JPH11316500A - Image recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a toner from leaking from a developing roller part of a developing device unit in an image recorder, using an electrophotographic system. SOLUTION: For this image recorder, the boundary part of a side sealing member 47 preventing a toner 40 from leaking from the end part of a developing roller 43, a bottom sealing member 58 brought into press-contact with the bottom part of the roller 43 through a film member 59 and a bracket 63 to which the member 59 is attached, the end part of the member 47 is brought into press- contact with the end part of the member 58, also a protruding part 47c brought into press-contact with the end part of the bracket 63 is formed on the member 47, and the members 47 and 58 are constituted of a closed-cell foam sponge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus using an electrophotographic system, and more particularly to an image recording apparatus configured to prevent toner from leaking from a developing roller portion of a developing unit.

[0002]

2. Description of the Related Art Conventionally, in an image recording apparatus using an electrophotographic system, toner is stored in a developing unit constituting a process unit, and the toner is transferred from a supply roller of the developing unit to a developing roller. The toner is transferred to the photosensitive drum of the drum unit via the developing roller. In this case, the toner is carried out from the inside of the developing unit to the outside through the developing roller within a range in which the toner is transferred to the photosensitive drum. As described above, in the range where toner is transferred to the photosensitive drum, it is necessary to carry out the toner from the developing unit to the outside. Is leaked to the outside of the process unit. Therefore, it is important to prevent leakage of the toner by performing sealing outside the range where the toner needs to be carried out. So, for example,
A seal member for preventing leakage of toner from both ends of the developing roller is provided. A film member is provided below the developing roller so as to guide the toner not transferred to the photoreceptor roller so as to be collected in the developing device unit. A seal member is provided to prevent leakage from below the seal member to the outside.

[0003]

However, in the above-described image recording apparatus, the boundary between the seal member for preventing toner leakage at both ends of the developing roller and the seal member for preventing toner leakage from below the developing roller. In some cases, a slight gap may occur due to the assembling accuracy of these seal members, and there is a risk that toner may leak out of this gap. It is also important to seal the supply roller so as to prevent the toner from entering the support portion for transferring the toner to the developing roller, and to keep the supply roller and the like in a good rotation state.

[0004]

The present invention uses the following means to solve the above-mentioned problems in the image recording apparatus. That is, an image recording apparatus for transferring toner stored in a developing device unit to a photosensitive drum via a developing roller according to claim 1, wherein the elasticity prevents toner leakage from an end of the developing roller. A side seal member, an elastic bottom seal member pressed against the bottom of the developing roller via a film member, and a bracket to which the film member is attached, wherein the elastic side seal member, the elastic bottom seal member, At the boundary of the three members with the bracket, the end of the elastic side seal member and the end of the elastic bottom seal member are brought into pressure contact with each other, and the elastic side seal member is formed with a convex portion that comes into pressure contact with the end of the bracket.

According to a second aspect of the present invention, there is provided an image recording apparatus for transferring toner stored in a developing unit to a photosensitive drum via a developing roller, comprising a supply roller for transferring the toner to the developing roller. At both ends, a ring-shaped supply roller seal member having an inner diameter smaller than the outer diameter of the supply roller shaft of the supply roller is fitted.

According to a third aspect of the present invention, the elastic side seal member and the elastic bottom seal member of the image recording apparatus according to the first aspect, or the supply roller seal member of the image recording apparatus according to the second aspect is a single-cell sponge. It consists of.

[0007]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a side sectional view showing the inside of the image recording apparatus of the present invention, FIG. 2 is a side sectional view showing a developing unit and a drum unit, and FIG. 3 is an elastic side seal member for a developing roller and a toner film thickness regulating blade. FIG. 4 is a cross-sectional view taken along line XX in FIG. 3, FIG. 5 is a plan cross-sectional view showing an elastic side seal member disposed at an end of the developing roller, and FIG. FIG. 7 is a plan sectional view showing a boundary portion between the seal member and the bracket, and FIG. 7 is a plan sectional view showing a sealed state at an end of the supply roller.

The schematic configuration of the image recording apparatus of the present invention will be described with reference to FIGS. This image recording apparatus
For example, the present invention is applied to an electrophotographic image recording apparatus in a facsimile or the like. A process unit 9 is disposed above an image recording apparatus 8, and the process unit 9 includes a drum unit 10, a developing unit 4, and the like. I have. A photosensitive drum 1 is disposed in the drum unit 10, and a charger 2, an optical writing unit (LED head array) 3, and a developing device are provided around the photosensitive drum 1 along the rotation direction (arrow A). The unit 4, the transfer unit 5, the memory removing member 51, and the insulating member 52 are arranged in this order.

The photosensitive drum 1, the charger 2, the memory removing member 51 and the insulating member 52 are unitized as a drum unit 10, and the photosensitive drum 1 of the drum unit 10
Drum shaft 1a is detachably engaged with the developing unit 4. The process unit 9 is detachably mounted on the main body frame 21. When the process unit 9 is mounted on the main body frame 21, the developing unit 4 is rotatably supported by the main body frame 21 and the drum unit 10 The drum shaft 1 a is supported by a U-shaped groove formed in the main body frame 21. Then, the drum unit 10 and the developing unit 4 are integrated, and the drum unit 1
0 can be removed above the main body frame 21,
When a paper jam occurs in the process unit 9, the paper can be easily taken out.

A fixing unit 6 for fixing the toner image transferred to the sheet is disposed downstream of the drum unit 10. The fixing unit 6 includes a heating roller 61 and a pressure roller 62 pressed against each other. It is configured. On the upstream side of the drum unit 10, sheet transport rollers 71 and 72 are provided.
A recording paper supply / conveyance system 7 including a 72 ′, pickup rollers 73/73 ′, and paper feed cassettes 74/74 ′ is provided. The charger 2 is a brush roller type charger in which a roller surface is covered with a conductive fiber brush, and a bias voltage is applied to the charger 2 to uniformly rotate the peripheral surface of the photosensitive drum 1 while rotating. It is charged to approximately -750V. The transfer unit 5 is made of a conductive foam made of urethane resin or the like, and a constant current bias voltage (for example, 500 V to 2 kV) is applied to the transfer unit 5.

The developing unit 4 is provided between a developing device main body 41 for storing the toner 40, a supply roller 42 disposed below the developing device main body 41, and the supply roller 42 and the photosensitive drum 1. A developing roller 43 positioned so as to be in contact with each other, a stirring member 44 disposed in the developing device main body 41 to stir the stored toner 40,
And a toner thickness regulating blade 45 resiliently provided on the downstream peripheral surface of the third toner 40 in the transport direction.

The developing roller 43 is formed of a rubber member or the like.
Developing roller shaft 43a made of metal such as stainless steel
2, the developing roller 43 is applied with a bias voltage of, for example, about -300 V. Further, the toner film thickness regulating blade 45 is provided with the toner 40 adhered to the outer peripheral surface of the developing roller 43.
The blade is a blade that regulates the film thickness, and is made of an elastic stainless member or the like. A bias voltage of, for example, about -650 V is applied to the toner thickness regulating blade 45. The supply roller 42 is made of urethane foam or the like, and rotates in the direction of arrow C in FIG. 2 around a supply roller shaft 42a formed of metal such as stainless steel. Bias voltage is applied.

The center distance between the supply roller 42 and the developing roller 43 is set to be slightly smaller than the sum of the respective roller radii when the supply roller 42 and the developing roller 43 are driven. As a result, the contact portions of the two rollers are brought into a pressure contact relationship. The frictional action between the roller 42 and the developing roller 43 due to the pressure contact relationship and the rotation directions of the arrows B and C, and the bias voltage applied to each roller 42 The existing toner 40 is charged. Then, by the rotation of the supply roller 42 in the direction of arrow C, the toner 40 filled in the bubbles of the supply roller 42 is transferred to the developing roller 43 side, and at the pressure contact portion between the supply roller 42 and the developing roller 43, both rollers are used. Due to the potential difference between 42 and 43, the toner 40 adheres to the surface of the developing roller 43. The developing roller 43 is in pressure contact with the photosensitive drum 1, and the toner 40 attached to the surface of the developing roller 43 is conveyed toward the photosensitive drum 1 by the rotation of the developing roller 43 in the direction of arrow B. On the way, for example, the layer thickness of the toner 40 attached to the surface of the developing roller 43 becomes uniform by the toner film thickness regulating blade 45 applied to about -650 V.

Next, an image forming process in the image recording apparatus configured as described above will be briefly described. The photoreceptor drum 1 rotates in the direction of arrow A, and the outer peripheral surface of the photoreceptor drum 1 is uniformly charged to approximately -750 V by the charger 2 composed of a conductive fiber brush. Thereafter, the light writing unit 3 irradiates the surface of the photosensitive drum 1 with light based on the image information. Photoconductor drum 1
Is made of a grounded photoconductor, the potential of the portion irradiated with light, that is, the portion of the image information corresponding to black is -30 V
And a potential difference occurs between the light-irradiated portion (the portion corresponding to the black of the image information) and the non-irradiated portion (the portion corresponding to the white of the image information). An electrostatic latent image corresponding to the image information is formed on the side surface.

This electrostatic latent image reaches the developing unit 4 and
The electrostatic latent image adheres to the outer peripheral surface of the developing roller 43 and is substantially
When the toner 40 charged to 650 V comes into contact with the photosensitive drum 1 due to a potential difference from a light irradiation site.
The photosensitive drum 1 is sucked and moved to the light irradiation portion on the surface,
A toner image is formed on the surface. The toner image reaches a contact portion between the photosensitive drum 1 and the transfer device 5 by rotation of the photosensitive drum 1, and the contact portion is provided with the pickup roller in synchronization with the rotation of the photosensitive drum 1. The recording paper fed out one by one from a paper feed cassette 74 (74 ') by 73 is introduced through transport rollers 72 (72') and 71. Since a bias voltage of 500 V to 2 kV is applied to the transfer device 5, the toner image on the surface of the photosensitive drum 1 is sucked by the transfer device 5 and adheres to the recording paper and is transferred. The recording paper onto which the toner image has been transferred is the photosensitive drum 1
Further, the sheet is further conveyed by the rotation of the transfer unit 5 and reaches the fixing unit 6.

The recording paper that has reached the fixing unit 6 is introduced into a pressure contact portion between the heating roller 61 and the pressure roller 62.
Here, the resin component contained in the toner 40 is
The recording sheet is melted by the heating / pressing action of 1.62 and fused to the sheet to form a permanent image, and the recording sheet is discharged out of the apparatus. After the transfer of the toner image onto the recording paper, the surface of the photosensitive drum 1 has a voltage of about 0 V due to the operation of the transfer device 5, and a small amount of untransferred toner remains. The photoreceptor drum 1 continues to rotate thereafter, the surface thereof is uniformly charged by the charger 2 as described above, and the subsequent process is repeated.

On the other hand, untransferred toner remaining on the surface of the photosensitive drum 1 is removed from a memory removing member 51 provided separately from the charger 2.
When the voltage is applied to the photosensitive drum 1, it is disturbed by the action of the memory removing member 51 and is dispersed and charged on the surface of the photosensitive drum 1. In this case, the memory removing member 51
Since the insulating member 52 is interposed between the charging device 2 and the charging device 2, even if the two devices approach each other, there is no problem in image formation. Since the toner remaining on the surface of the photosensitive drum 1 is dispersed, it does not affect light irradiation by the optical writing unit 3 and does not hinder image formation. The dispersed residual toner reaches the developing unit 4, and the unnecessary toner is sucked by the potential difference with the developing roller 43 and is collected in the developing unit main body 41.

Next, a sealing structure for preventing toner leakage from the developing unit 4 will be described. The developing device unit 4 has an opening on the surface on the photosensitive drum 1 side. A developing roller 43 and a toner film thickness regulating blade 45 and the like are disposed in the opening, and adhere to the outer peripheral surface of the developing roller 43 with a constant film thickness. The discharged toner 40 is transferred to the photosensitive drum 1. 3 and 4, the toner thickness regulating blade 45 attached to the developing device main body 41 is elastically provided on the outer peripheral surface of the developing roller 43 on the downstream side in the transport direction of the toner 40, as described above. .

At both ends of the developing roller 43, elastic side seal members 47 each made of an elastic member such as a single-cell sponge are provided, and the elastic side seal members 47 are integrally formed with the developing roller seal portion. 47a and a blade seal portion 47b. The developing roller seal 47a closes the gap between the axial end 4a of the opening in the developing unit 4 and the end of the developing roller 43, and the blade seal 47b causes the axial end 4a and the toner film to close. The gap with the end of the thickness regulating blade 45 is closed so that the toner 40 does not leak from the inside of the developing unit 4. That is, the elastic side seal member 47 applies the toner 40 from the end of the developing roller 43.
This is a seal member for preventing leakage and leakage of the toner 40 from the end of the toner thickness regulating blade 45.

The developing roller seal portion 47a is provided on the photosensitive drum 1 on the developing device main body bottom surface 41a of the developing device main body 41.
From the side end, the developing roller 43 in the inner direction of the developing unit 4
It is disposed upward along the outer peripheral surface, and its upper end reaches near the leading end 45 a of the toner film thickness regulating blade 45. The blade seal portion 47b extends upward from the upper end of the developing roller seal portion 47a.
Further, an auxiliary seal member 49 made of an elastic member such as a single-cell sponge is provided on the developing roller seal portion 47a of the elastic side seal member 47 in a direction inside the developing unit 4. The auxiliary seal member 49 includes the developing roller seal portion 4.
7a is pressed toward the outside of the developing unit 4, whereby the outer peripheral surface of the developing roller 43 and the developing roller seal portion 47a are brought into close contact with each other, and a sealing property for preventing toner leakage from the end of the developing roller 43 is provided. Is increasing.

Further, as shown in FIG.
An elastic bottom seal member 58 made of an elastic member such as a single cell sponge is provided on the lower developing device main body bottom surface 41a, and the elastic bottom seal member 58 is pressed against the bottom of the developing roller 43 via a film member 59. ing. The film member 5
9 is attached to a bracket 63 arranged at the end of the developing device main body bottom surface 41a on the side of the photosensitive drum 1, and the bracket 63 is formed of, for example, a sheet metal member. The elastic bottom seal member 58 prevents the toner 40 on the outer peripheral surface of the developing roller 43 collected in the developing unit 4 without being transferred to the photosensitive roller 1 from leaking from below the developing roller 43 to the outside. To the ceiling.

As shown in FIG. 5, a portion of the developing roller seal portion 47a of the elastic side seal member 47 located at the end of the developing device main body bottom surface 41a on the photosensitive drum 1 side projects inward in the axial direction. The projection 47c is formed. As shown in FIG. 6, the tip of the projection 47c is in pressure contact with the axial end of the bracket 63, and the end of the elastic bottom seal member 58 located closer to the supply roller 42 than the bracket 63. The end of the elastic side seal member 47 is in pressure contact.

As described above, the elastic bottom seal member 58 and the elastic side seal member 47 are pressed against each other, so that the sealing performance between the elastic bottom seal member 58 and the elastic side seal member 47 is improved. The toner 40 is prevented from leaking to this portion, and furthermore, by forming a convex portion 47c on the elastic side seal member 47 and pressing it against the bracket 63, the sealing property between the convex portion 47c and the bracket 63 is improved. This prevents leakage of the toner 40 in this portion. That is, at the end of the developing roller 43, the sealing between the developing roller 43 and the developing device main body bottom surface 41 a by pressure contact between the elastic bottom seal member 58 and the elastic side seal member 47, and the convex portion 47 c and the bracket 63 The seal is double-sealed by the pressure contact to improve the sealing property, and the leakage of the toner 40 is surely prevented.

Further, since the convex portion 47c of the elastic side seal member 47 is pressed against the end of the bracket 63, even if the mounting position of the elastic side seal member 47 to the developing device main body 41 is slightly shifted, the convex portion 47c is convex. Since the sealing performance between the portion 47c and the bracket 63 can be maintained, the mounting accuracy of the elastic side seal member 47 does not need to be made very high, and the mounting performance of the elastic side seal member 47 can be improved. .

As shown in FIG. 7, the supply roller shaft 42a of the supply roller 42 is rotatably supported by the developing device main body 41 at both ends via bearings 65. On the inner side in the axial direction of the bearing 65, a bearing seal member 66 made of an elastic member such as a single-cell sponge is fitted in close contact with the supply roller shaft 42a, and the toner 40 does not enter the bearing 65. So that it is sealed. Further, at both ends of the supply roller 42, a supply roller seal member 67 made of an elastic member such as a single-cell sponge and formed in a ring shape is fitted on the supply roller shaft 42a. The supply roller seal member 67 has an inner diameter smaller than the outer diameter of the supply roller shaft 42a, is attached in close contact with the supply roller shaft 42a, and has a side end face of the supply roller 42 and a developing device. It is in pressure contact with the wall surface of the container body 41.

The supply roller 42 is sealed from the end of the supply roller 42 into a gap 68 formed between the supply roller shaft 42a and the developing device main body 41 so that the toner 40 does not enter. Thus, the sealing property of the part is improved, and the rotation state of the supply roller 42 is kept good. Although the supply roller seal member 67 has an inner diameter smaller than the outer diameter of the supply roller shaft 42a, the supply roller seal member 67 is formed in a ring shape and an elastic member such as a single-cell sponge. And the supply roller seal member 6
The workability when assembling 7 to the supply roller shaft 42a is good. Since the bearing seal member 66 also has elasticity, the workability at the time of assembling to the supply roller shaft 42a is good.

[0027]

According to the present invention, the following effects can be obtained by employing the above-described configuration in the image recording apparatus.
An image recording apparatus for transferring toner stored in a developing device unit to a photosensitive drum via a developing roller according to claim 1, wherein the elasticity is such that toner leakage from an end of the developing roller is prevented. A side seal member, an elastic bottom seal member pressed against the bottom of the developing roller via a film member, and a bracket to which the film member is attached, wherein the elastic side seal member, the elastic bottom seal member, At the boundary between the three members with the bracket, the end of the elastic side seal member and the end of the elastic bottom seal member are brought into pressure contact with each other, and the elastic side seal member is formed with a convex portion that comes into pressure contact with the end of the bracket. The gap between the developing roller and the bottom surface of the developing device main body at the end of the developing roller is formed by pressure contact between the elastic bottom seal member and the elastic side seal member. Ring, and, by sealing doubly sealing by pressure contact between the convex portion and the bracket of the elastic side seal member can be improved sealing properties, it was possible to prevent leakage of reliably toner. The pressure contact between the end of the elastic side seal member and the end of the elastic bottom seal member, and the press contact between the protrusion of the elastic side seal member and the end of the bracket are performed by the end of the elastic side seal member and the end of the elastic bottom. Since the seal member has elasticity, the elastic side seal member can be easily pressed into contact with the developing device main body even if the assembly position thereof is slightly shifted, thereby maintaining the sealing property between the convex portion and the bracket. Therefore, it is not necessary to make the assembling accuracy of the elastic side seal member so high, and the assembling property of the elastic side seal member can be improved.

Further, a ring-shaped supply roller seal member having an inner diameter smaller than the outer diameter of the supply roller shaft of the supply roller is provided at both ends of the supply roller for transferring the toner to the developing roller. Because of the fitting, the toner can be sealed from the end of the supply roller so as to prevent toner from entering the gap formed between the supply roller shaft and the developing device main body, thereby supporting the supply roller. Thus, the sealing property of the portion where the roller was placed was improved, and the rotation state of the supply roller could be kept good. Further, since the supply roller seal member is formed in a ring shape, workability when assembling the supply roller seal member to the supply roller shaft can be improved.

Further, as in the third aspect, the elastic side seal member and the elastic bottom seal member of the image recording apparatus according to the first aspect, or the supply roller seal member of the image recording apparatus according to the second aspect, may be a single element. Since it is composed of a foam sponge, the single foam sponge has elasticity, so that the sealing member can be easily pressed into contact with the sealing member without requiring the assembling accuracy, and the elastic side seal member and the elastic bottom seal are provided. It is possible to improve the workability when assembling the member to the developing device main body and when assembling the supply roller seal member to the supply roller shaft, and it is possible to easily obtain a high sealing property, thereby reliably preventing toner leakage. Could be prevented.
In addition, the material was inexpensive, and the protrusion of the elastic side seal member could be easily processed, so that the cost could be reduced.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing the inside of an image recording apparatus of the present invention.

FIG. 2 is a side sectional view showing a developing unit and a drum unit.

FIG. 3 is a front view showing a seal portion of a portion of a developing roller and a toner film thickness regulating blade formed by an elastic side seal member.

FIG. 4 is a sectional view taken along line XX in FIG. 3;

FIG. 5 is a plan sectional view showing an elastic side seal member arranged at an end of a developing roller.

FIG. 6 is a plan sectional view showing a boundary portion between the elastic side seal member, the elastic bottom seal member, and the bracket.

FIG. 7 is a cross-sectional plan view showing a sealing state at an end of a supply roller.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photosensitive drum 4 developing unit 8 image recording device 9 process unit 10 drum unit 40 toner 42 supply roller 42a supply roller shaft 43 developing roller 47 elastic side seal member 47a developing roller seal portion 47c convex portion 58 elastic bottom seal member 59 film member 63 Bracket 67 Supply roller seal member

Claims (3)

[Claims] 1. An image recording apparatus for transferring toner stored in a developing unit to a photosensitive drum via a developing roller, wherein the elastic side seal member prevents toner from leaking from an end of the developing roller. And an elastic bottom seal member pressed against the bottom of the developing roller via a film member;
In a configuration provided with a bracket to which the film member is attached, an end of the elastic side seal member and an elastic bottom seal member are formed at a boundary between the elastic side seal member, the elastic bottom seal member, and the bracket. An image recording apparatus, wherein an end portion is brought into pressure contact with the elastic side seal member, and a projection is formed on the elastic side seal member to come into pressure contact with the bracket end portion. 2. An image recording apparatus for transferring toner stored in a developing unit to a photosensitive drum via a developing roller, wherein the toner is supplied to both ends of a supply roller for transferring the toner to the developing roller. An image recording apparatus, wherein a ring-shaped supply roller seal member having an inner diameter smaller than an outer diameter of a supply roller shaft of a roller is fitted. 3. The elastic side seal member and the elastic bottom seal member of the image recording apparatus according to claim 1, or 2.
3. The supply roller seal member of the image recording apparatus according to claim 1, wherein the supply roller seal member is constituted by a single-cell sponge.
The image recording apparatus according to claim 1.