JP2006227357A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of appropriately cleaning off a toner with a spherical small-diameter, reducing wear due to friction between a blade and an image carrier, and ensuring stable quality for a long time. <P>SOLUTION: The electrophotographic image forming apparatus includes a cleaning device 16 of a blade cleaning system that removes a residual toner on the image carrier. The cleaning device 16 is in contact with a photoreceptor drum 2 such that its blade 21 applies a contact pressure of 1 Mpa or more to the photoreceptor drum 2. The cleaning roller 16 is also provided with a device that forms a lubricant layer onto the surface of a photoreceptor drum 2 by a coating roller 23 disposed in contact with a lubricant agent 22. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrophotographic image forming apparatus.

  In Patent Document 1, the developer has a shape factor SF1 of 100 to 150, and the cleaning means has an elastic blade that contacts the image carrier with a contact pressure of 55 gf / cm to 105 gf / cm. A technique is disclosed in which at least 0.4 kg of lubricant is applied by the mechanism until the rotational driving distance of the image carrier reaches 525 m.

  Patent Document 2 discloses a technique for providing a lubricant application means for applying a lubricant to the surface of a cleaning member, and reducing the amount of lubricant applied to the longitudinal center region of the member to be cleaned more than that to both longitudinal end regions. It is disclosed.

Patent Document 3 has a lubricant application device, the linear pressure of the cleaning blade against the image carrier is 0.2 to 0.5 N / cm, the contact angle is 22 to 32 °, the rebound resilience of the blade material is 45 to 65%, 300% modulus is disclosed a technique is 1000~2500N / cm ^2.

  In Patent Document 4, in an electrophotographic image forming method having a cleaning blade, zinc stearate is contained in the toner in an amount of 0.01% or more and 0.5% or less with respect to the toner weight. A technique that is substantially held on the photoreceptor contact surface side is disclosed.

  In Patent Document 5, the developer has a shape factor SF1 of 100 to 150, and the cleaning means has an elastic blade that contacts the image carrier with a contact pressure of 55 gf / cm to 105 gf / cm. A technique for applying a lubricant to the surface of a photosensitive drum by rotating a lubricant and a lubricant application roller arranged so that the lubricant and the photosensitive drum are in contact with each other is disclosed.

Patent Document 6 discloses a thermoplastic resin in which the blade has a 300% tensile stress at 50 ° C. of 50 kgf / cm ² or more.

JP 2000-075752 A JP 2002-55580 A JP 2003-58009 A Japanese Patent Laid-Open No. 11-184340 JP 11-288194 A JP-A-8-36338

  In the electrophotographic forming method, a positive or negative charge is uniformly charged on the surface of the image carrier using a charging unit, and then exposure is performed according to an image to form an electrostatic latent image. The developing device develops the latent image with toner charged to a polarity opposite to that of the electrostatic latent image on the image carrier, and transfers the toner image onto a transfer paper such as paper or an intermediate transfer medium using a transfer unit. The transfer residual toner on the image bearing member is removed from the image bearing member by the cleaning device, and is circulated to the charging means without toner on the surface of the photosensitive drum, so that it can be used repeatedly.

  As this cleaning device, there are known cleaning devices such as a blade cleaning method, a conductive or insulating fur brush roller method, and a magnetic brush cleaning method in which magnetic powder is magnetized on the surface of the magnetic roller. The brush cleaning and magnetic brush cleaning devices have drawbacks such as complicated mechanisms and conditions, increasing the size of the device, and increasing costs. Therefore, a blade cleaning method is often used as an inexpensive method.

  The cleaning device of the blade cleaning system is parallel to the surface of the image carrier, goes straight in the moving direction of the surface of the image carrier, and has a predetermined amount of free end length on the blade support member fixed to the casing supporting the image carrier. In order to clean the surface of the image carrier, a cleaning blade is attached in the counter direction toward the surface of the image carrier. The contact pressure of cleaning, the cleaning angle, the hardness of the cleaning blade, the material of the cleaning blade, the free end length (protrusion amount) of the cleaning blade, and the thickness of the cleaning blade are optimized according to the linear velocity of the image carrier. Due to poor cleaning due to toner slipping or chipping of the blade edge, noise and chatter between the blade and the image carrier, turning of the blade, adhesion of toner additives or paper dust to the surface of the image carrier due to insufficient blade scraping performance Conditions are set so that an abnormal image does not occur due to the filming that occurs.

  By the way, in recent electrophotographic methods and the like, the toner tends to have a smaller particle size in order to improve the image quality of 2400 dpi or the like. The reduction in toner particle diameter is in the direction that makes it difficult to clean the toner, and it is more difficult to ensure a sufficient cleaning capacity for the transfer residual toner on the image carrier. In the production of toner, a polymerization method has become mainstream for energy saving. In the polymerization method, it is most advantageous in terms of cost to use a spherical shape without the step of deforming the toner shape. By making it spherical, the transfer efficiency is improved, the amount of toner remaining as a transfer residual toner is reduced, and the energy saving effect is further increased.

  However, as a means for achieving high image quality in recent years, such a spheroidization of the toner shape or a reduction in the particle size of the toner has been promoted, and the reduction in the toner particle size is applied to the latent image carrier. As a result, the van der Waals force is increased and it becomes difficult to clean the surface of the latent image carrier with a conventional cleaning blade.

  Accordingly, it has been found that, as a measure for improvement, it is possible to clean a small-diameter and spherical toner by increasing the linear pressure between the blade and the image carrier. However, generally increasing the pressing pressure to increase the linear pressure causes problems such as wear of the surface layer and blade of the image carrier and scratches on the surface of the image carrier. If the friction coefficient of the photosensitive drum is large, the blade also increases the amount of deformation of the blade, which causes problems such as toner slip-through, blade squealing, and chatter.

  Further, it has been considered that the blade cleaning system functions well if it can be brought into contact with the image carrier without a gap with a uniform pressing force according to the adhesive force between the blade and the image carrier. Further, as such a blade body, a plate-shaped molded product made of polyurethane elastomer is cut to a predetermined size to be a blade member, and is generally bonded and integrated to a steel support plate via an adhesive. It is used. In addition, an adhesive is applied to the support plate in advance and dried, and this is attached to the mold, and a polyurethane elastomer forming liquid is injected into the mold to cause a crosslinking effect. Those formed by bonding to a support plate are also known. These blade bodies are usually used in pressure contact with an image carrier in order to obtain cleaning properties. When used in pressure contact, it is necessary to suppress a decrease in pressure contact over time in order to exert its function over a long period of time. Therefore, the blade member itself has less permanent distortion, i.e., less sag. Various attempts have been made.

  However, as the toner becomes smaller in particle size to increase the resolution of the image, a strong and uniform pressure contact force is required. In contrast, the blade material is improved and the elastic plate is bonded to the steel support plate. There is a limit to the blade body made of steel just made, and it has become difficult to cope with it.

  In particular, the target toner so far has been easily dammed by contacting the blade with pulverized toner. However, it has been found that when the circularity of the toner becomes high or the diameter becomes small, it is difficult to dam the toner simply by contacting the blade. This is because the pulverized toner adhering to the image bearing member can easily slide on the image bearing member just by hitting the blade and dam the toner, but if the toner has a high degree of circularity, The adhesive force becomes a rotational moment by contact with the blade. This rotational moment becomes a force under the blade, and the toner rubs through the blade while rotating to cause a cleaning failure. In order to prevent this, it is necessary to apply pressure to the tip of the blade to prevent subtraction due to moment.

  Until now, as a method of increasing this pressure (generally referred to as linear pressure), the blade hardness has been increased, the blade protrusion length has been shortened, and the blade thickness has been increased. There have been methods such as increasing the amount of biting between the blade and the image carrier and increasing the spring strength of the blade support plate.

  However, when the hardness of the blade is increased, the blade itself is plasticized and plastically deformed, and the linear pressure initially increases, but the linear pressure decreases with time, resulting in a creep phenomenon. Further, since the hardness is high, there is a problem in uniform contact with the image carrier, and problems such as partial cleaning failure occur.

  Shortening the protruding amount of the blade increases the natural frequency of the blade itself, which causes problems such as increased “squealing” and “chatter”. In addition, thickening only wastes material carelessly, and there is a problem in economy.

  Furthermore, increasing the bite and the spring load changes the position of the support plate, which is a metal, but the rubber material itself is only pressed against the image carrier, causing the blade to hit the belly, and the blade and the image carrier. Although the contact area of the toner increases and the linear pressure improves, the force to effectively prevent the toner from slipping through cannot be obtained.

  Here, considering the above-mentioned Patent Documents 1 to 6, since the technique of Patent Document 1 only defines the linear pressure within a certain range, if the contact area with the image carrier increases, the unit area is added. The pressure becomes small, and the cleaning performance cannot be sufficiently obtained for toner having a high sphericity of SF1 of 100 to 150. Moreover, since the period of lubricant application is a relatively initial period, it can be said that long-term reliability and durability are lacking.

  In the technique of Patent Document 2, since the amount of lubricant applied varies in the longitudinal region of the image carrier, the coefficient of friction on the surface of the image carrier becomes non-uniform, resulting in uniform cleaning and blade wear. However, there is a drawback that uniformity cannot be obtained.

  In the technique of Patent Document 3, the linear pressure is defined in a relatively small region, but since it is not defined what surface pressure is applied to the image carrier, it is difficult to dampen the small diameter toner. It is. Further, since the prescribed value of the rebound resilience is high, the movement of the contact portion of the blade with the image carrier becomes intense. This is because the stick-slip motion is large, and this significantly hinders the action of blocking the small-diameter toner. This intense behavior increases the wear and damage of the blade and reduces its durability.

  In the technique of Patent Document 4, since the attachment direction of the blade to the support plate is the direction of peeling when pressed against the image carrier, the contact pressure between the peeled image carrier and the blade is reduced when pressed against the image carrier for a long time. Gradually decreases. As a result, it is difficult to maintain the cleanability of the spherical / small-diameter toner.

  In the technique of Patent Document 5, since the contact pressure between the blade and the image carrier is defined by a linear pressure, toner cleaning with high sphericity between the image carrier and the blade is difficult by simply pressing the blade.

  Further, in the technique of Patent Document 6, since a thermoplastic resin is used for the blade, the coefficient of restitution and hardness change are large due to environmental fluctuations, and the wear resistance is inferior.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus capable of appropriately cleaning spherical and small-diameter toners and reducing wear due to friction between a blade and an image carrier, and having stable quality for a long period of time. .

  According to a first aspect of the present invention, in the electrophotographic image forming apparatus provided with a cleaning device that removes residual toner on the image carrier by a blade cleaning method, the cleaning device has a blade contact pressure of 1 Mpa or more. The image forming apparatus further comprises means for contacting the image carrier and forming a lubricating layer on the surface of the image carrier.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the blade includes a blade body and a support plate that supports the blade body, and one side plane of the support plate and the blade body. The flat surface of the step portion is joined, and the thickness portion of the support plate and the step portion of the blade body are joined.
According to a third aspect of the present invention, in the image forming apparatus according to the first aspect, the blade is abutted in a state where a tip portion thereof is a cut surface and is in contact with the image carrier. To do.
According to a fourth aspect of the present invention, in the image forming apparatus according to the second aspect, the blade body is a rubber blade having a rubber hardness (JISA hardness) in a range of 65 ° to 80 °. And
According to a fifth aspect of the present invention, in the image forming apparatus according to the second aspect, the thickness of the tail end portion of the blade body is larger than the thickness of the tip portion, and the sum of the thicknesses of the support plate and the tip portion. It is characterized by being smaller.
According to a sixth aspect of the present invention, in the image forming apparatus according to the first aspect, the coefficient of friction between the blade and the image carrier is 0.8 or less and greater than zero.
According to a seventh aspect of the present invention, in the image forming apparatus according to the fourth aspect, the blade body has a rebound resilience coefficient at 23 ° C. of 30% or less, greater than 0%, and a change rate of 10 ° C. to 40 ° C. It is characterized by being a rubber blade of 350% or less and greater than 0%.
According to an eighth aspect of the present invention, in the image forming apparatus according to the first aspect, the means for forming the lubricating layer forms the lubricating layer by rotating a roller for applying a lubricant in a predetermined direction. It is characterized by this.
According to a ninth aspect of the present invention, in the image forming apparatus according to the first aspect, the means for forming the lubricating layer is obtained by mixing the lubricant with a developer for developing a latent image on the image carrier. Is coated on the image carrier by rotation of a roller.

According to a tenth aspect of the present invention, in the image forming apparatus according to any one of the first to ninth aspects, the cleaning device and at least one of the image carrier, the developing device, and the charging device are integrated. The process cartridge is structured to be detachable from the main body of the image forming apparatus.
According to an eleventh aspect of the present invention, in the image forming apparatus according to any one of the first to ninth aspects, a plurality of the image carriers are provided, and toner images of different colors are provided on the image carriers. Means for forming and superimposing the toner images of the respective colors to form a color image, and forming the cleaning device and the lubricating layer are provided for each image carrier.

  According to the first aspect of the present invention, it is possible to appropriately clean spherical and small-diameter toner, reduce wear due to friction between the blade and the image carrier, and provide an image forming apparatus having a stable quality for a long period of time. Can be provided.

According to the second aspect of the present invention, a high surface pressure can be formed between the blade and the image carrier, and the spherical and small diameter toner can be appropriately cleaned.
According to the third aspect of the present invention, the adhesion between the blade and the image carrier can be ensured, the local cleaning failure can be eliminated, and the uniform cleaning performance can be maintained.
According to the fourth aspect of the present invention, since the elastic force can be maintained without permanent deformation of the blade, and the medium hardness, the surface pressure can be maintained and the contact with the uniform image bearing member can be achieved. Durability can be secured.
According to the fifth aspect of the present invention, the surface pressure can be secured, and good cleaning properties can be obtained by the uniform contact with the image carrier.
According to the sixth aspect of the invention, the blade life is extended by preventing the blade from being worn, and the adhesion between the toner and the image carrier can be reduced and the cleaning property is improved.
According to the invention of claim 7, stable cleaning quality can be obtained.
According to the eighth aspect of the present invention, the toner adhesion is reduced and the cleaning property is improved, the blade can be prevented from being caught, the wear of the blade and the image carrier can be reduced, and the durability is improved.
According to the ninth aspect of the present invention, the lubricating layer can be formed on the image carrier at a low running cost, and the durability is improved.

According to the tenth aspect of the present invention, the downsizing of the apparatus and the operability of the detachment / exchange are improved.
According to the eleventh aspect of the present invention, the apparatus can be easily downsized and operated.

Hereinafter, the best mode for carrying out the present invention will be described.
FIG. 1 is an explanatory diagram of a schematic configuration of an electrophotographic image forming apparatus 1 according to the present embodiment. In FIG. 1, there are a charging device 3 for charging the surface of the photosensitive drum 2 with a charging roller or the like around the photosensitive drum 2 as an image bearing member, and a latent beam on the uniformly charged surface of the photosensitive drum 2 with a laser beam or the like. An exposure device 4 for forming an image, a developing device 6 for forming a toner image by attaching a charged toner to a latent image on the photosensitive drum 2, a transfer belt or a transfer roller, a charger and the like on the photosensitive drum 2. A transfer device 12a for transferring the formed toner image to the recording paper 9, a cleaning device 16 for removing toner remaining on the image carrier photosensitive drum 2 after transfer, and a residual potential on the image carrier photosensitive drum 2 are removed. The neutralizing device 18 and the like are arranged.

  In such a configuration, the photosensitive drum 2 whose surface is uniformly charged by the charging roller of the charging device 3 forms an electrostatic latent image by the exposure 4 and forms a toner image by the developing device 6. The toner image is transferred from the surface of the image carrier photosensitive drum 2 to the recording paper conveyed by the paper feed roller 10 from the paper feed tray 9 by the transfer device 12a. Thereafter, the toner image on the recording paper is fixed on the recording paper by the fixing device 14. On the other hand, the toner remaining on the image carrier drum without being transferred is collected by the cleaning device 16. The photosensitive drum 2 from which the residual toner has been removed is initialized by the charge eliminating lamp 18 and used for the next image forming process.

Next, the cleaning device 16 will be described.
FIG. 2 is an explanatory diagram of the cleaning device 16. The cleaning device 16 is a blade 21 cleaning system, and a means for forming a lubricating layer on the surface of the photosensitive drum 2 is provided in front of the blade 21 so that the friction coefficient of the surface of the photosensitive drum 2 does not fluctuate. That is, the lubricant 22 is brought into contact with the application roller 23, and a lubricant layer is formed on the surface of the photosensitive drum 2 by the application roller 23.

  FIG. 3 is a graph showing the relationship between the surface pressure of the blade 21 and the cleaning property obtained by experiments with such a configuration. The surface pressure is a value obtained by dividing the force of the blade 21 applied to the photosensitive drum 2 by the contact area of the blade 21. Here, the contact area can be easily measured by applying the blade 21 to the transparent pseudo photosensitive drum 2 with a force equivalent to that of the actual machine. The cleaning property of the blade 21 is a characteristic value obtained by transferring the toner remaining on the photosensitive drum 2 after a predetermined pattern image is transferred onto a recording sheet to a tape and using the remaining toner as an image density. It is determined that the larger the value is, the larger the remaining number of toners is, and the cleaning property is inferior. In general, if the remaining ID in FIG. 3 is 0.025 or more, cleaning is poor, and if it is less than that, it is considered good. Good cleaning was obtained when the surface pressure at this time was 1 Mpa or more.

  FIG. 4A shows a schematic configuration diagram of the blade 21. 4A is enlarged as shown in FIG. 4B, and the cutting surface of the blade 21 is in contact with the photosensitive drum 2 while being turned by the movement of the photosensitive drum 2. FIG. FIG. 4C shows a pressure vector at each mesh node, which is a distribution of the surface pressure, and an integrated one is the surface pressure.

  As shown in FIG. 5, the blade 21 includes a support plate 24 and a rubber blade (blade main body) 25, and one side flat portion of the support plate 24 and the flat surface of the step portion of the blade main body 25 are joined. Furthermore, the thickness part of the support plate 24 and the step part of the blade 21 are joined. By joining the thickness portion of the support plate 24 and the step portion of the blade 21, when the blade 21 is pressed against the photosensitive drum 2, the moment of bending deformation of the blade 21 is received without buckling at the step portion. Therefore, it is possible to apply pressure to the photosensitive drum 2 in a straight state without buckling.

  FIG. 6A shows a contact state of the blade 21 having the conventional configuration. At this time, the blade body 25 is buckled and deformed at the thickness step portion of the support plate 24. In such a deformed state, the cutting surface at the tip of the blade 21 does not turn over, and the distribution of surface pressure becomes a group of small pressure vectors as shown in FIG. The pressure of the unit area becomes small, and the force to block the small diameter toner cannot be obtained.

  On the other hand, the blade 21 of the present embodiment is shown in FIGS. Since the cutting surface at the tip of the blade body 25 is turned over, the contact portion with the photosensitive drum 2 remains only at the tip portion, and the portion where the rear end side of the blade 21 contacts the photosensitive drum 2 is small. can get. Thus, the pressure distribution is completely different depending on whether the same force (linear pressure) is received with a small contact area or a large area. The ability to dam the small-diameter toner is completely different by applying a surface pressure as shown in FIG.

  FIG. 8 is a graph showing the relationship between the amount of biting of the blade 21 and the surface pressure using the rubber hardness as a parameter, and further showing a region distribution with good cleaning properties at that time. From this, it can be seen that the surface pressure increases simply by increasing the amount of bite. In order to obtain a surface pressure of 1 Mpa or more, it is only necessary to bite 0.05 mm at a rubber hardness of 90 °. However, when the photosensitive drum 2 actually rotates, the deflection amount is 0.1 mm, and the component accuracy and contact of the blade 21 There is a variation of 0.2mm due to variation. Therefore, if a material having a high rubber hardness is used in a state where the amount of biting is small, contact unevenness between the blade 21 and the photosensitive drum 2 occurs, and uniform cleaning performance cannot be obtained.

  Based on these examination results, the amount of bite is required to be 0.5 mm or more considering the environmental margin. Therefore, in order to ensure the surface pressure of the blade 21 and to secure a region with good cleaning, the rubber hardness is preferably in the range of 65 ° to 80 °.

  In order to bring the blade 21 into uniform contact with the photosensitive drum 2 and to obtain a stable cleaning performance, a configuration that allows the blade 21 to easily become familiar with the photosensitive drum 2 is essential.

  Therefore, as shown in FIG. 5, the blade 21 is not simply a shape having a uniform thickness, but L2 that improves the contact property between the L1 region (tail end portion) that presses the tip end portion of the blade 21 and the photosensitive drum 2. This region (tip portion) is provided, and the thickness is set to satisfy “t2 + t3> t4> t1”. Thereby, it is possible to prevent resonance such as “squeal” and “chatter” due to the blade 21 being rubbed against the photosensitive drum 2.

  The coefficient of friction between the blade 21 and the photosensitive drum 2 is calculated by measuring the force applied to the blade 21 by measuring each axial force with a three-component force meter. That is, the normal force N and tangential force F to the photosensitive drum 2 are measured, and the friction coefficient μ is expressed by F / N.

  FIG. 9 shows the measurement results of the acting force with and without lubricant application. From this result, when the normal force is increased, the tangential acting force increases linearly when there is no lubricant, but when the lubricant is applied, the tangential acting force tends to gradually decrease. The ratio of the tangential force to the normal force at this time, that is, the friction coefficient is about 0.95 when no lubricant is applied, but becomes 0.87 to 0.74 when applied.

  FIG. 10 shows the result of evaluating the cleaning property in this state. The cleaning property tends to deteriorate as the friction coefficient increases, and good results were obtained when the friction coefficient was 0.8 or less (greater than 0).

  For this reason, the force relationship among the toner, the blade 21 and the photosensitive drum 2 will be described with reference to FIG. The toner particles T remaining on the photosensitive drum 2 as residual toner collide with the blade 21, Ntp (adhesive force between the blade 21 and the photosensitive drum 2), Nbtcos θ (reactive force received from the blade 21 on the photosensitive drum 2 method). The resultant force (Ntp + Nbtcosθ) of the linear component) is applied. Due to this resultant force, the friction coefficient (μ1) between the toner and the photosensitive drum 2 causes the toner particles T to enter the lower surface of the blade 21 with a rotational moment F1 (= μ1 × (Ntp + Nbtcosθ)) and push up the blade 21. On the other hand, the force to prevent this is a reaction force Nbt from the blade 21, and a rotation inhibiting moment F2 (= μ2 × Nbt) of the rotation of the toner particles T acts on the friction coefficient μ2 between the blade 21 and the toner. In other words, it is essential that “F1 <F2” is satisfied so that the toner does not sink. To achieve this, the stopping power can be improved by reducing the friction coefficient μ1. In addition, since the lubricating layer is formed on the surface of the photosensitive drum 2, the blade 21 and the photosensitive drum 2 are not in direct contact with each other, so that wear damage is eliminated and durability is improved.

  The rebound resilience of the blade 21 has such an effect that when the blade 21 cleans the toner, the tip portion in contact with the blade 21 repels the toner. Until now, cleaning of non-spherical pulverized toner and the like has improved the cleaning ability by rebounding when the rebound resilience is larger. However, it was found that the spherical toner dipped into the lower surface of the blade 21 before rebounding and the effect of this action was small. To reduce the impact resilience, the hard segment of the polyurethane component is increased.

  Therefore, it is indispensable to use the low-repulsion blade 21 for the configuration in which the surface pressure becomes a certain value or more as in the present embodiment. FIG. 12 shows the change in the rebound resilience coefficient with respect to the temperature change. The impact resilience coefficient tends to increase with temperature. However, a product having a relatively high rebound resilience at 10 ° C. like the product shown in graph C of FIG. 12 becomes high at 40 ° C., but the rate of change itself has only a fluctuation of about 200%. Further, as in the product shown in the graph B, there is a product having a small rebound resilience at a low temperature and a large rebound resilience coefficient at a high temperature, and the rate of change reaches 600%.

  Experimentally, the product shown in graph B has a stable cleaning performance with 30% or less (greater than 0%) at room temperature and a fluctuation rate of 350% or less (greater than 0%) with respect to temperature change. Obtained.

  In forming the lubricating layer on the surface of the photosensitive drum 2, if the lubricant is brought into direct contact, uneven wear of the lubricant itself and coating uniformity on the photosensitive drum 2 cannot be obtained. Therefore, in order to uniformly apply the lubricant, it is desirable to apply the lubricant 22 indirectly to the photosensitive drum 2 by bringing the lubricant 22 into contact with the application roller 23 as shown in FIG.

  In this method, the amount of application to the photosensitive drum 2 can be easily adjusted by adjusting the rotation speed of the application roller 23. Further, by setting the rotation direction of the application roller 23 as a counter with respect to the rotation direction of the photosensitive drum 2, the residual toner is pre-cleaned by the application roller before entering the blade 21, thereby improving the cleaning performance.

  Here, as the lubricant, a metal soap such as zinc stearate, calcium stearate, magnesium stearate, barium stearate, aluminum stearate, etc. is solidified and applied by rubbing with the application roller 23 to be uniform and stable. A coated film state is obtained.

  Also, the lubricant is applied not by the application roller 23 of the cleaning device 16 but by being mixed in the developer of the developing device 6, and the photosensitive drum 2 is rubbed by a magnetic brush provided on the developing roller of the developing device 6. You may do it. The lubricant used at this time is used in the form of powdered metal soap. As a result, the lubricating layer on the surface of the photosensitive drum 2 can be formed at a low running cost.

  In the image forming apparatus 1, the cleaning device 16, the photosensitive drum 2, the charging device 3 for charging the photosensitive drum 2, and the developing device 6 for developing the electrostatic latent image formed on the photosensitive drum 2 with toner. May be formed as an integrated structure and configured as a process cartridge 17 that can be attached to and detached from the main body of the image forming apparatus 1.

  FIG. 14 shows an example in which the image forming apparatus 1 is configured as a tandem type. 14, members having the same reference numerals as those in FIG. 1 and subsequent figures have the same configuration as that of the above-described image forming apparatus 1, and detailed description thereof will be omitted. That is, the image forming apparatus 1 in FIG. 14 includes a plurality of photosensitive drums 2 serving as image carriers, and forms toner images of different colors, that is, M, C, Y, and K, on the respective photosensitive drums 2. The color toner images are sequentially superimposed on the transfer paper on the transfer belt 25 to form a color image, and the cleaning device 16 and the application roller 23 are provided for each photosensitive drum 2. That is, each color toner image is formed by the process cartridges 17M, 17C, 17Y, and 17B having the same configuration as the process cartridge 17 described above.

1 is an explanatory diagram of a schematic configuration of an electrophotographic image forming apparatus according to an embodiment of the present invention. 1 is an explanatory diagram of an overall configuration of a cleaning device of an image forming apparatus. It is a graph explaining the relationship between surface pressure and the cleaning property of a cleaning apparatus. It is explanatory drawing, such as a structure of the blade of a cleaning apparatus. It is explanatory drawing of the specific structural example of a braid | blade. It is explanatory drawing of the conventional braid | blade. It is explanatory drawing of the braid | blade of this embodiment. It is a graph explaining the relationship between the hardness of a blade, and a linear pressure. It is a graph explaining the difference in the acting force of the blade by the presence or absence of a lubricant. It is explanatory drawing of the relationship between the friction coefficient of a braid | blade, and cleaning property. It is explanatory drawing about the effect | action of a braid | blade at the time of using a spherical toner particle. It is a graph explaining the relationship between the temperature and rebound resilience coefficient in a blade. It is explanatory drawing of the process cartridge provided with the cleaning apparatus. Using process cartridge

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Image carrier 3 Charging apparatus 6 Developing apparatus 16 Cleaning apparatus 21 Blade 22 Means for forming lubricating layer 23 Means for forming lubricating layer

Claims (11)

In an electrophotographic image forming apparatus including a cleaning device that removes residual toner on an image carrier by a blade cleaning method,
The cleaning device is in contact with the image carrier when the contact pressure of the blade is 1 Mpa or more,
Having means for forming a lubricating layer on the surface of the image carrier;
An image forming apparatus.   The blade includes a blade main body and a support plate that supports the blade main body, and a flat surface on one side of the support plate and a flat surface of the stepped portion of the blade main body are joined together, and the thickness portion of the support plate and the blade main body The image forming apparatus according to claim 1, wherein the step portion is joined.   The image forming apparatus according to claim 1, wherein the blade is abutted in a state where a tip portion thereof is a cut surface and is in contact with the image carrier.   The image forming apparatus according to claim 2, wherein the blade body is a rubber blade having a rubber hardness (JISA hardness) in a range of 65 ° to 80 °.   The image forming apparatus according to claim 2, wherein a thickness of a tail end portion of the blade body is larger than a thickness of a tip portion and smaller than a sum of thicknesses of the support plate and the tip portion.   The image forming apparatus according to claim 1, wherein a friction coefficient between the blade and the image carrier is 0.8 or less and greater than 0.   The blade body is a rubber blade having a rebound resilience coefficient at 23 ° C of 30% or less and greater than 0%, and a change rate from 10 ° C to 40 ° C of 350% or less and greater than 0%. 5. The image forming apparatus according to 4.   2. The image forming apparatus according to claim 1, wherein the means for forming the lubricating layer forms the lubricating layer by rotating a roller for applying a lubricant in a predetermined direction.   The means for forming the lubricating layer is characterized in that a mixture of a developer for developing a latent image on the image carrier and the lubricant is contact-coated on the image carrier by rotation of a roller. The image forming apparatus according to claim 1.   The cleaning device and at least one of the image carrier, the developing device, and the charging device have an integrated structure, and constitute a process cartridge that can be attached to and detached from the main body of the image forming apparatus. Item 10. The image forming apparatus according to any one of Items 1 to 9. A plurality of image carriers are provided, toner images of different colors are formed on the respective image carriers, and color images are formed by superimposing the toner images of the respective colors, and the process cartridge is provided for each image carrier. The image forming apparatus according to claim 10, wherein the image forming apparatus is provided.

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