JPH1048949A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device which can prevent the scattering of a toner from the end of a developing roller, without hurting the assembly property and the decomposing property of a developing roller unit. SOLUTION: This device has a photoreceptor drum 1; a developing roller 5 provided opposing to the photoreceptor drum 1 in a specific developing area on the peripheral surface of the photoconductor drum 1; and a lower case main body to support the photoreceptor drum 1 and the developing roller 5; while the developing roller 6 is supported by support members 35a and 35b to support the both ends of the developing roller 5 in the shaft longitudinal direction. Urethane form of seal members 531 and 541 are provided along the opposing surfaces of the supporting members 35a, and 35b, and the case main body 2a, with the photoreceptor drum 1, and opposing surfaces of the support members 35a and 35b with the case main body 2a, respectively, and the developing area is made in a closely sealing condition by holding the seal members 531 and 541 by the three members of the photoreceptor drum 1, the case main body 2a, and the support members 35a and 35b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic image forming apparatus such as a copying machine, a facsimile, and a printer.

[0002]

2. Description of the Related Art A photosensitive drum, a developing roller arranged opposite to the photosensitive drum in a predetermined developing area on the peripheral surface of the photosensitive drum, and a case for supporting the photosensitive drum and the developing roller Having a main body, the developing roller is supported by a support member that supports both ends in the axial longitudinal direction,
2. Description of the Related Art An image forming apparatus configured to be attached to a case body is known. In such an image forming apparatus, the peripheral surface of the photosensitive drum at the axial end of the developing roller in the developing region where the developing roller and the photosensitive drum are opposed to each other and the supporting member of the developing roller. The seal against the toner scattering from the gap between them is incomplete, and the toner scattering cannot be prevented. As a means to prevent toner scattering,
The following attempts have been made:

Conventional Example 1 FIG. 10 is a cross-sectional view of an image forming apparatus viewed from an axial direction of a photosensitive drum.
Are arranged facing each other. The developing roller 5 is supported at both ends in the axial direction by support members 35a (35b), and is attached to the lower case 2a which is a part of the main body case. The shafts 34a and 34b of the developing roller are supported by a main body side plate (not shown). A doctor blade 35 is provided between the support members 35a and 35b in a bridge shape. Further, an entrance seal 311 for preventing toner scattering is provided using the support members 35a and 35b such that the leading end thereof is close to the peripheral surface of the photosensitive drum 1. In such a configuration, a portion denoted by reference numeral 371 corresponding to an extension of the developing area in the axial direction of the developing roller is a support member 35.
A gap is formed between the photosensitive drum 1 and the photosensitive drum 1. The toner scatters outside from the gap 371.

Conventional Example 2 As shown by reference numeral 312 in FIG. 11, a urethane foam-like elastic sealing member 312 is provided along the supporting members 35a and 35b so as to fill the gap 371 in FIG. By doing so, the portion of the gap 371 is filled with the seal member 312, so that the toner is not scattered from the portion, but the seal member 312 is
a, 35b, the lower casing 2a
A gap as shown by reference numeral 472 remains between
The toner scatters from the gap 472.

Conventional example 3 Therefore, as shown in FIG. 12, if the seal member 312 is extended downward and provided so as to span the end of the lower casing 2a so as to fill the gap 472 in FIG. Although there is no room, the lower portion of the seal member 312 is sandwiched between the lower casing 2a and the photosensitive drum 1, so that the seal member 312 is integrally formed with the support members 35a and 35b. In addition, there is a problem that it is difficult to perform the attaching / detaching operation of the developing roller unit to / from the case body.

[0006]

In each of the above examples,
As described above, if the seal is to be completed, the assembling property and the disassembling property are sacrificed, which is not preferable for a copier or the like that requires a lot of maintenance at the user's site. Furthermore, assuming recycling, which is rapidly spreading in the future, it is important that the developing roller unit can be easily disassembled, and the disassembly and assemblability cannot be neglected.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of preventing toner from being scattered from an end of a developing roller shaft without impairing the assembling property and disassembly of the developing roller unit.

[0008]

The present invention has the following configuration to achieve the above object. (1) A photoreceptor drum, a developing roller arranged opposite to the photoreceptor drum in a predetermined developing area on a peripheral surface of the photoreceptor drum, and a case body for supporting the photoreceptor drum and the developing roller Wherein the developing roller is detachably attached to the case body as a developing roller unit supported by a supporting member that supports both ends in the axial longitudinal direction thereof. A urethane foam-type seal member is provided over each of the facing surfaces of the case main body facing the photoconductor drum and the support members and the facing surfaces of the case main body. The developing region is sealed by being sandwiched between the case body and the support member (claim 1).

(2) In the image forming apparatus according to (1), a sheet member having a smaller coefficient of friction than the seal member is interposed between the seal member and the photosensitive drum.

(3) In the image forming apparatus described in (2), the sheet member is a part of a part of an entrance seal provided for preventing toner scattering.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

Example 1 This example corresponds to the example of the invention described in claim 1. In FIG. 1, a urethane foam-shaped seal member 531 is provided over the facing surface between the support member 35a and the photosensitive drum 1 and the facing surface between the support member 35a and the lower casing 2a. Similarly, a urethane foam-shaped seal member 541 is provided over the facing surface between the lower casing 2a and the photosensitive drum 1 and the facing surface between the lower casing 2a and the support member 35a. Further, in the assembled state, the seal member 531 and the seal member 541 are brought into close contact with each other at a portion indicated by reference numeral B where the three members of the photosensitive drum 1, the support member 35a, and the lower casing 2a are closest to each other. The sealing member 531 is composed of the three members of the support member 35a and the lower casing 2a.
And the seal member 541 is sandwiched. The periphery of the support member 35b on the opposite side is also configured according to the support member 35a.

In this manner, the two seals 531 and 541 are deformed in accordance with the gap on the surface facing the photosensitive drum 1 to fill the gap, thereby preventing toner scattering. In addition, since the two seals 531 and 541 can be vertically separated from each other at the opposing contact portion, the developing roller unit can be easily pulled out and disassembled, and conversely, when assembling, The two seals 531 and 541 can be kept in close contact only by placing the developing roller unit on the lower casing 2a. Therefore, the seal in the axial direction of the developing roller is completed, and the developing roller unit can be easily assembled and disassembled.

In the above example, the support members 35a, 35b,
The developing roller 5, the doctor blade 35, and the like are configured as an integral cartridge, and are configured to be easily detachable from the image forming apparatus. By simply mounting the cartridge on the image forming apparatus, the end of the cartridge Are completely sealed and the sides are sealed. Therefore, it is possible to easily prevent the toner from scattering from the side, and to prevent the inside of the image forming apparatus and the user environment from being soiled by the toe, and to prevent the toner from scattering to other units and images.

Example 2 This example corresponds to the example of the second aspect of the present invention. This will be described with reference to FIG. In this example, the basic sealing structure is the same as that described with reference to FIG. A characteristic point of the present embodiment is that, as shown in FIG.
1 and the photosensitive drum 1, these seal members 53
Sheet member 691 having a smaller coefficient of friction than 1, 541
a, 691b. Alternatively, as shown in FIG. 2B, a sheet member 691ab is provided such that the sheet member 691a and the sheet member 691b in FIG. 2A are constituted by one sheet, and only the contact portion with the seal member 531 is bonded. It may be fixed with a material. Therefore, the photosensitive drum 1 comes into contact with the seal members 531 and 541 via the sheet member 691a, the sheet member 691, or the sheet member 691ab. FIG.
In the example shown in FIG. 2A, the sheet member 691a and the sheet member 691b are not integrated, or when integrated as shown in FIG. 2B, the sheet member 691b is bonded only to the seal member 531 to form a seal. Since it is not bonded to the member 541, there is no inconvenience in disassembling. Note that, in this example, the sheet member 691 is
1 and 541 are provided, but may be provided on either one of them.

In this manner, when the photosensitive drum 1 rotates, the sheet member 691 comes into contact with the photosensitive drum 1, so that the friction between the photosensitive member 1 and the seal members 531, 541 is lower than when the seal members 531, 541 directly contact the photosensitive drum 1. In addition to reducing the resistance and reducing the torque burden, it is possible to prevent or delay the loss of the seal members 531 and 541 due to the sliding contact with the photosensitive drum 1 and the wear of the photosensitive layer on the photosensitive drum surface. The rotation and surface state of the body drum can be maintained in a stable and favorable state.

Example 3 This example corresponds to the example of the third aspect of the present invention. In this example, as the sheet member 691ab described with reference to FIG. 2B, a part of an entrance seal provided for preventing toner scattering is extended and used. Many entrance seals extend the end of the entrance seal in order to prevent the carrier from dropping at the shaft end of the developing roller. The entrance seal is provided in sliding contact with the photosensitive drum for the purpose of preventing toner from scattering from the developing area. Therefore, the entrance seal has a small coefficient of friction and does not wear the photosensitive drum. Therefore, the material of the conventionally used entrance seal is not changed, the dimensions are changed, and it is extended to a portion corresponding to the sheet member 691ab in FIG. 2B, and the sheet member 691ab is extended with the extended portion of the entrance seal. It can fulfill the role of.

FIG. 3 shows an example in which the end 33c of the seal 33, which is an extension of the entrance seal, extends from the support member 35a to the seal members 531 and 541.
FIG. 4 shows the whole of the seal 33, and the end 33c is shown.
Is the portion that extends the longest downward, and the inside of this end 33c is gradually reduced, and the side seals 33b,
Each of the entrance seals 33a is formed. As shown in FIG. 4, ideally, the end 33c completely covers the seal members 531 and 541. However, the end 33c partially covers, for example, only the rubbing area between the seal member 531 and the photosensitive drum 1. Or end the end 33c there,
Alternatively, the effect can be obtained even if the end 33c is configured to extend to the developing roller side along the mating surface of the seal members 531 and 541 through the rubbing area between the seal member 531 and the photosensitive drum 1. it can.

Example 4 An example of the mutual dimensional relationship between the photosensitive drum 1, the developing roller 5, and the seal 33 will be described with reference to FIG. In FIG. 5, the width W2 (= 302 mm) of the entrance seal 33a is the charging width W.
1 (= 299 mm). Entrance seal 33a
There is a region of the side seal 33b outside each of them, and further, there is an end 33c outside the side seal 33b.
The width B1 of the side seal 33b is 10 mm and the end 3
The width B2 of 3c is 5 mm. The developing sleeve 5a covers at least the side seal 33b, and the longitudinal end of the magnet group MG in the developing sleeve is
3b. The width W3 of the magnet group MG is 306 mm, and the size and positional relationship such that the end of the magnet group MG is located at a position 2 mm inside the side seal 33a from the entrance seal 33a toward the side seal 33b. Becomes The width W4 of the photosensitive drum 1 is larger than the entire width of the seal 33.

Here, the function of the side seal 33b will be described. In FIG. 6, in a region other than the end portion of the developing sleeve 5a corresponding to the magnet group MG, a so-called spike by the carrier is formed at a certain height H1, but the magnet group MG is formed.
In the longitudinal end, that is, in the region that does not contribute to development, the thickness of the layer to which the carrier is attached becomes thin,
It has attenuated to the height H2 of the ear. On the other hand, the toner separated from the carrier scatters around due to the rotation of the developing sleeve 5a. Then, the side seal 3b is located at the position of the carrier ear height H2 at the end of the magnet group MG. In this case, the side seal 3b covers the seal portion formed by the carrier, so that toner leakage from both sides of the developing sleeve 5a can be prevented.

Example 5 Application Example of the Present Invention to an Image Forming Apparatus In FIG. 7A, a member having a substantially U-shaped cross section and a long member in the longitudinal direction of the developing roller 5 is formed by a side member. This is the adhered member 30 of the seal 33. Both ends in the longitudinal direction of the adhered member 30 are closed by side members 30a (in FIG. 7A, the back side member is not shown).
The middle portion in the longitudinal direction sandwiched between the side members 30a has a substantially U-shape, but more specifically, a slope is provided such that the distance between the opposing plates increases toward the opening side.

One of the U-shaped portions is a seal mounting plate 30b, and the plate facing the seal mounting plate 30b is a facing plate 30b.
Called c. One end of a seal 33 made of a synthetic resin thin plate is adhesively fixed to the seal mounting plate 30b.
On the other hand, a pre-doctor 32 is formed on the facing plate 30c. 7A, a fitting projection 30b-1 having a small thickness is formed in the vicinity of the side member 30a of the seal mounting plate 30b, as shown in an enlarged manner in FIG. 7B. I have. As shown in FIG. 7A, a hook 30 d protrudes from one end of the adhered member 30.

On the other hand, as shown in FIG. 7A, the developing sleeve 5a constituting the developing roller 5 has one end in the longitudinal direction of the shaft integrally formed with a shaft 34b.
b is supported by the support member 35b. Developing sleeve 5
The other end of a is supported by a shaft 34a fixed to the support member 35a. The magnet group MG is fixed to the shaft 34a. As a result, the developing sleeve 5a is
Can be rotated around the magnet group MG. In FIG. 7A, the support member 35a is formed with a concave portion 35-1 that can be fitted with the fitting convex portion 30b-1.

Attachment portions 35a-1 and 35b-1 protrude integrally with the support members 35a and 35b. Then, the doctor blade 35 is attached to the mounting portion 35a-
1, 35b-1, and is attached by a screw 36. The shape and size of the doctor blade 35 in the thickness direction when the doctor blade 35 is superimposed on these mounting portions 35a-1 and 35b-1 are drafted so as to match the U-shape of the adhered member 30. It is formed. Also, the support member 3
5a and 35b are dimensioned so as to fit inside the side members 30a and 30a.

Therefore, as shown in FIG. 7A, the attachment members 30 separated from each other are attached to the mounting portions 35a-1 and 35b.
-1 and integrated. That is, the U-shaped portion of the adhered member 30 is fitted to the mounting portions 35a-1 and 35b-1, and the fitting convex portion 30b-1 and the concave portion 35-1 are fitted to each other so that The two are stably combined in a fixed positional relationship. At this time, since the screw 36 protrudes from the surface of the doctor blade 35, an escape hole is formed in the corresponding seal mounting plate 30 and the screw 36 is formed utilizing the elasticity of the member to be attached. If the protruding portion is fitted in the hole, the protrusion can be prevented from coming off and the integrated state can be maintained.

In this manner, the adherend 30, the doctor blade 35 and the developing roller are integrated. The shafts 34a and 34b are supported by side plates (not shown) of the developing device main body. In this state, the member 30 is attached to the shafts 34a, 3a.
It is swingable about 4b as a fulcrum. Therefore, the adhered member 3
As shown in FIG. 8, the sealing sponge material 30S provided in close contact with 0 is oscillated until it comes into pressure contact with the sealing sponge material provided in close contact with the upper casing 2b constituting the developing device main body. In the state of being pressed, the hook 30d is hooked on the projection 38 of the developing device main body and positioned and mounted. At this time, the tip of the entrance seal 33a, which is the middle part of the seal 33, is set to be in a state of lightly sliding on the peripheral surface of the photosensitive drum 1.

The side seal portion 33b of the seal 33 partially covers both ends of the developing roller 5, and is in contact with the upper part of the ear in the region where the state of the ear is attenuated at the end of the magnet group. Prevents toner scattering. Also, the end 33c
Covers the seal member 531 provided in close contact with the support members 35a and 35b, and the photosensitive drum 1 and the seal member 5
31 to reduce the rotational resistance of the photosensitive drum 1.

In FIG. 8, a developing device 22 is integrally formed with a photosensitive case 13 for supporting the photosensitive drum 1,
A photoconductor unit 220 is configured as a part of the image forming apparatus. The photosensitive drum 1 rotating in the clockwise direction is charged by the charging roller 2 first, and is exposed to exposure light 15 including image information to carry an electrostatic latent image thereon. The electrostatic latent image is visualized, and the visible image is transferred to the photosensitive drum 1 and the transfer roller 1.
6 is transferred to a transfer paper passing between the transfer paper 6. The toner image on the transfer paper is fixed on the transfer paper by a fixing device (not shown) and is discharged to a tray. On the other hand, the photosensitive drum 1 after the transfer of the toner image has the residual toner removed by the cleaning blade 17 and is discharged by the discharging light 6. The residual toner scraped off by the cleaning blade 17 falls into a recovery container provided in a part of the photoconductor case 13 and is sent to the axial end of the transport screw by the rotation of the transport screw 20. Is sent to the developing device 22 by the recycling belt 21 provided on the end side. A cycle in which the toner sent to the developing device 22 is mixed with new toner from the toner bottle 18 and sent to the developing roller 5 is repeated.

When the photoconductor unit 220 is used for the first time, the heat seal 9 of the initial developer tank 90 is pulled out, so that the developer including the toner and the carrier is dropped into the developing device 22. When the toner is consumed by the development, the developing device 22 formed above the second member 4
The toner in the toner bottle 18 is replenished from the opening of the toner bottle via a path shown by an arrow so as to supplement the toner consumed by the development. Reference numeral 19 denotes a toner density detection sensor, and the amount of toner supplied from the toner bottle 18 is controlled according to the detection information of the toner density detection sensor 19.

The circulation path of the developer will be described with reference to FIG. The second member 4 is longer (toward the outside) than the first member 3, and a screw is formed in this long portion.
A large number of blades 4h shaped as if the elliptical plate were cut in approximately half at a portion inside the portion where the screw was formed,
The developer is provided obliquely with respect to the axis, and has a function of agitating and transporting the developer in accordance with the rotation of the second member 4. The transport direction due to the rotation of the second member 4 is the direction of arrow A. Similarly, for the first member 3, similar blades 3h are formed corresponding to the arrangement regions of the blades 4h formed on the first member 3. The inclination of the blade 3h formed on the first member 3 is opposite to the inclination of the blade 4h of the second member 4, and the blade 3h is fed in the direction of arrow B according to the rotation.

A partition plate 24 is provided between the first member 3 and the second member 4 so that the first member 3 and the second member 4
And partition. While the developer is sent in the direction of arrow B in response to the rotation of the first member 3, the developer is sent to the developing sleeve 5 a by the magnetic attraction of the developing sleeve 5 a, and the remaining developer is removed from the partition plate 24. The second member 4
Side, and is sent in the direction of arrow A by the second member 4, and moves to the first member 3 from the gap on the back side of the partition plate 24. As described above, the developer is basically circulated in a loop by the first member 3 and the second member 4 with the partition plate 24 interposed therebetween.

The toner is supplied from the toner bottle 18 to the developing device 2
The position at which toner is supplied to 2 is on the screw portion 4 a outside the partition plate 24. The waste toner scraped off from the photoreceptor 1 is sent to the screw portion 4b axially outside the screw portion 4a for reuse by the recycling belt 21. Therefore, the waste toner is fed into the screw portion 4b of the second member 4, and the new toner is fed into the screw portion 4a. The waste toner and the new toner are fed into the developer in the loop circulation path. Then, they are stirred and transported by the blades 4h.

[0032]

According to the first aspect of the present invention, it is possible to prevent the toner from scattering from the end of the developing roller shaft without impairing the assembling property and the disassembling property of the developing roller unit.

According to the second aspect of the present invention, the driving torque of the photosensitive drum is reduced, the wear of the photosensitive layer is prevented, and toner scattering is prevented while maintaining the photosensitive drum in a stable and favorable state. it can.

According to the third aspect of the present invention, since the extension of the entrance seal serves as a sheet member, there is no need to newly provide a sheet member.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a seal portion at a shaft end of a developing roller for explaining an example of the invention according to claim 1;

FIGS. 2 (a) and 2 (b) are cross-sectional views of a seal portion at a shaft end of a developing roller for explaining an example of the invention according to claim 2;

FIG. 3 is a cross-sectional view of a seal portion at a shaft end of a developing roller for explaining an example of the invention according to claim 3;

FIG. 4 is a perspective view illustrating a support member and a seal extracted and described.

FIG. 5 is a diagram illustrating a mutual positional relationship between a photosensitive drum, a developing roller, and a seal.

FIG. 6 is a diagram illustrating a function of a side seal.

7A is an exploded perspective view of a developing roller cartridge, and FIG. 7B is a partial perspective view of an adherend 30. FIG.

FIG. 8 is a sectional view of a photoconductor unit.

FIG. 9 is a perspective view illustrating a main part of the photoconductor unit.

FIG. 10 is a cross-sectional view of a sealing portion at a shaft end of a developing roller for describing a conventional technique.

FIG. 11 is a cross-sectional view of a sealing portion at a shaft end of a developing roller for describing a conventional technique.

FIG. 12 is a cross-sectional view of a sealing portion at a shaft end of a developing roller for describing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor drum 2a Lower case main body 5 Developing roller 35a, 35b Support member 312, 541, 531 Seal member

Claims (3)

[Claims] A photosensitive drum, a developing roller disposed opposite to the photosensitive drum in a predetermined developing area on a peripheral surface of the photosensitive drum, and supporting the photosensitive drum and the developing roller; An image forming apparatus having a case main body, wherein the developing roller is detachably attached to the case main body as a developing roller unit supported by a supporting member that supports both ends in an axial longitudinal direction of the image forming apparatus; A urethane foam-shaped seal member is provided on each of the opposing surfaces of the photoconductor drum and the opposing surfaces of the support member and the case main body for each of the case main bodies. An image forming apparatus characterized in that the developing area is sealed by being sandwiched between a drum, the case body, and the support member. Place. 2. An image forming apparatus according to claim 1, wherein a sheet member having a smaller coefficient of friction than said seal member is interposed between said seal member and said photosensitive drum. apparatus. 3. An image forming apparatus according to claim 2, wherein said sheet member is a part of a part of an entrance seal provided for preventing toner scattering.