JPH0439643A - Detection of home position for zoom variable power optical system - Google Patents

Abstract

PURPOSE:To rapidly, surely and accurately restore and position a photographing lens and an optical path length variable means to/on a home position by positioning the lens and variable means on the home position for equal power and then moving them to a focus magnification position. CONSTITUTION:A sensor 16 fixed on a position corresponding to a home position '0' is formed so as to be continuously OFF when an actuator 15 fixed to the projection lens 6 is positioned on the enlarging magnification side L and to be continuously ON when the actuator 15 is positioned on the reducing magnification side S. For instance, the actuator 15 positioned on the side L at the time of turning on a power supply is moved to the home position '0', after passing the sensor 16 once, moved in the reverse direction, and reaches and stops on the prescribed position P, so that the actuator 15 is positioned on the home position '0'. The optical path length variable means also is positioned following the lens 6. Thus, the projection lens and the optical path length variable means can be rapidly and accurately restored and positioned to/on the home position at the time of turning on the power supply.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for moving the projection lens and optical path length variable means of a scanning zoom magnification variable optical system such as a copying machine to the home button/a at the same magnification position when the power is turned on. This invention relates to a detection method for returning and positioning.

[Conventional technology]

In a scanning type zoom variable magnification optical system of a copying machine, etc., a light source 2, a plurality of mirrors 3, 4, 5, 7, and a projection lens 6 are used to expose the document to the document table glass l as shown in FIG. An image is formed by forming an image of the original screen 14 on the original table glass 1 on an image carrier such as a photosensitive drum 10. The light source 2 and the first mirror 3 are integrated to form a first traveling base, and the second mirror 4 and the third mirror 5 are integrated to form a second
A traveling platform is formed and runs in the same direction parallel to the document table glass 1 to scan the document screen 14.

To change the image magnification of such a scanning zoom variable magnification optical system, focus adjustment is performed by adjusting the position of the projection lens 6 in the direction of the arrow in accordance with the set magnification, and at the same time, the projection lens 6 is adjusted in the direction of the arrow. 2. The mirror position is moved by either a front pass method in which the third mirror 4.5 is moved or a back pass method in which the fourth mirror 7, which is the final mirror, is moved. I am trying to change the optical path length.

Such changes in image magnification are normally performed on the original screen 14.
and the image formed on the surface of the photoreceptor 10 are set at a same magnification position where 1=1, and the projection lens 6 and the mirror are moved toward the enlargement magnification side or the reduction magnification side from the home position as a base point. A desired image magnification can be obtained by moving and adjusting the position of the optical path length variable means.

This home position, that is, the same-size position, is determined by the same-size position sensor 1 provided corresponding to the same-size position as shown in the figure.
6 and, for example, an overrun sensor 16a provided beyond the minimum magnification position and an actuator 15 provided on the base 6a of the projection lens 6.

That is, when the projection lens 6 and the optical path length variable means such as a mirror are located, for example, on the reduction magnification side, their respective positions are confirmed when the power is turned on; After the actuator 15 crosses the sensor 16a and confirms its position, it moves in the opposite direction again, and is detected and stopped at the position where it crosses the same-magnification position sensor 16. Conversely, even when the projection lens 6 and the optical path length variable means such as a mirror are located on the magnification side, they move toward the same magnification position, pass across the sensor 16a, and then turn around. It moves and crosses the sensor 16 again, that is, it moves from the reduction magnification side and is detected at the same position as when it crosses the sensor 16 and stops, and the home position, which is the same magnification position, is positioned. There is.

Furthermore, related to the prior art, Utility Model Application No. 56-80544 and Japanese Patent Application Publication No. 54703 are known. The former Japanese Utility Model Application No. 56-80544 relates to a correction means for detecting and correcting the deviation between the initial position and the actually returned position when the scanning optical device is returned to the initial position. The latter, Japanese Patent Publication No. 1-54703, uses a variable-magnification image forming apparatus that converts the image magnification to form an image and then automatically sets the image to the same magnification position or the image magnification position frequently used by the user. Both systems use multiple sensors for this purpose.

[Problem to be solved by the invention]

As described above, conventionally, two sensors installed at two locations are used to determine the same magnification position, that is, the home position, of the projection lens and the variable optical path length means. Therefore, a large amount of cost and man-hours are required for a plurality of expensive sensors, associated east lines, assembly and adjustment, etc. In addition, as in the above example, in order to confirm the position of the projection lens on the reduction magnification side and the optical path length variable means when the power is turned on,
For example, on the minimum magnification side, it is moved each time to a position exceeding the minimum magnification position and overruns, and then returned to the same magnification position and positioned, so this movement requires time. The present invention solves these problems and quickly and accurately adjusts the projection lens and the optical path length variable means by using one sensor or actuator provided at the same magnification position, that is, the home position, and the actuator or sensor provided on the movable body. The object of the present invention is to provide a method for detecting a home position by which the user can return to the home position and perform positioning.

[Means to solve the problem]

This purpose is to provide a scanning zoom magnification optical system that forms an image at each magnification by moving a projection lens and an optical path length variable means on the original screen. A sensor or actuator for detecting the home position is fixedly provided on the main body frame, an actuator or sensor for activating the sensor or actuator is provided on the projection lens or the optical path length variable means, and the actuator or sensor is located at a position corresponding to the home position. At a position on the magnification side of one of the fixedly disposed sensors or actuators, the sensor continues to operate in either ON or OFF,
At the position on the reduction magnification side, the actuator or sensor is formed to remain OFF or ON in the opposite direction to the enlargement magnification side, and when the power is turned on, the actuator or sensor located on the expansion side or reduction side moves to the home position side in the opposite direction, and The position across the sensor or actuator is detected and the projection lens and the optical path length variable means are positioned at the home position at the same magnification! This is achieved by a method for detecting the home position of a zoom optical system at equal magnification, which is characterized in that the projection lens and the optical path length variable means are moved to a predetermined magnification position in a double manner.

〔Example〕

One embodiment of the present invention is shown in FIG.
The top view of the same figure, the figure showing the procedure of the detection means when the projection lens returns to the home position from the reduction magnification side of FIGS. 3(a) and 3(b), and FIGS. 4(a) and 4(b), (
The procedure will be explained with reference to c), which shows the same procedure when the projection lens is located on the magnification side.

However, the present invention is not limited to this embodiment.

In addition, members having the same functions as in the past are represented using the same symbols.

As shown in FIGS. 1 and 2, the scanning zoom variable magnification optical system includes a light source 2 that illuminates the document screen 14 on the document table glass l.
and the first mirror 3 that projects and reflects the screen 14 are integrally formed.
The mirror 5 is integrally formed with the second traveling base 4a, the projection lens 6, and the fourth mirror 7 and the fifth mirror 8, which receive and reflect the image from the projection lens 6, are integrally formed.
; It is constituted by an optical path length variable means 7a, a fixed sixth mirror 9 which forms an image of the reflected light from the optical path length variable means 7a on the surface of a photoreceptor 10, and the photoreceptor 1O which is an image carrier. A slide bearing 12 provided at one end of the first traveling base 3a and a slide bearing 13 provided at both ends of a frame integral with the second traveling base 4a are attached to both ends of the zoom magnification optical system device 20. The guide bars 11 are respectively fitted in parallel with the glass 1 and supported, and the other end of each carriage is supported on the guide rail lla of the device 20 via rollers. The document screen 14 is then run parallel to the document table glass l and in the same direction along the guide bar 11 and the guide rail lla.
I'm trying to scan it.

To convert the image magnification of the zoom magnification optical system configured as described above, focus adjustment is performed by moving the projection lens 6 in the direction indicated by the arrow on the optical axis in accordance with the set magnification, and an optical path length variable means is used. The fourth mirror 7 and the fifth mirror 8 are
At the same time, by moving and adjusting the position in the direction indicated by the arrow on the optical axis, the total optical path length from the original screen 14 to the photoreceptor 10 can be changed to obtain a desired image magnification.

Then, the normal image magnification is converted to the enlargement magnification side or the reduction magnification side using the same size image position as the base point, as described above. The present invention is a detection method that eliminates the above-mentioned drawbacks, detects the same magnification position, that is, the home position, with an extremely simple structure, and positions the projection lens 6 and the optical path length variable means. That is, the home position detecting means is a zoom magnification optical device 20 as shown in the figure.
It is composed of a transmissive type 7-photo sensor 16 fixedly disposed at a position corresponding to the home position, and a plate-shaped actuator 15 provided integrally with the base 6a of the projection lens 6. 15 is the sensor 16
The home position is detected when the camera crosses the . For example, when the actuator 15 is located on the reduction magnification side S as shown in FIG.
When the power is turned on, the actuator 1 immediately moves in the direction of the home position 0 shown on the vertical axis as shown in FIG. 3(b).
5 crosses the sensor 16 and detects the CPU17.
When a predetermined position P is reached, the actuator 15, that is, the projection lens 6 stops, and is positioned at home position 0.

Further, as shown in FIG. 4(a), the actuator 15
When is on the enlarged magnification side, the sensor 16 is OFF.
When the power is turned on, it moves in the direction of the home position 0 shown by the arrow, and after passing through the sensor 16 and moving to the position shown in FIG. 4(b), it moves again to the position shown by the arrow. It moves in the opposite direction and is detected by moving across the sensor 16 as shown in FIG. When the point P is reached, the actuator 15, that is, the projection lens 6 stops and is positioned at the home position 0 in the same manner as described above. Incidentally, the optical path length variable means (not shown) located on each of the magnification sides S and L are also positioned to follow the projection lens 6 to the home position, that is, the optical path length of the same image magnification. .

As shown in FIG. 1, the ON and OFF configurations of the actuator 15 and the sensor 16, the sequence of the movement direction slip detection procedure when the power is turned on, etc. are all stored in advance in the CPU 17 and controlled by the CPU 17. The projection lens 6 is moved by driving the first stepping motor 18, and the optical path length variable means is also moved by the second stepping motor 19, which is similarly driven, to return to the home position. There is. In addition, contrary to the above-mentioned example, when the actuator 15 is on the reduction magnification side S, the sensor 16 is turned off, and when it is on the enlargement magnification side, the actuator 15 is rearranged so that it continues ONL. There is no problem in moving the . Then, when the power is turned on, the one sensor 16 and the actuator 15 configured as described above cause the projection lens 6 and the optical path length variable means to change to Tif.
It is possible to quickly and accurately return to the home position 0 even at any position away from the home position 0. Further, in the above-mentioned example, since the detection method is such that the actuator 15 is always moved from one direction, it is possible to eliminate the adverse effects caused by mechanical backrun when the projection lens 6 and the optical path length variable means are moved. This is very convenient in terms of accuracy.

When the user specifies a desired image magnification, the projection lens 6 and the optical path length variable means, which are positioned at the home position 0, are activated by the first stenting motor 18 again by the application of pulses controlled by the CPU 17. The projection lens 6 is moved and adjusted by driving, and at the same time, the optical path length variable means is also moved by the second stepping motor 19 and positioned so as to obtain a designated image magnification.

The original screen 14 illuminated by the light source 2 facing the original platen glass l runs along the guide bar 11 and the guide rail lla on the first traveling table 3a integrated with the first slider 12. is the original platen glass 1
The second traveling table 4 runs parallel to the optical axis direction and in the optical axis direction.
The guide bar 1 has a common slide bearing 13 integrated with a.
1 and the guide rail lla in the same direction to be scanned.

Then, the projected image from the third mirror 5 passes through the projection lens 6, the fourth mirror 7, and the fifth mirror 8, and enters a fixed sixth mirror 9 at the final stage, where it is reflected and exposed to the light. A projected image with a required magnification is formed on the body 10 surface.

Although the above-mentioned optical path length variable means uses a rear pass method to change the optical path length during image magnification conversion, there is no problem in using an optical path length variable means using a front pass method as in the conventional example described above.

Alternatively, the actuator 15 may be provided at a fixed position and the sensor 16 may be provided on a movable body.

〔Effect of the invention〕

The very simple method of detecting the Baum position of a zoom magnification optical system according to the present invention not only reduces the cost of the device, but also allows the projection lens and the optical path length variable means to quickly and accurately return to their home positions and position them when the power is turned on. Now, each magnification conversion operation based on it also works quickly and accurately.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing the configuration of a zoom variable magnification optical system and home position detection means according to an embodiment of the present invention, FIG. 2 is a top view of the same, and FIGS. 3(a) and (b) are Embodiment 1 of the present invention is a diagram showing the process of returning to the home position when the projection lens is on the reduction magnification side, and FIGS. A diagram showing the process of returning to the home position when the zoom lens is on the magnification side, and FIG. 5 is a side view showing an outline of a conventional zoom variable magnification optical system and home positive/con detection means. l...Original table glass 2...Light source 3...Sl mirror 4...Second mirror 5...Third mirror
6... Projection lens 7... Fourth mirror 8...
・Fifth mirror 9...Sixth mirror IO...Photoreceptor 11...Guide bar 14...Original screen 15
...actuator 16...sensor 16a...
Overrun sensor 17... CPLl 18... First stepping motor 19... Second stepping motor 20... Zoom variable magnification optical device

Claims (1)

[Claims] In a scanning zoom variable magnification optical system that forms an image at each magnification by moving a projection lens and an optical path length variable means on a document screen, detecting home positions of the projection lens and the optical path length variable means at the same magnification. A sensor or actuator is fixedly provided on the main body frame, an actuator or sensor for actuating the sensor or actuator is provided on the projection lens or the optical path length variable means, and the actuator or sensor is fixedly disposed at a position corresponding to the home position. At a position on the magnification side for one sensor or actuator installed, the sensor is O
The actuator or sensor is formed so that it continues to operate in either N or OFF, and continues to be OFF or ON in the position on the reduction magnification side, opposite to the enlargement magnification side, and is located on the expansion side or the reduction side when the power is turned on. Each moves to the home position side in the opposite direction, detects the position where it crosses the sensor or actuator, positions the projection lens and the optical path length variable means at the home position at the same magnification, and then moves to a predetermined magnification position. A method for detecting a home position of a zoom variable magnification optical system at equal magnification, characterized by moving a projection lens and an optical path length variable means.