JP3093377B2 - Developing device for electrophotographic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic system (a system in which an image formed on a photoreceptor is transferred to a sheet for recording) using a laser, such as a printer, a copying machine, and a facsimile. The present invention can be applied to an electrophotographic apparatus for performing recording on a sheet. More specifically, the invention relates to a developing device in such an electrophotographic apparatus, which applies a toner with a developing roller to visualize a latent image on a photoconductor.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 6, a developing device such as a laser printer is provided with a developing roller 1 having a thin layer blade 2 having a tip 2a contacting from below. There was something. Then, the tip 2a is pressed with a constant pressure to scrape off excess toner-3, and the developing roller 1
Is thinned to a certain thickness with a thin blade 2 and the thinned toner 3 is attached to a photoreceptor to visualize a latent image on the photoreceptor. Was supposed to.

[0003]

However, in the above-mentioned developing device, the toner 3 scraped off at the tip 2a of the thin blade 2 adheres to the lower surface of the thin blade 2 and thereafter. Subsequently, the thin blade 2 is pushed by the scraped toner 3 and falls while moving along the lower surface of the thin blade 2. For example, a partition wall 4 provided below the tip of the thin blade 2
a, and accumulates in the lower portion A of the thin layer blade 2, and the accumulated toner 3 pushes up the thin layer blade 2 to cause the developing roller 1 to rise.
Therefore, the thickness of the toner layer is not constant because the pressure applied to the laser printer is changed, and there is a problem that the laser printer causes an image defect.

It is an object of the present invention to provide a laser printer and the like which have a toner blade scraped off by a thin blade.
In the bottom of the thin blade.

[0005]

For Means for Solving the Problems] As a, the first aspect of the present invention, for example as in the following illustrated examples, thin
The layer blade 38 is counted with respect to the rotation of the developing roller 36.
And the leading end 38a is positioned in the developing row.
In the developing device of the electrophotographic apparatus, which is pressed against the roller 36 from below , a toner blocking member 42 is provided on the lower surface of the tip 38a of the thin layer blade 38, and the toner blocking member 42 is provided .
Do not tilt the damming surface 42a so that it faces downward.
That, characterized in that.

[0006]

According to a second aspect of the present invention, in the developing device 14 of the first aspect of the present invention, the toner damping member 42 is made flexible as in the following illustrated embodiment. It is made of rich materials.

[0008]

According to the first aspect of the present invention, the toner 46 which is scraped off from the developing roller 36 and tries to enter along the lower surface of the thin layer blade 38 below the thin layer blade 38 is blocked by the toner blocking member 42. It is dropped Te, the dam
Smoothly moving down along the surface 42a
Drop from the door 38.

[0009]

Further, in the invention according to claim 2, toner dam member 42 does not deform the thin layer blade 38 be deformation depending on such temperature changes.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 5 is a schematic diagram showing the overall configuration of a laser printer having a developing device according to an embodiment of the present invention. What is indicated by reference numeral 10 in the drawing is the apparatus main body. The apparatus main body 10 includes an upper structure 10a and a lower structure 10b,
The upper structure 10a is attached to the lower structure 10b by a shaft 11 so as to be openable and closable. In the apparatus main body 10, a belt-shaped photoconductor 12 is provided substantially at the center. Around the photoreceptor 12, a charger 13, a developing unit 14, a transfer unit 15, and a cleaning unit 16 are arranged in this order in the driving direction indicated by the arrow. An optical writer 18 is disposed below the charger 13 and the cleaning device 16, and a sheet cassette 19 is disposed obliquely above the developing device 14.

The sheet fed from the paper feed cassette 19 by the paper feed roller 20 is conveyed to the upper side of the photosensitive member 12 at a timing by a pair of registration rollers 21. The photoconductor 12 is driven in a counterclockwise direction as indicated by an arrow. At this time, the surface of the photoconductor 12 is uniformly charged by the charger 13, and the photoreceptor 12 is irradiated with the laser beam from the optical writer 18 to rest on the photoconductor 12. An electrostatic latent image is formed. This latent image is stored in the developing device 1
When passing through No. 4, a visible image is formed by the toner. Then, this visible image is transferred by the transfer device 15 to the lower surface of the sheet conveyed above the photoconductor 12. The transcribed sheet
Is transported to the fixing device 17 by being guided by the transport guide 23,
Fix the visible image. The sheet exiting the fixing device 17 is further conveyed to a sheet discharge section 25 by a sheet discharge roller 24, guided by a sheet discharge guide 26, and stacked on a sheet discharge tray 27.

The above-mentioned developing unit 14 comprises a developing unit main body 30 and a toner cartridge 31 as shown in FIG. The developing device main body 30 has a developing frame 32. A developing chamber 33 is provided in the developing frame 32. A developing roller window 34 is provided on the photoconductor 12 side of the developing chamber 33.
And a toner supply port 35 is provided on the side opposite to the developing roller window 34. A developing roller 36 is provided in the developing chamber 33.
The toner replenishing member 37, the thin layer blade 38, and the static elimination brush 39 are attached. The tips of the thin layer blade 38 and the charge removing brush 39 are brought into contact with the surface of the developing roller 36, respectively. In this embodiment, the developing device body 30
In addition, the above-described charger 13 and an optical component 40 that transmits laser light are also attached.

Then, the thin layer blade 38 is
And attached to the developing frame 32, and its tip 38
a is pressed against the developing roller 36 in a counter direction with respect to the rotation of the developing roller 36 from below. As shown in FIG. 2, a toner damming member 42 having a rectangular cross section is provided on the lower surface of the tip 38a of the thin blade 38, as shown in FIG. The toner damming member 42 is made of a material such as a sponge which does not deform the thin blade 38 due to a difference in expansion coefficient due to a change in temperature or a change with time when the thin blade 38 is attached to the thin blade 38. . Then, one surface in the longitudinal direction of the toner damming member 42 is attached to the lower surface of the thin layer blade 38 by the elastic double-sided tape 43, and the other surface of the toner damming member 42 is perpendicular to the surface. In this case, the surface on the tip side of the thin blade 38 is defined as a damming surface 42a. As shown in FIG. 1, a partition wall 32a rising from the developing frame 32 is provided below the leading end 38a of the thin layer blade 38 to prevent toner leakage from the developing chamber 33. .

On the other hand, the toner cartridge 31 is provided with a toner chamber 31b for storing toner. Toner room 31b
The opening 3 for supplying the toner to the developing device main body 30 is provided.
1a is provided, and the agitator 44 is rotatably supported by the support shaft 44a. Further, the toner-end detection sensor 4
5 is provided on the wall surface. Then, the toner cartridge 31 is attached to the developing device main body 30, and the flanges 33a and 31c of each other.
The developing unit 14 is constituted by integrally connecting the developing roller 14 by heat welding or the like, assembled to the apparatus main body 10, and the developing roller 36 is connected to the developing roller.
The photosensitive member 12 is pressed through the window 34.

When the agitator 44 rotates clockwise as indicated by an arrow, the toner is supplied to the developing device main body 30 through the opening 31a and the toner supply port 35 while stirring.
Then, the toner is attached to the developing roller 36 that rotates clockwise by the toner supply member 37. Then, as shown in FIG. 3, the attached toner 46 is thinned at the tip of the thin layer blade 38, and the excess toner 46 is blocked by the toner blocking member 42 so as to be in front of the partition wall 32a. Let it fall. Then, the toner 46 on the surface of the developing roller 36 is attached to the photosensitive member 12 through the developing roller window 34,
The electrostatic latent image on the surface of the photoconductor 12 is visualized.

In the above-described embodiment, the damming surface 42a of the toner damming member 42 is a surface perpendicular to the lower surface of the thin blade 38. However, as shown in FIG. May be inclined. Normally, the developing roller 36
Is rotating at a high speed, and the toner 46 scraped off by the thin blade 38 strikes the toner damming member 42 at a high speed due to inertia. Therefore, by damping the damming surface 42a against which the toner 46 abuts downward, the impact of the toner 46 is softened and smoothly moved along the damming surface to be dropped. 3
8 is prevented from changing the pressure applied to the developing roller 36.

[0019]

According to the first aspect of the present invention, the toner which is scraped off from the developing roller and tries to enter the lower part along the lower surface of the thin layer blade is used as the toner dam. Since it is blocked by the stopper member, it is prevented from being scraped off by the thin blade and entering the lower side. for that reason,
The toner does not push up the thin-layer blade to fluctuate the pressure applied to the developing roller, and an image is formed on a laser printer or the like by a change in the thickness of the toner layer attached to the developing roller. The occurrence of defects can be prevented.

Further, dammed by inclined blocking plane such that the downward dammed toner toner member, since the drop from the dam to move smoothly downward along the stop surface by a thin layer blade, toner Can alleviate the impact hitting the damming surface of the toner damming member, prevent the vibration of the thin layer blade due to the shock, and further enhance the effect of preventing the fluctuation of the pressing pressure against the developing roller.

According to the second aspect of the present invention, the thin layer blade is not deformed by the deformation of the toner blocking member due to a temperature change or the like, so that the flatness of the thin layer blade is not deteriorated. The effect can be maintained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a developing device according to an embodiment of the present invention.

FIG. 2 is a front view of a toner damming member attached to the thin blade.

FIG. 3 is an operation explanatory view of a main part of the developing device.

FIG. 4 is a schematic configuration diagram showing a main part of another embodiment.

FIG. 5 is an overall schematic configuration diagram of a laser printer including such a developing device.

FIG. 6 is a schematic configuration diagram showing a part of a conventional developing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 Photoreceptor 14 Developing device 36 Developing roller 38 Thin layer blade 38a Tip 42 Toner damming member 42a Damming surface 46 Toner

Claims (2)

(57) [Claims] 1. A method according to claim 1, wherein the thin blade is rotated with respect to the rotation of the developing roller.
To the counter direction.
In a developing device of an electrophotographic apparatus which is pressed against a roller from below , a toner blocking member is provided on the lower surface of the leading end of the thin layer blade, and the blocking surface of the toner blocking member is directed downward.
A developing device for an electrophotographic apparatus, which is inclined as follows . 2. The toner damming member is flexible.
2. The developing device for an electrophotographic apparatus according to claim 1, wherein the developing device is made of a material .