JPH0741717Y2 - Paper feeder - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sheet feeding device used in a printing device.

2. Description of the Related Art Conventionally, as shown in FIG. 5, a guide plate 101 fixed to a housing extending toward a lower portion of a supply destination such as a platen 100,
The guide plate 101 is provided with a paper feed roller 102 that faces the guide plate at a predetermined interval, and a pressure contact plate 104 that supports a plurality of single-cut sheets 103 in a stacked state is provided on the guide plate 101 by a shaft 105 provided on the upstream side. It is mounted so that it can oscillate so that the downstream side oscillates, and this pressure contact plate 104 is biased upward by a compression coil spring 106 so
There is an apparatus in which 103 is pressed against the paper feed roller 102.

Further, as shown in FIG. 6, there is a configuration in which the pressure contact plate 104 is biased by a conical coil spring 107 instead of the compression coil spring 106.

Further, FIG. 7 shows a state in which the press-contact plate 104 is viewed from the back surface. A plurality of U-shaped plates 108 are fixed to the back surface of the press-contact plate 104, and the flanged pins 109 are inserted into these plates 108. Legs 111, which block the axial movement of these flanged pins 109 by a retaining ring 110 and elastically contact the pressure contact plate 104 and the guide plate 101,
The torsion coil spring 113 having the 112 formed therein is provided with a flanged pin 109.
Wound on the pressure contact plate 1 by these torsion coil springs 113.
There is a thing that biases 04 upward.

However, in the device shown in FIG. 5, since the pressure contact plate 104 shows a rotational movement, the compression coil spring 106 bends by receiving a reaction force inclined with respect to its axis, As a result, the press contact plate 104
The force for urging may weaken.

Further, in the structure shown in FIG. 6, since the spring constant changes depending on the amount of bending of the conical coil spring 107, the pressure contact force with respect to the paper feed roller 102 depends on the number of cut sheets 103 on the pressure contact plate 104. May become unstable.

Further, the one shown in FIG.
Since 3 receives a torsional load around the axis, the spring constant can be easily reduced by increasing the number of windings.
Even if the rotation angle of the press contact plate 104 (the number of stacked sheets 103) changes, the change in the force of pressing the cut sheet 103 against the paper feed roller can be reduced. However, since the number of parts is large, there is a problem that the assembly work becomes complicated.

Means for Solving the Problems A guide plate fixed to the casing of the printing device so as to extend toward the supply destination, and the casing is rotated so as to face the guide plate at a predetermined interval. At a position between the sheet feeding roller freely attached and the guide plate and the sheet feeding roller, the upstream side is held by the guide plate by the pivot and the downstream side is held so as to be undulated so as to swing. A pressure contact plate that supports a plurality of cut sheets in a stacked state, a torsion coil spring having legs formed at both ends elastically contacting the guide plate and the pressure contact plate, and the guide plate or the pressure contact plate And a support surface that is formed integrally and faces both ends of the coil portion of the torsion coil spring, and that is integrally formed with the support surface at a position downstream of the rotation fulcrum that holds the pressure contact plate. Shaft that is inserted into both ends of the coil of the torsion coil spring And.

Therefore, the leg portion of the torsion coil spring is elastically brought into contact with the guide plate and the pressure contact plate to urge the pressure contact plate, and the cut sheet on this pressure contact plate is pressed against the paper feed roller. Since the torsion coil spring receives a torsion load around the axis, it is possible to increase the number of turns to reduce the spring constant, and thereby reduce the change in the force of the torsion coil spring with respect to the change in the rotation angle of the pressure contact plate, Therefore, the single-cut sheet is pressed against the paper feed roller with a stable force, and the shaft portion inserted into both ends of the coil portion of the torsion coil spring and the support surface supporting these shaft portions are guided or pressed. By integrally forming on the plate, the mounting structure and the assembling work of the torsion coil spring are simplified.

Embodiment An embodiment of the present invention will be described with reference to the drawings. Reference numeral 1 denotes a casing of the printing apparatus. Inside the casing 1, a rotatable platen 2 as a supply destination, a dot printer head 3 facing the platen 2, and a support member 5 for supporting a pinch roller 4 are provided. An arm 7 for biasing the support member 5 toward the platen 2 side by being biased by the compression coil spring 6, a paper pan 8 and a tractor 9 are provided, and a paper insertion port is provided on the back surface.
10 are formed.

In addition, a pinion 11 driven by a motor (not shown), a transmission gear 12 meshed with the pinion 11, and a small-diameter rotating integrally with the transmission gear 12 are provided on one side of the housing 1. A transmission gear 13, a platen gear 14 meshed with the transmission gear 13, and a drive gear which is meshed with the transmission gear 13 and is meshed with the tractor gear 15 by moving in the axial direction.
16, a transmission gear 17 meshed with the drive gear 16, a transmission gear 18 meshed with the transmission gear 17, and the paper feed roller.
Roller gear 19 fixed to one end of 10 and platen gear 14
The transmission gear 20 meshed with the transmission gear 20 and the transmission gear 21 meshed with the transmission gear 20 are rotatably held. A paper discharge roller 22 is directly connected to the transmission gear 21. Further, the transmission gear 18 is supported on the free end side of the rotation of the arm 23 that rotates around the axis of the transmission gear 17.

Further, a guide plate 24 extending downwardly of the platen 2 is fixedly provided on the housing 1, and a paper feed roller 25 facing the guide plate 24 at a predetermined interval is a motor (see FIG. (Not shown) and is rotatably provided. The roller gear 19 is fixed to one end of the shaft portion of the paper feed roller 25. On the guide plate 24, a pressure contact plate 27 that supports a large number of single-cut sheets 26 in a stacked state is provided on the upstream side and serves as a rotation fulcrum.
It is mounted so that it can be raised and lowered by 28 so that the downstream side swings. The torsion coil spring 29 for urging the pressure contact plate 27 upward has a leg 30 elastically contacting the lower surface of the pressure contact plate 27 and a leg 31 elastically contacting the guide plate 24. . The torsion coil spring 29 is located in the opening 32 formed on the downstream side of the position where the shaft 28 of the guide plate 24 is provided, and the coil of the torsion coil spring 29 is provided on both sides of the opening 32. The support surfaces 33 that contact both ends of the part and these support surfaces 33
A shaft portion 34 projecting from and inserted into both ends of the coil portion of the torsion coil spring 29 is integrally formed. Further, a paper stand 35 located on the extension surface of the pressure contact plate 27 is fixed to the end of the cover 36.

With such a configuration, when printing on the cut sheet 26,
The cut sheets 26 are stacked and inserted between the pressure contact plate 27 and the feed roller 25, supported by the paper stand 35, and the release lever (not shown) is operated to move the platen 2
The pinch roller 4 is brought into pressure contact with and the arm 23 is released from the release lever to allow clockwise rotation of the drive gear 17 due to frictional force with the drive gear 17 when the drive gear 17 rotates clockwise. Mesh with the roller gear 19. Therefore, rotate the paper feed roller 25 clockwise to
Is fed until the tip reaches the outer periphery of the platen 2,
After that, the platen 2 is fed by rotating the platen 2 in the clockwise direction, and is discharged upward by the paper discharge roller 22.

As described above, the single-cut sheet 26 is pressed against the paper feed roller 25 by the pressing plate 27 and supplied to the platen 2 one by one. Therefore, the press-contact plate 27 gradually rotates toward the paper feed roller 25 as the number of cut sheets 26 decreases. However, since the torsion coil spring 29 that biases the pressure contact plate 27 receives a torsion load around the axis, the spring constant can be easily reduced by increasing the number of turns, and therefore, the number of single-cut sheets 26 is reduced. Even if the rotation angle of the pressure contact plate 27 changes due to the change, the single-cut sheet 26 can be reliably pressed against the paper feed roller 25 with a stable force.

Further, since the torsion coil spring 29 is held by the shaft portion 34 formed integrally with the guide plate 24, the structure for holding the torsion coil spring 29 and its assembling work can be simplified.

The support surface 33 and the shaft portion 34 may be integrally formed with the press-contact plate 27.

Effect of the Invention As described above, the present invention elastically abuts the legs of the torsion coil spring against the guide plate and the pressure contact plate to urge the pressure contact plate, whereby the torsion coil spring twists around the axis. Since the load is applied, the spring constant can be easily reduced by increasing the number of turns. This reduces the change in the force of the torsion coil spring with respect to the change in the rotation angle of the pressure contact plate, and reduces the load on the pressure contact plate. A single sheet can be pressed against the paper feed roller with a stable force regardless of the number of sheets, and a shaft portion inserted at both ends of the coil portion of the torsion coil spring and a support for supporting these shaft portions. By integrally forming the surface and the guide plate or the pressure contact plate, it is possible to simplify the mounting structure of the torsion coil spring and its assembling work.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention. FIG. 1 is an enlarged vertical sectional side view of an attachment structure of a pressure contact plate and a torsion coil spring to a guide plate, and FIG. 2 is a part thereof. FIG. 3 is a partial plan view of FIG. 3, FIG. 4 is a vertical sectional side view showing the entire structure, FIGS. 5 and 6 are vertical sectional side views showing a conventional example, and FIG. It is a perspective view which shows a prior art example. 1 ... printer housing, 2 ... platen (supply destination), 24
...... Guide plate, 25 …… Feeding roller, 26 …… Single sheet, 27 …… Pressing plate, 28 …… Rotation fulcrum, 29 …… Torsion coil spring, 30,3
1 …… Leg, 33 …… Supporting surface, 34 …… Shaft

Claims (1)

[Scope of utility model registration request] 1. A guide plate fixed to a casing of a printing device so as to extend toward a supply destination, and rotatably attached to the casing so as to face the guide plate with a predetermined gap therebetween. A plurality of sheet feeding rollers, and the upstream side is held by the guide plate by a rotation fulcrum at a position between the guide roller and the sheet feeding roller, and the downstream side is rockably supported so as to swing. A pressure contact plate that supports the stacks in a stacked state, a torsion coil spring having leg portions that elastically contact the guide plate and the pressure contact plate at both ends, and the guide plate or the pressure contact plate integrally. The torsion coil, which is formed integrally with the support surface and is located downstream of the rotation fulcrum that holds the pressure contact plate, and the support surface that faces both ends of the coil portion of the torsion coil spring. And a shaft portion inserted into both ends of the coil portion of the spring. Sheet feeding apparatus according to claim and.