the second color onto the intermediate transfer belt 50 → cleaning of the surface of the photosensitive drum 1 by the cleaning device 14.

(3) Charging on the photosensitive drum 1 → image exposure L corresponding to a third color component image (for example, yellow component image) → yellow Y of the third developing device 43 (yellow developing device)
With the toner of → the transfer of the formed yellow toner image of the third color onto the intermediate transfer belt 50 → the photosensitive drum 1
Cleaning the surface with the cleaning device 14.

(4) Charging on the photosensitive drum 1 → image exposure L corresponding to a fourth color component image (for example, black component image) → black B of the fourth developing device 44 (black developing device)
Development with the toner of k → Transfer of the formed black toner image of the fourth color to the intermediate transfer belt 50 → Cleaning of the surface of the photosensitive drum 1 by the cleaning device 14.

By sequentially executing the image forming and transfer processes of (1) to (4), the above-mentioned four toner images (magenta, cyan, yellow, and black toners) are formed on the outer surface of the intermediate transfer belt 50. The image) is superimposed and transferred to form a composite color toner image (mirror image) corresponding to the target color image.

Next, from the paper feed cassette 9 to the paper feed roller 1
The transfer material (paper sheet) P is separated and conveyed by 0 by 0, passes through the registration roller pair 11 and the transfer guide 12, and is transferred to the transfer portion formed by the transfer device 7 (corona charger) and the turn roller 7a. It is fed at a predetermined timing.

Here, a bias (negative in this example) having the same charging polarity of toner as 0 V or the reverse of the transfer process is applied to the conductive roller 6 from the second bias power source 62. Further, on the transfer material P fed at a predetermined timing, when the toner image is transferred, the third bias power source 71 transfers the toner charging polarity (negative in this example) and reverse polarity (plus). A bias is applied to the transfer device 7.

By repeating the above-described series of image forming processes, the transfer composite color images are sequentially intermediate-transferred onto the intermediate transfer belt 50, and the intermediate-transferred color toner images are successively sent to the transfer section. The final transfer is performed on the subsequent transfer material P that comes.

When the transfer process is completed, the intermediate transfer belt 50 is supplied with 0 V by the fourth bias power source 72.
Alternatively, a transfer bias (negative) having the same polarity as the toner charging polarity (negative in this example) is applied.

The transfer material P on which the toner image on the intermediate transfer belt 50 has been transferred through the transfer portion is introduced into the fixing device 15 via the conveyance guide 13 and is applied to the fixing roller 16 which is heated and controlled to a predetermined value. The toner image is fixed by being heated and pressed by the pressure roller 17, and is output as a final color image formed product.

On the other hand, the intermediate transfer belt 5 after the toner image transfer
0 is cleaned by the belt cleaning device 8.
The belt cleaning device 8 is a cleaning device for the intermediate transfer belt 50 and is normally held in a non-acting state with respect to the intermediate transfer belt 50. The outer surface of the intermediate transfer belt 50 is cleaned by operating the cleaning device 8 on the outer surface of the transfer belt 50.

Incidentally, depending on the outer peripheral length of the transfer belt 50,
It is also possible to carry two or more transfer materials P at one time and form two images at once by one rotation.

In the conventional image processing apparatus shown in FIG. 9 described above, the structure including the intermediate transfer belt 50 as an intermediate transfer member has been described as an example. However, instead of the intermediate transfer belt 50, for example, It is also possible to adopt a configuration including an intermediate transfer drum made of a metal hollow cylinder. In any case, after the transfer onto the transfer material P by one rotation of the intermediate transfer drum 50, for example, the developing device of a predetermined color of the rotary developing device 4 (for example, the magenta first developing device 41) is transferred to the photosensitive drum 1. They were arranged so as to face each other and prepared for the next development.

[0020]

However, in the above-mentioned conventional example, the number of images that can be formed within a predetermined time (hereinafter referred to as "throughput" refers to the number of images that can be formed in one minute) is a single color and Regardless of multicolor image formation, it depends on the process speed, and therefore, the process speed must be increased in order to increase the throughput. When the process speed is increased in the conventional image processing apparatus, the following problems occur.

(1) Since the cleaning blade or the like is in contact with the photosensitive drum, the load on the photosensitive drum is increased and the surface layer of the photosensitive drum is further scraped, so that the durability of the photosensitive drum is deteriorated. That is, the life of the photosensitive drum is shortened. (2) Since the developing device for each color has to face the photosensitive drum in accordance with the throughput, the load on the rotary unit for rotating the developing device is increased, and the photosensitive drum is further On the other hand, it was difficult to make them face each other with a predetermined space. Therefore, it is necessary to increase the strength of the rotary unit or the entire device in order to make the respective color developing devices face each other with a predetermined distance from the photosensitive drum.

Therefore, in order to solve these problems, the image processing apparatus is required to have further durability.

The present invention has been made in order to solve the above-mentioned problems, and an object thereof is to provide an image processing apparatus capable of increasing the throughput without increasing the process speed. .

[0024]

As one means for achieving the above object, the image processing apparatus of the present invention has the following configuration.

That is, a black developing device, a rotary developing device having at least two color developing devices, and an intermediate transfer member are arranged around the image bearing member that is rotatably instructed, and the image developing member is sequentially arranged on the image bearing member. In the image processing device, the formed multi-color images are sequentially intermediate-transferred to the intermediate transfer body, and the multi-color images intermediately transferred onto the intermediate transfer body are collectively transferred to a transfer material. It is possible to carry two or more sets of images on the body, and while the 2n-th (n is an integer) image is being formed by the black developing device used as the final color for image formation, It is characterized in that a developing device housed in a rotary developing device, which is used for image formation of 2n + 1th sheet, is opposed to the image carrier to perform the next image formation.

For example, the developing device in the rotary developing device is
It is characterized in that the developing color can be selectively selected by rotation.

For example, when monochromatic image formation is continuously performed by the black developing device, the intervals of the plurality of images transferred onto the intermediate transfer member are all equal.

For example, the development preparation by the developing device in the rotary developing device is started before the completion of the development by the black developing device.

Further, a black developing device, a rotary developing device having a developing device of at least two colors, and an intermediate transfer member are arranged around the image bearing member rotatably instructed, and the image developing member is sequentially mounted on the image bearing member. In the image processing device, the formed multi-color images are sequentially intermediate-transferred to the intermediate transfer body, and the multi-color images intermediately transferred onto the intermediate transfer body are collectively transferred to a transfer material. It is possible to carry two or more sets of images on the body, and after the completion of the 2nth (n is an integer) image formation in the developing device in the rotary developing device used as the final color of the image formation, 2 with a black developing device used as a color
The feature is that the image formation of the (n + 1) th sheet is continuously performed.

For example, the developing device in the rotary developing device is
It is characterized in that the developing color can be selectively selected by rotation.

For example, when monochromatic image formation is continuously performed by the black developing device, the intervals of the plurality of images transferred onto the intermediate transfer member are all equal.

For example, the development preparation by the developing device in the rotary developing device is started before the completion of the development by the black developing device.

Further, there is provided an image processing apparatus for forming a multi-color image by sequentially forming an image on an image carrier by a multi-color developing device and sequentially transferring the image on a transfer body. Among the developing devices, a developing device of a predetermined color is fixed so as to face the image carrier, and a developing device of another color is arranged so as to face the image carrier by rotation, and development by the developing device of the predetermined color is performed. Before the end, preparation for development by the developing device for the other color is started.

For example, the developing device for the other color has at least 2
The color developing device is provided, and the developing color can be selectively selected by rotation.

For example, the transfer body is characterized in that a plurality of images can be formed on the outer periphery thereof.

For example, the transfer body is characterized in that two images can be formed on the outer periphery thereof.

For example, during the image formation by the developing device of the predetermined color, the developing device of the color to be used next among the developing devices of the other colors stands by so as to face the image carrier. .

For example, after the image formation by the developing device of the other color is completed, the image forming by the developing device of the predetermined color is performed.

For example, when monochromatic image formation of the predetermined color is continuously performed, the intervals of the plurality of images transferred on the transfer body are all the same.

For example, it is characterized in that the monochromatic image formation by the predetermined color and the monochromatic image formation by any one of the other colors are alternately performed.

For example, the predetermined color is black.

[0042]

With the above construction, in the image processing apparatus for forming a multicolor image by using the intermediate transfer member, the developing device of a predetermined color (black) is fixed and the developing devices of other colors are selectively rotated. By making the selection possible, it is possible to prepare for forming a multicolor image during the image formation with the predetermined color. Therefore, the peculiar effect that the overall throughput can be increased without changing the process speed can be obtained.

[0043]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described in detail below with reference to the drawings.

<First Embodiment> FIG. 1 shows a block diagram of an image processing apparatus of the present embodiment. In FIG. 1, the same components as those of FIG. 9 shown in the conventional example are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 1, the charging device 2 and the exposure unit 3 are arranged around the photosensitive drum 1 as an image carrier, which is the same as the conventional example, but the developing device and the intermediate transfer member are conventional. Very different from the example. However, in FIG. 1, the reflection mirror 31 is shown separately from the exposure unit 3 in order to make it easier to understand the effect of the present invention.

In this embodiment, as the intermediate transfer member,
Instead of the intermediate transfer belt shown in FIG. 9 in the conventional example,
The intermediate transfer drum 5 is used. The intermediate transfer drum 5 is configured by providing an intermediate transfer layer 52 on the surface layer of a metal hollow cylinder 51, abutted from below the photosensitive drum 1, and driven to rotate in the direction of arrow R5. Intermediate transfer drum 5
At the hollow cylinder 51, the first bias power source 6
The first and second bias power sources 62 are connected to the transfer device 7, which faces the intermediate transfer drum 5 from below.
The third bias power source 71 and the fourth bias power source 72 are connected.

The developing device of the present embodiment is a black (Bk) developing device (hereinafter referred to as "Bk developing device") fixedly arranged on the upstream side in the rotation direction of the photosensitive drum 1 (direction of arrow R1). It is composed of a fixed developing device 4a composed of 144 and a rotary developing device 4b having a developing device for other three colors rotatably arranged on the downstream side. The rotary developing device 4b includes a rotating body that rotates in the direction of arrow R4 and three developing devices mounted on the rotating body, that is, toners of magenta (M), cyan (C), and yellow (Y), respectively. Developing units 141, 142, 143 (hereinafter referred to as “M developing unit 141, C developing unit 142, Y developing unit 14
3 ”).

The Bk developing device 144 is fixedly arranged between the exposure unit 3 on the upstream side and the rotary developing device 4b on the downstream side so as to separate them.

By rotating in the direction of arrow R4, the rotary developing device 4b disposes the developing device (M developing device 141 in FIG. 1) for development at the developing position facing the surface of the photosensitive drum 1. Rotational direction R4 of the rotary developing device 4b
Is the same as the rotation direction R1 of the photosensitive drum 1, and is opposite to the rotation direction of the intermediate transfer drum 5 (direction of arrow R5).

The rotation direction of the rotary developing device 4b is indicated by an arrow R.
If the four developing directions are set and the developing order of the four colors is performed in the order of M → C → Y → Bk as in the conventional example, the M developing device 141, the C developing device 142, and Y of the rotary developing device 4b. The developing device 143 is arranged as shown in FIG.
Along the rotation direction (direction of arrow R4) of the M developing device 141,
The Y developing device 143 and the C developing device 142 are in this order.

The image forming operation in the image processing apparatus of this embodiment shown in FIG. 1 will be described in detail below by dividing it into processes (1) to (5). Incidentally, FIG. 1 shows the M developing device 1 out of the three developing devices in the rotary developing device 4b.
41 shows the state of standby at the current position.

(1) First, a latent image of an M image of the first color is formed on the photosensitive drum 1, and development is performed in the state shown in FIG. The M toner image on the photosensitive drum 1 which is visualized with the M toner by the developing device 141 is in the direction of arrow R1 (counterclockwise).
While being rotated, the intermediate transfer is sequentially performed on the outer peripheral surface of the intermediate transfer drum 5. Then, the surface of the photosensitive drum 1 on which the transfer of the M toner image of the first color is finished to the intermediate transfer drum 5 is
It is cleaned by the cleaning device 14.

(2) Subsequently, a latent image of the C image of the second color is formed, but in order to carry out the C development, the rotary developing device 4 is used.
b rotates in the direction of arrow R4 (the same counterclockwise direction as the photosensitive drum 1). Then, similarly, (3) C development → intermediate transfer of C toner image onto the intermediate transfer drum 5 → cleaning of the surface of the photosensitive drum 1 by the cleaning device 14.

(4) Then, as in (2) to (3), Y
Phenomenon → Intermediate transfer of Y image to the intermediate transfer drum 5 → Cleaning of the surface of the photosensitive drum 1 by the cleaning device 14.

(5) Next, the image exposure L corresponding to the fourth Bk component image L → development with Bk toner of the Bk developing device 144 → intermediate transfer of the Bk toner image to the intermediate transfer drum 5 → the surface of the photosensitive drum 1 Cleaning with the cleaning device 14.

By sequentially executing the image forming and transfer processes of the above (1) to (5), the above-described four color toner images (magenta, cyan, yellow, black) are formed on the outer peripheral surface of the intermediate transfer drum 5. Are superimposed and transferred to form a synthetic toner image (mirror image) corresponding to the target color image.

Thereafter, through the same process as described with reference to FIG. 9 in the conventional example, the four-color toner images on the intermediate transfer drum 5 are finally transferred to the transfer material P all together and further fixed. It is output as a color image formed product through the device 15.

In this embodiment, an intermediate transfer drum 5 having an outer shape of 180 (mm) or more is used, and two A4 size images are horizontally placed on the intermediate transfer body, and a maximum of A3 size image is once. It can be carried on. The unique effects of this embodiment will be described below with reference to FIG.

FIG. 2 shows a timing chart at the time of forming an image in the image processing apparatus of this embodiment in comparison with the conventional example.

For example, consider a case where A4 size images are continuously formed, that is, a case where two A4 size images are formed on the intermediate transfer drum 5 at a time. At this time, regardless of the conventional example and the present example, it is necessary to open a physical interval between the two images on the intermediate transfer drum 5 in both cases. Therefore, due to this predetermined physical interval, a time interval without development occurs, which time interval is indicated by S1 and S2 in FIG. Hereinafter, the physical interval between the plurality of images on the intermediate transfer drum 5 is referred to as "paper interval". This sheet interval is a distance provided so that the transfer material P can be stably separated from the intermediate transfer drum 5 and the transfer device 7 when the toner image on the intermediate transfer drum 5 is transferred onto the transfer material P. .

The time interval S1 shown in FIG. 2 corresponds to the minimum distance required for stable separation of the transfer material P as described above, but the time interval S2 will be described later with respect to S1. Since it further includes the rotation time of the developing device,
It will be longer than 1. Hereinafter, for example, the time interval S1 corresponding to the space between the papers will be referred to as "paper space S1".

Here, in the case of the above-mentioned conventional example, the nth and (n + 1) th images are first formed on the intermediate transfer drum 5 and transferred to the transfer material P, and then further continuous. Consider the case of forming the (n + 2) th image and the (n + 3) th image. Note that n is an integer. Then, between the (n + 1) th sheet and the (n + 2) th sheet, from the Bk developing device 144 used for developing the final color of the (n + 1) th sheet to the first (n + 2) th sheet. Rotate the rotary developing device 4 to the M developing device 141 required for color development,
It is necessary to arrange the developing device 141 at a predetermined position. Therefore, it is necessary to provide a stable predetermined paper distance between the (n + 1) th image and the (n + 2) th image. That is, within the time required for this paper interval (paper interval S2), the rotary developing device 4 is rotated to switch from the Bk developing device 144 to the M developing device 141.

However, in the image processing apparatus of this embodiment, the Bk developing device 144 is fixedly held by the fixed developing device 4a at a position opposed to the photosensitive drum 1, and the remaining toner developing devices 141 to 143 for the respective colors rotate. It is stored in the developing device 4b. Therefore, the final color of the (n + 1) th sheet is B
While developing with the k developing device 144, the rotary developing device 4b is rotated to move the M developing device 141 for developing the next (n + 2) th first color to a predetermined position with respect to the photosensitive drum 1. They can be arranged facing each other. Therefore, compared with the case of the above-mentioned conventional plate example, the (n + 1) th sheet and the (n + 2) th sheet
Between the images of the first sheet, sufficient image formation can be performed with only the sheet interval S1 shorter than the sheet interval S2.

Therefore, according to the present embodiment, the sheet intervals S2 and S1 are
Since it is possible to form an image even on the sheet interval S3, which is a difference between and, it is possible to shorten the processing time.

Here, the table in FIG. 3 shows the results of a concrete comparison of the throughput in the case of forming a full-color image in this embodiment with that of the conventional example. The operating conditions in each image processing apparatus that performs image formation in this case are as follows.

The process speed of each image processing apparatus is set to a value that can realize a throughput of 6 sheets in the conventional full-color image processing apparatus, and the outer diameter of the photosensitive drum 1 is 60.
(Mm), when the outer diameter of the intermediate transfer drum 5 is 180 (mm), 120 (mm / sec) is the standard process speed, and the interval corresponding to the sheet interval S1 at that time is 50 (m).
m).

Under the above conditions, the throughput when the outer diameter of the intermediate transfer drum 5 was changed was compared between the conventional example and this example. The developing color order, the image forming process order, etc. are as described above. In the image processing apparatus of the conventional example, when the intermediate transfer member is the intermediate transfer belt 50, the entire length of the intermediate transfer belt 50 is set to the intermediate value. The length was adjusted to match the outer diameter of the transfer drum 5.

The comparison based on the difference in outer diameter of the intermediate transfer drum 5 is that the time required for replacing each color developing device by the rotation of the rotary developing device 4b is the (n + 1) th sheet. It depends on the (n + 2) th sheet interval, and when the outer diameter of the intermediate transfer drum 5 changes, this sheet interval also changes, and if the outer diameter is larger, more stable developing device exchange can be performed. This is because it also greatly affects the throughput in the example.

Therefore, FIG. 3 shows the results of throughput in the conventional example and the present example when the outer diameter of the intermediate transfer member is changed. According to FIG. 3, when the outer diameter of the intermediate transfer drum 5 is 180 (mm), the throughput is 6 in the conventional example, whereas it is 6.19 in the present embodiment. The outer diameter of 5 is 190,200
When the value becomes large (mm), the throughput is 6 sheets in the conventional example and there is no change, whereas in the present embodiment, the throughput is increased to 6.25 sheets and 6.38 sheets.

As described above, according to this embodiment, it is possible to increase throughput in continuous multicolor image formation without increasing process speed.

In this embodiment, the image formation by the Bk developing device 144 is described as the final color (fourth color), but the same applies when the image forming by the Bk developing device 144 is the first color. The effect is obtained.

<Second Embodiment> The second embodiment according to the present invention will be described below. Since the device configuration of the image processing device of the second embodiment is the same as that of the first embodiment described above, the description thereof will be omitted.

In the above-described first embodiment, the case of performing continuous multicolor image formation has been described, but in the second embodiment, the case of performing continuous single color image formation will be described.

FIG. 4 shows a timing chart when a black monochromatic image is formed in the second embodiment in comparison with the conventional example. Incidentally, S1 and S2 in FIG. 4 are the same as those shown in FIG. 2 in the above-described first embodiment. That is, the two transfer materials P can be attached to the intermediate transfer member, and the sheet interval between the n-th sheet and the n + 1-th sheet is S1, and the sheet interval between the n + 1-th sheet and the n + 2-th sheet is S2. .

According to FIG. 4, in the case of the conventional example shown in the upper stage, the writing positions of the nth image and the (n + 2) th image on the intermediate transfer drum 5 are set to be common for each color. I was there. Therefore, the sheet interval S2 is the time required to replace the developing device by the rotary developing device 4, and is longer than the sheet interval S1.

However, in the second embodiment shown in the lower part of FIG. 4, since the image writing position on the intermediate transfer drum 5 is set to an arbitrary position, the Bk developing device 144 is used in the case of monochromatic image formation. Since it is fixed, it is not necessary to replace the developing device, and it is sufficient to always maintain the predetermined sheet interval S1.
FIG. 4 shows the single-color image formation when the outer diameter of the intermediate transfer drum 5 is 180 (mm). However, while the image formation of seven sheets is completed in the conventional example, it is 8 in the second embodiment. It can be seen that the image formation of one sheet is completed. That is, the throughput as a whole is improved.

The table of FIG. 5 shows the results of a concrete comparison of the throughput in the case of forming a monochromatic image in the second embodiment with that of the conventional example. In this case, the operating conditions in each image processing apparatus that performs image formation are:
As in the case of FIG. 3 of the first embodiment described above, the process speed is 120 (mm / sec).

FIG. 5 shows the results of the throughputs of the conventional example and the second embodiment when the outer diameter of the intermediate transfer member is changed. According to FIG. 5, the outer diameter of the intermediate transfer drum 5 is 1
In the case of 80 (mm), the throughput was 24 sheets in the conventional example, while it was 27 sheets in the second example, and the outer diameter of the intermediate transfer drum 5 was 190,200 (m).
m), the throughput is 24 sheets in the conventional example and remains unchanged, whereas the throughput is increased to 27.6 sheets and 30 sheets in this embodiment.

As described above, according to the second embodiment, it is not necessary to switch the developing device even in continuous monochromatic image formation, and therefore continuous image formation can be performed with a constant paper distance. Therefore, it is possible to increase the throughput of the entire apparatus without increasing the process speed.

<Third Embodiment> The third embodiment of the present invention will be described below. Since the device configuration of the image processing device of the third embodiment is similar to that of the first embodiment described above, the description thereof will be omitted.

In the image processing apparatus described in the first embodiment, the Bk developing device 144 is fixed, so that B
During image formation by the k developing device 144, the color developing device housed in the rotary developing device 4b can be made to oppose the photosensitive drum 1 at an appropriate position for the next image formation. This example will be described below with reference to FIGS. 6 and 7.

FIG. 6 and FIG. 7 are basically the same as FIG. 1 shown in the above-mentioned first embodiment, but show how an image is formed on the photosensitive drum 1 by the Bk developing device 144. . Here, in the first embodiment, as shown in FIG. 6, during the image formation by the Bk developing device 144, the color developing devices 141 to 143 are located at positions facing the photosensitive drum 1 in the rotary developing device 4b. It wasn't there. Therefore, when the timing for actually forming an image with each color is reached, the developing device for the color is opposed to the photosensitive drum 12, so that the rotary developing device 4b performs a rapid rotation operation. That is, since the abrupt rotation and stop operations are repeated in the rotary developing device 4b, a slight impact is generated in the device, such as the rotary developing device 4b itself and the opposing photosensitive drum 1. Therefore, the formed image may be slightly blurred.
Image quality may be degraded.

Therefore, in the third embodiment, as shown in FIG. 7, during the image formation by the Bk developing device 144, the developing device to be used next (for example, the M developing device 141) is changed to the photosensitive drum 1.
In advance, and when the timing for forming an image with the M developing device 141 is reached, the image forming operation for M colors is started.

As a result, in the third embodiment, while the image is being formed by the Bk developing device 144, the color developing device to be used for the next image forming is arranged at a predetermined position, so that the above-mentioned operation is performed. It is possible to reduce the impact of the rotary developing device 4b and the photosensitive drum 1 or the entire apparatus main body caused by the alignment due to the rapid rotation of the rotary developing device 4b, and the image formation can be started more smoothly.

As described above, according to the third embodiment, it is possible to suppress the blurring during the image formation due to the impact generated by the rotation of the rotary developing device 4b and form a higher quality image. Is possible.

<Fourth Embodiment> The fourth embodiment of the present invention will be described below. The image processing apparatus according to the fourth embodiment has the same device configuration as that of the first embodiment described above, and thus the description thereof will be omitted.

In the fourth embodiment, when a plurality of images are successively formed, a Bk monochromatic image is formed by the Bk developing unit 144 and each of the color developing units 141 to 143 housed in the rotary developing unit 4b. It is characterized in that monochromatic image formation for each color is performed alternately.

When the color developing devices for four colors are housed in one rotary developing device 4 as in the conventional example described above, Bk
To form toner images of other colors while continuously forming toner images, the rotary developing device 4 must be rotated. Therefore, since the rotation requires a predetermined time, the throughput as a whole is reduced. Further, in the case where the color developing devices are housed in the rotational developing device 4 in the illustrated color order, when the M toner image is formed after the Bk toner image is formed and when the C toner image is formed, Further, the rotation distance in the rotary developing device 4 is different from that in the case of forming the Y toner image. That is, since the required paper interval differs depending on the color developing device selected next, the throughput of the entire apparatus is greatly affected by the color developing device selected.

However, according to the fourth embodiment, no matter which color developing device is selected, while the Bk developing device 144 is forming the Bk toner image, the rotary developing device 4b is used.
Can be rotated so that the arbitrarily selected color developing device can be opposed to the photosensitive drum 1. Therefore, it becomes possible to form a Bk single color toner image continuously while forming a single color image other than Bk without lowering the throughput of the apparatus.

FIG. 8 shows a timing chart at the time of continuous image formation in the fourth embodiment. In addition, S in FIG.
1 is the same as that shown in FIG. 2 in the above-mentioned first embodiment. That is, the two transfer materials P can be attached to the intermediate transfer member, and the space between the nth sheet and the (n + 1) th sheet is indicated by S1.

The upper part of FIG. 8 shows the timing when continuous image formation is performed with Bk single color in the fifth embodiment, and the lower part shows image formation of Bk and other colors alternately (Bk).
→ M → Bk → C → Bk → Y → Bk → ...). The example shown in FIG. 8 is based on standard process conditions (the outer diameter of the intermediate transfer drum 5 is 180 (mm) and the process speed is 120 (mm)) as in the case of FIG. 3 shown in the first embodiment. Is.

According to FIG. 8, the throughput is 24 in both cases shown in the upper and lower rows. That is, even when Bk and other colors shown in the lower part of FIG. 8 are alternately formed continuously, the image formation can be performed without lowering the throughput as compared with the case of continuously forming Bk single color shown in the upper part.

As described above, according to the fourth embodiment, B
Even if continuous image formation is alternately performed with k and other colors, throughput is not reduced.

In each of the above-mentioned embodiments, the example in which the Bk developing device is fixed and the developing devices of other colors are rotated has been described, but the developing device to be fixed is of course limited to the Bk developing device. However, it is not limited to this, and can be appropriately changed depending on the usage of the image processing apparatus, for example, by fixing the developing device for the toner of the most frequently used color.

The positions of the fixed developing device and the rotary developing device may be reversed.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of one device. Further, it goes without saying that the present invention can be applied to the case where it is achieved by supplying a program to a system or an apparatus.

[0097]

As described above, according to the present invention, in an image processing apparatus for forming a multicolor image using a transfer member, a developing device of a predetermined color is fixed and a developing device of another color is rotated. By making it selectable alternatively, it is possible to prepare for multi-color image formation during image formation with the predetermined color, and thus throughput can be increased without changing the process speed. Become.

[0098]

[Brief description of drawings]

FIG. 1 is a side sectional view of an image processing apparatus according to an embodiment of the present invention.

FIG. 2 is a timing chart when color images are continuously formed in this embodiment.

FIG. 3 is a table showing the throughput for each outer diameter of the intermediate transfer drum in this embodiment.

FIG. 4 is a timing chart at the time of continuous formation of a single color image in the second embodiment according to the present invention.

FIG. 5 is a table showing the throughput for each outer diameter of the intermediate transfer drum in the second embodiment.

FIG. 6 is a diagram for explaining the operation of the rotary developing device in the fourth embodiment of the present invention.

FIG. 7 is a diagram for explaining the operation of the rotary developing device in the fourth embodiment.

FIG. 8 is a timing chart at the time of continuous image formation in the fourth embodiment.

FIG. 9 is a side sectional view of a conventional image processing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Charging device 3 Exposure part 4 Rotating developing device 4a Fixed developing device 4b Rotating developing device 5 Intermediate transfer drum 7 Transfer device 8 Cleaning device for intermediate transfer member 14 Cleaning device for image carrier 15 Fixing device 16 Heating roller 17 Addition Pressure roller 50 Intermediate transfer belt 141 Magenta developing device 142 Cyan developing device 143 Yellow developing device 144 Black developing device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Hiroshima 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kazuhisa Kamo 3-30-2 Shimomaruko, Ota-ku, Tokyo Kyano Within the corporation

Claims (17)

[Claims] 1. A black developing device, a rotary developing device having a developing device of at least two colors, and an intermediate transfer member are arranged around an image bearing member that is rotatably instructed, and are sequentially arranged on the image bearing member. In the image processing device, the formed multi-color images are sequentially intermediate-transferred to the intermediate transfer body, and the multi-color images intermediately transferred onto the intermediate transfer body are collectively transferred to a transfer material. It is possible to carry two or more sets of images on the body, and while the 2n-th (n is an integer) image is being formed by the black developing device used as the final color for image formation, 2n +
An image processing apparatus, comprising: a developing device, which is used for forming an image of a first sheet, and which is housed in a rotary developing device, is opposed to the image carrier to perform the next image formation. 2. The image processing apparatus according to claim 1, wherein the developing device in the rotary developing device is capable of selectively selecting a developing color by rotation. 3. An image forming apparatus according to claim 1, wherein when a monochrome image is continuously formed by the black developing device, a plurality of images transferred on the intermediate transfer member have an equal interval.
The image processing device described. 4. The image processing apparatus according to claim 1, wherein preparation for development by a developing device in the rotary developing device is started before completion of development by the black developing device. 5. A black developing device, a rotary developing device having a developing device of at least two colors, and an intermediate transfer member are arranged around the image bearing member rotatably instructed, and the image developing member is sequentially arranged on the image bearing member. In the image processing device, the formed multi-color images are sequentially intermediate-transferred to the intermediate transfer body, and the multi-color images intermediately transferred onto the intermediate transfer body are collectively transferred to a transfer material. It is possible to carry two or more sets of images on the body, and after the completion of the 2nth (n is an integer) image formation in the developing device in the rotary developing device used as the final color of the image formation,
An image processing apparatus characterized in that a black developing device used as a color image continuously forms an image of 2n + 1th sheet. 6. The image processing apparatus according to claim 5, wherein the developing device in the rotary developing device can selectively select a developing color by rotation. 7. The image forming apparatus according to claim 5, wherein when a monochrome image is continuously formed by the black developing device, the intervals of the plurality of images transferred onto the intermediate transfer member are all the same.
The image processing device described. 8. The image processing apparatus according to claim 5, wherein preparation for development by a developing device in the rotary developing device is started before completion of development by the black developing device. 9. An image processing apparatus for forming a multi-color image by sequentially forming images on an image bearing member by a multi-color developing device and sequentially transferring the images on a transfer member. Among the developing devices, a developing device of a predetermined color is fixed so as to face the image carrier, and a developing device of another color is arranged so as to face the image carrier by rotation, and development by the developing device of the predetermined color is performed. An image processing apparatus, wherein preparation for development by the developing device for the other color is started before the end. 10. The image processing apparatus according to claim 9, wherein the developing device for the other color includes a developing device for at least two colors, and the developing color can be selectively selected by rotation. 11. The image processing apparatus according to claim 9, wherein the transfer body is capable of forming a plurality of images on its outer circumference. 12. The image processing apparatus according to claim 11, wherein the transfer body is capable of forming two images on its outer circumference. 13. A developing device for a color to be used next among the developing devices for other colors stands by so as to face the image carrier during image formation by the developing device for the predetermined color. The image processing apparatus according to claim 9. 14. The image processing apparatus according to claim 9, wherein the image formation by the developing device of the predetermined color is performed after the image formation by the developing device of the other color is completed. 15. The image processing apparatus according to claim 9, wherein when the single-color image formation of the predetermined color is continuously performed, the intervals of the plurality of images transferred on the transfer body are all the same. . 16. A monochrome image formation of the predetermined color,
The image processing apparatus according to claim 9, wherein monochromatic image formation by any one of the other colors is alternately performed. 17. The image processing apparatus according to claim 9, wherein the predetermined color is black.