JP2014056046A - Protective agent applicator, process cartridge, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protective agent applicator which reduces driving torque to be required for driving a new protective supply member without requiring complicated operation, thereby reducing cost.SOLUTION: A protective agent applicator 20 includes at least a core bar and a protective agent supply roller (protective agent supply member) 22 having a foam layer formed on the outer periphery of the core bar. The protective agent supply roller 22 is supplied with a protective agent 21, and applies the protective agent 21 onto the surface of a photoreceptor drum (image carrier) 5. For a predetermined time in initial driving of a new protective agent supply roller 22, the protective agent applicator 20 is operated in a protective agent supply mode M, in which the protective agent supply roller 22 is supplied with a protective agent 21 and no protective agent 21 is applied from the protective agent supply roller 22 to the photoreceptor drum 5.

Description

  The present invention relates to a protective agent for an image carrier in an electrophotographic apparatus, a protective agent coating device for forming a protective layer on the surface of the image carrier, an image forming apparatus having the protective agent coating device, and a process cartridge.

  Conventionally, in image formation by electrophotography, a static image is formed on an image carrier such as a photoconductive substance (sometimes referred to as an “electrostatic latent image carrier”, “electrophotographic photosensitive member”, or “photosensitive member”). A latent image is formed by electric charges, and charged toner particles are attached to the electrostatic latent image to form a visible image. The visible image formed by the toner is finally transferred to a recording medium such as paper, and then fixed on the recording medium by heat, pressure, solvent gas, or the like, and becomes an output image.

  This electrophotographic image forming method is based on a so-called two-component development method that uses friction charging by stirring or mixing of toner particles and carrier particles by a method of charging toner particles for visualization, and carrier particles. It is roughly classified into a so-called one-component development method in which charge is imparted to toner particles without using the toner. Of these, the one-component development method is more advantageous than the two-component development method in terms of space saving and cost reduction, and is therefore widely used in small printers and facsimiles.

  In these electrophotographic image forming apparatuses, the image carrier is generally charged while rotating an image carrier such as a drum shape or a belt shape, regardless of the development method, and the image carrier by laser light or the like. A latent image pattern is formed on the body, which is visualized by a developing device, and further transferred onto a recording medium. Further, the toner component that has not been transferred remains on the image carrier after the visible image is transferred to the recording medium. If this residual toner component is conveyed as it is to the charging step, it may hinder the uniform charging of the image carrier. Therefore, in general, the toner component remaining on the image carrier after the transfer step Are removed in a cleaning process to make the surface of the image carrier sufficiently clean, and then charged.

  In recent years, in order to reduce the size and cost of an electrophotographic image forming apparatus, a contact charging method and a proximity charging method are often used in an image forming charging process. However, it is difficult to uniformly charge the surface of the image carrier due to slight contact unevenness between the charging member and the surface of the image carrier, and a gap variation between the charging member and the surface of the image carrier. An AC superposition charging method in which an AC AC component is superposed has been used. The proximity charging method based on AC superposition charging can realize downsizing and high image quality of the apparatus, and at the same time, the charging member and the image carrier can be brought into non-contact while maintaining charging uniformity, thereby suppressing deterioration of the charging member. be able to.

  However, when the image carrier is an organic photoconductor OPC, the AC superposed charging energy cuts the resin chain on the surface of the image carrier, lowers the mechanical strength, and the wear of the image carrier significantly increases. Further, since AC superimposed charging activates the surface of the image carrier, there is a problem that the adhesion between the surface of the image carrier and the toner is increased, and the cleaning performance for the image carrier is reduced.

  On the other hand, since the colorization of output images has progressed recently, development has progressed in the direction of toner particle size reduction and circularization to improve image quality and stabilize image quality. In the image forming method of the type, the problem with respect to cleaning is increasing. In order to clean such toner, since the sliding force of the cleaning member against the image carrier is required more than before, there is a problem that the wear of the image carrier, the cleaning member and the like is remarkably advanced. Thus, electrical stress and physical stress exist in each step of image formation by the electrophotographic method. The surface state of the image carrier subjected to these stresses changes with use time.

  For such problems, it is known that it is effective to apply a protective agent on the image carrier during image formation. For example, a block-shaped protective agent mainly composed of zinc stearate, a proposal for applying a so-called protective agent block on the image carrier, or a protection obtained by adding boron nitride to a protective block mainly composed of zinc stearate. There have been proposals for applying an agent block on an image carrier.

  The application of the protective agent block on the image carrier reduces the friction coefficient on the image carrier to reduce the deterioration of the cleaning blade and the image carrier, and attaches an untransferred toner or the like adhering to the image carrier. It is possible to improve the ability to remove the kimono, and as a result, it is possible to suppress the occurrence of poor cleaning and filming over time.

  Then, as a technique for applying a protective agent block on the image carrier, a protection comprising a protective agent block and a brush-like rotating member that applies the protective agent that contacts the protective agent block and adheres to the surface to the image carrier. There has been proposed a protective agent coating apparatus having a protective agent supply member and a protective agent pressurizing member that pressurizes the protective agent block and contacts the protective agent supply member.

  However, in these proposed techniques, most of the powder of the protective agent rubbed from the protective agent block due to the rotation of the brush-like rotating member (brush roller) cannot remain on the brush surface and in the interior in large quantities. There is a problem that a large amount of protective agent is wasted due to flying. Further, there is a problem in that the brush fibers fall over and deteriorate over time, the consumption of the protective agent is not stable, and the protective agent cannot be supplied in a constant amount over a long period of time.

  Thus, a technique has been proposed in which a roller-shaped protective agent supply member having a foam layer is used as the protective agent supply member of the protective agent application apparatus (see Patent Documents 1 and 2). In the proposed technique, almost no flying of the protective agent powder due to rubbing occurs. This is because the density of the roller is high, so that most of the scraped powder adheres to the roller surface or is taken into the cells of the foam. In addition, there is no influence of brush fall or deterioration, which is a problem with brushes, and it is possible to supply a constant amount of protective agent over a long period of time, and a solid lubricant film can be uniformly formed on the surface of the image carrier with a relatively small amount of consumption. It is said. In addition, it can be manufactured at a relatively low cost compared to brushes, contributing to the cost reduction of the unit.

  However, in the case of a protective agent supply member using a foamed elastic roller (hereinafter also referred to as a roller) configured as in Patent Documents 1 and 2, it is necessary to increase the driving torque as compared with a supply member using a brush that has been used conventionally. There is a problem that there is. This problem is particularly noticeable when the roller is in a new state. The reason for this will be described.

  FIG. 11 is a graph showing the relationship between the travel distance of the image carrier and the driving torque by the driving means such as a motor required for driving the protective agent supply member during the operation of the protective agent applying apparatus described above. In order to efficiently supply the protective agent, the above-described roller is usually configured to rotate while rubbing the surface of the image carrier with a linear velocity difference with respect to the image carrier. This rotation condition is the same for a protective supply member using a brush. However, since the friction coefficient of the roller surface is larger than that of the brush, the roller requires a larger driving torque than the brush. As described above, since the roller has a large coefficient of friction on the surface when it is new, the roller starts to operate with a driving torque that is much larger than the driving torque required for image formation (max 1 in FIG. 11). Then, as the operation continues, the protective agent gradually adheres to the roller surface, so that the friction coefficient of the roller surface gradually decreases, and finally stabilizes at a lower value than when new (FIG. 11). min). In FIG. 11, the point when the driving torque is stabilized at this low value (min) is defined as point A. When selecting a motor for driving the roller, it must be assumed that the maximum torque value (max1) described above is output. There is a problem that a high-spec motor having a high cost has to be selected only for a short period of a new state, that is, a short period from the new point to point A in FIG.

  In order to solve such a problem, as shown in Patent Document 3, a protective agent is applied to the roller in advance to lower the initial surface resistance (surface friction coefficient), and then the unit at the time of image formation It is also possible to assemble it into However, an increase in work time leads to an increase in cost, and further increases the cost of equipment and management for the work. Moreover, since a protective agent is easy to float, there exists a possibility of adhering to other components at the time of an assembly | attachment.

  The present invention can suppress a driving torque required to drive a protective agent supply member when it is new without requiring complicated work, and as a result, a protective agent coating apparatus and process capable of realizing a reduction in cost. It is an object to provide a cartridge and an image forming apparatus.

  In order to achieve this object, the protective agent coating apparatus of the present invention includes at least a roller-shaped protective agent supply member having a cored bar and a foam layer on the outer periphery of the cored bar, and the protective agent supplying member is a protective agent. In the protective agent coating apparatus for applying the protective agent to the surface of the image carrier, the protective agent is supplied to the protective agent supply member for a predetermined time at the initial drive after the replacement of the protective agent supply member. The protective agent supplying member operates in the protective agent supply mode in which the protective agent is not applied to the image carrier.

  According to the present invention, it is possible to suppress the driving torque required when the protective agent supply member is new without requiring a complicated operation, and as a result, it is possible to reduce the cost.

1 is a schematic diagram illustrating an example of an overall configuration of an image forming apparatus including a protective agent coating apparatus according to the present invention. It is a schematic block diagram of the protective agent coating device of embodiment. It is explanatory drawing of the setting method of the average value of the cell number of the foam layer of a protective agent supply roller. It is explanatory drawing of an example of operation | movement of the photoconductor drum of embodiment, and a protective agent supply roller. It is explanatory drawing of the other example of operation | movement of the photosensitive drum of embodiment, and a protective agent supply roller. It is a graph which shows the relationship between the travel distance of an image carrier, and a driving torque at the time of operation | movement of the protective agent coating device of embodiment. It is a schematic explanatory drawing in 1st Embodiment of operation | movement at the time of protective agent supply mode. It is a schematic explanatory drawing in 2nd Embodiment of operation | movement at the time of a protective agent supply mode. It is a schematic explanatory drawing in 3rd Embodiment of the operation | movement at the time of a protective agent supply mode. It is a flowchart which concerns on operation | movement of the protective agent supply mode at the time of providing a torque limiter. It is a graph which shows the relationship between the travel distance of an image carrier, and a driving torque at the time of operation | movement of the conventional protective agent coating device.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

  FIG. 1 is a schematic diagram illustrating the overall configuration of a tandem type color printer which is an embodiment of an image forming apparatus according to the present invention. The outline and operation of the internal configuration of the image forming apparatus will be described with reference to FIG.

  In the bottle housing portion 101 above the image forming apparatus 1, four toner bottles 102Y, 102M, 102C, and 102K corresponding to the respective colors (yellow, magenta, cyan, and black) are detachably (replaceable). Yes.

  An intermediate transfer unit 85 is disposed below the bottle housing portion 101. Image forming units 4Y, 4M, 4C, and 4K corresponding to the respective colors (yellow, magenta, cyan, and black) are arranged in parallel so as to face the intermediate transfer belt 78 of the intermediate transfer unit 85.

  Photosensitive drums 5Y, 5M, 5C, and 5K are disposed in the image forming units 4Y, 4M, 4C, and 4K, respectively. Further, around each of the photosensitive drums 5Y, 5M, 5C, and 5K, a charging unit 75, a developing unit 76, a cleaning unit 77, a charge eliminating unit (not shown), and the like are disposed. Then, an image forming process (charging process, exposure process, development process, transfer process, cleaning process) is performed on each of the photoconductive drums 5Y, 5M, 5C, and 5K. An image of each color is formed on 5K.

  The photosensitive drums 5Y, 5M, 5C, and 5K are rotationally driven in a clockwise direction in FIG. 1 by a drive motor (not shown). Then, the surfaces of the photosensitive drums 5Y, 5M, 5C, and 5K are uniformly charged at the position of the charging unit 75 (a charging process). Thereafter, the surfaces of the photosensitive drums 5Y, 5M, 5C, and 5K reach the irradiation position of the laser beam emitted from the exposure unit 3, and electrostatic latent images corresponding to the respective colors are formed by exposure scanning at this position. (This is an exposure process.)

  Thereafter, the surfaces of the photosensitive drums 5Y, 5M, 5C, and 5K reach a position facing the developing device 76, and the electrostatic latent image is developed at this position to form toner images of each color (developing process). .) Thereafter, the surfaces of the photoconductive drums 5Y, 5M, 5C, and 5K reach the positions facing the intermediate transfer belt 78 and the first transfer bias rollers 79Y, 79M, 79C, and 79K, and at these positions, the photoconductive drums 5Y, 5M. The toner images on 5C and 5K are transferred onto the intermediate transfer belt 78 (this is a primary transfer process). At this time, a small amount of untransferred toner remains on the photosensitive drums 5Y, 5M, 5C, and 5K.

  Thereafter, the surfaces of the photoconductive drums 5Y, 5M, 5C, and 5K reach a position facing the cleaning unit 77, and untransferred toner remaining on the photoconductive drums 5Y, 5M, 5C, and 5K is removed at this position. 77 is mechanically collected by a cleaning blade (cleaning process).

Finally, the surfaces of the photoconductive drums 5Y, 5M, 5C, and 5K reach a position facing a neutralization unit (not shown), and the residual potential on the photoconductive drums 5Y, 5M, 5C, and 5K is removed at this position. The
Thus, a series of image forming processes performed on the photosensitive drums 5Y, 5M, 5C, and 5K is completed.

  Thereafter, the toner images of the respective colors formed on the respective photosensitive drums through the developing process are transferred onto the intermediate transfer belt 78 in an overlapping manner. In this way, a color image is formed on the intermediate transfer belt 78.

  Here, the intermediate transfer unit 85 includes an intermediate transfer belt 78, four primary transfer bias rollers 79Y, 79M, 79C, and 79K, a secondary transfer backup roller 82, a cleaning backup roller 83, a tension roller 84, and an intermediate transfer cleaning unit 80. , Etc. The intermediate transfer belt 78 is stretched and supported by the three rollers 82 to 84 and is endlessly moved in the direction of the arrow in FIG.

  The four primary transfer bias rollers 79Y, 79M, 79C, and 79K respectively sandwich the intermediate transfer belt 78 between the photosensitive drums 5Y, 5M, 5C, and 5K to form a primary transfer nip. Then, a transfer bias reverse to the polarity of the toner is applied to the primary transfer bias rollers 79Y, 79M, 79C, and 79K. The intermediate transfer belt 78 travels in the direction of the arrow and sequentially passes through the primary transfer nips of the primary transfer bias rollers 79Y, 79M, 79C, and 79K. In this way, the toner images of the respective colors on the photosensitive drums 5Y, 5M, 5C, and 5K are primarily transferred while being superimposed on the intermediate transfer belt 78.

  Thereafter, the intermediate transfer belt 78 onto which the toner images of the respective colors are transferred in an overlapping manner reaches a position facing the secondary transfer roller 89. At this position, the secondary transfer backup roller 82 sandwiches the intermediate transfer belt 78 between the secondary transfer roller 89 and forms a secondary transfer nip. The four color toner images formed on the intermediate transfer belt 78 are transferred onto the recording medium P conveyed to the position of the secondary transfer nip.

  At this time, untransferred toner that has not been transferred to the recording medium P remains on the intermediate transfer belt 78. Thereafter, the intermediate transfer belt 78 reaches the position of the intermediate transfer cleaning unit 80. At this position, the untransferred toner on the intermediate transfer belt 78 is collected. Thus, a series of transfer processes performed on the intermediate transfer belt 78 is completed.

  Here, the recording medium P transported to the position of the secondary transfer nip is transported from the paper feeding unit 12 disposed below the apparatus main body 1 via the paper feeding roller 97 and the registration roller pair 98. It is a thing.

Specifically, a plurality of recording media P such as transfer paper are stored in the paper supply unit 12 in an overlapping manner. When the paper feed roller 97 is rotationally driven in the counterclockwise direction in FIG. 1, the uppermost recording medium P is fed between the rollers of the registration roller pair 98.

  The recording medium P conveyed to the registration roller pair 98 is temporarily stopped at the position of the roller nip of the registration roller pair 98 that has stopped rotating. Then, the registration roller pair 98 is rotationally driven in synchronization with the color image on the intermediate transfer belt 78, and the recording medium P is conveyed toward the secondary transfer nip. In this way, a desired color image is transferred onto the recording medium P.

  Thereafter, the recording medium P on which the color image is transferred at the position of the secondary transfer nip is conveyed to the position of the fixing device 20. At this position, the color image transferred on the surface is fixed on the recording medium P by heat and pressure generated by the fixing belt 21 and the pressure roller 31. Thereafter, the recording medium P is discharged out of the apparatus through a pair of paper discharge rollers 99. The recording medium P to be transferred discharged out of the apparatus by the discharge roller pair 99 is sequentially stacked on the stack unit 100 as an output image. Thus, a series of image forming processes in the image forming apparatus is completed.

Next, the protective agent coating apparatus according to the embodiment of the present invention will be described. Drawing 2 is a schematic diagram showing an example of composition of protective agent application device 20 of an embodiment.
The protective agent coating apparatus of the present invention comprises at least a roller-shaped protective agent supply member (protective agent supply roller, 22) having a cored bar and a foam layer on the outer periphery of the cored bar. ) Is supplied with a protective agent (image carrier protective agent, 21), and in the protective agent coating device (20) for applying the protective agent (21) to the surface of the image carrier (photosensitive drum 5). During a predetermined time during the initial driving after the replacement of the protective agent supply member (22), the protective agent (21) is supplied to the protective agent supply member (22), and the image carrier (22) is supplied from the protective agent supply member (22). It operates in the protective agent supply mode (M) in which the protective agent (21) is not applied to 5).

  In the present embodiment, the protective agent coating apparatus 20 includes a protective agent supply roller 22 having a foamed elastic layer disposed opposite to the photosensitive drum 5 as an image carrier, a pressing force applying mechanism 23, and image carrier protection. It is mainly composed of the agent 21. In FIG. 3, reference numeral 30 denotes a cleaning mechanism. Moreover, arrangement | positioning of the protective agent 21 is an example to the last, and is not restricted to this. In FIG. 1, the photosensitive drums are shown as 5Y, 5C, 5M, and 5K, but in the description of the protective agent coating apparatus 20, four types of photosensitive drums are shown as the photosensitive drums 5 for convenience.

  In this embodiment, the protective agent 21 contacts the protective agent supply roller 22 having the foamed elastic layer by the pressing force from the pressing force applying mechanism 23. At the time of image formation, the protective agent supply roller 22 having a foamed elastic layer rotates and rubs with the photosensitive drum 5 with a linear velocity difference. At this time, the protective agent 21 held on the surface of the protective agent supply roller 22 is replaced with The toner is supplied to the surface of the photosensitive drum 5. That is, the protective agent 21 is supplied from the protective agent 21 to the protective agent supply roller 22 and further supplied from there to the photosensitive drum 5.

  Here, the protective agent 21 includes boron nitride and also includes zinc stearate. By the protective agent using zinc stearate, the surface of the photosensitive drum 5 is covered relatively evenly, and good protection is provided from electrical stress in the charging process. In addition, a substance having a lamellar crystal has a layered structure in which amphiphilic molecules are self-organized, and when a shearing force is applied, the crystal is broken along the layers and easily slips. Therefore, the lubricity is excellent. Of these, fatty acid metal salts, particularly zinc stearate, are preferred in many electrophotographic apparatuses. Further, the protective agent 21 is a protective agent block formed in a bar shape, mixed with powder, poured into a mold, and compressed by a press to be solidified into a block shape.

  Moreover, as for the protective agent supply roller 22 of this embodiment, a foam layer shall contain a polyurethane foam. Still further, the foam layer contains an open-cell foam layer. Polyurethane foam can be manufactured at a relatively low cost, thus contributing to cost reduction of the unit. In addition, various manufactures have been established, and the surface shape of the outer shape can be configured relatively easily. Moreover, there is no influence of brush fall or deterioration, and the protective agent can be supplied in a constant amount over a long period. A solid lubricant film can be uniformly formed on the surface of the photosensitive drum with a relatively small consumption.

  Further, since it can be manufactured at a relatively low cost compared to a protective agent supply member such as a brush, it contributes to the cost reduction of the unit. Furthermore, since polyurethane has a small compression set and is difficult to deform, the deformation of the protective agent supply member can be prevented. In addition, by using an open-cell foam layer, the protective agent can be taken into not only the cells in the surface layer but also into the internal cells, which makes it possible to supply the protective agent more efficiently.

  As a method of manufacturing the protective agent supply roller 22 described above, a polyurethane foam that becomes an elastic layer is formed in advance from a polyurethane foam raw material into a block shape, cut into a required shape, polished on the surface, and a core material is inserted. Then, while rotating the polyurethane foam, apply a polishing blade and a grindstone to move the blade parallel to the axial direction and cut it to a specified thickness (traverse grinding), and a protective agent supply roller molding die containing a core metal There is a method of injecting polyurethane foam raw material into foam and curing it. Further, there is a method of cutting to a predetermined thickness after foaming with a roller mold, but the method is not limited to this.

  The polyurethane foam which is a foam can be manufactured by a conventionally known manufacturing method. As the polyurethane foam raw material, those added with auxiliary agents such as polyol, polyisocyanate, catalyst, foaming agent, foam stabilizer and the like are used. Usually, components other than the polyisocyanate are mixed in advance and mixed with the polyisocyanate component immediately before molding. In the present invention, the polyol component is preferably a polyol called a polyether polyol because it is easy to adjust processability, hardness of the polyurethane foam layer, etc., but is not limited thereto. As the polyether polyol, it can be appropriately selected from conventionally known various polyether polyols, but is not limited thereto.

  Moreover, what is necessary is just to select suitably from polyether polyether polyol, polyester polyether polyol, polymer polyether polyol etc. which are generally known as polyether polyol currently used for manufacture of a flexible polyurethane foam, and using 1 type or in combination of 2 or more types May be. In addition, when a polyether polyether polyol having 5 mol% or more of ethylene oxide bonded to a terminal is used, moldability is said to be good.

  Moreover, as polyisocyanate used for manufacture of the above-mentioned polyurethane foam layer, it can select and use suitably from conventionally well-known various polyisocyanate, for example, 2, 4- and 2, 6-tolylene diisocyanate ( TDI), tolidine diisocyanate (TODI), naphthylene diisocyanate (NDI), xylylene diisocyanate (XDI), 4,4'-diphenylmethane diisocyanate (MDI) and carbodiimide modified MDI, polymethylene polyphenyl polyisocyanate, polymeric polyisocyanate, etc. These may be used alone or in combination of two or more.

  Moreover, as a catalyst used for polyurethane foam layer manufacture, it can select and use suitably from the catalysts used for a conventionally well-known urethanation reaction, for example, a triethylenediamine, a dimethylethanolamine, bis (dimethylamino), for example. Examples include, but are not limited to, amine-based catalysts such as ethyl ether, organometallic catalysts such as dioctyltin and distearyltin dibutyrate, and modified catalysts thereof. It may be a reactive catalyst such as dimethylaminoethanol having active hydrogen in itself. By appropriately selecting a catalyst and controlling the amount used, the cell wall width, open cell diameter, hardness, air flow rate, etc. of the polyurethane foam layer can be adjusted.

  Furthermore, as a foam stabilizer used for the above-mentioned polyurethane foam layer production, any one can be used as long as it is used for polyurethane foam production, but a silicone surfactant is preferably used.

  Moreover, there is no restriction | limiting in particular as a foaming agent used for polyurethane foam layer manufacture, It is used individually or in combination of multiple types from conventionally well-known various foaming agents, such as water, a low boiling point thing, and a gas body. However, it is preferable to use water as a foaming agent from the viewpoint of the environment. Also, other foaming agents can be used in combination. By changing the use amount and conditions of the foaming agent, the cell wall width, cell diameter, hardness, air flow rate and the like of the polyurethane foam layer can be controlled.

  The polyurethane foam layer raw material may contain a crosslinking agent, a foam breaker and the like so as to control the closed cell property and open cell property of the cells of the polyurethane foam layer, and also to impart desired conductivity. A conductive agent, an antistatic agent, or the like may be added. Moreover, conventionally well-known things, such as a triethanolamine and a diethanolamine, are mentioned as a crosslinking agent. Other additives such as conductive agents, flame retardants, thickeners, pigments, stabilizers, colorants, anti-aging agents, UV absorbers, antioxidants, antioxidants, etc. Can be blended.

  The protective agent supply roller 22 of the present embodiment is not particularly limited in the number of cells and hardness of the foam layer as long as the object of the present invention is achieved, but the protective agent particles having a relatively small particle size and uniform are image-carrying. From the viewpoint of supplying to the body, the number of cells is preferably 20 to 300 cells / 25 mm, particularly 60 to 300 cells / 25 mm, and the hardness is preferably 40 to 430 N, particularly 40 to 300 N.

  Further, the particle size of the solid lubricant particles supplied to the surface of the photosensitive drum 5 can be controlled by adjusting the number of cells and the hardness of the foam layer. For example, when the number of cells is increased or the hardness is reduced, the particle diameter of the protective agent particle is reduced, but the force with which the roller 22 grinds the protective agent 21 is also reduced, and the amount of the protective agent is reduced.

  For the measurement of the number of cells in the foam layer, an average value of values measured by the following method is used. As shown in FIG. 3 (a), three measurement points are arbitrarily selected at both ends and the center in the axial direction on the surface of the foam layer (here, m1 and m2 in FIG. 3 (a) are selected). The measurement part at the end, m3 is the measurement part in the central part.) Next, two further points are selected in the circumferential direction at each measurement part to determine a total of nine measurement parts. Next, the photograph screen of each measurement location is observed using a microscope.

  Then, as shown in FIG. 3B, a line having a length corresponding to an actual size of 1 inch (about 25 mm) is drawn at the center of the photo screen, and the number of cells in the line is counted. Find the average value of points. A cell that touches even a 25 mm line is counted as one. For example, in the case as shown in FIG. 3B, the number of cells is 12. The hardness of the foam layer is an average value of values measured based on JIS K 6400 at arbitrary points on the surface of the foam layer.

  Next, the core metal in the protective layer supply roller 22 can be formed of, for example, a cylindrical body made of a metal such as iron, aluminum, or stainless steel or a non-metal such as resin, but is not limited thereto. In addition, an adhesive layer may be provided on the core bar in advance. Further, in the manufacturing method using the molding die of the protective agent supply roller containing the cored bar described above, it is preferable to provide a release layer such as a fluororesin coating agent or a release agent on the inner surface of the molding die. A polyurethane foam layer having suitable openability can be easily formed without requiring complicated processing.

  Next, an example of the operation of the photosensitive drum 5 and the protective agent supply roller 22 during image formation will be described with reference to FIG. At the time of image formation, the photosensitive drum 5 rotates at the linear velocity V1 mm / sec, and the protective agent supply roller 22 rotates at the linear velocity V2 mm / sec in the same direction of the arrow. Since the respective rotations are in the same direction (forward direction, counter direction), the linear velocity difference is generated at V1 + V2 mm / sec, and the protective agent 21 is applied to the photosensitive drum at the nip portion N due to the friction between the two due to the linear velocity difference. 5 is supplied. In this embodiment, V1 rotates at 200 mm / sec, V2 rotates at 150 mm / sec, and the linear velocity difference is 350 mm / sec.

  Next, another example of the operations of the photosensitive drum 5 and the protective agent supply roller 22 during image formation will be described with reference to FIG. At the time of image formation, the photosensitive drum 5 and the protective agent supply roller 22 rotate in opposite directions (trailing direction) as indicated by arrows. For this reason, the photosensitive drum 5 and the protective agent supply roller 22 are rubbed by the linear velocity difference | V1−V3 |, and the protective agent is supplied to the photosensitive drum at the nip portion N. In this embodiment, V1 rotates at 200 mm / sec, V3 rotates at 300 mm / sec, and the linear velocity difference is 100 mm / sec.

  Next, the protective agent supply mode (M) of the protective agent coating apparatus 20 will be described in detail with reference to FIGS. FIG. 6 is a graph showing the relationship between the travel distance of the image carrier and the driving torque during the operation of the protective agent coating apparatus according to the embodiment.

  Here, as already described, the protective agent supply mode refers to the protective agent application device 20 at a predetermined time during the initial drive after the replacement of the protective agent supply member (protective agent supply roller) 22. 21 is supplied to a protective agent supply roller (protective agent supply member) 22 and performs an operation in which the protective agent 21 is not applied to the photosensitive drum (image carrier) 5 from the protective agent supply roller 22. That is, before performing the operation of “applying the protective agent 21 to the photosensitive drum 5 at the time of image forming operation” (the operation at the time of image formation in FIG. 6), which is the original operation of the protective agent coating apparatus 20. It refers to performing the operation of applying the protective agent 21 only to the agent supply roller 22 (protective agent supply mode, M in FIG. 6).

  In this way, by performing the operation of applying the protective agent 21 to the protective agent supply roller 22 before the operation of applying the protective agent 21 to the photosensitive drum 5, the surface resistance of the roller 22 (the friction coefficient of the surface of the roller 22). ) Goes down. This eliminates the need for a large driving torque (maximum torque max1 in FIG. 11) for driving a new protective agent coating apparatus as in the prior art. Then, assuming the maximum value of the driving torque necessary for applying the protective agent 21 (maximum torque max2 in FIG. 6), the protective agent applying device 20 is driven only by setting the motor driving torque to this magnitude. Can be made. For this reason, it is not necessary to prepare a high-spec motor only for a new product, and the cost can be reduced.

  FIG. 7 is a schematic diagram for explaining the operation in the protective agent supply mode of the first embodiment. When a new protective agent coating device 20 is used, when the protective agent supply member (roller 22) and the image carrier (photosensitive drum 5) are driven by different driving means, in the protective agent supply mode M, the roller The photosensitive drum 22 and the photosensitive drum 5 are rotationally driven at the same linear speed and in the same direction. Here, the photosensitive drum 5 and the protective agent supply roller 22 are individually driven by a motor or the like (not shown) and rotated in the direction of the arrow at the same linear speed V1, and therefore the photosensitive drum 5 and the protective agent supply roller 22 are driven. And the surface does not rub.

  Therefore, the driving torque of the photosensitive drum 5 and the protective agent supply roller 22 can be smaller than that at the time of image formation shown in FIGS. As shown in FIG. 6, the driving torque in the protective agent supply mode M is relatively small compared to the driving torque at the time of image formation.

  At this time, it is possible to set the rotation speed and the rotation direction when the protective agent supply roller 22 is driven by a driving means such as a motor. Therefore, it is possible to execute the operation in the protective agent supply mode regardless of the operation conditions during image formation.

  In the present embodiment, V1 is set to 200 mm / sec. At this linear speed, the protective agent supply roller 22 scrapes the protective agent 21, and the protective agent 21 is supplied to the surface of the roller 22 and a cell (not shown) of the roller 22. The friction coefficient of the roller surface is reduced. At this time, since there is no sliding friction with the photosensitive drum 5, the protective agent 21 is hardly supplied to the photosensitive drum 5, and the main supply of the protective agent 21 is as described above. This is performed at the time when the sliding of both occurs, such as at the time of adjusting the image density.

  Next, an operation example in the protective agent supply mode of the second embodiment will be described with reference to FIG. Similar to the operation in the protective agent supply mode of the first embodiment, the protective agent supply roller 22 and the photosensitive drum 5 are driven by different driving means. At this time, a contact / separation means (not shown) for holding the roller 22 in contact or non-contact with the photosensitive drum 5 is further provided. In the protective agent supply mode, the roller 22 is separated from the photosensitive drum 5. Only the driving means (motor (not shown)) of the roller 22 is driven at a linear velocity V4 mm / sec while being held in a non-contact state.

  The contact / separation means selects a suitable member that satisfies the above-described configuration. For example, a member used for preventing deformation of the foam layer of the roller 22 can be used. In the case of the protective agent coating apparatus having such a configuration, the protective agent supply mode can be performed by driving the roller 22 in a state where the roller 22 is separated from the photosensitive drum 5, and the photosensitive drum 5 itself is moved. There is no need to drive. In this case, since the linear velocity of the roller 22 can be set freely, the protective agent supply mode can be completed in a shorter time than the configuration of FIG.

  Next, an example of operation in the protective agent supply mode of the third embodiment will be described with reference to FIG. Unlike the protective agent supply modes of the first and second embodiments, the roller 22 and the photosensitive drum 5 are driven by the same driving means. At this time, in the protective agent supply mode, the roller 22 rotates in conjunction with the rotation of the photosensitive drum 5 by the driving means. Therefore, here, when the photosensitive drum 5 is driven at a linear velocity V1 mm / sec, the roller 22 also rotates at the linear velocity V1 mm / sec in conjunction with the rotation of the photosensitive drum 5. In the third embodiment, the protective agent supply roller drive gear 32 is driven from the photosensitive drum drive gear 34 via the idler gear 36 during image formation. According to this configuration, the linear speed ratio between the photosensitive drum 5 and the roller 22 cannot be changed, but the driving torque can be suppressed, so that further cost reduction can be desired.

  In the operation example of the protective agent supply mode of the third embodiment, the roller 22 is moved to the moving position 36a by removing the idler gear 36 when the roller 22 is installed in the image forming apparatus 1, for example. Since it rotates with the body drum 5, the same effect as that in the operation of the first embodiment shown in FIG. 7 can be obtained. In the third embodiment, the idler gear 36 is moved to the moving position 36a by using a gear swing mechanism (not shown), and returns to the original position when the protective agent supply mode ends.

  Here, in the first to third embodiments shown in FIGS. 7 to 9, the protective agent coating device 20 including the new protective agent supply roller 22 (unused state at the time of replacement) is put into the image forming apparatus 1. Then, the protective agent supply mode M (FIG. 6) is performed without performing the conventional image forming operation for a predetermined time during the initial driving. For example, the following method is used to detect that the protective agent supply roller 22 is new.

  First, a replacement agent for the protective agent coating apparatus, such as a user or a service person, inputs new product information to the image forming apparatus 1. Specifically, for example, information indicating that the protective agent coating apparatus 20 is new is input to a control unit having a function of comprehensively controlling the operation of the image forming apparatus 1. Alternatively, as described later, when the driving torque for the image forming operation on the photosensitive drum 5 requires a certain value or more, it is determined that the protective agent coating device 20 including the protective agent supply roller 22 is new.

The predetermined time during the above-described initial drive is from the time of new article (when unused replacement) to the point A in FIG. 1B, and is 30 sec (seconds) in the present embodiment.
The operation time of the protective agent supply mode M (time to point A shown in FIG. 1) is not always constant and may vary depending on the environment or the like. When the constant is set, the fluctuation must be taken into consideration and set to a value with a margin. If the time during which the drive torque is stabilized is shorter than the set time, the operation becomes useless. In order to avoid this, for example, a torque limiter may be provided in the motor that drives the roller 22.

  FIG. 10 is a flowchart of the operation according to the protective agent supply mode when a torque limiter is provided. When the protective agent supply roller 22 is replaced (when the protective agent applicator 20 is replaced), it is detected by a variety of suitable methods (ST1). Next, the protective agent coating apparatus 20 performs the operation in the protective agent supply mode for 5 seconds (ST2). Thereafter, the protective agent coating apparatus 20 once performs an image forming operation (ST3). Here, when the supply of the protective agent 21 is insufficient, the surface resistance of the roller 22 (coefficient of friction on the surface of the roller 22) is not sufficiently small, so that the driving torque at the time of image formation is assumed in FIG. It cannot be operated at the maximum torque (max2). Thus, the torque limiter is set so that the motor does not rotate under this condition. By performing such a setting, when the motor rotates, the operation of the protective agent supply mode ends at that time (ST4). On the other hand, when the motor does not rotate, the operation of the protective agent supply mode is performed again ( ST2) The above operation is repeated until the motor rotates, and the process ends when the motor rotates (ST4). Thus, the operation of the protective agent supply mode can be completed in the minimum necessary time.

  The roller 22 of the protective agent coating device 20 is not replaced as a single item. For example, if the process cartridge including the protective agent coating device 20 and the photosensitive drum 5 is replaced in units of cartridges, the replacement work is easy. In this case, for example, a new article detection unit (not shown) of the image forming apparatus 1 performs new article detection when the process cartridge is replaced. Various suitable new article detecting means are selected. At this time, the operation related to the protective agent supply mode is performed at the same time as the operation adjustment of other units such as the developing unit, so there is no concern that the user may cause downtime due to the operation in the protective agent supply mode.

  In the case of the process cartridge using the above-described protective agent coating apparatus 20 and the image forming apparatus including the above-described protective agent coating apparatus 20 or the process cartridge, a high-spec motor is used only when the protective agent coating apparatus is new. Therefore, it is possible to obtain a process cartridge and an image forming apparatus that can reduce costs. Further, the TEC (Typical Electricity Consumption) value of the image forming apparatus can be reduced by the image forming apparatus provided with the protective agent coating apparatus or the process cartridge of the present invention.

  The above-described embodiment is a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the gist of the present invention. For example, the rotation direction and linear velocity of the roller 22 at the time of image formation are not particularly limited, and the conditions are set such that the protective agent 21 can be supplied most efficiently. Further, this condition is not necessarily fixed when the driving means for the photosensitive drum 5 and the roller 22 are different (Embodiments 1 and 2 relating to the operation in the protective agent supply mode). Or the like, the image conditions such as the image area ratio, and the time-dependent conditions such as the number of sheets to be passed may be sequentially changed.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 3 Exposure part 4Y, 4M, 4C, 4K Image creation part 5Y, 5M, 5C, 5K Photosensitive drum (image carrier)
12 Paper Feeding Unit 20 Protective Agent Application Device 21
22 Protective agent supply roller (roller, protective agent supply member)
23 Pressing force applying mechanism 30 Cleaning mechanism 32 Protective agent supply roller driving gear 34 Photosensitive drum driving gear 36 Idler gear 36a Moving position 75 Charging unit 76 Developing unit 77 Cleaning unit 78 Intermediate transfer belt 79 Primary transfer bias roller 80 Intermediate transfer cleaning unit 82 Secondary transfer backup roller 83 Cleaning backup roller 84 Tension roller 85 Intermediate transfer unit 89 Secondary transfer roller 97 Paper feed roller 98 Registration roller pair 99 Paper discharge roller pair 100 Stack unit 101 Bottle storage unit 102 Toner bottle M Protection agent supply mode N Nip part p Recording medium

JP 2009-150986 A JP 2012-118307 A JP 2009-98555 A

Claims (10)

A roller-shaped protective agent supply member having a cored bar and a foam layer on the outer periphery of the cored bar is provided. The protective agent supply member receives supply of the protective agent, and the protective agent is supplied to the image carrier. In the protective agent application device applied to the surface,
In a predetermined time at the time of initial driving after replacement of the protective agent supply member, the protective agent is supplied to the protective agent supply member,
The protective agent coating apparatus operates in a protective agent supply mode in which the protective agent is not applied to the image carrier from the protective agent supply member.   The protective agent supply member is driven by the same drive means as the image carrier or a different drive means, and the drive means can set the number of rotations and the direction in which the protective agent supply member is driven. The protective agent coating apparatus according to claim 1. The protective agent supply member is driven by a driving means different from the image carrier,
3. The protective agent coating apparatus according to claim 1, wherein in the protective agent supply mode, the protective agent supply member and the image carrier are driven to rotate in the same linear speed and in the same direction. . A contact / separation means for holding the protective agent supply member in contact or non-contact with the image carrier;
The protective agent supply member is driven by a driving means different from the image carrier,
3. The protection agent supply mode according to claim 1, wherein in the protection agent supply mode, the protection agent supply member is separated from the image carrier by the contact / separation unit and is driven by the driving unit in a non-contact state. Protective agent applicator. The protective agent supply member is driven by the same driving means as the image carrier,
3. The protective agent coating apparatus according to claim 1, wherein in the protective agent supply mode, the protective agent supply member rotates in conjunction with rotation by a driving unit of the image carrier.   The said foam layer contains foaming polyurethane, The protective agent coating device of any one of Claims 1-5 characterized by the above-mentioned.   The said foam layer contains an open cell type foam layer, The protective agent coating device of any one of Claims 1-5 characterized by the above-mentioned.   The protective agent coating apparatus according to any one of claims 1 to 7, wherein the protective agent contains a fatty acid metal salt and an inorganic lubricant.   9. A process cartridge comprising: the protective agent coating apparatus according to claim 1; and a rotating image carrier that applies the protective agent.   An image forming apparatus comprising the protective agent coating device according to claim 1 or the process cartridge according to claim 9.