JP2009015091A - Scanning optical apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scanning optical apparatus in which a bow adjustment is performed with an excellent workability even in a narrow space without turning a reflection mirror by adjusting the bending quantity of the reflection mirror by turning an adjustment screw with a tool without pressing the screw. <P>SOLUTION: The scanning optical apparatus comprises a bow adjustment mechanism 14 arranged at the center in the width direction of a frame 15 which supports both ends of the longitudinal direction of the reflection mirror 13 via a spring member 16, and the bow adjustment mechanism 14 is composed of: a holding bracket 17 which is engaged with the central part in the width direction of the refection mirror 13; a compressed spring 18 which is compressed between the holding bracket 17 and the frame 15 and attracts the center of the width direction of the reflection mirror 13 in one direction via the holding bracket 17; and the adjustment screw 19 which is engaged with the frame 15 movably forward and backward and pressurizes the center of the width direction of the reflection mirror 13 in the direction opposite to the direction of attracting by the compressed spring, wherein a polygonal column part 19b is formed at a part of the outer diameter part of the adjustment screw 19. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a scanning optical apparatus having a bow adjustment mechanism for correcting a curvature (“bow”) of a scanning line on an image carrier by deforming a reflecting mirror.

  2. Description of the Related Art Image forming apparatuses such as copying machines and printers that form images by electrophotography are equipped with a scanning optical device such as a laser scanner unit (LSU).

  For example, in a laser scanner unit, a collimator lens, a cylindrical lens, an fθ lens as a scanning lens, various optical components such as a reflection mirror, a polygon mirror as a polarizing means, a polygon motor that rotationally drives this, etc. The laser beam emitted from the laser diode as the light source is incident on the polygon mirror through the collimator lens and the cylindrical lens, and the laser beam reflected by the polygon mirror is reflected through the scanning lens. And imaged on an image carrier such as a photosensitive drum and exposed and scanned to form an electrostatic latent image corresponding to the image information on the image carrier. The electrostatic latent image formed on the image carrier is developed by a developing device using toner as a developer to be visualized as a toner image, and this toner image is recorded on a recording material such as paper by a transfer device. Transcribed above.

  By the way, in such a scanning optical device, there is a problem that the scanning line on the image carrier is curved due to a manufacturing error or an assembly error of an optical component such as a lens or a reflection mirror, and the image quality is deteriorated.

Therefore, for example, in Patent Document 1, a reflection mirror, which is one of the optical members, is held by a holding member, a scanning line curve adjusting unit is provided at the center in the longitudinal direction of the reflection mirror, and a light beam incident on the reflection mirror is provided. Proposals have been made to adjust the amount of deflection.
JP 2006-017881 A

  However, the scanning line curve adjusting means proposed in Patent Document 1 rotates the adjustment screw while pressing it with a screwdriver to bend and deform the plate spring for pressure adjustment, and adjusts the pressing force of the plate spring to the reflection mirror. Thus, since the method of correcting the curvature of the scanning line on the image carrier is adopted, the pressing force of the driver becomes the rotational force to the reflection mirror around the holding member, and this rotational force holds the reflection mirror of the holding member. When the force is larger than the force, there arises a problem that the imaging position is shifted due to the reflection mirror rotating with respect to the set angle.

  Further, due to the configuration of the scanning optical device, there is a problem that bow adjustment cannot be easily performed when a tool such as a screwdriver cannot be inserted into the back side of the reflecting mirror.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to adjust the deflection amount of the reflecting mirror without rotating the reflecting mirror by turning the adjusting screw without pressing it with a tool even in a narrow place. Thus, an object of the present invention is to provide a scanning optical device capable of performing bow adjustment with good workability.

  In order to achieve the above object, according to the first aspect of the present invention, a bow adjustment mechanism is disposed at the center in the width direction of the frame that supports both ends of the reflection mirror in the longitudinal direction via spring members, and the bow adjustment mechanism is disposed on the reflection mirror. A holding bracket that engages with the center in the width direction of the mirror, a compression spring that is compressed between the holding bracket and the frame and that pulls the center in the width direction of the reflecting mirror in one direction via the holding bracket; and the frame In the scanning optical device constituted by an adjustment screw that is screwed so as to be able to advance and retract and presses the center in the width direction of the reflection mirror in the direction opposite to the direction of attraction by the compression spring, the outer diameter portion of the adjustment screw A polygonal columnar part is formed in part.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, a tool insertion hole is formed in a part of the holding bracket.

  A third aspect of the invention is characterized in that, in the first or second aspect of the invention, the holding bracket is extended to below the adjustment screw.

  According to the first aspect of the present invention, since the polygonal columnar portion is formed on a part of the outer diameter portion of the adjustment screw of the bow adjustment mechanism, a tool such as a wrench can be inserted even in a narrow space to adjust the polygonal column portion of the adjustment screw. The bow can be adjusted easily with good workability by adjusting the pressing force to the reflecting mirror by turning the adjusting screw with the tool, but it does not turn while pressing the adjusting screw with the screwdriver. There is a problem that almost no force is generated to rotate the mirror with respect to the frame, and the reflecting mirror rotates with respect to the set angle, so that the imaging position of the light beam on the image carrier is shifted. Absent.

  According to the second aspect of the present invention, it is possible to easily adjust the bow by inserting a tool such as a wrench from a tool insertion hole formed in a part of the holding bracket and turning the adjusting screw with good workability.

  According to the third aspect of the present invention, since the holding bracket is extended to below the adjustment screw, even if the tool is detached from the adjustment screw during the bow adjustment operation, the removed tool is dropped because it is received by the holding bracket. In addition, damage to the polygon motor, lens, and the like due to falling tools can be prevented.

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

  FIG. 1 is a partial perspective view showing the internal structure of a scanning optical apparatus according to the present invention, and FIG. 2 is a cross-sectional view taken along line AA of FIG.

  A scanning optical device 1 according to the present invention includes a polygon mirror 3 as a polarizing means and a polygon motor 4 that rotationally drives the polygon mirror 3 at the center of a housing 2 formed in a rectangular box shape with resin. Two scanning optical systems 20 and 30 are arranged symmetrically on both sides. As shown in FIG. 2, a cover 5 is attached to the upper part of the housing 2, but FIG. 1 shows a state in which the cover 5 is removed to show the internal structure of the housing 2. .

  Here, each of the scanning optical systems 20 and 30 includes a laser diode (not shown) that is a light source, a collimator lens 7, a cylindrical lens 8, two fθ lenses 9 and 10 that are scanning lenses, and three reflecting mirrors 11, 12, and 13. The laser light emitted from the laser diodes of the scanning optical systems 20 and 30 is condensed into a linear light beam by the collimator lens 7 and the cylindrical lens 8, and then rotated by the polygon motor 4. Incident from two symmetrical directions with respect to the polygon mirror 3.

  As described above, the laser light incident on the polygon mirror 3 is polarized and scanned by the polygon mirror 3, and the reflected light passes through the two fθ lenses 9 and 10 and the three reflection mirrors 11, 12, and 13 and is shown in FIG. The imaged light beam formed on the drum 50 is scanned on the photosensitive drum 50 in the main scanning direction by the rotation of the polygon mirror 3, and is scanned in the sub-scanning direction by the rotation of the photosensitive drum 50. An electrostatic latent image is formed on the surface. The scanning optical device 1 according to this embodiment exposes and scans two photosensitive drums 50 with two laser beams. A full-color laser printer or the like is provided with two such scanning optical devices 1, yellow, The four photosensitive drums 50 are exposed and scanned by laser beams corresponding to magenta, cyan, and black images.

  Thus, in this embodiment, the curvature of the scanning line on the image carrier is corrected by the bow adjustment mechanism 14 provided on the reflection mirror 13 as shown in FIG. 14 and the bow adjustment method will be described with reference to FIGS.

  3 is a front view of a reflecting mirror provided with a bow adjusting mechanism, FIG. 4 is an enlarged cross-sectional view of a portion B in FIG. 3, FIG. 5 is a cross-sectional view taken along the line CC in FIG. FIG. 7 is a perspective view of the holding bracket, FIG. 8 is a perspective view of the reflecting mirror showing the bow adjustment method, and FIG. 9 shows a state in which the adjusting screw is turned with a hexagon wrench. It is a fragmentary perspective view.

  The reflection mirror 13 is supported at both ends in the longitudinal direction by a sheet metal spring member 16 by a channel-shaped frame 15 whose upper surface is open, and a bow adjusting mechanism 14 is disposed at the center in the longitudinal direction.

  The bow adjusting mechanism 14 includes a holding bracket 17 that engages with the central portion in the width direction of the reflecting mirror 13, and is retracted between the holding bracket 17 and the frame 15 and the width of the reflecting mirror 13 through the holding bracket 17. The two compression springs 18 that pull the center in the downward direction in FIGS. 3 and 4 and the boss 15A projecting from the center in the longitudinal direction of the bottom surface of the frame 15 are screwed so as to be movable back and forth (movable up and down) and reflected. The mirror 13 is composed of an adjustment screw 19 that presses the center in the width direction in the direction opposite to the attracting direction by the compression spring 18 (upward in FIGS. 3 and 4).

  Here, as shown in FIG. 7, the holding bracket 17 is a channel-shaped member having an open upper surface, and a pair of engaging claws bent inward at the center in the width direction of the left and right upper edges. 17a is integrally formed, and leaf springs 17b bent in an inverted U shape toward the inside are integrally formed on both sides of each engaging claw 17a. A circular hole 17c is formed at the center in the width direction of the bottom surface of the holding bracket 17, and two crescent-shaped locking holes 17d for locking one end (lower end) of the compression spring 18 are provided on both sides thereof. Each is formed.

  Thus, the holding bracket 17 is fitted with the opening upward so as to cover the frame 15 and the central portion in the longitudinal direction of the reflection mirror 13 held by the frame 15 from below, and the engagement claw 17 a By being engaged with the upper surface, it is held by the reflection mirror 13. Then, the holding bracket 17 is biased downward by two compression springs 18 that are compressed between the holding bracket 17 and the frame 15, whereby the engaging claw 17 a of the holding bracket 17 is engaged with the reflection mirror 13. At the same time, the longitudinal center of the reflecting mirror 13 is pulled downward. As a result, the reflecting mirror 13 is bent and deformed so that the center in the longitudinal direction is convex downward. The reflection mirror 13 is held by the leaf springs 17b of the holding bracket 17 at the center in the width direction in two directions perpendicular to the longitudinal direction (perpendicular to the plane of FIG. 3 and FIG. 4).

  Further, as shown in detail in FIG. 5, a screw hole 15a is formed in the boss portion 15A projecting from the longitudinal center of the bottom surface of the frame 15, and the screw of the adjusting screw 19 is provided in the screw hole 15a. The part 19a is screwed from below. The tip of the adjusting screw 19 facing the frame 15 is in contact with the center in the longitudinal direction of the bottom surface of the reflecting mirror 13. Further, a hexagonal columnar portion 19b is integrally formed at a portion adjacent to the screw portion 19a of the outer diameter portion protruding downward from the frame 15 of the adjustment screw 19, and as shown in FIGS. A cross hole 19c for engaging the driver is formed on the lower end surface. As shown in FIG. 6, the cross hole 19c is exposed downward from a circular hole 17c formed on the bottom surface of the holding bracket 17. is doing.

  Incidentally, as shown in FIG. 3, a rectangular tool insertion hole 17e is formed in the side portion of the holding bracket 17, and the hexagonal columnar portion 19b of the adjusting screw 19 faces the tool insertion hole 17e. It is out.

  Thus, as described above, the reflecting mirror 13 is bent and deformed so that the central portion in the longitudinal direction thereof is attracted downward by the two compression springs 18 and protrudes downward, but the adjusting screw 19 is in contact with the lower surface thereof. It is bent and deformed so as to be convex upward by pressing upward. Therefore, if the adjustment screw 19 is turned to adjust the bow and the upward pressing force against the reflection mirror 13 by the tip of the adjustment screw 19 is adjusted, the scanning line on the photosensitive drum 50 shown in FIG. it can.

  By the way, in this embodiment, since the hexagonal columnar portion 19b is formed on a part of the adjustment screw 19, when turning the adjustment screw 19 in the bow adjustment, as shown in FIGS. The hexagon wrench 40 can be inserted from the tool insertion hole 17e formed in the portion, the tip of the hex wrench can be engaged with the hexagonal columnar portion 19b of the adjustment screw 19, and the adjustment screw 19 can be rotated by the hexagon wrench 40.

  Therefore, according to the present embodiment, it is possible to easily adjust the bow with good workability by inserting the hexagon wrench 40 and turning the adjusting screw 19 to adjust the pressing force to the reflecting mirror 13 even in a narrow place. Can do. In this case, since the adjusting screw 19 is not rotated while being pressed by a driver as in the prior art, almost no force is generated to rotate the reflecting mirror 13 with respect to the frame 15, and the reflecting mirror 13 is set at a set angle. , The image formation position of the laser beam on the photosensitive drum 50 is not shifted.

  Further, the adjustment allowance of the reflection mirror 13 in the bow adjustment is actually a minute amount within 0.2 mm, and the rotation of the adjustment screw 19 is less than half rotation, but a driver is required to turn the adjustment screw 19 by a minute angle. The hex wrench 40 is more suitable than the hex wrench 40, and a reduction mechanism or a mechanism for changing the adjustment direction is not required for the rotation of the adjustment screw 19 by the hex wrench 40. Therefore, the number of parts of the bow adjustment mechanism 14 is reduced and the cost is reduced. You can go down.

  Furthermore, in the present embodiment, the holding bracket 17 is formed in a channel shape, and the bottom of the holding bracket 17 is wrapped under the adjustment screw 19 so as to cover the adjustment screw 19 from below. Even if the hexagon wrench 40 is removed from the adjusting screw, the removed hexagon wrench 40 is received by the holding bracket 17 so that the hexagon wrench 40 does not fall. Damage such as is prevented. Although not shown, the same effect can be obtained by forming a retaining shape having an outer diameter larger than that of the hexagonal columnar portion 19b on the head of the adjusting screw 19 or providing a stopper as a separate member.

It is a perspective view which shows the internal structure of the scanning optical apparatus which concerns on this invention. It is the sectional view on the AA line of FIG. It is a front view of the reflective mirror provided with the bow adjustment mechanism. FIG. 4 is an enlarged cross-sectional view of a B part in FIG. 3. It is CC sectional view taken on the line of FIG. It is a bottom view (figure of the arrow D direction of FIG. 3) of a bow adjustment mechanism. It is a perspective view of a holding bracket. It is a perspective view of the reflective mirror which shows a bow adjustment method. It is a fragmentary perspective view which shows a mode that the adjustment screw of a bow adjustment mechanism is rotated with the hexagon wrench.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Scanning optical apparatus 2 Housing | casing 3 Polygon mirror 4 Polygon motor 5 Cover 7 Collimator lens 8 Cylindrical lens 9,10 f (theta) lens 11-13 Reflection mirror 14 Bow adjustment mechanism 15 Frame 15A Frame boss part 15a Boss part screw hole 16 Spring Member 17 Holding bracket 17a Holding bracket engaging claw 17b Holding bracket leaf spring 17c Holding bracket circular hole 17d Holding bracket locking hole 17e Holding bracket tool insertion hole 18 Compression spring 19 Adjustment screw 19a Adjustment screw thread 19b Hexagonal columnar part of adjustment screw 19c Cross hole of adjustment screw 20, 30 Scanning optical system 40 Hexagon wrench (tool)
50 Photosensitive drum

Claims (3)

A bow adjustment mechanism is disposed at the center in the width direction of the frame that supports both ends of the reflection mirror in the long direction via spring members, and the bow adjustment mechanism is engaged with the center portion in the width direction of the reflection mirror; and A compression spring that is mounted between the holding bracket and the frame and that pulls the center in the width direction of the reflecting mirror in one direction through the holding bracket; and a center in the width direction of the reflecting mirror that is threadably engaged with the frame In a scanning optical device constituted by an adjustment screw that presses in the direction opposite to the pulling direction by the compression spring,
A scanning optical device, wherein a polygonal columnar part is formed on a part of the outer diameter part of the adjusting screw.   The scanning optical device according to claim 1, wherein a tool insertion hole is formed in a part of the holding bracket. The scanning optical device according to claim 1, wherein the holding bracket is extended to below the adjustment screw.

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