JPS6328293B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for manually releasing a movable original table in an electrophotographic copying machine from a state where its movement is locked at the starting position.

This type of method charges the circumferential surface of a photoreceptor drum, forms an electrostatic latent image corresponding to the document through an exposure optical system, develops this electrostatic latent image with a developer, and transfers it to paper. It is known that this is one of the copying processes in an electrophotographic copying machine.

Now, the above-mentioned exposure optical system may be of a fixed type, in which the original table on which the original is placed is fixed, and the optical system consisting of a light source lamp, a plurality of reflecting mirrors, an imaging lens, etc. is moved; There is also a movable document platform type in which the optical system is fixed and the document platform moves back and forth.

Now, with reference to FIG. 1, a reciprocating mechanism of the movable document table in the exposure optical system with respect to the document table will be briefly explained.

Reference numeral 24 in the figure indicates a document mounting table mounted on the upper surface of the copying machine main body so as to be slidable in the horizontal direction. The document mounting table 24 is mainly composed of a transparent plate 22 and a document pressure plate 23 that can be opened and closed.

On one side edge of the document mounting table 24 parallel to its moving direction, there is a long and thin member 25 along this side edge.
is fixed, and in the center of this member 25,
The upper end of a connecting arm 27 having a long hole 26 extending vertically is fixed.

A pin fixed to a part of an endless chain 28 is loosely fitted into the elongated hole 26, and the endless chain 28 is stretched parallel to the transparent plate 22 between a pair of sprockets 30 and 31. There is.

On the other hand, the sprocket 31 is driven by a motor (not shown) via a suitable clutch in the direction of the arrow shown in the drawing during a copying operation.

A pin 29 is attached to the endless chain 2 on the original table 24.
By one rotation of the pin 8, only the horizontal vector of the pin 29 is transmitted, and the pin 29 moves back and forth from the rightward position shown in the figure. In each step of this reciprocating movement, when the pin 29 runs on the upper side of the chain, which is the tension side of the chain, it is the exposure process, and when the pin 29 runs on the lower side of the chain, it is the return of the original table 24. It has become a process.

The document mounting table 24 has a pin 29 fitted into the elongated hole 26 of the connecting arm 27 that is connected to the sprocket 3 on the right side in the figure.
When the pin 29 is located at the dead center 29A at the right end of 0, the starting position is determined, and when the pin 29 is located directly above the sprocket 30, the exposure opening position is determined.

Further, the stop position detection switch SW detects that the pin 29 is at the dead center at one end of the connecting arm 27.

This stop position detection switch SW is electrically connected to the original plate drive clutch, and disconnects the drive clutch when the pin 29 reaches the dead center 29A.

As described above, the document mounting table drive mechanism consisting of a chain loop mechanism does not require two clutches for driving in two directions, but only one clutch is required, and acceleration/deceleration at startup, direction change, and stop Since the above mechanism stops at the dead center position of the pin attached to the chain, self-locking is possible without the need for any special means to hold the document table in the starting position. can do. This self-lock has the feature that it can automatically hold the document in an immovable position against external forces applied to the document loading table, but it can also be used when moving the device, during maintenance inside the copying machine, or when paper jams occur inside the machine. When it is desired to move the original table in order to remove the document, the pin 29 is located at the dead center, so there is an inconvenience that it becomes impossible to move the document table even if an external force is directly applied to the table.

Therefore, in order to manually move the self-locked document tray without actuating the drive clutch, the drive pin is first released from the self-locked position using a lock release knob or lever, and the document tray can be manually freely moved. The object of the present invention is to provide a self-lock release device that is movable.

FIG. 2 shows the main parts of a lock release device for a document placing table (hereinafter referred to as a slider) according to the present invention. Note that among the members shown in FIG. 2, the same parts as in FIG. 1 are given the same reference numerals, and detailed explanation thereof will be omitted.

The sprocket 31 is supported by a shaft 31a, and a release knob 76 is attached to the other end of the shaft 31a, extending to an operable position via a spring clutch 75.

This spring clutch 75 is fitted around the shaft 31a, and one end is fixed to the release knob 76, and the release knob 76 allows the sprocket 31 to rotate in a normal direction (indicated by the arrow in FIG. 2). When the shaft 31a is rotated in a direction opposite to the direction indicated by A), the rotation is transmitted by the tightening action on the shaft 31a.

The reason why the release knob 76 is set in the opposite direction to the rotation direction of the regular sprocket is that when the slider that is not in the starting position is restarted by turning on the power switch (not shown) and automatically returns to the starting position, it will not move forward. This is because it takes the return route instead of passing through, thereby allowing the shortest travel distance and return in a short time. In addition, in the case where the image forming sequence is controlled by the position of the slider, an unnecessary copying process has to be performed by passing through the forward path, and therefore there is a problem that an unnecessary incomplete copy is made.

When the lock release knob 76 is turned in the direction of arrow D to rotate the sprocket 31, the endless chain 28
The pin 29 fixed to moves clockwise from the dead center 29A.

When the pin 29 is removed from the dead center 29A, the locking effect on the horizontal movement of the document placement table is released, so that the document placement table 24 can be moved by hand.

In FIG. 3, a connecting arm 2 having an elongated hole 26 that engages with a pin 29 fixed to an endless chain 28.
7, the long hole 26 is not just a long hole of the same width,
A recessed portion larger than the width of both ends is formed at the position where the pin 29 becomes the dead center. Leaf springs 77 are attached to both side edges of this elongated hole at intervals sufficient for the pin 29 to slide thereon (see FIG. 4).

The shape of the leaf spring 77 and the elongated hole is designed to prevent the pin 29 from being damaged due to the increased load on the pin 29 at the dead center when the slider 24 is manually returned suddenly. is set to prevent

That is, the leaf spring 77 is deflected by an external force, that is, an inertial force caused by the return of the slider 24, and as a result, the leaf spring 77 can absorb the inertial force that the pin 29 receives. Furthermore, slider 2
When the inertia force due to the return of the sprocket 4 cannot be absorbed by the leaf spring 77 alone, the load on the pin 29 is reduced by bending the leaf spring 77 and replacing it with a force that moves the connecting plate 27 out of the pitch circle of the sprocket. It is also possible. In this case, as shown in FIG.
The load on the pin 29 is reduced by abutting against the pin 29.

As described above, according to the present invention, by making use of the advantages of the scanning drive method using a chain loop, the self-lock, which is both an advantage and a disadvantage, can be manually released by simply providing a simple release knob. When the copying machine is not in use, the space occupied by the original table can be minimized, and maintenance inside the machine can be easily performed. Since the engine is on its way back to the starting position, various effects can be expected, such as being able to return to the starting position in the shortest distance without having to go through an extra round trip when restarting.

Although the pin 29 was removed from the dead center 29A by rotating the sprocket with the lock release knob 76, it is also possible to move the pin 29 directly by externally operating it. When the pin 29 is moved by external operation, press the release button 1 as shown in FIG.
When the pressing rod 100, which has a diameter of 00a and is vertically movably supported via a spring 101, is pushed in, its tip 100b pushes down the pin 29 and moves it away from the dead center 29A. It is also possible to move the pin 29 out of the dead center by rotating the sprocket shaft with a lever protruding from the cover of the main body of the copying machine.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of an electrophotographic copying machine in which the present invention is implemented, FIG. 2 is a schematic diagram showing one embodiment of the present invention, and FIG. 3 is a main part of another embodiment of the present invention. FIG. 4 is a perspective view showing a part of the present invention, and FIG. 5 is a partially enlarged view showing an example of the lock release operation section of the present invention. 24...Document mounting table, 28...Endless chain,
29...Pin, 30, 31...Sprocket, 3
1a... Support shaft, 75... Spring clutch, 7
6...Release knob, 100...Press rod.

Claims (1)

[Scope of Claims] 1. A scanning drive in which a document table placed slidably on the main body of an electrophotographic copying machine is reciprocated by a chain loop extending in parallel with the document table and driving in one direction. In the system, the original platen which is stopped is set at the dead center at the end of the chain loop, and the chain is manually moved slightly from the outside of the copying machine to remove it from the dead center, thereby moving the original platen. A slider lock release device equipped with a lock release member that allows manual movement. 2. An interlocking member is provided between the lock release member and the pin of the chain loop so that the pin moves away from the dead center only when the lock release member is rotated in the opposite direction to when the chain is activated. A slider lock release device according to claim 1.