Image forming device

Abstract

The present invention provides an image forming device. The image forming device includes: a rotating member that rotates; a primary transfer member that transfers a toner image to the rotating member; a secondary transfer member that transfers the toner image from the rotating member to a recording medium; a removing member that removes attached matter attached to the rotating member; a fixing device that generates heat to fix the toner image transferred to the recording medium by the secondary transfer member to the recording medium; a generating member that generates a flow of air from the fixing device side to the rotating member side; and an execution unit that executes a removal mode, heating the fixing device, operating the generating member, operating the rotating member, operating the primary transfer member to transfer a clean image, which is a toner image, to the rotating member, and removing the clean image from the rotating member by the removing member instead of transferring the clean image to the recording medium by the secondary transfer member.

Description

Technical Field

[0001] The present disclosure relates to an image forming apparatus. Background Art

[0002] The image forming device described in Japanese Patent Gazette No. 2015-225282 is composed of an image reading unit, an image processing unit, a paper size detection unit, a photosensitive drum, a photosensitive body drive unit, a charging device, an exposure device, a developing device, a transfer device, a cleaning device, a cleaning drive unit, an air supply device, a temperature and humidity detection device, a control unit, a static elimination device, a fixing device, a paper supply unit and a conveying unit. Summary of the Invention

[0003] An image forming apparatus includes a rotating member (transfer belt) that transfers a toner image from a photoreceptor to a recording medium as it rotates. During the transfer of the toner image to the recording medium, deposits such as discharge products adhere to the rotating member. After a certain period of time has passed since the image forming operation, deposits with increased adhesion to the rotating member may form. Furthermore, if these deposits absorb moisture, they may not be removed from the rotating member using only a scraper or other removal device.

[0004] An object of the present disclosure is to reduce the amount of deposits remaining on a rotating member, compared to a case where the deposits are removed from the rotating member simply by removing the member.

[0005] According to a first aspect of the present disclosure, an image forming apparatus is provided, comprising: a rotating member that rotates; a primary transfer member that transfers a toner image to the rotating member; a secondary transfer member that transfers the toner image of the rotating member to a recording medium; a removing member that is arranged on the downstream side of the secondary transfer member and the upstream side of the primary transfer member in the rotational direction of the rotating member, and removes attached matter attached to the rotating member; a fixing device that generates heat to fix the toner image transferred to the recording medium by the secondary transfer member to the recording medium; a generating member that generates a flow of air from the fixing device side to the rotating member side; and an execution unit that executes a removal mode, heats the fixing device, operates the generating member, operates the rotating member, operates the primary transfer member, transfers a cleaning image as a toner image to the rotating member, removes the cleaning image from the rotating member by the removing member, and does not transfer the cleaning image to the recording medium by the secondary transfer member.

[0006] According to the second aspect of the present disclosure, the execution unit executes the removal mode when a threshold time has elapsed after the image forming operation of forming an image on a recording medium is completed and the relative humidity in the apparatus body is equal to or higher than a threshold humidity.

[0007] According to the third scheme of the present disclosure, in the image forming device described in the first mode, when a threshold time has passed after the image forming action of forming an image in the recording medium and the relative humidity in the device body is above the threshold humidity and an image forming instruction of forming an image in the recording medium is received, the execution unit executes the removal mode before executing the image forming action.

[0008] According to a fourth aspect of the present disclosure, in the image forming apparatus according to the third aspect, the execution unit executes the removal mode when the recording medium designated to form a toner image in accordance with the image formation instruction is embossed paper having an embossed shape.

[0009] According to the 5th scheme of the present disclosure, in the image forming device described in any one of the 1st to 4th modes, the primary transfer member transfers the dot image as the cleaning image to the rotating member in the width direction of the rotating member with an image forming width for forming the colorant image and in the circumferential direction of the rotating member with a length greater than the circumferential length of the rotating member in such a manner that the image density of the cleaning image of the portion initially removed from the rotating member by the removing member becomes higher than the image density of the cleaning image of the portion finally removed from the rotating member by the removing member.

[0010] According to the sixth aspect of the present disclosure, in the image forming device described in the fifth aspect, the primary transfer member transfers the cleaning image to the rotating member in a manner in which the image density gradually decreases from the cleaning image of the portion initially removed from the rotating member by the removing member to the cleaning image of the portion finally removed.

[0011] (Effect)

[0012] According to the first aspect, compared with the case where the deposited matter is removed from the rotating member only by the removing member, the deposited matter remaining on the rotating member can be reduced.

[0013] According to the second aspect, the number of times the removal mode is executed can be reduced compared to a case where the removal mode is executed regardless of the elapsed time after the image forming operation ends and the relative humidity in the apparatus main body.

[0014] According to the third aspect, the number of times the deletion mode is executed can be reduced compared to a case where the deletion mode is executed even when no image formation instruction is received.

[0015] According to the fourth aspect, compared with executing the removal mode even when an image forming instruction designating embossed paper is not received, the number of executions of the removal mode can be reduced while maintaining the transfer quality of the toner image transferred from the rotating member to the embossed paper.

[0016] According to the fifth aspect, compared with a case where the image density of the cleaning image of the portion removed first from the rotating member is lower than the image density of the cleaning image of the portion removed last from the rotating member, it is possible to reduce the amount of attached matter remaining on the rotating member.

[0017] According to the sixth aspect, compared with a case where the cleaning image is composed of only the halftone dot image of the image density of the portion removed first from the rotating member and the halftone dot image of the image density of the portion removed last from the rotating member, it is possible to reduce the amount of attached matter remaining on the rotating member. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a configuration diagram showing a main part of the image forming apparatus according to the first embodiment of the present disclosure.

[0019] Figure 2 It is a structural diagram showing a removal member and the like included in the transfer section of the image forming apparatus according to the first embodiment of the present disclosure.

[0020] Figure 3 It is a perspective view showing an image forming section and a transfer section of the image forming apparatus according to the first embodiment of the present disclosure.

[0021] Figure 4 It is a perspective view showing a transfer section and the like of the image forming apparatus according to the first embodiment of the present disclosure.

[0022] Figure 5 It is a perspective view showing the belt unit and the fixing device of the image forming apparatus according to the first embodiment of the present disclosure.

[0023] Figure 6 (A) and (B) are process diagrams showing processes when the removal mode is executed in the image forming apparatus according to the first embodiment of the present disclosure.

[0024] Figure 7 (A) and (B) are process diagrams showing processes when the removal mode is executed in the image forming apparatus according to the first embodiment of the present disclosure.

[0025] Figure 8 This is a block diagram illustrating a control system of a control unit included in the image forming apparatus according to the first embodiment of the present disclosure.

[0026] Figure 9This is a flowchart showing a flow when the removal mode is executed in the image forming apparatus according to the first embodiment of the present disclosure.

[0027] Figure 10 It is a cross-sectional view showing the developing device of the image forming apparatus according to the first embodiment of the present disclosure.

[0028] Figure 11 This is a diagram schematically illustrating the configuration of an image forming apparatus according to a first embodiment of the present disclosure.

[0029] Figure 12 This is a block diagram illustrating a control system of a control unit included in an image forming apparatus according to a second embodiment of the present disclosure.

[0030] Figure 13 This is a flowchart showing a flow when the removal mode is executed in the image forming apparatus according to the second embodiment of the present disclosure. DETAILED DESCRIPTION

[0031] <First embodiment>

[0032] according to Figures 1 to 11 An example of an image forming apparatus according to the first embodiment of the present disclosure will be described. Arrow H in each figure indicates the vertical direction and the apparatus up-down direction, arrow W indicates the horizontal direction and the apparatus width direction, and arrow D indicates the horizontal direction and the apparatus depth direction.

[0033] (Overall Structure of Image Forming Apparatus)

[0034] like Figure 11 As shown, the image forming apparatus 10 includes an image forming unit 12 that forms a toner image using an electrophotographic method; a storage unit 18 that stores a recording medium P; a control unit 28 that controls each unit; and an exhaust unit 24. Furthermore, the image forming apparatus 10 includes a conveying unit 14 that conveys the recording medium P stored in the storage unit 18 along a conveying path 16, conveys the recording medium P conveyed along the conveying path 16 along a reversing path 26, reverses the front and back surfaces of the recording medium P, and then conveys the recording medium P toward the image forming unit 12 again.

[0035] In this configuration, in the image forming apparatus 10, a toner image formed by the image forming section 12 is formed on the surface of a recording medium P conveyed along the conveyance path 16. The recording medium P with the toner image formed thereon is then discharged to the outside of the apparatus main body 10a.

[0036] On the other hand, when an image is formed on the back side of the recording medium P, the recording medium P with the image formed on the surface is transported along the reversing path 26, and an image is formed on the back side of the recording medium P again by the image forming unit 12 and discharged to the outside of the device body 10a.

[0037] [Image forming unit 12]

[0038] like Figure 11 As shown, the image forming section 12 includes a plurality of toner image forming sections 30 that form toner images of respective colors, and a transfer section 32 that transfers the toner images formed by the toner image forming sections 30 to a recording medium P. Furthermore, the image forming section 12 includes a fixing device 34 that fixes the toner images transferred to the recording medium P by the transfer section 32 to the recording medium P.

[0039] -Toner Image Forming Section 30-

[0040] like Figure 1 As shown, a plurality of toner image forming units 30 are provided to form toner images for each color. In this embodiment, toner image forming units 30 for a total of four colors are provided: yellow (Y), magenta (M), cyan (C), and black (K). In the following description, when it is not necessary to distinguish between yellow (Y), magenta (M), cyan (C), and black (K), the numbers Y, M, C, and K are omitted.

[0041] The toner image forming unit 30 for each color is basically the same in structure except for the toner used, and includes a rotating cylindrical image holder 40 and a charger 42 for charging the image holder 40. The toner image forming unit 30 also includes an exposure device 44 for irradiating the charged image holder 40 with exposure light to form an electrostatic latent image, and a developing device 46 for developing the electrostatic latent image into a toner image using a developer G containing toner. Figure 10 As shown, the developing device 46 includes: a developing roller 46 a facing the image holding member 40 ; a supply auger 46 b for supplying the developer G to the developing roller 46 a ; and a stirring auger 46 c for stirring the developer G.

[0042] In this configuration, in the toner image forming sections 30 for the respective colors, images of the respective colors are formed using the toners of the respective colors.

[0043] And, as Figure 1As shown, the image holders 40 of each color are in contact with a rotating transfer belt 50 (described in detail later). Furthermore, the toner image forming units 30 for yellow (Y), magenta (M), cyan (C), and black (K) are arranged in order horizontally from the upstream side in the rotation direction of the transfer belt 50 (see arrow in the figure).

[0044] -Transfer unit 32-

[0045] like Figure 1 As shown, the transfer section 32 includes a plurality of rollers 58, a take-up roller 56, a transfer belt 50 wound around the plurality of rollers 58 and the take-up roller 56 and rotating in the direction of the arrow in the figure, a primary transfer roller 52, a removing member 36, and a secondary transfer roller 54. Furthermore, a secondary transfer section NT is formed between the secondary transfer roller 54 and the transfer belt 50 for transferring the toner image to the recording medium P. The structure of the transfer section 32 will be described in detail later.

[0046] -Fixing device 34-

[0047] like Figure 1 As shown, the fixing device 34 is arranged on the downstream side of the secondary transfer portion NT in the conveyance direction of the recording medium P. The fixing device 34 will be described in detail later.

[0048] [Accommodation portion 18]

[0049] like Figure 11 As shown, the storage section 18 includes a storage member 20 capable of storing the recording medium P, and a delivery roller 22 that delivers the uppermost recording medium P loaded in the storage member 20 to the transport path 16 .

[0050] [Transportation Department 14]

[0051] like Figure 11 As shown, the conveying section 14 includes a plurality of conveying rollers (reference numerals omitted) that convey the recording medium P fed from the storage section 18 along the conveying path 16, and a belt unit 60 that conveys the recording medium P to which the toner image has been transferred and delivers it to the fixing device 34. The belt unit 60 will be described in detail later.

[0052] The transport section 14 further includes a plurality of transport rollers (reference numerals omitted) that transport the recording medium P along a reversing path 26. When an image is formed on the back side of the recording medium P, the recording medium P that has passed through the fixing device 34 is fed into the reversing path 26. In the reversing path 26, the front and back sides of the recording medium P are reversed by reversing the transport direction of the recording medium P (switching the recording medium P back).

[0053] In this configuration, with a toner image formed on the surface of the recording medium P, the conveying section 14 conveys the recording medium P fed from the storage section 18 along the conveying path 16. Then, in the secondary transfer section NT, the toner image is transferred to the surface of the recording medium, and the fixing device 34 fixes the toner image to the recording medium P.

[0054] When a toner image is also formed on the back side of the recording medium P, the conveying section 14 conveys the recording medium P that has passed through the fixing device 34 along the reversing path 26, thereby reversing the front and back sides of the recording medium P. The conveying section 14 then merges the recording medium P, with its front and back sides reversed, into the conveying path 16 and conveys the recording medium P along the conveying path 16. Then, in the secondary transfer section NT, the toner image is transferred to the back side of the recording medium, and the fixing device 34 fixes the toner image to the recording medium P.

[0055] (Exhaust unit 24)

[0056] like Figure 11 As shown, the exhaust unit 24 is attached to the device body 10a so as to exhaust the air inside the device body 10a to the outside of the device body 10a. The exhaust unit 24 will be described in detail later.

[0057] (Control Unit 28)

[0058] like Figure 8 As shown in FIG, the control unit 28 controls each part. In addition, the control of each part by the control unit 28 will be described together with the operation to be described later.

[0059] (The role of the overall structure)

[0060] In the image forming apparatus 10 , an image is formed as follows.

[0061] first, Figure 1 The chargers 42 for each color shown negatively charge the surfaces of the image holders 40 of each color to a predetermined potential. Next, the exposure device 44 irradiates the charged surfaces of the image holders 40 of each color with exposure light, forming an electrostatic latent image. This forms an electrostatic latent image on the surfaces of the image holders 40 of each color. Furthermore, the developing devices 46 for each color develop the electrostatic latent image to visualize it as a toner image. The toner images formed on the surfaces of the image holders 40 of each color are then sequentially transferred to the transfer belt 50 via the primary transfer roller 52.

[0062] Therefore, the delivery roller 22 is used to Figure 11The recording medium P fed from the container 20 to the transport path 16 is fed to the secondary transfer section NT where the transfer belt 50 contacts the secondary transfer roller 54. In the secondary transfer section NT, the recording medium P is transported between the transfer belt 50 and the secondary transfer roller 54, whereby the toner image on the transfer belt 50 is transferred to the surface of the recording medium P.

[0063] Then, the toner image transferred to the surface of the recording medium P is fixed to the recording medium P by the fixing device 34. Then, the recording medium P to which the toner image is fixed is discharged to the outside of the apparatus main body 10a.

[0064] On the other hand, if a toner image is also formed on the back side of the recording medium P, the recording medium P with the toner image formed on its front side is conveyed along the reversing path 26, thereby being reversed and conveyed again to the secondary transfer unit NT. Then, through the same process as described above, the formed toner image is transferred to the back side of the recording medium P. The toner image transferred to the back side of the recording medium P is fixed to the recording medium P by the fixing device 34. The recording medium P with the fixed toner image is then discharged outside the apparatus main body 10a.

[0065] (Main structure)

[0066] Next, the transfer section 32 , the fixing device 34 , the belt unit 60 of the conveying section 14 , the exhaust unit 24 , the control section 28 , and the like will be described.

[0067] [Transfer section 32]

[0068] like Figure 1 、 Figure 4 As shown, the transfer unit 32 includes a plurality of rollers 58, a take-up roller 56, and a transfer belt 50 that is wound around the plurality of rollers 58 and the take-up roller 56 and rotates in the direction of arrow G in the figure. When wound around the plurality of rollers 58 and the take-up roller 56, the transfer belt 50 has a triangular shape with its apex facing downward when viewed from the depth direction of the device. The transfer belt 50 is an example of a rotating member.

[0069] The transfer unit 32 includes a primary transfer roller 52 that transfers the toner images formed on the image holder 40 of each color to the transfer belt 50 using a transfer current. The transfer unit 32 also includes a secondary transfer roller 54 that transfers the toner images on the transfer belt 50 to the recording medium P using a transfer current, and a removal member 36 that removes deposits such as discharge products from the transfer belt 50. The primary transfer roller 52 is an example of a primary transfer member, and the secondary transfer roller 54 is an example of a secondary transfer member.

[0070] The top portion of the transfer belt 50 is wound around a winding roller 56, while the portion of the transfer belt 50 on one side (right side in the figure) in the width direction of the device is wound around roller 58a, which constitutes roller 58. Then, by rotating one of the multiple rollers 58, the transfer belt 50 rotates in the direction of arrow G (counterclockwise) in the figure. Furthermore, the image holders 40 of each color contact the portion of the transfer belt 50 with its circumferential surface facing upward. The image holders 40 (toner image forming unit 30) for yellow (Y), magenta (M), cyan (C), and black (K) are arranged in order from the upstream side in the direction of rotation of the transfer belt 50.

[0071] The primary transfer rollers 52 are disposed on the opposite side of the transfer belt 50 from the image holders 40 of the respective colors. Furthermore, the secondary transfer roller 54 is disposed on the opposite side of the transfer belt 50 from the take-up roller 56. A secondary transfer portion NT for transferring a toner image onto a recording medium P is formed between the secondary transfer roller 54 and the transfer belt 50.

[0072] The removal member 36 is arranged on the downstream side of the secondary transfer member and the upstream side of the primary transfer roller 52 in the rotation direction of the transfer belt 50 (hereinafter referred to as the "belt rotation direction") and on the opposite side of the roller 52a across the transfer belt 50. Figure 2 As shown, the removing member 36 includes a scraper 36 a whose distal end contacts the peripheral surface of the transfer belt 50 to scrape off the attached matter attached to the transfer belt 50 , and a recovery box 36 b that recovers the attached matter scraped off by the scraper 36 a .

[0073] In this configuration, the removing member 36 removes debris attached to the transfer belt 50. In other words, the removing member 36 suppresses local changes in the electrical properties of the transfer belt 50. Specifically, the removing member 36 functions as a performance maintaining unit that maintains the electrical properties of the transfer belt 50.

[0074] [Fixing device 34]

[0075] like Figure 1 As shown, the fixing device 34 is arranged downstream of the secondary transfer portion NT and below the transfer belt 50 in the conveyance direction of the recording medium P (hereinafter referred to as the "medium conveyance direction"). Thus, the fixing device 34 is arranged in the area where the transfer belt 50 is arranged in the device width direction.

[0076] The fixing device 34 includes a heating roller 34 a having a heat source therein and being rotated by a driving unit, and a pressure roller 34 b disposed opposite the heating roller 34 a and pressing the recording medium P to which the toner image has been transferred against the heating roller 34 a .

[0077] In this configuration, when fixing the toner image transferred to the recording medium P to the recording medium P, the peripheral surface of the heating roller 34a is raised to, for example, approximately 180°C. The rotating heating roller 34a and the pressure roller 34b, which rotates in a driven manner by the heating roller 34a, then sandwich the recording medium P and convey it, thereby fixing the toner image to the recording medium P.

[0078] [Belt unit 60]

[0079] like Figure 1 As shown, the belt unit 60 is arranged downstream of the secondary transfer portion NT and upstream of the fixing device 34 in the medium conveyance direction.

[0080] like Figure 1 、 Figure 5 As shown, the belt unit 60 includes an endless conveyor belt 62 , a driving roller 64 a and a driven roller 64 b around which the conveyor belt 62 is wound, and an air intake section 66 that sucks air from above the conveyor belt 62 .

[0081] Multiple conveyor belts 62 are arranged side by side in the depth direction of the apparatus, and multiple through-holes 62a are formed in the conveyor belts 62. Furthermore, an air suction fan 66a is disposed within the air suction unit 66. As the air suction fan 66a operates, the air suction unit 66 draws in air from above the conveyor belts 62, causing the recording medium P to be attracted to the conveyor belts 62.

[0082] In this structure, the rotationally driven driving roller 64a transmits the rotational force to the conveyor belt 62, causing the conveyor belt 62 to rotate. Furthermore, the air suction unit 66 absorbs the air above the conveyor belt 62, and the belt unit 60 conveys the recording medium P while adsorbing it on the conveyor belt 62. If the suction fan 66a is operated without conveying the recording medium P, as shown in FIG. Figure 1 As shown by arrow A, the air on the heating roller 34a side flows toward the belt unit 60. In other words, the air on the heating roller 34a side flows toward the transfer belt 50 side by the operating suction fan 66a.

[0083] [Exhaust unit 24]

[0084] like Figure 1 As shown, when viewed from the depth direction of the device, the exhaust unit 24 is arranged on the side opposite to the fixing device 34 across the transfer belt 50, as shown in FIG. Figure 3 As shown, it is mounted on the back plate 70 of the apparatus body 10a. The exhaust unit 24 is an example of a generating member.

[0085] The exhaust unit 24 includes an exhaust fan 72 and an exhaust duct 74 . The base end of the exhaust duct 74 is connected to the exhaust fan 72 , and the distal end of the exhaust duct 74 is open toward the peripheral surface of the transfer belt 50 .

[0086] In this configuration, by operating the exhaust fan 72 , the exhaust unit 24 sucks air from the peripheral surface of the transfer belt 50 , passes the air through a filter (not shown), and then exhausts the air to the outside of the apparatus body 10 a .

[0087] Furthermore, if the exhaust fan 72 is operated, Figure 1 As shown by arrow B, air flows from the heating roller 34a side of the fixing device 34 toward the transfer belt 50 side. This causes the temperature of the transfer belt 50 to rise. In other words, the heating roller 34a and the exhaust unit 24 function as a temperature-raising unit that raises the temperature of the transfer belt 50. The direction of the air flow can be confirmed by observing the direction of the flow of a substance such as white mist generated by placing dry ice inside the device main body 10a.

[0088] 〔other〕

[0089] like Figure 8 As shown, the image forming apparatus 10 includes a measuring unit 80 that measures the time elapsed after the image forming operation of forming an image on the recording medium P is completed, and a hygrometer 82 that detects the relative humidity in the apparatus main body 10 a.

[0090] Here, the "relative humidity within the device body" refers to the relative humidity of the area within the device body 10a where the transfer belt 50 is located. Specifically, it refers to the relative humidity of any location within the area between the peripheral surface of the transfer belt 50 and a position 200 mm away from the peripheral surface of the transfer belt 50, as viewed from the depth of the device. In this embodiment, the hygrometer 82 is, as an example, located below the removal portion 36.

[0091] [Control Unit 28]

[0092] like Figure 8 As shown, the control unit 28 receives information from the measuring unit 80 and the hygrometer 82 and controls the operation of the exhaust fan 72, the fixing device 34, the toner image forming unit 30, and the transfer unit 32. The control of each unit by the control unit 28 will be described together with its functions described below. The control unit 28 is an example of an execution unit.

[0093] (effect)

[0094] Next, the functions of the main structure are explained. Figure 9 The flowchart shown here describes a process in which the control unit 28 controls each unit to execute a removal mode for removing adhering matter adhering to the transfer belt 50 .

[0095] When the image forming operation for forming an image on the recording medium P is completed, the control unit 28 stops the operation of the fixing device 34, the conveying unit 14, the toner image forming unit 30, and the transfer unit 32. Furthermore, when the image forming operation is completed, the measuring unit 80 measures the elapsed time after the image forming operation is completed.

[0096] Then, the control unit 28 Figure 9 In step S100, a determination is made as to whether the elapsed time measured by the measuring unit 80 has exceeded a threshold time. If the elapsed time has exceeded the threshold time, the process proceeds to step S200. If the elapsed time has not reached the threshold time, the control unit 28 again determines whether the elapsed time has exceeded the threshold time in step S100. In this embodiment, the threshold time is between 4 hours and 72 hours, preferably between 5 hours and 10 hours, and particularly preferably between 6 hours and 8 hours. The determination as to whether the elapsed time has reached the threshold time is based on the fact that if the elapsed time has reached the threshold time, the adhesion of the attached objects to the transfer belt 50 will be stronger than if the elapsed time has not reached the threshold time.

[0097] Furthermore, when the main power of the image forming apparatus 10 is turned off, after the main power is turned on, in step S100 , the control unit 28 determines whether the elapsed time measured by the measuring unit 80 has exceeded the threshold time.

[0098] Next, in step S200, the control unit 28 determines whether the relative humidity measured by the hygrometer 82 at the time of the transition to step S200 has reached the threshold humidity. If the relative humidity has reached the threshold humidity, the process proceeds to step S300. If the relative humidity has not reached the threshold humidity, the control unit 28 again determines in step S100 whether the elapsed time has exceeded the threshold time. The determination of whether the relative humidity has reached the threshold humidity is based on the fact that if the relative humidity has reached the threshold humidity, the adhesion of objects attached to the transfer belt 50 is stronger than if the relative humidity has not reached the threshold humidity.

[0099] Furthermore, after the main power is turned on, when the control unit 28 determines the elapsed time in step S100 , it determines the relative humidity when the process shifts from determination step 100 to step S200 .

[0100] Next, in step S300, the control unit 28 makes Figure 1 The exhaust fan 72 and the fixing device 34 are shown in operation. The fixing device 34 is operated so that the temperature of the peripheral surface of the heating roller 34a is the same as that during the image forming operation.

[0101] As the exhaust fan 72 and the fixing device 34 are operated in this manner, the air heated by the heating roller 34 a flows toward the transfer belt 50 (see arrow B in the figure), thereby heating the transfer belt 50 .

[0102] Next, in step S400, the control unit 28 makes Figure 1 The black toner image forming section 30K and the transfer section 32 are shown to be in operation.

[0103] The control unit 28 causes the toner image forming unit 30K to form a cleaning image as an example of a toner image, rotates the transfer belt 50, and transfers the cleaning image to the transfer belt 50 via the primary transfer roller 52. Furthermore, the control unit 28 causes a transfer current to flow to the secondary transfer roller 54 so as to generate an electric field opposite to that when the toner image is transferred to the recording medium P.

[0104] Specifically, the toner image forming unit 30K forms a halftone dot image as a cleaning image. Furthermore, the primary transfer roller 52 transfers the halftone dot image as a cleaning image to the transfer belt 50 over a width corresponding to the image forming width of the toner image and over a length greater than the circumferential length of the transfer belt 50. In other words, the primary transfer roller 52 transfers the halftone dot image as a cleaning image to the transfer belt 50 such that the portion of the transfer belt 50 to which the cleaning image is first transferred overlaps the portion of the transfer belt 50 to which the cleaning image is last transferred. "Image forming width" refers to the maximum width of an image that can be formed. Furthermore, a "halftone dot image" refers to an image composed of uniformly distributed dots.

[0105] Here, the primary transfer roller 52 transfers the clean image to the transfer belt 50 in a manner such that the image density gradually decreases from the portion of the clean image first transferred to the transfer belt 50 to the portion of the clean image last transferred to the transfer belt 50. In other words, the primary transfer roller 52 transfers the clean image to the transfer belt 50 in a manner such that the image density gradually decreases from the portion of the clean image first scraped and removed from the transfer belt 50 by the scraper 36a to the portion of the clean image last scraped and removed. In this embodiment, as an example, the image density changes from 100% to 60%. The image density of the halftone dot image, which is the clean image, can be measured using a spectrodensitometer (X-Rite 939 manufactured by X-Rite). Alternatively, the mass of the toner per unit area of the transfer belt 50 can be measured and the image density derived from this mass. Furthermore, in this embodiment, a halftone dot image with an image density of 100% is a three-dimensional image.

[0106] In this way, by operating the toner image forming section 30K and the transfer section 32, as shown in FIG. Figure 6As shown in (A) and (B) of FIG. 8 , the cleaning image (G01 shown in the figure) transferred to the heated transfer belt 50 is conveyed by the rotating transfer belt 50.

[0107] Then, if Figure 7 As shown in (A) and (B) of FIG5 , in step S500 , when the cleaning image G01 transferred to the transfer belt 50 is removed by the removal portion 38 , the rotation of the rotating transfer belt 50 is stopped.

[0108] Specifically, the clean image G01 conveyed by the rotating transfer belt 50 passes through the secondary transfer section NT and reaches the removal section 38. The scraper 36a of the removal section 38 scrapes the clean image G01 conveyed by the transfer belt 50 from the transfer belt 50, and the recovery box 36b recovers the toner constituting the clean image G01 scraped from the transfer belt 50.

[0109] Here, the cleaning image G01 is scraped off from the transfer belt 50 by the scraper 36a. Figure 2 As shown, a toner reservoir T01 is generated at a portion where the distal end of the scraper 36 a contacts the transfer belt 50 .

[0110] The toner constituting the toner storage portion T01 becomes an abrasive, and the adhering matter adhering to the peripheral surface of the transfer belt 50 is scraped off and removed from the transfer belt 50 .

[0111] The toner constituting the toner reservoir T01 drops over time and is collected in the collection box 36b. However, new toner is replenished to the toner reservoir T01 by the toner of the clean image G01 scraped from the transfer belt 50 by the scraper 36a. This maintains the toner reservoir T01 as an abrasive.

[0112] As previously described, the image density gradually decreases from the clean image of the portion scraped from the transfer belt 50 by the scraper 36a to the clean image of the portion scraped from the transfer belt 50 last. In other words, the amount of toner scraped from the transfer belt 50 by the scraper 36a gradually decreases from the clean image of the portion scraped from the transfer belt 50 first to the clean image of the portion scraped from the transfer belt 50 last. Therefore, compared to a case where the amount of toner scraped from the transfer belt 50 by the scraper 36a first and the amount of toner removed by the final scraping are the same, the toner reservoir T01 is formed more quickly.

[0113] Then, when the scraper 36 a scrapes off all of the cleaning image G01 transferred to the transfer belt 50 , the control unit 28 stops the operation of each unit and ends a series of operations.

[0114] (Summarize)

[0115] As described above, in the image forming apparatus 10, when the control unit 28 is in the removal mode for removing deposits from the transfer belt 50, it operates the exhaust fan 72 and the fixing device 34, causing air heated by the heating roller 34a to flow toward the transfer belt 50. This heats the transfer belt 50. Heating the transfer belt 50 weakens the adhesion of deposits to the transfer belt 50 compared to a situation where the transfer belt 50 is not heated. Consequently, less deposits remain on the transfer belt 50 than when only the removal member 36 is used to remove deposits from the transfer belt 50.

[0116] Furthermore, in the image forming apparatus 10, compared to removing deposits from the transfer belt 50 solely by the removal member 36, the amount of deposits remaining on the transfer belt 50 is reduced, thereby improving the transfer performance of the toner image from the transfer belt 50 to the recording medium P. This is particularly true when embossed paper, such as embossed paper, is used as the recording medium P. The transfer performance of the toner image from the transfer belt 50 to the recording medium P is improved. Here, "embossed paper" refers to paper with a convex-concave pattern. For example, the height difference of the convex-concave portion is between 0.05 mm and 1 mm. Furthermore, in the image forming apparatus 10, the control unit 28 executes the removal mode when a threshold time has passed since the image forming operation ended and the relative humidity within the apparatus main body 10a is above the threshold humidity. By executing the removal mode when the adhesion of the attached matter to the transfer belt 50 becomes stronger, the number of times the removal mode is executed can be reduced, as compared to a case where the removal mode is executed regardless of the time elapsed after the completion of the image forming operation and the relative humidity within the apparatus main body 10a. Furthermore, "completion of the image forming operation" refers to the time when the toner image is fixed to the last sheet member P.

[0117] Furthermore, in the image forming apparatus 10, the toner reservoir T01 of a predetermined size is formed more quickly than when the amount of toner initially scraped from the transfer belt 50 by the scraper 36a is less than the amount of toner ultimately scraped. In other words, abrasive is generated more quickly than when the amount of toner initially scraped from the transfer belt 50 by the scraper 36a is the same as the amount of toner ultimately scraped. This reduces the amount of attached matter remaining on the transfer belt 50.

[0118] Furthermore, in the image forming apparatus 10, the image density gradually decreases from the clean image of the portion first removed from the transfer belt 50 by the removing member 36 to the clean image of the portion removed last. Therefore, compared to a case where the clean image is composed solely of a halftone dot image having the image density of the portion first removed from the transfer belt 50 and a halftone dot image having the image density of the portion finally removed from the rotating member, the toner reservoir T01 having a predetermined size is maintained, thereby reducing the amount of attached matter remaining on the transfer belt 50.

[0119] <Second embodiment>

[0120] Then, according to Figure 12 、 Figure 13 An example of an image forming apparatus according to a second embodiment of the present disclosure will be described. The second embodiment will be described mainly focusing on differences from the first embodiment.

[0121] (structure)

[0122] like Figure 12 As shown, the image forming apparatus 210 according to the second embodiment has a storage unit 20 (see FIG. Figure 11 ) is a storage unit 84 for storing the paper type, etc. of the recording medium P.

[0123] The control unit 228 of the image forming apparatus 210 receives information from the storage unit 84, the measuring unit 80, and the hygrometer 82, and controls the operation of the exhaust fan 72, the fixing device 34, the toner image forming unit 30, and the transfer unit 32. The control of each component by the control unit 228 will be described below together with its functions. The control unit 228 is an example of an execution unit.

[0124] (effect)

[0125] Next, use Figure 13 The flowchart shown here describes a process in which the control unit 228 controls each unit to execute a removal mode for removing adhering matter adhering to the transfer belt 50 .

[0126] When the image forming operation is completed, the measuring unit 80 measures the time elapsed after the image forming operation is completed. Figure 13 In step S1100 shown, it is determined whether the elapsed time measured by the measuring unit 80 has reached the threshold time. If the elapsed time has reached the threshold time, the process proceeds to step S1200. If the elapsed time has not reached the threshold time, the control unit 228 again determines in step S1100 whether the elapsed time has exceeded the threshold time.

[0127] Next, in step S1200, the control unit 228 determines whether the relative humidity measured by the hygrometer 82 has reached the threshold humidity when the process moves to step S1200. If the relative humidity has reached the threshold humidity, the process moves to step S1300. If the relative humidity has not reached the threshold humidity, the control unit 228 again determines in step S1100 whether the elapsed time has exceeded the threshold time.

[0128] Next, in step S1300, the control unit 228 determines whether an image formation instruction (print job) has been received to form a toner image on embossed recording medium P. Specifically, the control unit 228 uses the information stored in the storage unit 84 to determine whether the recording medium P specified by the image formation instruction is embossed paper.

[0129] When an image forming instruction to form a colorant image in the recording medium P as embossed paper is received, the process proceeds to step S1400. When an image forming instruction to form a colorant image in the recording medium P as embossed paper is not received, the control unit 228 again determines whether an image forming instruction has been received in step S1300.

[0130] In step S1400, the control unit 228 makes Figure 1 The exhaust fan 72 and the fixing device 34 are shown in operation. The fixing device 34 is operated so that the temperature of the peripheral surface of the heating roller 34a is the same as that during the image forming operation.

[0131] In step S1500, the control unit 228 makes Figure 1 The black toner image forming section 30K and the transfer section 32 are shown to be in operation.

[0132] The control unit 228 causes the toner image forming unit 30K to form a cleaning image, which is an example of a toner image, and rotates the transfer belt 50 to transfer the cleaning image formed by the primary transfer roller 52 to the transfer belt 50. Furthermore, the control unit 228 causes a transfer current to flow to the secondary transfer roller 54 so as to generate an electric field opposite to that when the toner image is transferred to the recording medium P.

[0133] Then, if Figure 7 As shown in (A) and (B) of FIG. 1 , when the cleaning image G01 transferred to the transfer belt 50 is removed by the removal unit 38 in step S1600, the rotation of the transfer belt 50 is stopped. Then, the control unit 28 stops the operation of each unit, completing a series of operations.

[0134] (Summarize)

[0135] As described above, in the image forming apparatus 210, the control unit 228 executes the removal mode before performing the image forming operation when receiving an image forming instruction to form a toner image on the recording medium P, which is embossed paper. Therefore, compared to a case where the removal mode is executed even when no image forming instruction to form a toner image on the recording medium P, which is embossed paper, has been received, the number of times the removal mode is executed is reduced while maintaining the transfer performance of the toner image transferred from the transfer belt 50 to the embossed paper.

[0136] In addition, although the present disclosure describes specific embodiments in detail, the present disclosure is not limited to the embodiments described, and it is clear to those skilled in the art that various other embodiments can be adopted within the scope of the present disclosure. For example, in the above-described embodiments, the removal mode is executed when a specified condition is met, but the removal mode can also be executed by, for example, providing an indicator switch indicating the execution of the removal mode and turning on the indicator switch by the user.

[0137] Furthermore, in the above embodiment, the relative humidity within the device body 10a being equal to or higher than the threshold humidity is one of the conditions for executing the removal mode. However, the removal mode may be executed regardless of the relative humidity within the device body 10a. However, in this case, the effect obtained by setting the relative humidity as one of the conditions for executing the removal mode is not achieved.

[0138] Furthermore, in the above embodiment, the removing member 36 including the scraper 36 a is described as an example of a removing member for removing adhering matter from the transfer belt 50 . However, a removing member including a removing brush or the like may also be used.

[0139] Furthermore, in the above embodiment, the tandem image forming apparatus 10 is described. However, a rotary image forming apparatus may be used as long as it has a transfer belt or a transfer drum.

[0140] Furthermore, in the second embodiment described above, the removal mode is executed when an image formation instruction is received to form a toner image on a recording medium P that is embossed paper. However, the removal mode may also be executed when an image formation instruction is received to form a toner image on the recording medium P regardless of the paper type. This reduces the number of executions of the removal mode while maintaining the transfer quality of the toner image transferred from the transfer belt 50 to the recording medium P, compared to executing the removal mode even when no image formation instruction is received. However, in this case, the effect of the recording medium P being embossed paper, which is designated for toner image formation, is not achieved.

[0141] Furthermore, although not specifically described in the above embodiment, the suction fan 66a of the belt unit 60 may be operated in the removal mode. By operating the suction fan 66a, the heat of the heating roller 34a is suppressed from flowing in the direction of retreating from the transfer belt 50 (see FIG. Figure 1 arrow A).

[0142] Furthermore, in the above embodiment, the cleaning image is formed by the black toner image forming portion 30K, but the cleaning image may be formed by toner image forming portions 30 of other colors, or a plurality of toner image forming portions may be used.

[0143] Furthermore, in the above-described embodiment, the primary transfer roller 52 transfers the cleaning image to the transfer belt 50 such that the image density gradually decreases from the portion of the cleaning image transferred first to the transfer belt 50 to the portion of the cleaning image transferred last to the transfer belt 50. However, the cleaning image may be any other image as long as it is continuous in the rotational direction of the transfer belt 50.

[0144] Furthermore, in the above-described embodiment, the primary transfer roller 52 transfers the clean image to the transfer belt 50 so that the image density gradually decreases from the portion of the clean image transferred first to the transfer belt 50 to the portion of the clean image transferred last to the transfer belt 50. However, the primary transfer roller 52 may transfer the clean image to the transfer belt 50 so that the image density gradually decreases.

[0145] Furthermore, in the above embodiment, the halftone dot image as the cleaning image is formed by the toner image forming section 30K. However, the halftone dot image as the cleaning image may be formed by the toner image forming section 30 of another color.

[0146] Furthermore, in the second embodiment described above, the rotation of the transfer belt 50 is stopped in step S1600 . However, the print job received in step S1300 may be executed without stopping the rotation of the transfer belt 50 .

Claims

1. An image forming apparatus comprising: a rotating part that rotates; a primary transfer member that transfers the toner image to the rotating member; a secondary transfer member that transfers the toner image of the rotating member to a recording medium; a removing member disposed downstream of the secondary transfer member and upstream of the primary transfer member in the rotation direction of the rotating member, for removing attached matter attached to the rotating member; a fixing device that generates heat to fix the toner image transferred to the recording medium by the secondary transfer member to the recording medium; a generating member that generates a flow of air from the fixing device side to the rotating member side; as well as an execution section that executes a removal mode, generates heat in the fixing device, operates the generating member, operates the rotating member, operates the primary transfer member, transfers a cleaning image as a toner image to the rotating member, removes the cleaning image from the rotating member by the removing member, and does not transfer the cleaning image to a recording medium by the secondary transfer member, The execution unit executes the removal mode when a threshold time has elapsed after an image forming operation of forming an image on a recording medium is completed and the relative humidity in the apparatus body is equal to or higher than a threshold humidity.

2. The image forming apparatus according to claim 1, wherein When a threshold time has passed after an image forming operation to form an image on a recording medium is completed, the relative humidity in the apparatus body is above a threshold humidity, and an image forming instruction to form an image on a recording medium is received, the execution unit executes the removal mode before executing the image forming operation.

3. The image forming apparatus according to claim 2, wherein: The execution unit executes the removal mode when the recording medium designated to form a toner image in accordance with the image formation instruction is embossed paper having an embossed shape.

4. The image forming apparatus according to any one of claims 1 to 3, wherein: The primary transfer member transfers the halftone dot image, which is the cleaning image, to the rotating member over an image forming width in the width direction of the rotating member in which the toner image is formed and over a length in the circumferential direction of the rotating member that is greater than the circumferential length of the rotating member in such a manner that the image density of the cleaning image in the portion that is first removed from the rotating member by the removing member becomes higher than the image density of the cleaning image in the portion that is last removed from the rotating member by the removing member.

5. The image forming apparatus according to claim 4, wherein The primary transfer member transfers the cleaning image to the rotating member in such a manner that the image density gradually decreases from the portion of the cleaning image first removed from the rotating member by the removing member to the portion of the cleaning image last removed.

Images