JP2007121586A - Optical scanner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively provide an optical scanner in a simple manner in which the shift of the positional relation between a deflecting apparatus and an optical system is easily adjustable and the heat release effect of a polygon motor is enhanced. <P>SOLUTION: The deflecting apparatus 21 is constituted of: a mirror driving part 25 composed of the polygon motor 17 and a circuit board 18; a polygon mirror 34; and a dust cover 22 or the like. An open part 6 which is smaller than a deflecting apparatus mounting plate 3 and is sized to penetrate the deflecting apparatus 21 therethrough is formed on the housing part 16a of the optical scanner 20, the deflecting apparatus mounting plate 3 is fixed from the outside of the housing part 16a with six machine screws 5a so as to block the open part 6, and the circuit board 18 is fixed on the deflecting apparatus mounting plate 3 with four machine screws 5b via the open part 6 from the inside of the housing part 16a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical scanning device that scans a surface to be scanned with light beams, and more particularly to position adjustment and cooling of a deflecting device that deflects light beams.

  An optical scanning device that rotates a polygon mirror with a motor and irradiates a reflection surface provided on the side surface of the polygon with a laser beam to scan the reflection light is used in an image forming apparatus such as a copying machine or a laser printer. Yes. The configuration of such an optical scanning device will be described with reference to FIG.

  In FIG. 9, reference numeral 30 denotes a light source unit having a laser diode (hereinafter referred to as LD) as a light source, and emits a light beam (laser light) light-modulated based on an image signal. Reference numeral 31 denotes a collimator lens, which converts the light beam emitted from the light source unit 30 into a substantially parallel light beam. Reference numeral 32 denotes an aperture for limiting the optical path width of the beam light that has passed through the collimator lens 31. Reference numeral 33 denotes a cylindrical lens having a predetermined refractive power only in the sub-scanning direction.

  Reference numeral 34 denotes a polygon mirror as a deflecting unit, which is composed of a regular hexagonal rotary polygon mirror having six deflecting surfaces (reflecting surfaces) on the side surface, and is driven in the direction of arrow A by a driving unit (not shown) such as a motor. Is rotating at a predetermined speed. Reference numeral 35 denotes a scanning lens having an fθ characteristic, and the beam light deflected and reflected by the polygon mirror 34 is imaged on the photosensitive drum 100. Reference numeral 36 denotes a folding mirror that changes the optical path of the beam light that has passed through the scanning lens 35 in the direction of the photosensitive drum 100.

  The photosensitive drum 100 is rotated at a predetermined speed in the sub-scanning direction (arrow C direction) by a driving unit (not shown) such as a motor, and image information is received by beam light that forms an image on the photosensitive drum 100. Written as a latent image. Around the photosensitive drum 100, a charging unit, a developing unit, a transfer unit, and the like (all not shown) are disposed as electrophotographic process means.

  In this example, the beam light emitted from the light source unit 30 is made into a substantially parallel light beam by the collimator lens 31, and the light beam that has become a substantially parallel light beam is made into a predetermined optical path width by the aperture 32, and then has a refractive power only in the sub-scanning direction. Is incident on a cylindrical lens 33. The parallel light beam incident on the cylindrical lens 33 is in the state of a parallel light beam as it is in the main scanning section, converged and emitted in the sub-scanning direction, and formed as a line image on the deflection surface (reflection surface) of the polygon mirror 34. ing.

  The beam light deflected and reflected by the polygon mirror 34 is guided (imaged) onto the photosensitive drum 100 via the scanning lens 35 and the folding mirror 36, and has a spot diameter of a predetermined size on the photosensitive drum 100. Is forming. Then, by rotating the polygon mirror 34 in the direction of arrow A in the figure, the image data is recorded by optically scanning the photosensitive drum 100 in the main scanning direction (arrow B direction).

  Inside an image forming apparatus using an electrophotographic process. Toner used for developing the electrostatic latent image, paper dust generated by transporting the paper, dust entering from the outside of the image forming apparatus, etc. are scattered and floating. If these dusts enter the optical device and adhere to optical elements and optical members such as lenses and mirrors, a part of the optical path of the scanning light is blocked, which causes a reduction in image quality. For this reason, measures have been taken to improve the sealing performance of the optical device and prevent dust from entering from the outside.

  On the other hand, with the recent increase in speed and resolution of image forming apparatuses, there has been an increasing demand for high-speed rotation of a motor that rotates a polygon mirror, which is a deflection apparatus of a scanning system. As the motor speed increases as described above, the necessity of radiating heat generated by the rotation of the motor rotor and heat generated from the circuit board that controls the motor rotation is increasing. However, heat treatment is difficult with a highly confidential optical device, and it is necessary to design an open system. However, a sealed system is preferable for the dust countermeasure described above, and the optical apparatus has both a heat generation countermeasure and a dust countermeasure. Design has become an important issue.

  Therefore, in Patent Document 1, as shown in FIG. 10, by using materials having different thermal conductivities for the polygon motor fixing portion and the optical system fixing portion on the bottom surface of the housing, the optical scanning device is not increased in size. An optical scanning device that improves heat dissipation efficiency is disclosed. In FIG. 10, only the configuration in the vicinity of the deflecting device which is a part of the optical scanning device is shown.

  Reference numeral 17 denotes a polygon motor that rotates the polygon mirror 34, and 18 denotes a circuit board that controls driving of the polygon motor 17. The polygon motor 17 is fixed so as to penetrate the circuit board 18. The polygon motor 17 and the circuit board 18 constitute a mirror driving unit 25 that drives the polygon mirror 34. The housing of the optical scanning device 20 is configured so that the internal sealing is maintained by the housing portion 16a and the cover portion 16b, and prevents intrusion of dust and the like from the outside.

  In the housing portion 16a, a metal plate 16aa to which the mirror driving portion 25 is fixed by a screw 19 and a resin portion 16ab to which the scanning lens 35 and the like are fixed are integrally formed. With this configuration, the heat generated by the polygon motor 17 is transmitted to the metal plate 16aa and effectively radiated to the outside of the housing.

However, in the method of Patent Document 1, when dimensional variations occur in the housing portion 16a and the mirror driving portion 25, for example, a dimension adjusting member such as a spacer or a washer is disposed between the metal plate 16aa and the circuit board 18. Thus, it is possible to adjust the polygon mirror 34 upward, but the polygon mirror 34 cannot be adjusted downward, and the height of the polygon mirror 34 can be easily adjusted in an arbitrary direction. It was difficult. Furthermore, since the polygon motor fixing part and the optical system fixing part are integrally formed using different materials, the structure of the housing becomes complicated and disadvantageous in terms of cost, and separation and recycling at the time of disposal of the device becomes difficult. Also, it was not preferable for environmental measures.
Patent No. 3075497

  In view of the above problems, the present invention provides a simple and low-cost optical scanning device that can easily adjust the positional relationship between the deflecting device and another optical system and that also enhances the heat dissipation effect of the polygon motor. With the goal.

  In order to achieve the above object, the present invention provides a deflecting device comprising a regular polygonal mirror whose side surface is constituted by a mirror and a mirror driving unit for rotating the polygon mirror, a housing incorporating the deflecting device, A deflection device mounting plate that is fixed to the deflection device and forms a part of the housing; and an optical scanning device that deflects and scans a light beam by rotationally driving the polygon mirror. Is formed with an opening that is smaller than the deflecting device mounting plate and through which the deflecting device penetrates, and the deflecting device mounting plate is formed from the outside of the housing so as to close the opening. The deflecting device is fixed to the deflecting device mounting plate through the opening.

  According to the present invention, in the optical scanning device having the above-described configuration, the housing and the deflection device mounting plate, and the deflection device and the deflection device mounting plate are fixed by screws.

  According to the present invention, in the optical scanning device having the above-described configuration, the deflecting device mounting plate is formed of a material having higher thermal conductivity than other portions constituting the casing.

  According to the present invention, in the optical scanning device having the above configuration, a dimension adjusting member is disposed between the deflecting device and the deflecting device mounting plate.

  According to the present invention, in the optical scanning device having the above-described configuration, a dimension adjusting member is disposed between the housing and the deflecting device mounting plate.

  According to the first configuration of the present invention, since the deflecting device is fixed inside the deflecting device mounting plate, and the deflecting device mounting plate is fixed from the outside of the housing, between the deflecting device and the deflecting device mounting plate, Alternatively, by placing a dimension adjusting member between the housing and the deflection device mounting plate, the arrangement of the deflection device can be adjusted in any of the vertical directions, and the positional relationship between the deflection device and other optical members is easy. Can be adjusted. In addition, since the deflecting device mounting plate is made of a separate member, even when the deflecting device mounting plate is made of different materials, it is easy to separate and recycle when discarding the device, and is excellent in environmental friendliness. It becomes.

  According to the second configuration of the present invention, in the optical scanning device of the first configuration, the housing and the deflecting device mounting plate, and the deflecting device and the deflecting device mounting plate are fixed with screws, thereby performing the optical scanning. When assembling the device, the arrangement of the deflection devices can be finely adjusted one by one.

  Further, according to the third configuration of the present invention, in the optical scanning device having the first or second configuration, the deflecting device mounting plate is made of a material having a higher thermal conductivity than other portions constituting the casing. By forming, heat generated from the deflecting device can be efficiently released to the outside.

  Further, according to the fourth configuration of the present invention, in the optical scanning device having any one of the first to third configurations, by disposing the dimension adjusting member between the deflection device and the deflection device mounting plate, An optical scanning device in which the downward displacement and inclination of the deflecting device due to the dimensional tolerances of components and the like is adjusted is obtained.

  According to the fifth configuration of the present invention, in the optical scanning device having any one of the first to fourth configurations, by disposing the dimension adjusting member between the housing and the deflection device mounting plate, An optical scanning device in which the upward displacement and inclination of the deflecting device due to the dimensional tolerances of the components is adjusted is obtained.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic perspective view showing the configuration of the optical scanning device of the present invention, and FIG. 2 is a back view of the optical scanning device of the present invention. Portions common to FIG. 10 of the conventional example are denoted by the same reference numerals and description thereof is omitted. FIG. 1 shows a state where the cover portion 16b (see FIG. 10) is removed.

  In the housing portion 16a of the optical scanning device 20, a deflecting device 21, fθ lenses 35a and 35b, a folding mirror 36, and the like are arranged. The deflecting device 21 includes a polygon mirror 34, a polygon motor 17 (not shown), a circuit board 18, and the like. The polygon mirror 34 is sealed with a dustproof cover 22 to prevent adhesion of dirt such as dust. Here, the lid on the upper surface of the dust-proof cover 22 is removed so that the internal polygon mirror 34 can be seen.

  The beam light emitted from the light source unit 30 (see FIG. 9) is incident on the plane mirror 19 via an optical member such as a collimator lens 31, an aperture 32, and a cylindrical lens 33 (all of which refer to FIG. 9). Then, the light passes through the light entrance / exit window 23 provided in the dust cover 22 and enters the polygon mirror 34. The beam light deflected by the deflecting surface of the polygon mirror 34 passes through the light incident / exit window 23 again, and passes through the scanning lens 35 including the fθ lenses 35a and 35b and the folding mirror 36, and is connected to the surface to be scanned (not shown). Imaged. A window portion 24 is provided on the bottom surface of the housing portion 16a to guide the beam light toward the surface to be scanned.

  Denoted at 3 is a deflection device mounting plate to which the deflection device 21 is fixed, and the bottom surface 17a of the polygon motor 17 (see FIG. 10) is exposed to the outside through the opening hole 3a of the deflection device mounting plate 3. The deflecting device mounting plate 3 is fixed to the housing portion 16a by six screws 5a. In addition, when the heat radiation of the polygon motor 17 is not strongly required, the opening hole 3a may not be provided and the bottom surface 17a may not be exposed.

  FIG. 3 is a back view of the vicinity of the deflecting device that is a part of the optical scanning device of the present invention, and FIG. 4 is a side sectional view (cross section AA ′ in FIG. 3) showing the configuration near the deflecting device. The dust cover 22 is fixed to the circuit board 18, and a transparent flat plate made of glass or resin is fitted into the light incident / exit window 23. The housing portion 16 a is formed with an opening 6 that is smaller than the deflecting device mounting plate 3 and through which the deflecting device 21 penetrates. The deflecting device mounting plate 3 closes the opening 6. The circuit board 18 is fixed to the deflection device mounting plate 3 through the opening 6 with four screws 5b from the inside of the housing portion 16a.

  According to this configuration, the arrangement of the deflecting device 21 can be adjusted upward by sandwiching the dimension adjusting member in the gap between the circuit board 18 and the deflecting device mounting plate 3, and the housing portion 16a and the deflecting device mounting plate can be adjusted. 3, the arrangement of the deflecting device 21 can be adjusted downward. In addition, the tilt of the deflecting device 21 can be adjusted by changing the position and thickness of the dimension adjusting member. Accordingly, the positional relationship between the deflecting device 21 and other optical members such as the light source unit 30 and the scanning lens 34 can be easily adjusted.

  Further, since the deflecting device mounting plate 3 is formed of a separate member, even when the housing portion 16a and the deflecting device mounting plate 3 are formed using different materials, it becomes easy to separate and collect at the time of discarding the device. Recyclability is also improved. The material of the deflecting device mounting plate 3 is not particularly limited and can be formed using various materials such as a metal material and resin. The deflecting device mounting plate 3 is a heat radiating plate that radiates heat from the mirror driving unit 25. Therefore, it is preferable that the mirror driving unit 25 is formed of a metal having a high thermal conductivity such as aluminum so that the heat of the mirror driving unit 25 can be efficiently radiated to the outside.

  Here, in consideration of the assembly efficiency of the optical scanning device 20, the screw 5a is fastened from the outside to the inside of the housing portion 16a, and the screw 5b is fastened from the inside to the outside of the housing portion 16a. However, the fastening direction of the screws 5a and 5b can be arbitrarily set.

  Next, a method for adjusting the arrangement of the deflecting device using the dimension adjusting member will be described. FIG. 5 is a plan view and a cross-sectional view showing an example of a dimension adjusting member used in the present invention. As shown in FIG. 5, the dimension adjusting member 26 is a washer-like member having a round hole 26a opened in the center, and the screws 5a and 5b (see FIG. 4) pass through the round hole 26a. It is positioned at the fastening location 5b.

  The material of the dimension adjusting member 26 is not particularly limited, and various materials such as resin and metal can be used, but a resin film is preferably used from the viewpoint of manufacturing cost. Further, the thickness of the dimension adjusting member 26 can be arbitrarily set according to the vertical adjustment pitch of the deflecting device 21, but is usually set to about 0.1 mm.

  FIG. 6 is a cross-sectional view of the main part showing a case where the deflection device is adjusted upward using the dimension adjusting member. Hereinafter, the adjustment method will be described along the assembly procedure of the optical scanning device with reference to FIGS. 4 and 5. Here, only one of the fastening locations of the screw 5a and the screw 5b is illustrated, but the description is omitted because the same applies to other fastening locations. First, the deflection device 21 is assembled using the polygon mirror 34, the polygon motor 17, the circuit board 18, the dust cover 22, and the like.

  Then, the dimension adjusting member 26 is sandwiched between the circuit board 18 and the deflection device mounting plate 3 so that the round hole 26a overlaps the screw hole. Next, the circuit board 18 and the deflection device mounting plate 3 are fastened with the screws 5b, and finally the deflection device mounting plate 3 and the housing portion 16a are fastened with the screws 5a. As a result, the deflection device 21 is disposed above the housing portion 16 a by the thickness of the dimension adjusting member 26.

  FIG. 7 is a cross-sectional view of the main part showing a case where the deflection device is adjusted downward using the dimension adjusting member. First, as in the case of FIG. 6, the deflecting device 21 is assembled in advance, and the circuit board 18 and the deflecting device mounting plate 3 are fastened with the screws 5b. Next, the housing portion 16a and the deflection device mounting plate 3 are fastened with screws 5a. At this time, the dimension adjusting member 26 is overlapped with the screw hole in the gap between the housing portion 16a and the deflection device mounting plate 3. So as to sandwich. As a result, the deflection device 21 is disposed below the housing portion 16 a by the thickness of the dimension adjusting member 26.

  Here, the position adjustment in the vertical direction of the deflection device 21 is performed by sandwiching one dimension adjusting member 26. However, two or more dimension adjusting members 26 may be sandwiched depending on the adjustment amount. Further, when adjusting the entire deflection device 21 upward or downward, the same number of dimension adjusting members 26 may be sandwiched between all the fastening points of the screws 5a and 5b. When adjusting the inclination of the deflection device 21, The dimension adjusting member 26 may be sandwiched only in a part of the fastening locations of the screws 5a and 5b, or the number of the dimension adjusting members 26 may be changed depending on the fastening location.

  Further, the shape of the dimension adjusting member 26 shown in FIG. 5 is merely an example, and may be a shape other than a circle, for example. Further, the dimension adjusting member 26 can be sandwiched between portions other than the fastening portions of the screws 5a and 5b. In this case, the round hole 26a through which the screws 5a and 5b pass is not necessary.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention. For example, in the above embodiment, the circuit board 18 and the deflection device mounting plate 3 or the housing portion 16a and the deflection device mounting plate 3 are fixed using screws, but the adjustment amount is determined in advance during the assembly work. When a predetermined number of dimension adjusting members are sandwiched at a predetermined position, the fixing is not limited to screw fixing, and may be fixed using an adhesive, rivet, eyelet or the like. However, when finely adjusting the number of dimension adjusting members and the sandwiching position one by one, it is preferable to fix the number of dimension adjusting members 26 and the position with a screw that can be easily changed.

  Although only the configuration in which the polygon mirror 34 is covered with the dustproof cover 22 has been described here, the present invention can be applied to a configuration in which the dustproof cover 22 is not used as shown in FIG. . In this case, since the dustproof property of the optical scanning device 20 is required more strongly, it is preferable to seal the gap between the deflection device mounting plate 3 and the housing 16a with a sealing member 27 made of an elastic material.

  According to the present invention, a polygonal mirror having a regular polygon whose side surface is made of a mirror and a deflecting device including a mirror driving unit for rotating the polygon mirror, a housing incorporating the deflecting device, and the deflecting device are fixed. An optical scanning device that deflects and scans a light beam by rotationally driving a polygon mirror, and the housing is smaller than the deflection device mounting plate, and An opening having a size through which the deflecting device passes is formed, and the deflecting device mounting plate is fixed from the outside of the housing so as to close the opening, and the deflecting device is attached to the deflecting device mounting plate through the opening. Fixed to.

  As a result, the positional relationship between the deflecting device and other optical members can be easily adjusted by simply sandwiching the dimension adjusting member between the deflecting device and the deflecting device mounting plate or between the housing and the deflecting device mounting plate during assembly. An optical scanning device can be provided. In addition, since the deflecting device mounting plate is made of a separate member, even when the deflecting device mounting plate is made of different materials, it is easy to separate and recycle when discarding the device, and is excellent in environmental friendliness. It becomes.

  Further, since the housing and the deflecting device mounting plate and the deflecting device and the deflecting device mounting plate are fixed with screws, the arrangement of the deflecting devices can be finely adjusted one by one when assembling the optical scanning device. Furthermore, if the deflecting device mounting plate is made of a material having high thermal conductivity such as aluminum, the effect of the deflecting device mounting plate as a heat radiating plate can be enhanced to efficiently release the heat generated from the deflecting device to the outside. it can.

These are the perspective views which show the internal structure of the optical scanner of this invention. These are back views of the optical scanning device of the present invention. These are back views of the vicinity of the deflecting device which is a part of the optical scanning device of the present invention. These are side surface sectional drawings which show the structure of the deflection | deviation apparatus vicinity which is a part of optical scanning apparatus of this invention. These are the top view and sectional drawing which show an example of the dimension adjustment member used for this invention. These are principal part sectional drawings which show the case where a deflection | deviation apparatus is adjusted upwards using a dimension adjustment member. These are principal part sectional drawings which show the case where a deflection | deviation apparatus is adjusted upwards using a dimension adjustment member. These are side surface sectional drawings which show the other structural example of the optical scanning device of this invention. These are the schematic block diagrams of the conventional optical scanning device. These are side surface sectional drawings which show the structure of the deflection | deviation apparatus vicinity of the conventional optical scanning device.

Explanation of symbols

3 Deflector mounting plate 5a, 5b Screw 6 Open hole 16a Housing (housing)
16b Cover (housing)
DESCRIPTION OF SYMBOLS 17 Polygon motor 18 Circuit board 20 Optical scanning device 21 Deflection device 22 Dust-proof cover 25 Mirror drive part 26 Size adjustment member 34 Polygon mirror 35 Scan lens

Claims (5)

A deflecting device comprising a regular polygon mirror whose side surface is made of a mirror and a mirror driving unit for rotating the polygon mirror, a housing incorporating the deflecting device, the deflecting device being fixed and the housing A deflection device mounting plate constituting a part of
In an optical scanning device that deflects and scans a light beam by rotationally driving the polygon mirror,
The casing is formed with an opening that is smaller than the deflecting device mounting plate and through which the deflecting device passes, and the deflecting device mounting plate closes the opening. An optical scanning device fixed from the outside of the body, wherein the deflection device is fixed to the deflection device mounting plate via the opening.   The optical scanning device according to claim 1, wherein the housing and the deflection device mounting plate, and the deflection device and the deflection device mounting plate are fixed by screws.   3. The optical scanning device according to claim 1, wherein the deflecting device mounting plate is formed of a material having a higher thermal conductivity than other portions constituting the casing.   4. The optical scanning device according to claim 1, wherein a dimension adjusting member is disposed between the deflecting device and the deflecting device mounting plate.   5. The optical scanning device according to claim 1, wherein a dimension adjusting member is disposed between the housing and the deflecting device mounting plate.

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