JP2018004715A - Image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and appropriately determine the life of a photoreceptor when forming a toner image on a surface of the photoreceptor by causing a toner to convey a developer containing a lubricant and removing the toner remaining on the surface of the photoreceptor after transfer of the toner image by a cleaning member.SOLUTION: The image formation device includes: a charging device 11 for charging the surface of a photoreceptor 10 having a photosensitive layer 10a; a developing device 30 for forming a toner image by causing a toner to convey a developer D containing a lubricant along the axial direction of the photoreceptor and then supplying the toner from a developer carrier 32 to the surface of the photoreceptor; a cleaning member 16a for removing the toner remaining on the surface of the photoreceptor after transferring the toner image; a film thickness detection device 40 for detecting the thickness of the photosensitive layer of the photoreceptor for the downstream side of the developer in the conveyance direction; and a life determination device 50 for determining the life of the photoreceptor based on the thickness of the photosensitive layer detected by the film thickness detection device.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, and a multifunction machine of these. In particular, a rotating photosensitive member on which a photosensitive layer is formed, a charging device for charging the surface of the photosensitive member on which the photosensitive layer is formed, and a developer containing a lubricant in toner in the axial direction of the photosensitive member by a conveyance supply member. And a developing device that forms a toner image by supplying toner from the developer carrying member to the surface of the photosensitive member and transferring the toner image formed on the surface of the photosensitive member. In an image forming apparatus provided with a cleaning member that removes toner remaining on the surface of the body, the life of the photoreceptor can be easily and appropriately determined.

  Conventionally, in an image forming apparatus such as a copying machine or a printer, a photosensitive member having a photosensitive layer formed on the surface thereof is rotated, and the surface of the photosensitive member having the photosensitive layer formed thereon is charged by a charging device. A latent image corresponding to image information is formed on the surface of the photosensitive member, and toner is supplied to the latent image portion from a developing device to form a toner image on the surface of the photosensitive member.

  The toner image thus formed on the surface of the photoconductor is transferred to a recording medium such as a recording sheet or an intermediate transfer body such as an intermediate transfer belt, and then a cleaning blade or the like is cleaned on the surface of the photoconductor. The member is brought into contact, and the toner remaining on the surface of the photoreceptor is removed from the surface of the photoreceptor by the cleaning member.

  Here, when the cleaning member is brought into contact with the surface of the photosensitive member as described above and removed from the surface of the toner photosensitive member remaining on the surface of the photosensitive member, the photosensitive layer formed on the surface of the photosensitive member. However, the photosensitive member is gradually scraped by the cleaning member, so that proper image formation cannot be performed. Therefore, the photoconductor is replaced with a new one.

  Conventionally, in order to prevent the photosensitive layer on the surface of the photoreceptor from being scraped by the cleaning member, toner containing a lubricant is used as the developer in the developing device, and the toner containing the lubricant is supplied to the surface of the photoreceptor. Then, after the toner image is transferred from the photosensitive member to a recording medium or an intermediate transfer member, a cleaning member is brought into contact with the surface of the photosensitive member to remove the toner remaining on the surface of the photosensitive member. In removing the lubricant, the lubricant is held between the cleaning member and the surface of the photosensitive member to prevent the frictional resistance between the cleaning member and the surface of the photosensitive member from increasing.

  Further, as described above, when detecting that the photosensitive layer on the surface of the photosensitive member has been scraped by the cleaning member and the photosensitive member has reached the end of its life, conventionally, when forming an image by rotating the photosensitive member, The number of rotations of the photosensitive member and the number of image formations are counted, and thereby the amount of wear of the photosensitive layer by the cleaning member is predicted to detect whether the photosensitive member has reached the end of its life.

  However, when the number of rotations of the photosensitive member and the number of image formations are counted and the amount of wear of the photosensitive layer by the cleaning member is predicted to detect whether the photosensitive member has reached the end of its life, the photosensitive layer formed on the photosensitive member Depending on the state, image forming conditions, and the like, the difference between the detected photosensitive layer thickness and the actual photosensitive layer thickness may become large, and the lifetime of the photoreceptor cannot be accurately determined.

  In addition, when the surface of the photosensitive member is charged by a charging roller, the current flowing from the contact charging member such as a charging roller to the photosensitive member is detected, and the film thickness of the photosensitive layer is detected from the amount of change in the current. Yes.

  However, in this case, although the film thickness of the photosensitive layer in the entire axial direction of the photoconductor can be detected, the film thickness of the photosensitive layer in each position in the axial direction of the photoconductor cannot be properly detected. Since the thick and thin portions of the photosensitive layer are formed during the manufacture of the photoreceptor, the thin portion of the photosensitive layer is deteriorated first, and the life of the photoreceptor is accurately determined. I could not.

  Further, in Patent Document 1, when the end portion and the center portion of the photoconductor are exposed and the end portion and the center portion of the exposed photoconductor are charged by the contact charging member, the current flowing through these portions is changed. It has been proposed to detect the thickness of the photosensitive layer at the end and the center of the photoreceptor.

  Further, in Patent Document 2, since the amount of abrasion of the photosensitive layer by the cleaning member differs between the portion where the toner image is formed and the portion where the toner image is not formed, at a plurality of different positions in the axial direction of the photoreceptor. It has been proposed to detect the film thickness of the photosensitive layer and perform the depletion operation when the difference in the film thickness of the photosensitive layer in the portions having different axial positions exceeds a predetermined reference value.

  However, in both Patent Documents 1 and 2, the film thickness of the photosensitive layer is detected at a plurality of positions, and the lifetime of the photoreceptor is determined based on the difference in film thickness of the photosensitive layer at each detection position. For this reason, there is a problem that the work becomes troublesome and it is necessary to provide a plurality of sensors or the like with respect to one photoconductor, resulting in high cost.

JP-A-8-202220 JP2015-166820A

  The present invention provides a rotating photosensitive member having a photosensitive layer formed thereon, a charging device for charging the surface of the photosensitive member having the photosensitive layer formed thereon, and a developer containing toner and a lubricant as a toner. A developing device that transports the toner along the direction and supplies the toner in the developer from the developer carrying member to the surface of the photoconductor to form a toner image, and the toner image formed on the surface of the photoconductor is transferred An object of the present invention is to make it possible to easily and appropriately determine the life of a photoconductor in an image forming apparatus provided with a cleaning member that removes toner remaining on the surface of the photoconductor later.

  In the image forming apparatus of the present invention, in order to solve the above-described problems, a rotating photosensitive member on which a photosensitive layer is formed, a charging device for charging the surface of the photosensitive member on which the photosensitive layer is formed, and a toner And a developer supplying the developer along the axial direction of the photoconductor, and supplying the toner in the developer from the developer carrier to the surface of the photoconductor to form a toner image. And a cleaning member that removes toner remaining on the surface of the photoconductor after the toner image formed on the surface of the photoconductor is transferred, and the developer is conveyed by the conveyance supply member. Based on the film thickness detecting device for detecting the film thickness of the photosensitive layer on the photoconductor facing the downstream portion of the developer conveying direction, and the film thickness of the photosensitive layer detected by the film thickness detecting device. It provided the lifetime determination device for determining the life of the photoreceptor.

  Here, in the image forming apparatus according to the present invention, as in the developing device, the developer containing the lubricant in the toner is transported along the axial direction of the photosensitive member by the transport supply member and the toner in the developer is carried by the developer. When a toner image is formed by supplying from the surface to the surface of the photoconductor, the lubricant is generally supplied from the developer carrier to the surface of the photoconductor regardless of the toner image, and the developer is transported by the transport and supply member. As the sheet moves from the upstream side to the downstream side, the amount of lubricant supplied from the developer carrying member to the surface of the photosensitive member decreases, and the frictional force between the photosensitive member and the cleaning member increases upstream in the developer conveying direction. It increases as it goes from the side toward the downstream side, and the wear amount of the photosensitive layer on the downstream side in the developer transport direction increases. For this reason, as described above, the film thickness detecting device detects the film thickness of the photosensitive layer on the photoconductor facing the downstream portion of the developer in the conveyance direction in which the developer is conveyed by the conveyance supply member, and based on this result. Thus, when the lifetime of the photoconductor is determined by the lifetime determination device, the lifetime of the photoconductor can be appropriately detected.

  In the image forming apparatus according to the present invention, when the film thickness of the photosensitive layer is detected by the film thickness detector, a toner image is formed by applying a predetermined charge application voltage from the charging device to the photoconductor. The film thickness of the photosensitive layer can be detected based on the toner image.

  In the image forming apparatus according to the present invention, when the film thickness of the photosensitive layer is detected by the film thickness detector, the film thickness of the photosensitive layer on the photoconductor is determined by the film thickness detector according to the usage time of the photoconductor. When to detect the thickness can be determined.

  In the image forming apparatus according to the present invention, when the film thickness detecting device detects the film thickness of the photosensitive layer, the toner image is formed on the photoconductor according to the print coverage of the toner image. Thus, the timing for detecting the film thickness of the photosensitive layer in the photoconductor can be determined by the film thickness detector.

  Further, in the image forming apparatus according to the present invention, a plurality of the photoconductor, the charging device, the developing device, and the cleaning member are provided, and an intermediate transfer to which a toner image formed on each photoconductor is transferred. And a density sensor for detecting the toner density of each toner image transferred from each photoconductor to the intermediate transfer body, and each toner image transferred from each photoconductor detected by the density sensor to the intermediate transfer body. Based on the toner density, the film thickness detection device can detect the film thickness of the photosensitive layer in each photoconductor.

  Further, in the image forming apparatus, the toner image is transferred sequentially from each photosensitive member to the intermediate transfer member, and the film thickness detecting device detects the film thickness of the photosensitive layer in each photosensitive member. It is preferable that the number of times of detecting the film thickness of the photosensitive layer on the photosensitive member positioned upstream in the moving direction of the intermediate transfer member is larger than that in the photosensitive member positioned downstream in the moving direction of the intermediate transfer member. This is because when the lubricant is supplied to the intermediate transfer member from the photosensitive member located on the upstream side in the movement direction of the intermediate transfer member, the lubricant thus supplied is transferred to the photosensitive member located on the downstream side in the movement direction of the intermediate transfer member. The amount of lubricant supplied to the photoconductor located downstream in the moving direction of the intermediate transfer member is larger than that of the photoconductor positioned upstream in the moving direction of the intermediate transfer member, and the intermediate transfer member The frictional force between the photosensitive layer and the cleaning member in the photosensitive member located downstream in the moving direction of the intermediate transfer member is reduced, and the photosensitive layer in the photosensitive member located upstream in the moving direction of the intermediate transfer member is downstream in the moving direction of the intermediate transfer member. This is because the cleaning member is more worn by the cleaning member than the photosensitive layer in the photosensitive member located at the position.

  In the image forming apparatus, a toner image is formed by supplying a toner containing a lubricant from each developing device corresponding to each photoconductor, and the film thickness of the photosensitive layer on each photoconductor is formed by the film thickness detecting device. , The number of times of detecting the film thickness of the photosensitive layer can be varied in accordance with the amount of lubricant contained in the toner used in the developing device.

  In the image forming apparatus according to the present invention, as described above, the thickness of the photosensitive layer on the photoreceptor facing the downstream side of the developer transport direction in which the developer is transported by the transport supply member, and the photosensitive layer is abraded much. Since the film thickness is detected by the film thickness detector, and based on the result, the life of the photoconductor is judged by the life judging device, so that the life of the photoconductor can be detected easily and appropriately.

In the image forming apparatus according to an embodiment of the present invention, a state in which toner images are formed on a plurality of photoconductors, and the toner images formed on the photoconductors are sequentially transferred to an intermediate transfer belt to form an image. It is the shown schematic explanatory drawing. In the image forming apparatus according to the above-described embodiment, toner is supplied from the developing device to the photoconductor to form a toner image on the photoconductor, and the toner image formed on the photoconductor is transferred to the intermediate transfer belt, while the transfer is performed. FIG. 6 is a schematic explanatory view showing a state in which toner remaining on the surface of the subsequent photoreceptor is removed by a cleaning member. In the image forming apparatus according to the above-described embodiment, the developer accommodated in the developing device is conveyed along the axial direction of the photosensitive member by the conveying and supplying member, and the toner in the developer is transferred from the developer carrying member to the photosensitive member. When the toner is supplied to the toner, a toner image is formed on the photoreceptor at a position downstream of the developer conveyance direction, and the film thickness of the photosensitive layer on the photoreceptor is detected by the film thickness detector based on the toner density of the toner image. In addition, it is a schematic explanatory view showing a state in which the life of the photosensitive member is judged by the life judging device. In the image forming apparatus according to the above-described embodiment, the developer conveyance direction with respect to each of the four photoconductors is set to the same direction, and toner density detection is performed on each of the four photoconductors at a position downstream of the developer conveyance direction. Form a toner pattern image, transfer each toner pattern image to the intermediate transfer belt, and detect the film thickness provided on one side in the width direction of the intermediate transfer belt based on the toner density of each toner pattern image transferred to the intermediate transfer belt FIG. 3 is a schematic explanatory diagram illustrating a state in which the thickness of a photosensitive layer in each photoconductor is detected by an apparatus and the lifetime of each photoconductor is determined by a lifetime determination device. In the image forming apparatus according to the above-described embodiment, for each of the four photoconductors, the direction in which the developer is conveyed is changed in order so as to be in the reverse direction, and at each position downstream of the developer conveyance direction, A toner pattern image for detecting the toner density is formed on each of the four photoconductors, each toner pattern image is transferred to the intermediate transfer belt, and an intermediate density is determined based on the toner density of each toner pattern image transferred to the intermediate transfer belt. Schematic explanatory diagram showing a state in which the film thickness of the photosensitive layer in each photoconductor is detected by the corresponding film thickness detection devices provided on both sides in the width direction of the transfer belt, and the life of each photoconductor is determined by the life determination device It is.

  Next, an image forming apparatus according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. Note that the image forming apparatus according to the present invention is not limited to those shown in the following embodiments, and can be implemented with appropriate modifications within a range not changing the gist thereof.

  In the image forming apparatus according to this embodiment, as shown in FIG. 1, four photoreceptors 10 having photosensitive layers 10 a formed on the surface are arranged, and each photoreceptor 10 is associated with the interior of the apparatus main body 31. Four developing devices 30 containing the developer D are provided, and each developing device 30 uses toners of yellow, magenta, cyan, and black with different toner colors in the developer D, respectively. Each of these toners contains a lubricant such as zinc stearate.

  In this image forming apparatus, each of the photosensitive members 10 is rotated, and the surface of each of the photosensitive members 10 on which the photosensitive layer 10a is formed is charged by the charging device 11, respectively. The latent image forming device 12 exposes the body 10 in accordance with the image formation information to form an electrostatic latent image on the surface of each photoreceptor 10.

  Then, the developer D accommodated in the apparatus main body 31 is guided from the corresponding developing device 30 to the surface of each photoconductor 10 on which the electrostatic latent image is formed in this manner by the rotating developer carrier 32. Each toner of a predetermined color in the developer D is supplied to the electrostatic latent image of each photoconductor 10 to perform development, and a toner image of each color is formed on the surface of each photoconductor 10. .

  Next, the surface of the intermediate transfer belt (intermediate transfer member) 14 in the form of an endless belt that is rotated around the rotation roller 13 by rotating the toner images of the respective colors formed on the respective photosensitive members 10 as described above. In addition, primary transfer is sequentially performed by primary transfer rollers 15 provided to face the respective photoreceptors 10 to form a full-color toner image on the surface of the intermediate transfer belt 14.

  Further, as described above, the cleaning member 16 a provided in the first cleaning device 16 is brought into contact with the surface of each photoconductor 10 after the toner image is transferred to the intermediate transfer belt 14. The toner remaining on the surface of each photoconductor 10 is removed.

  The full-color toner image formed on the surface of the intermediate transfer belt 14 as described above is guided to a position facing the secondary transfer roller 17 by the intermediate transfer belt 14.

  On the other hand, the recording sheet S accommodated in the lower part of the image forming apparatus is fed by the sheet feeding roller 18 and sent to the timing roller 19, and the recording sheet S is fed by the timing roller 19 to the intermediate transfer belt 14 and the secondary transfer roller 17. The toner image formed on the surface of the intermediate transfer belt 14 is transferred to the recording sheet S by the secondary transfer roller 17.

  Further, the cleaning member 20 a provided in the second cleaning device 20 is brought into contact with the surface of the intermediate transfer belt 14 after the toner image is transferred to the recording sheet S, and the toner remaining without being transferred to the recording sheet S is contacted. The cleaning member 20a removes the intermediate transfer belt 14 from the surface.

  Then, the recording sheet S to which the toner image is transferred as described above is guided to the fixing device 21, and the transferred toner image is fixed on the recording sheet S by the fixing device 21. The recording sheet S on which the toner image is fixed is discharged by a discharge roller 22.

  Note that the image forming apparatus according to the present invention is not limited to the above, and although not shown, each developing device is sequentially moved by rotating a rotary developing device holding a plurality of developing devices. It may be a full-color image forming apparatus that forms a full-color image so as to be guided to a photoreceptor, or an image forming apparatus that forms a monochrome image.

  Here, in the developing device 30, as shown in FIGS. 2 and 3, the developer carrier 32 that rotates as described above faces the photoconductor 10 along the axial direction of the photoconductor 10. In addition, a transport supply member 33 is provided along the axial direction of the photoconductor 10 in the developer supply transport section 31 a located on the opposite side of the photoconductor 10 via the developer carrier 32 in the apparatus main body 31. The transport supply member 33 is rotated so that the developer D containing the lubricant in the toner as described above is supplied to the developer carrier 32 while being transported along the developer carrier 32 by the transport supply member 33. I have to.

  Further, a transport circulation member 35 is provided along the axial direction of the photoreceptor 10 in the developer circulation transport section 31b on the opposite side of the photoreceptor 10 through the developer supply transport section 31a and the partition wall 34. Is rotated so that the developer D is transported in the developer circulation transport unit 31b, and the developer D is passed through the circulation ports 34a provided at both ends of the partition wall 34, and the developer supply transport unit 31a and the developer. It is made to circulate and convey between the circulation conveyance part 31b.

  In the developing device 30, as described above, the developer D in the developer supply transport unit 31 a is supplied to the developer carrier 32 while being transported along the developer carrier 32 by the transport supply member 33. In the middle of transporting the developer D supplied to the developer carrier 32 to a position facing the photoconductor 10, the amount of developer D that is transported is regulated by the regulating member 36, and the amount is regulated in this way. The developed developer D is guided to a position facing the photoreceptor 10 by the developer carrier 32, and the toner in the developer D is supplied to the electrostatic latent image formed on the photosensitive layer 10a of the photoreceptor 10 as described above. Then, a toner image is formed on the surface of the photoconductor 10, and the toner image thus formed on the surface of the photoconductor 10 is transferred to the intermediate transfer belt 14 as described above. Toner remaining on the surface Followed by removal from the surface of the photoconductor 10 by the cleaning member 16a.

  Here, when the developer D containing the lubricant in the toner is supplied from the developer carrier 32 to the surface of the photoreceptor 10 as described above to form a toner image, the lubricant is transferred from the developer carrier 32 to the photoreceptor 10. The amount of lubricant supplied from the developer carrier 32 to the surface of the photoconductor 10 decreases as the developer D is moved from the upstream side to the downstream side in the transport direction by the transport supply member 33 and the surface of the photoconductor 10 is decreased. 10 and the cleaning member 16a increase from the upstream side in the transport direction of the developer D toward the downstream side, and the wear amount of the photosensitive layer 10a on the downstream side in the transport direction of the developer D increases. .

  For this reason, in the example shown in FIG. 3, when detecting the life of the photosensitive member 10, the developer supply member 33 conveys the developer D by the conveyance supply member 33 and faces the portion of the developer carrier 32 on the downstream side in the conveyance direction of the developer D. In this position, the film thickness of the photosensitive layer 10a on the photoconductor 10 is detected by the film thickness detection device 40, and the life of the photoconductor 10 is determined by the life determination device 50 based on the detection result.

  Here, as a method of detecting the film thickness of the photosensitive layer 10a in the photoconductor 10 by the film thickness detection device 40, for example, the surface potential of the photoconductor 10 to be charged is changed by the change in the film thickness of the photoconductive layer 10a. Then, a predetermined charging voltage can be applied to form a toner image on the surface of the photoconductor 10, and the toner density of this toner image can be detected to detect the film thickness of the photosensitive layer 10a.

  When the film thickness detecting device 40 detects the film thickness of the photosensitive layer 10a in the photoconductor 10 and the life determining device 50 determines the life of the photoconductor 10, for example, the usage time of the photoconductor 10 is used. Accordingly, the timing for detecting the photosensitive layer 10a in the photoconductor 10 is determined by the film thickness detection device 40, or the photoconductor is detected by the film thickness detection device 40 according to the print coverage of the toner image formed on the photoconductor 10. 10 can determine the timing of detecting the photosensitive layer 10a.

  Further, when the four photoconductors 10 are arranged as in the image forming apparatus according to the above-described embodiment, it is possible to provide the film thickness detection device 40 and the life determination device 50 corresponding to each photoconductor 10. However, in this case, a plurality of film thickness detection devices 40 and life determination devices 50 are required.

  For this reason, for example, as shown in FIG. 4, the transport direction (X) of the developer D that transports the developer D containing the lubricant to the toner by the transport supply member 33 is the same direction in each of the four photoreceptors 10. Then, toner pattern images tA to tD for toner density detection are respectively formed on the four photoconductors 10A to 10D at positions downstream in the transport direction (X) of the developer D, and thus each photoconductor 10A to 10D is formed. The toner pattern images tA to tD formed on 10D are transferred to the intermediate transfer belt 14, and the toner density of each of the toner pattern images tA to tD transferred to the intermediate transfer belt 14 is determined in the moving direction Y downstream of the intermediate transfer belt 14. The film thickness is detected by the film thickness detecting device 40 provided on the one side in the width direction of the intermediate transfer belt 14 corresponding to each of the toner pattern images tA to tD. The intelligent device 40 detects the film thickness of the photosensitive layer 10a in each of the photoconductors 10A to 10D, and based on the detection result, the life determination device 50 can determine the life of each of the photoconductors 10A to 10D. .

  Further, in this way, when the film thickness detection device 40 detects the film thickness of the photosensitive layer 10a in each photoconductor 10, and the life determination device 50 determines the life of the photoconductor 10, as described above. When the toner image is transferred from the toner to the intermediate transfer belt 14, the lubricant contained in the developer D is supplied from the photoconductor 10 to the intermediate transfer belt 14, and thus the lubricant supplied to the intermediate transfer belt 14 is The lubricant is supplied to the photosensitive member 10 on the downstream side in the moving direction (Y) of the intermediate transfer belt 14, and the lubricant supplied to the photosensitive member 10 is moved toward the downstream side in the moving direction (Y) of the intermediate transfer belt 14. It is thought that it will increase. In this case, the number of times the film thickness detection device 40 detects the film thickness of the photosensitive layer 10a on the photoconductor 10 is set to the movement direction of the intermediate transfer belt 14 from the downstream side in the movement direction (Y) of the intermediate transfer belt 14. (Y) It is preferable to increase the number of the photoreceptors 10 positioned on the upstream side.

  Further, as described above, toner containing a lubricant is supplied from each developing device 30 in correspondence with each photoconductor 10 to form a toner image, and the thickness of the photosensitive layer 10a in each photoconductor 10 is determined by the film thickness detecting device 40. When the amount of lubricant contained in the developer D in each developing device 30 is different, the film thickness detecting device 40 performs photosensitivity on the photoreceptor 10 in accordance with the amount of lubricant contained in the developer D. The number of times of detecting the thickness of the layer 10a can be varied. In this case, it is preferable to increase the number of times the film thickness of the photosensitive layer 10a is detected by the film thickness detection device 40 as the amount of lubricant contained in the developer D decreases.

  Further, in the case shown in FIG. 4, the transport direction (X) of the developer D for transporting the developer D containing lubricant in the toner is set to be the same in each of the four photoconductors 10 as described above. As shown in FIG. 5, the developer D transport direction (X) is sequentially changed with respect to the four photoconductors 10 so as to be reversed, and the developer D transport direction (X) downstream position. The toner pattern images tA and tC and the toner pattern images tB and tD for detecting the toner density are formed on the four photoconductors 10 respectively, and the toner pattern images tA and tC and the toner pattern images tB and tD are transferred to the intermediate transfer belt. The image can also be transferred to the positions on both sides corresponding to 14. In this case, as shown in the figure, the toner pattern images tA and tC, the toner pattern images tB and tB transferred to the positions on both sides of the intermediate transfer belt 14 on the downstream side in the moving direction (Y) of the intermediate transfer belt 14. Film thickness detectors 40 are provided at positions on both sides in the width direction of the intermediate transfer belt 14 corresponding to tD, and the toner pattern images tA transferred to the positions on both sides of the intermediate transfer belt 14 by the two film thickness detectors 40. , TC, and the toner density of the toner pattern images tB, tD are detected to detect the film thickness of the photosensitive layer 10a in each of the photoconductors 10A to 10D. It can be made to judge the lifetime of -10D.

10, 10A to 10D Photoconductor 10a Photosensitive layer 11 Charging device 12 Latent image forming device 13 Rotating roller 14 Intermediate transfer belt (intermediate transfer member)
15 Primary transfer roller 16 First cleaning device 16a Cleaning member 17 Secondary transfer roller 18 Feed roller 19 Timing roller 20 Second cleaning device 20a Cleaning member 21 Fixing device 22 Paper discharge roller 30 Developing device 31 Device body 31a Developer Supply / conveyance section 31b Developer circulation conveyance section 32 Developer carrier 33 Conveyance supply member 34 Partition 34a Circulation port 35 Conveyance circulation member 36 Restriction member 40 Film thickness detection device 50 Life determination device D Developer S Recording sheet X Conveyance of developer Direction Y Movement direction of intermediate transfer belt tA to tD Toner pattern image

Claims (7)

A rotating photoreceptor on which a photosensitive layer is formed, a charging device for charging the surface of the photoreceptor on which the photosensitive layer is formed, and a developer containing a lubricant in toner along the axial direction of the photoreceptor by a conveyance supply member. A developing device for transporting and supplying toner in the developer from the developer carrying member to the surface of the photoconductor to form a toner image; and after transferring the toner image formed on the surface of the photoconductor, In an image forming apparatus comprising a cleaning member that removes toner remaining on the surface,
A film thickness detection device that detects the film thickness of the photosensitive layer on the photoreceptor facing the downstream side of the developer in the conveyance direction for conveying the developer by the conveyance supply member;
A lifetime determination device that determines the lifetime of the photoreceptor based on the thickness of the photosensitive layer detected by the thickness detection device;
An image forming apparatus comprising:   The image forming apparatus according to claim 1, wherein the film thickness detection device forms a toner image by applying a predetermined charge application voltage from the charging device to the photosensitive member when detecting the film thickness of the photosensitive layer. An image forming apparatus for detecting a film thickness of a photosensitive layer based on a toner image formed.   3. The image forming apparatus according to claim 1, wherein the timing for detecting the film thickness of the photosensitive layer in the photoconductor is determined by the film thickness detecting device according to a usage time of the photoconductor. Image forming apparatus.   4. The image forming apparatus according to claim 1, wherein when the toner image is formed on the photoconductor to form an image, the film thickness detection device is configured in accordance with a print coverage of the toner image. An image forming apparatus characterized by determining a timing for detecting a film thickness of a photosensitive layer in a photoconductor.   5. The image forming apparatus according to claim 1, wherein a plurality of the photosensitive members, the charging device, the developing device, and the cleaning member are provided and formed on each photosensitive member. An intermediate transfer body to which the toner image is transferred, and a density sensor for detecting the toner density of each toner image transferred from each photoconductor to the intermediate transfer body, and an intermediate from each photoconductor detected by the density sensor. An image forming apparatus, wherein the film thickness detecting device detects the film thickness of a photosensitive layer in each photoconductor based on a toner density of each toner image transferred to a transfer body.   6. The image forming apparatus according to claim 5, wherein a toner image is sequentially transferred from each photosensitive member to the intermediate transfer member, and the film thickness of the photosensitive layer on each photosensitive member is detected by the film thickness detecting device. The number of times of detecting the film thickness of the photosensitive layer on the photoconductor positioned upstream in the moving direction of the intermediate transfer member is larger than that in the photoconductor positioned downstream in the moving direction of the intermediate transfer member. apparatus. 6. The image forming apparatus according to claim 5, wherein when the film thickness detecting device detects the film thickness of the photosensitive layer in each photoconductor, the amount of lubricant contained in the toner in the developer used in each developing device is determined. Correspondingly, the number of times of detecting the film thickness of the photosensitive layer by the film thickness detection device is varied.

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