JPH01118466A - Automatic sheet feeder - Google Patents

Abstract

PURPOSE:To facilitate the supply and replacement of a sheet by providing a control circuit for so controlling the reverse rotation of a sheet feed roller driving motor as to return the sheet engaged between a sheet feed roller and a friction pad onto an elevation base. CONSTITUTION:A control circuit 54 inputs ON/OFF signal of a microswitch 50 and a signal of a manual switch 55. When a sheet on an elevation base 23 is supplied or replaced, a sheet 22 being fed by a sheet feed roller 35 is fed to a printer 52, the switch 5 is then pushed. Then, the circuit 54 applies a reverse rotation start command to a driver circuit 57 to reversely rotate a pulse motor 42, thereby rotate the roller 35. Thus, a sheet 23 to be fed next and engaged between friction pads 47 is returned to laminated sheets 2 of the base 23. When it is controlled to be reversely rotated at predetermined number of revolutions, the motor is stopped, a drive motor 33 is reversely rotated, thereby moving down the base 23.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an automatic paper feeding device applied to laser printers and other page printers, and in particular, the present invention relates to an automatic paper feeding device that is applied to laser printers and other page printers. 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. 9A to 9C are side views of main parts of a conventional automatic paper feeder.

In the figure, ■ is an elevating table on which a large number of sheets 2 of various sizes such as A4 and 84 are stacked, and 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 arrow A in FIG. 9(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, and the paper feed roller 6 is inserted between the friction pads 9. . Here, if the friction coefficient between the paper feed roller 6 and the paper 2 is μ8, the friction coefficient between the sheets is μ2, and the friction coefficient between the paper 2 and the friction pad 9 is μ3, then the distance between them is μm〉μ3〉μ2
Because of this relationship, even if two sheets of paper 26, 2□ are fed between the paper feed roller 6 and the friction bat, the paper 28, 2□ will slip, and the lower paper 2□ will be The front side is blocked by the friction pad 9, and only the upper sheet 21 is separated and sent out to the sending side of the paper feed roller 6.

Paper separated in this way 2. is sent to the printer from the delivery opening 10 as the paper feed roller 6 rotates, and the paper 2I sent to the printer is sent to the printing section by a paper feed roller (not shown) on the printer side, where it is sequentially printed. It turns out.

Note that when the paper 2I is fed to the paper feed roller on the printer side, the drive shaft 7 stops rotating, but since the paper 2I is pulled out by the paper feed roller on the print side, the one-way clutch 8 causes the paper feed roller to disengage and rotate. do.

[Problem that the invention seeks to solve]

In the conventional automatic paper feeder as described above, when the drive shaft 7 rotates in the direction of arrow A, the one-way clutch 8 connects the paper feed roller 6 and the drive shaft 7, and controls the rotation of the drive shaft 7 to feed the paper. The information is transmitted to the roller 6, and the feed roller 6 itself is moved in the direction of the arrow A with respect to the drive shaft 7.
When rotating in the direction, the paper can be rotated freely so that the paper can be easily pulled out by the paper feed roller on the printer side, and in the paper feeding position, the stacked paper 2 on the lifting platform 1 is rotated freely by the paper feed roller. 6, so when the paper feed roller 6 rotates in the direction of arrow A in FIG. 9(a),
When the uppermost paper 2I in contact with the paper feed roller 6 is fed to the friction pad 9 side, the paper 2I in contact with the paper 2°
□ is also caused by the frictional force between sheets of paper 2. The paper 2 is dragged to the side of the friction pad 9, separated by the friction pad 9, and sent to the printer side.
The leading end of the paper 2 □ following paper 1 is always held between the paper feed roller 6 and the friction pad 9 as shown in FIG. 9(b).

In this case, the stacked paper 2 on the lifting table 1 and the paper feed roller 6 are in the state shown in FIG. 9(a), and the next paper 22 is also the same as the first paper 2. There is no problem when the paper is sequentially fed to the printer after printing, but when the lifting platform 1 is lowered as shown in Figure 9 etc. to replenish paper during printing or to replace paper, etc. , at least the next fed paper 2
The tip of the paper is held between the paper feed roller 6 and the friction pad 9, and it hangs down from the paper feed roller 6, interfering with replenishing paper to the lifting platform 1 or replacing the paper, making it difficult to perform the work. In addition to causing trouble, if the paper caught between the paper feed roller 6 and the friction pad 9 is forcibly pulled out by hand as shown in Figure 9(C), the paper may be torn or wrinkled, making it unusable. There was a problem with paper being wasted.

[Purpose of the invention]

The present invention was made to solve the above-mentioned problems, and automatically returns the paper caught between the paper feed roller and the friction pad onto the elevating platform, eliminating wasted paper and improving paper replenishment. The present invention also aims to provide an automatic paper feeder that facilitates paper exchange.

[Means for solving problems]

The automatic paper feeder of the present invention includes an elevating table that is movably supported within the main body and stacks sheets of paper, and a paper feed roller that is rotatably arranged to press the paper against the paper take-out side of the elevating table. ,
A friction pad is arranged along a part of the outer periphery of the paper feed roller and separates sheets of paper from the elevator platform by rotation of the paper feed roller, a motor drives the paper feed roller in forward and reverse directions, and a motor drives the paper feed roller in forward and reverse directions. and a control circuit for controlling the paper feed roller drive motor in reverse so as to return the paper held between the friction pads onto the elevating table.

[Action of the invention]

In the present invention, when a command to lower the elevator platform is input to the control circuit, the control circuit sends a reverse rotation command to the paper feed roller drive motor, whereby the paper feed roller is rotated in the opposite direction when paper is fed. Then, the paper that was held between the paper feed roller and the friction pad is automatically returned to the elevator table.

Therefore, in the present invention, paper is not wasted, and paper replenishment and paper replacement are facilitated.

[Embodiments of the invention]

Embodiments of the present invention will be described below based on the drawings.

1 to 7 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 feed roller portion, Fig. 4 is a control block diagram of the paper feed roller and elevator drive motor, and Figs. 5 to 7 are operation explanatory diagrams. .

In FIGS. 1 and 2, reference numeral 20 denotes a box-shaped paper feeder main body, and inside this main body 20, on both left and right ends, 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 lifting platform 23, and each of these ropes 24a to 2
One end of 4d is connected to the square part of the lifting platform 23 that projects outward from the guide plate 21, 22, and the other end is
Fixed pulleys 25a, 2 fixed to the upper end of the guide plate 21.22
5b, 25c.

25d, the rope 24 on the guide plate 21 side
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 table 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 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 the bracket 3, and as shown in FIG. A gear 39 coaxially attached to the mounting portion 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 the paper feed roller is attached to the .
A drive gear 43 fixed to the rotating shaft of this pulse motor 42
, there is an intermediate gear 44 attached to the bracket 38. ．． 4
5 are meshed in order, and the intermediate gear 45 is meshed with the gear 39. Therefore, gears 44, 45, 39. and 41.4
0 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 37a+ 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 and the paper feed roller 35 is separated from the stacked paper 2 on the lifting table 23. It is supposed to be done.

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 held at a level where the stacked paper 2 contacts the paper feed roller 35 with a predetermined pressure. .

Reference numeral 51 denotes a paper delivery 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 2Ob.
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 the drive motor 33 and the pulse motor 42, and this control circuit 54 includes an on/off signal for a microswitch 50 that limits the level of elevation of the platform 23, and an on/off signal for operating the platform. The signals from the manual switch 55 are respectively inputted thereto, and the drive circuit 56 of the drive motor 33 and the drive circuit 57 of the pulse motor 42 are respectively connected.

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

First, when a predetermined amount of paper 2 is set on the lifting platform 23 and the manual switch 55 is turned on, the ON signal is taken into the control circuit 54, thereby sending a lifting platform raising command to the drive circuit 56. . Upon receiving this command, the drive circuit 56 drives the drive motor 33 in forward rotation to rotate the drum 29a.

29b is rotated to wind up each of the ropes 24a to 24d, thereby raising the lifting platform 23. And laminated paper 2
When the top surface of the stacked paper 2 comes into pressure contact with the paper feed roller 35 and the microswitch 50 is turned off, the control circuit 54
sends a stop command to the drive circuit 56 to stop the drive motor 3.
3 and the lifting platform 23 is stopped.

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 feed command to the drive circuit 57 and the pulse motor 4
2 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 being pressed against the sheet feed roller 35
1 is sent out toward the friction pad 47 by the frictional force with the paper feed roller 35, and is inserted between the paper feed roller 35 and the friction pads 1-4. At this time, the next paper 2□ located directly below the top paper 21 is also paper 2. The paper 2□ is sent out in the direction of the friction pad 47 due to the frictional force between the sheet 2 and the paper 2, but this paper 2□ is blocked by the friction pad 47 as in the past, and only the paper 21 passes through the paper delivery port 51 of the top plate 20b as shown by arrow C. The paper is sent out toward the paper feed roller 53 of the printer 52. Then, as shown in FIG. 6, when the leading edge of the paper 2I is completely caught in the paper feed row 53 of the printer 520, the pulse motor 42 stops and the electromagnetic plunger 46 is energized, and the movable rod By suctioning the support arm 37a in the backward direction, the support arm 37a is rotated from the position indicated by the two-dot chain line to the position indicated by the solid line, using the pivot portion 39a as a fulcrum, thereby moving the paper feed roller 35 as shown by the solid line in FIG. In this way, the paper 2I is separated from the stacked paper 2 on the lifting table 23, and the paper 2 is completely separated, thereby reducing the feeding force of the paper 2I applied to the paper feed roller 53 on the printer side, and at the same time, the pulse motor By turning off the power to the paper 2.42 and setting the pulse motor 42 in a free state, the paper 2. is transferred to the paper feed roller 35 by the paper feed roller 53.
When the paper 2I is pulled out from the paper feed roller 35, the paper 2I is easily rotated and the pulling force of the paper 2I is reduced.The reason for doing this is that the paper feed roller 35 is fixed to the movable shaft 36, This is because the structure does not allow free rotation in the paper withdrawal direction via the one-way clutch.

When the paper 21 is completely fed into the printer 52 in this way and the next paper feeding command is sent from the printer 52 to the paper feeding device, the electromagnetic plunger 46 is demagnetized and the paper feeding roller 35 is As shown by the two-dot chain line in FIG. 6, 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 22 is separated and fed to the printer 52 side.

Next, 3Ae will be explained regarding the case where the paper on the elevating table 23 is replenished or the paper on the elevating table 23 is replaced with another sheet.

In this case, first, after the paper 2° being fed by the paper feed roller 35 is sent to the printer 52 side as shown in FIG. 7(a), that is, in the state shown in FIG. 7(b),
Operate the manual switch 55. At this time, a micro switch 5 detects the rising edge level of the stacked paper 2.
0 is off, when the manual switch 55 is pressed, the control circuit 54 that receives this on signal gives a reverse start command to the drive circuit 57, which causes the redrive circuit 57 to start the pulse motor 42. Start in reverse. For this purpose, the paper feed roller 35 is connected via a gear train.
is rotated in the direction of the arrow shown in FIG. 7(b), and as shown in FIG.
As shown in b), the friction pad 4 is attached to the paper feed roller 35.
As the paper feed roller 35 rotates in the direction of the arrow, the paper 23 to be fed next, which has been held between
), the paper is returned onto the stacked paper 2 on the lifting table 23.

When the paper feed roller 35 is reversely controlled by the control circuit 54 for a predetermined number of rotations (or time) sufficient to completely return the paper 23 onto the stacked paper 2, the reverse rotation command from the control circuit 54 is stopped, and the pulse Stop the motor. Subsequently, a reverse rotation command is sent to the drive circuit 56, and the drive motor 33
The lifting table 23 is lowered by starting the drums 29a and 29b in the rope rewinding direction by starting them in reverse.

Further, when the lifting platform 23 reaches the lowering end, a limit switch (not shown) or the like is activated to stop the drive motor 33.

In the automatic paper feeder of this embodiment, when the lifting table 23 is lowered by operating the manual switch 55, the paper feed roller 35 rotates in the opposite direction, causing a gap between the paper feed roller 35 and the friction pad 47. Since the paper held in the mouth is automatically returned to the lifting platform 23, paper replacement and paper replenishment are facilitated, and paper waste can be eliminated.

In the above embodiment, a case has been described in which the paper feed roller 35 is controlled in reverse by a switch signal when the manual switch 55 is turned on, but the present invention is not limited to this, for example,
On the printer 52 side, a print stop signal indicating that the required number of sheets has been printed is input into the control circuit 54, which issues a reverse drive command to the pulse motor 42, so that when printing is stopped, the paper stack is always fed. The paper held between the paper roller 35 and the friction pad 47 may be returned.

Further, in the above embodiment, paper 2. is caught by the print side paper feed roller 53, the pulse motor 42 stops and at the same time the plunger 46 is energized and the paper feed roller 3
5 is separated from the laminated paper, but this is a means to prevent paper from being fed multiple times to the printer, and does not interfere with the paper return function, which is the object of the present invention.

FIG. 8 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. 8, the paper feed roller 35 is
This is rotatably connected via a shaft 36 to one end of a support arm 58 that moves in the direction toward and away from the laminated paper 2 and the friction pad 47, and the paper feed roller 35 is connected to the other end of the support arm 58 in the direction toward and away from the stacked paper 2 and the friction pad 47. An electromagnetic plunger 46 that operates to
Connect to.

Additionally, a timing pulley 5 attached to the rotating shaft of the pulse motor 42 is connected between the pulse motor 42 and the paper feed roller shaft 36.
9, and a timing boot I attached to the paper feed roller shaft 36.
J60 and these timing boots U59 and 60 are connected by a timing belt 61 wrapped around them.

In the embodiment of FIG. 8 constructed in this manner, the same effects as in the above embodiment can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, when the control circuit receives a command to replace paper, replenish paper, or finish printing the required number of sheets in the printer, the paper feed roller is rotated at a predetermined number of rotations or reversely for a predetermined period of time. Since the paper that is caught between the paper feed roller and the friction pad is automatically returned to the elevating table, there is no wastage of paper, and paper replacement and paper replenishment are facilitated. It has the effect of

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional front view showing an example of an automatic paper feeder of 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 motor for driving the lifting platform in this embodiment. 5 and 6 are side views of the paper feed roller section for explaining the operation. FIGS. 7(a) to 7(C) are diagrams for explaining the paper return operation in this embodiment. FIG. 8 is a side view of a paper feed roller section showing another embodiment of the present invention. FIGS. 9(a) to 9(C) 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 55...manual switch 56.57...drive circuit. Patent applicant: Daiwa Seiko Co., Ltd. - Chang

Claims (2)

[Claims] (1) A lift table that is supported in the main body so that it can be raised and lowered and that stacks sheets of paper, a paper feed roller that is rotatably placed in pressure contact with the paper on the paper take-out side of the lift table, and a A friction pad is arranged partially along the outer periphery and separates sheets of paper from the elevator table by the rotation of the paper feed roller, a motor drives the paper feed roller in forward and reverse directions, and there is a friction pad between the paper feed roller and the friction pad. An automatic paper feeder comprising: a control circuit that controls the paper feed roller drive motor in reverse so as to return the paper held in its mouth onto the elevating platform. (2) The control circuit is configured to reversely control the paper feed roller drive motor based on a lowering operation command signal of the elevator platform or a print stop command signal of the printer. Automatic paper feeder as described.