JPH0776149A - Thermal printer - Google Patents

Abstract

(57) [Summary] [Object] To provide a small-sized and inexpensive thermal printer in which the number of parts is reduced by carrying a sheet, moving up and down a thermal head, and carrying an ink ribbon with one motor. [Structure] An operation of transmitting drive to a contacting / separating means 4 by a first drive transmitting means 2a, 2b, 3 to bring a thermal head 6 into contact with and separating from a platen 10, and a second drive transmitting means 2
Drive is transmitted to the sheet conveying means 7, 8, 9 and 10 by a and 2c so that the sheet 2 is conveyed between the thermal head 6 and the platen 10.
2 and the third drive transmission means 11 and 1
A single motor performs the operation of transmitting the drive from the motor to the ribbon transporting means 26 by 2 and 13 to transport the ink ribbon 23 between the thermal head 6 and the paper 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line-type thermal printer, and more particularly to a thermal printer which drives up and down of a thermal head, paper conveyance and ink ribbon conveyance by one motor.

[0002]

2. Description of the Related Art In a thermal printer, it is necessary to sandwich a sheet between a thermal head and a platen when printing. As a method of sandwiching, the thermal head is manually or automatically moved by using an actuator such as a motor.

[0003]

However, in the case of manual operation, no motor is required, but a large amount of force is required to obtain an appropriate head pressing pressure. Further, in the case of automatic operation, an actuator such as a motor for moving the thermal head is additionally required, which has been a factor of increasing the size of the product and increasing the cost.

The thermal printer of the present invention has been made in view of the above problems, and the purpose thereof is to convey paper by one motor and up / down operation of the thermal head, and further convey ink ribbon. Is to reduce the number of parts and to provide a small-sized and inexpensive thermal printer.

[0005]

In order to achieve the above object, the thermal printer of the present invention has a thermal head in which a plurality of heating elements are arranged in an array in the main scanning direction, and is arranged to face the thermal head. A platen, a contacting / separating means for contacting / separating the thermal head with respect to the platen, a sheet conveying means for conveying a sheet between the thermal head and the platen, and a ribbon for conveying an ink ribbon between the thermal head and the sheet. In a thermal printer having a conveyance means, a motor, and a first drive transmission means for transmitting drive from the motor to the contacting / separating means,
A second device for transmitting drive from the motor to the paper transporting means
Drive transmission means and third drive transmission means for transmitting drive from the motor to the ribbon transport means, and the single motor drives the contact / separation operation of the thermal head and the platen, the transport of the sheet, and the ink ribbon. Carry out.

[0006]

That is, in the thermal printer of the present invention, the operation of transmitting the drive from the motor to the contacting / separating means to bring the thermal head into and out of contact with the platen by the first drive transmitting means, and the second drive transmitting means. An operation of transmitting a drive from the motor to the paper transport means to transport the paper between the thermal head and the platen, and a drive from the motor to the ribbon transport means to transfer the drive between the thermal head and the paper by the third drive transmission means. The operation of transporting the ink ribbon is performed by a single motor.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the thermal printer according to the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the overall configuration of a thermal printer according to this embodiment. In the figure, the printing unit is composed of the platen 10 and the thermal head 6, and the paper 22 and the ink ribbon 23 are conveyed between the platen 10 and the thermal head 6. The thermal head 6 is provided with a large number of heating elements in the main scanning direction, selectively generates heat according to print data, and transfers the ink of the ink ribbon 23 onto the paper 22.

The paper 22 is wound around a reel 24,
It is taken out by rotation of the platen 10 and cut by the cutter 21 after printing. On the other hand, the ink ribbon 23 is wound around the supply reel 25 and, like the paper 22, the platen 1
When the printing is completed, the take-up reel 2
Take up to 6. The ink ribbon 23 is the supply reel 2
5, the take-up reel 26, and each guide roller 27 are made into a cassette and can be attached to and detached from the apparatus main body.

FIG. 2 is a diagram showing a configuration of a change gear group 2 for switching up and down operations of the thermal head 6, that is, the contact / separation operation of the thermal head 6 and the platen 10 and the conveyance of the paper. . Change gear group 2
In the configuration, the relay gear 2a that transmits power from the motor gear 1 to which a motor (not shown) is connected, the down gear 2b and the up gear 2c connected to the relay gear 2a, and the relay gear 2a by connecting these three gears are connected. Bracket 2d mounted so that it can rotate freely on the same axis as
It is composed of a spring 2e forming a clutch.

In the above structure, when the motor gear 1 rotates in the normal direction, that is, in the direction F (clockwise) of FIG. 2,
The relay gear 2a rotates in the counterclockwise direction opposite to F. At the same time, the down gear 2b also tries to rotate, but the spring 2e causes the bracket 2d and the down gear 2b to rotate.
The frictional force generated during the rotation prevents rotation unless the torque exceeds a certain value. However, since the bracket 2d can freely rotate on the same rotation shaft as the relay gear 2a, the action / reaction of the spring 2e causes the entire change gear group 2 to rotate leftward, that is, F ', in accordance with the rotation of the relay gear 2a. Rotate in the direction of.

On the other hand, when the motor gear 1 rotates in the reverse direction, that is, in the direction of R (counterclockwise), the same action is exerted, and the action / reaction of the spring 2e causes the entire change gear group 2 to move in accordance with the rotation of the relay gear 2a. Rotates in the direction of R '.

Next, a series of operations from the head-up state (initial state) of the thermal head 6 to head-down, printing, and further head-up will be described with reference to FIGS.

FIG. 4 is a view showing a state in which the thermal head 6 is completely separated from the platen 10. This position is the head-up completion position and the initial state. From this state, when the motor gear 1 rotates in the normal direction, that is, in the F direction of FIG. 5,
As described with reference to FIG. 2, the action / reaction of the spring 2e causes the entire change gear group 2 to rotate counterclockwise, that is, to rotate in the F'direction in FIG.
The down gear 2b meshes with. The bracket 2d of the change gear group 2 cannot rotate counterclockwise at this point, and the down gear 2b starts rotating clockwise against the spring force of the spring 2e. Down gear 2b and cam gear 3
Are engaged with each other by receiving a pressing force at this point, and the cam gear 3 rotates counterclockwise. As shown in the cam diagram of FIG. 3, the cam groove of the cam gear 3 moves the cam shaft of the head arm 4a from the inside to the outside in the counterclockwise direction. Therefore, the head arm 4 starts to move due to the rotation of the cam gear 3 and rotates counterclockwise around the arm shaft 4 ′, and the thermal head 6 approaches the platen 10.

When the motor is continued to rotate, the thermal head 6 eventually hits the platen 10, and a predetermined head pressing load is applied by the spring mounted between the head arm 4 and the head fixing base 5. As shown in the figure, the cam gear 3 has a portion where teeth are partially absent, that is, the groove 3
The cam gear 3 rotates until the down gear 2b of the change gear group 2 falls into the groove 3a of the change gear group 2.

FIG. 6 shows the down gear 2b of the change gear group 2.
Indicates that the up gear 2c is engaged with the gear 7, that is, the head down is completed and printing is being performed. At this point, the rotation of the cam gear 3 is stopped, the gear is changed, and the up gear 2c moves to the bracket 2
The rotation of d causes the gear 7 to mesh with the gear 7, and the power is transmitted to the gear 7, the gear 8 and the platen gear 9 to rotate the platen 10 counterclockwise. The ink ribbon 23 and the paper 22 are sandwiched between the platen 10 and the thermal head 6, and the ink ribbon 23 and the paper 22 can be fed and printed by rotating the platen 10.

At this time, the ink ribbon 23 that has been printed (transferred) needs to be peeled off from the paper 22 and wound up. Therefore, the platen gear 9 is meshed with the gear 11, and the power is transmitted in the order of the gear 12 and the clutch gear 13. The clutch gear 13 is
The ribbon winding core 26 is rotated through the slip clutch. The gear ratio at this time is set so that it can be wound at a speed higher than the paper feeding speed, and the speed difference is absorbed by the slip clutch so that tension is always applied to the ink ribbon 23. Therefore, the ink ribbon 23 sent out by the platen 10 together with the paper 22 is immediately wound up.

FIG. 7 is a view showing a state where the thermal head 6 is separated from the platen 10 by rotating the motor in the reverse direction, that is, by rotating the motor in the direction of R in FIG. That is, when the reverse rotation of the motor is started,
As described with reference to FIG. 2, the action / reaction of the spring 2e causes the entire change gear group 2 to rotate clockwise, that is, to rotate in the R'direction in FIG. 2, and the up gear 2c is separated from the gear 7 from the state of FIG. , The cam gear 3 bites. When the motor further rotates in the reverse direction, the cam gear 3 rotates clockwise in synchronization with the change gear group 2. When the cam gear 3 is rotated to the position shown in FIG. 4, the head arm 4 is also completely headed up, the up gear 2c falls into the groove 3b of the cam gear 3, the power is not transmitted to the cam gear 3, and the cam gear 3 is completely stopped. .

As described above, in this embodiment, the thermal head 6 having a plurality of heating elements arranged in an array in the main scanning direction, and the platen 1 arranged to face the thermal head 6.
0, a head arm 4 as a contacting / separating means for contacting / separating the thermal head 6 with respect to the platen 10, gears 7, 8 as a sheet conveying means for conveying a sheet between the thermal head 6 and the platen 10, a platen gear 9, and a platen. 10 and
In a thermal printer having a thermal head 6 and a ribbon carrying means 26 for carrying the ink ribbon 23 between the paper 22, a relay gear 2a, a down gear 2b, as first drive transmitting means for transmitting drive from the motor to the head arm 4. A cam gear 3, a relay gear 2a and an up gear 2c as second drive transmission means for transmitting the drive from the motor to the gears 7, 8, the platen gear 9, and the platen 10.
The gears 11 and 12 and the clutch gear 13 as the third drive transmission means for transmitting the drive from the motor to the ribbon conveying means 26 are provided, and the single motor allows the thermal head 6 and the platen 10 to be brought into and out of contact with each other and the sheet. And the ink ribbon is further conveyed.

[0019]

As described in detail above, the thermal printer of the present invention can carry out the paper feeding, the thermal head up / down operation, and the ink ribbon feeding by one motor, and therefore the number of parts can be reduced. Therefore, the size and weight of the device can be reduced and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of a thermal printer according to an embodiment.

FIG. 2 is a diagram showing a configuration of a change gear group.

FIG. 3 is a cam diagram showing how the cam shaft of the head arm moves.

FIG. 4 is a diagram showing a head-up completion state in a series of operations of the thermal head.

FIG. 5 is a diagram showing a head-down state in a series of operations of the thermal head.

FIG. 6 is a diagram showing a head-down completion state in a series of operations of the thermal head.

FIG. 7 is a diagram showing a state during head-up in a series of operations of the thermal head.

[Explanation of symbols]

2 ... Change gear group, 4 ... Head arm, 6 ... Thermal head, 7, 8, 11, 12 ... Gear, 9 ... Platen gear, 10 ... Platen, 13 ... Clutch gear, 22 ... Paper, 23 ... Ink ribbon, 25 ... Ribbon supply core, 26
… Ribbon winding core.

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[Procedure amendment]

[Submission date] February 14, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

On the other hand, when the motor gear 1 rotates in the reverse direction, that is, in the direction of R (counterclockwise), the same action is exerted, and the action / reaction of the spring 2e causes the entire change gear group 2 to move in accordance with the rotation of the relay gear 2a. Rotates in the R'direction. When a small torque motor is used, the change gear group is composed of two stages, a small diameter relay gear 2a 'and a large diameter relay gear 2a "that mesh with the motor gear 1', as shown by 2'in FIG. If so, the reduction ratio can be increased and a sufficient drive torque can be obtained.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] Figure 8

[Correction method] Added

[Correction content]

FIG. 8 is a diagram showing another configuration of a change gear group.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] Explanation of code

[Correction method] Change

[Correction content]

[Explanation of Codes] 2, 2 '... Change gear group, 4 ... Head arm, 6 ... Thermal head, 7, 8, 11, 12 ... Gear, 9 ... Platen gear, 10 ... Platen, 13 ... Clutch gear, 22 ...
Paper, 23 ... Ink ribbon, 25 ... Ribbon supply core, 2
6 ... Ribbon winding core.

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Correction target item name] Figure 8

[Correction method] Added

[Correction content]

[Figure 8]

Claims (1)

[Claims] 1. A thermal head in which a plurality of heating elements are arranged in an array in the main scanning direction, a platen disposed to face the thermal head, and a contacting / separating unit for contacting / separating the thermal head with respect to the platen. A thermal printer comprising: a sheet transporting unit that transports a sheet between the thermal head and the platen; and a ribbon transporting unit that transports an ink ribbon between the thermal head and the sheet, a motor, and the contacting / separating unit from the motor. Drive transmission means for transmitting drive to the sheet conveyance means, second drive transmission means for transmitting drive from the motor to the sheet conveying means, and third drive transmission for transmitting drive from the motor to the ribbon conveying means. And a means for moving the thermal head and the platen to and from each other, transporting the paper and transporting the ink ribbon by the single motor. Thermal printer characterized by Ukoto.