JP3321264B2 - Developing device - Google Patents

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 for an image forming apparatus or the like.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Publication No. 4-80390 discloses an apparatus for forming an extremely thin developer layer on a developing roller which supports and transports a developer on the surface. There was something.

[0003]

However, the conventional developing device has an elastic blade 42 for pressing the surface of the developing roller 41 in order to reduce the thickness of the developer layer, as shown in FIG. In this structure, one end of the elastic blade 42 is fixed to the front frame 45 by the tightening force of a plurality of screws 44 via the blade holder 43. Therefore, there is a possibility that the elastic blade 42 around the screw 44 may be distorted by the tightening force of the screw 44.

When the elastic blade 42 is distorted, the contact portion of the elastic blade 42 with the developing roller 41 is also distorted due to the influence, and as a result, the flatness of the contact portion is deteriorated and the surface of the developing roller 41 is deteriorated. Since the thickness of the developer layer formed on the recording medium becomes uneven and the print quality is reduced,
An apparatus for forming a thin layer of a developer having a uniform thickness on the surface of the developer has been desired.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a developing device, comprising: a developing roller for supporting and transporting a developer on a surface thereof; and a beam arranged in parallel with a central axis around which the developing roller rotates. and Jo support means, and the elastic blade for pressing a central axis parallel to the developing roller surface of the deformed current image roller as a fulcrum of the beam-like support means, and a locking means for locking the one end of the elastic blade is provided, The beam-shaped support means is a locking means.
One end of the elastic blade locked by the
Press the elastic blade between the other end in contact with
It was made.

[0006]

According to the present invention, the elastic blade is deformed around the beam-shaped support means arranged in parallel with the central axis of the developing roller to press the surface of the developing roller. The surface of the developing roller can be pressed by a uniform pressing force over the entire contact portion without deteriorating the flatness of the contact portion.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic side sectional view showing a developing device according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a developing device main body, and a housing of the developing device 1 is constituted by a frame 2 and a cover 3. 1a is a cartridge storage section for storing a developer cartridge (not shown) containing a developer such as toner, and 1b is a developer storage section for storing a developer supplied from the developer cartridge attached to the cartridge storage section 1a. The hopper. Reference numeral 4 denotes a photosensitive drum that forms an electrostatic latent image on the surface, and reference numeral 5 denotes a developing roller that supports a developer on the surface and supplies the developer to the electrostatic latent image on the photosensitive drum 4 to develop the electrostatic latent image. It is. Reference numeral 6 denotes a sponge roller for supplying a developer to the developing roller 5 ,
It is formed by the blowing agent.

Reference numeral 9 denotes an elastic blade made of a material having elasticity. As shown in the drawing, one end of the elastic blade 9 is fixed by contacting one end of the elastic blade 9 using the cover 3 as a locking means. The bent free end 9 a is pressed against the outer peripheral surface of the developing roller 5 in parallel with the central axis of the developing roller 5. Reference numeral 10 denotes an L-shaped beam, which is fixed to a pair of left and right side frames 7 and 8 fixed to the frame 2 and the cover 3 at both ends thereof, and is disposed in parallel with the central axis of the developing roller 5. Elastic blade 9 as means
Plays the role of a fulcrum for flexing.

The photosensitive drum 4 and the developing roller 5 are rotatably supported by the side frames 7 and 8.
Is rotatably supported by the frame 2. The photosensitive drum 4, the developing roller 5, and the sponge roller 6 are connected by a gear train (not shown). When the photosensitive drum 4 rotates in the direction of arrow A by the power transmitted from the image forming apparatus, the developing roller 5 The sponge roller 6 rotates in the direction of arrow C. The sponge roller 6 supplies the developer to the surface of the developing roller 5 by this rotation. The developer supplied from the sponge roller 6 and supported on the surface of the developing roller 5 is made into a uniform thin layer of the developer by an elastic blade 9 that presses the surface of the developing roller 5, and is supplied to the photosensitive drum 4. Is done.

FIG. 2 is a perspective view showing the elastic blade of the present invention. As shown in FIG. 2, one free end 9a of the elastic blade 9 is bent at a substantially right angle, and a pair of left and right shoulders 9b and 9c are provided on the opposite end 9h, and the shoulders 9b and 9c are provided. Notches 9f and 9g are provided inside the front end portions 9d and 9e.

Next, the mounting state of the elastic blade to the developing device will be described with reference to FIGS. FIG. 3 is a perspective view showing the support structure of the elastic blade, and FIG. 4 is an enlarged sectional view from the side showing the support structure of the elastic blade.

The side frames 7 and 8 have horizontal planes 7a and 8a arranged at a predetermined distance in the vertical direction from the rotation center of the developing roller 5, and a predetermined distance in the horizontal direction from the rotation center of the developing roller 5. Vertical surfaces 7b, 8b
V-shaped grooves 7c and 8c. The L-shaped beam 10 has its both ends fixed to the side frames 7 and 8, respectively. At this time, the end face 10a of the L-shaped beam 10 is
Are brought into contact with the horizontal surfaces 7a and 8a, and the side surface 10b is
b, 8b.

The elastic blade 9 is attached by placing the shoulders 9b and 9c on the horizontal surfaces 7a and 8a of the side frame with the free end 9a abutting on the surface of the developing roller 5, and then putting the cover 3 on. This is performed by fixing to the frame 2. Therefore, the elastic blade 9 can be added without deteriorating the assemblability. Here, the shoulder portions 9b, 9c are connected to the horizontal surfaces 7a, 8a of the side frames.
When placed on the upper side, the elastic blade 9 is located in a state shown by a two-dot chain line in FIG. When the cover 3 is assembled, the end 9h of the elastic blade 9 comes into contact with the inner surface of the cover 3, and the elastic blade 9 is supported by the edge 10c of the L-shaped beam 10 in a direction indicated by a solid line in FIG. It is deformed to the position shown. The amount of deformation at this time is within the elastic limit of the elastic blade 9, and the free end 9 a presses the surface of the developing roller 5 in parallel with the rotation center of the developing roller 5 by the repulsive force.

By fixing the cover 3, the elastic blade 9 is supported by the edge 10c, and the end 9h is locked to the cover 3 by using the edge 10c as a fulcrum. Accordingly, the engagement point of the end portion 9h of the elastic blade 9 and the contact point with the edge 10c are fixed, so that the contact angle between the elastic blade 9 and the developing roller 5 and the developing roller 5 of the elastic blade 9 The pressing force is kept constant. Further, since the elastic blade 9 is deformed with the entire edge of the edge 10c of the L-shaped beam 10 as a fulcrum, the pressing force at the contact portion between the elastic blade 9 and the developing roller 5 becomes uniform over the entire contact portion. Therefore, the developer layer supported on the developing roller 5 can be uniformly thinned.

FIG. 5 is a schematic sectional view of an image forming apparatus using the developing device according to the present invention. In FIG. 5, reference numeral 20 denotes an image forming apparatus main body, and reference numeral 1 denotes a developing device used in the image forming apparatus 20, and a developer cartridge 21 in which a developer such as toner is stored is mounted.

A detachable paper cassette 22 is mounted below the image forming apparatus 20 from the side of the apparatus. The paper cassette 22 stores the paper 23 for printing inside, and the paper 23 is fed out in the direction of arrow E by the paper feed roller 24. The developing device 1 forms an image with a developer on the surface of the developing roller 5. The fed sheet 23 is conveyed by a registration roller 25, and an image formed by a developer on the surface of the developing roller 5 is transferred by a charge roller 26. The sheet 23 on which the image has been transferred is fixed to the fixing roller 2.
7, and is discharged to the stacker 20a by the discharge rollers 28 and 29.

Next, a second embodiment of the present invention will be described.
FIG. 6 is an enlarged cross-sectional view from the side showing the mounting state of the elastic blade according to the second embodiment of the present invention. The same components as those of the first embodiment are denoted by the same reference numerals.

As shown in FIG. 6, in the second embodiment of the present invention, the end 9h of the elastic blade 9 is attached to the cover 30.
Is provided. Stopper 31
Are formed so as to support the entire edge of the end 9 h in parallel with the central axis of the developing roller 5. The stopper 31 is configured to be slidable in the direction of arrow F along the groove 30 a of the cover 30, and the position of the stopper 31 is adjusted by a pair of left and right adjustment screws 32 provided near both ends of the cover 30. can do.

The elastic blade 9 is mounted by placing the shoulders 9b and 9c on the horizontal surfaces 7a and 8a of the side frame with the free end 9a in contact with the surface of the developing roller 5, and then moving the end 9h. The stopper 3 against the cover 3
0 is fixed to the frame 2. Since the fixing point of the elastic blade 9 and the contact point with the edge 10c are fixed by the fixation of the cover 30, the contact angle between the elastic blade 9 and the developing roller 5, and the development of the elastic blade 9 The pressing force on the roller 5 is kept constant.

In the second embodiment, in the state described above,
The stopper 31 can be moved in the direction of arrow F by the adjusting screw 32. That is, it is possible to move the end 9h of the elastic blade 9 abutted on the stopper 31 around the edge 10c as a fulcrum, and to adjust the pressing force of the elastic blade 9 against the developing roller 5. it can.
Therefore, the pressing force of the elastic blade 9 on the developing roller 5 is changed based on the result of the completion of the assembly of the developing device, mounting on the image forming apparatus, and printing, so that the developer layer on the developing roller 5 is changed. Can be adjusted in thickness. At this time, in order to move the elastic blade 9 over the entire edge of the end 9h with the entire edge of the edge 10c as a fulcrum, the pressing force at the contact portion between the elastic blade 9 and the developing roller 5 is increased over the entire contact portion. It can be adjusted while keeping it constantly uniform.

[0021]

As described in detail above, according to the present invention, the elastic blade is arranged parallel to the central axis of the developing roller.
The beam is deformed with the beam-shaped support
By being pressed by the support means, it becomes possible to press the surface of the developing roller with a uniform pressing force over the entire contact point between the elastic blade and the developing roller. It is possible to provide a developing device capable of forming a uniform thinned developer layer, eliminating printing unevenness, and stably obtaining high print quality.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view from the side showing a developing device according to a first embodiment of the present invention.

FIG. 2 is a perspective view of an elastic blade according to the present invention.

FIG. 3 is a perspective view showing a support structure of an elastic blade.

FIG. 4 is an enlarged sectional view from the side showing a support structure of the elastic blade.

FIG. 5 is a schematic sectional view of an image forming apparatus using the developing device according to the present invention.

FIG. 6 is a schematic side sectional view showing a developing device according to a second embodiment of the present invention.

FIG. 7 is a perspective view showing a conventional developing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Developing device 2 Frame 3 Cover 5 Developing roller 7 Side frame 8 Side frame 9 Elastic blade 10 L-shaped beam

Claims (2)

(57) [Claims] And 1. A developing roller for supporting and transferring the developing agent to the surface, a central axis and parallel to beam-shaped supporting <br/> lifting means of said developing roller, the supporting point the beam-shaped supporting means An elastic blade that deforms and presses the surface of the developing roller in parallel with the central axis of the developing roller; and a locking unit that is formed of a member different from the beam-shaped support unit and locks one end of the elastic blade. The beam-shaped support means is locked by the locking means
Contact one end of the elastic blade with the developing roller.
A developing device that presses the elastic blade between itself and the other end of the developing device. 2. The developing device according to claim 1, further comprising a moving unit that moves the locking unit in a direction in which a deformation amount of the elastic blade is changed.