JP2842480B2 - Paper feeder - Google Patents

Description

The present invention can be applied to a recording apparatus such as a printer, a copying machine, a facsimile, a printing machine, etc., which records on paper by printing, transferring, copying, printing and the like. More specifically, the present invention relates to a sheet feeding device that feeds out sheets in a sheet storage container such as a sheet feeding tray one by one in such a recording apparatus.

2. Description of the Related Art Conventionally, as shown in FIG. 5, a sheet holder of this type includes a pad holder 1 on which a friction pad 1a is provided. 2, the paper feed roller 2 is rotated to feed the paper P in the paper feed tray 3 between the paper feed roller 2 and the friction pad 1a, and the paper is fed while the double feed is prevented by the friction pad 1a. (See Japanese Patent Application Laid-Open
No. 56-141238). In another sheet feeding device, a separation roller 6 is pressed by a spring 5 against a feed roller 4 that rotates clockwise as shown by an arrow in FIG. 6, and the separation roller 6 is normally driven to rotate counterclockwise. However, when the paper P is multi-fed by the pickup roller 7, the separation roller 4 is independently rotated clockwise as shown by an arrow in the drawing, and the second and subsequent papers P are returned to the paper feed tray 3 and separated. There is also a configuration in which paper is fed while feeding (see Japanese Patent Application Laid-Open No. 59-64442). Further, as shown in FIG. 7 and FIG. 8, the sheet feeding device for feeding the sheet P between the two rollers while preventing the double feed from being fed includes a blocking roller 8 and a separating roller 9. And the rollers 8 and 9 are respectively
8a ・ 9a and roller body 8b ・ 9d
A plurality of roller portions 8c
There is a configuration in which a roller 9c is formed and the roller portions 8c and 9c are arranged so as to bite each other. Then, the separation roller 9 is rotated to sequentially send out the sheets P stacked on the sheet feed tray 3 from below, and is formed into a waveform between the separation roller 9 and the blocking roller 8. The paper P is pressed against the separation roller 9 by its stiffness and fed by the rotation of the separation roller 9, and the second and subsequent sheets P are pressed against the inhibition roller 8 by their stiffness, and The paper is returned to the paper feed tray 3 side by the rotation of, thereby feeding the paper while preventing double feed (see Japanese Patent Application Laid-Open No. 57-72538).

Problems to be Solved by the Invention However, among the conventional paper feeders described above, some paper feeders have a problem that the friction pad 1a generates uneven friction at the leading end of the paper or the like during long use. Although the paper feeder described above does not have much problem with abrasion resistance, it has a problem that the structure is complicated and the cost is high. The paper feeder at that point has a relatively simple structure, but since it has a lower paper feed type configuration in which the loaded paper is sequentially pulled out from the bottom and sent out, the weight of the loaded paper loaded on the lowermost paper is reduced. A large rotation load is applied to the separation roller 9. for that reason,
There is a problem that a driving device such as a motor for the separation roller becomes large.

Accordingly, an object of the present invention is to make it possible to reduce the rotational load of the separation roller in the above-described paper feeding apparatus, to have a simple structure, to have good wear resistance, and to keep costs low.

Means for Solving the Problems Therefore, the present invention according to claim 1 has a separation roller having a plurality of roller portions 41a and 52a spaced from a roller shaft 40 and 51, for example, as shown in the following illustrated embodiments. 35 and a blocking roller 50 are provided with their roller portions 41a and 52a biting each other.
In the sheet feeding device 20 that feeds out the paper 19 in the paper storage container such as 18 and feeds the paper while preventing the double feed by the blocking roller 50, the separation roller 35 is moved to the uppermost paper 19 in the paper storage container. And the blocking roller
50, a torque limiter 54 provided between the roller portion 52a and the roller shaft 51 to apply a constant rotational load to the roller portion 52a, between the retracted position and the positioning position of the separation roller 35 on the roller shaft 40. The positioning rollers 42, 42 that define the bite amount y of the roller portion 41a of the separation roller 35 and the roller portion 52a of the blocking roller 50, and bias the positioning rollers 42, 42 to the retracted position. And a side plate 4 having an elongated hole 45a for guiding the roller shaft 51 of the blocking roller 50, and fixing the blocking roller 50.
And a supporting member such as (5).

According to the first aspect of the present invention, the separation roller 35 is rotated to feed out the sheet 19 in the paper storage container, and the first sheet 19 is fed by the rotation of the separation roller 35, and the second sheet 19 is fed. The paper 19 is stopped by the blocking roller 50 to prevent double feeding. After the first sheet 19 is fed, the second sheet 19 is fed by the separation roller 35. In addition, when the last sheet 19 is sent out of the paper container by the separation roller 35, the blocking roller
The last sheet 19 is fed by the driven rotation of 50.

When the blocking roller 50 is fixed to the support member, the positioning rollers 42 are moved from the retracted position to the positioning position against the urging means, and the outer peripheral surfaces 42a
2a is brought into contact with the outer peripheral surface of the roller portion 52a of the blocking roller 50 to define the bite amount y. Then, the roller shaft 51 of the blocking roller 50 is fixed to the support member. After the blocking roller 50 is fixed, the positioning roller 42 is returned to the original retracted position by the urging means.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 3 shows an overall schematic configuration of an internal mechanism of a laser printer to which the present invention is applied. What is indicated by reference numeral 10 in the drawing is a printer main body. The printer body 10 includes a belt traveling device 11 in the center of the inside. The belt traveling device 11 has a wide and endless photosensitive belt 14 stretched between a driving roller 12 and two driven rollers 13. Although not shown, the rotation from the drive source is transmitted to drive the drive roller 12.
To rotate the photoreceptor belt 14 in the direction indicated by the arrow in FIG. Then the charger 15
Then, the surface of the photoreceptor belt 14 is uniformly charged, written by a laser writer 16 to form an electrostatic latent image on the surface, and developed by a developing unit 17 to visualize the latent image. On the other hand, a paper feed cassette 26 for main paper feed is provided on the right side of the printer main body 10 in the drawing, and a paper feed tray (paper storage container) 18 for simple paper feed is detachably mounted on the right side. And
For example, paper 19 such as postcards stored in the paper feed tray 18
Are sequentially fed one by one by the sheet feeding device 20 of the present invention, and the leading ends are abutted between a pair of registration rollers 21 to be stopped.
Then, the registration rollers 21 and 21 are rotated in synchronization with the visible image on the photoreceptor belt 14 described above,
The paper 19 is guided between the photoreceptor belt 14 and the transfer device 22. As a result, the visible image on the photoreceptor belt 14 is transferred to the upper surface of the sheet 19 by the transfer unit 22 and sent to the fixing unit 23 where the transferred image is fixed. After that, the sheet 19 after the fixing is discharged to the sheet discharge unit 24 on the printer main body 10. On the other hand, the photoreceptor belt after transfer
In 14, the surface is cleaned by the cleaning device 25, and is uniformly charged again by the charging device 15.

By the way, the paper feed tray 18 in the illustrated laser printer
, As shown in FIG. 4, the sheets 19 are stacked on the bottom plate 30. The bottom plate 30 is provided with a friction plate 31 on the upper surface at the front end (left end in the figure), and is attached to the paper feed tray 18 so as to be rotatable about a support shaft 32 provided at the rear end. And α ₁
To the pivotable alpha ₂ angular range. For example, the angle is set to about 15 degrees when paper is not loaded, and is set to about 30 degrees when paper is loaded at the maximum.
Further, the bottom plate 30 is pushed up by a compression spring 33 provided at the bottom of the sheet feeding tray 18 so that the top sheet 19 is fed to the sheet feeding device of the present invention.
It is pressed against the separation roller 35 in 20. Then, the separation roller 35 is rotated to automatically send out the paper 19 sequentially from the top. In the paper feed tray 18, the bottom plate 30 is tilted in accordance with the change in the amount of loaded paper, so that the separation roller
The feeding pressure (kgf) for 35 is always kept almost constant. The reference numeral 36 in the drawing indicates a manual feed tray.

In addition, the separation roller 35 in the sheet feeding device 20 of the present invention.
Specifically, as shown in FIG. 1, a roller shaft 40 and a roller body 41 provided at the center of the roller shaft 40 are formed, and a plurality of roller portions 41a are formed on the outer periphery of the roller body 41. Become. The roller portion 41a protrudes in the radial direction of the roller main body 41 and is provided at intervals in the axial direction. Further, positioning rollers 42, 42 are fitted to both ends of the roller shaft 40 of the separation roller 35, and the positioning rollers 42, 42 are retracted as shown in FIG. It is provided movably between The outer peripheral surfaces 42a of the positioning rollers 42 are formed of a resin (nylon, polyacetal or the like) having low friction (about 0.1 to 0.3 μ). A spring (biasing means) 43 is wound around the roller shaft 40 between the positioning roller 42 and the roller body 41, and the positioning roller 42
42 is always urged to the retreat position. The separation roller 35 has a gear 44 attached to the right end of the roller shaft 40 in FIG. 1, transmits the rotation of a drive motor (not shown) to the gear 44, and is rotatably supported by a side plate (support member) 45. Become. Further, in the sheet feeding device 20 of the present invention, the blocking roll 50 is provided below the separation roller 35. The blocking roller 50 includes a roller shaft 51 and a roller body 52 provided at the center of the roller shaft 51 so as to be rotatable about the roller shaft 51. A plurality of roller portions 52a are formed on the outer periphery of the roller body 52. Become. The roller portion 52a protrudes in the radial direction of the roller body 52 and is provided at an interval in the axial direction. In addition, this blocking roller
As shown in FIG. 2, 50 is a roller body 52 and a roller shaft.
A torque limiter 54 for applying a constant rotational load to the bearing 53 and the roller body 52 is provided on each of the left and right sides in the figure between the bearings 51 and 51. Then, the roller portion 52a of the blocking roller 50 and the separation roller 35
The roller portion 41a is bitten and arranged, and both ends of the roller shaft 51 are passed through a long hole 45a formed in the side plate 45 and held by the side plate 45. Then, as shown in FIG.
The roller 42 moves from the retracted position to the positioning position against the spring 43 so that the outer peripheral surfaces 42a of the positioning rollers 42 contact the outer peripheral surfaces of the left and right side roller portions 52a of the blocking roller 50 in the drawing. At that time, the E-ring 55 is inserted into the roller shaft 41 while holding the bent portion 55a of the E-ring 55, and the positioning rollers 42, 42 are temporarily fixed at this positioning position. Then, the roller portions 41a and 52a are brought into a fixed bite amount y (1 + 0.1 m
m to about 1-0.3 mm). Then, the roller part 41
In the state where a. 52a has bitten by the biting amount y, both ends of the roller shaft 51 are screwed to the side plate 45, thereby supporting the blocking roller 50. After the blocking roller 50 is fixed, the E-ring 55 is removed, and the positioning rollers 42 are returned to the original retracted position by the spring 43. Then, the E-ring 55 is inserted into the roller shaft 51 again to prevent the positioning rollers 42 from coming off at the retracted position. Reference numeral 56 in FIG. 2 denotes an E-ring for preventing the roller body 52 of the blocking roller 50 from coming off.

Now, as shown in FIG. 2, the separation roller 35 is rotated clockwise to separate the paper 19 in the sheet feed tray 18 from the separation roller 35.
And is sent out in a waveform between the block roller 50 and the block roller 50. At this time, for example, when the sheets 19 are sent in an overlapped manner, the first sheet 19 presses against the separation roller 35 with its stiffness, and is fed by the rotation of the separation roller 35. On the other hand, the second sheet 19
Is the blocking roller fixed by the torque limiter 54
The roller body 52 is pressed against the roller body 52 with the strength of the waist and stopped by friction between the roller body 52 and the roller body 52. Then, after the first sheet 19 is fed, the sheet is fed by rotation of the separation roller 35. Thus,
The sheet is sequentially fed one by one by the separation roller 35 while the double feed is blocked by the blocking roller 50. Thereafter, when the last sheet 19 in the paper feed tray 18 is sent out by the rotation of the separation roller 35, the rotational force is transmitted to the blocking roller 50 via the sheet 19, and the blocking roller 50 is rotated by the rotating force. The paper 19 is fed by rotating following the load.

Effects of the Invention Therefore, according to the present invention, the separation roller and the blocking roller do not come into contact with each other, and the rollers are bitten and arranged, and the blocking roller in the normally fixed state is rotated at the time of the last paper. In addition, the rotational load of the separation roller can always be reduced, and the structure is simple, the wear resistance is good, and the cost can be reduced.

Further, since the separating roller is provided with the positioning roller for adjusting the biting amount of the separation roller and the blocking roller, there is an effect that the biting amount can be easily adjusted.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a sheet feeding device according to an embodiment of the present invention, in which a part thereof is disassembled and a sheet feeding tray is partially cut away;
FIG. 2 is a partial cross-sectional view of both rollers for explaining the adjustment of the amount of biting between the separation roller and the blocking roller. FIG. 3 is an overall schematic configuration diagram showing the internal mechanism of a laser printer having the paper feeding device of the present invention. FIG. 4 is an enlarged sectional view of a sheet feeding tray and a part of the apparatus main body to which the sheet feeding tray is attached. FIG. 5 is a sectional view showing a conventional paper feeder of a friction pad type,
FIG. 6 is a cross-sectional view showing a conventional sheet feeding device which prevents double feeding with two rollers, FIG. 7 is a side view showing a conventional sheet feeding device of a lower sheet feeding type and a roller biting type, and FIG. FIG. 4 is a front view showing a bite arrangement of two rollers in the sheet feeding device. 18 Paper feed tray (paper storage container) 19 Paper 20 Paper feeder 35 Separation rollers 40, 51 Roller shaft 41a / 52a Roller part 42 Positioning roller 43 Spring Energizing means) 45 Side plate (supporting member) 45a Slot 50 Blocking roller 54 Torque limiter y Biting amount

Claims (1)

(57) [Claims] A separation roller having a plurality of roller portions and a blocking roller having a plurality of roller portions at intervals on a roller shaft are provided so that the roller portions bite each other, and the separation roller feeds out a sheet in a sheet storage container. In a sheet feeding device for feeding a sheet while preventing a double feed with a blocking roller, the separation roller is provided in contact with a topmost sheet in the sheet storage container, and a separation roller is provided between a roller portion of the blocking roller and a roller shaft. And a torque limiter for applying a constant rotational load to the roller portion. The torque limiter is provided movably between a retracted position and a positioning position on the roller shaft of the separation roller, and the roller portion of the separation roller and the blocking roller are provided. Positioning roller for defining the amount of biting of the roller portion, biasing means for biasing the positioning roller to the retracted position, and a long hole for guiding the roller shaft of the blocking roller Has become a support member for fixing the blocking roller, the paper feeding device.