JP2006259274A - Image forming apparatus and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus and a process cartridge for the image forming apparatus that can stabilize the amount of a lubricating agent supplied to an image carrier without varying it. <P>SOLUTION: In an electrophotographic image forming apparatus A which has the image carrier 1 and is provided with a cleaning device 2 cleaning the image carrier 1, the cleaning device 2 has at least a member 4 which rotates in contact with the image carrier 1, a solid lubricating agent 5 which contacts the rotary member 4, and a pressure member 6 which presses the lubricating agent 5 against the rotary member 4, and the pressure member 6 is so constituted that a pressing force applied to the lubricating agent 5 is always a nearly constant pressing force within a use range of the lubricating agent 5, thereby making the amount of the supplied lubricating agent 5 constant. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile machine or the like.

  In general, in an electrophotographic image forming apparatus, various methods such as a cleaning blade method and a fur brush method have been proposed and used as means for cleaning an image carrier. In these various cleaning methods, a structure for supplying a lubricity-imparting agent to the image carrier has been proposed in order to ensure the cleaning property.

  In this configuration, a lubricity-imparting agent is supplied via a member in contact with the image carrier, and a configuration in which the lubricity-imparting agent is pressed against the member is frequently used.

  However, in the above-described conventional configuration, the amount of pressurization changes with the consumption of the lubricity imparting agent, the amount of the lubricity imparting agent supplied to the image carrier fluctuates, and the supply amount cannot be sufficiently stabilized. There was a problem.

  SUMMARY OF THE INVENTION Accordingly, the present invention solves the problems of the conventional devices as described above, and is an image forming apparatus and an image forming apparatus that can be stabilized with a simple configuration without changing the supply amount of the lubricity-imparting agent to the image carrier. An object of the present invention is to provide a process cartridge.

  In order to solve the above problems, the invention described in claim 1 is an electrophotographic image forming apparatus having an image carrier and provided with a cleaning device for cleaning the image carrier. At least a member that rotates in contact with the image carrier, a solid lubricity imparting agent that contacts the rotating member, and a pressing member that presses the lubricity imparting agent on the rotating member side. The pressing force supplied to the lubricity-imparting agent is configured so that the pressing force is always substantially constant within the usage range of the lubricity-imparting agent, and the supply amount of the lubricity-imparting agent is made constant.

  According to a second aspect of the present invention, in the first aspect, the lubricity-imparting agent is provided with a sheet metal that reinforces the lubricity-imparting agent, and the pressing member does not use a fastening member. It is attached.

  According to a third aspect of the present invention, in the first or second aspect, at least two types of springs having different spring constants are used as the pressing member.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the spring is integrally formed with the sheet metal.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the lubricity imparting agent is zinc stearate.

  According to a sixth aspect of the present invention, an image carrier and at least a cleaning device are integrated into a single case, and the cleaning device includes at least a member that rotates in contact with the image carrier. A solid lubricity imparting agent in contact with the rotating member, and a pressing member that presses the lubricity imparting agent on the rotating member side, and the pressing member supplies a pressing force to the lubricity imparting agent. In the usage range of the lubricity-imparting agent, it is configured so that the pressing force is always almost constant, the supply amount of the lubricity-imparting agent is constant, and the integrated component is detachable from the apparatus main body. .

  Since the present invention is configured as described above, the supply amount of the lubricity-imparting agent to the image bearing member can be stabilized without fluctuation with a simple configuration.

  First, the problems to be solved by the image forming apparatus according to the present invention are as described above, but further supplemented are as follows. That is, an electrophotographic image forming apparatus has a photoconductor as an image carrier, and this photoconductor is driven in a predetermined manner so that the surface of the photoconductor is sequentially in the vicinity of some predetermined locations outside the photoconductor. In this moving process, a series of processes are sequentially performed to generate an image on the surface, and the image is transferred to a transfer material to be imaged. After the transfer, the surface of the photoconductor is cleaned, and as a method for removing the transfer residual toner attached to the surface of the photoconductor as the cleaning, an elastically deformable blade member such as urethane rubber is used. There are employed a method in which the blade edge is pressed against the photosensitive member and scraped off, or a method in which a bristle brush such as a fur brush is brought into contact with the photosensitive member.

  However, when fine toner, toner melted by heat, pressure, or the like adheres to the photoconductor, the transfer residual toner cannot be completely removed with the blade alone, and a filming layer is gradually formed on the surface of the photoconductor. For this reason, the coefficient of friction on the surface of the photoconductor increases, and the frictional force generated between the blade edge and the surface of the photoconductor in contact with the edge increases, and there is a problem that the blade is likely to be caught in the photoconductor.

  Therefore, this problem has been addressed by supplying a lubricant imparting agent to the surface of the photoreceptor. That is, a lubricity imparting agent is applied to the surface of the photoconductor to suppress an increase in the coefficient of friction on the surface and prevent the blade from being caught in the photoconductor. Therefore, it has been desired that the supply amount of the lubricity-imparting agent to the photoreceptor is stable.

  The following method has been proposed and used as a method for stably supplying this lubricity-imparting agent to the photoreceptor.

  That is, a method of supplying a lubricity imparting agent shaved off by a dedicated member to a photoreceptor by an application member (see JP-A-9-81005) or a lubricity imparting agent having a predetermined two-layer structure and applying stably. A method (see Japanese Patent Laid-Open No. 2000-338819) has been proposed.

  In the former method, a grinding roller is interposed between the existing application member and the lubricity imparting agent, the lubricity imparting agent is scraped off by this grinding roller, and the scraped lubricity imparting agent is removed from the grinding roller. It is transferred to the coating member and supplied to the photoreceptor by the coating member.

  In the latter method, the lubricity imparting agent has a two-layer structure in which an upper layer to be shaved first and a lower layer to be shaved after the upper layer is shaved are integrally formed. While the lower layer is formed of a machinable agent material, the lower layer is formed of a difficult-to-cut agent material that is harder to cut to a predetermined degree than the upper layer. For this reason, with the latter method, even when the contact area of the lubricity-imparting agent itself with the application member is small immediately after the use of a new lubricity-imparting agent, the upper layer can be easily scraped, so that a sufficient application amount can be secured. At the same time, when the contact area is increased, a lower layer that is difficult to scrape appears, so that the application amount can be prevented from being excessive, and a stable application amount can be secured.

  However, in the former method in which the lubricity-imparting agent is scraped off by the grinding roller, the lubricity-imparting agent shaved by the grinding roller is transferred to an existing application member such as a fur brush and applied to the photoconductor. Since a new grinding roller for the member is required, the cost is increased, and an installation space for another member is required, which is disadvantageous in terms of space. Further, there is a problem that the pressure of the spring changes with the wear of the lubricity imparting agent, and the amount of the lubricity imparting agent applied cannot be made sufficiently constant. That is, in this configuration, a compressed spring is disposed on the back side of the lubricity-imparting agent relative to the grinding roller so that the grinding portion of the lubricity-imparting agent is in contact with the grinding roller at all times. The lubricity imparting agent is pressed against the grinding roller by force. Accordingly, the size of the lubricity-imparting agent located between the grinding roller and the spring is reduced along with the scraping, and the spring is extended. For this reason, the pressing force applied to the lubricity-imparting agent from the spring decreases, and the amount of scraping by the grinding roller decreases. As a result, the coating amount decreases and fluctuates and cannot be made constant.

  On the other hand, in the latter method in which the lubricity-imparting agent has a two-layer structure and the application is stabilized, the lubricity-imparting agent has a two-layer structure having different grinding characteristics, so that the structure of the lubricity-imparting agent itself is complicated. This will increase costs. Further, there is a problem that the pressure of the spring changes with the wear of the lubricity imparting agent, and the amount of the lubricity imparting agent applied cannot be made constant. That is, a compressed spring is arranged behind the lubricant imparting agent facing the application member so that the lubricant imparting agent is always in contact with the application member, and the lubricant imparting agent is applied by the elastic restoring force of this spring. Since the pressure is applied to the member side, the coating amount fluctuates and cannot be made constant for the same reason as in the former method.

  Therefore, the present invention provides an image forming apparatus that has a simple configuration, does not increase the consumption space, and can make the supply amount of the lubricity imparting agent to the surface of the photoreceptor constant.

That is, in this invention, the lubricity imparting agent is ground by using a fur brush that is an existing cleaning member, instead of newly providing a roller for scraping the lubricity imparting agent. Moreover, the lubricity imparting agent has a single-layer structure without using a two-layer structure.
And in order to make supply_amount | feed_rate of a lubricity imparting agent constant, it is calculated | required that the pressing force of the lubricity imparting agent with respect to a fur brush is made constant. That is, it is desirable that the pressure for pressing the lubricity imparting agent toward the fur brush is always constant regardless of the consumption amount of the lubricity imparting agent.
Therefore, two or more pressing members having different characteristics, that is, at least two types of springs having different spring constants are used as members for pressing the lubricity imparting agent on the application member side, and the lubricity imparting agent can be scraped off. It was set so that the pressing force changing depending on the condition could be kept constant. That is, the change in the pressing force obtained from the two types of springs is configured to be as small as possible even when the spring is extended as the lubricity imparting agent is shaved and becomes smaller.
Note that the two types of springs can be integrated or separated, and which one to select is determined in consideration of cost and assembly. That is, two types of springs may be integrally formed on a sheet metal disposed on the back side of the lubricity imparting agent, or may be provided separately.

Next, the present invention will be described using specific embodiments.
FIG. 1 schematically shows a cross-sectional view of the main part of an image forming apparatus to which an embodiment of the present invention is applied. In the image forming apparatus A in FIG. 1, 1 is a photosensitive drum as an image carrier, 2 is a cleaning device for cleaning the surface of the photosensitive drum 1, 3 is a cleaning blade as one cleaning member of the cleaning device 2, 4 is a fur brush which is the other cleaning member of the cleaning device 2, 5 is a coating bar which is a lubricity imparting agent, 6 is a coating bar pressing spring (hereinafter referred to as a pressing spring) which is a pressing member, and 7 is waste toner. A conveying coil, 8 is a charging roller as a charging device, 9 is a cleaning roller for cleaning the charging roller, and 100 is a process cartridge having an integrated structure in which these members and devices are housed in a case. The cartridge 100 is installed in the main body of the image forming apparatus. Obtained has easily detachable from the predetermined position, and to allow new replacement collectively member and devices housed in the cartridge 100.

  That is, in this embodiment, the photosensitive drum 1, the cleaning device 2 that cleans the photosensitive drum 1 in a predetermined manner, and at least the charging roller 8 that is a charging device that charges the photosensitive drum 1 are in the predetermined range. The process cartridge 100 is housed in a single case and unitized. The process cartridge 100 is configured to be easily detachable from a predetermined position in the image forming apparatus main body (not shown) of the image forming apparatus A. ing.

  The photosensitive drum 1 is rotatably supported by a bearing member (not shown) in the case, and the photosensitive drum 1 is driven by a driving motor (not shown) provided on the image forming apparatus main body side as a driving source with respect to the rotating shaft. Thus, the photosensitive drum 1 is stably rotated at a predetermined constant rotational speed in the clockwise direction in the figure. Around the photosensitive drum 1, from the upstream side to the downstream side in the rotation direction, a static elimination lamp (not shown) as a static elimination device, a charging roller 8, a developing unit (not shown) as a developing device, and a cleaning device 2 Are arranged sequentially. Accordingly, with the rotation of the photosensitive drum 1, predetermined portions on the outer peripheral surface of the photosensitive drum 1 are the discharging positions and charging positions formed by the discharging lamp, the charging roller 8, the developing device, and the cleaning device 2, respectively. Then, the developing position and the cleaning position are sequentially passed, and again returned to the charge removal position. Further, an exposure position is provided between the charging position and the developing position by an exposure device (not shown), and a position where the outer peripheral surface of the photosensitive drum 1 is in contact with the sheet conveying means 101 between the developing position and the cleaning position. Each transfer position is set.

  As described above, in the image forming apparatus A, the photosensitive drum 1 is rotated, and along with the rotation, predetermined portions on the outer peripheral surface of the photosensitive drum 1 are sequentially passed through the respective positions, and the respective positions are set. A series of image forming processes including static elimination, charging, exposure, development, transfer, and cleaning are performed on one transfer material, and are repeated for each transfer material.

  The neutralization lamp is a neutralization light source for neutralizing residual charges on the surface of the photoreceptor 2 from which the residual toner has been removed by the cleaning device 2, and the neutralization lamp ensures a predetermined intensity of light for neutralization and a predetermined amount of light. A structure that irradiates the static elimination position, for example, a structure of an LED array in which a plurality of LEDs (light emitting diodes) are arranged in a straight line, and is arranged along the axial direction (main scanning direction) of the photoreceptor 2. ing.

  The charging roller charges the surface of the photosensitive drum 1 to a predetermined level by a charging roller as a charging member. That is, the charging roller 8 is either provided with its surface in contact with the surface of the photosensitive drum 1 or non-contact with the surface, and at least the surface of the roller is not shown. A charging voltage controlled to a predetermined value is applied from the charging voltage applying means, whereby the surface of the photosensitive drum 1 passing through the charging position is uniformly charged.

That is, in the former configuration provided in contact with the charging roller 8, the charging roller 8 is rotated by the rotation of the photosensitive drum 1, or is rotated in the reverse direction so as to be driven. It enables a uniform charge on the surface.
On the other hand, in the latter configuration in which the charging roller 8 is provided in a non-contact manner, the roller surface of the charging roller 8 is a non-contact but electromagnetic action with respect to the surface of the photosensitive drum 1 rotated counterclockwise. Are provided so as to be opposed to each other with a predetermined minute interval (gap) that can sufficiently exert the above. The charging roller 8 is driven to rotate in a direction opposite to that of the photosensitive drum 1, and enables uniform charge on the surface of the photosensitive drum 1.

  Further, on the upper side of the charging roller 8, a cleaning roller 9 is installed as a cleaning member for the charging member that is pivotally supported in a state of being in constant contact with the charging roller 8. Is cleaning.

  At the exposure position, a laser beam L is scanned and irradiated from an exposure device provided on the image forming apparatus main body side to form an electrostatic latent image on the surface of the photosensitive drum 1 that occupies the exposure position. I am doing so.

  The developing device has, for example, a developing sleeve having an outer shape of a roller whose surface is rotated so as to be driven by the photosensitive drum 1 by providing a predetermined minute interval on the surface of the photosensitive drum 1, and a toner brush on the developing sleeve. The toner particles move from the formed brush-like toner to the electrostatic latent image on the surface of the photosensitive drum 1. That is, an appropriate size is provided between the exposed portion and the non-exposed portion of the photosensitive drum 1 by a configuration in which a ferromagnetic material such as a magnet is disposed inside the developing sleeve, or from a voltage application mechanism (not shown) to the developing sleeve. Magnetic brush having a configuration in which a large number of electromagnetic or electrical lines of force project radially from the surface of the developing sleeve and uniformly on the outer peripheral surface thereof, by applying a developing bias in which a voltage of the same length or an alternating voltage is applied thereto. And the toner is arranged along the magnetic brush. In such a brush-like toner formed by a magnetic action, only the toner particles are attracted to the electrostatic latent image by an electrostatic action. Therefore, the electrostatic latent image generated on the surface of the photosensitive drum 1 is visualized as a toner image by the developing device.

  A transfer position is set between the development position and the cleaning position, that is, a position on the photosensitive drum 1 that is an outer peripheral portion substantially diagonally to the left of the center of the drum in the figure. A transfer nip formed on the outer peripheral surface of the body drum 1 in contact with, for example, a sheet conveying unit 101 constituted by a traveling belt is provided, and the traveling belt of the sheet conveying unit 101 has a traveling surface facing diagonally upward to the left. A toner image formed on the outer peripheral surface of the photosensitive drum 1 is transferred onto a sheet (not shown), which is a transfer material that is secured and transported by a predetermined belt and is transported by being placed on the upper surface of the traveling belt. In this case, they are brought into contact with each other at almost the same speed synchronized with each other and transferred to the paper side. That is, the running belt as the main part of the paper conveying means 101 shown in FIG. 1 is belt-driven at a constant speed in one direction diagonally upward to the left in the figure, and is applied to the belt surface on the photosensitive drum 1 side. Then, the paper is placed and conveyed at a constant speed in the above-described direction. Further, on the outer periphery at the transfer position, a transfer roller or the like is provided so as to face the paper conveying means 101 via the traveling belt, and the transfer belt is supported from the inner peripheral side to stabilize the transfer nip, A transfer bias having a reverse polarity (for example, a positive polarity) to that of the toner is applied to the transfer roller to ensure transfer at the transfer nip.

  The cleaning device 2 removes the toner remaining on the surface of the photosensitive drum 1 after passing through the transfer position and cleans it. The cleaning device 2 is fixedly installed as the toner removing means and fixed on the photosensitive drum 1. A cleaning blade 7 that slides relative to the photosensitive drum 1, and a fur brush 8 that rotates following the photosensitive drum 1 upstream of the cleaning blade 7 in the rotational direction of the photosensitive drum 1. Has been.

  The cleaning blade 7 is formed in a long plate-like elastic body using a synthetic rubber material such as urethane rubber, and the tip of the blade body secures a predetermined angle and a predetermined pressure with respect to the outer peripheral surface of the photosensitive drum 1. The position where the tip of the blade is in contact is set as a cleaning position, and the residual toner carried by the blade tip attached to the outer peripheral surface is dammed and scraped off from the surface. That is, the cleaning blade 7 has a blade edge at the tip thereof having a predetermined pressure and a predetermined contact angle at a predetermined position on the outer peripheral surface of the photosensitive drum 1, and the shaft of the photosensitive drum 1 as the position. The toner is uniformly contacted over a predetermined range in the longitudinal direction, and the toner remaining on the surface and carried along with the rotation of the photosensitive drum 1 is removed by the cleaning blade 7 being scraped off from the surface. Like to do.

  More specifically, the cleaning blade 7 is a toner that is a developer remaining on the surface of the photosensitive drum 1 with the tip end on the photosensitive drum 1 side being in contact with the outer peripheral surface of the photosensitive drum 1 after the transfer. Has a blade material which is a plate-like rubber member as a main body of the cleaning blade 7 which is dammed and scraped off, and this blade material is integrally joined to a support substrate whose base end is a long plate-like metal plate. The blade chip is configured as a blade chip, and the base end of the blade chip is sandwiched by a holder and is held in place, and the holder is a support plate that supports a support substrate as the base end of the blade chip. And a pressing plate that presses the support substrate toward the support plate.

  Further, the base end of the support plate of the holder is pivotally supported on a shaft arranged in parallel with the rotation axis of the photosensitive drum 1, and the base end of the pressing plate is a coil spring or the like as a driving source for pressing bias. Is connected to one end of the elastic member. That is, the elastic member is compressed and installed, the other end is a fixed end fixed in contact with the case, and the one end in contact with the base end of the pressing plate is a free end. Therefore, with this elastic member, the leading end portion of the blade material as the cleaning blade 7 facing the photosensitive drum 1 side sets predetermined conditions on the outer peripheral surface of the photosensitive drum 1 after the transfer as described above. So that the holder is pressed in a predetermined direction.

  The fur brush 4 includes a brush shaft 4a having a predetermined diameter and brush bristles 4b planted on the brush shaft 4a. The fur brush 4 is rotationally driven in a predetermined manner so as to run backward with respect to the photoreceptor 1. Yes. That is, the brush shaft 4a ensures at least an axial length equal to or longer than the length in the longitudinal direction of the photosensitive drum 1, the central axis thereof is parallel to the rotational axis of the photosensitive drum 1, and the brush bristles 4b. The front end of the photosensitive drum 1 is pivotally supported on the case side so as to be rotatable with an inter-axis distance secured so as to be in contact with a predetermined outer peripheral surface of the photosensitive drum 1. The brush bristles 4b are made of elastic bristles each having a predetermined length and a small diameter, which are radiated in the radial direction of the brush shaft 4a and uniformly in the longitudinal direction of the shaft. It is assumed to be a planted configuration. Further, when the photosensitive drum 1 rotates, the fur brush 4 receives a rotational driving force from a driving source (not shown) in association with the rotation of the photosensitive drum 1 when the photosensitive drum 1 rotates. It is configured to be driven to rotate at a predetermined speed so as to accompany it.

  Accordingly, the fur brush 4 driven to rotate in the reverse direction as described above uses the position where the brush bristles 4b are in contact as a preliminary cleaning position, and the outer peripheral surface of the photosensitive drum 1 after the transfer is the cleaning blade 7 along with the rotation. The outer peripheral surface is preliminarily cleaned before reaching the surface of the cleaning device 2, and the cleaning blade 7 receives and scoops off the falling toner, and scoops up the inner surface of the cleaning device 2 away from the photosensitive drum 1. Carry away to the back.

  The waste toner carrying coil 7 forms the start end of the carrying path as the collected toner carrying means at the inner back. That is, the waste toner transport coil 7 is a spiral coil-shaped shaft member, the start end of which is disposed at the bottom of the inner back portion, and the transport path (not shown) and the end of the transport path are image forming. Connected to either the recovery unit provided on the apparatus main body side or the developing device and driven to rotate in a predetermined manner, the recovery unit or the developing device located at the end in the direction in which the spiral advances with this rotation In either case, the toner collected in the cleaning device 2 is transported.

  The coating bar 5 is disposed above the fur brush 4 shown in FIG. 1, and the lower end, which is the front surface side facing the fur brush 4, is always the upper part of the rotating outer peripheral surface of the fur brush 4. The upper end, which is the back side that does not face, is pressed in the direction toward the fur brush 4 by pressing springs 6A and 6B as two types of pressing members that constitute the pressing member 6, The springs 6A and 6B are configured in a predetermined manner, and the pressing force supplied from both the pressing springs 6A and 6B to the coating bar 5 is set so that the pressing force is always substantially constant within the usage range of the coating bar 5. Yes.

  That is, FIG. 2 is a schematic perspective view showing details of the coating bar 5 as a solid lubricity imparting member and related members. In the same figure, 6A and 6B are two types of elastic members having different characteristics from each other, a pressing spring which is a lubricity imparting agent pressing spring, and 10 is a lubricity imparting agent retaining sheet metal (hereinafter referred to as retaining sheet metal). Each is shown.

  As shown in FIG. 2, the coating bar 5 is solidified with zinc stearate as a main component as a lubricity imparting agent, and is formed in a rectangular parallelepiped shape having a predetermined dimension. It has a uniform single layer structure with machinability. That is, the length of the coating bar 5 in the longitudinal direction is set to at least the maximum length of the image forming area where an image in the longitudinal direction of the surface of the photosensitive drum 1 is generated. Uniformly, zinc stearate can be supplied only through the fur brush 4 that is rotationally driven. The thickness of the coating bar 5 in the direction toward the fur brush 4 is a predetermined dimension that takes into account the restrictions on the installation space of the coating bar 5 and the necessity of frequent replacement as a consumable item. Is set.

  On the back side of the coating bar 5, the ability to reinforce the rigidity of the coating bar 5 and maintain its shape is enhanced, and the pressing force supplied from the pressing springs 6A and 6B is evenly distributed over the entire longitudinal direction. A holding sheet metal 10 is integrally attached as a member for transmitting to the sheet. That is, the holding metal plate 10 has a substantially large rectangular shape similar to the shape of the back surface of the coating bar 5, and one long side thereof has a rib connected to the long side and extending to the coating bar 5 side. The parts are integrally formed. Accordingly, the rigidity of the holding sheet metal 10 itself is increased by the rib portion, and the rib portion is in contact with the side surface of the coating bar 5 to prevent the positional deviation beyond the rib portion of the coating bar 5. The holding sheet metal 10 can be stably and reliably held.

  Then, the holding metal plate 10 includes two kinds of pressing springs 6A and 6B as pressing members in parallel, and the pressing spring 6A and the pressing spring 6B are pressed against the central portion of the holding metal plate 10 in the longitudinal direction. A configuration in which the spring 6B is arranged in parallel is installed symmetrically. That is, a combination of the pressing spring 6 </ b> A and the pressing spring 6 </ b> B is provided symmetrically in the longitudinal direction of the holding sheet metal 10 at one end and the other end of the holding sheet metal 10. In other words, a pair of pressing springs 6A are provided symmetrically around the central portion of the holding metal plate 10 in the longitudinal direction, that is, the central portion of the holding metal plate 10 corresponding to the central portion of the image forming area. A pair of pressing springs 6B are provided symmetrically in the vicinity and outside of the pressing spring 6A.

  Therefore, since the pair of pressing springs 6A and the pair of pressing springs 6B are arranged symmetrically at both ends of the holding sheet metal 10 with the central part of the holding sheet metal 10 as the center, the pressing springs 6A The pressing force supplied from the springs 6A and 6B is equally applied to both end portions of the holding metal plate 10 regardless of the amount of expansion and contraction of the pressing springs 6A and 6B. That is, the pressing force FR and the pressing force FL shown in FIG. The coating bar 5 to which the pressing force is transmitted through the holding metal plate 10 having the predetermined rigidity strength is applied to the pressing spring 6A and the pressing spring as uniform surface pressure over the entire area of the rear surface. The pressing force FA from 6B is received. As a result, the lower end surface as the front surface of the coating bar 5 facing the fur brush 4 side is uniformly in contact with the longitudinal direction of the rotating outer peripheral surface of the fur brush 4 over the entire longitudinal direction.

  And these press springs 6A and 6B are the sum total supplied from both press springs 6A and 6B in the normal use range from the start to the end of the use in which each characteristic consumes and supplies the coating bar 5. The variation of the pressing force is set to be small. That is, the pressing spring 6A and the pressing spring 6B are substantially cylindrical coil springs having linear characteristics, and the amount of deflection in the coil axis direction is proportional to the compression load (coil axis load). Is proportional to the spring constant. In this embodiment, various characteristics such as the spring constant and dimensions are set to a predetermined value to reduce fluctuations in the pressing force obtained as a sum from the pressing springs 6A and 6B. ing.

  More specifically, the spring length of the pressing spring 6A is longer than that of the pressing spring 6B, and the spring constant is set lower than that of the pressing spring 6B. In other words, the pressure spring 6A has a spring length that is a natural length in an unloaded state, which is longer than the spring length of the pressure spring 6B in the same unloaded state. The spring constant as the strength of the elastic restoring ability with respect to the unit deformation amount compressed in the length direction is set to be lower than the spring constant of the pressing spring 6B.

  Thus, for example, the combination of the spring constant and the spring length as the characteristics of the pressing spring 6A and the combination of the spring constant and the spring length as the characteristics of the pressing spring 6B are shown in the graph of FIG. As shown in FIG. 5, if the range Ls in the figure is set as the use range, at least the pressing force F (6A + 6B) obtained as the sum of these pressing springs 6A and 6B in this range Ls is The variation can be reduced compared to the pressing force F (conventional) when a single type of spring is used.

  That is, as clearly indicated by a solid line in the figure, in a single type of spring, that is, a spring having one spring constant and one natural length, naturally, depending on various setting values of these characteristics, The pressing force obtained in accordance with the increase in the spring compression length is a monotonically increasing structure, and from the state in which the new coating bar 5 that has not been consumed is pressed, that is, from the maximum pressing force with the maximum compression amount, The pressing force F monotonously decreases with the consumption of the coating bar 5, that is, with the decrease of the compression amount following this.

  On the other hand, a pressing spring 6A in which the spring length is set relatively long as the natural length difference represented by LD in FIG. According to the configuration of this embodiment in which the pressing springs 6B, in which the spring length is set relatively short and the spring constant is set relatively high, are arranged in parallel, the sum from these pressing springs 6A, 6B. As for the pressing force F (6A + 6B) obtained as follows, the change can be made smaller than the pressing force F by the conventional single type spring. That is, although the pressing force F (6A + 6B) shows a linear change similarly to the change of the pressing force F by the conventional single type spring, the change of the pressing force F shown by the solid line in FIG. Compared to the represented graph line, the slope of the graph line indicated by a broken line in FIG. 3A is gentler, and the fluctuation can be reduced.

  In addition, in each figure of FIG. 3, in order to make comparability with the past easy to understand, it represents on the basis of the compression state of the press spring 6B according to the conventional single type spring. That is, since the difference LD of the natural length is set, the pressing spring 6A starts to be compressed before the pressing spring 6B. Therefore, the change line of the pressing spring 6A is mainly based on the compression amount of the pressing spring 6B. The base point is the place on the left side beyond the “0” point on the horizontal axis shown in FIG. Further, the use range Ls of the coating bar 5 shown in each figure is such that the right end is the unconsumed start state of the new coating bar 5 and the left end is immediately before the replacement of the coating bar 5 that has been consumed up to the use limit. When the image forming apparatus actually performs the image forming operation and the coating bar 5 is consumed, the compression amount of the pressure springs 6A and 6B is increased from the right end in the use range Ls according to the consumption amount. Go to the left edge and change.

  Further, in FIG. 3A, the lengths of the straight lines representing the change of the pressing force proportional to the compression amount of the pressing spring 6A and the pressing spring 6B intersect each other. However, the present invention is not limited to this, and as shown in the graph of FIG. 3B, the ends of the graph lines of the two pressing springs 6A and 6B are made to coincide with each other. Various dimensions and spring constants may be set so as to generate the same pressing force at the maximum compression amount, or may be set so as not to cross each other as shown in the graph of FIG. The maximum pressing force allowed by the unconsumed coating bar 5, the minimum pressing force required for the coating bar 5 whose consumption is close to the maximum limit, and the coating bar 5 as the use range described above In response to consumable amount, in consideration of such strokes of said spring to choose from the compression range of the spring, as appropriate, shall be set by selecting the various dimensions and spring constant.

  Therefore, in order to bias the lubricity imparting member to a predetermined value, compared to a configuration using a single type of spring as a pressing member, that is, a configuration using a spring in which a spring constant is set as one elastic characteristic, The fluctuation range of the pressing force supplied as the elastic restoring force of the spring can be greatly reduced. That is, use of the coating bar 5 that has been ground for supply from the state of the coating bar 5 that has not been used after being replaced with a new one, that is, the unused coating bar 5 and whose thickness in the pressing direction has been reduced to a predetermined value. Fluctuation in the pressing force can be reduced and the supply amount of the lubricity-imparting agent can be made substantially constant within the service range Ls of the lubricity-imparting agent that is defined as the state up to the state immediately before replacement after the end of the life. Can do.

  In particular, as the lubricity imparting agent is consumed, the weight of the imparting agent itself is reduced, and the necessary pressing force is reduced. Therefore, the fluctuation of the pressing force can be obviously reduced as compared with the conventional single type spring. According to the configuration of this embodiment, a substantially almost constant pressing force can be secured per unit weight of the lubricity imparting agent whose weight changes in this way, and as a result, as an image carrier. It becomes possible to make the supply amount of the lubricity imparting agent constant to a sufficient level.

  Further, the end portions of the pressing springs 6A and 6B that are in contact with the holding metal plate 10 are coupled by a predetermined method, and the pressing springs 6A and 6B are integrally formed with the holding metal plate 10. Each of the pressing springs 6A and 6B is integrally provided on the holding metal plate 10 while maintaining an upright posture at the above location.

  That is, one end of each of the pressing springs 6A and 6B is welded to a predetermined mounting position on the holding metal plate 10 by a thermal action by heating, a chemical action by a solvent, an ultrasonic vibration action, an adhesive, or the like. And a caulking structure in which an engagement portion having a predetermined hook shape or the like is formed at a mounting location, and either or both of the engagement portion and one end of the spring are plastically deformed to be engaged with each other so as not to be detached. 4A and 4B are provided at the mounting location, and one end of the spring is elastically deformed in the mounting process so that it cannot be detached. As described above, an appropriate coupling method or a configuration using a coupling means is employed, and the pressing springs 6A and 6B are coupled to the holding metal plate 10 so that the both 6A, 6B, and 10 are integrated.

  In particular, in the locking and coupling configuration 11 shown in FIGS. 4A and 4B, the pressing springs 6A and 6B can be stably held in the upright posture with respect to the holding metal plate 10, and the pressing spring 6A is held on the holding metal plate 10. , 6B can be easily attached and detached. That is, one end of the pressing springs 6A and 6B on the side of the sheet metal is formed in an arm shape with one end shown in FIG. 4A extending in the spring radial direction and having a predetermined width in the extending direction. A pedestal portion 12 is provided, and the pedestal portion 12 is locked to the locking portion 13 having the structure shown in FIG. 4B so as not to be detached outside a predetermined manual operation.

  One end of the pedestal portion 12 extends in a predetermined length in the spring radial direction, and the extended tip draws a semicircle of the approximate spring diameter and has a predetermined length in a direction opposite to the extended spring radial direction. And is folded so that its final end is located between the two extended. Therefore, the pedestal portion 12 has a substantially long plate shape with the peripheral edge of the lower surface secured to have a predetermined width, and the length direction of the spring portion continuous to the pedestal portion 12 is directed to a direction orthogonal to the lower surface. ing. For this reason, if the lower surface periphery of the base part 12 is installed in contact with the upper surface of the holding metal plate 10, the pressing springs 6A and 6B are attached to the upper surface in an upright posture.

  The locking portion 13 is engaged with the positioning portion 13a formed on the holding metal plate 10 so as to protrude in a hemispherical shape corresponding to the spring diameter and the arcuate tip of the pedestal portion 12 on the above-mentioned location. A claw portion 13b to be joined, and at least a cover or an intermediate holding portion 13c inserted into the portion between the claw portion 13b and the positioning portion 13a. Each part 13a-13c is integrally formed by deforming the punching process or the cut part of the holding metal plate 10 without using a separate member.

  Therefore, according to this lock coupling structure 11, when the pressing springs 6A and 6B are attached to the holding metal plate 10, the spring circular portion on the base end side of the pedestal portion 12 is first fitted into the positioning portion 13a. The base part 12 is elastically deformed between the front end and the base end of the base part 12 while the front end is hooked on the claw part 13b, and the elastically deformed intermediate part is returned to a straight line and slid to the intermediate holding part 13c. Alternatively, while elastically deforming the middle between the front end and the base end of the pedestal portion 12 to a predetermined degree, the front end is inserted into the intermediate holding portion 13c to reach the claw portion 13b and hooked on the claw portion 13, and the pedestal portion If the spring circular portion on the proximal end side of 12 is fitted to the positioning portion 13a and the elastic deformation is released, the pressing springs 6A and 6B cannot be detached and are in an upright posture. It can be attached to the holding sheet metal 10. That is, it is possible to prevent the pressing springs 6 </ b> A and 6 </ b> B having the above posture from being detached from the holding metal plate 10 unless the above operation is performed artificially.

  As described above, according to this embodiment, when the fur brush rotates, the lubricity imparting agent is scraped, and the pressing force of the spring pressing the lubricity imparting agent as the lubricity imparting member changes with time. By doing so, the supply amount of the lubricity imparting agent can be made constant. Further, it is not necessary to provide a new space, and a compact configuration is possible.

  That is, as compared with the conventional configuration in which one type of spring is provided as the pressing member of the lubricity imparting member, the configuration of this embodiment is merely arranged in parallel with the above two types of springs. And the member that supports the other end of the spring in contact with the lubricity imparting agent, a little extra space is consumed by the number of springs of the second type, and there is an additional space in other cleaning devices. Saves space. Therefore, at least a compact configuration can be maintained as the cleaning device. For this reason, for example, it is not necessary to press various members provided around the cleaning device, and it is not necessary to restrict the arrangement of these members.

  Furthermore, since the pressing member is attached to the sheet metal that reinforces the lubricity-imparting agent without using the fastening member, it is not necessary to fasten with a screw or the like, so that the cost can be reduced. That is, since fastening parts such as screws are not required, the number of parts can be reduced, the assembly cost can be reduced, and the cost can be reduced.

  In addition, by using two types of springs with different spring constants, it is possible to maintain a substantially constant pressing force within a specified range, to keep the supply of the lubricant imparting agent to the photoreceptor constant, and to stabilize the image quality. Can be achieved.

  Furthermore, since the spring is manufactured integrally with the sheet metal, the number of parts can be reduced. For this reason, assembly man-hours can be reduced and costs can be suppressed.

  Moreover, as a lubricity imparting agent, by using a solidified single layer of zinc stearate, quality can be stabilized in production. That is, since the lubricity imparting agent has a single-layer solid structure of zinc stearate, the manufacturing process is simplified, and the quality can be stabilized and the cost can be reduced.

  Furthermore, the cleaning device having the above-described configuration, the photosensitive drum as the image carrier, and at least the charging device are integrated into a single process cartridge configuration, Since it can be attached to and detached from the main body of the device, if the device or member housed in the cartridge is worn out or a failure occurs, the cartridge can be replaced with a new one and quickly returned to the new state. An image forming apparatus with improved properties can be obtained. On the other hand, by simply replacing the process cartridge having the conventional configuration with the process cartridge having the configuration of this embodiment, the image forming apparatus has the above-described various functions and effects without changing the apparatus configuration of the image forming apparatus itself. can get. For this reason, application to a process cartridge exchange type image forming apparatus is easy, and a wide application range can be obtained.

  In the above-described embodiment, the two types of springs have the same compression spring configuration even though the spring constants and the natural lengths are different. However, the two types are not limited thereto. It is good also as a structure of this tension spring, and also it is good also as a structure which combined the compression spring and the tension spring.

1 is a schematic cross-sectional view of a process cartridge as a main part of the image forming apparatus according to an embodiment of the image forming apparatus of the present invention. It is a schematic perspective view showing details of a coating bar and related members as lubricity imparting members used in the image forming apparatus of this embodiment. The comparison between the configuration pressed by the two types of springs in this embodiment and the configuration pressed by a single type of conventional spring is shown, and (a) shows a setting in which the graph lines of the two types of springs intersect each other. The comparison between the configuration of the embodiment and the conventional configuration, (b) shows the comparison between the other configuration of this embodiment and the conventional configuration in which the graph line ends of the two types of springs are matched. These are graphs each showing a comparison between the configuration of this embodiment and the conventional configuration in which the graph lines of the two types of springs are not in contact with each other. The detail of the spring of the structure produced integrally with the sheet metal of this embodiment is shown, (a) is a schematic perspective view of a spring single-piece | unit, (b) is a schematic longitudinal cross-sectional view which shows the state with which the spring was integrated with the sheet metal. It is.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Cleaning apparatus 3 Cleaning blade 4 Fur brush 4a Brush shaft 4b Brush hair 5 Coating bar (lubricant imparting agent)
6 Coating bar pressing spring (pressing member)
6A Spring (One of the two types of pressing member)
6B Spring (the other pressing member of the two types)
8 Charging roller (charging device) 9 Cleaning roller (for charging roller)
10 Lubricating agent holding sheet metal (sheet metal) 11 Locking coupling structure (for spring)
12 Spring base part 13 Locking part 100 Process cartridge 101 Paper transport means (travel belt)
A Image forming apparatus

Claims (6)

In an electrophotographic image forming apparatus having an image carrier and provided with a cleaning device for cleaning the image carrier,
The cleaning device includes at least a member that rotates in contact with the image carrier, a solid lubricity imparting agent that contacts the rotating member, and a pressing member that presses the lubricity imparting agent toward the rotating member. ,
The pressing member is configured such that the pressing force supplied to the lubricity-imparting agent is always substantially constant in the usage range of the lubricity-imparting agent, and the supply amount of the lubricity-imparting agent is constant. An image forming apparatus.   The said lubricity imparting agent is provided with a sheet metal that reinforces the lubricity imparting agent, and the pressing member is attached to the sheet metal without using a fastening member. Image forming apparatus.   The image forming apparatus according to claim 1, wherein at least two types of springs having different spring constants are used as the pressing member.   The image forming apparatus according to claim 3, wherein the spring is integrally formed with the sheet metal.   The image forming apparatus according to claim 1, wherein the lubricity imparting agent is zinc stearate.   An image carrier and at least a cleaning device are integrated into a single case. The cleaning device includes at least a member that rotates in contact with the image carrier, and a solid lubricant that contacts the rotating member. And a pressing member that presses the lubricity-imparting agent on the rotating member side. The pressing member has a pressing force supplied to the lubricity-imparting agent within the range of use of the lubricity-imparting agent. The process cartridge is configured so that the pressing force is always substantially constant, the supply amount of the lubricity imparting agent is constant, and the integrated component is detachable from the apparatus main body.

Images