JPH0811348A - Beam scanning apparatus - Google Patents

Abstract

PURPOSE:To provide a beam scanning apparatus equipped with an adjusting mechanism capable of performing the adjustment of a beam scanning line in a main scanning direction and a sub-scanning direction without imparting strain to the seat surface of an optical unit. CONSTITUTION:An optical unit 1 is placed on a plate 2 having an angle of inclination with respect to the scanning surface of beam. The plate 2 is placed on a main body not showing in a drawing and made revolvable around a pin 7. The optical unit 1 is made revolvable around a pin 8 and made movable in an irradiation direction. Since the optical unit can be rotated and moved while the seat surface thereof is brought into contact with the plate, the adjustment of a beam scanning line in main scanning and sub-scanning directions can be performed without imparting strain to the seat surface of the optical unit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a beam light scanning device, and more particularly, it adjusts a deviation of a beam scanning a photoconductor in the main scanning direction and a deviation in a sub scanning direction orthogonal to the main scanning direction. The present invention relates to a beam light scanning device having an adjusting mechanism.

[0002]

2. Description of the Related Art A conventional beam light scanning device has a light source for emitting a modulated beam, a rotary polygon mirror for deflecting and scanning the beam emitted from the light source, and an f.theta. Imaging optical system. . It is known that in an apparatus having such a configuration, a deviation in the main scanning direction and a deviation in parallelism between scanning lines occur due to the accuracy of the fθ imaging optical system and the mounting accuracy of the optical unit and the photoconductor.

As prior arts proposing to correct this deviation, for example, there are those described in JP-A-2-269304 and JP-A-2-19869.
And it demonstrates with reference to FIG. In FIG. 11, 5
Reference numeral 0 is an optical unit, 51 is a plate, and the optical unit 50 is provided with four mounting legs 52. As shown in detail in FIG. 12, each mounting foot 52 is provided with a female threaded hole 52a, and the female thread of the hole 52a is male threaded. The height adjusting screw 54 is fitted. A screw 53 provided in the plate 51 is screwed into a central hole of the height adjusting screw 54, and a free screw 53 is inserted into the height adjusting screw 54.

Now, assuming that the beam scanning line 56 on the photoconductor 55 in FIG. 11 has a deviation in a direction orthogonal to the main scanning direction like 56a, the heights of the two legs on the right side of the optical unit 50 are set to be the same. By rotating and lowering the height adjusting screw 54, the beam scanning line 56 in a desired direction can be corrected.

As another prior art related to the present invention, there is Japanese Patent Laid-Open No. 4-119754 in which an optical unit can be swung by using a screw and a pin.

[0006]

However, in the above-mentioned prior art, the foot 52 of the optical unit 50 is moved up and down by turning the height adjusting screw 54, and the seat surface 50a of the optical unit is distorted. Occurs, which adversely affects the optical components fixed in the optical unit 50.

The object of the present invention is to eliminate the above-mentioned problems of the prior art, and to adjust the beam scanning line in the main scanning direction and the sub scanning direction without giving distortion to the seating surface of the optical unit. An object of the present invention is to provide a beam light scanning device having an adjusting mechanism.

[0008]

In order to achieve the above object, the invention according to claim 1 is an optical unit having a light source section for emitting a beam, a rotary polygon mirror, an fθ lens and the like, and the optical unit. And a main body on which the plate is placed. The optical unit rotates and irradiates with its seat surface in contact with the upper surface of the plate. Is configured to be movable in a direction, and the plate is configured to be rotatable with its seat surface in contact with the bottom surface of the main body. By rotating and moving the optical unit, the main scanning direction of the beam scanning line can be adjusted. It is characterized in that the adjustment is performed in the sub-scanning direction by rotating the plate.

According to a second aspect of the present invention, a flat plate on which the optical unit is mounted and a folding mirror for folding the beam emitted from the optical unit toward the photoconductor is attached, and the plate. A main body to be placed, and the optical unit is configured to be movable in the rotation and irradiation directions with the seat surface of the plate in contact with the upper surface of the plate, and the plate has its seat surface on the bottom surface of the main body. It is configured so as to be rotatable in a state of being in contact with the optical unit, and the rotation and movement of the optical unit adjusts the main scanning direction of the beam scanning line, and the rotation of the plate adjusts the sub scanning direction. Is characterized by.

[0010]

According to the invention of claim 1, since the plate on which the optical unit is mounted is inclined with respect to the scanning surface of the beam, the seat surface of the plate is brought into contact with the bottom surface of the main body. When rotated in this state, the adjustment of the beam scanning line in the sub-scanning direction, that is, the deviation of the parallelism between the scanning lines is corrected. Further, by rotating and moving the optical unit with its seat surface in contact with the plate, adjustment of the beam scanning line in the main scanning direction, that is, correction of balance deviation and magnification deviation in the main scanning direction. You can

According to the invention of claim 2, the plate is flat, but since the plate has a folding mirror for folding the beam emitted from the optical unit toward the photosensitive member, the same as in claim 1, When the plate is rotated with its seat surface in contact with the bottom surface of the main body, the beam scanning line can be adjusted in the sub-scanning direction. Also, by rotating and moving the optical unit with its seat surface in contact with the plate, the main scanning direction of the beam scanning line can be adjusted.

According to the inventions of claims 1 and 2,
Since the rotation and movement operations are performed while the seat surface of the optical unit is in contact with the plate, the above adjustment can be performed without giving distortion to the seat surface of the optical unit.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. FIG. 1 shows a perspective view of a main part of an embodiment of the present invention, and FIG. 2 shows a side view of FIG. 1 viewed from the direction of arrow A.

In the figure, reference numeral 1 denotes an optical unit, which can be rotated around a rotation center pin 8.
Moreover, it has a mechanism capable of moving in a direction perpendicular to the axis of the photoconductor. Details of this mechanism will be described later with reference to FIG. Further, the optical unit 1 has a hole 9a having a rotationally movable clearance so that a bearing surface (datum surface) which is a rotationally movable surface is attached to the plate 2 with a screw 9.
Inside the optical unit 1, as shown,
A light source 101 for emitting a modulated beam, a collimator lens 102 for collimating the beam, and a rotary polygon mirror 103.
And the fθ lens 104 are arranged in a predetermined positional relationship. Reference numeral 105 denotes a photoconductor (or an image carrier). The rotation center pin 8 is located at the intersection of the beam at the start point 106b and the end point 106c of the image area 106a on the photoconductor 105, which extends in the direction opposite to the irradiation direction.

The plate 2 has the optical unit 1 mounted thereon and is rotatable around a rotation center pin 7. The plate 2 has an inclination of an angle θ in the irradiation direction of the beam of the photoconductor 105, a screw hole for mounting the optical unit 1, and the plate 2 is screwed to the main body 3 side.
Hole with clearance for mounting by 0
a. Seats 4a, 5a, 6a for mounting the adjusting screws 4, 5, 6 are fixed on the plate 2.

The plate 2 is mounted on the main body 3, as is apparent from FIG. The main body 3 has a flat bottom surface, and has a wall surface 3a on the right side in the illustrated example. The screw 4 which is screwed into the screw hole of the seat 4a is attached to the wall surface 3a.
The tip of is in contact. A contraction spring 4b is preferably provided between the seat 4a and the wall surface 3a.

Next, with reference to FIG. 3, the configuration of the rotation center pin 8 of the optical unit 1 and its periphery will be described in detail. As shown, the rotation center pin 8 is composed of an upper plate portion 8b having two elongated holes 8a and a pin 8c extending vertically from the center of the upper plate portion 8b. The portion 8b is movably fixed to the screw holes 8d and 8e provided on the bottom surface of the optical unit 1 by the screws 11 passing through the elongated holes 8a and 8b. The pin 8c is passed through the elongated hole 8f. Therefore, as shown in FIG. 2, when the screw 6 held by the seat 6a fixed to the plate 2 is advanced toward the optical unit 1, the optical unit 1 is moved to the elongated holes 8a, 8b and the elongated holes. It can be moved in the longitudinal direction of 8f.

Next, referring to FIG. 4, the adjusting screw 5 of FIG.
Will be described in detail. The seat 5a is fixed to the plate 2 with a screw, and the screw 5 is screwed into a screw hole provided in the seat 5a. A contraction spring 5b is provided between the optical unit 1 and the seat 5a, and the tip of the screw 5 is in contact with the wall surface of the optical unit 1. Therefore, when the screw 5 is turned to advance its tip toward the optical unit 1, the optical unit 1 rotates counterclockwise around the rotation center pin 8. On the contrary, turn the screw 5 to attach the tip to the optical unit 1.
When the optical unit 1 is advanced in the opposite direction, the optical unit 1 rotates clockwise about the rotation center pin 8 due to the action of the contraction spring 5b.

Next, a description will be given of a method of correcting the scanning line in the main scanning direction and the direction orthogonal to the scanning line in the light beam scanning device having the above-mentioned structure.

As shown in FIG. 5 (a), when the optical unit 1 is placed on the plate 2 to assemble the beam light scanning device, the beam scanning unit is generally mounted in the main scanning direction due to processing accuracy and mounting error of the optical components. A magnification shift and a parallelism shift between scan lines occur. For example, as shown in FIG. 2 (b), even though the desired scan line is 20,
The scanning line 21 has the above-described magnification deviation in the main scanning direction and parallelism deviation between the scanning lines. Here, 20a is the midpoint of the scanning line 20, and 21a is the midpoint of the scanning line 21.

Here, in this embodiment, the screw 10 of FIG. 1 is loosened so that the plate 2 can be swung from the main body 3, and the screw 4
Send in. Then, as shown in FIG. 6 (a), the plate 2 rotates clockwise about the pin 7. As a result, the optical unit 1 mounted on the plate 2 also rotates in the same direction. By this rotation, the scanning line 21 becomes parallel to the desired scanning line 20 as shown in FIG. Here, the screw 10 is tightened to fasten the plate 2 and the main body 3.

In the above adjustment, the deviation of the magnification balance in the main scanning direction, that is, the scanning line length a'on both sides of the midpoint 21a is detected.
And b'are not equal, the problem remains. Therefore, in this embodiment, the screw 9 shown in FIG. 1 is loosened, and the adjusting screw 5 is pulled in under this state. By pulling in the adjusting screw 5, the optical unit 1 is moved to the pin 8 as shown in FIG. 7 (a).
Rotate in the clockwise direction with respect to, and the misalignment of the scanning lines is corrected. That is, as shown in FIG. 2B, the lengths a ′ and b ′ on both the left and right sides of the midpoint 21a of the scanning line 21.
Are equal.

However, in this adjustment, a magnification shift in the scanning direction still occurs. That is, as is apparent from FIG. 7B, there remains a problem that the length (a '+ b') of the scanning line 21 is not equal to the desired main scanning line length (a + b). Therefore, in this embodiment,
With the screw 11 in FIG. 3 loosened, the adjusting screw 6 is retracted to move the optical unit 1 in the direction of the arrow z as shown in FIG. 8 (a). Then, the optical unit 1 is moved in the irradiation axis direction away from the photoconductor along the elongated hole 8f, and as shown in FIG.
= (A '+ b'), and a = b = a '= b'. Here, the screws 9 and 11 are tightened to fasten the optical unit 1 to the plate 2 and the pin 8 to the optical unit 1.

By the above adjustment, the magnification shift of the scanning line 21 in the scanning direction is corrected, but as shown in FIG. 8B, the synchronization between the scanning lines is synchronized with the desired scanning line 20. Deviation x and parallel deviation y orthogonal to the main scanning direction
And will remain. However, these deviations are
By the correction for electrically controlling the writing timing of the optical unit 1, the correction can be perfectly performed as shown in FIG.

As described above, according to the present embodiment, simply by moving the seat surface of the optical unit 1 on the plate 2, the deviation of the parallelism between the scanning lines and the balance of the beam scanning lines in the main scanning direction can be achieved. Deviation and magnification deviation can be corrected, so that the seating surface of the optical unit is not distorted, and thus, the optical components fixed in the optical unit 1 are not adversely affected. Can be played.

Next, a second embodiment of the present invention will be described with reference to FIG. This embodiment shows a flat plate 30.
Different from the first embodiment in that the folding mirror 31 fixed to the plate 30 is provided immediately after the fθ imaging optical system, the configuration of other parts is the same or equivalent. In this embodiment, by rotating the plate 30 around the pin 7 by the same means as in the first embodiment, it is possible to correct the deviation of the parallelism between the scanning lines. Also, the optical unit 1
When the lens is rotated about the pin 8, the optical path length of the beam emitted from the light source to the photosensitive member can be changed by the action of the folding mirror 31, so that the deviation of the scanning line balance can be corrected. Further, by moving the optical unit 1 in the irradiation axis direction so as to move away from or approach the photoconductor, it is possible to correct the magnification shift of the scanning line.

According to this embodiment, in addition to the effect of the first embodiment, since the plate may be flat, it has the advantage of being easy to manufacture.

[0028]

According to the first and second aspects of the present invention, the optical unit is rotated and moved while the seat surface of the optical unit is in contact with the plate to adjust the main scanning direction and the sub scanning direction of the beam scanning line. Therefore, there is an effect that the above adjustment can be performed without giving a strain to the seat surface of the optical unit. Further, as a result, there is an effect that the optical components fixed in the optical unit are not adversely affected.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of an embodiment of the present invention.

FIG. 2 is a side view in the direction A of FIG.

3 is a detailed perspective view of a part of FIG. 1. FIG.

FIG. 4 is a detailed side view of a portion of FIG.

FIG. 5 is an explanatory diagram showing a state before adjustment of the beam light scanning device.

FIG. 6 is an explanatory diagram showing a method of adjusting the deviation in the sub-scanning direction.

FIG. 7 is an explanatory diagram showing a method of adjusting the first deviation in the main scanning direction.

FIG. 8 is an explanatory diagram showing a method of adjusting the second deviation in the main scanning direction.

FIG. 9 is an explanatory diagram showing a state in which deviations in the main and sub-scanning directions have been completely corrected.

FIG. 10 is a perspective view showing a schematic configuration of a second embodiment of the present invention.

FIG. 11 is a perspective view showing a schematic configuration of a conventional beam light scanning device.

FIG. 12 is a diagram showing details of a part of the configuration of FIG. 11;

[Explanation of reference numerals] 1 ... Optical unit, 2 ... Plate, 3 ... Main body, 4, 5,
6 ... adjusting screw, 7, 8 ... pin, 9, 10 ... screw, 30 ...
Plate, 31 ... folding mirror, 101 ... light source, 102
... Collimator lens, 103 ... Rotating polygon mirror, 104 ... f
θ lens, 105 ... Photoconductor.

Claims (2)

[Claims] 1. A light source unit for emitting a beam, a rotary polygon mirror,
The optical unit has an fθ lens and the like, a plate on which the optical unit is mounted and which is inclined with respect to a beam scanning surface, and a main body on which the plate is mounted. Is configured to be movable in the rotation and irradiation directions while being in contact with the upper surface of the plate, and the plate is configured to be rotatable with its seat surface in contact with the bottom surface of the main body. A beam light scanning device characterized in that a main scanning direction of a beam scanning line is adjusted by rotating and moving, and a sub scanning direction is adjusted by rotating the plate. 2. A light source unit for emitting a beam, a rotary polygon mirror,
An optical unit including an fθ lens and the like, a flat plate on which the optical unit is mounted, and a folding mirror that returns the beam emitted from the optical unit toward the photoconductor is mounted, and the plate are mounted. The optical unit is configured to be movable in the rotation and irradiation directions with the seat surface of the plate in contact with the upper surface of the plate, and the plate has its seat surface in contact with the bottom surface of the main body. The optical unit is configured to be rotatable, and the main scanning direction of the beam scanning line is adjusted by rotating and moving the optical unit, and the sub-scanning direction is adjusted by rotating the plate. Beam light scanning device.