JPH01118467A - Automatic sheet feeder - Google Patents

Abstract

PURPOSE:To prevent double sheets from being fed by providing a control circuit of an actuator for isolating a sheet feed roller from a sheet on the basis of a command signal for detecting that the sheet is fed at a predetermined distance by the roller. CONSTITUTION:A control circuit 54 inputs a sheet feed command signal from a printer 52 and a detection signal for detecting that a sheet 2 arrives at a sheet feed roller 53. When the sheet feed command signal is input to the control circuit 54 upon starting of printing, the sheet feed command is output to a driver circuit 56 to start normally rotating a pulse motor 42. Thus, a sheet feed roller 35 is rotated to engage the uppermost sheet 22 of laminated sheets 2 between the roller 35 and a friction pad 47. When the end is completely engaged with the roller 53, a detection signal is output to the circuit 54, a stop command is fed to the circuit 56. Thus, a pulse motor 42 is stopped, and the roller 35 is isolated at an interval d1 from the laminated sheets on an elevation base 23.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an automatic paper feeding device applied to laser printers and other page links, and in particular, the present invention relates to an automatic paper feeding device that is applied to laser printers and other page links, and in particular, the present invention relates to an automatic paper feeding device that is applied to laser printers and other page links, and in particular, the present invention relates to an automatic paper feeding device that is applied to laser printers and other page links. The present invention relates to an automatic sheet feeder that separates and feeds sheets.

[Conventional technology]

Razor printers and other page printers employ automatic paper feeding devices of a friction separation paper feeding type that have a relatively simple structure.

FIGS. 8(a) and 8(b) are side views of main parts of a conventional automatic paper feeder.

In the figure, reference numeral 1 denotes an elevating table on which a large number of sheets 2 of various sizes such as A4, 84, etc. are stacked. This elevating table 1 is supported by a vertical guide member 3 so as to be movable up and down. Reference numeral 4 denotes a rope for raising and lowering the lifting platform 1. Its lower end is connected to the lifting platform 1, and the other end is wrapped around a fixed pulley 5 attached to the upper end of the guide member 3, and is composed of a hoisting drum (not shown) or the like. It is connected to a hoisting drive mechanism. Reference numeral 6 denotes a paper feed roller located above the guide member 3 and arranged horizontally.
A one-way clutch 8 is attached to the drive shaft 7 rotating in the direction of arrow A.
It is attached via. Reference numeral 9 denotes a friction pad disposed along the outer periphery of the paper feed roller 6, which is made of cork, rubber, or the like having a friction coefficient smaller than the surface friction coefficient of the paper feed roller 6.

In the conventional automatic paper feeder configured as described above,
When feeding sheets of paper 2 on the elevating table 1 to a printer (not shown), the elevating table 1 is raised and held so that the upper end of the stacked paper is pressed against the lower surface of the paper feed roller 6. .

In this state, when the drive device (not shown) is activated in response to a paper feed command and the drive shaft 7 is rotated in the direction of the arrow in FIG. 8(a), the paper feed roller connected via the one-way clutch 8 6
also rotate in the same direction. Along with this, the uppermost paper 2° of the stacked paper 2 pressed against the paper feed roller 6 is transferred in the direction of arrow B by the frictional force with the paper feed roller 6, and is inserted between the paper feed roller 6 and the friction pad 9. It will be done. Here, if the friction coefficient between the paper feed roller 6 and the laminated paper 2 is μm, the friction coefficient between the sheets is μ2, and the friction coefficient between the laminated paper 2 and the friction pad 9 is μm, there is a distance between them of μm>
Because of the relationship μm>μ2, even if two sheets of paper 23, 2□ are fed between the paper feed roller 6 and friction bat 9 in an overlapping manner, the paper 23, 2□ will slip and the lower side Paper 2□ is prevented from moving forward by the friction pad 9, and the upper paper 2. Only the paper is separated and sent out to the delivery side of the paper feed roller 6. The paper 21 separated in this way is sent to the printer from the delivery opening 10 as the paper feed roller 6 rotates, and the paper 21 sent to the printer is printed by a paper feed roller (not shown) on the printer side. The paper will be sent to the department and printed in sequence.

Note that when the paper 21 is fed to the paper feed roller on the printer side, the rotation of the paper feed roller 6 is stopped.

[Problem that the invention seeks to solve]

In the conventional automatic paper feeding device as described above, the paper feeding roller 6 is always connected to the stacked paper 2 on the lifting platform 1 and the friction pant 9.
Because the paper is placed in contact with a predetermined pressure, if the outside air humidity increases and the friction coefficient of the paper changes or the stiffness of the paper becomes weak, it may In the case of a printer that prints at high speed, the next paper 2 □ that is fed into the friction pad 9 with a portion of the paper 21 that is fed into the print section at a relatively high speed by the paper feed roller on the printer side overlaps with the paper 2 is fed into the friction pad 9. The paper passes between the paper feed roller 6 and the friction pad 9 without being blocked by the pad 9. For this reason,
As shown in FIG. 8(b), paper 2. Rear end of paper 2□
There was a problem in that the front edges of the paper overlapped in a continuous state, resulting in double feeding of the paper.

[Purpose of the invention]

The present invention solves the above-mentioned problems, and an object of the present invention is to provide an automatic paper feeding device that can reliably separate and feed sheets and prevent double feeding of sheets.

[Means for solving problems]

The automatic paper feeder of the present invention includes a lifting table that is movably supported in a main body and stacks sheets of paper, and a paper feeder that is rotatably disposed on the paper take-out side of the lifting table so as to come into contact with and separate from the paper. a friction pad that is arranged along a part of the outer periphery of the paper feed roller and separates sheets of paper from the elevator table by rotation of the paper feed roller; a motor that rotationally drives the paper feed roller; an actuator that moves the paper roller toward and away from the paper being fed; and an actuator that moves the paper feed roller away from the paper based on a command signal that detects that a predetermined amount of paper has been fed by the paper feed roller. The actuator is equipped with a control circuit that controls the actuator.

[Action of the invention]

In the present invention, when the paper arrival signal to the paper feed mechanism on the printer side is input to the control circuit, the control circuit gives an operation command to the actuator to separate the paper feed roller from the stacked paper surface. The frictional force between the paper and the second paper is significantly reduced, thereby preventing double feeding of paper into the printer.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 5 show an embodiment of the automatic paper feeder of the present invention, in which FIG. 1 is a longitudinal sectional front view, FIG. 2 is a sectional view taken along the line ■-■ in FIG. FIG. 3 is a partially cutaway side view showing details of the paper roller portion, FIG. 4 is a control block diagram of the paper feed roller operating mechanism, and FIGS. 5 and 6 are operation explanatory diagrams.

In FIGS. 1 and 2, reference numeral 20 denotes a box-shaped paper feeder main body, and at both left and right ends of the main body 20 there are guide plates that also serve as partitions and are passed between the bottom plate 20a and the top plate 2Ob of the main body 20. 21 and 22 are erected. Both ends of the lifting platform 23 are supported by the guide plates 21 and 22 so that they can move up and down horizontally, and on the lifting platform 23 are B4. Paper 2, such as A4 size,
A large number of them are stacked one on top of the other with their lower ends in contact with the guide plate 22.

Ropes 24a, 24b, 24c, and 24d are used to horizontally raise and lower the platform 23, and these ropes 24a to 24 are
One end of d is connected to a square portion of a lifting platform 23 projecting outward from the guide plate 21.22, and the other end is a fixed pulley 25a fixed to the upper end of the guide plate 21.22.
25 b, 25 c.

After being wrapped around the rope 25d, the rope 24 of the guide plate 21
a and 24b are fixed pulleys 26a attached to the bottom plate 20a
, 26b and 27a, 27b into the machine room 28 on the guide plate 22 side, and is wound around drums 29a, 29b provided coaxially within the machine room 28. Further, the ropes 24c and 24d on the guide plate 22 side are connected to the drum 29 via fixed pulleys 30a and 30b attached to the bottom plate 20a.
a.

29b.

The drums 29a, 29b are fixed to a rotating shaft 32 rotatably supported by a bracket 31.31 installed on the bottom plate of the machine room 28, and this rotating shaft 32 is connected to a drive motor 33 installed in the machine room 28. It is connected to the output shaft 33a via a gear train 34.

Reference numeral 35 denotes a paper feed roller located at the upper end of the guide plate 22 and arranged parallel to the paper 2 on the lifting platform 23;
5 is a movable shaft 36 arranged parallel to the paper 2 on the lifting platform 23.
The two ends of the movable shaft 36 are fixed concentrically to the
Support arm 37a.

The support arm 37 is rotatably supported at the tip of the support arm 37b.
a and 37b are rotatably supported by a bracket 38 attached to a support plate 28a in the machine room 28.

One support arm 37a of the movable shaft 36 is formed into an L-shape, and its bent corner is rotatably pivotally connected to a bracket 38, and as shown in FIG. A gear 39 coaxially attached to the support arm 37a and a gear 40 fixed to the movable shaft 36 of the paper feed roller 35 are in mesh with each other via an intermediate gear 41 attached to the horizontal portion of the support arm 37a. A pulse motor 42 for driving a paper feed roller is attached, and intermediate gears 44 and 45 attached to a bracket 38 are meshed in order with a drive gear 43 fixed to the rotating shaft of this pulse motor 42. 45 is meshed with gear 39. Therefore, gears 44°45.39 and 41.40 are
It constitutes a gear train that transmits the rotation of the pulse motor 42 to the paper feed roller 35.

Further, at the tip of the vertical portion 37a1 of the support arm 37a,
A movable rod 46a of an electromagnetic plunger 46 fixed to the bracket 38 is connected, and by energizing the electromagnetic plunger 46, the support arm 37a is rotated to move at least the paper feed roller 35 to the laminated paper 2 on the lifting table 23. It is designed to be separated from the

Reference numeral 47 denotes a friction pad disposed along the outer periphery of the paper feed roller 35 on the opposite side to the lifting table 23, which is molded from cork, rubber, etc. with a coefficient of friction smaller than the surface friction coefficient of the paper feed roller 6, and is made of a material such as cork or rubber that has a coefficient of friction smaller than the surface friction coefficient of the paper feed roller 6. It is fixed to a support member 48 as shown in FIG. In addition, in Figures 1 and 3, 4
9 is a microswitch that detects the presence or absence of the paper 2 on the lifting table 23; 50 is a microswitch that detects the rising end position of the sheet 2 on the lifting table 23; this microswitch 50 controls the drive motor 33; As the paper 2 on the elevating table 23 is fed by the paper feed roller 35, the elevating table 23 is raised, and the laminated paper 2 is held at a level where it contacts the paper feed roller 35 with a predetermined pressure. There is.

Reference numeral 51 denotes a paper feed port formed on the top plate 20b of the paper feeder main body 20, facing between the paper feed roller 35 and the friction pad 47, and a printer 52 is placed on the top plate 20b.
The paper 2 from the paper outlet 51 is sent to a paper feed roller 53 of a printer 52.

In FIG. 4, a control circuit 54 controls an electromagnetic plunger 46 for moving the paper feed roller 35 toward and away from at least the laminated paper 2, and a pulse motor 42 for driving the paper feed roller. , a paper feed command signal from the printer 52 and a detection signal for detecting that the paper 2 has reached the paper feed roller 53 of the printer 52 are input, as well as a drive circuit 56 of the pulse smoke 42 and an electromagnetic plunger. 46 drive circuits 57 are connected to each other.

Next, the operation of this embodiment configured as described above will be explained.

First, with a predetermined amount of paper 2 set on the lifting table 23, when a forward rotation start command is given to the drive motor 33, the drive motor 33 starts, rotates the drums 29a and 29b, and rotates each rope 24a to 24d. By winding up the lifting table 23, the lifting table 23 is raised.

Then, when the uppermost surface of the stacked paper 2 comes into pressure contact with the paper feed roller 35 and the stacked paper 2 turns off the microswitch 50, the drive motor 33 stops and the elevator table 23 also stops.

In this state, when a paper feed command signal is input to the control circuit 54 as the printer 52 starts printing, the control circuit 54
outputs a paper feeding command to the drive circuit 56 to start the pulse motor 42 in normal rotation. When the pulse motor 42 is started to rotate in the normal direction, its rotation is transmitted to the gear 40 through the drive gear 43, intermediate gears 44, 45, gear 39, and intermediate gear 41, as shown in FIG. Rotate the paper roller 35 in the direction of the arrow. Along with this, the uppermost sheet 2 of the stacked sheets 2 pressed against the sheet feed roller 35. is sent out toward the friction pad 47 by the frictional force with the paper feed roller 35, and the paper feed roller 35
and the friction punt 47. At this time,
The next sheet 2□ located directly below the topmost sheet 2° is also sent in the direction of the friction pad 47 due to the frictional force with the sheet 21, but this sheet 2° is blocked by the friction pad 47 as in the conventional case. Paper 2. Only the paper is sent out toward the paper feeding roller 53 of the printer 52 as shown by arrow C through the paper feeding port 51 of the top plate 20b.

Then, as shown in FIG. When the leading end of the printer 52 is completely caught in the paper feed roller 53 of the printer 52, a detection signal indicating this state is output to the control circuit 54, and the control circuit 54 issues a stop command to the drive circuit 56. At the same time, a plunger operation command is sent to the drive circuit 57 to excite the electromagnetic plunger 46, and the movable rod 46a is sucked in the backward direction to move the support arm 37a to its pivot point 39a. By rotating the paper feed roller 35 as a fulcrum from the position indicated by the two-dot chain line to the position indicated by the solid line, the paper feed roller 35 is moved away from the stacked paper 2 on the lifting table 23 by a gap d, as shown by the solid line in FIG.
Separate. As a result, the paper 2I is pulled out from the stacked paper section by the roller 53 and advances along the paper feed roller. At this time, the paper feed roller 35 is rotated, but the paper 2
Since the □ is blocked by the friction pad 47, the sheets 21 and 2 □ are separated, creating a gap d2, and there is almost no frictional force between them. Therefore, the paper 2° remains on the stacked paper to prevent double feeding of the paper.

That is, compared to the friction between the paper 21 and the paper feed roller 35 and between the paper 2 □ and the friction pad 47, the separation of the paper feed roller 35 causes the paper 2. Since the friction between and 2□ is overwhelmingly small, double feeding of paper can be reliably avoided.

In this way, paper 2. is completely fed into the printer 52 side, and accordingly, the next paper feed command is sent from the printer 52 to the control circuit 54, the electromagnetic plunger 46 is demagnetized, and the paper feed roller 35 moves as indicated by the two-dot chain line in FIG. As shown, it is pressed by the stacked paper 2 and returns to the paper feeding position. Then, by starting the pulse motor 42 again, the next sheet 2□ is separated and fed to the printer 52 side.

Thereafter, sheet feeding becomes possible by repeating the above-described operations.

In the automatic paper feeder of this embodiment, when the paper fed by the rotation of the paper feed roller 35 reaches the paper feed roller 53 on the printer side, the electromagnetic plunger 46 is energized to feed the paper. Since the paper roller 35 is spaced apart from the paper, it is possible to ensure that the sheets of paper are separated even when the paper is fed to a high-speed printer such as a laser printer. Double feeding to the printer can be prevented.

Note that the amount of paper fed to the paper feeding roller 53 of the printer 52 is set according to a predetermined number of revolutions or time of the paper feeding roller 35, and thereby the control circuit 54 has the functions of stopping the pulse motor and energizing the plunger. If this is done, the paper detection mechanism on the printer side can be omitted.

Furthermore, in the above embodiment, a case has been described in which the pulse motor 42 is stopped by a command from the control circuit 54, but in this case, the paper feed roller 53 on the print side and the paper feed roller 3
If the peripheral speeds of the rollers 5 and 5 are different, especially if the peripheral speed of the paper feed roller 35 is high, the paper may be gradually fed between the rollers 53 and the printer side, causing the paper to bend or wrinkle. If the peripheral speed on the print side is smaller than the peripheral speed of the paper feed roller 35, it is not necessarily necessary to stop the pulse motor 42.

FIG. 7 shows another embodiment of the automatic paper feeder of the present invention.

In this figure, the same parts as in FIG. 3 are given the same reference numerals, and the explanation thereof will be omitted, and different parts will be mainly described.

That is, as is clear from FIG. 7, the paper feed roller 35 is
A support arm 58 is rotatably connected via a shaft 36 to one end of a support arm 58 that moves in a direction toward and away from the laminated paper 2 and the friction pad 47, and a paper feed roller 35 is mounted at the other end of the support arm 58 in a direction toward and away from the stacked paper 2 and friction pad 47. The electromagnetic plunger 46 is connected to the electromagnetic plunger 46 for operation. In addition, between the pulse motor 42 and the paper feed roller shaft 36, a timing block 1J59 attached to the rotating shaft of the pulse motor 42, a timing block IJ60 attached to the paper feed roller axis 36, and a timing pulley 59°60 of these are wound. They are connected by a timing belt 61.

In the embodiment of FIG. 7 constructed in this way, the same effects as in the above embodiment can be obtained.

Note that the means for operating the paper feed roller toward and away from the paper feed roller is not limited to the electromagnetic plunger.

〔Effect of the invention〕

As described above, according to the present invention, when the paper on the elevating table fed by the paper feed roller is sent out a predetermined amount to the print side, the actuator is operated to separate the paper feed roller from the paper, and the paper feed roller Since almost no frictional force is generated between the paper and the friction pad, paper sheets can be separated reliably and double feeding of paper can be prevented, making it suitable for sheet feeding into high-speed printers such as laser printers. There is a certain effect.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view showing an example of an automatic paper feeder according to the present invention. FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1. FIG. 3 is a side view showing details of the paper feed roller drive mechanism in this embodiment. FIG. 4 is a block diagram for controlling the pulse motor for driving the paper feed roller and the paper feed roller contact/separation means in this embodiment. 5 and 6 are side views for explaining the operation of the paper feed roller section. FIG. 7 is a side view of a paper feed roller section showing another embodiment of the present invention. FIGS. 8(a) and 8(b) are explanatory diagrams showing a conventional paper feeding device. [Explanation of symbols of main parts] 2...Paper 20...Paper feeder body 23...Elevating table 33...Elevating table drive motor 35...Paper feeding roller 36...Movable shaft 37a , 37b, 5B - Support arm 46... Electromagnetic plunger 47... Friction pad 54... Control circuit 56.57... Drive circuit. (a) Figure 8

Claims (1)

[Claims] An elevating table that is movably supported within the main body and stacks sheets of paper; a paper feed roller that is rotatably disposed on the paper take-out side of the elevating table so as to come into contact with and separate from the paper; and one of the paper feed rollers. A friction pad is arranged along the outer periphery of the paper feed roller and separates sheets of paper from the elevator table by rotation of the paper feed roller, a motor that rotationally drives the paper feed roller, and a friction pad that separates the paper feed roller from the feed paper. an actuator that is brought into contact with the paper; and a control circuit that controls the actuator to move the paper feed roller away from the paper based on a command signal that detects that a predetermined amount of paper has been fed by the paper feed roller. Automatic paper feeder.