JPH04143786A - Cleaning device - Google Patents

Abstract

PURPOSE:To eliminate the caking of contaminants on a photosensitive body and to prevent image deterioration by composing a cleaning tool of a cleaning tool A which removes the contaminants sticking on the surface of the photosensitive body and a cleaning tool B which polishes the photosensitive body surface uniformly. CONSTITUTION:The cleaning device 1 consists of the cleaning tool A and cleaning tool B. The cleaning tool A removes the contaminants such as corona products, which are considered to cause an image run, from the photosensitive body surface and is constituted by coating a roller type mandrel 2a with an elastic body and then forming active carbon fiber 3 and then a protection layer 4. The cleaning tool B, on the other hand, makes the photosensitive body surface uniform after the cleaning tool A removes the contaminants and is constituted by coating a mandrel 2b with an elastic body 5 and then forming a cleaning member 6 for removing sticking matter on the photosensitive body surface and polishes it. Consequently, the contaminants sticking on the surface of the photosensitive body are efficiently removed to clean the surface uniformly, thereby obtaining images of good quality for a long period.

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a cleaning device for an image forming apparatus such as an electrophotographic copying machine, a laser printer, or a facsimile machine, and particularly relates to a cleaning device for preventing image deletion. [Prior Art] In image forming devices such as electrophotographic copying machines, laser printers, and facsimile machines, amorphous silicon (
Inorganic photoconductive materials (Se photoreceptors) such as Se, AS2Se3, and SeTe, as well as organic photoconductive materials such as poly-N-vinylcarbazole, trinitrofluorenone, and various azo pigments. A photoreceptor using an OPC photoreceptor (OPC photoreceptor) or the like is generally known. For example, OPC photoreceptors have good electrical properties and spectral sensitivity, are inexpensive to manufacture, are non-polluting, and can be relatively easily processed into heald or drum-shaped photoreceptors, so they are widely used in both low-speed and medium-speed devices. It's being used. On the other hand, although the a-3i photoreceptor has a lower charging ability than other photoreceptors, it has high sensitivity and high abrasion resistance, so it is used in high-speed copying machines, laser printers, and the like. An example of an image forming apparatus using such a photoreceptor is shown in FIG. The photoreceptor 20 is a charging corona discharger (charging charger)
21 to be uniformly charged. There are two types of corona dischargers: the corotron type, in which a tungsten wire with a diameter of 40 to 100μ is stretched, and the scorotron type, in which a grid is further stretched near the opening of the corona discharger to equalize uneven discharge.
A high voltage of volts is applied. After an electrostatic latent image is formed by imagewise exposure in the exposure section 22, a toner image is formed in the developing device 23. The toner image is transferred using a corona discharger (transfer charger) 2.
4, the copy paper is separated from the photoreceptor by a separation corona discharger (separation charger) 25 and fixed by a fixing device 28 to become a hard copy. On the other hand, the toner image on the photoreceptor 20 after the transfer is cleaned by a cleaning device 26, and the series of copying steps is completed. By the way, in an image forming apparatus using a corona discharger, corona products, such as ozone and nitrogen oxides, are generated during corona discharge, and when these corona products adhere to the surface of the photoreceptor, the photoreceptor It is known that image quality characteristics deteriorate due to a decrease in the surface resistance of the surface layer or deterioration of the photosensitive characteristics of the photoreceptor. In particular, the surface resistance decreases in response to humidity, causing image blurring, and in the worst case, no image may be formed at all. Therefore, in order to maintain the initial image for a long period of time, it is necessary to eliminate the influence of corona products. In such image blurring, the degree of occurrence differs depending on the material that makes up the photoreceptor, and there are also differences in the causative agents that cause image blurring.
In both cases, corona products are the trigger for image blurring. The following are known as devices designed to prevent the deterioration of image characteristics caused by corona products as described above. As a first example, by improving the constituent materials of the photoreceptor itself,
Products that prevent a decrease in surface resistance are known. Specifically, photoreceptors include those in which a photosensitive layer is formed on a conductive support, and those in which a protective layer is further laminated on the photosensitive layer. When these photosensitive layers and protective layers are formed by spraying or coating methods, antioxidants (amines, hydroxylamines) are added or rubbed in from the outside to prevent the effects of corona products. I'm trying to exclude it. As a second example, it is known that corona dischargers are improved to suppress the generation of corona products and prevent corona products from adhering to the photoreceptor. The former is disclosed in, for example, JP-A No. 84-68774 and JP-A No. 4
It is described in JP-A No. 7-37547, JP-A-49-40739, JP-A-49-84660, etc. Au, Ag5PtSPd, Ni,
Fe. The charge wire, shield case, or grid is plated with a metal or metal oxide such as Ni 203, Bad, alumina, or chromium oxide to suppress the generation of corona products during corona discharge. On the other hand, the latter method is described, for example, in JP-A No. 63-311365, in which the inner wall and grid of the shield case are treated with activated carbon fiber, manganese oxide, or a metal chelate compound to absorb corona products. to prevent it from adhering to the photoreceptor. In addition, other measures have been taken, such as molding the grid with activated carbon fiber, attaching an absorbing member (for example, Japanese Patent Application Laid-open No. 1-210974), or creating a shield case shape that takes into account wind flow. There is also. Furthermore, there are shield cases that use PT or Ag plating in combination with an absorbent made of activated carbon, and these are described, for example, in JP-A-50-34828 and JP-A-52-133,894. ing. As a third example, it is known that the photoreceptor is heated with a heater or dried with hot air to eliminate the influence of humidity and prevent the surface resistance of the photoreceptor from decreasing. For example, JP-A No. 59-208558, No. 60-95467, No. 61-132977, No. 82-262065, etc. As a fourth example, it is known that corona products adhering to the surface of the photoreceptor are removed by polishing or wet cleaning. For polishing, use a roller or blade made of steel wire wrapped in a loop (for example,
1-1.61281), wet cleaning uses water or a solvent to remove corona products on the surface of the photosensitive layer. In addition to the above-mentioned four examples, for example, Japanese Patent Application Laid-Open No. 58-285
1111, JP 80-95459, JP 60-189769, JP 60-10265
Publication No. 9, JP-A-59-219770, JP-A-6
Those described in JP-A No. 0-134254, JP-A-60-17765, and JP-A-55-155369 are known. [Problems to be Solved by the Invention] In the image forming apparatus shown in FIG. 2, a corona discharger is used to perform charging, transfer, separation, etc., but ozone ( 03), nitrogen oxides (
Corona products such as NOx) are generated. As a result, these corona products are converted into hydrophilic compounds such as nitrogen compounds, aldehyde groups, and carboxyl groups due to discharge energy breakdown and the action of atmospheric moisture, carbon dioxide gas, nitrogen gas, etc., so that the surface of the photoreceptor becomes The electrical resistance (surface resistance) of the photoreceptor decreases due to oxidation, adsorption of compounds, and moisture absorption from atmospheric moisture, causing problems such as image blurring and even worse white spots due to image loss, which significantly deteriorates copy quality. . This phenomenon occurs in most photoreceptors to a greater or lesser degree, but it is particularly noticeable in photoreceptors using an a-5i layer, where SiO2 is deposited on the surface of the photoreceptor.
Due to the formation of second class hydrophilic substances, image blurring is likely to occur.
In addition to being highly durable, a-
It was found that a photoreceptor using C:H as a protective layer also had the same problems as the a-8i photoreceptor. In these photoreceptors, the higher the humidity, the more the image smearing may occur, and no image may be displayed at all. In e-charging laser printers, etc., the surface of the photoreceptor facing the negative corona discharger becomes contaminated due to corona products adhering to the corona discharger during the stoppage after copying, resulting in 30 to 40% of the photoreceptor surface being contaminated. Humidity also causes the phenomenon of missing white areas in the image. Also, when using AS2Se3 photoreceptor alone, image blurring is not a problem, but when using SnO2 or 5n02/5b203
It is also known that even when an organic resin such as ester or urethane cross-linked styrene-MMA resin in which ultrafine particles such as TiO2 are dispersed is overcoated, significant image blurring occurs. As described above, the process by which image deletion occurs differs depending on the configuration of the photoreceptor, but in all cases it occurs due to corona products. This phenomenon does not occur when the photoconductor used is new, but after repeated use in an image forming device, the surface of the photoconductor becomes contaminated and loses water repellency, and the surface of the photoconductor becomes extremely hard and scratches. This is thought to be due to the fact that hydrophilic substances remain forever. If these contaminants stick to the photoconductor, they cannot be removed by the cleaning blade of the toner cleaning device.
．． Even if the surface of the photoreceptor is rubbed with sandpaper of about 2000 to 4000 grit, the surface of the photoreceptor is only scratched and hardly improved. However, after studying various types of cleaning members, it was finally found that using activated carbon fiber as a cleaning member had a great effect, but it was found to be insufficient for fine image patterns. Therefore, the objects of the present invention are to (1) efficiently remove contaminants adhering to the surface of the photoreceptor that cause image quality deterioration, (2) uniformly clean the photoreceptor surface, and (3) maintain high quality over a long period of time. It is an object of the present invention to provide a cleaning device capable of maintaining a clean image. [Means for Solving the Problems] The present invention provides a cleaning tool A mainly composed of activated carbon fibers for removing contaminants attached to the surface of a photoreceptor between a toner cleaning device and a charging charger, and a photoreceptor. This is achieved by equipping a cleaning device equipped with a cleaning tool B that polishes the surface uniformly. Hereinafter, the present invention will be explained according to the drawings. FIG. 1 is a partial schematic diagram of an image forming apparatus equipped with a cleaning device of the present invention. 20 is a photoreceptor, the photoreceptor is OPC
A photoreceptor, a-8i bad photoreceptor, selenium photoreceptor, etc., and a-C:H layer, a-5iN:H, a-5
The protective layer may be an amorphous silicon-based thin film such as iC:H, or an organic thin film layer in which a resistance control agent or the like is dispersed. 21 is a scorotron type charging corona discharger having a grid. For example, when using an OPC photoreceptor for θ charging, it is necessary to use a θ charging system or a corona discharger or e
In the case of discharge, a large amount of corona products that cause image deletion are generated, increasing the degree of contamination of the photoreceptor. Reference numeral 22 denotes an exposure section, where in a laser printer an image is produced by an LED with a wavelength of 750 to 820 nm, and in an analog image forming device or some digital electrophotographic copying machines, an original image projected by a halogen lamp or fluorescent lamp is passed through a lens. , is irradiated onto the photoreceptor. 26 is a device for cleaning the toner image after image transfer. Reference numeral 1 denotes a cleaning device for cleaning corona products adhering to the photoreceptor after toner image cleaning. The cleaning device 1 is composed of a cleaning tool A and a cleaning tool B. Cleaning tool A is a cleaning tool for removing contaminants such as corona products that are considered to be the cause of image blurring from the surface of the photoreceptor. It consists of an elastic body coated with activated carbon fibers 3 and a protective layer 4 coated thereon. However, if the activated carbon fiber 4 alone has sufficient wear resistance, the protective layer 4 is not necessary. Activated carbon fibers are manufactured using cellulose-based polyacrylonitrile-based (PAN-based) fibers, phenolic resin, pitch, etc., but polyacrylonitrile-based fibers are used to absorb and decompose corona products such as ozone and NOx. The activated carbon fiber is smudged. This effect is also effective against corona products adhering to the surface of the photoreceptor, and when used as a cleaning member, the adhering material can be removed well and the removed material is adsorbed, so it is preferable as a cleaning member. The activated carbon fiber 3 used in the present invention has a fiber diameter of 5 to 30μ.

The shape is felt, woven, mat, etc., and the thickness is about 0.5 to 3 mm. However, if these materials are used alone, their durability is currently insufficient and the fibers will break and wear out, so the surface in contact with the photoreceptor should be covered with a protective layer.
It needs to be covered with. This coating layer is not preferable because it inhibits the effects of the activated carbon fibers. Therefore, the protective layer 4 has a certain degree of roughness. It is preferable to use a wear-resistant material that does not damage the photoreceptor and has a film thickness of about 5 to 200 μm. In the present invention, the polyester fiber used is a nonwoven fabric with a thickness of about 50 to 100 microns processed like transparent Japanese paper, but there is no particular limitation as long as it has durability similar to or greater than this. By the way, in the cleaning tool A, activated carbon fibers 3 with a thickness of 0.5 to 2 fflIIl are wrapped in 1 to 5 layers on a core bar 2a, and 1 to 3 layers of transparent Japanese paper-like nonwoven fabric of about 50 to 100 μm are wrapped around the core bar 2a.
Use a heavily rolled one. Even if the cleaning tool A is not rotated, and the part that contacts the photoreceptor is shifted every certain number of sheets, or even if it is rotated in the same direction as the photoreceptor, the effect is almost the same. On the other hand, cleaning tool B is a cleaning tool for making the surface of the photoreceptor uniform after removing contaminants with cleaning tool A. Although cleaning tool A can remove contaminants to a level that poses no problem for practical use, it is impossible to make the entire surface uniform, and the reproducibility of fine image patterns such as one-dot patterns and lines of 100 to 500 μm is difficult to achieve. Some parts are missing, 8
At high humidity levels of about 5 to 90%, signs of image blurring may occur. This means that some contaminants that have not been removed still remain on the photoreceptor 2o. The cleaning tool B covers a core metal 2b with an elastic body 5 such as rubber, foam material, or elastic plastic having a JIS hardness of 50 to 80 degrees, and further removes deposits on the surface of the photoreceptor. A cleaning member 6 for polishing is coated. The cleaning member 6 must be of a uniform quality that does not scratch the photoreceptor, has wear resistance, and does not cause clogging due to dust. This cleaning material is a cloth product made of ultra-fine fibers of about 2 to 10 μm, and is known under product names such as Hi-Lake (Otaku), Sophrina (Kuraray), Bellseim (Kanebo), Ecsaine, and Tracy (Toshi). Although there are many, nonwoven fabrics such as Ecsaine, Tracy, and Amara are particularly suitable. These non-woven cleaning materials ■do not shrink or become hard even when wet with water, ■do not tangle, ■can be washed, ■do not get moldy,■
No odor ■The material is polyester, etc., but the fiber diameter is small and has elasticity, so it does not get scratched.
It has the following characteristics: 1) It has a tight texture and clean wiping marks, 2) It has high tensile strength, and 2) It does not use glue, making it an excellent cleaning material for photoreceptor polishing. This cleaning member is wrapped around the elastic body in layers of about 1 to 1.0 weight, but the number of layers is changed depending on the thickness of the nonwoven fabric. Usually, about 2 to 4 layers is sufficient. It is desirable that both of these cleaning tools be in constant contact with the photoreceptor when the image forming apparatus is in operation. An aluminum support having a diameter of 80 ID II and a length of 350 I was sequentially coated with a subbing layer made of T]02 and a polyamide resin, a charge generation layer (0.2 μm) made of a trisazo pigment and a polyvinyl butyralamide resin, and a charge generation layer (0.2 μm) made of hydrazino and a polycarbonate resin. charge transfer layer (25μlI+)
Laminate. A Knoop hardness of 950 to 120 is obtained by using C2H4 gas as a raw material on the OPC photoreceptor constructed in this way.
An amorphous carbon film of 0 kg/mm2 and a film thickness of 7000λ is laminated by plasma CVD method, and an LED with a wavelength of 780Im is produced.
It is installed in an experimental racer beam printer (electrostatic negative) that uses the light source as a light source. Cleaning tool A of the cleaning device was made by pasting a 2 mm thick rubber sheet onto an aluminum shaft with a diameter of 5 mm, and then covering the rubber sheet with a heat shrink tube. Felt-like activated carbon fiber with a thickness of 1.0 to 1.5 tnm (Fine Guard Felt; manufactured by Toho Rayon) as activated carbon fiber
and polyester fiber-based Japanese paper transparent non-woven fabric with a thickness of approximately 100 μm were wrapped three times, and the surface in contact with the photoreceptor was wrapped with double layers of non-woven fabric, and the edges were treated. . On the other hand, cleaning tool B has a 1mm thick rubber sheet pasted on an aluminum shaft with a diameter of 15mm and an additional 0.5mm thick rubber sheet.
A 7 mm thick non-woven fabric (Ecsaine; manufactured by Toshi) was wound three times to produce a sample. Both cleaning tools A and B are rotated in the same direction as the photoconductor, and the rotation speed of cleaning tool A is approximately 307 pm, and that of cleaning tool B is 11 pm.
It was set to 0 γpm. The implementation method is: ■Cleaning tools A and B work together; ■Cleaning tool A only works; and ■Cleaning device is not set. 140,000 copies were made at a rate of 3,500 copies per day at 22°C and 80% RH. After completing the check in a high humidity environment, after controlling the humidity for 5 hours at 22°C and 55% RH, 1 × 1 dot pattern, 2 × 2 dot pattern, 20
The image quality was checked focusing on the reproducibility of the 0 μm line. The results are shown in the table. O: No problem, approximation to the initial image △: Reproducibility deteriorates mainly in thin lines Line images of 0.2a or more have no problem
When only the cleaning i4A was operated, 10,500 sheets were printed, and when checking, it was confirmed that a 1×1 dot pattern and a 200 μl line disappeared, but other patterns showed almost normal image quality. However, when both cleaning tools were operated, the image quality was close to that of the initial image even after 14,000 sheets, confirming the effectiveness of the cleaning tools.

[Brief explanation of the drawing]

FIG. 1 is a partial schematic diagram of the present invention, and FIG. 2 is a schematic diagram showing an example of an image forming apparatus. ■... Cleaning device, 2a, 2b... Core bar, 3... Activated carbon fiber, 4... Protective member,
5... Elastic body 6... Cleaning member, 20
...Photoreceptor, 21...Charging charger, 22...Exposure section, 23...Developing device,
24... Transfer charger, 25... Separation charger, 26... Toner cleaning device,

Claims (3)

[Claims] (1) In a cleaning device used in an image forming apparatus and installed so as to come into contact with a photoreceptor, the cleaning tool A is used to remove contaminants attached to the surface of the photoreceptor.
and a cleaning tool B for uniformly polishing the surface of the photoreceptor. (2) The cleaning device according to claim (1), wherein the cleaning tool A is mainly composed of activated carbon fiber. (3) The cleaning device according to claim (1), wherein the surface of the cleaning tool B that comes into contact with the photoreceptor is made of a nonwoven fabric made of at least ultrafine fibers.