Sensor cleaning apparatus and image forming apparatus

Abstract

To suppress re-adhesion of a foreign matter to a surface of a sensor when a cleaning member returns to an original position through the surface of the sensor in comparison to a case where the cleaning member cleans the surface of the sensor by moving the foreign matter only in the wiping direction in a sensor cleaning device in which the cleaning member returns to the original position after wiping the surface of the sensor.SOLUTION: A sensor cleaning device 54 comprises: a cleaning member 70 which cleans the entire surface 62 of a sensor 60 by wiping it while moving in the longitudinal direction of the surface 62 of the sensor 60 with respect to the surface 62 of the sensor 60 having a long side part 62L along the longitudinal direction and a short side part 62S along the short side direction intersecting the longitudinal direction, and includes an inclined part which is obliquely arranged with respect to the wiping direction such that an upstream side end in the wiping direction is located on the outer side in the short side direction of the surface 62 of the sensor 60; and a movement mechanism 58 which moves the cleaning member 70 in the wiping direction and the opposite direction to the wiping direction.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a sensor cleaning device and an image forming apparatus.

Background Art

[0002] An image forming apparatus that cleans the surface (detection surface) of a sensor by reciprocating (sliding) a cleaning member has been conventionally known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a sensor cleaning device in which a cleaning member wipes the surface of a sensor and returns to its original position, compared with a case where the cleaning member moves foreign matters only in the wiping direction to clean the surface of the sensor, when the cleaning member passes through the surface of the sensor and returns to its original position, it is an object of the present invention to suppress reattachment of foreign matters to the surface of the sensor.

Means for Solving the Problems

[0005] To achieve the above object, a sensor cleaning device according to a first aspect of the present invention wipes and cleans the entire surface of a sensor while moving in the longitudinal direction of the surface of the sensor, with respect to the surface of the sensor having a long side portion along the longitudinal direction and a short side portion along the short direction intersecting the longitudinal direction, and has a cleaning member having an inclined portion disposed obliquely with respect to the wiping direction such that an upstream end portion in the wiping direction is located outside the short direction of the surface of the sensor, and a moving mechanism that moves the cleaning member in the wiping direction and in a direction opposite to the wiping direction.

[0006] Furthermore, a second embodiment of the sensor cleaning device according to the present invention is a sensor cleaning device according to the first embodiment, wherein the cleaning member is formed asymmetrically with respect to the center line along the longitudinal direction of the surface of the sensor, and the moving mechanism moves the cleaning member in the wiping direction until at least the inclined portion of the cleaning member reaches the other corner beyond one corner on the downstream side in the wiping direction of the surface of the sensor.

[0007] Furthermore, a third embodiment of the sensor cleaning device according to the present invention is a sensor cleaning device according to the second embodiment, wherein the cleaning member is formed in a rectangular shape with the direction along the inclined portion as the longitudinal direction.

[0008] Furthermore, a fourth embodiment of the sensor cleaning device according to the present invention is a sensor cleaning device according to the third embodiment, wherein when the length of the short side portion downstream in the wiping direction of the surface of the sensor is L, and the angle of the inclined portion with respect to the short side portion is θ, the moving mechanism moves the cleaning member in the wiping direction until the intersection point where the intermediate portion of the inclined portion and the long side portion of the surface of the sensor intersect when the inclined portion of the cleaning member reaches the short side portion is at least L × tanθ away from the short side portion.

[0009] Furthermore, a fifth embodiment of the sensor cleaning device according to the present invention is a sensor cleaning device according to the first embodiment, wherein the cleaning member is formed symmetrically with respect to a center line along the longitudinal direction of the surface of the sensor and has a plurality of inclined portions, and the moving mechanism moves the cleaning member in the wiping direction until at least the plurality of inclined portions of the cleaning member each reach a corner on the downstream side of the wiping direction of the surface of the sensor.

[0010] Furthermore, a sixth embodiment of the sensor cleaning device according to the present invention is a sensor cleaning device according to the fifth embodiment, wherein the cleaning member has a plurality of inclined portions that are flared outwards from each other, from the downstream side to the upstream side in the wiping direction of the surface of the sensor.

[0011] Furthermore, a sensor cleaning device according to a seventh aspect of the present invention is a sensor cleaning device according to a sixth aspect, wherein when the length of the short side portion downstream in the wiping direction of the surface of the sensor is L, and the angle of the inclined portion with respect to the short side portion is θ, the moving mechanism moves the cleaning member in the wiping direction until the intersection point where the intermediate portion of the inclined portion and the long side portion of the surface of the sensor intersect when the inclined portion of the cleaning member reaches the short side portion is at least (L / 2) × tanθ away from the short side portion.

[0012] Furthermore, the image forming apparatus according to the eighth embodiment of the present invention includes a sensor for detecting the density of a toner density detection pattern, and a sensor cleaning apparatus according to any of the first to seventh embodiments for wiping and cleaning the surface of the sensor. [Effects of the Invention]

[0013] According to the first embodiment of the invention, in a sensor cleaning device in which a cleaning member wipes the surface of a sensor and returns to its original position, compared to a case in which the cleaning member moves foreign matter only in the wiping direction to clean the surface of the sensor, it is possible to suppress the re-adhesion of foreign matter to the surface of the sensor when the cleaning member passes over the surface of the sensor and returns to its original position.

[0014] According to the second embodiment of the invention, the moving mechanism can suppress the retention of foreign matter on the surface of the sensor compared to the case where the cleaning member is moved only to one corner on the downstream side of the sensor surface in the wiping direction, with its inclined portion.

[0015] According to the third embodiment of the invention, the contact load of the cleaning member on the surface of the sensor can be reduced compared to the case where the cleaning member is formed in a square shape that is longer than the short side of the surface of the sensor.

[0016] According to the fourth embodiment of the invention, when the inclined portion of the cleaning member reaches the short side of the sensor surface, the moving mechanism can reduce the contact load of the cleaning member on the sensor surface while scattering any foreign matter remaining on the sensor surface outwards in the short-side direction of the sensor surface, compared to the case where the cleaning member is only moved in the wiping direction to a position within L × tanθ from the short side.

[0017] According to the fifth embodiment of the invention, the moving mechanism can suppress the retention of foreign matter on the surface of the sensor compared to the case where the moving mechanism moves the cleaning member having a plurality of inclined portions only to a position where each of the plurality of inclined portions does not reach the corner on the downstream side in the wiping direction of the sensor surface.

[0018] According to the sixth embodiment of the invention, the distance traveled for cleaning can be reduced compared to the case where the cleaning member is formed in an elongated rectangular shape and positioned diagonally across the surface of the sensor.

[0019] According to the seventh aspect of the invention, the moving mechanism reduces the distance required for cleaning while scattering foreign matter remaining on the sensor surface outwards in the short-side direction of the sensor surface, compared to the case where the moving mechanism only moves the cleaning member in the wiping direction to a position within (L / 2) × tanθ from the short side, where the intersection point of the intermediate portion of the inclined portion and the long side of the sensor surface intersects when the inclined portion of the cleaning member reaches the short side of the sensor surface.

[0020] According to the eighth aspect of the invention, compared to an image forming apparatus equipped with a sensor cleaning device in which the cleaning member moves foreign matter only in the wiping direction to clean the surface of the sensor, it is possible to suppress the occurrence of image quality defects due to toner density detection failures. [Brief explanation of the drawing]

[0021] [Figure 1] This is a schematic side view showing the configuration of the image forming apparatus according to this embodiment. [Figure 2]It is a schematic perspective view showing a cover body to which a conveyance unit constituting an image forming apparatus according to the present embodiment is attached and a main body frame. [Figure 3] It is a schematic perspective view showing the configuration of a sensor unit according to the present embodiment. [Figure 4] It is a schematic perspective view showing the configuration of a sensor cleaning device according to the first embodiment. [Figure 5] It is a schematic plan view showing a cleaning member of the sensor cleaning device according to the first embodiment. [Figure 6] It is an explanatory view showing a cleaning process by the cleaning member of the sensor cleaning device according to the first embodiment. [Figure 7] It is a schematic plan view showing a cleaning member of the sensor cleaning device according to the second embodiment. [[ID=十六]] [[ID=十七]] [Figure 8] It is an explanatory view showing a cleaning process by the cleaning member of the sensor cleaning device according to the second embodiment. [Figure 9] It is a schematic plan view showing a cleaning member of the sensor cleaning device according to the first modification of the second embodiment. [Figure 10] It is a schematic plan view showing a cleaning member of the sensor cleaning device according to the second modification of the second embodiment. [Figure 11] It is a schematic plan view showing a cleaning member of the sensor cleaning device according to the comparative example.

Mode for Carrying Out the Invention

[0022] Hereinafter, embodiments of the present invention will be described in detail based on the drawings. In each figure, for those arranged for each color of yellow (Y), magenta (M), cyan (C), and black (K), there are some to which the English letters "Y", "M", "C", and "K" are attached after the reference numeral.

[0023] First, an overview of the image forming apparatus 10 according to this embodiment will be described. As shown in Figures 1 and 2, the image forming apparatus 10 has a main frame 12 that detachably houses a photoreceptor 20 and a developing unit 16, and a cover body 14 that opens and closes the photoreceptor 20 and the developing unit 16. A transport unit 18 equipped with a transport belt 34 capable of picking up and transporting recording paper P is detachably attached to the cover body 14.

[0024] The developing unit 16 includes a charging roller 22 that uniformly charges the surface (outer surface) of the roll-shaped photoreceptor 20, an optical box 24 that irradiates the photoreceptor 20 with image light based on image data to form a latent image due to the difference in electrostatic potential, a developing roller 26 that selectively transfers toner to the latent image for visualization, and a cleaning member 28 that slides against the photoreceptor 20 after the toner image has been transferred to remove any remaining toner from the photoreceptor 20.

[0025] The photoreceptor 20 has a photoreceptor layer on its surface. After its surface is uniformly charged by the charging roller 22, its surface is exposed by laser light (image light) irradiated from the optical box 24. An electrostatic latent image (image) is formed as the potential of the exposed area attenuates. The charging roller 22 is in contact with the photoreceptor 20, and a voltage is applied between them. A discharge occurs in the minute gap near the contact point, causing the surface of the photoreceptor 20 to be charged almost uniformly.

[0026] The optical box 24 is configured to scan the surface of the photoreceptor 20 with a flashing laser beam, thereby forming an electrostatic latent image on the surface of the photoreceptor 20 based on the image data. The optical box 24 could be composed of an array of light-emitting elements such as LEDs, which are flashed based on the image data.

[0027] The developing roller 26 is positioned in close proximity to and opposite the photoreceptor 20, and a developing bias voltage is applied between the developing roller 26 and the photoreceptor 20. As a result, a developing bias electric field is formed between the developing roller 26 and the photoreceptor 20, causing the charged toner to transfer to the exposed portion on the photoreceptor 20 and form a visible image.

[0028] On the other hand, the transport unit 18 comprises a frame 51 with a roughly U-shaped cross-section and a roughly flat housing 50 that holds the frame 51. A drive roller 30 is rotatably supported at the upper end of the frame 51, and a driven roller 32 is rotatably supported at the lower end. A transport belt 34 capable of electrostatically adsorbing recording paper P is wound around and stretched over the drive roller 30 and the driven roller 32.

[0029] Furthermore, on the inner surface of the conveyor belt 34, transfer rollers 36 are arranged at predetermined intervals for each color between the drive roller 30 and the driven roller 32, and each transfer roller 36 is also rotatably supported by the housing 50.

[0030] Each transfer roller 36 is positioned to face the photoreceptor 20 across the transport belt 34 when the cover body 14 is closed (when the cover body 14 is rotated toward the main frame 12 to block the photoreceptor 20, etc.), and forms a transfer electric field between itself and the photoreceptor 20, thereby transferring the toner image (unfixed image) on the surface of the photoreceptor 20 onto the recording paper P that is attracted to and transported by the transport belt 34.

[0031] Here, the developing unit 16 is arranged vertically in the order of yellow (Y), magenta (M), cyan (C), and black (K) from bottom to top, for example, to enable full-color printing. A fixing device 38 is provided downstream of these developing units 16Y to 16K in the direction of transporting the recording paper P (upper part of the main frame 12).

[0032] The fixing device 38 includes a heating roller 40 and a pressure roller 42 whose circumferential surfaces face each other and are pressed (nipped) at a predetermined pressure. The heating roller 40 and the pressure roller 42 heat and pressurize the unfixed toner image transferred onto the recording paper P, thereby fixing the toner image to the recording paper P.

[0033] The recording paper P, which has been heated and pressurized by the fixing device 38 (heating roller 40 and pressure roller 42) to fix the toner image, is discharged onto the output tray 44. After the transfer of the toner image to the recording paper P is complete, the surface of the photoreceptor 20 is cleaned by the cleaning member 28 to prepare it for the next image-making process.

[0034] Furthermore, a removable paper feed cassette 46 is provided at the bottom of the main frame 12. This paper feed cassette 46 can be pulled out in the opposite direction to the direction in which the recording paper P is fed, allowing for the feeding of recording paper P as needed.

[0035] Furthermore, a pair of paper feed rollers 48 is provided near the leading edge of the paper feed cassette 46, which feeds out one sheet of recording paper P at a time from inside the paper feed cassette 46. The recording paper P fed out by the pair of paper feed rollers 48 is then fed by a pair of registration rollers 49 to the suction transport surface of the transport belt 34 at a predetermined timing, and transported to the transfer position of the toner image of each color.

[0036] <First Embodiment> Next, in the image forming apparatus 10 with the configuration described above, the sensor cleaning device 54 and the cleaning member 70 provided in the sensor cleaning device 54 according to the first embodiment will be described.

[0037] As shown in Figure 2, a canopy portion 50A extends from the upper end of the housing 50, allowing it to face the drive roller 30. This canopy portion 50A is provided with a sensor unit 52 that faces the conveyor belt 34 and is equipped with a pair of left and right density sensors 60 (see Figures 1 and 3), which are an example of sensors for detecting the density of the conveyor belt 34 or a test toner image (toner density detection pattern) transferred and formed on the conveyor belt 34.

[0038] As shown in Figures 3 and 4, the body of each density sensor 60 is formed in the shape of a rectangular box. The detection surface 62 (see Figure 5), which is an example of a surface facing the conveyor belt 34, has a long side portion 62L along the longitudinal direction and a short side portion 62S along the short direction intersecting the longitudinal direction. The density sensor 60 irradiates light from its detection surface 62 onto the toner image on the conveyor belt 34 at a predetermined angle, and receives the reflected light from the toner image on its detection surface 62. The received reflected light is converted into an electrical signal and transmitted to a detection device (not shown) to detect the toner density.

[0039] Furthermore, the sensor unit 52 has a sensor cleaning device 54 for cleaning the detection surface 62 of the concentration sensor 60. The sensor cleaning device 54 is positioned on the detection surface 62 side of the concentration sensor 60 and includes a sliding member 56 that moves (slides) in the longitudinal direction of the detection surface 62, and a moving mechanism 58 that moves the sliding member 56 in one direction in the longitudinal direction (hereinafter referred to as the "wiping direction") and in the opposite direction to the wiping direction (the other side in the longitudinal direction).

[0040] As shown in Figure 4, the moving mechanism 58 has a solenoid 64, the plunger 64A of the solenoid 64 is rotatably attached to one longitudinal end of the link member 66. The link member 66 is rotatably supported at its longitudinal center, and its other longitudinal end is rotatably attached to the back surface of the slide member 56 (the surface facing the detection surface 62 of the concentration sensor 60).

[0041] The solenoid 64 is configured to extend the plunger 64A when energized, causing the link member 66 to rotate around its longitudinal center and the slide member 56 to move in the wiping direction. The solenoid 64 is also configured to retract the plunger 64A when the energization is released, causing the link member 66 to rotate in the opposite direction around its longitudinal center and the slide member 56 to move in the opposite direction to the wiping direction.

[0042] Furthermore, the slide member 56 has a rectangular opening 56A that is the same size as, or slightly larger than, the detection surface 62 of the concentration sensor 60. Under normal circumstances, the detection surface 62 of the concentration sensor 60 faces the opening 56A. In other words, under normal circumstances, light is emitted from and received from the detection surface 62 of the concentration sensor 60 through the opening 56A.

[0043] Furthermore, a cleaning member 70 is attached to the back surface of the slide member 56, and on the upstream side in the wiping direction from the opening 56A. This cleaning member 70 moves along the longitudinal direction of the detection surface 62 of the concentration sensor 60, wiping and cleaning the entire detection surface 62 of the concentration sensor 60. It also has an inclined portion 72 positioned diagonally with respect to the wiping direction on the downstream side in the wiping direction, such that its upstream end in the wiping direction is located outside the detection surface 62 of the concentration sensor 60 in the short direction.

[0044] To explain in more detail, as shown in Figure 5, the cleaning member 70 according to the first embodiment is formed in an elongated rectangular shape with the longitudinal direction being along the inclined portion 72. In other words, this cleaning member 70 (the inclined portion 72, more specifically the portion that wipes the detection surface 62 of the concentration sensor 60) is formed asymmetrically with respect to the center line C along the longitudinal direction of the detection surface 62 of the concentration sensor 60, and is formed to a length that crosses the detection surface 62 of the concentration sensor 60. Here, "elongated" means that the ratio of the length of the longitudinal direction to the length of the short direction intersecting the longitudinal direction is, for example, 6 to 12:1, preferably about 8 to 10:1.

[0045] The moving mechanism 58 moves the cleaning member 70 in the wiping direction until at least the inclined portion 72 of the cleaning member 70 reaches the other corner 62B beyond one corner 62A on the downstream side of the detection surface 62 of the concentration sensor 60 in the wiping direction, and more preferably moves it to a position at least a distance Y1 away from the short side portion 62Sd described later.

[0046] In other words, when the length of the short side portion 62Sd on the downstream side of the detection surface 62 of the concentration sensor 60 is L, and the angle of the inclined portion 72 with respect to the short side portion 62Sd is θ, the moving mechanism 58 moves the cleaning member 70 in the wiping direction until, when the inclined portion 72 of the cleaning member 70 reaches the short side portion 62Sd (corner portion 62A), the intersection point X1 where the intermediate portion of the inclined portion 72 intersects with one of the long sides 62L of the detection surface 62 of the concentration sensor 60 is at least a distance Y1 = L × tanθ from the short side portion 62Sd.

[0047] Examples of cleaning members 70 include conductive nylon (registered trademark). Since toner is usually negatively polarized, it is preferable that the cleaning member 70 be made of a material such that the detection surface 62 of the concentration sensor 60 becomes negatively polarized due to frictional charging caused by wiping (sliding contact) with the detection surface 62.

[0048] The cleaning member 70 of the sensor cleaning device 54 according to the first embodiment, which has the configuration described above, will now be described in terms of its operation.

[0049] First, let's describe the comparative example shown in Figure 11. As shown in Figure 11(A), the cleaning member 68 in the comparative example is formed in a roughly square shape that is larger than the detection surface 62 of the concentration sensor 60. Therefore, as shown in Figures 11(B) and 11(C), when the cleaning member 68 is moved in the wiping direction and the detection surface 62 of the concentration sensor 60 is wiped with the cleaning member 68, foreign matter such as paper dust and toner (hereinafter referred to as "residual toner") T, which are examples of foreign matter adhering to the detection surface 62, is moved only to the downstream side of the detection surface 62 of the concentration sensor 60 in the wiping direction as the cleaning member 68 moves.

[0050] However, in the case of such a cleaning member 68, some of the residual toner T adheres to the downstream end of the cleaning member 68 in the wiping direction. As shown in Figure 11(D), when the cleaning member 68 is moved back in the opposite direction to the wiping direction, at least some of the residual toner T that was attached to the downstream end in the wiping direction is stretched and, as it passes through the detection surface 62 of the density sensor 60 and returns to its original position, it re-adheres to the detection surface 62.

[0051] In contrast, the cleaning member 70 according to the first embodiment, as shown in Figure 5, has an inclined portion 72 that is formed asymmetrically with respect to the center line C along the longitudinal direction of the detection surface 62 of the concentration sensor 60, and is positioned diagonally with respect to the wiping direction such that when it moves in the wiping direction and wipes and cleans the entire detection surface 62, the upstream end in the wiping direction is located outside the detection surface 62 in the short direction.

[0052] In other words, the cleaning member 70 is formed in an elongated rectangular shape with its longitudinal direction aligned with the inclined portion 72. The moving mechanism 58 moves the cleaning member 70 in the wiping direction until at least the inclined portion 72 of the cleaning member 70 has passed one corner 62A on the downstream side of the detection surface 62 of the concentration sensor 60 in the wiping direction and reached the other corner 62B, and more preferably to a position at least Y1 away from the short side portion 62Sd.

[0053] Therefore, as shown in Figure 6(A), when the cleaning member 70 is moved in the wiping direction and the detection surface 62 of the concentration sensor 60 is wiped with the cleaning member 70, as shown in Figures 6(B) and 6(C), the residual toner T adhering to the detection surface 62 is moved (scattered) along the inclined portion 72 of the cleaning member 70 as the cleaning member 70 moves, to the upstream side of the wiping direction of the detection surface 62 of the concentration sensor 60 and to the outside in the short direction of the detection surface 62.

[0054] Therefore, as shown in Figure 6(C), residual toner T is less likely to adhere to at least the downstream end in the wiping direction of the inclined portion 72 of the cleaning member 70 after wiping the detection surface 62 of the concentration sensor 60. Thus, as shown in Figure 6(D), even if the cleaning member 70 is moved back in the opposite direction to the wiping direction, the occurrence of a problem in which some of the residual toner T re-adheres to the detection surface 62 of the concentration sensor 60 when it passes through the detection surface 62 and returns to its original position is suppressed.

[0055] In other words, with the cleaning member 70 according to this first embodiment, compared to the case where the cleaning member 68 according to the comparative example moves the residual toner T only in the wiping direction to clean the detection surface 62 of the density sensor 60, the cleaning member 70 suppresses the re-adhesion of residual toner T to the detection surface 62 of the density sensor 60 when it passes through the detection surface 62 of the density sensor 60 and returns to its original position (return movement).

[0056] Furthermore, since the cleaning member 70 is formed in an elongated rectangular shape with its longitudinal direction aligned with the inclined portion 72, it is smaller (its area is reduced) compared to, for example, the cleaning member 68 in the comparative example. Consequently, the cost of the cleaning member 70 is reduced, and the contact load of the cleaning member 70 on the sensing surface 62 is also reduced. Therefore, a low-output solenoid 64 is sufficient, and the cost of the solenoid 64 is also reduced.

[0057] Furthermore, as described above, the moving mechanism 58 moves the cleaning member 70 in the wiping direction until at least the inclined portion 72 of the cleaning member 70 has passed one corner 62A on the downstream side of the detection surface 62 of the concentration sensor 60 in the wiping direction and reached the other corner 62B. Therefore, compared to the case where the moving mechanism 58 only moves the cleaning member 70 so that its inclined portion 72 reaches one corner 62A on the downstream side of the detection surface 62 of the concentration sensor 60 in the wiping direction, the amount of residual toner T remaining attached to the detection surface 62 of the concentration sensor 60 is suppressed.

[0058] As described above, it is preferable that the moving mechanism 58 moves the cleaning member 70 in the wiping direction until, when the inclined portion 72 of the cleaning member 70 reaches the short side portion 62Sd (corner portion 62A), the intersection point X1 where the intermediate portion of the inclined portion 72 intersects with one of the long sides 62L of the detection surface 62 of the concentration sensor 60 is at least a distance Y1 = L × tanθ from the short side portion 62Sd.

[0059] According to this, compared to the case where the moving mechanism 58 only moves the cleaning member 70 (intersection X1) in the wiping direction to a position within L × tanθ in distance from the short side portion 62Sd, this reduces the contact load of the cleaning member 70 on the detection surface 62 of the concentration sensor 60, while reliably scattering the residual toner T remaining on the detection surface 62 of the concentration sensor 60 to the outside in the short direction of the detection surface 62 of the concentration sensor 60 (see Figure 5).

[0060] Furthermore, with an image forming apparatus 10 equipped with a sensor cleaning device 54 having such a cleaning member 70, the occurrence of image quality defects due to toner density detection failures is suppressed compared to an image forming apparatus equipped with a sensor cleaning device having a cleaning member 68 according to the comparative example. In other words, the occurrence of malfunctions such as false detection and deviations in density sensitivity caused by contamination of the detection surface 62 of the density sensor 60 is suppressed.

[0061] <Second Embodiment> Next, the cleaning member 80 of the sensor cleaning device 54 according to the second embodiment will be described. Note that parts equivalent to those in the first embodiment are denoted by the same reference numerals, and detailed descriptions will be omitted as appropriate.

[0062] The cleaning member 80 according to the second embodiment cleans the detection surface 62 of the concentration sensor 60 by wiping the entire detection surface 62 of the concentration sensor 60 while moving in the longitudinal direction of the detection surface 62 of the concentration sensor 60, and has a plurality of (for example, two) inclined portions 82, 84 arranged diagonally with respect to the wiping direction on the downstream side of the wiping direction, such that the upstream end in the wiping direction is located outside the detection surface 62 of the concentration sensor 60 in the short direction.

[0063] To explain in more detail, as shown in Figure 7, in the cleaning member 80 according to the second embodiment, each inclined portion 82, 84 is formed to flare outwards from the downstream side to the upstream side in the wiping direction of the detection surface 62 of the concentration sensor 60, and the illustrated portion is formed in a roughly isosceles triangular shape. In other words, this cleaning member 80 is formed symmetrically (line symmetrically) with respect to the center line C along the longitudinal direction of the detection surface 62 of the concentration sensor 60, and each inclined portion 82, 84 is formed to have a length that crosses the detection surface 62 of the concentration sensor 60.

[0064] It should be noted that the term "symmetry (line symmetry)" used here includes not only exact symmetry (line symmetry) but also approximate symmetry (approximate line symmetry) that is close to exact symmetry (line symmetry). For example, in each inclined section 82, 84, the difference in length of one relative to the other is within ±5%, and the difference in inclination angle of the other relative to the other is within ±2 to 3 degrees, which are also included in the definition of "symmetry (line symmetry)" used here.

[0065] The moving mechanism 58 moves the cleaning member 80 in the wiping direction until at least each inclined portion 82, 84 of the cleaning member 80 reaches the corner portions 62A, 62B on the downstream side of the detection surface 62 of the concentration sensor 60 in the wiping direction, and more preferably moves it to a position at least a distance Y2 away from the short side portion 62Sd.

[0066] In other words, when L is the length of the short side portion 62Sd on the downstream side of the detection surface 62 of the concentration sensor 60 in the wiping direction, and θ is the angle of each inclined portion 82, 84 with respect to the short side portion 62Sd, the moving mechanism 58 moves the cleaning member 80 in the wiping direction until the intersection point X2 (shown only on the inclined portion 82 side, as it is in the same position in the wiping direction) where the intermediate portion of each inclined portion 82, 84 and the long side portion 62L of the detection surface 62 of the concentration sensor 60 intersect is at least a distance Y2 = (L / 2) × tanθ from the short side portion 62Sd.

[0067] The cleaning member 80 of the sensor cleaning device 54 according to the second embodiment, which has the configuration described above, will now be described in terms of its operation. Note that the operation common to the first embodiment will be omitted from the explanation as appropriate.

[0068] As shown in Figure 7, the cleaning member 80 according to the second embodiment is formed symmetrically (line symmetrically) with respect to the center line C along the longitudinal direction of the detection surface 62 of the concentration sensor 60, and has a plurality (2) of inclined portions 82, 84 that are positioned diagonally with respect to the wiping direction so that when it moves in the wiping direction and wipes and cleans the entire detection surface 62, the upstream end in the wiping direction is located outside the detection surface 62 in the short direction.

[0069] In other words, the cleaning member 80 is formed in a roughly isosceles triangular shape, with each inclined portion 82, 84 flaring outwards from the downstream side to the upstream side in the wiping direction of the concentration sensor 60. The moving mechanism 58 moves the cleaning member 80 in the wiping direction until at least each inclined portion 82, 84 of the cleaning member 80 reaches the corners 62A, 62B on the downstream side in the wiping direction of the detection surface 62 of the concentration sensor 60, and more preferably until it is at a distance Y2 from the short side 62Sd.

[0070] Therefore, as shown in Figure 8(A), when the cleaning member 80 is moved in the wiping direction and the detection surface 62 of the concentration sensor 60 is wiped with the cleaning member 80 as shown in Figures 8(B) and 8(C), the residual toner T adhering to the detection surface 62 is moved (scattered) along the inclined portions 82 and 84 of the cleaning member 80 as the cleaning member 80 moves, on the upstream side of the wiping direction of the detection surface 62 of the concentration sensor 60 and outward in the short direction of the detection surface 62.

[0071] Therefore, as shown in Figure 8(C), residual toner T is less likely to adhere to at least the downstream end in the wiping direction of each inclined portion 82, 84 of the cleaning member 80 after wiping the detection surface 62 of the concentration sensor 60. Thus, as shown in Figure 8(D), even if the cleaning member 80 is moved back in the opposite direction to the wiping direction, the occurrence of a problem in which some of the residual toner T re-adheres to the detection surface 62 of the concentration sensor 60 when it passes through the detection surface 62 and returns to its original position is suppressed.

[0072] In other words, with the cleaning member 80 according to this second embodiment, compared to the case where the cleaning member 68 according to the comparative example moves the residual toner T only in the wiping direction to clean the detection surface 62 of the density sensor 60, the cleaning member 80 is less likely to reattach the residual toner T to the detection surface 62 of the density sensor 60 when it passes through the detection surface 62 of the density sensor 60 and returns to its original position (return movement).

[0073] Furthermore, since the inclined portions 82 and 84 of the cleaning member 80 are formed to flare outwards from each other from the downstream side to the upstream side in the wiping direction, the travel distance required for cleaning is reduced compared to, for example, the cleaning member 70 according to the first embodiment (distance Y2 < distance Y1). As a result, the sensor cleaning device 54 can be miniaturized, and the degree of freedom in the layout of the sensor cleaning device 54 is improved.

[0074] Furthermore, as described above, the moving mechanism 58 moves the cleaning member 80 in the wiping direction until at least each of the inclined portions 82 and 84 of the cleaning member 80 reaches the corners 62A and 62B on the downstream side of the detection surface 62 of the concentration sensor 60 in the wiping direction. Therefore, compared to the case where the moving mechanism 58 only moves the cleaning member 80 to a position where each of the inclined portions 82 and 84 does not reach the corners 62A and 62B on the downstream side of the detection surface 62 of the concentration sensor 60 in the wiping direction, the amount of residual toner T remaining attached to the detection surface 62 of the concentration sensor 60 is suppressed.

[0075] As described above, it is preferable that the moving mechanism 58 moves the cleaning member 80 in the wiping direction until, when each inclined portion 82, 84 (vertex portion) of the cleaning member 80 reaches the short side portion 62Sd, the intersection point X2 where the intermediate portion of each inclined portion 82, 84 intersects with the long side portion 62L of the concentration sensor 60 is at least a distance Y2 = (L / 2) × tanθ from the short side portion 62Sd.

[0076] According to this, compared to the case where the moving mechanism 58 only moves the cleaning member 80 (intersection X2) in the wiping direction to a position within (L / 2) × tanθ of the short side portion 62Sd, the distance required for cleaning is reduced, while reliably scattering the residual toner T remaining on the detection surface 62 of the concentration sensor 60 to the outside in the short direction of the detection surface 62 of the concentration sensor 60 (see Figure 7).

[0077] Moreover, since the cleaning member 80 has inclined portions 82 and 84 that are formed to flare outwards from each other from the downstream side to the upstream side in the wiping direction, and are symmetrical with respect to the center line C, it scatters the residual toner T to the outside in the short direction of the detection surface 62 of the density sensor 60 in approximately the same amount compared to the cleaning member 70 according to the first embodiment (see Figure 8(D)).

[0078] (First variation) In this second embodiment, the cleaning member 81 may have the shape shown in Figure 9. Specifically, this cleaning member 81 is formed in a roughly ">" shape with the downstream end in the wiping direction as the apex (the central part of the short side on the upstream side of the cleaning member 80 in the wiping direction is cut out in a roughly isosceles triangle shape), and has a plurality (2) of inclined portions 83 and 85 that are flared outwards from each other from the downstream side to the upstream side in the wiping direction of the detection surface 62 of the concentration sensor 60.

[0079] With the cleaning member 81 having this shape, the same effects and functions as the cleaning member 80 can be obtained, as well as the same effects and functions as the cleaning member 70. That is, since the cleaning member 81 has multiple inclined portions 83 and 85 that are formed to flare outwards from the downstream side to the upstream side in the wiping direction, the travel distance required for cleaning is reduced compared to, for example, the cleaning member 70 according to the first embodiment. As a result, the sensor cleaning device 54 can be made smaller, and the freedom of layout in the sensor cleaning device 54 is improved.

[0080] Furthermore, since the cleaning member 81 is formed in a shape in which the central part of the shorter side on the upstream side of the cleaning member 80 in the wiping direction is cut out in a roughly isosceles triangle shape, it is smaller (the area is reduced) compared to, for example, the cleaning member 68 in the comparative example. Consequently, the cost of the cleaning member 81 is reduced, and the contact load of the cleaning member 81 on the sensing surface 62 is also reduced. Therefore, a low-output solenoid 64 is sufficient, and the cost of the solenoid 64 is also reduced.

[0081] (Second variation) Furthermore, in this second embodiment, the cleaning member 74 may have the shape shown in Figure 10. That is, this cleaning member 74 is formed in a triangular shape with three sides of different lengths, and has a plurality (2) of inclined portions 76, 78 that are flared outwards from each other, extending from the downstream side to the upstream side in the wiping direction of the detection surface 62 of the concentration sensor 60. In other words, this cleaning member 74 is formed asymmetrically with respect to the center line C along the longitudinal direction of the detection surface 62 of the concentration sensor 60, and each of the inclined portions 76, 78 is formed to have a length that crosses the detection surface 62 of the concentration sensor 60.

[0082] Then, when each inclined portion 76, 78 (vertex portion) of the cleaning member 74 reaches the short side portion 62Sd, the moving mechanism 58, when the length of a portion of the short side portion 62Sd from the vertex portion to the corner portion 62B is L1, the length of the remaining portion of the short side portion 62Sd from the vertex portion to the corner portion 62A is L2, the angle of the inclined portion 76 with respect to the short side portion 62Sd is θ1, and the angle of the inclined portion 78 with respect to the short side portion 62Sd is θ2, the intermediate portion of the inclined portion 76 The cleaning member 74 is moved in the wiping direction until the intersection point X3 where the detection surface 62L of the concentration sensor 60 intersects with one of the longer sides 62L is at least a distance Y3 = L1 × tanθ1 from the shorter side 62Sd, or until the intersection point X4 where the intermediate part of the inclined portion 78 intersects with the other longer side 62L of the detection surface 62 of the concentration sensor 60 intersects with the cleaning member 74 is at least a distance Y4 = L2 × tanθ2 from the shorter side 62Sd.

[0083] In other words, the cleaning member 74 is moved in the wiping direction by a distance greater than or equal to the longer of the two distances, Y3 and Y4. In the case of the cleaning member 74 shown in Figure 10, since distance Y3 > distance Y4, the cleaning member 74 is moved in the wiping direction to a position at least Y3 away from the short side portion 62Sd. This ensures that the residual toner T remaining on the detection surface 62 of the density sensor 60 is scattered outwards in the short direction of the detection surface 62 of the density sensor 60 (see Figure 10).

[0084] The sensor cleaning device 54 according to this embodiment has been described above based on the drawings. However, the sensor cleaning device 54 according to this embodiment is not limited to the illustrated version, and can be modified as appropriate without departing from the spirit of the present invention. For example, the shape of the cleaning members according to this embodiment is not limited to the shapes of the illustrated cleaning members 70, 74, 80, and 81.

[0085] Furthermore, the moving mechanism 58 is not limited to one that includes the solenoid 64 shown in the figure. The moving mechanism 58 may be configured such that, for example, the sliding member 56 moves (slides) in conjunction with the opening and closing of the cover body 14. In such a configuration, the solenoid 64 does not need to be provided, thus reducing the manufacturing cost of the sensor cleaning device 54.

[0086] Furthermore, the density sensor 60 may be positioned facing the surface of the photoreceptor 20, rather than facing the conveyor belt 34. Also, the detection surface 62 of the density sensor 60 only needs to have corners 62A and 62B formed on the downstream side in the wiping direction, and does not need to have corners formed on the upstream side in the wiping direction (the upstream side in the wiping direction may be formed in a substantially arc shape, for example). [Explanation of Symbols]

[0087] 10 Image forming apparatus 54 Sensor cleaning device 58 Moving mechanism 60. Concentration Sensor (An example of a sensor) 62. Detection surface (an example of a surface) 62A Corner 62B Corner 62L (long side) 62S Short side 70 Cleaning parts 72 Slope 74 Cleaning parts 76 Slope 78 Slope 80 Cleaning parts 82 Slope 84 Slope

Claims

1. A cleaning member has an inclined portion that is positioned diagonally with respect to the wiping direction such that the upstream end of the wiping direction is located outside the short direction of the sensor surface, and the surface of the sensor, which has a long side portion along the longitudinal direction and a short side portion along the short direction intersecting the longitudinal direction, is moved along the longitudinal direction of the sensor surface to wipe and clean the entire surface of the sensor, and the upstream end of the wiping direction is located outside the short direction of the sensor surface, A moving mechanism for moving the cleaning member in the direction opposite to the wiping direction, Equipped with, The cleaning member is formed asymmetrically with respect to the center line along the longitudinal direction of the surface of the sensor, The moving mechanism is a sensor cleaning device that moves the cleaning member in the wiping direction until at least the inclined portion of the cleaning member reaches the other corner on the downstream side of the surface of the sensor in the wiping direction.

2. The sensor cleaning device according to claim 1, wherein the cleaning member is formed in a rectangular shape with the direction along the inclined portion as the longitudinal direction.

3. When L is the length of the short side of the sensor surface on the downstream side in the wiping direction, and θ is the angle of the inclined portion with respect to the short side, The sensor cleaning device according to claim 2, wherein the moving mechanism moves the cleaning member in the wiping direction to a position where the intersection point where the intermediate portion of the inclined portion of the cleaning member and the long side portion of the surface of the sensor intersect is at least L × tanθ away from the short side portion when the inclined portion of the cleaning member reaches the short side portion.

4. A cleaning member having an inclined portion that is positioned diagonally with respect to the wiping direction such that the upstream end of the wiping direction is located outside the short direction of the sensor surface, and the surface of the sensor having a long side portion along the longitudinal direction and a short side portion along the short direction intersecting the longitudinal direction, moves along the longitudinal direction of the sensor surface to wipe and clean the entire surface of the sensor, and the upstream end of the wiping direction is located outside the short direction of the sensor surface, A moving mechanism for moving the cleaning member in the direction opposite to the wiping direction, Equipped with, The cleaning member is formed symmetrically with respect to the center line along the longitudinal direction of the surface of the sensor and has a plurality of inclined portions. The moving mechanism is a sensor cleaning device that moves the cleaning member in the wiping direction until at least a plurality of the inclined portions of the cleaning member each reach a corner on the downstream side of the surface of the sensor in the wiping direction.

5. The sensor cleaning device according to claim 4, wherein the cleaning member has a plurality of inclined portions that are arranged to flare outwards from each other from the downstream side to the upstream side in the wiping direction of the surface of the sensor.

6. When L is the length of the short side of the sensor surface on the downstream side in the wiping direction, and θ is the angle of the inclined portion with respect to the short side, The sensor cleaning device according to claim 5, wherein the moving mechanism moves the cleaning member in the wiping direction to a position where the intersection point where the intermediate portion of the inclined portion of the cleaning member and the long side portion of the surface of the sensor intersect is at least (L / 2) × tanθ away from the short side portion when the inclined portion of the cleaning member reaches the short side portion.

7. A sensor for detecting the density of a toner density detection pattern, A sensor cleaning device according to any one of claims 1 to 6, which cleans the surface of the sensor by wiping it; An image forming apparatus equipped with [a specific feature].

Images