JP4780708B2 - Cleaning mechanism and image forming apparatus provided with the same - Google Patents

Description

  The present invention relates to a cleaning mechanism for removing foreign matters such as toner and dust adhering to the sensor surface of an optical density sensor, and an image forming apparatus including the same.

  In an image forming apparatus such as an electrophotographic copying machine or printer, the density of a toner image depends on image forming conditions (for example, charging bias, developing bias, transfer bias) in charging, developing, transferring, etc., and an environment such as temperature and humidity. Therefore, on the contrary, the density of the toner image is detected, and the image forming conditions for obtaining the toner image having a desired density are determined.

  For this purpose, it is necessary to detect the density of the toner image with high accuracy. For this detection, an optical density sensor is generally used (see, for example, Patent Documents 1 to 4). A toner image (patch) for density detection is formed on the surface of an image carrier such as a photosensitive drum or an intermediate transfer belt, the density of the toner image is detected by a density sensor, and the detection result is feed-packed to image forming conditions. I am doing so. The density sensor is arranged so that the sensor surface faces the surface of the image carrier, and the irradiation light from the light emitting unit and the reflected light from the toner image are transmitted through the sensor surface. For this reason, if the sensor surface is contaminated by foreign matter such as scattered toner, dust, or paper dust, the amount of light transmitted through the sensor surface changes, making it impossible to detect density with high accuracy.

  In order to prevent such a problem, a technique for cleaning the sensor surface by a cleaning mechanism is known. For example, a cleaning member (cleaning member) is disposed so as to be swingable or reciprocable, and the cleaning member is biased in one direction by a biasing member such as a spring, and is retracted from the sensor surface during normal image formation. Let me. In cleaning, the foreign matter adhering to the sensor surface is wiped off by rubbing against the urging force of the urging member or by rubbing the sensor surface with the cleaning member in accordance with the urging force. In some cases, the cleaning operation of the cleaning member is performed in conjunction with the opening / closing operation of the opening / closing cover.

JP 2000-330442 A JP 2001-201907 A JP-A-10-39716 JP 2000-39762 A

  By the way, in the cleaning member as described above, a fibrous wiping member (for example, an acrylic pile seal) having raised hairs in a portion that rubs the sensor surface may be used. The wiping member is rubbed while being pressed against the sensor surface to wipe off foreign matters such as scattered toner, dust, and paper dust adhering to the sensor surface.

  However, when the cleaning operation by the wiping member is a regular swinging motion or reciprocating motion, the trajectory of the raised hair on the sensor surface is always constant, and the foreign matter in the passing portion of the raised hair accumulates in the portion where the raised hair does not pass. There is a problem that so-called wiping unevenness occurs and the generated wiping unevenness cannot be eliminated. For this reason, it becomes impossible to detect the density with high accuracy by the density sensor.

  An object of the present invention is to provide a cleaning mechanism that can reliably remove foreign matter adhering to the sensor surface without causing wiping unevenness, and an image forming apparatus including the cleaning mechanism. .

  The invention according to claim 1 relates to a cleaning mechanism for wiping off foreign matter adhering to the sensor surface of an optical density sensor disposed opposite to the surface of a belt member that carries and conveys a toner image. A cleaning mechanism according to the present invention includes a cleaning member that wipes off foreign matter that is rubbed against the sensor surface and adheres to the sensor surface, and the cleaning member is placed on the sensor along a plane along the sensor surface. A guide member for reciprocally moving between a retracted position for exposing the surface and a cleaning position for rubbing the sensor surface; and an urging force for urging the cleaning member from the retracted position side toward the cleaning position side. The cleaning means according to the biasing force of the biasing means by the biasing means, the closed position that receives the cleaning member biased by the biasing means and places the cleaning member in the retracted position, and the opening operation from the closed position to the open position. The member is moved from the retracted position to the cleaning position, and the cleaning member is moved from the cleaning position to the retracted position against the biasing force of the biasing means by the closing operation from the open position to the closed position. An opening / closing member to be moved, and when the direction perpendicular to the reciprocating movement direction on the plane is a width direction, the cleaning member is interposed between the cleaning member and the guide member during the reciprocating movement. In addition to providing a margin part that allows deflection in the width direction, and provided with a vibration generating means for generating a vibration in the width direction by the margin part during the reciprocating movement with respect to the cleaning member. Yes.

  According to a second aspect of the present invention, in the cleaning mechanism according to the first aspect, the biasing means includes a plurality of biasing members engaged at different positions in the width direction of the cleaning member, The generating means is configured by different urging forces of the plurality of urging members with respect to the cleaning member.

According to a third aspect of the present invention, in the cleaning mechanism according to the first aspect, the vibration generating means is constituted by a concave guide provided on the guide portion side in one margin portion of the cleaning member in the width direction. ing,
It is characterized by that.

  According to a fourth aspect of the present invention, in the cleaning mechanism according to the second or third aspect, the cleaning member has a convex contact portion at a portion that contacts the opening / closing member.

  According to a fifth aspect of the present invention, in the cleaning mechanism according to the first aspect, the shake generating means is configured by an inclined engaging portion that is provided on the opening / closing member and contacts the cleaning member, and the inclined engaging portion is The contact position with the cleaning member changes between one end side in the width direction of the cleaning member and the other end side with the opening / closing operation of the opening / closing member. Yes.

  According to a sixth aspect of the present invention, in the cleaning mechanism according to the first aspect, the vibration generating means includes a concavo-convex portion provided on one of the cleaning member and the guide member in the margin portion, and the other. And an engaging portion that engages and disengages with the concavo-convex portion with the reciprocating movement of the cleaning member.

  A seventh aspect of the present invention is the cleaning mechanism according to any one of the first to sixth aspects, wherein the cleaning member wipes the foreign matter adhering to the sensor surface by rubbing the sensor surface. And a pressing portion for preventing the wiping member from being lifted and ensuring an intrusion amount when the sensor surface is rubbed by the wiping member.

  According to an eighth aspect of the present invention, in the cleaning mechanism according to any one of the first to seventh aspects, the cleaning member covers the sensor surface when the cleaning member is disposed at the cleaning position.

  The invention according to claim 9 is a belt member that carries and conveys a toner image, an image forming unit that forms a toner image on the belt member, and an optical type that detects the density of the toner image formed on the surface of the belt member. The present invention relates to an image forming apparatus provided with a density sensor and a cleaning mechanism for cleaning a sensor surface of the density sensor. The image forming apparatus according to the present invention is characterized in that the cleaning mechanism is the cleaning mechanism according to any one of claims 1 to 8.

  According to the invention of claim 1, the cleaning member urged by the urging means is guided by the guide member and moved from the retracted position to the cleaning position when the opening / closing member is opened from the closed position to the open position. Then, the sensor surface is rubbed and the foreign matter adhering to the sensor surface is wiped off. In addition, when the opening / closing member is closed from the open position to the closed position, it is guided by the guide member to move from the cleaning position to the retracted position and rubs the sensor surface to wipe off foreign matter adhering to the sensor surface. To do. That is, the cleaning member reciprocates between the retracted position and the cleaning position in conjunction with the opening / closing operation of the opening / closing member, and at this time, the sensor surface is rubbed and cleaned. Further, since an extra portion is provided between the cleaning member and the guide member, and the cleaning member uses the extra portion to cause the deflection in the width direction during the reciprocating movement of the cleaning member, the cleaning member serves as a sensor. Unlike the case where only the reciprocating movement is constant, the trajectory for rubbing the surface is a complex and irregular combination of the reciprocating movement and the fluctuation in the width direction. Thereby, wiping unevenness can be eliminated.

  According to the invention of claim 2, since the urging forces of the plurality of urging members with respect to the cleaning member are different, a force (moment) for rotating the urging member on the same plane acts on the cleaning member. The posture of the cleaning member during the reciprocating movement becomes unstable, and the locus of the cleaning member at the time of rubbing against the sensor surface is likely to change. Note that measures for changing the urging force of the urging members include changing the spring constant, changing the length, changing the mounting position of the plurality of urging members. That is, the moment acting on the cleaning member may not be balanced.

  According to the third aspect of the present invention, when the cleaning member reciprocates, if it moves following the concave guide, the widthwise deflection increases, and the locus of the cleaning member during rubbing changes greatly.

  According to the invention of claim 4, the cleaning member is urged by the urging member and comes into contact with the opening / closing member. However, since this contact is made by the convex contact portion, the posture of the cleaning member is unstable. It becomes easy to shake in the width direction.

  According to the invention of claim 5, the contact portion of the cleaning member with respect to the inclined engagement portion on the opening / closing member side is between the one end portion side and the other end portion side in the width direction by the opening / closing operation of the opening / closing member. Therefore, it is possible to generate a wobbling in the width direction of the cleaning member that is reciprocating.

  According to the invention of claim 6, when the cleaning member is guided by the guide member and reciprocates, the uneven portion formed on one of these and the engaging portion formed on the other are disengaged. Therefore, the cleaning member is shaken in the width direction as it is reciprocated.

  According to the seventh aspect of the invention, when the cleaning member is rubbed against the sensor surface, the pressing member can prevent the cleaning member from floating from the sensor surface and press the cleaning member against the sensor surface. The foreign matter adhering to can be reliably wiped off by the cleaning member.

  According to the invention of claim 8, when the opening / closing member is arranged at the open position, for example, the vicinity of the concentration sensor may be exposed, but the cleaning member arranged at the cleaning position covers the sensor surface, so that the sensor The surface is never exposed. Therefore, even when the opening / closing member is disposed at the open position, it is possible to prevent the sensor surface from being accidentally damaged or foreign matter from adhering to the sensor surface.

  According to the ninth aspect of the present invention, the cleaning mechanism can clean the sensor surface of the density sensor so that there is no wiping unevenness, so that the density sensor can detect the density with high accuracy. A high-quality image can be formed by appropriately setting image forming conditions based on the detection result.

  The belt member includes a photosensitive belt and an intermediate transfer belt. The density sensor and the cleaning mechanism for cleaning the sensor surface should be applied to both the photosensitive belt and the intermediate transfer belt. Can do.

  Hereinafter, the best embodiment of the present invention will be described in detail with reference to the drawings.

<Embodiment 1>
First, an outline of the configuration and operation of the image forming apparatus 10 according to the present invention will be described, and then the cleaning mechanism 50 according to the present invention will be described in detail. Examples of the image forming apparatus 10 include a copying machine, a printer, a facsimile, and a complex machine of these.

  1 and 2 show an image forming apparatus 10 according to the present invention. Among these, FIG. 1 is a view showing an overview of the image forming apparatus 10 as a whole, and is a perspective view seen obliquely from the upper front right. Here, in the following description, unless otherwise specified, the directions indicated by the arrows on the upper right in FIG. FIG. 2 is a diagram schematically showing a longitudinal section when the image forming apparatus 10 is viewed from the direction of the arrow X (front side) in FIG. In addition, this figure shows a state in which the intermediate transfer unit 20 is mounted at a predetermined position (transfer portion T) of the image forming apparatus main body M. The image forming apparatus 10 shown in these drawings is a four-color full-color image forming apparatus (printer) of an electrophotographic system and an intermediate transfer system, and the intermediate transfer unit 20 is configured to be detachable from the image forming apparatus main body M. Has been. Here, the image forming apparatus main body M refers to a portion obtained by removing the intermediate transfer unit 20 from the entire image forming apparatus 10.

  As shown in FIG. 2, in the image forming apparatus 10, a drum-shaped electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) 11 is disposed as an image carrier in the approximate center of the image forming apparatus main body M. . The photosensitive drum 11 is rotationally driven in the direction of arrow R11 by a driving means (not shown), and the surface (outer peripheral surface) thereof is uniformly charged to a predetermined polarity and potential by the charging roller 12. The surface of the photosensitive drum 11 after charging is subjected to exposure L based on image information by an exposure device 13 such as a laser scanner, and the charge of the exposed portion is removed to form an electrostatic latent image.

  The electrostatic latent image is developed by the developing device 14. The developing device 14 includes a rotatable rotary 14a and four developing devices mounted on the rotary 14a, that is, the first color yellow (Y), the second color magenta (M), and the third color cyan ( C), black (K) developing devices 14Y, 14M, 14C, and 14K for the fourth color. The developing device 14 is a developing unit used for developing an electrostatic latent image formed on the surface of the photosensitive drum 11, and in the example of FIG. 2, a yellow developing unit 14Y for the first color in the direction of the arrow R14 of the rotary 14a. By rotation, the photosensitive drum 11 is disposed at a development position facing the surface of the photosensitive drum 11. The yellow developing device 14Y disposed at the developing position attaches yellow toner to the electrostatic latent image on the surface of the photosensitive drum 11 and develops it as a yellow toner image.

  This yellow toner image is transferred to an intermediate transfer belt 15 as a belt member. The intermediate transfer belt 15 is formed in an endless shape (endless), and is stretched around four rollers, that is, a tension roller 16, a primary transfer roller 17, a guide roller 18, and a driving roller 19. In the present embodiment, the driving roller 19 is a secondary transfer counter roller that sandwiches the intermediate transfer belt 15 between a secondary transfer roller 22 described later. The intermediate transfer belt 15 is pressed against the photosensitive drum 11 by the primary transfer roller 17 from the back side thereof, whereby the intermediate transfer belt 15 is moved between the photosensitive drum 11 and the intermediate transfer belt 15 (the movement of the intermediate transfer belt 15). A strip-shaped primary transfer nip N1 that is long in the horizontal direction) is formed. The intermediate transfer belt 15 rotates (endlessly moves) in the direction of the arrow R15 as the driving roller 19 is driven and rotated in the direction of the arrow R19 by a driving unit (not shown). The yellow toner image formed on the surface of the photosensitive drum 11 is applied to the primary transfer roller 17 by applying a primary transfer bias to the surface of the intermediate transfer belt 15 in the primary transfer nip N1. Transferred and carried.

  The intermediate transfer belt 15, the tension roller 16, the primary transfer roller 17, the guide roller 18, the drive roller 19, and the like described above are incorporated in the intermediate transfer housing 39 to constitute the intermediate transfer unit 20 as a whole. The intermediate transfer unit 20 is detachably attached to the image forming apparatus main body M in units. A cleaning mechanism 50 to be described later is disposed so as to face the intermediate transfer belt 15 of the intermediate transfer unit 20 mounted on the image forming apparatus main body M.

  The photosensitive drum 11 after the primary transfer of the toner image is removed by the cleaning device 21 after the primary transfer residual toner, that is, the toner remaining on the surface of the photosensitive drum 11 without being transferred to the intermediate transfer belt 15 during the primary transfer. The second color magenta is used for image formation.

  The above-described image forming process, that is, a series of processes of charging, exposure, development, primary transfer, and cleaning is sequentially performed for the remaining three colors other than yellow, that is, magenta, cyan, and black. The toner images of four colors of yellow, magenta, cyan, and black are superposed on the surface of the toner.

  When the primary transfer of the four-color toner images to the surface of the intermediate transfer belt 15 is completed, these toner images are conveyed from a paper feed cassette 23 disposed in the lower part of the image forming apparatus main body M. Transferred to the material P. The sheet material P is stored in the paper feed cassette 23 and is fed one by one by a paper feed roller 24, a feed roller 25, and a retard roller 26, and further by a large-diameter roller 27, transport rollers 28, 29, and the like. Then, it is conveyed to the stopped registration roller pair 30 to correct the skew. Thereafter, the sheet material P is supplied to the secondary transfer nip N <b> 2 by the registration roller pair 30 rotating in synchronization with the four color toner images on the surface of the intermediate transfer belt 15. A secondary transfer bias is applied to the secondary transfer roller 22 with respect to the sheet material P thus supplied to the secondary transfer nip N2, whereby toner images of four colors are collectively transferred in a batch. The secondary transfer roller 22 is separated from the surface of the intermediate transfer belt 15 except during the secondary transfer of the toner image.

  The intermediate transfer belt 15 after the secondary transfer of the toner image is not transferred to the sheet material P, and the toner remaining on the surface (secondary transfer residual toner) is removed by the belt cleaner 31 to perform the primary transfer of the next toner image. And subjected to secondary transfer.

  On the other hand, the sheet material P after the secondary transfer of the toner image is conveyed to the fixing device 32 where it is heated and pressed by the fixing roller 33 and the pressure roller 34 to fix the toner image on the surface. The sheet material P after the toner image is fixed is discharged to a discharge tray 42 on the upper surface of the image forming apparatus main body M by transfer rollers 35 and 36, a switching flapper 38, a transfer roller pair 40, and a discharge roller pair 41. The four-color full-color image formation on one surface (front surface) of one sheet material P is thus completed.

  On the other hand, when image formation is performed on both surfaces (the front surface and the back surface) of the sheet material P, the sheet material P having the toner image fixed on the front surface has a trailing edge that passes through the transport rollers 35 and 36. The switching flapper 38 is switched, the transport roller pair 40 is reversed, and the transport rollers 36 and 37 are rotated to be guided to the refeed path 43 and reversed upside down. Then, the sheet is conveyed to the registration roller pair 30 by the re-feed roller pair 44 and the re-conveyance roller pair 45, and the toner image is secondarily transferred to the back surface and fixed as in the case of one side (front side). Thereafter, the paper is discharged to the paper discharge tray 42. Thus, the four-color full-color image formation on both sides of one sheet material P is completed.

  A manual paper feed roller 46 used for manual paper feeding is disposed above the large-diameter roller 27 on the right side of the image forming apparatus main body M. At the time of manual feeding, when the opening / closing cover (opening / closing member) 47 shown in FIG. 1 is opened so that the upper end side is pulled rightward with the lower end side fulcrum 47a (see FIGS. 4 and 5) as the center, the upper surface is manually inserted. The back surface of the sheet material P is guided as a paper feed tray. The opening / closing cover 47 is also opened / closed when the intermediate transfer unit 20 is attached to or detached from the image forming apparatus main body M, when a toner supply container 48 (see FIG. 2) described later is replaced, or when a jam (paper jam) is handled. The Further, as will be described later, the opening / closing cover 47 constitutes a part of the cleaning mechanism 50 according to the present invention, and the opening / closing operation of the opening / closing cover 47 (the opening operation in the direction of the arrow R47a shown in FIG. The cleaning member 52 performs a cleaning operation in conjunction with a closing operation in the direction of the arrow R47b shown in FIG. A toner supply container 48 is disposed above the intermediate transfer unit 20. The toner replenishing container 48 individually stores toner of each color to be replenished to the developing devices 14Y, 14M, 14C, and 14K of each color of the developing device 14. The toners of these colors are supplied to the developing devices 14Y, 14M, 14C, and 14K of the respective colors by a toner supply device 49 as necessary. In the image forming apparatus 10 described above, the photosensitive drum 11, the charging roller 12, the exposure device 13, the developing device 14, the intermediate transfer unit 20, the cleaning device 21, and the like constitute an image forming unit.

  This is the end of the description of the overall configuration and operation of the entire image forming apparatus 10.

  In the image forming apparatus 10 configured as described above, as shown in FIG. 2, an optical density sensor 51 is disposed below the tension roller 16 of the intermediate transfer unit 20 so as to face the surface of the intermediate transfer belt 15. Has been. A toner image (patch) for density detection is formed on the surface of the photosensitive drum 11 for each color of yellow, magenta, cyan, and black and transferred to the surface of the intermediate transfer belt 15. Then, the density of the toner image is detected by the density sensor 51, and the detection result is feed-packed to determine the developing bias and the transfer bias. Thereby, a high quality toner image is formed.

  By the way, when foreign matter such as scattered toner, dust or paper dust adheres to the surface (hereinafter referred to as “sensor surface S”) S of the density sensor 51, the irradiation light or reflected light transmitted through the sensor surface S changes. Accurate density detection cannot be performed. Therefore, in this embodiment, the cleaning mechanism 50 is provided to clean the sensor surface S of the concentration sensor 51.

  Next, with reference to FIG. 3, the concentration sensor 51 to be cleaned by the cleaning mechanism 50 according to the present invention will be described. FIG. 3 is a diagram for explaining how the density sensor 51 is attached to the attachment member 53.

  As shown in FIG. 3, the density sensor 51 has a box-shaped sensor body 54 and a plate-shaped sensor base 55 formed integrally. The sensor main body 54 has a flat sensor surface S on the upper surface, and a light emitting unit (not shown) for irradiating light toward the toner image on the surface of the intermediate transfer belt 15 and a toner image And a light receiving portion (not shown) for receiving the reflected light. Both irradiated light and reflected light pass through the sensor surface S described above. The sensor base 55 has four through holes 56, one at each of the four corners, and the lower two are engaged with the bosses 57 on the mounting member 53 side. The screw 58 is passed through the two, and the screw 58 is screwed into the screw hole 60 of the mounting member 53, thereby being fixed to the mounting member 53. Thus, as shown in FIGS. 4 and 5, the attachment member 53 to which the density sensor 51 is attached is screwed to the lower surface (back surface) of the attachment metal plate 61 of the image forming apparatus main body M from below. The mounting state of the density sensor 51 will be described in detail after the mounting sheet metal 61 is described.

  With reference to FIGS. 4-8, the attachment sheet metal 61 is demonstrated. Among these drawings, FIG. 4 is a front view for explaining a state in which the cleaning member 52 is disposed at the retracted position by the opening / closing cover 47 disposed at the closed position. FIG. 5 is a front view for explaining a state in which the cleaning member 52 is disposed at the cleaning position by the opening / closing cover 47 during the opening operation from the closed position toward the open position (not shown). FIG. 6 is a perspective view of the density sensor 51 as viewed from obliquely upward and rearward on the right side of the image forming apparatus main body M. FIG. 7 is a perspective view of the mounting sheet metal 61 as a single unit as viewed from the upper left obliquely upper side. FIG. 8 is a view seen from substantially the same direction as FIG. 7, and shows a state where the cleaning member 52 is attached to the attachment metal plate 61 and the opening / closing cover 47 is opened.

  As shown in FIG. 4, the attachment metal plate 61 is provided on the tension side 15a of the intermediate transfer belt 15 on the upstream side of the driving roller 19 along the rotation direction of the intermediate transfer belt 15 (arrow R15 direction) and the tension roller. 16 is disposed substantially in parallel with a narrow gap therebetween. The attachment metal plate 61 is disposed so as to be substantially parallel to the intermediate transfer belt 15 and to be higher on the right end side. The attachment metal plate 61 has a bent portion 63 bent upward on the right end side. As shown in FIG. 7 and FIG. 8, the base end portions 64 a and 64 a of two tension springs 64 and 64, which will be described later, are hooked on the front end side (right side in these drawings) of the bent portion 63. The parts 65 and 65 are formed in two places. In the present embodiment, the two attachment portions 65, 65 are arranged at positions symmetrical with respect to the center C in the front-rear direction of a window portion 67 described later. In addition, a slit 66 that is long in the front-rear direction is formed at a lower portion of the bent portion 63 between the attachment portions 65 and 65 by partially raising the portion toward the left. A contact portion 82 on the right end side of the cleaning member 52, which will be described later, protrudes from the slit 66 toward the right side.

  A rectangular window 67 that is long in the left-right direction is formed on the left side of the slit 66 in the mounting sheet metal 61. The density sensor 51 described above is disposed on the right end side of the window portion 67, and the sensor surface S is disposed so as to face the surface of the upper intermediate transfer belt 15 through the window portion 67. Yes. Of the four peripheral edges of the window portion 67, the front edge and the rear edge act as guide members 68 and 69 that guide the reciprocating movement of the cleaning member 52 described later. As shown in FIG. 8, the distance between the guide members 68 and 69 is the width (length in the front-rear direction) W1 of the window 75. The width W1 of the window 75 is set to be larger than the width W2 of the cleaning member 52 described later, and a portion corresponding to the difference between the two (= W1−W2) becomes a margin portion Y. In FIG. 8, for convenience, a case where margin portions Y having the same width are formed on the front side and the rear side of the cleaning member 52 is illustrated. Cutouts 68a and 69a are formed in the guide members 68 and 69, respectively. The cutouts 68a and 69a are used when a cleaning member 52, which will be described later, is assembled to the mounting sheet metal 61.

  As shown in FIG. 6, the above-described concentration sensor 51 is attached to the right end side and the front end side of the back surface of the attachment sheet metal 61. In this attached state, the density sensor 51 and the mounting member 53 are positioned such that the mounting member 53 is on the left side and the density sensor 51 is on the right side, as shown in FIGS. As will be described later, an opening / closing cover (opening / closing member) 47 constituting a part of the outer frame of the image forming apparatus main body M is disposed on the right side of the density sensor 51. When opened, the density sensor 51 is exposed almost to the right as shown in FIG. Therefore, the concentration sensor 51 can be easily detached from the mounting member 53 and adjusted in position.

  As shown in FIGS. 4 and 5, the density sensor 51 is arranged such that, in the mounted state, the sensor base 55 is perpendicular to the mounting sheet metal 61 and the longitudinal direction faces the front-rear direction of the image forming apparatus main body M. Has been. In addition, the rectangular window portion 67 described above is formed at a position corresponding to the sensor surface S of the density sensor 51 on the attachment metal plate 61 so that the sensor surface S faces the intermediate transfer belt 15 in parallel. It has become. Further, the position of the sensor surface S in the height direction is set so as to substantially coincide with the back surface of the mounting sheet metal 61.

  As shown in FIG. 4, the sensor surface S of the density sensor 51 is such that the center in the left-right direction (the center in the direction along the rotation direction of the intermediate transfer belt 15) faces the detection position A on the surface of the intermediate transfer belt 15. It has become. Here, the detection position A is a portion located on the surface of the tension side 15 a of the intermediate transfer belt 15 and is a position slightly downstream from the contact point B between the intermediate transfer belt 15 and the tension roller 16. This position is easy to ensure detection accuracy. That is, since this position is the tension side 15a of the intermediate transfer belt 15 and close to the tension roller 16, the front and back sides of the belt itself are compared with the loose side of the intermediate transfer belt 15 and the portion away from the roller. There is little direction fluctuation. Further, this position is flat, unlike the portion of the intermediate transfer belt 15 that is wound around the roller that forms a curved surface. For the above reason, this position is a suitable position to ensure detection accuracy. However, this position also has a drawback that scattered toner is likely to be generated. That is, the toner carried on the surface of the intermediate transfer belt 15 is held by an electric force as described above. On the other hand, since the intermediate transfer belt 15 is thick, when it is applied to the tension roller 16, the surface side is stretched. When the intermediate transfer belt 15 is detached from the tension roller 16, the elongation is eliminated. That is, the position where the detection position A is installed is in the vicinity of the position where the surface of the extended intermediate transfer belt 15 returns to the original position, so that the toner carried on the belt surface with a weak force is likely to be scattered. . That is, the sensor surface S arranged so as to face the detection position may be substantially directed upward, and thus scattered toner is likely to adhere. For this reason, the cleaning mechanism 50 becomes more effective as compared with the case where the density sensor 51 is disposed at another location.

  Next, with reference to FIGS. 4-15, the cleaning mechanism 50 which concerns on this embodiment is explained in full detail. In these drawings, members unnecessary for explanation are omitted as appropriate. 4 to FIG. 15, FIG. 4 to FIG. 6 are as described above. That is, FIG. 4 is a diagram illustrating a state in which the opening / closing cover 47 is disposed at the closed position and the cleaning member 52 is disposed at the retracted position. FIG. 5 is a diagram illustrating a state in which the opening / closing cover 47 is moved in the opening direction and the cleaning member 52 is disposed at the cleaning position. FIG. 6 is a perspective view for explaining the position of the density sensor 51. FIG. 7 is a perspective view of the mounting sheet metal 61 as a single unit as viewed from the upper left obliquely upper side. FIG. 8 shows the cleaning member 52 in the attached state as seen from the same direction as FIG. FIG. 9 is a perspective view of the cleaning member 52 as a single unit as viewed from the upper front diagonally on the left side. Note that the directions indicated by the arrows at the top of the figure are the front, rear, left, right, top and bottom of the cleaning member 52, respectively. This direction substantially coincides with the front, rear, left, right, top and bottom of the image forming apparatus main body M shown in FIG. FIG. 10 is a perspective view of the cleaning member 52 as a single unit as viewed from below. 11 to 15 are views for explaining the operation of the cleaning member 52. In this order, the opening / closing cover 47 is in a closed position, slightly opened, further opened, and slightly closed from the opened state. It shows a closed state and a closed state.

  As shown in FIG. 8, the cleaning mechanism 50 cleans the sensor surface S of the concentration sensor 51, guide members 68 and 69 that guide the reciprocating movement of the cleaning member 52, and biases the cleaning member 52. A tension spring 64 (biasing means), and an opening / closing cover (opening / closing member) 47 for reciprocating the cleaning member 52. An allowance portion Y is provided between the cleaning member 52 and the guide members 68 and 69. Further, the allowance portion A is used to make the cleaning member 52 in the width direction (on the plane where reciprocation is performed). Further, a shake generating means for generating a shake in a direction perpendicular to the reciprocating direction) is provided. In the present embodiment, the shake generating means is configured by making the spring constants of the two tension springs different from each other.

  As shown in FIGS. 8 to 10, the cleaning member 52 includes a slider 70 and a wiping member 71 held by the slider 70. The slider 70 is formed of, for example, a synthetic resin, and the wiping member 71 is formed of, for example, an acrylic pile seal.

  As shown in FIG. 9, the slider 70 is divided into three portions a, b, and c in the vertical direction in terms of its function, and becomes a mounting base 72, a guided portion 73, and a pressing portion 74 in order from the top. Yes. When the slider 70 is attached to the attachment metal plate 61, the above-described attachment pace 72 is located on the upper surface side of the attachment metal plate 61, the guided portion 73 is located corresponding to the thickness of the attachment metal plate 61, and the pressing portion 74 is positioned on the lower surface side of the mounting sheet metal 61. The mounting base 72 is formed in a rectangular plate shape that is long in the left-right direction. The mounting base 72 has a rectangular window 75 penetrating in the vertical direction (front and back direction) in the left half. The width in the front-rear direction and the left-right direction of the window 75 is set to be larger than those of the sensor surface S. That is, when the cleaning member 52 is disposed at a retracted position, which will be described later, the window 75 is disposed at a position corresponding to the sensor surface S. At this time, the sensor surface S is completely exposed, and the sensor surface S is intermediately transferred. It faces the surface of the belt 15.

  A plate-shaped attachment portion 76 that is long in the front-rear direction is formed in a portion located on the left end side of the four peripheral portions of the window portion 75. The attachment 76 part is inclined so that the right end side is a free end by slits 77 and 77 provided on the front end side and the rear end side, and the free end side is positioned below. The attachment portion 76 is capable of elastically deforming the free end side on the right end side with reference to the base end portion located on the left end side. A wiping member 71 is attached to the attachment portion 76.

  As the wiping member 71, a rectangular sheet-like member is used. The wiping member 71 is attached by, for example, a double-sided seal so as to be folded back in a “U” shape from the front surface side to the back surface side of the attachment portion 76. Accordingly, the wiping member 71 is inclined with respect to the attachment base 72 in accordance with the inclination of the attachment portion 76, and as shown in FIG. It has become. The cleaning member 52 rubs the sensor surface S of the concentration sensor 51 by the rubbing portion 78 of the wiping member 71. At this time, the wiping member 71 is pressed against the sensor surface S by the elastic deformation of the mounting portion 76 of the mounting base 72. The width (length in the front-rear direction) of the wiping member 71 is set wider than the width of the sensor surface S described above. In the present embodiment, an acrylic pile seal is used as the wiping member 71. The acrylic pile seal wipes off foreign matter such as toner, paper dust, and dust adhering to the sensor surface S by rubbing the sensor surface S in a state where the pile portion (raised portion) is crushed. It is. Here, in this embodiment, the wiping member 71 removes foreign matter from the sensor surface S by rubbing the sensor surface S directed upward. Therefore, for example, when the wiping member 71 is composed of a non-woven fabric, the non-woven fabric holds the wiped foreign matter, and when the sensor surface S is rubbed next, the held foreign matter is reversed. There is a risk of falling onto the sensor surface S. In this respect, the acrylic pile seal is difficult to hold the wiped foreign matter, so there is no such risk as described above. On the other hand, acrylic pile seals are prone to wrinkles on the raised portions with long-term use. For this reason, for example, if the operation at the time of rubbing is a simple reciprocating movement, streaks due to the raised portions are attached to the sensor surface S, and wiping unevenness is likely to occur. On the other hand, in this embodiment, as will be described later, the operation of the wiping member at the time of rubbing is made complicated and irregular. Therefore, even when the wiping member 71 that is easily wrinkled, such as an acrylic pile seal, is used, the sensor surface S can be satisfactorily cleaned over a long period of time.

  Hooks 80 and 80 are formed on the front side and the rear side of the window portion 75 in the mounting base 72, respectively. The hooks 80 are formed so as to protrude forward and backward from the mounting base 72, respectively, and the opening is directed leftward. The hooks 80, 80 are arranged at substantially the same position as the right end of the wiping member 71 with respect to the position in the left-right direction. The hooks 80 and 80 are hooked with distal ends 64b and 64b of tension springs 64 and 64 as urging members described later.

  The guided portion 73 has a front guided surface 73a on the front end side as shown in FIG. 9, and a position corresponding to the front guided surface 73a on the rear end side as shown in FIG. And a rear guided surface 73b. These front and rear guided surfaces 73a and 73b are portions that are directly guided by the guide portions 68 and 69 of the mounting sheet metal 61 described above. The guided surfaces 73a and 73b are provided on the left side of the hooks 80 and 80 of the mounting base 72 described above. As described above, the lengths of the guided surfaces 73a and 73b in the left-right direction are set to be less than half the length of the mounting base 72 in the left-right direction. Since the length of the substantially guided portion is short as described above, the cleaning member 52 is likely to swing in the width direction during the reciprocating movement. The distance between the front and back guided surfaces 73a and 73b is the width (length in the front-rear direction) W2 of the cleaning member 52. As described above, the difference between the width W2 of the cleaning member 52 and the width W1 of the window portion 75 corresponds to the margin portion Y. Here, when the cleaning member 52 is only reciprocated with respect to the margin portion Y, it is sufficient that the margin portion Y is about 0.1 mm. On the other hand, in this embodiment, about 0.25 to 1 mm is provided on one side (about 0.5 to 2 mm on both sides). As a result, the cleaning member 52 is shaken in the width direction.

  The pressing portion 74 is formed in a block shape that is long in the front-rear direction. The upper surface of the pressing portion 74 is a slide surface 81 formed in a flat shape, and the slide surface 81 is formed so as to protrude to the left, front, and rear with respect to the left end side portion of the slider 70. ing. Among the slide surfaces 81, the front slide surface 81 a and the rear slide surface 81 b projecting forward and backward are the guide members 68 of the window portion 67 when the cleaning member 52 is incorporated in the window portion 67 of the mounting sheet metal 61. It contacts the back surface of 69, and when the cleaning member 52 reciprocates, it leaves and is rubbed against this back surface.

  Here, regarding the positional relationship between the hook 80 and the pressing portion 74 in the cleaning member 52, in this embodiment, as shown in FIG. 9, the pressing portion 74 positioned on the back surface (lower surface) side of the window portion 67 is the cleaning member 52. On the other hand, the hook 80 located on the surface (upper surface) side of the window portion 67 is located on the right side of the pressing member 74. Therefore, due to the structure, in this embodiment, the cleaning member 52 can sink to the window portion 67 by lowering the left end side of the mounting base 72 located on the surface side of the mounting sheet metal 61 to some extent. . That is, the wiping member 71 can be moved up and down with respect to the mounting sheet metal 61. In combination with this and the fact that the wiping member 71 is attached to the elastically deformable attachment portion 76 as described above, when the wiping member 71 rubs the sensor surface S, the wiping member The sensor surface S is elastically sandwiched between 71 and the pressing portion 74, that is, the wiping member 71 is rubbed against the sensor surface S while being pressed with an appropriate pressing force.

  On the right end side of the mounting base 72, a contact portion 82 that engages and disengages with an engagement portion 47b of the opening / closing cover 47 described later is provided. In this embodiment, the contact part 82 is formed straight in the front-rear direction, and arcuate fulcrums 82a and 82b are formed at the front end and the rear end. As will be described later, these fulcrums make point contact with the engaging portion 47b of the opening / closing cover 47 when the cleaning member 52 is tilted with respect to the reciprocating movement direction, thereby causing the cleaning member 52 to be in an unstable state. It is intended to create positively.

  When the cleaning member 52 having the above-described configuration is incorporated into the window portion 67 of the mounting sheet metal 61, the right end side portion of the cleaning member 52 is placed in a notch 68 a of the window portion 67 in a state where the cleaning member 52 stands substantially vertically below the mounting sheet metal 61. , 69a is passed from below to above, and the hooks 80, 80 are further passed through the notches 68a, 69a, and then the right end side of the cleaning member 52 is tilted so that the whole is parallel to the mounting plate 61. To complete. In this state, as shown in FIG. 8, the above-described margin portion Y is formed between the guide members 68 and 69 and the cleaning member 52.

  As shown in FIG. 8, in this embodiment, two tension springs 64 and 64 (biasing members) are used as the urging means. The front tension spring 64 has a base end portion 64 a hung on the front mounting portion 65 and a front end portion 64 b hung on the front hook 80 of the cleaning member 52. With respect to the position along the front-rear direction, the front mounting portion 65 is positioned further to the front end side than the front hook 80, so that the front tension spring 64 has the base end portion 64a on the front side of the front end portion 64b. It is stretched diagonally so as to be positioned. The tension spring 64 urges the cleaning member 52 mainly from the retracted position side toward the cleaning position side (toward the right side) and also urges the front side. On the other hand, the rear tension spring 64 has a base end portion 64 a hung on the rear mounting portion 65 and a tip end portion 64 b hung on the rear hook 80 of the cleaning member 52. Since the rear attachment portion 65 is located further rearward than the rear hook 80 with respect to the position along the front-rear direction, the rear tension spring 65 has a base end portion 64a at the front end portion 64b. Also, it is stretched obliquely so as to be located on the rear end side. The rear tension spring 64 urges the cleaning member 52 mainly from the retracted position side toward the cleaning position side (toward the right side) and also urges the rear side.

  In the present embodiment, the vibration generating means is configured by making the spring constants of the two tension springs 64 and 64 different from each other. In other words, by changing the spring constant, a moment in the direction of rotating in the same plane with respect to the cleaning member 52 is generated. Thereby, when the cleaning member 52 reciprocates, a shake in a direction orthogonal to the reciprocating direction is generated. Hereinafter, a case where the spring constant of the front tension spring 64 is larger than the spring constant of the rear tension spring 64 will be described as an example.

  As shown in FIG. 1, the opening / closing cover 47 as an opening / closing member is disposed on the right side surface of the image forming apparatus main body M. As shown in FIGS. The side can swing. FIG. 4 shows a state in which the opening / closing cover 47 is disposed at the closed position, and FIG. 5 shows that the opening / closing cover 47 moves in the opening direction (arrow R47a direction) from the closed position toward the opening position (not shown). It shows a state in the middle. The opening / closing cover 47 is moved in the opening direction (arrow R47a direction) in FIG. 5 by the user or service person pulling the upper side from the closed position shown in FIG. 4 to the open position (not shown). Is done. Note that the open / close cover 47 is arranged in a stable state in the open position and substantially horizontally. As shown in FIG. 4, the opening / closing cover 47 has an engagement portion 47 b that engages with and disengages from the contact portion 82 of the cleaning member 52 described above on the inner portion.

  As shown in FIGS. 4 and 11, the cleaning member 52 is disposed at the retracted position retracted from the sensor surface S corresponding to the closed position of the opening / closing cover 47. That is, the contact portion 82 of the cleaning member 52 is pushed to the left against the urging force of the tension springs 64 and 64 by the engaging portion 47b of the opening / closing cover 47 (closed state) disposed in the closed position, Thereby, the cleaning member 52 is arrange | positioned in a retracted position. At this time, the cleaning member 52 is retracted from the sensor surface S of the density sensor 51 so that the sensor surface S faces the surface of the intermediate transfer belt 15. On the other hand, as shown in FIGS. 5, 13, and 14, the cleaning member 52 is biased in the opening direction of the opening / closing cover 47 by the tension springs 64, 64, so that the opening / closing cover 47 is moved in the opening direction. In conjunction with the opening operation (operation in the direction of the arrow R47a), the urging force of the tension springs 64 and 64 moves to the cleaning position side, and the wiping member 71 rubs the sensor surface S to rub the sensor surface S. Wipe off any foreign objects that have adhered to the surface. As described above, the cleaning member 52 moves from the retracted position to the cleaning position in conjunction with the opening operation of the opening / closing cover 47 from the closed position to the open position. At this time, the wiping member 71 rubs the sensor surface S. The foreign matter adhering to the sensor surface S is wiped off. On the contrary, the cleaning member 52 moves from the cleaning position to the retracted position in conjunction with the closing operation of the opening / closing cover 47 from the open position to the closed position. At this time, the wiping member 71 rubs the sensor surface S. The foreign matter adhering to the sensor surface S is wiped off. As described above, the cleaning member 52 performs a so-called cleaning operation in which the sensor surface S is rubbed with the wiping member 71 in conjunction with the opening / closing operation of the opening / closing cover 47. At this time, the wiping member 71 is rubbed while being pressed against the sensor surface S by the pressing portion 74 of the cleaning member 52, so that the foreign matter on the sensor surface S can be reliably wiped off.

  Furthermore, in the present invention, since the margin portion Y is provided between the cleaning member 52 and the guide members 68 and 69 and the spring constants of the front and rear tension springs 64 and 64 are changed as the vibration generating means, the cleaning member 52 is In the above-described cleaning operation, in addition to the reciprocating movement, a vibration in the width direction is added, and the cleaning operation is performed in a state where these motions are combined.

  A characteristic cleaning operation of the present invention will be described in detail with reference to FIGS. Among these, FIG. 11 shows a state in which the opening / closing cover 47 is disposed at the closed position and the cleaning member 52 is disposed at the retracted position. FIG. 12 shows the state of the cleaning member 52 immediately after the opening operation of the opening / closing cover 47 in the arrow R47a direction is started. FIG. 13 shows a state of the cleaning member 52 when the opening / closing cover 47 is further opened from the state of FIG. FIG. 14 is a diagram illustrating a state of the cleaning member 52 immediately after the closing operation in the direction of the arrow R47b is started. FIG. 15 shows the state of the cleaning member 52 when the opening / closing cover 47 is further closed from the state of FIG.

  As shown in FIG. 11, when the opening / closing cover 47 is disposed at the closed position, the cleaning member 52 is pushed leftward against the urging force of the tension springs 64, 64 by the opening / closing cover 47 and retracts. Placed in position. At this time, since the sensor surface S is exposed by the window portion 75, it can face the surface of the intermediate transfer belt (see FIG. 2). That is, the density sensor 51 can detect the density of the toner image formed on the surface of the intermediate transfer belt 15.

  In the present invention, as shown in FIG. 8, the width W <b> 1 of the window 67 is set larger than the width W <b> 2 of the cleaning member 52, and positively between the cleaning member 52 and the guide members 68 and 69. A margin Y is provided. In the present embodiment, as described above, the spring constant of the front tension spring 64 is set larger than the spring constant of the rear tension spring 64. Therefore, the moment by which the front and rear tension springs 64, 64 with respect to the cleaning member 52 in FIG. 11 are rotated counterclockwise exceeds the moment. However, the posture shown in FIG. 11 is stable based on the fact that the contact portion 82 at the right end of the cleaning member 52 is in contact with the engaging portion 47b of the opening / closing cover 47 over substantially the entire width thereof.

  In this state, as shown in FIG. 12, when the opening operation of the opening / closing cover 47 is started, the cleaning member 52 swings counterclockwise due to the difference in the urging force by the front and rear tension springs 64. When the opening / closing cover 47 is further opened, the right end side of the rear guide surface 73b of the cleaning member 52 collides with the rear guide portion 69, and the left end side of the front guide surface 73a is the front guide portion. 68, and the reaction force causes the cleaning member 52 to rotate clockwise, and swings in the right direction as shown in FIG. When the cleaning member 52 moves from the retracted position to the cleaning position in conjunction with the operation of the opening / closing cover 47, the above-mentioned counterclockwise and clockwise swings are repeated. When the opening / closing cover 47 is disposed at the open position and is separated from the contact portion, the opening / closing cover 47 is stably stopped at the cleaning position shown in FIG. In this state, the sensor surface S of the concentration sensor 51 is almost entirely covered by the wiping member 71 of the cleaning member 52, so that the sensor surface S may be accidentally damaged by the user or service person when the open / close cover 47 is open. There is no risk of contamination.

  Further, when the opening / closing cover 47 in the open position is closed in the closing direction (arrow R47b direction) in FIG. 14, the opening / closing cover 47 contacts the fulcrum 82a on the front side of the contact portion 82 of the cleaning member 52. . As a result, a clockwise moment acts on the cleaning member 52 and swings in the reverse direction as shown in FIG. Thus, when the opening / closing cover 47 is closed, that is, when the cleaning member 52 moves from the cleaning position to the retracted position, the counterclockwise and clockwise swings are repeated.

  As described above, the cleaning member 52 reciprocates from the retracted position to the cleaning position and from the cleaning position to the retracted position in conjunction with the opening / closing operation of the opening / closing cover 47. Since the margin portion Y and the vibration generating means are swung in the direction orthogonal to the reciprocating movement, the cleaning operation of the cleaning member 52 is a complicated operation in which the vibration is combined with the reciprocating movement. For this reason, the wiping member 71 can wipe off foreign matter adhering to the sensor surface S by rubbing and wiping with a complicated trajectory instead of a constant trajectory, thereby effectively preventing the occurrence of wiping unevenness. it can.

  In the present embodiment, the above-described margin portion Y is provided, and the tension springs 64 and 64 having different spring constants are provided as the vibration generating means. We are actively creating situations that are unstable to movement.

  The length in the left-right direction of the guide surfaces 73a, 73b guided by the guide members 68, 69 is made shorter than the length in the left-right direction of the entire cleaning member 52. Thereby, the deflection of the cleaning member 52 can be increased.

  Further, since the position of the center of gravity G (see FIG. 11) of the cleaning member is set so as to be inside the intersection of the tension spring 64 and the extension of the tension spring 64, the cleaning member 52 is swung back and forth. Tends to be unstable.

  Further, when the cleaning member 52 swings, the fulcrums 82a and 82b that are the centers of the swings are in point contact with the open / close cover 47, and the fulcrum 82a is shifted from the fulcrum 82a to the fulcrum 82b depending on the direction in which the swing center is swung. On the contrary, it will be transferred. As the fulcrums 82a and 82b move, the magnitude relationship between the two tension springs 64 and 64 changes greatly.

  In the above, the vibration generating means is configured by changing the spring constants of the front and rear tension springs 64 and 64. However, in this embodiment, the urging forces of the front and rear tension springs 64 and 64 on the cleaning member 52 are different. This is enough. In this method, in addition to changing the spring constants described above, the lengths of the two tension springs 64, 64 are changed, and the attachment portions on which the base ends 64a, 64a of the two tension springs 64, 64 are hung. The position in the left-right direction of one of the hooks 80, 80 of the cleaning member 52 on which the tip portions 64b, 64b of the two tension springs 64, 64 are changed to change the position in the front-rear direction of one of 65, 65. There are changes. As a result, the moment acting on the cleaning member 52 by the two tension springs 64 and 64 can be made different between the counterclockwise direction and the clockwise direction, and the cleaning member 52 during the reciprocating movement becomes unstable in the front-rear direction. can do.

  In the above description, the contact portion 82 of the cleaning member 52 is formed in a linear shape. Instead, for example, the contact portion is formed in a hemispherical shape provided in the center in the width direction. Also good. In this case, the cleaning member 52 is always in point contact with the opening / closing cover 47, and the instability is further increased.

<Embodiment 2>
The second embodiment will be described with reference to FIGS. 16, 17, 18, and 19. Among these, FIG. 16 is a view for explaining the shape of the window portion 83 formed in the attachment metal plate 61, and is a perspective view of the window portion 83 as viewed from the upper left oblique side. FIG. 17 is a diagram illustrating the state of the cleaning member 52 when the opening / closing cover 47 is in the closed position. FIG. 18 is a view for explaining the operation of the cleaning member 52 when the opening / closing cover 47 is opened in the opening direction. FIG. 19 is a view for explaining the operation of the cleaning member 52 when the opening / closing cover 47 is closed in the closing direction. In the present embodiment, members having the same configuration as those of the above-described first embodiment are denoted by the same reference numerals, and redundant description will be omitted as appropriate.

  As shown in these drawings, in the present embodiment, the window 83 for attaching the cleaning member 52 formed on the attachment metal plate 61 is constituted by a guide member 84 constituted by its front edge and a rear edge. A marginal portion Y is provided between the guide member 85 and the concave guide 86 in one guide member 85. The concave guide 86 is formed by providing an inclined portion in the middle portion of the guide member 85 in the left-right direction so that the width of the window portion 83 increases toward the right end side. Further, a hemispherical convex abutting portion 87 is provided on the abutting portion 82 of the cleaning member 52 so that the convex abutting portion 87 is in point contact with the engaging portion 47 b of the opening / closing cover 47. Yes. For this reason, the cleaning member 52 is in an extremely unstable state even when the convex contact portion 87 is in contact with the engagement portion 47 b of the opening / closing cover 47. For this reason, even if the cleaning member 52 is, for example, the case where the spring constants of the two tension springs 64 and 64 are set to be the same, there is an error in the dimensional accuracy and assembly accuracy of each member. As a result, it swings counterclockwise as shown in FIG. 18 or clockwise as shown in FIG. 19 during the reciprocating movement in conjunction with the opening and closing operation of the opening and closing cover 47. Since the concave guide 86 is provided, the cleaning member 52 easily swings counterclockwise or clockwise, and the swing is further increased.

<Embodiment 3>
20 and 21 show the third embodiment. Of these, FIG. 20 shows the cleaning member 52 in a state assembled to the mounting sheet metal 61. The opening / closing cover 47 is disposed at the open position. FIG. 21 is a perspective view for explaining the operation of the cleaning member during the opening operation of the opening / closing cover 47. The present embodiment is the same as the first embodiment except that the engaging portion 47b in the above-described first embodiment is replaced with an inclined portion (inclined engaging portion) 88.

  In the present embodiment, the opening / closing cover 47 is provided with an inclined portion 88 as an engaging portion that comes into contact with the cleaning member 47. When the opening / closing cover 47 that is in the closed position is opened around its fulcrum 47a, the inclined portion 88 descends as the opening degree increases. For this reason, the abutting position of the abutting portion 78 relative to the inclined portion 88 rises and moves from the front end side to the rear end side as it rises. Considering the contact portion 78 on the cleaning member 52 side as a reference, the contact position of the inclined portion 88 with respect to the contact portion 78 moves from the front end side to the rear end side in conjunction with the opening operation of the opening / closing cover 47. It will follow. When the contact position is on the front side with respect to the center in the front-rear direction of the contact portion 78, a clockwise moment acts on the cleaning member 52 from the inclined portion 88, and the center in the front-rear direction is applied. When it is on the rear side, a counterclockwise moment acts. Due to these clockwise and counterclockwise moments, the cleaning member 52 swings clockwise and swings counterclockwise. Note that, for the closing operation of the opening / closing cover 47, contrary to the above, the cleaning member 52 is first counterclockwise and then clockwise.

  According to the present embodiment, by providing the inclined portion 88 as described above, the cleaning member 52 that reciprocates between the retracted position and the cleaning position in conjunction with the opening / closing operation of the opening / closing cover 47 can be surely achieved. A counterclockwise and clockwise shake can be generated. Therefore, the wiping member 71 can wipe off the foreign matter by rubbed well without wiping the sensor surface S.

<Embodiment 4>
In this embodiment, an uneven portion (not shown) is provided on one of the guide member of the window portion of the mounting sheet metal and the guide surface of the cleaning member, and the engaging portion (not shown) that can be engaged and disengaged with the other. Is provided. When the cleaning member reciprocates in the left-right direction in conjunction with the opening / closing operation of the opening / closing cover, the engaging portion is engaged / disengaged with the concavo-convex portion, thereby causing a vibration in the width direction with respect to the cleaning member. become.

  In the above description, the cleaning mechanism 50 according to the present invention is applied to one that cleans the sensor surface S of the density sensor 51 that detects the density of the toner image carried and conveyed on the surface of the intermediate transfer belt 15 as a belt member. The case has been described as an example. The present invention is not limited to this. For example, the belt member can be applied to a belt-shaped photoreceptor, so-called photoreceptor belt (not shown). That is, the present invention can also be applied to a density sensor that detects the density of a toner image carried and conveyed on the surface of the photosensitive belt, and that cleans the sensor surface.

  The cleaning mechanism of the present invention is a sensor of a density sensor that detects the density of a toner image carried on an intermediate transfer belt or a photoreceptor belt used in an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multifunction machine thereof. Although the mode of cleaning the surface has been illustrated, the present invention is not limited to a belt member such as an intermediate transfer belt or a photosensitive belt, but a drum-shaped photosensitive drum, intermediate transfer drum, or the like. It can also be applied to cases.

FIG. 3 is a perspective view of the overall image forming apparatus as viewed from diagonally upward on the front right. FIG. 2 is a diagram schematically showing a longitudinal section when the image forming apparatus is viewed from the direction of arrow X (front side) in FIG. 1. It is a perspective view explaining how a density sensor is attached to an attachment member. It is a front view explaining the state by which the cleaning member was arrange | positioned in the retracted position by the opening / closing cover arrange | positioned in the closed position. It is a front view explaining the state by which the cleaning member was arrange | positioned in the cleaning position with the opening-and-closing cover in operation of opening from a closed position toward an open position. FIG. 3 is a perspective view of the density sensor as seen from the rear obliquely upper side on the right side of the image forming apparatus main body. It is the perspective view which looked at the attachment sheet metal as a single body from the left diagonal upper part of the front side. It is the perspective view which looked at the state where the cleaning member was attached to the attachment metal plate, and the state where the opening and closing cover 47 was opened from the upper left diagonally. It is the perspective view which looked at the cleaning member as a single body from the front diagonally upper left side. It is the perspective view which looked at the cleaning member as a single body from the downward direction. It is a figure which shows the state by which the opening / closing cover is arrange | positioned in the closed position, and the cleaning member is arrange | positioned in the retracted position. It is a figure which shows the state of the cleaning member immediately after the opening operation | movement of an opening-and-closing cover was started. It is a figure which shows the state of the cleaning member when an opening / closing cover is further opened from the state of FIG. It is a figure which shows the state of the cleaning member immediately after the closing operation of an opening / closing cover was started. It is a figure which shows the state of the cleaning member when an opening / closing cover is further closed from the state of FIG. It is a perspective view explaining the shape of the window part formed in the attachment metal plate. It is a figure explaining the state of the cleaning member when an opening-and-closing cover exists in a closed position. It is a figure explaining operation | movement of the cleaning member when the open / close cover is opened in the opening direction. It is a figure explaining operation | movement of the cleaning member 52 when an open / close cover is closed in the closing direction. It is a figure which shows the cleaning member when the opening / closing cover is arrange | positioned in the open position in the state assembled | attached to the attachment metal plate. It is a perspective view explaining operation | movement of the cleaning member during opening operation | movement of an opening / closing cover.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus, 15 ... Intermediate transfer belt (belt member), 47 ... Open / close cover (open / close member), 50 ... Cleaning mechanism, 51 ... Density sensor, 52 ... Cleaning member, 64 ... Pull Spring (biasing means, biasing member), 68, 69 ... guide member, 71 ... wiping member, 74 ... pressing part, 86 ... concave guide, 87 ... convex contact part, 88 ... tilting Part (inclined engagement part), S ... sensor surface, Y ... margin

Claims (9)

In a cleaning mechanism for wiping off foreign matter adhering to the sensor surface of an optical density sensor disposed opposite to the surface of a belt member carrying and conveying a toner image,
A cleaning member that is rubbed against the sensor surface and wipes off foreign matter adhering to the sensor surface;
A guide member that guides the cleaning member so as to reciprocate between a retreat position that exposes the sensor surface and a cleaning position that rubs the sensor surface on a plane along the sensor surface;
Biasing means for biasing the cleaning member from the retracted position side toward the cleaning position side;
The cleaning member urged by the urging means, receives the cleaning member and places the cleaning member in the retracted position, and retracts the cleaning member according to the urging force of the urging means by the opening operation from the closed position to the open position. An opening / closing member that moves the cleaning member from the cleaning position to the retracted position against a biasing force of the biasing means by a closing operation from the opening position to the cleaning position and a closing operation from the opening position to the closing position; With
Allowing the cleaning member to swing in the width direction during the reciprocating movement between the cleaning member and the guide member when a direction orthogonal to the reciprocating direction on the plane is a width direction. While providing a margin,
During the reciprocating movement with respect to the cleaning member, provided with a vibration generating means for generating a vibration in the width direction by the margin portion,
A cleaning mechanism characterized by that. The biasing means has a plurality of biasing members engaged at different positions in the width direction of the cleaning member,
The shake generating means is configured by different urging forces of the urging members with respect to the cleaning member.
The cleaning mechanism according to claim 1. The deflection generating means is configured by a concave guide provided on the guide portion side in one margin portion of the cleaning member in the width direction.
The cleaning mechanism according to claim 1. The cleaning member has a convex contact portion at a portion that contacts the opening and closing member.
The cleaning mechanism according to claim 2 or 3, wherein The shake generating means is configured by an inclined engaging portion that is provided on the opening / closing member and contacts the cleaning member,
As the opening and closing member is opened and closed, the inclined engagement portion changes a contact position with the cleaning member between one end side and the other end side in the width direction of the cleaning member. To
The cleaning mechanism according to claim 1. The vibration generating means is provided on the concavo-convex portion provided in one of the cleaning member and the guide member in the margin portion and on the concavo-convex portion provided in the other with the reciprocating movement of the cleaning member. It is comprised by the engaging part to engage / disengage,
The cleaning mechanism according to claim 1. The cleaning member rubs against the sensor surface to wipe off foreign matter adhering to the sensor surface, and prevents the wiping member from lifting when the sensor surface is rubbed by the wiping member. A pressing portion for securing the amount,
The cleaning mechanism according to claim 1, wherein: The cleaning member covers the sensor surface when disposed at the cleaning position.
The cleaning mechanism according to any one of claims 1 to 7, wherein: A belt member that carries and conveys a toner image, an image forming unit that forms a toner image on the belt member, an optical density sensor that detects the density of the toner image formed on the surface of the belt member, and the density sensor A cleaning mechanism for cleaning the sensor surface of the image forming apparatus,
The cleaning mechanism is the cleaning mechanism according to any one of claims 1 to 8.
An image forming apparatus.

Images