JP2000095354A - Paper feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeder capable of easily and surely determining the neutral position of a return lever, improving the sure operation of the return lever, and stabilizing the paper feed operation. SOLUTION: This paper feeder is provided with a paper feed roller 1 rotated to feed paper sheets during the paper feed operation, a hopper 2 in which a plurality of paper sheets to be fed by the paper feed roller are stacked in an inclined condition and a part in the vicinity of a tip of a forward side of the paper sheet is pressed against the paper feed roller during the paper feed operation, a separation pad 9 which is urged toward the paper feed roller 1 to separate the paper sheet to be fed by the paper feed roller 1 from a next paper sheet by hold-pressing the paper sheet between the paper feed roller and the pad, and a return lever 20 to press and return the paper sheet reaching the separation pad surface prior to the paper feed operation by the paper feed roller to the hopper. The neutral position of the return lever is determined by the tension of a tensile spring 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeder suitable for a printer or the like, and more particularly to paper stacked on a hopper in an inclined state, for example, plain paper, coated paper, OHP (overhead projector) sheet, glossy paper. And a sheet feeder for feeding cut sheets such as glossy films or envelopes one by one from the uppermost position.

[0002]

2. Description of the Related Art The applicant of the present invention has previously filed an application of this type of paper feeder which has a return lever for pushing back a paper reaching a separation pad surface to a hopper prior to the start of a paper feeding operation. (Japanese Patent Application Nos. 9-304857 and 9-304858). This return lever
The neutral position of the return lever is set by a torsion spring.

[0003]

However, since the torsion spring uses the spring force in the torsion direction, it is easily affected by the shape accuracy (machining accuracy) at the time of manufacturing the torsion spring, and the setting of the neutral position is simple. There is no problem. In practice, large variations of ± 30 degrees are inevitable. Therefore, there is a possibility that the operation of the return lever is not highly reliable, and the sheet feeding operation becomes unstable.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet feeder which can easily and reliably determine the neutral position of the return lever, thereby improving the reliability of the operation of the return lever, and stabilizing the sheet feeding operation. Is to do.

[0005]

In order to achieve the above object, the invention according to the first aspect of the present invention provides a paper feed roller which rotates during a paper feed operation and feeds a paper, and a paper feed roller which feeds the paper. A plurality of sheets to be fed are stacked in an inclined state, and a hopper that presses the vicinity of the front end of the sheet toward the sheet feeding roller that rotates during a sheet feeding operation, and a sheet hopper that is pressed toward the sheet feeding roller. The paper is pressed between the paper feed roller and the paper feed roller to separate the paper to be fed by the paper feed roller from the next paper. A return lever for pushing back the sheet reaching the separation pad surface to the hopper, wherein the return lever is set at a neutral position by a tension force of a tension spring. Device.

According to the present invention, the neutral position of the return lever is determined by the tension of the tension spring. The neutral position of the tension spring can be easily set because the neutral position is determined by the positions of the spring hooks at both ends even if the spring force varies.

According to a second aspect of the present invention, in the paper feeder according to the first aspect, the return lever is rotatably supported at its free end by a base end so as to be rotatable. The neutral position of the return lever is determined in a state where the distance between the first hook for hook provided at the end and the second hook for spring provided on the main body frame is shortest. Things. According to the present invention, if the spring is assembled in a tensioned state, the distance between the first hook for spring hooking and the second hook for spring hooking will always be the shortest, so that the neutral position of the return lever can be reliably set. Can be set. In particular, according to the present invention, there is an effect that there is no need to be affected by the variation in the magnitude of the spring force.

According to a third aspect of the present invention, in the paper feeder according to the first or second aspect, the tension spring is substantially parallel to a main body frame surface located below the hopper and the separation pad. It is characterized by being provided. ADVANTAGE OF THE INVENTION According to this invention, when providing a tension spring, since a little space on a main-body frame surface can be utilized effectively, it does not need to enlarge.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of a sheet feeding device according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of a return lever portion of the sheet feeding device.

As shown in FIG. 1, in the paper feeder according to the present embodiment, a plurality of sheets P to be fed by a D-shaped paper feed roller 1 are stacked on a hopper 2 in an inclined state. ing. The hopper 2 is rotated by a hopper spring (not shown) with a base end positioned above the fulcrum at a lower end thereof, and rotated by a hopper spring (not shown). , The vicinity of the front end of the paper P is brought into pressure contact. Further, a leading end support surface 4 on which the paper P stacked in an inclined state on the hopper 2 is supported by abutting the leading end 3 thereof is provided near the front of the hopper 2. At the rear of the hopper 2, a paper support (not shown) is detachably attached to the frame body.
It is designed to support the rear side.

A separation pad 9 is provided facing the paper feed roller 1 and urged toward the paper feed roller 1 by a pad spring (not shown). The paper P is conveyed between the separation pad 9 and the paper feed roller 1 by pressure so as to separate the paper to be fed by the paper feed roller 1 from the next paper. . In the drawing, reference numeral 14 denotes an idle roller.

In the present embodiment, the vicinity of the leading end 3 of the paper P is urged toward the paper supporting surface 7 of the hopper 2 so that the leading end 3 of the paper P contacts the leading end supporting surface 4 in a downward state. An urging member 15 is provided. In this embodiment, as shown in FIG. 1, the urging member 15 is made of a synthetic resin sheet, and the upper end thereof is
6 is fixed to a guide 17 attached to the guide 6.

Further, as shown in FIG. 1, the sheet P2 reaching the surface of the separation pad 9 is pushed back to the sheet supporting surface 7 of the hopper 2 prior to the sheet feeding operation by the sheet feeding roller 1. The return lever 20 is provided in a state where the neutral position is determined by the tension of the tension spring 21. In the present embodiment, the return lever 20 has a free end 22 pivotally supported at a base end 23 so as to be freely rotatable, and a first spring hook 24 provided at a base end 23 of the return lever 20. The neutral position (the position in FIG. 1) of the return lever 20 is determined in a state where the distance between the second lever 26 and the second hook 26 provided on the sub-frame 25 in this example is the shortest. Further, in the present embodiment, the tension spring 21 is disposed substantially parallel to the surface of the sub-frame 25 located below the hopper 2 and the separation pad 9.

In the present embodiment, an operating member 30 for applying a rotating force to the return lever 20 is fixed to the paper feed roller shaft 13 to which the paper feed roller 1 is fixed, in the vicinity of the paper feed roller 1. . When the paper feed roller shaft 13 rotates (reversely rotates) in the counterclockwise direction in FIG. 1 by receiving the power of a drive motor (not shown) prior to the paper feed operation, the return lever 20 enters the recess 31 of the action member 30. To rotate to the position indicated by the two-dot chain line shown in FIG. The sheet P2 that has reached the surface of the separation pad 9 by this rotation is returned to the hopper 2. Thereafter, the paper feed roller shaft 13 is rotated clockwise (forward rotation) by the power of the drive motor 34 to return the return lever 20 to the neutral position side, and to start a new paper feed operation. .

In the present embodiment, the return lever 20
At the time of rotation of the return lever 20, the projection cam 27 pushes the projection piece 28 of another member,
The other member is made to perform a certain operation. This allows the other member to perform the certain operation with increased reliability based on the fact that the neutral position of the return lever 20 can be set accurately. In this example, the other member is a separation lever (not shown) for separating the separation pad 9 from the idle roller 14, and is arranged on the lower surface of the separation pad 9. In FIG. 2, reference numeral 29 denotes a hole in which a hopper spring is provided.

Next, the operation of the paper feeder according to the above embodiment will be described with reference to FIG. According to the present embodiment, since the return position of the return lever 20 is determined by the pulling force of the tension spring 21, the neutral position is determined by the positions of the hooks at both ends of the spring. Can be set to the neutral position. Therefore, the positional relationship with the operation member 30 during the sheet returning operation can be easily determined with high accuracy, and the sheet returning operation can be reliably and stably performed.

A free end side 22 of the return lever 20 is rotatably supported at a base end 23, and a first hook 24 for spring hook provided on the base end 23 of the return lever 20 and a main body frame. When the neutral position of the return lever 20 is determined in a state where the distance from the second hook 26 is shortest, the first hook for the spring is always provided if the spring is assembled in a tensioned state. Since the distance between the hook 24 and the second hook for hooking 26 is minimized, the neutral position of the return lever 20 can be reliably set.

Also, the tension spring 21 is mounted on the main frame 25 below the hopper 2 and the separation pad 9.
When the tension spring 21 is provided, a small space on the main body frame surface can be effectively used when the tension spring 21 is provided, so that there is no need to increase the size.

[0019]

According to the present invention, the neutral position of the return lever can be easily and reliably determined, thereby improving the reliability of the operation of the return lever and stabilizing the sheet feeding operation. . That is, according to the present invention, the neutral position is determined by the pulling force of the return lever using the tension spring, so that the neutral position can be easily and reliably set.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a sheet feeding device according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a return lever portion of the paper feeding device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 paper feed roller 2 hopper 3 leading edge of paper 4 leading edge supporting surface 7 hopper paper supporting surface 9 separation pad 15 biasing means 20 return lever 21 tension spring 22 free end side 23 base end side 24 first hook 25 for spring hook 25 sub Frame (body frame) 26 Second hook for spring hook 30 Working member P Paper P2 Paper pushed back

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3F343 FA02 FA09 FB02 FB04 FC01 FC06 GA03 GB01 GC01 GD01 HA14 HB03 HD18 JD03 JD08 JD33 LA04 LA15 LC11 LC19 LD04

Claims (3)

[Claims] 1. A paper feed roller which rotates during a paper feed operation and feeds paper, and a plurality of sheets to be fed by the paper feed roller are stacked in an inclined state and rotated during the paper feed operation. A hopper that presses the vicinity of the front end of the paper toward the paper feed roller; and urges the paper toward the paper feed roller to squeeze the paper between the paper feed roller. A separation pad for separating the sheet to be fed by a roller from a next sheet, and a return lever for pushing back the sheet reaching the separation pad surface to the hopper prior to a sheet feeding operation by a sheet feeding roller. And a neutral position of the return lever is determined by a tension force of a tension spring. 2. The return lever according to claim 1, wherein the free end is rotatably supported at the base end so as to be freely rotatable, and is provided on the first hook for hooking provided at the base end of the return lever and the main body frame. The neutral position of the return lever is determined in a state where the distance from the second hook for hooking is shortest. 3. The sheet feeding device according to claim 1, wherein the extension spring is disposed substantially parallel to a main body frame surface located below the hopper and the separation pad.