JP2005250346A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain stable development performance by preventing a developing roller, a doctor blade, etc. from causing wear or toner filming. <P>SOLUTION: A belt-like photoreceptor 2 is provided with an application brush 25 that applies a lubricant 26. The lubricant applied to the photoreceptor 2 is spread onto the developing rollers 12, 13, 14, and 15 of a contact developing device via toner in a developing area. By the spread of the lubricant onto each of the developing rollers 12 to 15, each developing roller and the doctor blade (not shown) are prevented from causing developing roller wear or toner filming. This extends the life of the developing device. In addition, since streaky or nonuniform images, a fog phenomenon, etc. can be prevented, the satisfactory capability to develop images is maintained for a long time. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile, and more particularly to a contact developing type image forming apparatus.

  The developer used in the image forming apparatus that develops the electrostatic latent image formed on the photosensitive member to form a visible image includes two-component developer composed of toner and carrier and one-component development composed of toner alone. There is an agent.

  A developing device using a one-component developer generally includes a toner carrier (hereinafter referred to as a developing roller), a toner supply member such as a supply roller, a doctor blade, and the like, and develops toner supplied to the development roller by the toner supply member. The toner is transported toward the developing position by the rotation of the roller, and the thickness of the toner layer is regulated by a regulating member such as a doctor blade in the middle thereof to make a uniform thin layer, and the toner is uniformly charged.

  In the one-component contact development method, since the supply roller and the doctor blade are in sliding contact with the developing roller, the developing roller is worn and toner filming (fixed) occurs, and it is difficult to maintain a predetermined performance for a long time.

  As a countermeasure, for example, in Japanese Patent Laid-Open No. 2000-9129 (Patent Document 1), the rubber composition of the developing roller contains a toner releasable material to prevent the developing roller from being scraped or from toner filming. Has been proposed. Japanese Patent Application Laid-Open No. 11-15260 (Patent Document 2) proposes to prevent toner filming by forming a coating layer having high rubber hardness on an elastic layer.

JP 2000-9129 A Japanese Patent Laid-Open No. 11-15260 JP-A-2-242262 JP-A-11-65137 JP 2002-6632 A

  However, even the techniques of Patent Documents 1 and 2 are not sufficient for preventing the developing roller from being scraped or to prevent toner filming. In the long-term use, the surface of the developing roller is scraped or filmed. There have been problems such as streaks and density unevenness on the image, and fogging due to unstable toner charging.

  In contact development, since the photosensitive member and the developing roller are always in contact with each other and rotate with a difference in peripheral speed, the surface of the photosensitive member is more easily scraped than in non-contact development. On the other hand, in JP-A-2-242262 (Patent Document 3) and JP-A-11-65137 (Patent Document 4), the surface of the photoconductor surface is made to contain friction by containing a silicone component. A method for improving by reducing the coefficient has been proposed. However, although an effect on the surface of the photoreceptor is initially seen, there is a problem that the effect does not continue with time.

  Further, Japanese Patent Laid-Open No. 2002-6632 (Patent Document 5) proposes a method for improving a toner base material by adding a lubricant to a one-component toner obtained by externally adding an external additive. However, since the initial toner and the lubricant added by stirring are separated from the toner and aggregate in the developing device, there is a problem that the toner thin layer cannot be formed uniformly.

  The present invention solves the above-mentioned problems in the case of using a conventional one-component developer, prevents wear and toner filming in the developing roller and doctor blade, etc., and can maintain stable development performance. It is an object to provide an apparatus.

  According to the present invention, there is provided an image forming apparatus that visualizes an electrostatic latent image formed on an image carrier by contact development according to the present invention. A developer carrying member that is conveyed to the image carrier and a layer thickness regulating member that regulates the layer thickness of the developer on the developer carrying member, and a lubricant application device that applies a lubricant to the image carrier is provided, The problem is solved by applying a lubricant to the image carrier by a lubricant application device, and applying the lubricant to the developer carrier and the layer thickness regulating member via the developer.

In order to solve the above-described problems, the present invention proposes to provide a controllable amount of lubricant applied to the image carrier by the lubricant application device.
In order to solve the above-described problems, the present invention provides the lubricant application device including a brush roller for applying a lubricant to the image carrier, and controlling the number of rotations of the brush roller. We propose that the amount of lubricant applied to the carrier can be controlled.

In order to solve the above problems, the present invention proposes that the amount of lubricant applied to the image carrier can be controlled by changing the linear velocity of the image carrier.
In order to solve the above problems, the present invention proposes to discharge the developer stored in the developing device every predetermined number of image formations.

In order to solve the above problems, the present invention proposes to discharge the developer when the lubricant contained in the developer exceeds 0.5 wt%.
In order to solve the above-described problem, the present invention provides that the lubricant is applied to the image carrier by the lubricant application device during the non-development operation of the developing device and the operation of the image carrier. suggest.

In order to solve the above problems, the present invention proposes that the charging polarity of the lubricant is opposite to the charging polarity of the developer.
In order to solve the above problems, the present invention proposes that the initial developer and the replenishment developer used in the image forming apparatus do not contain a lubricant.

  In order to solve the above problems, the present invention proposes that at least the image carrier and the developing device are integrated into a unit and configured as a process cartridge that can be attached to and detached from the image forming apparatus main body.

  According to the image forming apparatus of the present invention, the lubricant is applied to the developer carrier and the layer thickness regulating member via the developer by applying the lubricant to the image carrier by the lubricant application device. Scraping of the member and toner filming in the agent carrier and the layer thickness regulating member are prevented, and the life of the developing device can be extended. In addition, it is possible to prevent streaks, unevenness, or fogging phenomenon in an image and to maintain a good developing ability over time.

  According to the second aspect of the present invention, the lubricant application amount to the image carrier by the lubricant application device is provided so as to be controllable, so that excessive supply of the lubricant can be prevented and the formation of the toner thin layer is inhibited. There is no.

According to the third aspect of the present invention, the amount of lubricant applied to the image carrier can be controlled by controlling the number of rotations of the brush roller, so that the amount of lubricant applied can be easily controlled.
According to the fourth aspect of the present invention, since the amount of lubricant applied to the image carrier can be controlled by changing the linear velocity of the image carrier, excessive supply of the lubricant can be prevented, and the toner thin layer can be formed. There is no hindrance.

  According to the configuration of the fifth aspect, the developer stored in the developing device is discharged every time the image is formed a predetermined number of times, so that the amount of lubricant contained in the toner does not become too high, and the developer carrier and the layer It is possible to prevent excessive supply of the lubricant to the thickness regulating member.

  According to the configuration of the sixth aspect, since the developer is discharged when the lubricant contained in the developer exceeds 0.5 wt%, excessive supply of the lubricant can be prevented and the formation of the toner thin layer is inhibited. There is nothing to do.

  According to the configuration of claim 7, since the lubricant is applied to the image carrier during the non-development operation of the developing device and the image carrier, the linear velocity of the image carrier during the development operation is not affected. Further, the influence of residual toner can be prevented.

With the configuration according to the eighth aspect, the lubricant can be efficiently applied to the developer carrier and the layer thickness regulating member because the charge polarity of the lubricant is opposite to the charge polarity of the developer.
According to the structure of the ninth aspect, since the initial developer and the replenishment developer do not contain the lubricant, the aggregation of the lubricant that occurs when the lubricant is added to the developer and the decrease in the fluidity of the developer are caused. Does not occur.

  With the configuration of the tenth aspect, the process cartridge can be downsized to contribute to downsizing of the image forming apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram schematically showing the vicinity of an image forming unit in an example of an image forming apparatus according to the present invention. FIG. 2 is a side view showing the photoreceptor and the proximity charging device. FIG. 3 is an enlarged view showing the vicinity of the proximity charging device and the lubricant application device in detail.

  The image forming apparatus of this embodiment shown in these drawings is configured as a digital color printer, and is a so-called intermediate transfer type image forming apparatus. The belt-like photosensitive member 2 is stretched over a driving roller 5, a driven roller 6, a primary transfer counter roller 7, a tension roller 8 and a backup roller 9, and is passed through the driving roller 5 by a photosensitive member driving motor as a driving source (not shown). It is rotationally driven in the direction of arrow A (clockwise in the figure).

  As shown in FIG. 2, the charging roller 1 constituting the proximity charging device is disposed in proximity to the photosensitive member 2 on the driving roller 5 and is a spacer ring 3 as an annular abutting member that abuts against the photosensitive member 2. 4 is fitted to both ends opposite to the non-charged surface of the photosensitive member 2 and the core bars 1a at both ends are pressed toward the photosensitive member 2 by the pressure springs 10 and 11, whereby the photosensitive member 2 is charged. A minute distance between the surfaces is kept constant. The charging roller 1 uniformly charges the surface to be charged of the photoconductor 2 by discharging to the photoconductor 2 at a minute interval between the surface of the photoconductor 2 and the surface to be charged. For the spacer rings 3 and 4, for example, an insulating tape having a thickness of 80 μm and a width of 8 mm is used.

  On the left side of the photosensitive member 2 in the figure, a magenta developing device having a developing roller 12, a cyan developing device having a developing roller 13, a yellow developing device having a developing roller 14, a black developing device having a developing roller 15, and the surface of the photosensitive member 2. A density sensor 16 for detecting the density of the light is sequentially arranged from the bottom to the top of the figure. In this figure, each color developing device shows only developing rollers 12, 13, 14, and 15 as toner carriers. In this embodiment, each color developing device is configured to be movable so that the developing roller can be brought into contact with and separated from the photosensitive member 2. Basically, the developing roller is brought into contact with the photosensitive member 2 only during the developing operation. Each color developing device in this embodiment has the same configuration as a conventionally known one-component contact developing device. In each color developing device, a doctor blade (not shown) as a toner layer thickness regulating member in addition to the developing roller. It has.

  An intermediate transfer belt 17 as an intermediate transfer member is stretched on the right side of the photoconductor 2. The intermediate transfer belt 17 is stretched over a driving roller 18, driven rollers 19 and 20, a tension roller 21, and a primary transfer roller 22, and is passed between the primary transfer roller 22 and the primary transfer counter roller 7 to be photosensitive. It is in contact with the body 2. Further, the secondary transfer roller 23 constituting the secondary transfer device is disposed on the driving roller 18 so as to contact the intermediate transfer belt 17.

  On the right side of the portion between the primary transfer position and the charging position of the photoreceptor 2, a static elimination lamp 24 constituting a static elimination device, a lubricant application brush 25 as a brush material constituting a lubricant application device, and a lubricant 26. A cleaning device 28 having a cleaning blade 27 as a cleaning member is disposed. Further, a cleaner 29 for cleaning the charging roller 1 and a waste toner bottle 30 are provided.

  The lubricant application brush 25 is provided with a large number of bristles on the outer peripheral surface of the central axis extending in the width direction of the photosensitive member 2, that is, the axial direction of the lubricant application brush 25. For example, the brush is implanted on a base cloth (not shown). And it is comprised by fixing the base fabric to the outer peripheral surface of a center axis | shaft. The tip of the lubricant application brush 25 is in contact with the surface of the photoreceptor 2 over almost the entire width, and is always in contact with the lubricant 26.

  Further, the rotation axis (center axis) of the lubricant application brush 25 extends from the surface of the photoreceptor 2 in a direction perpendicular to the paper surface of FIG. Is rotatably supported on the front and rear side walls of the case, and is driven to rotate in an appropriate direction, for example, in the direction of arrow C (clockwise in the figure) by a driving device (not shown). At the contact portion between the lubricant application brush 25 and the surface of the photoreceptor 2, the rotation direction of the lubricant application brush 25 is set so that the lubricant application brush 25 and the surface of the photoreceptor 2 move in opposite directions. Yes.

  The lubricant application brush 25 rotating in the direction of arrow C scrapes the lubricant from the solid lubricant 26 little by little by contacting the solid lubricant 26. The lubricant thus transferred to the lubricant application brush 25 is applied to the surface of the photoreceptor 2 driven in the direction of arrow A while being in contact with the lubricant application brush 25.

  As the solid lubricant 26, for example, a dry solid hydrophobic lubricant is used, and typical examples thereof include zinc stearate, barium stearate, zinc stearate, iron stearate, nickel stearate, cobalt stearate, stearic acid. Copper, strontium stearate, calcium stearate, cadmium stearate, magnesium stearate, zinc oleate, manganese oleate, iron oleate, cobalt oleate, lead oleate, magnesium oleate, copper oleate, palmitic acid, zinc partimine Cobalt oxide, copper palmitate, magnesium palmitate, aluminum palmitate, calcium palmitate, lead caprylate, lead caproate, zinc linolenate, cobalt linolenate, calcium linolenate, and lithium Such relatively higher fatty acid such as linoleic acid cadmium and the like. As the solid lubricant 26, a natural wax such as carnauba wax can be used.

  The basic specifications of the digital color laser printer of this embodiment are: linear velocity: 178 mm / sec, image portion surface potential of the photoreceptor 2 as an image carrier: −500 V, charging roller as a charging member 1: core having a diameter of 9 mm, for example A charging roller having a diameter of 12 mm, in which a hydrin rubber layer is provided on gold.

Next, a full color image forming operation in the digital color laser printer of this example will be described.
The photosensitive member 2 is rotationally driven by a photosensitive member driving motor to rotate in the direction of arrow A, and the intermediate transfer belt 17 is rotationally driven in the direction of arrow B through a driving roller 18 by a driving source (not shown). A charging bias is applied to the charging roller 1 from a power source (not shown), and a transfer bias is applied to the primary transfer roller 22 and the secondary transfer roller 23 from a power source (not shown). The photoreceptor 2 is uniformly charged by the charging roller 1 and is exposed to an image by an exposure unit (not shown), for example, a laser writing device, in accordance with a magenta image signal from the outside to form an electrostatic latent image. The electrostatic latent image on the photosensitive member 2 is developed by a magenta developing device having a developing roller 12 to become a magenta toner image. This magenta toner image is transferred onto the intermediate transfer belt 17 by the primary transfer roller 22 at the primary transfer position. Transcribed. After passing through the primary transfer position, the photoreceptor 2 is neutralized by the neutralizing lamp 24, applied with the lubricant by the lubricant application brush 25, and cleaned by the cleaning blade 27.

  Next, the photoreceptor 2 is uniformly charged again by the charging roller 1, and image exposure is performed in accordance with a cyan image signal from the outside by a laser writing device (not shown) to form an electrostatic latent image. The electrostatic latent image on the photoreceptor 2 is developed by a cyan developing device having a developing roller 13 to become a cyan toner image, and this cyan toner image is transferred onto the intermediate transfer belt 17 by the primary transfer roller 22 at the primary transfer position. The magenta toner image is superimposed and transferred. After passing through the primary transfer position, the photoreceptor 2 is neutralized by the neutralizing lamp 24, applied with the lubricant by the lubricant application brush 25, and cleaned by the cleaning blade 27.

  Next, the photosensitive member 2 is again uniformly charged by the charging roller 1, and image exposure is performed in accordance with a yellow image signal from the outside by a laser writing device (not shown) to form an electrostatic latent image. The electrostatic latent image on the photoreceptor 2 is developed by a yellow developing device having a developing roller 14 to become a yellow toner image. This yellow toner image is transferred onto the intermediate transfer belt 17 by the primary transfer roller 22 at the primary transfer position. The magenta toner image and the cyan toner image are superimposed and transferred. After passing through the primary transfer position, the photoreceptor 2 is neutralized by the neutralizing lamp 24, applied with the lubricant by the lubricant application brush 25, and cleaned by the cleaning blade 27.

  Next, the photosensitive member 2 is again uniformly charged by the charging roller 1, and image exposure is performed in accordance with a black image signal from the outside by a laser writing device (not shown) to form an electrostatic latent image. The electrostatic latent image on the photosensitive member 2 is developed by a black developing device having a developing roller 15 to become a black toner image. This black toner image is transferred onto the intermediate transfer belt 17 by the primary transfer roller 22 at the primary transfer position. A full-color image is formed by being superimposed and transferred with a magenta toner image, a cyan toner image, and a yellow toner image. After passing through the primary transfer position, the photoreceptor 2 is neutralized by the neutralizing lamp 24, applied with the lubricant by the lubricant application brush 25, and cleaned by the cleaning blade 27.

  Then, a transfer sheet as a transfer material is fed from a sheet feeding device (not shown), and a full-color image on the intermediate transfer belt 17 is transferred to the transfer sheet by the secondary transfer roller 23 and is discharged to the outside as an image formed product. . Further, the charging roller 1 is cleaned by the cleaner 29, and the intermediate transfer belt 17 is cleaned by a cleaning device (not shown).

  By the way, the lubricant applied to the photosensitive member 2 is cleaned by the cleaning blade 27, and at that time, the lubricant is leveled by the blade and uniformly adhered to the photosensitive member 2. The lubricant adhering to the photoreceptor adheres to each developing roller via the toner in the developing area. That is, during the developing operation, the toner in contact with the photosensitive member background portion contacts the photosensitive member coated with the lubricant, takes in the lubricant, and supplies the lubricant to the developing roller. The toner and the photoconductor are in contact with each other on the surface of the photoconductor, but the toner on the developing roller does not move to the photoconductor but returns to the developing device. Is returned to the developing device.

  As the lubricant adheres to the developing rollers 12 to 15 in this way, the developing rollers 12 to 15 and a doctor blade (not shown) in each color developing device are prevented from being scraped or to toner filming. . Thereby, the lifetime of the developing device can be extended. In addition, it is possible to prevent streaks, unevenness, or fogging phenomenon in an image and to maintain a good developing ability over time.

  If the charging polarity of the lubricant applied to the photosensitive member 2 is opposite to the charging polarity of the toner, it can be efficiently moved from the photosensitive member 2 to each developing roller (12 to 15) by the developing electric field. Therefore, it is possible to more efficiently supply the lubricant to the developing roller and the doctor blade.

  In this embodiment, as shown in FIG. 1, the lubricant application device (lubricant application brush 25 and lubricant 26) is located downstream of the primary transfer position (downstream in the moving direction of the photoreceptor 2). The photosensitive member 2 is disposed so as to come into contact with the photosensitive member 2 upstream of the cleaning position of the photosensitive member 2 (position of the cleaning blade 27). By disposing the lubricant application device at such a position, the amount of lubricant applied to the photoreceptor 2 is regulated by the cleaning blade 27, so that excessive application of lubricant is suppressed.

  Further, by configuring the lubricant application brush 25 to be able to be switched between rotation and stop, the lubricant applied to the photoreceptor 2, that is, the lubricant supplied to the developing roller and the doctor blade via the toner is limited. Therefore, it is possible to prevent the friction coefficient of the developing roller from being excessively lowered and the formation of the toner thin layer is not hindered.

  Here, when the developing device is in a non-development operation and the photoconductor 2 is operating, for example, if the lubricant application brush 25 is rotated between papers to control the photoconductor 2 to apply the lubricant, The linear velocity of the photosensitive member 2 during operation is not affected, and there is no contamination of the lubricant or application brush by residual toner on the photosensitive member.

  Further, the lubricant applied to the photosensitive member 2, that is, the lubricant supplied to the developing roller and the doctor blade via the toner can be adjusted by configuring the rotational speed of the lubricant application brush 25 to be controllable. Therefore, it is possible to prevent the friction coefficient of the developing roller from being excessively lowered and the formation of the toner thin layer is not hindered.

  A configuration in which the amount of lubricant is limited and controlled using the photoconductor 2 instead of limiting and controlling the amount of lubricant by the lubricant application device is also possible. For example, the lubricant supplied to the developing roller and the doctor blade via the toner may be limited and controlled by changing the linear velocity of the photosensitive member 2 except during the developing operation and the transfer process, preferably between papers. it can. In this case, the lubricant supplied to the developing roller and the doctor blade can be reduced by reducing the linear velocity of the photosensitive member 2.

  As the toner used in the apparatus of this embodiment, an external additive for stabilizing charging property and ensuring fluidity is added. However, as described in Patent Document 5, the external additive for imparting lubricity is added. No agent (lubricant) is added. When a lubricant is added, the lubricant (having a property of easily aggregating) may be separated from the toner by stirring, and may aggregate in the developing device or deteriorate the fluidity of the toner. However, in this embodiment, by using the toner to which the lubricant is not added as the initial toner and the replenishing toner, such a problem does not occur, and a thin toner layer can be uniformly formed on the developing roller. Performance can be demonstrated.

  By the way, when the print output with a small image area continues, there is a possibility that the lubricant adheres excessively on the developing roller. Therefore, it is preferable to forcibly discharge the toner in the developing device when a predetermined number of images are formed. For example, the toner in the developing device is forcibly discharged by attaching the toner to the photosensitive member 2 by a developing operation about once every 1000 jobs and transferring the toner onto a sheet or cleaning with the cleaning blade 27. However, the execution frequency of the discharge mode may be set as appropriate. For example, the upper limit of the lubricant contained in the toner is 0.5% wt or less (the upper limit of the lubricant does not exceed 0.5% wt). Frequency is desirable. The number of output sheets in which the upper limit of the lubricant contained in the toner exceeds 0.5% wt may be obtained in advance in the image forming apparatus.

  FIG. 4 is a graph showing the relationship between the number of output sheets and toner filming of the developing roller in comparison between the present embodiment and the conventional example. The horizontal axis is the number of output sheets. The vertical axis represents the toner filming rank in the developing roller, and a higher value represents a better state. In this graph, Examples A, B, and C are those of the present embodiment, where B is a toner to which the lubricant is not added, C is a case where the forced discharge control of the toner is performed, and A is a This is the case when B and C are excluded.

  As can be seen from the graph of FIG. 4, in the conventional example, the rank of toner filming on the developing roller is reduced from the point when the number of output sheets exceeds 12,000. In this embodiment, any one of A, B, and C is used. Also in this case, it can be seen that toner filming is effectively prevented even after 20000 sheets or more.

FIG. 5 shows another example of the image forming apparatus, and is a configuration diagram showing a process cartridge of the image forming apparatus having a drum-shaped photosensitive member.
The process cartridge 50 shown in this figure includes a charging unit 52, a developing unit 53, a cleaning unit 54, a lubricity imparting agent applying unit 55 and the like arranged around the photosensitive drum 51 as a cartridge, and an image forming apparatus (not shown). The main body is detachably provided. The developing device 53 is a one-component contact developing device, and includes a developing roller 56 as a toner carrier, a doctor blade 57 as a toner layer thickness regulating member, a supply roller 58 as a toner supply member, and the like. The lubricity-imparting agent applying means 55 has an arbitrary configuration capable of applying the lubricity-imparting agent to the photosensitive drum 51. For example, the lubricity-imparting agent applying unit 55 can be configured similarly to the lubricant 26 and the lubricant applying brush 25 in FIG. it can.

  The lubricity imparting agent applied to the photosensitive drum 51 from the lubricity imparting agent applying unit 55 adheres to the developing roller 56 of the developing device via the toner in the developing region. The lubricity imparting agent adhering to the developing roller 56 prevents the developing roller from being scraped and toner filming at the portion where the developing roller 56 and the doctor blade 57 are pressed.

  You may comprise so that the charge polarity of a lubricity imparting agent may become a polarity opposite to the charge polarity of a toner. In addition, the amount of lubricity imparting agent applied to the photosensitive drum 52 can be limited or controlled. Alternatively, the amount of lubricity imparting agent applied may be controlled by controlling the number of revolutions of the photosensitive drum 52. Further, it is preferable to use a toner to which no lubricant is added. Further, the toner in the developing device 53 may be forcibly discharged when a predetermined number of images are formed.

  In this embodiment, since the lubricity imparting agent can be applied from the photosensitive member to the developing roller 56 via the toner, the developing roller can be reduced in diameter, and the developing device can be reduced in size. Therefore, the size of the image forming apparatus can be reduced by downsizing the process cartridge 50.

  As mentioned above, although this invention was demonstrated by the example of illustration, this invention is not limited to this. For example, the member that regulates the toner layer thickness on the toner carrier (developing roller) is not limited to a blade (doctor blade), but may be a roller member (layer thickness regulating roller). In addition, the configuration of the developing device may be any configuration, for example, including a toner stirring member.

  The present invention is also applicable when using a two-component developing device. Further, the image forming apparatus is not limited to a printer, and may be a facsimile, a copying machine, or a complex machine thereof. The configuration of the image forming apparatus such as a monochrome apparatus or a tandem color image forming apparatus can be changed as appropriate within the scope of the present invention.

FIG. 2 is a configuration diagram illustrating an outline near an image forming unit in an example of an image forming apparatus according to the present invention. It is a side view showing the photoreceptor and the proximity charging device. It is an enlarged view showing in detail the proximity charging device and the vicinity of the lubricant application device. 6 is a graph showing a relationship between the number of output sheets and toner filming of a developing roller in comparison between an embodiment of the present invention and a conventional example. It is a block diagram of a process cartridge in another example of the image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Charging roller 2 Belt-like photoreceptor 12-15 Developing roller 17 Intermediate transfer belt 22 Primary transfer roller 25 Lubricant application brush 26 Lubricant 28 Cleaning device 30 Waste toner bottle 50 Process cartridge 51 Photosensitive drum 53 Developing device 55 Lubricity Giving agent coating means 56 Developing roller 57 Doctor blade

Claims (10)

In an image forming apparatus that visualizes an electrostatic latent image formed on an image carrier by contact development,
The developing device that performs the contact development includes a developer carrying body that carries the developer and transports it to the development area, and a layer thickness regulating member that regulates the layer thickness of the developer on the developer carrying body,
Provided with a lubricant application device for applying a lubricant to the image carrier, and applying the lubricant to the image carrier with the lubricant application device, the developer carrier and the layer thickness regulation via the developer An image forming apparatus, wherein a lubricant is applied to a member. The image forming apparatus according to claim 1, wherein a lubricant application amount to the image carrier by the lubricant application device is provided so as to be controllable. The lubricant application device has a brush roller for applying a lubricant to the image carrier, and the amount of lubricant applied to the image carrier can be controlled by controlling the number of rotations of the brush roller. The image forming apparatus according to claim 2, wherein the image forming apparatus is characterized. The image forming apparatus according to claim 2, wherein the amount of lubricant applied to the image carrier can be controlled by changing a linear velocity of the image carrier. The image forming apparatus according to claim 1, wherein the developer stored in the developing device is discharged after every predetermined number of times of image formation. The image forming apparatus according to claim 5, wherein the developer is discharged when the lubricant contained in the developer exceeds 0.5 wt%. 2. The image forming apparatus according to claim 1, wherein a lubricant is applied to the image carrier by the lubricant application device during a non-development operation of the developing device and an operation of the image carrier. The image forming apparatus according to claim 1, wherein a charging polarity of the lubricant is opposite to a charging polarity of the developer. 2. The image forming apparatus according to claim 1, wherein the initial developer and the replenishment developer used in the image forming apparatus do not contain a lubricant. The image forming apparatus according to claim 1, wherein at least the image carrier and the developing device are integrated into a unit and configured as a process cartridge that can be attached to and detached from the image forming apparatus main body.

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