JPH02169423A - Paper feeding device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper feeding device used in an image forming apparatus or the like, and particularly to a suction cup type device.

[Prior Art] In image forming apparatuses and the like, a device that feeds stacked sheets one by one is equipped with a half-moon-shaped separation roller made of a rubber material or the like, and utilizes the difference in the coefficient of friction between the paper and the separation roller. Generally used is a method in which the topmost sheet is separated by one sheet and conveyed to a predetermined position.

However, in this paper feeding method, when separating the uppermost paper from the stacked papers, the following phenomenon occurs because the difference in the coefficient of friction between the roller and the paper and between the papers and the paper is used.

When the separation roller and the back side of the paper come into contact, the front side of the first sheet of paper and the back side of the second sheet of paper rub against each other, and a portion of the first sheet of paper is peeled off. Therefore, for example, if the paper is color developer paper coated with a color developer, traces of the peeling will remain on the output image, degrading the image quality. On the other hand, if the separation roller and the developer surface are in contact with each other, slipping occurs between the roller and the developer surface during separation. As a result, the color developer peels off, resulting in a decrease in image quality as described above.

In addition to the method of separating and feeding paper using differences in friction coefficients as described above, there is a device that uses negative pressure to suck paper with a suction cup and feed paper, for example, in Japanese Patent Laid-Open No. 55-937.
It is known as shown in No. 44. However, although the method shown in this publication solves the above problem,
In order to separate the paper, a structure is used in which air is ejected toward the gap between the paper sheets, and a white board on which the paper sheets are stacked is moved up and down, which requires a large-scale agitation. Not only does this go against labor-saving measures, but the paper leaves tend to scatter.

In addition, the leading edge of the paper can be nipped by the paper feed roller only when the white board descends while the paper is being sucked by the suction cup and the suction cup moves laterally. There are problems with paper feed reliability.

The present invention was made to solve the above problems, and
With an extremely simple configuration, the paper does not scatter or bend.
Without damaging the top sheet of stacked paper,
It is an object of the present invention to provide a paper feeding device that can separate and feed paper reliably.

[Means for Solving the Problems] The present invention provides a plurality of suction cups that are provided on the uppermost paper surface of sheets stored in a stacked manner in a paper cassette so as to be able to be closely spaced from each other;
In a paper feeding device that includes means for bringing the suction cup into close contact with the uppermost paper surface, and a decompression means for reducing the pressure between the suction cup and the paper to negative pressure, the suction cup has a means for raising the suction cup in a state where the suction cup is sucking the paper, and a suction cup. The device is provided with a means located near the leading edge of the paper that has been suctioned and lifted by the apparatus to nip the leading edge and feed the paper into the paper transport path.

[Function] According to the above configuration, the paper on the eroded part of the stacked paper is sucked by the suction cup, and then the suction cup is raised from that state, so that the paper is strained, causing the paper to bend, and the paper on the topmost paper to be bent. A gap is created between the second and subsequent sheets of paper, and only the topmost sheet of paper remains on the suction cup side. Therefore, since the sheets do not rub against each other, it is possible to separate the sheets without damaging the paper surface. Moreover, in the raised state, the leading edge of the sheet is immediately nipped into the feeding means such as a sheet feeding roller. Therefore, the paper can be fed without falling on the way.

Embodiment The paper feeding device of the present invention will be described below with reference to FIG. 1, which shows the schematic configuration of an embodiment of a photosensitive and pressure-sensitive copying machine equipped with the device and capable of full-color copying. do.

The photosensitive pressure sensitive copying machine 1 of this embodiment uses photosensitive paper consisting of photosensitive pressure sensitive paper (microcapsule paper) and developer paper (paper). A movable document table glass 2 and document table cover 3 are provided on the top plate of the copying machine 1, and a desired document 4 is set face down on the document table glass 2.

A light source using a halogen lamp 5 or the like is installed at the top of the copying machine 1, and it irradiates light in a line through a slit hole provided on the top surface of the machine toward the document table glass 2, and emits light from the halogen lamp 5. The fallen light is transmitted through the transparent document glass 2 and reflected by the document 4 placed thereon.

Therefore, exposure scanning of the original 4 is performed by moving the original platen glass 2. The light reflected from the original 4 passes through a filter 6 for adjusting the color tone of the copied image and enters a projection lens 7, and the direction of the light projected by this lens 7 is changed by a pair of reflection mirrors 8.9. , an image is formed on the microcapsule paper 11 located along the exposure stage 10. The reflecting mirror 8.9 is mounted on a mirror mounting plate, and the optical path and focus can be adjusted by finely adjusting the mounting position of the mirror mounting plate.

On the other hand, a long microcapsule paper 11 is wound around a cartridge shaft 12 and housed in a cartridge that can be stored in and removed from the machine, and one end of the paper is wrapped around a cartridge shaft 12.
4a, 14b, 14c, a pressure developing device 'J113, and a separation mechanism 14d to reach the winding shaft 15. That is,
The microcapsule paper 11 that comes out from the lower part of the cartridge is guided by a feed roller 14a and a kite roller 14b, passes under the exposure table 10, is supplied to a pressure developing device 13, and further passes through this pressure developing device 13. The microcapsule paper 11 that is
It can be rolled up on top. Note that the unexposed microcapsule paper 11 after leaving the cartridge is maintained in an unexposed state by the light shielding cover. Further, the conveyance speed of the microcapsule paper 11 is controlled to be constant, and the document platen glass 2
Since the moving speed is made to match the moving speed of the document, latent images of predetermined lines of the document are sequentially formed on the microcapsule paper 11 as it passes through the exposure table 10.

A paper feed cassette 17 containing developer paper (paper) 16 constituting the paper feed device is installed below the pressure developing device 13, and a suction cup-type paper feed mechanism 18 that sucks paper using negative pressure suction. is provided, and the developer paper 16 is fed by a paper feed mechanism 18.
The sheets are picked up one by one by the feed roller 19a and the pinch roller 19b, and then transferred to the developing paper rollers 19c and 1.
After the leading end is aligned by the resist gate 9d and the resist gate 19e, it is carried into the pressure developing device 13.

In this way, the pressure developing device 13 contains the microcapsule paper 1.
1 and the developer paper 16 are supplied in close contact with each other and are integrated, and the microcapsule surface of the microcapsule paper 11 on which the latent image is formed is in contact with the developer-coated surface of the developer paper 16 on the inside. The roller 13b is then sandwiched between the small diameter roller 13a and the backup roller 13b, and pressure is applied thereto. This pressure destroys the unexposed microcapsules and forms an image on the color developing paper 16.

After the microcapsule paper 11 and the color developer paper 16 that have come out of the pressure development device 13 are separated by a separation mechanism 14d, the color development of the color developer paper 16 is promoted by the heat roller 20a of the heat fixing device 20, and an image is formed. After that, the paper is delivered to a paper ejection tray 21 by a paper ejection roller. Note that the separated microcapsule paper 11 is wound onto the winding shaft 15 via the meandering adjustment roller 14e.

Next, the configuration of the paper feed device consisting of the above-mentioned suction cup type paper feed R side 18 will be explained with reference to FIG.

A paper placement plate 22 is housed in the paper feed cassette 17, and the color developing paper 16 is stacked on this placement plate 22. on the other hand,
Paper feeder Ift! ! Reference numeral 18 includes a suction cup 23 and a lift R structure 24 that moves the suction cup 23 up and down in the up and down (arrows in the figure) direction by a driving source not shown.The suction cup 23 is connected to a negative pressure source not shown through a pipe 25. It is connected. Also, sucker 23
A paper uppermost surface detection sensor 26 made of a microswitch or the like is provided in the vicinity of the suction cup at the same horizontal position as the suction cup. In addition, the suction cup 31 is arranged so that it can attract the color developer paper 16 at a relatively front portion with respect to the front and rear of the conveyance direction of the color developer paper 16.

Regarding the configuration on the paper conveyance path side, a feed roller 19 is placed above the leading end of the color developing paper 16 stacked in the paper feed cassette I 17.
a, and a pinch roller 19b that moves toward and away from the roller 19a rotates around a shaft 27.
It is pivotally supported at the tip of 8. The rotating arm 28 is rotated by a drive source (not shown) every time a sheet is fed, and the rollers 19a,
19b is opened and closed. Furthermore, a kite member 29 forming a conveyance path toward the pressure developing device 13 is disposed on the downstream side in the conveyance direction of the color developer paper, and a color developer paper roller 19 is disposed in the middle thereof.
c, 19d and resist gate 19e are provided.

Further, in order to avoid interference with the feed roller 19a and the like when the suction cup 23 is raised, a plurality of small suction cups 23 arranged in parallel is suitable.

In addition, by using a large number of suction cups in this way, it is possible to obtain a large suction force as a whole with a small negative pressure for each suction cup, which is better for obtaining the separation effect using a paper strainer. Are suitable.

Next, to explain the paper suction operation of this device, the suction cup 23
When the suction cup 23 is lowered by the operation of the elevating mechanism 24 and the sensor 26 detects the uppermost surface of the paper, the elevating mechanism 24 is stopped to stop the suction cup 23 from descending. At this time, the suction cup 23 comes into close contact with the surface of the uppermost color developing paper 16, and is in a state where it can suck the paper.

In this state, a pressure reducing means (not shown) is driven to generate negative pressure in the suction cup 23, and the suction cup 23 suctions the topmost color developing paper 16.Next, from this suctioned state, the suction cup 23 is raised to a predetermined height. Raise it to this position and stop. This predetermined height position is the height at which the leading edge of the paper is located directly below the feed roller 19a. Subsequently, the pinch roller 19b is rotated in the direction of the arrow, and the pinch roller 1 shown by the two-dot chain line is connected to the feed roller 19a.
9b), then stop the suction of the color developing paper 16 by the suction cup 23, and
Release the developer paper 16 from the.

As mentioned above, when the developing paper 16 is subjected to suction and lifting action by the suction cup 23, only one sheet is separated by the action of the paper strainer and fed into the conveyance path. the feed roller 1 until it hits the registration gate 19e.
9a and pinch roller 19b, the leading edge of the paper is aligned and the skew is corrected, and then, at a predetermined timing, the registration gate 19e is opened and the developing paper 16 is transported.

Note that the paper feeding device of the present invention is not limited to application to the copying machine configured in the above embodiment, but can be applied to image forming devices using various types of photosensitive and pressure sensitive paper, and As for each mechanism constituting the paper feeding device, various actual configurations are possible. For example, a piston mechanism or a crank mechanism may be used as the pressure reducing means.

[Effects of the Invention] As described above, according to the present invention, there is a paper feeding device that feeds the topmost sheet of stacked sheets using a suction cup, and separating and feeding the sheets is performed by the upward movement of the suction cup. It can be done only with
Since the paper is not separated by friction, the paper can be reliably fed one by one without damaging the paper or degrading the image quality.

Furthermore, compared to a method in which air is blown out to separate the paper, the structure can be made smaller with a simpler structure, double feeding can be prevented, and the paper will not be scattered. Further, by having a structure in which the suction cup side is moved up and down relative to the stacked paper side, there is an advantage that the mechanism can save labor compared to a structure in which the paper side is moved.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a copying machine equipped with a paper feeding device according to an embodiment of the present invention, and FIG. 2 is a schematic side sectional view of the same paper feeding device. 16... Developing paper (paper), 17... Paper feed cassette,
18... Paper feeding mechanism, 19a... Feed roller, 19b
... Pinch roller, 23 ... Suction cup, 24 ... Lifting mechanism. Figure 1

Claims (1)

[Claims] (1) A plurality of suction cups installed so as to be closely spaced from each other on the uppermost paper surface of sheets stored in a stack in a paper cassette, a means for bringing the suction cups into close contact with the uppermost paper surface, and a means for controlling the pressure between the suction cups and the paper. A paper feeding device equipped with a decompression means for creating a negative pressure, a means for raising the suction cup in a state where the suction cup is sucking the paper, and a means for raising the suction cup in a state where the paper is sucked by the suction cup, and a means located near the leading end of the paper sucked and raised by the suction cup. and a means for nipping the leading end of the paper and feeding the paper into a paper transport path.