JP3758402B2 - Conductive blade for transfer and processing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transfer conductive blade used as a toner image transfer means in an electrophotographic process using a photoconductive phenomenon, which has a tapered surface on the tip side thereof, and a method for processing the tapered surface.
[0002]
[Prior art]
As is well known, the continuous electrophotographic process is performed, for example, as shown in FIG. That is, first, the charger 1 uniformly charges the surface of the rotating drum-shaped photoconductor 2, and then the exposure device 3 applies light to portions other than the image portion on the surface of the photoconductor 2 to remove the charge, thereby removing the image. A considerable electrostatic latent image is formed. In the developing unit 4, charged toner having a polarity opposite to that of the electrostatic latent image adheres according to the pattern of the electrostatic latent image, thereby forming a visible image (toner image).
[0003]
On the other hand, an endless belt 5 circulates and moves slightly below the photosensitive member 2, and a recording material (not shown) conveyed on the belt 5 at an appropriate timing is brought into contact with the back side of the belt 5. A charge having a polarity opposite to the charged polarity of the toner is applied through the transfer means 6. Therefore, the toner image formed on the surface of the photosensitive member 2 is transferred to the surface of the conveyed recording material when it reaches the lower rotational position. Thereafter, the toner image is fixed by the fixing device 7, and the surface of the photoreceptor 2 after the transfer is returned to the initial state by the action of the static eliminator 8 and the cleaner 9, and one cycle of the electrophotographic process is completed.
[0004]
As the transfer means 6 in such an electrophotographic process, a transfer roll method and a conductive blade method are representatively exemplified, but when considering a color photographic image in which future demand is expected to increase, the former method is a recording material. Is pressed against the surface of the photoconductor, the toner images for each color formed in a slightly thick layer may be crushed by the pressure and become unclear. In this respect, the latter method is promising.
[0005]
[Problems to be solved by the invention]
By the way, as shown in FIG. 2, the conductive blade is formed with a tapered surface 11 on the front end side of the rubber main body 10 of the conductive blade, thereby widening the discharge region with a narrow opposing angle at the front end surface of the conductive blade. Thus, the belt 5 is held.
[0006]
However, as a method of forming the taper surface, injection molding of the rubber blade body into a shape having a taper surface in advance requires the necessity of precise design of the mold for accurately injection-molding an extremely thin taper surface portion. It is not an advantageous method from the viewpoint of the technical difficulty of molding, but rather a method of forming a taper surface by cutting a blade body formed into a simple and thin plate by injection molding or the like and thereafter cutting it. However, this is advantageous in terms of cost and ease of implementation technology.
[0007]
Normally, when such a cutting process is performed on a rubber material, for example, as shown in FIG. 3, the blade body 10 is fixed on a pedestal 13 provided with a rubber sheet 12 or the like using a stopper 14 or the like. Then, the cutting blade 15 is applied to the surface of the pedestal 13 from the inclined direction for cutting. However, in the case of such a cutting method, due to the rubber material being an elastic body, the taper surface 11 of the blade body 10 actually has a shape that is recessed in a circular arc shape as shown in FIG. turn into.
[0008]
Therefore, even if the blade body 10 is brought into contact with the belt 5 with a narrow facing angle, the tip 16 of the pointed portion accompanying the formation of the tapered surface 11 contacts the belt 5 as shown in FIG. There was a problem that the line contact state by only cannot be realized.
[0009]
Further, it is of course possible to cut off the tip 16 of such a pointed portion after forming the tapered surface 11 by an appropriate means in a separate process, but the productivity is deteriorated by adding a troublesome separate process. .
[0010]
Accordingly, it is an object of the present invention to provide a tapered conductive blade for transfer in view of the above-described knowledge and to provide an effective and simple processing method for the tapered tip portion.
[0011]
[Means for Solving the Problems]
(Configuration of the first invention)
The structure of the first invention of the present application (the invention described in claim 1) for solving the above-described problems is a transfer conductive blade used for transferring a toner image on a photoreceptor onto a recording material in an electrophotographic process. A taper surface that is flatly cut is formed on the front end side of the rubber blade body in the conductive blade, and the head of the pointed portion associated with the formation of the taper surface is cut into the taper surface. This is a conductive blade for transfer composed of a continuous curved surface that does not bulge outward from the angle.
[0012]
(Configuration of the second invention)
The configuration of the second invention of the present application (the invention according to claim 2) for solving the above-described problem is that the taper surface incision angle in the first invention is such that the taper surface incision start point A and the taper surface blade. This is a transfer conductive blade defined by a line connecting the thickness direction center point B of the main body.
[0013]
(Configuration of the third invention)
The configuration of the third invention of the present application (the invention described in claim 3) for solving the above-described problem is that the front end side of the rubber blade body of the conductive blade for transfer is cut with a cutting blade, and the tapered surface according to the first invention is provided. The pedestal surface for mounting the blade body is provided with a relief groove with an inclination angle corresponding to the cut angle of the tapered surface, and the blade body is positioned on the pedestal surface. A method for processing a conductive blade for transfer, wherein the blade body is cut while a cutting blade entered from a direction along the inclination angle of the escape groove is fitted into the escape groove.
[0014]
(Configuration of the fourth invention)
The structure of the fourth invention of the present application (the invention described in claim 4) for solving the above-described problem is that, in the processing method of the third invention, when the blade body is positioned on the pedestal surface, the rubber retainer having an arbitrary shape is formed. This is a method of processing a conductive blade for transfer, in which the blade body is fixed with a tool.
[0015]
[Operation and effect of the invention]
(Operation and effect of the first invention)
Since the conductive blade for transfer of the first invention has a tapered surface on the tip side of the rubber blade body, the conductive blade is brought into contact with the recording material conveying belt as shown in FIG. The tip surface (taper surface) of the belt can be brought into line contact with the belt surface only at one edge, and the taper surface can be opposed to the belt surface with a narrow width with a narrow facing angle.
[0016]
In addition, since the head portion of the pointed portion accompanying the formation of the tapered surface has a continuous curve that does not bulge outward beyond the cut angle of the tapered surface, the tip of the pointed portion is the belt as shown in FIG. It is possible to avoid the problem that it is impossible to realize a line contact state by only one edge on the surface.
[0017]
(Operation and effect of the second invention)
According to the second invention, one specific shape standard for preventing the head of the pointed portion from contacting the belt surface is presented. In this case, as shown in FIG. 5, the notch starting point A of the taper surface 11 in the blade body 10 and the center point B in the thickness direction of the blade body in the taper surface 11 (the intersection of the center line B1 in the thickness direction and the taper surface 11). This means that the head of the pointed portion does not bulge toward the center of the blade from the line C connecting the
[0018]
Therefore, when the head portion of the pointed portion has the shape 16 shown by a two-dot chain line in FIG. 5, it is bulged toward the blade center side from the line C, and meets the shape standard of the second invention. do not do.
[0019]
(Operation and effect of the third invention)
According to the processing method of the third aspect of the invention, since the blade body is cut while being pushed into the relief groove having the inclined angle by the cutting blade, the taper surface is formed at the same time as the taper surface is formed by one-step cutting with the cutting blade. The pointed part is processed into a shape consisting of a continuous curve with the head automatically cut. In addition, the tapered surface does not have a cross-sectional shape recessed in an arc shape as in the prior art.
[0020]
(Operation and effect of the fourth invention)
When the processing method of the third invention is performed while fixing the blade body with a rubber pressing jig of an arbitrary shape as in the fourth invention, it is said that the displacement of the blade body during processing can be prevented. In addition to the action / effect, the action / effect of the third aspect of the invention can be expressed more reliably.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the first to fourth inventions will be described. In the following, when simply saying “the present invention”, the first to fourth inventions are collectively indicated.
[0022]
[Conductive blade]
The conductive blade according to the present invention is a conductive blade for transfer, that is, a blade used for transferring a toner image formed on a photoconductor to a recording material such as recording paper in an electrophotographic process.
[0023]
Such a conductive blade is usually constituted by using a so-called ion conductive rubber material such as hydrin rubber, urethane rubber, nitrile rubber, etc. However, as long as it exhibits a function as a transfer blade and necessary elasticity or flexibility, other conductive blades may be used. You may comprise using a seed material.
[0024]
The overall shape of the conductive blade is usually formed in an elongated rectangular straight plate shape, but may be formed in any different shape as required. Also, when using the conductive blade, the back side of the recording material transporting belt is crossed across the belt at a position almost directly below the photoreceptor, usually held by a metal holder. Although the material and shape of the holder can be arbitrarily changed as necessary, and the direction and position where the conductive blade is held are not impaired as long as the object of the invention is not impaired. Can be arbitrarily changed.
[0025]
[Tapered surface of conductive blade and its processing]
A tapered surface is formed on the tip side of the conductive blade. The cut angle of the tapered surface with respect to the conductive blade body wall is not particularly limited, but is preferably about 55 to 80 ° (specifically, for example, 60 ° or 75 °).
[0026]
In the present invention, the head of the pointed portion associated with the formation of the tapered surface does not bulge outward from the cut angle of the tapered surface, in other words, a cross section in which the tapered surface is recessed in an arc as a whole. It is required not to have a shape.
[0027]
One specific criterion for satisfying such a tapered surface shape is that, as shown in FIG. 5, the head of the pointed portion has a taper surface cut start point A and the thickness of the blade body on the tapered surface. That is, it does not bulge outward from the line C connecting the direction center point B. However, even if this criterion is not met, there may be one that satisfies the tapered surface shape of the first invention.
[0028]
As long as the tapered surface has a satisfactory shape, the processing method is not limited. For example, a method of forming the blade body by injection molding or the like as a shape originally having a tapered surface, or a method of processing the tapered surface by the method shown in FIG. 3 after the blade body is once formed into a thin plate shape can be employed. When the latter method is used, the tapered surface may have the shape shown in FIG. 4, and in that case, the head of the pointed portion can be cut in a separate process.
[0029]
However, for example, when the cutting apparatus shown in FIG. 6 is used, the shape of the blade main body as shown in FIG. 5, that is, the tapered surface 11 is cut flat, and the tip thereof has a continuous curve. A cut surface cut into a round shape is automatically formed, which is very preferable.
[0030]
The main point of the cutting processing apparatus of FIG. 6 is that a pedestal 17 on which the blade body 10 is placed is provided with a clearance groove 19 for a cutting blade 18 for processing for performing a cutting operation. In this case, the escape groove 19 is provided with a certain inclination angle with respect to the seating surface of the pedestal 17, and the cutting operation of the cutting blade 18 is also performed so as to fit into the escape groove 19 along this inclination angle direction.
[0031]
It is desirable that the blade body 10 is positioned with the stationary jig 20, and it is more preferable that the blade body 10 on the pedestal 17 is cut while being pressed with the rubber pressing jig 20 having an arbitrary shape. .
[0032]
[Coating of conductive blade]
The entire surface of the rubber main body portion of the conductive blade or at least the surface of the constant width portion on the tip side may be covered with a thin coating layer made of a suitable material having low conductivity. The coating layer can be formed by any method, but a simple method of dipping the entire conductive blade or a portion having a constant width on the tip side into the coating solution is preferably used.
[0033]
When the coating layer is formed by the dipping method, there is a possibility that a bulge-like bulging portion due to the pool of the coating liquid may be formed at the lower end of the blade body (tip of the taper surface). When the tip portion of each is cut into an obtuse angle, a bulge-like bulge is formed in this portion with a shape that extends the taper surface, resulting in a tapered surface shape with no problem.
[Brief description of the drawings]
FIG. 1 is a diagram conceptually illustrating a general configuration of an electrophotographic process.
FIG. 2 is a diagram illustrating a contact state of a conductive blade with a belt surface.
FIG. 3 is a diagram illustrating a normal blade processing method.
FIG. 4 is a diagram showing an inappropriate conductive blade and its use state.
FIG. 5 is a diagram showing a preferred conductive blade shape.
FIG. 6 is a diagram illustrating a preferred blade processing method.
[Explanation of symbols]
5 Belt 6 Transfer means 10 Blade body 11 Tapered surface 18 Cutting blade 19 Escape groove

Claims (4)

In the electrophotographic process, a transfer conductive blade used for transferring a toner image on a photoreceptor to a recording material,
A taper surface that is flatly cut is formed on the tip end side of the rubber blade body in the conductive blade, and the head of the pointed portion that accompanies the formation of the taper surface is less than the cut angle of the taper surface. A conductive blade for transfer comprising a continuous curved surface that does not bulge outward.   The cut angle of the taper surface is defined by a line connecting a cut start point A of the taper surface and a thickness direction center point B of the blade body on the taper surface. Conductive blade for transfer. A method of processing a tapered surface according to claim 1 by cutting the front end side of the rubber blade body of the conductive blade for transfer with a cutting blade,
A clearance groove is provided on the pedestal surface for mounting the blade body with an inclination angle corresponding to the cut angle of the tapered surface, and the blade body is positioned on the pedestal surface, so that the inclination angle of the escape groove is set. A method for processing a conductive blade for transfer, comprising cutting a blade body while inserting a cutting blade entered from a direction along the clearance into a relief groove.   4. The method for processing a conductive blade for transfer according to claim 3, wherein when the blade body is positioned on the pedestal surface, the blade body is fixed by a rubber pressing jig having an arbitrary shape.

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