JPH0538369Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a device for rotatably supporting a belt-shaped photoreceptor used in a copying machine or the like.

Prior Art A frame is provided with a holding roll, a drive roll, and a tension roll, and a belt-shaped photoreceptor is wound around each roll so that a constant tension is always applied to the belt-shaped photoreceptor by the tension roll. A support device is known in which a belt-shaped photoreceptor can be reliably rotated by a drive roll without slipping.

Problems that the invention aims to solve: Since a constant tension is always applied to the belt-shaped photoreceptor by a tension roll, if the belt-shaped photoreceptor is left stationary for a long time, The part of the belt-shaped photoreceptor that is in contact with the holding roll is strongly pressed by tension along the outer peripheral surface of the holding roll, and when it is separated from the holding roll, that part does not return to its straight state and becomes slightly curved. Therefore, when the belt-shaped photoreceptor rotates during a copying operation and is charged by a charger, the curved and deformed portion becomes uneven in distance from the charger, resulting in uneven The electrostatic charge causes uneven copy density, resulting in unsightly copies.

In order to make the belt-shaped photoreceptor replaceable, for example, as shown in FIG. When the movable frame c is rotated around the pin d, the frame a is folded, and the tension roll h is moved to the holding roll e side, so that the belt-shaped photoreceptor f can be easily removed and attached. , when rotating the movable frame c, the tension roll h
As the circumference of the belt-like photoreceptor f passes through the angle A° where the circumference is at its maximum, the tension spring g is compressed and the tension of the belt-like photoreceptor f increases, which becomes excessive than the actual tension. , belt-shaped photoreceptor f
may break or be damaged.

Means and action for solving the problem A mechanism is provided that biases the tension roll in the direction of increasing tension and moves the tension roll in the direction of decreasing tension against this biasing force, thereby preventing long-term suspension or replacement. At times, the tension on the belt-shaped photoreceptor can be reduced.

Example Frame 1 is fixed frame 2 and movable frame 3
The fixed frame 2 rotatably supports a holding roll 5 and a drive roll 6, and the movable frame 3 rotatably supports a tension roll 7. A belt-shaped photoreceptor 8 is rotatably wound around each roll.

Note that the fixed frame 2 and the movable frame 3 are composed of a pair of vertical plates, and each roll is rotatably supported between the pair of vertical plates.

The tension roll 7 is rotatably attached to a sliding block 10 that is fitted into and supported by a guide groove 9 opened at the front edge of the movable frame 3, and a rod 11 attached to this sliding block 10 is fixed to the movable frame 3. A compression coil spring 13 is slidably supported through the spring receiving plate 12, and a compression coil spring 13 extends between the spring receiving plate 12 and the sliding block 10.
is provided to urge the sliding block 10 forward,
This applies tension to the belt-shaped photoreceptor 8.

A cam 20 and a handle 21 are attached to the end of the pin 4.
A lever 22 is rotatably fitted to the lever 22. A link 23 is supported by the movable frame 3 on a support shaft 24 so as to be vertically movable below the lever 22. and the other side piece 23
b, and the other side piece 23b forms a substantially dogleg shape.
is loosely fitted into the end of the rod 11 and interferes with a stopper 25 provided at the end of the rod 11.

When the handle 21 is rotated upward from the state shown in FIGS. 1 and 2 and the cam 20 is rotated downward together with the lever 22, the cam surface of the cam 20
0a interferes with one side piece 23a of the link 23 to rotate the link 23 clockwise, and the other side piece 23b interferes with the stopper 25 to move the rod 11 to the right against the compression coil spring 13. .

As a result, the tension roll 7 moves to the right as shown in FIG. 3, so that no tension is applied to the belt-shaped photoreceptor 8, and the link 23 is held in this state by the cam 20.

In other words, as shown in Fig. 4, the compression coil spring 1
3, the link 23 is given a rotational force in the direction of the arrow about the support shaft 24, so that the one side piece 23a of the link 23 comes into contact with the cam surface 20a of the cam 20,
The cam 20 attempts to rotate in the direction of the arrow around the pin 4, but it passes through the center 4' of the pin 4 and the one side piece 2
Q is the intersection of the straight line
The point where the boundary between the two sides touches the one side piece 23a is S, and since the straight line connecting the pin center 4' and the point S is longer than the straight line connecting the pin center 4' and the Q point, the rotation of the link 23 is Since the cam 20 is not rotated by power, it is maintained in the state shown in FIG. 3.

In this way, by rotating the handle 21 upward, the tension on the belt-shaped photoreceptor 8 is eased, and the handle 21 is rotated upward.
1 can be rotated downward to increase the tension of the belt-shaped photoreceptor 8, so that the part of the belt-shaped photoreceptor 8 that is in contact with the holding roll is deformed when the copying machine is stopped for a long period of time. In addition to preventing the movable frame 3 from being unable to be restored to its original state, the movable frame 3 can be
When rotating upward around , the tension of the belt-shaped photoreceptor 8 has already been reduced, so the belt-shaped photoreceptor 8 can be broken without the tension of the belt-shaped photoreceptor 8 becoming excessive than the actual tension. It can be replaced without damage or damage.

Effect of the invention By forming the flat surface 20c on the cam 20, the flat surface 2
When 0c comes into contact with one side piece 23a of the link 23, the link 23 is engaged and held to hold the sliding block in the tension reducing position of the belt-shaped photoreceptor 8, so the tension of the tension roll is reduced. When the copying machine, etc. is not in use for a long period of time, the tension is weakened and the part of the belt-shaped photoreceptor that contacts the holding roll etc. is bent and deformed, returning to its original state. This structure prevents the movable frame 3 from being unable to return to its original state, and allows the handle 21 to be rotated to rotate the movable frame 3 relative to the fixed frame while maintaining the state of engagement between the cam 20 and the link 23. , the tension roll can be moved in the direction of decreasing tension, and while maintaining that state, the movable frame 3 can be rotated and bent against the fixed frame, and the actual tension can be adjusted when replacing the belt-shaped photoreceptor. Since no excessive tension is applied, the belt-shaped photoreceptor does not break or break.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of the present invention, FIG. 2 is a plan view of the part shown in FIG. FIG. 5 is an explanatory diagram of defects in the conventional example. 1 is a frame, 5 is a holding roll, 6 is a drive roll, 7 is a tension roll, and 8 is a belt-shaped photoreceptor.

Claims (1)

[Scope of utility model registration request] The frame 1 is composed of a fixed frame 2 and a movable frame 3 rotatably connected to the fixed frame 2 via a pin 4.The fixed frame 2 is provided with a holding roll 5 and a driving roll 6, and the movable frame 3 is A tension roll 7 is provided via a slidably supported sliding block 10, and a belt-shaped photoreceptor 8 is rotatably wound around each roll, and the sliding block 10 is attached to the movable frame 3. A cam 20 and a handle 21 that rotates integrally with the cam 20 are pivotally supported on the pin 4, and the movable frame 3 connect the link 23 to the pin 4
The handle 21 is rotatably supported in a different position from the handle 21.
The rotation of the cam 20 rotates the link 23 via the cam 20 so that the sliding block 10 is moved in the direction of reducing the tension of the belt-shaped photoreceptor 8.
When a flat surface 20c is formed on the link 20 and the flat surface 20c comes into contact with the one side piece 23a of the link 23, the link 2
3 is engaged and held to hold the sliding block 10 in the tension reducing position of the belt-shaped photoreceptor 8, and the handle 21 is rotated while the cam 20 and the link 23 are kept engaged to move the slide block 10. frame 3
A support device for a belt-shaped photoreceptor, characterized in that it is configured to rotate with respect to the fixed frame 2.