JP2011215276A - Charged body of image forming apparatus, and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charged body that is easily manufactured, prevents the shape from being changed with time, and can accurately position a grid for a long time.SOLUTION: The charged body is arranged facing a photoreceptor D of the image forming apparatus, and has a grid 121 for controlling the potential of the photoreceptor D. The grid 121 is formed in a circular arc shape along the surface of the photoreceptor D. The charged body includes a flat grid supporting section 122 that is formed around the grid 121 integrally with the grid 121, and supports the grid 121. Both ends of the grid 121 may be connected to the grid supporting section 122 through a connection section 123 formed integrally with the grid 121 and grid supporting section 122.

Description

  The present invention relates to a charged body that is used in an image forming apparatus such as a printer and includes a grid that controls the potential of the surface of a photoreceptor, and a method for manufacturing the same.

In an image forming apparatus such as a printer, a charged body is used to charge the surface of the photoreceptor. The charged body is disposed between a discharge electrode that performs corona discharge and the photosensitive member, and includes a grid that controls a charging potential on the surface of the photosensitive member, and a support member that supports the grid (for example, Patent Document 1). reference).
However, the grid is preferably at a uniform distance from the surface of the photoconductor over its entire width. For example, Patent Document 2 proposes a grid having a curved shape along the surface of the photoconductor.

Japanese Laid-Open Patent Publication No. 8-15556 Japanese Patent No. 4309704

Here, as a method of forming a curved grid as described in the above-mentioned document, generally, a metal charging body on which the grid is formed is made into a curved shape by press molding or the like, or a metal to be a charging body A method of forming a grid after curving the plate can be mentioned.
However, the conventional method described above has the following problems.
(i) If a press molding or the like is performed after forming the grid as in the former method, the grid will be deformed and the distance of the grid to the photoreceptor will not be uniform, and the size and shape of the lattice holes constituting the grid will vary. Reducing charging performance.
(ii) The former method and the latter method are likely to cause distortion in the charged body over time due to internal stress, dead weight, etc. remaining during press molding.
(iii) If both ends of the charged body are pulled and held by a spring or the like, a force that deforms the charged body is exerted by the spring or the like, and the grid distance is made uniform when mounting the charged body facing the photoconductor. It becomes difficult to do.
(iv) The grid described in Patent Document 2 is formed of an elastic material, and is curved so that both side edges of the grid are pressed into the grooves of the first wall portion and the second wall portion, and both the wall portions are elastically pressed. Therefore, the curvature is not constant over the entire curved surface, and the distance between the grid and the upper surface of the photosensitive member varies and the performance is degraded.

  The present invention has been made in view of the above problems, can solve the above problems (i) to (iii) all at once, and does not cause the problems mentioned in the above (iv), A charged body that can be mass-produced with a simple method and at low cost, can maintain a uniform distance between the grid and the photosensitive member over a long period of time, and can maintain high performance over a long period of time. For the purpose of provision.

In order to solve the above-described problem, the invention according to claim 1 is provided with a grid that is disposed to face the photoconductor of the image forming apparatus and controls a potential of the photoconductor, and the grid is a surface of the photoconductor. The charging body is formed in a circular arc shape along the grid and has a flat plate-shaped grid support portion that is formed integrally with the grid around the grid and supports the grid.
According to this configuration, since the grid is formed in an arc shape according to the curvature of the photoconductor, the charged state of the grid with respect to the photoconductor can be made uniform.
Moreover, since the circumference | surroundings of a grid are supported by the flat grid support part, the shape of a grid is maintained over a long period of time by this grid support part. Furthermore, even if both ends of the grid support portion are pulled by a spring or the like, no force can be applied to the grid, and the shape of the grid can be maintained for a long time without distorting the grid.

According to a second aspect of the present invention, both ends of the grid and the grid support part may be connected by a connection part formed integrally with the grid and the grid support part. Various shapes can be selected for the connecting portion. However, as described in claim 3, for example, a three-dimensional shape such as a dome shape matching the curvature of the grid increases the rigidity. be able to.
And by supporting the both ends of a grid with a connection part with high rigidity, the deformation | transformation of a grid can be suppressed over a long term, and the uniformity of a charged state can be maintained over a long term.
Furthermore, in order to increase the rigidity of the grid support portion, as described in claim 4, a ridge portion may be formed on at least a part thereof. For example, the raised portion may be formed on one or both of the opposing long sides of the grid support portion formed in a rectangular shape, or may be formed on one or both of the short sides. You may form over. Examples of the form of the raised portion include those obtained by bending the side edges of the grid support portion, and those obtained by forming convex bumps on the grid support portion.

The charged body having the above-described configuration can be manufactured by the following method.
That is, in the method according to claim 5, the image forming apparatus includes a grid that is arranged to face the photoconductor of the image forming apparatus and controls the electric potential of the photoconductor, and the grid has an arc shape along the surface of the photoconductor. A method of manufacturing a formed charged body, comprising a step of preparing a conductive flat plate as a material of the charged body and shaping the charged body to be formed on the flat plate, and the shaped area of the flat plate A step of forming a bulging portion having a radius of curvature along the surface of the photoconductor by drawing, a step of forming a grid on the bulging portion, and the flat shape around the grid. And a step of taking out the charged body while leaving the grid support portion.

Further, in the method according to claim 6, in the step of forming the bulging portion, a connecting portion that connects both ends of the bulging portion and the grid support portion is formed simultaneously with the bulging portion, and the bulging portion is formed. This is a method of forming a grid in the part. The three-dimensional connecting portion including the dome shape described above is formed simultaneously and integrally with the bulging portion in this step.
Furthermore, the method according to claim 7 is to prepare a jig along the inner shape of the bulging part in advance, and when forming the grid, at least the bulging part is supported from the inner side by the jig. It is a method. According to an eighth aspect of the present invention, after forming a raised portion for increasing rigidity on at least a part of the flat plate serving as the grid support portion, drawing may be performed.
In addition, various methods can be used for forming the grid, and the order of the formation may be before or after the formation of the bulging portion. For example, as described in claim 9, Alternatively, a masking process that is patterned in advance so as to form the grid may be performed, and the grid may be formed by an etching process after the drawing process.
In the present invention, it is ideal that the internal stress (residual stress) of the grid and the grid support portion is 0, and if necessary, heat treatment or the like is performed after forming the bulge portion or the bulge portion. It is preferable to remove the internal stress.

  According to the present invention, it is possible to obtain a charged body that is easy to manufacture and can suppress a change in shape over time, and can position a grid with high accuracy over a long period of time, and a method for manufacturing the same.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
[First embodiment]
1A and 1B are explanatory views of a charged body according to the first embodiment of the present invention. FIG. 1A is a perspective view in which a part of the charged body is omitted, and FIG. 1B is a charged view with the charged body of FIG. FIG. 2 is a diagram illustrating a relationship between a schematic configuration of the apparatus and a photoconductor.
As shown in FIG. 1A, the charging body 12 includes a grid 121 that controls the potential of the photoconductor D of the image forming apparatus, and a flat grid support that is integrally formed with the grid 121 around the grid 121. Part 122.
As shown in FIG. 1B, the charging body 12 is attached to the opening of the case 10 of the charging device 1 that is disposed to face the surface of the photoreceptor D. A wire 11 that generates corona discharge is disposed between the charging body 12 and the bottom of the case 10.

The grid 121 is formed in a curved surface shape according to the curvature of the photoconductor, and is attached to the case 10 so that the distance between the surface of the photoconductor and the grid 121 is uniform over the entire width.
Further, the grid support portion 122 is formed in a flat plate shape so as not to have an internal stress, and by supporting the grid 121 from the periphery, the curvature of the grid 121 is formed with time or by its own weight or a curved surface. The internal stress that may remain is suppressed so as not to change in the diameter reducing direction or the diameter expanding direction.

A plurality of engagement holes 123 are formed at both ends of the grid support portion 122 (in the example of FIG. 1A, two at each of the two ends, a total of four). This engagement hole 123 is for engaging one end of a spring (not shown) for pulling both ends of the charging body 12 and supporting them linearly in the case 10 of the charging device 1.
Since the grid support portion 122 is formed in a flat plate shape as described above, the grid support portion 122 is deformed even when the spring is engaged with the engagement hole 123 and the grid support portion 122 is pulled from both ends. Such a force does not act, and accordingly, a force that deforms the grid 121 does not act.
As described above, the charged body 12 of the present invention can not only suppress the deformation of the grid 121 by supporting the grid 121 from the periphery by the flat grid support portion 122, but also can connect the grid 121 to the charging device 1. Also when attaching, force can be prevented from acting on the grid 121, and the shape of the grid 121 can be maintained constant over a long period of time.

The charged body 12 shown in FIG. 1A can be manufactured according to the procedure shown in FIG.
First, a metal plate P such as stainless steel, which is a material for forming the charged body 12, is prepared. In this case, after forming a plurality of charged bodies 12 on a large metal plate P or after forming a plurality of bulging portions Pb described later, the individual charged bodies 12 may be cut out or punched. Since the possibility of internal stress remaining in the charged body 12 increases as the number of plastic processing steps increases in the subsequent process, the metal plate P is formed in a size that matches the charged body 12 in advance as shown in the example in the figure. It is preferable to remove the internal stress by performing a heat treatment or the like as necessary.

  In the example of FIG. 2, the metal plate P is preliminarily formed with cuts Pa for forming openings in the portions that become both ends of the grid 121. In this embodiment, the metal plate P is previously masked for grid formation. The masking may be formed after the bulging portion Pb described below is formed, but in the flat plate state, it can be easily performed using existing equipment, and mass production is also possible. However, in this case, masking is formed after the shape and size of each lattice are determined in advance according to the curvature of the bulging portion Pb so that the size and shape of each lattice constituting the grid are uniform. There is a need to.

The metal plate P is set in a drawing machine, and the center portion is drawn while pressing the periphery of the metal plate P to form a curved bulge portion Pb as shown in FIG. At this time, the engagement hole 123 may be formed at the same time.
After the bulging portion Pb is formed, heat treatment is performed as necessary to remove internal stress.
Thereafter, as shown in FIG. 2C, the bulging portion Pb is subjected to a process such as an etching process to form a grid.
When performing heat treatment or grid formation, a jig 15 as shown in FIG. 2 (c) formed in accordance with the shape of the bulging portion Pb is used as necessary. The part Pb may be supported so as not to be deformed by its own weight.
Thus, the charged body 12 shown in FIG. 1 is formed.

3A and 3B are explanatory views of the charged body according to the second embodiment of the present invention. FIG. 3A is a perspective view in which a part of the charged body is omitted, and FIG. 3B is a cross-sectional view of the bent portion of FIG. is there.
In the charging body 22 according to this embodiment, vertical planar connecting portions 224 are formed at both ends of a curved grid 221, and the flat grid support 222 and both ends of the grid 221 are connected.
Further, the periphery of the long side of the grid support part 222 is bent to form a bent part 222a which is a raised part, and the rigidity of the grid support part 222 is increased. The bent portion 222a may be formed by bending the grid 221 on the side opposite to the bulging side, but it is formed by bending the side opposite to the photoconductor D, that is, on the same side as the bulging side of the grid 221. It is preferable that
The charged body 22 of this embodiment can be formed in substantially the same procedure as the charged body 12 of the previous embodiment, but the notch Pa is not formed in the metal plate P in order to form the connecting portion 224. Further, it is preferable to form the bent portion 222a before drawing.

FIG. 4 is a perspective view in which a part of the overall configuration of the charged body according to the second embodiment of the present invention is omitted.
In the charging body 32 of this embodiment, dome-shaped connection portions 324 are formed at both ends of a curved grid 321, and the plate-shaped grid support portion 322 and both ends of the grid 321 are connected.
It is preferable that no grid is formed on the connecting portion 324 in order to maintain the rigidity of the connecting portion 324 high.

The charging body 32 configured as described above can integrally form the grid 321, the grid support portion 322, and the connecting portion 324 by the same drawing process as that of the charging body 12 of the previous embodiment.
The charging body 32 of this embodiment has a possibility that the entire length of the charging body 32 is longer than the charging body 12 of the previous embodiment by the amount of the dome-shaped connecting portion 324. Since both ends are supported by a dome-shaped connecting portion 324 having high rigidity, there is an advantage that the shape of the grid 321 can be stably maintained over a long period of time compared to the charged body 12 of the previous embodiment.

Although a preferred embodiment of the present invention has been described, the present invention is not limited to the above-described embodiment.
For example, in the description of the second embodiment, the bent portion 222a is given as an example of the raised portion. However, if the rigidity of the grid support portion can be increased, the raised portion is part of the grid support portion. The convex part which bulged and formed may be sufficient. Further, the raised portion is not limited to a part of the grid support portion 222 and may be formed over the entire circumference, for example.
Furthermore, although the shape of the connecting rods 224 and 324 has been described as a vertical surface in the second embodiment and a dome shape in the third embodiment, the both ends of the grid and the grid support are connected integrally. As long as the rigidity of the grid can be increased, the form is not limited to the above-described form, and may be a flat form or a solid form of another form.

  The charged body of the present invention is not limited to a printer, and can be applied to all types of image forming apparatuses that include a photoreceptor and a grid to form an image, such as a copying machine or a FAX.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing of the charging body concerning 1st embodiment of this invention, (a) is a perspective view which abbreviate | omitted a part of charging body, (b) is schematic structure of the charging device which attached the charging body of (a). FIG. It is a figure which shows an example of the manufacturing method of a charging body. It is explanatory drawing of the charging body concerning 2nd embodiment of this invention, (a) is the perspective view which abbreviate | omitted a part of charging body, (b) is sectional drawing of the bending part of (a). It is the perspective view which abbreviate | omitted one part explaining the whole structure of the charging body concerning 3rd embodiment of this invention.

DESCRIPTION OF SYMBOLS 1 Charging apparatus 10 Case 11 Wire 12 Charged body 121 Grid 122 Grid support part 123 Engagement hole 22 Charged body 221 Grid 222 Grid support part 222a Bending part (raised part)
224 connection part 32 charged body 321 grid 322 grid support part 324 connection part

Claims (9)

In a charged body that is disposed to face a photoreceptor of an image forming apparatus, includes a grid that controls the potential of the photoreceptor, and the grid is formed in an arc shape along the surface of the photoreceptor.
Around the grid, having a flat grid support portion that is formed integrally with the grid and supports the grid,
A charged body characterized by. The charged body according to claim 1, wherein both ends of the grid and the grid support portion are connected by a connection portion formed integrally with the grid and the grid support portion. The charged body according to claim 2, wherein the connecting portion is formed in a dome shape. The charged body according to claim 1, wherein a raised portion for increasing rigidity is formed on at least a part of the grid support portion. A method of manufacturing a charged body, comprising a grid disposed opposite to a photoreceptor of an image forming apparatus and controlling a potential of the photoreceptor, wherein the grid is formed in an arc shape along a surface of the photoreceptor. ,
Preparing a conductive flat plate as a material of the charged body, and taking a shape of the charged body to be formed on the flat plate;
Forming a bulging portion having a radius of curvature along the surface of the photosensitive member by drawing in the shaped region of the flat plate;
Forming a grid in the bulging portion;
Removing the charged body leaving the flat portion around the grid;
A method for producing a charged body, comprising: In the step of forming the bulging portion, the bulging portion and the connecting portions at both ends of the bulging portion are formed simultaneously,
Forming a grid on the bulging portion or the bulging portion and the connecting portion;
The method for producing a charged body according to claim 5. The jig according to the inner shape of the bulging part is prepared in advance, and the bulging part is supported from the inner side by the jig when the grid is formed. The manufacturing method of the charging body of description. 8. The flat plate is subjected to a masking process that is pre-patterned so as to have the shape of the grid, and after the drawing process, the grid is formed by an etching process. The manufacturing method of the charging body of description. The charged body according to any one of claims 5 to 8, wherein a drawing process is performed after a raised portion for increasing rigidity is formed on at least a part of the flat plate to be the grid support portion. Method.

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