JP2003186299A - Single-component developing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a single-component developing device which is inexpensive and has superior durability by preventing toner from leaking by a developer carrier coated with resin. <P>SOLUTION: The single-component developing device 5 has a developer container 20 which contains a developer, a developing roller 11 which is supported rotatably at an opening part of the developer container 20 and carries and conveys the developer, and a restriction roller 14 which is brought into contact with a supply roller 12 supplying the developer to the developing roller 11 and the developing roller 11 to restrict the developer carried and conveyed by the developing roller 11, the developing roller 11 having its metallic mandrel coated with resin. An axial resin coating area 21 of the developing roller 11 is inside the position of an end seal 21' arranged at an end part of the developing roller 11. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying machine, a printer, and a fax machine, in which a single component toner is used to visualize an electrostatic latent image on an image carrier. The present invention relates to a developing device.

[0002]

2. Description of the Related Art A one-component developing device has an advantage that it can be constructed at a lower cost than a two-component developing device because it does not require a carrier or a toner concentration sensor. However, since the non-magnetic one-component developing device cannot regulate the developer by utilizing the magnetic force unlike the two-component developing device, various inventions have been made on the sealing property of the developer.
For example, in Japanese Patent Laid-Open No. 2000-75631, an image carrier having a metal roller surface blasted is used.
In order to prevent the developer from leaking to the outside, the surface treatment range is set inside the end seal configured to rub against the end sliding surface of the developer carrier, so that the developer is An invention has been proposed in which developer leakage is prevented by entering the part seal sliding friction portion and causing the developer to melt.

[0003]

However, the developer bearing member whose surface is blasted according to the present invention conveys the developer by the unevenness of the roller surface due to the blasting process, and therefore the unevenness is small with time. The developer conveyance amount is small, and the durability is poor.

In order to realize high durability in an inexpensive one-component developing device, the present inventors coat the surface of a metal cored bar with a resin as a developer carrying member so that the electrostatic charge of the resin is retained instead of the unevenness of the surface. Similarly to the blasting roller, the resin coating range was regulated in order to prevent the toner from entering the end seals even in the case where the developer was carried by force and coated with the resin. However, as compared with the case of the blasting roller, the resin coating roller has a problem that a step is formed between the resin coating portion and the metal roller portion, and toner leakage occurs at the step.

Therefore, the present invention has been made in view of the above problems, and provides a one-component developing device which prevents toner leakage by a resin-coated developer carrying member and is inexpensive and excellent in durability. The task is to do.

[0006]

In order to solve the above-mentioned problems, the invention described in claim 1 is a developing container for containing a developer, and a developer rotatably supported by an opening of the developing container. A developer carrying member to be carried and conveyed, a supply roller for supplying the developer to the developer carrying member, and a developer regulating member for contacting the developing roller to regulate the developer carried and conveyed by the developer carrying member. In the developing device in which the developer carrying body is formed by coating a metal cored bar with a resin, a resin coating region in the axial direction of the developer carrying body is arranged at an end portion of the developer carrying body. The one-component developing device is located inside the end seal position. The invention described in claim 2 is the one-component developing device according to claim 1, wherein the resin coating film pressure is 12 μm or less. The invention according to claim 3 is the same as claim 1.
In the one-component developing device described above, the resin coating is a one-component developing device that makes the film pressure at the end portion thinner than at the central portion.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of a printer using a one-component developing device according to an embodiment of the present invention. This printer includes a photoconductor 1 as a latent image carrier that is wound around a plurality of support rollers. The photoconductor belt 1 is rotationally driven in the clockwise direction shown by an arrow A in the figure, and around the photoconductor belt 1, a charger 3, an optical writing unit 4, four sets of developing devices 5Bk, 5C, 5M, 5Y and an intermediate transfer member are provided. The intermediate transfer belt 6, the photoconductor cleaning device 7, and the like are arranged. An organic photosensitive layer is formed on the surface of the photosensitive belt 1.

Image forming operation (printing operation) by the printer
When executing, the high voltage is applied to the charger 3 so that the photosensitive belt 1 is uniformly charged. And
In an image signal processing unit (not shown), color image information, for example, a color 4 image signal sent from an external computer is converted into an optical writing signal to be converted into an optical writing unit 4.
Sent to. In the optical writing unit 4, a laser as a light source (not shown) is controlled on the basis of the optical writing signal, and via the polygon mirror 8, the f / θ lens 9 and the reflection mirror 10, Black (Bk), Cyan.
Optical writing corresponding to the image signals of (C), Magenta (M), and Yellow (Y) is performed, and an electrostatic latent image is formed on the photosensitive belt 1. The electrostatic latent image on the photosensitive belt 1 is a one-component developing device 5 having toner of each color as a developer, which is charged with an electric charge having a polarity opposite to that of the latent image.
Development is performed for each color by BK, 5C, 5M, and 5Y.
As a result, a toner image is formed on the photosensitive belt 1 for each color.

At the contact portion between the photoconductor belt 1 and the intermediate transfer belt 6, a toner image on the photoconductor belt 1 is transferred onto the intermediate transfer belt 6 by applying a charge having a polarity opposite to that of the toner to the intermediate transfer belt 6. Is transcribed to. By repeating this toner image formation and transfer operation four times, a four-color superposed color toner image is formed on the intermediate transfer belt 6.
The color toner image on the intermediate transfer belt 6 is transferred from the paper feed cassette 40 or the manual feed tray 41 to the conveyance roller pair 42.
Is transferred by a paper transfer roller 43 as a secondary transfer member onto the transfer paper as a recording material sent by
The transfer paper on which the color toner image is transferred is a fixing roller pair 4
The toner image is conveyed to a fixing unit composed of 4 and the toner image is fused and fixed.

FIG. 2 is a schematic diagram showing the structure of a one-component developing device according to the embodiment of the present invention. The one-component developing device 5 is a one-component developing type developing device using non-magnetic one-component toner (hereinafter referred to as “toner”). Each one-component developing device 5 includes a developing container 10 having an opening toward the photoconductor belt 1, a developing roller 11 as a developer carrying member, a supply roller 12 for supplying toner onto the developing roller 11, and a developing container. A toner containing portion 18a in
Supply roller 1 for supplying the toner contained in 18b and 18c
The transport paddles 17a, 17b, 17c sent to the second side, and a developer for contacting the developing roller 11 and regulating the layer thickness of the toner carried on the developing roller 11 to form a toner layer having a predetermined layer thickness. It has a regulation roller 14 as a layer regulation roller. The developing roller 11 is the developing container 1.
Part of the opening 0 is exposed so that it can rotate counterclockwise at a predetermined linear velocity during development, and the toner is carried on the roller surface and is a contact portion with the photosensitive belt 1. The latent image formed on the photosensitive belt 1 is conveyed to a position where the latent image is developed. The toner supply roller 12 is in contact with the developing roller 11 with a predetermined pressure, and the surface portion thereof is made of foamed polyurethane.

A toner regulating blade 13 is brought into contact with the toner supplying roller 12 so that the amount of toner supplied to the developing roller 11 is regulated. Each of the transport paddles 17 is rotatably installed in the counterclockwise direction of the arrow, and the toner is sent to the supply roller 12 side by this rotation. As a material of each of the transport paddles, for example, a soft and elastic material such as polypropylene can be used, and by utilizing the elasticity, the toner rotates reliably in a state of being brought into close contact with the inner wall of the developing container 20 to reliably transport the toner. The regulation roller 14 regulates the toner on the developing roller 11 to have a predetermined layer thickness, and frictionally charges the toner by slidingly contacting the toner. The toner charged on the developing roller 11 develops the electrostatic latent image on the photosensitive belt 1. In this embodiment, urethane rubber coated with resin is used as the material of the surface portion of the regulation roller 14. Further, a regulation roller cleaning blade 16 is in contact with the regulation roller 14, so that the surface of the regulation roller 14 that has passed the contact portion with the developing roller 11 is cleaned. Further, the developing roller 11 and the regulation roller 14 due to environmental changes such as humidity.
A spring 19 is provided as a biasing means for the regulating roller 1
4 is pressed against the developing roller 11.

Further, in order to prevent the toner from leaking out from the gap between the developing roller 11 and the developing container 20, an inlet seal member is extended on the inner surface of the developing container 20 so that the front end of the developing roller 11 contacts the surface of the developing roller 11. End seals 15 '
Is provided. The independently rotatable cams 50 are in contact with the side ends (left side in the drawing) of each one-component developing device 5, and are separated from the photoconductor belt 1 when not developing,
Prior to development, the developing roller 11 is configured to perform a contact / separation operation such that the developing roller 11 moves to a developing position where the photosensitive belt 1 comes into contact with the photosensitive belt 1 in a predetermined positional relationship. When developing the electrostatic latent image on the photosensitive belt 1, for example, B
When the electrostatic latent image of k is formed on the photoconductor belt 1, the cam located at the rear of the one-component developing device 5Bk is rotationally driven by 180 degrees by a drive control unit (not shown), and the one-component developing device 5Bk is rotated.
Bk is pushed out to the side of the photoconductor belt 1 and the developing roller 11
Bk moves to the developing position where it contacts the photosensitive belt 1. The same applies to the one-component developing devices 5C, 5M, and 5Y of other colors.

FIG. 3 is a schematic view showing a structure of a developing roller used in the one-component developing device according to the embodiment of the present invention. FIG. 4 is a schematic diagram showing a configuration of an end portion of the one-component developing device according to the embodiment of the present invention. Figure 5
FIG. 3 is a cross-sectional view showing a positional relationship among an end seal of a developing roller portion, a developing roller, a regulating roller, and a supply roller of a one-component developing device according to an embodiment of the present invention. FIG. 6 is a perspective view of a portion for showing the positional relationship among the end seal of the developing roller, the developing roller, the regulating roller, and the supply roller of the one-component developing device according to the embodiment of the present invention. Here, in order to prevent the toner leakage to the outside, the area of the resin coating area 21 in which the surface of the developing roller 11 is resin-coated is rubbed against the surface of the end portion of the developing roller 15 '. I did not overlap with. Specifically, in the figure, b of the developing roller 11 indicates the resin coating region 21 within a range in which a is in contact with the developing roller 11 and the supply roller 12.

When the developing operation is repeated a large number of times, the toner is conveyed to the sliding surface of the end seal 15 ', the toner having entered the end seal 15 is melted, and the performance of the end seal 15' is deteriorated. However, the inside of the image forming apparatus is contaminated with toner. Therefore, the resin coating area is set so as not to cover the end seal portion 15 so that the toner is not conveyed to the end seal portion 15. As a result, the toner does not enter the end seal portion 15. The resin-coated developing roller 11 uses the surface irregularities of the developing roller, which is conventionally used to convey toner, while the developing roller 11 uses the electrostatic holding force of the resin. Like the developing roller described above, the unevenness of the surface becomes small with the passage of time, and the toner conveyance amount does not decrease, and the durability is excellent. As the resin material, a non-staining material for the photoreceptor belt 1 is selected, and urea resin, melamine resin, alkyd resin, modified alkyd resin such as phenol-modified or silicone-modified, acrylic resin, silicone resin, fluororesin,
Examples thereof include phenol resin, polyamide resin, epoxy resin, polyester resin, maleic acid resin and the like. In particular,
Of these, urea resin, melamine resin, acrylic resin and the like are preferable from the viewpoint of film-forming property and adhesiveness.

The film thickness of the resin coat 21 'applied to the resin coating region 21 is set to 12 μm or less. Resin coating area 21 and non-resin coating area 22
The (metal part) has a step difference corresponding to the film thickness. This step causes a gap between the developing roller 11 and the regulating roller 14 that is in contact with the developing roller 11 for the purpose of regulating the toner layer thickness.
Therefore, the toner leaks from the gap. Therefore, with the developing roller 11 of the one-component developing device 5,
By setting the film thickness of the resin coat 21 ′ to 12 μm or less,
The step is reduced to prevent toner leakage. The step difference of 12 μm is such that the average particle diameter of the toner is around 8 μm and the toner cannot pass through two or more particles.

FIG. 7 is a schematic view showing the structure of the end portion of the developing roller of the one-component developing device according to the embodiment of the present invention. Further, the end portion film thickness c of the resin coat 21 ′ applied to the resin coating region 21 is made thinner than the central portion film thickness e. Instead of thinning the film thickness of the resin coat 21 ', the film thickness of the resin coat 21' is made to have a slope outside the image guarantee region, as in the inclined region d. This makes it possible to reduce the step due to the film thickness c of the end portion without reducing the film thickness e of the central portion. As a result, the resin coat 2
It is possible to eliminate electrostatic instability due to a decrease in the film thickness of 1 ′, and to prevent toner leakage without decreasing the central part film thickness e which is the film thickness in the image forming region. it can.

[0017]

As described above, in the one-component developing device according to the first aspect, it is possible to prevent the toner from entering the end seals with time in the highly durable resin coating roller. In the one-component developing device according to the second aspect, it is possible to prevent toner leakage from the step by reducing the step between the resin coating region and the metal part. In the one-component developing device according to the third aspect, the step difference at the end portion can be made small without reducing the film thickness at the center portion, so that toner leakage is prevented and an electrostatically stable image is always provided. Output is possible.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of a printer using a one-component developing device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a configuration of a one-component developing device according to an embodiment of the present invention.

FIG. 3 is a schematic diagram showing a configuration of a developing roller portion used in the one-component developing device according to the embodiment of the present invention.

FIG. 4 is a schematic diagram showing a configuration of an end portion of the one-component developing device according to the embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a positional relationship among an end seal of a developing roller portion, a developing roller, a regulating roller, and a supply roller of a one-component developing device according to an embodiment of the present invention.

FIG. 6 is a perspective view of a portion for showing the positional relationship between the end seal of the developing roller, the developing roller, the regulating roller, and the supply roller of the one-component developing device according to the embodiment of the present invention.

FIG. 7 is a schematic diagram showing a configuration of an end portion of a developing roller of the one-component developing device according to the embodiment of the present invention.

[Explanation of symbols]

1 photoconductor belt 3 charger 4 Optical writing unit 5 (One component) developing device 6 Intermediate transfer belt 7 Photoconductor cleaning device 8 polygon mirror 9 f / θ lens 10 reflective mirror 11 Developing roller 12 Toner supply roller 13 Toner regulation blade 14 Regulation roller 15 End seal 15 'end seal 16 Regulation roller cleaning blade 17 Transport paddle 18 Toner storage 19 spring 20 developer container 21 Resin coating area 21 'resin coat 22 Non-resin coating area 40 paper cassettes 41 bypass tray 42 Conveyor roller pair 43 Paper transfer roller 44 fixing roller pair 50 cams

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Claims (3)

[Claims] 1. A developer container containing a developer, a developer carrier rotatably supported in an opening of the developer container for carrying and carrying the developer, and a supply for supplying the developer to the developer carrier. The developer carrying member has a roller and a developer regulating member that comes into contact with the developing roller and regulates the developer carried and carried by the developer carrying body. The developer carrying body is formed by coating a metal cored bar with a resin. In the developing device, the one-component developing device is characterized in that the resin coating region in the axial direction of the developer carrier is inside an end seal position arranged at an end of the developer carrier. 2. The one-component developing device according to claim 1, wherein the resin coating film pressure is 12 μm or less. 3. The one-component developing device according to claim 1, wherein the resin coating makes the film pressure at the end portion thinner than at the central portion.