Image forming apparatus

Abstract

To prevent cleaning failures even with low toner consumption, suppress uneven friction in new intermediate transfer media, and prevent the cleaning blade from curling. [Solution] The output image pattern has toner image groups Tn1 and Tn2 in which toner image parts Ta and non-toner image parts Tb are arranged alternately in the width direction, with the toner image parts Ta of toner image group Tn1 and the non-toner image parts Tb of toner image group Tn2 being adjacent to each other, and the non-toner image parts Tb of toner image group Tn1 and the toner image parts Ta of toner image group Tn2 being adjacent to each other.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus and an image forming system that form an image on a recording material.

Background Art

[0002] In an image forming apparatus using an electrophotographic method, an intermediate transfer method that performs primary transfer and secondary transfer is widely used. In an image forming apparatus using the intermediate transfer method, there is a blade cleaning method for removing toner (hereinafter referred to as transfer residual toner) remaining on the intermediate transfer body after secondary transfer in preparation for the next image formation. In this method, the transfer residual toner is scraped off by a cleaning blade, and the scraped transfer residual toner is collected in a cleaning container. In the blade cleaning method, if the intermediate transfer body continues to rotate in a state where a lubricant such as toner is not supplied to the position where the intermediate transfer body and the cleaning blade contact, the tip of the cleaning blade may be卷入 in the conveyance direction of the intermediate transfer body. This is because a large frictional force is generated in the nip portion between the cleaning blade and the intermediate transfer body. As a result, there is a risk of occurrence of cleaning defects and the like caused by the transfer residual toner passing through the cleaning blade. For example, in Patent Document 1, a configuration is proposed in which toner as a lubricant is periodically supplied to the cleaning blade portion in order not to generate an excessive frictional force between the cleaning blade and the intermediate transfer body. Thereby, the lubricity between the cleaning blade and the intermediate transfer body is maintained, and the cleaning property of the intermediate transfer body is stabilized.

[0003] Note: The Chinese character "卷入" in the original text is not a standard expression. I translated it as "卷入" for the purpose of literal translation. It might need to be adjusted according to the actual context to a more appropriate expression like "entangled" or "drawn in".Some intermediate transfer bodies use coarse particles with a particle size distribution (such as emulsion-polymerized PTFE resin particles) on their surface, resulting in uneven surface roughness due to the particle size distribution. Uneven friction occurs at the nip between the surface of a new intermediate transfer body and the cleaning blade, which can cause the cleaning blade to curl in areas of high friction. When curling occurs, toner and external additives cannot be collected at the nip between the intermediate transfer body and the cleaning blade, potentially leading to poor cleaning as they slip through. To prevent the cleaning blade from curling, one method is to apply toner as a lubricant to the entire surface of a new intermediate transfer body to reduce uneven friction. In addition, to improve the cleaning performance of the cleaning blade, it is common practice to form a deposit layer for cleaning (hereinafter referred to as the blocking layer) consisting of toner and external additives at the nip between the intermediate transfer body and the cleaning blade. This blocking layer functions like a breakwater that prevents toner from entering. To form a blocking layer, toner is delivered to the nip portion between the cleaning component and the cleaning blade. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2016-031416 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, if, for example, an image forming apparatus capable of printing up to A3 size supplies toner to the entire circumferential area of ​​the intermediate transfer body at the contact point of the cleaning blade, the amount of toner consumed will be greater than in conventional configurations. Furthermore, if a toner image is formed around the entire circumferential direction of the intermediate transfer body, a large amount of toner will rush into the nip between the intermediate transfer body and the cleaning blade, and the pressure of the rushing toner may destroy the stop layer. As a result, toner will slip through the area where the stop layer is destroyed, leading to cleaning failures.

[0006] This invention was made under such circumstances, and aims to prevent cleaning defects even with low toner consumption, suppress uneven friction in a new intermediate transfer body, and prevent the cleaning blade from curling. [Means for solving the problem]

[0007] To solve the above-mentioned problems, the present invention has the following configuration.

[0008] (1) Equipment book body Prepare, Forming a toner image on the recording material An image forming apparatus that performs image forming operations, Photosensitive drum And, as stated above Surface of the photosensitive drum A means for charging, Charged by the aforementioned charging means The aforementioned The surface of the photosensitive drum A latent image forming means for forming an electrostatic latent image, and a latent image formed by the latent image forming means toner to supply toner The statue developing Developing Laura And the main body of the device In contrast Detachable can be , the above Photosensitive drum and contact possible Intermediate transfer body and the above Photosensitive drum The above toner A primary transfer means for transferring an image onto the intermediate transfer body, and on the intermediate transfer body toner A secondary transfer means for transferring an image to a recording material, and a means for contacting the intermediate transfer body death , on the intermediate transfer body toner A cleaning component for collecting, before The system includes control means for controlling the image formation operation, wherein the control means detects that the intermediate transfer body is new. In that case, An image pattern is formed on the intermediate transfer body, and the toner contained in the image pattern is controlled to be collected by the cleaning member. formed on the intermediate transfer body The image pattern is in a width direction perpendicular to the movement direction of the intermediate transfer body. In the first Toner image section and 1 A first toner image group in which non-toner image portions are arranged alternately, and in the width direction In the secondThe toner image portion and 2nd the non-toner image portion are arranged alternately, and a second toner image group adjacent to the first toner image group in the moving direction implied , The first toner image group and the second toner image group are, the 1 toner image portion and 、 the 2nd non-toner image portion 、 are In the direction of movement adjacent to each other, and the 1 non-toner image portion and 、 the 2nd toner image portion 、 are adjacent to each other in the moving direction, In the direction of movement being arranged side by side. The image forming apparatus is characterized by this. (2) An image forming apparatus that includes a device main body and performs an image forming operation of forming a toner image on a recording material, comprising: a photosensitive drum; charging means for charging the surface of the photosensitive drum; latent image forming means for forming an electrostatic latent image on the surface of the photosensitive drum charged by the charging means; a developing roller for supplying toner to the electrostatic latent image formed by the latent image forming means and developing a toner image; an intermediate transfer member that is detachable from the device main body and can contact the photosensitive drum; primary transfer means for transferring the toner image on the photosensitive drum to the intermediate transfer member; secondary transfer means for transferring the toner image on the intermediate transfer member to the recording material; a cleaning member that contacts the intermediate transfer member and recovers toner on the intermediate transfer member; a pair of regulating members for regulating skewing when the intermediate transfer member rotates; and control means for controlling the image forming operation. When the control means detects that the intermediate transfer member is new, it forms an image pattern on the intermediate transfer member and controls so that the toner included in the image pattern is recovered by the cleaning member. The image pattern formed on the intermediate transfer member includes a toner image group in which a first pattern in which one toner image portion and two or more non-toner image portions follow the toner image portion are repeatedly arranged in the width direction orthogonal to the moving direction of the intermediate transfer member. When the sum of the number of one toner image portion and two or more non-toner image portions in the first pattern is defined as a repetition period, a second pattern in which one toner image portion and two or more non-toner image portions arranged following the toner image portion are arranged in the repetition period is repeated in the moving direction, and a plurality of the toner image groups are arranged in the moving direction. When the length of one circumference of the developing roller is X, the length of the toner image portion in the moving direction is Y, the interval between adjacent toner image groups in the moving direction is Z, and a natural number is A, (X - Y) < A × (Y + Z) < (X + Y) is not satisfied, and the length of the toner image portion in the width direction is larger than the difference between the width direction length of the intermediate transfer member and the distance between the pair of regulating members. An image forming apparatus characterized by this.

Advantages of the Invention

[0010] According to the present invention, even with a small toner consumption amount, unevenness in the frictional force of a new intermediate transfer body can be suppressed without causing cleaning defects, and curling of the cleaning blade can be prevented.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0012] Exemplary modes for carrying out the present invention will be described while referring to the drawings.

Examples

[0013] [Overall structure] The printer 300 as an image forming apparatus will be described using Figure 1. Figure 1 is a diagram illustrating the overall configuration of the printer 300 according to this embodiment. In Figure 1, the horizontal direction is H, and the vertical direction perpendicular to the horizontal direction H is V. In this embodiment, the printer 300 is an electrophotographic color laser beam printer that forms an image on a sheet S as a recording material. The printer 300 has a main body (housing) 301A, a scanner (exposure device) 2, a control unit 3, and a door unit (opening / closing member) 20 that can be opened and closed relative to the main body 301A. Furthermore, the printer 300 has a sheet feeding unit 30, a transfer unit 40, a tray unit (moving unit, support unit) 50, and a fixing device 80. The part including the main body 301A and the door unit 20 can also be called the main frame 301. The main frame 301 includes the exterior of the printer 300. The main body of the device 301A houses a scanner 2, a control unit 3, a sheet feeding unit 30, a transfer unit 40, a tray unit 50, and a fixing device 80, which serve as latent image forming means.

[0014] The sheet feeding unit 30 has a loading tray 31 for loading sheets S and a supply roller 32. The loading tray 31 can be pulled out toward the door unit 20 to replenish the sheets S. The tray unit 50 has a tray (support member, drawer) 51 and cartridges PY, PM, PC, and PK. The tray 51 has a tray handle 52. The cartridges PY, PM, PC, and PK are removablely mounted on the tray 51.

[0015] Each of the cartridges PY, PM, PC, and PK is independently removable from the tray 51. Each cartridge contains yellow (Y), magenta (M), cyan (C), and black (K) toner (developer), respectively. The cartridges PY, PM, PC, and PK have the same configuration except for the color of the toner they contain. Therefore, the configuration and operation of one of the cartridges PY, PM, PC, or PK may be described, and the descriptions of the others may be omitted. Also, when there is no need to distinguish between cartridges PY, PM, PC, and PK, they may simply be referred to as cartridge P. The tray unit 50 can be said to have multiple cartridges P and a tray 51 into which the multiple cartridges P are removablely mounted.

[0016] In this embodiment, the tray unit 50 has a plurality of photosensitive drums (image carriers) 61, a plurality of charging rollers 62 as charging means, and a plurality of developing rollers 71 as developing means. Specifically, the tray unit 50 has four photosensitive drums 61, four charging rollers 62, and four developing rollers 71. The rotation axis direction of the photosensitive drums 61, the rotation axis direction of the developing rollers 71, and the rotation axis direction of the charging rollers 62 are parallel to each other. The rotation axis direction is perpendicular to the horizontal direction H and the vertical direction V, and is perpendicular to the plane of paper in Figure 1.

[0017] The part that forms the black (K) image is called the black station (first station), and the photosensitive drum 61 of the first station is called the first photosensitive drum, the developing roller 71 is called the first developing roller, and the charging roller 62 is called the first charging roller. The part that forms the cyan (C) image is called the cyan station (second station), and the photosensitive drum 61 of the second station is called the second photosensitive drum, the developing roller 71 is called the second developing roller, and the charging roller 62 is called the second charging roller. The part that forms the magenta (M) image is called the magenta station (third station), and the photosensitive drum 61 of the third station is called the third photosensitive drum, the developing roller 71 is called the third developing roller, and the charging roller 62 is called the third charging roller. The part that forms the yellow (Y) image is called the yellow station (fourth station), and the photosensitive drum 61 of the fourth station is called the fourth photosensitive drum, the developing roller 71 is called the fourth developing roller, and the charging roller 62 is called the fourth charging roller.

[0018] Cartridge PK is installed in the black station, cartridge PC in the cyan station, cartridge PM in the magenta station, and cartridge PY in the yellow station. In this embodiment, cartridge PK is referred to as the first cartridge, cartridge PC as the second cartridge, cartridge PM as the third cartridge, and cartridge PY as the fourth cartridge. The numbers 1st, 2nd, 3rd, and 4th are used for explanatory purposes only.

[0019] The photosensitive drum 61, the charging roller 62, and the developing roller 71 may be provided in either the cartridge P or the tray 51. In this embodiment, the cartridge P has the photosensitive drum 61, the charging roller 62, and the developing roller 71. In this embodiment, the diameter of the photosensitive drum 61 is 30 mm, the diameter of the charging roller 62 is 11 mm, and the diameter of the developing roller 71 is 16 mm. The length of one rotation of the developing roller 71, i.e., the circumference, is (16 × π) mm.

[0020] The transfer unit 40 includes an intermediate transfer belt 41 as an intermediate transfer body, a primary transfer roller 42, a cleaning section 43 for the intermediate transfer belt 41, a drive roller 46 for driving the intermediate transfer belt 41, and a tension roller (driven roller) 47. The transfer unit 40 also has restricting members 48 at both ends of the tension roller 47 to restrict the skewing of the intermediate transfer belt 41. More specifically, a pair of restricting members 48 are provided at both ends of the tension roller 47 in the direction of its rotation axis. The pair of restricting members 48 are members that restrict movement in the width direction (skew, meandering) when the intermediate transfer belt 41 moves in the direction of movement (circumferential direction, rotational direction, rotational direction). The width direction is perpendicular to the direction of movement of the intermediate transfer belt 41, and is also the direction of the rotation axis of the photosensitive drum 61, charging roller 62, developing roller 71, drive roller 46, and tension roller 47.

[0021] In this embodiment, the printer 300 is equipped with an optical sensor 44 that detects the toner image (developer image) transferred to the intermediate transfer belt 41. In this embodiment, the intermediate transfer belt 41 is positioned below the photosensitive drum 61, supported by a primary transfer roller 42 which serves as a primary transfer means, and is able to contact the photosensitive drum 61 so that a primary transfer portion is formed between the intermediate transfer belt 41 and the photosensitive drum 61. In this embodiment, the circumferential length of the intermediate transfer belt 41 is 792 mm, and the widthwise length is 346 mm. The distance between the pair of regulating members 48 at both ends of the tension roller 47 is 347.4 mm. That is, there is a predetermined gap (1.4 mm) between the pair of regulating members 48 and the intermediate transfer belt 41. The predetermined gap is also called the difference between the widthwise length of the intermediate transfer belt 41 and the distance between the regulating members 48. The circumferential direction is the direction of movement of the intermediate transfer belt 41.

[0022] The printer 300 has a secondary transfer roller 45 as a secondary transfer means that contacts the intermediate transfer belt 41 so that a secondary transfer section is formed. The secondary transfer section is formed between the intermediate transfer belt 41, which is supported by a drive roller 46, and the secondary transfer roller 45. The rotational axis directions of the primary transfer roller 42, the drive roller 46, the tension roller 47, and the secondary transfer roller 45 are parallel to each other. A pair of registration rollers 4 is positioned in front of (upstream of) the secondary transfer section in the conveying direction of the sheet S. Furthermore, the transfer unit 40 is detachable from the main body 301A independently of the tray unit 50 and can be replaced with a new transfer unit 40. The fixing device 80 has a fixing section 81 and a flapper 5. The fixing device 80 is configured to heat the sheet S. In this embodiment, the fixing section 81 includes a heating section (heating roller) including a heater and a pressurizing section (pressurizing roller).

[0023] The printer 300 is equipped with an operation display unit 420. The operation display unit 420 has a display device, such as an LCD panel, that informs the user of various information, and input devices, such as physical buttons and a touch panel for the LCD panel, that accept input operations from the user. The control unit 3 communicates with the operation display unit 420 to control the display content of the display device and receives information input via the input devices.

[0024] (Regarding the movement of the transfer unit and tray unit) The movement of the transfer unit 40 and the tray unit 50 will be explained using Figures 1 and 2. Figure 2(a) shows the printer 300 with the door unit 20 open (open state). Figure 2(b) shows the printer 300 with the tray unit 50 extended independently. Figure 2(c) shows the printer 300 with the transfer unit 40 extended independently. Note that only the reference numerals for the essential parts are shown in Figures 2(a) to 2(c).

[0025] The transfer unit 40 and the tray unit 50 are movable from the inside to the outside of the device body 301A. In the horizontal direction H, the device body 301A has a first end 1b1 with an opening 301A1 and a second end 1b2 opposite to the first end 1b1. The tray unit 50 is movable through the opening 301A1 to a first inner position inside the device body 301A and to a first outer position outside the device body 301A. The transfer unit 40 is movable through the opening 301A1 to a second inner position inside the device body 301A and to a second outer position outside the device body 301A. Figure 2(a) shows the state where the tray unit 50 is in the first inner position and the transfer unit 40 is in the second inner position. Figure 2(b) shows the state where the tray unit 50 is in the first outer position and the transfer unit 40 is in the second inner position. Figure 2(c) shows the state in which the tray unit 50 is in the first inner position and the transfer unit 40 is in the second outer position.

[0026] The opening 301A1 may include an opening through which the tray unit 50 passes and an opening through which the transfer unit 40 passes. When the transfer unit 40 moves from the second inner position to the second outer position, at least the intermediate transfer belt 41 moves, and at least a portion of the intermediate transfer belt 41 protrudes from the device body 301A toward the outside of the device body 301A (for example, Figure 2(c)).

[0027] The direction in which the tray unit 50 moves from the first inner position to the first outer position is called the tray withdrawal direction Dd1, and the direction opposite to the tray withdrawal direction Dd1 is called the tray mounting direction Da1. The tray withdrawal direction Dd1 can be described as the direction from the second end 1b2 to the first end 1b1.

[0028] The direction in which the transfer unit 40 moves from the second inner position to the second outer position is called the transfer extraction direction Dd2, and the direction opposite to the transfer extraction direction Dd2 is called the transfer mounting direction Da2. In the transfer extraction direction Dd2, the drive roller 46 is positioned downstream of the tension roller 47. The transfer extraction direction Dd2 can be described as the direction from the second end 1b2 to the first end 1b1.

[0029] The tray withdrawal direction Dd1 and the tray mounting direction Da1 are directions that intersect (preferably orthogonal to) the rotation axis direction of the photosensitive drum 61. The transfer withdrawal direction Dd2 and the transfer mounting direction Da2 are directions that intersect (preferably orthogonal to) the rotation axis direction of the drive roller 46. The rotation axis direction of the drive roller 46 is parallel to the rotation axis direction of the photosensitive drum 61.

[0030] The door unit 20, attached to the main body 301A of the device, is movable between a closed position and an open position. As shown in Figure 1, when the door unit 20 is in the closed position (closed state of the door unit 20), the door unit 20 covers the opening 301A1. As shown in Figure 2(a), when the door unit 20 is in the open position (open state of the door unit 20), the opening 301A1 is exposed.

[0031] As shown in Figure 1, when the door unit 20 is in the closed position, the door unit 20 covers the fixing device 80 attached to the main body 301A of the device. More specifically, when the door unit 20 is in the closed position, the upper cover portion 20b of the door unit 20, enclosed by the dotted line, is located above the fixing device 80. The upper cover portion 20b of the door unit 20 functions as part of the exterior.

[0032] The door unit 20 can move between an open and closed position while the fixing device 80 is supported by the device body 301A. In other words, the door unit 20 moves from the closed position to the open position so as to move away from the fixing device 80 supported by the device body 301A. Therefore, as shown in Figure 2(a), when the door unit 20 is in the open position, the door unit 20 is away from the fixing device 80 supported by the device body 301A. The transfer unit 40 and the tray unit 50 can move from inside to outside the device body 301A through the opening 301A1, and after moving, they are in the state shown in Figures 2(b) and 2(c).

[0033] With the tray unit 50 moved outside the main body 301A (Figure 2(b)), it is permissible to remove cartridges PY, PM, PC, and PK from the tray 51 and to install cartridges PY, PM, PC, and PK onto the tray 51. This allows cartridges PY, PM, PC, and PK to be replaced with new cartridges PY, PM, PC, and PK. In this embodiment, cartridge P is detachable from the tray 51 in a direction intersecting (preferably perpendicular to) the rotation axis of the photosensitive drum 61. Furthermore, each cartridge P can be replaced individually.

[0034] Cartridges PY, PM, PC, and PK are removed from tray 51 by moving them away from the transfer unit 40 relative to tray 51. In this embodiment, the transfer unit 40 is located below the tray unit 50. Therefore, cartridges PY, PM, PC, and PK are removed from tray 51 by moving them upward relative to tray 51. Furthermore, the transfer unit 40 can be removed from the main body 301A independently of the tray unit 50 and replaced with a new transfer unit 40.

[0035] [Image Formation Process] The image formation operation of the printer 300 will be explained using Figure 1. The control unit 3, which acts as a control means for the printer 300, starts the image formation operation on the sheet S based on the image signal received from the external host device 400. The external host device 400 is, for example, a personal computer, an image reader, and a facsimile machine.

[0036] When an image is formed on the sheet S, the fixing device 80 is in the use position, the tray unit 50 is in the first inner position, the transfer unit 40 is in the second inner position, and the door unit 20 is in the closed position. With the transfer unit 40 in the second inner position, the intermediate transfer belt 41 can come into contact with the photosensitive drum 61. At this time, the tray unit 50 is positioned above the transfer unit 40.

[0037] A charging voltage is applied to the charging roller 62, causing the photosensitive drum 61 to rotate. A laser corresponding to the image information is shone from the scanner 2 onto the photosensitive drum 61, exposing the surface of the photosensitive drum 61 that has been charged by the charging roller 62. As a result, an electrostatic latent image corresponding to the image information is formed on the surface of the photosensitive drum 61 (on the image carrier).

[0038] The developing roller 71 carries toner. A developing voltage is applied to the developing roller 71, and the electrostatic latent image formed on the photosensitive drum 61 is developed by the toner supplied from the developing roller 71, forming a toner image on the surface of the photosensitive drum 61. In this embodiment, the developing roller 71 develops the electrostatic latent image while in contact with the photosensitive drum 61, but the developing roller 71 may develop the electrostatic latent image with a gap between it and the photosensitive drum 61. When a full-color image is formed, toner images of each color are formed on each photosensitive drum 61.

[0039] In this embodiment, with the tray unit 50 in the first inner position, the developing roller 71 is movable between a contact position in contact with the photosensitive drum 61 and a separated position away from the photosensitive drum 61. Specifically, a switching device (not shown) provided in the main body 301A switches between the developing roller 71 being in the contact position and the developing roller 71 being in the separated position. This allows the developing roller 71 to be kept away from the photosensitive drum 61 when no image forming operation is being performed.

[0040] Furthermore, the printer 300 can perform monochrome printing. The developing roller 71K and photosensitive drum 61K corresponding to cartridge PK are in contact, while the developing rollers 71Y, 71M, and 71C and photosensitive drums 61Y, 61M, and 61C corresponding to cartridges PY, PM, and PC are separated. The printer 300 can also perform full-color printing with the photosensitive drum 61 corresponding to cartridge PY, PM, PC, and PK in contact with the intermediate transfer belt 41. The toner image formed on each photosensitive drum 61 is transferred to the intermediate transfer belt 41 (on the intermediate transfer body) by the primary transfer roller 42 in the primary transfer section, and then transported toward the secondary transfer section formed by the intermediate transfer belt 41 and the secondary transfer roller 45.

[0041] Meanwhile, the main body of the device 301A has a transport path 301c through which the sheet S heading toward the fixing device 80 passes. In the transport path 301c, there is a transfer unit support member 602, indicated by a diagonal line, but it is positioned so as not to interfere with the sheet S in the depth direction of Figure 1, and the transport of the sheet S is not obstructed by the transfer unit support member 60. In the sheet feeding section 30, one sheet S is separated and fed from the sheets S loaded on the loading tray 31 by the supply roller 32 at a predetermined timing, and is transported through the registration roller pair 4 toward the secondary transfer section and the fixing device 80.

[0042] In the secondary transfer section, the toner image is transferred from the intermediate transfer belt 41 to the sheet S. Toner that is not transferred to the sheet S is removed from the intermediate transfer belt 41 by a cleaning blade 95, which is a cleaning member provided in the cleaning section 43. The sheet S, on which the toner image has been transferred in the secondary transfer section, is transported toward the fuser 80. In the fuser 80, the sheet S is heated and pressurized in the fuser section 81, and the unfixed toner image is fixed to the sheet S. The sheet S, on which the toner image has been fixed, is transported toward the flapper 5, which is a path switching section.

[0043] The flapper 5 is movable between an discharge position that guides the sheet S, which has passed through the fuser 80, toward the discharge path 301d, and a reversal position that guides it toward the reversal path 301e. When single-sided printing is performed, in which an image is formed on one side of the sheet S, the sheet S is guided to the discharge path 301d by the flapper 5 and discharged into the discharge tray 1f formed on the upper part of the device body 301A. On the other hand, when double-sided printing is performed, in which an image is printed on one side (front) and the back side of the sheet S, the sheet S is guided to the reversal path 301e by the flapper 5. After the sheet S is guided into the reversal path 301e, the transport direction of the sheet S is reversed by the reversal roller pair 49, and the sheet S is transported through the double-sided transport path 20a formed in the door unit 20 toward the secondary transfer section. In the secondary transfer section, after the toner image is transferred to the back side of the sheet S, the sheet S passes through the fuser 80, is guided to the discharge path 301d by the flapper 5, and discharged into the discharge tray 1f of the device body 301A.

[0044] [Intermediate transfer belt] Next, the configuration of the intermediate transfer belt 41 in this embodiment will be described. Figure 3 is a schematic enlarged partial cross-sectional view of the intermediate transfer belt 41, cut in a direction substantially perpendicular to the circumferential direction of the intermediate transfer belt 41 (viewed along the direction of movement of the intermediate transfer belt 41). The intermediate transfer belt 41 is an endless intermediate transfer belt member (or film-like member) consisting of two layers: a base layer 82 and a surface layer 83. The surface layer 83 supports (holds) the toner transferred from the photosensitive drum 61. The base layer 82 is a 65 μm thick layer in which carbon black is dispersed as an electrical resistance modifier in polyethylene naphthalate resin. The surface layer 83 is a 3 μm thick layer in which zinc oxide antimond dope is dispersed as a conductive material 86 in acrylic resin as a base material 85, and polytetrafluoroethylene (PTFE) particles are added as a solid lubricant 84. The solid lubricant 84 added to the surface layer 83 forms protrusions, with at least a portion of it deposited on the outermost surface of the surface layer 83 and partially exposed, at least before the intermediate transfer belt 41 is put into use. In addition, the solid lubricant 84 added to the surface layer 83 is also dispersed in the substrate 85 of the surface layer 83.

[0045] [Method for manufacturing an intermediate transfer belt] Next, a method for producing the intermediate transfer belt 41 will be described. First, examples of materials used for the base layer 82 include thermoplastic resins such as polycarbonate, polyvinylidene fluoride (PVDF), polyethylene, polypropylene, polymethylpentene-1, polystyrene, polyamide, polysulfone, polyarylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyphenylene sulfide, polyethersulfone, polyethernitrile, thermoplastic polyimide, polyetheretherketone, thermotropic liquid crystal polymer, and polyamic acid. Two or more of these can also be used in combination. Furthermore, conductive materials and the like can be melt-kneaded into these thermoplastic resins, and then the base layer 82 of the intermediate transfer belt 41 can be obtained by appropriately selecting a molding method such as inflation molding, cylindrical extrusion molding, or blow molding.

[0046] On the other hand, for the surface layer 83, a curable material that hardens by heat or irradiation with energy rays such as ultraviolet light or electron beams can be suitably used from the viewpoint of increasing the hardness of the surface of the intermediate transfer belt 41 and improving durability (wear resistance). In particular, a curable material that hardens by irradiation with highly curable ultraviolet light or electron beams is preferred, but is not limited to these. Among the curable materials, organic materials include curable resins such as melamine resin, urethane resin, alkyd resin, acrylic resin, and fluorine-based curable resin (fluorine-containing curable resin). Inorganic materials include alkoxysilane / alkoxyzirconium-based materials and silicate-based materials. Organic-inorganic hybrid materials include inorganic fine particle dispersed organic polymer-based materials, inorganic fine particle dispersed organoalkoxysilane-based materials, acrylic silicon-based materials, and organoalkoxysilane-based materials. From the viewpoint of strength such as abrasion resistance and crack resistance of the surface layer 83 of the intermediate transfer belt 41, resin materials (curable resins) are preferred among curable materials, and among curable resins, acrylic resins obtained by curing an unsaturated double bond-containing acrylic copolymer are preferred. Unsaturated double bond-containing acrylic copolymers are available, for example, as Lucifural (trade name, manufactured by Nippon Paint Co., Ltd.), which is an acrylic-based ultraviolet-curable hard coat material. In other words, it is preferable that the intermediate transfer belt 41 has a surface layer (cured film, surface hardened layer) 83 obtained by curing a liquid containing ultraviolet-curable monomers and / or oligomer components by irradiating it with energy rays.

[0047] Furthermore, conductive materials (conductive fillers, electrical resistance adjusters) 86 can be added to the surface layer 83 for the purpose of adjusting electrical resistance. The conductive material 86 can be an electronically conductive material or an ionic conductive material. Examples of electronically conductive materials include particulate, fibrous, or flake-shaped carbon-based conductive fillers such as carbon black, PAN-based carbon fibers, and expanded graphite pulverized products. Other examples include particulate, fibrous, or flake-shaped metal-based conductive fillers such as silver, nickel, copper, zinc, aluminum, stainless steel, and iron. Other examples include particulate metal oxide-based conductive fillers such as zinc antimonate, antimond-doped tin oxide, antimond-doped zinc oxide, tin-doped indium oxide, and aluminum-doped zinc oxide. Examples of ionic conductive materials include ionic liquids, conductive oligomers, and quaternary ammonium salts. One or more of these conductive materials may be appropriately selected, and the electronically conductive material and the ionic conductive material may be mixed and used. Among these, particulate metal oxide-based conductive fillers are preferred because they require only a small amount of additive and allow for the desired surface smoothness of the surface layer 83.

[0048] Furthermore, a solid lubricant 84 can be added to the surface layer 83. The solid lubricant 84 can be appropriately selected from PTFE resin powder, trifluoroethylene chloride resin powder, tetrafluoroethylene hexafluoropropylene resin powder, vinyl fluoride resin powder, vinylidene fluoride resin powder, difluoroethylene chloride resin powder, fluorine-containing particles such as graphite fluoride, and copolymers thereof. The solid lubricant 84 is not necessarily limited to these, and may also be silicone resin particles, silica particles, molybdenum disulfide powder, etc. Among these, PTFE resin particles (such as emulsion polymerized PTFE resin particles) are preferred because they have a low coefficient of friction on the surface of the particles and can reduce wear on other components that come into contact with the surface layer 83 of the intermediate transfer belt 41, such as the cleaning blade 95.

[0049] [Cleaning section of the intermediate transfer belt] Figure 4(a) is a hypothetical cross-sectional view illustrating the mounting position of the cleaning blade 95 when it is not elastically deformed, and Figure 4(b) is a schematic cross-sectional view illustrating the configuration of the cleaning unit 43. The cleaning unit 43 includes a cleaning container 90 and a cleaning action unit 91 provided inside the cleaning container 90. The cleaning container 90 is configured as part of the frame of a transfer unit (not shown) having an intermediate transfer belt 41, etc. The cleaning action unit 91 includes a cleaning blade 95 as a cleaning member (contact member) and a support member 92 that supports the cleaning blade 95. The cleaning blade 95 is an elastic blade made of urethane rubber (polyurethane), which is an elastic material, and is supported in a state of being bonded to the support member 92 which is made of sheet metal using galvanized steel plate as the material.

[0050] The cleaning blade 95 is a long, plate-like member in the width direction of the intermediate transfer belt 41 (the longitudinal direction of the cleaning blade 95) that intersects with the direction of movement of the intermediate transfer belt 41 (hereinafter referred to as the conveying direction R). In the short direction, the cleaning blade 95 has its free end 95a in contact with the intermediate transfer belt 41, and its fixed end 95b fixed to the support member 92 by being bonded. The longitudinal length of the cleaning blade 95 is 326 mm, its thickness is 2 mm, and its hardness is 76° according to JIS A standards.

[0051] The cleaning unit 91 is configured to pivot relative to the surface of the intermediate transfer belt 41. Specifically, the support member 92 is pivotably supported relative to the surface of the intermediate transfer belt 41 via a pivot shaft 93 fixed to the cleaning container 90. The support member 92 is pulled by a tension spring 94, a biasing means provided in the cleaning container 90, causing the cleaning unit 91 to move around the pivot shaft 93, thereby biasing (pressing) the cleaning blade 95 against the intermediate transfer belt 41.

[0052] Opposite the cleaning blade 95, a drive roller 46, which also functions as a tension roller, is positioned on the inner circumference of the intermediate transfer belt 41. The cleaning blade 95 is in contact with the surface of the intermediate transfer belt 41 in a counter-direction with respect to the transport direction R, at a position opposite to the drive roller 46. That is, the cleaning blade 95 is in contact with the surface of the intermediate transfer belt 41 with its free end 95a in its short direction facing upstream in the transport direction R. As a result, as shown in Figure 4(b), a blade nip portion 96 (contact portion) is formed between the cleaning blade 95 and the intermediate transfer belt 41. At the blade nip portion 96, the cleaning blade 95 scrapes off residual toner from the surface of the moving intermediate transfer belt 41 and collects it in the cleaning container 90.

[0053] In this embodiment, the mounting position of the cleaning blade 95 is set as follows. As shown in Figure 4(a), the set angle θ is 23°, the penetration depth δ is 1.125 mm, and the contact pressure is 65 gf / cm. Here, the set angle θ is the angle between the tangent TL of the drive roller 46 and the cleaning blade 95 at the intersection Pi of the intermediate transfer belt 41 and the cleaning blade 95. More specifically, the set angle θ is the angle between the tangent TL of the drive roller 46 and the surface 95d of the cleaning blade 95. The penetration depth δ is the length in the thickness direction over which the cleaning blade 95 (more specifically, the free end surface 95c of the cleaning blade 95) overlaps with the drive roller 46. The contact pressure is defined as the pressing force from the cleaning blade 95 at the blade nip portion 96 (linear pressure in the longitudinal direction) and is measured using a film-type pressure measurement system (product name: PINCH, manufactured by Nitta Corporation).

[0054] When the intermediate transfer belt 41 and cleaning blade 95 are new, there is no toner in the blade nip portion 96, and it tends to be susceptible to the effects of uneven frictional resistance due to uneven surface roughness of the intermediate transfer belt 41. As a result, when the portion with high frictional resistance passes through the blade nip portion 96, the free end portion 95a of the cleaning blade 95 is pulled in the transport direction R of the intermediate transfer belt 41, causing the free end portion 95a to curl up towards the transport direction R of the intermediate transfer belt 41.

[0055] Therefore, the control unit 3 performs an operation to evenly dispense toner as a lubricant over the entire intermediate transfer belt 41 when the transfer unit 40 is new. This makes it possible to reduce unevenness in the frictional force of the intermediate transfer belt 41. With this configuration, it is possible to reduce unevenness in the frictional force caused by unevenness in the roughness of the intermediate transfer belt 41 in the blade nip section 96 and prevent curling.

[0056] [Inhibition layer at the blade nip] Figure 5 is a schematic cross-sectional view showing an enlarged view of the cleaning unit 43, indicating that the intermediate transfer belt 41 is rotating in the transport direction R (forward rotation). The cleaning blade 95 is flexible, and the blade nip portion 96 is in contact with the intermediate transfer belt 41 in a distorted state. This is because the blade nip portion 96 is in contact with the intermediate transfer belt 41 in a counter-direction relative to the transport direction R, and is pulled and wrapped around by the intermediate transfer belt 41 due to the shear force (arrow F) caused by the rotational motion of the intermediate transfer belt 41. As the load is concentrated on the part of the blade nip portion 96 that is wrapped around (hereinafter referred to as the curl-down portion 95e), the contact pressure on the surface of the intermediate transfer belt 41 increases.

[0057] In this state, when toner T adhering to the surface of the intermediate transfer belt 41 is sent to the cleaning unit 43, it is scraped off by the cleaning blade 95, and a portion of the toner T accumulates in the cleaning unit 43. It is known that fine particles (hereinafter referred to as external additives) are added to the surface of the toner T mainly to set the electrostatic charge and fluidity of the toner T to desired values. Due to the shear force (arrow F) between the cleaning blade 95 and the intermediate transfer belt 41, a portion of the external additive may peel off from the surface of the toner T. A mixture of the peeled-off portion of the external additive and toner T is interposed in an aggregated state between the curl-down section 95e and the intermediate transfer belt 41, forming a blocking layer Sp. It is generally known that this blocking layer Sp functions like a breakwater that prevents the intrusion of toner T.

[0058] [Toner ejection operation] The toner ejection operation onto the intermediate transfer belt 41 in this embodiment will now be described. After a new transfer unit 40 is detected, the control unit 3 evenly transfers a predetermined toner image onto the entire circumference of the intermediate transfer belt 41 by an image forming operation. At this time, the control unit 3 does not transport the sheet S and does not apply voltage to the secondary transfer roller 45, so that the toner image transported by the intermediate transfer belt 41 passes through the secondary transfer section without being transferred and reaches the cleaning section 43. As a result, the toner image that reaches the cleaning section 43 is collected by the cleaning blade 95, and toner is spread onto the intermediate transfer belt 41 at the positions where the toner image was transferred. As a result, the frictional resistance of the blade nip portion 96 of the cleaning blade 95 is reduced, and the unevenness of the surface roughness of the intermediate transfer belt 41 is reduced. In other words, the toner image that is not intended to be transferred to the sheet S functions as a lubricant. This operation is called the toner ejection operation. The toner image transferred onto the intermediate transfer belt 41 during the toner ejection operation will be referred to as the ejection image pattern below.

[0059] The toner ejection function can be effective regardless of which cartridge P toner is used. Furthermore, by using the cartridge P with the longest remaining lifespan (the one with the most life left) when performing the toner ejection function, the ejection process can be performed using toner with a relatively large amount of lubricants such as external additives, resulting in a greater lubrication effect.

[0060] [Detection of new transfer unit] The control unit 3 can detect when the transfer unit 40 has been replaced with a new one. For example, the transfer unit 40 may have a memory tag, and the memory tag may store identification information including whether or not the transfer unit 40 is new. If the transfer unit 40 is new, the memory tag will store information indicating that it is new. If the control unit 3 cannot read information from the memory tag, it can determine that the transfer unit 40 is not installed in the printer 300. If the control unit 3 can read information from the memory tag, it can determine that the transfer unit 40 is installed in the printer 300. Furthermore, the control unit 3 determines whether or not the transfer unit 40 is new based on the information read from the memory tag. Also, if a new transfer unit 40 is installed in the printer 300, the control unit 3 can write information to the memory tag indicating that it is not new.

[0061] Furthermore, the control unit 3 may detect that the transfer unit 40 has been replaced with a new one via the operation display unit 420. For example, the control unit 3 may display a question on the operation display unit 420 asking whether the transfer unit 40 has been replaced, and display "yes" or "no" buttons. The control unit 3 may detect whether the transfer unit 40 is new or not by having the user press the "yes" or "no" button and input information regarding whether or not it has been replaced with a new one via the operation display unit 420. In addition, the control unit 3 may determine whether the transfer unit 40 is new or not based on the phase of the gear of the drive roller 46. Here, since the phase of the gear of the drive roller 46 is different when the transfer unit 40 is new and when it is not new, the control unit 3 can determine whether the transfer unit 40 is new or not.

[0062] [Cartridge remaining life detection] The control unit 3 can detect the cartridge P with the most remaining life, in other words, the cartridge P with the most toner remaining, by, for example, the following method. The control unit 3 measures the pixel information (number of pixel signals (video count value)) of the output image (image portion of the electrostatic latent image) formed on the sheet S by the image forming operation, and can acquire the remaining toner amount based on the measured video count value (video count method). The control unit 3 may also use known toner amount detection methods such as the capacitance method, light transmission method (optical detection method), weight detection method, and material surface detection method. The capacitance method, for example, uses an electrode (conductive member) attached to the inner wall of the container containing the toner, whose capacitance changes in accordance with changes in the state of the toner in the cartridge P, and detects the amount of toner based on the change in the detected capacitance. The light transmission method uses a light source that irradiates light into the inside of the cartridge P, and a light receiving unit that receives the light that has passed through the inside of the cartridge P, and detects the amount of toner based on the change in the light receiving state of the light receiving unit. The weight detection method is a method that detects the amount of toner in the cartridge P based on the weight of the cartridge P containing the toner. The toner level detection method is a method of detecting the amount of toner in cartridge P based on the position (height) of the toner surface within cartridge P. Toner level detection methods such as the video count method, capacitive method, light transmission method, weight detection method, and toner level detection method may be used individually or in combination. Specifically, for example, when the remaining toner amount obtained by the video count method falls below a predetermined amount, other methods such as the capacitive method or light transmission method can be used.

[0063] [Output image pattern of this embodiment] The ejection image pattern of this embodiment will be described. Here, let the length of one circumference of the developing roller 71 be X, and A be a natural number (positive integer, A = 1, 2, 3,...). Also, let the length in the width direction of the intermediate transfer belt 41 be W1, and the distance between a pair of regulating members 48 (between the regulating members) be L1. Although details will be described later, the ejection image pattern of this embodiment includes a plurality of toner images (hereinafter also referred to as toner image portions) and portions without toner image portions (hereinafter also referred to as non-toner image portions) (see Fig. 6(a)). Here, let the circumferential length of one toner image (toner image portion) included in the ejection image pattern be Y, the interval between adjacent toner image portions in the circumferential direction be Z, and the length in the width direction of one toner image (toner image portion) included in the ejection image pattern be W. The length Y, interval Z, and width W of the ejection image pattern of this embodiment are determined so as not to satisfy the following formula (1) and to satisfy formula (2). (X - Y) < A×(Y + Z) < (X + Y) Formula (1) W > L1 - W1 Formula (2)

[0064] Formula (1) is a conditional formula for preventing the ejection image pattern from being formed at the same position of the developing roller 71 after the second rotation of the developing roller 71. More specifically, it is a conditional formula for preventing toner from being applied to the photosensitive drum 61 at the same position of the developing roller 71 when forming the ejection image pattern, and it eliminates the periodicity due to the rotation of the developing roller 71. Formula (2) eliminates the influence of the skew of the intermediate transfer belt 41 on the formation of the ejection image pattern by making the width W of the toner image included in the ejection image pattern larger than the difference between the distance L1 between the regulating members 48 and the length W1 in the width direction of the intermediate transfer belt 41.

[0065] Therefore, the length W in the width direction of one toner image included in the ejection image pattern may be, for example, 5 mm or more and 15 mm or less. Also, the circumferential length Y of one toner image included in the ejection image pattern may be 0.5 mm or more and 1.5 mm or less. Further, the interval Z between two toner images arranged in the circumferential direction may be 10 mm or more and 15 mm or less.

[0066] [Explanation of effects] When the cleaning blade 95 is lifted, toner can pass through the lifted area and reach the secondary transfer area, causing vertical bands to appear on the image. Also, when the blocking layer Sp is destroyed at the blade nip portion 96, toner can pass through a portion of the destroyed blocking layer Sp and reach the secondary transfer area, causing vertical streaks to appear on the image.

[0067] This section describes verification experiments to examine the effectiveness of the toner ejection process against vertical bands caused by cleaning failures due to the peeling of the cleaning blade 95 and vertical streaks caused by cleaning failures due to the destruction of the blocking layer Sp of the blade nip portion 96. Five different ejection image patterns were prepared for the example and comparative example to conduct the verification experiments.

[0068] Figure 6 shows a cropped portion of the ejected image pattern for this embodiment and Comparative Examples 1-4. In reality, the ejected image pattern is evenly (uniformly) formed in the width direction of the intermediate transfer belt 41 (right side in Figure 6) and over one full turn (bottom side in Figure 6). With respect to one toner image (toner image portion) in the ejected image pattern, as described above, W is the length in the width direction of the intermediate transfer belt 41, Y is the length in the transport direction R, and Z is the circumferential spacing between adjacent toner image portions in the transport direction R. Figure 6(a) corresponds to this embodiment, and Figures 6(b) to 6(e) correspond to Comparative Examples 1-4, respectively. Table 1 shows the specific values ​​of W, Y, and Z. [Table 1]

[0069] This embodiment is a dashed line ejection image pattern that extends in the width direction of the intermediate transfer belt 41, with toner image sections Ta and non-toner image sections Tb alternating. The width direction length W of the toner image section Ta and the width direction length of the non-toner image section Tb are equal. As shown in Table 1, the toner image section Ta has W=10mm and Y=1mm. Also, Z=13mm, that is, the distance between toner image sections Ta1 and Ta2 that are aligned (adjacent) in the transport direction R is 13mm. Furthermore, the toner image section Ta3 is located between toner image sections Ta1 and Ta2 in the transport direction R. More specifically, in the transport direction R, the toner image section Ta3 is formed 6mm upstream from toner image section Ta1 in the transport direction R and 6mm downstream from toner image section Ta2 in the transport direction R.

[0070] These dashed line ejection image patterns are adjacent to each other at regular intervals in the transport direction R of the intermediate transfer belt 41, and the relative positions of the toner image portion Ta and the non-toner image portion Tb are reversed between adjacent dashed line ejection image patterns. More specifically, as shown in Figure 6(a), a group of toner image portions Ta and non-toner image portions Tb arranged alternately in the width direction (dashed line) is called the toner image group Tn1 (first toner image group). The toner image group adjacent to the toner image group Tn1 in the movement direction (transport direction R) is called the toner image group Tn2 (second toner image group). In this case, the toner image group Tn1 and the toner image group Tn2 are formed such that the toner image portion Ta and non-toner image portion Tb are adjacent to each other; in other words, the toner image portions Ta are not adjacent to each other, and the non-toner image portions Tb are not adjacent to each other. That is, the ejection image pattern has multiple toner image groups Tn1 and Tn2 alternating in the transport direction R. The output image pattern in this embodiment is arranged in a staggered pattern.

[0071] In Figure 6(a), the toner image portion Ta and the non-toner image portion Tb are arranged as Ta, Tb, Ta, Tb, ... (with a predetermined repetition period of 2), but this is not the only option. Within the range in which the length Y, spacing Z, and width W are determined so as not to satisfy equation (1) and yet satisfy equation (2), the following arrangements may be made: For example, the toner image portion Ta and the non-toner image portion Tb may be arranged as Ta, Tb, Tb, Ta, Tb, Tb, ... (with a predetermined repetition period of 3). Furthermore, in the transport direction R, three consecutive toner image groups may be arranged so that the toner image portions Ta and non-toner image portions do not adjoin each other. The predetermined repetition period may also be 4 or more, in which case, four or more consecutive toner image groups may be arranged so that the toner image portions Ta and non-toner image portions do not adjoin each other.

[0072] Comparative Example 1 has a dashed line ejection image pattern similar to that of this embodiment, but the positional relationship between the toner image portion Tc and the non-toner image portion Td of adjacent dashed line ejection image patterns in the transport direction R of the intermediate transfer belt 41 is the same. That is, in the toner image group Tn4 and the toner image portion Tn5, the toner image portions Tc are adjacent to each other, and the non-toner image portions Td are adjacent to each other. As shown in Table 1, the toner image portion Tc is W=10mm, Y=1mm, Z=6mm. The ejection image pattern of Comparative Example 1 is arranged in a grid pattern.

[0073] Comparative Example 2 is an ejected image pattern in which a solid linear toner image portion Te extending in the width direction of the intermediate transfer belt 41 is transferred around the intermediate transfer belt 41 at regular intervals. As shown in Table 1, the toner image portion Te has a width of W=320mm, Y=1mm, and Z=6mm. Comparative Example 3 is an ejected image pattern in which a toner image area Tf of a halftone pattern with a density of 60h is transferred over the entire width and circumferential area of ​​the intermediate transfer belt 41. As shown in Table 1, the toner image area Tf is W=320mm and Y=792mm. Since Comparative Example 3 is not a repeating pattern, Z is not set. Comparative Example 4 is an ejected image pattern in which a toner image area Tg of a full black pattern is transferred over the entire width and circumferential area of ​​the intermediate transfer belt 41. As shown in Table 1, the toner image area Tg is W=320mm and Y=792mm. Since Comparative Example 4 is not a repeating pattern, Z is not set. These ejection image patterns were used in the toner ejection operation when a new transfer unit 40 was detected, and their effectiveness was confirmed.

[0074] The verification experiment was conducted under conditions of 15°C and 10% humidity. With the main unit's power OFF, a new transfer unit was installed. After turning the power ON, one 60h halftone image was printed, and the presence or absence of vertical bands and streaks caused by cleaning failure was checked. Table 2 summarizes the toner consumption (mg), presence or absence of vertical bands, and presence or absence of vertical streaks caused by cleaning failure in this experiment. ○ indicates that no vertical bands or streaks occurred, and × indicates that no vertical bands or streaks occurred. [Table 2]

[0075] The experimental results showed that this embodiment did not produce curling or vertical streaks. The reason why the cleaning blade 95 did not curl was that lubricants such as toner and external additives could be applied to the entire surface of the intermediate transfer belt 41. As a result, unevenness in frictional force across the entire surface of the intermediate transfer belt 41 was reduced, and the tip of the cleaning blade 95 did not get caught in the transport direction R of the intermediate transfer belt 41. Furthermore, the reason why vertical streaks did not occur was that the amount of toner consumed (66.6 mg) was small. As a result, the total amount of toner that entered the blade nip portion 96 between the intermediate transfer belt 41 and the cleaning blade 95 was small, and cleaning was possible without damaging the barrier layer Sp.

[0076] Comparative Example 2 did not produce vertical streaks, but it did produce curling. The reason vertical streaks did not occur was that the amount of toner consumed (66.6 mg) was small, and the total amount of toner that entered the blade nip portion 96 between the intermediate transfer belt 41 and the cleaning blade 95 was small, so cleaning was possible without damaging the barrier layer Sp. On the other hand, the curling of the cleaning blade 95 occurred because the positional relationship between the toner image portion Tc and the non-toner image portion Td of adjacent dashed line ejection image patterns in the transport direction R of the intermediate transfer belt 41 was the same. As a result, the toner and external additives used as lubricants could not be applied uniformly in the width direction. In the parts of the intermediate transfer belt 41 where lubricant could not be applied in the width direction, the unevenness of the frictional force in the blade nip portion 96 could not be sufficiently reduced, so the tip of the cleaning blade 95 was pulled in the transport direction of the intermediate transfer belt 41, causing curling.

[0077] In Comparative Example 3, no peeling of the cleaning blade 95 occurred, but vertical streaks did occur. The reason no peeling occurred was that the toner image portion Te was a solid line extending in the width direction of the intermediate transfer belt 41, which reduced unevenness in frictional force across the entire surface of the intermediate transfer belt 41. The reason vertical streaks occurred was that a larger amount of toner was consumed compared to this embodiment (133.2 mg), and the total amount of toner that entered the intermediate transfer belt 41 and the blade nip portion 96 of the cleaning blade 95 was also larger. As a result, the pressure when the toner entered destroyed the barrier layer Sp.

[0078] In Comparative Example 4, while no peeling of the cleaning blade 95 occurred, vertical streaks did occur. The reason peeling did not occur was that the toner image portion Tf was a halftone pattern that applied toner to the entire surface of the intermediate transfer belt 41, which reduced unevenness in frictional force across the entire surface of the intermediate transfer belt 41. On the other hand, vertical streaks occurred because the amount of toner consumed was approximately five times greater than in this embodiment (350.7 mg), and the total amount of toner that entered the blade nip portion 96 between the intermediate transfer belt 41 and the cleaning blade 95 was also greater. As a result, the pressure when the toner entered destroyed the barrier layer Sp.

[0079] In Comparative Example 5, while no peeling of the cleaning blade 95 occurred, vertical streaks did occur. The reason peeling did not occur was that the toner image area Tg was an all-black pattern that coated the entire surface of the intermediate transfer belt 41 with toner, which reduced unevenness in frictional force across the entire surface of the intermediate transfer belt 41. On the other hand, vertical streaks occurred because the amount of toner consumed was approximately 14 times greater than in this embodiment (931.7 mg), and the total amount of toner that entered the blade nip portion 96 between the intermediate transfer belt 41 and the cleaning blade 95 was also greater. As a result, the pressure when the toner entered destroyed the barrier layer Sp.

[0080] As explained above, when a new transfer unit 40 is detected, an operation is performed to eject a predetermined ejection image pattern (Figure 6(a)) onto the entire surface of the intermediate transfer belt 41. This reduces unevenness in frictional force at the blade nip section 96 with a small amount of toner consumption, and prevents cleaning defects caused by curling of the cleaning blade 95. Furthermore, by performing this operation with a small amount of toner consumption, cleaning defects caused by damage to the blocking layer Sp can also be prevented. As a result, it is possible to take measures against image defects while keeping the amount of toner consumed down.

[0081] As described above, according to this embodiment, even with low toner consumption, cleaning defects can be avoided, unevenness in the frictional force of a new intermediate transfer body can be suppressed, and curling of the cleaning blade can be prevented.

[0082] <Other Embodiments> The present invention can also be realized by supplying a program that implements one or more of the functions of the above embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0083] This embodiment includes the following configuration. (Composition 1) An image forming apparatus that performs image forming operations and is equipped with multiple cartridges that can be attached to and detached from the main body of the apparatus, Image carrier and, A charging means for charging the image carrier, A latent image forming means for forming an electrostatic latent image on the image carrier, A developing means that supplies a developer to the electrostatic latent image formed by the latent image forming means and forms a developer image, An intermediate transfer body that is detachable from the main body of the apparatus and comes into contact with the image carrier, A primary transfer means for transferring the developer image on the image carrier to the intermediate transfer body, A secondary transfer means for transferring the developer image on the intermediate transfer body to a recording material, A cleaning member that contacts the intermediate transfer body and collects the developer on the intermediate transfer body, A pair of restricting members that restrict the slanting of the intermediate transfer body when it rotates, Control means for controlling the image forming operation, Equipped with, The control means, only when it detects that the intermediate transfer body is new, forms an image pattern on the intermediate transfer body that includes a toner image portion where a toner image is formed and a non-toner image portion where no toner image is formed, and does not transfer to the recording material, and controls the cleaning member to recover the toner contained in the image pattern. The aforementioned image pattern is The intermediate transfer body comprises a first toner image group in which the toner image portion and the non-toner image portion are alternately arranged in a width direction perpendicular to the movement direction of the intermediate transfer body, and a second toner image group in which the toner image portion and the non-toner image portion are alternately arranged in the width direction and adjacent to the first toner image group in the movement direction, The first toner image group and the second toner image group are arranged such that the toner image portion of the first toner image group and the non-toner image portion of the second toner image group are adjacent to each other, and the non-toner image portion of the first toner image group and the toner image portion of the second toner image group are adjacent to each other in the direction of movement. An image forming apparatus characterized by the following: (Configuration 2) The aforementioned image pattern is defined such that X is the length of one lap of the developing means, Y is the length of the toner image portion in the direction of movement, Z is the distance between adjacent toner image portions in the direction of movement, and A is a natural number. (XY) <A×(Y+Z)<(X+Y) Does not satisfy, The image forming apparatus according to configuration 1, characterized in that it is a picture forming apparatus. (Composition 3) The image pattern is such that the length of the toner image portion in the width direction is greater than the difference between the length of the intermediate transfer body in the width direction and the distance between the pair of regulating members. An image forming apparatus according to configuration 1 or configuration 2, characterized by the above. (Composition 4) The toner image portion has a length in the width direction of 5 mm or more and 15 mm or less. An image forming apparatus according to any one of configurations 1 to 3, characterized by the above. (Composition 5) The toner image portion has a length in the direction of movement of 0.5 mm or more and 1.5 mm or less. An image forming apparatus according to any one of configurations 1 to 4, characterized by the above. (Composition 6) The distance between adjacent toner image portions in the aforementioned direction of movement is 10 mm or more and 15 mm or less. An image forming apparatus according to any one of configurations 1 to 5, characterized by the above. (Composition 7) The control means forms the image pattern using the cartridge with the remaining lifespan among the plurality of cartridges. An image forming apparatus according to any one of configurations 1 to 6, characterized by the above. (Composition 8) The cleaning member has a blade that contacts the intermediate transfer body so as to face the upstream side in the direction of movement. An image forming apparatus according to any one of configurations 1 to 7, characterized by the above. (Composition 9) The aforementioned intermediate transfer body has a surface layer that carries the developer image, and has a surface layer in which a conductive material is dispersed on a substrate and a solid lubricant is added. An image forming apparatus according to any one of configurations 1 to 8, characterized by the above. (Composition 10) An image forming apparatus that performs image forming operations and is equipped with multiple cartridges that can be attached to and detached from the main body of the apparatus, Image carrier and, A charging means for charging the image carrier, A latent image forming means for forming an electrostatic latent image on the image carrier, A developing means that supplies a developer to the electrostatic latent image formed by the latent image forming means and forms a developer image, An intermediate transfer body that is detachable from the main body of the apparatus and comes into contact with the image carrier, A primary transfer means for transferring the developer image on the image carrier to the intermediate transfer body, A secondary transfer means for transferring the developer image on the intermediate transfer body to a recording material, A cleaning member that contacts the intermediate transfer body and collects the developer on the intermediate transfer body, A pair of restricting members that restrict the slanting of the intermediate transfer body when it rotates, Control means for controlling the image forming operation, Equipped with, When the control means detects that the intermediate transfer body is new, it forms an image pattern on the intermediate transfer body that includes a toner image portion where a toner image is formed and a non-toner image portion where no toner image is formed, and which is not transferred to the recording material, and controls the image pattern to be recovered by the cleaning member. The aforementioned image pattern is The intermediate transfer body has a plurality of toner image groups in which the toner image portion and the non-toner image portion are arranged in a width direction perpendicular to the movement direction at a predetermined repeating period, and the plurality of toner image groups are repeatedly arranged in the movement direction at the same period as the predetermined repeating period. In the aforementioned direction of movement, adjacent toner image groups are arranged so that the toner image portion and the non-toner image portion are adjacent to each other. When the length of one lap of the developing means is X, the length of the toner image portion in the direction of movement is Y, the distance between adjacent toner image portions in the direction of movement is Z, and A is a natural number, (XY) <A×(Y+Z)<(X+Y) The following conditions are not met, and the length of the toner image portion in the width direction is greater than the difference between the length of the intermediate transfer body in the width direction and the distance between the pair of regulating members. An image forming apparatus characterized by the following: [Explanation of symbols]

[0084] 3. Control Unit 41 Intermediate transfer belt 48 Regulating members 71 Developing roller P Cartridge

Claims

1. An image forming apparatus comprising a main unit and performing an image forming operation to form a toner image on a recording material, Photosensitive drum and A charging means for charging the surface of the photosensitive drum, A latent image forming means for forming an electrostatic latent image on the surface of the photosensitive drum that has been charged by the charging means, A developing roller that supplies toner to the electrostatic latent image formed by the latent image forming means and develops the toner image, An intermediate transfer body that is detachable from the main body of the apparatus and can come into contact with the photosensitive drum, A primary transfer means for transferring the toner image on the photosensitive drum to the intermediate transfer medium, A secondary transfer means for transferring the toner image on the intermediate transfer body to a recording material, A cleaning member that contacts the intermediate transfer body and collects toner from the intermediate transfer body, Control means for controlling the image forming operation, Equipped with, The control means, upon detecting that the intermediate transfer body is new, controls the formation of an image pattern on the intermediate transfer body and the recovery of toner contained in the image pattern by the cleaning member. The image pattern formed on the intermediate transfer material is The intermediate transfer body includes a first toner image group in which first toner image portions and first non-toner image portions are arranged alternately in a width direction perpendicular to the movement direction of the intermediate transfer body, and a second toner image group in which second toner image portions and second non-toner image portions are arranged alternately in the width direction and adjacent to the first toner image group in the movement direction, The first toner image group and the second toner image group are arranged in the direction of movement such that the first toner image portion and the second non-toner image portion are adjacent to each other in the direction of movement, and the first non-toner image portion and the second toner image portion are adjacent to each other in the direction of movement. An image forming apparatus characterized by the following:

2. The image pattern is defined as follows, where X is the length of one rotation of the developing roller, Y is the length of the first toner image portion and the second toner image portion in the direction of movement, Z is the distance between adjacent first toner image groups and second toner image groups in the direction of movement, and A is a natural number. (X-Y)<A×(Y+Z)<(X+Y) Does not satisfy, The image forming apparatus according to feature 1.

3. comprising a pair of restricting members that restrict the oblique movement of the intermediate transfer body when it rotates, The image pattern is such that the length in the width direction of the first toner image portion and the second toner image portion is greater than the difference between the length in the width direction of the intermediate transfer body and the distance between the pair of regulating members. The image forming apparatus according to feature 1.

4. The first toner image section and the second toner image section have a length in the width direction of 5 mm or more and 15 mm or less. The image forming apparatus according to feature 1.

5. The first toner image portion and the second toner image portion have a length in the direction of movement of 0.5 mm or more and 1.5 mm or less. The image forming apparatus according to feature 1.

6. The distance between adjacent first toner image groups and second toner image groups in the aforementioned direction of movement is 10 mm or more and 15 mm or less. The image forming apparatus according to feature 1.

7. The device body is equipped with a plurality of cartridges that can be attached to and detached from it, The control means forms the image pattern using the cartridge with the remaining lifespan among the plurality of cartridges. The image forming apparatus according to feature 1.

8. The cleaning member has a blade that contacts the intermediate transfer body so as to face the upstream side in the direction of movement. The image forming apparatus according to feature 1.

9. The aforementioned intermediate transfer body has a surface layer that carries a toner image, and the surface layer is formed by dispersing a conductive material on a substrate and adding a solid lubricant. The image forming apparatus according to feature 1.

10. An image forming apparatus comprising a main unit and performing an image forming operation to form a toner image on a recording material, Photosensitive drum and A charging means for charging the surface of the photosensitive drum, A latent image forming means for forming an electrostatic latent image on the surface of the photosensitive drum that has been charged by the charging means, A developing roller that supplies toner to the electrostatic latent image formed by the latent image forming means and develops the toner image, An intermediate transfer body that is detachable from the main body of the apparatus and can come into contact with the photosensitive drum, A primary transfer means for transferring the toner image on the photosensitive drum to the intermediate transfer medium, A secondary transfer means for transferring the toner image on the intermediate transfer body to a recording material, A cleaning member that contacts the intermediate transfer body and collects toner from the intermediate transfer body, A pair of restricting members that restrict the slanting of the intermediate transfer body when it rotates, Control means for controlling the image forming operation, Equipped with, The control means, upon detecting that the intermediate transfer body is new, controls the formation of an image pattern on the intermediate transfer body and the recovery of toner contained in the image pattern by the cleaning member. The image pattern formed on the intermediate transfer material is The toner image group includes a toner image group in which a first pattern is repeatedly arranged in the width direction perpendicular to the movement direction of the intermediate transfer body, in which one toner image portion is followed by two or more non-toner image portions. When the sum of the number of toner image units and two or more non-toner image units in the first pattern is called the repetition period, When viewed in the aforementioned direction of movement, a plurality of toner image groups are arranged in the aforementioned direction of movement such that a second pattern is repeated in the aforementioned direction of movement, in which one toner image portion and two or more non-toner image portions arranged following the toner image portion are arranged in the aforementioned repeating period. When the length of one rotation of the developing roller is X, the length of the toner image portion in the direction of movement is Y, the distance between adjacent toner image groups in the direction of movement is Z, and A is a natural number, (X-Y)<A×(Y+Z)<(X+Y) The following conditions are not met, and the length of the toner image portion in the width direction is greater than the difference between the length of the intermediate transfer body in the width direction and the distance between the pair of regulating members. An image forming apparatus characterized by the following:

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