JPH0478883A - Developing device for electrophotographic copying device - Google Patents

Abstract

PURPOSE:To prevent the rising of the driving torque of each roller of a developing device and the scattering of toner from a seal part even when a toner quantity is large by restoring one part of the toner fed to a developing chamber from a toner cartridge or a hopper to the cartridge or the hopper by a restoring member. CONSTITUTION:The toner T is fed to the developing chamber 30b while it is being stirred by the rotation of an agitator 34, electrostatically charged by a toner replenishing roller 36, and allowed to adhere to the surface of a developing roller 35, then the thickness of the toner layer is thinned to become a uniform thickness by a doctor roller 37. The toner is allowed to adhere to a photosensitive body 14 to visualize a latent image on the photosensitive body 14. Even when the toner cartridge 33 is full of the toner T or it is nearly full of the toner T, the toner T is restored to the cartridge 33 by the plate part 39a of the restoring member 39 which is rotating. Therefore, the toner T is not pushed in the developing chamber 30b because it is restored by the member 39 even when it is fed from the cartridge 33 by the agitator 34.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a developing device for an electrophotographic device such as a printer, a copier, or a facsimile machine. The present invention relates to a developing device for an electrophotographic apparatus, in which toner is sent into a developing chamber, and the delivered toner is attached to a photoreceptor by a developing roller to visualize a latent image on the photoreceptor.

Developing devices used in conventional electrophotographic devices use an agitator installed in the hopper or toner cartridge to agitate and send the toner into the developing chamber. The agitator always rotates at a constant speed to replenish toner into the developing chamber, regardless of the amount of toner in the hopper or toner cartridge, or the amount of toner used by the developing roller. was.

Therefore, in conventional developing devices, when the hopper or toner cartridge is full of toner, the amount of toner supplied by the agitator is very strong.

Toner is pushed into the developing chamber.

As a result, the driving torque of each roller, such as the developing roller and doctor roller in the developing chamber, increases rapidly, causing damage to the gears of the roller drive unit, strain on the drive motor, or the drive torque being reduced by the 8-force of the drive motor. There were problems such as exceeding the range. Also, the toner pressure in the developing chamber increases,
There were also problems such as toner scattering from the seal portion.

Therefore, (1) reduce the toner supply power of the agitator, (2) increase the capacity of the developing chamber so that the toner is not pushed in even if the toner is supplied from the hopper or toner cartridge. 3) It is possible to make the agitator drive independent and control the drive to adjust the toner supply amount depending on the situation at that time, but (1) is to adjust the amount of toner remaining in the hopper or toner cartridge when the toner reaches the end. (2) The developing device becomes larger, making it impossible to make the electrophotographic device more compact.
The method (3) requires a control device and the like, making the configuration complicated and causing a significant increase in cost.

Therefore, the present invention eliminates the above-mentioned problems, and even when there is a large amount of toner in the hopper or toner cartridge, the driving torque of each roller of the developing device increases, and the toner is removed from the seal portion. The purpose of the present invention is to provide a developing device that prevents the scattering of.

For this purpose, for example, as shown in the illustrated embodiment below, the invention as claimed in claim 1 is such that the toner T in the toner cartridge 33 is fed into the developing chamber 30b while being agitated by the agitator 34. The developed toner T is transferred to the developing roller 3.
In the developing unit 17 of the electrophotographic apparatus, which adheres to the photoreceptor 14 and visualizes the latent image on the photoreceptor 14 in step 5, the toner T in the development chamber sob is transferred to the toner cartridge 33.
The invention as set forth in claim 2 is characterized in that the return member 39 is rotatably provided in the developing chamber 30b. The invention according to claim 3 is characterized in that the toner in the hopper 50a is fed into the developing chamber 50b while being stirred by a seven-digitator 55, and the fed toner T is
is attached to the photoreceptor 14 by the developing roller 51 and the photoreceptor 1
In a developing device 17 of an electrophotographic apparatus that visualizes a latent image on 4, the toner T in the developing chamber 50b is transferred to the hopper 5.
The invention as set forth in claim 4 is characterized in that a return member 39 which is returned into the developing chamber 30b is rotatably provided in the developing chamber 30b. It is characterized by being provided so that it can freely reciprocate.

Part of the operation: Then, the toner T in the toner cartridge 33 or hopper 50a is sent into the developing chamber 30b or 50b while being stirred by the agitator 34 or 5S, and the delivered toner Tt is transferred to the photoreceptor 1 by the developing roller 35 or 51.
4 to visualize the latent image on the photoreceptor 14. At this time, a portion of the toner T sent into the developing chamber 30b or 50b is returned into the toner cartridge 33 or hopper 50a by the return member 39.

Sue] L-Tan Embodiments of the present invention will be described below with reference to the drawings.

FIG. 8 shows a laser printer using the developing device of the present invention. In the figure, 10 is a printer main body, and 11 is a paper feed cassette attached to this printer main body 1o. The recording paper 12 fed from the paper feed cassette 11 in the direction of the pair of registration rollers is timed by the pair of registration rollers 13 and conveyed to a latent image carrier consisting of a drum-shaped photoreceptor 14. The photoreceptor 14 is rotationally driven in a counterclockwise direction, the surface of which is charged by a charger 15, and irradiated with laser light from a laser optical system 16 to form an electrostatic latent image on the photoreceptor 14.

This latent image is made visible by toner when passing through the developing device 117 according to the present invention, and this visible image is transferred by the transfer charger 18 to the recording paper 12 conveyed to the photoreceptor 14, and the transferred record is The visible image on the paper 12 is fixed by a fixing device 19.
established by

On the other hand, residual toner is removed from the photoreceptor 14 after the visible image has been transferred by a cleaning device having a cleaning blade 21 . The toner removed from the photoreceptor 14 is collected and stored in a toner collection tank 22.

The recording paper 12 discharged from the fixing device 119 is guided to a pair of double-sided transport rollers 24 by a rotatable double-sided entrance guide 23 . The recording paper 12 is conveyed to a pair of reversing rollers 25 by a double-sided conveying roller 24 and passes through a reversing sensor 26 . After a predetermined period of time after the recording paper 12 passes the reversal sensor 25, the reversing roller pair 25 changes its rotation direction, and the rotatable reversing guide 2
7, the recording paper 12 is conveyed in the direction of the registration roller pair 13. The recording paper 12 fed to the registration roller pair 13 again is conveyed to the photoreceptor 14 at a certain timing by the registration roller pair 13, and the toner is fixed on the recording paper 12 through the same procedure as described above. At this time, since the opposite side of the recording paper 12 contacts the photoreceptor 14 than when fed from the paper cassette 11, double-sided recording is performed on the 5 recording paper 12. After the recording paper 12 on which double-sided recording has been performed passes through the manual loading device 19, it is discharged to the paper discharge section 2o by the double-sided entrance guide 23 and stored therein.

Incidentally, in the invention set forth in claim 1, the developing device 17 is configured as shown in FIG. In the figure, 30 indicates a developing device main body, and the developing device main body 30 is composed of an upper casing 31 and a lower casing 32. The developing device main body 30 is
It has a cartridge chamber 30a and a developing chamber 30b. The cartridge chamber 3a has an agitator 34 that rotates around a rotating shaft 34a, and a toner cartridge 33 containing toner T is mounted with the opening facing upward. Then, the cartridge 33 is rotated counterclockwise in FIG. 1 and set with the opening facing toward the developing chamber 30b.

The developing chamber 30b has an opening on the side facing the photoreceptor 14, and the developing roller 35 is inserted into the opening than the photoreceptor 14.
The developing roller 35 is attached in parallel with the opening, and a part of the curved surface of the developing roller 35 protrudes from the opening. Also, a toner replenishment roller 36 is in pressure contact with the developing roller 35 and attaches the toner T supplied from the toner cartridge 33 by the agitator 34 to the developing roller 35; A doctor roller 37 is provided to make the thickness uniform.

A toner sensor 38 is provided at the upper part of the developing chamber 30b, and detects that the amount of toner is low when the toner T is consumed and the detection portion is exposed.
A return member 39 for returning the toner T into the toner cartridge 23 is rotatably provided near the opening 33a of the toner cartridge 33 in the inside of the toner cartridge 23. As shown in FIG.
a, and rotating shafts 39b provided at both ends thereof. As shown in FIG. 3, the drive gear 40 of the developing roller 35 and the gear 41 of the doctor roller 37 are in mesh with each other, and the drive gear 4o and the drive gear 42 of the agitator 34 are in mesh with each other via an idler gear 43. Further, as shown in FIG. 4, another gear 44 attached to the shaft 35a of the developing roller 35 meshes with the drive gear 45 of the toner replenishing roller 36, and a gear 46 coaxial with the gear 45 and a gear 47 of the return member 39 engage with each other. are configured to mesh with each other, and as the developing roller 35 is rotated clockwise, the return member 39 is also rotated in the same direction.

The developing device 17 configured in this manner has the agitator 34, doctor roller 37,
The return member 39 rotates. Then, by the rotation of the agitator 34, the toner T is sent into the developing chamber 30b while being agitated, and the fed toner T is transferred to the toner replenishing roller 36.
is charged and adheres to the surface of the developing roller 35. The adhered toner T is thinned by a doctor roller 37 to have a uniform thickness, and is applied to the photoreceptor 14 by a developing roller 35 to visualize the latent image on the photoreceptor 14.

Then, the toner T in the toner cartridge 33 is full,
Alternatively, when the developer chamber 20b is nearly full, the amount of toner T in the developing chamber 20b increases, but the rotating plate portion 39a of the return member 39 returns the toner T into the toner cartridge 33. Therefore, even if the toner T is fed from inside the toner cartridge 33 by the agitator 35, the toner T is not pushed into the developing chamber 30b by the return of the return member 39.

Next, in the invention set forth in claim 2, the developing device 17 is configured as shown in FIG. The developing device 17 consists of the developing device 17 shown in FIG. 1, and the return member 39, as shown in FIG. 6, an elongated plate 40b whose negative end is attached to a support shaft 40a. It is mounted so as to be rotatable back and forth about the support shaft 40a, and is moved back and forth by a drive mechanism (not shown). The return member 39 may be configured to linearly reciprocate in the horizontal direction with the plate surface in the vertical direction.

Next, in the invention set forth in claim 3, the developing device 17 is constructed as shown in FIG. In the figure, 50 is a developing device main body having a developing chamber 50b and a hopper 50a.
A toner cartridge 19 is replaceably attached to an opening provided in the upper part of the toner cartridge 19 to form a sealed space. In the developing chamber 50b, a developing roller 51 is provided for attaching toner T to the electrostatic latent image formed on the photoreceptor 14 to form a visible image.
In addition, a toner replenishing roller 52 that replenishes and adheres toner T to the developing roller 51, a doctor roller 53 that makes the toner T adhered to the developing roller 51 a thin layer with a uniform thickness, and a developing roller 51. A cleaning roller 54 for cleaning is housed therein. In addition, the hopper 50a
The hopper SQa rotates around the rotation axis 55a once.
An agitator 55 is provided to feed the toner T into the developing chamber 50b while stirring it. In the developing chamber 50, there is a return member 3 that returns the toner T in the developing chamber 50b to the hopper 50a near the communication opening with the hopper 50a.
9 is rotatably provided. This return member 39
As shown at @, it is composed of a plate portion 39a and rotating shafts 39b. and.

It rotates in the same manner as the return member 39 in the invention according to claim 1.

Next, in the invention as set forth in claim 4, the developing device 17 is configured like the developing device 17 shown in FIG. The toner T in the hopper 50a is transferred to the agitator 5.
5, the toner T is sent into the developing chamber 50b while being stirred, and the delivered toner T is attached to the photoreceptor 14 by the developing roller 51, and the latent image on the photoreceptor 14 is visualized. and,
The return member 39 reciprocates to return the toner in the developing chamber 50b to the hopper 50a.

According to this invention, since the developing device of the electrophotographic apparatus is configured as described above, even when there is a large amount of toner in the hopper or toner cartridge, the return member can be easily removed. This action prevents the amount of toner in the developing chamber from becoming more than necessary. Therefore, without reducing the toner supply power, increasing the capacity of the developing chamber, or independently controlling the drive of the agitator, the increase in driving torque of each roller in the developing device can cause strain on the drive section. This prevents toner from scattering from the sealing portion due to an increase in toner pressure.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the invention according to claim 1, FIG. 2 is a perspective view of a return member thereof, and FIG. 3 is a sectional view of an embodiment of the invention. FIG. 4 is an explanatory diagram of the meshing relationship of the drive gear, FIG. 5 is a sectional view of an embodiment of the invention as claimed in claim 2, FIG. 6 is a perspective view of the return member, and FIG. 7 is as claimed in claim 2. FIG. 8 is a cross-sectional view of an embodiment of the invention described in No. 3, and FIG. 8 is a schematic explanatory diagram of a laser printer in which the invention is used.

Claims (1)

[Scope of Claims] 1. The toner in the toner cartridge is sent into the developing chamber while being agitated by an agitator, and the delivered toner is attached to a photoreceptor by a developing roller to form a latent image on the photoreceptor into a visible image. 1. A developing device for an electrophotographic device, which is equipped with a return member rotatably provided in the developing chamber for returning toner in the developing chamber into the toner cartridge. 2. An electrophotographic device in which the toner in the toner cartridge is agitated by an agitator and sent into the developing chamber, and the delivered toner is attached to a photoreceptor by a developing roller to visualize the latent image on the photoreceptor. A developing device for an electrophotographic apparatus, wherein the developing device includes a return member that returns toner in the developing chamber into the toner cartridge and is movable back and forth within the developing chamber. 3. Development in an electrophotographic device in which the toner in the hopper is sent into the developing chamber while being stirred by an agitator, and the delivered toner is attached to a photoreceptor by a developing roller to visualize the latent image on the photoreceptor. A developing device for an electrophotographic apparatus, wherein a return member for returning toner in the developing chamber into the hopper is rotatably provided in the developing chamber. 4. Development in an electrophotographic device in which the toner in the hopper is sent into the developing chamber while being stirred by an agitator, and the delivered toner is attached to a photoreceptor by a developing roller to visualize the latent image on the photoreceptor. 1. A developing device for an electrophotographic apparatus, wherein a return member for returning toner in the developing chamber into the hopper is provided in the developing chamber so as to be able to reciprocate.