JPH0475015A - Lens adjusting device of scanning optical device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lens adjustment mechanism for a scanning optical device, and more particularly to a lens adjustment mechanism for a scanning optical device that can improve positioning accuracy during adjustment work.

[Conventional technology]

Scanning optical devices used in laser printers, laser facsimiles, etc. scan the light beam generated from a light source using an imaging optical system and a deflector. , a high degree of positioning accuracy is required when installing the lens of the imaging optical system.

The conventional lens adjustment mechanism of this type of scanning optical device is as follows.
For example, there is one described in JP-A-1-321421. In this device, a lens group for correcting surface tilting is provided between a light source section and a light deflecting section, and a holder for holding the lens group for correcting surface tilting is attached to a housing on a base plate. It is mounted so that it can be displaced in the optical axis thrust direction and radial direction, and the focal point position of this lens group is adjusted.

Furthermore, Japanese Utility Model Application Publication No. 2-19161 discloses that a lens holder of an imaging optical system is positioned by the biasing force of a spring, and a lever-like jig that engages with this lens holder and a guide section that guides the lens holder. A lens holder is described in which the lens holder is movable and adjustable along the optical axis.

[Problem to be Solved by the Invention] However, in the former conventional lens adjustment mechanism of the scanning optical device, the holder of the lens group for correcting surface tilt can be displaced in the optical axis direction and the radial direction through the through hole of the housing. Because the lens was attached to the holder in the thrust direction, the optical axis would shift due to play between the holder and the through hole when the holder was displaced in the thrust direction, making it difficult to adjust. There was a problem in that it was difficult to position the lens on the optical axis.

In addition, in the conventional lens adjustment mechanism of the latter scanning optical device, the holder positioning and holding mechanism is located away from the optical axis, which causes the overall size to increase.
There was a problem in that the rotation could not be adjusted, and when moving in the optical axis direction, displacement or inclination would occur due to play between the groove and the engaging portion.

(Purpose of the Invention) Therefore, the present invention provides a structure in which the holder is supported rotatably around its center axis and movably in the direction of the center axis while the axis of the holder is positioned on the optical axis, so that the holder is supported during adjustment work. The object of the present invention is to provide a lens adjustment mechanism for a scanning optical device that allows easy and reliable positioning of the lens, and also to make the structure simple and compact.

[Means to solve the problem]

In order to achieve the above object, the present invention is provided in a scanning optical device that optically scans a light beam generated from a light source using an imaging optical system and a deflector. A holder that holds the optical axis or focal point of the lens of the imaging optical system substantially aligned with the central axis of the circumferential surface portion, and a holder that engages with the circumferential surface portion of the holder and is rotatable around the central axis of the circumferential surface portion. and a base that supports the holder movably in the direction of the central axis; and biasing means that biases the holder against the base to position the axis of the holder on a predetermined optical axis; , in order to simplify its configuration, the base is
It is characterized by having a V-shaped groove that engages with the circumferential surface of the holder.

Hereinafter, the present invention will be explained based on examples.

1 to 3 are diagrams showing an embodiment of the lens adjustment mechanism of the scanning optical device according to the present invention. FIGS. 1 and 2 show the lens adjustment mechanism, and FIG. 3 shows the entire scanning optical device. Illustrated.

In FIGS. 1 to 3, reference numeral 11 denotes a light source unit attached to the support 1o and generating a luminous flux. The light beam generated by the light source section 11 passes through the lens 12 constituting the imaging optical system, reaches the deflector 13, is deflected and reflected by the deflector 13, and is f
After passing through the θ lens 14, it is deflected by a folding mirror 15 and reaches a photoreceptor (not shown) (third
(see figure).

As shown in FIG. 1.2, the lens 12 is supported by a holder 21 which has a circumferential surface part 22 in a part of its outer shape, and the holder 21 allows the optical axis or focal point of the lens 12 to be set at the center of the circumferential surface part 22. It is designed to be held in line with the axis. This holder 21 has a base 23 provided integrally with the support io.
The base 23 has a square groove 24 extending parallel to a predetermined optical axis direction. This base 23 is V
A pair of slopes 25.2G of the mold groove 24 engage with the circumferential surface portion 22 of the holder 210, supporting the holder 21 so as to be rotatable around the central axis of the circumferential surface portion 22 and movable in the direction of the central axis of the bracket. . Further, a long hole 27 is formed in the holder 21 at a position opposite to the lower part of the V-shaped groove 24, and a stepped screw 2, which is threadedly connected to the base 23, is inserted into the long hole 27 in a predetermined radial direction. It is inserted with enough allowance. This stepped screw 2
Disc springs 31 and 32 as biasing means are installed between the 8 and the periphery of the elongated hole 27 of the boulder 21, and these disc springs 31 and 32 bias the holder 21 against the base 23. can be positioned on the optical axis. That is, the holder 21 is positioned on the ■-shaped groove 24 of the base 23 so as to be coaxial with the optical axis under the urging force of the disc springs 31 and 32, and in this state can slide on the base 23 along the optical axis. It is. Note that the holder 21 is inserted into the ■-shaped groove 2 of the base 23.
A compression spring or the like can be used as the biasing means for biasing the pressure 4, but if you try to obtain a pressing force of 10 kgf or more, the length of the spring becomes long, so disc springs, leaf springs, etc. are made more compact. It is advantageous for

On the other hand, the holder 21 is provided with a protruding arm part 33 that protrudes in a direction perpendicular to the axis of the circumferential surface part 22 . ) or are connected to the brackets provided on the sides thereof so as to abut against each other. These protruding arm portions 33 and screws 34 change the thread length below the protruding arm portion 33 by rotating the screw 34, and tilt the upper part of the holder 21 slightly to the side on the base 23 (the holder 21).

According to such a configuration, the holder 21 is connected to the disc spring 31.3.
The holder 21 is positioned in the ■-shaped groove 24 of the base 23 so as to be coaxial with the optical axis by the biasing force of 2, and the holder 21 can be slid on the base 23 along the optical axis in this state, and held in the holder 21. The positions of the lens 12 and the holder 21 in the optical axis direction can be adjusted while the lens 12 is positioned on the optical axis.

In addition, by simply rotating the screw 34 with a tool (not shown) engaged from above, the holder 21 can be slightly rotated around its axis, which allows the lens 12 to be aligned with the optical axis opening. The rotation can also be adjusted.

Therefore, it is possible to keep the optical axis or focal point of the lens 12 on a predetermined optical axis even during adjustment work, and to provide a lens adjustment mechanism for a scanning optical device that can easily and reliably position the lens during adjustment work. can do.

Furthermore, in this embodiment, the base 23 is
Since it has a ■-shaped groove 24 that engages with the circumferential surface portion 22 of 1,
A high degree of positioning accuracy of the holder 21 can be ensured while simplifying the configuration of the base 23, and a compact lens adjustment mechanism can be achieved.

〔effect〕

According to the present invention, the holder is biased against the base by the biasing means to position the lens on the predetermined optical axis, and the holder is slid in the predetermined optical axis direction or slightly rotated in the rotational direction. Since the position of the lens is adjusted, the optical axis or focal point of the lens can be kept on the predetermined optical axis even during adjustment work, and scanning allows easy and reliable positioning of the lens during adjustment work. A lens adjustment mechanism for an optical device can be provided.

Furthermore, if the base has a V-shaped groove that engages with the circumferential surface of the holder, a compact lens adjustment mechanism with a simple base configuration can be achieved.

[Brief explanation of drawings]

1 to 3 are views showing an embodiment of the lens adjustment mechanism of the scanning optical device according to the present invention, FIG. 1 is an exploded perspective view of the lens adjustment mechanism, and FIG. 2 is a cross-sectional view of the lens adjustment mechanism. 3 are external perspective views of the scanning optical device. 11... Light source section, 12... Lens (imaging optical system), 13...
...Deflector, 21...Holder, 22...Circumferential surface portion, 23...Base, 24...■Mold groove, 25.26... ...Slope (maintaining surface), 27...
...Elongated hole, 28...Stepped screw, 31.32...Disc spring (biasing means), 33...
...protruding arm, 34...screw.

Claims (2)

[Claims] (1) Provided in a scanning optical device that optically scans the light flux generated from a light source using an imaging optical system and a deflector. A holder that holds an axis or focal point aligned with the central axis of the circumferential surface portion; and a holder that engages with the circumferential surface portion of the holder so that the holder can rotate around the central axis of the circumferential surface portion and move in the direction of the central axis. A lens adjustment mechanism for a scanning optical device, comprising: a base that supports the holder; and biasing means that biases the holder against the base to position the axis of the holder on a predetermined optical axis. (2) The lens adjustment mechanism for a scanning optical device according to claim 1, wherein the base has a V-shaped groove that engages with a circumferential surface of the holder.