JPH0345123Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Technical Field> The present invention relates to a position detection device for detecting the position of a moving object.

<Prior Art> Copying machines generally optically scan a document placed on a document table in order to project the image of the document onto a moving (or rotating) photoreceptor. For example, as an optical scanning means, there is a method in which a document table is moved relative to an optical system for image projection, or a document table is fixed and a part of the optical system is moved. In addition, when variable-magnification copying is performed separately from these moving systems, some systems move the projection lens in the optical axis direction according to the magnification.

Each of the moving systems described above is driven and controlled in response to a signal that detects when each moving object reaches a specified position. For example, when the original table or optical system is scanning, a signal that detects the end position of the scan is used to stop the scanning of the document table or the optical system and return it to the starting position. When the document placing table or the optical system returns to the starting position, this is detected and the document placing table or the like is stopped at that position. Further, the drive of the projection lens is similarly controlled.

Here, in order to detect the position of each of the moving objects mentioned above, micro switches with large strokes are provided corresponding to the start position and the scan end position in order to ensure reliable detection. However, microswitches are expensive and large, so they are not suitable for space saving. Therefore, as a space-saving and inexpensive detection means,
It is conceivable to use a tact switch that is widely used in electronic desktop calculators and the like. Since this tact switch has a very small stroke, the operation becomes very unstable due to variations in the mounting position for position detection and variations in the position of the operating part, making accurate position detection impossible. Furthermore, a tact switch is a type of switch that is pressed from above, so when it is operated by an object moving from the side, not only will it malfunction, but the switch itself will be damaged due to the force applied to the actuating part from the side. This can easily lead to malfunctions.

<Purpose of the invention> The object of the invention is to provide a device that can reliably detect the position of a moving object using a tact switch.

<Embodiment> FIG. 1 is a perspective view showing an example of a moving body according to the present invention, and shows a moving mechanism for a projection lens of a copying machine. Although the figure shows a moving mechanism for a moving body of a lens holder, this is just an example, and the present invention is not limited to this, and can of course be applied to all types of position detection of a moving body. In the figure, reference numeral 1 is a projection lens that projects an image of an original onto a photoreceptor (not shown). A lens 1 is held by a lens holder 2. This lens holder 2 is provided so as to be movable (slide) with respect to a slide shaft 4 held by a frame 3. Further, a lead shaft 5 for moving the lens holder 2 is rotatably provided on the frame 3 parallel to the slide shaft 4. A threaded portion 6 threaded onto the lead shaft 5 is fixed to the lens holder 2.

At one end of the lead shaft 5 protruding from the frame 3, there is a
A gear 7 is fixed, and the gear 7 meshes with a gear 9 directly connected to the shaft of a motor 8. Therefore, when the lead shaft 5 rotates due to the rotation of the motor 8, the lens holder 2 is moved along the direction of the slide shaft 4 via the threaded portion 6.

The lens holder 2 has an actuating member 10 formed of a plate spring for detecting the position of the lens 1.
is provided. As shown in FIG. 2, a plurality of tact switches 11 for position detection are arranged in the direction of movement of the lens 1, corresponding to the tip of the actuating member 10. Tact switch 11
is attached to a wired switch board 12, with the operating portion 11a protruding from a hole 14 provided in the guide plate 13. The guide plates 13 are arranged in parallel along the moving direction of the lens holder 2, and the holes 14 are aligned in response to the position detection of the lens 1.
is drilled. The amount of protrusion of the operating portion 11a of the tact switch 11 is at least
1 is pressed by the actuating member 10 to turn on (operate). Board 12 with switch 11 attached
is mounted on the guide plate 13 so that the operating portion 11a protrudes from the plane of the guide plate 13 by the amount of protrusion described above.

Further, the tact switch 11 of the operating member 10
A roller 15 is rotatably provided at the tip portion corresponding to the operating portion 11a. In order to protect the tact switch 11, a sheet 16 of about 0.1 to 0.3 mm is provided to cover the hole 14.

According to the structure described above, the motor 8 rotates and the lens holder 2 is moved in the direction of the slide shaft 4 to a designated position, so that the rollers 15 of the actuating member 10 move at the tact time of the above position. Press the operating portion 11a of the switch 11. The rotation of the motor 8 is stopped by the ON signal of this tact switch 11. At this time, when the lens holder 2 moves, the rollers 15 of the actuating member 10 made of a leaf spring come into contact with the guide plate 13 via the seat 16 and are moved, thereby stabilizing the detection operation of the tact switch 11. . In particular, although the lens holder 2 is moved laterally, the operating portion 11a of the tactile switch 11 can be reliably pressed by the operating member 10 due to the action of the leaf spring or the like. Furthermore, by providing the sheet 16, it is possible to prevent the actuating member 10 from getting caught in the actuating portion 11a, thereby protecting the switch 11 itself and ensuring smooth movement of the lens holder 2.

Here, by changing the thickness of the sheet 16, it is possible to change the timing of the operation of the tact switch 11. For example, by making the sheet 16 thicker, the ON (operation) range can be expanded.

According to the present invention, an example is shown in which a roll-shaped roller 15 is attached to the actuating member 10, but the present invention is not limited to this, and the same effect can be expected even if a block-shaped roller is provided rotatably. Further, the tip of the actuating member 10 may be brought into direct pressure contact with the guide plate 13 or the like without providing the rollers 15 or the like.

Furthermore, the width B of the rollers 15 of the actuating member 10 is
As shown in the figure, the opening width A of the hole 14 of the guide plate 13 for arranging the tactile switch 11 is set so that A<B. This is Koro 15
At the same time, the actuating portion 11a of the tact switch 11 is prevented from being pressed any further to protect the tact switch 11, and at the same time, it prevents excessive force from acting on the board 12 and prevents the board 12 from being backed up. I need it.

<Effect of the invention> According to the position detection device of the invention, the operating part of the tact switch is made to protrude from the guide plate, and the operating member is placed on the movable body corresponding to the tact switch so as to press against the guide plate. Because of this provision, the actuating member can reliably press the operating part of the tact switch, and the position of the moving body can be detected reliably. Since the position can be detected using a tact switch in this way, the position detection device itself can be downsized and manufactured at a very low cost.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a lens moving mechanism of a copying machine, which is an example of a movable body according to the present invention, FIG. 2 is a sectional view showing a position detection device of the present invention, and FIG. 3 is a sectional view showing details of the detection unit. It is a diagram. 1...lens, 2...lens holder, 4...
Slide shaft, 8...motor, 10...operating member,
11... Tact switch, 11a... Operating part, 1
3... Guide plate, 14... Hole, 15... Roll, 1
6...Sheet.

Claims (1)

[Scope of utility model registration request] A device for detecting the position of a moving object moving in order to control the position of the moving object, comprising: a guide plate arranged in parallel in the moving direction of the moving object; and a guide plate corresponding to a detected position of the moving object. a tact switch having a hole provided in the hole; a tact switch having an operating part disposed in the hole and protruding from the plane of the guide plate; What is claimed is: 1. A position detection device for a moving body, comprising: an actuating member;