JPH0782264B2 - Corona discharger - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a corona discharger used in an image forming apparatus such as a copying machine.

(Prior Art) In an image forming apparatus such as a copying machine, a corona discharger is used to charge a photoreceptor. A so-called scorotron type corona discharger in which a mesh grid plate is arranged between the photoconductor and the discharge wire is known for the purpose of stabilizing the charging potential on the photoconductor. Usually, the grid plate is attached to a corona discharger and is configured to be insertable into and removable from the main body of the copying machine together with the corona discharger.

By the way, if the corona discharger is used for a long period of time, foreign matter adheres to the discharge wire or the inside of the shield case is contaminated, so that the corona discharger needs to be cleaned regularly.
In that case, it is easier to work by removing the grid plate attached to the corona discharger. In addition, it is of course necessary to reattach the removed grid plate to the corona discharger.

So, attach the grid plate to the corona discharger,
Various proposals have been made in the past for facilitating removal. For example, as shown in Japanese Utility Model Laid-Open No. 62-143961, end blocks for holding a discharge wire are fixedly provided at both ends of a corona discharger, and engaging members of the end blocks are integrally set up. In addition, one of the engaging members is elastically displaceable, and the engaging member is engaged with each of the slits as the engaged portions of the grid plate.

Further, as shown in Japanese Utility Model Laid-Open No. 62-30268, a U-shaped spring member detachably provided to the charger body is provided with an engaging portion so as to engage with one of the slits of the grid plate. Some were made.

(Problem to be Solved by the Invention) However, according to the first conventional corona discharger, the elasticity of one of the engaging members causes the grid plate to be tensioned and stretched. In order to
The distance between the engaging members provided at both ends in the longitudinal direction of the corona discharger must be longer than the distance between the slits provided at both ends of the grid plate. Therefore, when attaching the grid plate to the corona discharger configured as described above, it is necessary to deform the engaging portion made of the elastic protrusion in advance or pull the grid plate inward as much as possible. And it is very troublesome to install. Further, when the grid plate is removed, the operation opposite to the above is performed, and therefore the troublesomeness remains unchanged.

Further, according to the second conventional corona discharger, it is difficult to insert the U-shaped spring member into the charger body while resisting the resilience of the U-shaped spring member. However, the spring force of the spring member may cause the spring member to jump out of the main body. Furthermore, the structure of the corona discharger becomes complicated and the assembly is troublesome.

An object of the present invention is to provide a corona discharger which has a simple structure and in which the grid plate can be easily attached and detached.

(Means for Solving the Problem) That is, according to the first aspect of the present invention, a charger main body, a discharge wire stretched in the charger main body, and a control grid covering at least a part of the discharge wire. The control grid is provided with engaged portions at both ends thereof, and the engaging member engages with the engaged portions of the control grid and supports the engaging members, respectively. At least one of the support members is detachably attached to the charger main body, and at the time of the attachment, the end portion of the support member on the control grid side is the main body of the charger main body. Mounting is performed by abutting on a part of the support member and rotating the support member with the end portion as a fulcrum, and further, for locking one of the support members when mounted on the charger main body. Corona discharger is provided, characterized by comprising a click means.

Further, according to the second aspect of the present invention, the shield case and the end blocks provided at both ends of the shield case are provided, and each of the end blocks has an opening portion and an opening of the end block. A cover member that is detachably attached to cover the portion, a discharge wire stretched between the end blocks, and a control grid that covers at least a part of the discharge wire. An engaging member that has an engaged portion and that engages with the engaged portion is provided, and at least one of the engaging members is provided on the cover member and at least one of the engaging members is provided. The corona discharger is characterized in that it is elastically displaceable in the tension direction of the control grid.

(Operation) When attaching the control grid to the charger body, first, the engaged portion provided at one end of the control grid is engaged with the engaging member, and then the engaged grid provided at the other end of the control grid. The part is engaged with the other engaging member. At this time,
The cover member, which is a support member that supports the other engagement member,
It has been removed from the charger body. Therefore,
Easy to engage. After that, the support member supporting the other engagement member is rotated about one end as a fulcrum to be mounted on the charger main body, and then locked by the locking means.
When the control grid is completely attached to the charger body, the engaging member is elastically displaced, and the control grid is stretched on the charger body with an appropriate tension force.

(Example) Next, the Example of this invention is described with reference to drawings.

In FIGS. 1 and 2, reference numeral 1 indicates a corona discharger. The corona discharger 1 mainly comprises a shield case 2, an end block 3, a discharge wire 4, a cover 6 which constitutes a support member, and a grid plate 20 which constitutes a control grid.

More specifically, the shield case 2 is made of a conductive material and has a U-shaped cross section. End blocks 3 made of an insulating material are provided at both ends of the shield case 2. The shield case 2 and the end block 3 form a charger body. Further, a discharge wire 4 for charging a photoconductor (not shown) is stretched between both end blocks 3 with a predetermined tension by an appropriate means such as a screw 25. The discharge wire 4 is
Connector terminal 26 provided on the end surface of one end block 3
Are electrically connected by known means. The end block 3 is provided with an opening 5 for performing work such as screwing when the discharge wire 4 is stretched. If the corona discharger 1 is inserted into the main body of the copying machine without covering the opening 5 and a high voltage is applied, a disadvantage such as a leak occurs. Can be installed. The cover 6 is provided with a hook 7 that is a second engaging member that constitutes a locking means, and the end block 3 corresponding to the hook 7 is a second engaging member that constitutes a locking means.
A notch 8 that is an engaged portion is provided. This hook 7
The cover 6 is locked to the end block 3 by fitting the notch 8 and the notch 8 together. As shown in FIGS. 1 and 2, the cover 6 includes a base portion 9 having a thickness smaller than that of the cover 6 and a hook-shaped portion 10 continuous from the base portion 9 as shown in FIGS. An engagement member 11 is provided. By forming the hook-shaped portion 10 with a relatively thin wall thickness,
The hook-shaped portion 10 itself is elastically deformed by a force in a direction indicated by an arrow A in the figure. Also, a through hole 12 is formed around the base 9.
By providing, the elastic deformation of the hook-shaped portion 10 itself of the engaging member 11 is made easier. Further, a height regulating member 13 that regulates the height of a grid plate, which will be described later, is connected to the edge of the cover 6 on the discharge region side. That is, the height regulating member 13 keeps the distance between the surface of the photoconductor and the grid plate constant.

The grid plate 20 mainly includes a mesh 21 and a frame body 22. Slits 23, which are engaged portions, are provided at both ends of the frame body 22 in the longitudinal direction. The grid plate 20 is held by the cover 6 by hooking the slit 23 on the hook-shaped portion 10 of the engaging member 11 described above. Further, both longitudinal ends of the frame body 22 are brought into contact with the height regulating member 13 to regulate the height of the grid plate 20.

Next, the operation of mounting the grid plate on the corona discharger main body in which the discharge wire is stretched with an appropriate tension in the configuration of the above embodiment will be described.

First, in FIGS. 2 and 3, the cover 6 is attached to the right end block 3 by engaging the hooks 7 and the notches 8 provided therein. afterwards,
The slit 23 provided at one end of the grid plate 20 has an engaging member 11 on the cover 6 attached to the right end block 3.
Hook on the hooked part 10. The slit 23 provided at the other end of the grid plate 20 is provided with the hook-shaped portion 10 of the engaging member 11 on the other cover 6.
Be hooked on. At this time, the other cover 6 is not yet locked to the end block 3 located on the left side in FIGS. 2 and 3. Then, this other cover 6 is attached to the left end block 3 in FIG. That is, as shown in FIG. 3, the end of the cover 6 on the side of the height regulating member 13 (the end on the grid side) is placed on the end of the left end block 3 on the grid plate side, and the other end of the cover 6 is placed. Is floated from the end block 3. At this time, the grid plate 20 is held between both locking portions without loosening. Further, in this state, the hook-shaped portions 1 of both engaging members 11, 11 are
No elastic deformation occurred in both 0 and 10. Thereafter, the cover 6 placed on the end block 3 is rotated in the direction of arrow B using the end portion of the cover 6 on the side of the height regulating member 13 as a fulcrum so that the hook 7 of the cover 6 and the notch 8 of the end block 3 are removed. Engage them into the state shown in FIG. When the cover 6 is rotated, the hook-shaped portions 10, 10 of the engaging members 11, 11 provided on both covers 6, 6 are gradually narrowed in accordance with the length of the grid plate 20. Elastically deforms. Finally, as shown in FIG. 2, both hook-shaped parts 11, 11 are elastically deformed according to the length of the grid plate 20, and both the height regulating members 13, 13 of the frame body 22 of the grid plate 20. The lower side comes into contact with the grid plate 20 to regulate the height of the grid plate 20, and the grid plate 20 can be stretched and held with an appropriate tension.

Further, it is desirable to remove the grid plate 20 to improve workability when cleaning the inside of the discharge wire 4 or the shield case 2 or reattaching the discharge wire 4 which is regularly performed. At this time, the grid plate 20 can be removed by a reverse operation to the above, that is, a simple operation of removing one cover 6 from the end block 3.

Next, another embodiment of the present invention will be described with reference to FIG. This embodiment differs from the previous embodiments in that one engaging member is attached to the end block instead of being attached to the cover, and the other engaging member is not elastic.

That is, the cover 6a attached to the end block 3a on the right side in FIG. 4 only has the height regulating member 13 of the grid plate 20 and does not have the engaging member. In the case of this embodiment, the engaging member 11 for holding one end of the grid plate 20.
a is provided on the end block 3a fixed to the shield case 2. The engaging member 11a has the same configuration as that described in the previous embodiment, and thus the description thereof is omitted. An engaging member 11b is provided on the other cover 6b attached to the left end block 3b. This engaging member 1
1b has no elasticity.

Next, the operation of attaching the grid plate to the corona discharger in the case of such a configuration will be described. Grid board 20
The slit at one end of must be first attached to the engaging member 11a provided on the right end block 3a. Then, with the cover 6b removed from the left end block 3b, the slits at the other end of the grid plate 20 are engaged with the engaging members 11b. Therefore, the engaging member can be hooked between both engaging members without elastically deforming in advance or pulling the grid plate. Thereafter, the other cover 6b is operated in the same manner as in the above-mentioned embodiment,
Attach to end block 3b. In this embodiment, since the engaging member on one side has elasticity, it is possible to stretch the grid plate with appropriate tension.

Next, referring to FIG. 5, another embodiment of the engaging member according to the present invention is shown.

In the above two embodiments, the engaging member is formed integrally with the cover or the end block, whereas in the case of this embodiment, the engaging member separate from the cover is attached to the cover. It shows an example.

The engaging member 110 of this embodiment is a leaf spring formed by bending a thin metal plate, for example. More specifically, the engagement member 110 includes the hook portion 100 corresponding to the hook-shaped portion 10 and the substrate 90 corresponding to the base portion 9 in the above-described embodiment. The engaging member 110 is attached to the cover 60 as follows. First, the substrate 90 is cut out to form a cut and raised portion 91. Next, the notched portion of the substrate 90 is fitted into the pin 61 provided upright on the cover 60. At this time, the cut-and-raised portion 91 is attached so as to contact the pin 61 from the side opposite to the grid plate 20. Further, the pin 61 is provided with a notch 62, and the tip of the cut and raised portion 91 is inserted,
In FIG. 5, the engagement member 110 is prevented from coming off upward.

The slit 23 provided at the end of the grid plate 20 is hooked on the hook portion 100 of the engaging member 110 thus configured. Then, tension is applied to the grid plate 20 by the spring property of the hook portion 100. In addition, in the case of this embodiment, the cut-and-raised portion 91 also has a spring property and contacts the pin 61 from the side opposite to the grid plate 20, so
The pulling force in the direction indicated by the arrow C in the figure can be more flexibly dealt with.

In the above embodiment, the shield case 2 has a U-shaped cross section, that is, the discharge wire 4 is surrounded by the three wall surfaces 2a, 2b, 2c in FIG. It is not necessary to have it, and it may have two wall surfaces such as a combination of the wall surfaces 2a and 2b, a combination of the wall surfaces 2a and 2c, or a single wall surface such as the wall surface 2c. In short, the shape of the shield case may be appropriately selected according to the copying machine.

In addition, there is a process unit for use in a small-sized copying machine for personal use which has become popular in recent years. In such a process unit, image forming parts such as a photoconductor, a charging part, a developing part, and a cleaning part are unitized, and a casing for enclosing them is generally made of resin. The shield case and the end block of the charging section are integrally formed with this resin casing, and a conductive plate is attached to the back side facing the discharge opening provided on the photoconductor side. Even in the process unit having such a configuration, the present invention can be applied as long as a cover for closing the opening is attached to at least one of the end blocks.

Further, in this embodiment, the height regulating member of the grid plate
Although the structure is such that 13 is connected to the cover 6, the height regulating member 13 may be attached to the end block side or may be integrally formed with the end block. Further, its shape can be changed as appropriate.

Further, in the embodiments of the present specification, an example in which two engaging members are provided on the cover and both are elastic,
And only two examples of the one in which the engaging member on one side is provided on the fixed object and has elasticity and the engaging member on the other side is provided on the cover and does not have elasticity are given, but at least either The present invention can be carried out as long as the engaging member is provided on a detachable support member such as a cover, and at least one of the engaging members has elasticity. Further, if the dimension between the engaged portions of the grid plate and the dimension between both the engaging members are made substantially equal, both engaging members may not have elasticity. Even in this case, as shown in FIG. 3, the grid plate can be easily stretched between the engaging members by attaching the supporting member to the corona discharger with one end of the supporting member supporting one engaging member as a fulcrum. Is possible.

(Effects) Since the corona discharger of the present invention is configured as described above, the control grid can be stretched or removed from the corona discharger very easily. It is also possible to simplify the mechanism for applying tension to the control grid.

[Brief description of drawings]

FIG. 1 is a partially exploded perspective view of a corona discharger according to an embodiment of the present invention. FIG. 2 is a sectional view showing a state where the corona discharger shown in FIG. 1 is assembled. FIG. 3 is a side view showing how to assemble the corona discharger shown in FIG. FIG. 4 is a sectional view of a corona discharger according to another embodiment of the present invention. FIG. 5 is a perspective view showing a part of a corona discharger according to still another embodiment of the present invention. 2 ... Shield case (charger body) 3 ... End block (charger body) 4 ... Discharge wire 6 ... Cover (support member) 7 ... Hook (locking means) 8 ... Notch (locking means) 11 ... ... Engaging member 13 ... Height regulating member 20 ... Grid plate (control grid) 23 ... Slit (engaged part)

Claims (13)

[Claims] 1. A charger main body, a discharge wire stretched in the charger main body, and a control grid that covers at least a part of the discharge wire, and both ends of the control grid are engaged with each other. And a support member for supporting each of the engaged members of the control grid, and at least one of the supporting members. Is detachably mounted on the charger main body, and at the time of mounting, the control grid side end of the support member abuts a part of the charger main body, and the support member is supported by the end as a fulcrum. The corona discharge is characterized by being mounted by rotating, and further comprising locking means for locking when one of the support members is mounted on the charger main body. . 2. The corona discharger according to claim 1, wherein at least one of the engaging members is elastically displaceable in a tension direction of the control grid. 3. The corona discharger according to claim 2, wherein the engagement member is integrally formed with the support member. 4. The corona discharger according to claim 1, wherein the engagement member is a leaf spring member attached to the support member. 5. The corona discharger according to claim 2, wherein the support member is a cover member that covers an end portion of the charger main body. 6. The corona discharger according to claim 1, wherein the support member is further provided with a height restricting member for restricting the height of the control grid. 7. The locking means comprises a second engaging member provided on the support member and a second engaged portion provided on the charger body, the second engaging member being the first engaging member. 2. The corona discharger according to claim 1, wherein the support member is locked to the charger main body by engaging with the engaged portion. 8. A shield case and end blocks provided at both ends of the shield case. Each of the end blocks has an opening, and is detachable to cover the opening of the end block. It comprises a mounted cover member, a discharge wire stretched between the end blocks, and a control grid that covers at least a part of the discharge wire, and both ends of the control grid have engaged parts. An engaging member that engages with each of the engaged parts, at least one of the engaging members is provided on the cover member, and at least one of the engaging members is a tensioning member of the control grid. A corona discharger that is elastically displaceable in any direction. 9. The corona discharger according to claim 8, wherein the engagement member is integrally formed with the cover member. 10. The engagement member is a leaf spring member attached to the cover member.
Corona discharger as described. 11. The corona discharger according to claim 8, wherein the cover member further includes a height restricting member that restricts a height of the control grid. 12. A lock means for locking the cover member when the cover member is attached to the opening of the end block.
Corona discharger as described. 13. The locking means comprises a second engaging member provided on the cover member and a second engaged portion provided on the end block, and an inner end portion of the cover member is provided with the second engaging member. The second end is contacted with the inner end of the end block, and the cover member is rotated around the contact portion as a fulcrum.
The corona discharger according to claim 8, wherein an engagement member is engaged with the second engaged portion to perform locking.