JPS6333144B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing method, and more specifically, in a developing method using a dry developer, residual toner is removed from a toner applying roller and new toner is supplied. The present invention relates to a developing method.

Conventionally, toner is usually applied to a toner application roller, the toner is charged by frictional charging or corona discharge during or after the application, and then the toner application roller is brought close to or in contact with the electrostatic image on the photoreceptor. , toner is applied to the electrostatic image to visualize it. The toner on the toner application roller is partially removed by the electrostatic image, and the remaining toner remains attached to the toner application roller and is rotated again and used repeatedly.

Therefore, a conventional drawback is that the toner that is used repeatedly deteriorates, which causes deterioration in image quality and reduction in image density.

An object of the present invention is to provide a developing method and apparatus that eliminates the above-mentioned conventional drawbacks, and is characterized in that a toner is applied onto a toner application roller at a location other than the latent image area on a moving latent image support. The present invention is a developing method that consumes remaining toner, removes it from a toner applying roller, constantly supplies new toner, prevents image deterioration, and stabilizes image density.

Embodiments and examples of the developing method according to the present invention will be described in detail below with reference to the drawings.

Although FIG. 1 shows a schematic configuration of an example of a copying device or a recording device to which the developing method according to the present invention can be applied, the present invention is not limited thereto.
In the figure, 1 is a photoreceptor that includes a photoconductive layer, and can be used with or without an insulating layer on the surface; the one shown is drum-shaped, but is not necessarily limited to this. Not done. Reference numeral 2 represents a known photosensitive charging device, and 3 represents a light image irradiation device that projects an original image, a light image, or a light beam modulated by an image signal. An electrostatic image is formed on the photoreceptor 1 by these. This electrostatic image forming process includes the so-called Carlson process, or Japanese Patent Publication No. 42-23910,
Publication No. 43-24748, Publication No. 42-19748, Publication No. 44-
The process described in Publication No. 13437 and other processes can be applied.

4 is a developing device based on the present invention, which forms a toner particle visible image in accordance with the electrostatic image on the photoreceptor 1. Reference numeral 5 denotes a transfer device that transfers the toner image onto a transfer material 6. Incidentally, in order to improve the transferability, the visible image may be charged in advance by corona discharge or the like before transfer. It is also possible to adopt a so-called electrostatic image transfer method in which the electrostatic image on the photoreceptor 1 is temporarily transferred to another image carrier and then converted into a visible image by the developing device 4. Reference numeral 7 denotes a cleaning device for cleaning and removing residual toner on the photoreceptor 1 after transfer, and for reusing it.

FIG. 2 shows one embodiment of the electrophotographic developing device according to the present invention. Reference numeral 11 denotes a conductive support of the photoreceptor 1, which is normally grounded. Reference numeral 12 denotes a latent image support made of a photoconductive layer supported by the conductive support 11 or a photoconductive layer having an insulating layer thereon. The formation of such an electrostatic image has been described with reference to FIG. 13 is a toner applying roller;
It has a sleeve shape, is connected to the illustrated power source so as to be able to apply a bias voltage, has the same polarity as the toner used, and is rotatable at a circumferential speed substantially constant with the latent image support 12. It is supported by support means. Reference numeral 16 denotes a toner container, and a toner application blade 15 is provided at the lower part of the side wall. Reference numeral 17 indicates replenishment toner in the toner container 16. A magnet roll 18 is fixedly or rotatably provided in the toner applying roller 13, and has a plurality of magnetic poles as shown. When fixed, the developing portion of the sleeve-shaped toner applying roller 13, that is, the photoreceptor 1
It has a magnetic pole facing the latent image support 12 above.

In FIG. 2, toner 17 is uniformly coated with a blade 15 on a toner application roller 13 facing the latent image support 12 and rotating at the same speed as the latent image support 12, and the toner layer 14 and the electrostatic image are brought into close proximity or in contact with each other. Develop. At this time, the remaining toner that is not used for development returns to the toner container 16 as the roller 13 rotates (in the direction of the arrow in the figure). The remaining toner that remains on the roller 13 because there is no electrostatic image can be collected and reused, but if collection is insufficient, the toner remains on the toner application roller. The toner particles are rotated many times, which damages the surface of the toner particles and causes the toner particles to deteriorate, resulting in failure to obtain good development.

The present invention was made in order to solve the above-mentioned problems during powder development of latent images.
Remove toner that is not used for development in a timely manner so that it does not remain on the toner application roller for a long time.
The toner application roller is constantly supplied with new toner. Toner that has not been used for development is removed from the roller by applying an electric field, such as by applying a bias voltage between the toner application roller and the latent image support at a location other than the image latent image area on the moving latent image support. This is carried out by generating residual toner on the toner applying roller and consuming the remaining toner onto the latent image support.

Therefore, new toner is always supplied onto the toner application roller, making it possible to stabilize the image. Toner consumption on the latent image support outside the image latent image area may occur before or after forming the image latent image to be copied, for example, when the document table or optical system backs up, or before or after repeating a certain copy cycle. good.

Further, the toner consumption on the latent image support member may be performed all at once over the entire circumference of the toner applying roller 13, or the operation may be performed in parts, so that the entire circumference is constantly consumed on average. It may be kept in a constant state.

Further, as a method for creating the required electric field, a bias voltage may be applied to the toner application roller 13, or a potential may be applied to the surface of the drum-shaped latent image support 12 as a photoreceptor using corona charging. An electric field may also be generated by holding it.

One of the preferred embodiments of the present invention will be described below.

Example The thickness of the toner layer 14 on the toner applying roller 13 is about 150μ, and the diameter of the toner applying roller 13 is about 150 μm.
In the developing section, the toner applying roller 13 is moved at a speed of 20 cm/sec in the same direction as the latent image support 12 with a distance of about 200 μm between the toner applying roller 13 and the latent image support 12 of 20 cm. was rotated to transfer the toner only in the image area toward the latent image support 12 in a non-contact state and develop it. Put enough magnetic toner 17 into the toner container 16 and use it when backing up the optical system.
Toner application roller 13 and latent image support 12 for 0.05 seconds
Bias power supply 19 with a bias electric field of 500V between
A bias voltage is applied to the toner application roller in order to apply it from the toner. The section in which this bias voltage was applied was shifted each time and adjusted so that it covered the entire circumference of the toner applying roller after a certain period of time. Place the toner in toner container 1.
6, and changes in image density were examined with and without applying a bias voltage.
The measurement results obtained are shown in FIG. According to this, it can be seen that the image density is more stable in case a when a bias voltage is applied than in case b when no bias voltage is applied even if the number of copies increases.

The developing method according to the present invention can be applied not only to developing electrostatic latent images but also to developing magnetic latent images.

As explained above, the present invention consumes toner from the toner applying roller onto the latent image support at a location other than the image latent image area on the moving latent image support, thereby constantly producing new toner on the toner applying roller. This is an electrophotographic developing method characterized by supplying toner particles, which prevents deterioration of toner particles, performs development with fresh toner particles, stabilizes image density, and prevents deterioration of image quality. ing.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of an example of an electrophotographic apparatus to which the developing method according to the present invention can be applied, FIG. 2 is a sectional view of essential parts showing an embodiment of the developing method according to the present invention, and FIG. 3 is a toner application FIG. 3 is a characteristic diagram showing changes in image density with respect to the number of copies when a bias voltage is applied and not applied between a roller and a latent image support. 1... Photoreceptor, 2... Photosensitizing charging device, 3...
Light image irradiation device, 4...Developing device, 5...Transfer device, 6...Transfer material, 7...Cleaning device, 1
1... Conductive support, 12... Latent image support, 13
...Toner applying roller, 14...Toner layer, 15
...Application blade, 16...Toner container, 17...
...Toner, 18... Magnet roll, 19... Bias power supply.

Claims (1)

[Claims] 1. In a developing method in which a toner layer on a toner application roller is developed while facing a latent image support, the toner remaining on the toner application roller is consumed in areas other than the image latent image area on the moving latent image support. A developing method characterized in that a new toner is supplied onto a toner application roller.