JPH07323651A - Thermal transfer printer - Google Patents

Abstract

PURPOSE:To prevent the lowering of printing quality caused by the fluctuations of torque at the start tide of feed due to the winding diameter change of an ink ribbon in a thermal transfer printer transferring the ink of the ink ribbon to printing paper by a thermal head to print an image. CONSTITUTION:A winding diameter detection means detecting the winding diameter of an ink ribbon according to the measuring result of the rotary encoder 34 connected to a ribbon feed mechanism 22 is provided and a winding diameter memory means storing the winding diameter of the ink ribbon is provided as an RAM 27 and a taking-up adjusting means regulating the electromotive power of the ribbon feed mechanism 22 according to the winding diameter stored in the winding diameter memory means when the driving start of the ribbon feed mechanism 22 is detected by a start detection means is provided and the taking-up torque at the start time of the taking-up operation of the ribbon feed mechanism 22 is corrected constant corresponding to the successively changing winding diameter of the ink ribbon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer printer for transferring an ink of an ink ribbon to a printing paper by a thermal head to print an image.

[0002]

2. Description of the Related Art Generally, a thermal transfer printer such as a label printer is equipped with a thermal head in which heating elements facing a platen are arranged in series in a main scanning direction. A ribbon transport mechanism which is inserted into a gap between the heating element and the platen and sequentially winds is formed by a winding roller and a drive motor. Furthermore, the paper transport mechanism that sequentially transports the printing paper that contacts the heating element via the ink ribbon in the sub-scanning direction is formed by the platen roller and the drive motor. The power supply means for supplying the driving power is composed of a power supply circuit connected to a commercial power supply.

In the thermal transfer printer as described above, the heating elements of the thermal head are selectively driven in synchronization with the transportation of the printing paper by the paper transportation mechanism and the transportation of the ink ribbon by the ribbon transportation mechanism. The ink of the ink ribbon is selectively transferred to printing paper to print a dot matrix image. In such a thermal transfer printer, the ink ribbon and the printing paper are conveyed at a constant speed, but it is necessary to quickly accelerate the stopped ink ribbon and the printing paper to a specified speed at the start of driving. . Therefore, the drive power supplied by the power supply means of such a thermal transfer printer to the ribbon transport mechanism or the like is set to be higher than the steady power in the normal operation and the start power for starting the drive.

In such a thermal transfer printer, it is not preferable to carry the ink ribbon when carrying the printing paper without executing image printing.
In such a case, there is also a thermal transfer printer having a ribbon save function that conveys only the printing paper without conveying the ink ribbon by separating the thermal head from the platen. Therefore, even when such a ribbon save is executed, the drive of the ribbon transport mechanism is temporarily interrupted, and the starting power is supplied from the power supply means when the drive is restarted.

[0005]

In the thermal transfer printer as described above, the ink of the ink ribbon sequentially transported by the ribbon transport mechanism is transferred to the printing paper sequentially transported by the paper transport mechanism by the heating element of the thermal head. It is designed to print images.

The ribbon transfer mechanism as described above is
Since the drive torque generated by the drive motor is always constant at the start of the printing operation, the conveyance torque of the ink ribbon fluctuates from the design value, which may impair the print quality.

Generally, the drive torque of the ribbon transport mechanism is set so that it does not become insufficient even if the winding diameter of the wound ink ribbon increases. The print quality is significantly degraded.

[0008]

A thermal head having a heating element facing a platen connected in the main scanning direction is provided, and an ink ribbon wound in advance is inserted into a gap between the heating element of the thermal head and the platen. And a ribbon transport mechanism for sequentially winding the sheet, and a sheet transport mechanism for sequentially transporting the print paper in contact with the heating elements of the thermal head via the ink ribbon in the sub-scanning direction. In a thermal transfer printer provided with an electric power supply means for supplying electric power, a rotary encoder is connected to a rotating portion of the ribbon transfer mechanism, and the ink ribbon wound by the ribbon transfer mechanism is wound according to a measurement result of the rotary encoder. A winding diameter detecting means for detecting the diameter is provided, and the winding diameter of the ink ribbon detected by the winding diameter detecting means is stored. Winding diameter storage means is provided, and start detection means for detecting drive start of the ribbon transport mechanism is provided. When the start detection means detects drive start, the ribbon transport mechanism is in accordance with the winding diameter stored in the roll diameter storage means. In addition, a winding adjusting means for adjusting the starting power supplied by the power supply means is provided.

[0009]

Since the winding diameter detecting means detects the winding diameter of the ink ribbon according to the measurement result of the rotary encoder connected to the rotating portion of the ribbon transport mechanism, and the winding diameter storing means stores the winding diameter of the ink ribbon. When the start detection means detects the start of driving of the transport mechanism, the winding adjustment means adjusts the starting power supplied by the power supply means to the ribbon transport mechanism in accordance with the winding diameter stored in the winding diameter storage means. The winding torque at the start of the winding operation of the ribbon transport mechanism is corrected to be constant corresponding to the winding diameter of the ribbon.

[0010]

An embodiment of the present invention will be described below with reference to the drawings. It should be noted that the directions such as front and rear and up and down in the present embodiment are defined for convenience in order to simplify the description, and this does not limit the actual installation or use direction of the device.

First, in the label printer 1 which is the thermal transfer printer exemplified in this embodiment, mechanically, as illustrated in FIG. 2, a large number of labels 3 can be peeled off on the surface of a mount 2 made of continuous paper. Label sheet 4 attached at regular intervals
Is set on the sheet transport mechanism 5 which is a sheet transport mechanism. The sheet transport mechanism 5 is configured to include the supply roller 6, the sheet guides 7 and 8 and the guide roller 9 here.
And a platen roller 11 and the like.

Further, in the label printer 1, a label peeling member 12 for peeling the label 3 by bending the mount 2 of the label sheet 4 at a steep angle is provided in front of the platen roller 11. Further, a mount take-up mechanism 13 that winds up the mount 2 on which the label 3 of the label sheet 4 is peeled is provided below the label peeling member 12, and the mount take-up mechanism 13 is
Here, the mount guides 14 and 15 and the winding roller 16 are included.

Further, in the label printer 1, a thermal head 17 is pressed against the platen roller 11 by a head pressing release mechanism (not shown) so that the thermal head 17 and the platen roller 11 can be separated from each other.
The label sheet 4 passes through the gap between The head pressing release mechanism includes the thermal head 17 that is biased by the platen roller 11 by a leaf spring or the like.
Is a mechanism that separates the thermal head 17 from the platen against the biasing force, presses the other end against the platen roller 11 with one end of the thermal head 17 as a rotating shaft, and connects a solenoid (not shown) to the other end. The thermal head 17 is pulled up by (1).

In this label printer 1, the supply roller 1
A ribbon transport mechanism 22 for sequentially transporting the ink ribbon 21 wound in a roll shape is configured by the 8, the winding roller 19, the guide frame 20, and the like, and the ink ribbon 21 transported by the ribbon transport mechanism 22. Is supplied from the supply roller 18 and passes through a gap between the thermal head 17 and the platen roller 11 in a state of being overlapped with the label sheet 4 and is wound by the winding roller 19.

Behind the thermal head 17, a transmissive photosensor 23 for detecting the ink ribbon 21.
A photo sensor 24, which is a combination of a transmissive type and a reflective type, which detects the label sheet 4, is provided in parallel behind the thermal head 17 and in front of the feed roller 9.

Here, in the label printer 1, various kinds of data such as a control program are fixed to a CPU (Central Processing Unit) 25 which executes various kinds of data processing, as shown in FIG. ROM (R
ead only memory) 26, RAM (Random Access Memory) 2 for temporarily storing various data such as print data in an updatable manner
7. I / F (Interface) 28 for receiving various data such as print data from a host computer (not shown), reference clock 29 for constantly outputting a clock pulse, the thermal head 17, the photo sensors 23, 24, the A pulse motor 30 that rotationally drives the supply roller 6 and the platen roller 11 of the sheet conveying mechanism 5, the mount paper winding mechanism 13
Of a pulse motor 31 for rotating and driving the take-up roller 16 and a photosensor 3 of a rotary encoder (not shown) directly connected to a rotary shaft that is a rotating portion of the pulse motor 31.
2. A DC (Direct Current) motor 33 for rotatably driving the winding roller 19 of the ribbon transport mechanism 22, and a photosensor 34 of a rotary encoder (not shown) directly connected to a rotating shaft which is a rotating portion of the DC motor 33. The system has a structure in which a DC motor 35 for rotating the supply roller 18 of the ribbon transport mechanism 22 and the like are connected by a system bus 36.

Furthermore, in the label printer 1, the thermal head 17, the pulse motor 30 of the sheet conveying mechanism 5, the pulse motor 31 of the mount winding mechanism 13 and the DC motors 33 and 35 of the ribbon conveying mechanism 22 are used. Power supply means for supplying drive power is provided as a power supply circuit (not shown) connected to a commercial power supply (not shown).

The label printer 1 includes the ROM 26.
And the CPU according to the data stored in the RAM 27, etc.
25 executes various data processing to print an image on the label 3. Further, a winding diameter detecting means for detecting the winding diameter of the ink ribbon 21 according to the measurement result of the photo sensor 34 of the ribbon transport mechanism 22 is provided, and the winding diameter of the ink ribbon 21 detected by the winding diameter detecting means. A winding diameter storage means for storing is set in a predetermined area of the RAM 27. A start detecting means for detecting the drive start of the ribbon transport mechanism 22 is provided, and when the start detect means detects the drive start, the DC motor 33 of the ribbon transport mechanism 22 according to the winding diameter stored in the RAM 27. A winding adjustment means for adjusting the starting power supplied by the power supply circuit is provided.

More specifically, in the label printer 1, an arithmetic expression for calculating the winding diameter of the ink ribbon 21 according to the measurement result of the photo sensor 34 in a normal printing operation is preset in the RAM 27. R
The CPU 25 calculates the winding diameter of the ink ribbon 21 in accordance with the arithmetic expression of AM27. Then, a table defining the relationship between the winding diameter of the ink ribbon 21 and the starting voltage which is the starting power of the DC motor 33 in the normal printing operation is preset in the RAM 27, and according to the table of the RAM 27, the table is set. C
The PU 25 adjusts the starting voltage supplied to the DC motor 33.

Since the label printer 1 has a ribbon save function, the thermal head 17 is separated from the platen roller 11 by the head pressing release mechanism to stop the rotational driving of the DC motors 33 and 35. Then, the ribbon transport mechanism 22 causes the ink ribbon 21 to move.
Only the label sheet 4 is transported by the sheet transport mechanism 5 without transporting the label sheet 4.

In such a structure, the label printer 1 has the thermal head 17 in synchronization with the conveyance of the label sheet 4 by the platen roller 11 of the sheet conveyance mechanism 5 and the conveyance of the ink ribbon 21 by the ribbon conveyance mechanism 22. The heating element (not shown) is selectively driven to generate heat according to the print data, and the ink of the ink ribbon 21 is selectively transferred to the label 3, so that the image of the dot matrix is printed on the label 3. .

In the label printer 1, the label sheet 4 that has passed the position of the thermal head 17 is bent at a sharp angle by the label peeling member 12 to peel the label 3 from the mount 2, and the front half of the label 3 is removed. It is designed to stop while protruding to the outside. Therefore, this label 3
When the user takes out the label, the special photo sensor (not shown) detects that the label 3 is taken out, and restarts various operations as described above. Further, since the mount 2 having the label 3 peeled off in this manner is sequentially wound by the mount winding mechanism 13, it is possible to prevent unnecessary mounts from being discharged to the outside of the apparatus and clutter the surroundings.

Here, in the label printer 1, when the winding diameter of the ink ribbon 21 wound by the winding roller 16 by the ribbon transport mechanism 22 changes as described above, this winding diameter is detected and stored in the RAM 27. When the next winding operation of the ribbon transport mechanism 22 is started, the DC motors 33, 35
The drive torque of is adjusted.

More specifically, when the winding diameter of the ink ribbon 21 changes, the ink ribbon 21 is driven by a steady voltage during the printing operation.
The rotation speeds of the C motors 33 and 35 change according to the winding diameter of the ink ribbon 21. Therefore, this DC motor 33, 3
The rotation speed of No. 5 is measured by the photo sensor 34, and the CPU 25 determines the winding diameter “φ” of the ink ribbon 21 according to the measurement result.
And the calculated winding diameter of the ink ribbon 21 is RA
It is stored in M27.

Then, the label printer 1 detects the start of driving of the ribbon transport mechanism 22 and reads the winding diameter stored in the RAM 27 when starting the printing operation which has ended in the above-described state, and this winding is performed. The starting voltage “V” supplied from the driving power supply to the DC motor 33 is adjusted under the control of the CPU 25 according to the diameter and the table of the RAM 27. By doing this, the ribbon transport mechanism 2 is started at the start of the winding operation.
Since the winding torque of No. 2 can be corrected to be constant, it is possible to prevent the print quality from being deteriorated by the thermal head 17.

Further, in the label printer 1, the label save function may allow the sheet carrying mechanism 5 to carry only the label sheet 4 without carrying the ink ribbon 21 by the ribbon carrying mechanism 22. Therefore, as illustrated in FIG. 4, even when such a ribbon save is executed, the photosensor 34 measures the rotational speed of the DC motors 33 and 35 which are driven by a constant voltage when the printing operation is executed, and the ink ribbon is measured. The winding diameter “φ” of 21 is calculated, and the calculated winding diameter of the ink ribbon 21 is stored in the RAM during the ribbon save operation.
It is stored in 27. Then, when the printing operation for completing the ribbon save is restarted, the winding diameter is read from the RAM 27 and the starting voltage “V” supplied from the driving power supply to the DC motors 33 and 35 is adjusted, so that the winding operation of the ribbon transport mechanism 22 is performed. The torque is corrected to a constant value to prevent deterioration of print quality.

In the label printer 1 of this embodiment,
The drive power of the ribbon transport mechanism 22 is set to the DC motors 33, 35.
However, the present invention is not limited to the above embodiment, and for example, such adjustment of the driving power can be performed by the amount of current.

Further, in the label printer 1 of this embodiment,
Although the calculation of the winding diameter of the ink ribbon 21 according to the measurement result of the photo sensor 34 is illustrated, it is also possible to detect the relation between the measurement result and the winding diameter according to a preset table. Similarly, the ink ribbon 21
Although the driving power of the DC motors 33 and 35 is detected according to the table according to the winding diameter of the above, it can be calculated according to a preset arithmetic expression.

[0029]

As described above, the present invention is provided with a thermal head in which heating elements opposed to a platen are arranged in series in the main scanning direction, and a pre-wound ink ribbon is provided between the heating elements of the thermal head and the platen. Is provided with a ribbon transport mechanism that sequentially winds through the gap of the thermal head, and a paper transport mechanism that sequentially transports the printing paper in contact with the heating element of the thermal head via the ink ribbon in the sub-scanning direction is provided to the ribbon transport mechanism. In a thermal transfer printer provided with power supply means for supplying start-up power and steady power, a rotary encoder is connected to the rotating part of the ribbon transport mechanism,
A winding diameter storage unit is provided for detecting the winding diameter of the ink ribbon wound by the ribbon transport mechanism according to the measurement result of the rotary encoder, and the winding diameter storage unit stores the winding diameter of the ink ribbon detected by the winding diameter detection unit. Means is provided, start detection means for detecting the drive start of the ribbon transport mechanism is provided, and when the start detection means detects the drive start, the power is supplied to the ribbon transport mechanism according to the winding diameter stored in the winding diameter storage means. By providing the winding adjustment means for adjusting the starting power supplied by the means, the winding torque at the start of the winding operation of the ribbon transport mechanism is constantly corrected in accordance with the winding diameter of the ink ribbon which changes in sequence. Therefore, it is possible to prevent the print quality from deteriorating due to fluctuations in the ink ribbon transport torque.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a circuit structure of a thermal transfer printer according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional side view illustrating an internal structure.

FIG. 3 is a time chart exemplifying the relationship between the measurement result of the photosensor of the rotary encoder at the time of executing the normal printing operation and the drive voltage of the pulse motor of the mount take-up mechanism at the start of the winding operation.

FIG. 4 is a time chart exemplifying the relationship between the measurement result of the photo sensor of the rotary encoder at the time of executing the ribbon save and the drive voltage of the pulse motor of the mount take-up mechanism at the start of the take-up operation.

[Explanation of symbols]

 1 Thermal Transfer Printer 5 Paper Transfer Mechanism 17 Thermal Head 21 Ink Ribbon 22 Ribbon Transfer Mechanism 27 Roll Diameter Storage Means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B41J 33/32

Claims (1)

[Claims] 1. A thermal head comprising heating elements facing a platen connected in the main scanning direction is provided, and a pre-wound ink ribbon is inserted into a gap between the heating elements of the thermal head and the platen and sequentially wound. A ribbon transport mechanism is provided, and a paper transport mechanism that sequentially transports the printing paper in contact with the heating element of the thermal head via the ink ribbon in the sub-scanning direction is provided, and the ribbon transport mechanism is supplied with starting power and steady power. In a thermal transfer printer provided with a power supply means for connecting a rotary encoder to a rotating part of the ribbon transport mechanism, and detecting a winding diameter of the ink ribbon wound by the ribbon transport mechanism according to a measurement result of the rotary encoder. Winding diameter storage means for providing a winding diameter detecting means and storing the winding diameter of the ink ribbon detected by the winding diameter detecting means Is provided, and start detection means for detecting the drive start of the ribbon transport mechanism is provided. When the start detection means detects the drive start, the power supply means for supplying power to the ribbon transport mechanism according to the winding diameter stored in the winding diameter storage means. A thermal transfer printer, characterized in that it is provided with a winding adjustment means for adjusting the starting power supplied by the printer.