JPH01297686A - Developing device - Google Patents

Abstract

PURPOSE:To reduce the quantity of toner applied on both ends of a developing roller and to simplify the seals of both end parts of the developing roller by making the width of a developer supplying member smaller than that of the sandblast of the developing roller. CONSTITUTION:The width L2 of the developer supplying member 8 is made smaller than the width L3 of the sandblast of the developing roller 7 and equal to that of an opening part 14. Therefore, a conveying force for developer 6 which is conveyed to both end parts in the longitudinal direction of the developing roller 7 is extremely weakened. Thus, the quantity of the toner applied on both ends of the developing roller 7 is reduced and the quantity of the toner passing on the developing roller 7 through to both ends is decreased, whereas the seals of both and parts of the developing roller 7 can be simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a developing device for developing an electrostatic latent image formed on a latent image carrier into a visible image in electrophotography.

Conventional technology Conventionally, development methods using dry developers can be roughly divided into two types.
There are two types of methods: methods using component-based developers and methods using single-component developers.

Since the method using a two-component developer uses a mixed developer of toner and carrier, it requires a toner concentration control device to maintain a constant mixing ratio of toner and carrier, and also requires periodic replacement due to a decrease in chiaria. It has the disadvantage of being. Therefore, recently, in order to eliminate the above-mentioned drawbacks, a developing method using only a one-component developer without using a carrier has been proposed.

In the developing method using this one-component developer, spillage of the developer becomes a problem. In particular, the largest amount of developer spills from the gap between the developer carrier and the bottom plate of the housing.

To solve the above problem of developer spillage, it has been proposed in the conventional developing device to provide a developer spillage prevention means under the developing roller. FIG. 3 shows a conventional developing device. In FIG. 3, 34 is a developing roller, 44 is a coating blade, 35 is a fur brush, and 38 is a scraping plate. Below the developing roller 34, there is provided developer spill prevention means consisting of a developer leak prevention member 51 and a developer leak prevention sheet 52. Developer leak prevention member 5
1 is attached so as to be in contact with the fur brush 35 so that the developer does not affect the developer leakage prevention sheet 52. Note that the developer leakage prevention sheet 52 has a thickness of 60 to 2
It is a 00 μm urethane sheet.

In the conventional developing device configured as described above, the developer leak prevention member 51 stops most of the developer blown out from the fur brush 35, and the urethane sheet that is the developer leak prevention sheet 52 is placed in close contact with the developing roller. ing. Since the amount of developer on the developing roller 34 scraped off by the developer leak prevention sheet 52 is very small, it does not accumulate in the spill storage space and spill outside.

However, in the above structure, even if the gap between the developing roller 34 and the casing 29 is sealed at both ends of the developing roller 34 in the longitudinal direction, the developer 28 cannot be easily solved in the longitudinal direction of the developing roller 34. The developer is conveyed to both ends of the sandblasted surface and the smooth surface, and stops at the boundary between the sandblasting surface and the smooth surface.
2 scrapes off, resulting in a large amount of spillage. Therefore, there is a problem that the spillage cannot be stored in the space of the spill storage section, and the spillage falls outside.

In view of the above, the present invention provides a developing device that facilitates sealing at both ends of the developing roller in the longitudinal direction and eliminates the problem of thick coating of developer on both ends of the developing roller in the longitudinal direction. The purpose is to provide

Means for Solving the Problems The developing device of the present invention includes a developer carrying member which is sandblasted except for both ends thereof, a developer supplying member having a width smaller than the sandblasting width of the developer carrying member, and the developer supplying member having a width smaller than the sandblasting width of the developer carrying member. A layer thickness regulating member provided in pressing contact with the developer carrier and regulating the amount of developer adhering to the developer carrier; and an opening through which the developer passes when conveying the developer to the developer supply member. The invention is characterized in that it includes a developer storage means.

Effect of the present invention With the above-described configuration, the developer supplied from the developer storage means to the developer supply member is developed at the opening,
Since the developer supply member is smaller than the sandblasting width of the developer carrier, it extremely weakens the conveyance force of the developer transported to both ends of the developer carrier in the longitudinal direction. The amount of developer penetrating through to both ends of the developer carrier is small, and it is possible to prevent the developer from being coated in a concentrated manner only near the boundary between the sandblast surface and the smooth surface at both ends of the developer carrier in the longitudinal direction.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the accompanying drawings.

In Fig. 1, numeral 1 denotes a photoconductor drum which is a charge carrier, and is made of a metal base 2 made of aluminum or the like, coated with a photoconductor 3 made of zinc oxide selenium electrostatic material, etc., and rotates clockwise. It is rotating. A charger 4 is configured to charge the entire surface of the photoconductor 3 of the photoreceptor drum 1 to a predetermined polarity using a DC high voltage power source (not shown). Reference numeral 5 denotes an optical section that projects a patterned optical image onto the photosensitive drum 1 to form an electrostatic latent image. 6 is a developer, which is a -polar or non-magnetic one-component insulating toner. 7 is a developing roller (hereinafter referred to as developing roller) which is a developer carrier, and is made of stainless steel, for example.
A solid or hollow roller made of aluminum or the like is effectively used and sandblasted except for both ends. The developing roller 7 is installed at a constant distance from the photosensitive drum 1, and rotates counterclockwise. 8
is a developer supplying member having the ability to charge the developer 6 to a predetermined polarity; for example, a fur brush, a sponge roller, etc. are effectively used, and the member slides against the developing roller 7 and rotates clockwise around the developing roller 7. It is rotating at higher speeds.

Note that the width 52 of the developer supplying member 8 is smaller than the sandblasting width L3 of the developing roller 7, as shown in FIG.

Reference numeral 9 denotes a developer storage means, which includes a storage section 10 that stores the developer 6.
The developer conveying means 12 rotates clockwise around a support shaft 11, and has a partition plate 13 inside. This partition plate 13 serves as the storage section 1 of the developer storage means 9.
0 and the developing roller 7, and an opening 14 through which the developer 6 enters and exits is formed so as to be in contact with the developer supplying member 8 located between them.

As shown in FIG. 2, the width of the developer supply member 8 and the width of the opening 14 are set to be equal and larger than the image area width L+ of the developing roller.

Reference numeral 15 denotes an elastic blade which is a layer thickness regulating means for regulating the layer thickness of the developer 6 supplied to the developing roller rough, and is a rubber blade made of urethane rubber, silicone rubber, etc., or an elastic metal blade made of phosphor bronze, spring steel, etc. for springs. It is used effectively. The length in the longitudinal direction of the layer thickness regulating means 15 is configured to be longer than the width of the developing roller rough, and one end is connected to the developing roller 7.
The developing frame 16 is fixed to the developing frame 16 so as to be in contact with the circumferential surface of the developing frame 16.

Next, the operation of the configuration of this embodiment will be explained.

The photoconductor 3 of the photosensitive drum 1 is charged by a charger 4 to a predetermined polarity, for example, negative. Next, this negatively charged photosensitive drum 1 is irradiated with a reflected light image (pattern light image) of the original by the optical section 5, forming a positive electrostatic latent image, which reaches the development area. The developer 6 stored in the storage section 10 of the developer storage means 9 is transferred to the partition plate 13 by the developer conveyance means 12.
The developer supplying member 8, which is a charging means, is supplied through the opening 14 of the
The developer is supplied into the developer supply member 8 and rubbed by the developer supply member 8 to be frictionally charged to a predetermined polarity, for example, positive.

The charged developer 6 is conveyed to a position facing the developing roller 7 by the rotation of the developer supplying member 8, and is supplied to the developing roller by its electrostatic force.

At this time, the width L2 of the developer supplying member 8 is made smaller than the sandblasting width L3 of the developing roller 7, and by making the width L2 of the developer supplying member 8 equal to the opening 14, the width L2 of the developer supplying member 8 is made equal to the opening 14. This will extremely weaken the transporting force of the developer 6 being transported. Therefore, the amount of toner applied to both ends of the developing roller 7 is reduced, and the amount of toner passing over the developing roller 7 to both ends is significantly reduced, so that the sealing of both ends of the developing roller 7 can be simplified. In addition,
Making the width of the layer thickness regulating member 15 larger than the width of the developing roller rough also helps to simplify the sealing at both ends. Furthermore, since the width of the image area of the developing roller is made shorter than the width of the developer supplying member 8, the amount of toner supplied to the portion of the developing roller that corresponds to the image area is reduced.
There is no such thing as the image not tracking.

Furthermore, since the amount of toner applied to the sandblasted surface at both ends of the developing roller 7 is small, the developer is coated only near the boundary between the sandblast surface and the smooth surface, and does not come into contact with the photoreceptor. Therefore, there is no possibility that the developer is scraped off to the seal member between the developing roller 7 and the bottom plate of the casing to the extent that it cannot be stored in the space of the storage section and spilled to the outside.

Experimentally, it is desirable that the width of the sandblasting surface is at least 2 mm longer on each side than the width of the developer supply member 8 in the center division of the developing roller ruff. It is desirable to set the length to be at least 1 mm longer on one side.

Next, when the developer 6 on the developing roller 7 whose layer thickness is regulated faces the electrostatic latent image on the photosensitive drum 1 in the developing area,
The electrostatic latent image is blown away by the electrostatic force, and the electrostatic latent image is developed.

Effects of the Invention In the present invention, by making the width of the developer supplying member smaller than the sandblasting width of the developing roller, it is possible to reduce the amount of toner applied to both ends of the developing roller. This simplifies the sealing of both ends of the developing roller, and also prevents the ends from being thickly coated with toner, causing the image to bulge out or spilling, making it possible to obtain good images. .

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a developing device in an embodiment of the present invention;
FIG. 2 is a dimensional relationship diagram of essential parts of the same device, and FIG. 3 is a sectional view of a conventional developing device. 7...Developing roller, 8...Developer supply member, 14...
...Opening portion, 15...Layer thickness regulating member. Name of agent: Patent attorney Toshio Nakao and one other person 7--Mud Statue Roller Figure I5-Grade Figure 3

Claims (3)

[Claims] (1) a developer carrier that has been sandblasted except for both ends; a developer supply member that has a width smaller than the sandblasting width of the developer carrier; and a developer supply member that is provided in pressed contact with the developer carrier; A layer thickness regulating member for regulating the amount of developer deposited on the developer carrier, and a developer storage means provided with an opening through which the developer passes when conveying the developer to the developer supplying member. Developing device. (2) The width of the developer supply member and the width of the opening should be equal;
2. The developing device according to claim 1, wherein the developing device is configured to be larger than the width of the image area. (3) The developing device according to claim 1, wherein the width of the developer carrier is smaller than the width of the layer thickness regulating member.