JP2005099637A - Substrate for photoreceptor and photoreceptor, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate for a photoreceptor capable of suppressing the deformation which arises at the time of forming a photosensitive layer and the photoreceptor using the same, and an image forming apparatus. <P>SOLUTION: In the substrate A for the photoreceptor equipped with the cylindrical substrate 1 to be deposited with the photosensitive layer 2 on the surface, the internal stress of the cylindrical substrate 1 is set at ≤9.2 MPa. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a photoconductor substrate on which a photosensitive layer such as amorphous silicon is formed, a photoconductor, and an image forming apparatus using the same.

  2. Description of the Related Art Conventionally, image forming apparatuses such as copying machines, LED printers, and laser beam printers are known as apparatuses that form images by an electrophotographic process.

  Such an image forming apparatus has a configuration including a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a charge eliminating unit around the photoreceptor. The electrophotographic process is such that the surface of the photoreceptor is charged by corona charging by a charging means, and the charged photoreceptor is irradiated with light from exposure means such as an LED head to form a predetermined latent image, An image is formed by attaching toner to the photosensitive member with a developing unit, and transferring and fixing the toner image onto a recording sheet using a transferring unit. Thereafter, the surface of the photosensitive member is cleaned by a cleaning unit and a discharging unit. The remaining toner and latent image are removed to complete one cycle.

  On the other hand, in the case of an amorphous silicon photoconductor, for example, in the case of an amorphous silicon photoconductor, the photoconductor incorporated in the above-described image forming apparatus prevents carrier injection on the upper surface of a photoconductor substrate made of an aluminum (hereinafter referred to as Al) alloy. There is known a structure in which an a-Si photosensitive layer formed by sequentially laminating a layer, a photoconductive layer, and a surface protective layer is deposited to a thickness of 10 to 100 μm. The photosensitive member has support means such as flanges inserted in both ends thereof and is rotatably supported by the support means.

  In addition, the manufacturing method of the photosensitive member is formed by first forming an Al alloy into a predetermined cylindrical shape by extruding or extruding and drawing, and forming the outer peripheral portion, inner peripheral portion, both end portions, and the like of the formed cylindrical member. Rough cutting is performed, and the inner diameter portion of the inlay is cut to be processed into a predetermined base shape. Furthermore, in order to give a predetermined surface property to the substrate processed into a substrate shape, finish cutting, various blasting treatments, chemical treatments, etc. are performed, and a degreasing and washing process for removing oil and dirt adhering to the surface is performed. Then, a photoreceptor substrate is obtained.

  Next, an a-Si photosensitive layer is formed to a thickness of 10 to 100 [mu] m on the obtained Al alloy substrate to obtain an electrophotographic photoreceptor (hereinafter referred to as a photoreceptor). The a-Si photosensitive layer is formed, for example, by sequentially laminating a carrier injection blocking layer, a photoconductive layer, and a surface protective layer from the substrate side by plasma CVD.

  By the way, in recent years, the rapid progress of electrophotographic technology has led to an increase in the speed, weight, and resolution of an image forming apparatus. In order to achieve these high performances, Dimensional accuracy of the body and good surface properties of the substrate are required.

The dimensional accuracy of the photoreceptor is greatly influenced by the dimensional accuracy in the extrusion and drawing processes of the Al alloy in the substrate manufacturing process, and the dimensional accuracy in the rough cutting process and the finishing cutting process. This has made it possible to respond sufficiently.
JP 2000-72526 A

  However, for the purpose of improving the adhesion between the Al alloy substrate and the a-Si photosensitive layer and forming a good a-Si photosensitive layer, the substrate temperature is increased (200 ° C. to 300 ° C.) to form the photosensitive layer. Since a film is formed, there arises a problem that the substrate is deformed. In particular, when an inlay portion having an inner diameter larger than that of the central portion is formed at both longitudinal ends of the base body, the inlay portion is likely to be deformed.

  When such deformation of the substrate occurs, the roundness of the substrate itself decreases, causing rotational blurring of the photoreceptor, and as a result, causes a problem of density unevenness in the formed image.

  Therefore, in order to solve the above-mentioned problems, it has been proposed to use a material classified by quality O in JISH0001 as a base material, but even with such measures, it is not sufficient to suppress thermal deformation of the base. It was.

  The present invention has been devised to solve the above-mentioned problems, and an object of the present invention is to provide a substrate for a photoreceptor capable of suppressing deformation of the substrate that occurs when a photosensitive layer is formed, and the same. The object is to provide a photoreceptor and an image forming apparatus.

  The photoconductor substrate of the present invention is characterized in that in the photoconductor substrate comprising a cylindrical substrate on which a photosensitive layer is deposited, the internal stress of the cylindrical substrate is set to 9.2 MPa or less. Is.

  The photoreceptor substrate of the present invention is characterized in that, in the above-described photoreceptor substrate, the cylindrical substrate has an inlay portion having an inner diameter larger than that of a central portion at an end portion. Furthermore, the photoreceptor substrate of the present invention is characterized in that, in the above-described photoreceptor substrate, the thickness of the inlay portion is 0.7 mm to 8 mm.

  Further, the photoreceptor substrate of the present invention is characterized in that, in the above-described photoreceptor substrate, the lower limit of the internal stress of the photoreceptor substrate is set to 0.01 MPa or more.

  Furthermore, the photoreceptor substrate of the present invention is characterized in that, in the above-described photoreceptor substrate, the internal stress of the cylindrical substrate is smaller at both ends than in the longitudinal center.

  On the other hand, the photoreceptor of the present invention is characterized in that a photosensitive layer containing amorphous silicon is provided on the above-mentioned photoreceptor substrate.

  The image forming apparatus of the present invention includes the above-described photoconductor, a support unit for rotatably supporting the photoconductor, a charging unit for applying an electric charge to the surface of the photoconductor, and light to the photoconductor. An exposure unit that forms an electrostatic latent image on the photoconductor by irradiation, a developing unit that attaches toner to the photoconductor, a transfer unit that transfers the toner to a transfer material, and a surface of the photoconductor after the toner is transferred Cleaning means for removing the residual toner, and charge eliminating means for removing the residual electrostatic latent image after the transfer of the toner.

  According to the present invention, since the internal stress of the cylindrical substrate is set to 9.2 MPa or less in the photosensitive substrate including the cylindrical substrate on which the photosensitive layer is deposited, the image formation can be performed at high speed. Even if the operation is performed, density unevenness that is an image defect does not occur, and a high-performance image forming apparatus that can achieve good image formation is realized.

  Further, according to the present invention, the internal stress of the cylindrical substrate is made smaller at both end portions than in the longitudinal central portion, thereby advantageously preventing film peeling of the photosensitive layer starting from both end portions. is there.

  Embodiments of the present invention will be described below with reference to the drawings. 1 is a cross-sectional view of a photoconductor substrate A according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a photoconductor B formed using the photoconductor substrate A of FIG. The photoconductor B has a structure in which the photoconductive layer 2 is deposited on the photoconductor substrate A.

Photoconductor Substrate The photoconductor substrate A is formed of a conductive material such as an Al alloy, a magnesium alloy, SUS, nickel, copper, or brass, or an insulating material such as glass or ceramic coated with the conductive material. A photosensitive layer 2 comprising a carrier injection blocking layer 3, a photoconductive layer 4, a surface protective layer 5 and the like laminated in order is deposited on the upper surface of the cylindrical substrate 1. Functions as a supporting base material to support.

  The photosensitive substrate A (cylindrical substrate 1) has inlay portions 1a having a larger inner diameter than the central portion in the longitudinal direction at both ends in the longitudinal direction. The inlay portion 1a is provided in a step formed at the base of the inlay portion 1a when support means such as a flange for rotatably supporting the photoconductor B is inserted from both ends of the photoconductor. By bringing the portion into contact, the positional relationship between the support means and the photosensitive member B is fixed.

  In such a cylindrical substrate 1, the inner diameter in the spigot part 1a is set to 22 mm to 240 mm, and the area other than the spigot part 1a, that is, the inner diameter in the longitudinal center is set to 20 mm to 232 mm. Moreover, the thickness in the inlay part 1a is set to 0.7 mm-8 mm, respectively, and the thickness in a longitudinal direction center part is set to 0.8 mm-10 mm, respectively.

  The cylindrical substrate 1 constituting the photoreceptor substrate A has an internal stress set to 9.2 MPa or less. For this reason, when the photosensitive layer 2 which will be described in detail later is deposited on the cylindrical substrate 1, the cylindrical substrate 1 is well prevented from being deformed by heat during film formation, and the circular shape of the cylindrical substrate 1 is prevented. The degree can be kept high.

  The internal stress of the cylindrical substrate 1 is preferably 9.2 MPa or less, but the smaller the better, the more preferably 8.5 MPa or less. Further, if the internal stress of the cylindrical substrate 1 is set to be smaller than 0.01 MPa, it takes time for the softening process or the cutting process when forming the cylindrical substrate 1, and the productivity is reduced. It is preferable to set the above.

  The internal stress of the cylindrical substrate 1 is preferably set such that its distribution is high at the longitudinal center and low at both ends. The reason is that if the internal stress is large at both ends, the photosensitive layer 2 is likely to peel off from both ends. Further, since a supporting means such as a flange is inserted into the inlay portion 1a formed at both ends, a large external force is likely to be applied, and if the internal stress is large at both ends, the substrate deformation is likely to occur at the inlay portion 1a. is there.

  Furthermore, the internal stress of the cylindrical substrate 1 may be either a tensile stress or a compressive stress, but is preferably a compressive stress. Whether the internal stress of the cylindrical substrate 1 becomes a tensile stress or a compressive stress depends on conditions such as the film formation method of the photosensitive layer 2, the substrate holding method during film formation, and the film thickness uniformity of the photosensitive layer 2. It is determined.

  In the manufacturing method of the cylindrical substrate 1 described above, when the cylindrical substrate 1 is made of an Al alloy, first, a predetermined cylindrical tube is formed by extruding or extruding and drawing an Al alloy. The base tube is softened by heating at a predetermined temperature for a predetermined time. Next, while the softened tube is rotated about the axis at a predetermined speed, rough cutting is performed using cutting means such as a single crystal diamond, sintered diamond, carbide, or the like, and the inlay portion 1a is cut. Then, it is processed into a predetermined substrate shape. Then, in order to give a predetermined surface property to the substrate processed into a base shape, finish cutting, various blast treatments, chemical treatment, etc. are performed, and a degreasing and washing process for removing oil and dirt attached to the surface is performed. Then, a photoreceptor substrate is obtained. At this time, even if the base shapes are the same, the internal stress accumulated in the cylindrical base body 1 varies greatly depending on the above-described softening method and cutting method. For example, the higher the heating temperature in the softening treatment and the longer the heating time, the smaller the internal stress of the cylindrical substrate 1. Further, the lower the feed speed (moving speed) of the cutting means, the smaller the internal stress of the substrate A for photoreceptors, and the smaller the amount of cutting at one time, the smaller the internal stress. Therefore, for example, when a cutting tool made of single crystal diamond is used as the cutting means, the number of rotations per minute of the raw tube is 600 to 12000 rev / min, and per turn of the cutting means along the longitudinal direction of the raw pipe The cylindrical substrate 1 is processed into a predetermined shape by setting the feed speed of the steel sheet to 0.02 μm / rev to 0.5 μm / rev and suppressing the cutting amount per revolution of the raw tube within 0.8 μm / rev. Is preferred.

Photosensitive layer The photosensitive layer 2 laminated on the above-mentioned photoreceptor substrate A (cylindrical substrate 1) is formed by sequentially laminating a carrier injection blocking layer 3, a photoconductive layer 4, and a surface protective layer 5, for example. Yes.

  As the name suggests, the carrier injection blocking layer 3 is a carrier in the cylindrical substrate 1 (for example, when the surface of the photosensitive layer 2 is positively charged by a charging means described later, the carrier is an electron, and the surface of the photosensitive layer 2 is In the case of being negatively charged, the carrier is a hole) and prevents the photoconductive layer 4 from entering the photoconductive layer 4.

  The carrier injection blocking layer 3 is composed mainly of a-Si: H, and is formed on the entire surface of the cylindrical substrate 1 with a thickness of 0.5 μm to 3 μm. When the carrier injection blocking layer 3 is a positively charged photoconductor that positively charges the surface of the photosensitive layer 2, if a Group IIIa element (such as B) in the periodic table is contained as an impurity, It is possible to form a high potential barrier against electrons as carriers, thereby enhancing the effect of preventing the electrons in the cylindrical substrate 1 from being injected into the photoconductive layer 4. On the other hand, in the case of a negatively charged photoreceptor, the potential barrier against holes can be increased by adding a Va group element (such as P) in the periodic table.

In addition, O may be contained in the carrier injection blocking layer 3, and in this case, the forbidden band width of the carrier injection blocking layer 3 can be increased, and this can also enhance the carrier injection blocking effect. , O can improve the adhesion of the carrier injection blocking layer 3 to the cylindrical substrate 1. However, when O is contained in the carrier injection blocking layer 3, since only O may react with the SiH ₄ gas introduced into the chamber during film formation and cause an explosion, the inert N is simultaneously added. It is preferable to contain.

  On the other hand, the photoconductive layer 4 deposited on the carrier injection blocking layer 3 is for generating the above-mentioned carriers inside by irradiation of light from the exposure means, and when such carriers reach the surface of the photosensitive layer. The potential on the surface of the photoconductor is reduced, and an electrostatic latent image is formed on the surface of the photoconductor.

Examples of the material of the photoconductive layer 4 include amorphous materials such as a-Si: H, a-SiC: H, and a-SiO, Se alloys such as Se, Se-Te, and As ₂ Se ₃ , ZnO, CdS, and CdSe. Such as those obtained by dispersing particles of II-VI group compound in a resin, etc., may be formed as a single layer with these materials, or as a plurality of layers divided into a charge generation layer and a charge transport layer Also good.

The photoconductive layer 4 has a dark conductivity (conductivity before light irradiation) set to a small value (conductivity 10 ⁻ ) in order to increase the charge holding capability for holding the charge charged on the surface of the photoreceptor by the action of the charging means. ¹¹ to 10 ⁻¹³ / Ω · cm), and in order to enable the carrier to move smoothly to the surface of the photosensitive layer 2, the light conductivity in the region irradiated with light (conductivity after light irradiation) is relatively large. It is preferable to set to (conductivity 10 ⁻⁶ to 10 ⁻¹⁰ / Ω · cm). The photoconductive layer 4 is formed on the carrier injection blocking layer 3 to a thickness of 15 μm to 80 μm.

  The surface protective layer 5 deposited on the photoconductive layer 4 holds the charge charged by the discharge from the charging means disposed around the photosensitive member on the surface, and from the polishing by the cleaning means to the photoconductive layer. It works to protect 4 etc.

The surface protective layer 5 may have various configurations such as a configuration having a-SiC: H as a main component or a configuration having a-C: H as a main component. In order to retain the charged electric charge on the surface, the difference between the dark conductivity and the light conductivity is small, the conductivity is low (conductivity: 10 ⁻¹² to 10 ⁻¹⁴ / Ω · cm), and the hardness is Vickers hardness Hv It is preferable to form with a material having 1500 or more and an optical band gap of 2.0 eV or more. The surface protective layer 5 has a high resistance when the film thickness is increased, and it is difficult to reduce the surface potential by light irradiation, which may adversely affect the formation of a clear image. The thickness is preferably 3 μm or less, more preferably 0.5 μm to 1.5 μm.

  The difference in internal stress between the photosensitive layer 2 having the carrier injection blocking layer 3, the photoconductive layer 4, and the surface protective layer 5 and the cylindrical substrate 1 is preferably set within 100 MPa. By setting the difference between the two internal stresses, it is possible to suppress the thermal deformation of a small cylindrical substrate having an outer diameter of 40 mm or less.

  Further, it is preferable that the internal stresses of the photosensitive layer 2 and the cylindrical substrate 1 are both compressive stresses. Whether the internal stress of the photosensitive layer 2 is a tensile stress or a compressive stress is determined by conditions such as a substrate holding method at the time of film formation, a film formation method of the photosensitive layer 2, and film thickness uniformity. .

  Further, as a method for adjusting the magnitude of the internal stress of the photosensitive layer 2, it is conceivable to adjust the substrate temperature, the applied power, and the degree of vacuum. For example, to increase the internal stress, the substrate temperature is increased, The applied power may be increased.

  Examples of the method for forming the photosensitive layer 2 include a plasma CVD method, a thermal CVD method, a vacuum deposition method, an ion plating method, a sputtering method (RF, DC, RF magnetron, DC magnetron), a CAT-CVD method, A method such as an active reaction vapor deposition method is conceivable. In the above film forming method, in order to obtain the a-Si photosensitive layer 2 having good adhesion, the film is formed at a high temperature (200 ° C. to 300 ° C.) of the cylindrical substrate 1. Deformation of the film occurs due to thermal deformation or cooling of the photoconductor formed at high temperature to room temperature, resulting in a reduction in dimensional accuracy. This phenomenon becomes more conspicuous as the thickness of the substrate becomes thinner, and the thermal deformation tends to increase in the inlay portion 1a in the cylindrical substrate 1. However, in the present invention, since the internal stress of the cylindrical substrate 1 is set to 9.2 MPa or less, thermal deformation can be suppressed to a low level, and the roundness of the cylindrical substrate 1 can be maintained high. Therefore, it is possible to realize a photoconductor that can be used for image formation with little density unevenness.

Image Forming Apparatus The above-described photoreceptor B is mounted on an image forming apparatus C as shown in FIGS. The image forming apparatus C generally includes a support unit 7, a charging unit 8, an exposure unit 9, a developing unit 10, a transfer unit 11, a cleaning unit 12, and a charge eliminating unit 13. Specifically, the support means 7 is disposed at both ends of the photoconductor B, and the charging means 8, the exposure means 9, the developing means 10, and the transfer means are arranged along the circumferential direction of the photoconductor B. 11, a cleaning unit 12, and a static elimination unit 13 are sequentially arranged.

  The support means 7 disposed at both ends of the photoreceptor B is made of various materials such as Al, resin, SUS, ceramics, etc., and a flange having a disk-like or columnar tip is preferably used. Is inserted into both end portions of the photosensitive member (inlay portion 1a in the present embodiment), so that the photosensitive member B is rotatably supported. It is preferable to set the outer diameter of the support means 7 slightly larger than the inner diameter of the inserted spigot portion 1a from the viewpoint of fixing the photosensitive member B satisfactorily. However, if the diameter is too large, the photosensitive layer 2 may be peeled off. Since it becomes easy to become, it is preferable to set 0.02 mm-0.12 mm larger than the internal diameter of the spigot part 1a.

  The charging means 8 arranged around the photosensitive member B is for applying a charge to the surface of the photosensitive layer 2 of the photosensitive member B to charge the photosensitive layer 2 positively or negatively. For example, a corona charger or a roller charger is used.

  On the other hand, the exposure means 9 arranged on the downstream side of the charging means 8 irradiates the surface of the photoconductor B with light, thereby reducing the potential of the irradiated area and forming a predetermined electrostatic latent image on the photosensitive layer 2. Is to do. When the image forming apparatus is an LED printer, an LED head having a plurality of light emitting diodes arranged substantially parallel to the longitudinal direction of the photosensitive member B is preferably used as the exposure unit 9, and the wavelength of the light is from 600 nm to 740 nm. When the image forming apparatus is a copying machine, a halogen lamp through a filter is preferably used as the exposure unit 9, and the wavelength of the light is 550 nm to 650 nm. On the other hand, when the image forming apparatus is a laser beam printer, as the exposure unit 9, a configuration including a laser element and a polygon mirror for irradiating the photosensitive member B with laser light from the laser element is suitably employed. The wavelength of the light is 600 nm to 800 nm.

  Further, the developing means 10 disposed downstream of the exposure means 9 includes a developer storage container and a developing sleeve, and the developer in the developer storage container is transferred to the surface of the photoreceptor by the developing sleeve. It adheres to the formed electrostatic latent image according to the pattern, and performs the effect | action which makes this visible image. As the developer, a two-component developer or a one-component developer such as a conductive magnetic carrier and an insulating toner or a magnetic insulating toner is preferably used.

  The transfer unit 11 disposed on the downstream side with respect to the developing unit 10 is disposed so as to face the photosensitive member B with the recording paper as the transfer material interposed therebetween, and the toner attached by the developing unit 10 It acts to transfer the image to the recording paper.

  On the other hand, the cleaning means 12 disposed downstream of the transfer means 11 has a cleaning blade made of elastic rubber, and the tip of the blade is in sliding contact with the surface of the photoreceptor. It acts to remove residual toner adhering to the surface of the photoreceptor after toner transfer.

  Further, the neutralizing unit 13 disposed between the cleaning unit 12 and the above-described charging unit 8 exposes the entire surface of the photosensitive member B with strong light so that the electrostatic latent image remaining on the surface of the photosensitive member after toner transfer can be obtained. For example, halogen light or laser light is preferably used.

  Thus, when the image forming apparatus described above performs image formation by the electrophotographic process using the Carlson method, the surface of the photoconductor is charged by the charging unit 8 while the photoconductor B is rotated around the axis by the support unit 7, and The charged photoreceptor is irradiated with light from the exposure unit 9 to form a predetermined electrostatic latent image, and the developing unit 10 is used to attach toner to a pattern corresponding to the electrostatic latent image, and transfer the toner. An image is formed on the recording paper by being transferred onto the recording paper by means 11. The toner and the electrostatic latent image remaining after the toner transfer are removed by the cleaning unit 12 and the charge eliminating unit 13 to complete a series of electrophotographic processes.

  In addition, this invention is not limited to the above-mentioned embodiment, A various change and improvement are possible in the range which does not deviate from the summary of this invention.

  For example, in the above-described embodiment, an amorphous material is mainly used as the photosensitive layer 2 of the photoreceptor B. However, instead of this, an organic material may be used as the photosensitive layer 2, and in this case, the photosensitive layer 2 includes a charge generation layer and a charge transport layer. As the charge generation layer, a phthalocyanine pigment, a quinone pigment, an azo pigment or the like is used. As the charge transport layer, an oxadiazol compound, an organic silane compound, or a naphthoquinone is used. Organic and pyrazoline-based organic materials are used.

  In the above-described embodiment, the photosensitive layer 2 has a three-layer structure including the carrier injection blocking layer 3, the photoconductive layer 4, and the surface protective layer 5, but light absorption is performed between the carrier injection blocking layer 3 and the cylindrical substrate 1. A layer may be interposed, or a surface protective layer may be formed in a plurality of layers. In the former case, it is particularly effective when the image forming apparatus is used as a laser beam printer.

  Hereinafter, in order to confirm the effect of this invention, it demonstrates using an Example. These examples are for explaining a preferred embodiment of the present invention, and the present invention is not limited thereby.

なお、内部応力の測定方法としては、下記式にて内部応力を表現するＣｒａｍｐｔｏｎ法を用いた。すなわち、内径を測定した各感光体サンプルを、図５に示す如く、長手方向にわたって切断するとともに、切断後の内径を測定し、最外表面の円周応力を求め、この値を内部応力とした。縦弾性係数Ｅは７１７００ＭＰａ、ポアソン比νを０．３３として計算した。

真円度変化量は、感光層形成前の感光体用基体、並びに感光層形成後の感光体に関して、両端部に存在するインロー部で切断し、該切断面の最外周５箇所で真円度を測定し、各箇所において「感光体真円度−感光体用基体真円度」を算出し、その算出結果の最大値と定義した。なお、真円度の測定は、（株）ミツトヨ製ＲＯＵＮＤ ＴＥＳＴ ＲＡ−４００真円度測定器を用いて行った。 In this example, a cylindrical element pipe is formed by extrusion and drawing of an Al alloy having a purity of 99.9%, and various softening treatments and cutting processes are performed on the element pipe under the conditions shown in Table 1. To form a plurality of photoconductor substrates, and form a photosensitive layer in which a carrier injection blocking layer, a photoconductive layer, and a surface protective layer are sequentially laminated on each substrate under the conditions shown in Table 2. Photoconductor samples (No. 1 to No. 6) were prepared. The outer diameter of the photoreceptor is 84 mm. And each sample No. 1-No. In addition to measuring the internal stress and the amount of change in roundness for No. 6, each sample was mounted in an image forming apparatus to form an image, and the density unevenness of the formed image was evaluated. An LED printer was used as the image forming apparatus, and the wavelength of the light from the LED head was 685 nm. The rotational speed of the photoconductor during image formation was 100 mm / sec.

In addition, as a measuring method of internal stress, Clampton method which expresses internal stress by the following formula was used. That is, each photoconductor sample whose inner diameter was measured was cut in the longitudinal direction as shown in FIG. 5, and the inner diameter after cutting was measured to determine the circumferential stress on the outermost surface, and this value was used as the internal stress. . The longitudinal elastic modulus E was calculated as 71700 MPa and the Poisson's ratio ν was 0.33.

The amount of change in roundness is the degree of roundness at the five outermost circumferences of the cut surface of the photoreceptor substrate before formation of the photosensitive layer and the photoreceptor after formation of the photosensitive layer. Was measured, and “photoreceptor roundness−photoreceptor roundness” was calculated at each location, and defined as the maximum value of the calculation results. In addition, the measurement of roundness was performed using Mitutoyo Corporation ROUND TEST RA-400 roundness measuring device.

表３によれば、内部応力を９．２ＭＰａ以下となったサンプルＮｏ．２〜Ｎｏ．６については真円度変化量が小さく、形成画像の濃度ムラも比較的少なかった。特に内部応力が８．５ＭＰａ以下のサンプルＮｏ．４〜Ｎｏ．６については特に濃度ムラが少なかった。従って、良好な画像を得るためには感光体用基体の内部応力を９．２ＭＰａ以下に設定すればよいことがわかる。 The presence / absence of density unevenness was evaluated by three steps: visually observing the formed image, ○: almost no density unevenness, Δ: little density unevenness, and x: much density unevenness. The above measurement results are shown in Table 3.

According to Table 3, the sample No. whose internal stress was 9.2 MPa or less. 2-No. For No. 6, the change in roundness was small, and the density unevenness of the formed image was relatively small. In particular, sample No. with an internal stress of 8.5 MPa or less. 4-No. For No. 6, the density unevenness was particularly small. Therefore, it can be seen that the internal stress of the photoreceptor substrate may be set to 9.2 MPa or less in order to obtain a good image.

1 is a cross-sectional view of a photoreceptor substrate according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a photoconductor configured using the photoconductor substrate of FIG. 1. It is a schematic block diagram of the image forming apparatus comprised using the photoconductor of FIG. FIG. 3 is a cross-sectional view showing an arrangement state of the photosensitive member and supporting means of FIG. 2. It is a figure for demonstrating the measuring method of an internal stress.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cylindrical base | substrate 1a ... Inlay part 2 ... Photosensitive layer 3 ... Carrier injection | pouring prevention layer 4 ... Photoconductive layer 5 ... Surface protective layer 7 ... Charging means 8 ... Supporting means 9 ... exposure means 10 ... developing means 11 ... transfer means 12 ... cleaning means 13 ... static means A ... photosensitive substrate B ... photosensitive body C ...・ Image forming device

Claims (7)

A photoconductor substrate comprising a cylindrical substrate on which a photosensitive layer is deposited, wherein the internal stress of the cylindrical substrate is set to 9.2 MPa or less. 2. The substrate for a photoreceptor according to claim 1, wherein the cylindrical substrate has inlay portions having an inner diameter larger than that of the central portion at both ends in the longitudinal direction. The photoreceptor substrate according to claim 2, wherein a thickness of the inlay portion is 0.7 mm to 8 mm. 4. The photoreceptor substrate according to claim 1, wherein a lower limit value of internal stress of the cylindrical substrate is set to 0.01 MPa or more. 5. The photoreceptor substrate according to claim 1, wherein an internal stress of the cylindrical substrate is smaller at both end portions than in a longitudinal central portion. 6. A photoconductor comprising a photosensitive layer containing amorphous silicon on the photoconductor substrate according to any one of claims 1 to 5. 7. The photosensitive member according to claim 6, a supporting unit for rotatably supporting the photosensitive member, a charging unit for applying an electric charge to the surface of the photosensitive member, and irradiating the photosensitive member with light. An exposure unit that forms an electrostatic latent image on the surface, a developing unit that attaches toner to the photoconductor, a transfer unit that transfers the toner to a transfer material, and residual toner on the surface of the photoconductor after the toner is transferred. An image forming apparatus comprising: a cleaning unit that removes the residual electrostatic latent image after transferring the toner.

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