JPH03149578A - Developing device of color image forming device - Google Patents

Abstract

PURPOSE:To speed up image formation by arranging (n) (n: interger larger four) developing units in one direction so that the movement quantity of each developing unit is up to an (n-2) pitch. CONSTITUTION:The developing device is equipped with the (n) (n: integer larger than four) developing units 10 - 13 which are arranged in one direction, a mov ing mechanism 16 which moves them reciprocally, and a movement control means which controls the movement order of the (n) developing units 10 - 13, and the (n) developing units 10 - 13 are arranged so that their movement quanti ties are up to the (n-2) pitch. Thus, the movement order of the (n) developing units 10 - 13 is controlled by a movement control means for the reciprocal movement, but they are arranged at up to the (n-2) pitch, so the movement time is shorter than the movement time of movement from the developing unit at one end to the developing unit at the other end to speed up the image formation.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention provides a method in which a plurality of developing devices are arranged in one direction,
The present invention relates to a developing device of a color image forming apparatus for forming a color image on recording paper using these developing devices.

[Conventional technology]

Generally, a developing device provided in a color image forming apparatus includes a developing device for each color. Various types of arrangement configurations of these developing units have been adopted in the past, and are broadly classified into fixed developing unit type and moving developing unit type.

In the fixed developer system, a developer corresponding to each color is fixed, but the diameter of the drum needs to be increased due to the space problem of arranging the developer around the photoreceptor drum. Further, the developing position with respect to the photosensitive drum is different for each color, which imposes restrictions on the configuration of the developing device and has the disadvantage that the developing device cannot be used in common.

On the other hand, in a moving developing device system in which each developing device is moved rotationally or linearly, a photosensitive drum with a small diameter similar to that used for black and white development can be used. Further, the developing device has the feature that it can be used in common for each color.

For the reasons mentioned above, there are various types of movable developer systems. As an example of the movable developer system, a conventional example in which each developer is moved in a straight line is shown in FIG.

The developing device 60 shown in this figure is capable of performing four-color full-color copying, and includes a magenta developing device 61.
, a cyan developer 02, a yellow developer 63, and a black developer 64 are arranged vertically in order from the top. Each of the developing units 61 to 64 is moved up and down by a moving mechanism to develop the electrostatic latent image on the photosensitive drum 65.

[Problem to be solved by the invention]

In the above-mentioned linear movement type developing device, when performing continuous full-color copying of four colors, the developed color is changed in a cycle of magenta-cyan-yellow → black → magentarcy, taking into account the components of the developer, etc. Development is performed while switching between the two. When performing such a round trip, when moving from black to magenta,
It has to move over cyan and yellow, and the moving distance is three pitches of the developing device.

By the way, when using the above-mentioned reciprocating method, the time it takes to move from one color developing device to the next color developing device is:
All must be at the same time to facilitate the control method. Therefore, as mentioned above, in order to be able to move the 3-pitch developing unit in the same time as the other 1-pitch movement, a large-capacity motor is required for the movement. In addition, using a small motor, the other one is
If the moving time is set for the pitch, the overall moving time becomes longer, making it difficult to speed up development.

On the other hand, as another example of the movable developing unit system, there is a system in which a plurality of developing units are rotated and moved. In this system, as described above, even when moving from black to magenta, the moving time is 10,000 minutes, and the above-mentioned problem does not occur. However, if the rotational movement method is used, it becomes difficult to replenish toner to the developing device at each position, and since the developing device rotates endlessly, the electrical contacts and the like become extremely complicated. Further, there is a problem in that the developing device may be turned upside down, and countermeasures must be taken to prevent this.

An object of the present invention is to shorten the moving time of the developing units in a system in which a plurality of developing units are arranged side by side in one direction, to speed up image formation, and to reduce the load on the moving motor. It is an object of the present invention to provide a developing device for a color image forming apparatus that can reduce the size of the motor and reduce the size of the motor.

[Means to solve the problem]

The developing device according to the present invention is used in a color image forming apparatus for forming a color image of a document on recording paper.

The n developing devices 2x (n: an integer equal to or greater than 4) arranged in one direction, a moving mechanism for reciprocating the n developing devices, and a movement order of the n developing devices are controlled. and a movement control means for controlling the n developing devices.
The developing devices are arranged so that the amount of movement of each developing device is a maximum of (n-2) pitches.

[Operation] In the present invention, the n developing devices arranged in one direction are moved back and forth with the movement order thereof being controlled by the movement control means. At this time, the n developing devices are arranged so that the amount of movement is the maximum (n-2) pitch, so when moving from the developing device at one end to the developing device at the other end as in the conventional system, The travel time is shortened compared to the travel time of , and it is possible to speed up image formation.

〔Example〕

FIG. 1 is a schematic sectional view of a color copying machine employing a developing device according to an embodiment of the present invention.

In FIG. 1, a document table 2 on which a document is placed is disposed at the top of a copying machine main body l, and a document presser 3 is provided on the top surface of the document table 3 so as to be openable and closable.

Further, a paper discharge tray 4 and a plurality of paper feed force sets 5 are arranged on the left side of the copying machine main body l- in the figure.

Furthermore, a tray 6 for bypass paper feeding is arranged on the right side of the figure.

A photosensitive drum 7 is arranged inside the copying machine main body l. Around the photoreceptor drum 7, in addition to a charging device, a transfer device, a paper separation device, and a cleaning device, developing devices 10, 11, 12, and 13 are arranged vertically side by side.
A developing device 8 is provided. The arrangement of each developer is, from above, cyan developer 10, magenta developer 11.
．． A yellow developing device 12 and a black developing device 13 are provided.

These developing units 10 to 13 are fixed to a movable frame 9, and the movable frame 9 is movable in the vertical direction by a moving mechanism 16. A light shielding plate 14 is fixed to the outer wall of the movable frame 9 for detecting the home position of the developing device 8 and correcting the position. When the developing device 8 is at the home position, the light shielding plate 14 shields the photointerrupter 15 for position correction so that a detection signal is output.

The moving mechanism 116 of the developing device t8 includes a stepping motor (corresponding to the motor 44 for moving the developing Vt position in FIG. 2), a bevel gear 17 connected to the stepping motor, and a bevel gear 18 meshing with the bevel gear 17. , bevel gear 1
A transfer drum 2l is disposed below the photosensitive drum 7 of the device, which is composed of a ball screw 19 fixed to the movable frame 9 and extending in the vertical direction, and a nut 20 fixed to the movable frame 9 and screwed into the ball screw 19. has been done. Further, a laser unit 22 is arranged above the photoreceptor drum. The laser beam from the laser unit 22 is irradiated onto the upper end surface of the photosensitive drum 7. On the other hand, below the document table 2, a reader 23 equipped with a CCD element is arranged. The reader 23 is driven in the left-right direction in FIG. 1, and is capable of scanning a document placed on a document table 212. Reader 2
The image information obtained in step 3 is sent to the laser unit 22 as an electrical signal.

Between the lower part of the transfer drum 2l and the paper feed force set 5 and the bypass paper feed tray 6, there are paper feed conveyance devices 24.
25 are placed. Each paper feed conveyance device ff24.25
The transfer drum 2 is located between the transfer drum 2l, which is composed of a paper feed guide and a plurality of paper feed rollers, and the paper discharge tray 4.
A paper feed conveyance device 26 and an image fixing device 27 are arranged in order from 1111.

As shown in FIG. 2, this copying machine uses a CPU.

It has a control section 40 consisting of a microcomputer equipped with RAM, ROM, etc. The control unit 40 includes an operation panel 41 arranged on the upper end surface of the copying machine, a transfer drum 2l,
a transfer end sensor 42 that detects the rotation of the image sensor to detect the completion of development and transfer of each color; and a photo interrupter 1.
5 and other input sections are connected. The control unit 40 also includes a motor 44 for driving the moving mechanism 16 of the developing device [8, a reader drive mechanism 45 for driving the reader 23 to read the image of the document, and a laser unit 22. Laser ll for laser beam control provided inside
The W unit 46 and other output sections are connected.

Next, the operation will be explained according to the control flowcharts shown in FIGS. 3A to 3C.

When the main switch of the copying machine is turned on, initial settings such as setting the number of copies to one and setting the developing color to black are made in step Sl in FIG. 3A. Further, in this initial setting, the developing device 8 is placed at a home position as shown in FIG. 4A. Detection of this home position is performed using a light shielding plate l4 and a photointerrupter l5.
Using this position as the initial position, the following movement control of the developing unit is performed. Next, in step S2, it is determined whether the print key on the operation panel 4l has been pressed. Further, in step S3, it is determined whether the full color key has been pressed, and in step S4, it is determined whether or not any other key has been pressed.

Here, if the full color key is pressed, the program moves from step S3 to step S6. In step S6, it is determined whether the full color flag is in the on state. If the full color flag is off,
After proceeding to step S7 and turning on the full color flag, the process returns to step S2. If it is determined in step S6 that the full color flag is in the on state, the full color flag is turned off in step S8, and then the process returns to step S2.

Suppose that the full color copy mode is specified (the full color flag is on (1!)) and the print key is pressed. Then, YES is determined in step S2, and the process moves to step S9 in FIG. 3B. In step S9,
A predetermined recording paper is fed from the paper feed power set 5. The fed recording paper is fed by a paper feed conveyance device 24.

Next, in step SIO, it is determined whether the full color flag is on. In this example, the full color flag is in the on state, so the process moves to step Sll. In step Stt, as shown in FIG. 48, the magenta developing device 11 is moved to the developing position.

This movement control is performed by controlling the rotation angle of the stevening motor 44 by the iJJm section 40.

Note that in steps St and t, the CC of the reader 23
The filter provided above D is also switched, and the magenta filter is positioned above the CCD.

In this state, the process moves to step S12 and an image forming operation subroutine is executed.

In the image forming operation subroutine, as shown in FIG. 3C, first, in steps S2, the image is read and a latent image is formed on the photosensitive drum 7, and then, in step S23, the image is developed by the magenta developing device 11. Formation is performed, and then the process moves to step S24 to perform the transfer onto the recording paper on the transfer drum 211, after which the process returns to the main routine shown in FIG. 3B.

When the development of the magenta color is completed, this is detected by the transfer end sensor 42, and the process moves to step 513. In step 313, as shown in FIG. 4C, the cyan developer IO is controlled to move to the developing position. Then, in step S14, an image forming operation subroutine similar to that described above is performed using the cyan developer lO.
2, yellow development is performed, and black development device 13 performs black development, and the images are transferred onto the recording paper of two transfer drums.

When the black development is completed, the process moves to step S20, where a conventional fixing operation is performed, and at step S21, a paper ejecting operation is performed, and the process returns to step S2 in FIG. 3A. Note that filter switching control is also performed simultaneously with the movement control of each developing unit.

The recording paper on which full-color copies have been made in this manner is obtained on the paper discharge tray 41:.

Next, if the black-and-white copy mode is designated (if the full-color flag is off), the determination in step SIG is NO, and the process moves to step S19. In step S19, an image forming operation using normal black-and-white development and transfer operations is performed. Then, through the processes of step S20 and step S21, transfer paper on which black and white copies have been made is obtained on the wandering paper tray 4.

In this embodiment, when full-color copying is performed,
Development is performed in the order of magenta, cyan, yellow, and black, but at this time, the amount of movement of the developing device is a maximum of 2 pitches, compared to the case of moving 3 pitches as in the case of conventional full color development. This can speed up copying. In addition, the burden on the moving motor is reduced, and the motor can be made smaller and costs can be reduced.

Furthermore, when performing monochrome development of R, G, and B, two developing devices are used, but in this embodiment, even when performing monocolor development, the amount of movement of the developing device is a maximum of 2 pitches. Speed-up can be achieved. That is, when performing monochrome copying using red (R), magenta developer 11 and yellow developer 12 are used; for green (G), cyan developer lO and yellow developer 12 are used; Regarding B), copies are made using the cyan developer 10 and the magenta developer 11, but in these cases as well, the maximum diameter vJ amount is 2 pitches.

[Other Examples]

(8) In the above embodiment, the developing devices were arranged in order from top to bottom: cyan, magenta, yellow, and black, but other arrangements may be possible as shown in FIGS. 5A to 5C. be. Even in the case of such an arrangement, the maximum movement amount can be set to 2 pitches.

(c) In the embodiment shown in FIG. 1 and the embodiment shown in FIGS. 5A to 5C, full color copying and R, G.

Assuming that monochrome copying of B is performed, the developing device is arranged so that the maximum amount of movement is 2 pitches.
If monochrome colors of R, G, and H are not considered, other arrangements are possible.

(C) In the above embodiment, when the full color development order is magenta → cyan → yellow → black, the arrangement is as shown in FIG. 1 and FIGS. 5A to 5C. If the order differs from the above, the arrangement of the developing devices may be set accordingly so that the maximum movement amount is two pitches.

In the above embodiment, the present invention is applied to a device in which four developing devices are arranged in a vertical direction and move up and down, but the present invention is also applicable to a device in which four developing devices are arranged in a horizontal direction and move back and forth. River can.

(6) In the above embodiment, the case where full-color copying is performed using four developing units was explained, but in general, n(
When full-color copying is performed using developing devices (n is an integer of 4 or more), if the developing devices are arranged so that the maximum movement distance is (n-2) pitches, the developing device travel time can be reduced.

〔Effect of the invention〕

As described above, in the present invention, when performing multicolor development, by appropriately setting the arrangement of the developing devices according to the development order,
The moving time of the developing device is shortened, and the speed of image formation can be improved. Furthermore, if the image forming speed is kept the same as before, the motor can be made smaller.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional configuration diagram of a full-color copying machine employing a developing device according to an embodiment of the present invention, FIG. 2 is a control block diagram thereof, FIGS. 3A to 3C are control flowcharts thereof, and FIGS. FIG. 4E is a diagram for explaining the operation of the developing device, FIGS. 5A to 5C are diagrams showing the arrangement of the developing device according to another embodiment of the present invention, and FIG. 6 is a diagram showing a conventional device. . 8... Developing device, 10-13... Developing device, 16...
・Moving mechanism, 17.18...Bevel gear, 19...Ball screw, 2 G-...Ball nut, 40...
-Control unit, 44...Motor for moving the developing device.

Claims (1)

[Claims] (1) A developing device of a color image forming apparatus for forming a color image of a document on recording paper, comprising n (n: an integer of 4 or more) developing devices arranged in one direction; a moving mechanism for reciprocating the n developing devices, and a movement control means for controlling the movement order of the n developing devices, wherein the n developing devices have a maximum movement amount ( n-2
) A developing device of a color image forming apparatus, which is arranged to have a pitch.