JPH03204667A - Developing device for electrophotogrpahic device - Google Patents

Abstract

PURPOSE:To prevent contamination inside a device main body caused by the scattering of toner and the degradation of image quality by providing a rotary body adjoining to the end face of a developing roller, rotating in the opposite direction of its rotational direction, and faster than its rotational speed. CONSTITUTION:When the driving gear 51 of the developing roller 41 rotates in the direction of A, the developing roller 41 rotates in the direction of B as well. On the other hand, when the driving gear 53 of a toner replenishing roller 40 rotates in the direction of D via an idler gear 52 rotating in the direction of C, the toner replenishing roller 40 rotates in the direction of E. A transmission gear 47 integrated to the toner replenishing roller 40 rotates in the direction of F, and the rotary body 46 meshing with the transmission gear 47 rotates in the direction of G which is the opposite direction of the rotational direction of the developing roller 41 rotating in the direction of B, and faster than the rotational speed of the developing roller 46. Therefore, the toner between the rotary body 46 and the developing roller 41 returns to a developing room 37. Thus, contamination inside a device main body caused by the scattering of toner and the degradation of image quality are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention can be applied to electrophotographic devices that record on paper using an electrophotographic process, such as printers, copiers, and facsimile machines that use lasers. More specifically, the present invention relates to a developing device that visualizes a latent image on a photoreceptor using toner in such an electrophotographic apparatus.

Conventionally, in this type of developing device, for example, as shown in FIG. The toner replenishing roller 5 and the layer thinning member 6 are arranged around the developing roller 3 while being pressed against it through the sheet 4 and supported by the support member 2, and are pressed parallel to the developing roller 3.

Then, the toner is frictionally charged by the toner replenishing roller 5 and adheres to the developing roller 1, and after the toner is uniformly thinned by the thinning member 6, the developing roller 3 is moved as shown in FIG. Then, the latent image on the photoreceptor 8 was made visible using toner.

Problems to be Solved by the Invention However, in the conventional configuration, when the toner 7 is made into a thin layer as shown in FIG. The toner 7b that has entered between the sealing member 1 and the sealing member 1 is carried along the end surface of the developing roller 3 in the rotational direction of the developing roller 3, and as shown in FIG. There was a problem with the water erupting. Further, there is a problem in that the spouted toner 7G scatters outside the developing device and contaminates the inside of the apparatus main body, leading to a deterioration in image quality.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to prevent, in a developing device of such an electrophotographic apparatus, toner scraped off by a layer thinning member to be carried along the end surface of the developing roller in the direction of rotation and scattered outside the developing device. The purpose is to prevent toner from staining the inside of the device and deteriorating image quality.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention presses a toner replenishing roller and a layer thinning member against a developing roller in parallel with the axial direction thereof, and presses the developing roller against a photoreceptor. In a developing device of an electrophotographic apparatus that visualizes a latent image on a photoreceptor with toner, the developing roller rotates along the axial end surface of the developing roller in a direction opposite to the rotating direction of the developing roller. It is characterized by being provided with a rotating body that rotates faster than the rotational speed.

Due to the rotation of the 5-rotator, the toner between the rotor and the developing roller is spilled in the opposite direction to the rotating direction of the developing roller.
Return to developing room.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 4 is a laser printer equipped with a developing device according to the present invention, and shows the overall schematic structure of its internal mechanism.

In the figure, what is indicated by the reference numeral 1o is the main body of the apparatus. On the outside of the device main body 10, there is a paper feed tray 1 on the right side in the figure.
1 is removably loaded, and paper 12 which is a recording medium is loaded therein.
to store. The device main body 10 also has an outer case 1.
3 includes a drum-shaped photoreceptor 14, a charger 15, an optical writing device 16, a developing device 17 according to the present invention, a transfer device 18, a cleaning device 19, a fixing device 20, and the like. Then, as the photoreceptor 14 rotates, the charger 1 charges the surface of the photoreceptor 14.
5, the optical writer 16 electronically converts the video signal sent from the outside, scans the exposure using a laser beam to form an electrostatic latent image, and transfers this electrostatic latent image to a developer. In step 17, the toner image is visualized.

On the other hand, the paper 12 in the paper feed tray 11 is transferred to the paper feed roller 21.
and send it out to the photoreceptor 14 by the registration rollers 22. Then, the toner image is transferred onto the paper 12 by the transfer device 18, and the paper 12 is separated from the photoreceptor 14 by a separating section (not shown) and conveyed to the fixing device 20. Then, in the fixing device 20, the hot roller 23 and the pressure roller 24 are
After fixing by applying heat and pressure, the paper ejection roller 25
26, the paper is selectively delivered to and stacked on a paper discharge tray 27 or 28.

On the other hand, the photoreceptor 14 after the visible image transfer is transferred to the cleaning device 1.
Remove the residual toner with the cleaning blade 29 of 9,
Thereafter, static electricity is further removed using a static electricity removal brush (not shown). The toner removed from the photoreceptor 14 is collected by a collection roller 30.
is sent into the collection tank 31 and collected there.

By the way, in the laser printer mentioned above.

The developing device 17 is constructed by attaching a toner cartridge 36 on a developing case 35 as shown in FIG.
The toner 38 is replenished into the developing chamber 37 inside. The developing chamber 3
7 includes an agitator 39 and a toner supply roller 40. A developing roller 41, a blade-like layer thinning member 42, and the like are accommodated, and the developing device 17 is urged by an unillustrated urging means to press the developing roller 41 against the photoreceptor 14. Then, the agitator 39 is rotated about the support shaft 39a in the direction indicated by the arrow to supply the toner 38 to the toner replenishing roller 40 side while agitating it. The toner replenishing roller 40 also bites into the developing roller 41 rotating in the counterclockwise direction shown by the arrow with a certain biting amount while rotating in the counterclockwise direction shown by the arrow, and the toner 38 is frictionally charged and the developing roller 41 electrostatically. Then, by the rotation of the developing roller 41, the developing roller 41 carries and feeds the developing roller,
A thinning member 42 uniformly thins the toner 38. At the same time, the toner 38 is more strongly tribo-electrified by the cutting friction between the thinning member 42 and the developing roller 41. Then, the toner 38 is electrostatically transferred to the surface of the photoreceptor 14 by the developing roller 41,
The electrostatic latent image on the surface of the photoreceptor 14 is visualized.

Now, in the developing device 17 according to the present invention, as shown in FIG. 1, the lubricant sheet 45 and the rotating body 46 are sequentially fitted onto the roller shafts 41a, 4, 1a of the developing roller 41. The rotating body 46 is made of a hard elastic member such as foamed polyurethane, and is formed in the shape of a gear.
41a so that it can rotate freely, and meshes with the transmission gear 47.

The transmission gear 47 is fixed to the roller shafts 40a, 40a of the toner replenishment roller 40, and the toner replenishment roller 40
Provided integrally with Roller shaft 41 of the developing roller 41
a.41a is rotatably supported by the annular portion 48a of the support member 48. Further, the roller shafts 40a, 40a of the toner replenishing roller 4o are rotatably supported by a bracket portion 48b that is integrated with the annular portion 48a. The support member 48
is provided with a vertical groove portion 48c integrally with the annular portion 48a.

Both ends of the thinning member 42 are fitted into the vertical groove portion 48c and supported. Further, a flocking brush 50 is attached and attached to the bracket portion 48b, and the tip of the brush is brought into contact with the outer periphery of the rotating body 14. Long roller shafts 41 of each of the developing roller 41 and the toner supply roller 40
a.40a penetrates the support member 48 and protrudes outward. A driving gear 51 is fixed to the long roller shaft 41a of the developing roller 41. The driving gear 51 meshes with a gear train (not shown) that transmits driving force from a driving source, and also connects to the toner replenishing roller 4 via an idler gear 52.
It meshes with the drive gear 53 which is fixed at zero. Then, the gear ratio from the drive gear 51 of the developing roller 41 to the rotating body 46 via the idler gear 52 and the like is set to 0.5 to 0.
8, and the rotational speed of the rotating body 46 is set to 1.2 to 2 times the rotational speed of the developing roller 41.

Therefore, due to the driving force from the driving source, the developing roller 41
When the drive gear 51 rotates in the direction of arrow A, the developing roller 41 also rotates in the direction of arrow B.

On the other hand, the drive gear 53 of the toner supply roller 40 rotates in the direction indicated by the arrow C via the idler gear 52 which rotates in the direction indicated by the arrow C. Then, the toner replenishment roller 40 rotates in the direction of arrow E, and the transmission gear 47 integrated with the toner replenishment roller 40 rotates.
rotates in the direction of arrow F. As shown in FIG. 2, the rotating body 46 meshing with the transmission gear 47 rotates in the direction of arrow G, which is the opposite direction to the rotation direction of the developing roller 41, which rotates in the direction of arrow B, and the rotating body 46 engages with the transmission gear 47. Rotates faster than the rotation speed. The rotating body 46 that rotates faster than the developing roller 41 causes the rotating body 46 and the developing roller 4 to
The toner that has entered between the developing roller 1 and the developing roller 41 is returned to the developing chamber 37 by overcoming the developing roller 41.

Also, the toner 38 that has entered the tooth groove 46a of the rotating body 46
is scraped off with the flocking brush 50 and transported into the developing chamber 37 by the centrifugal force of the rotating body 46.

In the above-described embodiment, the rotating body 46 is rotated via the transmission gear 47 that is integrated with the toner replenishing roller 40, but in this invention, the rotating body 46 is a gear that transmits the driving force from the drive source. It may also be configured to rotate by directly engaging with the row.

Effects of the Invention According to the present invention, the rotation of the rotating body causes the toner between the rotating body and the developing roller to be scattered in the opposite direction to the rotating direction of the developing roller and returned to the developing chamber, so that the toner is removed from the developing roller. This eliminates the possibility of spraying out and scattering outside the developing device on the downstream side in the rotational direction of the roller. Therefore, it is possible to prevent the inside of the apparatus body from becoming dirty or from deteriorating image quality due to toner scattering.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of a portion of the developing device of the present invention, FIG. 2 is an explanatory diagram illustrating the operation of a portion of the developing device, FIG. 3 is a schematic configuration diagram of the developing device, and FIG. 4 1 is a schematic diagram of the entire internal mechanism of a laser printer including the developing device. Fig. 5 is an illustration of how toner scatters from between the developing roller and the toner seal member in a conventional developing device, and Fig. 6 is an illustration of how toner is carried in the rotational direction of the developing roller in a conventional developing device. 7 are partially exploded perspective views of a conventional developing device. 14...Rotating body 17...Developer 38...Toner 4o...Toner supply roller 41...
Developing roller 42 Thinning member 46 Rotating body

Claims (1)

[Claims] An electrophotographic device in which a toner supply roller and a layer thinning member are pressed against a developing roller in parallel with the axial direction of the developing roller, the developing roller is pressed against a photoreceptor, and the latent image on the photoreceptor is visualized with toner. An electrophotographic apparatus, wherein the developing device is provided with a rotating body adjacent to an axial end surface of the developing roller, rotating in a direction opposite to the rotational direction of the developing roller, and rotating faster than the rotational speed of the developing roller. Developing device.