JP2000227566A - Scanning optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive and high-performance scanning optical device constituted so that image quality and reliability can be enhanced and a manufacturing cost is suppressed by preventing an image defect from occurring by enhancing the fitting accuracy of a cylinder lens, securing the strength of adhesion by making the thickness of an adhesive agent layer proper and suppressing the man-hour of a sticking process at the same time. SOLUTION: The cylinder lens 15 is provided with a projection part becoming a reference surface at both sides of the lower surface. By making the reference surface R1 abut on the bearing surface T1 of a frame body 11, the position and the attitude of the lens 15 are decided. Besides, the reference surface R1 of the lens 15 and the bearing surface T1 of the frame body 11 directly abut on each other. By making the side surface R2 of the lens 15 abut on the surface R2 of the frame body 11, deviation in a horizontal direction is suppressed. Then, adhesive agent B is included only between the sticking surface R3 of the lens 15 and the sticking surface T3 of the frame body 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning optical device used for an image forming apparatus in a laser beam printer, a digital copying machine or the like.

[0002]

2. Description of the Related Art A scanning optical device used for an image forming apparatus in a laser beam printer, a digital copying machine, or the like generally includes a light source unit 1 in which a semiconductor laser and a collimator lens are unitized as shown in FIG. A polygon mirror 2 for deflecting and scanning the laser beam emitted from the light source unit 1, a deflection scanning unit 3 in which a motor for rotating and driving the polygon mirror 2 is unitized, and a laser beam emitted from the light source unit 1 in the sub-scanning direction ( (Perpendicular to the deflection scanning plane), a cylinder lens 4 for forming an image on the polygon mirror 2, a scanning lens 5 for forming an image of the laser beam subjected to the deflection scanning on a photosensitive drum (not shown), a return mirror 6, and a laser beam are detected. Unit which unitizes BD sensor and BD lens etc. , BD unit 7 with a laser beam
, The deflection scanning unit 3, the cylinder lens 4, the scanning lens 5, the folding mirror 6, the BD mirror 8, and the BD unit 7 are assembled to a frame 9, and screws or other parts are provided. It is fixed by fixing means.

Since the cylinder lens 4 is small in size and weight, a method in which the cylinder lens 4 is bonded to a mounting seat surface provided on a frame 9 is often used. Although the cylinder lens portion in FIG. 6 is shown in FIG. 7 as an AA cross section, the position and posture of the cylinder lens 4 are determined by bringing the reference surface R1 into contact with the seating surface T1 of the frame 9. At the same time, the lateral displacement is suppressed by bringing the side surface R2 into contact with the wall surface R2 of the frame. Adhesive B between the lower surface of the cylinder lens 4 and the frame 9
Is applied, and the cylinder lens 4 is fixed to the frame 9 by curing the adhesive B. Adhesive B
Since the curing time can be shortened, an ultraviolet curable adhesive is frequently used.

FIGS. 7 (a) and 7 (b) show a case where the cylinder lens 4 is injection-molded with a plastic material and has projections serving as reference surfaces on both lower surfaces, and FIG. This shows a case where the lens 4 is polished from a glass material and the reference surface R1 on the lower surface is a flat surface.

[0005] The upper opening of the frame 9 is closed by a lid (not shown) after all necessary parts are incorporated into the frame 9. A laser beam emitted from a light source unit 1 passes through a cylinder lens 4 and rotates a polygon mirror 2.
Then, the light is reflected through the scanning lens 5 and the folding mirror 6 and emitted from an emission port 10 provided at a lower portion of the frame 9 toward a photosensitive drum (not shown). On the other hand, before being irradiated on the photosensitive drum, the laser beam is reflected by the BD mirror 8 upstream of the main scanning direction and guided to the BD unit 7,
The timing of the start of recording is determined by the electric signal taken out therefrom.

[0006]

However, in the above conventional example, as shown in FIGS. 7 (a), (b) and (c),
In the bonding and fixing of the cylinder lens 4, the bonding surface (T3,
The adhesive B applied to R3) enters between the frame body seating surface T1 and the cylinder lens reference surface R1. In (a),
The adhesive B applied to the bonding surface T3 flows out to the lower seating surface T1 by its own weight. In (b), a large amount of the adhesive B applied so as to fill a large gap in the bonded portion flows out to the surrounding seating surface T1. In (c), the bonding surface T3 has a concave shape with respect to the seating surface T1. However, since the step is small, the bonding surface T3 flows out to the surrounding seating surface T1 due to the surface tension of the adhesive B and capillary action. Become. As a result, the mounting accuracy decreases. The thickness of the layer of the adhesive B that has entered between the seating surface T1 and the reference surface R1 causes vertical displacement and inclination due to the thickness of the layer of the adhesive B, and abnormalities such as scanning line bending and spot collapse occur in the beam irradiated on the photosensitive drum. As a result, image quality such as straight curve and uneven density is reduced.

If the adhesive B sandwiched between the bonding surface T3 of the frame 9 and the bonding surface R3 of the cylinder lens is not appropriate and is too thin or too thick, the adhesive force is reduced and vibration is caused. There is a possibility that the cylinder lens 4 may fall off, and the reliability is reduced. For example, if it is too thin, it will peel off due to temperature changes, and if it is too thick, it will be insufficiently cured and the bonding strength will be insufficient. Further, as shown in FIG. 7 (b), air bubbles will enter the adhesive layer. It is also conceivable that the bonding area is insufficient and the bonding strength is reduced. In particular, when the adhesive layer is too thick, the curing time is prolonged, which increases the number of manufacturing steps and increases the cost of the apparatus.

SUMMARY OF THE INVENTION An object of the present invention is to improve the mounting accuracy of a cylinder lens to prevent the occurrence of an image defect, and to further improve the thickness of an adhesive layer in order to address the above-mentioned unresolved problems of the prior art. It is an object of the present invention to provide an inexpensive and high-performance scanning optical device which can secure the bonding strength by using the same method and at the same time reduce the number of steps in the bonding process, thereby improving the image quality, improving the reliability and suppressing the production cost.

[0009]

According to the present invention, there is provided a scanning optical apparatus comprising: a light emitting unit as a light source for emitting a light beam; a deflection scanning unit for deflecting and scanning the light beam; An optical component disposed in an optical path of the beam; and a frame for accommodating the optical component.
In a scanning optical device in which one cylinder lens is adhered and fixed to the frame, an abutment portion to be brought into direct contact with an opponent and an adhesive are attached to one or both adhesion contact sides of the frame and the cylinder lens. And a step formed of a portion, the adhesive portion is formed in a concave shape with respect to the abutting portion on the frame body side, or the adhesive portion is formed in a convex shape with respect to the abutting portion on the cylinder lens side. It is characterized by the following.

A scanning optical device according to the present invention comprises: a light emitting means as a light source for emitting a light beam; a deflection scanning means for deflecting and scanning the light beam; an optical component disposed on an optical path of the light beam; A frame for accommodating, and a scanning optical device for adhering and fixing one cylinder lens of the optical component to the frame, wherein one or both of the frame and the cylinder lens are directly contacted with the adhesion contact side. A step comprising an abutting portion to be brought into contact with an adhesive and a portion to which an adhesive is applied is provided, and a groove is provided between the abutting portion and the adhesive portion.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the illustrated embodiment. FIG. 1 is a schematic plan view of the entire scanning optical device of the embodiment. A light source unit 12 for outputting a laser beam, a deflection scanning unit 13, a polygon mirror 14 attached to the deflection scanning unit, a cylinder lens 15, a scanning lens 16, and a return mirror 17 are arranged on a frame 11. B represents an adhesive. A part of the laser beam deflected by the polygon mirror 14 is B
The light is reflected by the D mirror 18 and enters the BD unit 19.

The light source unit 12 generates a laser beam corresponding to information to be recorded. The laser beam is condensed in the sub-scanning direction by a cylinder lens 15 and reflected by the polygon mirror 14 of the deflection scanning unit 13. The deflection scanning unit 13 is rotated by a motor serving as a driving unit, and the reflection surface of the integrated polygon mirror 14 rotates around an axis, so that the reflected light of the laser beam moves in the main scanning direction. The scanning lens 16 functions to form an image of the laser beam as the scanning light reflected by the polygon mirror 14 on the surface of the photosensitive drum (not shown) and to keep the scanning speed in the main scanning direction on the surface of the photosensitive drum constant. I do.
The return mirror 17 reflects the laser beam as the scanning light toward the photosensitive drum. The BD mirror 18 reflects the laser beam on the upstream side in the main scanning direction relative to the irradiation of the photosensitive drum, and guides the laser beam to the BD unit 19. A BD sensor incorporated in the BD unit 19 detects a laser beam and outputs an electric signal for setting a writing start timing to a controller of the image forming apparatus.

FIG. 2 is a sectional view taken along line BB of FIG. 1 and shows a cylinder lens portion. The cylinder lens 15 is formed by injection-molding a plastic material, and has a shape having projections serving as reference surfaces on both lower surfaces. The position and orientation of the cylinder lens 15 are determined by bringing the reference surface R1 into contact with the seating surface T1 of the frame body 11. Here, the adhesive B is not interposed, and the reference surface R1 of the cylinder lens 15 and the seating surface T1 of the frame 11 are directly abutted. At the same time, the side surface R2 of the cylinder lens 15 is brought into contact with the surface R2 of the frame body 11, thereby suppressing the displacement in the horizontal direction. The adhesive B is applied only between the bonding surface R3 of the cylinder lens 15 and the bonding surface T3 of the frame 11.

The frame 11 has a step between the seating surface T1 and the bonding surface T3 such that the bonding surface T3 is lower and concave. The step size is determined so that the adhesive B does not protrude from the seat when the cylinder lens 15 is assembled. On the other hand, the cylinder lens 15 forms a step between the reference surface R1 and the bonding surface R3. The step size of the cylinder lens 15 is the bonding surface interval (R3-T3)
Is set so as to keep a gap dimension that makes In FIG. 2, the bonding surface R3 of the cylinder lens 15 is at a lower position than the seating surface T1 of the frame 11, but this is not a limitation for the purpose of making the bonding surface interval (R3-T3) appropriate.

The bonding surface interval (R3-T3) is the thickness of the adhesive layer, and is set so as to achieve both the securing of the adhesive strength and the suppression of the curing time of the adhesive B.

When an ultraviolet curable adhesive is used, the thickness of the adhesive layer is thin, usually about 10 to 50 μm. When the adhesive B is cured by an ultraviolet irradiator, the cylinder lens 15 is fixed to the frame 11.

Here, although the amount of the adhesive B and the adhesive area seem to be smaller than those of the conventional example, the cylinder lens 15
Is smaller in weight, so that the adhesive strength is sufficient even if the adhesive B is reduced as compared with the conventional example.

FIG. 3 shows a first modification in which the shape of the cylinder lens is different. The cylinder lens 15 is a combination lens, in which a polished glass lens 15a is incorporated inside an injection-molded plastic lens 15b, and the same configuration as in FIG. 2 is possible.

FIG. 4 shows a second modification, in which a groove G is formed between the seating surface T1 on the frame 11 side and the bonding surface T3.
The groove G can effectively prevent the adhesive B applied to the bonding surface T3 (R3) from protruding to the seating surface T1 (reference surface R1) as the abutting portion.

(A) is a plastic lens in which a convex portion is formed as a reference surface on both sides of the lower surface. In contrast to the shape described with reference to FIGS. It can be arranged at a position higher than the seating surface T1. The adhesive B applied to the bonding surface T3 is pushed and spread between the bonding surface R3 of the cylinder lens 15 and the protruding adhesive B enters the groove G and reaches the seating surface T1 and the reference surface R1. Absent. (b) shows a case where the lower surface of the glass lens is flat, but the adhesive B spread from the bonding surface remains in the groove G and does not reach the seating surface T1 reference surface R1 again.

FIG. 5 shows a third modification, in which the concave shape on the side of the frame 11 shown in FIG. 2 and the groove G between the seating surface T3 and the bonding surface R3 shown in FIG. It is a case where it is provided. In this example, a convex portion as an adhesive surface formed on the lower surface of the cylinder lens 15 can be reduced,
It is expected that deterioration of the optical performance of the cylinder lens 15 due to molding distortion can be reduced. Further, the shape of the groove G on the side of the frame 11 can be reduced, and the adhesive B protruding from the bonding surface enters the groove G and does not enter between the seating surface T1 and the reference surface R1. Also in this case, the step size between the reference surface R1 and the bonding surface R3 is set so as to maintain a gap size that makes the bonding surface interval (R3-T3) appropriate.

As described above, various combinations of steps on the surface of the frame 11 and the cylinder lens 15 on the side of the adhesive contact are possible. In any case, the reference surface for determining the position and posture of the cylinder lens 15 is made of an adhesive B
Is not interposed, and the cylinder lens 15 can be prevented from floating, and at the same time, the appropriate thickness of the adhesive layer can be maintained on the bonding surface.

As described above, in this embodiment, a step is provided which includes the abutting reference surface portion for directly abutting against the other party to determine the position and posture, and the bonding surface portion to which the adhesive B is applied. The step size is set so that the adhesive B applied to the surface abuts and does not protrude from the reference surface.
In the case where a step is provided on the fifth side, a convex shape in which the adhesive surface protrudes from the abutting reference surface is formed. The height of the convex shape at this time is set to such a size as to reach the adhesive applied to the adhesive surface at the bottom of the frame-side concave shape. When the reference surface of the cylinder lens 15 and the reference surface of the cylinder lens 15 are in direct contact with each other, it is possible to form a gap dimension such that the thickness of the adhesive B is appropriate on the bonding surface, secure the bonding strength, and extend the curing time. It is effective not to let it.

Further, a structure is also conceivable in which a groove G is formed between the abutting reference surface and the bonding surface to prevent the adhesive B from spreading to the reference surface.
It is preferable to form the groove G on one side.

In such a configuration, the adhesive B does not intervene in the abutting reference surface portion that determines the position and the posture, and the frame 11 and the cylinder lens 15 are directly in contact with each other. As a result, the cylinder lens 15 can be prevented from floating and can be prevented from shifting or tilting in height.

On the other hand, a gap is provided in the adhesive surface portion to which the adhesive B is applied, so that the thickness of the adhesive layer is appropriate in a state where the abutment reference surface portion is in contact.
It is possible to obtain the thickness of the adhesive layer that can secure the necessary adhesive strength. At the same time, since the adhesive layer does not become too thick, the curing time of the adhesive B can be suppressed.

[0027]

As described above, the scanning optical device according to the present invention can improve the mounting accuracy of the cylinder lens with respect to the frame by preventing the adhesive from entering the mounting reference plane, and can improve the accuracy of mounting the drum. Since the abnormality of the scanning beam applied to the surface can be prevented, there is an effect of improving image quality.

On the other hand, the thickness of the adhesive layer that can secure the required adhesive strength can be made large, and peeling and falling off of the cylinder lens due to vibration can be prevented, and thus there is an effect of improving the reliability of the apparatus.

At the same time, by making the adhesive layer thinner to secure the adhesive strength, the curing time of the adhesive is suppressed, so that the number of manufacturing steps can be reduced, and the manufacturing of the apparatus can be performed together with the reduction in the amount of the adhesive. This has the effect of reducing costs.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of an entire scanning optical device according to an embodiment.

FIG. 2B illustrates the structure of a cylinder lens portion in FIG.
It is -B sectional drawing.

FIG. 3 is a sectional view of a first modified example of a cylinder lens portion.

FIG. 4 is a sectional view of a second modification of the cylinder lens portion.

FIG. 5 is a sectional view of a third modification of the cylinder lens portion.

FIG. 6 is a plan view of an entire conventional scanning optical device.

FIG. 7 is a sectional view taken along line AA of FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Frame 12 Light source unit 13 Deflection scanning unit 14 Polygon mirror 15 Cylinder lens 16 Scanning lens 17 Folding mirror B Adhesive G Groove T1 Seat surface T2 Wall surface T3 Adhesive surface R1 Reference surface R3 Adhesive surface

Claims (3)

[Claims] 1. A light emitting means as a light source for emitting a light beam, a deflection scanning means for deflecting and scanning the light beam, an optical component arranged in an optical path of the light beam, and a frame for accommodating these components. In a scanning optical device in which one cylinder lens of the optical component is bonded and fixed to the frame, a contact portion for directly abutting on one or both of the frame and the cylinder lens in contact with the other. And a step for attaching an adhesive, and a concave portion is formed on the frame body side with respect to the abutting portion, or an adhesive portion is formed on the cylinder lens side with respect to the abutting portion. A scanning optical device characterized in that a convex shape is formed. 2. A light emitting device as a light source that emits a light beam, a deflection scanning device that deflects and scans the light beam, an optical component disposed on an optical path of the light beam, and a frame body that accommodates these components. In a scanning optical device for adhering and fixing one cylinder lens of the optical component to the frame, one or both of the frame and the cylinder lens are directly adhered to an abutment portion to be brought into contact with a mating part. A scanning optical device comprising: a step having a portion to which an agent is attached; and a groove provided between the abutting portion and the bonding portion. 3. The scanning optical device according to claim 1, wherein when the abutting portion is brought into contact, a gap is formed in the adhesive portion such that the thickness of the adhesive layer becomes appropriate.