JPH03194511A - optical equipment - Google Patents

Abstract

PURPOSE:To easily fix a lens to be used for an optical system at a low cost and to facilitate the exchange of only the lens by using a coil spring of a simple shape which is an elastic body as a fixing member to fix the optical member. CONSTITUTION:An ftheta lens 92 has projections 96 which facilitate the positioning to a reference position. A housing 10 is disposed with hooks 22 and mounting bases 24 to be bridged with the coil spring 30 for fixing the lens 92 by integral molding or screwing, etc. The projections 96 of the lens 92 are inserted into positioning holes 26, 28 disposed on the reference face 20 of the housing 10 and the base of the lens 92 is brought into surface contact with the reference face 20. The lens 92 is exactly pressed and fixed to the prescribed position of the reference face 20 by the fixing spring, i.e. the coil spring 30 which is bridged in the spring receiving parts 98 of the lens 92. Since the fixing means is the coil spring, the easy exchange of the lens 92 is possible at the time of exchanging the lens.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention relates to an optical device used in an image forming apparatus such as a laser printer, in particular, to a lens group and an optical The present invention relates to an imaging optical device that guides a scanning object through a deflection device.

(Prior Art) In general, an optical device incorporated in a device such as a laser printer that uses an electrophotographic process as an image visualization means includes a light source that generates a light beam modulated according to a recording signal, a collimating lens system that adjusts the tip beam into a desired shape; a light deflection device that reflects the light beam onto an information recording medium such as a photoreceptor; lens group) and second (f
It is equipped with an imaging optical system (θ lens, etc.).

A light beam generated from a light source is guided through a collimating lens to a light reflector, ie, a light deflection device, and is reflected by the light deflection device at a constant angular velocity.

The light beam from the optical deflection device is imaged onto an object to be scanned, such as a photoreceptor, by first and second imaging optical systems. This light beam is imaged on the surface of the object to be scanned through first and second imaging optical systems arranged between the rotating polygon mirror composed of an fθ lens and the like and the object to be scanned.

In the optical device described above, the lenses used in the first and second imaging optical systems are fixed with an adhesive or a leaf spring.

(Problems to be Solved by the Invention) When an adhesive is used to fix the lens as described above, the adhesive requires time to dry, resulting in a loss of working time, and the device must be stored for drying. A place is required. Furthermore, if the lens needs to be replaced due to misalignment or damage to the lens, there is a problem in that the entire optical device must be replaced.

On the other hand, when a leaf spring is used to fix the lens, the shape of the leaf spring becomes complicated, the cost of the spring increases, and the pressure must be controlled to prevent lens displacement and pressing. There are problems that complicate the work.

An object of the present invention is to provide an optical device in which lenses used in the optical device can be fixed simply and at low cost, and in which only the lenses can be easily replaced.

[Structure of the Invention] (Means for Solving the Problems) This invention has been made based on the above-mentioned problems, and includes an optical stage for guiding a light beam to an object to be scanned, and a standard for fixing this optical stage. An optical device is provided, comprising: a surface; and an elastic body for press-fixing the optical means to the reference surface.

Further, the optical means for guiding the light beam to the object to be scanned, a housing means integrally formed with a reference surface for accommodating the optical means and identifying the optical means, and an elastic member for pressing and fixing the optical means to the reference surface. Provided is an optical device comprising: a body;

(Function) According to the present invention, when fixing an optical member incorporated into an optical device, a fill spring having a simple shape is used, and the optical member is fixed accurately and reliably. Furthermore, since the fixing means is a coil spring, the optical member can be easily replaced when replacing it. Furthermore, since the reference position for fixing the optical member is integrally formed with the accommodation means for accommodating the optical means, the number of parts is reduced, and assembly errors due to accumulation of differences between parts are reduced. .

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

1 to 3 schematically show an optical apparatus in which the lens internal determination method of the present invention is utilized. FIG. 1 is a schematic diagram showing the optical device with the bottom cover removed;
Fig. 2 is a schematic diagram showing the inside of the optical device shown in Fig. 1 with the electrical components removed, and Fig. 3 is an external appearance of the optical device shown in Fig. 1 viewed from the bottom side. It is a schematic diagram.

The optical device or exposure unit 2 includes a housing IO integrally molded from black plastic. As shown in FIG. 1, the entire lower surface of the housing IO is formed as an opening, and is shielded by a bottom plate 12, which also serves as a shield member, as shown in FIG. The bottom plate 12 is fixed by screws 36 into screw holes 38 such as embedded nuts embedded in the housing 10 .

The housing IO includes a semiconductor laser element 50, a laser drive circuit 52 that drives the laser, a light deflection device that scans an object with a light beam, that is, a polygon mirror 70, and a polygon mirror drive circuit 7 that drives this polygon mirror.
2, and '1 for electrical parts such as lasers or optical deflection devices.
It is equipped with a printed circuit board 42 that supplies 4R. Also,
The housing IO includes a collimating lens 60 for collimating the light beam from the laser 50, a first imaging lens system 80 having a first fθ lens, and first and second mirrors for folding the optical path, and a scanning target (not shown), i.e. A second imaging lens system 90 having a second fθ lens 92 and a dustproof glass 94 that image the forward beam onto the image plane of the photoreceptor, and a housing section 14 that accommodates the second imaging lens system 90. There is.

On the other hand, a slit-shaped opening 16 is formed on the upper surface of the housing IO to guide a light beam to a scanning target (not shown), ie, a photoreceptor, via a second imaging lens system 90. This slit-shaped opening 16 is connected to the dust-proof glass 9 of the second imaging lens system.
4, and a cover 18 blocks ambient light.

4A and 4B show a method of fixing a lens incorporated in the optical device shown in FIGS. 1 to 3. Figure 4A is a schematic diagram of how to fix the lens, Figure 4B
The figure is a sectional view at the lens fixed position.

As is clear from FIG. 4B, the lens (here, the second fθ lens 92 will be explained as an example) includes a protrusion 96 that facilitates positioning with respect to the reference position. Also,
A hook 22 to which a coil spring for identifying the lens 92 is bridged, and a mounting base 24 are disposed in the housing 10 by integral formation, screwing, or adhesion.

The protrusion 96 of the lens 92 is aligned with the reference surface 20 of the housing lO.
The bottom surface of the lens 92 is in surface contact with the reference surface 20 of the housing. The positioning holes 26 and 28 are designed such that one or both of them are long in the optical axis direction of the reference surface 20 of the housing in order to facilitate the insertion of the lens 92 and to loosen the spacing accuracy of the protrusions 96 provided on the lens 92. formed into a hole.

The lens 92 is attached to the housing l by a fixed spring or coil spring 30 bridged to the spring bearing part 98 of the lens 92.
It is pressed and fixed accurately to a predetermined position on the reference surface 20 of O with a simple structure.

FIG. 5 shows another embodiment of the lens fixing method of the present invention shown in FIGS. 4A and 4B.

According to FIG. 5, the hook 2 arranged in the housing lO
2 has a groove or recess 32 in which the coil spring 30 is bridged.
is located. Therefore, the positional deviation of the coil spring 30 bridged to the lens 92 in the main scanning direction parallel to the reference plane 20 is eliminated, and the lens 92 can be fixed more stably.

In the embodiment of the present invention shown in FIGS. 4A to 5 described above, an example was shown in which the lens 92 is fixed.
Needless to say, it can be used for general optical members such as mirrors and second mirrors.

FIG. 6 shows a cross section of the optical device shown in FIGS. 1 to 3 at a deflection angle of 0'' in the sub-scanning direction.

The housing 10 includes a printed circuit board 40 that supplies power to electrical components such as a laser or an optical deflection device, a laser drive circuit 52 and a laser 50 arranged on this board, a polygon mirror drive circuit 72 and a polygon mirror 70, and a laser 5.
0'' and the polygon mirror 70 (this figure is not visible because it is a cross section with a deflection angle of 0''), and a first imaging lens system 80 and a second imaging lens system 90. That is, in the housing IO, a first fθ having positive power in both the main scanning direction and the sub-scanning direction is arranged to focus the light beam on the recording surface of the photoreceptor.
The lens 82 has a shape that satisfies h-fθ, which is combined with the power of the first fθ lens in the main scanning direction and makes the image height proportional to the rotation angle θ of the reflective surface, and the first fθ lens in the sub-scanning direction. A second fθ lens 92 and a dustproof glass 94, which are combined with the power of the lens and given power to focus a light beam on the surface of the photoreceptor, are arranged, and combined with the first mirror 84 and the second mirror 86, A light beam passing region 34 is formed.

The operation of the light beam generated by the laser 50 will be explained using FIG. 6. The leading beam of the laser 5o of the laser drive circuit 52 disposed on the printed circuit board 4o is adjusted into a predetermined beam shape via the collimating lens 6o, and is scanned in the main scanning direction by the reflective surface 74 of the polygon mirror 70. The light beam from the polygon mirror 70 is focused in both the main scanning direction and the sub-scanning direction by the first fθ lens 82 of the first imaging lens system 8o, and is guided to the first mirror 84. This light beam is reflected by the first mirror 84 toward the second mirror 86 . The light beam reflected again by the second mirror 8B is transmitted to the second f of the second imaging lens system 9o.
The polygon mirror 7 is rotated in the main scanning direction by the θ lens 92.
The image height is proportional to the rotation angle θ of the reflective surface 74 of zero, and the image is focused in the sub-scanning direction to a predetermined position on the surface of the photoreceptor, and the photoreceptor (not shown) is transmitted through the dust-proof glass 94. guided to the body.

(Effects) As described above, since a simple coil spring is used as the fixing member for fixing the optical member, the optical member is reliably and replaceably fixed to the container. Further, since the reference position for fixing the optical member is integrally formed with the housing means for housing the optical means, it can be fixed accurately using a coil spring of a simple shape. As a result, assembly errors due to the number of parts and the accumulation of tolerances between parts are reduced, and assembly efficiency is improved and costs are reduced.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing an optical device according to an embodiment of the present invention with the bottom cover removed, and Fig. 2 shows a state of the optical device shown in Fig. 1 with the electrical equipment removed. 3 is a schematic diagram showing the inside of the optical device shown in FIG. 1, FIG. 3 is a schematic diagram of the external appearance of the optical device shown in FIG. , a sectional view at the lens fixing position, FIG. 5 is a schematic diagram showing a lens fixing method according to another embodiment of the present invention, and FIG. 6 is a cross-sectional view of the lens fixing position.
FIG. 3 is a cross-sectional view showing the optical device shown in the figure at a deflection angle of 0° in the sub-scanning direction. 10...Housing, 20...Reference surface, 22...
Hook, 24...Mounting base, 30...Coil spring, 5
o...Semiconductor laser element, 52...Laser drive circuit, 70...Polygon mirror 72...Polygon mirror drive circuit, 84...Second mirror 92...Second fθ lens

Claims (2)

[Claims] (1) An optical system comprising an optical means for guiding a light beam to an object to be scanned, a reference surface to which the optical means is fixed, and an elastic body for pressing and fixing the optical means to the reference surface. Device. (2) An optical means for guiding a light beam to an object to be scanned, a housing means integrally formed with a reference surface for accommodating this optical means and fixing this optical means, and pressing and fixing the optical means to the reference surface. An optical device comprising an elastic body.