JPH0324584A - Manufacture of roughened electrifying roller - Google Patents

Abstract

PURPOSE:To evenly perform roughening an electrifying roller by selecting the grain size of an abrasive within a specific range and using a side with a bigger grain size for first step roughening and using a side with a smaller grain size for second step roughening. CONSTITUTION:Roughening the surface of a prime electrifying roller 11 is performed by making use of the belt-like abrasive 12. The abrasive whose grain size is 0.01-100mum is selected. The abrasive on the side with a rough grain size is used for the first step roughening and the abrasive on the side with a fine grain size is used for the second step roughening. Hereby, roughening is performed by interchanging the belt-like abrasive 12 or moving the electrifying roller 11 to another device. Thus, such an even roughening state as that the maximum, average and minimum values of the grain size are within the range of 0.3-5.0nun based on the measuring method of JIS is obtained in a short time and electrification uneveness if prevented.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a charging roller used in an electrophotographic apparatus. [Prior Art] Until now, as photoconductive materials used in electrophotographic photoreceptors,
Inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide are known. These photoconductive materials have many advantages, such as being able to be charged to an appropriate potential in the dark, having little charge dissipation in the dark, and being able to quickly dissipate charge when irradiated with light. On the other hand, it has various drawbacks. For example, in selenium-based photoreceptors, crystallization easily progresses due to factors such as temperature, humidity, dust, and pressure. Especially when the ambient temperature exceeds 40°C, crystallization becomes significant, resulting in decreased charging performance and white spots on images. There are drawbacks such as the occurrence of Cadmium sulfide photoreceptors do not provide stable sensitivity in humid environments, and zinc oxide photoreceptors require the sensitizing effect of sensitizing dyes such as rose bengal. It has the disadvantage that it cannot provide stable images over a long period of time because the sensitive dye deteriorates due to charging and photofading due to exposure light. On the other hand, it has been discovered that certain organic compounds exhibit photoconductivity. For example, organic photoconductive polymers such as boly-N-vinyl rubber, polyvinylanthracene, and low-molecular organic photoconductor phthalocyanine pigments such as carbazole, anthracene, birazolines, oxadiazoles, hydrazones, and polyarylalkanes. Organic pigments and dyes such as , azo pigments, cyanine dyes, polycyclic quinone pigments, berylene pigments, indigo dyes, thioindigo dyes, and methine squaric acid dyes are known. In particular, many proposals have been made for photoconductive organic pigments and dyes, which are easier to synthesize than inorganic materials, and the variety of compounds that exhibit photoconductivity in an appropriate wavelength range has been expanded. There is. For example, U.S. Patent Nos. 4,123,270, 4,251,613, and 42
No. 51614, No. 4256821, No. 42606
As disclosed in Japanese Patent No. 72, No. 4268596, No. 4278747, and No. 4293628, photoconductivity is used as a charge-generating substance in a photosensitive layer that is functionally separated into a charge-generating layer and a charge-transporting layer. Electrophotographic photoreceptors using disazo pigments are known. In the charging process in an electrophotographic process using such an electrophotographic photoreceptor, charging is conventionally carried out using corona generated by applying a high voltage (DC 5 to 8 kV) to a metal wire. However, with this method, ozone and NO. There have been problems such as corona products such as these altering the surface of the photoreceptor, leading to image blurring and deterioration, and wire stains affecting image quality, resulting in white spots and black streaks in the image. On the other hand, in terms of power, the current flowing to the photoreceptor is 5 to 30
%, and most of it flowed to the shield plate, making it inefficient as a charging means. In order to compensate for these drawbacks, many methods of direct charging have been researched and proposed (Japanese Patent Laid-Open No. 1782-1782).
67, 56-104351, 58-40566, 58-
139156, 58-150975, etc.). The shapes of these direct charging members include rollers, brushes (including magnetic brushes), blades, and belts, which can be selected according to the specifications and form of the electrophotographic apparatus. However, unlike corona charging, in the roller charging method, the charging member and the photoreceptor drum come into direct contact, so there is a problem that the photoreceptor drum and the charging roller tend to stick together.
There was a problem that uneven charging was likely to occur. In the direct charging method using a charging roller, when the distance between the photoreceptor drum and the charging roller becomes constant, discharge occurs and voltage is applied to the drum. Therefore, since the surface of the charging roller is flat, charging is often uneven due to the influence of unevenness or scratches on the surface of the photoreceptor drum. In addition, if the surface of the charging roller was flat, toner would adhere to the charging roller during repeated image formation, which would easily cause background smudges on the image. [Problems to be Solved by the Invention] A first object of the present invention is to provide an electrophotographic apparatus using a charging roller, in which stains on the white background of an image due to uneven charging and toner adhesion on the charging roller occur. An object of the present invention is to provide a charging roller for an electrophotographic device that can stably supply high-quality copy images without background smudges or the like. The above purpose is to ensure that the surface of the charging roller has a maximum surface roughness, an average surface roughness, and a minimum surface roughness of 0.3 according to the ten-point method.
The present inventor has already proposed that this can be achieved by providing unevenness with a size of .mu.m or more and 5.0 .mu.m or less. However, it is difficult to control the roughened state of the surface, and there is still room for improvement, which is presumed to be the cause of uneven charging. Therefore, a second object of the present invention is to uniformly roughen the surface of a charging roller, and the purpose is to first roughen the surface by using a band-shaped abrasive material with coarse abrasive grains to be used for surface roughening.
This can be achieved by then roughening the surface with fine particles. [Means for Solving the Problems] The present invention will be described in more detail below. Materials for the charging roller used in the present invention include metals such as aluminum, iron, and copper, and conductive polymer materials such as polyacetylene, bolivirol, and polythiophene, which are treated with conductive rubber by dissolving carbon, metal, etc. , artificial fibers, or materials in which the surface of an insulating material such as polycarbonate, polyvinyl acetate, or polyester is coated with metal or other conductive material can be used. The volume resistance value of these conductive members is lO0~1()lx
Ω・CII1, optimally 10”~1010Ω・CII1
The range is . If the charging roller and photoreceptor drum are used to produce an image when the surface of the charging roller is not roughened, the charging roller and photoreceptor drum tend to stick together, and there is also a high probability that toner will adhere to the charging roller. . Further, since the surface of the charging roller is flat, it is easy to pick up defects (unevenness and scratches) on the photoreceptor drum during discharge, and uneven charging is likely to occur. For the above reasons, it is necessary to roughen the surface of the charging roller in advance. Mechanical polishing is an excellent method for roughening the surface, and among these methods, a method using a band-shaped abrasive is more preferable.
The reason for this is that in the case of a sandblasting method or the like, the abrasive material is likely to be embedded in the charging roller, causing uneven charging, whereas in the case of a band-shaped abrasive material, this embedding is almost absent. However, with the conventional surface roughening methods, it is difficult to uniformly roughen the surface of the charging roller, and as a result, the phenomenon that uniform charging is difficult to perform during charging has not yet been resolved. The inventors of the present invention have conducted intensive studies on roughening the surface of the charging roller, and as a result, have arrived at the present invention as described below. That is, in a method of roughening the surface of a raw charging roller using a belt-shaped abrasive material, C. First, the surface is roughened in the first stage using an abrasive with a coarser grain size, and then the surface is roughened in a second stage with an abrasive with a finer grain size. R,), and its maximum value, average value, and minimum value (in this specification, these are referred to as maximum surface roughness, average surface roughness, and minimum surface roughness, respectively) are all 0. It has been found that a uniform rough surface condition within the range of .3 to 5.0 μm can be obtained in a short time, and uneven charging can be prevented. That is, the present invention provides a method for roughening the surface of a raw charging roller using a band-shaped abrasive material, in which the abrasive material has a particle size of 0.
01 = 100 μm is selected, and the first stage roughening is performed using an abrasive with a coarser grain size, and the second stage roughening is performed with an abrasive with a finer grain size. In the method of roughening the surface of the charging roller using a band-shaped abrasive, the surface of the charging roller is roughened uniformly by using a finer-grained abrasive, but the roughening takes a long time. In order to compensate for the disadvantages of both methods, which take time and roughen the surface using coarse-grained abrasives, the surface can be roughened in a short time, but the roughened state becomes uneven. The essence of the present invention is to roughen the surface using an abrasive with a coarser grain size, and then roughen it with an abrasive with a finer grain size to make the surface uniform. In implementing the method for manufacturing a surface-roughened charging roller of the present invention, an apparatus schematically shown in cross section in FIG. 2 can be used as an example. Rotate the elementary charging roller l1 clockwise or counterclockwise. On the other hand, the belt-shaped abrasive material 1
2 from the delivery roller 13, the abrasive material is directed toward the take-up roller 15 via the elastic pressing roller l4 that is in pressure contact with the charging roller.
Move in direction 6. At this time, the band-shaped abrasive material 12 rubs the surface of the raw charging roller 11 at the contact position of the presser roller l4. In the method of the present invention, this charging roller 1
1 is first roughened with a band-shaped abrasive material 12 having a coarser grain size, and then this abrasive material is replaced with a belt-like abrasive material 12 having a finer grain size to roughen the surface, or by polishing a belt-like material having a finer grain size. The charged roller is transferred to another device equipped with the material and the surface is roughened. The belt-shaped abrasive material used in the method of the present invention includes fine particles of aluminum oxide, silicon carbide, chromium oxide, diamond, etc., coated on a film of polyester, etc.
There is something fixed. The roughened charging roller of the present invention can be used not only in copying machines but also in laser printers, LED printers, CRT printers,
It can be used in electrophotographic application fields such as electrophotographic plate making systems. [Example] The present invention will be explained in detail below using specific examples. Example 1 A copying machine (NP-3525 manufactured by Canon) was modified as shown in Figure 1. 1 is a photoconductor for the copying machine, 2 is a charging roller that performs direct charging, 3 is an image exposure device, 4 is a developing device, 5 is a transfer paper feed roller and paper feed guide, 6 is a transfer charger, 7 8 is a separation charger, 8 is a conveyance unit that sends the transfer paper to a fixing device (not shown), 9 is a cleaner, 10 is a pre-exposure light source,
100 is a power supply device that applies voltage to the charging member 2.
Charging roller No. 2 was manufactured using the following method. chloroprene rubber

[Product name: Denka Chlorobrene M-30 manufactured by Denki Kagaku Kogyo ■] 100 parts by weight and 5 parts by weight of conductive carbon [Product name: Conductex 900 manufactured by Columbian Chemical Company] are melt-kneaded, and a stainless steel shaft is placed in the center of the resulting mass. It was formed into a charging roller. The average surface roughness (R2) of the charging roller surface is 0.2μ
m, and the minimum surface roughness and maximum surface roughness are 0 and O, respectively.
LLm and 0.3 μm. Using the apparatus shown in FIG. 2, this raw charging roller was roughened for 30 seconds with a band-shaped abrasive material having an abrasive particle size of 940 μm (manufactured by Sumitomo 3M, trade name: Wrapping Film #2000), and then roughened for 30 seconds with a band-like abrasive material having a particle size of 940 μm. The surface was roughened for 30 seconds using a 5 μm abrasive (manufactured by Sumitomo 3M, trade name: Wrapping Film #10000). The average surface roughness (R2) of this charging roller surface is 1
．． The minimum surface roughness and maximum surface roughness were 0.8 μm and 1.2 μm, respectively. When this roughened charging roller was installed in the above-mentioned modified copying machine and subjected to paper passing, no problems occurred up to 5,000 sheets. This is Example 1 and the results are shown in Table 1. In addition, the charging exposure conditions are a DC voltage of -750V on the charging roller.
By superimposing the AC peak-to-peak voltage of 1500 V, the image exposure amount is 3.
．． This was done with a pre-exposure of 0 lux/sec and a pre-exposure of 10 lux/sec. Example 2 A charging roller was prepared in the same manner as in Example 1, except that a roller protective layer was formed on the plain charging roller used in Example 1 using the following method. As the roller protective layer, methoxymethylated nylon [trade name Torezin EF30] is used.
T Teikoku Kagaku ■] 10 parts by weight and 90 parts by weight of methanol were dip coated onto the charging roller base layer, and after drying the film thickness was 10 parts by weight.
It was set to 0 μm. The average surface roughness (R2) of this charging roller surface is 0.2μ
With table, minimum surface roughness and maximum surface roughness are respectively Q. O
ItII1, 0.3μ faith.゛When the charging roller with a protective layer was used to roughen the surface in the same manner as in Example 1, the average surface roughness (Rl) of the surface of the roughened charging roller was
was 1.2 μm, and the minimum surface roughness and maximum surface roughness were 0.9 μm and 1.4 μm, respectively. When this roughened charging roller was subjected to paper feeding durability using the same equipment and conditions as in Example 1, no problems occurred up to 5,000 sheets. This is referred to as Example 2 and the results are shown in Table 1. Example 3 In Example 1, the plain charging roller was used with an abrasive particle size of l2.
The surface was roughened for 20 seconds with a 0 μm abrasive belt (manufactured by Sumitomo 3M, trade name: Wrapping Film #1200), and then a belt-shaped abrasive with an abrasive grain size of 0.3 μm (manufactured by Sumitomo 3M, trade name: Wrapping Film #). 15,000) for 40 seconds, but a charging roller was installed in the same apparatus and a similar experiment was conducted using charging exposure conditions, and no problems occurred until 5,000 sheets were passed. The average surface roughness of the surface of this roughened charging roller (
R. ) was 1.0 μm, and the minimum surface roughness and maximum surface roughness were O, 8 μm, and 1.2 μm, respectively. This is referred to as Example 3 and the results are shown in Table 1. Example 4 In Example 1, the plain charging roller was used with an abrasive particle size of 8.0.
The surface was roughened for 30 seconds with a band-shaped abrasive material having a particle size of 0.3 μm (manufactured by Fuji Photo Film Co., Ltd., trade name Wrapping Tape C-2000), and then a band-shaped abrasive material having an abrasive grain size of 0.3 μm (manufactured by Fuji Photo Film Co., Ltd., trade name Wrapping) was used. When a charging roller was installed in the same device except that the surface was roughened for 30 seconds using a table M-10000) and a similar experiment was conducted using charging exposure conditions, no problems occurred until 5,000 sheets were passed. There wasn't. The average surface roughness of the surface of this roughened charging roller (
R2) was 0.9 μm, and the minimum surface roughness and maximum surface roughness were 0.7 μm and 1.1 μm, respectively. This is referred to as Example 4 and the results are shown in Table 1. Comparative Example 1 A cumulative charging roller similar to that in Example 1 was made, and paper passing durability was carried out under the same equipment and conditions as in Example 1 without roughening. Horizontal streaks due to sticking with the body drum began to appear on the image. This was used as Comparative Example 1 and the results are shown in Table 1. Comparative Example 2 A raw charging roller similar to that in Example 2 was made, and paper passing durability was carried out using the same equipment and conditions as in Example 2 without roughening the surface. As a result, the charging roller and the photosensitive material were separated from about 10 sheets after passing. Horizontal streaks due to sticking with the body drum began to appear on the image. This was treated as Comparative Example 2 and the results are shown in Table 1. Comparative Examples 3 and 4 In Example 1, the plain charging roller was used with an abrasive particle size of 9.0.
A charging roller was installed in the same device, except that the surface was roughened using μm band-shaped abrasive material (manufactured by Sumitomo 3M Co., Ltd., trade name: Wrapping Film #20001 for 30 seconds and 60 seconds, respectively), and the same process was carried out under the same charging exposure conditions. An experiment was conducted.The average surface roughness (R
2) had a heel of 0.7 μm and 1.0 μm, respectively,
The minimum surface roughness and maximum surface roughness are 0.1 μm and 6, respectively.
．． They were 0 μm, 0.1 μm ugly, and 7.5 μm, and in all of them, image unevenness due to discharge unevenness and stains on the white background area occurred from the beginning of paper passing durability. These are referred to as Comparative Examples 3 and 4, and the results are shown in Table 1. Comparative Examples 5 and 6 In Example 1, the plain charging roller was used with abrasive grain sizes of 3 and 0.
A charging roller was installed in the same device, except that the surface was roughened with a μm band-shaped abrasive material (manufactured by Sumitomo 3M, trade name Wrapping Film #4000) for 30 seconds and 60 seconds, respectively, and under the same charging exposure conditions. conducted an experiment. The average surface roughness (R
z) were 0.3 μm and 0.8 μm, respectively,
The minimum surface roughness and maximum surface roughness are each 0. ltLm and 2.0 μm, and 0.1 μm and 4.0LLII1, and in both cases, horizontal streaks due to adhesion between the charging roller and the photoreceptor drum began to appear on the image after about 50 sheets were passed. These are referred to as Comparative Examples 5 and 6, and the results are shown in Table 1. Comparative Examples 7 and 8 In Example 1, the charging roller was
A charging roller was installed in the same device, except that the surface was roughened using a μm band-shaped abrasive material (manufactured by Fuji Photo Film Co., Ltd., trade name: Wrapping Table K-8000) for 30 seconds and 60 seconds, respectively, and under the same charging exposure conditions. A similar experiment was conducted. The average surface roughness (R
Z) are 0.1 μm and 0.2 μm, respectively, and the minimum surface roughness and maximum surface roughness are 0.0 μm and 0,0 μm, respectively.
3 μm, 0.0 ILm, and 0.6 μm, and in each case, horizontal streaks due to sticking between the charging roller and the photoreceptor drum began to appear on the image after about 20 sheets were passed. These are considered as Comparative Examples 7 and 8, and the results are shown in Table 1.
Shown below. Comparative Examples 9 and 10 In Example 1, the plain charging roller was used with an abrasive particle size of 0.5.
The surface was roughened for 30 seconds with a 9.0 μm abrasive strip (manufactured by Sumitomo 3M, trade name: Wrapping Film #10000), and then a belt-shaped abrasive with a grain size of 9.0 μm (manufactured by Sumitomo 3M, trade name: Wrapping Film). #2000) 3
The surface was roughened for 0 seconds. The average surface roughness (R2) of this charging roller surface is 0.7μ
m, but the minimum surface roughness and maximum surface roughness were each 0.
．． 1 .mu.m and 6.0 .mu.m, and image unevenness due to discharge unevenness and stains on the white background area occurred from the beginning of paper feeding durability. Further, after about 50 sheets, horizontal streaks due to adhesion between the charging roller and the photosensitive drum began to appear on the images. This was designated as Comparative Example 9, and the results are shown in Table 1. In addition, in Example 1, the plain charging roller was
．． The surface was roughened for 40 seconds with a 3 μm abrasive strip (manufactured by Sumitomo 3M, trade name: Wrapping Film #15000), and then a strip of abrasive with an abrasive grain size of 12.0 μm (manufactured by Sumitomo 3M, trade name: Wrapping Film #1200).
) for 20 seconds. The average surface roughness (R2) of this charging roller surface was 1.3 μm, but the minimum surface roughness and maximum surface roughness were 0.2 μm and 8.5 μm, respectively. Image unevenness and stains on the white background occurred due to unevenness. Further, from about 70 sheets onwards, horizontal streaks due to adhesion between the charging roller and the photoreceptor drum began to appear on the images. This was designated as Comparative Example 10, and the results are shown in Table 1. As mentioned above, as is clear from Table 1, two types of abrasives with significantly different particle sizes were used, and after the first roughening treatment was performed with a coarse abrasive, the second roughening treatment was performed with a fine abrasive. This process not only greatly reduces the time required for the surface roughening process compared to single roughening, but also eliminates most of the problems such as image unevenness, background smudges, and horizontal streaks caused by sticking to the photoreceptor drum. It is possible to obtain a good image without any problems. The roughened charging roller according to the present invention can be used not only as a primary charging member but also as a charging member for transfer charging, separation charging, etc. [Effects of the Invention] When the roughened charging roller according to the method of the present invention is used, there is substantially no adhesion between the charging roller and the photoreceptor drum, uneven charging, and background smearing due to adhesion of toner to the charging roller, resulting in stable performance. We were able to obtain repeated images.

[Brief explanation of drawings]

FIG. 1 is a structural diagram of a copying machine incorporating a roughened charging roller according to the method of the present invention, and FIG. 2 is a schematic diagram of an apparatus for carrying out the method of the present invention. 1... Photoreceptor drum 2... Charging roller 3... Image exposure 4... Developing device 5... Transfer paper feed roller and paper feed guide 6... Transfer charger 7... Separation charger 8... Conveyance section 9 that feeds the transfer paper to the fixing device (not shown)...
-Cleaner 10...Pre-exposure light source 11...Charging roller l2...Band-shaped abrasive material 13...Feeding roller l4...Press roller l5...Take-up roller 100...Power supply device

Claims (1)

[Claims] (1) In a method of roughening the surface of a charging roller by mechanical polishing using a belt-shaped abrasive, an abrasive with a particle size of 0.01 to 100 μm is selected as the abrasive used for roughening, and the first stage roughening is performed. Use an abrasive with a large grain size for
A method for producing a roughened charging roller, characterized in that, in the second stage of surface roughening, an abrasive with a smaller particle size is used.