JP2019015751A - Cleaning mechanism for transparent cover part of optical scanner, and optical scanner including the cleaning mechanism - Google Patents

Abstract

In an optical scanning device including a holding member 53 configured to move along a screw shaft 52 by rotating the screw shaft 52, the screw shaft 52 is held only by rotating in one direction. The member 53 can be reciprocated along the screw shaft 52. A groove portion formed in a screw shaft includes a first spiral groove and a second spiral groove that are opposite in phase to each other and intersect each other, and are formed in a holding member. The part includes a first protrusion 53d that engages with the first spiral groove 52a and a second protrusion 53e that engages with the second spiral groove 52b. [Selection] Figure 10

Description

  The present invention relates to a cleaning mechanism for a transparent cover portion of an optical scanning device and an optical scanning device provided with the cleaning mechanism.

  An image forming apparatus that employs an electrophotographic system such as a copying machine or a printer includes an optical scanning device that emits light for forming an electrostatic latent image on a photosensitive member, and an electrostatic latent image formed on the photosensitive member as a toner. And a developing device for developing as an image.

  The optical scanning device has a housing that houses a polygon mirror, an imaging lens, and the like. The housing is formed with an emission port through which light is emitted. The emission port is closed by a cover part such as transparent dustproof glass.

  By the way, when dirt or dust due to toner or the like adheres to the surface of the dust-proof glass, there is a problem in that the optical characteristics of the optical scanning device deteriorate and image defects occur. On the other hand, Patent Document 1 discloses a cleaning mechanism that periodically cleans the surface of dust-proof glass.

  The cleaning mechanism of Patent Literature 1 includes a screw shaft disposed along the dust-proof glass, a holding member screwed to the screw shaft, and a cleaning member held by the holding member. A protrusion that engages with the screw groove of the screw shaft is formed on the inner peripheral surface of the holding member. Then, by rotating the screw shaft forward and backward, the cleaning member is reciprocated along the dust-proof glass together with the holding member to clean the surface of the dust-proof glass. A motor for rotating the screw shaft forward and backward is housed inside the optical scanning device, and the power of the motor is transmitted to the screw shaft through a plurality of gears.

JP 2009-143108 A

  However, the optical scanning device disclosed in Patent Document 1 has a problem in that a dedicated motor for rotating the screw shaft is provided in the optical scanning device, resulting in an increase in size and cost of the optical scanning device.

  Therefore, it can be considered that a motor for rotating the screw shaft is also used as an external motor (for example, a conveyance motor) mounted on the image forming apparatus.

  However, when the external motor is a motor that rotates only in one direction (only forward rotation), the screw shaft cannot be rotated in both forward and reverse directions. Replacing the external motor with a motor that can rotate in both forward and reverse directions eliminates this problem, but increases the cost of the external motor.

  The present invention has been made in view of the above points, and an object of the present invention is to perform optical scanning that can reciprocate a holding member along the screw shaft without rotating the screw shaft in both forward and reverse directions. An object of the present invention is to provide a cleaning mechanism for the transparent cover portion of the apparatus.

  The present invention is directed to a cleaning mechanism for the transparent cover portion of an optical scanning device having a housing in which a light emission port is formed and a transparent cover portion for closing the light emission port.

  And a screw shaft disposed along the transparent cover portion and having a spiral groove formed on a peripheral surface thereof, a bearing portion provided in the housing and rotatably supporting the screw shaft, and the screw shaft. An engaging portion that engages with the groove portion is formed, and the holding member is configured to move along the screw shaft as the screw shaft rotates, and the holding member is held by the holding member, and the holding member moves. A cleaning member for cleaning the surface of the transparent cover portion, and the groove portion includes a first spiral groove and a second spiral groove whose lead angles are opposite to each other and intersect each other, and the engagement portion Includes a first protrusion that engages with the first spiral groove and a second protrusion that engages with the second spiral groove.

  According to the present invention, the holding member can be reciprocated along the screw shaft without rotating the screw shaft in both forward and reverse directions.

FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus equipped with an optical scanning device having a cleaning mechanism in the embodiment. FIG. 2 is an external perspective view of the optical scanning device. FIG. 3 is a schematic view showing an internal structure in the housing body of the optical scanning device.

FIG. 4 is a plan view showing the automatic cleaning unit. FIG. 5 is a view in the direction of the arrow V in FIG. 6 is a view in the direction of the arrow VI in FIG. FIG. 7 is an enlarged perspective view showing an end portion of the screw shaft. FIG. 8 is an enlarged perspective view showing the cylindrical nut portion of the holding member and its periphery in an enlarged manner. FIG. 9 is a cross-sectional view of the cylindrical nut portion of the holding member cut along the axis. It is sectional drawing which cut | disconnected the automatic cleaning part along the axis line of the cylindrical nut part, Comprising: The holding member has shown the state which is moving toward the other side from the one side of a main scanning direction. It is sectional drawing which cut | disconnected the automatic cleaning part along the axis line of the cylindrical nut part, Comprising: The holding member has shown the state which is moving toward the one side from the other side of the main scanning direction.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiment.

  FIG. 1 is a schematic configuration diagram of an image forming apparatus 1 according to an embodiment of the present invention. In the following description, the front side and the rear side mean the front side and the rear side (the front side and the rear side in the direction perpendicular to the paper surface in FIG. 1), and the left side and the right side refer to the image forming apparatus 1 from the front side. It means the left side and the right side when viewed.

  The image forming apparatus 1 is a tandem color printer, and includes an image forming unit 3 in a box-shaped casing 2. The image forming unit 3 transfers and forms an image on the recording paper P based on image data transmitted from an external device such as a computer connected to a network. An optical scanning device 4 that emits laser light is disposed below the image forming unit 3, and a transfer belt 5 is disposed above the image forming unit 3. A paper storage unit 6 that stores the recording paper P is disposed below the optical scanning device 4, and a manual paper feed unit 7 is disposed on the left side of the paper storage unit 6. On the right side and the upper side of the transfer belt 5, a fixing unit 8 that performs a fixing process on an image transferred and formed on the recording paper P is disposed. Reference numeral 9 denotes a paper discharge unit that is disposed on the casing 2 and discharges the recording paper P that has been subjected to fixing processing by the fixing unit 8.

  The image forming unit 3 includes four image forming units 10 arranged in a line along the transfer belt 5. These image forming units 10 have a photosensitive drum 11. A charger 12 is disposed immediately below each photoconductive drum 11, a developing device 13 is disposed on the left side of each photoconductive drum 11, and a primary transfer roller 14 is disposed directly above each photoconductive drum 11. A cleaning unit 15 for cleaning the peripheral surface of the photoconductive drum 11 is disposed on the right side of each photoconductive drum 11.

  Each photosensitive drum 11 is charged with a constant peripheral surface by a charger 12, and the laser corresponding to each color based on image data input from the computer or the like is applied to the peripheral surface of the photosensitive drum 11 after charging. Light is irradiated from the optical scanning device 4, and an electrostatic latent image is formed on the peripheral surface of each photosensitive drum 11. Developer is supplied to the electrostatic latent image from the developing device 13, and a yellow, magenta, cyan, or black toner image is formed on the peripheral surface of each photosensitive drum 11. These toner images are respectively transferred to the transfer belt 5 by a transfer bias applied to the primary transfer roller 14.

  Reference numeral 16 denotes a secondary transfer roller disposed in contact with the transfer belt 5 below the fixing unit 8, and is recorded on the sheet conveyance path 17 from the sheet storage unit 6 or the manual sheet feeding unit 7. The paper P is sandwiched between the secondary transfer roller 16 and the transfer belt 5, and the toner image on the transfer belt 5 is transferred to the recording paper P by the transfer bias applied to the secondary transfer roller 16.

  The fixing unit 8 includes a heating roller 18 and a pressure roller 19. The toner image transferred onto the recording paper P is heated by holding the recording paper P between the heating roller 18 and the pressure roller 19 while being pressed. Is fixed to the recording paper P. The recording paper P after the fixing process is discharged to the paper discharge unit 9. Reference numeral 20 denotes a reversing conveyance path for reversing the recording paper P discharged from the fixing unit 8 during double-sided printing.

-Details of optical scanning device-
FIG. 2 is an external perspective view of the optical scanning device 4. The optical scanning device 4 includes a sealed box-shaped housing 40. The housing 40 includes a bottomed box-shaped housing main body 41 that opens on the ceiling side, and a lid member 42 that closes the ceiling side of the housing main body 41.

  FIG. 3 is a cross-sectional view showing a state where the lid member 42 is removed from the housing 40 of the optical scanning device 4. A polygon mirror 43 and a drive motor 44 that rotationally drives the polygon mirror 43 are disposed at the center of the bottom wall portion of the housing body 41. The polygon mirror 43 deflects and scans a laser beam for writing an electrostatic latent image corresponding to each color of magenta (M), cyan (C), yellow (Y), and black (K) emitted from a light source. A total of four scanning optical systems S are arranged on the bottom wall of the housing body 41, two on each side of the polygon mirror 43. The four scanning optical systems S guide laser beams corresponding to the respective colors of magenta (M), cyan (C), yellow (Y), and black (K) to the surface of each photosensitive drum 11. These scanning optical systems S are composed of, for example, an fθ lens, a reflection mirror, and the like.

  As shown in FIG. 2, the lid member 42 is formed with four rectangular emission ports 45 through which the laser beams emitted from the respective scanning optical systems S pass. These emission openings 45 are covered with a transparent dustproof glass (transparent cover part) 46 that transmits light. Each emission port 45 and each dustproof glass 46 covering them are formed in a rectangular plate shape that is long in the main scanning direction.

  The surface of each dustproof glass 46 is automatically cleaned by an automatic cleaning mechanism 50. The automatic cleaning mechanism 50 includes a first automatic cleaning unit 50A and a second automatic cleaning unit 50B. The first automatic cleaning unit 50A and the second automatic cleaning unit 50B are arranged symmetrically with respect to the center position in the longitudinal direction of the housing 40. The first automatic cleaning section 50A cleans the two dustproof glasses 46 through which the magenta (M) and cyan (C) laser beams pass. The second automatic cleaning unit 50B cleans the two dustproof glasses 46 through which the yellow (Y) and black (K) laser beams pass. The first automatic cleaning unit 50A and the second automatic cleaning unit 50B are driven by a common drive motor 60 (shown only in FIG. 1). In the present embodiment, the drive motor 60 is configured separately from the optical scanning device 4 as described later.

  The first automatic cleaning unit 50A and the second automatic cleaning unit 50B have the same configuration. As shown in FIGS. 4 and 5, each of the automatic cleaning units 50 </ b> A and 50 </ b> B (only the second automatic cleaning unit 50 </ b> B is shown in each drawing) includes a screw shaft 52 and a holding member 53 that is reciprocally driven by the screw shaft 52. And a pair of cleaning members 51 (shown only in FIG. 5) held by the holding member 53.

  The screw shaft 52 is disposed so as to extend in the main scanning direction. Both ends in the axial direction of the screw shaft 52 are rotatably supported by bearings (not shown) formed on the lid member 42 of the housing 40. A drive gear 55 (shown only in FIG. 2) is attached to one end of the screw shaft 52. The drive gear 55 meshes with an idle gear 56 supported on the side wall surface of the housing body 41. The idle gear 56 is coupled to the drive motor 60 via a gear mechanism provided in the image forming apparatus 1 when the optical scanning device 4 is assembled at a predetermined position of the image forming apparatus 1. The drive motor 60 has both a function of driving the automatic cleaning units 50A and 50B of the optical scanning device 4 and a function of driving a paper transport roller in the image forming apparatus 1. That is, the drive motor 60 that drives each of the automatic cleaning units 50A and 50B is also used as the drive motor 60 for the paper transport roller provided in the image forming apparatus 1. The drive motor 60 is configured to be rotatable only in one direction (forward rotation direction).

  As shown in FIG. 6, a groove is formed on the outer peripheral surface of the screw shaft 52. The groove portion includes a first spiral groove 52a and a second spiral groove 52b. The first spiral groove 52 a and the second spiral groove 52 b are formed in a spiral shape around a common axis along the outer peripheral surface of the screw shaft 52. The axis of the screw shaft 52 and the axis of each of the spiral grooves 52a and 52b coincide. The first spiral groove 52 a and the second spiral groove 52 b are formed over the entire axial direction of the screw shaft 52.

  The first spiral groove 52 a and the second spiral groove 52 b intersect in an X shape when viewed from the radial direction of the screw shaft 52. That is, the first spiral groove 52a and the second spiral groove 52b are formed such that the lead angles are in opposite phases. The absolute value of the lead angle of the first spiral groove 52a is equal to the absolute value of the lead angle of the second spiral groove 52b.

  As shown in FIG. 7, one side ends of the first spiral groove 52 a and the second spiral groove 52 b in the spiral axis direction (axial direction of the screw shaft 52) are continuous at one side end of the screw shaft 52. Connected. Similarly, the other end portions of the first spiral groove 52a and the second spiral groove 52b in the spiral axis direction (axial direction of the screw shaft 52) are the other end portions of the screw shaft 52 (not shown in FIG. 7). ) Are connected continuously.

  As shown in FIGS. 4, 5, and 8, the holding member 53 has a cylindrical nut portion 53a, a first holding plate portion 53b, and a second holding plate portion 53c. The cylindrical nut portion 53 a is formed in a substantially cylindrical shape and is externally attached to the screw shaft 52. On the inner peripheral surface of the cylindrical nut portion 53a, a first spiral protrusion (engagement portion) 53d that engages with the first spiral groove 52a and a second spiral protrusion that engages with the second spiral groove 52b. (Engaging part) 53e is formed. The first spiral protrusion 53d and the second spiral protrusion 53e protrude radially inward from the inner peripheral surface of the cylindrical nut portion 53a. As shown in FIG. 9, the first spiral protrusion 53d and the second spiral protrusion 53e are formed such that the lead angles are in opposite phases. The absolute value of the lead angle of the first spiral protrusion 53d is equal to the absolute value of the lead angle of the second spiral protrusion 53e.

  The first holding plate portion 53b extends from the upper end portion of the cylindrical nut portion 53a to one side in the main scanning direction, and the second holding plate portion 53c extends from the upper end portion of the cylindrical nut portion 53a to the other side in the main scanning direction. Extends to the side. The cleaning members 51 (see FIG. 5) are attached to the lower surfaces of the first holding plate portion 53b and the second holding plate portion 53c, respectively.

  Each cleaning member 51 is formed of an elastic blade member (for example, a silicon pad). Each cleaning member 51 is provided at a position corresponding to a pair of dustproof glasses 46 to be cleaned by each automatic cleaning unit 50A, 50B. That is, each cleaning member 51 is provided at a position overlapping each dustproof glass 46 in plan view. Each cleaning member 51 is sandwiched between the holding plate portions 53b and 53c and the dust-proof glass 46 and compressed with a light load in the thickness direction. Thereby, each cleaning member 51 is pressed against the dust-proof glass 46 with a predetermined pressing force.

  Next, the operation of the automatic cleaning mechanism 50 will be described with reference to FIGS. When the automatic cleaning mechanism 50 is operated, the screw shaft 52 is rotated in the forward direction (in the direction indicated by the two-dot chain line in the figure and the other side in the main scanning direction) by the drive motor 60 (shown only in FIG. 1). (Clockwise as viewed from the side). As the screw shaft 52 rotates, the holding member 53 reciprocates in the main scanning direction (the axial direction of the screw shaft 52).

  In a state where the holding member 53 is moved from one side to the other side in the main scanning direction, as shown in FIG. 10, the groove side surface 52j of the first spiral groove 52a contacts the side surface 53k of the first spiral protrusion 53d. Touch. In this state, when the screw shaft 52 rotates in the forward rotation direction, the side surface 53k of the first spiral protrusion 53d of the holding member 53 is moved from one side to the other side in the main scanning direction by the groove side surface 52j of the first spiral groove 52a. Is pressed toward. As a result, the holding member 53 moves from one side to the other side in the main scanning direction. When the holding member 53 reaches the other end portion of the screw shaft 52, as shown in FIG. 11, there is a gap between the side surface 53k of the first spiral protrusion 53d and the groove side surface 52j of the first spiral groove 52a. While the gap is generated, the groove side surface 52n of the second spiral groove 52b contacts the side surface 53m of the second spiral protrusion 53e of the holding member 53. Since the screw shaft 52 continues to rotate in the forward rotation direction, the side surface 53m of the second spiral protrusion 53e of the holding member 53 is shifted from the other side in the main scanning direction to the one side by the groove side surface 52n of the second spiral groove 52b. It is pushed toward. Thereby, the holding member 53 starts to move from the other side in the main scanning direction to one side. After that, when the holding member 53 reaches one end portion in the main scanning direction of the screw shaft 52, it is between the groove side surface 52n of the second helical groove 52b and the side surface 53m of the second helical protrusion 53e of the holding member 53. While a gap is generated, the groove side surface 52j of the first spiral groove 52a contacts the side surface 53k of the first spiral protrusion 53d (returns to the contact state similar to FIG. 10). In this state, when the screw shaft 52 rotates in the forward rotation direction, the holding member 53 starts to move from one side to the other side in the main scanning direction. By repeating the above operation, the holding member 53 reciprocates in the main scanning direction along the screw shaft 52, and the cleaning of the surface of the dustproof glass 46 by the cleaning member 51 is executed.

  As described above, in the above embodiment, the holding member 53 can be reciprocated in the main scanning direction by rotating the screw shaft 52 only in one direction (forward rotation direction). Therefore, there is no need to rotate the drive motor 60 for driving the screw shaft 52 in both forward and reverse directions, so that an inexpensive motor can be used and the product cost can be reduced. In addition, a motor provided in the image forming apparatus 1 that rotates only in one direction (in the above-described embodiment, a paper conveyance motor) can also be used as the drive motor 60 of the screw shaft 52. Therefore, it is not necessary to separately install a dedicated motor for driving the screw shaft 52 in the optical scanning device 4. Therefore, the optical scanning device 4 can be reduced in size and cost.

  In the above embodiment, the first spiral groove 52 a and the second spiral groove 52 b formed in the screw shaft 52 are formed over the entire axial direction of the screw shaft 52. The end of the first spiral groove 52 a and the end of the second spiral groove 52 b are connected at the end of the screw shaft 52. Therefore, the moving direction of the holding member 53 can be reliably reversed at the end of the screw shaft 52 in the axial direction.

  In the above embodiment, the absolute value of the lead angle of the first spiral groove 52a is set equal to the absolute value of the lead angle of the second spiral groove. Thereby, the moving speed can be made equal between the forward movement and the backward movement of the holding member 53. Therefore, the cleaning member 51 can reliably clean the surface of the dust-proof glass 46 at a constant speed.

<< Other embodiments >>
In the above embodiment, the lead angle of the first spiral groove 52a and the lead angle of the second spiral groove 52b are set to be the same, but both angles may be made different. Thereby, the moving speed can be made different between the forward movement and the backward movement of the holding member 53. Therefore, for example, the cleaning time of the dust-proof glass 46 by the automatic cleaning mechanism 50 can be shortened by increasing the moving speed at the backward operation than the moving speed at the forward operation of the holding member 53.

  As described above, the present invention is useful for the cleaning mechanism for the cover of the optical scanning device and the optical scanning device provided with the cleaning mechanism.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 4 Optical scanning device 40 Housing 45 Outlet port 46 Dust-proof glass 50 Automatic cleaning mechanism 51 Cleaning member 52 Screw shaft 52a First spiral groove 52b Second spiral groove 53 Holding member 53d First spiral protrusion (first protrusion)
53e Second spiral protrusion (second protrusion)

Claims (4)

A cleaning mechanism for the transparent cover portion of an optical scanning device having a housing in which a light exit port is formed and a transparent cover portion for closing the exit port,
A rotatable screw shaft disposed along the transparent cover portion and having a spiral groove formed on the peripheral surface thereof;
An engaging portion that engages with the groove portion of the screw shaft, and a holding member configured to move along the screw shaft by rotating the screw shaft;
A cleaning member that is held by the holding member and cleans the surface of the transparent cover part by moving the holding member;
The groove part includes a first spiral groove and a second spiral groove whose lead angles are opposite to each other and intersect each other,
The said engaging part is a cleaning mechanism containing the 1st projection part engaged with the said 1st spiral groove, and the 2nd projection part engaged with the said 2nd spiral groove. The cleaning mechanism according to claim 1,
Each of the first spiral groove and the second spiral groove is formed over the entire axial direction of the screw shaft,
The cleaning mechanism in which the end of the first spiral groove and the end of the second spiral groove are connected to each other at the end of the screw shaft. The cleaning mechanism according to claim 1 or 2,
The cleaning mechanism, wherein the absolute value of the lead angle of the first spiral groove is equal to the absolute value of the lead angle of the second spiral groove. An optical scanning device having the cleaning mechanism according to claim 1.

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