JP2009014787A - Laser beam scanner, and adjustment apparatus and adjustment method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a laser beam apparatus in which the position of X-axis along the optical axis of a light source unit and rotational position around the optical axis of the light source unit can easily and accurately be adjusted, and to obtain an adjustment apparatus and an adjustment method therefor. <P>SOLUTION: In the laser beam apparatus, the light source unit 2 is arranged by determining X-axis position along the optical axis, Y-axis position along a main scanning direction, Z-axis position along a subscanning direction and the turning position around the optical axis. A projection 14 for clamp of a holder 11 is pinched by a pair of clamp heads 31, the arc-shaped outer peripheral face of the holder 11 is pressurized against a V-shaped groove part of a base, thus the Y-axis position and the Z-axis position are determined. Further, the X-position is adjusted by moving the clamp heads 31 in the X-axis direction, and the turning potion is adjusted by turning the clamp heads 31 around the optical axis. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a laser beam scanning device, and more particularly to a laser beam scanning device mounted for forming an electrostatic latent image on a photoreceptor in an image forming apparatus such as a copying machine, a printer, a facsimile, and the adjustment device and adjustment method thereof. About.

  In a laser beam scanning apparatus mounted on an image forming apparatus such as a copying machine, a printer, or a facsimile machine, the light source part is composed of a light emitting element (laser diode) and a condensing optical element (collimator lens and cylindrical lens). These elements are assembled into a holder to form a unit, and this light source unit is fixed on the base of the housing. This light source unit needs to be adjusted with respect to the focus shift on the surface of the photosensitive member and the collapse of the beam shape caused by positioning errors such as a deflector, a scanning lens, and an optical path folding mirror fixed to the housing independently of the light source unit. .

  In order to adjust the focus shift and the beam shape collapse, with the light source unit mounted on a pedestal, the X-axis position along the optical axis and the rotational position centered on the optical axis are accurately adjusted, and It is necessary to adjust efficiently. As a precondition for this adjustment, it is necessary to accurately position the light source unit at the Y-axis position along the main scanning direction and the Z-axis position along the sub-scanning direction.

  Conventionally, a laser beam is projected onto a CCD camera placed at the virtual position of the photoconductor with all optical elements built into the housing using a dedicated adjustment device, and the center of gravity and size of the laser beam are measured. However, the adjustment was performed while pressing the light source unit against the base. However, in this case, when the pressing of the light source unit is released and a fixing cover for the light source unit is newly attached, the pedestal is distorted and the optical performance is distorted.

Patent Document 1 describes that a holder for holding a light source unit is mounted on a V-groove of a pedestal, and that the protrusion of the holder is moved in the Y-axis direction with a tool to adjust the rotational position of the laser light emitting element. Yes. However, Patent Document 1 does not mention adjustment of the X-axis position of the light source unit, and it is unsolved to efficiently adjust the X-axis position and the rotation position of the light source unit with a simple device.
JP 2004-34608 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a laser beam scanning apparatus that can easily and accurately adjust the X-axis position along the optical axis of a light source unit and the rotational position about the optical axis, and an adjustment apparatus and adjustment method thereof. There is.

In order to achieve the above object, the first invention
A light source unit in which a light emitting element and a condensing optical element for condensing a beam emitted from the light emitting element are fixed to a holder;
A pedestal for positioning the holder by positioning an X-axis position along the optical axis, a Y-axis position along the main scanning direction, a Z-axis position along the sub-scanning direction, and a rotational position around the optical axis; ,
A laser beam scanning device comprising:
The holder has an outer peripheral surface having an arc shape centered on the optical axis, and a clamp protrusion protruding downward from the outer peripheral surface,
The pedestal has a V-groove shaped portion extending in the optical axis direction for placing the arc-shaped outer peripheral surface of the holder, and has a relief hole through which the projection for clamping is inserted,
A pair of positioning slopes having an angle with respect to the Y-axis-Z-axis plane are formed symmetrically in the X-axis direction on the lower part of the clamp projection protruding from the back surface of the pedestal,
It is characterized by.

The second invention is
An apparatus for adjusting a laser beam scanning apparatus according to the first invention,
A pair of clamp heads that contact the pair of positioning slopes formed on the clamp protrusion from the X-axis direction;
An X-axis direction adjusting mechanism for positioning the X-axis position by moving the clamp head in the X-axis direction;
A rotation adjusting mechanism for positioning the rotational position by rotating the clamp head around the optical axis;
It is provided with.

The third invention is
An adjustment method of the laser beam scanning apparatus according to the first invention,
Placing the outer peripheral surface of the holder in an arc shape on the V-groove portion of the pedestal, and projecting the clamping protrusion from the relief hole to the back surface of the pedestal;
A step of bringing a pair of clamp heads into contact with a pair of positioning slopes formed on the clamp protrusion from the X-axis direction, and positioning the holder in the Y-axis direction and the Z-axis direction;
Adjusting the position of the clamp head in the X-axis direction;
Rotating the clamp head around the optical axis to adjust the rotational position;
It is provided with.

  According to the present invention, the outer peripheral surface forming the arc shape of the holder is placed on the V-groove shape portion of the pedestal, the projection for clamping is protruded from the escape hole to the back surface of the pedestal, and a pair of clamps are placed on the positioning slope of the clamping projection. By contacting the head from the X-axis direction, the outer peripheral surface of the holder is pressed against the V-groove shape portion, and the holder is positioned in the Z-axis direction and the Y-axis direction by the V-groove shape portion. At this time, while monitoring the laser beam at the virtual position of the photosensitive member, the X-axis position is adjusted by moving the clamp head in the X-axis direction, and the rotational position around the optical axis is adjusted.

  Through the above steps, the light source unit can be adjusted easily and accurately. After the adjustment, the holder can be fixed without error by bonding the holder to the base. As the adhesive, a photocurable adhesive, particularly an ultraviolet curable adhesive can be suitably used.

  Embodiments of a laser beam scanning apparatus, an adjusting apparatus and an adjusting method according to the present invention will be described below with reference to the accompanying drawings.

(See the overall configuration, Fig. 1 and Fig. 2)
FIG. 1 shows an embodiment of a laser beam scanning apparatus according to the present invention. The laser beam scanning device 1 generally includes a light source unit 2, a polygon mirror 6, a scanning lens 7 (consisting of two lenses 7a and 7b), a window glass 8, and a housing for holding these members. 10.

  In the light source unit 2, a laser diode 3, a collimator lens 4 and a cylindrical lens 5 functioning as a condensing element are attached in advance to a holder 11 described below with a predetermined accuracy. The beam emitted from the laser diode 3 is divergent light, is collimated by the collimator lens 4, and enters the polygon mirror 6 in a state of being substantially condensed in the sub-scanning direction Z by the cylindrical lens 5.

  The beam incident on the polygon mirror 6 is deflected at a constant angular velocity in the main scanning direction Y, corrected for aberration by passing through the scanning lenses 7a and 7b, and formed on the photosensitive drum 40 through the window glass 8. . The photosensitive drum 40 is rotationally driven at a predetermined speed, and a two-dimensional image (electrostatic latent image) is formed by main scanning by the laser beam and sub-scanning by the rotation of the drum 40.

  The lower part of FIG. 2 shows the spot shape of the laser beam on each optical element and the photosensitive drum 40.

(An example of a light collecting element, see FIG. 3)
Instead of the collimator lens 4 and the cylindrical lens 5, the light source unit 2 may use a condensing optical element 9 (DOE: Diffractive Optical Element) shown in FIG. The optical element 9 has a function of making light emitted from the laser diode 3 substantially parallel light in the main scanning direction Y and condensing near the mirror surface of the polygon mirror 6 in the sub-scanning direction Z. . The optical element 9 is integrally formed of resin and has two reflecting surfaces S2 and S3 that do not have a rotational symmetry axis, and two transmitting surfaces S1 and S4 that may be diffraction surfaces. If the optical element 9 having a plurality of functions is used, a compact light source unit 2 can be configured. A specific configuration of such an optical element 9 is described in detail in JP-A-2002-287062. Hereinafter, in the description of the embodiments with reference to FIGS. 4 to 9, the light source unit 2 including the condensing optical element 9 is shown.

(Refer to the light source unit adjusting device and adjusting method, FIGS. 4 to 9)
As shown in FIGS. 4 and 5, the light source unit 2 fixes the laser diode 3 to the rear end surface 11a of the holder 11 having the beam transmission port 12 by press-fitting or the like through the heat radiating plate 3a. The above-described condensing optical element 9 is bonded and fixed to 11b.

  FIG. 6 illustrates the holder 11 and FIG. 7 illustrates the pedestal 20, both of which are formed of a resin material. The holder 11 has an outer peripheral surface 13 having an arc shape centered on the optical axis X on the lower surface side, and a clamp protrusion 14 protruding downward from the outer peripheral surface 13. On the other hand, the pedestal 20 is for holding the light source unit 2 and itself constitutes a part of the housing 10 or is fixed to the housing. The pedestal 20 has a V-groove-shaped portion 21 composed of a pair of inclined surfaces 21 a and 21 a extending in the optical axis direction X for placing the outer peripheral surface 13 of the holder 11, and an escape hole 22 through which the clamp protrusion 14 is inserted. have.

  The clamping projection 14 has a lower portion protruding from the back surface of the pedestal 20 and has a predetermined angle (for example, 45) with respect to the Y-axis-Z plane when the main scanning direction Y is the Y-axis and the sub-scanning direction Z is the Z-axis. A pair of positioning slopes 15 and 15 having (°) are formed symmetrically in the X-axis direction.

As shown in FIGS. 5 and 8, the adjustment device 30 includes clamp heads 31 and 31, a chuck mechanism 32, an X-axis direction adjustment mechanism 33, and a rotation adjustment mechanism 34. The clamp heads 31, 31 have arcuate portions 31 a that come into contact with the pair of positioning slopes 15, 15 formed on the clamp protrusion 14 from the X ₁ direction and the X ₂ direction. The chuck mechanism 32 moves the clamp heads 31, 31 in the X ₁ direction and the X ₂ direction, presses the inclined surface 15 with the arc-shaped portion 31 a, and holds the holder 11 with the clamp heads 31, 31.

  The X-axis direction adjusting mechanism 33 is a conventionally known precision position adjusting mechanism generally called an X stage. The rotation adjustment mechanism 34 is a conventionally known precision rotation position adjustment mechanism generally called a swivel stage or a gonio stage. The rotation center of the rotation adjusting mechanism 34 is set to the optical axis X of the light source unit 2.

  The position adjustment of the light source unit 2 is performed through the following steps. First, the light source unit 2 is prepared in which the laser diode 3 and the condensing optical element 9 are positioned and fixed to the holder 11 with high accuracy. The outer peripheral surface 13 of the holder 11 is placed on the V-groove-shaped portion 21 of the pedestal 20, and the clamp protrusion 14 is projected from the escape hole 22 to the back surface of the pedestal 20. At this time, the housing 10 incorporates optical elements such as the polygon mirror 6 and the scanning lens 7, and a CCD camera for monitoring is set at the virtual position of the photosensitive member.

Next, the chuck mechanism 32 is operated to move the pair of clamp heads 31, 31 in the X ₁ direction and the X ₂ direction, and sandwich the lower portion of the clamp protrusion 14. As a result, the arc-shaped portion 31 a abuts and presses against the positioning slope 15 of the clamp protrusion 14, and the holder 11 is urged downward together with the clamp protrusion 14. And the outer peripheral surface 13 of the holder 11 is press-contacted with the V-groove shape part 21 of the base 20, and the holder 11 is positioned in a Y-axis direction and a Z-axis direction. That is, the positioning of the light source unit 2 in the Y-axis direction and the Z-axis direction is performed by the outer peripheral surface 13 and the V-groove shape portion 21 having an arc shape.

  Next, the X-axis direction adjusting mechanism 33 is operated to move the clamp heads 31 and 31 in the X-axis direction, thereby adjusting the position of the holder 11 in the X-axis direction. At this time, the beam diameter of the laser beam is monitored by the CCD camera and adjusted in the X-axis direction so as to obtain a predetermined beam diameter.

  Further, the rotation adjusting mechanism 34 is operated to adjust the θx rotation position (see the arrow θx in FIG. 4) of the clamp heads 31 and 31 with the optical axis X as the center. Also at this time, the tilt of the laser beam is monitored by the CCD camera, and the θx rotation position is adjusted so that the tilt of the beam becomes normal.

  Through the above-described steps using the adjusting device 30, the position of the light source unit 2 in the X-axis direction (focus shift) and the θx rotation position (deformation of the beam shape) about the optical axis X can be easily and accurately performed. Can be adjusted well. Of course, the relief hole 22 formed in the pedestal 20 is of a size that does not interfere with the clamping projection 14 during adjustment.

  When the above adjustment is completed, the holder 11 is bonded to the base 20. For this bonding, a photo-curing adhesive (preferably using an ultraviolet-curing type) is applied to a predetermined portion of the holder 11 or the pedestal 20 and cured by irradiation with light (ultraviolet light). Specifically, as shown in FIG. 10, an adhesive is applied to the gaps A formed on the inclined surfaces 21 a and 21 a of the pedestal 20 and the outer peripheral surface 13 of the holder 11. Further, a top cover (not shown) may be attached to the light source unit 2. In this case, the upper cover may be made of a material that transmits light (ultraviolet light), or a light (ultraviolet) transmitting window may be provided on the upper cover. Alternatively, a photocurable adhesive may be applied to a predetermined location before adjustment, and light may be irradiated and cured after adjustment. Other types of adhesives may be used. Further, the application position is not limited to the gap A.

(Other examples)
The laser beam scanning device, the adjusting device, and the adjusting method according to the present invention are not limited to the above-described embodiments, and can be variously changed within the scope of the gist.

  In particular, the type and arrangement of various optical elements constituting the optical path of the laser beam scanning apparatus are arbitrary. A laser diode having a plurality of light emitting points may be used as the light source.

It is a schematic perspective view which shows one Example of the laser beam scanning apparatus which concerns on this invention. It is explanatory drawing which shows the optical path of the cross section of a subscanning direction in the said laser beam scanning apparatus, and the beam shape in each optical element. It is a perspective view which shows an example of a condensing optical element. It is a perspective view which shows the light source unit mounted on the base. It is sectional drawing which shows a light source unit and an adjustment apparatus. A holder is shown, (A) is a perspective view, (B) is a side view, (C) is a front view. It is a perspective view which shows a base. It is a perspective view which shows a light source unit and an adjustment apparatus. It is an enlarged view which shows the engagement state of the protrusion for a clamp, and a clamp head. It is sectional drawing which shows the application position of the adhesive agent for fixation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Laser beam scanning apparatus 2 ... Light source unit 3 ... Laser diode 9 ... Condensing optical element (DOE)
DESCRIPTION OF SYMBOLS 11 ... Holder 13 ... Outer peripheral surface 14 ... Clamping protrusion 15 ... Positioning slope 20 ... Base 21 ... V groove shape part 22 ... Relief hole 30 ... Adjustment apparatus 31 ... Clamp head 32 ... Chuck mechanism 33 ... X-axis direction adjustment mechanism 34 ... Rotation adjustment mechanism

Claims (5)

A light source unit in which a light emitting element and a condensing optical element for condensing a beam emitted from the light emitting element are fixed to a holder;
A pedestal for positioning the holder by positioning an X-axis position along the optical axis, a Y-axis position along the main scanning direction, a Z-axis position along the sub-scanning direction, and a rotational position around the optical axis; ,
A laser beam scanning device comprising:
The holder has an outer peripheral surface having an arc shape centered on the optical axis, and a clamp protrusion protruding downward from the outer peripheral surface,
The pedestal has a V-groove shaped portion extending in the optical axis direction for placing the arc-shaped outer peripheral surface of the holder, and has a relief hole through which the projection for clamping is inserted,
A pair of positioning slopes having an angle with respect to the Y-axis-Z-axis plane are formed symmetrically in the X-axis direction on the lower part of the clamp projection protruding from the back surface of the pedestal,
A laser beam scanning device.   2. The laser beam scanning apparatus according to claim 1, wherein the condensing optical element has a collimator function and a cylindrical lens function integrated. An adjustment device for a laser beam scanning device according to claim 1 or 2,
A pair of clamp heads that contact the pair of positioning slopes formed on the clamp protrusion from the X-axis direction;
An X-axis direction adjusting mechanism for positioning the X-axis position by moving the clamp head in the X-axis direction;
A rotation adjusting mechanism for positioning the rotational position by rotating the clamp head around the optical axis;
An adjustment device comprising:   The adjusting device according to claim 3, wherein the clamp head has an arcuate portion that contacts the positioning slope from the X-axis direction. An adjustment method for a laser beam scanning device according to claim 1 or 2,
Placing the outer peripheral surface of the holder in an arc shape on the V-groove portion of the pedestal, and projecting the clamping protrusion from the relief hole to the back surface of the pedestal;
A step of bringing a pair of clamp heads into contact with a pair of positioning slopes formed on the clamp protrusion from the X-axis direction, and positioning the holder in the Y-axis direction and the Z-axis direction;
Adjusting the position of the clamp head in the X-axis direction;
Rotating the clamp head around the optical axis to adjust the rotational position;
An adjustment method characterized by comprising:

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