JPS609790Y2 - Copy machine roll paper drawer - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a roll paper pull-out device for a copying machine.

When using a roll of photosensitive paper, copy paper, etc. in a copying machine, the rotation of the roll is braked to pull out the paper in a taut state.

One control method is to use spring force to apply frictional braking to the outside diameter of the roll, but the larger the roll diameter, the more the spring stretches and the greater the braking force. The disadvantage is that the braking force increases, and as the diameter decreases, the variation in braking force becomes large.

There is also a method of applying frictional braking by applying the force of a fixed weight to the surface of the roll, but this method has the disadvantage that it is not possible to eliminate fluctuations in the braking force at the bearing portion caused by fluctuations in the roll diameter.

In order to eliminate the fluctuations, it is possible to reduce the shaft diameter and use a ball bearing for the bearing, but there are problems in terms of strength and axial mobility, so it is difficult to eliminate the fluctuations in the braking force at the bearing part. Can not.

Furthermore, there is a method in which a brake is applied to the shaft, but this method has the disadvantage that the braking force is insufficient.

The object of the present invention is to provide a roll paper pull-out device that applies a constant braking force to keep the paper pack tension constant regardless of changes in roll diameter due to paper pull-out.

To achieve this goal, the present invention utilizes a combination of the braking force generated in the bearing and the additional frictional braking force applied to the outer surface of the roll, and uses a weight to control the change in the braking force of the bearing, which varies in proportion to the roll diameter. This was achieved by a braking device that compensated for the additional frictional braking force caused by the lever by changing the position of the weight, thereby always achieving a constant braking force as a whole.

The details of the present invention will be explained with reference to embodiments shown in the figures.

In FIG. 1, a light image of a document on a document table 1 is exposed by an illumination exposure device 2 onto a photosensitive paper 4 that has been charged in advance by a charger 3, thereby forming an electrostatic latent image.

During exposure, the original and the photosensitive paper 4 are moved synchronously.

The photosensitive paper 4 is then pulled out from the roll 5 under a constant tension by a pull-out device.

In the case of a color original, a latent image of a color-separated light image is formed on the photosensitive paper 4, and the latent image is developed in a corresponding color by a wet type developing device 6.

The developed toner image on the photosensitive paper is transferred to a transfer sheet 7.

The transfer sheet 7 is fixedly wrapped around the transfer drum 8,
During rotation, the charger 9 pre-charges the pre-wet liquid, which is made of the same liquid as the developer solvent, to the pre-wetter 1.
It is pre-wetted by applying 0 and transferred by coming into contact with the photosensitive paper 4 at the transfer position.

The transferred transfer paper 7 is fixed by a fixing device 21, and the above steps are repeated to transfer a plurality of separated color images in a superimposed manner.

After the transfer, the photosensitive paper 4 is wound up by a winder 12 rotated by a support roller 11.

A copying machine having such a structure allows large-sized color copies to be obtained as accurate images.

- For example, a pull-out device for a roll 5 of photosensitive paper in a copying machine as shown in FIG. 1 rotatably supports a core shaft 13 attached to a roll 5 of photosensitive paper 4 as shown in FIGS. 2 and 3. a braking device 15 that applies braking force to the bearing 14 and the roll 5;
and has.

The braking device 15 includes a lever 17 supported by a support shaft 16 so as to be tiltable up and down, a braking pad 18 that brakes the rotation of the roll 5 by friction in contact with the surface of the roll 5 fixed to the lever 17, and a brake pad 18 attached to the lever 17. It has a weight 19.

A guide groove 20 is formed in the lever 17, and the weight 19 is supported so as to be freely movable along the guide groove 20.

As shown in FIG. 2, when the roll diameter of the roll 5 is maximum, the lever 17 tilts around the support shaft 16 to the uppermost position, and the weight 1
9 is located at the bottom end, at the left end of the figure, due to its own weight.

When the winding diameter of the roll 5 is maximum, the frictional force generated on the bearing 14 due to the roll's own weight is maximum, but the weight 19 is
8, the frictional braking force by the weight 19 is the minimum.

As the paper is pulled out and the diameter of the roll 5 decreases, the lever 17 tilts downward.

That is, the inclination angle of the lever 17 gradually decreases.

Therefore, the weight 19 gradually moves toward the center of the lever 17.

At this time, the moving distance of the weight is selected so that the braking force by the weight 19 increases by a force corresponding to the reduction in the braking force in the bearing 14 due to the decrease in the winding diameter, and the weight 19 automatically moves to the selected position by its own weight. The shape of the guide groove 20, for example, the radius R when forming it as an arc, is selected so as to.

When the winding diameter of the roll 5 reaches an intermediate value, the lever 17 is set to be in a substantially horizontal state as shown in FIG. 4, and the weight 19 is set to be located at a substantially intermediate position of the movement range.

When the winding diameter further decreases to the minimum winding diameter, the lever 17 continues to tilt downward as shown in FIG. The shape of the guide groove 20 is set so that the gravitational frictional force due to the gravitational force reaches the maximum position.

When the braking force exerted by the weight 19 becomes maximum, the winding diameter of the roll 5 becomes the minimum and its own weight becomes small, so that the frictional braking force in the bearing 14 becomes the minimum.

As described above, due to the decrease in the winding diameter of the roll 5, the sum of the braking force at the bearing 14, which decreases, and the frictional braking force due to the weight 19, which increases due to the decrease in the winding diameter of the roll 5, becomes approximately equal at every moment. The length of the lever 17 and the weight of the weight 19 are selected as follows.

Weight 19 was set in consideration of the change in the pulling force due to the change in the radius of the roll.
The weight of the guide groove 20 and the shape of the guide groove 20 are selected.

The simplest shape of the guide groove 20 is a circular arc, but any curved line can be selected so that the position of the weight 19 is at the lowest position of the curve depending on the change in the lever inclination angle.

With this invention, it is possible to compensate for changes in the power on the bearing side due to changes in the weight of the roll with a simple structure, and it has become possible to always apply a constant tension to the paper as back tension.

The roll paper can be used not only for photosensitive paper but also for transfer paper.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an example of a copying machine using the drawer device according to the present invention, FIG. 2 is a front view of the drawer device according to the present invention, FIG. 3 is a plan view of FIG. 2, and FIGS. FIG. 5 is a diagram corresponding to FIG. 2, and shows the intermediate and minimum winding diameters, respectively. 4...Photosensitive paper, 5...Roll, 13.
... Core shaft, 14 ... Bearing, 15 ...
...braking device, 16... spindle, 17...
Rubber, 18...Brake pad, 19...
- Weight, 20... Guide groove.

Claims (1)

[Scope of utility model registration request] A roll paper drawer for a copying machine that pulls out the paper while applying back tension has a bearing that rotatably supports the roll paper and a control device that frictionally brakes the rotation of the roll paper, and the control device can be tilted up and down by a support shaft. A lever supported by a lever, a braking pad fixed to the tip of the lever and arranged so as to be in contact with the surface of the roll paper, and a weight movably supported by the lever are included, and the weight is transferred and guided to the lever. A guide is provided, and the guide is formed in a curved shape such that the weight automatically moves according to a change in the inclination angle of the lever to a position where the frictional braking force is increased by the braking force that decreases in the bearing due to a decrease in the roll diameter. A roll paper drawer for a copying machine, characterized in that: