JP2014163988A - Lubricant applicator, process unit, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubricant applicator which reliably detects that lubricant has reached the end of service life.SOLUTION: A case 32 houses an application roller 30 which comes into contact with a surface of a photoreceptor drum 2 to apply solid lubricant 33, and a lubricant holding member 31 which moves in a direction of approaching/separating from the application roller 30 while holding the solid lubricant 33. An extension part 31a formed at a longitudinal end of the lubricant holding member 31 protrudes outward from a vertical long hole 32a as an opening formed on an end side wall of the case 32. A movable contact 35b of electric resistance detection means 35 arranged outside the case 32 is pushed by the extension part 31a to be brought into contact with a fixed contact 35a, thereby detecting the service life of the exhausted solid lubricant 33.

Description

  The present invention relates to a lubricant application device, a process unit including the lubricant application device, and an image forming apparatus.

  In image forming apparatuses such as copiers, printers, facsimiles, and composite machines thereof, a solid lubricant such as zinc stearate is applied to a photoreceptor or an intermediate transfer belt by a lubricant application roller to protect them and reduce friction. It has been attempted to increase the coefficient, improve the cleaning property and transfer property, and extend the life. For example, Patent Document 1 (Japanese Patent Laid-Open No. 8-314346) and Patent Document 2 (Patent Document 2) that use a brush roller or the like in contact with the photosensitive member and the lubricant as a coating device for applying a lubricant to the surface of the photosensitive member. No. 3,406,099) is known.

  As shown in FIG. 10, the lubricant application device of Patent Document 1 (Japanese Patent Laid-Open No. 8-314346) includes a lubricant holding member 131 made of a conductive material, and a double-sided tape or the like on the front side of the lubricant holding member 131. Thus, the lubricant 133 is fixed, and a plurality of pressure springs 137 are in contact with the rear side equally. Then, the lubricant 133 is brought into contact with the application roller disposed on the near side by the urging force of the pressure spring 137.

  Both ends of the lubricant holding member 131 constitute an extension part 131a extending longer than the lubricant 133, and the extension part 131a constitutes a contact point for a pair of left and right fixedly arranged regulating members 135 that also serve as electrodes. Yes. When the remaining amount of the lubricant 133 is reduced, the left and right extension portions 131a come into contact with the left and right restricting members 135, the left and right restricting members 135 are brought into conduction, and the detection circuit 138 detects that the lubricant 133 has reached the replacement time. The display circuit 139 displays the image on the operation panel of the image forming apparatus.

  As shown in FIGS. 11A and 11B, the lubricant application device of Patent Document 2 (Japanese Patent No. 340699) is provided with a lubricant application device having an application roller 230 on the downstream side of the application blade 50. The rear end portion of the lubricant 233 of this lubricant application device is supported by a rotatable holding member 234, and the lower surface of the lubricant 233 is in contact with the application roller 230 under its own weight.

  A switch button 235a of a push switch 235 as a detection unit is in contact with an operation unit 234a extending upward from the holding member 234. When the lubricant 233 is consumed and the lifetime is reached, the holding member 234 rotates clockwise by its own weight as shown in FIG. 11B, and the operation portion 234a of the holding member 234 moves away from the switch button 235a. As a result, the push switch 235 is activated, and a signal from the push switch 235 is sent to the display unit 236 via the CPU of the image forming apparatus main body. In the display means 236, a character prompting the user to “replace” is displayed in the display window 236a when the lubricant 233 is exhausted and reaches the end of its life. At the same time, driving of the photosensitive drum 2 and the like related to the image forming operation is stopped.

  In the apparatus of Patent Document 1 (Japanese Patent Laid-Open No. 8-314346), the detection means by the extension portions at both ends of the lubricant holding member and the regulating member are arranged in a case containing the application roller and the lubricant. Also, in the device of Patent Document 2 (Japanese Patent No. 3406999), the push switch 235 is disposed in the case. For this reason, when the powder of lubricant adheres to the contact between the extension part of the cited document 1 and the regulating member and the contact of the switch button of the push switch of Patent Document 2, the continuity is poor despite the contact being closed. Therefore, there is a possibility that the end of the life of the lubricant (including the so-called “near life” just before reaching the end of life) cannot be detected.

  Accordingly, an object of the present invention is to provide a lubricant application device having a detection means that can reliably detect the end of the life of a lubricant.

  In order to solve the above-mentioned problem, the invention of claim 1 holds an application roller for applying a solid lubricant by rotating contact with a surface of an object to be applied, and a solid lubricant arranged in contact with the application roller. A lubricant holding member disposed so as to be movable toward and away from the application roller in a state, a case containing the application roller and the lubricant holding member, and a longitudinal end of the lubricant holding member It is possible to detect the extension portion extending from the opening formed in the case to the outside of the case and the movement of the extension portion disposed on the outside of the case to the predetermined position when the solid lubricant is consumed. And a lubricant applicator.

  In the present invention, the extension portion of the lubricant holding member is extended outside the case, and the movement of the extension portion to a predetermined position is detected by the detection means. Therefore, the solid lubricant powder adheres to the detection means. It is possible to prevent the detection from becoming impossible.

1 is a schematic view of an image forming apparatus using a lubricant application device according to an embodiment of the present invention. It is a schematic sectional drawing of the process unit using the lubricant coating device which concerns on embodiment of this invention. It is a side view at the time of new lubricant of the lubricant application device concerning a 1st embodiment of the present invention. It is a perspective view of the edge part of the lubricant holding member of the lubricant application device concerning a 1st embodiment of the present invention. It is a top view of the edge part of a lubricant holding member of a lubricant application device concerning a 1st embodiment of the present invention, and a detection means. It is a top view which shows the modification which accommodated the detection means of FIG. 3C in the case. It is a side view at the time of the new article of lubricant which shows operation of the lubricant application device concerning a 1st embodiment of the present invention. It is a side view at the time of lubricant life replacement | exchange which shows the action | operation of the lubricant application device which concerns on 1st Embodiment of this invention. It is an edge part perspective view of the lubricant application device concerning a 2nd embodiment of the present invention. It is an edge part top view of the lubricant application device concerning a 2nd embodiment of the present invention. It is an edge part side view of the lubricant application device concerning a 2nd embodiment of the present invention. It is a side view for demonstrating the detection timing of the lubricant coating device which concerns on this invention. It is a side view for demonstrating the detection timing of the lubricant coating device which concerns on this invention. It is explanatory drawing explaining the detection timing of the lubricant coating device which concerns on this invention in relation to the travel distance of an application | coating roller. It is a flowchart which determines the "near lifetime" of the lubricant of the lubricant application device concerning the present invention. It is a side view for demonstrating a detection timing. It is a flowchart which determines the "life" of the lubricant of the lubricant application device concerning the present invention. It is a figure which shows the circuit example of the detection means of the lubricant coating device which concerns on this invention. It is a figure which shows another example of a circuit of the detection means of the lubricant coating device which concerns on this invention. It is a side view at the time of new lubricant which shows the modification (push switch) of the detection means of the lubricant application device concerning the present invention. It is a side view at the time of lubricant life which shows the modification (push switch) of the detection means of the lubricant coating device which concerns on this invention. It is a side view at the time of a new lubricant which shows the modification (photo interrupter) of the detection means of the lubricant application device concerning the present invention. It is a side view at the time of lubricant life which shows the modification (photo interrupter) of the detection means of the lubricant application device concerning the present invention. It is a top view which shows the modification (photo interrupter) of the detection means of the lubricant coating device which concerns on this invention. It is a perspective view which shows the lubricant holding member used for the conventional lubricant application apparatus. It is a side view at the time of new lubricant of another conventional lubricant application device. It is a side view at the time of lubricant life of another conventional lubricant application device.

  Hereinafter, an embodiment of a paper feeding device of the present invention will be described with reference to the accompanying drawings. In each drawing for explaining this embodiment, constituent elements such as members and components having the same function or shape are given the same reference numerals as much as possible to distinguish them, and then the explanation will be given. Is omitted. Further, even for reference numbers with Y, M, C, and Bk in the drawings, for convenience, the Y, M, C, and Bk may be omitted in the following description and described with numbers only. is there.

(Configuration of image forming apparatus)

  FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus shown in FIG. 1 includes four process units 1Y, 1M, 1C, and 1Bk as image forming units. The process units 1Y, 1M, 1C, and 1Bk have the same configuration except that they contain toners of different colors of yellow, magenta, cyan, and black corresponding to the color separation components of the color image.

  Specifically, each of the process units 1Y, 1M, 1C, and 1Bk includes a photosensitive drum 2 as an image carrier (a lubricant application target) and a charging device 3 that charges the surface of the photosensitive drum 2. Have. Further, the image forming apparatus includes a developing device 4 that forms a toner image on the photosensitive drum 2 and a cleaning device 5 that cleans the surface of the photosensitive drum 2. Further, a lubricant application device 6 for applying a lubricant to the surface of the photosensitive drum 2 is provided. The process units 1Y, 1M, 1C, and 1Bk are configured to be detachable integrally with the image forming apparatus main body 10.

  The toner used in this apparatus is a polymerized toner having a spherical shape and a uniform particle size. According to the present invention, since a good lubricant coating layer can be formed on the surface of the photoreceptor, the cleaning performance can be improved by stabilizing the behavior of the cleaning blade, thereby greatly reducing the ratio of residual toner that passes through the cleaning blade. be able to. In addition, high-quality image formation can be achieved by improving the development characteristics and transferability of the polymer toner having a spherical shape and a uniform small particle size.

  Although not shown, a toner bottle filled with toner of each color is provided on the upper portion of the image forming apparatus main body 10. Each color toner in the toner bottle is transferred to a corresponding developing device 4 via a toner transfer pipe (not shown).

  Above each process unit 1Y, 1M, 1C, 1Bk, an exposure device 8 for exposing the surface of each photosensitive drum 2 is disposed. From the exposure device 8, laser light or LED light is irradiated to each photosensitive drum 2.

  A transfer device 9 is disposed below each process unit 1Y, 1M, 1C, 1Bk. The transfer device 9 has an intermediate transfer belt 11 constituted by an endless belt as a transfer body. The intermediate transfer belt 11 is stretched around a plurality of support rollers 12, 13, 14, and 15. One of the plurality of support rollers 12 to 15 (in this embodiment, the support roller 13 at the right end) is a drive roller, and the intermediate transfer belt 11 travels in the direction of the arrow as the roller rotates. It is supposed to be.

  Four primary transfer rollers 16 as primary transfer means are disposed at positions facing the four photosensitive drums 2. A primary transfer nip is formed at a position where the intermediate transfer belt 11 is sandwiched between each primary transfer roller 16 and each photosensitive drum 2.

  Further, a secondary transfer roller 17 as a secondary transfer unit is in contact with the lower outer peripheral surface of the intermediate transfer belt 11 in the drawing. A secondary transfer nip is formed at a position where the intermediate transfer belt 11 is sandwiched between the secondary transfer roller 17 and the support roller 12 facing the secondary transfer roller 17. Further, a belt cleaning device 18 that cleans the surface of the intermediate transfer belt 11 is disposed opposite to the outer peripheral surface of the intermediate transfer belt 11 on the left side of the secondary transfer roller 17.

  Although not shown, a lower part of the image forming apparatus main body 10 is provided with a paper feed tray that stores recording paper as a recording medium, a paper feed roller that carries out the recording paper from the paper feed tray, and the like. Further, a conveyance path R for guiding the recording paper upward from the paper feed tray is formed in the image forming apparatus main body 10. In the transport path R, a pair of timing rollers 21 for measuring the transport timing of the recording paper is disposed on the way from the position where the paper feed roller is disposed to the position where the secondary transfer roller 17 is disposed. Yes.

  A fixing device 22 for fixing the image on the recording paper is disposed on the left side of the position where the secondary transfer roller 17 is disposed. Further, on the left side of the fixing device 22, a pair of paper discharge rollers 24 are provided for discharging the recording paper to a stock portion formed by denting the upper surface of the image forming apparatus main body 10.

(Operation of image forming apparatus)
The basic operation of the image forming apparatus will be described below with reference to FIG. When the image forming operation is started, the photosensitive drums 2 of the process units 1Y, 1M, 1C, and 1Bk are rotationally driven counterclockwise by a driving device (not shown), and the surface of each photosensitive drum 2 is charged by a charging device 3 is uniformly charged to a predetermined polarity.

  The surface of each charged photoconductive drum 2 is irradiated with laser light or LED light from the exposure device 8, and an electrostatic latent image is formed on the surface of each photoconductive drum 2. At this time, the image information to be exposed on each photosensitive drum 2 is single-color image information obtained by separating a desired full-color image into color information of yellow, magenta, cyan, and black. The electrostatic latent image formed on the photosensitive drum 2 in this manner is supplied with toner by each developing device 4 so that the electrostatic latent image is developed (visualized) as a toner image.

  One of the support rollers 12 to 15 (support roller 13) that stretches the intermediate transfer belt 11 is rotationally driven, so that the intermediate transfer belt 11 travels in the direction indicated by the arrow in the figure (clockwise). Further, a constant voltage having a polarity opposite to the charging polarity of the toner or a voltage controlled by a constant current is applied to each primary transfer roller 16.

  As a result, a transfer electric field is formed in the primary transfer nip between each primary transfer roller 16 and each photosensitive drum 2. The toner images of the respective colors formed on the photosensitive drums 2 of the process units 1Y, 1M, 1C, and 1Bk are sequentially superimposed and transferred onto the intermediate transfer belt 11 by the transfer electric field formed in the primary transfer nip. Is done.

  Thus, the intermediate transfer belt 11 carries a full-color toner image on its surface. Further, a lubricant is applied to the surface of each photoreceptor drum 2 after the transfer of the toner image by the lubricant application device 6, and then the toner remaining on the surface of each photoreceptor drum 2 is removed by the cleaning device 5. The

  When the image forming operation is started, the paper feed roller starts rotating, and the recording paper stored in the paper feed tray is sent out to the transport path R. The recording sheet sent to the conveyance path R is temporarily stopped by the timing roller 21. Thereafter, the driving of the timing roller 21 is resumed, and the recording paper is sent to the secondary transfer nip between the secondary transfer roller 17 and the intermediate transfer belt 11 in synchronization with the toner image on the intermediate transfer belt 11. It is done.

  At this time, a transfer voltage having a polarity opposite to the toner charging polarity of the toner image on the intermediate transfer belt 11 is applied to the secondary transfer roller 17, thereby forming a transfer electric field in the secondary transfer nip. When the recording paper and the toner image on the intermediate transfer belt 11 reach the secondary transfer nip, the toner image on the intermediate transfer belt 11 is collectively put on the recording paper by the transfer electric field formed in the secondary transfer nip. And transferred.

  Further, the toner remaining on the intermediate transfer belt 11 after the transfer is removed by the belt cleaning device 18. The recording sheet on which the toner image is transferred is conveyed to the fixing device 22 where the toner image is fixed on the recording sheet. Thereafter, the recording paper is discharged to the stock section by the paper discharge roller 24.

  The above description is an image forming operation when a full-color image is formed on a recording sheet. A similar operation is to form a single color image using any one of the four process units 1Y, 1M, 1C, or 1Bk, or use two or three process units for two or three colors. Even when an image is formed.

(Process unit configuration)
FIG. 2 is a schematic configuration diagram of the process units 1Y, 1M, 1C, and 1Bk. As shown in FIG. 2, a charging device 3 is disposed above the photosensitive drum 2, a developing device 4 is disposed on the left side, a lubricant applying device 6 is disposed on the right side, and a cleaning device 5 is disposed below the charging device 3.

  The charging device 3 includes a contact-type charging roller 45 as a charging member disposed to face the photosensitive drum 2. The charging roller 45 can be in contact with the photosensitive drum 2 to suppress generation of ozone. The charging roller 45 may be opposed to the photosensitive drum 2 with a small gap, whereby dirt such as toner from the photosensitive drum 2 is less likely to adhere to the surface of the charging roller 45. It is possible to suppress the dirt and extend its life.

  The charging roller 45 performs AC charging with the AC voltage superimposed on the DC voltage on the photosensitive drum 2. By performing AC charging, the charging current flows sufficiently and the influence of fluctuations in the charging potential due to minute gap fluctuations is suppressed, and the image carrier charging potential is stabilized by uniform charging, resulting in high-quality images. can get.

  The developing device 4 includes a developing case 40 that contains a developer, and a developing roller 47 that is rotatably supported by the developing case 40 and that faces the photosensitive drum 2 through an opening formed in the developing case. Have Further, a transport screw 43 that transports the developer in the developing case 40 to the developing roller 47 is provided. As the developer, a two-component developer having a toner and a carrier, or a one-component magnetic toner or a one-component non-magnetic toner having no carrier can be used.

  The lubricant application device 6 scrapes the solid lubricant 33 with an application roller 30 as a lubricant application member and applies it to the photosensitive drum 2, and is unitized in the case 32. The application roller 30 can be in the form of, for example, a brush roller in which fine fibers are radially planted around the rotation axis, or in the form of a sponge roller, and both ends of the rotation axis are supported by the case 32.

Then, the powder of the lubricant scraped off from the solid lubricant 33 is caused to adhere to the peripheral surface of the photosensitive drum 2 that is in rotational contact by the rotation of the application roller 30. The material of the application roller 30 was adjusted to a volume resistivity of 1 × 10 ³ Ωcm or more and 1 × 10 ⁸ Ωcm or less by adding a resistance control material such as carbon black to a resin such as nylon or acrylic. Material can be used.

  The lubricant application device 6 can have various configurations as will be described later. Here, the basic operation of the process unit 1 including the lubricant application device 6 will be described, and the detailed operation of each lubricant application device 6 will be described later.

  The cleaning device 5 includes a cleaning blade 52 and a waste toner collection coil 53. The cleaning blade 52 has a function of removing residual toner on the photosensitive drum 2. The waste toner collecting coil 53 conveys the removed toner to a waste toner bottle (not shown).

(Process unit operation)
Next, the operation of the process units 1Y, 1M, 1C, and 1Bk will be described with reference to FIG. When the image forming operation is started, the photosensitive drum 2 is rotated counterclockwise in FIG. 2, and at this time, the photosensitive drum 2 is charged to a predetermined polarity by the charging roller 45 to which a charging voltage is applied.

  Thereafter, the electrostatic latent image on the photosensitive drum 2 formed by exposure from the exposure device 8 moves to a position facing the developing roller 47, where toner is supplied from the developing roller 47 to the electrostatic latent image.

  Specifically, after the developer carried on the developing roller 47 that rotates clockwise in FIG. 2 is regulated to a predetermined thickness by a developing blade (not shown), the developing area between the developing roller 47 and the photosensitive drum 2 is determined. Carried to. Here, the toner in the developer is electrostatically transferred to the electrostatic latent image on the photosensitive drum 2, and the electrostatic latent image is visualized as a toner image. The toner image on the photosensitive drum 2 moves to a lower position of the photosensitive drum 2 and is transferred to the intermediate transfer belt 11 here.

  After the toner image is transferred, lubricant powder is applied to the surface of the photosensitive drum 2 by the application roller 30 that rotates clockwise in FIG. The lubricant powder layer is spread to a uniform thickness by the application blade 50 on the downstream side to form a protective layer on the surface of the photosensitive drum 2. Since the protective layer is very thin, charging by the charging device 3 is not hindered. As a result, it is possible to realize an image forming apparatus that does not cause an abnormal image due to contamination of the charging roller 45, reduces the frequency of replacement of consumables, and can output high-quality images over a long period of time.

(Lubricant application device)
As shown in detail in FIGS. 3A to 3D, the lubricant application device 6 includes a rod-like lubricant holding member 31 disposed in the case 32 and a rod-like solid lubricant 33. The solid lubricant 33 is slightly shorter than the lubricant holding member 31 and is held on the lubricant holding member 31 via a fixing means such as a double-sided tape. A pressurizing spring 37 as a pressurizing unit that pressurizes the solid lubricant 33 toward the application roller 30 is disposed in a space between the lubricant holding member 31 and the bottom plate of the case 32 below the lubricant holding member 31. A pair of right and left pressure arms 34 connected to both ends of the pressure spring 37 and urged in a closing direction by the pressure spring 37 are provided.

  The left and right pressurizing arms 34 are disposed at symmetrical positions with respect to the longitudinal center of the lubricant holding member 31, and are supported by the lubricant holding member 31 so as to be rotatable about a support shaft 34a. The pressure spring 37 is attached while being stretched between the left and right pressure arms 34. Due to the tensile force of the pressure spring 37, the left and right pressure arms 34 press the lubricant holding member 31 equally to the left and right toward the application roller 30, and the solid lubricant 33 is applied to the outer peripheral surface of the application roller 30 with a predetermined pressure. Surface contact.

  As shown in FIGS. 3A to 3D, one end portion in the longitudinal direction of the lubricant holding member 31 constitutes an extended portion 31 a that extends in the longitudinal direction. The extended portion 31a includes the same plane as the lower end support surface of the solid lubricant 33 (the same level in height), and passes through the longitudinal hole 32a as an opening formed in the end side wall of the case 32, and extends outside the case 32. It extends to. The gap between the vertically long hole 32a and the extension portion 31a is made as small as possible within a range that does not hinder the upward movement of the lubricant holding member 31 so that the powder of the solid lubricant 33 is not scattered outside.

  Since the extension portion 31a cannot move above the upper end portion of the vertically long hole 32a, when the solid lubricant 33 is replaced, the lubricant holding member 31 unexpectedly jumps out by the force of the pressure spring 37 and is solid. It is possible to prevent the lubricant 33 from being damaged. The configuration of the extension part 31a and the vertically long hole 32a does not increase the number of parts, and the part shape is simple, so that the cost can be reduced.

  On the outside of the case 32, a fixed contact 35a and a movable contact 35b of the electric resistance detection means 35 are provided as detection means capable of detecting the movement of the extension 31a to a predetermined position at a position overlapping the movement range of the extension 31a. Has been. The fixed contact 35a and the movable contact 35b are formed by conductive leaf springs having substantially the same size, and the fixed contact 35a is fixedly arranged in a lateral direction at a height close to the upper end portion of the vertically long hole 32a. The fixed contact 35a and the movable contact 35b are connected to the terminal of the electrical resistance detection means 35 by wiring, and the change in electrical resistance (conductive or non-conductive) between the fixed contact 35a and the movable contact 35b is the electrical resistance detection means. 35 is detected.

  The movable contact 35b is disposed substantially parallel to the fixed contact 35a with a slight gap below the fixed contact 35a. The base end portion of the movable contact 35b is fixed to the case 32 or the like, and the tip end portion is elastically movable in the vertical direction (the moving direction of the extension portion 31a).

  When the lubricant holding member 31 rises from the state shown in FIG. 4A to the state shown in FIG. 4B as the solid lubricant 33 is consumed, the extension 31a bends the tip of the movable contact 35b upward, and the tip Is configured to contact the fixed contact 35a. As described above, since the upper surface of the extension portion 31a is at the same level as the lower end of the solid lubricant 33, it is possible to accurately detect the end of life when the remaining height of the solid lubricant 33 is equal to or less than a predetermined height.

  The lubricant application device 6 is configured as described above. As shown in FIG. 4A, when the solid lubricant 33 is new, the solid lubricant 33 has a sufficient height, and the lubricant holding member 31 is a case. In the lower position in 32. In this state, the movable contact 35b is separated from the fixed contact 35a, and the electrical resistance detection means 35 does not detect the conduction between the contacts 35a and 35b. Therefore, in this state, power consumption is not generated in the electrical resistance detection means 35, and energy saving of the apparatus can be achieved.

  When the solid lubricant 33 is consumed, the lubricant holding member 31 is pushed up by the force of the pressurizing spring 37 as shown in FIG. 4B, and moves parallel to a high position in the case 32. As a result, the movable contact 35b is bent upward by the extension 31a, and the tip of the movable contact 35b comes into contact with the fixed contact 35a. That is, the movable contact 35b and the fixed contact 35a are electrically connected, and the change in the electrical resistance between the two contacts is detected by the electrical resistance detection means 35. By this detection, the life of the solid lubricant 33 is detected, and the detection signal is transmitted to the drive system of the photosensitive drum 2 through the CPU of the control device of the image forming apparatus. Then, the rotation of the photosensitive drum 2 is stopped and the image forming operation is stopped.

  Simultaneously with the stop of the image forming operation or after a certain period of time, a display for prompting the user to replace the solid lubricant 33 can be displayed on the liquid crystal display device of the operation panel of the image forming apparatus. Alternatively, it is possible to notify the service person in charge of the image forming apparatus of the time for replacement of the solid lubricant 33 by communication means using the web or the like.

  Since the fixed contact 35a and the movable contact 35b of the electrical resistance detection means 35 are disposed outside the case 32, the contact can be prevented from being contaminated with the powder of the solid lubricant 33. Therefore, it is possible to prevent a conduction failure due to the dirt. As shown in FIG. 3D, the electrical resistance detection means 35 may be covered with a protective cover 36 having a vertically long hole 36a for inserting the extension portion 31a.

  FIG. 5A shows a second embodiment of the lubricant application device, and the base portion of the extended portion 31a at one end of the lubricant holding member 31 is a narrowed constricted portion 31b. The constricted portion 31 b is inserted into the vertically long hole 32 a of the case 32. The vertically long hole 32a is formed so as to be displaced with respect to the distal end side of the extension portion 31a as shown in FIG. 5B.

  That is, the position is shifted in a direction perpendicular to the approaching / separating direction of the lubricant holding member 31 with respect to the application roller 30 (the direction perpendicular to the paper surface of FIG. 5B). For this reason, even if the powder of the solid lubricant 33 leaks from the vertically long hole 32a, the powder is difficult to reach the movable contact 35b and the fixed contact 35a. Therefore, it is possible to more effectively prevent the occurrence of poor conduction due to contamination of the movable contact 35b and the fixed contact 35a.

(Lubricant life detection considering the travel distance of the application roller)
FIGS. 6A to 6C illustrate an example in which the travel distance of the application roller is detected by a second detection unit (not shown) and the life of the solid lubricant is detected in consideration of the travel distance. In addition, referring to the same drawing, how to set the timing for closing the movable contact 35b and the fixed contact 35a of the electrical resistance detecting means 35 will be described together.

  The above-described life detection of the solid lubricant 33 is less waste as the remaining amount of the solid lubricant 33 at the time of life detection is smaller. However, the life detection does not always operate normally due to malfunction of the electrical resistance detection means 35 or the like. Therefore, in addition to the above-described detection of the life of the solid lubricant 33, solid life is also considered in consideration of conventional life determination based on the usage status of the lubricant application device 6 such as the travel distance of the application roller 30 on the photosensitive drum 2. The life or replacement time of the lubricant 33 may be determined.

  On the other hand, the lubricant application device 6 is required to stably apply a necessary amount of lubricant to the photosensitive drum 2. When the coating amount is large, the friction coefficient on the surface of the photosensitive drum 2 becomes too low. As a result, the amount of toner carried on the photosensitive drum 2 is reduced, and an abnormal image called a worm-eaten image or the like is formed. If the coating amount is small, problems such as photoconductor filming occur due to an increase in the coefficient of friction and insufficient protective action of the photoconductor drum 2 resulting therefrom.

  Normally, the amount of lubricant applied is set to be an appropriate amount when an image with an image area ratio of about 3% to 10%, which is a normal image for office use, is formed by the pressure of the pressure spring 37 or the like. (Adjustment of the amount of lubricant applied may be carried out depending on the rotation speed and rigidity of the application roller). Here, [image area ratio] = [image area] / [traveling area]. [Image area] = [count pixel count] × [area of one pixel]. [Traveling area] = [traveling distance] × [imaging width]. [Travel distance] = [photosensitive drum count rotation speed] × [photosensitive drum circumference] or [travel distance] = [photosensitive drum count rotation time] × [photosensitive drum linear speed]) . Therefore, the second detection means can be easily configured by a part of the control device of the image forming apparatus main body that detects the count rotation number of the photosensitive drum, for example.

  When the contact area between the application roller 30 and the surface of the photosensitive drum is large, the amount of solid lubricant applied increases, and the charging roller becomes dirty. On the other hand, when the contact area between the application roller and the surface of the photosensitive drum is small, the solid lubricant is insufficiently applied, and photoconductor filming or the like due to insufficient photoconductor protection action occurs (from JP 2012-177866 A).

  However, even if the lubricant application amount is set corresponding to the predetermined use condition of the image forming apparatus, the actual use condition differs for each user of the apparatus. For this reason, in consideration of the variation between the image forming apparatuses, the lubricant application amount is often set to the worst condition side (the condition side where the consumption amount is large). In this case, if the life of the solid lubricant 33 is determined based on the travel distance of the application roller 30 as in the conventional case, the user who uses the apparatus under the use conditions such as the low image area ratio, replaces the lubricant application unit. Time is earlier than necessary. In this case, the lubricant application unit must be replaced before the solid lubricant 33 mounted on the apparatus is fully used, which is contrary to the recent demand for resource saving and the like.

  Therefore, a lubricant application device having a detecting means for detecting that the remaining amount of lubricant is reduced as in Patent Documents 1 and 2 described above has been proposed. By detecting the actual remaining amount of lubricant, it is possible to reliably replace the lubricant application unit when the remaining amount of lubricant falls below a certain level even if the user's usage conditions differ. it can. Thereby, it is possible to eliminate the waste of the lubricant due to the early replacement of the unit, etc., and at the same time, it is possible to prevent the occurrence of the trouble due to the exhaustion of the lubricant.

  Returning to FIGS. 6A to 6C again, the detection timing of the electrical resistance detection means 35 will be described. FIG. 6A shows a state where the solid lubricant 33 is new. In this state, the height of the lubricant is A0. Also, as shown in FIG. 6B, the height at the near end of life is A1. In this case, as shown in FIG. 6C, under normal use conditions, the height of the solid lubricant 33 is linearly proportional to the travel distance of the application roller 30 on the peripheral surface of the photosensitive drum 2 from A0 to A1. To decrease.

  As shown in FIGS. 6A and 6B, the above-described lubricant life detection device uses the electrical resistance detection means 35 to lubricate the lubricant when the lubricant height (A 0) reaches a certain height (A 1). Detect that the remaining amount is in a near-life state. Based on the detection, the image forming operation is stopped, or the service life and replacement of the solid lubricant 33 are notified to the user and service personnel. However, with this detection method, the remaining amount of the solid lubricant 33 cannot be estimated at all until the lubricant reaches a certain height (A1).

  In a use condition where the required amount of lubricant on the photosensitive drum 2 is small, such as a low image area ratio, the transition of the decrease in the lubricant height is small (in the direction in which the downward sloping in FIG. 6C becomes gentle). Under such usage conditions, a part of the scraped lubricant powder is not applied to the photosensitive drum 2 and easily accumulates in the case 32. Further, the lubricant is deposited on the application roller 30 itself, and the application roller 30 is covered with the lubricant, and the amount of lubricant scraped by the application roller 30 is also reduced. If the powder of the solid lubricant 33 accumulated in the case 32 adheres to the contact point of the electric resistance detecting means 35, there is a possibility that a conduction failure may occur, and there is a situation where the device is continuously driven without noticing the depletion of the solid lubricant 33. Can occur. Therefore, in order to prevent the occurrence of such a situation, it is desirable to count the travel distance of the application roller 30 in combination with the electrical resistance detection means 35.

  In FIG. 6C, B1 is a threshold value of the travel distance of the application roller 30 when used at a low image area ratio. The solid lubricant 33 can be used until the threshold is reached. When the counted travel distance exceeds the threshold value, if the electrical resistance detection means 35 is not yet operated, the electrical resistance detection means 35 may be malfunctioning. Therefore, in such a case, for example, it may be possible to give a warning to the user to request confirmation of the remaining amount of the solid lubricant 33. Moreover, it can also be displayed in steps from several days ago that the replacement timing of the solid lubricant 33 is approaching from the counted travel distance.

  After the travel distance B1 at the near end of life, the image forming operation for a certain period is performed with a threshold (Bt) such as a predetermined travel distance starting from B1 as a limit, and then the final life of the photosensitive drum 2 is reached. Disable machine operation such as drive. The travel distance Bt of the application roller 30 from the near end of life to the end of end of life can be calculated relatively accurately from the rotational speed of the photosensitive drum 2 and the like.

  6D and 6E show flowcharts for determining “near life” and “life”. In step S1 of FIG. 6D, it is determined whether or not the above-described electrical resistance detection means 35 has detected conduction. If the electrical resistance detection means 35 has not detected continuity, it is determined in step S2 whether or not the travel distance of the application roller 30 is greater than or equal to B1. When B1 or more, the user is notified in step S3 that the lubricant has a near life. Thereafter, the flow proceeds to the flow of FIG. 6E. If it is less than B1, the determinations in steps S1 and S2 are repeated periodically until it is determined that it is greater than or equal to B1. If the electrical resistance detection means 35 detects continuity, the process immediately proceeds to step S3 and the above processing is performed.

  In step S4 of FIG. 6E, it is determined whether the travel distance of the coating roller 30 after the near end of life is equal to or longer than Bt. If it is greater than or equal to Bt, the user is notified in step S5 that the lubricant is at the end of its life, and at the same time, a signal is sent to the CPU of the control device of the image forming apparatus so as to prohibit subsequent machine operations. If it is less than Bt, the determination in step S4 is repeated periodically until it is determined that it is greater than or equal to Bt.

  The electric resistance detection means 35 is preferably set so as to operate earlier by a predetermined travel distance of the application roller 30 than the period of Bt. As a result, even when the electrical resistance detector 35 malfunctions as described above, the “near life” and “life” of the lubricant can be reliably detected based on the travel distance, and the lubricant is depleted. Can be prevented. Even if the electrical resistance detecting means 35 is operated within the Bt period, the machine operation is disabled as described above without extending the Bt period.

  The near life detection can be detected not only by the travel distance of the application roller 30 but also by counting the rotation time of the application roller 30 and the like. However, since the rotation speed of the application roller 30 may be controlled according to environmental fluctuations such as the ambient temperature of the image forming apparatus, the travel distance of the application roller 30 is counted for accurate life prediction. It is desirable to do.

(Circuit configuration of detection means)
FIG. 7A shows a circuit configuration in which contacts 35 a and 35 b provided on both sides of the lubricant holding member 31 are connected in parallel to one electrical resistance detecting means 35. In this circuit configuration, the left and right contacts 35a and 35b are detected without distinction.

  In FIG. 7B, the contact points 35a and 35b provided on both sides of the lubricant holding member 31 are independently detected by one electrical resistance detection means 35. Since the solid lubricant 33 may be consumed in a biased manner in the left-right direction depending on use, even if the lubricant height at the left or right end of the solid lubricant 33 has reached the near end of life, The lubricant may not have reached the near life. In such a case, the circuit configuration of FIG. 7B can inform the user of the uneven wear state of the solid lubricant 33. The solid lubricant 33 that is worn out evenly can be used in such a way that its life is extended by switching the left and right sides.

  The electrical resistance detection means 35 used in the present invention is not limited to the conduction detection type using the fixed contact 35a and the movable contact 35b. For example, the electrical resistance detection means 35 may be replaced with a push switch 55 having an actuator 55a that can be pressed by the extension 31a as shown in FIGS. 8A and 8B. As the push switch 55, a dust-proof type can be used, and malfunction due to lubricant powder can be more effectively prevented.

  Further, as shown in FIGS. 9A and 9B, the electric resistance detection means 35 may be replaced with a photo interrupter 65. The photo interrupter 65 can be disposed on a vertical surface where powder is difficult to adhere as shown in FIG. 9C. The extension part 31a functions as a filler, and the life of the solid lubricant 33 can be reliably detected by light shielding by the extension part 31a.

  Examples of the solid lubricant 33 include fatty acids such as lead oleate, zinc oleate, copper oleate, zinc stearate, cobalt stearate, iron stearate, copper stearate, zinc halmitate, copper halmitate, and zinc linoleate. Metal salts can be used. Further, as the solid lubricant 33, a material obtained by applying zinc stearate, calcium stearate, or the like to a solid molded body can also be used.

  The solid lubricant 33 contains at least a fatty acid metal salt, and particularly contains zinc stearate, so that the effect of protecting the image carrier and reducing the cleaning defect can be particularly increased. The solid lubricant 33 includes at least an inorganic lubricant, and in particular, boron nitride. In particular, the solid lubricant 33 can increase the cleaning blade deterioration deterioration effect, the charging roller deterioration deterioration effect, and the cleaning defect reduction effect. it can. When the solid lubricant 33 is a lubricant containing both a fatty acid metal salt and an inorganic lubricant, the deterioration over time of the image carrier and the peripheral parts of the image carrier can be improved together, and the solid lubricant 33 includes the image carrier. A great effect is obtained in improving the life of peripheral components.

  The solid lubricant 33 is generally soft and it is difficult to maintain the shape in the longitudinal direction by itself. Accordingly, a reinforcing member having a predetermined rigidity is interposed between the solid lubricant 33 and the lubricant holding member 31 as necessary, or the rigidity of the lubricant holding member 31 itself is increased, so that the lubricant holding member 31 is It may function as a reinforcing member.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. For example, in the above description, the solid lubricant 33 is pressed against the application roller 30 by the pressure spring 37, but the solid lubricant 33 may be pressed against the application roller 30 by its own weight without using the pressing means. .

  In the above-described embodiment of the present invention, the case where the present invention is applied to the lubricant applying device 6 that applies the lubricant to the photosensitive drum 2 has been described as an example. However, the transfer body such as an intermediate transfer belt is lubricated. It is also possible to apply the present invention to an apparatus for applying an agent. Alternatively, the present invention can also be applied to an apparatus for applying a lubricant to an application object other than the photosensitive drum and the transfer body.

  In addition to directly operating the detection means at the extension 31a of the lubricant holding member 31, one or more intermediate members are connected to the extension 31a and the detection means is operated at the end member of the intermediate member. It may be configured. In this case, by further separating the detection means from the lubricant housing case, it is possible to more effectively prevent the conduction failure due to the adhesion of the detection means to the dirt. The intermediate member can have various configurations such as a lever mechanism using a rotating member and a parallel link mechanism.

  Further, the intermediate member can amplify the amount of operation of the detection means relative to the amount of movement of the lubricant holding member. For example, the distance between two normal contact points of the detection means can be widened to depend on the dimensional accuracy and placement accuracy of the parts. The influence due to the variation in the distance between the contacts can be minimized.

  Further, the image forming apparatus provided with the lubricant applying device according to the present invention is not limited to the color image forming apparatus shown in FIG. 1, but may be a monochrome image forming apparatus, a copying machine, a printer, a facsimile, or a complex machine thereof. May be. In addition, although the application roller 30 is rotated in the forward direction (trailing direction) with respect to the rotation direction of the photosensitive drum 2 as shown in FIG. 2, it may be rotated in the opposite counter direction.

1Y, 1M, 1C, 1Bk: Process unit 2: Photosensitive drum (coating object)
3: Charging device 4: Developing device 5: Cleaning device 6: Lubricant coating device 8: Exposure device 9: Transfer device 10: Image forming device body 11: Intermediate transfer belt 16: Primary transfer roller 17: Secondary transfer roller 18: Belt cleaning device 21: Timing roller 22: Fixing device 24: Paper discharge roller 30: Application roller 31: Lubricant holding member 31a: Extension portion 31b: Constricted portion 32: Case 32a: Long hole (opening)
33: Solid lubricant 34: Pressurizing arm 34a: Support shaft 35: Electric resistance detection means (detection means)
35a: fixed contact 35b: movable contact 36: protective cover 36a: vertically long hole 37: pressure spring 40: developing case 43: conveying screw 45: charging roller 46: charging cleaning roller 47: developing roller 48: developing blade 50: cleaning blade 51: Waste toner collecting coil 55: Push switch 65: Photo interrupter

JP-A-8-314346 Japanese Patent No. 3406999

Claims (14)

An application roller that rotates and contacts the surface of the object to be applied to apply a solid lubricant;
A lubricant holding member disposed so as to be movable toward and away from the application roller while holding a solid lubricant arranged in contact with the application roller;
A case housing the application roller and a lubricant holding member;
An extension that is disposed at an end of the lubricant holding member in the longitudinal direction and extends to the outside of the case from an opening formed in the case;
Detecting means disposed on the outside of the case and capable of detecting movement of the extension portion to a predetermined position accompanying consumption of the solid lubricant;
A lubricant application device having   The lubricant application device according to claim 1, wherein the application operation by the application roller is stopped by detecting the movement of the extension portion to a predetermined position by the detection means.   The lubricant application device according to claim 1, wherein the opening and the detection unit are disposed so as to be shifted in a direction perpendicular to the approaching / separating direction of the lubricant holding member.   In addition to the detection means, there is provided second detection means for detecting the travel distance of the application roller on the surface of the application object, and when the predetermined travel distance is detected by the second detection means, the detection means causes the The lubricant application device according to claim 2, wherein the application operation by the application roller is stopped even before the extension portion is detected.   The detection means is disposed within the movement range of the extension portion of the lubricant holding member and operates when the extension portion hits, a fixed contact with which the movable contact contacts, and a fixed contact with the movable contact 2. The lubricant application device according to claim 1, further comprising an electric resistance detecting means for detecting an electric resistance between the contacts.   The lubricant application device according to claim 1, wherein the detection unit includes a push switch that is disposed within a movement range of the extension portion of the lubricant holding member and includes an actuator that operates when the extension portion hits.   The lubricant application device according to claim 1, wherein the detection unit includes a filler disposed in an extension portion of the lubricant holding member and a photo interrupter disposed in a movement range of the filler.   The lubricant application device according to claim 5, wherein an intermediate member for transmitting the movement of the extension portion to the movable contact is disposed between the extension portion and the movable contact.   The lubricant application device according to claim 8, wherein the intermediate member includes a lever, and the movement of the extension portion is expanded by the lever and transmitted to the movable contact.   The extension is disposed at both ends of the lubricant holding member, the movable contact and the fixed contact are disposed on both the left and right sides of the case, and one electric resistance is detected on the left and right movable contacts and fixed contacts. 6. The lubricant application device of claim 5, wherein the means are connected in parallel.   The extension is disposed at both ends of the lubricant holding member, the movable contact and the fixed contact are disposed on both the left and right sides of the case, and two electric resistance detections are performed on the movable contact and the fixed contact on both the left and right sides. 6. The lubricant application device of claim 5 wherein the means are connected separately.   The lubricant application device according to any one of claims 1 to 11, further comprising a pressurizing unit that pressurizes the lubricant holding member toward the application roller.   An image carrier that carries an image, and a lubricant application device according to any one of claims 1 to 12 that applies a lubricant to the image carrier, and is detachable integrally with the image forming apparatus main body. Process unit configured to.   An image forming apparatus comprising the process unit according to claim 13.

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