JPH08142442A - Thermal printer - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to a thermal printer, and an object of the present invention is to realize a thermal printer in which head-up operation during paper replenishment is automated. [Structure] In a line thermal printer having an automatic paper feed function, a reverse movement of a motor, which is a drive source for the automatic paper feed function, is used as a power source for the automatic head up / down function.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal printer having an automatic head-up / down function of a small line thermal printer for printing forms, which has an automatic paper feeding function.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional thermal printer having an automatic paper feeding function. As shown in the figure, it comprises a printer unit 1 and a paper cassette unit 2 which is detachable from the printer unit 1. The printer unit 1 comprises a line thermal head 3, a printing unit 5 including a platen 4, and a paper feed roller. 6, a platen (not shown), a paper feed roller drive unit, a printing circuit unit, and the like. The paper cassette unit 2 presses the paper storage unit that holds the paper 7 and the paper feed roller 6 of the printer unit. The pressure roller 8 and the like are provided.

The sheet 7 is supplied from the sheet cassette section 2 to the printing section by the sheet feeding roller 6, and the line thermal head 3 prints the sheet. Paper 7 in the paper cassette 2
If there is no paper, remove the empty paper cassette unit 2 from the printer unit 1, replenish the paper 7, and then mount it again on the printer unit 1 and press the manual button to rotate the drive motor of the paper feed roller 6. The paper 7 is guided to the printing unit 5 and set.

[0004]

In the above conventional line thermal printer, when the paper 7 is replenished and introduced between the platen 4 and the thermal head 3 of the printing unit 5, the thermal head 3 is separated from the platen 4 ( Head-up operation)
It is necessary to make a gap. Conventionally, this head-up operation has been performed manually, which causes a problem of increasing the burden on the operator.

In view of the above-mentioned conventional problems, the present invention aims to realize a thermal printer in which the head-up operation at the time of replenishing paper is automated to reduce the burden on the operator.

[0006]

According to the thermal printer of the present invention, in a line thermal printer having an automatic paper feeding function, a reverse movement of a motor as a drive source for the automatic paper feeding function is automatically headed up and down. It is characterized by having been used as a power source of. In addition to that, the down operation of the thermal head 25 is performed by a pressurizing unit that presses the thermal head 25 against the platen 26.

The head-up operation is performed by the rotary cam 21, and the head-up gear 20 coaxially fixed to the rotary cam 21 is moved from the motor 10 to the drive gear 13.
It is also characterized in that it is driven via the one-way clutch 17. Further, the present invention is characterized in that a rotary drive means for manually rotating the rotary cam 21 is provided. By adopting this configuration, it is possible to obtain a thermal printer capable of performing head-up / down operation during paper feeding and paper feeding by one motor.

[0008]

First, the motor 10 is moved from the state shown in FIG.
The feed roller driving gear 12 meshing with the pinion gear 11 is rotated in the arrow B direction, and the rotary cam driving drive gear 13 is rotated in the arrow C direction. In this case, the gear 12 does not transmit the rotation to the rotating shaft 15 due to the action of the one-way clutch 14. Meanwhile drive gear 1
Reference numeral 3 causes the fan gear 19 to rotate in the direction of arrow C via the shaft 18 by the action of the one-way clutch 17.

The rotating fan-shaped gear 19 hits the head-up gear 20 as shown in FIG.
0 starts to mesh and rotates while rotating the head-up gear 20 in the direction of arrow D, but the rotation of the motor 10 is stopped slightly before the mesh is disengaged. In this state, the head-up gear 20 is rotated by the rotary cam 21 via the rotary shaft 22.
Is rotated, and the rotary cam 21 has its cam mountain 21a.
Then, the thermal head 25 is pushed up to be in a head-up state.

When the motor 10 is rotated in the reverse direction (in the direction of arrow A ') as shown in FIG. 2B in this head-up state, the pinion gear 11 rotates the paper feed roller 16 via the gear 12 and the one-way clutch 14, and the paper 28 can be introduced into the printing unit 24. Next, the head-down operation is shown in FIG.
As shown in (c), the motor 10 is further rotated in the reverse direction to rotate in the direction of arrow A, and the fan gear 19 is rotated in the direction of arrow C to disengage from the head-up gear 20. The disengaged head-up gear 20 becomes free together with the rotary cam 21, and the slope of the cam mountain of the rotary cam 21 is pressed by the thermal head 25 to rotate in the direction of arrow D ', and the thermal head 25 is lowered. .

[0011]

1 is a perspective view showing the outline of a first embodiment of the present invention. This embodiment comprises a printer unit and a paper cassette unit which can be attached to and detached from the printer unit, as in the conventional example described with reference to FIG. FIG. 1 shows only the internal mechanism of the printer unit and the pressing roller of the paper cassette unit. In the figure, reference numeral 10 is a motor capable of forward and reverse rotations, and a pinion gear 11 is attached to its rotation shaft. The pinion gear 11 has a gear 12 for driving a paper feed roller and a drive gear for driving a rotary cam. 13 is in mesh. The feed roller driving gear 12 is attached to the rotary shaft 15 via a first one-way clutch 14 that transmits power only in the arrow B direction, and the feed roller 16 is attached to the rotary shaft 15.

The drive gear 13 for driving the rotary cam has a second one-way clutch 17 that transmits power only in the direction of arrow C.
Is attached to the rotary shaft 18 via a fan-shaped gear 19 fixed to the rotary shaft. A head-up gear 20 is meshable with the fan-shaped gear 19 and is fixed to a rotary shaft 22 having a rotary cam 21 at one end. In addition,
The head-up gear 20 is fan-shaped in the drawing, but may be circular. Reference numeral 23 is a stopper that determines the position of the rotary cam 23.

Reference numeral 24 is a thermal head 25 and a platen 2.
The thermal head 25 has one end swingably supported by fulcrums 25a and 25b, and the other end is urged by a spring 27 so as to contact the rotating cam 21. Further, 28 is a sheet, 29 is the sheet feeding roller 16
It is a pressing roller that presses against.

The operation of this embodiment thus constructed will be described with reference to FIG. First, to head up,
(A) The motor 10 is rotated in the direction of arrow A (counterclockwise) from the initial state in the figure. Then, the pinion gear 11 rotates the feed roller driving gear 12 in the direction of arrow B (clockwise), but the rotation shaft 15 does not rotate due to the first one-way clutch 14. Therefore, the paper feed roller 16 remains stationary. On the other hand, the drive gear 1 meshing with the pinion gear 11
3 is rotated in the direction of arrow C (clockwise) to rotate the fan gear 19 in the direction of arrow C via the second one-way clutch 17 and the rotary shaft 18.

When the fan-shaped gear 19 reaches the head-up gear 20, it meshes with the gear and rotates the gear 20 and the rotary cam 21 in the direction of arrow D (counterclockwise) as shown in FIG. Then, the fan-shaped gear 19 is slightly out of mesh with the head-up gear 20 (state shown in Fig. B).
The rotation of the motor 10 is stopped with.

In this state, the rotary cam 21 lifts the thermal head 25 against the urging force of the spring 27 (that is, head-up operation), and creates a gap between the thermal head 25 and the platen 26 to introduce the paper 28. Of.

When the motor 10 is reversely rotated in the direction of arrow A '(clockwise) in the state shown in FIG. 3B, the feed roller driving gear 12 is rotationally driven in the direction of arrow B'and the first one-way clutch. Paper feed roller 16 via the rotary shaft 14 and the rotary shaft 15.
Can be rotated to supply the paper 28 to the printing unit 24. On the other hand, the drive gear 13 is in the direction of arrow C '(counterclockwise).
The fan gear 19 is stationary because the second one-way clutch 17 does not transmit power to the rotary shaft 18. Therefore, the head-up state is maintained and the paper 28 can be introduced.

Next, in the head-down operation, the motor 10 is rotated in the direction of arrow A (counterclockwise) from the state shown in FIG. 7B to the drive gear 13, the one-way clutch 17, as shown in FIG.
The fan gear 19 is rotated in the direction of arrow C via the rotary shaft 18 to disengage from the head-up gear 20. The disengaged head-up gear 20 and the rotary cam 21 become free, and the rotary cam 21 is pressed by the thermal head 25 on the slope of the cam lobe and rotated in the arrow D'direction (clockwise direction), as shown in FIG. After returning to the state, the thermal head 25 descends and holds the paper 28 between it and the platen 26. As described above, the sheet conveyance and the head up / down operation can be performed by one motor.

FIG. 3 is a diagram showing a main part of a second embodiment of the present invention. In this embodiment, a manual head-up mechanism is added to the first embodiment so that the head-up can be performed manually when the paper is jammed. Therefore, only the added portion will be described.

In this embodiment, as shown in FIG. 3A, a gear 30 is formed on the boss portion of the head-up gear 20, and the gear 30 can mesh with the gear 30 and is supported by a spindle 31a. A manual lever 32 having a gear 31 is provided, and the manual lever 32 has a lever 3 having a leaf spring 33 near the tip thereof.
4 and the pressing portion 35 are provided, and the spring 36 urges them in the counterclockwise direction so that the fan-shaped gear 31 does not always mesh with the gear 30 of the head-up gear.

A locking lever 38 having a locking claw 37 capable of locking the lever 34 of the manual lever 32, swingably supported by a fulcrum 38a, and biased upward by a spring 39. Is supported by a pin 40a and has two grooves and is rotatably driven by pressing one of the grooves by a leaf spring 33 of the manual lever 32 to move the locking lever 38 up and down. A moving piece 40, a ball 41 that holds the swing piece 40 at two positions, and a spring 42 that presses the ball are provided.

The operation of this embodiment thus constructed will be described with reference to FIG. FIG. 3A shows the initial state, and the thermal head 25 is in contact with the platen 26. In this state, the pressing portion 35 of the manual lever 32 is first pushed down in the arrow Z direction. Then, the manual lever is rotated clockwise as shown in FIG.
The head-up gear 20 and the rotary cam 21 are rotated counterclockwise by meshing with the gear 30 of FIG. As a result, the rotary cam 21 lifts the thermal head 25 with the mountain of the cam and creates a clearance between the rotary cam 21 and the platen 26.

On the other hand, the leaf spring 33 of the manual lever 32 presses the groove on the upper portion of the swing piece 40, rotates the swing piece 40 counterclockwise, and moves the tip of the locking lever 38 upward. . Next, when the pressing of the pressing portion 35 of the manual lever 32 is released, the manual lever 32 returns counterclockwise by the urging force of the spring 36 as shown in FIG. To be done. Since this return is slight, the rotation of the head-up gear 20 is also small, and therefore the head-up operation is maintained.

Next, to perform the head-down operation,
(D) The pressing portion 35 of the manual lever 32 is pressed again as shown in the figure. Then, the leaf spring 33 of the manual lever 32 presses the groove in the lower portion of the swinging piece 40 which is rotating counterclockwise,
The swing piece 40 tilts clockwise and pushes the tip of the locking lever 38 downward. Then, when the pressing of the pressing portion 35 is released, the lever 34 of the manual lever 32 rotates counterclockwise without being locked by the locking claw 37 of the locking lever 38 and returns to the state shown in FIG. At the same time, the head-up gear 20 and the rotary cam 21 are also returned to the initial state and the head-down operation is performed.

[0025]

According to the present invention, in a line thermal printer having an automatic paper feeding function, the reverse movement of a motor, which is a driving source for automatic paper feeding, is used as a power source for an up-down function of a thermal head. By automating the down operation, the burden on the operator can be reduced,
In particular, it is effective in saving labor in a portable printer for printing forms.

[Brief description of drawings]

FIG. 1 is a perspective view showing an outline of a first embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of the first embodiment of the present invention.

FIG. 3 is a diagram showing a main part of a second embodiment of the present invention and explaining the operation thereof.

FIG. 4 is a diagram showing a conventional line thermal printer having an automatic paper feeding function.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Motor 11 ... Pinion gear 12 ... Feed roller driving gear 13 ... Drive gear 14 ... First one-way clutch 15, 18, 22 ... Rotating shaft 16 ... Paper feed roller 17 ... Second one-way clutch 19 ... Fan-shaped Gear 20 ... Head up gear 21 ... Rotating cam 23 ... Stopper 24 ... Printing part 25 ... Thermal head 26 ... Platen 27, 36, 39, 42 ... Spring 28 ... Paper 29 ... Pressing roller 32 ... Manual lever 33 ... Leaf spring 34 ... Lever 35 ... Pressing part 37 ... Locking claw 38 ... Locking lever 40 ... Rolling piece 41 ... Ball

Claims (4)

[Claims] 1. A line thermal printer having an automatic paper feeding function, wherein a reverse movement of a motor, which is a drive source for the automatic paper feeding function, is used as a power source for the automatic head up / down function. 2. The down operation of the thermal head (25) is performed by pressurizing means for pressing the thermal head (25) against the platen (26).
Thermal printer. 3. The rotating cam (2
1), and driving the head-up gear (20) coaxially fixed to the rotary cam (21) from the motor (10) via the drive gear (13) and the one-way clutch (17). The thermal printer according to claim 1, which is characterized in that. 4. The thermal printer according to claim 3, further comprising rotation driving means capable of manually rotating the rotation cam (21).