JPS6141334Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a sheet holding device for a drum.

A drum sheet that automatically wraps and holds the sheet material around the drum in devices such as facsimile machines and mimeograph machines that wrap sheet materials such as paper or film (such as manuscripts) around the drum for reading and recording. It is well known to provide retaining devices. This type of device grips the leading edge of the sheet material being fed in with its claws, and after gripping, the claws rotate as the drum rotates, and at this time, the claws have sufficient elasticity with the drum circumferential surface. After passing under the presser bar that is in contact with the presser bar, the sheet member held by the claws is squeezed by the presser bar and wound so as to be in close contact with the circumferential surface of the drum, and the end of the sheet member is placed under the presser bar. A drum sheet holding device has already been proposed in which the stopper that fixes the presser bar is engaged and disengaged when the presser bar reaches the end of the sheet member, and the presser bar presses the end of the sheet member.

In such a device, the claws strongly grip the sheet member, and the presser bar has sufficient elasticity to overcome the claws, and when the sheet member is brought into close contact with the drum and squeezed, the sheet member is not damaged. The surface of the sheet member must be as smooth as possible, and when the end of the sheet member is pressed, it must be pressed with such force that it will not peel off due to the rotation of the drum.

However, it is very difficult to fully satisfy these requirements with conventional devices.For example, when the sheet member is a photoreceptor film, the presser bar is made of a metal leaf spring, which is easily damaged and can cause damage to the back. A weak sheet member is easily damaged, and the sheet member attached to the circumferential surface of the drum often loosens after the drum rotates. Furthermore, if the elasticity of the holding member is made stronger to prevent the sheet from loosening, it will be difficult for the pawl to pass through, so it is possible to make the pawl thinner, but when a relatively heavy sheet member is held in the grip, There was a drawback that the sheet member came off during drum rotation.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned conventional drawbacks and provide a drum sheet holding device that can safely and reliably attach and hold various sheet members on the drum.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In FIGS. 1 and 2, 1 is a drum, 2 is a sheet member to be wrapped around the drum peripheral surface 1a, 3 is a clamp member with a claw 4 formed at one end, and the other end of the clamp member 3 is attached to the drum 1. The other end of a tension spring 5, which has one end fixed to the drive shaft 1b, is fixed, and the clamp member 3 is given an elastic action that constantly pulls it toward the center of the drum. The clamp member 3 includes
A roller 6 is attached, and the roller 6 is in contact with the circumferential surface of the cam 7. This contact is ensured by the elastic action of the tension spring 5, so that the clamp member 3 is moved as the drum 1 rotates. Cam 7
Follow. The cam 7 is connected to the drum drive shaft 1b via a low friction coefficient or a friction clutch,
Normally, it rotates along with the rotation of the drive shaft 1b, but
Cam stopper 9 is attached to pin 8 attached to cam 7.
is stationary when engaged.

A sliding ring 10 is fitted around both ends of the drum 1 with a relatively weak force, and the sliding ring 10 normally rotates with the rotation of the drum. When the stopper 12 is engaged, it is stationary. A presser bar 13 is fixed to the sliding ring 10.

As shown in FIG. 3, the presser bar 13 has an elastic member configured as a chevron-shaped leaf spring 15 fixed to the support plate 14 at its top portion, and has elongated holes 1 at each hem.
5a is formed, and a pin 16 is fitted into the elongated hole 15a. This pin 16 is the presser plate 1
The holding plate 17 is made up of a base plate 18, a rubber member 19, and a flexible member 20 that is soft and has a small coefficient of friction, and the flexible member 20 is made of, for example, felt, leather, or the like.

The present invention is constructed as described above, and its operation mode is as follows.

FIG. 2a is a diagram showing a standby state, in which the clamp member 3 is lifted by the roller 6 in contact with the large diameter portion 7a of the cam 7, and is stationary with the claw 4 open. Further, the cam 7 is also stationary due to the engagement of the cam stopper 9 with the pin 8. In this state, the sheet member 2 is fed in the direction of arrow B by the paper feed roller 21, and when the tip of the sheet member 2 eventually enters the open claw 4, a detection device (not shown) detects this, and the drum 1 begins to rotate in the direction A, the clamp member 3 also rotates, and the roller 6 comes off from the cam 7. Therefore, the clamp member 3 is pulled toward the center of the drum by the elastic action of the tension spring 5, and the claw 4 grips the tip of the sheet member. This grip is completed C
At this position, the cam stopper 9 is disengaged from the pin 8, and the cam 7 is rotated along with the rotation of the drum drive shaft 1b.

At this time, the pin 11 of the sliding ring 10 is engaged with the ring stopper 12 and the sliding ring 10 is stationary, and therefore the presser bar 13 is also stationary. As the drum 1 rotates, the pawl 4 passes under the presser bar 13, but the presser bar of this embodiment has a leaf spring 15 and a rubber material 19 and has sufficient elasticity, so that the pawl 4 does not pass under the presser bar 13. Even if the thickness is increased, the presser bar 13 can easily get over the claw (FIG. 2b). When the pawl 4 passes the presser bar 13, the sheet member 2 whose tip is held by the pawl 4 is squeezed by the presser bar 13. A flexible member is provided, and even if the sheet member 2 is a photoreceptor film, it will not be scratched. When the end of the sheet member 2 reaches approximately the C position,
The ring stopper 12 is disengaged from the pin 11, and the sliding ring 10 rotates as the drum 1 rotates.
The end of the sheet member 2 is held down by a holding bar 13.

According to the above configuration, the presser bar 13 of this example has sufficient elasticity and a flexible member is attached to the surface facing the drum surface, so the claws 4 can be made thick and strong. Moreover, the problem of any kind of sheet member being damaged is eliminated.

FIG. 4 shows another embodiment of the present invention, in which the claws 4 have thick parts 4a and thin parts 4b arranged alternately at predetermined intervals, and the presser bar 13 is a presser bar. The plate 17 is divided, and the claw 4 is the presser bar 1.
3, the holding plate 17 is arranged so as to go over the thin part 4b of the claw. With this configuration, the claws 4 can be made stronger, and no matter how heavy the sheet member 2 is attached, it will not come off.

By configuring the present invention as described above, it has a special effect in that sheet members of various strengths and weights can be mounted reliably without being damaged.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view showing an embodiment of a drum sheet holding device according to the present invention, FIG. 2a is an explanatory diagram showing the embodiment shown in FIG. 1 in a sheet loading standby state, and FIG. Fig. 1 is an explanatory diagram showing the sheet being installed; Fig. 3 is a partial sectional view showing a part of the presser bar;
FIG. 4 is a partial perspective view showing another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Drum, 2...Sheet member, 3...Clamp member, 4...Claw, 4a...Thickness part, 4b...
Thin part, 13... Presser bar, 14... Support plate, 15
...Elastic member, 17... Presser plate, 20... Flexible member.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A clamp member equipped with a claw that grips the tip of the sheet member, and a presser lever that is capable of getting over the claw and that holds the sheet member in close contact with the drum circumference. In the drum sheet holding device, the pawl has thick parts and thin parts alternately formed in the axial direction of the drum, and the presser lever supports a presser plate that comes into contact with the sheet member and the presser plate. 1. The sheet holding device, characterized in that the sheet holding device is provided with a support plate, and is arranged in sections such that when the claw and the presser lever intersect, the presser member passes through the thin part of the claw. (2) The sheet holding device according to claim 1, wherein an elastic member is interposed between the support plate and the presser plate. (3) The sheet holding device according to claim 1 or 2, wherein a flexible member is provided on the surface of the presser plate that comes into contact with the drum peripheral surface.