JPH0264579A - Optical device for copying machine - Google Patents

Abstract

PURPOSE:To reduce oscillation of a copying machine at the time of high-speed copying by moving a mobile mirror in the direction perpendicular to an original placing face to scan the surface of an original. CONSTITUTION:Movement of a lamp house 15, movement of a mobile mirror 14, and rotation of a photosensitive drum 20 and interlocked with one another, and the house 15 is moved in the direction of an arrow C and the mirror 14 is moved downward from above in the direction of an arrow D according as the drum 20 is rotated in the direction of an arrow B. Therefore, the house 15 is moved to a position 15a and a lens part 18 is moved to a position 18a when the mirror 14 is moved to a position 14a. At this time, an original image in a position 113 of an original 11 is irradiated by the house 15, and the image 113 is led to a fixed mirror 13 in the direction of an arrow D1a and is reflected in the direction of an arrow D2a and is reflected in the direction of the arrow D1a by the mirror 14a and is led to the drum 20 through the lens part 18a and the fixed mirror 19 and is formed on a photosensitive surface 21.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an optical device for a copying machine that scans and exposes an original image onto the photosensitive surface of a photosensitive drum.

<Prior Art> In a copying machine, it is necessary to perform scanning exposure of an original image on a photosensitive drum, so as shown in FIG. ,
A first movable mirror 84 that moves parallel to the document table 82 is provided integrally with the lamp house 83, and the light reflected by the first movable mirror 84 is transferred to a pair of second movable mirrors 84. Lens section 8 for imaging using mirrors 85 and 86
7 and passes through the lens section 87 to the fixed mirror 88.
By reflecting the image of the original 81 on the photosensitive drum 89
The structure is such that it is connected to the photosensitive surface of.

<Problems to be Solved by the Invention> In the copying machine described above, the original 81 is scanned by moving the first movable mirror 84, but when the first movable mirror 84 moves, the original 81
Since the distance from to the lens section 87 will change,
In order to compensate for the change in length, a second movable mirror 85
．． By moving mirror 86 at half the speed of first movable mirror 84, the length of optical path 91 is kept unchanged.

This means that the first movable mirror 84 and the second movable mirror 85,86 must move in the same direction, and in order to increase the speed of copying, the first and second movable mirrors When trying to move the mirrors 84 to 86 at high speed, at the beginning of the movement of these mirrors,
The increase in reaction force associated with the start of the movement has caused a problem in that the copying machine vibrates significantly in the horizontal direction.

The present invention was created to solve the above-mentioned problems, and its purpose is to provide an optical device for a copying machine that can reduce the vibrations of the copying machine that occur when copying is performed at high speed. It is in.

Means for Solving the Problems> In order to solve the above problems, an optical device of a copying machine according to the present invention has an optical device that is perpendicular to the document placement surface of the document table and directed downward from the document table. When the first direction is a direction parallel to the document placement surface and the second direction is a direction parallel to the document placement surface, a fixed mirror that reflects light from the document directed in the first direction in the second direction; A movable mirror that reflects the light reflected in the second direction in the first direction, and an optical path connecting the document surface and the photosensitive surface of the photosensitive drum, and moves together with the movable mirror. The scanner is equipped with a lens unit that forms an original image on the photosensitive surface of the photosensitive drum, and is configured to scan the original surface by moving a movable mirror in a direction perpendicular to the original placement surface.

A fixed mirror that reflects light directed in a first direction from an original in a second direction is fixed even during scanning exposure of the original, and the light reflected in the second direction by this fixed mirror is The movable mirror that reflects the image in the first direction is integrated with the lens section and moves in the direction perpendicular to the document placement surface as the scanning exposure scans, so the distance of the optical path from the document to the lens section is , at the center point of the optical path at each scanning position, the distance from the document to the fixed mirror in the first direction, the distance from the fixed mirror to the movable mirror in the second direction, and the distance from the movable mirror to the lens section in the first direction. It is the sum of the three types of distances with the distance in the direction of .

Therefore, when the center of the optical path moves due to the movement of the movable mirror, the change in the distance from the document to the fixed mirror in the first direction due to this movement is equal to the distance in the second direction from the fixed mirror to the movable mirror. Therefore, the distance from the document to the lens unit remains a constant distance even when the scanning position is moved.

<Embodiment> FIG. 1 is a schematic diagram showing the configuration of a first embodiment of the present invention.

In the figure, the main part is made of transparent glass, and near the lower part of the document table 12 on which the document 11 is placed horizontally on the document placement surface 121, the document table 12 is moved by a drive device (not shown).
A lamp house 15 is provided which moves parallel to the lamp.

Then, light from the original 11 emitted in a first direction Di that is perpendicular to the original placing surface 121 and directed downward from the original placing surface 121 is directed in a direction parallel to the original placing surface 121. The fixed mirror 13 that reflects in the second direction D2 is
Below the lamp house 15, there are four
It is set at an angle of 5 degrees. This fixed mirror 13 is
When viewed from the vertical direction (indicated by arrow A), document 1
The mirror is designed to be longer than the length required for one scan.

On the side where the light from the original 11 is reflected by the fixed mirror 13 and at a position away from the lower part 111 of the original 11, there is a
A mirror base 16 is provided which is guided vertically with respect to the document placement surface 121 by the slide shaft 17, and the mirror base 16 receives the light reflected in the second direction D2 by the fixed mirror 13. An elongated rectangular movable mirror 14 that reflects in the first direction D1 is attached.

The light reflected in the first direction D1 by the movable mirror 14 is reflected again in the second direction D2, thereby guiding the light from the document 11 to the photosensitive surface 21 of the photosensitive drum 20 (the fixed mirror 19 It is provided above the optical path connecting the movable mirror 14 and the photosensitive surface 21.
The lens section 18 for forming an image of on the photosensitive surface 21 is
In order to be located above the optical path and movable together with the movable mirror 14, it is attached to the mirror base 16 by a support fitting (not shown).

FIG. 2 is a plan view showing the detailed configuration of the mirror base 16.

Long rope mirror base 1 with movable mirror 14 attached
6 is provided with a sliding bearing 166 that moves along the slide shaft 17 in order to accurately move the mirror base 16 in a predetermined direction. On the side where the mirror 14 is attached, there is provided a joint between the mirror base 16 and a driving wire 165 provided for moving the mirror base 16.

Further, a freely rotatable roller 162 is provided at one end in the longitudinal direction of the mirror base 16, and a pressurizing spring 164 facing the roller 162 and having one end fixed to the mirror base 16, A rotatable roller 163 is provided that is pressurized in the direction of the roller 162. These two rollers 162 and 163 are configured to sandwich a guide rail 161 fixed to the main body of the copying machine with pressurization. The mirror base 16 also has a lens section 1, as explained in FIG.
8 is installed.

Regarding the operation of one embodiment of the present invention having the above configuration,
This will be explained below.

The movement of the lamp house 15, the movement of the movable mirror 14, and the rotation of the photosensitive drum 20 are linked, and in response to the rotation of the photosensitive drum 20 in the direction of arrow B, the lamp house 15 moves as shown in FIG. The movable mirror 14 moves from the left to the right direction (indicated by arrow C), and the movable mirror 14 moves from the top to the bottom (indicated by the arrow) in the figure. When the lamp house is at the position shown at 14, the lamp house is at the position shown at 15, and the document image located at 112 of the document surface 111 illuminated by the lamp house 15 is directed to the fixed mirror 13 along the first direction Dl. The light is then reflected by the fixed mirror 19 in the second direction D2. After being reflected again in the first direction Di by the moving mirror 14, it is guided to the photosensitive drum 20 via the lens section 18 and the fixed mirror 19.
A document image corresponding to 112 of document 11 is formed on photosensitive surface 21 .

As the photosensitive drum 20 rotates in the direction of arrow B, the lamp house 15 moves in the direction of arrow C, and the movable mirror 14 moves in the direction of arrow B. Therefore, the movable mirror 14a
When moved to the position shown in , the lamp house is at the position shown at 15a, and the lens section is moved to the position 18a.

At this time, a document image at a position corresponding to 113 of the document 11 is illuminated by the lamp house 15, and this illuminated document image 113 is guided to the fixed mirror 13 along the first direction Dla, and then guided to the fixed mirror 13 along the first direction Dla. It is reflected by D2a. Then, after being reflected in the first direction Dla by the movable mirror 14a, the
Since it is guided to the photosensitive drum 20, the original image 113 is formed on the photosensitive surface 21.

In the movement of the movable mirror 14 explained above, the lens part 18 and the movable mirror 14 move together (when the movable mirror is at the position shown at 14, the lens part is at the position shown at 18, and the lens part is at the position shown at 14a) When there is a movable mirror in the position, the lens part is in the position shown in 18a), and the first direction D1, [)la and the second direction D2, D2a are in a perpendicular relationship. Therefore, the first direction D1, Dla between the document surface 111 and the fixed mirror 13
The change in distance in is offset by the change in distance in the second direction D2 and D2a, and the distance from the document surface 112 to the lens section 18 and the distance from the document surface 113 to the lens section 18a are It remains constant regardless of the position of the mirror 14.14a, and the photosensitive surface 2 of the photosensitive drum 20
1, an image of the document surface 111 is always formed.

FIG. 3 is a schematic diagram showing the configuration of a second embodiment of the present invention.

In this embodiment, a movable mirror 14 is provided on a mirror base 16c, and an elongated rectangular mirror is provided at an angle of approximately 90 degrees with respect to the movable mirror 14 for scanning the light irradiating the document surface 111. Moving mirror 31 for lighting
is provided. And, even when the movable illumination mirror 31 moves, the upper part of the movable illumination mirror 31 is
The lamp house 1 irradiates the light beam in a direction parallel to the slide shaft 17 so that the optical axis of the light beam can be positioned approximately at the center of the illumination movable mirror 31.
5c, and a condensing lens 30 that condenses light from the lamp house 15c.

Note that the lamp house 15c and the condensing lens 30 are fixed to the main body of the copying machine, and even when the mirror base 16C moves, the lamp house 15C1 and the condensing lens 30 do not move. In other words, in the second embodiment,
A device that moves parallel to the document surface 111 is not provided, and the mirror base 16c, the two mirrors attached to the mirror base 16c, and the lens portion 18a are moved in a direction perpendicular to the document surface 111 (vertical direction). The structure is such that it can only be moved.

In the second embodiment as well, the method of forming the optical path (indicated by 1 and Kla on the dashed line) from the document surface 111 to the photosensitive surface 21 of the photosensitive drum 20 is the same as the embodiment shown in FIG. Since they are the same, the explanation thereof will be omitted, and the operation of illuminating the document surface 111 accompanying the scanning exposure of the document 11 will be explained.

When the mirror base is in the position shown in 16c, the light from the lamp house 15 passing through the condensing lens 30 and directed downward is reflected by the movable illumination mirror 31 in a direction substantially parallel to the document surface 111, and is fixed. Since the light is reflected upward by the mirror 13, the document surface 111 is irradiated from a substantially vertical direction.

The path of the light beam at this time is indicated by the two-dot chain line S1 in FIG. Since the intersecting angle θ of 31 is set to be slightly larger than 90 degrees, the optical path 1 for scanning exposure and the optical path S1 for illumination are located near the position shown at 112 on the document surface 111. The document surface 11 that intersects at , and requires illumination during scanning exposure
The position No. 2 is illuminated by light from the lamp house 15c.

The optical path in scanning exposure and the optical path of the illumination light beam intersect near the document surface 111 even when the mirror base 16c moves, so when the mirror base is at the position shown in 16d, The light beam from the lamp house 15c is reflected by the illumination movable mirror 31 and fixed mirror 13, respectively, and illuminates the document surface 113 to be exposed.

As shown in FIG. 2, the mirror base 16 in this embodiment can be guided at its center by the slide shaft 17 (guiding near the center of gravity), so the mirror base 16 is driven. The amount of vibration of the movable mirror 14 that occurs at this time is extremely small when compared with the vibration of a movable mirror having a mirror base whose both ends are guided by bearings.

In addition, it becomes possible to directly drive the vicinity of the center of gravity of the mirror base 16 (conventionally, by driving both ends, the center of gravity was driven as a resultant force), so the mirror base 16 can be driven. It is possible to prevent a decrease in efficiency.

Further, in the first embodiment, it is necessary to move the lamp house 15, but since the movement of the lamp house 15 is for illuminating the document surface 111 and not for imaging, Since precision is not required, the device is simplified.

Furthermore, in the second embodiment, there is no need to move the lamp house 15C, so the driving device is simple.

Note that the present invention is not limited to the above-mentioned embodiments, and in the first and second embodiments, the movement of the mirror base 16 has been explained using a drive wire 165, but other driving methods, such as It is possible to adopt a configuration in which the drive is performed by a linear motor or the like.

Furthermore, although the configuration has been described in which scanning exposure of the document surface 111 is performed by moving the movable mirror 14 downward, scanning exposure of the document surface 111 is performed by moving the movable mirror 14 upward from below. It is possible to have a configuration in which this is done.

In addition, the lamp house 15c and the lens portion 3 shown in FIG.
0 to the mirror base 16c, and
By moving the mirror base 16c together with the mirror base 16c, it is possible to create a configuration in which the distance from the lamp house 15c to the document surface 111 remains unchanged even when the mirror base 16c moves.

<Effects of the Invention> The optical device of the copying machine according to the present invention has a first direction that is perpendicular to and downward to the document placement surface, and a second direction that is parallel to the document placement surface. , with a fixed mirror,
The structure is such that the light from the document traveling in the first direction is reflected in the second direction, and the light from the fixed mirror is reflected in the first direction by the movable mirror. The direction of the reaction force is vertical, and in the vertical direction it is less likely to vibrate due to the action of gravity, which has the effect of reducing the vibration of the copying machine when copying at high speed. play.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the configuration of the first embodiment of the present invention, FIG. 2 is a plan view showing the detailed configuration of the mirror base, and FIG. 3 is a diagram showing the configuration of the second embodiment of the present invention. FIG. 4 is a schematic diagram showing the configuration of an optical device of a conventional copying machine. 11... Original 13... Fixed mirror 14... Moving mirror 18... Lens unit 20... Photosensitive drum 21... Photosensitive surface 111... Original surface 121... Original placing surface Di ...First direction D2...Second direction. Patent applicant Sharp Corporation

Claims (1)

[Claims] (1) When the first direction is perpendicular to the document placement surface of the document table and directed downward from the document table, and the second direction is parallel to the document placement surface. , a fixed mirror that reflects light from the document traveling in a first direction in a second direction;
A movable mirror is provided on an optical path connecting the document surface and the photosensitive surface of the photosensitive drum. an optical device for a copying machine, comprising: a lens section for scanning a document surface by moving the movable mirror in a direction perpendicular to the document placement surface;