Image forming apparatus
By applying a scraping agent to the image carrier and moving it in a back-and-forth motion across the seal member, the issue of deposits forming lumps is resolved, ensuring effective cleaning and preventing image defects.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- RICOH CO LTD
- Filing Date
- 2022-06-27
- Publication Date
- 2026-07-09
AI Technical Summary
Attachments such as paper dust adhere to the opposing portion of the seal member facing the image carrier, forming lumps that reattach to the surface and cause gaps between the cleaning member and the image carrier, leading to poor cleaning performance.
A scraping agent, such as toner, is applied to the image carrier to scrape off deposits on the seal member, and the image carrier is moved across the seal member in a back-and-forth motion to effectively remove adhering material.
This approach suppresses the growth of deposits into clumps, maintaining good cleaning performance and preventing image defects like black streaks.
Smart Images
Figure 0007887089000001 
Figure 0007887089000002 
Figure 0007887089000003
Abstract
Description
Technical Field
[0001] The present invention relates to an image forming apparatus.
Background Art
[0002] Conventionally, there is known an image forming apparatus including a cleaning device having an image carrier that carries a toner image, a cleaning member that cleans the surface of the image carrier, and a seal member that is located upstream of the cleaning member in the surface movement direction of the image carrier and suppresses leakage of removed matter removed by the cleaning member to the outside.
[0003] Patent Document 1 describes an apparatus that cleans the surface of an intermediate transfer belt as an image carrier with a cleaning blade as a cleaning member.
Summary of the Invention
Problems to be Solved by the Invention
[0004] Attachments such as paper dust may adhere to the opposing portion of the seal member that faces an image carrier such as an intermediate transfer belt. The attachments adhering to this opposing portion grow over time, form lumps, and reattach to the surface of the image carrier. The lumps of the reattached attachments are sandwiched between a cleaning member such as a cleaning blade and the image carrier, resulting in a gap and possibly causing poor cleaning.
Means for Solving the Problems
[0005] In order to solve the above problems, the present invention provides an image forming apparatus including a cleaning device having an image carrier that carries a toner image, a cleaning member that cleans the surface of the image carrier, and a seal member that is located upstream of the cleaning member in the surface movement direction of the image carrier and suppresses leakage of removed matter removed by the cleaning member to the outside. The sealing member is provided with a proximity mechanism that brings it relatively closer to the image carrier,A scraping agent is applied to the surface of the image carrier to scrape off any deposits adhering to the opposing portion of the sealing member that faces the surface of the image carrier, and the image carrier is moved across the surface so that the scraping agent on the image carrier moves back and forth across the opposing portion. Sometimes, the sealing member is brought closer to the image carrier. It is characterized by the following: [Effects of the Invention]
[0006] According to the present invention, the occurrence of cleaning defects can be suppressed. [Brief explanation of the drawing]
[0007] [Figure 1] A schematic diagram of the image forming apparatus according to this embodiment. [Figure 2] Schematic diagram of a belt cleaning device. [Figure 3] Flowchart of the operation to remove attached material. [Figure 4] Flowchart of the process for scraping off attached material. [Figure 5] A schematic diagram showing the configuration of Modification Example 1. [Figure 6] A flowchart showing a modified version of the scraping operation for adhering material. [Figure 7] A diagram illustrating another configuration example where the entrance seal is brought closer to the intermediate transfer belt. [Figure 8] A schematic diagram showing the configuration of modified example 2. [Figure 9] A schematic diagram showing an example of a full-color image forming apparatus using a horizontal transport intermediate transfer method. [Figure 10] A schematic diagram showing an example of a direct transfer type full-color image forming apparatus. [Modes for carrying out the invention]
[0008] Figure 1 is a schematic diagram of a color laser printer (hereinafter simply referred to as "printer"), which is an image forming apparatus according to this embodiment.
[0009] The printer shown in Figure 1 has four process units 10Bk, 10Y, 10M, and 10C located in the center of the printer body 100, which are detachably attached to the printer body 100. Each process unit 10Bk, 10Y, 10M, and 10C has the same configuration except that it contains different colored developers corresponding to the color separation components of a color image: black (Bk), yellow (Y), magenta (M), and cyan (C). Therefore, when there is no particular distinction in color, the designations such as Bk, Y, M, and C are omitted after the symbols of each component.
[0010] Each process unit 10 includes a photoreceptor 1 which is an image carrier, a charging roller 2 for charging the surface of the photoreceptor, a developing device 4, a cleaning device 7 for cleaning the surface of the photoreceptor, and the like. The photoreceptor 1 is a cylindrical drum.
[0011] The cleaning device 7 has a cleaning blade 6 that makes counter-contact with the photoreceptor 1. Cleaning is performed by scraping off the remaining toner on the photoreceptor 1 with the cleaning blade 6. In addition to the blade cleaning method, electrostatic methods such as electrostatic brush methods and electrostatic roller methods can also be installed.
[0012] Above each process unit 10, an exposure device 3 is provided, which is a latent image forming means for exposing the surface of each photoreceptor 1. The exposure device 3 includes a light source, a polygon mirror, an f-θ lens, a reflective mirror, etc., and is configured to irradiate the surface of each photoreceptor 1 with laser light L based on image data.
[0013] Below each process unit 10, an intermediate transfer belt 15, which serves as the transfer body, is provided. The intermediate transfer belt 15 is an endless belt and is stretched by a secondary transfer opposing roller 21, a cleaning backup roller 16, and a tension roller 20.
[0014] Examples of materials that can be used for the intermediate transfer belt 15 include PVDF (vinyl fluoride), ETFE (ethylene-tetrafluoroethylene copolymer), PI (polyimide), PC (polycarbonate), and TPE (thermoplastic elastomer). By dispersing conductive materials such as carbon black in these materials, an endless belt in the form of a resin film can be used as the intermediate transfer belt.
[0015] In this embodiment, the intermediate transfer belt 15 rotates in the direction indicated by the arrow in the figure by rotating the secondary transfer opposing roller 21 with a belt-driven motor. Furthermore, the tension roller 20 applies tension to the intermediate transfer belt 15 by applying pressure to both axial ends of the tension roller 20 with springs. The drive source for the process unit that drives the photoreceptor 1 and the drive source that rotates the secondary transfer opposing roller 21 can be independent or shared. However, it is common practice to simultaneously switch the drive of the black process unit and the secondary transfer opposing roller 21 ON / OFF. Therefore, to reduce the size and cost of the main unit, it is desirable to share the drive source for the black process unit and the drive source for the secondary transfer opposing roller 21.
[0016] The four primary transfer rollers 5 are either conductive sponge rollers or metal rollers (aluminum, SUS), and each roller sandwiches an intermediate transfer belt 15 between itself and each photoreceptor 1 to form a primary transfer nip. A primary transfer high-voltage power supply is connected to each primary transfer roller 5, and a primary transfer bias is applied from this high-voltage power supply to form a transfer field. When conductive sponge rollers are used for the primary transfer rollers 5, ion-conductive rollers (urethane + carbon dispersion, NBR, hydrin rubber) or electronically conductive rollers (EPDM) are used.
[0017] The secondary transfer roller 25 forms a secondary transfer nip by sandwiching the intermediate transfer belt 15 between it and the secondary transfer opposing roller 21. Similarly to the primary transfer roller 5, a secondary transfer high-voltage power supply is connected to the secondary transfer roller 25, and a predetermined secondary transfer bias is applied from this high-voltage power supply to form a transfer electric field.
[0018] There are two types of secondary transfer biases: the attractive transfer method and the repulsive transfer method. In the attractive transfer method, a positive bias is applied to the secondary transfer roller 25 and the secondary transfer opposing roller 21 is grounded to form a secondary transfer electric field. In the repulsive transfer method, a negative bias is applied to the secondary transfer opposing roller 21 and the secondary transfer roller 25 is grounded to form a secondary transfer electric field.
[0019] The secondary transfer roller 25 is a sponge roller, and an ion conductive roller (urethane + carbon dispersion, NBR, hydrin rubber), an electron conductive type roller (EPDM), etc. are used. Also, a secondary transfer cleaning unit for removing deposits such as toner adhering to the surface of the secondary transfer roller 25 may be provided.
[0020] Also, as the secondary transfer unit for secondarily transferring the toner image on the intermediate transfer belt to the transfer paper P as the recording medium, a belt method using a secondary transfer belt may be used. The secondary transfer belt is stretched between a driving roller and a tension roller that face the intermediate transfer belt with the secondary transfer belt sandwiched therebetween. The driving roller is applied with a secondary transfer bias.
[0021] The belt cleaning device 32 has a transfer cleaning blade 31 that makes counter-contact with the intermediate transfer belt 15. Cleaning is performed by scraping off the remaining toner on the intermediate transfer belt 15 with the transfer cleaning blade 31. Note that electrostatic methods such as electrostatic brush or electrostatic roller methods can also be installed instead of the blade cleaning method. However, in the case of electrostatic methods, a cleaning brush / roller to which bias is applied is placed instead of the transfer cleaning blade 31. As a result, depending on the usage of the image forming apparatus, it may be necessary to pre-charge the remaining toner, which has disadvantages such as increasing the size of the cleaning unit itself, requiring one or two additional high-voltage power supplies, and requiring extra operation for bias cleaning. Therefore, from the viewpoint of miniaturization, cost reduction, and ease of cleaning, the blade cleaning method is preferred.
[0022] On the other hand, the lower part of the printer body 100 is provided with a paper feed tray 22 that houses the transfer paper P as a recording medium, and a paper feed roller 23 that discharges the transfer paper P from the paper feed tray 22. Here, the recording medium includes not only plain paper, but also cardboard, postcards, envelopes, thin paper, coated paper (such as coated paper and art paper), tracing paper, OHP sheets, etc. It also has a manual feed slot 42 through which the transfer paper set in the manual feed tray is transported.
[0023] The printer body 100 is equipped with a transport path for transporting transfer paper P from the paper feed tray 22 or manual feed tray through a secondary transfer nip to the outside of the device. In this configuration, the paper feed follows a vertical path. In the transport path, upstream of the secondary transfer roller 25 in the transfer paper transport direction, a pair of registration rollers 24 is provided as a transport means for transporting the transfer paper P to the secondary transfer nip.
[0024] Furthermore, a fixing device 40 for fixing the unfixed image transferred to the transfer paper P is located downstream of the secondary transfer roller 25 in the transfer paper transport direction. The printer body 100 also includes a control unit 90 that controls the entire device. The control unit 90 consists of a CPU, RAM, and ROM, and controls the operation of various devices in the printer and performs various calculations based on the control program stored in the ROM.
[0025] The basic operation of a printer with the above configuration is as follows: When the image formation operation begins, each photoreceptor 1 in each process unit 10 is driven to rotate clockwise in the diagram by a drive device. A roller-shaped charging roller 2 is pressed against the surface of each photoreceptor 1, and the charging roller 2 rotates in accordance with the rotation of the photoreceptor 1. Then, by applying a DC voltage or a bias consisting of a DC voltage superimposed on an AC voltage to the charging roller 2 from a high-voltage power supply, the surface of the photoreceptor 1 is uniformly charged to a predetermined polarity by the charging roller 2.
[0026] Each charged photoreceptor 1 is illuminated with writing light from the exposure device 3, forming an electrostatic latent image on the surface of each photoreceptor 1. At this time, the image information exposed to each photoreceptor 1 is monochrome image information obtained by decomposing a desired full-color image into yellow, magenta, cyan, and black color information. This exposure process is performed using a laser beam scanner with a laser diode or an LED.
[0027] In this way, the electrostatic latent image formed on each photoreceptor 1 is exposed (made visible) as a toner image when toner, supported on the developing roller, is supplied by each developing device 4. During this developing process, a predetermined developing bias is applied to the developing roller of the developing device 4 from a high-voltage power supply.
[0028] Furthermore, when the image formation operation begins, the secondary transfer opposing roller 21 rotates counterclockwise in the figure, causing the intermediate transfer belt 15 to travel in a circular motion in the direction indicated by the arrow in the figure. Then, a predetermined transfer bias controlled by a constant voltage or constant current with the opposite polarity to the charge polarity of the toner is applied to each primary transfer roller 5. As a result, a transfer electric field is formed at the primary transfer nip between each primary transfer roller 5 and each photoreceptor 1.
[0029] Subsequently, as each photoreceptor 1 rotates, when the toner images of each color on the photoreceptor 1 reach the primary transfer nip, the transfer electric field formed at the primary transfer nip sequentially transfers the toner images on each photoreceptor 1 onto the intermediate transfer belt 15. In this way, a full-color toner image is carried on the surface of the intermediate transfer belt 15.
[0030] Furthermore, any toner on each photoreceptor 1 that could not be transferred to the intermediate transfer belt 15 is removed by the cleaning device 7. Subsequently, the surface of each photoreceptor 1 is destaticized by the static elimination device, and its surface potential is reset.
[0031] At the bottom of the printer body 100, the paper feed roller 23 starts rotating, and the transfer paper P is fed from the paper feed tray 22 into the transport path. The transfer paper P fed into the transport path is then sent to the secondary transfer nip by the registration roller pair 24 so as to coincide with the timing when the leading edge of the toner image on the surface of the intermediate transfer belt 15 reaches the secondary transfer nip between the secondary transfer roller 25 and the secondary transfer opposing roller 21. At this time, a transfer bias with the opposite polarity to the toner charging polarity of the toner image on the intermediate transfer belt 15 is applied to the secondary transfer roller 25, thereby forming a transfer electric field in the secondary transfer nip.
[0032] Subsequently, as the intermediate transfer belt 15 rotates, when the toner image on the intermediate transfer belt 15 reaches the secondary transfer nip, the transfer electric field formed at the secondary transfer nip transfers the toner image on the intermediate transfer belt 15 onto the transfer paper P all at once.
[0033] Furthermore, any remaining toner on the intermediate transfer belt 15 that was not transferred to the transfer paper P is removed by the belt cleaning device 32. The removed toner is transported through the toner transport path to a waste toner container 33 located between the intermediate transfer belt 15 and the paper feed tray 22, where it is collected.
[0034] The transfer paper P is separated from the intermediate transfer belt 15 by the curvature of the secondary transfer opposing roller 21 and transported to the fixing device 40, where the toner image on the transfer paper P is fixed to the transfer paper P by heat and pressure in the fixing device 40. The transfer paper P is then discharged from the device through the discharge port 41. In this way, the series of image forming processes in the printer according to this embodiment are completed.
[0035] Furthermore, the printer of this embodiment has a belt contact / separation mechanism that moves the intermediate transfer belt 15 toward and away from the photoreceptor 1 of process units other than the Bk color process unit. When forming a full-color image, the belt contact / separation mechanism is controlled so that the intermediate transfer belt 15 comes into contact with each photoreceptor 1. When forming a monochrome image, the belt contact / separation mechanism is controlled so that the intermediate transfer belt 15 moves away from the photoreceptor 1 of process units other than the Bk color process unit.
[0036] Figure 2 is a schematic diagram of the belt cleaning device 32. The belt cleaning device 32 has a storage case 32a for storing waste toner removed by the transfer cleaning blade 31. Inside this storage case 32a, there is a transport screw 35 for transporting the waste toner inside the storage case 32a to the outside of the belt cleaning device 32. In addition, the storage case 32a is fitted with an inlet seal 34, which is a sealing member that prevents the waste toner inside the storage case 32a from scattering out of the storage case 32a.
[0037] As shown in Figure 2, the inlet seal 34 is attached to the housing case 32a such that its leading edge is located downstream in the direction of movement of the intermediate transfer belt 15, allowing residual toner and other materials on the intermediate transfer belt to easily pass through the inlet seal 34.
[0038] When passing through the entrance seal 34, paper dust and residual toner on the intermediate transfer belt 15 may be stirred up and adhere to the portion 34a of the entrance seal 34 that faces the intermediate transfer belt 15. This residue F adhering to the portion 34a of the entrance seal 34 may grow over time and fall onto the intermediate transfer belt 15 in clumps. If these clumps of residue F become trapped between the transfer cleaning blade 31 and the intermediate transfer belt 15, a gap will be created between the transfer cleaning blade 31 and the intermediate transfer belt 15. As a result, residual toner may slip through this gap, leading to poor cleaning and potentially causing image stains such as black streaks.
[0039] Furthermore, if the intermediate transfer belt 15 between the inlet seal 34 and the secondary transfer opposing roller 21 is sloped downwards with respect to the tip of the inlet seal 34, clumps of deposits that fall onto the intermediate transfer belt 15 will roll down the intermediate transfer belt 15 and adhere to the transfer paper. These deposits are a mixture of residual transfer toner and paper dust, and the attachment of such clumps of deposits causes the transfer paper to become dirty.
[0040] Therefore, in this embodiment, a scraping pattern K is formed periodically, and this scraping pattern K scrapes off deposits on the opposing portion 34a of the inlet seal 34. The scraping pattern K is, for example, a superimposed solid image of Y, M, C, and Bk. This allows the height of the scraping pattern K from the surface of the intermediate transfer belt 15 to be increased, and deposits F at the position furthest from the intermediate transfer belt 15 on the opposing portion 34a of the inlet seal 34 can be scraped off by the toner acting as a scraping agent in the scraping pattern.
[0041] Furthermore, with the scraping pattern K moving in only one direction, the toner cannot sufficiently scrape off the deposits F adhering to the opposing portion 34a of the inlet seal 34. Therefore, in this embodiment, the endless movement of the intermediate transfer belt 15 is controlled so that the scraping pattern K moves back and forth over the opposing portion of the inlet seal 34.
[0042] The deposits F on the leading edge of the inlet seal 34 are scraped off by the toner in the untransferred toner image when the untransferred toner image is input to the belt cleaning device 32, such as when a jam occurs, and rarely grow into clumps. Also, as shown in Figure 2, the gap between the inlet seal 34 and the intermediate transfer belt 15 narrows as it approaches the leading edge. Therefore, if the scraping pattern K is moved to the leading edge of the inlet seal 34, the scraping pattern K may be leveled and its height may decrease. As a result, on the return stroke, the deposits F on the opposing portion 34a of the inlet seal 34 on the upstream side in the surface movement direction of the intermediate transfer belt 15 during image formation may not be scraped off by the scraping pattern K. Therefore, the range in which the opposing portion 34a of the inlet seal 34 of the scraping pattern K is moved back and forth may be from the center to the upstream end in the surface movement direction of the intermediate transfer belt 15 during image formation. This can suppress the decrease in the height of the scraping pattern K. Therefore, even on the return journey, the toner of the scraping pattern K can effectively remove deposits from the opposing portion 34a on the upstream side of the surface movement direction during image formation of the intermediate transfer belt 15 of the entrance seal 34.
[0043] By periodically forming a scraping pattern K in this manner, and periodically scraping off the deposits adhering to the opposing portion 34a of the entrance seal 34 with toner acting as a scraping agent, it is possible to suppress the growth of deposits adhering to the opposing portion 34a of the entrance seal 34 into clumps. This allows for the maintenance of good cleaning performance over time and also suppresses the occurrence of image stains such as black streaks.
[0044] Figure 3 is a flowchart illustrating the execution of the adhering material scraping operation. The control unit 90, which is the control means for the image forming apparatus shown in Figure 3, counts the number of printed sheets and adds the number of printed sheets produced in the image forming operation performed this time to the cumulative number of printed sheets stored in memory (S1, S2).
[0045] Then, when the cumulative number of printed sheets reaches a predetermined number (Y in S3), the control unit 90 performs a material scraping operation (S4), and after the scraping operation is completed, it resets the cumulative number of printed sheets stored in memory. As a result, the material scraping operation is performed every predetermined number of printed sheets, and the material F attached to the opposite portion 34a of the inlet seal 34 can be scraped off before it grows into a mass. In the above description, the material scraping operation is performed based on the cumulative number of printed sheets, but for example, the material scraping operation may be performed based on the travel distance of the intermediate transfer belt 15.
[0046] Figure 4 is a flowchart of the process for scraping off attached material. When the adhering material scraping operation is performed, first the control unit 90 forms a scraping pattern K on the intermediate transfer belt 15 (S11). The control unit 90 also starts a timer when the intermediate transfer belt 15 starts to drive and monitors whether the timer has reached a first specified time (S12). This first specified time is the time from when the intermediate transfer belt 15 starts to drive until the scraping pattern K reaches a predetermined position on the opposing portion 34a of the inlet seal 34.
[0047] When the timer reaches the first specified time (Yes in S12), the intermediate transfer belt 15 is rotated in the reverse direction (S13). As a result, the scraping pattern K on the intermediate transfer belt 15 moves in the reverse direction, and the scraping pattern K scrapes off the deposits F attached to the inlet seal 34 again. This causes the scraping pattern K to move back and forth across the opposing portion 34a of the inlet seal 34, effectively removing the deposits from the inlet seal 34.
[0048] When the reverse rotation time of the intermediate transfer belt 15 reaches the second specified time (Yes in S14), the intermediate transfer belt 15 is driven to rotate in the forward direction again (S15). As a result, the scraping pattern K and the adhering material F scraped off by the toner of the scraping pattern K are input to the transfer cleaning blade 31 and removed from the intermediate transfer belt 15. The second specified time is the time from the start of reverse rotation until the scraping pattern K passes the upstream end of the inlet seal 34 in the surface movement direction of the intermediate transfer belt 15 during image formation.
[0049] In this embodiment, the scraping pattern K is moved back and forth once across the opposing portion 34a of the inlet seal 34, but it may be moved back and forth multiple times. By moving it back and forth multiple times, the toner of the scraping pattern K can more effectively scrape off any deposits adhering to the opposing portion 34a of the inlet seal 34.
[0050] Furthermore, a mechanism for moving the secondary transfer roller 25 toward and away from the intermediate transfer belt 15 may be provided, so that the secondary transfer roller 25 is separated from the intermediate transfer belt 15 during the adhering material scraping operation. This suppresses the adhesion of toner from the scraping pattern K to the secondary transfer roller 25, thereby suppressing contamination of the secondary transfer roller 25.
[0051] Next, a modified example of this embodiment will be described.
[0052] [Example 1] Figure 5 is a schematic diagram showing the configuration of Modified Example 1. Modification 1 shown in Figure 5 involves rotating the belt cleaning device 32 during the adhering material scraping operation to bring the inlet seal 34 closer to the intermediate transfer belt 15. Specifically, the belt cleaning device 32 is rotatably supported on the printer body 100 by a support shaft 36, and a cam mechanism 37, acting as an approach mechanism, rotates the belt cleaning device 32 clockwise around the support shaft 36 as a pivot point. This allows the inlet seal 34 to approach the intermediate transfer belt 15. In the above description, the belt cleaning device 32 is rotated by a cam mechanism 37, but this is not the only method; known methods such as actuators can also be used.
[0053] As shown in Figure 5, by bringing the inlet seal 34 closer to the intermediate transfer belt 15 during the adhering material scraping operation, the contact pressure between the toner of the scraping pattern K and the opposing portion 34a of the inlet seal 34 can be increased. This allows for effective scraping of the adhering material F on the opposing portion 34a.
[0054] Alternatively, the operation of bringing the entrance seal 34 closer to the intermediate transfer belt 15 may be performed when the intermediate transfer belt 15 is rotated in the reverse direction. Figure 6 is a flowchart showing a modified version of the adhering material scraping operation. As shown in Figure 6, the intermediate transfer belt 15 is rotated forward for a first specified time until the scraping pattern K reaches a predetermined position on the opposite portion of the inlet seal 34, at which point the intermediate transfer belt is rotated in the reverse direction (S21-S23). The cam mechanism 37 is also driven to bring the inlet seal closer to the intermediate transfer belt (S24).
[0055] This allows the gap between the inlet seal 34 and the intermediate transfer belt 15 to be narrowed during the return movement of the scraping pattern K. During the forward movement of the portion 34a of the inlet seal 34 of the scraping pattern K, the height of the scraping pattern K is high, and it can effectively scrape off the adhering material F on the portion 34a. However, as described above, the gap between the inlet seal 34 and the intermediate transfer belt 15 narrows as it approaches the tip, so the scraping pattern K may be leveled and its height may decrease as it moves toward the tip of the inlet seal 34. Therefore, during the return movement of the scraping pattern K, the contact pressure between the scraping pattern K and the portion 34a of the inlet seal 34 decreases, and the scraping performance of the toner of the scraping pattern K may decrease compared to the forward movement.
[0056] However, when the intermediate transfer belt 15 is rotated in reverse, the inlet seal 34 is brought closer to the intermediate transfer belt 15, and by narrowing the gap between the inlet seal 34 and the intermediate transfer belt 15, the decrease in contact pressure with the opposing portion 34a during the return movement of the scraping pattern K can be suppressed. Therefore, the decrease in scraping performance during the return movement can be suppressed, and the adhering material F attached to the opposing portion 34a of the inlet seal can be scraped off effectively.
[0057] Then, when the scraping pattern K passes the upstream end of the intermediate transfer belt 15 in the direction of surface movement during image formation of the inlet seal 34, the reverse rotation time of the intermediate transfer belt 15 becomes the second specified time. When the second specified time is reached, the cam mechanism 37 rotates the belt cleaning device 32 counterclockwise as shown in Figure 5. As a result, the inlet seal 34 moves away from the intermediate transfer belt 15, and the belt cleaning device 32 returns to the cleaning position (S26). As a result, the contact state of the transfer cleaning blade 31 with the intermediate transfer belt 15 can be returned to a contact state that allows for good cleaning of the intermediate transfer belt 15.
[0058] Then, once the belt cleaning device 32 returns to its cleaning position, the intermediate transfer belt 15 is driven to rotate in the forward direction again. As a result, the scraping pattern K and the adhering material F scraped off by the toner of the scraping pattern K are input to the transfer cleaning blade 31 and removed from the intermediate transfer belt 15.
[0059] The approaching movement of the entrance seal 34 during the return movement of the scraping pattern K may be controlled to gradually bring the entrance seal 34 closer to the intermediate transfer belt 15. By gradually bringing the entrance seal 34 closer to the intermediate transfer belt 15 in this way, the gap between the opposing portion 34a and the intermediate transfer belt 15 when scraping off deposits with the scraping pattern K can be made almost the same on the upstream and downstream sides in the surface movement direction of the intermediate transfer belt 15 during image formation. As a result, deposits on the opposing portion 34a can be uniformly scraped off in the surface movement direction of the intermediate transfer belt 15 during the return movement of the scraping pattern K.
[0060] Furthermore, as mentioned above, due to concerns about a decrease in the height of the scraping pattern K, it was preferable that the range in which the opposing portion 34a of the entrance seal 34 of the scraping pattern K is moved back and forth be from the center to the upstream end in the surface movement direction of the intermediate transfer belt 15 during image formation. However, by gradually bringing the entrance seal 34 closer to the intermediate transfer belt 15 during the return movement of the scraping pattern K, it is possible to move the scraping pattern K to the tip side of the entrance seal 34 and scrape off the attached material with the toner of the scraping pattern up to the tip side of the entrance seal 34 before reversing the rotation of the intermediate transfer belt 15, thereby suppressing a decrease in scraping performance during the return movement. This is because, during the return movement of the scraping pattern K, by gradually bringing the entrance seal closer to the intermediate transfer belt 15, the gap between the opposing portion 34a and the intermediate transfer belt 15 when scraping off attached material with the scraping pattern K can be made approximately the same as the gap between the tip of the entrance seal 34 and the intermediate transfer belt 15. Therefore, the toner of the scraping pattern K scrapes off the deposits up to the tip of the inlet seal 34, and even if the height of the scraping pattern decreases, the scraping pattern can be brought into contact with the upstream end of the opposing portion 34a during the return journey, allowing the scraping pattern to scrape off the deposits.
[0061] Furthermore, as shown in Figure 5, the inlet seal 34 is brought closer to the intermediate transfer belt 15 before the scraping pattern K enters the opposing portion 34a of the inlet seal 34. Then, as the opposing portion 34a of the scraping pattern K moves forward, the inlet seal 34 may be gradually moved away from the intermediate transfer belt. This makes it possible to keep the gap between the opposing portion 34a and the intermediate transfer belt 15 when the scraping pattern K scrapes off attached material approximately the same even when the scraping pattern K moves forward.
[0062] Furthermore, the configuration for bringing the inlet seal 34 closer to the intermediate transfer belt 15 is not limited to the configuration shown in Figure 5. For example, as shown in Figure 7, the entire belt cleaning device 32 may be configured to move in a direction perpendicular to the surface of the intermediate transfer belt 15, thereby bringing the inlet seal 34 closer to the intermediate transfer belt 15. Alternatively, for example, the inlet seal 34 may be provided so as to be movable within a predetermined range in a direction perpendicular to the surface of the intermediate transfer belt relative to the housing case 32a, and only the inlet seal 34 may be configured to move closer to the intermediate transfer belt. In addition, as described above, the belt cleaning device is moved to bring the inlet seal 34 closer to the intermediate transfer belt 15, but for example, the secondary transfer opposing roller 21 may be moved to the upper side of Figure 2 to bring the intermediate transfer belt 15 closer to the inlet seal 34.
[0063] [Differentiation 2] Figure 8 shows the configuration of modified example 2. As shown in Figure 8, in this modified example 2, the belt cleaning device 32 is equipped with a lubricant application device 50 on the upstream side of the intermediate transfer belt 15 in the surface movement direction, which applies lubricant to the intermediate transfer belt 15, and the lubricant from this lubricant application device 50 is used as a scraping agent to scrape off deposits adhering to the opposing portion of the inlet seal 34.
[0064] The lubricant application device 50, which serves as a scraping agent application device, is equipped with a rotatable application member, an application brush roller 51, and a solid lubricant 52. The lubricant application device 50 is also equipped with a pressure spring 53, which biases the solid lubricant toward the application brush roller 51, thereby pressurizing the solid lubricant 52 toward the application brush roller 51. The lubricant application device 50 is also equipped with a pressure adjustment mechanism 54 for adjusting the pressure applied by the solid lubricant 52 toward the application brush roller 51. The pressure adjustment mechanism 54 is equipped with a cam 54a and a cam motor 54b. The application brush roller 51 is rotationally driven by the drive motor 55, and as it rotates, the lubricant scraped from the solid lubricant 52 is applied to the intermediate transfer belt 15.
[0065] If the frictional force between the transfer cleaning blade 31 and the intermediate transfer belt 15 is too high, it may cause the free end of the transfer cleaning blade 31 to curl up, resulting in blade curling. It may also accelerate wear on the free end of the transfer cleaning blade 31 and the intermediate transfer belt 15, reducing their lifespan.
[0066] However, in the configuration of Modified Example 2, a lubricant application device 50 is provided to apply lubricant to the surface of the intermediate transfer belt 15. This reduces the frictional force between the intermediate transfer belt 15 and the transfer cleaning blade 31, suppressing the occurrence of peeling of the transfer cleaning blade 31 and reducing the lifespan of the transfer cleaning blade 31 and the intermediate transfer belt 15.
[0067] The lubricant application device 50 allows for adjustment of the amount of lubricant applied per unit time by adjusting the pressure applied to the application brush roller 51 by the pressure adjustment mechanism 54, or by adjusting the rotation speed of the application brush roller 51. When scraping off deposits F adhering to the inlet seal 34 with lubricant, the amount of lubricant applied per unit time is increased compared to normal, and the thickness of the lubricant layer applied to the intermediate transfer belt 15 is made thicker than usual.
[0068] Specifically, as described above, once the specified number of sheets is reached, the control unit 90 controls the drive motor 55 to increase the rotational speed of the application brush roller 51. The control unit 90 also controls the cam motor 54b to increase the biasing force of the pressure spring 53, thereby increasing the pressure applied to the application brush roller 51 by the solid lubricant 52. As a result, the amount of lubricant applied per unit time increases, and a scraping pattern is formed on the intermediate transfer belt 15 that is thicker than usual. Therefore, it becomes possible to scrape off deposits F adhering to the portion of the inlet seal 34a that is away from the intermediate transfer belt 15 and on the upstream side in the direction of movement of the intermediate transfer belt with the lubricant. Then, as described above, by moving this scraping pattern of lubricant back and forth, deposits F adhering to the inlet seal 34 are effectively scraped off with the lubricant.
[0069] In addition, depending on the configuration of the lubricant application device 50, it may not be possible to make the lubricant layer thick enough to contact the deposits on the upstream side of the surface movement direction of the intermediate transfer belt 15 during image formation, on the opposing portion 34a of the inlet seal 34. In this case, the configuration of Modification 1, in which the inlet seal 34 is brought closer to the intermediate transfer belt 15, can be adopted.
[0070] In addition, inorganic lubricants, fatty acid metal salts, waxes, etc., can be used as lubricants, but from the viewpoint of suppressing the lubricant itself from adhering to the inlet seal 34, it is preferable to use a wax with high adhesion resistance as the lubricant.
[0071] Furthermore, while the image forming apparatus shown in Figure 1 is a full-color image forming apparatus with a vertical transport intermediate transfer method that transports transfer paper vertically, the present invention can also be applied to a full-color image forming apparatus with a horizontal transport intermediate transfer method that transports transfer paper horizontally, as shown in Figure 9. The image forming apparatus shown in Figure 9 has five process units and can form toner images of black (Bk), yellow (Y), magenta (M), cyan (C), and spot color (S). Examples of spot color (S) toners include transparent toners such as IR (Infra-Red) toner, white toner, and fluorescent toner. In this image forming apparatus, it is possible to superimpose five solid color images as a scraping pattern, and it is possible to make the height of the scraping pattern higher. In this image forming apparatus, the scraping pattern scrapes off any material adhering to the inlet seal of the transfer belt cleaning device 132.
[0072] Furthermore, the present invention can also be applied to a direct transfer full-color image forming apparatus that directly transfers the toner image of each photoreceptor onto the transfer paper shown in Figure 10. This image forming apparatus shown in Figure 10 also has five process units and can form toner images of black (Bk), yellow (Y), magenta (M), cyan (C), and spot color (S). In this direct transfer full-color image forming apparatus, a scraping pattern K is formed on the transfer paper transport belt 70 to remove any deposits adhering to the inlet seal of the belt cleaning device 71 that cleans the transfer paper transport belt 70. The scraping pattern K, which is the toner image, is then carried on the transfer paper transport belt 70 and transported to the belt cleaning device 71. The scraping pattern then scrapes off any deposits adhering to the inlet seal of the belt cleaning device 71.
[0073] Furthermore, in Figures 9 and 10, the process unit furthest downstream in the belt movement direction among the five process units may be replaced with a special toner that has high scraping performance against deposits adhering to the inlet seal, instead of the special toner.
[0074] (Aspect 1) In an image forming apparatus, a cleaning device such as a belt cleaning device 32 has an image carrier such as an intermediate transfer belt 15 that carries a toner image, a cleaning member such as a transfer cleaning blade 31 that cleans the surface of the image carrier, and a sealing member such as an inlet seal 34 that is located upstream of the cleaning member in the direction of surface movement of the image carrier and prevents the removed material removed by the cleaning member from leaking to the outside, a scraping agent such as toner that scrapes off the material adhering to the opposing portion of the sealing member that faces the surface of the image carrier is applied to the surface of the image carrier, and the image carrier is moved across the surface so that the scraping agent on the image carrier moves back and forth across the opposing portion. For example, when a jam occurs, an untransferred toner image may be input to the cleaning device. Because such an untransferred toner image has a certain height from the surface of the image carrier, when it is input to the cleaning device, it may come into contact with deposits attached to the opposing part of the sealing member that is opposite the surface of the image carrier, and the deposits attached to the opposing part may be scraped off by the toner of the untransferred toner image. However, if the scraping agent such as toner moves in only one direction, there is a risk that the deposits attached to the opposing part may not be sufficiently scraped off. In contrast, in Embodiment 1, the scraping agent on the image carrier moves back and forth across the opposing portion of the sealing member that faces the image carrier. This allows the scraping agent to effectively scrape off any debris, such as paper dust, adhering to the opposing portion of the sealing member, compared to when the scraping agent moves in only one direction across the opposing portion. This effectively prevents the debris adhering to the opposing portion from growing over time, forming clumps, and re-adhering to the surface of the image carrier, thereby suppressing the occurrence of cleaning defects.
[0075] (Aspect 2) In embodiment 1, the image carrier is the intermediate transfer belt 15.
[0076] (Aspect 3) In embodiment 1 or 2, a proximity mechanism such as a cam mechanism 37 is provided to bring a sealing member such as an entrance seal 34 closer to an image carrier such as an intermediate transfer belt 15. According to this, as explained in Modification 1, when scraping off deposits by moving a scraping agent such as toner back and forth over an opposing part 34a such as an inlet seal 34, the approach mechanism such as a cam mechanism 37 can bring the sealing member closer to the image carrier. This increases the contact pressure between the scraping agent and the opposing part 34a, allowing the scraping agent to effectively scrape off deposits F adhering to the opposing part 34a.
[0077] (Aspect 4) In embodiment 3, the approach mechanism, such as the cam mechanism 37, rotates the cleaning device, such as the belt cleaning device 32, thereby bringing the sealing member, such as the entrance seal 34, closer to the image carrier, such as the intermediate transfer belt 15. According to this, sealing members such as the entrance seal 34 can be brought closer to the image carrier such as the intermediate transfer belt 15.
[0078] (Aspect 5) In embodiment 3, the approach mechanism moves a cleaning device such as a belt cleaning device 32 in a direction perpendicular to the surface of the image carrier such as an intermediate transfer belt 15, thereby bringing a sealing member such as an entrance seal 34 closer to the image carrier. According to this, as explained using Figure 6, sealing members such as the entrance seal 34 can be brought closer to the image carrier such as the intermediate transfer belt 15.
[0079] (Aspect 6) In any of embodiments 3 to 5, when the scraping agent such as toner on the image carrier, such as the intermediate transfer belt 15, is moved back and forth along the opposing portion 34a, a sealing member such as the entrance seal 34 is brought closer to the image carrier. According to this, as explained in Modification 1, the contact pressure between the scraping agent and the opposing portion 34a can be increased, and the adhering material F on the opposing portion 34a can be effectively scraped off by the scraping agent.
[0080] (Aspect 7) In any of embodiments 3 to 5, when the scraping agent on the image carrier, such as the intermediate transfer belt 15, moves the opposing portion 34a in the opposite direction to the direction of movement during image formation, the sealing member, such as the entrance seal 34, is brought closer to the image carrier. According to this, as explained in Modification 1, the decrease in contact pressure with the opposing portion 34a during the return movement of the scraping pattern can be suppressed. Therefore, the decrease in scraping performance during the return movement can be suppressed, and the adhering material F attached to the opposing portion 34a of the sealing member such as the inlet seal 34 can be scraped off effectively.
[0081] (Pattern 8) In any of embodiments 1 to 7, the scraping agent is toner. According to this, by forming a scraping toner image, such as a scraping pattern, on an image carrier such as an intermediate transfer belt 15 using a process unit 10 or the like, the scraping agent can be attached to the surface of the image carrier.
[0082] (Aspect 9) In embodiment 8, a scraping toner image, such as a scraping pattern K having a height that allows it to contact the opposing portion 34a of a sealing member such as an entrance seal 34, is formed on an image carrier such as an intermediate transfer belt 15, and the image carrier is moved across its surface so that the scraping toner image on the image carrier moves back and forth across the opposing portion 34a. According to this, as described in the embodiment, the deposits adhering to the opposing portion 34a can be effectively scraped off with toner.
[0083] (Aspect 10) In any of embodiments 1 to 7, a scraping agent application device is provided for applying a scraping agent to an image carrier such as an intermediate transfer belt 15. According to this, a scraping agent can be applied to the surface of the image carrier, such as the intermediate transfer belt 15.
[0084] (Aspect 11) In embodiment 10, the scraping agent application device is a lubricant application device that applies a lubricant to an image carrier such as an intermediate transfer belt 15. According to this, as explained in Modification 2, the surface of the image carrier is lubricated to suppress the reduction in the lifespan of cleaning members such as the transfer cleaning blade 31 and the image carrier, and the lubricant can scrape off any deposits adhering to the opposing portion 34a of sealing members such as the entrance seal 34.
[0085] (Aspect 12) In embodiment 11, the lubricant is wax. According to this, as explained in Modification 2, it is possible to suppress the lubricant from adhering to sealing members such as the inlet seal 34.
[0086] (Aspect 13) In any of embodiments 1 to 12, the scraping agent on the surface of the image carrier, such as the intermediate transfer belt 15, is moved back and forth multiple times. According to this, compared to applying a scraping agent such as toner to the opposing parts in one back-and-forth motion as described in the embodiment, the opportunities for scraping by the scraping agent can be increased, and the adhering material F attached to the opposing part 34a of the sealing member such as the inlet seal 34 can be effectively scraped off. [Explanation of Symbols]
[0087] 10: Process Unit 15: Intermediate transfer belt 16: Cleaning backup roller 21: Secondary transfer opposing roller 25: Secondary transfer roller 31: Transfer cleaning blade 32: Belt cleaning device 32a: Storage case 33: Waste Toner Container 34: Entrance Seal 34a: Opposing part 35: Conveyor Screw 36: Support shaft 37: Cam mechanism 70: Transfer paper conveyor belt 71: Belt cleaning device 90: Control Unit 100: Printer body 132: Transfer belt cleaning device F: Adhering substances K: Scraping pattern [Prior art documents] [Patent Documents]
[0088] [Patent Document 1] Japanese Patent Publication No. 2000-231280
Claims
1. An image carrier that holds the toner image, An image forming apparatus comprising a cleaning device having a cleaning member for cleaning the surface of the image carrier, and a sealing member located upstream of the cleaning member in the direction of surface movement of the image carrier, which prevents the removed material removed by the cleaning member from leaking to the outside, The sealing member is provided with a proximity mechanism that brings it relatively closer to the image carrier, An image forming apparatus characterized by applying a scraping agent to the surface of the image carrier, which scrapes off deposits adhering to the opposing portion of the sealing member that faces the surface of the image carrier, and bringing the sealing member closer to the image carrier when moving the image carrier across the surface so that the scraping agent on the image carrier moves back and forth across the opposing portion.
2. An image carrier that holds a toner image, An image forming apparatus comprising a cleaning device having a cleaning member for cleaning the surface of the image carrier, and a sealing member located upstream of the cleaning member in the direction of surface movement of the image carrier, which prevents the removed material removed by the cleaning member from leaking to the outside, The sealing member is provided with a proximity mechanism that brings it relatively closer to the image carrier, An image forming apparatus characterized in that, in an operation in which a scraping agent for scraping off deposits adhering to an opposing portion of the sealing member that faces the surface of the image carrier is applied to the surface of the image carrier, and the image carrier is moved across the surface such that the scraping agent on the image carrier moves back and forth across the opposing portion, the sealing member is brought closer to the image carrier when the scraping agent on the image carrier moves in the opposite direction to the direction of movement during image formation.
3. In the image forming apparatus according to claim 1 or 2, An image forming apparatus characterized in that the image carrier is an intermediate transfer belt.
4. In the image forming apparatus according to claim 1 or 2, The approach mechanism is characterized by bringing the sealing member closer to the image carrier by rotating the cleaning device.
5. In the image forming apparatus according to claim 1 or 2, The approach mechanism is characterized by moving the cleaning device in a direction perpendicular to the surface of the image carrier to bring the sealing member closer to the image carrier.
6. In the image forming apparatus according to claim 1 or 2, An image forming apparatus characterized by moving the scraping agent on the image carrier back and forth multiple times.
7. An image carrier that holds a toner image, An image forming apparatus comprising a cleaning device having a cleaning member for cleaning the surface of the image carrier, and a sealing member located upstream of the cleaning member in the direction of surface movement of the image carrier, which prevents the removed material removed by the cleaning member from leaking to the outside, An image forming apparatus characterized by forming a scraping toner image on the image carrier having a height that allows it to contact the opposing portion of the sealing member that faces the surface of the image carrier, and scraping off any deposits adhering to the opposing portion, and moving the image carrier across its surface so that the scraping toner image on the image carrier moves back and forth over the opposing portion.
8. In the image forming apparatus according to claim 7, An image forming apparatus characterized by moving the scraping toner image on the image carrier back and forth multiple times.
9. An image carrier that holds a toner image, An image forming apparatus comprising a cleaning device having a cleaning member for cleaning the surface of the image carrier, and a sealing member located upstream of the cleaning member in the direction of surface movement of the image carrier, which prevents the removed material removed by the cleaning member from leaking to the outside, The device includes a scraping agent application device for applying a scraping agent to the image carrier, which scrapes off any deposits adhering to the opposing portion of the sealing member that faces the surface of the image carrier. An image forming apparatus characterized by applying the scraping agent to the surface of the image carrier using the scraping agent application device, and moving the image carrier across its surface so that the scraping agent on the image carrier moves back and forth over the opposing portions.
10. In the image forming apparatus according to claim 9, The image forming apparatus is characterized in that the scraping agent application apparatus is a lubricant application apparatus for applying a lubricant to the image carrier.
11. In the image forming apparatus according to claim 10, The image forming apparatus is characterized in that the lubricant is wax.
12. In the image forming apparatus according to claim 9, An image forming apparatus characterized by moving the scraping agent on the image carrier back and forth multiple times.