JP2000284597A - Color image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a machine body from being soiled due to the spill of toner from a developing device and to prevent a vertical stripe state image defect caused by the accumulation of the toner on a lower seal and a toner regulating blade. SOLUTION: When the development of one color is finished and a developing rotary 22 is rotated in order to shift to the development of a next color, a developing roller driving gear 48 provided in the developing device 24 whose developing operation is finished is meshed with a gear 50 fixedly provided in a main body corresponding to the gear 48, and a developing roller 34 is rotated in the direction shown by an arrow K opposite to the direction in developing by the rotation of the gear 50 in the direction shown by an arrow J. By reversely rotating the roller 34, the toner 28 accumulated between the roller 34 and the lower seal 46 is forcibly scraped at the accumulation position, naturally drops and is accumulated on a toner receiving part 52 provided below the rotary 22. The toner 28 accumulated between the roller 34 and a toner regulating blade 36 is also restored into the developing device 24y.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image forming apparatus, and more particularly to, for example, a developing rotary having a plurality of developing units disposed in the vicinity of a photoreceptor and rotating the developing rotary at the time of development to form an arbitrary color. The present invention relates to a color image forming apparatus in which a developing device is brought to a position facing a photoconductor.

[0002]

2. Description of the Related Art Conventionally, in a color image forming apparatus of this type, toner spilling from a developing unit has been prevented by contacting a lower seal with a developing roller.

[0003]

However, according to the prior art, when the life of the developing device is long, the toner accumulated on the lower seal gradually falls off from the developing device, and the main body of the machine is soiled. Further, if the toner adheres on the lower seal, a vertical streak-like image defect occurs. Further, the toner also accumulates between the developing roller and the toner regulating blade, and even if the toner adheres on the toner regulating blade, a vertical streak-like image defect occurs.

SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to provide a color image forming apparatus capable of preventing contamination due to toner spilling from a developing device and eliminating an image defect caused by accumulation of toner. .

[0005]

SUMMARY OF THE INVENTION The present invention relates to a photosensitive member, a developing rotary rotatably supported in the vicinity of the photosensitive member and having a plurality of developing units, a developing roller individually provided for each of the plurality of developing units, A toner regulating means provided in association with each developing roller, and a lower seal in contact with the developing roller are provided. By rotating the developing rotary during development, a developing device of an arbitrary color is brought to a predetermined position facing the photosensitive member. In the above-described color image forming apparatus, by rotating the developing roller in a direction opposite to that during development at the time of suspension, the toner accumulated between the developing roller and the lower seal is scraped off, and the developing roller and the toner regulating blade are removed. A color image forming apparatus characterized by scraping off toner accumulated between the two.

[0006]

The developing rotary is provided with a plurality of developing devices having different colors to be developed. Each of the plurality of developing devices is provided with a developing roller and a lower seal that contacts the developing roller. The lower seal closes a gap between the developing roller and the developing device, and prevents toner from spilling from the developing device.

When the development rotary is rotated to complete the development of one color and to proceed to the development of the next color, for example, the developing roller driving gear of the developing device for which the developing operation has been completed and the developing roller driving gear correspond to the developing roller driving gear. The fixedly provided gear unit meshes with the developing unit, and rotates the developing roller of the developing unit in which the developing operation has been completed in a direction opposite to that in the developing operation. Due to the reversal of the developing roller, the toner accumulated between the developing roller and the lower seal is forcibly scraped off at that position, falls naturally, and accumulates on a toner receiving portion provided below the developing rotary. Also, by inverting the developing roller,
The toner accumulated between the developing roller and the toner regulating blade is also scraped off and returned to the developing device.

[0008]

According to the present invention, the toner accumulated between the developing roller and the lower seal can be scraped off at the end of the developing operation of each developing device. Will not be stained. Also,
Vertical streak-like image defects due to accumulation of toner on the lower seal are eliminated.

Further, since the toner accumulated between the developing roller and the toner regulating blade can be returned to the inside of the developing device, a vertical streak-like image defect due to the accumulation of the toner on the toner regulating blade is eliminated. .

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A color image forming apparatus 10 of this embodiment shown in FIG. 1 includes a photoreceptor unit 12 which is detachably mounted substantially at the center of an apparatus main body. The photosensitive drum 14 is rotated in the direction of arrow A by a driving mechanism (not shown). A charging device 16 is provided diagonally above and to the left of the photosensitive drum 14 in the photoconductor unit 12, and the surface of the photosensitive drum 12 is uniformly charged by the charging device 16. An exposure device (not shown) is provided above the photosensitive drum 14, and an electrostatic latent image is formed on the charged surface of the photosensitive drum 14 by the exposure device. Further, a cleaning blade 18 is provided so as to be in contact with the surface of the photosensitive drum 14, and the toner remaining on the surface of the photosensitive drum 14 after transfer described later is scraped off by the blade 18 and collected in the waste toner box 20.

The developing rotary 2 is located on the right side of the photosensitive drum 14.
The developing rotary 22 includes a four-color developing device 2.
4y, 24m, 24c and 24b are arranged in the rotation direction. For example, the developing device 24y is for developing yellow (Y), the developing device 24m is for developing magenta (M), the developing device 24c is for developing cyan (C),
The developing device 24b is for developing black (Bk). These developing units 24y, 24m, 24c and 24b have a rotation angle 9 obtained by dividing the rotation angle 360 degrees of the development rotary 22 into four.
Each is arranged in a range of 0 degrees.

The developing rotary 22 is rotatably provided in a direction indicated by an arrow B by a rotating shaft (not shown). When a developing color is designated by a computer (not shown), the developing units 24y, 24m, 24c or 24b of the colors are exposed to light. The developing rotary 22 is rotated so as to stop at a predetermined position facing the drum 14 or at a developing position.

Developing units 24y, 24m, 24c and 24
The structure b will be described using the developing device 24y as an example. The developing device 24y includes a toner box 26 in which the toner 28 is stored. The toner box 26 is provided so as to be displaceable in a direction parallel to a line passing through the center of the developing rotary 22, and is elastically attached outward in the above direction by a spring 30 disposed between the toner box 26 and an adjacent toner box 26. And the toner box 26 is constantly pressed outward. In the toner box 26, the toner 2
The supply roller 32 is provided so as to contact the supply roller 8, and the supply roller 32 is rotated in the direction of arrow C.

A developing roller 34 is provided below the opening of the toner box 26 so as to contact the supply roller 32.
This developing roller 34 is rotated in the direction of arrow D. Therefore, the toner 28 in the toner box 26 is transported to the developing roller 34 via the supply roller 32.

Above the opening of the toner box 26 of the developing unit 24y, a toner regulating blade 36 as a toner regulating means is provided. The toner regulating blade 36 is formed of, for example, a flat plate made of metal such as stainless steel or plastic, and has a shaft 38
Supported by The blade supporting member 40 is made of, for example, plastic or metal, and is rotatable on the shaft 38 in the direction of arrow E or F. Therefore, the toner regulating blade 36 rotates in the direction of arrow G or H.

In order to rotate the toner regulating blade 36, a projection 42 is formed on the photosensitive unit 12 described above. The projection 42 functions as an action portion acting on the toner regulating blade 36. That is, the developing devices 24y, 24m, 24 brought to the developing position or a predetermined position by the rotation of the developing rotary 22 for developing the color.
The blade supporting member 40 of c or 24b hits the protrusion 42 and is pushed in the direction of arrow E. Accordingly, the toner regulating blade 36 rotates in the direction of arrow H.

When the blade supporting member 40 rotates in the direction of arrow E and the toner regulating blade 36 rotates in the direction of arrow H, the tip of the toner regulating blade 36 is pressed against the surface of the developing roller 34. Therefore, the toner adhered to the surface of the developing roller 34 is charged to a predetermined polarity by friction with the toner regulating blade 36 and adheres to an electrostatic latent image of a predetermined polarity on the surface of the photosensitive drum 14, whereby The image is developed with toner.

A transfer roller 44 having a surface in contact with the surface of the photosensitive drum 14 is provided below the photosensitive unit 12, and a transfer material, that is, a sheet (not shown) is wound around the transfer roller 44. By the contact between the photosensitive drum 14 and the transfer roller 44, the toner image formed on the photosensitive drum 14 is transferred to the transfer material. When the transfer of the toner image of one color is completed, the transfer roller 44, that is, the transfer material or the paper makes one rotation in the direction of arrow I to prepare for the next transfer. Then, each time the transfer roller 44 is rotated once, the developing rotary 22 is rotated, and the electrostatic latent images are sequentially developed by developing devices of different colors.

When the developing device 24y completes the developing operation, the toner 28 on the developing roller 34 that has not been used for the development passes through the lower seal 46, is returned to the toner box 26, and is scraped off by the supply roller 32. . Lower seal 4
6 is installed near the opening of the toner box 26 and comes into contact with the developing device 24y so that the toner box 26
Block the gap between the toner box 26 and the developing roller 34.
To prevent the toner from spilling from.

When the development process for one color is completed, the development rotary 22 develops the next color.
The developing device for the next color is rotated so as to move to a developing position facing the photosensitive drum 14 or to a predetermined position. By this rotation, the development is completed, for example, the yellow developing device 24
In y, as shown in FIG. 2, the pressing force of the protrusion 42 of the photoconductor unit 12 against the blade supporting member 40 is released. Accordingly, the pressing force against the toner regulating blade 36 is released, and the elasticity or spring pressure of the toner regulating blade 36 causes the toner regulating blade 36 to rotate about the shaft 38 in the direction of arrow G, and the toner regulating blade 36 It is in a state away from.

When the developing rotary 22 rotates, the developing roller driving gear 48 provided in the yellow developing unit 24y meshes with a gear 50 fixed to the main body so as to correspond to the developing roller driving gear 48, and the gear 50 The developing roller 34 is rotated in the direction of arrow K in the direction opposite to the direction during development by the rotation in the direction of arrow J. Due to the reversal of the developing roller 34, the toner 28 accumulated between the developing roller 34 and the lower seal 46 is forcibly scraped off at that position, falls naturally, and falls to a toner receiving portion provided below the developing rotary 22. 52. Further, the toner 28 accumulated between the developing roller 34 and the toner regulating blade 36 is also scraped off by the reversal of the developing roller 34 and returned to the developing device 24y.

Therefore, in this embodiment, each developing unit 2
At the end of the developing operation of 4y, 24m, 24c and 24b, the toner 28 accumulated on the lower seal 46 and the toner regulating blade 36 is scraped off, so that the toner 28 does not spill from the developing units 24y to 24b and does not stain the machine body. . In addition, a vertical streak-like image defect due to accumulation of the toner 28 on the lower seal 46 and the toner regulating blade 36 is eliminated, and a good image can be obtained for a long period of time.

[Brief description of the drawings]

FIG. 1 is an illustrative view showing one embodiment of the present invention;

FIG. 2 is an illustrative view showing rotation of a developing rotary of the color image forming apparatus shown in FIG. 1 embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Color image forming apparatus 12 ... Photoconductor unit 14 ... Photosensitive drum 22 ... Developing rotary 24y, 24m, 24c, 24b ... Developing device 34 ... Developing roller 36 ... Toner regulating blade 46 ... Lower seal 48 ... Developing roller drive gear 50 ... Gear 52: toner receiving portion

Claims (3)

[Claims] A photoreceptor, a developing rotary rotatably supported in the vicinity of the photoreceptor and having a plurality of developing units, a developing roller individually provided for each of the plurality of developing units,
A toner regulating unit provided in association with each of the developing rollers, and a lower seal in contact with the developing roller, wherein a developing device of an arbitrary color is opposed to the photoconductor by rotating the developing rotary during development. In the color image forming apparatus, which is brought to a predetermined position, by rotating the developing roller in a direction opposite to that during development at the time of rest, the toner accumulated between the developing roller and the lower seal is scraped off and Wherein the toner accumulated between the developing roller and the toner regulating blade is scraped off. 2. A color image forming apparatus according to claim 1, further comprising a toner receiving portion provided below said developing rotary and receiving the scraped toner. 3. The apparatus according to claim 1, further comprising a first gear, and a second gear provided on said developing roller and meshing with said first gear, wherein said developing roller is rotated by said first gear and said second gear. Or the color image forming apparatus according to 2.