JP2007114373A - Cleaning device, process cartridge and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning device for an image forming apparatus which stably maintains cleaning performance over a long term by stably restraining the friction of a cleaning blade, the end flange of a rotating body, an end sealing member and a scooping sheet or the like to be low over a long term, thereby improving the stability of the shape of material and preventing the increase of adhesion by contaminant resulting from contamination or deterioration by an ozone product. <P>SOLUTION: A resin layer containing fluororesin cross-linked by irradiation of an electron beam under an inert gaseous atmosphere is formed at a spot where the cleaning device abuts on the photoreceptor drum. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cleaning device used in an image forming apparatus such as an electrostatic recording type copying machine or a laser beam printer, a process cartridge having the cleaning device, and an image forming apparatus.

  Image forming apparatuses such as copiers, printers, and facsimiles that perform image formation by electrophotographic method electrostatically transfer a toner image formed on the surface of an image carrier (photosensitive drum) onto a transfer material such as paper. To obtain an output image.

  In such an image forming apparatus, residual toner (untransferred toner) that is not transferred to a transfer material during transfer but remains on the photosensitive drum as it is is sufficiently removed (cleaning) each time for the next image formation. It is necessary to.

  Therefore, as shown in the sectional view in FIGS. 2 and 3, a cleaning blade 100 in which a blade portion 100b made of an elastic material is formed on a support member 100a is generally used as the cleaning means, and the blade portion 100b is used. Are in contact uniformly along the longitudinal direction of the photosensitive drum 101. Here, when the photosensitive drum 101 rotates, the residual toner on the photosensitive drum 101 is scraped off and removed by the cleaning blade 100.

  By the way, if the cleaning blade 100 is merely in contact with the photosensitive drum, the toner scraped off by the cleaning blade 100 is scattered in the apparatus, and therefore the cleaning blade 100 is usually attached to the cleaning container 103. The toner scraped off by the cleaning blade is stored in the cleaning container 103.

  The cleaning blade 100 is in contact with the photosensitive drum 101, and the toner scraped by the cleaning blade 100 is accommodated in the cleaning container 103 on the upstream side (lower part in the drawing) of the cleaning blade with respect to the rotation direction. In addition, a squeeze sheet 102 is usually provided to prevent the toner collected in the cleaning container 103 from leaking out of the cleaning container 103 again. The squeeze sheet 102 is arranged very narrowly so that the toner scraped off between the squeeze drum 101 and the photosensitive drum 101 does not leak. Usually, the squeeze sheet 102 is weakly touched so that the residual toner on the surface of the photosensitive drum 101 is not scraped off. Yes.

  FIG. 4 shows the situation of FIG. 3 viewed from the upper side of the figure.

  End seal members 104 are provided at both ends in the longitudinal direction of the cleaning blade 100 to prevent residual toner from leaking out of the clean container from both ends of the opening provided to store the scraped toner. is doing. Further, the end seal member 104 has an end seal portion 104 a that overlaps the downstream side of the end portion in order to prevent toner from leaking from the end portion of the cleaning blade 100.

  A drum flange 105 is formed on the drum end portion of the photosensitive drum 101 so as to be substantially the same cylinder as the latent image forming portion so that a step difference from the photosensitive drum 101 cannot be formed. The end seal portion 104 is in contact with the drum flange 105 so as to face the drum flange 105.

  Note that the end seal portion 104 may be in contact with only the drum flange 105, or may be in contact with the latent image forming portion of the photosensitive drum 101 overlapping the cleaning blade 100.

  The cleaning blade 100 is turned so that a high frictional force is generated at the contact portion by the rotation of the photosensitive drum 101 so that the blade portion 100b of the cleaning blade 100 is dragged in the rotation direction of the photosensitive drum 101, or on the surface of the blade portion. The provided resin (for example, nylon (trademark)) coat sometimes peeled off.

  The end seal members 104 at both ends in the longitudinal direction of the cleaning device adhere a flame retardant polyurethane foam as a cushion layer on the adhesive layer, and high-density polyethylene or felt having good slipperiness through the adhesive layer. The toner seal function is provided at the end of the cleaning unit of the cleaning device by contacting the rotating member such as a photosensitive drum.

  The seal member 104 and the photosensitive drum 101 are rubbed against each other so that the seal contact portion of the rotating object such as the photosensitive drum is damaged, or the seal member 104 is deformed by long-term use due to the friction between the seal part and the rotating object. There is a problem that becomes worse.

  In the cleaning device, all the toner scraped off by the cleaning blade 100 by the squeeze sheet 102 is accommodated in the cleaning container 103. This squeeze sheet 102 is usually a very thin PET (polyethylene terephthalate) resin film (30 to 70 μm). Or urethane rubber sheets (about 0.5 mm) are used.

  Usually, the squeeze sheet 102 is brought into contact with the photosensitive drum 101 very weakly so as not to damage the photosensitive drum 101. However, there may be a problem that toner or the like adheres and fuses to a part of the film, resulting in a partial contact failure, or the toner fused to the film damages the surface of the photosensitive drum.

  Among these problems, in particular, means for reducing the friction of the cleaning blade in order to prevent end turning of the blade is disclosed in, for example, Patent Documents 1 to 3 and the like. This is because a graphite powder having a low friction coefficient is dispersed in an organic solvent solution of a resin such as polyamide, and a plate-like cleaning blade is dipped in it, applied, and then dried, heated and cured from the resin layer. A coating layer is formed. As described above, the reduction of the friction of the cleaning blade and the reduction of the friction at the end of the blade have a certain effect in preventing the blade from turning up.

  On the other hand, in the absence of oxygen, under conditions of absorbed doses of 1 kGy to 10 MGy, a raw material fluororesin heated to the melting point or higher is irradiated with ionizing radiation to obtain a modified fluororesin excellent in sliding characteristics (Patent Document 4). ). There is also a proposal to apply this modified fluororesin to a fixing member of an electrophotographic image forming apparatus (Patent Documents 5 to 8, etc.). However, this modified fluororesin is not used for improving a cleaning member such as a cleaning blade of an electrophotographic image forming apparatus.

  2. Description of the Related Art In recent years, there has been a demand for more advanced cleaning technology in response to demands for increasing the speed of image forming apparatuses and increasing the image quality of images, as well as the demand for toner spheroidization and the long life of photosensitive drums.

  Further, the fluorinated graphite used in the blade having the coating layer described above is a substance that is very easy to wear, although the effect of reducing friction is high but the Mohs hardness is as low as 1-2. For this reason, the fluorinated graphite that appears on the surface after long-term use is worn away and friction increases. That is, although the friction is small in the initial stage, there is a problem that the effect of reducing the friction is lost after long-term use.

  In addition, not only fluorinated graphite, but also conventional fluororesins such as PTFE with a relatively low molecular weight, problems such as durability and shape stability, contamination and deterioration by ozone products occur. However, sufficient performance was not obtained.

  In addition, the squeeze sheet and the end seal member have a problem in that adhesion due to contaminants increases due to durability, shape stability, and contamination and degradation by ozone products.

In order to solve these problems, attempts have been made to improve slipperiness and adhesion by using a general fluororesin film. However, in the case of a general fluororesin, the wear resistance is PET or polyethylene. In addition, the film has poor rigidity, so that not only the problem of toner adhesion but also the stability of the shape of the material is not sufficient.
Japanese Patent Laid-Open No. 04-212190 Japanese Patent Laid-Open No. 04-240887 Japanese Patent Laid-Open No. 04-245283 JP 09-278907 A JP 2003-140494 A JP 2004-004156 A JP 2002-274728 A Japanese Patent Laying-Open No. 2005-084160

  That is, the problem of the present invention is that the friction of the cleaning blade, the end flange of the rotating body, the end seal member, the squeeze sheet, etc. is stably kept low over a long period of time, the stability of the shape of the material, the contamination and deterioration by the ozone product It is an object of the present invention to provide a cleaning device for an image forming apparatus that prevents an increase in adhesion due to contaminants and maintains a cleaning performance stably over a long period of time.

  The present inventor has intensively studied to solve the above-described problems, and includes a fluororesin in which a portion of various members used for a cleaning device provided for cleaning the surface of the photosensitive drum that is in contact with the photosensitive drum is crosslinked by a specific treatment. The present inventors have found that the above problems can be achieved by coating with a resin, and have reached the present invention.

  That is, according to the present invention, in a cleaning device that removes toner remaining on an image carrier of an image forming apparatus, a member that contacts or contacts the image carrier (hereinafter referred to as “cleaning member”) contacts the image carrier. Alternatively, a resin layer containing a fluororesin (hereinafter referred to as “crosslinked fluororesin”) crosslinked by electron beam irradiation in an inert gas atmosphere is formed in a contact portion (hereinafter referred to as “contact portion”). This is a cleaning device.

  The cleaning member is preferably a cleaning blade, a cleaning container end seal member, or a squeeze sheet.

  Further, the present invention is an electron beam irradiation in which an electron beam irradiation in an inert gas atmosphere results in an absorbed dose of 1 kGy to 10 MGy in an atmosphere having an oxygen partial pressure of 13 kPa or less. It is the above-described cleaning device which is fluoroethylene (PTFE) or tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA).

  The wear amount of the crosslinked fluororesin-containing resin layer is preferably 2 μm or less in terms of wear thickness with respect to the sliding distance of 42.8 km.

Moreover, it is more preferable that the resin layer containing a crosslinked fluororesin has a thickness of 17 to 27 μm and a surface roughness (10-point average roughness, Rz _jis ) of 3 μm or less.

  Here, the crosslinked fluororesin is more preferably a powder having an average particle size of 8 μm or less.

  Furthermore, when the cleaning member has a contact pressure on the image carrier of 20 to 80 N / m, the wear amount of the resin layer containing the crosslinked fluororesin is less than 2 μm with respect to the sliding distance of 42.8 km. A certain cleaning blade is more preferable.

  Furthermore, the present invention is a process cartridge for an image forming apparatus or an image forming apparatus having the cleaning device described above.

  The cleaning device of the present invention comprises a member formed with a resin layer containing a fluororesin that has been cross-linked by irradiation with an electron beam in an inert gas atmosphere, such as a cleaning blade, an end seal member, or a squeeze sheet. Since it is used, friction from these members against the photosensitive drum can be kept stable and low over a long period of time, toner is prevented from adhering to these members, and the surface of the photosensitive drum can be damaged. The member that is in contact with the photosensitive drum is almost eliminated, and the shape of the member is kept stable. Therefore, the cleaning device of the present invention has very good performance for cleaning the surface of the photosensitive drum.

  The present invention will be described in detail below.

  The present invention relates to a cleaning device that is used in contact with a photosensitive drum of an image forming apparatus, scrapes off toner remaining when a toner image is transferred onto the photosensitive drum, and cleans the surface of the photosensitive drum. The characteristic feature is that a cross-linked fluororesin is applied to a part in contact with or in contact with a photosensitive drum such as a cleaning blade, a squeeze sheet, or an end seal member such as a cleaning blade, a squeeze sheet, or an end seal member. The resin layer to be contained is formed.

  The cross-linked fluororesin used in the present invention is a fluororesin that is cross-linked by irradiation with an electron beam in an inert gas atmosphere. Note that the uncrosslinked fluororesin or the fluororesin that has been irradiated with an electron beam in an active gas atmosphere has insufficient wear resistance, and the effects of the present invention cannot be obtained.

  This cross-linked fluororesin can be produced, for example, by the production method described in JP2003-12815A. That is, raw material fluororesin, for example, polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-ethylene A powder such as a copolymer (ETFE) is placed in an inert gas atmosphere, preferably in an atmosphere having an oxygen partial pressure of 13 kPa or less. Usually, the temperature is equal to or higher than the melting point of the raw fluororesin, preferably 10 to 30 from the melting point. It is obtained by irradiating with an electron beam at a high temperature. The reason why the electron beam irradiation is performed at a temperature higher than the melting point is that the main chain cannot sufficiently move at a temperature lower than the melting point of the raw fluororesin, and the main chain is cut without crosslinking between the main chains. This is because the strength of the fluororesin may not be sufficient. In addition, as long as the oxygen partial pressure is 13 kPa or less, it may be in the state of an atmospheric gas composed of an inert gas such as nitrogen, argon, or helium. When considering irradiation efficiency and the like, it may be under reduced pressure. Furthermore, the obtained fluororesin powder that has been irradiated with the electron beam is pulverized and classified to obtain a crosslinked fluororesin excellent in abrasion resistance used in the present invention. However, since the pulverization may be difficult as it is, the pulverization can be easily performed by irradiating the electron beam again if necessary, so that the electron beam can be further irradiated. Note that the second electron beam irradiation need not be performed under an inert gas atmosphere.

  The electron beam dose is preferably 1 kGy to 10 MGy as the absorbed dose. If this irradiation amount is present, a crosslinked fluororesin having a sufficient degree of crosslinking required in the present invention can be obtained.

  In addition, it is suitable that it is 1MGy or less as a 2nd electron beam irradiation amount irradiated as needed. Since the second electron beam irradiation is for improving the pulverization of the electron beam irradiated fluororesin, it is preferable that the second electron beam irradiation is previously pulverized after the first electron beam irradiation. Then, classify with a sieve or the like. The crosslinked fluororesin powder preferably has an average particle size of 8 μm or less.

  The above-mentioned cross-linked fluororesin powder is disposed in a form dispersed in a resin material corresponding to the material of the cleaning member at a location where it contacts or comes into contact with the photosensitive drum of the cleaning member. For example, in a cleaning blade, the blade material in contact with the photosensitive drum is often made of a polyurethane resin because of its elasticity, strength, and ease of manufacture. Therefore, a polyamide resin is usually rubbed as a resin material for dispersing the crosslinked fluororesin powder. Used because of good resistance.

  Such a polyamide resin is made into a paint, for example, from Toray Industries, Inc. under the trade name Platamide (M1276, M995, CM4000, CM8000, etc.) and from Nagase Chemitex Co., Ltd. under the trade name Resin (F30). , MF30, EF30T, etc.), any of which can be used in the present invention.

  In the present invention, such a polyamide resin coating liquid is usually applied to the cleaning member in contact with or in contact with the photosensitive drum, together with the necessary conductive agent, stabilizer, etc. Drying to obtain the cleaning member of the present invention.

  In addition, when it is possible to attach a fluororesin film instead of the surface formation with such a paint, it is possible to use a film obtained by crosslinking a fluororesin film under the electron beam irradiation conditions. That is, a film having an appropriate thickness, for example, a cleaning blade of 1 to 50 μm, preferably 2 to 30 μm, which has been subjected to a crosslinking treatment under the electron beam irradiation conditions as described above may be adhered and pasted. .

  Fluoropolymers have excellent properties such as heat resistance, chemical resistance, solvent resistance, and electrical characteristics. Therefore, using these characteristics, they are frequently used as engineering plastics or as solid lubricants and coating materials. ing. However, it is known that the fluororesin itself is inferior in wear resistance and can be improved by irradiation with radiation in an inert gas. The present invention is characterized by using a fluororesin modified by electron beam irradiation in an inert gas atmosphere as described above, that is, a cross-linked fluororesin.

  The cleaning member for forming the coating layer containing the cross-linked fluororesin is a cleaning blade, a squeeze sheet, or an end seal member. These may be formed by forming a layer containing a cross-linked fluororesin instead of forming a coating layer (treatment layer) on the surface of a member conventionally used.

  For example, with a cleaning blade, trimming is performed by forming a blade member that contacts the photosensitive drum on a metal support member with an elastic material such as polyurethane resin and directly molding it, or removing it as necessary. Use the processed one.

  When a polyurethane resin is used as a blade member, a polyol component, a polyisocyanate component, and the like that have been conventionally used as the blade can be used without any problem. Moreover, conventionally well-known things can be used also about the various additives added as needed. Further, the molding method may be to form polyurethane resin as a micro-foamed sheet having a required thickness and cut out from the sheet to a predetermined size. Also, a support member is placed on a cleaning blade molding die, and a polyurethane raw material is placed there. It may be by injection hardening. A coating film containing a cross-linked fluororesin is formed on the contact portion between the blade member and the photosensitive drum. In addition, it may replace with coating-film formation and you may stick a crosslinked fluororesin film.

  An example of such a cleaning blade is shown in FIG. In FIG. 1, a cleaning blade 100 has a blade member 100b made of polyurethane resin or the like attached to a metal support member 100a, and the bridge member 100b is in contact with a photosensitive drum (not shown). Since the resin layer containing the fluororesin powder or the cross-linked fluororesin film layer 100c is formed, the reliability of the cleaning blade is improved.

  Further, since the squeeze sheet is used in a state where it is weakly in contact with the surface of the photosensitive drum, it is required to be a sheet having a certain degree of rigidity, mechanical strength and flexibility, and is usually a sheet made of polyethylene terephthalate, polyurethane rubber or the like. Is used. A coating film containing a cross-linked fluororesin is formed or a cross-linked fluororesin film is attached to a portion of such a sheet that weakly contacts the photosensitive drum. In addition, when a crosslinked fluororesin film has sufficient thickness and intensity | strength, it is good also as attaching to a cleaning container directly and making it a squeeze sheet | seat.

  Although the end seal member is not as clean as the cleaning blade, it is rubbed against the photosensitive drum surface or drum flange surface, so it may be made of fluororesin due to its excellent slidability. There is a problem that the rubbing property is inferior, and a gap is formed immediately and the cleaning blade leaks out the toner. Therefore, the end seal member is required to have cushioning and rubbing resistance, and usually a thin sheet-like foamed elastic body provided with a rubbing-resistant resin film is used. As the foamed elastic body, a polyurethane foam resin is often used, and the surface resin is often made of a high molecular weight polyethylene having a small friction coefficient. In the present invention, a coating film containing a crosslinked fluororesin is formed on the surface, or a crosslinked fluororesin film is attached.

  By incorporating the cleaning member obtained as described above into the cleaning device, the surface of the photosensitive drum can be stabilized and a good cleaning effect can be achieved over a long period of time. That is, these cleaning members are preferable as members of a cleaning device used for an image forming apparatus and a process cartridge. In the electrophotographic color image forming apparatus, when transferring each color image to a recording medium, a transfer roller and a transfer film for temporarily transferring and integrating these images are used. In such a color image forming apparatus, the cleaning device of the present invention can be used not only for cleaning the photosensitive drum but also for cleaning the transfer roller and transfer film. In this case, the squeeze sheet and the end seal member are not necessarily provided.

  Hereinafter, the present invention will be described by way of examples.

Reference Example 1 Production of cross-linked fluororesin powder “cross-linked powder A” PTFE molding powder (G-163, manufactured by Asahi Glass Co., Ltd.) having an average particle size of 40 μm was heated to 350 ° C. to form PTFE in a slightly fused state. This was placed at 335 ° C. in nitrogen gas having an oxygen concentration partial pressure of 66 Pa or less, and irradiated with an electron beam (acceleration voltage 1 MeV) so that the absorbed dose was 100 kGy. Next, this was pulverized by a jet mill until the average particle size became 27 μm, and the passage through a 200 mesh sieve was collected. The obtained powder was irradiated with an electron beam having an absorbed dose in air of 30 kGy at room temperature, and pulverized again with a jet mill to obtain a cross-linked PTFE powder “cross-linked powder A” having an average particle diameter of 8 μm. In addition, the electron beam irradiation apparatus used here is an electron beam irradiation apparatus electron shower (trade name) manufactured by Denki Kogyo Co., Ltd.

  Further, although the first electron beam irradiation was examined in the air, the fluororesin deteriorated and a good crosslinked fluororesin powder could not be obtained.

Reference Example 2 Production of Electron Beam Irradiated Fluoropolymer Film An electron beam (accelerated) at 350 ° C. under an oxygen partial pressure of 66 Pa (0.5 torr) and nitrogen atmosphere against a 20 μm thick PFA tube sheet (manufactured by Gunze Co., Ltd.) A voltage of 1 MeV) is applied so that the irradiation dose is 100 kGy or 50 kGy, and then one surface of the surface is modified with a solution containing about 1% of metallic sodium in liquid ammonia, and then irradiated with an electron beam. Resin films (hereinafter referred to as “irradiated film A” and “irradiated film B”, respectively) were obtained.

Reference Example 3 Production of Cleaning Blade Body 100 parts by mass of ethylene adipate urethane prepolymer (manufactured by Nippon Polyurethane Industry Co., Ltd., Mn = 1500, NCO = 6.2% by mass) and 1.4-butanediol 3 as a curing agent .9 parts by mass and 2.1 parts by mass of trimethylolpropane were mixed to prepare a urethane rubber raw material, and then poured into a cleaning blade mold charged with a SUS support sheet metal coated with an adhesive. After heating and vulcanizing for 30 minutes and demolding, secondary vulcanization was performed in a thermostatic chamber at 130 ° C. for 4 hours to produce a cleaning blade body in which urethane rubber was bonded to a support metal plate. The rubber portion had a width of 20 mm and a thickness of 2 mm, a JISA rubber hardness of 77 °, a compressive strain (70 ° C.) of 9%, and a rebound resilience of 40%.

Example 1
Polyamide-based coating resin “Platamide M995” (trade name, manufactured by Toray Industries, Inc.) 20 parts by mass is dissolved in 100 parts by mass of methyl alcohol, and fluorinated graphite (trade name, Cefbon DM, manufactured by Central Glass Co., Ltd.) 1 The tip of the cleaning blade body prepared in Reference Example 3 is immersed in 2 parts by mass of the mass part and the crosslinked powder A (manufactured in Reference Example 1) and uniformly dried, and then 130 ° C. for 10 minutes. Heat drying was performed to form a coat layer having an average thickness of 12 μm. Next, the cleaning blade 1 was obtained by adjusting the linearity of the tip of the blade with a cutter.

Example 2
A cleaning blade 2 having an average thickness of the coating layer of 17 μm was obtained in the same manner as in Example 1 except that the amount of the crosslinked powder A used was 5 parts by mass.

Comparative Example 1
A cleaning blade 3 having an average coating layer thickness of 17 μm was obtained in the same manner as in Example 1 except that the cross-linked powder A was not used and graphite fluoride was increased to 3 parts by mass instead.

Comparative Example 2
The average thickness of the coating layer is the same as in Example 1 except that polyvinylidene fluoride powder (trade name: Kyner 500, manufactured by Penwort, adjusted to an average particle size of 8 μm) is used instead of the crosslinked powder A. A cleaning blade 4 of 17 μm was obtained.

  These cleaning blades are mounted on the photosensitive drum cleaning device of each color copying unit of a tandem-type electrophotographic full-color copying machine (manufactured by Canon, CLC5000). , 80% RH).

  The setting conditions were a process speed of 200 mm / sec, a cleaning blade contact pressure (linear pressure) of 30 g / cm, a contact angle of 27 °, and a free length of 7 mm.

  Under high temperature and high humidity where blade turning is likely to occur, toner is supplied to the blade and a certain number of sheets (initial: 100 sheets, durability: 70,000 sheets) are copied (using A4 paper), then the developer is removed. It was confirmed that the blade was not turned over when 50 sheets of copying operation was performed without toner being supplied to the blade portion. The results are shown in Table 1.

  Further, after finishing the endurance, the cross-linked fluororesin-containing coating layer of the cleaning blade was observed to examine whether peeling occurred. In addition, it was also examined whether there was a lack of cleaning (due through) during durability. These results are also shown in Table 1.

  In addition, these evaluations were made into 3 ranks of "(circle): It did not generate | occur | produce", "(DELTA): It may generate | occur | produce", and (x: It generate | occur | produced).

  As can be seen in Example 1, the coating layer in which the electron beam cross-linked fluororesin powder is added to the fluorinated graphite does not cause blade turning even after durability. Further, as seen in Example 2, there is no problem even if the blending amount of the electron beam crosslinked fluororesin powder is increased. On the other hand, in the case of using only fluorinated graphite (Comparative Example 1), blade turning sometimes occurred in the forced blade turning test after durability. Moreover, peeling and slipping-out were not observed in the fluororesin powder not subjected to electron beam crosslinking (Comparative Example 2), but in the forced blade turning test, blade turning may occur at an initial stage, and after the endurance, Blade turning occurred. That is, it has been found that it is preferable to provide the electron beam cross-linked fluororesin-containing coating layer on the rubbing surface of the cleaning blade with the photosensitive drum.

  Note that the cleaning blade 2, the cleaning blade 3, and the cleaning blade body prepared in Reference Example 3 provided with no coating layer were used, and the influence of the contact pressure on the photosensitive drum was examined. The results are shown in Table 2. The end of the blade after endurance was photographed, and the amount of wear was also examined and shown in Table 2 in comparison with the photograph before incorporation into the copying machine. Note that the tip wear amount is 42.8 km when the cleaning blade is in contact with the photosensitive drum and the tip wear amount is 100,000 sheets. Therefore, the actual wear amount after 70,000 sheets durability is converted by calculation. Is.

  When the cleaning blade 2 of Example 2 is used, toner slips out when the contact pressure is 10 g / cm, and no slip occurs when the contact pressure is 20 g / cm or more. Even when the contact pressure was increased to 80 g / cm, the blade was not turned up. Even at a contact pressure of 80 g / cm, the amount of wear at the tip was 1 μm / 100,000 sheets or less.

  On the other hand, when the cleaning blade 3 of Comparative Example 1 was used, the blade turned up when the contact pressure was increased to 30 g / cm or more. The slip-through was good from the contact pressure of 20 g / cm, but the tip wear was 5 μm / 100,000 at the contact pressure of 20 g / cm, and further wear when the contact pressure was 30 g / cm or more. The amount has grown.

  When the main body (prepared in Reference Example 3) with no coating on the surface was used as a urethane rubber blade as it was, the blade turned up during the durability even at a contact pressure of 10 g / cm.

Examples 3-7
The cleaning blades 5-9 are the same as in Example 2 except that the coating of the cross-linked fluororesin powder-containing resin layer is applied so that the thickness of the coat layer is about 10 μm, about 15 μm, about 20 μm, about 25 μm, or about 30 μm. And mounted on the tandem type electrophotographic full-color copying machine, with a process speed of 200 mm / sec, a cleaning blade contact angle of 27 °, a contact pressure of 30 g / cm, and a free length of 7 mm to prevent initial toner slip-through. Examined.

  The evaluation results are shown in Table 3.

The thickness of the coat layer is an average value obtained by observing five points in the longitudinal direction of the cross section of the cleaning blade under a microscope. The initial surface roughness Rz _jis is an average value obtained by measuring three points at a cut off of 0.25 and a measurement length of 1.25 mm. The initial surface roughness tended to increase when the coat layer was thin.

When the coating layer thickness was as thin as 12 μm, the initial surface roughness was large, and the occurrence of slip-through was observed. Further, when the coat layer thickness was thick, the rubber elasticity was impaired and the surface layer became hard, and slipping through occurred at 32 μm.

  As described above, it was found that good cleaning performance was obtained when the coating layer thickness was 17 μm to 27 μm.

Example 8
The irradiation film A produced in Reference Example 2 is adhered to the portion of the cleaning blade body produced in Reference Example 3 that contacts the photosensitive drum with a double-sided tape (trade name: Y9448, manufactured by Sumitomo 3M), and the cleaning blade 10 Got.

Example 9
A cleaning blade 11 was obtained in the same manner as in Example 8 except that the irradiated film B was used in place of the irradiated film A.

Comparative Example 2
A cleaning blade 12 was obtained in the same manner as in Example 8 except that a PFA tube sheet (manufactured by Gunze Co., Ltd.) having a thickness of 20 μm was used instead of the irradiation film A.

  These cleaning blades 10 to 12 were used as cleaning blades and mounted in the above-described tandem type electrophotographic full-color copying machine, and the blade turning and cleaning properties after 70,000 sheets were examined under high temperature and high humidity. The experimental conditions were a process speed of 200 mm / sec, a cleaning blade contact angle of 27 °, and a free length of 7 mm.

  The examination results are shown in Table 4.

  As shown in Table 4, those with a PFA sheet with an irradiation dose of 100 kGy or 50 KGy had no cleaning failure and no edge wear for those with a contact pressure of 20 g / cm or higher. It was also confirmed that the blades were not turned up even when the contact pressure was increased to 80 g / cm. On the other hand, the PFA film that had not been irradiated with an electron beam at all was durable and slipped through, and the amount of wear was large.

Example 12
A PTFE sheet having a thickness of 0.05 mm is irradiated with an electron beam (acceleration voltage 1 MeV) at a heating temperature of 340 ° C. in a nitrogen atmosphere with an oxygen concentration of 10 ⁻⁵ mol / g so as to give an irradiation dose of 100 kGy. _Thus , a crosslinked fluororesin sheet having a surface roughness Rz _jis of 0.8 μm (cut off 0.25) was produced. The non-electron beam-irradiated surface of this sheet was subjected to an adhesive treatment with a solution containing about 1% metallic sodium in liquid ammonia, and pasted with 3 mm thick polyurethane foam using a double-sided tape (trade name: Y9448). This laminated sheet was attached to the cleaning container as a sealing member so that the crosslinked PTFE surface was in contact with the drum flange, and a cleaning device was produced. The drum flange was formed by injection molding of polycarbonate resin to which 20% by weight of the crosslinked powder A prepared in Reference Example 1 and 15% by weight of carbon fluoride were added.

Comparative Examples 5 and 6
In place of the modified fluororesin sheet, a high-density polyethylene film having a thickness of 0.5 mm or a commercially available PTFE film having a thickness of 0.05 mm (trade name: Scotch 5490, manufactured by Sumitomo 3M Limited) was used as in the cleaning device of Example 12. Was made.

The cleaning device produced in Example 12 and Comparative Examples 5 and 6 is mounted on the tandem type electrophotographic full-color copying machine, and 60,000 images are formed in a high-temperature and high-humidity environment and a low-humidity environment. Toner leakage from the end seal member, toner adhesion on the seal surface, wear of the seal, and scratches on the photosensitive drum were observed. Table 5 shows the evaluation results. The experimental conditions were set as a process speed of 200 mm / sec and a seal surface pressure of 10 gf / cm ² . The photosensitive drum is a Canon organic photosensitive drum having a charge generation layer, a charge transport layer, a release layer, and the like.

  As shown in Table 5, in Example 12, there were no problems in terms of seal wear, toner leakage, photosensitive drum scratches and sheet contamination. In addition, the amount of sheet wear was measured by measuring the level difference using a surface roughness meter. Further, even when rotation equivalent to 100,000 sheets was performed for a sheet thickness of 50 μm, the amount of wear was 0.5 μm or less, and there was no problem in practical use. On the other hand, in the high-density polyethylene sheet of Comparative Example 5, the toner was fused to the sheet surface, and stains were generated. Further, the prevention of toner leakage was not sufficient. Further, scratches were generated at the end of the photosensitive drum. As shown in Comparative Example 6, in the fluororesin tape without electron beam irradiation, the seal part was 10,000 sheets, and the sheet was severely damaged. In addition, toner adheres from this scratch. That is, it was found that when a cross-linked fluororesin sheet is used for the end seal, there is a great effect in improving the cleaning performance.

Example 13
Polyamide-based coating resin “Platamide M995” (trade name) 20 parts by mass is dissolved in 100 parts by mass of methyl alcohol, 3 parts by mass of graphite fluoride (trade name, Cefbon DM) and crosslinked powder A (produced in Reference Example 1) 3 While the mass part is uniformly mixed, a 0.5 mm thick urethane rubber sheet is cut into the required shape as a squeeze sheet and the end of the sheet that contacts the photosensitive drum is dipped to form a coating layer. After natural drying The film layer was formed by heating and drying at 130 ° C. for 10 minutes. In order to maintain the linearity of the front end of the sheet having the coating layer containing the obtained cross-linked fluororesin, the sheet was cut with a cutter after drying to prepare a squeeze sheet.

  The obtained squeeze sheet was attached to a cleaning device and mounted on the above-described tandem type electrophotographic full-color copying machine, 60,000 images were formed in a high-temperature and high-humidity environment, and toner leakage from the cleaning device was observed. . The results are shown in Table 6. Experimental conditions were set as a process speed of 200 mm / sec, a squeeze sheet contact angle of 17 °, a free length of 15 mm, and an entry amount of 3 mm. As the photosensitive drum, a Canon organic photosensitive drum having a charge generation layer, a charge transport layer, a release layer, and the like was used.

Comparative Examples 7 and 8
As a squeeze sheet, a 0.5 mm thick urethane rubber sheet or a 50 μm thick polyethylene terephthalate (PET) film was used, and toner leakage was examined in the same manner as in Example 13. The results are shown in Table 6.

  In the urethane rubber sheet (Comparative Example 7), a wave was observed at the tip after endurance, the adhesion between the photosensitive drum and the sheet partially occurred, and toner leakage partially occurred. Further, in the PET film (Comparative Example 8), the toner and the external additive were fused to a part of the front end portion of the sheet, and the photosensitive drum was scratched. In contrast, in Example 13 in which the cross-linked fluororesin-containing coating layer was formed, no toner leakage, scratches on the photosensitive drum, no tip wave, and no toner fusion to the front end of the sheet occurred, and the performance as a squeeze sheet was high. I understood it.

It is sectional drawing of the cleaning blade of this invention. It is sectional drawing of an example of the conventional cleaning blade. It is sectional drawing which shows typically the relationship between a cleaning apparatus and a photosensitive drum. It is a schematic diagram when it sees from the upper side of sectional drawing in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Cleaning blade 100a Cleaning blade support member 100b Cleaning blade blade part 100c Cross-linked fluororesin-containing coating layer 101 Photosensitive drum 102 Squee sheet 103 Cleaning container 104 End seal member 105 Photosensitive drum flange

Claims (9)

In a cleaning device for removing toner remaining on an image carrier of an image forming apparatus,
A member in contact with or in contact with the image carrier (hereinafter referred to as “cleaning member”) is irradiated with an electron beam in an inert gas atmosphere on a portion in contact with or in contact with the image carrier (hereinafter referred to as “contact portion”). A cleaning device comprising a resin layer containing a crosslinked fluororesin (hereinafter referred to as “crosslinked fluororesin”).   The cleaning device according to claim 1, wherein the cleaning member is a cleaning blade, a cleaning container end seal member, or a squeeze sheet.   Electron beam irradiation under an inert gas atmosphere is an electron beam irradiation under an atmosphere having an oxygen partial pressure of 13 kPa or less, and an absorbed dose of 1 kGy to 10 MGy, and the raw material fluororesin of the crosslinked fluororesin is polytetrafluoroethylene (PTFE) Or the cleaning apparatus of Claim 1 or 2 which is a tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA).   The cleaning device according to claim 1, wherein the wear amount of the cross-linked fluororesin-containing resin layer is 2 μm or less in wear thickness with respect to a sliding distance of 42.8 km. The resin layer containing a cross-linked fluororesin has a thickness of 17 to 27 µm, and a surface roughness (ten-point average roughness, Rz _jis ) of 3 µm or less. Cleaning device.   The cleaning apparatus according to claim 1, wherein the cross-linked fluororesin is a powder having an average particle size of 8 μm or less.   When the cleaning member has a contact pressure to the image bearing member of 20 to 80 N / m, the amount of wear of the resin layer containing the crosslinked fluororesin is less than 2 μm with respect to the sliding distance of 42.8 km. The cleaning device according to claim 1, wherein the cleaning device is a blade.   A process cartridge for an image forming apparatus, comprising the cleaning device according to claim 1.   An image forming apparatus comprising the cleaning device according to claim 1.

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