JPH07134259A - Optical device for scanning with laser - Google Patents

Abstract

PURPOSE:To eliminate the need for optical axis adjustment at the time of assembly by mounting an LD unit integrated with a laser diode mounted on a flexible printed circuit board, a collimating lens and an aperture to a chassis positioned by means of guide pins front direction perpendicular thereto. CONSTITUTION:The laser diode unit (LD unit) 1 consists of the flexible printed circuit board (FPC) 5 formed by mounting the laser diode 6 and a synchronizing sensor 7 on the flexible printed circuit board, the laser diode holder (LD holder) 2, a collimating lens frame 3 and the aperture 4. The laser diode 6 is inserted and adhered to the recessed part at one end face of the LD holder 2. The collimating lens frame 3 and the aperture 4 are inserted from the other end face of the LD holder 2 and are adhered by using a notch formed in the top surface part of the LD holder 2. The LD unit 1 is positioned by means of the guide pins 9 disposed on the plane of the chassis 11 and is fixed by means of screws 8 in screwing holes 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser scanning optical device, and more particularly to a laser scanning optical device used in an electrophotographic printer.

[0002]

2. Description of the Related Art Conventionally, this type of laser scanning optical device is
The chassis is equipped with a laser diode, a collimating lens for laser light, a correcting lens, a polygon mirror, an fθ first lens, an fθ second lens, and a synchronization sensor, and the light generated from the laser diode is passed through the collimating lens and the correcting lens. The deflected light reflected by the rotating polygon mirror and deflected at a constant angular velocity is deflected at a constant velocity by the fθ first lens and the fθ second lens to form an image on the exposure surface, but passes through the fθ first lens. A part of the generated light is received by the synchronous sensor.

5 and 6 are a sectional view and a perspective view of the structure of a laser diode and a collimating lens portion of a conventional scanning optical device. 5 and 6, the printed circuit board 24 having the laser diode 6 mounted thereon is soldered to the A housing 22 having the collimating lens frame 3 having the collimating lens mounted thereon while adjusting the optical axes in the horizontal and vertical directions. Alternatively, the A housing 22 may be attached to the B housing 23 attached to the chassis 21 with the screw 26 while adjusting the optical axis in the horizontal and vertical directions again by adhering with an adhesive. ing.

[0004]

In assembling the laser diode and the collimating lens portion in the above-described conventional laser scanning optical device, the optical axis adjustment in the horizontal and vertical directions is performed twice. Further, the screw tightening direction is also inefficient from the side of the chassis, and since the printed circuit board is used, it is difficult to downsize the entire device.

[0005]

A laser scanning optical device of the present invention irradiates a rotating polygon mirror through a lens system with laser light generated from a laser diode, and deflects reflected light at a constant speed by an fθ lens. And form an image on the exposure surface,
In a laser scanning optical device used in an electrophotographic printer for scanning, a flexible printed circuit equipped with a laser diode and a synchronous sensor for injecting / detecting a part of the deflected light passing through the fθ lens, and a collimator holding a collimator lens. A lens frame, an aperture, and a laser diode mounted on the flexible printed circuit are inserted and adhered to one end face, and an aperture is inserted and adhered from the other end face to the collimator frame, and the flexible printed circuit and the collimator are attached. It is configured by having a cylindrical holder that integrates the lens frame and the aperture, and in this configuration, a guide pin and a screw tightening hole for mounting the holder on a plane on which the fθ lens and the polygon motor are mounted. The chassis that it has, and the guide pins and And a holder having a mounting hole having a guide hole corresponding to the mounting screw hole and the screw hole.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a plan view showing the structure of an embodiment of the present invention. In the embodiment of FIG. 1, a laser diode unit (hereinafter, referred to as an LD unit) 1 in which a collimator lens, a flexible printed circuit having a laser diode and a synchronous sensor 7 attached (hereinafter, referred to as FPC) are integrated, a correction lens 12, and a polygon. A polygon mirror 13 attached to a motor 14 and an fθ lens including an fθ first lens 15 and an fθ second lens 16 are mounted on a chassis 11.

FIG. 2 is an exploded perspective view of the LD unit 1 used in FIG. The LD unit 1 is a flexible printed circuit board with a laser diode 6 and a synchronous sensor 7 attached to it.
PC 5, laser diode holder (hereinafter referred to as LD holder) 2, collimating lens frame 3, and aperture 4
The laser diode 6 is inserted and adhered to one end face concave portion of the LD holder 2, the collimating lens frame 3 and the aperture 4 are inserted from the other end face of the LD holder 2, and the laser diode 6 is provided on the top face portion of the LD holder 2. It is designed to be glued using a notch.

FIG. 3 is a perspective view of an LD unit mounting structure. The LD unit 1 is positioned by the guide pin 9 provided on the plane of the chassis 11 and attached to the screw tightening hole 10 by the screw 8.

FIG. 4 is a cross-sectional view including the LD unit 1 of FIG. 1, in which the fθ first lens 15 and the fθ second lens 16 as well as the LD unit, the correction lens, and the polygon motor to which the polygon mirror is attached are all in the chassis 11. It is shown that it can be mounted on a flat surface.

[0011]

As described above, according to the present invention, an LD unit having a laser diode, a collimating lens and an aperture mounted on a flexible printed circuit board is integrally mounted on a chassis positioned by a guide pin from a vertical direction. By doing so, there is almost no need to adjust the optical axis at the time of assembly, and there is an effect that assembly and inspection can be significantly reduced. Further, since the laser diode and the synchronous sensor are attached to the flexible printed circuit board and added to the LD unit, there is an effect that the device can be downsized.

[Brief description of drawings]

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

FIG. 2 is an exploded perspective view of an LD unit used in the embodiment of FIG.

FIG. 3 is a perspective view of a mounting structure of the LD unit of FIG.

FIG. 4 is a cross-sectional view including the LD unit of FIG.

FIG. 5 is a cross-sectional view of a conventional laser diode and collimating lens portion.

FIG. 6 is an exploded perspective view of a conventional laser diode and a collimating lens portion.

[Explanation of symbols]

 1 Laser diode unit (LD unit) 2 Laser diode holder (LD holder) 3 Collimating lens frame 4 Aperture 5 Flexible printed circuit (FPC) 6 Laser diode 7 Synchronous sensor 9 Guide pin 10 Screw tightening hole 11,21 Chassis 12 Correction lens 13 polygon mirror 14 polygon motor 15 fθ first lens 16 fθ second lens 22 A housing 23 B housing 24 printed circuit board

Claims (2)

[Claims] 1. An electrophotographic printer which irradiates a polygon mirror rotating through a lens system with laser light generated from a laser diode, deflects reflected light at a constant speed by an fθ lens, and forms an image on an exposure surface for scanning. In a laser scanning optical device used for a laser beam, a flexible printed circuit equipped with a laser diode and a synchronous sensor for detecting and entering a part of the deflected light passing through the fθ lens, a collimating lens frame for holding the collimating lens, and an aperture. A laser diode mounted on the flexible printed circuit is inserted and adhered to one end face, and an aperture is inserted and adhered from the other end face to the collimator frame, and the flexible printed circuit, the collimator lens frame, and the aperture are attached. And a cylindrical holder which integrates the laser scanning optical device. 2. The laser scanning optical device according to claim 1, wherein a chassis having guide pins and screw fastening holes for mounting the holder on a plane on which the fθ lens and the polygon motor are mounted, and the holder are provided on the chassis. And a holder having a mounting base having a guide hole and a screw hole corresponding to the guide pin and the mounting screw hole.