JPH10268638A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong the service life of a developer-layer regulation member by bringing an arbitrary layer-regulation part into contact with a developing roller, by providing such developer-layer regulation member that has a plurality of layer regulation parts, which are selectively brought into contact with the periphery of the developing roller. SOLUTION: The developing device 1 is composed by attaching the developing roller 3, a supply roller 4, which is in contact with the developing roller 3, and the developer-layer regulation member 5 to a developer container, which stores nonmagnetic developer freely rotatably. The shaft 6 composing the base part of the developer-layer regulation member 5 is hexagonal, and the layer regulation parts 5a-5d are arranged on the sides of the shaft 6, one on each. The layer regulation parts 5a-5d are apart from each other, made of an elastic material, and differ from each other in contact pressure to the developing roller 3 per unit area. Therefore, conditions under which developer is electrified can be altered by selecting, from the layer regulation parts, required one, and bringing it into contact with the developing roller 3, thereby altering the contact pressure of the layer regulation part to the developing roller 3 per unit area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an electrophotographic apparatus.

[0002]

2. Description of the Related Art In order to develop an electrostatic latent image formed on the surface of a photoreceptor, as shown in FIG. A developing device that regulates the thickness of a developer layer while charging a non-magnetic developer with a developer layer regulating blade 51 is widely used.

[0003]

In this type of developing device, the developer layer regulating blade 51 is rotated by the rotating developing roller 5.
Because it is pressed against 0, it will wear out if used for a certain period of time,
Alternatively, the filming of the developer proceeds. Filming means that the developer is melted by friction to form a film-like film. The abrasion of the developer layer regulating blade 51 and the progress of filming decrease the amount of charge when the developer is frictionally charged between the developing roller 50 and the developer layer regulating blade 51. This can result in reduced resolution,
A white background rash, which means that the developer (toner) adheres to the white background region, occurs, and the life of the developer layer regulating blade 51 is shortened.

[0004] In forming an image, the image forming area of the photoreceptor differs depending on the size of the designated paper, and the amount of developer consumed differs between the image forming area and the non-image forming area.
Therefore, in the non-image forming area, the amount of the developer adhering to the developing roller 50 increases. For this reason, when used for a long period of time, the end of the developer layer regulating blade 51 pressed against the end of the developing roller 50 corresponding to the non-image forming area is worn, and filming between the two proceeds. Occurs. As described above, when the developer layer regulating blade 51 having abraded or filmed edges is used, it is difficult to perform uniform development when the image forming area is large.

The present invention has been made in view of the above circumstances, and has as its object to improve the life of a developer layer regulating member and obtain a normal image.

[0006]

According to the first aspect of the present invention,
A developer container in which a non-magnetic developer is stored; a developing roller in contact with the outer periphery of the developing roller and rotatably supported by the developer container; and a thickness of the developer layer on the developing roller. And a developer layer regulating member for selecting one of these layer regulating sections and making it contactable with the developing roller. Therefore, it is possible to bring an arbitrary layer regulating portion into contact with the developing roller.

According to a second aspect of the present invention, there is provided a developer container containing a non-magnetic developer, a developing roller rotatably supported by the developer container, and a developing roller which is brought into contact with the outer periphery of the developing roller. A plurality of layer regulating portions for regulating the thickness of the developer layer on the developing roller are provided on a peripheral surface of the shaft, and include a developer layer regulating member which is supported so as to be freely fixed at an arbitrary position in the rotation direction. Therefore, by changing the position of the developer layer regulating member in the rotation direction, it becomes possible to sequentially contact the plurality of layer regulating portions of the developer layer regulating member with the developing roller.

According to a third aspect of the present invention, in the first or second aspect, a developer layer regulating member having a plurality of layer regulating portions having different contact pressures per unit area with respect to the developing roller is provided. Therefore, by selecting a desired layer regulating portion and bringing the layer regulating portion into contact with the developing roller, the contact pressure per unit area of the layer regulating portion with respect to the developing roller changes, so that the charging condition of the developer can be changed.

According to a fourth aspect of the present invention, in the first or second aspect, the contact pressure per unit area of the layer regulating portion with respect to the developing roller is larger in the image forming area than in the non-image forming area. Is set to Therefore, the charge amount of the developer in the image forming area is made higher than the charge amount of the developer in the non-image forming area to improve the image quality, and the wear of the layer regulating portion and the occurrence of filming in the non-image forming area are prevented. Becomes possible.

According to a fifth aspect of the present invention, there is provided a developer container containing a non-magnetic developer, a developing roller rotatably supported by the developer container, and a developing roller which is brought into contact with the outer periphery of the developing roller. A developer layer regulating member that regulates the thickness of the developer layer on the developing roller and that is supported so as to be freely fixed at an arbitrary position in the rotation direction. Therefore, by changing the position of the developer layer regulating member in the rotation direction, it is possible to sequentially change the contact position of the developer layer regulating member with respect to the developing roller.

According to a sixth aspect of the present invention, in the fifth aspect of the invention, the developer layer regulating member is driven to rotate with a predetermined linear velocity difference with respect to the developing roller. Therefore,
The life of the developer layer regulating member is prolonged because the outer periphery thereof is uniformly contacted with the developing roller. Further, it is possible to increase the charge amount of the developer by a frictional force generated by a linear speed difference between the developing roller and the developer layer regulating member.

According to a seventh aspect of the present invention, in the sixth aspect of the invention, the developer layer regulating member is rotationally driven so that the number of revolutions can be changed. Therefore, since the frictional force of the developer layer regulating member with respect to the developing roller changes, the charging condition of the developer can be changed.

[0013]

FIG. 1 shows a first embodiment of the present invention.
It will be described based on. Developing device 1 in the present embodiment
A developing roller 3, a supply roller 4 in contact with the developing roller 3, and a developer layer regulating member 5 are rotatably mounted on a developer container 2 for storing a non-magnetic developer (not shown). It is formed by doing. The shaft 6 constituting the base of the developer layer regulating member 5 has a hexagonal cross section.
The developer layer regulating member 5 has a plurality of layer regulating portions 5a, 5b, 5c, 5d arranged on each side of the shaft 6. In the present embodiment, these layer regulating portions 5a, 5b,
5c and 5d are formed of an elastic material in a state where they are separated from each other, but may be formed in a continuous state. Further, any of the layer regulating portions 5a, 5b, 5c, 5d is selectively brought into contact with the developing roller 3 by changing the rotational position of the shaft 6. The three radii are determined to have the largest semicircular cross-sectional shape. The other layer regulating portion 5b has a semicircular cross section, but has a smaller radius than the layer regulating portion 5a. The layer regulating portion 5c has a cross-sectional shape in which a part of a semicircle is cut. Remaining layer regulation part 5d
Is such that the cross-sectional shape near the end of the shaft 6 (non-image forming area) is double-peaked, and the center is In the (image forming region), the cross-sectional shape is a single mountain shape.

Here, comparing the layer regulating portions 5a and 5b, the contact pressure per unit contact area with the developing roller 3 is larger by the smaller radius of the layer regulating portion 5b. Also,
Comparing the one peak portion (image forming region) and the two peak portions (non-image forming region) of the layer regulating portion 5d, the one peak portion has a smaller contact area with the developing roller 3 per unit area. Large contact pressure.

The layer regulating portions 5a, 5b having a semicircular cross section
When the developer is conveyed toward the developer layer regulating member 5 by the developing roller 3 rotating in the counterclockwise direction, a comparison is made between the layer regulating portion 5c in which a part of the semicircular developer receiving side is cut. The layer regulating portions 5a and 5b having a semicircular cross section
Since the developer is received with a smooth curved surface so as to gradually widen the entrance as the distance from the nip portion to the developing roller 3 increases, the flow of the developer is good. That is, the thickness (conveyance amount) of the developer layer tends to increase. On the other hand, when the developer is received at the cut portion side, the layer regulating portion 5c tends to escape the developer outward and the thickness (conveyance amount) of the developer layer on the developing roller 3 tends to decrease. Become.

In such a configuration, the developer in the developer container 2 is supplied to the developing roller 3 by the supply roller 4, and is further conveyed to the developer layer regulating member 5 by the rotation of the developing roller 3. The developer passes through between any of the layer regulating portions 5 a to 5 d of the agent layer regulating member 5 and the developing roller 3.
At this time, the developer is pressed from any one of the layer regulating portions 5a to 5d and charged by the frictional force, and the thickness of the layer on the developing roller 3 is regulated.

Here, since the developer layer regulating member 5 includes a plurality of (three in this example) layer regulating portions 5a having the same shape, when these layer regulating portions 5a are used as standard specifications. By changing the position of the developer layer regulating member 5 in the rotation direction, one of the plurality of layer regulating portions 5a can be selected and brought into contact with the developing roller 3. In a usage mode in which the used layer regulating portion 5a is frequently changed, the life of one layer regulating portion 5a can be extended. Further, even when a certain layer regulating portion 5a is worn and the next layer regulating portion 5a is brought into contact with the developing roller 3, the life of the developer layer regulating member 5 can be extended.

When the pressing force per unit area against the developing roller 3 is large, the charge amount of the developer increases, and the thickness (conveyance amount) of the developer layer on the developing roller 3 is appropriately regulated. Therefore, it is possible to prevent white background rash and to improve the resolution of an image. Therefore, as described above, the developer layer regulating member 5 has different pressure contact force per unit area with respect to the developing roller 3 depending on the layer regulating section to be used. Therefore, it is better to increase the charge amount of the developer by observing the developing state. If it is determined that it is good, the layer regulating portion 5b having a small radius can be brought into contact with the developing roller 3 instead of the layer regulating portion 5a.

When the image density is low, the layer regulating portion 5 which tends to increase the thickness of the developer layer on the developing roller 3
By bringing c into contact with the developing roller 3, the image density can be increased.

Further, when an image is transferred to a small-size sheet, the image forming area on the photosensitive member 7 is narrowed, and the consumption amount of the developer is different between the image forming area and the non-image forming area. In the present embodiment, one hill portion (a portion where the contact pressure per unit area becomes high) of the layer regulating portion 5 d is brought into contact with the image forming region of the developing roller 3, and the layer regulating portion 5 d contacts the non-image forming region of the developing roller 3. By contacting the two peaks of 5d (portion where the contact pressure per unit area becomes low), the charge amount of the developer is increased in the image forming area and the thickness of the developer layer on the developing roller 3 ( It is possible to appropriately control the amount of conveyance and prevent a white background from being blurred and improve the resolution of an image. Further, in the non-image forming area, the developer adheres to the end of the developing roller 3 as much as the developer is not consumed on the photoreceptor 7, but this portion comes into contact with two ridges having a large contact area of the layer regulating portion 5 d. Therefore, the contact area per unit area can be reduced in that portion. Accordingly, it is possible to prevent abrasion of the developer layer regulating member 5 that comes into contact with the end portion of the developing roller 3 and occurrence of filming, which are conventionally seen.

The shaft 6 of the developer layer regulating member 5 is not limited to a hexagon, but may be another polygonal or cylindrical shaft.

Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as those in the previous embodiment are denoted by the same reference numerals and description thereof is omitted. The developer layer regulating member 9 in the present embodiment has a cylindrical shape, and the shaft 1 protruding from both ends thereof.
Numeral 0 is supported on both sides of the developer container 2 so as to be freely rotatable and freely fixed at an arbitrary position.

Therefore, by changing the position of the developer layer regulating member 9 in the rotation direction, the contact position with respect to the developing roller 3 can be changed sequentially. Thereby, the life of the developer layer regulating member 9 can be extended.

The shaft 10 of the developer layer regulating member 9 is connected by a motor (not shown), and the motor rotates the developer layer regulating member 9 with respect to the developing roller 3 at a predetermined linear velocity difference. Can also. In this case, the outer circumference of the developer layer regulating member 9 can be uniformly contacted with the developing roller 3, so that the life can be extended. Further, the frictional force can be increased by the linear velocity difference between the developing roller 3 and the developer layer regulating member 9 to increase the charge amount of the developer.

Further, the developing roller 3 is rotated by changing the number of rotations of a motor for driving the developer layer regulating member 9.
By changing the linear velocity difference between the developer and the developer layer regulating member 9,
By changing the frictional force of the developer layer regulating member 9 with respect to the developing roller 3, the charging condition of the developer can be freely set.

[0026]

According to the first aspect of the present invention, since a developer layer regulating member having a plurality of layer regulating portions selectively contacting the outer periphery of the developing roller is provided, an arbitrary layer regulating portion can be developed. By contacting the roller, the life of the developer layer regulating member can be extended.

According to the second aspect of the present invention, the plurality of layer regulating portions that are in contact with the outer periphery of the developing roller can freely fix the developer layer regulating member disposed on the peripheral surface of the shaft at an arbitrary position in the rotation direction. The plurality of layer regulating portions of the developer layer regulating member can be sequentially brought into contact with the developing roller by changing the position of the developer layer regulating member in the rotation direction. Therefore, the life of the developer layer regulating member can be extended.

According to the third aspect of the present invention, since a developer layer regulating member having a plurality of layer regulating portions having different contact pressures per unit area with respect to the developing roller is provided, a desired layer regulating portion is selected and developed. By bringing the layer regulating portion into contact with the roller, the contact pressure per unit area of the layer regulating portion can be changed, and the change in the contact pressure can change the charging condition of the developer.

According to the fourth aspect of the present invention, the contact pressure per unit area of the layer regulating portion with respect to the developing roller is set to a larger value in the image forming area than in the non-image forming area. The image quality can be improved by setting the charge amount of the developer in the non-image forming area higher than the charge amount of the developer in the non-image forming area, and also prevents abrasion and filming of the layer regulating portion in the non-image forming area. can do.

According to the fifth aspect of the present invention, since the developer layer regulating member is provided so as to be freely fixed at an arbitrary position in the rotation direction, the contact position of the developer layer regulating member with respect to the developing roller is sequentially changed. be able to. Therefore, the life of the developer layer regulating member can be extended.

According to the sixth aspect of the invention, the developer layer regulating member is driven to rotate with a predetermined linear velocity difference with respect to the developing roller. Therefore, since the outer periphery of the developer layer regulating member can be uniformly contacted with the developing roller,
The life of the developer layer regulating member can be extended. Further, the charge amount of the developer can be increased.

According to the seventh aspect of the invention, the developer layer regulating member is rotatably driven so that the number of rotations can be changed, so that the frictional force of the developer layer regulating member with respect to the developing roller is changed, thereby In addition, the charging condition of the developer can be freely changed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional side view showing a second embodiment of the present invention.

FIG. 3 is a side view showing a relationship between a conventional developing roller and a developer layer regulating blade.

[Explanation of symbols]

 Reference Signs List 2 developer container 3 developing roller 6 shaft 5 developer layer regulating member 5a to 5d layer regulating section 9 developer layer regulating member

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuhisa Takeda 570 Ohito, Oni-cho, Tata-gun, Shizuoka Prefecture Inside the Tech Ohi Works, Inc.

Claims (7)

[Claims] 1. A developer container containing a non-magnetic developer, a developing roller rotatably supported by the developer container, and a developer on the developing roller being in contact with an outer periphery of the developing roller. A plurality of layer regulating portions that regulate the thickness of the layer, and a developer layer regulating member that selects one of these layer regulating portions and makes the layer contactable with the developing roller. Developing device. 2. A developer container for storing a non-magnetic developer, a developing roller rotatably supported by the developer container, and a developer on the developing roller which is in contact with the outer periphery of the developing roller. A plurality of layer regulating portions for regulating the thickness of the layer are provided on the peripheral surface of the shaft, and the developer layer regulating member is supported so as to be freely fixed at an arbitrary position in the rotational direction. . 3. The developing device according to claim 1, further comprising a developer layer regulating member having a plurality of layer regulating portions having different contact pressures per unit area with respect to the developing roller. 4. The image forming apparatus according to claim 1, wherein the contact pressure per unit area of the layer regulating portion with respect to the developing roller is set to be larger in the image forming area than in the non-image forming area. Developing device. 5. A developer container for storing a non-magnetic developer, a developing roller rotatably supported by the developer container, and a developer on the developing roller which is in contact with an outer periphery of the developing roller. A developer layer regulating member which regulates the thickness of the layer and is supported so as to be freely fixed at an arbitrary position in the rotation direction. 6. The developing device according to claim 5, wherein the developer layer regulating member is driven to rotate with a predetermined linear velocity difference with respect to the developing roller. 7. The developing device according to claim 6, wherein the developer layer regulating member is rotationally driven so that the number of revolutions can be changed.