JPH0324585A - Manufacture of roughened electrifying roller - Google Patents

Abstract

PURPOSE:To evenly rough on an electrifying roller by Bringing a belt-like abrasive into close contact with the surface of the electrifying roller by means of an elastic member. CONSTITUTION:The belt-like abrasive 12 for roughening the surface of a prime electrifying roller 11 is pressed on the electrifying roller by a spring and roughening is performed. The shafts of the electrifying roller 11 and the pressing roller 14 are drawn near each other by the spring which makes the press-contact force of a pressing roller 14 with the electrifying roller 11 average and prevents roughening uneveness, leakage, etc. Thus, since the belt-like abrasive 12 is pressed on the electrifying roller 11, pressure is kept constant and roughening is evenly accomplished.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] 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 a number of advantages, such as being able to be charged to an appropriate potential in the dark, having little charge dissipation in the dark, or being able to rapidly 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. They have the disadvantage that they cannot provide stable images over a long period of time because the sensitive dyes undergo charging deterioration 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. 425682 1, No. 4260
No. 672, No. 4268596, No. 4278747
No. 4293628, an electrophotographic photoreceptor using a disazo pigment exhibiting photoconductivity as a charge generation substance in a photosensitive layer functionally separated into a charge generation layer and a charge transport layer. It has been 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 shape of these direct charging members includes 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 are in direct contact, so there is a problem that the photoreceptor drum and the charging roller are likely to become sticky.
There was a problem in that charging was likely to be uneven.

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 photoreceptor 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 drum surface.

Further, when the surface of the charging roller is flat, toner adheres to the charging roller during repeated image formation, which tends to cause scumming 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 covey images with almost no background smearing 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 5.0 μm or more, but it is still difficult to accurately control the roughened state of the surface, which may cause uneven charging. It was ε1r｛leopard.

Therefore, the second object of the present invention is to uniformly roughen the surface of the charging roller, and the purpose is to [Means for Solving the Problems] The present invention will be explained 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, borivirol, and polythiophene, which are treated with conductive rubber by dispersing carbon, metal, etc. Artificial fibers or insulating materials such as polycarbonate, polyvinyl acetate, and polyester whose surfaces are coated with metal or other conductive materials can be used. The volume resistance value of these conductive members is 10' to 1Q11
Ω·CII1, optimally in the range 10'' to 1010 Ω'Cln.

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, 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 conventional surface roughening methods, it is difficult to uniformly roughen the surface of the charging roller, which causes a phenomenon in which it is difficult to uniformly charge the charging roller.

As a result of intensive studies on roughening the surface of a charging roller, the present inventors have developed a method for roughening the surface of a charging roller using a band-shaped abrasive material, in which the abrasive material is tightly attached to the charging roller using a spring. The maximum value, average value, and minimum value (in this specification, these are respectively referred to as the maximum surface Roughness, average surface roughness and minimum surface roughness) are all 0.3
〜5、A uniform rough surface condition within the range of θμ− can be obtained,
It has been found that uneven charging can be substantially prevented. That is, the present invention is a method for roughening the surface of a raw charging roller using a band-shaped abrasive material, which is characterized in that the surface is roughened by pressing the abrasive material against the charging roller with a spring.

When roughening the surface of a raw charging roller using a band-shaped abrasive material, the surface is roughened by pressing the abrasive material against the charging roller, but if the raw charging roller is eccentric, There is a drawback that the surface is not sufficiently roughened or unroughened because there are parts that do not come into contact with the abrasive material. However, by pressing the abrasive material against the charging roller, for example, by a spring, it is possible to keep the pressure of the abrasive material against the charging roller constant, and therefore the surface can be roughened with constant pressure. , is the essence of the present invention.

In carrying out the surface roughening method of the present invention, the apparatus schematically shown in cross section in FIG. 2 can be used as an example. Rotate the charging roller 11 clockwise or counterclockwise. On the other hand, the belt-shaped abrasive material 12 is fed out to the roller 1.
3, and is moved in the direction of arrow 16 toward a take-up roller 15 via a rubber pressing roller 14 that is in pressure contact with a charging roller. At this time, the band-shaped abrasive material 12 is pressed against the charging roller 11 by the spring l7 at the position of the pressing roller l4 so that the pressure on the charging roller 11 is kept constant, and therefore the charging roller l
The surface of 1 can be rubbed uniformly.

The band-shaped abrasive material used in the practice of the present invention includes those in which fine particles of aluminum oxide, silicon carbide, chromium oxide, diamond, etc. are coated and fixed on a film of polyester or the like.

The roughened charging roller according to the method of the present invention can be used not only for copying machines but also for laser printers, LED printers, CRTs, etc.
It can be used in electrophotographic applications such as printers and electrophotographic plate making systems.

[Example] The method of 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 FIG. 1 is a photoconductor for the copying machine, a roller and a paper feed guide, 6 is a transfer charger, 7 is a separation charger, 8 is a conveyance unit that sends the transfer paper to a fixing device (not shown), 9 is a cleaner, and 1O is a front The exposure light source 100 is a power supply device that applies voltage to the charging member 2.

Charging roller No. 2 was manufactured by the following method.

Chlorobrene rubber [Product name Denka Chlorobrene M-30
100 parts by weight of conductive carbon [manufactured by Denki Kagaku Kogyo ■]
5 parts by weight of the product (trade name: Conductex 900 manufactured by Columbian Chemical Company) were melt-kneaded, and a stainless steel shaft was inserted through the center to form a raw charging roller.

The maximum surface roughness, average surface roughness (R2), and minimum surface roughness on the surface are 0.3 μm, 0.2 μm, and O
．． It was Oum. This raw charging roller was installed in the apparatus shown in FIG. 2, and the surface was roughened.

In FIG. 2, reference numeral 11 is a plain charging roller, and a belt-shaped abrasive material 12 is in contact with the peripheral surface of the roller.

The abrasive material is fed out from the delivery roller 13, comes into contact with the charging roller 1l, is pressed against the surface of the roller 11 by the presser roller 14, and is sent to the take-up roller 15 while moving in the direction of arrow l6. A direction in which the spring 17 draws the axis of the charging roller 11 and the axis of the presser roller 14 toward each other as a means for equalizing the pressing force of the presser roller 14 on the charging roller l1 and preventing uneven surface roughening or leakage. is being pulled towards.

Abrasive particle size 15. When the surface was roughened using OtLm belt-shaped abrasive material (manufactured by Sumitomo 3M), the average surface roughness (R2) of the charging roller surface was 1. IILm, and the minimum surface roughness and maximum surface roughness were 0.6 μm and 1.5 μm, respectively, and a uniform rough surface could be obtained over the entire surface. Furthermore, when this roughened charging roller was installed in the above-mentioned modified copying machine and paper feeding durability was tested, no problems occurred up to 5,000 sheets. The charging exposure conditions are a DC voltage of -750V on the charging roller.
and AC peak-to-peak voltage of 15 (IOV) were superimposed, and the image exposure amount was 3.0 lux·sec and the pre-exposure amount was 10.0 lux·sec.

Comparative example l It was done in x seconds.

Comparative Example 1 The spring of the device used in Example 1 was removed and the same surface roughening treatment as in Example 1 was carried out.After the roughening was completed, the average surface roughness of the surface was measured and found to be 0.9 μm. Ta. Further, the minimum surface roughness was 0.0 μm and the maximum surface roughness was 1.5 μm. Furthermore, when the copying machine used in Example 1 was installed and subjected to paper passing durability, it was found that since the surface was unevenly roughened, image unevenness and stains on the white background area due to uneven charging occurred from the beginning of paper passing durability. After about 20 sheets have been used,
Horizontal streaks began to appear due to adhesion between the charging roller and the photoreceptor.

Examples 2 and 3 Abrasive grain size 1540 used in equipment similar to Example 1
The surface roughening treatment was performed using those shown in Table 1 instead of the μm band-shaped abrasive material. Table 1 also shows the average surface roughness, minimum surface roughness, and maximum surface roughness of the obtained surface, as well as the results of 5,000 sheet feeding durability when installed in the copying machine used in Example 1.

Table 1 As explained above, when forming fine irregularities on the surface of a band-shaped abrasive material, for example, springs are attached to both ends of the shaft of the rubber roller that presses the band-shaped abrasive material against the charging roller. By placing it in close contact with the charging roller, a uniform and stable rough surface can be obtained, and even when used in an electrophotographic device, there will be no unevenness of the image, background smearing, or sticking to the photoreceptor drum. Good images can be obtained.

The roughened charging roller according to the method of the present invention can be used not only as a primary charging member but also as a transfer charging member and a separation band.

[Effects of the Invention] When the roughened charging roller according to the method of the present invention is used, there is almost no adhesion between the charging roller and the photoreceptor drum, uneven charging, and scumming due to adhesion of toner to the charging roller, and stable repeated images can be obtained. I was able to get

[Brief explanation of drawings]

FIG. 1 is a structural diagram of a copying machine incorporating a surface roughening charging roller according to the method of the present invention, and FIG. 2 is a schematic structural diagram of an apparatus for carrying out the surface roughening method of the present invention. l...Photosensitive drum 2...Charging roller 3...Image exposure 4...Developing unit 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 O...Pre-exposure light source L...Charging roller 2...Band-shaped abrasive material 3...Feeding roller 4...Press roller 5...Take-up roller 7...Spring O... power supply

Claims (1)

[Claims] (1) In a method of manufacturing a roughened charging roller by roughening the surface of a charging roller using a band-shaped abrasive material, the abrasive material is brought into close contact with the surface of the charging roller by an elastic member. A method for manufacturing a roughened charging roller characterized by: