JP5033097B2 - Automatic cleaning mechanism, optical scanning apparatus and image forming apparatus having the same - Google Patents

Description

  The present invention relates to an automatic cleaning mechanism for automatically cleaning a dust-proof glass covering an emission port of light emitted from a scanning optical system, and an optical scanning device and an image forming apparatus provided with the automatic cleaning mechanism.

  In an image forming apparatus such as a copying machine or a printer that forms an image on a sheet by electrophotography, a latent image is written from an optical scanning device to an image carrier such as a photosensitive drum whose surface is uniformly charged by charging means. A latent image is formed on the image carrier by irradiating light, and the latent image is developed with toner as a developer by a developing device to be visualized as a toner image.

  Here, the optical device is configured by housing a scanning optical system that emits light for writing a latent image to the image carrier in a frame, and an emission port of light emitted from the scanning optical system in the frame. The exit is covered with a transparent dustproof glass.

  In such an optical device, when dirt or dust adheres to the surface of the dust-proof glass, the optical characteristics deteriorate. Therefore, it is necessary to periodically clean the surface of the dust-proof glass, and an automatic cleaning mechanism has been proposed.

For example, in Patent Document 1, a cleaning unit that cleans dust-proof glass includes a pad-shaped cleaning unit and a holding unit that holds the cleaning unit, and the holding unit is rotatably joined to the cleaning unit. Thus, dust-cleaning glass cleaning means has been proposed that makes the pressure distribution during cleaning constant.
JP 2005-246901 A

  By the way, in cleaning the dust-proof glass of the optical scanning device, the contact pressure of the cleaning member to the dust-proof glass is an important factor in the cleaning performance, and in order to properly manage the contact pressure, the accuracy of the parts is increased or the cleaning performance is improved. It is necessary to design with a certain degree of freedom.

  However, increasing the component accuracy increases the manufacturing cost, and it becomes difficult to maintain a high cleaning performance at all times if the design has a degree of freedom in the cleaning performance.

  Further, in the conventional automatic cleaning mechanism, the contact pressure of the cleaning member cannot be arbitrarily adjusted during use, and when the cleaning member is deteriorated, the cleaning member can be easily replaced with a new one. could not.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is an automatic cleaning mechanism that can adjust the contact pressure of the cleaning member during use and can easily replace the cleaning member. And providing an optical scanning device and an image forming apparatus including the same.

  In order to achieve the above object, the invention according to claim 1 is characterized in that a scanning optical system that emits light for writing a latent image to the image carrier is accommodated in a frame, and the light emitted from the scanning optical system is received. A mechanism provided in an optical scanning device in which an exit port is covered with dustproof glass, wherein a holding member holding a cleaning member is movably supported, and the dustproof glass is moved by moving the cleaning member along the dustproof glass. In the automatic cleaning mechanism that automatically cleans the glass, the holding portion of the holding member that holds the cleaning member is configured to be foldable, and the cleaning member is sandwiched by the holding portion.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, protrusions are respectively provided on two surfaces of the holding portion that sandwich the cleaning member.

  According to a third aspect of the present invention, in the second aspect of the present invention, the protrusions are alternately provided on two opposing clamping surfaces of the holding portion.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the holding member is composed of a first member holding the cleaning member and a movable second member. The first member is detachably attached to the second member.

  According to a fifth aspect of the present invention, a scanning optical system that emits light for writing a latent image to the image carrier is accommodated in a frame, and an emission port of the light emitted from the scanning optical system is covered with dust-proof glass. An optical scanning device comprising the automatic cleaning mechanism according to any one of claims 1 to 4.

  An image forming apparatus according to a sixth aspect includes the optical scanning device according to the fifth aspect.

  According to the first aspect of the present invention, since the cleaning member is sandwiched by the foldable holding portion of the holding member, the holding position of the cleaning member with respect to the holding member is changed during use to adjust the free end thereof. Therefore, the contact pressure of the cleaning member to the dust-proof glass can be easily adjusted, and as a result, high cleaning performance can always be ensured. Moreover, since the cleaning member can be attached to and detached from the holding member, when the cleaning member is deteriorated, it can be easily replaced with a new one.

  According to the second aspect of the present invention, the cleaning member can be reliably held by the protrusions provided on the opposing holding surfaces of the holding portion, and the falling of the cleaning member from the holding member can be reliably prevented. it can.

  According to the third aspect of the present invention, the cleaning member is more reliably held by the protrusions alternately projecting from the holding surfaces facing each other of the holding portion, and the drop-off from the holding member is reliably prevented.

  According to the fourth aspect of the present invention, the holding member is divided into the first member and the second member, and the first member holding the cleaning member is attached to and detached from the second member threadedly inserted into the screw shaft. Since the mounting is possible, it is not necessary to remove the second member from the screw shaft when replacing the cleaning member, and the first member is left with respect to the second member while leaving the second member on the screw shaft. The cleaning member can be easily replaced by attaching and detaching.

  According to the fifth and sixth aspects of the invention, the effects of the first to fourth aspects of the invention can be obtained in the optical scanning device.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  First, an image forming apparatus according to the present invention will be described below with reference to FIG.

  FIG. 1 is a cross-sectional view of a color laser printer as an embodiment of an image forming apparatus according to the present invention. The illustrated color laser printer is a tandem type, and a magenta image forming unit is provided at the center of the main body 100. 1M, a cyan image forming unit 1C, a yellow image forming unit 1Y, and a black image forming unit 1K are arranged in tandem at regular intervals.

  Each of the image forming units 1M, 1C, 1Y, and 1K is provided with photosensitive drums 2a, 2b, 2c, and 2d, which are image carriers, and a charger 3a is disposed around each of the photosensitive drums 2a to 2d. 3b, 3c, 3d, developing devices 4a, 4b, 4c, 4d, transfer rollers 5a, 5b, 5c, 5d and drum cleaning devices 6a, 6b, 6c, 6d, respectively.

  Here, the photosensitive drums 2a to 2d are drum-shaped photosensitive members, and are driven to rotate at a predetermined process speed in a direction indicated by an arrow (clockwise) by a driving motor (not shown). The chargers 3a to 3d uniformly charge the surfaces of the photosensitive drums 2a to 2d to a predetermined potential by a charging bias applied from a charging bias power source (not shown).

  Further, the developing devices 4a to 4d contain magenta (M) toner, cyan (C) toner, yellow (Y) toner, and black (K) toner, respectively, and are formed on the photosensitive drums 2a to 2d. In addition, the toner of each color is attached to each electrostatic latent image to visualize each electrostatic latent image as a toner image of each color.

  The transfer rollers 5a to 5d are arranged so as to be in contact with the photosensitive drums 2a to 2d via an intermediate transfer belt 7 'at each primary transfer portion. Here, the intermediate transfer belt 7 ′ is stretched between the secondary transfer counter roller 8 ′ and the tension roller 9 ′ and is disposed on the upper surface side of each of the photosensitive drums 2 a to 2 d. The secondary transfer counter roller 8 ′ is disposed so as to be in contact with the secondary transfer roller 10 ′ via the intermediate transfer belt 7 ′ in the secondary transfer portion. A belt cleaning device 11 'is provided in the vicinity of the tension roller 9'.

  Incidentally, toner containers 12a, 12b, 12c, and 12d for supplying toner to the developing devices 4a to 4d are arranged in a line above the image forming units 1M, 1C, 1Y, and 1K in the apparatus main body 100. It is installed.

  Further, an optical scanning device (laser scanner unit) 1 ′ according to the present invention is disposed below the image forming units 1M, 1C, 1Y, and 1K in the apparatus main body 100, and the bottom of the main body 100 below the main body 100 is supplied. A paper cassette 14 'is detachably installed. A plurality of sheets of paper (not shown) are stacked and accommodated in the paper feed cassette 14 ′. A pickup roller 15 ′ for picking up paper from the paper feed cassette 14 ′ and a take-out roller are taken out near the paper feed cassette 14 ′. A feed roller 16 'and a retard roller 17' are provided for separating the separated sheets and feeding them one by one to the conveyance path L.

  In addition, the conveyance path L extending in the vertical direction on the side of the apparatus main body 100 includes a conveyance roller pair 18 ′ that conveys a sheet and the secondary transfer counter roller 8 ′ at a predetermined timing after the sheet is temporarily held. A pair of registration rollers 19 ′ is provided to be supplied to the secondary transfer portion which is a contact portion between the secondary transfer roller 10 ′ and the secondary transfer roller 10 ′. Next to the conveyance path L, another conveyance path L ′ used for forming an image on both sides of the sheet is formed. In this conveyance path L ′, a plurality of reversing roller pairs 20 ′ are provided. They are provided at appropriate intervals.

  By the way, the conveyance path L arranged in the vertical direction on one side of the apparatus main body 100 extends to a paper discharge tray 21 ′ provided on the upper surface of the apparatus main body 100, and in the middle thereof, the fixing device 22 ′. And a pair of paper discharge rollers 23 'and 24' are provided.

  Next, an image forming operation by the color laser printer having the above configuration will be described.

  When an image formation start signal is issued, the photosensitive drums 2a to 2d are driven to rotate at a predetermined process speed in the direction of the arrow (clockwise) in the image forming units 1M, 1C, 1Y, and 1K, and these photosensitive drums 2a. ˜2d are uniformly charged by the chargers 3a to 3d. The optical scanning device 1 emits a laser beam modulated by a color image signal for each color, irradiates the surface of each of the photosensitive drums 2a to 2d with each color on each of the photosensitive drums 2a to 2d. An electrostatic latent image corresponding to the color image signal is formed.

  First, magenta toner is attached to the electrostatic latent image formed on the photosensitive drum 2a of the magenta image forming unit 1M by the developing device 4a to which a developing bias having the same polarity as the charged polarity of the photosensitive drum 2a is applied. The electrostatic latent image is visualized as a magenta toner image. This magenta toner image is moved in the direction of the arrow in the figure by the action of the transfer roller 5a to which a primary transfer bias having a polarity opposite to that of the toner is applied in the primary transfer portion (transfer nip portion) between the photosensitive drum 2a and the transfer roller 5a. Primary transfer is performed on the intermediate transfer belt 7 ′ that is rotationally driven.

  The intermediate transfer belt 7 'on which the magenta toner image has been primarily transferred as described above moves to the next cyan image forming unit 1C. In the cyan image forming unit 1C as well, the cyan toner image formed on the photosensitive drum 2b is transferred onto the magenta toner image on the intermediate transfer belt 7 'at the primary transfer portion in the same manner as described above.

  Similarly, yellow and black formed on the respective photosensitive drums 2c and 2d of the yellow and black image forming units 1Y and 1K on the magenta and cyan toner images superimposed and transferred onto the intermediate transfer belt 7 ′. The toner images are sequentially superimposed on each primary transfer portion, and a full-color toner image is formed on the intermediate transfer belt 7 ′. The transfer residual toner that is not transferred onto the intermediate transfer belt 7 ′ but remains on the photosensitive drums 2a to 2d is removed by the drum cleaning devices 6a to 6d, and the photosensitive drums 2a to 2d are used for the next image formation. Provided.

  Then, in accordance with the timing at which the front end of the full color toner image on the intermediate transfer belt 7 ′ reaches the secondary transfer portion (transfer nip portion) between the secondary transfer counter roller 8 ′ and the secondary transfer roller 10 ′, the paper feed cassette The sheet fed from 14 'to the conveyance path L by the pickup roller 15', the feed roller 16 'and the retard roller 17' is conveyed to the secondary transfer section by the registration roller pair 19 '. Then, a full-color toner image is collectively transferred from the intermediate transfer belt 7 ′ to the sheet conveyed to the secondary transfer unit by the secondary transfer roller 10 ′ to which a secondary transfer bias having a polarity opposite to that of the toner is applied. Is done.

  Thus, the sheet on which the full-color toner image has been transferred is conveyed to the fixing device 22 ', where the full-color toner image is heated and pressurized and thermally fixed on the surface of the sheet, and the toner image is fixed. Are discharged onto the discharge tray 21 'by the discharge roller pair 23', 24 ', and a series of image forming operations is completed. The transfer residual toner that is not transferred onto the sheet and remains on the intermediate transfer belt 7 'is removed by the belt cleaning device 11', and the intermediate transfer belt 7 'is prepared for the next image formation.

  Next, the optical scanning device 1 according to the present invention will be described.

  2 is a perspective view of the optical scanning device according to the present invention, FIG. 3 is an enlarged detail view of part A of FIG. 2, FIG. 4 is a side view of the optical scanning device, FIG. 5 is a plan view of the optical scanning device, and FIG. 5 is a sectional view taken along the line BB in FIG. 5, FIG. 7 is an enlarged detail view of a portion C in FIG. 6, FIG. 8 is a sectional view taken along the line DD in FIG. Is a perspective view of the holding member (first member) and the cleaning pad held by the holding member, FIG. 11 is a sectional view taken along line FF in FIG. 10, and FIG. 12 is a state in which the holding member (first member) is opened. It is a perspective view shown.

  An optical scanning device 1 shown in FIG. 2 is a laser scanner unit (LSU) provided in the color laser printer shown in FIG. 1, and two photosensitive drums are included in a rectangular box-shaped frame 2 (not shown). On the other hand, two scanning optical systems for emitting laser light for writing a latent image are provided side by side. The laser scanner unit 1 according to this embodiment is for a color image forming apparatus, and two sets of such laser scanner units 1 are provided in the main body of the color image forming apparatus.

  The cover 3 that covers the upper surface of the frame 2 of the laser scanner unit 1 is formed with two rectangular elongated exit ports (not shown) through which the laser beams respectively emitted from the two scanning optical systems pass. These exit openings are covered with a transparent elongated dustproof glass 4 that transmits light. Here, each exit port and the dust-proof glass 4 covering the exit port have a rectangular shape that is long in the main scanning direction (the left-right direction in FIG. 5) of the laser light with respect to each photosensitive drum, and the surface of each dust-proof glass 4 is the present invention. It is cleaned by the automatic cleaning mechanism 5 according to the above.

  Next, the configuration of the automatic cleaning mechanism 5 according to the present invention will be described.

  As shown in FIG. 1, the laser scanner unit 1 according to the present embodiment is provided with a pair of automatic cleaning mechanisms 5 for two dustproof glasses 4, and the two dustproof glasses 4 are automatically cleaned. 1 and is simultaneously and automatically cleaned.

  The automatic cleaning mechanism 5 includes a screw shaft 6 that is rotationally driven by a drive motor (not shown) and a gear train provided on one side of the frame 2 (the right side in FIGS. 5 and 6), and a screw that is screwed onto the screw shaft 6. The holding member 7 to be inserted and the cleaning pad 8 (see FIGS. 3 and 7), which is a cleaning member held at both ends of the holding member 7, are configured. A drive motor that can rotate forward and backward is used. A driving gear 9 is attached to one end of the screw shaft 6 on the driving side.

  Thus, as shown in FIGS. 3 and 7 to 9, the holding member 7 is inserted into the first member 7 </ b> A for holding the cleaning pad 8 and the second screw threadably inserted into the screw shaft 6. The first member 7A is detachably attached to both end portions of the second member 7B. Here, the first and second members 7A and 7B are made of resin, and are screwed into the screw shaft 6 at the center in the width direction of the second member 7B as shown in FIGS. A boss portion 7a is formed, and from this boss portion 7a, an arm portion 7b extends integrally in the left and right (sub-scanning direction orthogonal to the main scanning direction of the laser beam), and a first portion is formed at the end of each arm portion 7b. The member 7A is detachably mounted. Further, an operation return spring 10 is penetratingly held in one arm portion 7b of the second member 7B in the moving direction of the holding member 7 (left and right direction in FIG. 5).

  The first member 7A can be folded around the folding line L as shown in FIG. 12, and hinges 7c are formed at both ends in the longitudinal direction along the folding line L as shown in FIG. ing. As shown in FIG. 10, the first member 7A is folded around the hinge portion 7c, and the two holding pieces 7A1 and 7A2 divided with the fold line L as a boundary include the cleaning pad 8 therebetween. Hold it with a pinch. In addition, as a material of the cleaning pad 8, silicon rubber or urethane rubber is selected.

  Engaging claws 7d and 7e are formed at both ends in the longitudinal direction of the holding pieces 7A1 and 7A2 of the first member 7A, respectively. These engaging claws 7d and 7e connect the first member 7A. As shown in FIG. 10, the two holding pieces 7A1 and 7A2 are joined and integrated with each other when they are folded.

  In addition, an engaging projection 7f is provided at the center in the width direction of the outer surface of each holding piece 7A1, 7A2 of the first member 7A, and as shown in FIGS. 11 and 12, the inner surface of one holding piece 7A1 (that is, the holding piece 7A1). A positioning projection 7g is integrally projected at the center in the width direction of the sandwiching surface between which the cleaning pad 8 is sandwiched, and two projections 7h extending in the width direction are projected in parallel with each other. Two protrusions 7i extending in the width direction are also provided in parallel with each other on the inner surface of the other holding piece 7A2 of the first holding member 7A, and are provided on the inner surfaces of these protrusions 7i and the holding piece 7A1. As shown in FIG. 11, the protrusions 7h are alternately arranged in the vertical direction in a state where the holding pads 7A1 and 7A2 are joined with the cleaning pad 8 sandwiched between the holding pieces 7A1 and 7A2. 7i, the cleaning pad 8 is securely clamped and held by the first member 7A.

  Thus, when the cleaning pad 8 is attached to the first member 7A, both the holding pieces 7A1 are in a state in which the first member 7A is bent along the folding line L (see FIG. 12) around the hinge 7c. , 7A2, the cleaning pad 8 is inserted from the bottom until the upper end of the cleaning pad 8 comes into contact with the positioning projection 7g projecting from the holding surface (inner surface) of one holding piece 7A1, and then temporarily held. , 7A2 are engaged with each other by engaging claws 7d, 7e formed at both ends in the width direction, and the holding pieces 7A1, 7A2 are joined and integrated. Then, the cleaning pad 8 is held by the first member 7A with its both surfaces being clamped by the alternating projections 7h and 7i protruding from the clamping surfaces (inner surfaces) of the holding pieces 7A1 and 7A2.

  On the other hand, as shown in FIGS. 7 and 9, rectangular engagement holes 7j (only one is shown in the drawing) are provided at the ends of the left and right arm portions 7b of the second member 7B. As described above, the first member 7A holding the cleaning pad 8 is inserted and fitted into each engagement hole 7j. When the first member 7 </ b> A is thus attached to the second member 7 </ b> B, the cleaning pad 8 is held at a position where the lower end edge contacts the surface of the dust-proof glass 4.

  Thus, during the image forming operation by the image forming apparatus, the latent image writing laser beam emitted from the scanning optical system of the laser scanner unit 1 scans the photosensitive drum, thereby electrostatically forming the electrostatic drum on each photosensitive drum. A latent image is formed. The electrostatic latent image is developed with toner by a developing device (not shown) to be visualized as a toner image, and thereafter an image is formed on a sheet through a predetermined process such as transfer and fixing. .

  By the way, when the image forming operation is repeated, there arises a problem that the optical characteristics are gradually deteriorated because dirt and dust adhere to the surface of the dust-proof glass 4 of the laser scanner unit 1. For this reason, the surface of each dustproof glass 4 is automatically cleaned by the automatic cleaning device 5 according to the present invention.

  That is, when a drive motor (not shown) is driven and the driving force is input from a gear train (not shown) to the drive gear 9 at the end of the screw shaft 6, the screw shaft 6 is rotationally driven and screwed onto the screw shaft 6. Since the holding member 7 to be inserted and the cleaning pad 8 held at both ends of the holding member 7 move in the main scanning direction of the laser beam, the cleaning pad 8 rubs the surface of the dust-proof glass 4 and the surface of the dust-proof glass 4 The dust-proof glass 4 is cleaned by removing dirt and dust adhering to the surface.

  When the holding member 7 and the cleaning pad 8 reach the standby position where the movement limit is reached, the drive motor is reversed to move the holding member 7 and the cleaning pad 8 in the opposite directions, and the surface of each dustproof glass 4 is the cleaning pad 8. Is rubbed and cleaned. Thereafter, the same operation is repeated, and the surface of each dustproof glass 4 is cleaned by the reciprocating cleaning pad 8, so that the optical characteristics of the laser scanner unit 1 are prevented from deteriorating due to dirt on the dustproof glass 4.

  As described above, in the present embodiment, the cleaning pad 8 is held by the foldable holding pieces 7A1 and 7A2 of the first member 7A of the holding member 7, so that the cleaning pad 8 is held by the holding member 7 during use. By changing the position and adjusting its free end, the contact pressure of the cleaning pad 8 to the dust-proof glass 4 can be easily adjusted. As a result, high cleaning performance can always be ensured.

  Moreover, since the cleaning pad 8 can be attached to and detached from the holding member 7, when the cleaning pad 8 is deteriorated, it can be easily replaced with a new one.

  Further, in the present embodiment, the holding member 7 is divided into two parts, a first member 7A and a second member 7B, and the first member 7A holding the cleaning pad 8 is screwed through the screw shaft 6. Since the second member 7B does not need to be removed from the screw shaft 6 when the cleaning pad 8 is replaced, the second member 7B remains on the screw shaft 6 without being removed. The cleaning pad 8 can be easily replaced by attaching / detaching the first member 7A to / from the second member 7B.

  Further, since the projections 7h and 7i formed on the opposing clamping surfaces (inner surfaces) of the holding pieces 7A1 and 7A2 of the first member 7A are arranged alternately as shown in FIG. 11, the projections 7h and 7i are used for cleaning. The pad 8 is more reliably held, and the drop-off from the first member 7A is surely prevented, and a stable cleaning operation is possible.

  Although the present invention has been described with respect to an embodiment in which the present invention is applied to an optical scanning device provided in a color image forming apparatus and an automatic cleaning mechanism provided therein, the present invention is directed to an optical scanning provided in a monochrome image forming apparatus. Of course, the present invention can be similarly applied to the apparatus and the automatic cleaning mechanism provided therein.

1 is a cross-sectional view of a color laser printer according to the present invention. 1 is a perspective view of an optical scanning device according to the present invention. FIG. 3 is an enlarged detail view of a part A in FIG. 2. It is a side view of the optical scanning device concerning the present invention. It is a top view of the optical scanning device concerning the present invention. FIG. 6 is a sectional view taken along line B-B in FIG. 5. It is the C section enlarged detail drawing of FIG. It is the DD sectional view taken on the line of FIG. It is the E section expansion perspective view of FIG. It is a perspective view of a holding member (first member) and a cleaning pad held by the holding member. It is the FF sectional view taken on the line of FIG. It is a perspective view which shows the state which opened the holding member (1st member).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical scanning device 2 Frame 3 Cover 4 Dust-proof glass 5 Automatic cleaning mechanism 6 Screw shaft 7 Holding member 7A First member of holding member 7A1, 7A2 Holding piece 7B of first member 7B Second member of holding member 7a Second Boss portion 7b Second member arm portion 7c First member hinge portion 7d, 7e First member engagement claw 7f First member engagement projection 7g First member positioning projection 7h 7i Projection of first member 7j Engagement hole of second member 8 Cleaning pad (cleaning member)
9 Drive gear 10 Spring for operation return L Folding line

Claims (6)

A scanning optical system that emits light for writing a latent image to the image carrier is housed in a frame, and is provided in an optical scanning device in which a light exit exiting from the scanning optical system is covered with dust-proof glass. In an automatic cleaning mechanism that supports a movably holding member that holds a cleaning member and automatically cleans the dust-proof glass by moving the cleaning member along the dust-proof glass,
An automatic cleaning mechanism, wherein a holding portion for holding the cleaning member of the holding member is configured to be foldable, and the cleaning member is sandwiched by the holding portion.   The automatic cleaning mechanism according to claim 1, wherein protrusions are respectively provided on two surfaces of the holding portion that sandwich the cleaning member.   The automatic cleaning device according to claim 2, wherein the protrusions are alternately provided on the two surfaces of the holding portion.   The holding member includes a first member that holds the cleaning member and a movable second member, and the first member is detachably mounted on the second member. The automatic cleaning device according to any one of claims 1 to 3. An apparatus comprising: a scanning optical system that emits light for writing a latent image to an image carrier; and a light exit port that emits light from the scanning optical system covered with dust-proof glass.
An optical scanning device comprising the automatic cleaning mechanism according to claim 1. An image forming apparatus comprising the optical scanning device according to claim 5.

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