JPS60213936A - Magnification modifying device of electrophotographic copier - Google Patents

Abstract

PURPOSE:To prevent the titled device from going to large in size by moving a mirror for directing light reflected by an original through a lens to a photosensitive body and changing also the fitting angle of the mirror. CONSTITUTION:At a time of equal magnification copying, i.e. before the movement of the 4th mirror 20, the light reflected by the original which is advanced in the arrow E direction is turned vertically to the surface of the photosensitive drum 9 in the arrow F direction by the 4th mirror. At a time of expanding or contracting popying, the 4th mirror 20 is moved and the incident angle of the light reflected by the original to the 4th mirror 20 can be also changed, so that the light reflected by the original advancing in the arrow E direction independently of the position of the mirror 20 can be turned vertically to the surface of the drum 9 in the arrow G direction. The sliding surface 24c of a cam 24 is determined on the basis of conditions such as the moving direction of a mirror shaft 22, the moving distance of the mirror shaft 22 and the focal distance of the lens 8 so that the light reflected by the original is turned always at a fixed angle to the surface of the drum 9 even if the 4th mirror 20 is moved to change the optical path of the reflected light.

Description

Detailed Description of the Invention (Field of Application) The present invention relates to a variable magnification device for an electrophotographic copying machine, and particularly to a variable magnification device for an electrophotographic copying machine that does not increase the size of the electrophotographic copying machine. It is related to.

(Prior Art) A conventional variable magnification device for an electrophotographic copying machine will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing an example of an optical device of an electrophotographic copying machine.

In the figure, below the platen glass 5 are a first mirror 1, a second mirror 2, a third mirror 3, a lens 8, a fourth mirror 4, and a photosensitive drum 9, each in a predetermined positional relationship. It is located.

An illumination lamp 6 and a reflector 7 are attached to the first mirror 1 integrally with the first mirror 1.

The first mirror 1, the illumination lamp 6 and the reflector 7 can be moved parallel to the platen glass 5 - ie in the direction of arrow B.

The first mirror 1, illumination lamp 6 and reflector 7 are moved until they reach the positions IA, 6A and 7A, for example. The second mirror 2 and the third mirror 3 can move in the direction of arrow B at half the speed of movement of the first mirror 1.

The document placed on the platen glass 5 is illuminated by the light emitted from the illumination lamp 6, and the reflected light is transmitted to the first
reflected by the second and third mirrors 1, 2°3,
passing through the lens 8 in the direction of arrow E, and then passing through the fourth lens 8 in the direction of arrow E.
is reflected in the direction of arrow F by the mirror 4 of the photosensitive drum 9.
projected on top.

The fourth mirror 4 always directs the reflected light of the original at a constant angle (usually perpendicular) to the photosensitive drum 9 so that the original image projected onto the photosensitive drum 9 is not distorted. It is located within the electrophotographic copying machine.

In the electrophotographic copying machine having the above configuration, in order to enlarge or reduce the original image formed on the recording paper, as long as the focal length of the lens 8 is constant, the lens 8 must be used to direct the reflected light from the original. Optical path: In other words, the optical path length from the document surface to the photosensitive drum 9 must be increased at the same time as moving along the optical axis of the imaging lens system.

Generally, the platen glass 5 and the photosensitive drum 9 are fixed to the main body frame of the electrophotographic copying machine, so the optical path length must be changed by moving the mirror.

That is, in the electrophotographic copying machine shown in FIG.
It is moved and placed in the position shown in A and 3A.

Although not shown in the figure, the lens 8 is also moved. Then, after that, the first mirror 1, the illumination lamp 6 and the reflector 7, and the second mirror 2 and the third
The mirror 3 is scanned in the direction of arrow B, and copying is performed.

In the electrophotographic copying machine shown in FIG. 1, as described above, when obtaining an enlarged copy or a reduced copy, the second mirror 2 and the third mirror 3 are , it must not be placed so as to protrude outside of the platen glass 5.

Therefore, the second mirror 2 and the third mirror 3
However, the width of the electrophotographic copying machine becomes larger by the distance ll1llD to move to positions 2A and 3A.

Next, FIG. 2 shows another example of an electrophotographic copying machine having copy enlargement and reduction functions.

Figure 2 shows another example of the optical device of an electrophotographic copying machine.
It is a schematic diagram.

In the figure, the same reference numerals as in FIG. 1 represent the same or equivalent parts.

In FIG. 2, the reflected light from the original that has passed through the lens 8 in the direction of the arrow E is directed in the direction of the arrow F by the fourth mirror 4, the fifth mirror 10, and the sixth mirror 11, and is directed onto the photosensitive drum 9. The optical device is configured to project J: uni.

In the electrophotographic copying machine having the above configuration, when enlarging or reducing a copy image, the lens 8 is moved and the fourth mirror 4 and the fifth mirror 10 are replaced with the first mirror 1, second mirror 2, and third
- in the scanning direction (direction of arrow B) of mirror 3 etc.
For example, move and place it in the positions shown in 4A and 10A.

In the configuration shown in FIG. 2, the fourth mirror 4 and the fifth mirror 10 at the same magnification are placed near the center of the electrophotographic copying machine, so that the Fourth mirror 4 and fifth mirror 10
Even if the electrophotographic copying machine is moved, the width of the electrophotographic copying machine will not increase.

However, compared to the case of FIG.
The height of the electrophotographic copying machine increases by the distance H between the mirror 10 and the mirror 10.

Furthermore, since there are a large number of mirrors, the structure becomes complicated and the manufacturing cost increases.

As described above with reference to FIGS. 1 and 2, conventionally, when an electrophotographic copying machine is configured to have an enlargement copying and/or reduction copying function, the electrophotographic copying machine becomes larger, Furthermore, there is a drawback that the production cost increases excessively.

(Objective) The present invention has been made to eliminate the above-mentioned drawbacks, and its object is to make it possible to obtain enlarged copies and/or reduced copies without increasing the size of the electrophotographic copying machine. An object of the present invention is to provide a variable magnification device for an electrophotographic copying machine.

(Summary) The present invention provides that if the fourth mirror 4 in FIG.
Based on the idea that it is possible to make it unnecessary, we have developed this technical idea.

In order to achieve the above object, the present invention includes a mirror moving means for moving a mirror for directing the original reflected light that has passed through a lens onto a photoreceptor so as to increase the optical path length of the original reflected light. , a magnification change device of an electrophotographic copying machine is configured by a cam mechanism that changes the inclination angle of the mirror so that the reflected light of the original directed toward the front δ photoreceptor is always incident at a predetermined angle. It is distinctive in that it did so.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 3 is a schematic diagram of an optical device of an electrophotographic copying machine to which an embodiment of the present invention is applied, and FIG. 4 is a detailed diagram of the main part of the present invention in FIG. 3.

In the figures, the same reference numerals as in FIGS. 1 and 2 refer to the same or equivalent parts.

First, in FIG. 3, the reflected light from the document that has passed through the lens 8 in the direction of arrow E is directed by the fourth mirror 20 in the direction of arrow F, and is projected onto the photosensitive drum 9.

The fourth mirror 20, as shown in detail in FIG.
For example, its side surface is fixed to the mirror holder 21.

Further, at a predetermined position of the mirror holder 21, 1. X horizontally,
A mirror shaft 22 is fixed, and further, the mirror shaft 22 is rotatably supported by means not shown in the drawings with respect to the electrophotographic copying machine.

The fourth mirror 20 only needs to be rotatable about an axis perpendicular to a plane containing the incident light on the fourth mirror 20 and the reflected light from the fourth mirror 20, so the mirror shaft 22 may be fixed, and the mirror holder 21 may be rotatably provided with respect to the mirror shaft 22.

A cam follower 23 is further fixed to the lower part of the mirror holder 21.

A cam 24 disposed below the mirror boulder 21 and fixed inside the electrophotographic copying machine has a sliding movement 2.
4G is formed into a shape as described below.

That is, the sliding surface 24G is the fourth mirror 20
It is shaped to have a predetermined inclination with respect to the reflected light of the original incident in the direction of arrow E.

In other words, the sliding movement 24G is shaped so as not to be parallel to the reflected light of the document traveling in the direction of the arrow E.

The mirror boulder 21 is biased in the direction of the arrow so that the cam follower 23 is always in contact with the sliding surface 24C.

Further, the means for rotatably supporting the mirror shaft 22 can move in parallel to the reflected light of the original incident on the fourth mirror 20 in the direction of arrow E.

Now, in one embodiment of the present invention having the above configuration,
When obtaining enlarged or reduced copies, use lens 8.
At the same time, the means for rotatably supporting the mirror shaft 22 is moved in parallel to the document reflected light incident on the fourth mirror 20 in the direction of arrow E. Since the means for changing the position of the lens 8 is known,
The explanation will be omitted.

As the means for rotatably supporting the mirror shaft 22 moves, the mirror holder 21 also moves in the direction of the arrow. Here, as mentioned above, since the mirror boulder 21 is biased in the direction of the arrow (counterclockwise in FIG. 4), the cam follower 23 is pushed against the sliding surface 24G.
The object will follow the object and move while sliding.

Therefore, the mirror holder 21 is moved in the direction of the arrow and gradually rotated in the direction of the arrow J (clockwise).

Therefore, in order to obtain a copy having a predetermined enlargement or reduction ratio, the mirror shaft 22 is connected to the mirror shaft 22A.
If the fourth mirror 20 is moved to the position
．． The mirror holder 21 and the cam follower 23 are also 2 each.
Move to positions OA, 21A, J3 and 23A.

Furthermore, the angle of incidence of the document reflected light incident on the fourth mirror 20 changes before and after the mirror shaft 22 moves.

Now, in a general electrophotographic copying machine, the reflected light of the original is irradiated perpendicularly to the surface of the photoreceptor so that the original image projected onto the photoreceptor is not distorted as described above. shall be configured to

In FIG. 3, during equalization copying - that is, before the fourth mirror 20 is moved at 110, the reflected light of the original traveling in the direction of arrow E is reflected by the fourth mirror 20.
It is directed perpendicularly to the surface of the photosensitive drum 9 (in the direction of arrow F).

During enlargement or reduction copying, as described above, as the fourth mirror moves, the incident angle of the light reflected from the original can be changed. The traveling reflected light of the original can be directed perpendicularly to the surface of the photosensitive drum 9 (in the direction of arrow G).

Even if the fourth mirror 20 moves to change the optical path length of the reflected light from the original, it is in contact with the cam follower 23 so that the reflected light from the original can always be directed at a constant angle with respect to the surface of the photosensitive drum 9. The shape of the sliding surface 24C of the cam 24 corresponds to the traveling direction of the document reflected light incident on the fourth mirror 20,
It is determined by taking into consideration conditions such as the moving direction of the mirror shaft 22, the moving distance of the mirror shaft 22, and the focal length of the lens 8.

Therefore, although the sliding movement 24C is depicted as a flat surface in FIG. 4, it may be formed on a curved surface depending on the settings of the aforementioned conditions.

In one embodiment of the present invention as described above, when enlarging or reducing copying, the mirror shaft 22 is
Although it has been described that the mirror moves parallel to the reflected light of the original incident on the fourth mirror 20, it is not limited to this, and may move in any direction depending on the shape of the sliding movement 24C. .

In other words, the moving direction of the mirror shaft 22 and the surface shape of the sliding surface 24C that comes into contact with the cam follower 23 are correlated with each other.

In addition, in a general electrophotographic copying machine, the fourth mirror 20 is arranged relatively inside the electrophotographic copying machine, so even if the fourth mirror is moved, the electrophotographic copying machine There is no risk of the device becoming larger.

Also, the sliding surface 2 of the cam 24 that contacts the cam follower 23
4. The electrophotographic copying machine can also be configured so that a copy can be enlarged and/or reduced steplessly by forming C so that it changes continuously.

(Effects) As is clear from the above description, according to the present invention, the following effects are achieved. That is, by moving the mirror for directing the reflected light of the document toward the photoreceptor after passing through the lens. At the same time, the mirror's mounting angle is changed, so (1) the electrophotographic copying machine does not need to be enlarged, and (2) the manufacturing cost can be reduced.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of an optical device of a conventional electrophotographic copying machine, FIG. 2 is a schematic diagram showing another example of an optical device of a conventional electrophotographic copying machine, and FIG. A schematic diagram of an optical device of an electrophotographic copying machine to which one embodiment is applied, FIG.
FIG. 3 is a detailed view showing the main part of the present invention in the figure. 1...first mirror, 2...second mirror, 3...
- Third mirror, 5... Platen glass, 6... Illumination lamp, 7... Reflector, 8... Lens, 9...
... Photoreceptor, 20... Fourth mirror, 21... Mirano 1 (Ruri), 22... Mirror shaft, 23...
・Kamfu 10A, 24...Cam, 24G...Representative Patent Attorney Michito Hiraki and 1 other person Figure 1 O 2 Figure

Claims (1)

[Claims] (1) It has a mirror for making the reflected light of the original incident on the lens, and a mirror for directing the light emitted from the lens onto the photoreceptor, and the reflected light of the original is focused on the photoreceptor by the lens. In the variable magnification device for an electrophotographic copying machine configured as above, a lens moving means for moving the lens on its front axis and a mirror for directing the light emitted from the lens onto the photoreceptor are moved. and a cam mechanism that changes the angle of the mirror with respect to the optical axis so as to maintain the required angle of light directed toward the photoreceptor at a predetermined value. Features a variable magnification device for electrophotographic copying machines. (2) The cam mechanism has an axis perpendicular to a plane containing incident light to the mirror and reflected light from the mirror, such as a mirror holder that holds a mirror for directing the light emitted from the lens onto the photoreceptor. , a means for rotatably holding the mirror holder, a cam follower provided on the mirror holder, and a sliding surface arranged perpendicularly to the plane so as to face the cam follower. An electrophotographic copying device as set forth in Patent No. 1, characterized in that the electrophotographic copying device is equipped with a sliding cam and means for biasing the mirror holder around the shaft so that the cam follower and the sliding surface come into contact with each other. The machine's variable magnification device.