JPH06348189A - Image forming device - Google Patents

Abstract

PURPOSE:To provide an image forming device whereby interference of a developing roller with a thin plate can be avoided when a developing unit is mounted and dismounted. CONSTITUTION:In an image forming device, a developing area is set near the bent part of a belt photosensitive body 5 which is provided on a main body and wound on multiple support rollers 1 and 2, a developing roller is installed detachably in the developing area together with a developing unit, the detaching direction is set in the axial direction of the support rollers 1 and 2, and a thin plate 24 of synthetic resin is installed in the developing area at both ends of the photosensitive body so that one end of them is supported by the main body and the free end is located between the photosensitive body part on a first support roller 1 as one of the support rollers and the developing roller. Also cuts 25R and 25L for increasing adhesiveness to the photosensitive body 5 are made in a part of the thin plate 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus.

[0002]

2. Description of the Related Art There is an image forming apparatus as shown in FIG.
In FIG. 9, a belt-shaped photoconductor 5 is wound around a plurality of support rollers 1, 2, 3, 4 on the main body side of the image forming apparatus.

The photoconductor 5 is adapted to be rotated in the direction of the arrow, and when the support roller 1 is particularly called a first support roller, the photoconductor is bent at the portion of the first support roller 1. Forming a part.

The vicinity of the curved portion is set as a developing area 6, and the developing roller 7 is brought into contact with the developing area 6. This developing roller 7 is designated by reference numeral 8 in FIG.
It can be attached to and detached from the image forming apparatus together with the developing unit indicated by.

The attaching and detaching direction of the developing unit is parallel to the axial direction of the first supporting roller 1, and is attached and detached at the time of toner replacement and maintenance.

In FIG. 9, a grid 9 and a charger 10 are attached to the main body side above the photosensitive member immediately upstream of the first supporting roller 1. At the time of image formation, the photoconductor 5 charged by the charger 10 is exposed by the optical image indicated by the arrow 11 in the exposure portion located on the photoconductor portion on the first support roller 1 to carry an electrostatic latent image. .

The latent image is visualized in the developing area 6 by the one-component developer supplied by the developing roller 7, and is transferred to a transfer paper at the transfer portion between the support rollers 2 and 3.

After the transfer, the photosensitive member is a cleaning unit 1.
It is cleaned while passing through two parts and is ready for the next image formation.

To achieve such a developing function, the developing roller 7 is in contact with the photoconductor 5, but if the developing roller 7 is in contact with the photoconductor in the entire region in the axial direction of the developing roller, the photoconductor is out of the image forming area. There is a problem in that the toner from the developing roller adheres to the entire circumference on both ends, and the toner adheres to the corona wire 10a of the charger 10 via the grid 9 and remarkably deteriorates the discharge performance.

As means for avoiding this, FIG. 9 and FIG.
As shown in FIG. 3, one end of each of the photoconductors 5 is attached to the upper case 13 of the photoconductor unit, and the free ends thereof are attached to the photoconductor portion of the first support roller 1 and the developing roller 7. And thin plates 14a and 14b made of synthetic resin are provided so as to be interposed therebetween.

As described above, by providing the thin plates 14a and 14b, the toner on the developing roller 7 does not transfer to the photoconductor at both ends of the photoconductor, and therefore, the charging performance of the corona wire 10a due to the toner adhesion is reduced. The decline is avoided.

As shown in FIG. 12, the developing unit 8 is detachably attached to the main body of the image forming apparatus by being guided in the axial direction 15 of the supporting roller by a guide means (not shown).

A photosensitive member 5 and a supporting roller for supporting the photosensitive member 5;
The cleaning unit and the like constitute the photoconductor unit 16, which is also detachable from the main body of the image forming apparatus.
Here, it is assumed that it is already attached to the main body,
Therefore, it is substantially integrated with the main body.

In FIG. 12, the movable table 17 is provided on the main body and is urged by a spring 18 in a direction away from the photoconductor unit 16. When mounting the developing unit 8 on the main body, first, the developing unit 8 may be mounted on the movable table 17.

That is, the developing unit 8 is mounted on the moving table 17 while being guided by the moving table 17. By rotating the lever 19 after mounting on the movable table 17, the developing unit 8 is moved in the direction of the arrow 20 as shown by the chain double-dashed line, and the developing roller 7 is exposed to light as shown by the solid line in FIG. Body 5
Is in contact with. Note that in FIG. 12, the distance between the photoconductor unit 16 and the movable table 17 is shown separated from the actual one in order to avoid complication.

As described above, the developing unit is mounted on the main body side in a state where the developing roller 7 is separated from the photoconductor 5, and after the mounting, the developing roller 7 is brought into contact with the photoconductor 5 by the rotation of the lever 19. This is to prevent the developing roller 7 from interfering with the photosensitive member 5 and damaging the photosensitive member when the developing unit is mounted.

[0017]

By the way, the thin plate 14a is provided.
(The same applies to the thin plate 14b, so
Only a will be described. ), Under the condition that the developing roller 7 is not present, one end side is attached to the upper case 13 and the other end side is the support roller 1 as shown in FIGS.
Since the thin plate itself largely wraps around in the form of an overhang and is interposed between the lower case 21 of the photoconductor unit and the photoconductor, the thin plate is largely bent due to the so-called waist strength, and the developing region The portion 6 does not come into close contact with the photoconductor 5.

Under such a condition, when the developing unit 8 is mounted along the movable table, the end surface of the developing roller 7 interferes with the thin plate 14a which is largely curved and is largely separated from the photosensitive member. There is a problem that the thin plate 14a is damaged.

However, if the stroke of the movable table 17 in the direction of the arrow 20 is increased, this problem is solved, but if the stroke is increased, the space is increased and the machine cannot be downsized.

Accordingly, it is an object of the present invention to provide an image forming apparatus having a thin plate which can prevent the developing roller from interfering with the thin plate when the developing unit is attached and detached.

[0021]

In order to achieve the above object, the present invention has the following constitution.

(1). A notch for enhancing adhesion to the photoconductor was made in a part of the thin plate (claim 1).

(2). In (1), the notch has a starting point on the vicinity of the axis of the first supporting roller and reaches the horizontal end or the upper end (claim 2).

[0024]

The function of the thin plate is reduced at the cut portion.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1, 2 and 4, a thin plate 24a on the left side has a starting point in the vicinity of an axis O ₁ -O ₁ of a supporting roller 1, and the thin plate 24a faces upward from this starting point. Notches 25R and 25L were formed to reach the upper end of the waist.

The constricted portion has a width between the notches 25R and 25L and is connected to the support portion H extending in the horizontal direction.

By making such a notch, the curved portion of the thin plate 24a becomes the interval width between the notches 25R and 25L, and the waist strength is reduced.

As for the thin plate 24b on the right side, as shown in FIG. 2, by forming the cuts 26R and 26L as in the thin plate 24a, the waist strength of the bent portion is reduced.

As shown in FIG. 2, the inner space W ₁ between the thin plates 24a and 24b is smaller than the width W ₂ of the developing roller 7 and larger than the image W ₃ and the transfer paper width W ₄ .

As described above, the thin plates 24a and 24b are bent and deformed following the outer peripheral surface of the support roller 1 from the starting point,
A state in which the photoreceptor 5 is in close contact is obtained. Therefore, the thin plate does not interfere with the end surface of the developing roller when the developing unit is mounted.

Further, since the thin plate portions are provided on both sides of the cut in the horizontal direction, the thin plate can have a sufficient width from the end portion of the developing roller to the side plate 28 of the photoconductor unit, as shown in FIG. As for the outer side plate 28a,
28b, so that toner can be prevented from entering the inside of the photoconductor unit. As for the inner side, it is possible to prevent the toner from adhering to the photoconductor by overlapping the developing roller 7 by a required amount.

In addition to the above example, as a method of making a notch,
There are various examples as shown in FIGS.

In the example of FIG. 5, the axis O _{1 of} the first supporting roller is
-O ₁ has a starting point on the vicinity to form a notch 30L, 30R reach the horizontal edge.

In the example of FIG. 6, in addition to the cuts 30L and 30R in the example of FIG. 6, several cuts are made in parallel with these cuts.

In the example of FIG. 7, the axis O _{1 of} the first support roller is
A notch 31 having a starting point in the vicinity of -O ₁ and turning in the horizontal direction from the middle toward the upper end to reach the horizontal end.
R and 31L are formed.

In the example of FIG. 8, the support portion 32 is cut out by leaving a cut from the starting point toward the end in the horizontal direction in addition to the cut in the example of FIG.

[0037]

According to the present invention, it is possible to prevent the developing roller from interfering with the thin plate when the developing unit is attached and detached.

[Brief description of drawings]

FIG. 1 is a perspective view of the vicinity of a first support roller illustrating an example of a thin plate according to the present invention.

FIG. 2 is a diagram illustrating the arrangement of a thin plate and members around the thin plate according to the present invention.

FIG. 3 is a side view of a photoconductor unit.

FIG. 4 is a diagram illustrating an example of a thin plate together with a cut.

FIG. 5 is a diagram illustrating an example of a thin plate together with a cut.

FIG. 6 is a diagram illustrating an example of a thin plate together with a cut.

FIG. 7 is a diagram illustrating an example of a thin plate together with a cut.

FIG. 8 is a diagram illustrating an example of a thin plate together with a cut.

FIG. 9 is a side view of the photoconductor unit in which a thin plate in the related art is described together with the photoconductor unit.

FIG. 10 is a front view of a photoconductor unit in which a thin plate in the related art is described together with the photoconductor unit.

FIG. 11 is a perspective view illustrating a slackened state of a thin plate in the related art.

FIG. 12 is a diagram illustrating a mounting unit of a developing unit with respect to a photoconductor unit.

[Explanation of symbols]

 24 thin plate 25R notch 25L notch 30R notch 30L notch 31R notch 31L notch

Claims (2)

[Claims] 1. A developing area is set in the vicinity of a curved portion of a belt-shaped photosensitive member provided on a main body side and wound around a plurality of supporting rollers, and the developing roller is detachably attached to the developing area together with the developing unit. The attachment / detachment direction is the axial direction of the supporting roller, and the developing area and the both ends of the photoconductor are on the first supporting roller which is one end of the supporting roller and the free end of which is supported by the main body. In an image forming apparatus having a thin plate made of synthetic resin which is provided along the curved portion of the photoconductor so as to be interposed between the photoconductor part of the photoconductor and the developing roller, a part of the thin plate adheres to the photoconductor An image forming apparatus having a notch for enhancing sex. 2. The image forming apparatus according to claim 1, wherein the notch has a starting point on the vicinity of the axis of the first supporting roller and reaches a horizontal end or an upper end.