JPH02152824A - Automatic paper feeding device - Google Patents

Abstract

PURPOSE:To enable to hold the gap between laminated sheets and a paper feed roller constant and at a minimum by providing such a constitution as retarding a pressure plate against a pressing means by a rack opinion mechanism, making a holding mechanism hold this retarded position, and separating the laminated sheets on the pressure plate from a paper feed roller. CONSTITUTION:When a paper feed motor is rotated, this rotation is transmitted to paper feed rollers 24a, 24b through a rotation transmitting mechanism to rotate the paper feed rollers 24a, 24b, whereby sheets 10A on pressure plates 22a, 22b are sent one by one to the printer unit side. When the sheets are caught by the paper feed rollers on the printer unit, the paper feed motor is reversely rotated in a determined amount, this rotation is transmitted to a movable rack plate 45 of a rack mechanism through the rotation transmitting mechanism, and the pressure plates 22a, 22b are retarded against a pressing means 23 by the sliding motion of the movable rack plate 45 and a pinion 27b rolled on a fixed rack 47 with being rotated by said motion, whereby the laminated sheets 10A can be held away from the paper feed rollers.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a sheet-fed automatic paper feeding device that separates stacked sheets of paper one by one and sends them to a printer, and particularly relates to a pressure plate in which stacked sheets of paper are set. This invention relates to an automatic paper feeder that can be retracted.

[Conventional technology]

Conventionally, this type of automatic paper feeder uses a sensor to detect the amount of paper stacked in a paper feed stacker, and uses this detection signal to control an electric actuator to move the pressure plate backward according to the amount of paper stacked. , a type in which the stacked paper is separated from the paper feed roller, or a type in which the pressure plate is moved backward to a certain position by an electromagnetic plunger, etc., regardless of the amount of paper stored in the paper feed stacker. [Problems to be Solved] By the way, in the former conventional method described above, a sensor and an electric actuator for operating the pressure plate are required, and the amount of retraction of the pressure plate is determined according to the amount of paper, and the electric actuator is required to operate the pressure plate. This necessitates an arithmetic control circuit for controlling the paper feed unit, which makes the retraction drive mechanism expensive, and requires a separate electric actuator, which increases the weight of the paper feed unit.

In addition, in the latter method, the pressure plate 1- is retracted to a fixed position regardless of the amount of paper stored in the paper feed stacker, so when the amount of paper is small, the stacked paper set on the pressure plate The gap between the top surface of the paper and the paper feed roller increases, and as a result, the pressure plate is moved back more than necessary, resulting in a large time loss.As the pressure plate advances and retreats, the paper becomes stuck in the paper feed stacker. The paper moves and becomes uneven,
In addition to causing skew and uneven printing positions, there have been problems in that the gap between the paper and the paper feed roller becomes large, causing the paper to buckle and prevent normal paper feeding.

The present invention solves the above-mentioned problems and makes it possible to maintain a constant gap between the stacked paper and the paper feed roller regardless of the amount of paper stored in the stacker and without using a separate drive source. An object of the present invention is to provide an automatic paper feeder capable of retracting a pressure plate.

[Means for Solving the Problems] The automatic paper feeding device of the present invention includes a pressure plate that is supported by a stacker frame main body so as to be swingable in the front and rear directions and presses the stacked paper, and a pressure plate that is located in front of the pressure plate and that A paper feed roller rotatably supported by a frame body, a pressing means for pressing the stacked paper against the paper feed roller via the pressure plate, a paper feed motor attached to the frame body and capable of forward and reverse rotation; a rotation transmission mechanism that transmits the rotation of the paper feed motor to the paper feed roller when the paper feed motor rotates in the forward direction; a rack mechanism for advancing and retracting the pressure plate having a rank plate that moves in accordance with the moving direction of the pressure plate; and a rack mechanism for advancing and retracting the pressure plate; The apparatus includes a rotation transmission mechanism that transmits rotation to a movable rack of the rack mechanism to cause the pressure plate to move backward against the pressing means, and a holding mechanism that holds the pressure plate 1 in the retreated position. be.

[For production]

In the present invention, when the paper feed motor rotates forward, this rotation is transmitted to the paper feed roller via the rotation transmission mechanism, and by rotating the paper feed roller, one sheet of paper on the pressure plate is transferred to the printer unit side. send out. Then, when the paper is caught in the paper feed roller of the printer unit,
The paper feed motor reversely rotates by a predetermined amount, and the rotation is transmitted to the movable rack of the rack mechanism via the rotation transmission mechanism, and the movable rack slides and thereby rolls on the fixed rack while being rotated. The pressure plate is moved backward by the pinion against the pressing means, and the stacked paper on the pressure plate is separated from the paper feed roller, and the backward position of the pressure plate is held by the holding mechanism.

When the pressure plate is retracted, - as the toothed gear is rotated 1/2 from the reference position, - the angle from the start point of engagement between the toothed gear and the movable rack plate to the end point of the 1/2 rotation is approximately constant. Therefore, when the movable rack plate is moved by an amount corresponding to this angle, the pinion will also roll in the same direction by a predetermined distance.

Therefore, in the present invention, even if the amount of paper stored in the paper feed stacker changes, the gap formed between the stacked paper and the paper feed roller can be kept constant by the backward movement of the pressure plate.

〔Example〕

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

FIG. 1 is a partially cutaway front view showing an example of an automatic paper feeder according to the present invention, and FIG. 2 is a partially cutaway front view of a flat printer equipped with the automatic paper feeder according to the present embodiment. FIG.

In the figure, 1 is a printer unit, and 2 is an automatic paper feed unit that is removably set on the printer unit 1.

As shown in FIG. 2, the printer unit 1 includes a printer main body 3 and a paper discharge stacker 4 that is removably set on the printer main body 3.

The printer main body 3 has a paper guide plate 5 arranged horizontally in the direction from the automatic paper feed unit 2 to the paper discharge stacker 4 at its upper part. A platen 6 is disposed perpendicular to the longitudinal direction of the paper guide plate 5, and a print head 7 is disposed above the platen 6. Also, platen 6
A pair of paper feed rollers 8a and 8b that feed the paper 10A fed from the automatic paper feed unit 2 toward the print head 7 are placed on the paper introduction end side of the paper guide plate 5 located at the front stage of the Further, on the terminal end side of the paper guide plate 5 located after the platen 6, a pair of paper feed rollers 9a and 9b for feeding the printed paper to the paper ejection stacker 4 are arranged vertically in contact with each other. has been done. The paper feed rollers 8a, 8b and 9a, 9 at the front and rear stages
b is rotationally driven by a motor (not shown).

The paper discharge stacker 4 includes a paper guide 11 that guides the printed paper 10B sent by the paper feed rollers 9a and 9b to the storage section 4a of the paper discharge stacker 4, and one end of this paper guide 11 is connected to the stacker frame. An operating lever 12 rotatably attached to the body 4b and protruding outside the stacker frame 4b.
This allows the paper guide 11 to be switched between the position shown by the solid line and the position shown by the two-dot chain line in FIG.
When is in the position shown by the solid line, the printed paper 10B is guided to the paper ejection stun force 4, and when it is in the position shown by the two-dot chain line, it is guided through the front paper ejection path 13 formed in the printer main body 3 to the print main body. 3 It is designed to be discharged outside.

Reference numeral 14 denotes a paper ejection roller rotatably provided on the stacker frame 4b in close proximity to the pivot base of the paper guide 11.
By transmitting the rotation of the paper feed roller 9a to the paper discharge roller 14, the printed paper 10B guided through the paper guide 11 is transferred to the storage section 4a. It is designed to be sent to

Next, the automatic paper feeding unit 2 will be described.

As shown in FIGS. 1 and 2, the automatic paper feed unit 2 accommodates a frame body 17 that is removably inserted onto the printer unit 1 and unprinted sheets 10A stacked in an inclined manner. A paper feed stacker 18 is provided.

The paper feed stacker 18 has left and right side plates 17a and 17b that constitute the frame body 17, as shown in FIGS. 1 and 10.
A guide rod 19 and a guide bar 20 are horizontally fixed in between.
It has its own support plates 21a, 21b which are movably supported along the longitudinal direction thereof, and pressure plates 22a, 22b which are attached to the upper ends of each of these support plates 21a, 21b so as to be movable in the front and back direction. pressure plate 2
2a and 22b are pressure springs 23 interposed between their swinging lower ends and the respective support plates 21a and 21b facing thereto.
is constantly urged forward by the pressure plate t-2
The sheets 10B stacked and stored in the pressure plates 2a and 22b are pressed against paper feed rollers 24a and 24b, which will be described later, and the swinging ends of the pressure plates 22a and 22b are provided with holes that pass horizontally in the left-right direction. A pressure plate shaft 25 is attached, and both ends thereof are attached to the left and right side plates 1.
The guide holes 26a and 26b (see FIGS. 1 and 4) formed in the guide holes 7a and 17b project out of the side plate, and pinions 27a and 27b (see FIGS. 1 and 4) are attached to the projecting ends. Fixed.

The paper feed rollers 24a, 24b have left and right side plates 17a,
It is attached to a roller shaft 28 (see FIG. 1) which is rotatably suspended horizontally between the roller shafts 17b and 17b so as to be movable only in the axial direction. A gear 29e constituting the gear train is attached via a one-way hair ring 30 that transmits rotation in only one direction.

In Figures 1 to 3, 31 is pressure play)2
This paper feed motor 31 is fixed to a support plate 33 attached parallel to the right side plate 17a by a plurality of supports 32, and protrudes inside the support plate 33. A drive gear 34 is fixed to the rotating shaft of the paper feed motor 31. Further, a paper feed roller 24 is provided on the inner surface of the support plate 33 as shown in FIGS. 4 and 5.
a.

Gears 29a to 2 forming a gear train for transmitting rotation to 24b
9d is rotatably attached to the shaft, and gear 2 of this gear train
9a is engaged with the drive gear 34, and the gear 29d is connected to the one-way bearing 3 on the paper feed roller shaft 28 as shown in FIG.
It is meshed with a gear 29e attached via 0.

Further, the gear train for reversing the pressure plates 22a and 22b consists of gears 35a to 35d, of which the gear 35a meshing with the drive gear 34 and the gear 35b coaxial therewith are rotatably supported on the support plate 33. The gear 35c that meshes with the gear 35b is rotatably supported on the right side plate 17b, and the gear 35d that meshes with the gear 35c is supported on a shaft supported on the right side plate 17b as shown in FIG. It is fixed to the outer ring of a one-way bearing 37 fitted in the section 36. Further, a shaft 38 is fitted into the inner ring of the one-way bearing 37, one end of which is supported by the shaft bearing part 36, and the other end has a shaft 38 extending 180 mm in the circumferential direction.
A mold wheel 39 having notches 39a and 39b with a phase difference of 100 degrees is fixed to the boss portion of the mold wheel 39.
0 is formed. A tension spring 41 is placed between the outer peripheral edge of the model wheel 39 and the support plate 33 in order to return the circumferential position of the gear gear 40 to the reference point, and furthermore, on the right side plate 17b, A pawl is provided that prevents the mold wheel 39 from reversing by engaging with the notch 39a or 39b. That is, a pawl 42 that holds the pressure plates 22a, 22b in the retracted position is rotatably attached by a stud 43, and this pawl 42 is urged by a torsion spring 44 in a direction to constantly engage with the notch 39a or 39b. There is.

In FIGS. 1, 3 to 5, and 8, the movable rack plate 45 for retracting the pressure plate is located on the right side plate 1.
7b is disposed on the surface facing the support plate 33 above the elongated hole 26b for guiding the pressure plate shaft, and is slid in the longitudinal direction of the elongated hole 26b by a guide protrusion 46 protruding from the right side plate 17'b. It is movably supported and has a sliding groove 4.
By applying viscous oil such as relatively high viscosity grease to 5A, an oil damper function is created in the sliding motion of the movable rack plate 45. In addition, a sliding groove 45A formed in the longitudinal direction of the movable rack plate 45 is provided on the right side plate 17b.
The elongated hole 26b is slidably supported in the longitudinal direction by engaging with a guide protrusion 46 protruding from the movable rack plate 45, and rack teeth 45a formed on the upper edge of the movable rack plate 45 It is designed to intermittently mesh with a toothed gear 40 formed on the boss portion, and rack teeth 45b formed on the lower edge are meshed with a pinion 27b fixed to the pressure plate shaft 25. Further, a fixed rack 47 located below the elongated portion 26b and provided along the elongated hole 26b in the right side plate 17b is engaged with the pinion 27b from below. Furthermore, a fixed rack 48 is located on the left side plate 17a below the elongated hole 26a for guiding the pressure plate shaft.
is provided along the elongated hole 26a, and this fixed rack 4
8 is fixed to the pressure plate shaft 25.
7a are engaged.

In FIG. 2, 49 is the front paper feed roller 8a, 8b.
A paper sensor 50 arranged close to
51 is a paper guide path that guides the paper to the space between b and 51 is a release lever of the pressure plate.

Next, the operation of this embodiment configured as described above will be explained in the 10th section.
This will be explained with reference to FIGS. 16 to 16.

First, before paper feeding to the printer unit 1 is started, the pressure plates 22a and 22b are pressed against the paper feed rollers 24a and 24 by the pressure spring 23, as shown in FIG.
It is pressed in the b direction, thereby causing the rib reflexion plate 22
The entire stack of paper 10A set on sheets a and 22b is pressed into contact with paper feed rollers 24a and 24b.

At this time, the pressure plate shaft 25 and the binions 27a and 27b, which are integrated with the pressure plates 22a and 22b,
The movable rack plate 45 that meshes with the pinion 27b is held at the forward end position as shown in FIG. 8 (this forward end position varies depending on the stacked thickness of the sheets 10A set on the pressure plates 22a and 22b), And nail type 3
9 and -toothed gear 4o are held at the reference position shown in FIG.
is engaged with the first notch 39a.

In this state, the control circuit of the printer unit 1 (
When a paper feeding command is given to the paper feeding motor 31 from a motor (not shown), and the paper feeding motor 31 is started in the paper feeding direction (forward rotation direction), the drive gear 34 is rotated in the direction of arrow A in FIG. Accordingly, the final stage gear 29e of the paper feed gear train that meshes with the drive gear 34 rotates in the direction of arrow B in FIG. The stage gear 35d rotates in the direction of arrow C in FIG.

When gear 29e of the paper feeding gear train rotates in the direction of arrow B,
One-way bearing 30 connects paper feed roller shaft 28 and gear 2
9e, the paper feed rollers 24a and 24b rotate in the direction of arrow B in FIG.
The paper is sent out in the direction of the paper guide path 50 as shown in FIG.

Furthermore, when the gear 35d of the pressure plate retraction gear train is rotated in the direction of arrow C, the one-way bearing 37 that supports it becomes free with respect to the shaft 38, and the pawl 42 is locked in the notch 39a of the pawl type 39. Therefore, the rotation of the gear 35d is not transmitted to the pawl mold 39 and is held in a stopped state.

In the above-mentioned state, the unprinted paper 10A is sent out to the printer unit 1 side as the paper feed rollers 24a and 24b rotate, and after the leading end of the paper is detected by the paper sensor 49, the unprinted paper 10A is fed out for a predetermined period of time, for example, 5 lines. When the corresponding paper feed is performed, paper 10A.

The leading end of the paper 10A hits between the stationary paper feed rollers 8a and 8b, and the paper 10A is accordingly curved as shown by the two-dot chain line in FIG. As a result, the leading edge of the paper 10A is brought into contact with the paper feed rollers 8a and 8b in parallel,
To prevent paper from being caught diagonally between paper feed rollers 8a and Bb, that is, from being skewed.

After the paper sensor 49 operates and the paper feed operation corresponding to five lines is completed, the paper feed motor 31 stops, the paper feed roller drive motor (not shown) of the printer unit l starts, and the paper Feed rollers 8a, 8b (and 9a, 9b)
Rotate. As a result, the paper feed rollers 8a and 8b grip the paper 10A1 that is in contact with them, for example, 2
When the paper is fed by the number of lines, the paper feed rollers 8a, 8
b (and 9a, 9b) stops.

When the paper feed roller drive motor stops, the paper feed motor 3
1 is given a reverse rotation start command, and the paper feed motor 31 is started to rotate in the direction opposite to arrow A in FIG. Then, the final stage gear 29e of the paper feed side gear train that meshes with the drive gear 34 is rotated in the direction opposite to arrow B in FIG. 4, but since the one-way bearing 30 becomes free with respect to the roller shaft 28,
The roller shaft 28 including the paper feed rollers 24a and 24b does not rotate.

On the other hand, the rotation of the drive gear 34 in the direction opposite to the arrow A is gear train 3.
5a to 35d, the final stage gear 35d is rotated in the direction opposite to the arrow C in FIG. The included pawl mold 39 is rotated in the direction opposite to arrow C from the M wheel position shown in FIG. Here, paper feed motor 3
1 is designed to stop after the claw mold 39 is rotated approximately 1/2 turn.

Therefore, as the claw type 39b including the toothed gear 40 is rotated in the direction opposite to the arrow C from the reference position shown in FIG. When the - tooth gear 40 is engaged with the rack teeth 45a and further rotates in the direction of the arrow, the movable rack plate 45 slides in the direction of the arrow in FIG. When the movable rack plate 45 moves in the direction indicated by the arrow, the pinions 27a meshing with the rack teeth 45b rotate in the direction indicated by the arrow E in FIG.
As the pinion 27a rotates, it moves on the fixed rack 47 in the same direction as the moving direction of the movable rack plate 45. At this time, the rotation of the binion 2'7b is transmitted to the opposite binion 27a via the pressure plate 25, so that the binion 27a also engages with the fixed rack 48.
It will roll on the top in the same direction as the pinion 27b.

Then, when the - tooth gear 40 is rotated by a preset angle θ from the meshing start position with the rack teeth 45a as shown in FIG.
As the pressure plate shaft 25 moves from the position indicated by the two-dot chain line to the position indicated by the solid line in the figure, the pressure plate shaft 25 retreats by a certain amount. When the pressure plate shaft 25 moves backward, the integrated pressure plates 22a and 22b also move backward by L against the pressure spring 23, and as shown in FIG. A gap G is created between the top layer sheets. As a result, the paper feed roller 8a,
Paper 10A held in paper 8b.

The pressing force of the pressing spring 23 is released, and the paper feeding load on the paper feeding rollers 8a and 8b is reduced.

In addition, the claw mold 39 is rotated approximately 1/2 due to the reverse rotation of the paper feed motor 31.
When it is stopped after two rotations, the one-tooth gear 40 is engaged with the rack teeth 45a as shown in FIG. 13, and the pawl 42 is engaged with the notch 39b of the pawl mold 39 as shown in FIG. Since the pressure plates 22a and 22b are stopped,
are locked in the backward position, and the pressure plate 22a,
22b is pressed against the paper feed roller 24a by the spring force of the pressure spring 23.
.

This prevents it from being pushed back to the 24b side.

Due to the reverse rotation of the paper feed motor 31, the pressure plate 22a
, 22b is completed, the printer unit 1
starts the actual printing operation, and the printer motor (not shown)
The paper feed rollers 8a, 8b and 9a, 9b are rotated intermittently to transport the paper, and the print head 7 is operated to perform printing. Then, the end of the paper lOA+ fed into the printer unit 1 is detected by the paper sensor 4.
After the paper sensor 49 detects that the paper has passed 9,
When printing on the paper 10A is completed, a paper ejection command is applied to the printer motor, and in particular, the subsequent paper feed rollers 9a and 9b and the paper ejection roller 14 are continuously rotated to transfer the printed paper 10B to the paper ejection stacker 4. It is sent into the storage section 4a. When the paper has been discharged to the paper discharge stacker 4, the printer motor stops, and a reverse start command is again given to the paper feed motor 31 to start the paper feed motor 31 in the reverse direction. Then, when the paper feed motor 31 rotates by the claw type 39 equivalent to 1/4 rotation, it stops again.

When the paper feed motor 31 is reversely rotated, the rotation of the drive gear 34 is transmitted to the claw type 3 through the reverse operation gear trains 35a to 35d.
9 and -tooth gear 40, and rotates the pawl mold 39 and -tooth gear 40 about 1/4 turn in the direction of the arrow from the state shown in FIG. Then, the rack teeth 45 of the temporary movable rack 45
The toothed gear 40, which had been meshed with the rack teeth 45a, disengages from the rack teeth 45a, and the lock on the movable rack plate 45 is released accordingly. The pinion 27 is pushed back to the b side, and this pushing back action causes the pinion 27 to
a, 27b have their respective fixed ranks 47.48 above
4 from the state shown in FIG. 4 in the direction of arrow F, and by rotating the binion 27b in the direction of the arrow due to this transfer, the movable rack plate 45 is returned from the state shown by the solid line in FIG. 14 to the state shown by the two-dot chain line, and the pressure plate The laminated paper 10A on 22a and 22b is pressed against paper feed rollers 24a and 24b.

It should be noted that when the pressure plates 22a, 22b return, highly viscous oil is applied within the sliding groove 45Δ between the guide protrusion 46 of the movable rack plate 45, which slides back in conjunction with this. This viscous oil causes the movable rack plate 45 to
An oil damper function is generated, and the pressure plates 22a and 22b, which are pushed back by the spring pressure of the pressure spring 23, are slowly operated. This prevents the pressure plate from returning in an impactful manner, thereby preventing the generation of noise, vibration, and the paper 10A from bouncing within the paper feed stacker 18.

Furthermore, when the mold wheel 39 is rotated approximately 1/4 turn in the direction of the arrow in FIG.
Since it is located more to the left, the mold wheel 39 including the gear gear 40 is rotated in the direction of the arrow in FIG. 14 by the spring force of the tension spring 41 and automatically returned to the original position shown in FIG. Waits for the next paper feed.

Hereinafter, the series of operations described above is performed every time a sheet of paper is fed by the paper feeding unit.

Next, the retreating operation of the pressure plates 22a and 22b when the amount of paper 10A stored in the paper feed stacker 18 changes will be described.

15(A) to 15(C) are cases where the amount of paper on the paper feed stacker 18 has decreased, and as shown in FIG. 15(A), the amount of stacked paper 10A, that is, the thickness Sagat
As shown by
Approaching the 24b side, pressure play) 22
a, 22b feed the stacked paper 10A to paper feed rollers 24a, 24.
Position F of pinions 27a and 27b when pressing against b
AI is mounted on a fixed rack 47.4 as shown in Figure 15 (B).
It is located on the forward end side of 8. Also, the binions 27a, 2
7b is positioned on the forward end side of the fixed rank 47, 48, the movable rack plate 45 that meshes with the pinion 27b also moves toward the paper feed roller side, and the single-tooth gear 40 is moved against the rack teeth 45a of the movable rack plate 45. The meshing position will change. However, - the toothed gear 40 is rotated in the direction of arrow R by 1/2 rotation of the gear 35d, and - the toothed gear 40 moves from the meshing start point shown in FIG. 15(B) to the gear 35d shown in FIG. 15(C). Since the angle θ up to the end point of 1/2 rotation is approximately constant, the movable rack plate 45
is moved in the direction indicated by the arrow, the pinion 27b that meshes with the rack tooth 45b is transferred from the position indicated by the two-dot chain line in FIG. 15(C) to the position P indicated by the solid line by an interval on the fixed rack 47. do. That is, even if the amount of paper stored in the paper feed stacker 18 decreases, the pressure plate 22a,
The amount of movement that 22b retreats from the position where it presses the stacked paper 10A against the paper feed rollers 24a, 24b is approximately constant, and as a result, the distance between the paper feed rollers 24a, 24b and the stacked paper 10 is approximately constant.
The gap G generated between A is approximately constant.

Figures 16(A) to 16(C) show the situation when the amount of paper 10A stacked on the paper feed stacker 18 is large and its thickness is t2. As shown, when the thickness of the stacked paper sheets 10A becomes 2,
Pressure plates 22a, 22 according to this thickness t2
b separates from the paper feed rollers 24a and 24b, and accordingly, the pressure plate moves the stacked paper 10A to the paper feed roller 24a.
.

The position PA2 of the pinions 27a and 27b when they are pressed against the fixed rack 47 is as shown in FIG. 16(B).
．． It is located approximately in the middle of 48. In addition, the binion 27a,
As the movable rack plate 27b is positioned in the middle of the fixed rack, the movable rack plate 45 that engages with the binion 27b also moves in the direction away from the paper feed roller. However, when the pressure plate is retracted, as the gear gear 40 is rotated 1/2 from the reference position in the direction of arrow R, as shown in FIG.
Since the angle θ from the engagement start point in B) to the end point of 1/2 rotation shown in FIG. 16(C) is approximately constant, this angle θ
When the movable rack plate 45 is moved in the direction of the arrow by an amount corresponding to , the pinion 27b is also moved in the same direction by an interval, as in the case of FIG. As a result, even if many sheets of paper are stacked, the pressure plate 22a
, 22b, the paper feed rollers 24a, 24b
The gap G generated between the paper and the laminated paper 10A is always constant.

In this embodiment as described above, the forward rotation of the paper feed motor 31 rotates the paper feed rollers 24a and 24b in the paper feeding direction to feed the paper 10A on the pressure plate 22a22b to the printer unit 1, so that the paper 10A When the feeding end portion of the paper feed roller 8a, 8b of the printer unit is caught by a predetermined amount, the paper feed motor 31 is reversely rotated by a predetermined amount, and the movable rack plate 45 is slid by the one-tooth gear 40.
At the same time, the pinion 27b and pinion 27a that mesh with the movable rack plate 45 are transferred along the fixed racks 47 and 48, thereby forming the pressure plate 22a.

22b is moved backward against the pressure spring 23, and this retreated position is held by the mold wheel 39 and the pawl 42 that is engaged therewith to separate the laminated paper from the paper feed rollers 24a and 24b. The binding force on the paper on the paper unit side is removed, and the paper feeding load on the paper feed roller on the printer side is accordingly reduced, and the contact state of the paper feed rollers 8a and 8b and 9a and 9b is reduced to the level of linear contact. In addition to being able to feed the paper stably and reliably even with contact pressure, by reducing the contact pressure between the paper feed rollers, the shaft that supports the paper feed rollers and its support mechanism can be constructed with low-strength materials. Since the capacity of the feed roller drive motor can also be reduced, a lightweight and inexpensive printer can be obtained.

In addition, pinions 2'7a and 27b provided at both ends of the pressure plate shaft 25 are connected to respective fixed racks 47 and 48.
The movable rack plate 45, which is slid by the toothed gear 40, is meshed with one of the pinions 27b, so that the paper pressing position of the pressure plate is automatically adjusted according to the amount of stacked paper. Accordingly, the paper feed rollers 24a and 24b are adjusted to the gap between the stacked paper sheets 10A when the pressure plate retreats, without using the drive source of the side structure and regardless of the amount of paper stacked on the paper feed stacker 18. can be kept constant, and
The amount of movement of the stacked paper is reduced, and it is possible to prevent paper misalignment and buckling caused by the movement.

Furthermore, since there is no need for an actuator or sensor dedicated to the backward movement as in the past, the structure is simple and the operation is accurate, and furthermore, the backward movement is small and time loss can be prevented.

In addition, the paper feeding operation and pressure plate retraction operation are 1
Since this is done using two paper feeding motors, the weight of the automatic paper feeding unit can be reduced.

In the above embodiment, the pinions 27a, 27b fixed to the pressure plate shaft 25 and the rack teeth 45a, 45b meshing with the pinions 27a, 27b are moved forwardly. The movable rack 45 may be directly attached to the movable rack 25 or may be integrally configured.

In this example, the movable rack 45 has rack teeth 45a at the top that mesh with the one-tooth gear 40, and rack teeth 45a at the bottom.
It has a surface 45d that slides on the ridges of the teeth. Since the movable rack 45 is rotatably supported on the pressure plate shaft 25, the pressure plate 22a
, 22b can be moved back and forth. Moreover, the left pinion 27b is shown in the drawing. When the pressure plate 22b is moved backward with the left sliding lever, the right pinion 27a also rotates in synchronization with the rotation of the left pinion 27b, making it possible to obtain the same amount of movement on both sides.

Further, in the above embodiment, the paper feeding operation of the paper feeding rollers 24a, 24b and the pressure brake 22a.

Although a case has been described in which a gear train is used as the rotation transmission mechanism for the backward operation of 22b, the structure is not limited to this, and a structure using a toothed belt, gears, etc. may be used.

Further, the mechanism for locking the pressure plates 22a, 22b in the retreat position is not limited to the model wheel and the claw blade type that stops on the model wheel as in the embodiment, and the means for applying the retreat operation force to the movable rack plate is - Not limited to tooth gears, cams,
Alternatively, a model wheel may be provided with a member having a large friction coefficient that engages with the movable rack plate.

〔Effect of the invention〕

As described above, according to the present invention, the reverse rotation of the paper feed motor is transmitted via the rotation transmission mechanism to the mechanism consisting of the movable and fixed racks and the pinion meshing with the racks, thereby causing the pressure plate to act as the pressing means. The stacker is moved backwards against the pressure, and this backward position is held by a holding mechanism to separate the stacked paper on the pressure plate from the paper feed roller, so the amount of paper stored in the paper feed stacker is Even if the pressure plate changes, the gap formed between the stacked paper and the paper feed roller due to the backward movement of the pressure plate can be kept constant and small, and the stacked paper can be prevented from becoming misaligned or buckling. . Further, since the paper feed motor can also be used as the drive source for the backward movement of the pressure plate, it is possible to reduce costs and weight.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing an example of an automatic paper feeder according to the present invention. FIG. 2 is a partially cutaway side view of a printer unit equipped with an automatic paper feeder according to the present invention. FIG. 3 is a side view of the paper feed motor and drive mechanism in the paper feed unit in this embodiment. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3. FIG. 5 is a cross-sectional view taken along the line -V in FIG. 3 as well. FIG. 6 is a sectional view showing details of the paper feed roller shaft and one-way bearing portion in this embodiment. FIG. 7 is a sectional view showing details of the pressure plate retraction gear portion in this embodiment. FIG. 8 is a side view of the pressure plate retraction mechanism in this embodiment. FIG. 9 is a sectional view taken along line IX-IX in FIG. 8. FIG. 10 is an enlarged vertical sectional side view showing the paper feed stacker portion in this embodiment. FIG. 11 is a sectional view for explaining the operation of the paper feed stacker in this embodiment. 12 to 14 are explanatory views of the operation of the pressure plate retraction mechanism in this embodiment. FIGS. 15(A) and 15(B) are operation explanatory diagrams showing the relationship between the amount of paper accommodated in the paper feed stacker and the pressure plate retraction mechanism of this embodiment. FIGS. 16A to 16C are operation explanatory diagrams showing the relationship between the amount of paper accommodated in the paper feed stacker and the pressure plate retraction mechanism of this embodiment. FIG. 17 is a side view showing another example of the rack mechanism according to the present invention. FIG. 18 is a side view of FIG. 17. FIG. 19 is a sectional view of FIG. 17. [Description of symbols of main parts] 1... Printer unit 2... Automatic paper feed unit 17... Frame body 18... Paper feed stackers 22a, 22b... Pressure plates 2-4a, 2
4b...-Paper feed roller 25...Pressure plate shafts 27a, 27b...Pinion 28...Paper feed roller shafts 29a to 29e...Gear 30.37...One-way bearing 31... -Paper feed Motors 35a to 35d...Gear 39...Model wheel 40...-Tooth gear 41...Tension spring 42...Claw 45...Movable rack plate 47.48...Fixed rack 49...・Paper sensor. Figure Figure 8 E Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure

Claims (1)

[Claims] (1) a pressure plate that is swingably supported by the stacker frame body in the front and back direction and presses the stacked paper; a paper feed roller that is located in front of the pressure plate and rotatably supported by the frame body; a pressing means for pressing the stacked paper against the paper feed roller via a pressure plate; a paper feed motor that is attached to the frame body and capable of forward and reverse rotation; a rack mechanism for advancing and retracting the pressure plate, which has a rack plate that moves in accordance with the moving direction of the pressure plate; and a rack mechanism for transmitting the reverse rotation of the paper feed motor to a movable rack of the rack mechanism. An automatic paper feeder comprising: a rotation transmission mechanism that moves the pressure plate backward against the pressing means; and a holding mechanism that holds the pressure plate in the retreated position.