JP2003098903A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device that stabilizes the electrical connection of a photoreceptor terminal, prevents an unpleasant noise during slide contact, and allows the simplification of the shape of the terminal. SOLUTION: Flange projections 511, 512, and 513 and a wall 515 are formed on a flange 502. A plate spring 520 is held by the flange projections 511, 512, and 513. In order to press the flange 502 into a photoreceptor drum 501, the plate spring 520 is prevented from interfering with the photoreceptor drum 501. After the completion of pressing the flange into the drum, a shaft 50 is inserted, thereby bringing the plate spring 520 into elastical pressure contact with the photoreceptor drum 501. The plate spring 520 may be designed so as to be locked by means of a rod-like member 516 or a plate-like member 550.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus having a structure in which a shaft member and a cylindrical member that rotates about the shaft member are electrically connected through a conductive elastic member. It is a thing.

[0002]

2. Description of the Related Art FIGS. 1, 2 and 3 show a mode in which a photosensitive drum 501 as a rotatable cylindrical member including an electrode terminal of a conventional image forming apparatus is driven. Figure 1
Is a side view, FIG. 2 is a plan sectional view, and FIG. 3 is a front sectional view. The shaft 50 of the photosensitive drum 501 is driven by the gear 60 of the motor 20 via the gears 30 and 40. The joint 51 provided on the main body casing side of the shaft 50 meshes with the flange portion 502 of the photoconductor unit 500. The photoconductor unit 500 includes a photoconductor drum 501, and
It is configured to be mounted in the direction of the middle arrow. Also, FIG.
FIG. 3A is a view of the flange portion 502 viewed from the shaft 50 side, and FIG. 3B is a view of the joint 702 viewed from the rotary shaft 70 side.

An elastically bending terminal 80 is in contact with the bearing 57 at one shaft end, and is fixed to the resin housing 10 by screws 81. The terminal 80 is in contact with the shaft 50 through the bearing 57, and the tip of the shaft 50 is shown in FIG.
The one end 504 of the leaf spring 503 elastically abuts, and the bent portion 505 of the leaf spring 503 abuts the inner surface of the photoconductor drum 501 (base pipe). On the other hand, by connecting one end of the terminal 80 to the ground potential portion (metal housing: not shown) of the image forming apparatus main body, the photoconductor drum 501 becomes the ground potential.

Here, the one end 504 of the leaf spring 503 and the bent portion 505 elastically abut the shaft 50 and the photoconductor drum 501, respectively, but their contact points abut only geometrically at a point, and therefore the connection is made. Tends to be unstable. That is, when the curved surfaces are in contact with each other at a right angle, the contact surface at that time is only a point.
No. 4 hits only one point on the curved surface of the cylindrical portion of the photosensitive drum 501.

Further, only one point on the end surface of the bent portion 505 is in contact with the inner surface of the cylindrical portion of the photosensitive drum 501. Strictly speaking, it has a width corresponding to the plate thickness, but if the bending surface of the bending portion 505 is not perpendicular to the inner surface of the photosensitive drum 501 cylinder, it will hit at a point. As described above, when the photosensitive drum 501 and the one end 504 and the bent portion 505 are in contact with each other at only one point, the contact is not reliably followed when the shaft center shakes or vibrates, and the connection is made. There was a problem that it became defective.

Since the number of contact points must be increased in order to stabilize the connection, the number of bent points of the leaf spring must be increased. Further, when the flange portion 502 is press-fitted into the photosensitive drum 501 or when the photosensitive unit 500 is set in the main body, a guide type shape that can be reasonably moved in a fixed direction, that is, a leaf spring is required. It is necessary to bend or cut the end portion shape of 503 so as not to become a resistance when it is combined with a mating component, and the bent portion naturally increases as shown in FIG.

In Japanese Laid-Open Patent Publication No. 11-249495 as well, in order to stably contact the photosensitive drum and the leaf spring,
We have proposed a technology that gives the leaf spring a bent shape. However, increasing the bent shape of the leaf spring complicates the manufacturing process and increases the cost.

Further, in the conventional drawing shown in FIG. 3, the flange portion 502 and the shaft 50 are connected by a joint and integrally rotated, but as another example, the shaft on the main body side does not have a joint member, In some cases, only the positioning function is provided. That is, a gear tooth surface is formed on the outer periphery of the flange portion 502, and the photosensitive drum 501 is rotated by receiving a driving force from a gear adjacent to the gear tooth surface. In such cases,
One end 504 of the terminal is in rotary sliding contact with the positioning shaft. However, the instability of the contacts is disadvantageous as in the case of integral rotation, and if the pressure contact force of the leaf spring is increased to compensate for this, abnormal noise (metal noise) during sliding contact is generated.
There was a problem that abrasion powder was generated.

[0009]

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to stabilize the electrical connection of the photoconductor terminals, prevent abnormal noise during sliding contact, and simplify the shape of the terminals. It is an object of the present invention to provide an excellent image forming apparatus in which cost reduction and environmental load reduction are achieved by making parts reusable.

[0010]

In order to solve the above problems, the present invention according to claim 1 has flexibility from a shaft member serving as a rotation shaft of a rotatable cylindrical member having a flange portion. In an image forming apparatus configured to electrically connect to a cylindrical member via a conductive elastic member, the elastic member elastically abuts the shaft member and the cylindrical member at a plurality of positions in the longitudinal direction to establish electrical conduction. An image forming apparatus is characterized in that a short-side surface is positioned in parallel with a longitudinal direction of a cylindrical member and is held by a flange portion of the cylindrical member. According to a second aspect of the present invention, the image forming apparatus according to the first aspect is characterized in that the elastic member is held by a plurality of protrusions of the flange portion.

According to a third aspect of the present invention, there is provided the image forming apparatus according to the first or second aspect, wherein the plurality of contact points of the elastic member are formed by curved surfaces on the same side.

According to a fourth aspect of the present invention, the flange portion has a hole for inserting the shaft member in the central shaft center portion, and a circular shape portion for inserting the cylindrical member in the outer peripheral portion. 5. The elastic member is arranged such that one end of the elastic member is located inside the outer periphery of the circular shaped portion before the shaft member is inserted and is pressed into contact with the cylindrical member after the shaft member is inserted.
The image forming apparatus according to any one of 1.

According to a fifth aspect of the present invention, the flange portion has a hole for inserting the shaft member in the central shaft center portion, and a circular shape portion for inserting the cylindrical member in the outer peripheral portion. The rod-shaped member is attached to and detached from a part of the circular-shaped portion, and the elastic member is supported by attaching and detached the rod-shaped member. 2. The internal member is located so that the rod member is removed so that the cylindrical member is pressed against the cylindrical member.
The image forming apparatus according to any one of 1 to 3.

According to a sixth aspect of the present invention, the flange portion has a hole for inserting the shaft member in the central shaft center portion, and a circular shape portion for inserting the cylindrical member in the outer peripheral portion. A plate-shaped member is attached to and detached from a part of the circular portion, and the elastic member is supported by attaching and detaching the plate-shaped member. One end of the elastic member has a circular shape when the plate-shaped member is attached. An image forming apparatus according to any one of claims 1 to 3, wherein the image forming apparatus is located inside the outer periphery of the portion and is pressed against the cylindrical member by the movement of the plate member. The present invention according to claim 7 is the image forming apparatus according to claim 6, wherein the plate-shaped member has a constricted portion capable of easily removing an exposed portion from the flange portion after the moving operation. .

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. The form in which the photosensitive drum as a rotatable cylindrical member including the electrode terminals of the image forming apparatus is driven is the same as the conventional one shown in FIGS.

FIG. 5 is a perspective view of the photoconductor unit 500 in a disassembled state. The flange portion 502 has a flange portion hole 514 for positioning the shaft center in the center thereof, and a wall surface portion 515 as a circular shaped portion formed to be press-fitted into the photosensitive drum 501 on the outer periphery thereof. There is. On the other hand, the flange portion 502 is integrally formed to support the leaf spring 520 in the width direction.
11, 512, 513. The positional relationship between them is as shown in FIG.
12) and the distance X between 513 and the thickness x of the leaf spring 520
And are almost the same. The flange projection 513 is provided with a projection 513a in the middle, and the height Z in the drawing is set to be slightly higher than the height z of the leaf spring 520. In addition, the leaf spring portion hole 52 formed in the leaf spring 520
The width y of 0a corresponds to the width Y of the projection 513a provided in the middle of the flange projection 513, and the width Y is slightly larger than y.

The posture when the leaf spring 520 is mounted on the flange portion 502 is determined by the above relationship between (X, Y, Z) and (x, y, z). At this point, the leaf spring bent portion 520b is located above the flange hole 514, and the leaf spring tip portion 520c at the tip is located closer to the center than the cutout portion of the wall surface portion 515. Further, in this state, the flange portion 502 is inserted (press-fitted or adhered) to the photosensitive drum 501, so that the wall surface portion 515 and the leaf spring 520 are not in contact with each other at this point. After that, when the photoconductor unit 500 is mounted on the main body of the image forming apparatus, the shaft 50 moves the flange portion 514.
Since the bent portion 520b of the leaf spring hits the tapered portion 50a of the shaft 50 and is pushed away, the tip end side thereof approaches the inner wall surface of the photoconductor drum 501. Since the leaf spring tip portion 520c at the tip has a dimensional relationship of slightly protruding from the outer periphery of the flange portion 502 when the photoconductor drum 501 is not present when the shaft 50 is inserted, FIG.
As described above, in the state where the photosensitive drum 501 and the flange portion 502 are united, the leaf spring tip portion 520c elastically contacts the inner wall surface of the photosensitive drum 501, and the leaf spring bending portion 520 is formed.
b makes elastic contact with the shaft 50b. This stabilizes the electrical connection to the photoconductor drum 501 with a simple assembling work. Also, by stabilizing the electrical connection,
It is not necessary to unnecessarily increase the pressure of the contact portion, and particularly when the central shaft 50 and the plate spring 5520 are in sliding contact with each other, an effect of eliminating noise (abnormal noise) can be obtained.

In this embodiment, the leaf spring portion 520b,
520c is the surface on the same side of the leaf spring 520, but the shape and
The layout may be changed to another surface. But,
By forming the leaf spring portions 520b and 520c with the same curved surface, it is possible to use only the sag surface (the surface that does not cause burrs) when the outer shape of the leaf spring portion 520 is punched and formed, as a contact point. Since no processing is required, cost can be reduced and good connection can be achieved. Further, the contact portion of the leaf spring tip portion 520c to the photosensitive drum 501 is divided into a plurality of portions as shown in the figure, which improves the stability of the contact.

FIG. 7 and FIG. 8 are perspective views of the photoconductor unit 500 in a disassembled state. The flange portion 502 has a flange portion hole 514 at the center thereof, a wall surface portion 515 on the outer periphery which is press-fitted into the photosensitive drum 501, and a flange portion projection 5.
11, 512, 513. The functions and configurations of the flange protrusions 511, 512, and 513 with respect to the leaf spring 530 are as described above, and description thereof will be omitted.

In FIGS. 7 and 8, the flange portion 502 is provided with a penetrating cylindrical protrusion 517, and a rod member 516 is lightly press-fitted into the hole. The leaf spring 530 supported by the flange protrusions 511, 512, 513 is
Except for the support portion, it is largely divided into two, one leaf spring tip portion 530c elastically abuts the rod member 516, and the other leaf spring tip portion 530b is located above the flange hole portion 514. is doing. In this state, the photosensitive drum 5
When 01 is press-fitted, the leaf spring tip portion 530c is retracted to the inside of the path when the drum 501 is press-fitted.
Not a hindrance. Further, by pulling out and deleting the rod-shaped member 516, there is no retreat of the leaf spring tip portion 530c, and the leaf spring tip portion 530c becomes the photosensitive drum 50.
It comes into elastic contact with the inner surface of 1.

On the other hand, the leaf spring tip portion 530b also comes into contact with the tapered portion 50a initially and then with the portion 50b by the insertion of the shaft 50, so that the shaft 50 is
The leaf spring 530 and the photoconductor drum 501 can be electrically connected to each other. The rod-shaped member 516 may be moved only by the amount by which the leaf spring tip portion 530c is retracted, or may be pulled out from the flange portion 502, but there is an advantage that the rod-shaped member 516 can be reused by pulling it out. . Further, the contact portion of the leaf spring tip portion 530c to the photosensitive drum 501 is divided into a plurality of portions as shown in the figure, which improves the stability of the contact.

9 and 10 are perspective views of the photoconductor unit 500 in a disassembled state. The flange portion 502 has a flange portion hole 514 at the center thereof, a wall surface portion 515 on the outer periphery which is press-fitted into the photosensitive drum 501, and a flange portion projection 5.
11, 512, 513. The functions and configurations of the flange protrusions 511, 512, and 513 with respect to the leaf spring 530 are as described above, and description thereof will be omitted.

The flange portion 502 has a groove portion 51 penetrating therethrough.
8 is provided, and a plate member 550 is lightly press-fitted into the groove. The plate-shaped member 550 is a groove-shaped portion 5 of the flange.
18, a guide portion 550a and a constricted portion 550b.
And have. The plate-shaped member upper side 550d and the plate-shaped member lower side 550e have different widths with the constricted portion 550b as a boundary. Figure 8
Move to the position shown in. In this position, the waist 55
0b is exposed on the lower surface of the flange portion 502 in the figure,
The plate-shaped member lower side 550e is twisted around the constricted portion 550b as an axis to enable separation. The constricted portion 550b has a small cross-sectional area and can be easily separated. At the start of inserting the photosensitive drum 501, the leaf spring tip portion 530c is locked to the upper side 550d of the plate-shaped member, which does not hinder the insertion of the photosensitive drum 501. On the other hand, if the plate member 550 moves to the position of FIG. 10, the leaf spring tip portion 530c
Makes elastic contact with the inner surface of the photosensitive drum 501.

In the above-described embodiment, the shaft 50 and the joint 51 may rotate integrally with the photosensitive drum 501 like the shaft 50 of the conventional drawing, or may not be driven by the motor 20 and have a positioning function. Only a non-rotating spindle type may be used. In this case, the leaf spring 520b or 530
Sliding contact rotation with b.

[0025]

As described above, according to the present invention as set forth in claim 1, the lateral (width) direction surface of the leaf spring is brought into contact with the photosensitive drum and the shaft to electrically short-circuit the surface. Is parallel to the longitudinal (axial) direction of the photoconductor drum and is held by the flange part of the photoconductor, so that the photoconductor drum and the leaf spring, and the shaft and the leaf spring are Therefore, it is possible to provide an image forming apparatus in which the electrical connection is stabilized. Further, according to the present invention as set forth in claim 2, since the leaf spring is held by the plurality of projections of the flange portion, the shape of the leaf spring can be simplified, the cost of parts can be reduced, and the assembly and the variation can be reduced. Therefore, it is possible to provide an image forming apparatus suitable for reuse. Further, according to the present invention as set forth in claim 3, by forming the contacts at a plurality of positions of the leaf spring with the same curved surface, it is possible to reduce the cost of parts and to provide an image forming apparatus in which electrical connection is stabilized. Can be provided. Further, according to the present invention as set forth in any one of claims 4 to 6, the leaf spring does not interfere with the photosensitive drum when the flange portion is press-fitted, and the leaf spring is pressed against the photosensitive drum after the press-fitting is completed. Therefore, it is possible to provide an image forming apparatus that improves the workability of assembly and reduces the environmental load without increasing the number of parts. Further, according to the present invention of claim 7, by providing the constricted portion, it is possible to easily remove the exposed portion of the plate-like member, and to provide an image forming apparatus with further improved assembly workability. be able to.

[Brief description of drawings]

FIG. 1 is a side view showing a form in which a photosensitive drum is driven.

FIG. 2 is a cross-sectional plan view showing a form in which a photosensitive drum is driven.

FIG. 3 is a front sectional view showing a form in which a photosensitive drum is driven.

FIG. 4 is a schematic view showing the shape of a conventional leaf spring.

FIG. 5 is a perspective view showing a configuration of a flange protrusion and a leaf spring in the photoconductor unit of the present invention.

FIG. 6 is an exploded perspective view of a photoconductor unit.

FIG. 7 is an exploded perspective view of a photoconductor unit in which a rod-shaped member is detachable.

FIG. 8 is an exploded perspective view of a photoconductor unit in which a rod-shaped member is detachable.

FIG. 9 is an exploded perspective view of a photoconductor unit in which a plate-shaped member is detachable.

FIG. 10 is an exploded perspective view of a photoconductor unit in which a plate-shaped member is detachable.

[Explanation of symbols]

10 housing 20 motor 30 and 40 gears 50 axes 50a tapered portion 51 joint 57 Bearing 70 rotation axis 80 terminals 81 screws 500 photoconductor unit 501 photoconductor drum 502 flange 503 leaf spring 504 One end (of leaf spring) 505 Bending part (of leaf spring) 511, 512, 513 Flange protrusion 513a protrusion protrusion 514 Flange hole 515 wall surface 516 Bar-shaped member 517 Cylindrical protrusion 518 groove 520 leaf spring 520a hole for leaf spring 520b leaf spring bending part 520c Leaf spring bent part (tip) 530 leaf spring 530a Hole in leaf spring 530b Leaf spring tip 530c Leaf spring tip 550 plate-shaped member 550a guidance section 550b constriction 550c step 550d plate-shaped member upper side 550e Plate member lower side 702 joint

Claims (7)

[Claims] 1. An image forming apparatus having a structure in which a shaft member serving as a rotation shaft of a rotatable cylindrical member having a flange portion is electrically connected to the cylindrical member via a flexible conductive elastic member. The elastic member elastically abuts the shaft member and the cylindrical member at a plurality of positions in the longitudinal direction to electrically short-circuit, and the lateral direction surface is positioned parallel to the longitudinal direction of the cylindrical member. An image forming apparatus characterized in that the image forming apparatus is held by a flange portion of the. 2. The image forming apparatus according to claim 1, wherein the elastic member is held by a plurality of protrusions of the flange portion. 3. The image forming apparatus according to claim 1, wherein the plurality of contact points of the elastic member are formed by curved surfaces on the same side. 4. The flange portion has a hole for inserting a shaft member in a central shaft center portion, a circular shape portion for inserting a cylindrical member in an outer peripheral portion, and one end of the elastic member. 5. The image forming apparatus according to claim 1, wherein before the shaft member is inserted, it is located inside the outer circumference of the circular shaped portion, and after the shaft member is inserted, it is pressed against the cylindrical member. apparatus. 5. The flange portion has a hole for inserting a shaft member in a central shaft center portion, and has a circular shape portion for inserting a cylindrical member in an outer peripheral portion, A part of the rod-shaped member is attached and detached, and the elastic member is supported by attaching and detaching the rod-shaped member. One end of the elastic member is positioned inside the outer periphery of the circular-shaped portion when the rod-shaped member is attached. The image forming apparatus according to any one of claims 1 to 3, wherein the image forming apparatus is detached and brought into pressure contact with the cylindrical member. 6. The flange part has a hole for inserting a shaft member in a central shaft center part, and has a circular shape part for inserting a cylindrical member in an outer peripheral part, The plate-shaped member is attached to and detached from some of the parts, the elastic member is supported by attaching and detaching the plate-shaped member, and one end of the elastic member is positioned inside the outer periphery of the circular-shaped portion when the plate-shaped member is attached. The image forming apparatus according to any one of claims 1 to 3, wherein the plate member is pressed against the cylindrical member by moving. 7. The image forming apparatus according to claim 6, wherein the plate-shaped member has a constricted portion.