JPS6114948B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a paper feeding device for a printer that performs bidirectional printing.

Conventionally, the paper feed device of small printers that print not only when spacing the carriage but also when it returns, so-called bidirectional printing, rotates a rubber roller using a ratchet mechanism or a special motor, and applies frictional force to the paper in contact with the rubber roller. It was sent by

However, the conventional paper feeding device has disadvantages in that the diameter of the rubber roller cannot be made very small, and because it uses a ratchet mechanism and a dedicated motor, it is large, heavy, and expensive.

The present invention eliminates the above-mentioned drawbacks and will be explained in detail below with reference to the drawings.

FIG. 1 and FIG. 2 are a plan view and a side view showing one embodiment of the present tomb opening. 1 and 2, 1 is a motor, 2a and 2b are gears, 3 is a drive shaft connected by the gear 2b, and has two types of clockwise and counterclockwise spiral grooves connected at both ends; 4; 5 is a carriage having a post 4a on the bottom and a projection (not shown) that fits into the spiral groove; a pair of flexible swash plates 5c and 5d
6 is a guide shaft for guiding the carriage 4 in the print line direction;
8 is a guide plate which has friction members 7b and 7c having frictional resistance different from that of the paper guide 7a in the friction direction and guides the swing plate 6 in parallel to the paper feeding direction while supporting the swing plate 6; 8 rotates the guide plate 7; 9 is a leaf spring that biases the guide plate 7 upward; 10 is a spring that biases the guide plate 7 in the paper feeding direction; 11 is a printing paper; 12
is the platen.

The operation in the above configuration will be explained. First, the motor 1 is driven to rotate the drive shaft 3 via the key gears 2a and 2b. This drive shaft 3 is the third
As shown in the figure, it has two types of spiral grooves, one clockwise and one counterclockwise with respect to the axial direction, and these two types of spiral grooves are connected at both ends. A protrusion formed inside the carriage 4 fits into one helical groove of the drive shaft 3. Therefore, as the drive shaft 3 rotates, the carriage 4 moves in one direction according to the one spiral groove, and when it reaches the end, it moves in the other direction according to the other spiral groove, which is reversed. Repeat the exercise. When the motor 1 continues to rotate in one direction in this manner, the carriage 4 reciprocates. When this carriage moves, for example, from the left end to the right as described above, the post 4a of the carriage 4 eventually comes into contact with the flexible swash plate 5e, causing it to bend as shown in FIG. 5A.
Therefore, the post 4a passes between the projection 5a and the flexible swash plate 5e. When the carriage 4 moves further to the right, the post 4a moves to the flexible swash plate 5d.
F as shown in FIG. 4 on this flexible swash plate 5d.
Add force. As shown in FIG. 4, this force F can be divided into a component force F _A parallel to the inclination of the flexible swash plate 5d and a component force F _B parallel to the paper feeding direction. As the carriage 4 moves, it moves in the direction of the arrow in FIG. 5B, that is, in the opposite direction to the paper feeding direction. At this time, the printing paper 11 in contact with the friction member 5e of the rocking plate 5 receives a force from the friction member 5e in the opposite direction to the paper feeding direction; Since the frictional resistance of the friction members 7b and 7c of the guide plate 7 is greater than the frictional resistance, the printing paper 11 is not fed. The spring 10 is also compressed and accumulates biasing force. In this way, when the post 4a moves further to the right from the position shown in FIG. move in the direction. At this time, the printing paper 11 in contact with the friction member 5e of the rocking plate 5 receives a force in the paper feeding direction from this friction member 5e, and at this time, the friction members 7b and 7c of the guide plate 7
Friction member 5e of rocking plate 5 due to the frictional resistance of
Since the frictional resistance is large, the printing paper 11 is sent in the paper feeding direction. Further, the carriage 4 is at the right end at this time, so no printing is performed on the printing paper 11 during movement. After that, when the carriage 4 moves from the right end to the left as described above, the post 4a of the carriage 4 eventually comes into contact with the flexible member 5d, causing the flexible member 5d to bend as shown in FIG. 5D. It then passes between the protrusion 5a and the flexible swash plate 5d, and then comes into contact with the flexible swash plate 5c to move the rocking plate 5 against the biasing force of the spring 10. At this time, the printing paper 11 is not fed, and a biasing force is accumulated in the spring 10. Thereafter, the swing plate 5 is moved in the direction of the arrow shown in FIG. 5E until the post 4a is at the position shown in FIG. Print paper 11 is fed in the paper feeding direction. At this time, the carriage 4 is at the left end, and no printing is performed on the printing paper 11 during movement.

Therefore, printing is performed while the carriage 4 is moving from the left end to the right, and just before the carriage 4 reaches the right end, the printing paper 11 is fed by one line, and while the carriage 4 is moving from the right end to the left. , and just before this carriage 4 reaches the left end, print paper 1
1 can be fed by one line, and so-called bidirectional printing is possible.

Note that when the printing paper 11 is not loaded, the friction member 5e of the swing plate 5 is in direct contact with the bottom surface of the platen 12, and when the swing plate 5 is moved in the paper feeding direction in this state, the platen 11 A large frictional force (so-called "stickiness") is generated between the bottom surface of the friction member 5e and the friction member 5e. In this embodiment, when the frictional force becomes large to a certain extent, the guide plate 7 pivots around the rotating plate 8, causing the deflection of the leaf spring 9. Since the friction member 5e rotates counterclockwise against the force, the friction member 5e will not be deformed or damaged.

FIGS. 6A, 6B, and 6C are views showing friction members suitable for the embodiment described above. Said Figure 6 A,
B and C, since the friction member has a shape in which the fixed part 13 and the movable part 14 are connected by a thin bending part 15, it is easy to bend at the bending part 15. For this reason, for example, the printing paper 11
When the paper is fed in the opposite direction to the paper feeding direction, the friction member 5e is deformed as shown in FIG. 6B, and the apex A is lowered by ΔP compared to FIG. 6A, resulting in a lower frictional resistance. For example, printing paper 11
When the paper is fed in the paper feeding direction, the friction member 5e is deformed as shown in FIG. 6C, and the apex A has a higher ΔP' and a higher frictional resistance than in FIG. 6B.

FIG. 7 is a diagram showing the main parts of another embodiment according to the present invention, in which backing plates 16a and 16b are provided on the backs of flexible swash plates 5c and 5d, respectively, and these backing plates 16a allow flexible slanting Since the plate 5c is prevented from bending to the left and the flexible swash plate 5d is prevented from bending to the right by the backing plate 16b, the spring properties of the flexible swash plates 5e and 5d are weakened. The swing plate 5 can also be moved, and the carriage can be moved using a low torque motor.

Note that the present invention is not limited to the above embodiments, but includes, for example,
The flexible swash plate and the rocking plate may be integrally molded from plastic, or the swash plate may be a non-flexible plate and the tip of the swash plate may be biased by a spring so that it comes into contact with the protrusion of the rocking plate. It's okay.

As described in detail above, according to the present invention, the swing plate receives a force from the carriage and moves in the opposite direction to the paper feeding direction until the carriage reaches the end; a spring that accumulates a biasing force when gradually moving in the opposite direction to the paper feeding direction, and moves the rocking plate in the paper feeding direction by the accumulated biasing force when the carriage is located at the end; A friction member is attached to the moving plate and exhibits high frictional resistance only in the paper feeding direction, and the printing paper is fed by the friction member when the swinging plate moves in the paper feeding direction. In addition, since a ratchet mechanism or a dedicated motor is not required, it is lightweight and inexpensive.

[Brief explanation of the drawing]

1 and 2 are a plan view and a side view showing an embodiment of the present invention, FIG. 3 is an enlarged view of parts of the embodiment shown in FIGS. 1 and 2, and FIG. are vector diagrams explaining the operation of the embodiment shown in FIGS. 1 and 2, and FIGS.
FIG. 6 is a plan view illustrating the operation of the embodiment shown in FIGS. FIG. 1...Motor, 2a and 2b...Gear, 3...
... Drive shaft, 4... Carriage, 4a... Post, 5... Rocking plate, 5a and 5b... Protrusion,
5c and 5d... Flexible swash plate, 5e... Friction member, 6... Guide shaft, 7... Guide plate, 7a... Paper guide, 7b and 7c...
Friction member, 8... Rotating shaft, 9... Leaf spring, 10... Spring, 11... Printing paper, 1
2... platen, 13... fixed part, 14... movable part, 15... bending part, 16a and 16b... backing plate.

Claims (1)

[Claims] 1. In a paper feeding device of a printer that is equipped with a carriage that reciprocates in the printing line direction and prints during spacing and return, it receives a force from the carriage in the paper feeding direction until the carriage reaches the end. a rocking plate that moves in opposite directions;
a spring that accumulates a biasing force when the rocking plate moves in a direction opposite to the paper feeding direction, and moves the rocking plate in the paper feeding direction by the accumulated biasing force when the carriage is located at the end; and a friction member that is attached to the swing plate and exhibits high frictional resistance only in the paper feed direction, and the printing paper is fed by the friction member when the swing plate moves in the paper feed direction. Features of printer paper feeding device.