JPH0527567A - Developing device - Google Patents

Abstract

PURPOSE:To obtain a recorded image having high resolution over a long period without having fogging by efficiently electrifying toner. CONSTITUTION:A regulating member 29 is disposed in contact with a developing roller 22, and the layer thickness of the toner 25 on the surface of the developing roller 22 is regulated. The toner 25 is supplied from a metallic supplying roller 23 to the developing roller 22, so that a means generating an electric field between the developing roller 22 and the supplying roller 23, is provided. At this time, a metallic supply regulating member 27 is disposed on the supplying roller 23 in such a manner that the surface of the stem of the member 27 is press-contacted to the supplying roller 23, regulates the layer thickness of the toner 25 on the surface of the supplying roller 23, and simultaneously, friction-charges it. A coating roller 24 is disposed on the supplying roller 23, so as to come into contact with it, and the toner 25 is supplied to the supplying roller 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device in an electrophotographic apparatus capable of performing uniform density recording without fog.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic recording apparatus, a charged photosensitive drum is irradiated with a light source to form an electrostatic latent image on its surface, and toner is attached to the electrostatic latent image for development. After that, the toner image is transferred onto a recording medium (see Japanese Utility Model Laid-Open No. 64-19964).

In this case, in order to attach toner to the electrostatic latent image, a developing device is provided facing the photosensitive drum. FIG. 2 is a sectional view of a conventional developing device. In the figure, reference numeral 1 denotes a non-magnetic one-component contact type developing device which stores a developer (toner) 3 in a developer container 2. The developer accommodating tank 2 has a coating member 5 and a stirring member which are composed of a developer carrier 4 rotating at a predetermined speed and a porous elastic body roller contacting the developer carrier 4 and rotating in the same direction. 6 is provided. The toner 3 stirred by the stirring member 6 is
It is conveyed in the direction of the coating member 5, is triboelectrically charged between the developer carrying member 4 and the coating member 5, and adheres to the surface of the developer carrying member 4. Then, the toner 3 is rubbed by the regulating member 7 and regulated to form a developer layer having a predetermined thickness on the surface of the developer carrying member 4. The developer layer is supplied to the surface of the electrostatic latent image carrier 8 to form a visible image,
On the other hand, the toner 3 remaining on the surface of the developer carrying member 4 is collected in the developer container 2 by the collecting member 9.

In the developing device 1 having the above structure, the contact type developing method in which the electrostatic latent image carrier 8 and the developer carrier 4 contact each other is used. Therefore, when the charge amount of the toner 3 is increased, 3 sufficiently adheres to the electrostatic latent image carrier 8.

[0005]

However, in the developing device having the above structure, the electrostatic latent image carrier 8 and the developer carrier 4 need to be brought into uniform contact with each other. Material (rubber) must be used.
Further, in order to prevent the surface of the developer carrying member 4 from being scratched, a regulating member 7 for regulating the developer layer on the developer carrying member 4 is provided.
Should also use rubber. Therefore, even if the pressing force of the regulating member 7 is increased, there is a limit in increasing the charge amount of the toner 3, and the same toner 3 is used as compared with the two-component developing method in which the carrier 3 and the toner 3 are mixed and stirred. The amount of electric charge is about 1/3 to 1/5 even when the is charged.

On the other hand, when the metal blade is pressed against the metal roller and the toner 3 is charged by the method of rubbing the toner 3, it is about half of the two-component developing method.
It can be seen that it is charged to some extent. The present invention solves the above-mentioned problems of the conventional developing device and utilizes a non-magnetic one-component contact type developing system to efficiently charge the toner and produce a high-resolution recorded image without fog for a long period of time. An object is to provide a developing device that can be obtained.

[0007]

Therefore, in the developing device of the present invention, the developing device of the present invention is arranged in contact with the electrostatic latent image carrier and supplies a non-magnetic one-component developer to the electrostatic latent image carrier. Then
The electrostatic latent image on the electrostatic latent image carrier is visualized. Therefore, the developing device has a developer carrier arranged in contact with the electrostatic latent image carrier,
The developer is carried by the developer carrying body and moved to the electrostatic latent image carrying body. Further, a metal supply roller is arranged in contact with the developer carrying member. The supply roller supplies the developer to the developer carrier. Further, an application roller is provided in contact with the supply roller, and the developer is supplied to the supply roller.

A regulating member is disposed in contact with the developer carrying member to regulate the layer thickness of the developer on the surface of the developer carrying member. Further, a metal supply regulating member is provided by pressing the abdominal surface against the supply roller so as to regulate the layer thickness of the developer on the surface of the supply roller and to frictionally charge the developer. Further, means for generating an electric field is provided between the developer carrier and the supply roller.

[0009]

According to the present invention, the developing device is arranged in contact with the electrostatic latent image bearing member as described above, and the non-magnetic one-component developer is supplied to the electrostatic latent image bearing member. The electrostatic latent image on the electrostatic latent image carrier is visualized. The surface of the electrostatic latent image carrier is charged by a charging process, and an electrostatic latent image corresponding to an image is formed on the surface by an exposure process. The developing device forms a visible image by supplying a charged developer to the electrostatic latent image.

Therefore, the developing device has a developer carrying member arranged in contact with the electrostatic latent image carrying member. The developer carrying member carries the developer, and It moves to the latent image carrier. At this time, a regulating member is disposed in contact with the developer carrying body to regulate the layer thickness of the developer on the surface of the developer carrying body. The developer is supplied to the developer carrier from a metal supply roller. Therefore, means for generating an electric field is provided between the developer carrier and the supply roller. At this time, a metal supply restriction member is disposed on the supply roller with the surface of the abdomen pressed against the supply roller to restrict the layer thickness of the developer on the surface of the supply roller and to frictionally charge the developer.

An application roller is provided in contact with the supply roller, and the developer is supplied to the supply roller.

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a sectional view of the developing device of the present invention. In the figure, 20 is a developing device, and 21 is a photosensitive drum, which forms an electrostatic latent image on the surface through a charging process and an exposure process (not shown), and reaches the developing process.
Reference numeral 22 denotes a developer carrying member made of elastic rubber, that is, a developing roller, which is arranged in contact with the photosensitive drum 21, and rotates in the direction of the arrow in the figure. A metal supply roller 23 is disposed in contact with the developing roller 22 in a pressed state and rotates in the direction of the arrow in the figure.

Reference numeral 24 is a coating roller, which is a supply roller 23.
The toner 25 of the non-magnetic one component is conveyed to the surface of the supply roller 23 by friction and mechanical effect. Reference numeral 26 is a coating power source, and the coating roller 24
An electric field is generated between the supply roller 23 and the supply roller 23 to adhere the toner 25 from the application roller 24 to the supply roller 23. Reference numeral 27 is a supply regulation blade made of an elastic metal, and the surface of the abdomen is pressed against the supply roller 23 to regulate the layer thickness of the toner 25 and to be charged.

Reference numeral 28 denotes a supply power source, which generates an electric field between the developing roller 22 and the supply roller 23 to adhere the toner 25 from the supply roller 23 to the developing roller 22. Also, 2
9 is a regulation blade, which is pressed against the developing roller 22,
The uneven toner layer on the developing roller 22 is regulated and made uniform over the entire axial direction. 30 is a developing power source,
An electric field is generated between the developing roller 22 and the photosensitive drum 21,
The toner 25 is attached to the photosensitive drum 21 from the developing roller 22. Reference numeral 31 denotes a recovery blade, which is a toner 25 remaining on the surface of the developing roller 22 without contributing to the development of the electrostatic latent image.
Is collected in the developer storage tank 32, and the developer storage tank 32
The toner 25 inside is pressed against the developing roller 22 so as not to leak out of the developer accommodating tank 32.

In the developing device 20 having the above structure, first,
The toner 25 in the developer storage tank 32 is conveyed to the vicinity of the application roller 24 by the stirring roller 33. The coating roller 24 conveys the adhered toner 25 to a position facing the supply roller 23 by a mechanical effect. At this time, a potential difference is provided between the coating roller 24 and the supply roller 23, and an electric field is generated and the coating roller 24 and the supply roller 23 are generated.
By generating friction between them, the toner 25 is charged and conveyed to the supply roller 23 by an electrostatic force. The toner 25 carried on the supply roller 23 is regulated and charged by the supply regulation blade 27. At this time, the amount of charge of the toner 25 on the supply roller 23 is larger than that when the toner 25 is charged between the rubber supply roller and the supply regulation blade.

Next, the charged toner 25 is conveyed to the developing roller 22 by an electrostatic force due to the electric field between the supply roller 23 and the developing roller 22, and is regulated to a desired thickness by the regulating blade 29 to be uniformized. .. After that, the undeveloped toner 25 passes through the recovery blade 31 and the developer container 3
Return to 2 Here, the amount of toner 25 on the photosensitive drum 21 required to obtain the recording density of 1.3 is such that the developing efficiency is 8
When it is 0% and the transfer efficiency is 80%, it becomes 0.9 mg / cm ² or more.

The amount of toner 25 conveyed to the photosensitive drum 21 is w ₀ , the peripheral speed of the photosensitive drum 21 is v ₀ , and the amount of toner 25 conveyed to the developing roller 22 before passing the regulation blade 29 is w _d. , The amount of toner 25 conveyed to the developing roller 22 after passing the regulation blade 29 is w _d ′, the peripheral speed of the developing roller 22 is v _d , the amount of toner 25 regulated by the supply roller 23 is w _p , when the peripheral speed of the feed roller 23 and the _{v p, w 0 = (v} d / v 0) ' a _{w d = (v p / v} d) · w p, this time, w _d' · w _d ≦ The amount w _{d of the} toner 25 conveyed to the developing roller 22 before passing through the regulation blade 29 is set so that w _d is satisfied.

In the above embodiment, the peripheral speed ratio (v _d / v ₀ ) between the photosensitive drum 21 and the developing roller 22 is 1.5, and the peripheral speed ratio (v _p / v _d ) between the supply roller 23 and the developing roller 22 is 1.
(Constant speed), the amount (w _p ) of the toner 25 on the supply roller 23 is 0.6 mg / cm ² . The developing roller 22 has a stainless steel shaft covered with conductive rubber and urethane coated around the shaft.
Is an aluminum pipe that is mirror-finished (diameter 20 mm, surface roughness 3 μm R _Z ), subjected to high temperature alkali etching, and then hard anodized. It is coated.

Further, the toner 25 is made of various thermoreversible resins such as styrene resin in which a pigment of carbon black or a polarity control agent is dispersed, and has an average particle size of about 10 μm. Is sus304-c
If the sp has a thickness of 200 μm, the regulation blade 29
Is a urethane rubber having a thickness of 2 mm (JIS A rubber hardness 70 °), and the recovery blade 31 is a polyester film.

In the developing device 20 having the above structure, the linear pressure of the supply regulating blade 27 is 200 g / cm, the linear pressure of the regulating blade 29 is 100 g / cm, and the voltage of the supply power source 28 is 4 g.
00V, coating power supply 26 voltage 200V, developing power supply 30
Is set to 400V. That is, when the photosensitive drum 21 is set to zero potential, the potential of the developing roller 22 is -400V,
The surface potential of the supply roller 23 is -800 V, and the coating roller 2
The surface potential of No. 4 is -1000V, and the surface potential of the photosensitive drum 21 is -800V.

In this state, a test was conducted to print 10,000 images on A4 size recording paper at a process speed (moving speed of the outer periphery of the photosensitive drum 21) of 60 mm / s. As a result, during the printing of 10,000 sheets, even if the image is visually viewed, the scattering and aggregation of the toner 25 are substantially negligible, and a very good printing result can be obtained. It was

That is, since the toner 25 is frictionally charged by the metal supply roller 23 and the metal supply regulation blade 27, the charging amount is made larger than in the case where the conventional rubber supply roller and the supply regulation blade rub. Since it can be supplied to the developing roller 22, it is possible to provide a recorded image with high resolution without fog for a long period of time. The present invention is not limited to the above-mentioned embodiments, but can be variously modified based on the spirit of the present invention.
They are not excluded from the scope of the present invention.

[0023]

As described in detail above, according to the present invention, the developer carrying member is provided in contact with the electrostatic latent image carrying member, and regulated by the developer carrying member. The developer having the specified layer thickness is carried and moved to the electrostatic latent image carrier.
The developer is supplied to the developer carrier from a metal supply roller. At this time, a metal supply restriction member is arranged on the supply roller with the surface of the abdomen in pressure contact with the supply roller to restrict the layer thickness of the developer on the surface of the supply roller and frictionally charge the developer.

Therefore, the supply roller and the supply restricting member come into contact with each other between the metals, and the amount of charge of the developer due to the friction generated between them increases, so that a high-resolution recorded image without fog can be obtained for a long period of time.

[Brief description of drawings]

FIG. 1 is a sectional view of a developing device of the present invention.

FIG. 2 is a sectional view of a conventional developing device.

[Explanation of symbols]

 20 Development Device 21 Photosensitive Drum 22 Development Roller 23 Supply Roller 24 Coating Roller 25 Toner 27 Supply Regulation Blade 29 Regulation Blade 31 Recovery Blade 32 Developer Storage Tank

Claims (1)

Claim: What is claimed is: 1. A developing device for supplying a non-magnetic one-component developer to an electrostatic latent image carrier to visualize the electrostatic latent image on the electrostatic latent image carrier. In (a) a developer carrier which is arranged in contact with the electrostatic latent image carrier and which carries and moves the developer, and (b) which is arranged in contact with the developer carrier. A metal supply roller for supplying the developer to the developer carrier, (c) an application roller arranged in contact with the supply roller for supplying the developer to the supply roller, and (d) the developer A regulating member which is disposed in contact with the carrier and regulates the layer thickness of the developer on the surface of the developer carrier; and (e) is disposed with the abdominal surface in pressure contact with the supply roller. A metal supply regulating member that regulates the layer thickness of the developer on the surface of the sheet and that is frictionally charged, and (f) the developer carrying member. Developing apparatus is characterized in that it comprises means for generating an electric field between the serial feed roller.