JPH08220879A - Development device - Google Patents

Abstract

(57) [Abstract] [Purpose] A developing device including a guide member of a predetermined length provided on an end surface of a developing roller from an axis toward an outer peripheral direction,
Provided is a developing device which provides a developing device capable of preventing the developer from scattering and recovering the developer even if the seal member is deformed or deteriorated. [Structure] Developer carrier 9 regulated by developer regulation member 13
The developing device is provided with a collecting means 10 for developing the electrostatic latent image of the image forming body 50 with the developer 8 supplied and conveyed to the developer, and collecting the residual developer 8 on the developer carrying body 9 after the development. A seal member 17 which is in contact with a predetermined range of the lower side and the end surface of the developer carrier 9 and is fixed to the frame 16 on the lower side, the end surface of the developer carrier 9 and the shaft of the developer carrier 9. A configuration in which a first guide member 18 is formed in a gap between the side surface of the bearing 15 and the shaft 15 so as to have a predetermined length from the shaft 90 toward the outer peripheral direction, and rotates with the developer carrying member 9 when approaching or in contact with the end surface. And

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanism for collecting toner leaking from a seal of a developing roller of a developing device of a printer such as an electrophotographic printer, and more particularly to a mechanism for contacting or approaching the end surface of the developing roller in the outer peripheral direction from the shaft. The present invention relates to a developing device provided with a guide member of a predetermined length provided facing the developing device.

With the recent development of office automation, electrophotographic printing apparatuses such as laser printers are widely used in output terminals of computers, facsimile machines, copying machines and the like.

In these apparatuses, the electrostatic latent image formed on the photosensitive drum is developed with a developer by a developing roller of a developing device, and the developer remaining on the developing roller after development is collected by a collecting roller and used again for developing. However, in the vicinity of both ends of the developing roller, a predetermined area on the lower surface is sealed with a seal material to prevent the developer from leaking from the end surface in the axial direction. It deforms or deteriorates due to factors such as a gap, and the developer leaks out due to the gap in the seal part, and the developer scatters in the device and deteriorates the print quality and hygiene environment. There is a demand for a method capable of collecting the developer without scattering.

[0004]

2. Description of the Related Art FIG. 10 illustrates an internal side view of a laser printer to which the present invention is applied. In the figure, 1 is a paper feed unit accommodating and accumulating printing papers (hereinafter referred to as papers) 2,
Reference numeral 3 is a feeding roller, 4 is a conveying path, 5 is a printer section, and 6 is a stacker.

The printer section 5 includes a charging brush 51 arranged around a photosensitive drum 50a which is an image forming body, and an optical unit.
52, a developing device 7, a transfer roller 53, a static eliminator 54, a cleaner 55, and a fixing device 56.

With this structure, the surface of the photosensitive drum 50a is charged by the rotating charging brush 51 (for example, a voltage obtained by superposing an AC voltage and a DC voltage is applied), and the print information is optically modulated from the optical unit 52. The generated laser light is irradiated on the photosensitive drum 50a, and the electric charge is reduced only at the irradiated portion to form an electrostatic latent image. The electrostatic latent image on the photosensitive drum 50a is toner-developed by the developing device 7 (a bias voltage is applied to a developing roller described later).

On the other hand, the sheet 2 is unwound by the rotation of the unrolling roller 3, is conveyed in the direction of arrow A in the figure, and the sheet 2 charged from the back side by the transfer roller 53 is photosensitive drum 50.
The toner image on a is transferred, and is heated / pressurized and fixed by the fixing device 56, and the paper 2 is discharged to the stacker 6 by the discharge rollers R1 and R2.

After the transfer, the photosensitive drum is discharged by the discharging unit 54.
The toner remaining on 50a is cleaned by the cleaner 55 to prepare for the next printing operation. The developing method includes a method of using a one-component developer composed only of toner as a developer and a method of using a two-component developer in which a toner and a carrier are mixed. The toner is a powder obtained by hardening carbon and dye with wax using a resin material as a base material, and the carrier is a magnetic material, for example, a fine iron powder mainly coated with a resin material. In either case, it is the toner that is used for development. Hereinafter, the developer will be described as the toner 8a.

Next, the developing device 7 will be described in detail with reference to FIGS. 11 and 12. FIG. 11 is an internal side view of the developing device. As shown in the drawing, the developing device 7 includes a developing roller 9a and a collecting roller 10.
a, an accommodating portion 11 accommodating the toner 8a, an agitator 12 that agitates the toner 8a in the accommodating portion 11 and sends the toner 8a to the developing roller 9a, and a blade that regulates the thickness of the toner 8a supplied to the developing roller 9a. The toner cartridge 14 includes a toner cartridge 13a and a toner cartridge 14 for replenishing the storage portion 11 with the toner 8a.

12A and 12B are a plan view and a side view showing a part of the developing device 7 in a cutaway manner. As shown in the drawing, the developing roller 9a has bearings at both ends of the drive shaft 90a. 15a
The developing roller 9a is supported by the frame 16a via (15b).
A seal member 17a (17b) is provided between the lower end (a part of the outer periphery) of the end of the frame 16a and the frame 16a and between the side end surface of the developing roller 9a and the side surface of the bearing 15a (15b).

The seal member 17a (17b) is formed of, for example, urethane (or urethane home, felt), is fixed to the frame 16a, and the residual toner 8a that cannot be completely collected by the collecting roller 10a from the developing roller 9a is developed. The rollers 9a are sealed from the gap g between the both ends of the roller 9a and the bearings 15a (15b) so as not to scatter into the apparatus.

Therefore, the toner 8a regulated and supplied by the blade 13a is conveyed by the developing roller 9a and is sequentially carried to the developing position of the photosensitive drum 50a facing the developing roller 9a, and the toner 8a is used for developing. . The toner 8a remaining on the developing roller 9a after the development is collected by the collecting roller 10a.

The printer unit 5 except for the optical unit 52 and the fixing unit 56 is integrally configured as a process unit, and the life of the photosensitive drum 50a due to scratches on the surface thereof and the cleaner 55 are shown. When the waste toner tank is replaced by a new one, the process unit is replaced.

[0014]

According to the above-mentioned conventional method, the seal member prevents the toner from leaking from the end portion of the developing roller. However, before the time for replacement of the process unit comes, the seal member is removed. Deteriorates and toner leakage occurs, causing the following problems.

That is, since the seal member is in contact with the developing roller, the seal member is deformed or deteriorated due to contact pressure or frictional heat generated by rotation of the developing roller, so that a gap is created in the seal portion and toner overflows. As a result, the toner is scattered in the device and adheres to each part, which may interfere with the exposure of the optical unit or adhere to the photosensitive drum to impair the print quality, and it also takes time and effort to clean the inside of the device. Furthermore, there is a problem that the sanitary environment is deteriorated by being blown out of the apparatus as the cooling fan in the apparatus blows air.

It is an object of the present invention to provide a developing device capable of preventing the leaked developer from scattering and recovering it even if the seal member is deformed or deteriorated.

[0017]

FIG. 1 is a principle view of the present invention (Claim 1), (a) is a side view, and (b) is a main part plan view. In the figure, 8 is a developer, 15 is a bearing, 16 is a frame, 50 is an image forming body, 90 is a shaft, 9 is a developer carrier for carrying the supplied developer 8, and 13 is a developer carrier 9. A developer regulating member for regulating the supplied developer 8, 10 is a collecting means for collecting the developer 8 remaining on the developer carrier 9 after development,
Reference numeral 17 denotes a seal member that comes into contact with a predetermined range on the lower side and the end surface of the developer carrying member 9 and is fixed to the frame 16 at the lower side, and that regulates leakage of the developer 8 from the developer carrying member 18, A gap is formed between the end surface of the developer carrier 9 and the side surface of the bearing 15 of the shaft 90 of the developer carrier 9 so as to have a predetermined length from the shaft 90 toward the outer peripheral direction, and approaches or contacts the end surface to carry the developer. It is a first guide member that rotates with the body 9.

Accordingly, the electrostatic latent image formed on the image forming body 50 is developed by the developer 8 carried by the developer carrying member 9. Next, the means of claims 2 to 4 will be described.

According to a second aspect of the present invention, in the first aspect, the length of the first guide member 18 is set to a dimension such that the tip is located inside the outer periphery of the developer carrying member 9 by a predetermined dimension. A third aspect of the present invention is the developer carrier 9 according to the first or second aspect.
A second guide member is provided which is fixed to the frame 16 facing the front of each of the two ends and is in contact with the end surface of the developer carrying member 9 from the outer periphery in the direction of the axis 90 for a predetermined length.

According to a fourth aspect of the present invention, in the third aspect, an inclined surface is formed on the upper surface of the second guiding member, the inclined surface being away from the side in contact with the end surface of the developer carrying member 9 and / or lower than the tip in the fixed position direction. did.

[0021]

As shown in FIG. 1, the first guide member 18 is provided in the gap between the end surface of the developer carrier 9 and the side surface of the bearing 15 so as to approach or contact the end surface of the developer carrier 9. The developer 8 leaking from the outer periphery to the end face is solidified in the front of the first guide member 18 in the rotational direction, gradually grows in the tip direction, and can be guided from the upper end of the seal member 17 on the end face to the outside. Therefore, even if the developer carrying member 9 is used for a long period of time and the seal member 17 is deformed or deteriorated, the developer 8 can be prevented from leaking and scattering from the seal member 17, and the developer 8 can be recovered. it can.

Next, the operation of claims 2 to 4 will be described. In the second aspect, the length of the first guide member 18 is set to a dimension such that the tip is located inside the outer periphery of the developer carrying member 9 by a predetermined dimension, so that the first guide member 18 moves forward in the moving direction. The amount of the developer 8 that solidifies is limited and does not overflow, so that the effect of claim 1 can be further enhanced.

According to the third aspect of the present invention, the second guide member is provided on the frame 16 facing the front of both ends of the developer carrying member 9, so that the developer 8 solidified in the front direction of rotation of the first guide member 18 is fixed. The first guide member 18 can be guided to the second guide member from the tip end portion thereof to be collected, and the first guide member 18 can be collected.
The effect of can be further enhanced.

According to the present invention, since the inclined surface is formed on the upper surface of the second guiding member, the guided developer 8 can be collected by dropping on the inclined surface. Can be increased.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments 1 and 2 in which the present invention is applied to a developing device of a laser printer described in the conventional example will be described below with reference to FIGS.
This will be described with reference to FIG. The same reference numerals denote the same objects throughout the drawings.

1) Embodiment 1 Embodiment 1 (corresponding to claim 1 and embodiment 2) will be described with reference to FIGS. 2 is a configuration diagram showing a first embodiment of the present invention, FIG. 3 is a configuration diagram showing a paddle of the first embodiment, FIG.
FIG. 5 is a diagram for explaining the operation of the first embodiment, and FIG. 5 is a diagram showing the experimental results of the first embodiment.

Toner 8a, developing roller 9a and blade shown in FIG.
13a, bearings 15a and 15b, paddle 18a and photosensitive drum
The reference numeral 50a corresponds to the developer 8, the developer carrier 9, the developer regulating member 13, the bearing 15, the first guiding member 18, and the image forming body 50 in FIG.

As shown in the plan view of FIG. 2A and the side view of FIG. 2B, in the developing device 7a, a paddle 18a is provided in a gap between both end surfaces of the developing roller 9a and a side surface of the bearing 15a (15b). , (1
8b) is provided.

The paddle 18a (18b) is in contact with the end surface of the developing roller 9a and has a width of about ½ of the gap (for example, when the gap is 2 mm, the width of the paddle 18a (18b) is set to about 1 mm).
Thus, the developing roller 9a is formed into a shape curved in a convex shape with respect to the rotation direction, the length is set so that the tip position is inside the outer periphery of the developing roller 9a by a predetermined dimension, and the tip is the seal member 17a ( It does not come in contact with 17b). (For example, the diameter of the developing roller 9a: φ20 mm, the diameter of the shaft 90a:
In the case of φ8 mm, the position of the tip of the paddle 18a (18b) is set to 2 mm inside the outer circumference of the developing roller 9a. ) Also, as shown in FIGS. 3 (a) and 3 (b), the paddles 18a (18b) are ring-shaped.
It is integrally formed with 180, and the ring 180 is attached to the shaft 90 as shown in FIG.
It is press-fitted and attached to a.

Having such a structure, the operation will be described with reference to FIG. In this case, it is assumed that the developing roller 9a has been used for a long period of time and the deformation or deterioration of the seal member 17a (17b) has already progressed, and the toner 8a has leaked from the seal portion.

As shown in FIG. 4, the developing roller 9a is used during development.
When the paddle 18a (18b) rotates along with the rotation of the paddle 18a (18b), the toner 8a leaking from the seal portion of the seal member 17a (17b) at the end of the developing roller 9a moves forward in the rotation direction of the paddle 18a (18b). It becomes a lump and grows in the circumferential direction of the developing roller 9a.

The lump of the grown toner 8a is a seal member 17
It is possible to extend the duration of the effect of preventing the scattering of the leaked toner 8a by hitting the upper end of a (17b) and flowing to the outside, dropping and collecting. By extending the duration of this effect, the developing roller 9a
It is possible to prevent the toner 8a from leaking from the seal members 17a and 17b.

In this case, an experiment was conducted by changing the length and width of the paddle 18a (18b), and the effect duration was measured. The results are shown in FIG. Here, the diameter of the developing roller 9a: φ20 mm, the diameter of the drive shaft 90a of the developing roller 9a: φ8 mm, the gap between the ends of the developing roller 9a: 2 mm, the contact width between the seal member 17a (17b) and the developing roller 9a: 3 mm.

As shown in FIGS. 5A and 5B, when the length of the paddle 18a (18b) exceeds the outer peripheral position of the developing roller 9a, the effect duration is halved, and the width of the paddle 18a (18b) is reduced. It can be seen that the duration of the effect is halved if it exceeds 1/2 of the gap at the end of the roller 9a.

2) Embodiment 2 Embodiment 2 (claim 1, claim 2, claim 3 and claim 4)
6) to FIG. 9 will be described. 6 is a configuration diagram showing a second embodiment of the present invention, FIG. 7 is a configuration diagram of a toner receiver of the second embodiment, FIG. 8 is an operation explanatory diagram of the second embodiment, and FIG. 9 is a diagram showing an experimental result of the second embodiment. Is.

The toner receiver 19a (19b) of FIG. 6 corresponds to the second guiding means of claim 3. As shown in FIGS. 6 (a) and 6 (b), both ends of the developing roller 9a are moved forward (the photosensitive drum 50).
The toner receiver 19a (19b) is fixed to the frame 16a (a side). The tip of the toner receiver 19a (19b) is set to a length that is a little distance from the tip of the paddle 18a (18b) on both end surfaces of the developing roller 9a. Further, as shown in FIGS. 7 (a) and 7 (b), an inclined surface 20 (angles α and β in the figure) is provided on the upper surface of the toner receiver 19a (19b) so as to move away from the end surface of the developing roller 9a and the outer peripheral direction of the end surface. ) Has been formed. Therefore, it goes without saying that the inclined surfaces 21 of the toner receiver 19a and the toner receiver 19b are formed in opposite directions.

Having such a structure, the operation will be described with reference to FIG. Also in this case, the seal member 17a (17b)
The state of is assumed to be the same as the case of the first embodiment.
As shown in FIG. 8, when the developing roller 9a rotates in the direction of the arrow and the paddle 18a (18b) rotates during development, the developing roller 9a rotates.
The toner 8a leaking from the seal portion of the seal member 17a (17b) at the end of 9a is solidified in the front direction of rotation of the paddle 18a (18b) and grows in the circumferential direction of the developing roller 9a.

The lump of the grown toner 8a is the paddle 18a (18
From the tip of b), the toner is moved by being guided to the tip of the toner receiver 19a (19b), flows down along the inclined surface 20 and is collected. It can be extended further than the case.

In this case, the experiment was conducted by changing the presence or absence of the toner receiver 19a (19b) and the inclination angles (α and β) of the toner receiver 19a (19b), and the result of measuring the duration of the effect is shown in FIG. Shows. In this case, the main dimensions of the developing roller 9a are the same as those in the first embodiment.

From FIG. 9 (a), it is understood that even if the toner receivers 19a (19b) are provided and the inclined surface 20 is not formed, a remarkable effect is obtained. Further, from (b), it was confirmed that the effect can be further enhanced by forming the inclined surface 20 on the upper surface of the toner receiver 19a (19b) in the downstream direction in which the toner 8a flows.

[0041]

As described above, according to the present invention,
According to the first aspect of the present invention, even if the seal member is deformed or deteriorated by using the developer carrier for a long period of time, the developer does not leak from the seal member and scatter and the developer can be recovered continuously. Since the time can be extended, it is possible to prevent the inside of the apparatus from being blown out and the blowing out to the outside of the apparatus until the time when the process unit is to be replaced, and it is possible to save the labor of cleaning and prevent the print quality and the sanitary environment from being impaired.

In the second aspect, the amount of the developer that is solidified in the forward direction of the movement of the first guiding member is limited and does not overflow, so that the effect of the first aspect can be further enhanced. According to a third aspect of the present invention, the developer solidified in the front of the moving direction of the first guiding member can be guided from the tip end portion of the first guiding member to the second guiding member and collected. The effect of 2 can be further enhanced.

In the fourth aspect, the induced developer falls on the inclined surface, and the effect of the third aspect can be further enhanced. There is an effect.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a configuration diagram showing a first embodiment of the present invention.

FIG. 3 is a configuration diagram showing a paddle of the first embodiment.

FIG. 4 is an operation explanatory diagram of the first embodiment.

FIG. 5 is a diagram showing experimental results of Example 1.

FIG. 6 is a configuration diagram showing a second embodiment of the present invention.

FIG. 7 is a configuration diagram of a toner receiver according to a second exemplary embodiment.

FIG. 8 is an operation explanatory view of the second embodiment.

FIG. 9 is a diagram showing experimental results of Example 2.

FIG. 10 is an internal side view of a laser printer to which the present invention is applied.

FIG. 11 is a side view of the inside of a conventional developing device.

FIG. 12 is a configuration diagram of a conventional developing roller.

[Explanation of symbols]

7, 7a is a developing device, 8 is a developer, 8a
Is toner, 9 is a developer carrier, 9a and 9b are developing rollers, 10 is a collecting means, 10a is a collecting roller, 13 is a developer regulating member, 13a is a blade, 15 is a bearing,
15a and 15b are bearings, 16 and 16a are frames, 17 and 17a and 17b are sealing members, 18 is a first guiding member,
18a is a paddle, 19a and 19b are toner receivers, 20 is an inclined surface, 50 is an image forming body, and 50a is a photosensitive drum.

Claims (4)

[Claims] 1. A developer carrying member for carrying the supplied developer, a developer regulating member for regulating the developer supplied to the developer carrying member, and a developer carried by the developer carrying member. A developing device comprising: a recovery unit that recovers the developer remaining on the developer carrier after the electrostatic latent image formed on the image forming body is developed, A sealing member that contacts a predetermined range of the side and the end face and is fixed to the frame on the lower side to regulate the leakage of the developer from the developer carrier, and the end face of the developer carrier and the shaft of the developer carrier. A first guide member which is formed in a gap from the side surface of the bearing toward the outer peripheral direction from the shaft and has a predetermined length, and which rotates with the developer carrier when approaching or in contact with the end face. Development device. 2. The developing device according to claim 1, wherein the length of the first guiding member is set to a dimension such that the tip is located inside the outer periphery of the developer carrier by a predetermined dimension. 3. A second guide member fixed to frames facing the front of both ends of the developer carrying member, and contacting the end surface of the developer carrying member with a predetermined length from the outer circumference in the axial direction. 3. The developing device according to claim 1 or 2. 4. An inclined surface is formed on the upper surface of the second guide member, the inclined surface being distant from a side in contact with the end surface of the developer carrying member and / or lowering from a tip in a fixed position direction. 3 developing device.