JPH08328382A - Electrophotographic developing device - Google Patents

Abstract

PURPOSE: To prevent toner from being leaked from an electrophotographic device. CONSTITUTION: This device is provided with a case 60 for containing the toner. A developing roller 61 is rotatably supported in the case. The developing roller is provided with an abrasion resistance coating film 61c formed on both end periphery of the roller part 61b of the developing roller 61. A sealing material 81 is interposed between the case 60 and the abrasion resistance coating film 61c of the developing roller 61 formed on the both end periphery of the roller part 61b. Since the abrasion resistance coating film 61c is formed on the roller part 61b contacting with the sealing material 81, damage of the roller part 61, and the leakage of the toner are prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic developing device used in, for example, a facsimile device, a page printer device and a copying machine.

[0002]

2. Description of the Related Art Conventionally, an electrophotographic recording type printing apparatus has been used in, for example, a facsimile apparatus, a page printer apparatus and a copying machine. The printing apparatus has a developing unit and a fixing unit, and the developing unit is provided with a drum unit, an electrophotographic developing unit, and the like. Then, in the developing section, the outer peripheral surface of the photosensitive drum of the drum unit is electrified and charged, an electrostatic latent image of a recording pattern is formed on the outer peripheral surface of the photosensitive drum, and the electrostatic latent image of the photosensitive drum is fixed by the electrophotographic developing unit. Toner is attached to the electrostatic latent image, the toner attached to the photosensitive drum is transferred to the recording paper, and then the toner transferred to the recording paper is heated and fixed in the fixing unit.

Further, the electrophotographic developing unit has a case, a toner storage portion for storing toner is formed in the case, and a developing roller is pivotally supported facing the toner storage portion. Then, by rotating the developing roller, in the toner storage portion, to which the toner is attached, against the photosensitive drum, the toner is attached to the electrostatic latent image on the photosensitive drum.

The developing roller is provided with a roller portion made of conductive rubber, and shaft portions protruding from both ends of the roller portion are rotatably supported by the case. Further, a seal material made of, for example, a felt material is interposed between the both end peripheral surfaces of the roller portion of the developing roller and the case. The pressure of the seal material and the elasticity of the roller portion cause the roller portion and the case to be separated from each other. The gap is closed to prevent toner from leaking out of the case.

[0005]

However, in order to improve the image quality of the printed matter, a toner having a smaller particle diameter or a more rounded particle is used, and therefore the toner is a roller of the developing roller. Easily gets into the contact surface between the seal and the seal. The toner that has entered between the roller part and the seal material is agglomerated by frictional heat, and if the friction between this agglomeration soul and the rotating roller part continues for a long period of time, damage such as cracks will occur on the surface of the rubber roller part. However, there is a problem in that it causes toner leakage.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electrophotographic developing apparatus capable of reliably preventing toner leakage.

[0007]

An electrophotographic developing apparatus of the present invention has a case for accommodating toner, a roller portion and a shaft portion protruding from both ends of the roller portion and rotatably supported by the case. A developing roller having abrasion resistant coatings formed on both circumferential surfaces of the roller portion, and the case and the circumferential surface of both ends of the roller portion having the abrasion resistant coating formed on the developing roller. And a sealing material.

[0008]

In the electrophotographic developing apparatus of the present invention, since the abrasion resistant coating is formed on the peripheral surfaces of both ends of the roller portion of the developing roller that comes into contact with the seal material, toner is not formed between the roller portion and the seal material. Even if it gets in and agglomerates and friction between the agglomerate soul and the rotating roller portion occurs, damage to the roller portion is prevented. Since the abrasion resistant coating generally has a small frictional resistance, the developing roller can be smoothly rotated.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of an embodiment of the electrophotographic developing apparatus of the present invention will be described below with reference to the drawings.

In FIG. 5, 11 is a device body of the facsimile machine, and the device body 11 has a body 12 forming an outer shell. An operation panel 14 is provided on the upper surface of the body 12, and an inclined document table 15 for setting a transmission document is located at the rear side of the operation panel 14.
Is provided. A receiver (not shown) is placed on one side of the body 12.

In addition, the body 12 is provided with a document insertion portion 16 having an opening on the upper surface thereof, which is continuous with the document table 15, and a document discharge port 18 which is opened on the front surface. A document passage 19 that conveys a transmission document is formed from the document insertion portion 16 to the document discharge port 18. Then, along the document path 19, a transmission unit for reading the transmission document.
20, a pull-in roller 21 that separates and pulls in the originals one by one, a plurality of sets of conveying rollers 22 that conveys the originals in the original passage 19, a reading unit 24 that reads the transmitted originals, and the reading unit 24. A white roller 25 and the like for pressing the document is arranged.

Further, a cassette insertion portion 31 is formed on the bottom of the body 12, and a rectangular frame-shaped sheet feeding cassette 33 is inserted and removed from an insertion opening 32 provided on the front surface of the cassette insertion portion 31. It has become so. And this paper cassette
A push-up plate 35 whose rear side is biased upward by a spring body 34 is swingably provided on the 33, and a plurality of recording papers P are stacked and stored on the push-up plate 35. There is. A paper holder 36 is provided at the rear end of the paper feed cassette 33, and the claw portions 36a formed by bending the paper holder 36 lock both sides of the rear end of the recording paper P. It is like this.

A recording paper feed-out port 37 is provided at the rear of the cassette insertion portion 31 of the body 12, and a recording paper discharge port 38 is formed at the front of the body 12. A recording paper passage 39 is formed from the recording paper feed-out port 37 to the recording paper discharge port 38 so as to make a U-turn.

Further, the cassette insertion portion 31 of the body 12 is provided with a feeding roller 41 located in front of the recording paper feeding port 37, and the recording paper on the push-up plate 35 biased upward. P is pressed against the feeding roller 41. Then, by rotating the feeding roller 41, the claw portion of the paper feeding cassette 33
The recording papers P locked by 36a are separated one by one and fed out to the recording paper feed-out port 37.

Along the recording paper path 39, there are arranged a draw-in roller 43 for drawing in the recording paper P fed out into the recording paper path 39, a developing section 44, a fixing section 45 and the like. The developing unit 44 includes an electrophotographic photosensitive drum unit 47 and an electrophotographic developing unit as an electrophotographic developing device.
It is composed of 48 and an optical system unit 49.

In the developing section 44, an electric charge is applied to the outer peripheral surface of the photosensitive drum 51 of the electrophotographic photosensitive drum unit 47, and a laser beam emitted from the optical system unit 49 causes the outer peripheral surface of the photosensitive drum 51 to have a recording pattern. An electrostatic latent image is formed and toner is supplied from the electrophotographic developing unit 48,
It is attached onto the electrostatic latent image on the photosensitive drum 51. Further, the transfer device 52 transfers the toner image attached to the photosensitive drum 51 onto the recording paper P being conveyed. In the fixing unit 45, the recording paper P coated with toner is passed between the heated rollers 54, 54 to fix the toner onto the recording paper P.

Further, as shown in FIGS. 1 to 4, the electrophotographic developing unit 48 is detachably attached to the unit main body 55 and the unit main body 55.
A toner cartridge 56 that supplies toner to 55 is provided. Note that this toner has a fine particle diameter of about 10 μm in order to improve image quality.

The unit body 55 has a case 60 made of, for example, synthetic resin. This case 60
Is a box shape whose longitudinal direction is the width direction of the device body 11,
A developing roller 61 that supplies toner to the photosensitive drum 51, a supply roller 62 that supplies toner to the developing roller 61, and an agitator 63 that stirs the toner are attached to the case 60.

Further, the case 60 is formed with a pair of end plate portions 66, 66 on both sides. Then, these end plate portions 66,
The front side of the step 66 is expanded in a stepwise manner through the step portions 67, 67, and the partition wall portion 68 flush with the step portion 67 and the rear side portion between the end plate portions 66, 66 are closed from the bottom portion. And a rear plate portion 69 which is connected to each other. A toner storage portion 71 that stores toner is formed by being surrounded by the end plate portions 66, 66, the partition wall portion 68, and the rear plate portion 69. Further, an upper side of the toner storage portion 71 is opened and a toner cartridge connecting portion 72 for connecting the toner cartridge 56 is formed. Further, the lower part of the partition 68 is opened and a toner supply port 74 is formed. The front plate portions 75, 75 are connected to the front end portions of the end plate portions 66, 66, respectively.
Mounting portions 75 for supporting the electrophotographic developing units 48, respectively.
a and 75a are connected.

Then, the toner accommodating portion 71 has a stirring blade 63a.
The agitator 63 provided with is disposed, and by rotating the agitator 63, the toner in the toner storage portion 71 is agitated and the fixation of the toner is prevented. A toner supply port is provided near the bottom of the toner storage unit 71.
The supply roller 62 is arranged to face 74.

A developing roller 61 is arranged in front of the toner supply port 74, that is, in front of the step 67 of the end plate 66. Then, the developing roller 61
Has a shaft portion 61a and a roller portion 61b formed around the shaft portion 61a and made of conductive rubber, and a rear side portion of the roller portion 61b is provided with a supply roller 62 via a toner supply port 74.
The front side of the roller portion 61b protrudes toward the front side of the case 60, and the protruding portion is pressed against the photosensitive drum 51 of the electrophotographic photosensitive drum unit 47.

Then, these developing roller 61 and supply roller
62, and the rotary shafts 61a, 62a, 63b of the agitator 63,
The end plates 66 on both sides are fitted to each other, rotatably supported by the end plates 66, and rotationally driven in predetermined directions (arrow R directions in the drawing) by gear trains not shown.

Further, the case 60 is provided with a developing blade 76 which is located above the developing roller 61, that is, at a position which is displaced by about 90 degrees from the pressure contact portion with the supply roller 62 in the rotational direction. . The developing blade 76 is pressed against the outer peripheral surface of the roller portion 61b of the developing roller 61 by a spring (not shown) and forms a thin layer of toner having a uniform thickness on the outer peripheral surface of the roller portion 61b. It is like this.

In this way, as the rollers 61 and 62 and the agitator 63 rotate, the toner is carried in the toner storage portion 71 in a predetermined direction (direction of arrow F in the figure), and the supply roller is supplied.
Toner is supplied from 62 to the developing roller 61, and the developing blade is
The toner layer formed on the roller portion 61b of the developing roller 61 by the 76 is attached to the electrostatic latent image on the photosensitive drum 51. The bottom portion of the rear plate portion 69 of the case 60 is formed in an arc shape along the shapes of the rollers 61 and 62 and the rotation locus of the stirring blade 63a of the agitator 63, so that the toner flows efficiently. .

A recovery sheet 77 is provided below the developing roller 61, and the recovery sheet 77 is brought into pressure contact with the lower surface of the developing roller 61, whereby the developing roller
Toner is prevented from leaking from the lower side of 61.

Further, the roller portion 61b of the developing roller 61 is formed so that its longitudinal dimension is larger than that of the supply roller 62 and the toner supply port 74, and both end portions deviated from the printing area are stepped portions.
67, 67 are arranged so as to project to the front side of 67. on the other hand,
Under the stepped portions 67, 67, arcuate portions 67a, 67a are formed along the shape of the roller portion 61b of the developing roller 61.

Then, the arcuate portion 67a of these stepped portions 67, 67.
, 67a are fitted with sealing materials 81, 81, respectively, to seal the gap between the stepped portions 67, 67 and the roller portion 61b of the developing roller 61, and the case 60 and the roller portion 61b of the developing roller 61. The flow of the toner that tries to enter the gap between and is blocked.

The sealing material 81 is formed, for example, by coating a felt material, which is a fiber, with grease, which is an oil, and impregnating it. The felt material is made of, for example, polytetrafluoroethylene (trade name: Teflon) fiber which is generally used in the past. Also,
Grease is usually used as a lubricant, and uses oil and fat in a semi-solid state at room temperature.

Abrasion resistant coating 61c is formed on the peripheral surfaces of both ends of the roller portion 61b of the developing roller 61. The abrasion-resistant coating 61c is formed by coating, for example, polytetrafluoroethylene (trade name: Teflon), and its formation area is the contact area with the seal material 81 and outside the printing area.

According to this embodiment, the particle size is 1
When the toner of about 0 μm is used, since the sealing material 81 in which the felt material is impregnated with semi-solid grease which is a collection of particles of 10 μm or less is used, the gap between the fibers of the felt material is filled and the sealing material 81 In addition to increasing the density, the stickiness of the grease enhances the adhesion between the seal material 81 and the roller portion 61b of the developing roller 61 and the case 60 to prevent passage of the toner having a particle diameter of about 10 μm and prevent the toner from leaking. Can be reliably prevented.

Further, even if the toner enters between the roller portion 61b of the developing roller 61 and the seal material 81 and the toner is agglomerated by frictional heat to cause friction between the agglomeration soul and the rotating roller portion, Since the abrasion-resistant coating 61c is formed on the both end surfaces of the roller portion 61b that comes into contact with the seal material 81, it is possible to prevent damage such as cracks on the roller portion 61b, and reliably prevent toner leakage. be able to.

Further, the seal material 81 is impregnated with grease which is a lubricating oil and fat, and the roller portion 61b of the developing roller 61 has an abrasion resistant coating 61c which generally has a small frictional resistance.
By forming the, the rotation of the developing roller 61 can be made smooth.

Further, since the abrasion resistant coating 61c of the roller portion 61b of the developing roller 61 can be formed by coating the material of the abrasion resistant coating 61c on the roller portion 61b, the manufacturing cost can be reduced. .

[0034]

According to the electrophotographic developing apparatus of the present invention, since abrasion-resistant coatings are formed on the peripheral surfaces of both ends of the roller portion of the developing roller that comes into contact with the sealing material, the roller portion and the sealing material are not separated from each other. Even if the toner gets in between and agglomerates to cause friction between the agglomerate soul and the rotating roller portion, damage to the roller portion can be prevented, and toner leakage can be reliably prevented. Since the abrasion resistant coating generally has a small frictional resistance, the developing roller can be smoothly rotated.

[Brief description of drawings]

FIG. 1 is a sectional view taken along line AA of FIG. 2 showing an embodiment of an electrophotographic developing device of the present invention.

FIG. 2 is a sectional view taken along line BB of FIG. 1 of the electrophotographic developing apparatus of the above embodiment.
It is sectional drawing.

FIG. 3 is a partial enlarged cross-sectional view of the electrophotographic developing apparatus according to the above embodiment, which corresponds to FIG.

FIG. 4 is an enlarged cross-sectional view of a part of the electrophotographic developing apparatus of the above embodiment corresponding to FIG.

FIG. 5 is a sectional view of a facsimile machine using the electrophotographic developing apparatus of the above embodiment.

[Explanation of symbols]

 60 Case 61 Developing roller 61a Shaft part 61b Roller part 61c Abrasion resistant film 81 Seal material

Claims (1)

[Claims] 1. A case for accommodating toner, a roller portion and a shaft portion projecting from both ends of the roller portion and rotatably supported by the case, wherein abrasion resistance is provided on both peripheral surfaces of the roller portion. It is characterized by comprising: a developing roller having a coating formed thereon; and a seal material interposed between the case and both end circumferential surfaces of the roller portion of the developing roller having the abrasion resistant coating formed thereon. Electrophotographic developing device.