JP2001350337A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device equipped with a stirring means capable of eliminating trouble that density irregularity is caused between a part to which developer (toner) is supplied and a part to which it is not supplied due to the difference of the electrification performance and the fluidity between the developer remaining in a developing device and the developer newly supplied from a developer unit when the developer is supplied from the developer unit. SOLUTION: This device is equipped with a paddle 7 capable of stirring the developer supplied to the developing device from a toner cartridge back and forth and right and left with respect to the rotating direction of a developing roller. The attaching angle θof the stirring blade 7a of the paddle 7 being the stirring means is made smaller than the angle of repose in order to secure stirring performance in the shaft direction of the developing roller (vertical direction to the rotating direction).

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 such as an electrophotographic system.

[0002]

2. Description of the Related Art An image forming section of an electrophotographic image forming apparatus comprises a charging device, an exposing device, an image carrier, a developing roller and the like. In the image forming section, an electrostatic latent image is formed on the surface of the image carrier by exposure based on image data, and a visible image is formed by developing the electrostatic latent image by attaching a developer with a developing roller. In general, a non-magnetic one-component contact developing method often used as a developing method is as follows.
The image forming apparatus includes an image forming apparatus in which an image carrier and a developing roller are integrally formed, and a detachable developer unit. Then, the developer (toner) is supplied from the developer unit to the developing device at an appropriate time, and the developer is supplied to the developing roller while being stirred by a stirring means such as a paddle or an agitator. The electrostatic latent image of the body is developed.

[0003]

However, in the conventional paddles and agitators, which are stirring means, the developer is conveyed only in the developing roller rotation direction. Therefore, when the developer is replenished from the developer unit, the difference between the replenished portion and the developer replenished from the developer unit is caused by the difference in chargeability and fluidity of the developer replenished from the developer unit. However, there is a problem that density unevenness occurs in a portion other than the above.

[0004] Therefore, the present invention is based on the difference in charge and fluidity of the developer supplied from the developer unit.
It is an object of the present invention to provide an image forming apparatus capable of eliminating the occurrence of density unevenness between a replenished portion and a portion not replenished.

[0005]

According to the present invention, there is provided an image carrier for carrying an electrostatic latent image, and the electrostatic latent image is visualized by contacting the image carrier with a non-magnetic one-component developer. An image forming apparatus, comprising: a developing roller, a developing roller, and a detachable developer unit, wherein a developer can be supplied from the developer unit to a developing device. A stirring means capable of stirring the developer in the front-rear and left-right directions with respect to the developing roller rotation direction was provided.

According to the present invention, there is provided an image forming apparatus which can eliminate the occurrence of density unevenness between a replenished portion and a non-replenished portion due to a difference in chargeability and fluidity of a developer replenished from a developer unit. it can.

[0007]

DETAILED DESCRIPTION OF THE INVENTION According to the first aspect of the present invention, there is provided an image carrier for carrying an electrostatic latent image, and the electrostatic latent image is made visible by a non-magnetic one-component developer by contacting the image carrier. An image forming apparatus having a developing roller for forming an image and a detachable developer unit, wherein the developer can be supplied from the developer unit to the developing device, wherein the developer is supplied from the developer unit to the developing device. Is provided with a stirring means capable of stirring the front, rear, left and right with respect to the developing roller rotation direction. Further, in the invention according to claim 2, the stirring means has a stirring blade, and the mounting angle of the stirring blade with respect to the rotation direction of the developing roller is smaller than the angle of repose of the developer.

With this configuration, the agitation of the developer remaining in the developing device and the developer replenished from the developer unit can be improved, and the density unevenness can be improved.

An embodiment of the present invention will be described below. FIG. 1 is a sectional view of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view of the stirring means in one embodiment of the present invention, and FIG. 3 is a side view of the stirring means in one embodiment of the present invention.

In FIG. 1, a photosensitive drum 2 as an image carrier is provided rotatably in the direction of an arrow. The following are arranged around the photosensitive drum 2 along the rotation direction. That is, a charging unit 1 for uniformly charging the photosensitive drum 2 is provided, and the photosensitive drum 2 charged by the charging unit 1 is exposed to form an electrostatic latent image. A developing roller 3 for storing a toner 6b as a developer in the downstream developing device and developing an electrostatic latent image with the toner 6b, a toner replenishing roller 5 for replenishing the developing roller 3 with the toner 6b, A blade 4 for regulating the thickness of the toner layer on the developing roller 3 is provided. Further, a paddle 7 which is a stirring means rotatably provided in the direction of the arrow is arranged in the developing device which contains the toner 6b. On the upstream side, there is provided a toner cartridge 8 which is a detachable developer unit containing a toner 6a for replenishment.

Next, the operation will be described. First, the photosensitive drum 2 is uniformly charged by the charging means 1, and the charged photosensitive drum 2 forms an electrostatic latent image on the surface of the photosensitive drum 2 by exposure based on image data.
To form a visible image by applying the toner 6b to develop the electrostatic latent image. By repeating such a process, the toner 6b contained in the developing device is consumed. When a predetermined amount of toner has been reached, replenishment of the toner 6a is started from the toner cartridge 8 arranged on the upstream side, and the replenishment ends when the amount of toner in the developing device reaches a predetermined amount.

In a conventional paddle or agitator, which is a stirring means, when toner is supplied from a toner cartridge, the toner remaining in the developing device and the toner newly supplied from the toner cartridge are changed only in the developing roller rotation direction. Stirring was not possible in the axial direction of the developing roller (perpendicular to the rotation direction). Therefore,
Due to the difference in chargeability and fluidity between the toner remaining in the developing device and the toner newly replenished from the toner cartridge, density unevenness was observed between the replenished portion and the portion that was not. Therefore, conventionally, the toner supply port from the toner cartridge is fully opened to the printing area, and the design is restricted.

However, according to the present invention, in order to improve the density unevenness without such a design limitation, as shown in FIGS. By making an angle θ with respect to the rotation direction of the developing roller, stirring in the axial direction of the developing roller (perpendicular to the rotating direction) is enabled, and the toner 6a supplied from the toner cartridge 8 is moved back and forth with respect to the rotating direction of the developing roller. It was made possible to stir left and right. Here, the mounting angle θ of the stirring blade 7a of the paddle 7 serving as the stirring means is set smaller than the repose angle of the toner in order to secure the stirring property in the axial direction of the developing roller (perpendicular to the rotation direction). There must be. That is, when the angle of repose is larger than the repose angle of the toner 6a, the stirred toner 6a slides down from the stirring blade 7a,
Movement in the developing roller rotation direction is mainly performed, movement in the developing roller axial direction (perpendicular to the rotation direction) is reduced, and much rotation time is required to improve density unevenness.

[0014]

As described above, according to the present invention, the toner remaining in the developing device and the toner replenished from the new toner cartridge are sufficiently stirred to improve the density unevenness without design restrictions. Can be.

[Brief description of the drawings]

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

FIG. 2 is a perspective view of a stirring unit according to the embodiment of the present invention.

FIG. 3 is a side view of the stirring means according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Charging means 2 Photoreceptor drum 3 Developing rollers 6a, 6b Toner 7 Paddle 7a Stirring blade 8 Toner cartridge

Claims (2)

[Claims] An image carrier that carries an electrostatic latent image; a developing roller that contacts the image carrier to visualize the electrostatic latent image with a non-magnetic one-component developer; An image forming apparatus having a developer unit and capable of replenishing developer from the developer unit to a developing device, wherein the developer supplied from the developer unit to the developing device is rotated in a developing roller rotation direction. An image forming apparatus comprising: a stirring means capable of stirring forward, backward, left and right. 2. An image forming apparatus according to claim 1, wherein said stirring means has stirring blades, and an angle of attachment of said stirring blades with respect to a developing roller rotation direction is smaller than a repose angle of the developer. apparatus.