JP2020042177A - Image forming device - Google Patents

Abstract

To provide an image forming device with which it is possible to reduce the size of an optical box in the main scanning direction, as compared with a conventional construction, without changing the size of the optical box in the sub-scanning direction.SOLUTION: An optical box 40 comprises: a rotary polygon mirror 43; a semiconductor laser 44 as a light source; permeable members (transparent windows) (42Y, 42M, 42C, 42Bk) provided above the optical box 40, for emitting a laser beam from inside of the optical box 40 to the outside; and a cleaning mechanism for cleaning the permeable members. The cleaning mechanism is such that as a winding motor (drive motor) 55 rotates, a cleaning member is moved in the main scanning direction via a wire wound on a winding drum 59 and cleans the permeable members by rubbing. The winding motor 55 is arranged so as to be located inside, rather than both ends, of transparent members in the main scanning direction, when the optical box 40 is seen from the vertically upper side, and the size of the optical box 40 in the main scanning direction can be reduced by that much.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an image forming apparatus such as a copying machine or a printer that forms an image on a recording sheet using an electrophotographic method.

  2. Description of the Related Art Conventionally, an image forming apparatus employing an electrophotographic method is provided with an optical scanning device that forms an electrostatic latent image by irradiating a charged photosensitive drum surface with laser light. The optical scanning device includes optical components such as a light source and a mirror, and a housing that covers the optical components. An emission port for emitting light from the light source to the outside of the housing is formed at an upper portion of the housing. The emission port is closed by a transmitting member that transmits light in order to prevent foreign substances such as toner and dust from entering the housing. If a foreign substance such as toner or dust adheres to the transmission member, the light emitted from the exit port is blocked by the foreign substance, so that the optical characteristics change. As a result, there is a possibility that the quality of the image formed on the recording paper is reduced.

  Therefore, in Patent Document 1, for example, the cleaning member rubs the transmission member to remove foreign matter attached to the transmission member. This cleaning operation is automatically performed every time a predetermined number of sheets (for example, 10,000 sheets) are printed. Thus, the transparent window is periodically cleaned by the cleaning mechanism.

JP 2016-31467 A

  The drive motor for driving the cleaning mechanism needs to be provided in the optical box so as not to block the traveling path of the light emitted from the light source. In Patent Literature 1, when the optical box is viewed from above in the vertical direction, the drive motor is disposed outside the transmitting member in the main scanning direction. Therefore, the size of the optical box is increased in the main scanning direction.

  A typical configuration of the image forming apparatus according to the present invention includes a light source that emits a light beam, a rotating polygon mirror that reflects the light beam so that the light beam emitted from the light source scans a photosensitive drum, A housing formed with an emission port that passes the light beam and extends in the main scanning direction of the light beam, a transparent window that has transparency to the light beam, extends in the main scanning direction, and closes the emission port. A cleaning member that slides and cleans the transparent window, and a region inside the both ends of the transparent window in the main scanning direction when viewed from above in the vertical direction, and the vertical direction and the cleaning member. The housing so that a part thereof is located in a region opposite to a side where the light source is arranged with respect to a virtual line extending in a direction perpendicular to both the main scanning direction and passing through the center of rotation of the rotary polygon mirror. Provided in the cleaning unit A construction which is characterized in that it comprises a drive motor for driving said cleaning member to said transparent window for causing rubbing on.

  According to the image forming apparatus of the present invention, when the optical box is viewed from the upper side in the vertical direction, a part of the drive motor that drives the cleaning mechanism is located inside the end of the transmission member in the main scanning direction. Accordingly, the size of the optical box in the main scanning direction can be reduced accordingly.

FIG. 2 is a schematic sectional view of the image forming apparatus. The figure which looked at the optical box from the vertical direction upper side. FIG. 6 is a diagram for describing a cleaning mechanism in which four cleaning members are provided on one holding member. The figure which looked at the inside of an optical box from the vertical direction upper side. The figure for demonstrating an example of the arrangement | positioning position of the winding motor inside an optical box. FIG. 9 is a view for explaining another example of the location of the winding motor inside the optical box.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The dimensions, materials, shapes, relative arrangements, and the like of the components described below are not intended to limit the scope of the present invention only to them unless otherwise specified.

(Image forming device)
FIG. 1 is a schematic cross-sectional view illustrating an overall configuration of an image forming apparatus 1 according to the present embodiment. As shown in FIG. 1, the image forming apparatus 1 according to the present embodiment includes four photosensitive drums 100 corresponding to yellow (Y), magenta (M), cyan (C), and black (Bk). I have. The image forming apparatus 1 is a tandem-type color laser beam printer including four image forming units 10Y, 10M, 10C, and 10Bk that form toner images for each color. Further, the embodiment is not limited to a color image forming apparatus having a plurality of photosensitive drums 100 as shown in FIG. 1, but may be a color image forming apparatus having one photosensitive drum 100 or an image forming apparatus for forming a monochrome image. .

  The image forming apparatus 1 includes an intermediate transfer belt 20 on which a toner image formed by each of the image forming units 10Y, 10M, 10C, and 10Bk (hereinafter, also simply referred to as the image forming unit 10) is transferred. The intermediate transfer belt 20 transfers the toner images transferred from the respective image forming units 10 to the recording paper P. The image forming units 10Y, 10M, 10C, and 10Bk have substantially the same configuration except that the color of the toner used in each image forming unit 10 is different. Hereinafter, the image forming unit 10Y will be described as an example of the image forming unit 10. A duplicate description of the image forming units 10M, 10C, and 10Bk is omitted.

  The image forming unit 10 includes a photosensitive drum 100, a charging roller 12 that uniformly charges the photosensitive drum 100, and a toner that develops an electrostatic latent image formed on the photosensitive drum 100 by an optical scanning device described later with toner. The image forming apparatus includes a developing device 13 for forming an image, and a primary transfer roller 15 for transferring the formed toner image to the intermediate transfer belt 20. The primary transfer roller 15 forms a primary transfer portion between the primary transfer roller 15 and the photosensitive drum 100 via the intermediate transfer belt 20. The toner image formed on the photosensitive drum 100 is transferred to the intermediate transfer belt 20 by applying a predetermined transfer voltage to the primary transfer roller 15.

  The intermediate transfer belt 20 is an endless belt wound around a first belt transport roller 21 and a second belt transport roller 22, and rotates in the direction of arrow H. The toner image formed by each image forming unit 10 is transferred to the rotating intermediate transfer belt 20. Here, the four image forming units 10Y, 10M, 10C, and 10Bk are arranged in parallel below the intermediate transfer belt 20 in the vertical direction. As a result, the toner image formed on the photosensitive drum 100 is transferred to the intermediate transfer belt 20 in accordance with the image information of each color.

  Further, the first belt transport roller 21 and the secondary transfer roller 65 are pressed against each other with the intermediate transfer belt 20 interposed therebetween. Thus, the first belt transport roller 21 forms a secondary transfer portion between the first belt transport roller 21 and the secondary transfer roller 65 via the intermediate transfer belt 20. The recording paper P is inserted into the secondary transfer unit, and the toner image is transferred from the intermediate transfer belt 20. The transfer residual toner remaining on the surface of the intermediate transfer belt 20 is collected by a cleaning device (not shown).

  Here, each image forming unit 10 includes an image forming unit 10Y that forms a yellow toner image from the upstream side with respect to the secondary transfer unit in the rotation direction (the direction of the arrow H) of the intermediate transfer belt 20, and a magenta toner image. , An image forming unit 10C for forming a cyan toner image, and an image forming unit 10Bk for forming a black toner image.

  In addition, a laser beam (light beam) scans each photosensitive drum 100 corresponding to each color with a laser beam (light beam) vertically below each image forming unit 10 to form an electrostatic latent image on each photosensitive drum 100. Optical box (housing) 40 is provided.

  The optical box 40 houses therein a rotating polygon mirror 43 and four semiconductor lasers (light sources) (not shown) that emit laser light modulated according to image information of each color. The plurality of semiconductor lasers are light sources for exposing the corresponding photosensitive drums 100, respectively. The rotating polygon mirror 43 is rotated at a high speed by a polygon motor (not shown). Thereby, each laser beam emitted from each semiconductor laser is reflected so as to scan the photosensitive drum 100 along the rotation axis direction (main scanning direction) of each photosensitive drum 100. Each laser beam emitted from the semiconductor laser and reflected by the rotary polygon mirror 43 is guided to an optical system component such as a lens disposed inside the optical box 40, and each of the emission ports 75 provided at the upper part of the optical box 40 is provided. The light is emitted from the inside of the optical box 40 to the outside through transmission members (transparent windows) 42Y, 42M, 42C, and 42Bk (hereinafter, also simply referred to as transmission members 42) that cover the optical box 40. The laser beam emitted from the optical box 40 exposes each photosensitive drum 100.

  On the other hand, the recording paper P is accommodated in a paper cassette 2 arranged below the image forming apparatus 1. Then, the recording paper P is fed by a pickup roller 24 to a separation nip formed by a feed roller 25 and a retard roller 26. Here, the drive is transmitted so that the retard roller 26 rotates in the reverse direction when a plurality of recording sheets P are fed by the pickup roller 24. As a result, the recording paper P is conveyed one sheet at a time, thereby preventing double feeding of the recording paper P. The recording paper P transported one by one by the feed roller 25 and the retard roller 26 is transported to a transport path 27 that extends substantially vertically along the right side surface of the image forming apparatus 1.

  Then, the recording paper P is transported from the lower side in the vertical direction of the image forming apparatus 1 to the upper side through the transport path 27, and is transported to the registration roller 29. The registration roller 29 temporarily stops the transported recording paper P, and corrects the skew of the recording paper P. Thereafter, the registration roller 29 conveys the recording paper P to the secondary transfer unit at a timing at which the toner image formed on the intermediate transfer belt 20 is conveyed to the secondary transfer unit. Thereafter, the recording paper P on which the toner image has been transferred in the secondary transfer unit is conveyed to the fixing device 3, where the toner image is fixed on the recording paper P by being heated and pressed by the fixing device 3. Then, the recording paper P on which the toner image has been fixed is discharged by a discharge roller 28 to a discharge tray provided outside the image forming apparatus 1 and at an upper portion of the main body of the image forming apparatus 1.

(Cleaning mechanism)
The image forming apparatus 1 has a configuration in which the optical box 40 is provided below the image forming unit 10. Therefore, foreign matters such as toner and dust may fall on the transmitting member 42 provided on the upper part of the optical box 40 with the image forming operation. In this case, the laser light emitted to the photosensitive drum 100 via the transmission member 42 is blocked by the foreign matter. As a result, the optical characteristics may change and the quality of the image may be reduced.

  Therefore, in the present embodiment, the optical box 40 includes a cleaning mechanism for cleaning the transmission member 42. The cleaning mechanism automatically cleans the transmitting member 42 every time, for example, about 10,000 sheets are printed. As described above, since the cleaning operation is automatically performed each time a predetermined number of sheets are printed, the user can continue to use the image forming apparatus 1 without having to worry about cleaning the transparent member 42. Further, the image forming apparatus 1 of the present embodiment also has a function of executing a cleaning operation in a manual mode when the user feels the need for cleaning. Hereinafter, the optical box 40 and the cleaning mechanism provided in the optical box 40 will be described in detail. When a direction perpendicular to both the rotation axis direction and the vertical direction of the photosensitive drum 100 is defined as a sub-scanning direction, the left side in FIG. 1 is “one end side of the image forming apparatus 1 in the sub-scanning direction” and the right side in FIG. Is defined as “the other end of the image forming apparatus 1 in the sub-scanning direction”. Therefore, for example, the term “one end of the optical box 40 in the sub-scanning direction” indicates the left side of the optical box 40 in FIG. 1, and the term “the other end of the optical box 40 in the sub-scanning direction” indicates the optical axis in FIG. Represents the right side of box 40.

  FIG. 2 is a diagram of the optical box 40 as viewed from above in the vertical direction. As shown in FIG. 2, the optical box 40 has a cover 46 that can be attached to and detached from the optical box 40. Since the image forming apparatus 1 according to the present embodiment is a tandem-type color printer, the cover 46 has emission ports 75Y, 75M, 75C, 75Bk (hereinafter, referred to as four colors) corresponding to the photosensitive drums 100 of each color. (Emission port 75 is simply referred to). As shown in FIG. 2, the emission ports 75 corresponding to the photosensitive drums 100 for four colors are formed at intervals along a direction (sub-scanning direction) perpendicular to both the vertical direction and the main scanning direction. ing. Here, the main scanning direction and the sub-scanning direction are indicated by arrows in FIG.

  The shape of each emission port 75 is a short shape that is long in the main scanning direction of the laser beam that scans the photosensitive drum 100. In other words, each emission port 75 has a rectangular shape extending in the rotation axis direction of the photosensitive drum 100.

  Each of the emission ports 75 is closed by the transmission member 42. That is, the transmissive members 42Y, 42M, 42C, and 42Bk (hereinafter, also simply referred to as the transmissive member 42) are provided at a total of four locations on the cover 46 corresponding to the emission ports 75Y, 75M, 75C, and 75Bk, respectively. The transmission member 42 is also a short member that is long in the main scanning direction of the laser beam, like the emission port 75. The transmitting member 42 is made of a transmissive material that transmits laser light. Therefore, laser light emitted by the semiconductor laser in the optical box 40 can be emitted to the photosensitive drum 100. The transmission member 42 closes the emission port 75 formed in the cover 46, thereby preventing foreign substances such as toner and dust from entering the optical box 40. In addition, although each transmission member 42 of this embodiment is made of glass, it may be made of plastic.

  Further, in the present embodiment, the sizes of the transmission members 42Y to 42Bk are set to be larger than the openings of the respective output ports 75, and the transmission members 42Y to 42Bk are configured to overlap and cover the respective output ports 75. . Then, the transmission members 42Y to 42Bk are fixed to the cover 46 by bonding an overlapping portion to the emission port 75 of the transmission members 42Y to 42Bk.

  Each transmissive member 42 corresponds to yellow (Y), magenta (M), cyan (C), and black (Bk) in order from the right side in FIG. For example, the rightmost transmission member 42Y in FIG. 2 closes the emission port 75Y through which the laser beam for scanning the yellow photosensitive drum 100 passes. In addition, for example, the leftmost transmission member 42Bk in FIG. 2 closes the emission port 75Bk through which the laser beam for scanning the black photosensitive drum 100 passes. Note that the longitudinal direction of the transmitting members 42Y to 42Bk is substantially equal to the scanning direction of the laser light emitted from each emission port 75. Further, in the present embodiment, the longitudinal direction of the transmission members 42Y to 42Bk is substantially equal to the rotation axis direction of each photosensitive drum 100.

  As described above, the optical box 40 is covered with the cover 46 and the transmissive members 42Y to 42Bk, so that foreign matters such as toner, paper dust, and dust do not enter the inside of the optical box 40. In addition, by adhering and fixing the transmission members 42Y to 42Bk larger than the emission port 75 on the cover 46, foreign substances such as toner, paper dust, and dust falling from above the optical box 40 are emitted to the transmission members 42Y to 42Bk. It is prevented from entering the inside of the optical box 40 through the gap between the openings 75Y to 75Bk.

  In the present embodiment, a cleaning mechanism is provided for cleaning foreign substances that fall onto the upper surface of the optical box 40 (the upper surfaces of the transmission members 42Y to 42Bk) from above. Here, the upper surfaces of the transmission members 42Y to 42Bk are surfaces outside the optical box 40, and are surfaces on the side from which the laser light passing through the transmission members 42Y to 42Bk is emitted.

  The cleaning mechanism is mounted on the cover 46 of the optical box 40 and on the side facing the image forming unit 10. The cleaning mechanism includes cleaning members 53Y to 53Bk for cleaning by sliding the upper surfaces of the transmission members 42Y to 42Bk, and a holding member 51a that holds the cleaning members 53Y to 53Bk and moves on the transmission members 42Y to 42Bk. And a holding member 51b. That is, a total of four cleaning members 53 and transmission members 42 are provided corresponding to the respective colors of yellow, magenta, cyan, and flack.

  The holding member 51a and the holding member 51b will be described with reference to FIG. The holding member 51a holds the cleaning member 53Y and the cleaning member 53M. The cleaning member 53Y cleans the transmitting member 42Y through which the laser light corresponding to yellow passes, and the cleaning member 53M slides and cleans the transmitting member 42M through which the laser light corresponding to magenta passes. Here, the cleaning member 53Y and the cleaning member 53M are made of, for example, silicon rubber, nonwoven fabric, or the like. The holding member 51a is provided in the optical box 40 so as to straddle two adjacent transmission members 42Y and 42M. The holding member 51a is fixed to the wire 70. That is, the cleaning members 53 are provided at both ends of the holding member 51a via the wires 70, respectively. The wire 70 is stretched around a plurality of pulleys 72a, 72c, 73a, 73c provided on the cover 46 so as to surround the yellow transmitting member 42Y, and is arranged in an annular shape. As will be described in detail later, when the winding motor (drive motor) 55 rotates, the winding drum 59 rotates. A wire 70 is wound around the winding drum and fixed. Therefore, when the winding drum 59 rotates, the wire 70 stretched over the pulley 72 or the pulley 73 moves, and the holding member 51a moves in the main scanning direction.

  The holding member 51b includes a cleaning member 53C and a cleaning member 53Bk. The cleaning member 53C cleans the transmitting member 42C through which the laser beam corresponding to cyan passes, and the cleaning member 53Bk slides and cleans the transmitting member 42Bk through which the laser beam corresponding to black passes. Here, the cleaning member 53C and the cleaning member 53Bk are made of, for example, silicon rubber, nonwoven fabric, or the like. The holding member 51b is provided in the optical box 40 so as to straddle two adjacent transmission members 42C and 42Bk. The holding member 51b is fixed to the wire 71. That is, the cleaning member 53C and the cleaning member 53Bk are provided at both ends of the holding member 51b via the wire 71, respectively. The wire 71 is stretched over a plurality of pulleys 72b, 72c, 73b, 73c provided on the cover 46 so as to surround the three transmission members 42Y to 42C, and is arranged in an annular shape. As will be described in detail later, when the winding motor 55 rotates, the winding drum 59 rotates. A wire 71 in addition to the wire 70 is wound around the winding drum 59 and fixed. Therefore, when the winding drum 59 rotates, the wire 71 stretched on the pulley 72 or the pulley 73 moves, and the holding member 51b moves in the main scanning direction.

  The winding motor 55 is configured to be able to rotate forward and backward. Therefore, the wire 70 and the wire 71 are wound up and pulled out by the winding drum 59 when the winding drum 59 is rotated by the forward rotation or the reverse rotation of the winding motor 55. As described above, the wire 70 and the wire 71 can be annularly run on the cover 46 in a state of being stretched around the pulleys 72a to 72c and the pulleys 73a to 73c by being wound and pulled out by the winding drum 59. ing.

  The take-up motor 55 is arranged such that at least a part thereof is located inside both ends of the transmission members 42Y to 42Bk in the main scanning direction when the optical box 40 is viewed from above in the vertical direction. By arranging the winding motor 55 in this way, it is possible to suppress an increase in the size of the optical box 40 in the main scanning direction.

  In the present embodiment, two members, the holding member 51a and the holding member 51b, are used. However, one member that holds the cleaning members 53Y to 53Bk may be used. FIG. 3 is a diagram for explaining a cleaning mechanism in which four cleaning members 53Y to 53Bk are provided on one holding member 51c.

  As shown in FIG. 3, the holding member 51c is provided in the optical box 40 so as to straddle the four transmission members 42Y to 42Bk in the sub-scanning direction. The holding member 51c is fixed to the wire 54. That is, two cleaning members 53 are provided at both ends of the holding member 51c via the wires 54, respectively. The wire 54 is stretched over a plurality of pulleys 72c, 72d, 73c, 73d provided on the cover 46 so as to surround the transmission member 42Y corresponding to yellow and the transmission member 42M corresponding to magenta, and is arranged in an annular shape. I have. As will be described in detail later, when the winding motor (drive motor) 55 rotates, the winding drum 59 rotates. A wire 70 is wound around the winding drum and fixed. Therefore, when the winding drum 59 rotates, the wire 54 stretched over the pulleys 72c, 72d, 73c, 73d moves, and the holding member 51c moves in the main scanning direction.

  FIG. 4 is a view of the inside of the optical box 40 when the cover 46 is removed from the optical box 40 when viewed from above in the vertical direction. The optical box 40 includes a semiconductor laser 44 as a light source, a rotating polygon mirror 43 that reflects and scans laser light emitted from the semiconductor laser 44, a motor unit 41 that rotates the rotating polygon mirror 43, and a rotating polygon mirror 43. An optical member 45 through which the reflected laser light passes is provided. The rotary polygon mirror 43 is provided inside the optical box 40 at one end of the optical box 40 in the sub-scanning direction, and rotates about a rotation center axis 48 as a rotation center.

  As illustrated in FIG. 4, the winding motor 55 and the winding drum 59 extend along a vertical direction perpendicular to both the vertical direction and the main scanning direction, and pass through the rotation center axis 48 of the rotary polygon mirror 43. With respect to the line K, it is arranged in a region opposite to the side where the semiconductor laser 44 is arranged. This is because this area is a dead space inside the optical box 40, and by arranging the winding motor 55 and the winding drum 59 in this area, the size of the optical box 40 in the main scanning direction can be reduced. It is because it can do.

  Inside the optical box 40, the laser light emitted from the semiconductor laser 44 travels toward the transmitting member 42 while being reflected and polarized by the rotating polygon mirror 43 and the optical member 45. Therefore, the winding motor 55 needs to be disposed inside the optical box 40 so as not to block the traveling path of the laser light. For example, the winding motor 55 cannot be disposed between the rotary polygon mirror 43 and the semiconductor laser 44. Thus, the position where the winding motor 55 can be arranged inside the optical box 40 is limited.

  As shown in FIG. 4, an optical system component corresponding to the semiconductor laser 44 does not exist in a portion of the semiconductor laser 44 which is symmetric with respect to the virtual line K. Therefore, this part is a dead space inside the optical box 40. The feature of the present invention resides in that the winding motor 55 is arranged in this dead space. By arranging the winding motor 55 as shown in FIG. 4, a part of the winding motor 55 can be arranged inside both ends of the transmission members 42Y to 42Bk in the main scanning direction. The width in the direction can be reduced.

  In the present embodiment, when the optical box 40 is viewed from the upper side in the vertical direction, the take-up motor 55 is configured such that, of the two ends of the optical box 40 in the sub-scanning direction, the end closer to the rotary polygon mirror 43 and the transmission member 42Y. It is arranged in the area between. In other words, the take-up motor 55 is disposed in a region between the transmission member 42Y and a wall surface on one end side of the optical box 40 in the sub-scanning direction. This area is a space necessary for providing the rotating polygon mirror 43 and the motor unit 41. Therefore, even when the winding motor 55 and the winding drum 59 are arranged in this space, the width of the optical box 40 in the sub-scanning direction can be larger than when the winding motor 55 is not arranged in this area. Absent.

  FIG. 5 is a diagram for describing the location of the winding motor 55. The arrangement of the winding motor 55 inside the optical box 40 described above will be described below with reference to FIG. When the optical box 40 is viewed from above in the vertical direction, the take-up motor 55 includes a region (region X in FIG. 5) inside both ends of the transmission member 42 in the main scanning direction and a rotating polygon mirror extending in the sub-scanning direction. A region (region Y in FIG. 5) on the side opposite to the side on which the semiconductor laser 44 is disposed with respect to the virtual line K passing through the rotation center axis 48 of the 43 (region Y in FIG. 5). The optical box 40 is provided so that a part of the winding motor 55 is located in the region Z). Naturally, the winding motor 55 is installed in the optical box 40 while avoiding the traveling path of the laser light.

  FIG. 6 illustrates the winding motor 55 and the winding drum 55 so that the winding motor 55 and the winding drum 59 are positioned between the transmission member 42M and the transmission member 42Y when the optical box 40 is viewed from the upper side in the vertical direction. FIG. 3 is a diagram in which a drum 59 is installed in an optical box 40. In this manner, if the traveling path of the laser beam is not blocked, the winding motor 55 and the winding drum 59 may be disposed on the transmission member 42Y as shown in FIG. Can be arranged inside the optical box 40. 4, the winding motor 55 can be disposed without changing the distance between the transmitting member 42M and the transmitting member 42Y in the sub-scanning direction. Therefore, the width of the optical box 40 in the sub-scanning direction does not increase. Therefore, even when the winding motor 55 is arranged as shown in FIG. 6, the size of the optical box 40 in the main scanning direction can be reduced without changing the size of the optical box 40 in the sub-scanning direction, as compared with the conventional configuration. Can be

Reference Signs List 40 optical box 41 motor unit 42 transmitting member 43 rotating polygon mirror 44 semiconductor laser 48 center axis of rotation 55 winding motor 59 winding drum K virtual line

Claims (5)

A light source for emitting a light beam;
A rotating polygon mirror that reflects the light beam so that the light beam emitted from the light source scans a photosensitive drum,
A housing formed with an emission port that passes the light beam and extends in the main scanning direction of the light beam;
A transparent window that has transparency to the light beam and extends in the main scanning direction to close the emission port,
A cleaning member for rubbing and cleaning the transparent window,
When viewed from above in the vertical direction, the rotating polygonal surface extends in a region inside both ends of the transparent window in the main scanning direction and perpendicular to both the vertical direction and the main scanning direction. The casing is provided so that a part thereof is located in a region opposite to a side on which the light source is disposed with respect to a virtual line passing through the center of rotation of the mirror, and the cleaning member slides the transparent window. And a driving motor for driving the cleaning member. The photosensitive drums are provided for four colors of black, cyan, magenta, and yellow.
The emission ports are arranged side by side at four locations of the housing at intervals in a direction along the virtual line, corresponding to the respective photosensitive drums for four colors,
The transparent windows are provided at four locations of the housing to close the emission openings corresponding to the emission openings formed at four locations of the housing,
The image forming apparatus according to claim 1, wherein four cleaning members are provided corresponding to each of the transparent windows provided at four locations of the housing.   The drive motor is provided at one end side of a transparent window provided at one end side of the housing in a direction along the virtual line, among transparent windows provided at four places of the housing. The image forming apparatus according to claim 2, wherein Two of the transparent windows provided at four positions of the housing, the transparent window provided at the position closest to one end side of the housing in the direction along the virtual line and the transparent window adjacent to the transparent window. A holding member for holding the cleaning member provided corresponding to each of the transparent windows,
The said drive motor moves the said holding member from the one end side of the said housing | casing in the said main scanning direction to the other end side, and simultaneously cleans the two transparent windows, The Claims 1 or 2 characterized by the above-mentioned. The image forming apparatus according to claim 2. A holding member for holding four cleaning members provided corresponding to each of the transparent windows provided at four locations of the housing,
The drive motor moves the holding member from one end side to the other end side of the housing in the main scanning direction to simultaneously clean transparent windows provided at four locations of the housing. The image forming apparatus according to claim 1.

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