JPS6270880A - Developing device for electrostatic latent image - Google Patents

Abstract

PURPOSE:To obtain a small and simple developing deice by storing a developer in a netlike shape developing carrier and omitting a hopper part. CONSTITUTION:The developer carrier 1 having a net of about 200 meshes and consisting of metal or resin is covered with an enclosure 5 excluding the neighborhood of a developing part 8, a dry type one-component developer 3 is stored in a developer carrier 1 and a layer thickness regulating member 4 consisting of an elastic body such as silicone rubber and is abutted upon the inside/outside of the developer carrier 1. The developer 3 is agitated and moved in accordance with the rotation of the developer carrier 1, flows out from the net, electrostatically charged by friction between the net and the enclosure 5, uniformly coated on the developer carrier 1 by the member 4 and uniformly charged by friction with the member 4. At a developing position 8, the developer 3 is scattered to an electrostatic latent image on an electrostatic latent image carrier 2 to develop an image.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a developing device for a device that develops an electrostatic latent image, such as a copying machine or a printer, which uses electrophotography.

2. Description of the Related Art Dry development methods for developing electrostatic latent images are known in particular.
These methods are roughly divided into methods using component-based developers and methods using single-component developers.

The method using a two-component developer uses a developer that is a mixture of toner and carrier, so it requires a toner concentration control device to keep the mixture ratio of toner and carrier constant, and periodic replacement due to carrier deterioration. It has the disadvantage of being Therefore, recently, in order to eliminate the above-mentioned drawbacks, a developing method using a one-component developer without using a carrier has been proposed.

The example described in JP-A-68'-98761 is an example of a fiber brush method, and its outline is shown in FIG. That is, the brush 2 provided on the developer carrier 29 from the hopper 20
The developer 21 supplied to the brush 28 is regulated by a coating brush 22 that is in contact with the brush 28, and is uniformly coated on the brush 28, and the developer 21 is charged by friction between the brush 28 and the brush 22.

Next, when an alternating voltage is applied between the electrostatic latent image carrier 25 and the developer carrier 29 by the bias power supply 23, an alternating electric field is formed between them. The developer is discharged and electrostatically adheres to the electrostatic latent image on the electrostatic latent image carrier 26 in the developing section 26, thereby performing development.

Problems to be Solved by the Invention However, due to the structure of these systems, there is a limit to the miniaturization and simplification of the developing device. In other words, a hopper part for supplying developer to the developer carrier is essential outside the developer carrier. However, a certain amount of volume is required.

Therefore, an object of the present invention is to provide a small and simple developing device that does not require an external hopper section.

A means for solving the problems and a technical means of the present invention to solve the above-mentioned problems is to store the developer inside the mesh-like developer carrier, thereby eliminating the need for a hopper section.

For production The effect of this technical means is as follows.

That is, the developer stored inside the mesh-shaped developer carrier leaks out from the mesh as the developer carrier rotates, and is coated on the surface of the developer carrier by the layer thickness regulating member to form a thin layer. .

When this is brought close to the electrostatic latent image carrier, the developer is blown away by the potential of the latent image and development can be performed.

As a result, it is possible to provide a small and simple developing device that does not require a hopper section.

Example Examples of the present invention will be described below.

In FIG. 1, a developer carrier 1 is made of metal or resin and has a mesh size of about 5Q to 200 meshes.

This developer carrier 1 is housed inside a housing 5,
It is covered with a housing 6 except for the vicinity of the developing section 8. The developer 3 is a normal dry one-component developer and is housed inside the developer carrier 1. A layer thickness regulating member 4 is made of an elastic material such as silicone rubber and is brought into contact with the inside and outside of the developer carrier 1. Note that the layer thickness regulating member may be a rigid body and may be positioned with a gap equal to the layer thickness of the developer from the surface of the developer carrier 1. Reference numeral 2 denotes an electrostatic latent image carrier, which is an ordinary photosensitive drum, electrostatic recording paper, or the like. Reference numeral 6 denotes a partition plate to prevent the developer 3 from being directly deposited near the developing section 8, and 7 a bias power source for applying a bias voltage between the electrostatic latent image carrier 2 and the developer carrier 1. In this embodiment, the developer carrier 1 must be made of a conductive material.

The operation of this embodiment will be explained below.

The developer carrier 1 is rotated around its axis by a rotating means (not shown) and driven at approximately the same speed as the electrostatic latent image carrier 2 in the direction of the arrow. The gap between the developer carrier 1 and the electrostatic latent image carrier 2 is maintained at 0.5 mm or less.

As the developer carrier 1 rotates in the direction of the arrow, the developer 3 is stirred and moves in the rotational direction and oozes out from the mesh, but at this time it is charged by friction with the mesh and the casing 5. Further, when the developer carrier 1 rotates, the developer 3 oozes out.
is uniformly coated on the developer carrier 1 by the layer thickness regulating member 4, and is further uniformly charged due to friction with the layer thickness regulating member 4. In this state, when moving to the development position 8, the developer 3 flies toward the electrostatic latent image due to the synergistic effect of the two electrostatic forces of the electrostatic latent image on the electrostatic latent image carrier 2 and the bias voltage, and development is performed. It will be done. The developer 3 on the developer carrier 1 that was not used for development returns to the housing 6 as it rotates, but at this time new developer 3 oozes out from inside the developer carrier 1 and is carried on the developer. Since the body 1 is always coated with new developer 3, better images can be obtained.

Furthermore, according to the present invention, not only can the developing device be made smaller and lighter, but also the developing device can be positioned over a wide range of the electrostatic latent image carrier 2, so that it is possible to make the developing device particularly small and lightweight, so that it is possible to position the developing device over a wide range of the electrostatic latent image carrier 2. This is advantageous during formation.

Next, a second embodiment of the present invention will be described.

FIG. 2 shows a second embodiment of the present invention, in which reference numeral 9 denotes an electrode for applying a bias voltage, which has a pointed tip to concentrate charge. It is arranged on the back side of the carrier 1.

It is easy to understand that the same effect as in the first embodiment can be obtained by providing the bias applying electrode 9 and applying a bias voltage. In this embodiment, the developer carrier 1 may be made of an insulating material.

Next, a third embodiment of the present invention will be described.

FIG. 3 shows a third embodiment of the invention. 1
o is a scraping member for scraping off unnecessary developer, and is made of a brush with fibers of rayon or the like flocked to an aluminum core. When the scraping member 10 is rotated and brought into contact with the developer carrier 1, unnecessary developer remaining on the developer carrier 1 is scraped off.
In addition to the leaching of the developer 3 from the mesh (described above) as the developer 3 rotates, new developer 3 is more reliably coated.
Even better images can be obtained.

Note that the scraping member 10 may be made of an elastic material such as a polyethylene terephthalate resin film and brought into contact with the developer carrier 1.

Next, a fourth embodiment of the present invention will be described.

FIG. 4 shows a fourth embodiment of the present invention, in which a recording paper 11 is held in a fixed shape by a support roller 16, and is approximately connected to the developer carrier 1 by a driving means (not shown'). It is driven at a constant speed in the direction of the arrow. 12 is a multi-needle electrode that forms an electric field between it and the back electrode 13, and also serves as a signal source 15.
A different signal voltage is applied to each recording needle, and the developer 3 on the developer carrier 1 is caused to fly in response to the signal.

14 is a bias power supply, which connects the multi-needle electrode 12 and the back electrode 1.
A bias voltage is applied between 3 and 3.

As already described in the first embodiment, as the developer carrier 1 rotates, the developer 3 oozes out from the mesh, becomes electrically charged, and is uniformly coated on the developer carrier 1. When the developer carrier 1 rotates to the development position 8, only the portion of the multi-needle electrode 12 corresponding to the recording needle to which a signal is applied from the signal source 15 flies onto the recording paper 11 by electrostatic force, forming an image. Here, application of a bias voltage by the bias power supply 14 helps the developer to fly due to electrostatic force.

With this embodiment, there is no need to use specially processed electrostatic recording paper as an electrostatic latent image carrier, or to transfer the image after developing it on a photosensitive drum coated with a photoconductive material. , and can be recorded directly on plain paper.

Next, a specific example of the electrostatic latent image developing device according to the present invention will be described.

Specific Example 1 In the first example of the present invention, positive development was carried out, and the developer carrier 1 was a 100-mesh stainless steel net, the developer 3 was a commercially available dry one-component developer, and an electrostatic latent image. A normal selenium photoreceptor is used as the carrier 2, the distance between the electrostatic latent image carrier 2 and the developer carrier 1 is Q, 16wn, and a bias voltage of -10° is applied to the developer carrier 1 to form a latent image. potential +900V, process speed 100 mm/
Sec (the electrostatic latent image carrier 2 and the developer carrier 1 were driven at a constant speed of 5), a good image was obtained.

Concrete Example 2 In a second example of the present invention, an electrostatic latent image was carried using the same materials and conditions as in Concrete Example 1 (however, no bias voltage was applied to the developer carrier 1). A good image was obtained when a voltage of -2.6 Kv was applied with the gap between the body 2 and the bias applying electrode 9 being 1-.

Specific Example 3 In the third embodiment of the present invention, using the same materials and conditions as in Specific Example 1, a brush in which rayon fibers were flocked at a density of 36,000 fibers/cA was used as the scraping member 10 at a circumferential speed of 100 wn/cA. When it was rotated with SeC and brought into contact with the developer carrier 1, it was observed that the developer 3 was reliably scraped off.

Specific Example 4 In the fourth example of the present invention, 1 is used as the developer carrier 1.
00 mesh stainless steel, developer 3 is a commercially available dry single-component developer, multi-needle electrode 12 is 0.2 in diameter.
The developer carrier 1 is made by arranging tungsten i having a diameter of 0.25 mm on a plane at intervals of 0.25 mm so that a signal from a signal source 15 can be applied to each one, and using ordinary plain paper for copying machines as the recording paper 11. and the distance between the recording paper 11 and the multi-needle electrode 12
The signal source 1 is
5, the recording speed was 50 using a pulse with a peak value of 5ooV.
Good images were obtained when recorded at mm/SeC.

Effects of the Invention The present invention stores a developer inside a mesh-like developer carrier, and controls the developer that oozes out from the mesh as the developer carrier rotates by controlling the surface of the developer carrier using a layer thickness regulating member. The system coats the surface to form a thin layer, and uses the latent image potential to cause the developer to fly and develop.This not only allows for a compact and simple developing device that does not require a hopper, but also allows the developer to ooze out. New developer is always used and good images can be obtained, and the attachment to the electrostatic latent image carrier has fewer positional restrictions, making it advantageous for forming color images that require multiple developing devices. Its practical effects are great.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an electrostatic latent image developing device according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view of an electrostatic latent image developing device according to a second embodiment of the present invention, and FIG. FIG. 4 is a sectional view of the electrostatic latent image developing device in the fourth embodiment, and FIG. 5 is a sectional view of the conventional device. DESCRIPTION OF SYMBOLS 1...Developer carrier, 2...Electrostatic latent image carrier, 3...Developer, 4...Layer thickness regulating member, 7... ...Bias power supply, 8...
Developing section, 9...Electrode for bias application, 1o...
... Scraping member, 11 ... Recording paper, 1
2...Multi-needle electrode, 13...Back electrode,
14...Bias power supply, 15...Signal source. Figure 2 2θ-゛One horn? 21.--Node elephant array 22-11 Yaderan 23-1-muia entry jK 24.-Suituta 8- Quiet begging; -11 Defushizz '-:t*+ttu+ 鈷 -゛【Year-

Claims (4)

[Claims] (1) It has a mesh-like developer carrier close to the electrostatic latent image carrier and developer layer thickness regulating members located inside and outside the mesh, and the developer is stored inside the developer carrier. Characteristic electrostatic latent image developing device. (2) The electrostatic latent image developing device according to claim 1, wherein a bias applying electrode is provided on the back surface of the developing section of the developer carrier facing the electrostatic latent image carrier. (3) The electrostatic latent image developing device according to claim 1, further comprising a scraping member for scraping off unnecessary developer remaining on the developer carrier. (4) A multi-needle electrode placed on the back side of the developer carrier facing the recording paper on which an image is recorded, a back electrode placed on the back side of the recording paper facing the multi-needle electrode, and means for applying a bias voltage between both electrodes. An electrostatic latent image developing device according to claim 1.