JPS62299832A - Scanning optical device - Google Patents

Abstract

PURPOSE:To control the angle of the reflecting surface of a reflecting mirror without using any gear mechanism by providing moving members which couple with the reflecting mirror and move the reflecting mirror at a specific speed on both sides of a scanning track straight line, fitting a support arm to the reflecting mirror, and moving this support arm along a guide member. CONSTITUTION:When a motor 23 is driven, the moving members 14 and 15 move through wires 17, 18, and 16. Then, the reflecting mirror 6 moves while sliding on the linear guide member 9 provided on the scanning track straight line XX'. At this time, the support arm 10 fixed to the support member 8 of the reflecting mirror 6 slides on the guide member 12 and then the reflecting surface of the reflecting mirror 6 varies gradually in inclination as it moves in a scanning direction. Then, the reflecting mirror 6 is slid on the scanning track straight line XX' at a proper scanning speed so that no step-out state is caused on a reproduced image.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Industrial Field of Application) In the present invention, the beam-forming printer or the like uses the imaging light between the imaging lens and the virtual imaging surface to a predetermined position on the photoreceptor. The present invention relates to a scanning optical device that performs optical scanning by rotating or moving one reflective mirror so as to guide the mirror to a position.

(Prior Art) Conventionally, this type of device that performs optical scanning using only one reflecting mirror is disclosed in Japanese Patent Application Laid-Open No. 55-126258 and US Pat. No. 4,299.480. In such a conventional example, as the reflecting mirror moves to the virtual imaging point, the reflecting surface of the reflecting mirror moves while matching the perpendicular bisector of the line segment connecting the virtual imaging point and the exposure position. Therefore, optical scanning was performed.

That is, in order to perform optical scanning in the conventional example, as shown in FIG.
A reflective mirror 106 is disposed approximately midway between the photosensitive drum 107 and a point on the virtual image forming surface 105 and an image forming point on the photosensitive drum 107 in synchronization with the rotational speed of the photosensitive drum 1070. Connect J: Reflection mirror 1 on the perpendicular bisector of the line segment
Since the reflective surface of 06 needs to move while matching,
The trajectory of the reflecting mirror 106 becomes a curve SS'.

However, in such conventional examples, the scanning optical device for moving the reflecting mirror connects (links) the reflecting mirror to a portion of the lens corresponding to the pupil position or the exposure position on the photosensitive drum using a sliding connecting member. Since the device is configured to be moved by
There is a problem in that the free width of the actual optical arrangement is reduced.

As a conventional means for solving this problem, there is Japanese Patent Application No. 61-109604 filed by the present applicant. In such a conventional example, a reflection mirror placed at an arbitrary position that can be scanned between an imaging lens and an imaging surface is moved on a straight trajectory inclined with respect to the virtual imaging surface while changing the reflection surface. By doing so, the passing image of the object on the microphone film is sequentially transmitted, and the image is formed on a photosensitive drum rotating at a constant speed at a fixed position, thereby performing optical scanning.

(Problems to be Solved by the Invention) By the way, in the above-mentioned conventional example, Japanese Patent Application No. 109604/1983, a scanning device for scanning is provided on a straight line of the scanning trajectory of a reflecting mirror or on a straight line parallel thereto. The angle of the reflective surface of the reflective mirror is controlled by a deceleration mechanism consisting of a rack and a series of ears that mesh with the rack, so the reflective surface requires precise precision due to the backlash of each gear. There are problems such as an error in the angle of the gear, causing synchronization, and a large reduction ratio, which increases the diameter of the gear and the number of gears, making the device larger and more complex. there were.

In addition, in the conventional example, the prerequisite is that the reflecting mirror moves at an approximately constant speed on the straight line of the scanning trajectory that is set only when the slope of the straight line is relatively small. Naturally, this method is not effective when the slope of the scanning trajectory straight line is large. In such a case, it is possible to use a pulse motor as the motor for driving the scanning device and change the rotational speed of the motor electrically to change the moving speed of the reflecting mirror. Generally, when a pulse motor is used as a drive motor, some rotational unevenness will occur depending on the pulse rate and load characteristics, and this rotational unevenness will have a subtle effect on the movement of the reflecting mirror, causing distortion in the reproduced printed image. There was a point.

Therefore, the present invention has been made to solve the above-mentioned problems of the conventional example, and its purpose is to control the angle of the reflective surface of the reflective mirror without using a gear mechanism, and to perform scanning. Regardless of the slope of the trajectory line,
The objective is to appropriately control the speed of the reflecting mirror in a straight line.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, one reflective mirror disposed between the imaging lens and the imaging surface is aligned with the scanning trajectory straight. In a scanning optical device that performs optical scanning by moving along a straight line, a moving member is provided on both sides of the straight line of the scanning trajectory to connect with the reflecting mirror and move the reflecting mirror at a predetermined speed, and the moving member is supported by the reflecting mirror. It is constructed by attaching an arm and moving the supporting arm along a guide member to control the angle of the reflecting surface of the reflecting mirror.

(Function) In the present invention having the above configuration, moving members are provided on both sides of the straight line of the scanning trajectory to connect with the reflecting mirror and move the reflecting mirror at a predetermined speed, so that the reflecting mirror can be scanned at an appropriate scanning speed. And by attaching a support arm to the reflecting mirror and moving this support arm along the guide member,
This makes it possible to control the angle of the reflective surface of the reflective mirror without using a gear mechanism.

(Example) The present invention will be explained below based on the illustrated example. 1st
2 and 2 are schematic diagrams for explaining the principle of an embodiment of the scanning optical device according to the present invention, and in the same figure, 1
is an illumination lamp, and the light emitted from the illumination lamp 1 is
The microfilm 3 is irradiated through the condenser lens Je2, and the image of the microfilm 3 is projected onto the virtual imaging plane 5 through the imaging lens 4.

In this case, on the display surface of the microfilm 3, the second
As shown in the figure, the point B on the optical axis of the lens 4 and the points on both sides of it and C are the respective points B1 and A on the virtual imaging plane 5,
A reflecting mirror 6 is disposed approximately midway between the lens 4 and the virtual image forming surface 5 to reflect the image forming light and form an image on the surface of the photosensitive drum 70. In order to
It is necessary to make the distance from the image forming point of the photosensitive drum equal to the distance from the image forming point of the photosensitive drum.

Therefore, in order to perform optical scanning, the reflecting mirror 6 is synchronized with the rotational speed of the photosensitive drum 70, and the virtual image forming surface 5 is
Since the reflection surface of the reflection mirror 6 must match the perpendicular bisector of the line segment connecting the upper point and the imaging point on the photosensitive drum 7 while moving, the trajectory of the reflection mirror 6 follows the curve SS '. The shape of this curve SS' varies depending on the placement position of the photosensitive drum 7, but as shown in FIGS. 1 and 2,
The position of the reflecting mirror 6 is relatively close to the lens 4,
When the position of the photosensitive drum 7 is far from the virtual imaging plane 5 and close to the lens 4, the curve SS
′ can be regarded as a substantially straight line. Therefore, a method can be considered in which scanning is performed by moving the reflecting mirror 6 on a linear trajectory. At this time, in order to form images of the light that has passed through the lens x'4 on the photosensitive drum 7 at all positions in the image area on the linear trajectory, the photosensitive drum rotates at a constant speed while rotating the angle of the reflection T-boo 6. 7, it is necessary to scan while changing the moving speed.

In determining the actual linear trajectory, for a curved trajectory equation that does not cause an optical path difference, a linear regression line that takes the minimum optical path length deviation at an arbitrary position is used as the scanning trajectory line. do. In general, projection lenses for microfilm used in reader printers, etc., have advantages such as a narrower angle of view and a deeper recess than lenses used in copying machines, etc. There is almost no effect of optical path deviation.

Figure 3 shows a scanning trajectory line XX' shown in Figure 2 that passes through a point 650m+ on the optical axis from the virtual image plane 5 and has an inclination of 12.5° with respect to the virtual image plane. The horizontal axis represents the movement displacement of the reflecting mirror 6 on the scanning trajectory straight line XX', and the vertical axis represents the angular displacement of the angle that the reflecting surface of the reflecting mirror 6 makes with the scanning trajectory straight line XX'. Here, the reflective surface of the reflective mirror 6 coincides with the scanning trajectory straight line XXl. Further, as is clear from the figure, the movement displacement and angular displacement of the reflection mirror 6 are in a linear proportional relationship, and the reflection surface changes according to the movement displacement of the reflection mirror 6 in the scanning direction on the scanning trajectory sxx'. It will rotate by a certain angle in a certain direction. Note that points a and a shown in FIG. 2 are the intersections of lines A, , C, which form part of the optical path, and the scanning trajectory straight line XX', and the area between 116 and 116 is the effective scanning area.

Next, FIG. 4 shows a driving system for a reflecting mirror in an embodiment of the scanning optical device according to the present invention.
9 is a linear guide member, 10 is a support member 8
11 is a slider attached to the tip of the support arm 10, and 12 is a straight line on which the slider 11 slides.
fm (or curved) shaped guide member, 13 is a reflecting mirror 6
a linear guide member on which a rotating shaft 6 & can slide;
4゜15 is a moving member attached to the guide member 13 and moves in parallel; 16 is a wire wound around the boos IJ 19 and 20; 17 is a wire wound around pulleys 21 and 22; 18 is a moving member wound around the pulleys 20 and 22. Wrapped V
This is a motor for rotationally driving the 23-wheel pulley 21.

In the above configuration, driving the motor 23 causes the moving member 14.15 to move via the wires 17.18 and 16. Then, the reflecting mirror 6 moves while sliding on a linear guide member 9 provided on the scanning trajectory straight line xx' shown in FIG. At that time, the support member 8 of the reflecting mirror 6
By sliding the supporting arm 10 fixed to the guide member 12, the inclination of the reflecting surface of the reflecting mirror 60 gradually changes as it moves in the scanning direction. In this embodiment, the shapes and positions of the support arm 10 and guide member 12 are determined so as to satisfy the relationship shown in FIG.

Further, the scanning trajectory straight line XX' is not parallel to the virtual imaging plane 5, but has an inclination. Therefore, the virtual imaging plane 5
The equal pitches shown above become unequal intervals in the scanning image area of the reflecting mirror 6, and if the reflecting mirror 6 were to move at a constant speed on the scanning image area, the moving amount would be different between each pitch, so it would not move at a constant speed. This causes a synchronization shift in the reproduced image with respect to the photosensitive drum 7 which rotates. Therefore, the reflection mirror 6 needs to be moved with increasing speed as it approaches the virtual image plane 5 in the scanning direction.

However, due to the geometric similarity condition, in the direction parallel to the virtual image forming surface 5, at any position, the speed is proportional to the moving speed of the virtual image forming surface 5, that is, the rotational circumferential speed of the photosensitive drum 7. It becomes a constant speed.

Therefore, in this embodiment, the moving member 14.15 is moved to the upper and lower positions via the scanning trajectory straight line XX' by the wire 16°17.1.
8 and pulleys 19, 20, 21 and 22 in a direction parallel to the virtual imaging plane 5 at a constant speed according to each setting position, the moving members 14, 15 are connected and the guide path is Although a guide groove 12a is formed as a
Slide on X' at an appropriate scanning speed.

FIG. 5 is a diagram showing the scanning principle of the reflecting mirror in this embodiment, in which straight lines PP' and QQ' parallel to the virtual imaging plane 5 are provided on both sides of the scanning trajectory straight line XX'. Points Bt, Bs, and B are each a scanning trajectory straight line xx'.

Points on the straight lines p p/ and Q Q/ indicate the set positions of these straight lines on the optical axis. Further, V is the moving velocity vector of the virtual imaging plane 5, and Vp + VQ and V are the direct MPP', QQ', and XX' corresponding to the velocity vector V, respectively.
is the velocity vector above. In the same figure, from the triangle similarity condition, Vp: VQ: vxLBs: LB4: L
B, = I, :L* : has been done. Here, LH+
LH and L are distances from the pupil point of the imaging lens 4, respectively.

Therefore, Boo') 19 e
20 and the diameter of the boo IJ 21, 22 or the drive motor 2
If the rotation speed of 3 is determined, V
The size of the workpiece can be obtained.

In the above embodiment, the control of the reflection mirror was explained when the scanning trajectory straight line XX' was set at a certain specific position, but the control is not limited to this, even if the scanning trajectory straight line XX' is set at a different position. Appropriate angle control can be obtained by changing the shape and setting position of the guide member 12 so as to satisfy the movement of the reflecting mirror at that time. Further, in the above embodiment, appropriate speed control can be obtained by changing the diameters and set positions of the pulleys 19, 20 and pulleys 21, 22.

In the above embodiment, in order to control the angle of the reflecting surface of the reflecting mirror 6, the supporting arm 10 is attached to the supporting member 8 of the reflecting mirror 6, and the slider 11 of this supporting arm 10 slides on a straight line or a curved line. By providing the shaped guide member 12t, accurate and stable continuous displacement of the reflecting mirror 6 can be obtained with a simple configuration.

In addition, in the above embodiment, by using a drive motor that rotates at a constant speed, no matter what position or inclination the scanning trajectory straight line is set, as long as it is a range concavity that can be scanned linearly. , it becomes possible to scan the reflecting mirror at an appropriate scanning speed, and it becomes possible to increase the degree of freedom in setting the scanning trajectory straight line.

(Effects of the Invention) The scanning optical device according to the present invention has the above-described configuration and function, and can control the angle of the reflecting surface of the reflecting mirror without using a gear mechanism, thereby making the device compact and simple. be able to. In addition, it is possible to appropriately control the speed of the reflecting mirror regardless of the inclination of the scanning trajectory straight line.
As a result, a clear reproduced print image can be obtained.

[Brief explanation of the drawing]

1 and 2 are schematic diagrams for explaining the principle of an embodiment of the scanning optical device according to the present invention, and FIG. 3 shows the displacement of the reflecting mirror on the straight line of the scanning trajectory and the reflection at that time in the same embodiment. FIG. 4 is a front view showing the scanning drive system of the reflecting mirror in the same embodiment; FIG. 5 is a diagram showing the principle of scanning of the reflecting mirror in the same embodiment; FIG. 6 is a schematic diagram for explaining the principle of an example of a conventional scanning optical device. Explanation of symbols 4...Imaging lens 5...Virtual imaging surface 6...
・Il club 10...Support arm 12...Guide member 12a...Guide groove (
Guide path) 14.15...Moving member

Claims (4)

[Claims] (1) In a scanning optical device that performs optical scanning by moving one reflective mirror disposed between an imaging lens and an imaging surface along a scanning trajectory straight line, A moving member is provided that connects with the reflecting mirror and moves the reflecting mirror at a predetermined speed, and a support arm is attached to the reflecting mirror, and the supporting arm moves along a guide member to improve the reflection of the reflecting mirror. A scanning optical device characterized by controlling the angle of a surface. (2) The movable member is arranged at distances L_1 and L_2 from the pupil point of the imaging lens, and moves parallel to the imaging plane arranged at the distance L. The scanning optical device according to item 1. (3) The moving member is L_1/with respect to the photosensitive drum rotating at a circumferential speed V by a wire and pulley driving means.
3. The scanning optical device according to claim 1, wherein the scanning optical device moves at a speed of LV and L_2/LV. (4) The scanning optical device according to claim 1, wherein the guide member has a linear or curved guide path that is non-parallel to the scanning trajectory line.