JPH0720779B2 - Paper feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] A pick arm is rotatably provided on a shaft provided on a frame, and a pick roller facing an end of a hopper that stacks sheets is rotatably provided on a rotary end of the pick arm. In the paper feeding device provided in the above, even if the thickness of the paper changes, the pressure contact force by the pick roller is changed so that the paper can be smoothly fed in order to prevent the paper feeding failure. It is a paper feeding device.

[Industrial application field]

The present invention relates to a paper feeding device that supplies paper to a printer that forms a part of an information processing device, and in particular so that paper can be supplied smoothly even when the paper thickness changes. The present invention relates to a sheet feeding device formed so that the pressure contact force of a pick roller can be changed.

[Conventional technology]

In a printer that forms part of a conventional information processing apparatus, when printing on a single-cut sheet, one sheet is extracted from a hopper in which the sheets are stacked by a pick roller, and the sheet is fed to a printing unit of the printer. Paper equipment is in use.

FIG. 7 is a principal part explanatory view showing an example of a printer which is the object of the present invention. In FIG. 7, reference numeral 1 denotes a sheet feeding device, which mainly has a hopper 3 on which sheets 2 are stacked and a pick roller 4 for extracting one sheet 2 from each sheet. Reference numeral 5 denotes a printing device, which is composed of a print head 6, a platen 7, a paper feed roller 8, a paper passage 9, and the like. A stacker 10 stacks the printed sheets 2.

The paper 2 extracted by the pick roller 4 in FIG. 7 is fed in the paper passage 9 by the paper feed roller 8, printed between the print head 6 and the platen 7, and fed in the paper 9 by the paper feed roller 8. Sent, stacker
Stacked to 10.

Next, FIG. 8 is an explanatory view of the main parts of the sheet feeding device in the conventional example shown in FIG. 7, and the same parts are designated by the same reference numerals as those in FIG. In FIG. 8, a pick arm 11 is rotatably provided on a shaft 13 provided on the frame 12, and a pick roller 4 rotatably provided at a turning end of the pick arm 11 is provided inside the hopper 3. It is configured so as to face the sheets 2 stacked on each other. Reference numeral 14 denotes a separation pad, which is formed so as to be rotatable with respect to the pick arm 11 and to be pressed against the rotation downstream side of the pick roller 4 via a spring 15.

With the above configuration, the pick roller 4 rotating in the arrow direction
The uppermost sheet 2 extracted by is fed to the left,
The paper feed roller 8 moves in the paper passage 9. In this case, the separation pad 14 has a function of preventing the inconvenience of feeding a plurality of sheets 2 and separating one sheet 2.

[Problems to be Solved by the Invention]

In the above-mentioned conventional paper feeding device, since the press contact force is applied to the sheets 2 stacked in the hopper 3 by the weight of the pick roller 4, the press contact force is formed to be substantially constant. ing. On the other hand, in recent printers, printing is performed on a wide variety of media such as high quality paper of 45 to 220 kg / ream, Kent paper, copy paper (carbonless paper) and envelopes. Therefore, there is a problem in that it is difficult to smoothly feed these various types of sheets and media, depending on the sheet feeding device having a substantially constant pressure contact force. That is, when the pressure contact force is set to be relatively large,
Although it is possible to smoothly feed thick paper, the handling of thin paper becomes too strong, and in particular, when copying paper is fed, there is a problem that the parts forming the copying paper are separated from each other. . On the other hand, when the pressure contact force is made small, it is suitable for thin paper, but it becomes impossible to extract thick paper, and the pick roller 4 runs idle. As described above, the conventional sheet feeding device has a problem that it is difficult to smoothly feed a sheet of 45 to 220 kg / ream since the pressure contact force is substantially constant or in an extremely narrow range.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems existing in the above-mentioned conventional apparatus, and to provide a paper feeding apparatus that can feed paper smoothly and reliably even when the paper has a relatively wide thickness.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, in the present invention, a pick arm is rotatably provided on a shaft provided on a frame, and a pick roller facing the end of a hopper on which sheets are stacked is provided at a turning end of the pick arm. In a rotatably provided sheet feeding device, a pick arm is provided with an operating piece provided with a spring for rotating the pick arm in a direction opposite to a direction in which the pick arm is rotated by its own weight, and a hopper provided on a frame. A top sensor for detecting the upper end and an actuating plate formed so as to be disengageable are respectively provided, an actuating member formed so as to be disengageable with the actuating piece is provided at a free end, and the pick arm is caused by the weight of the pick roller. A pressure arm provided with another spring is rotatably provided so as to rotate in the same direction as the rotation direction, and the combined torque of the weight of the pick roller and the operating piece provided with the spring is provided. Is configured so that the combined torque and the superimposed torque of the torque of the pressure arm with another spring interposed act selectively on the pick arm, and the pressure contact force of the pick roller against the paper is made variable. We adopted the technical means of doing.

[Action]

With the above configuration, when the pressure contact force of the pick roller with respect to the paper is increased, if the hopper on which the paper is stacked is raised, the operating piece provided on the pick arm and the operating member provided on the pressure arm are brought into contact with each other. The spring interposed in the pressure arm acts to rotate the pick arm in the same direction as the rotation direction of the pick roller due to the weight of the pick roller, and the pressure contact force of the pick roller with respect to the sheet can be increased.

〔Example〕

FIG. 1 is an explanatory view of essential parts showing an embodiment of the present invention, FIG. 2 is a view taken in the direction of arrow A in FIG. 1, FIG. 3 is a view taken in the direction of arrow B in FIG. The same reference numerals as in the figure are used. In FIGS. 1 to 3, reference numeral 16 denotes an actuating arm, which is formed in a substantially L-shape and is fixed to a shaft 13 forming the center of rotation of the pick arm 11 so that the pick arm 11 can rotate integrally. Form. 16a is an actuating plate, and the frame 12
The top sensor 17 is fixed to the top sensor 17 and has a U-shaped cross section for detecting the upper end position of the hobba 3. 16b is an actuating piece, which is provided with a spring 18
The pulling force acts to rotate the actuating arm 16 and the pick arm 11 in the counterclockwise direction, that is, in the direction opposite to the direction in which the pick roller 4 rotates due to its own weight. Next, 19 is a pressure arm, which is provided with an actuating member 20 at its free end and is rotatably provided on a shaft 21 fixed to the frame 12. Reference numeral 22 denotes a spring, which is interposed in the pressure arm 19 and is formed so as to rotate the pressure arm 19 counterclockwise. A stopper 23 is fixed to the frame 12 and is an operating member of the pressure arm 19.
It is provided so that it can be engaged with and disengaged from, and the rotation of the pressure arm 19 in the counterclockwise direction is stopped at a predetermined position. A pick sensor 24 is provided on the path of the pick arm 11 through which the sheet 2 passes, and forms the front end and the rear end of the sheet 2 in a detectable manner. Note that θ ₁ and θ ₂ are the operating plate 16a and the operating piece 1
The working angle is 6b, and it is formed so that θ ₁ > θ ₂ .

Next, the operation of the above configuration will be described. First, when the hopper 3 on which the sheets 2 are stacked is lifted in the frame 12, the upper end of the sheets 2 contacts the pick roller 4 and the pick arm 11 is rotated counterclockwise, so that the operating plate 16a and the top sensor 17 are connected. Engage and stop in the state shown in FIG.
In this state, the self-weight of the pick roller 4 and the tensile force of the spring 18 are substantially balanced, that is, the torque of the self-weight of the pick roller 4 and the operating piece 16 of the spring 18.
The combined torque with the torque for b acts on the pick arm 11, and the pick roller 4 exerts a predetermined pressure contact force on the sheet 2. Therefore, the paper 2 can be fed leftward by rotating the pick roller 4 clockwise as shown in FIG. The separating / separating action of the sheet 2 by the separating pad 14 is the same as that of the conventional example shown in FIG.

Next, when the paper thickness of the paper 2 becomes large, when the paper 2 is not fed even when the pick roller 4 is rotated by a predetermined number of pulses, that is, the leading edge of the paper 2 is detected by the pick sensor 24. If not, the pick roller 4 is stopped and the hopper 3 is raised by a predetermined amount.
When the hopper 3 moves up, the pick arm 11 rotates counterclockwise, and at the same time, the operating arm 16 also rotates counterclockwise. When the rotation angle becomes larger than the operating angle θ _{2, the} pick arm 11 is provided on the operating arm 16. The actuating piece 16b comes into contact with the actuating member 20 provided at the free end of the pressing arm 19 to rotate the pressing arm 19 slightly clockwise. Since the operating member 20 is separated from the stopper 23 by the above rotation of the pressure arm 19, the tensile force due to the expansion of the spring 22 is transmitted to the operating piece 16b via the operating member 20. That is, the superimposed torque of the combined torque due to the weight of the pick roller 4 and the tensile force of the spring 18 and the torque of the pressing arm 19 due to the tensile force of the spring 22 acts on the pick arm 11 via the operating piece 16b. Therefore, the torque for rotating the actuating arm 16 and the pick arm 11 in the clockwise direction acts, and the pressure contact force of the pick roller 4 with respect to the sheet 2 is increased. Due to the above action, the thick paper 2
It is possible to selectively increase the pressure contact force of and to smoothly feed the paper.

FIG. 4 is a flow chart of an embodiment of the present invention, and the processing procedure in the above embodiment will be described with FIG. 1 with reference to FIG. First, the process is started (40) by an execution command from the main body device (not shown). Next, when the hopper 3 is raised (41) and the top sensor 17 is closed (42), the hopper 3 is stopped (43) in the state shown in FIG. When the hopper 3 moves up and the predetermined number of hopper pulses is exceeded (44), the hopper 3 is stopped (57) and END (58) to perform another process. When this state is formed, the pick roller 4
By rotation (45), the paper 2 shown in FIG. 1 is extracted and fed, and the paper 2 further advances to close the pick sensor 24 (46).
After that, the pick roller 4 is rotated a certain amount (47), and when the feeding of the paper 2 is completed, the pick roller 4 stops (4
8). After that, printing on paper 2 is completed (49)
After that, if the next printing is continued (50), the process of pick roller 4 rotations (45) or less is repeated to feed the paper 2 again, and if the printing is not continued (50), END (58 )
Becomes

On the other hand, for example, when the thickness of the paper 2 becomes large, if the paper 2 is not fed even if the pick roller 4 shown in FIG. 1 rotates, that is, if the paper 2 does not reach the pick sensor 24, In Figure 4, pick sensor 24 closed (46)
However, the number of pick roller pulses exceeds a predetermined number (51), and the pick roller 4 is stopped (52). In this case, when the paper 2 is not stacked in the hopper 3, the hopper is empty (53).
Set as END (58) to replenish other items and perform other processing. On the other hand, if the paper 2 is not fed even though the paper 2 is stacked and not in the hopper empty (53), the pick roller 4
Assuming that the hopper 3 is raised (54) and the top sensor 17 is closed (55) in order to increase the pressure contact force due to
The hopper 3 continues to rise until the number of hopper pulses exceeds a predetermined number (56), the hopper is stopped (57), and END (58) is reached. By this process, the pick arm 11 in FIG.
And the operating arm 16 rotates counterclockwise, and the operating piece 16b
Since the operating member 20 and the operating member 20 contact each other to rotate the pressure arm 19 in the clockwise direction, the pressing force of the pick roller 4 can be increased by extending the spring 22, as described above. After that, the processing of four rotations of the pick roller (45) or less shown in FIG. 4 is executed with the increased pressure contact force. On the other hand, when the operating piece 16b shown in FIG. 1 rotates beyond the top sensor 17 when the hopper 3 continues to rise (54), the condition of closing the top sensor 17 (55) in FIG. The hopper 3 is stopped (57) and END (58) is set. That is, the hopper 3 shown in FIG. 1 is continuously raised to prevent the pressure contact force of the pick roller 4 against the sheet 2 from becoming abnormally large.

FIG. 5 is a cross-sectional view of essential parts showing another embodiment of the present invention,
The same parts are designated by the same reference numerals as those in FIGS. 1 and 8. In FIG. 5, reference numeral 25 is a stopper, which is provided on the pick arm 11 so as to be detachable from the separation pad 14 so as to regulate the rotation angle of the separation pad 14.

With the above configuration, the sheets 2 stacked on the hopper 3
Even when the paper thickness is large, the rotation of the separation pad 14 is restricted within a certain angle by the stopper 25, and the inconvenience of a plurality of sheets 2 entering can be prevented. Also a separation pad
Since the spring constant of the spring 15 that acts so as to press 14 against the pick roller 4 can be reduced, it is possible to prevent the inconvenience of separating the parts even when the copy paper is fed.

FIG. 6 is an explanatory view of the operation of the embodiment shown in FIG. 5, and the same parts are designated by the same reference numerals as in FIG. FIG. 6 shows a state in which the thick paper 2 is between the pick roller 4 and the separation pad 14, and the separation pad 14 is in contact with the stopper 25. As shown in FIG. 6, the paper 2 having a large paper thickness comes into contact with the pick roller 4 at a winding angle θ due to the so-called “waist” strength of the thick paper. Therefore, the spring 15 shown in FIG.
Even if the spring constant of the sheet is small, the feeding force for the sheet 2 can be increased, and the force of biting the sheet 2 by the sheet feeding roller 8 (see FIG. 5) disposed on the downstream side of the sheet 2 Can improve.

In this embodiment, an example in which the operating plate 16a and the operating piece 16b of the operating arm 16 which rotates integrally with the pick arm 11 form a substantially L-shape in FIG. 1 has been described, but other shapes may be formed. However, the operation is the same as long as the top sensor 17 and the pressure arm 19 are formed so as to be detachable. Further, in the embodiment shown in FIG. 1, the stopper 25 shown in FIG. 5 may be additionally provided.

〔The invention's effect〕

Since the present invention has the configuration and operation as described above, the pressure contact force of the pick roller with respect to the paper can be made variable, and it is possible to change from thin paper such as carbonless paper or copy paper to Kent paper or high-quality paper. Paper with a wide range of paper thicknesses, including thick paper, can be reliably handled without paper jams and can be smoothly fed.

[Brief description of drawings]

FIG. 1 is an explanatory view of essential parts showing an embodiment of the present invention, FIG. 2 and FIG. 3 are views as seen from arrows A and B in FIG. 1, and FIG. 4 is a flow chart of an embodiment of the present invention. , FIG. 5 is a sectional view showing the principal part of another embodiment of the present invention, FIG. 6 is an explanatory view of the operation of the other embodiment of the present invention, and FIG. 7 is an example of a printer which is the object of the present invention. FIG. 8 is a principal part explanatory view showing a sheet feeding device in a conventional example. 2: Paper, 3: Hopper, 4: Pick roller, 11: Pick arm, 16:
Actuating arm, 16a: Actuating plate, 16b: Actuating piece, 17: Top sensor, 1
9: Pressure arm, 20: Actuating member, 23, 25: Stopper.

Claims (1)

[Claims] 1. A paper feed comprising a pick arm rotatably provided on a shaft provided on a frame, and a pick roller rotatably provided at a turning end of the pick arm to face an end of a hopper stacking sheets. In the device, the pick arm has a spring-mounted operating piece for rotating the pick arm in a direction opposite to the direction in which the pick roller rotates due to its own weight, and a top sensor provided on the frame and for detecting the upper end of the hopper. And an actuating plate formed so as to be disengageable, an actuating member formed so as to be disengageable with the actuating piece at a free end, and the pick arm is rotated in the same direction as the rotation direction of the pick roller due to its own weight. A pressure arm having another spring interposed is rotatably provided so as to move, and the combined torque of the pick roller's own weight and the operating piece provided with the spring or this combined torque and another spring is interposed. A sheet feeding device, characterized in that it is formed such that a torque superimposed on a torque of a mounted pressure arm acts selectively on a pick arm, and a pressure contact force of a pick roller with respect to a sheet is made variable.