JPH04247475A - Color electrophotographic copying device - Google Patents

Abstract

PURPOSE:To reduce the cost of the device and to eliminate such a malfunction that plural developing devices are simultaneously closely brought into contact with a photosensitive body by simplifying structure for bringing the developing device into contact with the photosensitive body or retreating from it so that the device is easily assembled. CONSTITUTION:A carrying means 34, a second energizing member 35 which is provided on the carrying means 34 and a pressing member 36 which is supported by the carrying means 34 through the energizing member 35 and moved by the carrying means 34 and which pushes out the selected developing devices 13a, 13b, 13c and 13d to the photosensitive body 10 side by the energizing member 35 by resisting to a first energizing member 38 are provided. Then, developing is executed by moving the pressing member 36 by the carrying means 34 and pushing out the properly selected developing devices 13a, 13b, 13c and 13d to the photosensitive body 10 side by the second energizing member 35 by resisting to the first energizing member 38.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention is applicable to printers, copiers, facsimile machines, etc. using laser electrophotography (a method of recording by transferring an image formed on a photoreceptor onto paper).
This method can be applied to electrophotographic devices that record on paper. Specifically, a plurality of developing devices are arranged along the surface of the photoreceptor, each supported so as to be able to move toward and retract from the surface of the photoreceptor, and is normally maintained at a retracted position by being biased by a first biasing member;
The present invention relates to a color electrophotographic apparatus that selectively pushes one of them toward the photoreceptor.

0002

[Prior Art] Conventionally, in this type of color electrophotographic apparatus, a plurality of developing devices are used to develop each color on a photoreceptor, and after overlapping the images of each color, the images are transferred to paper. A color image is obtained by doing this. At this time, the developing devices that do not perform development are separated from the surface of the photoreceptor to avoid color mixing, and as shown in FIG. A protruding cam 3 is provided on the rear side of each developing device 1 to move toward and away from the photoreceptor 4.

0003

However, the color electrophotographic apparatus described above requires the same number of projecting cams 3 as the developing units 1, each of which is driven separately, making the structure complicated. For this reason, assembly of the apparatus is troublesome and costs increase, and a plurality of developing devices 1 are simultaneously installed on the photoreceptor 4.
There were problems such as the risk of malfunctions approaching the

[0004] Therefore, the present invention simplifies the structure for moving the developing device close to the photoreceptor, thereby simplifying the assembly of the device and reducing costs. The purpose is to eliminate malfunctions that are close to each other at the same time.

[0005]

[Means for Solving the Problems] Therefore, the present invention as set forth in claim 1 provides a method for connecting a plurality of developing devices 13a, 13b, 13c, and 13d to a photoreceptor, for example, as in the illustrated embodiment below.
They are arranged along the surface of the photoreceptor 10 and supported so as to be able to move toward and away from the surface of the photoreceptor 10, and are normally held at the retracted position by being biased by the first biasing member 38, and one of them is selected as appropriate. In a color electrophotographic apparatus in which the photoreceptor 10 is pushed forward, the conveyance means 34 , a second biasing member 35 provided on the conveyance means 34 , and a second biasing member 35 provided on the conveyance means 34 , and the conveyance means The developing devices 13a, 13b, 13c, and 1 selected by being supported by the conveying means 34 and moved by the conveying means 34
3d against the first biasing member 38 and the second biasing member 38.
A pressing member 36 that pushes out toward the photoreceptor 10 side with a biasing member 35 of
It is characterized by having the following.

[0006] Further, the present invention as set forth in claim 2 is, for example, as shown in the following illustrated embodiment, in the invention as set forth in claim 1, the first biasing member 38 and the second biasing member It is characterized in that each of the 35 biasing forces can be adjusted.

[0007] Further, the present invention as set forth in claim 3 is, for example, as in the illustrated embodiment below, in the invention as set forth in claim 1, the conveying means 34 includes a rotor rotatably driven by a motor. The present invention is characterized in that it is provided with a wire 31, a wire 32 extending therethrough, and a moving plate 33 that is supported by the wire 32 and supports the pressing member 36 via the second biasing member 35. .

[0008] Furthermore, the present invention as set forth in claim 4 is such that, in the invention set forth in claim 3, for example, as in the illustrated embodiment below, in the invention as set forth in claim 3, the backing 37 of the moving plate 33 is It is characterized by having the following.

[0009]

[Function] In the invention described in claim 1, the pressing member 36 is moved by the conveying means 34, and the developing units 13a, 13b, 13 are selectively moved against the urging force of the first urging member 38.
c and 13d are pushed out toward the photoreceptor 10 by the second urging member 35 and developed.

In the invention as set forth in claim 2, the biasing force of the first biasing member 38 or the second biasing member 35 is adjusted so that the developing units 13a, 13b, 13c, and 13d and the photoreceptor 10 Determine the position when and are close to each other.

Further, in the invention described in claim 3, the roller 31 is rotated by driving the motor, and the moving plate 3 is moved by the wire 32.
Move 3. Then, the pressing member 36 is pressed against the rear surface of the developing devices 13a, 13b, 13c, and 13d by the second urging member 35, and the developing devices 13a, 13b, 13c are pressed against the urging force of the first urging member 38. - 13d is pushed out to the photoreceptor 10 side and developed.

Furthermore, in the fourth aspect of the invention, the movable plate 33 is supported by the backing 37 to ensure that the pressing member 36 pushes out the developing devices 13a, 13b, 13c, and 13d toward the photoreceptor 10. .

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 shows a color display according to an embodiment of the present invention.
This figure shows a schematic configuration of the vicinity of a photoreceptor of a laser printer. Reference numeral 10 in the figure is a photoreceptor. Around the photoreceptor 10, in a clockwise direction, a charger 11, an optical writer 12,
Developing units 13a, 13b, and 13c for each color of yellow, red, blue, and black
- 13d, transfer charger 14, static eliminator 15, and cleaning device 16 are arranged.

The photoreceptor 10 is rotationally driven in the direction of the arrow,
At that time, after charging the surface of the photoreceptor 10 with the charger 11,
An optical writer 12 provided at the top irradiates a laser beam with a yellow image signal, for example, to form an electrostatic latent image on the photoreceptor 10. Then, this electrostatic latent image is transferred to a yellow developing device 13a.
A yellow toner image is formed on the photoreceptor 10. During this time, the developing units 13b and 1 for each color of red, blue, and black other than yellow
3c and 13d are retracted from the photoreceptor 10. After development with yellow toner, the surface of the photoreceptor 10 is neutralized by a static eliminator 15. Next, charging, exposure, development, and static elimination are repeated in the same manner as in the formation of the yellow toner image, and the red developing device 13b
, a blue developing device 13c, and a black developing device 13d form respective toner images. After all toner development is completed, the toner is electrostatically transferred onto the paper 17 which is conveyed to the lower side of the photoreceptor 10 by the transfer charger 14. On the other hand, the toner remaining on the photoconductor 10 after electrostatic transfer is removed by a cleaning device 1.
Remove with 6.

By the way, as shown in FIG.
3a, 13b, 13c, and 13d are provided with two upper and lower rollers 30 and 31 as shown in FIG.
A wire 32 is passed between 0 and 31. Also, one of the rows
The gear 28 is driven by a motor (not shown) in the gear 31.
- Transmit rotation via 29. Then, the wire 3
A moving plate 33 is attached to each developing device 1.
3a, 13b, 13c, and 13d. In addition, on the moving plate 33,
For example, a second biasing member 35 made of a spring or the like is attached to each developing device 1.
3a, 13b, 13c, and 13d, and a pressing member 36 with a rounded tip is attached to the tip of this biasing member 35, and the pressing member 36 is attached to the developing device 13a, 13.
Press it against the rear surface of one of b, 13c, and 13d. on the other hand,
On the rear side of the moving plate 33, that is, on the opposite side from the photoreceptor 10,
A backing member 37 is provided over the movement range, and a first biasing member 38 made of, for example, a coil spring is attached to the backing member 37.
is attached to each of the developing devices 13a, 13b, 13c, and 13d to urge the developing devices 13a, 13b, 13c, and 13d backward. At all times, each developing device 13a, 13b,
13c and 13d are set at retracted positions with respect to the photoreceptor 10.

Then, by driving the motor, the gears 28 and 29 are
The rollers 30 and 31 of the conveying means 34 are rotated via the wire 32, and the moving plate 33 is moved to the position of the developing device 13a for yellow, for example, where development is required. Then, the pressing member 3
6 pushes out the developing device 13a by the urging force of the second urging member 35 against the urging force of the first urging member 38, and the developing device 13a approaches the photoreceptor 10. Other developing devices 13
In the same manner, the photoreceptors b, 13c, and 13d are selectively pushed out and brought close to the photoreceptor 10. Then, development is performed as described above.

Furthermore, each developing device 13a, 13b, 13c,
The distance between the first biasing member 38 and the second biasing member 3 is adjusted by adjusting means (not shown).
Adjust the biasing force of either or both of steps 5 and 5.

[0019]

Accordingly, the present invention simplifies the structure for moving the developing device close to the photoreceptor, making it easier to assemble the device, reducing the cost of the device, and allowing multiple developing devices to move closer to the photoreceptor. It is possible to eliminate malfunctions that occur in close proximity to the body at the same time.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the vicinity of a photoreceptor and a developing device of a color laser printer that is an embodiment of the present invention.

FIG. 2 is a perspective view showing a conveying means and a backing provided on the rear side of the developing device.

FIG. 3 is a schematic diagram showing the vicinity of the photoreceptor of the color laser printer.

FIG. 4 is a schematic configuration diagram of the vicinity of a photoreceptor and a developing device in a conventional example.

[Explanation of symbols]

10 Photoreceptor 13a Yellow developer 13b Red developer 13c Blue developer 13d Black developer 30/31 Laura 32 Wire 33 Moving board 34 Transport means 35 Second biasing member 36 Pressing member 37 Backing 38 First biasing member

Claims (4)

[Claims] Claim 1: A plurality of developing devices are arranged along the surface of a photoreceptor and each supported so as to be movable toward or retracted from the surface of the photoreceptor,
In a color electrophotographic apparatus that is biased by a first biasing member to maintain the retracted position at all times and selectively pushes one of the biasing members toward the photoreceptor side as appropriate, the color electrophotographic apparatus includes a conveying means and a conveying means provided therein. a second biasing member; the developer is supported by the conveying means via the second biasing member, and is moved by the conveying means to push the selected developing device against the first biasing member; A color electrophotographic apparatus comprising a pressing member that pushes out toward a photoreceptor by a second urging member. 2. The color electrophotographic apparatus according to claim 1, wherein the biasing forces of the first biasing member and the second biasing member are adjustable. 3. The conveying means includes a roller rotatably driven by a motor, a wire that is stretched around the roller, and the pressing member is supported by the wire and supported via the second urging member. 2. The color electrophotographic apparatus according to claim 1, further comprising a moving plate. 4. The color electrophotographic apparatus according to claim 3, further comprising a backing for the movable plate over a range of movement of the movable plate.