JPH05210293A - One-component developing device - Google Patents

Abstract

PURPOSE:To prevent fogging in initial printing by providing a mechanism releasing the contact of a latent image carrier and a developer carrier. CONSTITUTION:In a developing system for abolishing a waste toner recovery box which is a problem on the restriction of a device, a developing roller 1 whose surface is coated with toner 5 not including magnetic powder and which has the developer carrier, a photosensitive body 10 whose surface has the formation of an electrostatic latent image, a transfer belt 13 transferring/holding an image on the photosensitive body 10, developed by the developing roller 1, and the mechanism for releasing the contact of the photosensitive body 10 and a carrier for the toner 5, are provided, and the contact of the developing roller 1 and the photosensitive body 10 is controlled, at the time of starting a process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image recording apparatus such as a printer, a facsimile or a copying machine using an electrophotographic process, and more particularly to a one-component developing device.

[0002]

2. Description of the Related Art Conventionally, electrophotographic recording systems include a one-component developing system and a two-component developing system. There are two types of one-component developing systems related to the present invention: magnetic and non-magnetic. this house,
Although a magnetic one-component obtained by mixing magnetic particles with toner has been put into practical use for a long time, it is desired to develop a non-magnetic one-component developing method which has a simpler mechanism and can realize clear color in a small model.

Also, two-component magnetic brush development and Japanese Patent Publication No.
In magnetic one-component development as seen in -43037, the developer adheres to the developing roller due to the magnetic force,
The image carrier is developed only under an electric field above a certain developing electric field. For these developing methods, as a developing device using a non-magnetic developer that does not use a magnetic material, USP 3,75
Impression development is known in which a thin layer of toner is formed on a conductive elastic roller as disclosed in U.S. Pat. JP-A-52-143831
Describes a method of selectively applying a developing bias voltage to an elastic developing roller when developing a non-magnetic toner.

[0004]

In the conventional one-component developing device described above, the potential of the uncharged area on the photosensitive member, which was between the charger and the developing roller at the start of printing, becomes the GND level after being left for a long time. The developing bias voltage is applied as it is, or the developing bias circuit is cut off,
Even if the circuit is connected to the GND level, in the case of non-magnetic toner, the force is received only by the electrostatic force, so the toner adheres to the photoconductor due to the image force between the toner and the photoconductor or the Van der Waals force. Resulting in. For this reason, the amount of toner consumed increases, it is necessary to install a waste toner collecting container, and moreover, the capacity of the waste toner collecting container must be increased.

In the developing method in which the waste toner collecting container according to the prior art is abolished, at the start of the process, the surface potentials of the photosensitive member and the developing roller are not stable, and the developing roller and the photosensitive member start rotating in contact with each other. There is a drawback that a fog phenomenon that toner adheres to the background portion of the latent image occurs.

An object of the present invention is to provide a developing roller 1 having a developer carrier on the surface of which a toner 5 containing no magnetic powder is applied in a developing system in which a waste toner collecting box, which is a problem due to the restriction of the apparatus, is eliminated. A photoconductor 10 having an electrostatic latent image formed on its surface, a transfer belt 13 for transferring and holding an image on the photoconductor 10 developed by the developing roller 1, and a photoconductor 10.
And a mechanism for releasing the contact between the carrier and the carrier 5 and controlling the contact between the developing roller 1 and the photoconductor 10 at the time of the process start-up, thereby eliminating the above-mentioned drawbacks.
An object of the present invention is to provide a one-component developing device capable of preventing fogging in initial printing.

[0007]

SUMMARY OF THE INVENTION A one-component developing device of the present invention comprises a developing device having a developer carrier coated with a developer containing no magnetic powder, and a latent image forming electrostatic latent image on the surface. An electrophotographic image recording apparatus having an image carrier and an intermediate image carrier that transfers and holds an image on the latent image carrier developed by a developing device, and the latent image carrier and the developer carrier are in contact with each other. The developing device has a mechanism for releasing the contact between the latent image carrier and the developer carrier from the end of development to the start of next development.

The one-component developing device according to the second aspect of the present invention is the one-component developing device according to the first aspect, wherein the latent image carrier is driven while the developer carrier is not in contact with the latent image carrier. There is.

[0009]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a vertical sectional view of a one-component developing apparatus according to an embodiment of the present invention.

In FIG. 1, the photosensitive member 10 has an electrostatic latent image formed on its surface by the charging roller 11 and the light source 12, and the toner 5 of the developing unit 6 visualizes the electrostatic latent image. The toner adhered on the photoconductor 10 is transferred to the driving roller 1
Transfer belt 13 of an intermediate transfer medium driven by 8
Then, primary transfer is performed by the transfer roller 14. The toner on the transfer belt 13 is heated by the heater 15 and the pressure roller 16.
Is transferred to the recording medium 19 and fixed at the same time. Toner remaining without being transferred is cleaning pad 1
Removed by 7. The developing unit 6 stores the toner 5 therein, the stirring member 4 rotates clockwise in FIG. 1 to supply the toner 5 to the supply roller 3, and the supply roller 3 rotates counterclockwise to develop the toner. Toner 5 on roller 1
To supply. Toner is attached to the surface of the developing roller 2 by the supply roller 3, and the attached toner is limited to a certain thickness under the thin layer forming member 2. At this time, the toner is frictionally charged between the thin layer forming member 2 and the developing roller 1. The charged toner adheres to the developing roller 1 by the image force,
A uniform layer is conveyed to the contact area with the photoconductor 10. A voltage of several hundreds of volts is supplied to the developing roller 1 by a high voltage power source (not shown) to form a developing electric field with the photoconductor 10. Next, the operation of the one-component developing device of this embodiment will be described.

When the apparatus is stopped, the developing roller 1 is rotated by the spring 9.
And the photoconductor 10 are in contact with each other. When the apparatus is started, the solenoid 7 pulls the developing unit 6 in the opposite direction of the photoconductor 10 by the start of the driver circuit 8 to bring the developing roller 1 and the photoconductor 10 out of contact with each other. In that state, the developing roller 1 rotates until the surface potentials of the developing roller 1 and the photoconductor 10 become stable. At the time of development, the driver circuit 8 is stopped, and the developing roller 1 and the photoconductor 10 are pressed against each other by the spring 9 to perform development.

When the apparatus is stopped, the developing roller 1 and the photoconductor 10
The development roller 1 and the photoconductor 10 are brought into pressure contact with each other after a certain period of time has elapsed since the development was started without contacting with the development. After the development, the contact between the developing unit 6 and the photoconductor 10 is released by the solenoid 7 and the original non-contact state is restored.

[0014]

As described above, the one-component developing device of the present invention, in the developing system in which the waste toner collecting box, which is a problem due to the limitation of the device, is abolished, when the process starts up,
By controlling the contact between the developing roller and the photosensitive member, it is possible to prevent fogging during initial printing.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a one-component developing device according to an embodiment of the present invention.

[Explanation of symbols]

 1 Developing Roller 2 Thin Layer Forming Member 3 Supply Roller 4 Stirring Member 5 Toner 6 Developing Unit 7 Solenoid 8 Driver Circuit 9 Spring 10 Photoreceptor 11 Charging Roller 12 Light Source 13 Transfer Belt 14 Transfer Roller 15 Heater 16 Pressure Roller 17 Cleaning Pad 18 Drive Roller 19 recording medium

Claims (2)

[Claims] 1. A developing device having a developer carrier coated with a developer containing no magnetic powder, a latent image carrier having an electrostatic latent image formed on the surface thereof, and the developing device developed by the developing device. A latent image carrier in a developing device of an electrophotographic image recording apparatus, comprising: an intermediate image carrier for transferring and holding an image on the latent image carrier, wherein the latent image carrier and the developer carrier are in contact with each other. A one-component developing device having a mechanism for releasing contact between the body and the developer carrier from the end of development to the start of next development. 2. The one-component developing device according to claim 1, wherein the latent image carrier is driven while the developer carrier is not in contact with the latent image carrier. ..