JP2013205692A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoelectric photoreceptor capable of acquiring high rotation accuracy.SOLUTION: The photoelectric photoreceptor comprises: a cylindrical substrate; and a photosensitive layer superposed on an outer peripheral face of the substrate. The substrate includes a fitting portion (11a) that is provided at a cylindrical inner face end of the substrate and the inside diameter of which is notchedly enlarged. The fitting portion includes a site having a slope the inside diameter of which becomes greater from the end face of the substrate towards a center in the cylindrical axis direction. The outside diameter of the substrate is fixed.

Description

  The present invention relates to an electrophotographic photoreceptor used in an image forming apparatus such as a laser printer and a copying machine, and a photoreceptor unit.

  An image forming apparatus such as a laser printer or a copying machine is provided with an electrophotographic photosensitive member. The electrophotographic photosensitive member is a member for transferring contents to be represented such as characters and graphics onto a recording medium such as paper. Such an electrophotographic photosensitive member is configured such that a photosensitive layer is coated on the outer peripheral surface of a conductive cylindrical cylinder formed of aluminum or the like. The photosensitive layer to be coated is appropriately selected depending on the apparatus to which the electrophotographic photoreceptor is applied.

  Both ends of the electrophotographic photosensitive member having a cylindrical shape are provided with flanges that hold the electrophotographic photosensitive member in the image forming apparatus and can rotate the electrophotographic photosensitive member around the cylindrical axis. Accordingly, the electrophotographic photosensitive member is disposed in the image forming apparatus as a photosensitive unit having flanges attached to both ends thereof.

  The flange is attached to the electrophotographic photosensitive member by inserting a part of the flange inside the cylindrical electrophotographic photosensitive member. At this time, a fitting portion is provided in advance on the inner surface of the electrophotographic photosensitive member as a portion for inserting and fitting a flange. The fitting portion is formed by cutting the end portion of the inner surface of the electrophotographic photosensitive member so as to increase the inner diameter, and processing the inner surface from the beginning of the electrophotographic photosensitive member to form a step. The Then, a flange is inserted into the processed part (fitting part).

  Here, the flange has a function of applying a rotational force to the electrophotographic photosensitive member as described above, and greatly affects the rotational accuracy of the electrophotographic photosensitive member. In addition, the rotation of the electrophotographic photosensitive member is required to have extremely high accuracy due to the nature of the image forming apparatus, and is required to be within 20 μm to 100 μm by so-called “shake”. In particular, the larger the outer diameter of the electrophotographic photosensitive member, the more difficult it is to improve the rotation accuracy. Therefore, it is very important that the flange is accurately attached to the electrophotographic photosensitive member.

Patent Document 1 discloses a method of manufacturing an electrophotographic photosensitive member including a step of increasing the inner diameter of an end region of a cylindrical conductive substrate so as to expand toward the end. According to this, it is said that the photoconductor is improved in rotation accuracy and the like and can obtain an electrophotographic image of excellent image quality.
Further, Patent Document 1 shows FIG. 3 (b), and mentions that there is a problem that the flange cannot be mounted or the roundness is deteriorated due to the narrow inner diameter of the end portion of the base. Are described as having problems (paragraph 0050).

JP-A-8-146632

  However, even if the end portion of the electrophotographic photosensitive member is processed and a flange is inserted therein as in the technique described in Patent Document 1, the rotational accuracy of the electrophotographic photosensitive member may not be sufficient. The cause is not necessarily clear, but if the notch at the end of the electrophotographic photosensitive member is widened toward the end as described above, the insertion itself becomes easier, but after the insertion, It is conceivable that the positional relationship between the photoconductor and the flange is not properly maintained. For example, a gap or the like is recognized in a part between the flange and the electrophotographic photosensitive member, and the flange is sometimes inclined and fitted. Even if such a gap is very small, the required rotational accuracy is very high, which may affect the accuracy and needs to be improved.

  In view of the above problems, an object of the present invention is to provide an electrophotographic photosensitive member capable of obtaining high rotational accuracy. Also provided is a photoreceptor unit in which a flange is attached to the end of the electrophotographic photoreceptor.

  The above-described problems of the present invention are solved by the following configuration. Note that reference numerals in the drawings are appended in parentheses for easy understanding, but the present invention is not limited to this.

  The invention described in claim 1 includes a cylindrical substrate and a photosensitive layer laminated on the outer peripheral surface of the substrate, and the substrate is provided at the end of the cylindrical inner surface of the substrate so as to be cut out. Includes a fitting portion (11a) which is a portion having an enlarged inner diameter, and the fitting portion includes a portion provided with an inclination such that the inner diameter increases from the end surface of the base toward the center in the cylindrical axis direction. The electrophotographic photosensitive member (11) has a constant outer diameter.

  According to a second aspect of the present invention, in the electrophotographic photosensitive member (11) according to the first aspect, the inner diameter of the end face of the substrate is the same as the inner diameter of the portion that is not the fitting portion of the substrate.

  A cylindrical substrate; a photosensitive layer laminated on the outer peripheral surface of the substrate; and a flange (12) disposed at an end of the substrate. The substrate is provided at the end of the cylindrical inner surface of the substrate. And has a fitting portion (11a) that is a portion whose inner diameter is enlarged so as to be cut out, and the fitting portion is provided with an inclination such that the inner diameter increases from the end surface of the base toward the center in the cylindrical axis direction. The photoconductor unit (10) includes a portion that is formed, has a constant outer diameter, and is disposed on the base so that the flange is inserted into the fitting portion.

  According to the present invention, shake is suppressed and high rotational accuracy can be obtained. Thus, when arranged in the image forming apparatus, an image with high accuracy is formed.

1 is a diagram conceptually illustrating a structure of an image forming apparatus. It is a perspective view of a photoreceptor unit. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 4 is an exploded view focusing on one end of FIG. 3. It is the figure which showed the other example of the electrophotographic photoreceptor. It is a figure explaining the form of the base | substrate in Example 1. FIG.

  The above-described operation and gain of the present invention will be clarified from embodiments for carrying out the invention described below. Hereinafter, the present invention will be described based on embodiments shown in the drawings. However, the present invention is not limited to these embodiments. In the drawings used for explanation, the shape of each part is exaggerated for easy understanding.

  FIG. 1 is a diagram for explaining one embodiment and conceptually showing an internal structure of an image forming apparatus including a photosensitive unit 10. Examples of the image forming apparatus include a laser printer, a copying machine, and a facsimile.

  The image forming apparatus includes a photoconductor unit 10 (see FIG. 2), a charging roller 1, a developing roller 2, a regulating member 3, a transfer unit 4, and a cleaning blade 5. When a medium such as paper moves along the line indicated by I in FIG. 1, an image is formed on the medium. Each configuration will be described below.

  Characters, figures, and the like to be transferred to a recording medium such as paper are formed on the outer peripheral surface of the photoreceptor unit 10. FIG. 2 is a perspective view of the photoconductor unit 10. 3 shows a cross-sectional view taken along the line III-III in FIG. 2, and FIG. 4 shows an exploded view focusing on one end of FIG.

  As can be seen from FIGS. 2 to 4, the photoconductor unit 10 includes an electrophotographic photoconductor 11 and a flange 12.

  The electrophotographic photoreceptor 11 is a member in which a photosensitive layer is coated on the outer peripheral surface of a cylindrical base. The substrate is a cylindrical body formed of a conductive material such as aluminum. The photosensitive layer formed on the outer peripheral surface of the substrate is not particularly limited, and a known layer can be applied depending on the purpose.

As can be seen from FIGS. 3 and 4, the electrophotographic photosensitive member 11 has fitting portions 11a in which notches are formed at both ends of the cylindrical inner surface of the base so that the inner diameter is enlarged. Is provided. The fitting portion 11a includes a tapered portion inclined so that the inner diameter increases from the end surface of the base of the electrophotographic photosensitive member 11 toward the center in the axial direction of the base. Therefore, in the inclined portion, as shown in FIG. 4, when the inner diameter of the end surface of the base is D ₁ and the inner diameter of the portion located on the center side in the axial direction of the base is D ₂ , D ₁ <D ₂ . Here, D ₁ ≧ D ₃ when the inner diameter of the portion of the substrate that is not the fitting portion is D ₃ .

Further, when the axial length of the fitting portion 11a and the L ₁ (see FIG. 4), the ends of the site where the flange 12 is fitted substrate than (Fig. 3, a portion indicated by II in FIG. 4) Assuming that the inner diameter of the substrate at the position L ₂ where L ₁ > L ₂ on the axial center side is D ₄ , the upper limit is usually 1 mm or less for D ₄ -D ₁ for functional reasons as a product. , Preferably 0.1 mm or less, more preferably 0.03 mm or less. On the other hand, from the viewpoint of suppressing vibration, the lower limit of D ₄ -D ₁ is usually larger than 0 mm, preferably 0.0005 mm or more, and more preferably 0.005 mm or more. The taper angle (inclination angle, the smaller one of the inclination angles with respect to the axial direction of the substrate, θ in FIG. 4) is usually larger than 0 °, preferably 0.010, from the viewpoint of suppressing vibration. More than 0.1 degree, More preferably, it is 0.140 degree or more. For functional reasons as a product, the upper limit of the taper angle is usually 30.00 ° or less, preferably 10.00 ° or less, and more preferably 7.130 ° or less.

Here, since the exaggerated representation is shown in FIGS. 3 and 4, the differences between D ₁ , D ₂ , and D ₄ are also greatly represented, but actually these differences are very small as described above. is there.

Further, the axial length of the fitting portion 11a shown by L ₁ in FIG. 4 is not limited provided that it can mount the flange 12 properly. Thus, L ₁ may be greater than the axial length of the flange engaging portions 12a to be described later.

  On the other hand, the outer diameter of the base of the electrophotographic photosensitive member 11 is preferably constant regardless of the notch of the fitting portion 11a inside the base.

  The base body can be manufactured by forming a cylinder by cutting, extruding, drawing, or the like, and forming the fitting portion 11a by cutting the inner end of the cylinder by cutting. The electrophotographic photosensitive member 11 can be produced by laminating the photosensitive layer on the outer peripheral surface of the substrate.

  The flange 12 is a substantially disk-shaped member made of a metal such as resin or aluminum, and is a member fitted to the fitting portion 11 a of the electrophotographic photosensitive member 11. The flange 12 has a flange-side fitting portion 12a and a shaft portion 12b on which a shaft 12c is formed.

As described above, the flange-side fitting portion 12 a is a portion that is inserted into the fitting portion 11 a of the electrophotographic photosensitive member 11. However, since the flange 12 is held by the end of the electrophotographic photosensitive member 11 by fitting the flange side fitting portion 12a to the fitting portion 11a of the electrophotographic photosensitive member 11, a load is applied at the time of mounting. It is preferable that the pressing is performed by pressing. Therefore, the outer diameter of the flange engaging portions 12a shown in D ₀ in FIG. 4, of the fitting portion 11a of the electrophotographic photosensitive member 11, it is larger than the same or D ₁ and D ₁ is the inner diameter of the end face preferable. That is, D ₀ ≧ D ₁ is preferable.

  The shaft portion 12b is a portion that is formed to be larger than the inner diameter of the base, is disposed so as to be hooked on the end of the base, and is provided with the shaft 12c. The shaft 12c is connected to the rotation shaft of the image forming apparatus, receives the rotational driving force, and rotates the flange 12 and the electrophotographic photoreceptor 11 to which the flange 12 is fitted.

The photoreceptor unit 10 is fabricated by fitting the flange-side fitting portion 12a of the flange 12 into the fitting portion 11a of the electrophotographic photosensitive member 11 described above.
In the present invention, as described above, the notch of the fitting portion 11a is formed so that the inner diameter is enlarged from the axial end portion of the base toward the center, and the flange is fitted therein, so that the electronic Problems such as a gap between the photoconductor and the flange no longer occur. As a result, shake can be reduced, and an electrophotographic photoreceptor and a photoreceptor unit having high rotational accuracy can be obtained.
In particular, due to its nature, it becomes more difficult to increase the rotation accuracy as the electrophotographic photosensitive member has a larger outer diameter and is longer in the axial direction. According to the present invention, the rotational accuracy of such an electrophotographic photosensitive member is also improved. Can produce a remarkable effect.

  In the present embodiment, as shown in FIG. 4, the notch is formed so as to be inclined over the entire length of the fitting portion 11 a in the axial direction. However, the present invention is not limited to this, and it is only necessary to have a notch that is inclined so that the inner diameter expands in a certain section from the end face of the fitting portion. An example is shown in FIG. FIG. 5 is a view of the electrophotographic photosensitive member 11 'viewed from the same viewpoint as FIG. The fitting portion 11′a of the electrophotographic photosensitive member 11 ′ has an inclination such that the inner diameter increases in a certain section from the end face of the electrophotographic photosensitive member 11 ′ toward the center in the axial direction. A constant inner diameter is provided on the axially central side. The present invention may be such an electrophotographic photoreceptor.

  Returning to FIG. 1, the description of the structure of the image forming apparatus will be continued. In addition to the photoreceptor unit 10 as described above, the image forming apparatus includes the charging roller 1, the developing roller 2, the regulating member 3, the transfer unit 4, and the cleaning blade 5, each of which is as follows.

The charging roller 1 charges the electrophotographic photosensitive member 11 by applying a voltage from the image forming apparatus. This is performed by the charging roller 1 rotating following the electrophotographic photosensitive member 11 and contacting the outer peripheral surface of the electrophotographic photosensitive member 11.
The developing roller 2 is a roller that supplies a developer to the electrophotographic photosensitive member 11. Then, the electrostatic latent image formed on the electrophotographic photosensitive member 11 is developed by the developing roller 2. The developing roller 2 includes a fixed magnet.
The regulating member 3 is a member that adjusts the amount of the developer adhering to the outer peripheral surface of the developing roller 2 and gives a triboelectric charge to the developer itself.
The transfer unit 4 is a roller for transferring an image formed on the electrophotographic photoreceptor 11 to a recording medium such as paper.
The cleaning blade 5 is a blade that contacts the outer peripheral surface of the electrophotographic photosensitive member 11 and removes the developer remaining after transfer by the tip thereof.

  Although the main rollers and blades provided in the image forming apparatus have been described here, the members provided in the image forming apparatus are not limited to these, and other members, parts, and development normally provided in the image forming apparatus. An agent or the like is preferably provided.

  Next, the operation of the image forming apparatus will be described. When operating the image forming apparatus, the shaft 12c of the photosensitive unit 10 described above is connected to a rotating shaft provided in the image forming apparatus, and is rotated as necessary. The charging roller 1, the developing roller 2, the transfer unit 4 and the like described above are also mounted so as to rotate as necessary. As a result, the photoreceptor unit 10 rotates and the electrophotographic photoreceptor 11 is charged by the charging roller 1.

  In a state where the photoconductor unit 10 is rotating, the electrophotographic photoconductor 11 is irradiated with laser light corresponding to image information using various optical members, and an electrostatic latent image based on the image information is obtained. This latent image is developed by the developing roller 2.

  On the other hand, a recording medium such as paper is set in another part of the image forming apparatus, is transported to a transfer position by a feed roller, a transport roller, etc. provided in the image forming apparatus, and moves along a line I in FIG. To do. A transfer unit 4 is disposed at the transfer position. A voltage is applied to the transfer unit 4 as the recording medium passes, and an image is transferred from the electrophotographic photosensitive member 11 to the recording medium. Thereafter, the image is fixed to the recording medium by applying heat and pressure to the recording medium. Then, the recording medium on which the image is formed is discharged from the image forming apparatus main body by a discharge roll or the like.

  It can be seen from the operation of the image forming apparatus that the rotation accuracy of the electrophotographic photosensitive member 11 has a great influence on the formed image. According to the present invention, as described above, the rotation accuracy of the electrophotographic photosensitive member can be improved, and the quality of the formed image is also improved.

  The following examples further illustrate the invention. However, the present invention is not limited to the examples.

  In the examples, a test body in which a cut was formed in the inner surface end portion of the electrophotographic photosensitive member was manufactured, and a runout test was performed by fitting a flange. Three types of test bodies were prepared: Example 1 as an example of the present invention, Comparative Example 1 as a conventional example, and Comparative Example 2. In this example, since the photosensitive layer was not affected, the test was conducted only with the substrate.

<Common conditions>
The specifications common to the three types of specimens are as follows.
Base material: Aluminum Flange material: Aluminum

<Conditions of Example 1>
The shape of the fitting part in Example 1 is shown in FIG. In Example 1, a notch is provided such that the inner diameter increases from the end face of the substrate toward the center in the axial direction. Specifically, it is as follows.
・ Axial length L _a1 of fitting part: 12 mm
The inner diameter difference, the endmost portion and the top end portion in 10mm point _D b _-D a: 0.015mm
・ Taper angle α: 0.09 °
・ Number of test specimens: 174

<Conditions of Comparative Example 1>
Although illustration of the fitting part in the comparative example 1 is abbreviate | omitted, it is the following forms. That is, Comparative Example 1 has a notch having a constant inner diameter from the end surface of the base toward the center in the axial direction. Specifically, it is as follows.
・ Axial length L _a2 of fitting part: 12 mm
・ Inner diameter difference from the outermost part at a point 5 mm from the outermost part: 0.00 mm
・ Taper angle: 0.00 °
・ Number of test specimens: 308

<Conditions of Comparative Example 2>
Although illustration of the fitting part in the comparative example 2 is omitted, it has the following form. That is, the comparative example 2 has a notch whose inner diameter decreases from the end surface of the base toward the center in the axial direction. Specifically, it is as follows.
・ Axial length L _a2 of fitting part: 12 mm
-Inner diameter difference from the outermost part at a point 10 mm from the outermost part: -0.015 mm
・ Taper angle: 0.09 °
・ Number of test specimens: 692

<Runout test>
The run-out test was performed by rotating the test bodies according to Example 1, Comparative Example 2, and Comparative Example 3 about the axis and measuring the dimensions using a digital dimension measuring instrument.

<Evaluation>
A runout test was performed on all of the above-described Example 1, Comparative Example 1, and Comparative Example 2. Here, a product with a runout of 20 μm or more was regarded as a defective product, and a product with a runout of less than 20 μm was regarded as a non-defective product. Table 1 shows the results.

  As can be seen from Table 1, the notch of the fitting portion of the first embodiment, that is, the inner diameter increases from the end portion toward the center in the axial direction, and the flange is fitted to the notch (see FIG. (Rotational accuracy) improved.

DESCRIPTION OF SYMBOLS 10 Photosensitive unit 11 Electrophotographic photosensitive member 11a Fitting part 12 Flange 12a Flange side fitting part

Claims (3)

A cylindrical substrate;
A photosensitive layer laminated on the outer peripheral surface of the substrate,
The base has a fitting portion which is provided at the end of the cylindrical inner surface of the base and is a portion whose inner diameter is enlarged so as to be cut out,
The fitting portion includes a portion provided with an inclination such that the inner diameter increases from the end surface of the base toward the center in the cylindrical axis direction,
The outer diameter of the substrate is constant,
Electrophotographic photoreceptor.   The electrophotographic photosensitive member according to claim 1, wherein an inner diameter of the end surface of the base is the same as an inner diameter of a portion of the base that is not the fitting portion. A cylindrical substrate;
A photosensitive layer laminated on the outer peripheral surface of the substrate;
A flange disposed at an end of the base body,
The base has a fitting portion which is provided at the end of the cylindrical inner surface of the base and is a portion whose inner diameter is enlarged so as to be cut out,
The fitting portion includes a portion provided with an inclination such that the inner diameter increases from the end surface of the base toward the center in the cylindrical axis direction,
The outer diameter of the substrate is constant,
The flange is disposed on the base body so as to be inserted into the fitting portion.
Photoconductor unit.

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