JPH049080A - Developing device - Google Patents

Abstract

PURPOSE:To prevent the flow-out of scratched off toner at a projecting part by providing a projecting part for preventing the flow-out of the toner on a casing, outside compared with the abutting position of a developing roller and a blade. CONSTITUTION:The blade 43 to form a toner thin layer abuts on the developing roller 42 in the counter direction of the rotation of the developing roller 42, at a position 28, and the projecting part A is provided on the casing 22, at the position which is slightly near to the side of the curved point 43 of the blade compared with the abutting position 28, that is, outside compared with the position of the belt-like photosensitive body. The toner placed on the developing roller 42 is made into a prescribed thin layer at the abutting position 28 of the blade 43, and separated to the toner of the thin layer left on the developing roller 42 and the scratched off toner. The scratched off toner does not flow outside, by obstructing the projecting part A. Thus, the projection can prevent from the flowing of the toner outside this developing device 14.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a developing roller for visualizing a latent image on a photoreceptor, and a method for forming a thin toner layer that contacts the developing roller in a counter direction with respect to its rotation. The present invention relates to a developing device for an image forming apparatus, which includes a blade for use in the image forming apparatus, and a casing in which the developing roller, the blade, and the like are disposed.

[Conventional technology]

The above-mentioned developing device is used in image forming apparatuses such as copying machines and laser printers. A toner hopper, a developing roller, a blade for forming a thin toner layer on the developing roller, and the like are arranged within the casing of the developing device. If Play 1 is placed on the toner hopper side of the developing roller,
The contact pressure and the like are easily affected by toner, so the blade is arranged so that its image point is on the outside. At this time, the toner scraped off at the contact position between the blade and the peripheral surface of the developing roller tends to flow outward.

This has the disadvantage of causing contamination within the image forming apparatus and wasteful consumption of toner.

[Problem to be solved by the invention]

An object of the present invention is to eliminate the above-mentioned disadvantages in the developing device of a conventional image forming apparatus.

[Means to solve the problem]

The above problems can be solved by the present invention.
This can be solved by providing the casing with a protrusion for preventing toner outflow outside the position of contact with the casing.

Furthermore, in order to solve the above problem more conveniently, the present invention proposes, in addition to the above-mentioned means, to provide a toner holding space further outside the toner outflow prevention protrusion.

〔Example〕

In the laser printer shown in FIG.
0 consists of an earth structure 10a and a lower structure 10b, and the earth structure 10a is attached to the lower structure 10b by a shaft 11 so as to be openable and closable. Inside the apparatus main body 10, a belt-shaped photoreceptor 12 is arranged at the center so as to rotate in the direction of the arrow.

Around the photoreceptor 12, electrophotographic processing means such as a charging device 13, a developing device 14, a transfer device 15, and a cleaning device 16 are arranged in order in the direction of rotation shown by the arrow. A paper feed cassette 19 is placed above these electrophotographic processing means, and an optical writing device 18 is placed below. The paper fed from the paper feed cassette 19 by the paper feed roller 2o is conveyed to the upper side of the photoreceptor 12 with timing determined by the pair of registration rollers 21. When the photoreceptor 12 rotates in the direction shown by the arrow, the charging device 1
3, the surface is uniformly charged by the optical writing device 18.
An electrostatic latent image is formed on the photoreceptor 12 by being irradiated with laser light from the photoreceptor 12 . This latent image becomes visible when it passes through the developing device 14. This visible image is then transferred by the transfer device 15 to the lower surface of the sheet of paper that has been conveyed above the photoreceptor 12 .

The thus transferred paper is guided by the conveyance guide 23 and conveyed between the fixing roller 17a and the pressure roller 17b of the fixing device 17, and the visible image is fixed thereon.

The paper that has left the fixing device 17 is further conveyed to a paper discharge section 25 by a paper discharge roller 24, guided by a paper discharge guide 26, and stacked on a paper discharge I-ray 27.

The optical writing device 18 is arranged below the base cover 29 of the main body 1o of the device. The base cover 29 is disposed at the bottom of the device main body 10, and is formed integrally or separately from a pair of opposing side covers by connecting them. The base cover 29 is made of a heat insulating thermosetting resin, etc.
Legs 30.30 are provided in parallel on both sides. Its legs 30.
A flat plate part 31 connecting the parts 30 is provided with a bulge part 32 that projects upward. Inside the bulge 32, as shown in the figure, a space 33 that opens downward is provided.

In addition, the bulging portion 32 has a space 33 in the direction of the leg portion 30 and 30.
A long slit-shaped window hole 34 is provided.

In the space 33 of the base cover 29, an optical writing device 1 is provided.
Eight different components are attached directly to the base cover 29 itself. i.e. in fig.

36 is a scanner motor, 37 is a polygon mirror 38 is f
39 is a second mirror, and 4o is a cylinder lens attached to the casing 22 of the developing device 14.

The light that flashes in response to the image information signal emitted from the laser unit is incident on a polygon mirror 37 that is integrally attached to the shaft of the scanner motor 36, and is repeatedly deflected into polygons within a certain angular range. The polarized light is imaged on a straight line by the fθ lens 38 at the optical writing position on the photoreceptor 12, corrected so that the projection point moves at a constant speed, and then passed through the second mirror 39 and the cylinder lens 40. , is incident on the photoreceptor 12, as shown in FIG. Then, main scanning is performed by deflecting the incident light, sub-scanning is performed by rotating the photoreceptor 12, and an image according to the image information signal is written.
An electrostatic latent image is formed.

The downward opening of the space 33 in which the optical writing device 18 is attached is covered with a cover plate 41.

A developing roller 42 is located inside the casing 22 of the developing device 14.
and a supply member 44 are rotatably mounted. Furthermore, a toner hopper 48 is provided in the casing 22,
An agitator 47 is installed inside this and supplies toner to the replenishing member 44 and further to the developing roller 42. 43 is l
This is a blade for forming one to four thin layers that comes into contact with the VVO2 roller 42 in a counter direction with respect to its rotation. This blade is attached to the casing 22, and 43a is its white point.

In FIG. 2, a blade 43 for forming a thin layer of toner is brought into contact with the developing roller 42 at a position 28 counter to its rotation. A protrusion A is provided on the casing 22 slightly closer to the white point 43a of the blade than the contact position 28, that is, on the outside where the belt-shaped photoreceptor is located. Furthermore, a toner holding space B is arranged outside this protrusion A.

In Figure 3, the toner on the developing roller 42 is
The toner is formed into a predetermined thin layer at the contact position 28 of the blade 43, and is divided into the thin layer of toner remaining on the developing roller 42 and the toner that is scraped off. The toner that is scraped off is blocked by the protrusion A and does not flow outside. Even if some toner flows out, such toner is retained in the toner holding space B and is prevented from flowing out any further. Further, by providing the toner holding space B, the toner 43 will not be affected by the 1 hener deposited on the play 1, and the contact pressure between the plays 1 and 2 will no longer fluctuate.

〔Effect of the invention〕

The present invention prevents toner from flowing out of the developing device, eliminates dirt in the image device and wasteful consumption of toner, and prevents fluctuations in blade contact pressure to maintain a stable toner thin layer. guaranteed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a laser printer equipped with a developing device constructed according to the present invention, FIG. 2 is an enlarged sectional view of the developing device, and FIG. 3 is a functional explanatory diagram of the protrusion and toner holding space according to the present invention. be. 12. Belt-shaped photoreceptor 22 Casing 28... Contact position 42 - Developing roller 43... Blade A - Projection

Claims (2)

[Claims] (1) A developing roller for visualizing the latent image on the photoreceptor, a blade for forming a thin layer of toner that contacts the developing roller in a counter direction with respect to its rotation, and the developing roller, blade, etc. inside the developing roller. 1. A developing device for an image forming apparatus comprising: a casing for disposing a toner outflow prevention protrusion on the casing outside a contact position between a developing roller and a blade. (2) The developing device according to claim 1, further comprising a toner holding space provided outside the toner outflow prevention protrusion.