JPH1184857A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of preventing the occurrence of density unevenness caused by a deficiency in the supply of toner onto a developing roller, occurring after a large quantity of toner on the developing roller is consumed for a solid image, etc. SOLUTION: The image forming device is provided with the developing roller 10 carrying the toner with which an electrostatic latent image formed on a photoreceptor is developed, a toner hopper for storing the toner, a toner supplying roller 6 for supplying the toner to the developing roller 10 and a layer thickness regulating blade 13 for regulating the thickness of a toner layer on the roller 10. In such a case, the property of electrifying the toner is enhanced between the toner supplying roller 6 and the developing roller 10 by the method of incorporating an electrostatic charge control agent 29 in the toner supplying roller 6, so that the property of supplying the toner to the developing roller 10 is enhanced and the density unevenness is prevented.

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 for visualizing an electrostatic latent image formed on a photoreceptor with toner particles in an electrophotographic apparatus or an electrostatic recording apparatus.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus such as an electrophotographic apparatus mainly uses a device using dry toner, and has been remarkably developed and put into practical use as many copying machines, laser printers, facsimile machines, and the like. . This electrophotographic device is a device to which electrophotographic process technology is applied. After the electrostatic latent image formed on the photoreceptor is visualized by toner particles, it is transferred to recording paper, and printing is completed through a fixing process. I do.

Hereinafter, a conventional image forming method and image forming apparatus will be described. FIG. 1 is a cross-sectional view of an image forming apparatus according to Embodiment 1 of the present invention, and FIG. 4 is a cross-sectional view around a developing roller in a conventional image forming apparatus.

A metal drum such as aluminum is used as a base material,
A photoreceptor layer such as selenium (Se) or an organic photoconductor (hereinafter, referred to as OPC) is provided on the outer peripheral surface of the photoreceptor 1 which is an electrostatic latent image carrier coated in a thin film. The charged charger 2 includes a charged wire 2a such as a tungsten wire, a metal shield plate 2b, and a grid plate 2c. The charging line 2a causes corona discharge to uniformly charge the photoconductor 1 via the grid plate 2c. The exposure light beam 4 emitted from the exposure optical system 3 is obtained by subjecting an image signal to light intensity modulation or pulse width modulation by a laser driving circuit (not shown), and forms an electrostatic latent image on the photoconductor 1.

Next, the developing device 5 will be described. A toner supply roller 6 serving as a toner supply member includes a toner hopper 7
The toner stirring member 8 is rotatably supported at both ends by a toner stirring member 8 which is bent in a rectangular shape, and supplies the toner 9 to the surface of a developing roller 10 which is a toner carrier. A conductive layer made of an elastic body such as a foamed material such as urethane or silicon is formed in a layer on the outer peripheral surface of the metal as a base material. (FIG. 4).

The layer thickness regulating blade 13 contacts the metal spring plate member 13 a and the developing roller 10.
b, and the layer thickness regulating member 13b is a metal spring plate member 13
An elastic member such as silicon or urethane is integrally formed at one end of a. The developing roller 10 and the toner supply roller 6 are made of a metal such as stainless steel as a base material, and elastic members such as urethane and silicon are formed in a layer on the outer peripheral surface thereof.
Both ends of the toner hopper 7 are rotatably supported. The toner stirring member 8 draws a circular trajectory with the rotation of the toner supply roller 6, and stirs the toner 9 to prevent aggregation of the toner 9 stored in the toner hopper 7, and transfers the toner 9 toward the toner supply roller 6. Transport. The toner 9 supplied by the toner supply roller 6 is frictionally charged by the toner supply roller 6 and the developing roller 10 and adheres to the developing roller 10 electrostatically. The toner 9 adhered to the developing roller 10 is regulated in toner layer thickness by the layer thickness regulating blade 13 and is further frictionally charged to form a thin layer on the outer peripheral surface of the developing roller 10. Thereafter, the developing roller 10 comes into contact with or close to the photoconductor 1, and
The toner 9 is transferred and adhered to a portion of the photoconductor 1 where the electrostatic latent image is formed by a bias voltage applied from the developing bias power supply 14 (FIG. 4) to visualize the electrostatic latent image. The layer thickness regulating blade 13 is attached to the blade holder 15 by screwing.

The recording paper 17 stored in the recording paper cassette 16 is sent out from the recording paper cassette 16 to a transport roller 19 one by one by a half-moon-shaped feeding roller 18. The fed recording paper 17 is transported by the transport roller 19 in the direction indicated by the arrow A. Registration roller 20
Is provided for temporarily stopping the recording paper 17 in order to match the toner image formed on the photoconductor 1 with the recording paper 17, and is in contact with the driven roller 21.
The transfer device 22 is a transfer wire 22 made of a tungsten wire or the like.
a and a shield plate 22b made of a metal plate. By applying a high voltage to the transfer line 22a, the transfer line 22a causes a corona discharge, and transfers the toner image on the photoconductor 1 onto the recording paper 17. The toner image transferred onto the recording paper 17 is pressed by a fixing device 25 composed of a heat roller 23 having a heat source therein and a pressure roller 24 in accordance with the rotation of the heat roller 23 and the pressure roller 24. The recording paper 17 is fixed by heat, and printing is completed.

The cleaner section comprises a cleaning blade 26 for scraping off the residual toner on the photoconductor 1 and a toner collecting container 27 for storing the scraped residual toner. There is provided a static eliminator 28 for effective cleaning.

[0009]

However, in the above-described conventional method and configuration, when a large amount of toner such as a solid image on the developing roller is developed and consumed, the developing method for the second and subsequent rotations of the developing roller is performed. In this case, there is a problem that the density is reduced as compared with the first rotation of the developing roller and density unevenness occurs. This is because, after a large amount of toner on the developing roller is consumed, the toner is frictionally charged between the toner supply roller and the developing roller, and the toner is electrostatically attached to the developing roller and supplied. This is caused when the amount of toner supplied to the developing roller cannot keep up with the amount of the toner being insufficient. As the peripheral speed of the developing roller increases with high-speed printing, the friction time between the toner supply roller and the developing roller becomes shorter, and effective charging such as improving the rise of toner charging is required. Further, if the toner charge amount is insufficient, fogging occurs in which the toner adheres to the non-image area.

An object of the present invention is to solve the above-mentioned conventional problems and to provide an image forming apparatus capable of stably obtaining a high-quality image.

[0011]

According to the present invention, there is provided a developer carrying member for carrying a developer for developing an electrostatic latent image formed on an image carrier; A developer storage tank for storing a developer, a supply member for supplying the developer to the developer carrying member, and a layer for thinning the developer on the developer carrying member and regulating the layer thickness of the developer An image forming apparatus including a thickness regulating member, wherein the supply member includes a charge control agent. With this configuration, the chargeability of the developer between the developer supply member and the developer carrying member is increased, and the supply of the developer to the developer carrying member is improved.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, there is provided a developer carrying member for carrying a developer for developing an electrostatic latent image formed on an image carrier, and a developing device for storing the developer. An image forming apparatus including a developer storage tank, a supply member that supplies a developer to a developer carrying member, and a layer thickness regulating member that regulates a layer thickness of the developer by thinning the developer on the developer carrying member. In this case, the supply member contains a charge control agent, so that the developer charging property between the supply member and the developer carrying member is increased, and the developer supply property to the developer carrying member is improved.

According to a second aspect of the present invention, the charge polarity of the developer is negative and the charge control agent contained in the supply member is made electron-donating, whereby the negative charge of the developer is reduced. This can be performed effectively, and the supply of the developer to the developer carrier is improved.

According to a third aspect of the invention, the charge polarity of the developer is positive, and the charge control agent contained in the supply member is made electron-accepting. This can be performed effectively, and the supply of the developer to the developer carrier is improved.

According to a fourth aspect of the present invention, there is provided a developer carrying member for carrying a developer for developing an electrostatic latent image formed on an image carrier, a developer storage tank for storing the developer, An image forming apparatus comprising: a supply member that supplies a developer to a developer carrying member; and a layer thickness regulating member that regulates a layer thickness of the developer by thinning the developer on the developer carrying member, The layer thickness regulating member contains a charge controlling agent, whereby the amount of developer and the amount of charge on the developer carrying member are stabilized, and a high quality image can be obtained.

According to the present invention, the charge polarity of the developer is negative and the charge control agent contained in the layer thickness regulating member is made electron-donating. It has an effect that charging can be performed effectively and developer supply to the developer carrier is improved.

According to the present invention, the charge polarity of the developer is positive and the charge control agent contained in the layer thickness regulating member is electron-accepting. Charging can be performed effectively, and the supply of the developer to the developer carrier is improved.

(Embodiment 1) Hereinafter, Embodiment 1 of the present invention will be described. FIG. 1 is a sectional view of an image forming apparatus according to the first embodiment of the present invention, and FIG. 2 is a first embodiment of the present invention.
FIG. 3 is a cross-sectional view around a developing roller in the image forming apparatus of FIG. Since the configuration other than the periphery of the developing roller is the same as that of the conventional image forming apparatus, the same reference numerals are given and the detailed description is omitted.

The photoreceptor 1 is a negatively charged OPC having an aluminum drum as a base material and an organic photoconductor applied in a thin film on the outer peripheral surface. The toner 9 is a non-magnetic, one-component negatively charged toner, which is obtained by uniformly dispersing carbon, wax, a charge control agent, and the like in a polyester resin.

The developing roller 10, which is a developer carrying member,
Using a metal shaft as a base material, a resistance value of 10
This is a single-layer structure in which silicon rubber, which is a conductive elastic member of 6 Ωcm, is formed. A developing bias power supply 14 is connected to a metal shaft of the developing roller 10. This developing roller 10 preferably has a rubber hardness of 30 to 60 degrees,
Further, the surface roughness is preferably 7 μmRz or less because the higher the surface smoothness, the more uniform the formation of a thin toner layer can be achieved. The layer thickness regulating blade 13 is formed by integrally molding a layer thickness regulating member 13b made of urethane rubber at one end of a metal spring plate member 13a.

The toner supply roller 6, which is a developer supply member, is formed by dispersing a charge control agent 29 in a urethane foam having a resistance value of about 106 Ωcm around a metal shaft 6 by about 5% by weight. As the charge control agent 29, an electron donating nigrosine dye is used. The toner supply roller 6 supplies the toner 9 to the developing roller 10 and
It also has a function of scraping off the toner 9 on the developing roller 10 remaining without being developed. A toner supply bias power supply 11 is connected to a metal shaft of the toner supply roller 6 via a protection resistor 12.

The charge control agent 29 is added in an amount of 5% by weight.
Although the amount of addition may be changed according to the characteristics of the toner 9 and the developing roller 10, it is preferably in the range of 0.5 to 10% by weight in order to utilize the characteristics of the charge control agent 29. The charge control agent 29 to be added to the toner supply roller 6 does not need to be a nigrosine dye, but may be a simple substance of an electron donating charge control agent such as an alkoxylated amine, a quaternary ammonium salt, an alkylamide, phosphorus and tungsten. And compounds, molybnate chelate pigments, and the like.

When the toner 9 is positively chargeable, an azo metal-containing complex, an organic complex, a polyolefin chloride, a sulfonylamine of copper phthalocyanine, a metal salt of naphthenic acid, etc., which are electron-accepting charge control agents, are supplied to the toner. Roller 6
May be added.

The transfer unit 22 includes a transfer wire 22a made of a tungsten wire and a metal shield plate 22b. The cleaner unit includes a cleaning blade 26 and a toner collection container 27. The bias voltage value of the developing bias power supply 14 is -300 V, the bias voltage value of the toner supply bias power supply 11 is +300 V, and the resistance value of the protection resistor 12 is 22 MΩ.
It is.

The operation of the image forming apparatus configured as described above will be described. Process speed is 96mm /
sec, the peripheral speed of the developing roller 10 is 192 mm / sec.
Thus, the peripheral speed ratio with respect to the photosensitive member 1 is twice. The layer thickness regulating roller 29 has a linear pressure of 80 g / cm with respect to the developing roller 10.
It is fixed in a state where it touches.

The peripheral speed of the toner supply roller 6 is 132 mm
/ Sec. The rotation directions of the photoconductor 1, the developing roller 10, and the toner supply roller 6 are in the directions of arrows shown in FIG. 1, respectively, and the respective contact portions are in frictional contact.

The photoconductor 1 is uniformly charged to -700 V by the charger 2, and the photoconductor 1 is exposed to an exposure optical system 3 according to an image signal.
, The potential of the unexposed portion becomes -700 V and the potential of the exposed portion becomes about -100 V, forming an electrostatic latent image on the photoreceptor 1. Is done.

After being stirred and conveyed by the toner stirring member 8, the toner 9 is developed by the developing roller 10 and the toner supply roller 6 by the developing roller 10 and the toner supply roller 6.
The toner 9 supplied and conveyed to the surface of the developing roller 10 is regulated in toner layer thickness by the layer thickness regulating blade 13 and is triboelectrically charged to form a thin layer on the outer peripheral surface of the developing roller 10. Thereafter, the toner 9 is transferred and adhered to a portion of the photoconductor 1 where the electrostatic latent image is formed by a bias voltage applied from the developing bias power supply 14 to visualize the electrostatic latent image.

Next, a corona discharge is caused by applying a voltage of 1 kV to the transfer line 22a made of a tungsten wire, and the toner image on the photosensitive member 1 is transferred onto the recording paper 17. The toner image transferred onto the recording paper 17 is fixed on the recording paper 17 by pressure and heat by a fixing device 25 including a heat roller 23 and a pressure roller 24, and printing is completed.

(Embodiment 2) Hereinafter, Embodiment 2 of the present invention will be described. FIG. 3 is a cross-sectional view of the vicinity of the developing roller in the image forming apparatus according to Embodiment 2 of the present invention. Since the configuration other than the vicinity of the developing roller is the same as that of the image forming apparatus of the first embodiment, the same numbers are given and the detailed description is omitted.

The image forming apparatus according to the second embodiment of the present invention is different from the first embodiment in that a charge controlling agent 29 is added to the layer thickness regulating blade 13 as shown in FIG. The toner 9 is a negatively charged toner, in which a charge controlling agent 29 having an electron donating property of 3% by weight is added to a layer thickness regulating member 13b formed of urethane rubber. An alkoxylated amine was used as a charge control agent.

Note that, similarly to the first embodiment, the charge control agent 2
The addition amount of 9 may be changed in the range of 0.5 to 10% by weight as necessary. The charge controlling agent does not need to be an alkoxylated amine, and may be an electron-donating nigrosine dye, a quaternary ammonium salt, an alkylamide, a simple substance or a compound of phosphorus and tungsten, a molybdate chelate pigment, or the like.

When the toner 9 is positively chargeable, an azo metal-containing complex which is an electron-accepting charge control agent;
An organic complex, a chlorinated polyolefin, a sulfonylamine of copper phthalocyanine, a metal salt of naphthenic acid, or the like may be added to the layer thickness regulating member 13b.

[0034]

As described above, according to the present invention, the chargeability of the developer between the supply member and the developer carrying member is increased by mixing the charge controlling agent into the developer supplying member, and the developer carrying member is provided. The supply of the developer to the developer can be improved, and the occurrence of density unevenness due to a defective supply of the developer can be prevented. Also, by mixing the charge controlling agent into the layer thickness regulating member, the charge of the developer between the developer carrying member and the layer thickness regulating member is promoted, and it is possible to prevent the occurrence of fogging due to the insufficient amount of charge of the developer. it can.

[Brief description of the drawings]

FIG. 1 is a sectional view of an image forming apparatus according to a first embodiment of the present invention;

FIG. 2 is a sectional view around a developing roller in the image forming apparatus according to the first embodiment of the present invention;

FIG. 3 is a sectional view around a developing roller in the image forming apparatus according to the second embodiment of the present invention;

FIG. 4 is a cross-sectional view around a developing roller in a conventional image forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charger 3 Exposure optical system 4 Exposure light beam 5 Developing device 6 Toner supply roller 7 Toner hopper 8 Toner stirring member 9 Toner 10 Developing roller 11 Toner supply bias power supply 12 Protection resistor 13 Layer thickness regulating blade 14 Development bias power supply 15 Blade holder 16 recording paper cassette 17 recording paper 18 paper feed roller 19 transport roller 20 registration roller 21 driven roller 22 transfer unit 23 heat roller 24 pressure roller 25 fixing unit 26 cleaning blade 27 toner collection container 28 static eliminator 29 charge control agent

Claims (6)

[Claims] A developer carrying member for carrying out a development for developing an electrostatic latent image formed on the image carrier; a developer storing tank for storing the developer; and a developer carrying member. An image forming apparatus comprising: a supply member that supplies the developer, and a layer thickness regulating member that regulates the layer thickness of the developer by thinning the developer on the developer carrying member. An image forming apparatus, wherein the supply member includes a charge control agent. 2. The image forming apparatus according to claim 1, wherein the charge polarity of the developer is negative, and the charge control agent contained in the supply member has an electron donating property. 3. The image forming apparatus according to claim 1, wherein the charge polarity of the developer is positive, and the charge control agent contained in the supply member is electron-accepting. 4. A developer carrying member for carrying a developer for developing an electrostatic latent image formed on an image carrier, a developer storage tank for storing the developer, and the developer carrying member. An image forming apparatus comprising: a supply member that supplies the developer, and a layer thickness regulating member that regulates the layer thickness of the developer by thinning the developer on the developer carrying member. An image forming apparatus, wherein the layer thickness regulating member contains a charge control agent. 5. The image forming apparatus according to claim 4, wherein the charge polarity of said developer is negative, and said charge control agent contained in said layer thickness regulating member is electron donating. 6. The image forming apparatus according to claim 4, wherein the charge polarity of the developer is positive, and the charge control agent contained in the layer thickness regulating member is electron-accepting.