JPH0519610A - Developing device for electrophotographic device - Google Patents

Abstract

(57) [Abstract] [Purpose] A developing device of an electrophotographic apparatus, in which an electrostatic latent image is developed by a developer charged by stirring, and a uniform amount having no volume unevenness with respect to a developing roller is provided. An object of the present invention is to provide a developing device of an electrophotographic apparatus, which can supply a developer and can perform high-quality development without density unevenness. [Structure] To supply the developer 100 conveyed near the developing roller 50 by the developer agitating and conveying means 41, 42 to the developing roller 50, the developer 100 is driven when the developer supplying roller 52 is rotationally driven. Developer supply roller 52
The developer supply roller 52 is formed in a shape that allows the developer supply roller 52 to be moved in a direction parallel to the rotation direction and the rotation axis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for an electrophotographic apparatus, which develops an electrostatic latent image with a developer charged by stirring.

In an electrophotographic apparatus, a developer is generally charged in order to develop an electrostatic latent image. In a so-called two-component developing method which uses a toner and a carrier as the developer, the developer is agitated. It is frictionally charged by.

[0003]

2. Description of the Related Art FIG. 7 shows a developing device for a conventional electrophotographic apparatus, in which 91 and 92 are elongated rod-shaped shafts 91a,
The first and second rotary screws 92a each have a continuous spiral blade projectingly provided thereon, and are driven to rotate relatively in opposite directions.

The toner is supplied from a hopper (not shown) to the first rotary screw 91, and is carried together with the carrier in the direction perpendicular to the paper surface while being stirred by the first rotary screw 91.

The developer 100 reaching the end portion of the first rotating screw 91 is conveyed in the opposite direction to the first rotating screw 91 while being agitated by the second rotating screw 92, and again at the end portion thereof. It is pushed to the side of the first rotary screw 91 and circulates. The developer 100 is triboelectrically charged by this movement.

A part of the developer 100 that circulates moves to the second part.
While being agitated by the developer supply roller 95 that is pushed out to the side of the rotary screw 92, has four flat blades protruding in the axial direction as shown in FIG. , On the surface of the developing roller 96.

The developing roller 96 is formed such that a sleeve 96b is fitted on the outside of a magnetized magnet roller 96a and one of the sleeves is driven to rotate.
Then, the charged toner supplied to the surface of the developing roller 96 is conveyed to the developing section 98 after being made to have a constant layer thickness by the layer thickness regulating blade 97 for regulating the layer thickness of the toner. To develop the electrostatic latent image of. 99
Is a developer peeling blade for peeling the developer 100, which has not been used for development and remains on the surface of the developing roller 96 and whose toner concentration is lowered.

[0008]

FIG. 9 shows the first and the second.
The state of the developer 100 conveyed by the rotating screws 91 and 92 is shown. The developer 100 is the developer 100 between the blades of the rotary screws 91 and 92.
In this case, the unevenness of volume occurs in which a small amount is accumulated in the front part and a large amount is accumulated in the rear part in the conveying direction, and the developer 100 in such a state is given to the developer supply roller 95.

On the other hand, the developer supply roller 95 rotates about the axis to supply the developer 100 to the developing roller 96. The blades of the developer supply roller 95 are formed in a flat plate shape parallel to the axis, and Since the developer 100 is only moved in the rotation direction, the unevenness of the volume of the developer 100 given by the rotary screws 91 and 92 appears almost as it is in the developer 100 supplied to the developing roller 96.

As a result, conventionally, the amount of the developer 100 supplied to the developing section 98 is uneven in the width direction, and the developer 100
The areas where the amount of developer is large have a high development density, and the areas where the amount of the developer 100 is small are so low that the density of printing is uneven.

Therefore, according to the present invention, it is possible to supply a uniform amount of developer to the developing roller without unevenness in volume,
It is an object of the present invention to provide a developing device of an electrophotographic apparatus capable of performing high quality development without density unevenness.

[0012]

To achieve the above object, the developing device of the electrophotographic apparatus of the present invention is, as shown in FIG. 1 for explaining an embodiment, a developing device which is charged by stirring. A developing roller 50 that conveys the developer 100 to a developing unit 60 for developing an electrostatic latent image;
0 for transporting 0 to the vicinity of the developing roller 50 while stirring, and the developing roller 50 by the developer stirring transporting means 41, 42.
In a developing device of an electrophotographic apparatus having a developer supply roller 52 that is rotationally driven around an axis so as to supply the developer 100 that has been conveyed in the vicinity of the developer supply roller 52 to the developer roller 50. The developer supply roller 52 is formed in a shape that allows the developer 100 to move in a direction parallel to the rotation direction and the rotation axis of the developer supply roller 52 when driven to rotate.

The developer supply roller 52 may have spiral screw-shaped blades, and the developer supply roller 52 has a plurality of discs or elliptical plates perpendicular to the axis. You may have the blade | wing which inclined in the direction which is not and projected.

[0014]

When the developer supply roller 52 is rotationally driven, the developer 100 is agitated so that the developer 100 is moved not only in the rotation direction of the developer supply roller 52 but also in the direction parallel to the rotation axis. The uneven volume is eliminated.

[0015]

Embodiments will be described with reference to the drawings. Figure 2
1 shows a laser beam printer to which the present invention is applied.
However, the present invention can be applied to a copying machine, a facsimile device, and other electrophotographic devices.

In FIG. 2, around the photosensitive drum 1 rotating in the direction of the arrow, a charging device 2, an exposing device 3, a developing device 4,
A transfer unit 5, a charge eliminating lamp 6 and a cleaner 7 are arranged, and the surface of the photosensitive drum 1 is first negatively charged by the corona discharge of the charger 2.

Next, when the surface of the photosensitive drum 1 is irradiated with light according to the image to be recorded, the potential of the exposed portion is lowered and an electrostatic latent image is formed on the surface of the photosensitive drum 1. To be done. When this latent image area passes through the developing device 4, negatively charged toner adheres to it and development is performed.

On the other hand, the paper 8 on which the image is printed is fed one by one to the position where it comes into contact with the toner image formed on the photosensitive drum 1 by the action of the pick roller 9 and the standby roller 10. The transfer unit 5 is installed on the back side of the sheet 8 below the photosensitive drum 1 so as to give a positive charge to the sheet 8. Therefore, the toner image formed on the surface of the photosensitive drum 1 is attracted by the positive charges of the paper 8 and transferred to it.

The paper 8 on which the toner image is transferred is fixed to the fixing device 1.
The toner image is fixed on the sheet 8 by heat and pressure by being sandwiched between the heat roller 12 forming part 1 and the rubber roller 13 pressed and rotated by the heat roller 12.

The surface of the photosensitive drum 1 on which the toner has been transferred to the paper 8 is destaticized by the destaticizing lamp 6, and the residual toner is cleaned by the cleaner 7 to return to the initial state.
It is charged again by the charger 2.

FIG. 1 is a side sectional view of the developing device 4 described above, and FIG. 3 is a plan sectional view thereof. In the figure, reference numerals 41 and 42 denote first and second rotary screws of the same shape in which continuous spiral blades are projectingly provided on slender rod-shaped shafts 41a and 42a, and are rotatably provided in the housing 40. Has been. The gears 43 and 44 fixed to the ends of the shafts 41a and 42a mesh with each other, so that the first and second rotary screws 41 and 42 rotate relatively in opposite directions.

Further, the toner drops from a hopper (not shown) to the first rotating screw 41, and the toner is charged by being stirred there together with the carrier.
In addition, between the first and second rotary screws 41, 42,
Although it is partitioned by a partition wall 48 which is a part of the housing 40, the partition wall 48 is not formed at both ends. Therefore, the toner supplied to the first rotating screw 41 is
While being charged together with the carrier by the rotation of both rotary screws 41 and 42 and being frictionally charged, arrows E and F in FIG.
As shown in FIG. 3, the rotating screws 41 and 42 are conveyed in the axial direction and circulate.

As shown in FIG. 1, a developing roller 50 is arranged in a chamber formed on the side of the second rotary screw 42. The developing roller 50 is formed by fitting a sleeve 50b that is driven to rotate around the outer circumference of a magnetized magnet roller 50a.

The housing 40 has a large opening between the second rotary screw 42 and the developing roller 50. Therefore, the developer 100 which is conveyed while being stirred by the second rotating screw 42 is pushed laterally from the developer outlet portion 49 toward the developing roller 50.

Second rotating screw 42 and developing roller 5
Between 0 and 0, a developer supply roller 52 that is driven to rotate around an axis so as to supply the developer 100, which has been conveyed in the vicinity of the development roller 50, to the development roller 50 is provided.

As shown in FIG. 4, the developer supply roller 52 includes first and second rotating screws 41 and 42.
Similarly to the above, a continuous rod-shaped shaft 53a is formed in a screw shape in which continuous spiral blades 53 are provided in a projecting manner, and the gear mechanism 54 allows the first and second rotary screws 4 to rotate.
1, 42 and the developing roller 50 are driven to rotate,
The developer 100 extruded from the developer outlet 49 by the second rotating screw 42 is supplied to the developing roller 50 while being stirred.

At this time, since the developer supply roller 52 is formed in a screw shape, the developer 100 is not only moved in the rotation direction by the developer supply roller 52 which is rotationally driven, but at the same time, The developer supply roller 52 is also moved in a direction parallel to the axis and agitated.

Therefore, even if the developer 100 supplied to the developer supply roller 52 has the uneven volume as shown in FIG.
When the toner is sent to the developing roller 50, the unevenness of the volume of the developer 100 is eliminated, and a substantially uniform amount of the developer 100 is supplied to the developing roller 50 over the entire width.

The charged developer 100 thus supplied to the surface of the developing roller 50 is attracted by the magnetic force to the surface of the developing roller 50 and conveyed. And the developer 10
The layer thickness regulating blade 56 for regulating the layer thickness of 0 makes the layer thickness constant and conveys it to the developing section 60, where the electrostatic latent image on the photosensitive drum 1 is developed. In FIG.
Reference numeral 58 denotes a developer peeling blade for peeling off the developer 100 that is not used for development and remains on the surface of the developing roller 50.

The present invention is not limited to the above-described embodiment. For example, the developer supply roller 52 moves the developer around the rotation axis thereof and in a direction parallel to the rotation axis to cause unevenness of the volume of the developer. However, there are various embodiments of the shape.

FIG. 5 shows such a developer supply roller 252.
In the second embodiment of the present invention, a plurality of discs 253 inclined at an angle of 30 degrees with respect to the direction perpendicular to the rotation axis 252a are provided at intervals, and the discs 253 have a V of a 120 degree included angle. The letter-shaped notches 254 are formed by alternately shifting the directions by 180 degrees.

FIG. 6 shows a third embodiment of the developer supply roller 352. Every other elliptical plates 353 are arranged so that they are concentric circles when viewed from the axial direction of the rotating shaft 352a. It is provided in such a manner that it is inclined in the opposite direction and protrudes from the rotary shaft 352a in a V shape.

Also in the second and third embodiments formed in this way, the developer supply roller is connected to the rotary shafts 252a and 252a.
By rotating about 52a, the developer is stirred while moving around the rotation axis and in a direction parallel to the axis, and uneven volume of the developer supplied to the developing roller 50 is eliminated.

[0034]

According to the developing device of the electrophotographic apparatus of the present invention, by rotating and driving the developer supply roller, the developer moves in the direction of rotation and in the direction parallel to the axis and is agitated. Even if the developer supplied from the agent agitating / conveying means to the developer supply roller has unevenness in volume, it is possible to supply a uniform amount of developer to the developing roller without unevenness in volume. High-quality development can be performed without unevenness.

[Brief description of drawings]

FIG. 1 is a side sectional view of a first embodiment.

FIG. 2 is a configuration diagram of a printer according to a first embodiment.

FIG. 3 is a plan sectional view of the first embodiment.

FIG. 4 is a perspective view of a developer supply roller according to the first embodiment.

FIG. 5 is a perspective view of a developer supply roller according to a second embodiment.

FIG. 6 is a perspective view of a developer supply roller according to a third embodiment.

FIG. 7 is a side sectional view of a conventional example.

FIG. 8 is a perspective view of a conventional developer supply roller.

FIG. 9 is an explanatory diagram of occurrence of uneven volume of the developer.

[Explanation of symbols]

41 Rotating screw (developer stirring and conveying means) 42 rotary screw (developer stirring and conveying means) 50 developing roller 52 developer supply roller 60 Development Department 100 developer

Claims (3)

[Claims] 1. A developer (1) which is charged by stirring
00) to a developing unit (60) for developing the electrostatic latent image, and to convey the developer (100) to the vicinity of the developing roller (50) while stirring. Developer stirring and conveying means (41, 42) and the developer (10) conveyed near the developing roller (50) by the developer stirring and conveying means (41, 42).
0) is supplied to the developing roller (50), and a developer supplying roller (52) which is rotationally driven around an axis is provided. In the developing device of the electrophotographic apparatus, the developer supplying roller (52) is rotationally driven. The developer supply roller (52) is formed in a shape that allows the developer (100) to move in the rotation direction of the developer supply roller (52) and in the direction parallel to the rotation axis when the above is performed. Developing device for electrophotographic device. 2. The developing device for an electrophotographic apparatus according to claim 1, wherein the developer supply roller (52) has a spiral screw-shaped blade. 3. The electrophotographic apparatus according to claim 1, wherein the developer supply roller (52) has blades formed by projecting a plurality of discs or elliptical plates in a direction not perpendicular to the axis. Developing device.