JP2010139765A - Method and apparatus for inspecting surface state of elastic body roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for inspecting the surface state of an elastic body roller by which a predetermined depression can be detected even in the celastic body roller configured so that its surface layer is moderately roughened, and the predetermined depression can be detected in every position in the axial direction of the elastic body roller. <P>SOLUTION: The inspection method for the surface state of the elastic roller includes a process for adjusting load so that penetrated amounts of an inspection roller in the axial direction of the elastic body roller are made equal to each other. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for inspecting the surface state of an elastic roller used in electrophotography and electrophotographic plate making systems such as copying machines, laser beam printers, and LED printers, and an inspection apparatus therefor.

  2. Description of the Related Art Conventionally, elastic rollers such as a charging roller, a developing roller, and a transfer roller have been used in electrophotographic apparatuses such as copying machines, laser beam printers, LED printers, and apparatuses of electrophotographic plate making systems. For example, as shown in FIG. 2, the elastic roller has a configuration having a shaft core body 2 and an elastic layer 11 covering the periphery of the shaft core body, and further covers the periphery of the elastic layer 11 as necessary. It has a form having a two-layer elastic roller body 13 having a surface layer 12 that is formed.

  The elastic roller applies a predetermined load to the shaft core 2 of the elastic roller main body 13 in order to bring the surface of the elastic roller main body 13 into close contact with an image carrier or a transfer material (paper). Rotate in the circumferential direction around the central axis of the shaft core 2 while being pressed against the body and the transfer material. In addition, in order to ensure a stable contact state with the image carrier, transfer material, etc., the elastic roller is made of a material such as rubber, elastomer or the like and formed into a solid or a foam having a fine cell diameter. The elastic layer 11 is composed of a hard elastic body. Further, the surface layer 12 is appropriately roughened by forming irregularities by incorporating particles or the like for the purpose of each elastic body roller such as preventing unevenness of image and deterioration of image quality or obtaining stable toner transportability. An elastic roller having the above is also known.

  Further, in these elastic rollers, the outer diameter shape is selected according to the purpose, such as a crown shape or a straight shape, in order to increase the adhesion to the image carrier or the like and to stabilize the paper transportability.

  In recent years, the electrophotographic apparatus has been increased in speed and definition, and in order to obtain a high-quality image, the conductive elastic roller is required to be a conductive uniform roller.

  On the other hand, the conductive elastic roller may not obtain a good image only by making the conductivity of the elastic roller main body uniform. For example, in the charging roller, if there is a dent that affects the image on the outer peripheral surface of the elastic roller body, a good image cannot be obtained at the dent. Or, depending on the size of the dent, residual toner, paper dust, etc. may be partly attached, which may cause image defects that reduce the uniform chargeability of the photoreceptor with long-term use (due to a decrease in conductivity). is there. Therefore, it is important to manage the surface state of the elastic roller that affects the image.

  In the conventional method for inspecting the surface state of the elastic roller, the elastic roller is brought into contact with the inspection roller, and the surface of the elastic roller is based on light leaked from the nip formed by the contact between the elastic roller and the inspection roller. The condition was being examined.

  Hereinafter, a conventional inspection method will be described.

In the inspection method of Patent Document 1, the conductive roller is brought into rolling contact with the inspection roller, light is irradiated to the nip portion (rolling portion) of the inspection roller and the conductive roller, and based on the light leakage from the nip portion, Whether or not the surface state of the conductive roller is acceptable is determined. In the inspection method of Patent Document 2, the charging roller is pressed against the inspection roller (metal roller) with a load of 40 to 42 g / cm. A laser beam is applied to the gap between the charging roller and the inspection roller, and the transmitted light detected by the sensor is used as a roller gap by an arithmetic unit, and the roller gap is used as an evaluation criterion for the charging roller.
JP 2003-149168 A JP-A-11-282230

  The above-described conventional inspection method of the surface state of the elastic roller will be described in detail with reference to a schematic cross-sectional view shown in FIG. FIG. 13 is a diagram illustrating a configuration for forming a nip, and is a cross-sectional view perpendicular to the rotation axis direction of the elastic roller and the inspection roller.

  1 is an elastic roller, 2 is a shaft core of the elastic roller 1, 3 is a recess in the surface of the main body of the elastic roller 1, and 4 is an inspection roller. 5 is a pressure contact force of the elastic roller 1 to the inspection roller 4, 6 is an amount of penetration of the elastic roller 1 into the inspection roller 3, 7 is a nip width, and 8 is inspection light. The cross sections of the elastic roller 1, the shaft core 2, and the inspection roller 4 are circular, and the axis of the inspection roller 3 is parallel to the shaft core 2 of the elastic roller. The elastic roller 1 is deformed at the contact portion between the elastic roller 1 and the inspection roller 4 by the pressing force 5 of the elastic roller 1 to the inspection roller 4 to form a nip having an intrusion amount 6 and a nip width 7. . Then, the formed nip is irradiated with light 8 to detect light leaked from the nip and inspect the surface state of the elastic roller.

  For example, in the inspection method described in Patent Document 1, the nip is formed by the weight of the elastic roller 1. Therefore, the pressure contact force 5 in the axial direction of the elastic roller becomes uniform, and the penetration amount 6 and the nip width 7 in the axial direction of the elastic roller 1 become uniform.

  However, since the above penetration amount depends on the weight of the elastic roller, when the light elastic roller is inspected, the penetration amount becomes small. If the intrusion amount is small, the rate of detecting small dents that do not affect the image increases, and there is a possibility that a roller that can be used as a non-defective product without any problem is judged as a defective product. In addition, since it is difficult to adjust the penetration amount 6 in the configuration described above, in an elastic roller having irregularities formed on the surface layer, leakage light from the nip may occur in addition to the dent that affects the image. there were.

  In the example of a configuration for forming a nip described in Patent Document 2, a pressure contact force 5 is applied to the elastic roller 1 by applying a load uniformly to both ends of the shaft core body 2 of the elastic roller 1 to cause the nip. Is formed. Further, the nip is formed by setting the total load load (the load applied to one end of the shaft core 2 × 2) by the total length of the main body of the elastic roller 1 to be 40 to 42 g / cm. Is disclosed.

  However, since the load is applied to both ends of the shaft core 2 of the elastic roller 1 in the above-described configuration, the pressure contact force becomes smaller toward the center of the roller due to the bending of the shaft core 2, and compared with both ends of the roller. As a result, the amount of intrusion at the center is reduced. Therefore, even if the depth of the same dent is the same, the dent at the center is detected, but the dent at the end is crushed and not detected.

  It is an object of the present invention to provide a method for inspecting the surface state of an elastic roller that accurately detects a dent without being influenced by the position of the dent while applying a load to both ends of the shaft core of the elastic roller. To do. It is another object of the present invention to provide a method for inspecting the surface state of an elastic roller capable of accurately detecting a dent affecting the image even in a configuration of an elastic roller having a surface layer that is appropriately roughened.

In order to achieve the above object, the invention according to the present application is
An elastic roller having at least a shaft core body and one or more elastic layers covering the shaft core body is brought into pressure contact with the inspection roller, and based on light leaked from the nip between the elastic body roller and the inspection roller, A method for inspecting the surface state of an elastic roller,
Leakage from the nip between the elastic roller and the inspection roller in a state where the elastic roller is pressed against the inspection roller by applying the load and the inspection roller is inserted into the elastic roller by a predetermined amount. Detecting light, and
This step is a method for inspecting the surface state of an elastic roller, including the step of adjusting the load so that the intrusion amount of the inspection roller becomes equal in the axial direction of the elastic roller.

The invention according to the present application is
The shaft core of the elastic roller having at least the shaft core and the elastic layer covering the shaft core is pressed against the outer peripheral surface of the elastic roller while keeping the shaft centers parallel to each other. An inspection roller that rotates synchronously with the elastic roller;
Drive means for synchronously rotating the elastic roller and the inspection roller;
A pressure cylinder that adjusts a load that abuts the elastic roller against the inspection roller while the elastic roller and the inspection roller rotate synchronously;
A light source disposed opposite to the nip between the elastic roller and the inspection roller, and a light receiver for detecting light;
The apparatus for inspecting the surface state of an elastic roller, comprising:

  In the method for inspecting the surface state of the elastic roller according to the present invention, the intrusion amount of the inspection roller in the axial direction of the elastic roller can be made constant by adjusting the load on the elastic roller. Therefore, even when inspecting an elastic roller whose surface layer is appropriately roughened, it is possible to prevent light leaking from the nip due to a dent other than the dent affecting the image. In addition, no matter where the dent is in the axial direction of the elastic roller, the intrusion amount is too small to detect a small dent that does not affect the image. Conversely, the indentation amount is too large to crush the dent that affects the image. Can prevent the situation. Therefore, it is possible to provide a highly accurate inspection method of the surface state of the elastic roller.

  According to the inspection method of the present invention, a load is applied to both ends of the shaft core of the elastic roller, the elastic roller is pressed against the inspection roller, and the inspection roller is inserted into the elastic roller by a predetermined amount. Then, the load is adjusted so that the intrusion amount of the inspection roller becomes equal in the axial direction of the elastic roller, and light leaking from the nip between the elastic roller and the inspection roller is detected.

  Hereinafter, the present invention will be described in detail with reference to a method for inspecting the surface state of a charging roller.

First, the measurement of the intrusion amount will be described with reference to FIG. FIG. 3 is an enlarged nip formed by the charging roller and the inspection roller, and is a partial cross-sectional view perpendicular to the rotation axis direction of the charging roller and the inspection roller. 101 is a charging roller which is an elastic roller, 4 is an inspection roller, 6 is the amount of penetration of the charging roller 101 into the inspection roller 4, 1 / 2W is 1/2 of the nip width, and R1 is The radius of the charging roller, R2 is the radius of the inspection roller, and 6 is the penetration amount of the inspection roller.
The penetration amount is converted from the nip width and the outer diameter of the charging roller and the inspection roller.

  A method for measuring the nip width will be described in order to obtain the penetration amount shown in the above formula.

  As an example of a method for measuring the nip width, as shown in FIG. 4, a DC power source is connected to the shaft core 2 and the image carrier (photosensitive member) 21 of the charging roller 101, and a predetermined voltage is applied to carry the image. A discharge mark caused by discoloration formed on the surface of the image carrier by causing discharge on the surface of the body is measured as a nip width.

  As another example of the measurement method, details will be described with reference to FIG. 5 which is a perspective view including a partially broken surface. 101 is a charging roller, 2 is a shaft core of the charging roller 101, and 31 is a cylindrical transparent drum made of glass or the like. Reference numeral 32 denotes a flange that supports the transparent drum from both ends, and reference numeral 33 denotes an enlargement optical system (video micro) such as a CCD camera that is located in the hollow portion of the transparent drum and can move in the axial direction of the charging roller 1. The axial centers of the charging roller 101 and the transparent drum 31 are arranged opposite to each other in parallel, and a single load F is uniformly applied to both ends of the shaft core 2 of the charging roller 101. Then, the nip portion between the charging roller 101 and the transparent drum 31 is photographed by the CCD camera 33, and then the image of the CCD camera 33 is enlarged to measure the nip width. Further, the entire nip width in the axial direction of the charging roller can be measured by moving the CCD camera 33 in the axial direction of the charging roller 101.

  It is preferable that a load is applied on the surface formed by the axial center of the charging roller 101 and the transparent drum 31 because the nip width can be accurately measured. The roundness of the transparent drum 31 is preferably 5 μm or less.

In this description, a cylindrical drum is used as the shape of the transparent drum, but a part of a cylindrical surface having a width equal to or larger than the nip width may be used as long as the above-described conditions are satisfied. The outer diameter of the transparent drum is preferably the same as the outer diameter of the inspection roller used in the inspection method of the present invention.
Each penetration amount at the axial position of the charging roller is calculated from the nip width obtained by the measurement described above, and the outer diameter or radius of the charging roller and the transparent drum.

  Next, the amount of each penetration at the axial position of the charging roller when the total load (that is, the weight obtained by doubling the single load) is sequentially increased to F1, F2, and F3 is shown. Examples are shown in FIG. 6 and FIG.

  In FIG. 6, the horizontal axis represents the position of the charging roller in the axial direction, the vertical axis represents the intrusion amount of the inspection roller, and the broken line represents a set intrusion amount line a that serves as a guide when adjusting the intrusion amount. The positions in the axial direction of the charging roller at the intersection of the set penetration amount line a and the penetration amount curve at the total load F1 are C and C2. The positions in the axial direction of the charging roller at the intersections of the set penetration amount line a and the penetration amount curve at the total load F2 are B and B2. The positions of the charging roller in the axial direction at the intersection of the set penetration amount line a and the penetration amount curve at the total load F3 are A and A2, and the central position in the axial direction of the charging roller is the center.

  The set intrusion amount for determining the set intrusion amount line a becomes a threshold value for the depth of the dent affecting the image in order to detect the dent affecting the image in the entire axial range of the charging roller without crushing. It is preferable to set to a different value. In FIG. 6, if it is the set penetration amount as described above, the preferable total load in C and C2 is set to F1. However, due to the bending of the shaft core, the axial penetration amount of the set constant load continuously decreases as it becomes the center. Therefore, in B, B2, A, and A2, the probability of detecting a small dent that does not affect the image increases.

  Therefore, the inspection range in the axial direction of the charging roller is divided, and the load is set so that the intrusion amount of the inspection roller becomes the set intrusion amount as described above for each inspection range. In this example, as shown in FIG. 1, the inspection range is divided into three ranges: A to A2 across the center, A to B and A2 to B2, and B to C and B2 to C2. To do. The total load is set to F3 when the inspection range is A to A2, the total load is set to F2 when A is B and A2 to B2, and the total load is set to F1 when B is C and B2 to C2. To do. That is, the load is adjusted so that the intrusion amount of the inspection roller becomes equal in the axial direction of the elastic roller. The intrusion amount when the total load is set is indicated by a thick line in FIG. 6 so that the intrusion amount of the inspection roller becomes an intrusion amount that can detect a dent affecting the image for each inspection range. As described above, by setting the inspection range, it is possible to detect a dent that affects the image without smashing it, and to make it difficult to detect a small dent that does not affect the image.

  The method of dividing the inspection range is arbitrary. For example, the effects of the present invention can be obtained even when the inspection is performed in two inspection ranges.

  FIG. 7 plots the total load and the penetration amount at each position in the axial direction of the charging roller shown in FIG. 6 and draws an auxiliary line at each plotted point. In FIG. 7, the horizontal axis represents the total load on the shaft core, the vertical axis represents the penetration amount of the inspection roller, and the broken line represents the set penetration amount line a.

  In the minute deformation range of interest here, the relationship between the total load and the amount of penetration is proportional at each position in the axial direction. Therefore, in the total load range in which the nip can be formed on the entire surface in the axial direction of the charging roller, the optimal total load for the set intrusion amount can be determined by measuring the intrusion amount in the axial direction with an arbitrary load at two points in advance. Can be requested.

  FIG. 6 is a diagram illustrating an example of detecting leakage light from the nip between the charging roller and the inspection roller by setting the load so that the inspection drum enters the set amount for each inspection range using the conditions described in FIG. It is shown in 1.

  101 is a charging roller, 2 is a shaft core of the charging roller, 3 is a recess on the surface of the main body of the charging roller, 4 is an inspection roller, and F is a shaft core 2 of the charging roller 101. One load is applied uniformly to both ends, 8 is inspection light, and 41 is a light receiver. Further, the axis of the inspection roller 4 is made parallel to the shaft core 2 of the charging roller 101. The inspection roller provided with the driving means is in pressure contact with the outer peripheral surface of the charging roller 101 while keeping the shaft centers parallel to the shaft core of the charging roller 101, and rotates synchronously with the charging roller 101.

  Reference numeral 41-1 indicates the first inspection range when the inspection range in the axial direction of the charging roller is set from B to C and from B2 to C2, and the light receiver 41 is indicated by hatching. Reference numeral 41-2 indicates the second inspection range when the inspection range in the axial direction of the charging roller is set from A to B and from A2 to B2, and the light receiving device 41 is indicated by hatching. Further, reference numeral 41-3 indicates the third inspection range indicated by diagonal lines on the light receiver 41 when the inspection range in the axial direction of the charging roller is set to A from the center and A2 from the center.

  The surface condition of the charging roller 101 is inspected as follows.

  First, the total load F1 is uniformly applied to both ends of the shaft core 2 of the charging roller 101, the charging roller 101 is pressed against the inspection roller 4, and the inspection roller is rotated while the inspection roller is inserted into the charging roller. The charging roller is driven to rotate as the roller rotates. The inspection light 8 from the light emitting device is continuously irradiated from one side to the entire axial surface of the nip formed by the charging roller and the inspection roller. A state in which the inspection light 8 irradiated in the first inspection range 41-1 leaks from the nip portion is detected by the CCD camera for the first time.

  Subsequently, the total load F2 is equally applied to both ends of the shaft core 2, and the second detection is performed in the second inspection range 41-2 in the same manner as the first detection. Further, the total load F3 is equally applied to both ends of the shaft core 2, and the third detection is performed in the third inspection range 41-3 in the same manner as the first detection, and the entire surface of the charging roller in the axial direction is detected. Inspect the surface condition.

  Based on the image information obtained by the three CCD cameras, it is determined that there is a dent that affects the image if there is light leaking from the nip between the charging roller and the inspection roller in the inspection range.

  In this way, the range of inspection in the axial direction of the charging roller is divided, and the charging roller is adjusted with high accuracy by adjusting the load for each inspection range so that the intrusion amount of the inspection roller becomes equal in the axial direction of the charging roller. Can be inspected.

  It is preferable to set the intrusion amount of the inspection roller so that a dent affecting the image can be detected without detecting a dent that does not affect the image. An example for obtaining such a set intrusion amount is shown below.

  For example, a charging roller having a dent on the roller outer peripheral surface is prepared by visual observation or the like, and a charging roller having a dent that affects the image is selected by using these to perform image printing by an electrophotographic apparatus. Then, the depth of the dents on the outer peripheral surface of the charging roller is measured with a known laser length measuring machine, laser microscope, roughness meter, etc., and the minimum value of the dent depth (that is, the depth of the dent affecting the image). Threshold value), and this value is set as the set penetration amount of the inspection roller. As a result, since the leakage light from the nip between the charging roller and the inspection roller is detected in a dent that is larger than the depth of the dent affecting the image, the dent affecting the image can be detected with high accuracy.

  In addition, a charging roller having a surface layer in which unevenness is formed by containing resin particles or the like has convex portions due to the resin particles distributed on the outer peripheral surface. In general, the elastic modulus of the convex portion of the surface layer is higher than that of the elastic layer. For this reason, it is preferable to set the intrusion amount of the inspection roller to be higher than the height of the convex portion in order to eliminate leakage light from the nip between the charging roller and the inspection roller due to the convex portion of the surface layer.

  If the relationship between the total load and the intrusion amount, the set intrusion amount, etc. is obtained for one charging roller, the charging roller created by the same manufacturing method is inspected without performing the above measurement. be able to.

  The roller type used in an image forming apparatus such as an electrophotographic apparatus or an electrophotographic plate making system has a straight outer diameter, or a non-roller whose outer diameter at the center of the elastic roller body is larger than the outer diameter at the end. Some have a straight cylindrical crown or taper shape. The elastic body roller having such a shape is suitably applied to the present inspection method.

  The outer diameter of the elastic roller is measured using a high-precision laser measuring machine LSM-430v manufactured by Mitutoyo Corporation. The crown amount is the difference in the outer diameter between the central portion in the axial direction of the elastic roller and the position 90 mm away from the central portion.

  The shaft core is not particularly limited as long as it is conductive and cylindrical, and any shaft core that can be used in the image forming apparatus can be used in the present invention. For example, stainless steel, iron, or a metal such as iron whose surface is nickel or nickel / chrome plated for rust prevention can be used as the shaft core.

  Polymer raw materials used for the elastic layer include acrylonitrile-butadiene rubber (NBR), ethylene-propylene-diene copolymer (EPDM), polybutadiene, natural rubber, polyisoprene, styrene-butadiene copolymer rubber (SBR), chloroprene ( CR), silicone rubber, epichlorohydrin rubber, urethane rubber and the like. These rubbers can also be used as a mixture, and are not particularly limited. In the conductive roller, the conductive material added to the polymer material includes conductive carbon black, a metal oxide such as TiO2, SnO2, and ZnO, a solid solution of SnO2 and Sb2O5, a solid solution of ZnO and Al2O3, and the like. Examples thereof include metal powders such as oxides and Cu / Ag, and are usually added in an amount of 5 to 200 parts by weight per 100 parts by weight of the polymer raw material. In addition to conductive particles, surfactants such as metal salts such as LiBF4 and NaSCN and quaternary ammonium salts can be used as the ion conductive material. Usually, 0.02 to 20 parts by weight is added to 100 parts by weight of the polymer material To do. Further, a filler, a reinforcing material, a plasticizer, a vulcanizing agent, a vulcanization accelerator, and the like are added to the polymer raw material as necessary.

  Surface Layer The elastic roller used in the present invention may have one or more surface layers. Moreover, the surface layer in which the unevenness | corrugation was formed with particle | grains contains a binder and a high molecular compound particle | grain, and is applied suitably for this inspection method.

  Examples of the binder include fluororesin, polyamide resin, acrylic resin, polyurethane resin, silicone resin, butyral resin, styrene-ethylene-butylene-olefin copolymer (SEBC), and olefin-ethylene-butylene-olefin copolymer (CEBC). ), Natural rubber and vulcanized rubber, ethylene-propylene-diene copolymer (EPDM), styrene-butadiene copolymer rubber (SBR), silicone rubber, urethane rubber, isoprene rubber (IR) ), Synthetic rubbers such as butyl rubber and acrylonitrile-butadiene copolymer rubber (NBR).

  The polymer compound particle is not particularly limited as long as it has an average particle diameter of 2.5 to 30 μm. Examples of the material of the polymer compound particles include silicon resin, fluororesin, (meth) acrylic resin, styrene resin, phenol resin, polyester resin, melamine resin, urethane resin, olefin resin, epoxy resin, and their co-polymers. Resins such as coalesced and modified products, derivatives, ethylene-propylene-diene copolymer (EPDM), styrene-butadiene copolymer rubber (SBR), silicone rubber, urethane rubber, isoprene rubber (IR), butyl rubber, acrylonitrile-butadiene A rubber such as a copolymer rubber (NBR) can be exemplified and is not particularly limited. The polymer compound particles are contained in an amount of 10 to 100 parts by weight with respect to 100 parts by weight of the binder.

  Moreover, many conductive particles are used to impart conductivity. Examples of the conductive particles include metal oxide conductive particles, metal conductive particles, conductive carbon black, and carbon conductive particles. As the conductive carbon black, furnace black, ketjen black, channel black and the like are preferably used. Furthermore, carbon black is preferably used as composite particles obtained by coating metal oxide particles with carbon black because of the controllability of the volume resistivity of the charging roller.

  The film thickness of the surface layer is appropriately adjusted to 5 to 50 μm. The film thickness of 5 to 50 μm can be obtained by cutting the produced elastic roller with a cutter knife or the like, observing the cross section of the layer with an optical microscope or an electron microscope, and measuring the thickness.

The roller hardness is preferably a micro hardness meter MD-1 type (manufactured by Kobunshi Keiki Co., Ltd.) and is applied to an elastic roller having a micro hardness of 40 to 80 degrees.
The surface layer is preferably applied to an elastic roller satisfying 10 μm ≦ Rzjis ≦ 20 μm as a ten-point average surface roughness (Rzjis) and 20 μm ≦ RSm ≦ 100 μm as a surface unevenness average interval (RSm). It is.

  Here, the ten-point average surface roughness and the surface unevenness average interval are measured values measured according to the standard of JISB0601 surface roughness. The measurement can be performed using a surface roughness measuring device SE-3400 manufactured by Kosaka Laboratory. Specifically, the 10-point average surface roughness is obtained by measuring the 10-point average surface roughness at 6 random points of the elastic roller with the measuring instrument and using the average value of the 6 points. Further, the surface unevenness average interval (RSm) is also specifically measured by the above measuring device at the 10-point unevenness average interval at 6 random points of the elastic roller, similarly to the 10-point average surface roughness (Rz). The average value of the six points is used.

  Further, as the material of the surface layer not containing particles, silicone-based, fluorine-based, urethane-based, acrylic-based, urethane-modified acrylic-based, and silicone-modified urethane-based materials are also used, and in particular, fluorinated alkyl groups and oxyalkylene groups are used. It is preferably used to contain polysiloxane having. In addition, the film thickness of the outermost layer is preferably a thin film in view of the electric characteristics or film thickness strength of the charging rubber roller, and there are layers having a thickness of 10 nm or more and less than 1000 nm. It is preferably applied.

  The elastic roller used in the present invention is used as a charging roller, a developing roller, a transfer roller, or the like in an image forming apparatus such as an LBP (Laser Beam Printer), a copying machine, or a facsimile machine. FIG. 8 shows an example of a schematic configuration of an electrophotographic apparatus provided with a process cartridge having a charging roller.

  In FIG. 8, reference numeral 201 denotes a cylindrical electrophotographic photosensitive member, which is driven to rotate at a predetermined peripheral speed around an axis 202 in the direction of an arrow. The electrophotographic photoreceptor 201 generally has a support and an inorganic photosensitive layer or an organic photosensitive layer formed on the support. Further, the electrophotographic photosensitive member 201 may have a charge injection layer as a surface layer.

  The surface of the rotationally driven electrophotographic photosensitive member 201 is uniformly charged to a predetermined positive or negative potential by the charging roller 101, and then output from exposure means (not shown) such as slit exposure or laser beam scanning exposure. Exposure light (image exposure light) 204 is received. In this way, electrostatic latent images corresponding to the target image are sequentially formed on the surface of the electrophotographic photosensitive member 201.

  When the surface of the electrophotographic photosensitive member 201 is charged by the charging roller 101, a voltage of only a DC voltage or a voltage obtained by superimposing an AC voltage on a DC voltage is applied to the charging roller 101 from a voltage applying unit (not shown). . In the examples described later, a voltage (−1050 V) of only DC voltage was applied to the charging roller 101. In the examples described later, the dark portion potential was set to -450V and the light portion potential was set to -100V.

  The electrostatic latent image formed on the surface of the electrophotographic photosensitive member 201 is developed (reversal development or normal development) with toner contained in the developer of the developing unit 205 to become a toner image. Next, the toner image formed and supported on the surface of the electrophotographic photosensitive member 201 is sequentially transferred onto a transfer material (such as paper) P by a transfer bias from a transfer unit (such as a transfer roller) 206. The transfer material P is taken out from a transfer material supply unit (not shown) between the electrophotographic photosensitive member 201 and the transfer unit 206 (contact portion) in synchronization with the rotation of the electrophotographic photosensitive member 201 and fed. .

  Examples of the developing unit 205 include a jumping developing unit, a contact developing unit, and a magnetic brush unit, but a contact developing unit is preferable from the viewpoint of improving toner scattering properties, and in the embodiments described later, a contact developing unit. It was adopted. Further, as a transfer roller serving as the transfer unit 206, a roller formed by covering a support with an elastic resin layer adjusted to a medium resistance is exemplified.

  The transfer material P which has received the transfer of the toner image is separated from the surface of the electrophotographic photosensitive member 201 and is introduced into the fixing unit 208 to be image-fixed to be printed out as an image formed product (print, copy). Is done. In the case of the double-sided image forming mode or the multiple image forming mode, the image formed product is introduced into a recirculation conveyance mechanism (not shown) and reintroduced into the transfer unit.

  The surface of the electrophotographic photosensitive member 201 after the transfer of the toner image is cleaned by receiving a developer (toner) remaining after the transfer by a cleaning means (cleaning blade or the like) 207. Further, after being subjected to charge removal processing by pre-exposure light (not shown) from a pre-exposure means (not shown), it is repeatedly used for image formation. When the charging unit (charging roller 101) is a contact charging unit, pre-exposure is not always necessary, and in the examples described later, the pre-exposure was performed.

  Among the above-described components such as the electrophotographic photosensitive member 201, the charging roller 101, the developing unit 205, the transfer unit 206, and the cleaning unit 207, a plurality of components may be housed in a container and integrally combined as a process cartridge. it can. The process cartridge may be configured to be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. In FIG. 8, the electrophotographic photosensitive member 201, the charging roller 101, the developing unit 205, the transfer unit 206, and the cleaning unit 207 are integrally supported to form a cartridge. The process cartridge 209 is detachable from the main body of the electrophotographic apparatus using guide means 210 such as a rail of the main body of the electrophotographic apparatus.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to these.

<Production of charging roller>
Epichlorohydrin rubber (trade name: Epichromer CG102, manufactured by Daiso Co., Ltd.) 100 parts by mass, raw material for elastic layer, calcium carbonate 25 parts by mass, MT carbon 2 parts by mass, zinc oxide 5 parts by mass, aliphatic polyester plasticizer 10 Parts by mass, 1 part by mass of stearic acid, 2 parts by mass of quaternary ammonium perchlorate and antioxidant (tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate methane ] 1 part by mass was kneaded uniformly with an open roll for 20 minutes. Further, 1 part by mass of a vulcanization accelerator (DM), 0.5 part by mass of a vulcanization accelerator (TS) and 0.5 part by mass of sulfur as a vulcanizing agent were added, and 15 parts by open roll. After kneading for a minute, sheeting was carried out to obtain a kneaded rubber material.

  On the conductive axial core body which apply | coated the adhesive agent, it extruded so that this kneaded rubber material might be coat | covered with the cross extrusion molding machine, and it shape | molded so that it might become a roller shape whose outer diameter is about 9.5 mm.

  Next, vulcanization and curing of the adhesive were performed using an electric oven at a temperature of 160 ° C. for 1 hour. After cutting off both ends of the rubber to make the rubber length 232 mm, the surface was polished so as to form a roller shape having an outer diameter of 8.5 mm to form an elastic layer on the conductive shaft core. At this time, the crown amount (difference in outer diameter at a position 90 mm away from the central portion and the central portion) was 130 μm.

  Subsequently, methyl isobutyl ketone was added to a caprolactone-modified acrylic polyol solution (trade name: Plaxel DC2016, manufactured by Daicel Chemical Industries, Ltd.) to adjust the solid content to 15% by mass.

With respect to 666.6 parts by mass of this solution, with respect to 100 parts by mass of the solid content of the acrylic polyol solution,
Composite particles 30 parts by mass Titanium oxide particles 20 parts by mass Acicular rutile type titanium oxide particles (average particle size 15 nm, length: width = 3: 1)
Modified dimethyl silicone oil 0.08 parts by mass Product name: SH28PA, manufactured by Toray Dow Corning Silicone Co., Ltd.)
7: 3 mixture of each butanone oxime block of hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI)
The mixed solution was adjusted by adding 80.14 parts by mass.

  The composite particles were produced as follows.

  To 7.0 kg of silica particles (average particle diameter 15 nm, volume resistivity 1.8 × 10 12 Ω · cm) as metal oxide-based particles, 140 g of methyl hydrogen polysiloxane was added while operating the edge runner. The mixture was stirred for 30 minutes with a linear load of 588 N / cm (60 Kg / cm). The stirring speed at this time was 22 rpm.

  Next, 7.0 kg of carbon black particles (particle diameter: 15 nm, volume resistivity: 2.0 × 10 2 Ω · cm) was added over 10 minutes while the edge runner was operated, and further 588 N / cm (60 Kg / cm). Mixing and stirring were performed for 60 minutes under a linear load. And after making carbon black adhere to methyl hydrogen polysiloxane coating | cover, it dried at 80 degreeC for 60 minute (s) using the dryer, and obtained composite particle. The stirring speed at this time was 22 rpm.

  The obtained composite particles had an average particle size of 15 nm and a volume resistivity of 1.2 × 10 2 Ω · cm.

  At this time, the mixture of HDI and IPDI was added so that “NCO / OH = 1.0”. About HDI and IPDI, HDI (trade name: Duranate TPA-B80E, manufactured by Asahi Kasei Kogyo), IPDI (trade name: Bestanat B1370, manufactured by Degussa Huls) were used.

  In a 450 mL glass bottle, 251.11 g of the above mixed solution and 200 g of glass beads having an average particle diameter of 0.8 mm as media were mixed and dispersed for 48 hours using a paint shaker disperser. After dispersion, 9 parts by mass of crosslinked polymethyl methacrylate (PMMA) particles (average particle size: 5.0 μm, volume resistivity: 1.0 × 10 15 Ω · cm), which are polymer compound particles (25 to 100 parts by weight of binder) (Equivalent part by weight) was added, followed by further dispersion for 1 hour to obtain a dispersion solution.

  This surface coating layer coating solution was dipped on the elastic layer once, air-dried at room temperature for 30 minutes or more, then dried in a hot air circulating dryer set at 80 ° C. for 1 hour, and further set at 160 ° C. It dried for 1 hour with the hot air circulation dryer, and formed the surface layer on the elastic layer. The dipping coating dipping time is 9 seconds, the dipping coating lifting speed is adjusted so that the initial speed is 20 mm / s, and the final speed is 2 mm / s. Between 20 mm / s and 2 mm / s is linear with respect to time. The speed was changed.

In this way, a plurality of charging rollers having an elastic layer and a surface layer on the conductive shaft core were produced.
The physical properties of the surface layer forming the irregularities with the prepared particles were extracted and measured by the measurement method described above.

  The average film thickness of the surface layer was 15.2 μm, the micro hardness was 61.3 degrees, the ten-point average surface roughness (Rzjis) was 6.7 μm, and the average surface roughness (RSm) was 63 μm. It was.

  The surface of all the manufactured charging rollers was measured by the measurement method described above.

  The average outer diameter of each central portion was Φ8.51, and the crown amount (difference in outer diameter at a position 90 mm away from the central portion) was 128 μm. The total number of currents measured was 1409 μA on average.

  In addition, the total number of manufactured charging rollers was visually inspected, and those having dents on the surface were selected.

<Inspection device>
9 and 10 are schematic views of an apparatus for inspecting the surface state of a charging roller which is an elastic roller of the present invention. FIG. 9 is a schematic front view, and FIG. 10 is a schematic diagram illustrating a light beam scanning unit.

  In FIG. 9, 1 is a charging roller for inspecting the surface state, 4 is an inspection roller that presses against the elastic body roller to form a nip, and 2 is at both ends to press the elastic body roller 1 against the inspection roller 4. It is an axial core body of the elastic roller 1 to which a load is applied. The inspection roller 4 has an outer diameter of Φ50 mm, a total length of 360 mm, a straightness of 2 μm, and a roundness of 4.5 μm. The axial parallelism of the charging roller and the inspection roller was adjusted to 0.02 mm or less.

  Reference numeral 51 denotes a bearing plate that supports both ends of the inspection roller 4 to be rotatable, and 52 denotes a motor that rotationally drives the inspection roller 4 through one of the bearing plates.

  53 is a stopper for positioning the end face of the shaft core 2 of the charging roller, and 54 is a stopper receiving plate for supporting the stopper. One of the stoppers 53 is fixed and the other is slidable, and the position of the stopper 53 is adjusted in the axial direction of the elastic roller.

  55 is a shaft core guide that receives the outer peripheral surface of the shaft core of the elastic roller 1 and keeps the shaft core of the elastic roller 1 and the axis of the inspection roller in parallel, and 56 is connected to the shaft core guide 55. A pressure cylinder for controlling the load, and 57 is an electromagnetic valve for switching the pressure of the pressure cylinder. The load can be changed in multiple stages.

  58 is an upper base for fixing the pressure cylinder 56, 59 is a guide for maintaining the accuracy of vertical movement of the upper base, and 60 is a vertical cylinder which is a driving force for moving the upper base up and down.

  Reference numeral 61 denotes a main body base for positioning and fixing the bearing plate 51, the motor 52, the stopper receiving plate 54, and the guide 58. In FIG. 10, 62 is a laser beam generated from a light source (not shown), 63 is a polygon mirror that scans the laser beam to the nip portion, and 64 is a leak from the nip between the charging roller and the inspection roller. It is a light receiver that detects light. A laser beam 62 is irradiated from a light source (not shown) so as to scan the nip portion via the polygon mirror 63, and the scanning light enters the light receiver 64 in a place where there is a depression.

<Example 1 and Comparative Examples 1 and 2>
(Evaluation sample)
Of the manufactured charging rollers, 126 had dents visible. Using the above-described electrophotographic apparatus of FIG. 8, 126 images with dents were drawn. Of these, 98 had black smears in their images. About 126 charging rollers with a dent, the depth of the dent and the position of the dent in the axial direction of the elastic roller were measured with a laser microscope. The following four samples were selected from 126 measured charging rollers.
Sample A: A charging roller having a 26.4 μm depth of 6 mm from the center and an image of black haze.
Sample B: a charging roller having a 27.0 μm dent depth at the end 110 mm from the center, resulting in a black-haze image.
Sample C: A charging roller having a recess depth of 15.6 μm 10 mm from the center and did not become a black haze image.
Sample D: A charging roller having a dent depth of 16.1 μm at an end portion of 107 mm from the center, and did not become a black haze image.

  The procedure for inspecting the charging roller with the inspection apparatus of the present invention will be described in an embodiment.

  From the above-mentioned measurement, since the depth of the dent was 25 μm or less did not become a black haze image, the set penetration amount was set to 25 μm.

  Next, by using the nip width measurement method of FIG. 5 described above, the outer diameter measurement of samples A to D is measured at a pitch of 2 mm in the axial direction, and the relationship between the total load and the penetration amount in the axial direction of the elastic roller is determined. Asked. This is shown in FIG.

  The inspection range is divided into two parts: the center (0) from the center (0) to the +90 mm position and the center (0) to the −90 mm position, the +90 mm position to the end (+114 mm), and the −90 mm position to the end (−114 mm). Divided. Then, the load was determined so that the set intrusion amount of the inspection roller becomes an intrusion amount that can detect the dent affecting the image for each inspection range as follows.

  In FIG. 11, the vertical line is lowered from the intersection of the load-penetration amount line at the end and the set penetration amount line b (arrow and broken line in FIG. 11). The intersection of the vertical line and the horizontal axis is the measured load in the inspection range from the +90 mm position to the end, and F = 940 g (F represents the total load). Next, the vertical line is lowered from the intersection of the load-intrusion amount line at the 90 mm position and the set intrusion amount line b (arrow and broken line in FIG. 11). The intersection of the vertical line and the horizontal axis is the measurement load in the inspection range from the +90 mm position to the center, and F = 1280 g.

Samples A, B, C, and D were inspected using the inspection apparatus of the present invention under the load conditions for each inspection range obtained as described above. As Comparative Example 1, Samples A and B were inspected under the condition that a total load of 1000 g was applied. Further, as Comparative Example 2, samples A, B, C, and D were inspected under the condition that a total load of 940 g was applied constant.
Table 1 shows the results of image evaluation and leakage light comparison. However, in the leakage light determination, “present” indicates defective product determination, and “not present” indicates non-defective product determination.

  In Comparative Example 1, the sample B having a dent at the end was subjected to a load exceeding the set penetration amount, so that the dent was crushed and was judged to be a good product despite being a defective product. In Comparative Example 2, the sample C having a minute dent that does not affect the image has been determined to be defective. On the other hand, in Example 1, samples A and B having a dent affecting the image were judged as defective, while samples C and D were judged as good and the dent inspection was performed with high accuracy.

<Example 2 and Comparative Example 3>
Next, as an example 2, an example in which the inspection area of the charging roller is divided into three will be described.

  As in Example 1, the nip width measurement method was used and the outer diameter of the charging roller was measured at a pitch of 4 mm in the axial direction to determine the relationship between the load in the axial direction of the elastic roller and the penetration amount, and the inspection range. The result of setting the measurement load at is shown in FIG. A 6-minute difference in the amount of penetration from the center to the edge at a load of 1000 g was used as a guide.

  The inspection range is from the center (0) to the +80 mm position and from the center (0) to the −80 mm position, the +80 mm position to the +108 mm position, the −80 mm position to the −108 mm position, the +108 mm position to the end portion, and the −108 mm position. It was divided into three at the end.

The method of determining the load so that the set penetration amount of the inspection roller for each inspection range becomes the penetration amount that can detect the dent affecting the image was also obtained in the same manner as in Example 1.
The measurement load in the inspection range from the +108 mm position to the end is F = 940 g, the measurement load in the inspection range from the +80 mm position to the +108 mm position is F = 1110 g, and the inspection from the center (0) to the +80 mm position. The measured load in the range was F = 1330 g.

(Evaluation sample)
The following samples were selected from 126 of which dents were visible.
Sample E: Black smear in image 98 Sample F: Sample in which dents are visible but no image problems 28 Samples E and F were inspected as Comparative Example 3 under the condition that a total load of 1000 g was constantly applied.
The determination comparison results are shown in Table 2.

  In Example 2, since the load was adjusted so that the set intrusion amount was such that the indentation could be detected, the indentation inspection was performed with high accuracy. In particular, 100% of the sample E having a dent affecting the image could be determined as a defective product. On the other hand, in Comparative Example 3, not all of the sample E could be correctly determined, and only 64% of the sample F could be correctly determined.

It is a figure explaining the structure which detects leak light for every division | segmentation test | inspection range which concerns on 1st Example of this invention. It is a figure explaining the structure of an elastic body roller. It is the figure which expanded the nip of a charging roller and an inspection roller. It is a figure explaining the measuring method of nip width. It is a figure explaining the measuring method of another nip width. It is a figure explaining the relationship between setting penetration | invasion amount and total load. It is a figure explaining the relationship between setting penetration | invasion amount and total load. It is a figure explaining schematic structure of the electrophotographic apparatus provided with the process cartridge. It is a figure explaining an inspection device. It is a figure explaining the light beam scanning part of a test | inspection apparatus. It is a figure explaining the relationship between the total load and the penetration | invasion amount in two test | inspection ranges. It is a figure explaining the relationship between the total load and penetration | invasion amount in three test | inspection ranges. It is a figure explaining the structure which forms the conventional nip.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Elastic body roller 2 Shaft core body 3 Recess 4 Inspection roller 6 Entry amount 7 Nip width 8 Leakage light 101 Charging roller F Load

Claims (3)

An elastic roller having at least a shaft core body and one or more elastic layers covering the shaft core body is brought into pressure contact with the inspection roller, and based on light leaked from the nip between the elastic body roller and the inspection roller, A method for inspecting the surface state of an elastic roller,
A load is applied to both ends of the shaft core of the elastic roller, the elastic roller is pressed against the inspection roller, and the elastic roller is inserted into the elastic roller by a predetermined amount. And a step of detecting light leaking from the nip with the inspection roller,
The step includes a step of adjusting the load so that the intrusion amount of the inspection roller becomes equal in the axial direction of the elastic roller, and a method for inspecting the surface state of the elastic roller.   The step of detecting leakage light from the nip between the elastic body roller and the inspection roller has a step of detecting the amount of intrusion when detecting leakage light for each of at least two inspection ranges in the axial direction of the elastic body roller. The method for inspecting the surface state of an elastic roller according to claim 1, further comprising a step of adjusting the load so as to be equal. The shaft core of the elastic roller having at least the shaft core and the elastic layer covering the shaft core is pressed against the outer peripheral surface of the elastic roller while keeping the shaft centers parallel to each other. An inspection roller that rotates synchronously with the elastic roller;
Drive means for synchronously rotating the elastic roller and the inspection roller;
A pressure cylinder that adjusts a load that abuts the elastic roller against the inspection roller while the elastic roller and the inspection roller rotate synchronously;
A light source disposed opposite to the nip between the elastic roller and the inspection roller, and a light receiver for detecting light;
An apparatus for inspecting the surface state of an elastic roller, comprising:

Images