JP5494945B2 - Image forming apparatus - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus employing an electrophotographic process such as a copying machine, a printer, a facsimile, or a complex machine thereof, and more particularly to an image forming apparatus in which a cleaning blade is disposed in contact with an image carrier. Is.

  In an image forming apparatus using an image forming process, an electrostatic latent image is formed on an image carrier charged by a charging unit (hereinafter also referred to as a photoreceptor) by a latent image forming unit such as optical writing or document image exposure. After the electrostatic latent image is formed and developed with the developer of the developing means to make a visible image, the visible image is transferred to a recording material such as recording paper by the transferring means, and transferred to the recording material. The visual image is fixed by a fixing unit to form an image.

  In such an electrophotographic image forming apparatus, generally, a toner image is transferred from an image carrier (hereinafter also referred to as a photoreceptor), and unnecessary toner remaining on the surface of the image carrier is removed by a cleaning device. To do. As this cleaning device, since it has a simple structure and excellent cleaning performance, a blade-type device that is scraped off by a cleaning blade is widely used. The blade system has a simple configuration and excellent cleaning performance.

  The cleaning device has a counter method in which the cleaning blade is pressed in the reverse rotation direction (counter) with respect to the rotation direction of the photosensitive member, or a reading method in which the cleaning blade is pressed in the forward rotation direction (leading). If necessary, a cleaning brush such as polyester fiber or nylon fiber is used in combination. When the blade is installed in the counter direction with respect to the rotation direction of the photoconductor, the biting into the photoconductor is increased, and the toner cleaning performance can be improved.

Since the cleaning blade is strong in mechanically rubbing the surface of the image carrier, image flow (image blur) hardly occurs. However, it is a major problem to prevent wear and scratches on the surface of the image carrier. In addition, there are problems such as damages such as wear and chipping caused by repeated use of the edge portion of the blade, and generation of abnormal noise and turning of the blade due to friction with the image carrier.
In order to prevent these problems, a method of applying or supplying a lubricant to the blade surface is widely used.

For example, a method has been proposed in which a certain amount of toner is supplied to a blade without using additional means such as a lubricant, and the blade is turned over and edge wear is prevented by using a lubricant contained in the toner (for example, Patent Document 1). 2). However, in this method, the toner may function as an abrasive for the blade, and there is a problem that the wear of the blade is promoted.
In addition, a method for preventing the initial turning of the blade by applying a lubricant to the blade edge portion in advance has been proposed (for example, see Patent Documents 3, 4, and 5). However, this method is good in the initial stage, but there is a problem that the lubricating action is interrupted unless replenishment is performed during long-term use.
Further, an image forming method has been proposed in which oil is applied to the blade edge portion in advance and a solid lubricant is applied to the image carrier (see, for example, Patent Document 6). Further, a method for supplying a lubricant to a blade by a member holding the lubricant has been proposed (see, for example, Patent Documents 7 and 8). However, these methods are good over time, but the number of members increases, so there are problems with cost and downsizing of the apparatus.
Many methods for providing a lubricant layer on a blade have been proposed (see, for example, Patent Documents 9 and 10). However, these methods have a problem of shortening the blade life due to, for example, peeling of the lubricating layer after long-term use. Further, depending on the type of lubricant particles and the state of adhesion and dispersion, the image carrier may be damaged by long-term use.

  The object of the present invention is to ensure sufficient cleaning performance, without damaging the abutting image carrier even after long-term use without increasing the number of parts, preventing blade turning and abnormal noise, and extending the life of the blade An image forming apparatus capable of achieving the above is provided.

As described above, the contact resistance between the surface of the cleaning blade in contact with the image carrier and the surface of the image carrier is extremely large. When the image carrier rotates, abnormal noise such as blade squealing occurs, and further blade turning occurs. There is. In order to solve this problem, a lubricant that improves rotation is required. Further, it is optimal that the lubricant is always in a small amount at the contact portion between the blade and the image carrier, and if it is too much, an abnormal image is generated.
As a result of various studies, the present inventors have included a specific liquid lubricant in the cleaning blade and gradually exude the lubricant to the blade surface, so that the blade and the image carrier are always in contact with each other. We thought that the optimal condition with a small amount of lubricant could be realized. This is because the lubricant carried in the cleaning blade oozes out when the image carrier abutting on the cleaning blade is reversed in the direction opposite to the rotation direction (forward rotation) at the time of image formation. It was confirmed that this was done by lowering the contact resistance of the image carrier. The present invention has been made based on these findings.

The object of the present invention is then achieved by technical means.
(1) An image forming apparatus having a photoconductor rotated in a predetermined direction and a cleaning device for removing toner powder on the photoconductor by at least one blade disposed in contact with the photoconductor. The blade is made of polyurethane and contains a lubricant, and the lubricant is any one of a fluorinated oil selected from fluoropolyether and hydrofluoroether, and the photoconductor has the predetermined at a predetermined timing. It is characterized by being driven to rotate in the opposite direction to the direction.
( 2 ) The image forming apparatus according to (1) , wherein the fluorine-based oil is mixed in a bulk composition ratio of 1.0 to 20% by weight.
( 3 ) The image forming apparatus described in (1) or (2) is characterized in that the reverse rotation driving of the image carrier is performed at the end of one image forming operation.
( 4 ) In the image forming apparatus according to (1) or (2), the image carrier is rotated in the reverse direction before the image forming operation (when the power is turned on).
( 5 ) In the image forming apparatus according to any one of (1 ) to (4), a distance for rotationally driving the image carrier in the reverse direction is 1 mm or more.
( 6 ) In the image forming apparatus according to any one of (1) to (5), a distance for rotationally driving the image carrier in the reverse direction is 1 to 10 mm.

  According to the present invention, since the image carrier is driven in the reverse direction at a predetermined timing, even when a large amount of toner stays at the edge of the cleaning blade containing the lubricant, the image carrier. It is possible to provide an image forming apparatus in which the lubricant is stably supplied on the top and the deterioration of the cleaning blade and the image carrier, the poor cleaning, and the occurrence of filming are reliably reduced.

1 is an example of an image forming apparatus including a cleaning device of the present invention. FIG. 5 is a diagram showing the shape of the cleaning blade 30 arranged in the counter direction when the image carrier 1 that rotates clockwise in the clockwise direction (direction of arrow A) during image formation is rotating forward. FIG. 3 is a view showing the shape of the cleaning blade 30 when the image carrier 1 that rotates clockwise in the clockwise direction during image formation is reversed in the arrow B direction.

  The image forming apparatus of the present invention includes a photosensitive member and a cleaning device having a blade disposed in contact with the photosensitive member. More specifically, at least the photosensitive member, the charging device, and the image exposure device. In an image forming apparatus comprising an apparatus, a developing device, a transfer device, a fixing device, and a cleaning device, the photosensitive member can be reversed in the direction opposite to the rotation direction (forward rotation) at the time of image formation. In which the blade contains a lubricant.

  As an image forming apparatus provided with a cleaning blade, for example, an image forming apparatus having a configuration as shown in FIG. 1 is known. The image forming apparatus 20 includes a photoreceptor 1, a charging device 2, an image exposure unit 3, a developing device 4, a transfer device 5, a cleaning device 6, a fixing device 8, and the like. The photoreceptor 1 is rotated in the direction shown in the figure, and the surface of the photoreceptor 1 is uniformly and uniformly charged by the charging device 2, and the photoreceptor 1 is exposed by image exposure from the image exposure unit 3. An electrostatic image is formed thereon.

  The electrostatic latent image on the photoreceptor 1 is developed with a developer (toner) supplied from the developing device 4 to form a visible image. The developing device 4 includes a developing roll and a toner layer thickness regulating member, and supplies the stored toner to the photoreceptor 1. The toner image on the surface of the photoreceptor 1 is transferred onto a predetermined transfer material by the transfer device 5 and sent to the fixing device 8.

  The photoreceptor 1 is an image carrier for carrying an electrostatic latent image and a toner image. The toner image on the photoreceptor 1 is transferred to a transfer material by the transfer device 5, but a part of the toner image may remain untransferred. Therefore, the untransferred toner on the photoreceptor 1 is removed by the cleaning device 6.

The cleaning device 6 includes a cleaning blade 30 and a predetermined support member, and is disposed around the photoreceptor 1. The cleaning blade 30 of the present invention is in contact with the surface of the photoconductor 1 in a counter direction with respect to the rotation direction (positive rotation) of the photoconductor 1 during operation (image formation).
Then, when image formation is performed by the image forming apparatus, the tip of the cleaning blade 30 is pressed against the photoreceptor 1 in the counter direction so as to come into sliding contact, and scrapes off toner adhering to the surface of the photoreceptor 1. . The toner scraped off is taken out through a toner collecting coil (not shown).

  FIG. 2 schematically shows the shape of the blade 30 when the photosensitive member 1 rotating in the clockwise direction during image formation is rotating in the forward direction. In the drawing, an arrow A indicates the rotation direction (forward rotation) of the photosensitive member 1. In general, it has been confirmed that the portion of the blade 30 that is in contact with the photosensitive member 1 when the photosensitive member 1 is rotated forwardly swings in a range of approximately 10 μm to 30 μm due to stick slip. However, the amount of expansion / contraction is small at this amplitude, and the lubricant contained in the blade 30 does not sufficiently ooze out.

  FIG. 3 schematically shows the shape of the tip of the blade 30 when the photoreceptor 1 that rotates clockwise in the clockwise direction is reversed (reversely rotated) in the direction of arrow B. After the blade 30 has the shape shown in FIG. 3, the photosensitive member 1 is rotated forward again to the state shown in FIG. 2 (the blade 30 is in the counter direction with respect to the rotational direction (forward rotation) of the photosensitive member 1). Like). By repeating the forward rotation and the reverse rotation of the photoreceptor 1 in this manner, the entire blade 30 can be expanded and contracted, and the lubricant in the entire blade 30 can be effectively exuded.

  The reversal of the photoreceptor 1 is preferably performed at the end of one operation of image formation. One operation referred to here is a series of continuous image forming operations. For example, when copying is performed continuously for 50 sheets, the photoconductor 1 is inverted when the copying of 50 sheets is completed. By performing such reversal of the photoreceptor 1 during non-image formation, the efficiency of image formation does not decrease. Further, since the photoreceptor 1 is reversed every time one operation is completed, the lubricant periodically oozes from the blade 30 and is supplied to the blade surface.

  The reversal of the photoreceptor 1 may be performed when the image forming apparatus is turned on. By performing such reversal of the photoreceptor 1 during non-image formation, the efficiency of image formation does not decrease. Further, the reversal of the photosensitive member 1 is performed before the image forming operation (when the power is turned on), so that the lubricant periodically oozes out from the blade 30 and is supplied to the surface of the blade 30.

  The forward / reverse rotation of the photosensitive member 1 is performed by rotating the drive motor in a forward / reverse controlled manner by a control device. Here, the distance at which the photoreceptor 1 is reversed (reversely rotated) in the direction of arrow B is set such that the blade 30 is changed from the shape shown in FIG. As shown, it is a distance that can be extended, and is usually 1 mm or more, preferably 1 to 10 mm. Since the blade 30 can be fully extended by turning over 1 mm or more, it is not necessary to turn over more than 10 mm. Here, “distance” means the length on the circumference where an arbitrary point P on the circumference of the photoreceptor 1 moves to the point Q by rotation.

  The blade 30 can be produced by a conventionally known composition and construction method. The blade 30 contains a lubricant in an elastic body, and materials such as polyurethane, fluorine rubber, silicone rubber, butyl rubber, butadiene rubber, isoprene rubber, nitrile rubber, chloroprene rubber, ethylene propylene rubber, and acrylic rubber are used as the elastic body. can give. Among these, particularly preferred is polyurethane which has little deterioration over time and is strong in abrasion resistance.

  As the polyurethane, a thermosetting polyurethane elastomer (urethane rubber) which can easily obtain high elasticity can be used. The polyurethane elastomer is based on a linear polyester, polyether, polyester amide, prepolymer prepared by reacting with a diisocyanate, polymerized with a chain extender, and cured with heat or an appropriate crosslinking agent. Alternatively, it is produced by a one-shot method in which a polyol, diisocyanate, chain extender and crosslinking agent are mixed and reacted at the same time to obtain an elastomer.

As the molding method, molding can be performed using a conventionally known kneading method or casting method, but molding by a casting method that can keep equipment costs low is preferable.
In particular, the production molding method for obtaining a polyurethane elastomer by mixing a prepolymer having an isocyanate group at a terminal and a polyol or polyamine as a main chain extender and then heat-curing after casting is one of the most adopted methods at present. One.

  Examples of the polyol component include polyester polyol, which is a condensate of alkylene glycol and aliphatic dibasic acid, ethylene adipate ester polyol, butylene adipate ester polyol, hexylene adipate ester polyol, ethylene propylene adipate ester polyol, and ethylene butylene adipate ester polyol. Polyester polyols such as polyester polyols of alkylene glycol and adipic acid such as ethylene neopentylene adipate ester polyol, polycaprolactone polyols such as polycaprolactone ester polyol obtained by ring-opening polymerization of caprolactone, polyoxytetramethylene glycol Polyether polyol such as polyoxypropylene glycol It is possible to have. Other low molecular weight polyols include, for example, 1,4-butanediol, ethylene glycol, neopentyl glycol, hydroquinone-bis-2-hydroxyethyl ether, 3,3′-dichloro-4,4′-diaminodiph. Dihydric alcohols such as enylmethane, 4,4'-diaminodiphenylmethane, 1,1,1-trimethylolpropane, glycerin, 1,2,6-hexanetriol, 1,2,4-butanetriol, tri Trivalent and higher polyhydric alcohols such as methylolethane, 1,1,1-trishydroxyethoxymethylpropane, diglycerin, pentaerythritol and the like can be used, but are not limited thereto.

  As isocyanate components, 1,5-naphthalene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, hexamethylene diisocyanate, paraphenylene diisocyanate, 2-chloro 1,4 phenyl diisocyanate, tolylene diisocyanate, 4,4 -Diphenylmethane diisocyanate, dianisidine diisocyanate, tridenic diisocyanate, metaxylylene diisocyanate and the like can be used, but are not limited thereto.

As the chain extender, bifunctional, for example, water, glycol, diamine, amino alcohol and the like can be used as a chain extender containing an active hydrogen group, but it is not limited thereto.

  Examples of the lubricant to be contained in the blade 30 include synthetic waxes such as olefin waxes and ester waxes, various natural waxes such as carnauba wax and candelilla wax, higher fatty acids such as stearic acid and palmitic acid, zinc threaphosphate, stearin. Metal soaps such as magnesium acid, fatty acid amides such as lauric acid amide, oleic acid amide, and palmitic acid amide, fatty acid esters, polytetrafluoroethylene, polytrifluoroethylene, polyvinylidene fluoride-containing resin particles, silicone resin Particles, silicone oil such as dimethyl silicone oil, phenylmethyl silicone oil, chlorophenyl silicone oil, and hydrofluorether, perfluoropolyether oil, etc. Liquid lubricants such as animal oils such as base oils, animal oils such as squalane oil, vegetable oils such as rapeseed oil, safflower oil, sesame oil, and coconut oil, and inorganic lubricants such as carbon, molybdenum disulfide, and metal oxides. It is not limited to this.

Of these lubricants, liquid lubricants such as oil are particularly preferable. The effect is easy to obtain the oil in a small amount.
Even more preferably, non-reactive fluorine-based oil is preferable. There is no alteration such as oxidation during the manufacturing process of the cleaning blade and long-term use, the bleeding is stable, and the image bearing member is not physically or chemically damaged. Here, the term “non-reactive” means that there is no reactive group that reacts with the polyurethane material of the blade matrix, and no isocyanate group, hydroxyl group, or amine group. Examples of typical non-reactive fluorine-based oils include fluoropolyether and hydrofluoroether .
Examples of the fluoropolyether include demnum manufactured by Daikin Industries, and examples of the hydrofluoroether include Novec manufactured by Sumitomo 3M.

  The fluorinated oil is mixed in the blade 30 in the range of 1.0 to 20% by weight in the bulk composition ratio (ratio of the fluorinated oil in the entire blade (that is, the total of the polyurethane and the fluorinated oil)). desirable. Within this range, the blade strength can be sufficiently secured, and the fluorine-based oil has a bulk composition ratio of 1.0 to 20% by weight oozes out over the blade surface over a long period of time, and lowers the contact resistance between the blade surface and the photoreceptor surface. This ensures good cleaning properties over a long period of time, prevents the cleaning blade from turning up or generating abnormal noise, prevents blade edge chipping, and further extends the life of the blade.

  On the other hand, when the fluorine-based oil mixed in the blade 30 is less than 1.0% by weight in terms of the bulk composition ratio, the bleeding period of the fluorine-based oil is shortened. Tends to weaken and the blade edge is liable to be chipped.

Here, a molding method to which the prepolymer method is applied as an example of manufacturing the blade 30 will be described below.
First, a cleaning blade mold is prepared, and a holder to be a support member is disposed. Next, a prepolymer obtained by mixing polyisocyanate and polyester polyol and partially polymerizing in advance, a fluorinated oil, a urethane curing catalyst, and a chain extender are put into a casting machine and stirred in a mixing chamber. A liquid mixture is obtained. The elastic blade member made of polyurethane elastomer containing fluorine-based oil is molded on the holder by injecting this into the mold, reacting and curing, then demolding the cured product, and cutting to a predetermined size. Blade 30 can be manufactured.

  Next, the present invention will be described more specifically with reference to examples.

<Production of electrophotographic photoreceptor>
As a conductive support, an undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following composition are sequentially applied on an aluminum cylinder having an outer diameter of 30 mm by dip coating. This was dried to form a 3.5 μm undercoat layer, a 0.2 μm charge generation layer, and a 22 μm charge transport layer.

[Composition of coating liquid for undercoat layer]
・ Alkyd resin 6 parts by mass
(Beckosol 1307-60-EL, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Melamine resin 4 parts by mass
(Super Becamine G-821-60, manufactured by Dainippon Ink & Chemicals, Inc.)
・ 40 parts by mass of titanium oxide (CR-EL: manufactured by Ishihara Sangyo Co., Ltd.)
・ Methyl ethyl ketone 50 parts by mass

[Composition of coating solution for charge generation layer]
In the following formulation, a 10% solid content solution of bisazo pigment and methyl ethyl ketone was ball milled with zirconia balls for 10 days. This pigment dispersion was added to a solution in which the remaining materials were mixed and dissolved, stirred well, and then filtered through a 1000 mesh stainless steel mesh to prepare a coating solution.
・ 2.5 parts by mass of bisazo pigment having the following structure

・ 0.5 parts by weight of polyvinyl butyral (XYHL, manufactured by UCC)
・ 200 parts by mass of cyclohexanone
・ Methyl ethyl ketone 80 parts by mass

[Composition of coating solution for charge transport layer]
・ Bisphenol Z polycarbonate 10 parts by mass
(Panlite TS-2050, manufactured by Teijin Chemicals Ltd.)
・ 7 parts by mass of low molecular charge transport material with the following structural formula

・ 100 parts by mass of tetrahydrofuran
・ 1 mass part of 1% silicone oil in tetrahydrofuran
(KF50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

<Production of cleaning blade>
(Cleaning blade A)
Toluene diisocyanate / polyester base prepolymer (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate 4048) was dissolved by heating at 85 ° C. in a dry nitrogen atmosphere and degassed under reduced pressure at 85 ° C. and 5 mmHg. Daikin Industries Co., Ltd., demnum S-65) 13 parts by mass of 85 ° C. polyol (Nippon Polyurethane Industry Co., Ltd., NIPPOLAN 4009) 113 parts by mass were added, stirred for 20 seconds and poured into a mold, 120 ° C. for 60 minutes. After heating, the mold was released, and a curing treatment was performed at 120 ° C. for 10 hours. The obtained sheet-like cleaning blade was cut into a strip shape to obtain a cleaning blade A.
In addition, the addition amount of fluorine oil is 5.0 mass% in bulk composition ratio (ratio of the fluorine oil which occupies for the whole braid | blade).

(Cleaning blade B)
Cleaning blade except that 101.3 parts by mass of 85 ° C. polyol (Nippon Polyurethane Industry Co., Ltd., Nippon Run 4009) mixed with 1.3 parts by mass of fluorine oil (Daikin Kogyo Co., Ltd., demnum S-65) was used as the polyol. A cleaning blade B was obtained in the same manner as in preparation of A.
The amount of fluorine oil added is 0.52% by mass in bulk composition ratio.

(Cleaning blade C)
Preparation of cleaning blade A except that 182 parts by mass of 85 ° C. polyol (Nippon Polyurethane Industry Co., Ltd., Nippon Polan 4009) mixed with 82 parts by mass of fluorine oil (Daikin Kogyo Co., Ltd., demnum S-65) was used as the polyol. In the same manner, a cleaning blade C was obtained.
The amount of fluorine oil added is 24.8% by mass in bulk composition ratio.

(Cleaning blade D)
Cleaning blade except that 2.51 parts by mass of a fluorinated oil (Daikin Kogyo Co., Ltd., demnum S-65) 2.51 parts by mass as a polyol was used except that 102.51 parts by mass of a 85 ° C. polyol (Nippon Polyurethane Industry Co., Ltd., Nippon Polan 4009) was used. A cleaning blade D was obtained in the same manner as in preparation of A.
The amount of fluorine oil added is 1.0% by mass in bulk composition ratio.

(Cleaning blade E)
Preparation of cleaning blade A, except that 162 parts by mass of 85 ° C. polyol (Nippon Polyurethane Industry, Nippon Polan 4009) mixed with 62 parts by mass of fluorine oil (Daikin Kogyo Co., Ltd., demnum S-65) as the polyol Similarly, a cleaning blade E was obtained.
The amount of fluorine oil added is 20.0% by mass in bulk composition ratio.

(Cleaning blade F)
A cleaning blade F was obtained in the same manner as the cleaning blade A except that acrylic modified silicone fine particles (manufactured by Nissin Chemical Industry Co., Ltd., Charine R170S) were used instead of the fluorine oil.

(Cleaning blade G)
Preparation of cleaning blade A, except that 100 parts by weight of 85 ° C. polyol (Nippon Polyurethane Industry Co., Ltd., Nippon Poly Industries 4009) not mixed with fluorine oil was used instead of 85 ° C. polyol mixed with fluorine oil as the polyol. In the same manner as above, a cleaning breaker G was obtained.

[Example 1]
The Ricoh IPSiO color 7000 remodeled machine is further remodeled by rotating 1 mm for each operation, the photoconductor and the cleaning blade A are set, and a copy test of 100 sheets per operation is repeated to obtain a total of 100,000 images. Formation was performed, and the cleaning property and occurrence of abnormality were evaluated. In this image formation, even in the 100,000-sheet test, the cleaning property was excellent, and abnormalities such as abnormal noise from the blade, chipping of the blade, and turning of the blade did not occur. The evaluation results are summarized in Table 1.
The cleaning property was evaluated as x when a streak-like image was generated, Δ when it was slightly generated, and ○ when it was not generated. In addition, the occurrence of other abnormalities was evaluated by the occurrence of cleaning blade turning and abnormal noise.

[Example 2]
An image was formed and evaluated in the same manner as in Example 1 except that the cleaning blade B was set instead of the cleaning blade A. In this image formation, up to 50,000 sheets were excellent in cleaning properties, and abnormal noise such as blade noise, blade chipping, and blade turning did not occur. An abnormal noise from the blade was generated, but it was at a level that was not a problem for practical use. The evaluation results are summarized in Table 1.

Example 3
An image was formed and evaluated in the same manner as in Example 1 except that the cleaning blade C was set instead of the cleaning blade A. In this image formation, up to 50,000 sheets were excellent in cleaning properties, and no abnormal noise such as blade noise, blade chipping or blade turning occurred, but a slight streak-like image was generated at 100,000 sheets. Although there was a chipping at the tip of the blade. However, it was a level with no problem in practical use. The evaluation results are summarized in Table 1.

Example 4
An image was formed and evaluated in the same manner as in Example 1 except that the cleaning blade D was set instead of the cleaning blade A. In this image formation, even in the 100,000-sheet test, the cleaning property was excellent, and abnormalities such as abnormal noise from the blade, chipping of the blade, and turning of the blade did not occur. The evaluation results are summarized in Table 1.

Example 5
An image was formed and evaluated in the same manner as in Example 1 except that the cleaning blade E was set instead of the cleaning blade A. In this image formation, even in the 100,000-sheet test, the cleaning property was excellent, and abnormalities such as abnormal noise from the blade, chipping of the blade, and turning of the blade did not occur. The evaluation results are summarized in Table 1.

[ Reference Example 6]
An image was formed and evaluated in the same manner as in Example 1 except that the cleaning blade F was set instead of the cleaning blade A. In this image formation, although up to 50,000 sheets were excellent in cleaning properties, a slight blade noise was generated, and a slight streak image was generated at 100,000 sheets. However, in this example, since the lubricant was a solid fine powder acrylic-modified silicone, it was confirmed that the effect of the lubricant was weaker than that of Example 1 using oil. The evaluation results are summarized in Table 1.

Example 7
The Ricoh IPSiO color 7000 remodeled machine is further remodeled by 1 mm when the power is turned on, the photoconductor and the cleaning blade A are set, the power is turned on, 100 copies are continuously printed, and the power is turned off. Then, the power was turned on again and 100 copies of the copy test were repeated, and a total of 100,000 images were formed, and the cleaning property and occurrence of abnormality were evaluated. In this image formation, even in the 100,000-sheet test, the cleaning property was excellent, and abnormalities such as abnormal noise from the blade, chipping of the blade, and turning of the blade did not occur. The evaluation results are summarized in Table 1.

[Comparative Example 1]
Set the cleaning blade A on the IPSiO color 7000 remodeled machine manufactured by Ricoh Co., Ltd., which has not been remodeled so that the photoconductor rotates in reverse, and repeat the copy test to form a total of 100,000 images. evaluated. In this image formation, since the image bearing member is not reversed, the tip of the cleaning blade is expanded or contracted by 10 μm to 30 μm by stick slip, and the fluorine oil contained in the cleaning blade sufficiently oozes onto the blade surface. Therefore, up to 10,000 sheets were excellent in cleaning properties, and abnormal noise such as blade noise, blade chipping and blade turning did not occur. It has occurred. Furthermore, blade turning occurred up to 100,000 sheets. The evaluation results are summarized in Table 1.

[Comparative Example 2]
An image was formed and evaluated in the same manner as in Comparative Example 1 except that the cleaning blade G was set instead of the cleaning blade A. In this image formation, since the cleaning blade does not contain a lubricant, the contact resistance between the surface of the cleaning blade and the surface of the photoreceptor is high, and streaky images are generated with 10,000 sheets, and abnormal noise is also generated. . Furthermore, because blade turning occurred up to 50,000 sheets, the subsequent evaluation was stopped. The evaluation results are summarized in Table 1.

[Comparative Example 3]
An image was formed and evaluated in the same manner as in Example 1 except that the cleaning blade G was set instead of the cleaning blade A. In this image formation, since the cleaning blade does not contain a lubricant, contact resistance between the cleaning blade surface and the photoreceptor surface does not decrease even when rotated reversely, and a streak-like image is generated with 10,000 sheets. Sound was also generated. Furthermore, because blade turning occurred up to 50,000 sheets, the subsequent evaluation was stopped. The evaluation results are summarized in Table 1.

1 Photoconductor (image carrier)
2 Charging device 3 Image exposure unit 4 Developing device 5 Transfer device 6 Cleaning device 8 Fixing device 9 Static elimination lamp 10 Paper feed tray 20 Image forming device 30 Cleaning blade

JP 2002-72713 A JP 2006-106232 A JP-A-3-269478 Japanese Patent Laid-Open No. 5-127445 JP 2000-13320 A Japanese Patent No. 3508914 JP-A-6-59602 JP 2000-330438 A JP 2000-244517 A JP 2004-144818 A

Claims (6)

An image forming apparatus comprising: a photosensitive member rotated in a predetermined direction; and a cleaning device for removing toner powder on the photosensitive member by at least one blade disposed in contact with the photosensitive member. the blade contains a lubricant made of polyurethane, lubricant is either fluorine-based oil chosen from fluoropolyether and hydrofluoroethers, and the predetermined direction the photosensitive body at a predetermined timing The image forming apparatus is driven to rotate in the opposite direction to the image forming apparatus. The image forming apparatus according to claim 1, wherein the fluorine-based oil is mixed in an amount of 1.0 to 20% by weight in a bulk composition ratio. The reverse rotation of the photosensitive body, the image forming apparatus according to claim 1 or 2, characterized in that takes place at one end of the operation of the image forming. The reverse rotation of the photosensitive body, the image forming apparatus according to claim 1 or 2, characterized in that is performed before the operation of the image forming. The image forming apparatus according to any one of claims 1 to 4, wherein a distance to be rotationally driven in a reverse direction of the photosensitive member is 1 mm or more. The distance that rotates in the opposite direction of the photosensitive member, an image forming apparatus according to any one of claims 1-5, characterized in that the 1 to 10 mm.

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