JPH0671918A - Driving method for thermal transfer printer - Google Patents

Abstract

PURPOSE:To print letters uniformly with good quality or a paper of the rough surface by uniformly heating an intermediate transfer body in a halftone transfer method. CONSTITUTION:When an intermediate transfer body is preheated by a heating means 2 before printing, a thermal head 3 and a pressure roller 8 are separated from the intermediate transfer body, so that the intermediate transfer body is rotated idly. The intermediate transfer body is heated uniformly, so that an ink ribbon 6 can be detached from the body when it is hot. Accordingly, printing with good quality is achieved.

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 the ink of an ink ribbon to a sheet by heat of a thermal head for printing, and more particularly to transferring the ink of the ink ribbon to an intermediate transfer member by the thermal head. The present invention relates to an intermediate transfer thermal transfer printer that forms a primary recording image by re-transferring the primary recording image onto a sheet, and particularly to a driving method thereof.

[0002]

2. Description of the Related Art Conventionally, many thermal transfer printers have been used which perform printing in a state where a thermal head is pressed against a platen via a paper and an ink ribbon. In such a thermal transfer printer, a bond paper or the like is used. When printing on a paper having a rough surface, it is necessary to press the thermal head with a strong pressing force, but the pressing force of the thermal head is limited due to its precise structure. Therefore, the heat of the thermal head partially melts the ink of the ink ribbon and transfers it to the intermediate transfer member to form a primary recording image on the intermediate transfer member. 2. Description of the Related Art An intermediate transfer type thermal transfer printer is used in which an intermediate transfer member is transferred to a sheet by a pressure roller that presses the intermediate transfer body against the sheet with a pressing force.

FIG. 3 shows an outline of such a conventional intermediate transfer type thermal transfer printer.
A cylindrical intermediate transfer roller 1 that constitutes an intermediate transfer member is rotatably arranged, and a heater 2 for heating the intermediate transfer roller 1 to a predetermined temperature is provided inside the intermediate transfer roller 1. It is built in. A thermal head 3 is arranged near the intermediate transfer roller 1. The thermal head 3 is provided with a plurality of heating elements 4 arranged in a straight line so as to face the central portion of the intermediate transfer roller 1. On both sides of the thermal head 3, ink is applied to the bobbins 5. A pair of ribbon rolls 7 formed by winding a ribbon 6 and guiding the ink ribbon 6 between the intermediate transfer roller 1 and the thermal head 3 in a substantially linear manner.
A and 7B are arranged. Of these, ribbon roll 7
A is the supply side, and the ribbon roll 7B is the winding side. Further, a pressure roller 8 which is pressed against the intermediate transfer roller 1 with a strong pressing force is rotatably arranged at a position symmetrical in the diameter direction of the intermediate transfer roller 1 with respect to the thermal head 3. A predetermined paper 9 such as plain paper is inserted between the intermediate transfer roller 1 and the pressure roller 8 and the intermediate transfer roller 1 is rotated to drive the paper 9 to the intermediate transfer roller 1 and the pressure roller 8. It is sandwiched between and and conveyed in the direction opposite to the running direction of the ink ribbon 6.

According to the above-mentioned conventional thermal transfer printer,
A sheet of paper 9 is placed between the intermediate transfer roller 1 and the pressure roller 8.
When the pressure roller 8 is pressed against the intermediate transfer roller 1 with a strong pressing force, the thermal head 3 is pressed against the intermediate transfer roller 1, and the intermediate transfer roller 1 is driven to rotate in this state. Ribbon roll 7 on the winding side while carrying 9
While winding the ink ribbon 6 at a predetermined speed by B, the thermal head 3 is driven based on desired print data. As a result, the heating element 4 of the thermal head 3 generates heat and the ink of the ink ribbon 6 is partially melted and transferred to the surface of the intermediate transfer roller 1 to form a primary recording image. At this time, the primary recording image formed on the surface of the intermediate transfer roller 1 has only to be held on the intermediate transfer roller 1, and since the surface of the intermediate transfer roller is smooth, the thermal head 3 is moved to the intermediate transfer roller 1. It is not necessary to press it with such a strong pressure.

Then, the heater 2 of the intermediate transfer roller 1
While the ink transferred to the intermediate transfer roller 1 is heated to a constant temperature to cause the ink to have a certain degree of viscosity, the primary recording image of the intermediate transfer roller 1 is applied to the sheet 9 by the pressure contact force of the pressure roller 8. Reprinting can be performed and desired printing can be performed on the sheet 9. As a result, the pressure roller 8 re-transfers to the paper 9 with a strong pressure contact force, so that printing can be performed even on the paper 9 having a rough surface such as bond paper.

[0006]

By the way, in the thermal transfer printer of the intermediate transfer system having the above-mentioned structure, the heating element 4 of the thermal head 3 generates heat to partially melt the ink of the ink ribbon 6, and the intermediate transfer roller The peeling of the ink ribbon 6 from the intermediate transfer roller 1 when the primary recording image was formed by being transferred to the surface of No. 1 was supposed to be after the ink melted by the heat generated by the heating element 4 was cooled. Peeling of the ink ribbon at such a timing is referred to as cold peeling, and is a peeling method that opposes hot peeling in which peeling is performed when the ink is still in a molten state.

For the peeling of the ink ribbon 6 in the cold state, a wax type ink has been used in order to improve the printing quality. However, since this wax-based ink does not form a film even if it is melted by the heat generated by the heating element 4, voids may be generated and good quality printing can be performed on the paper 9 having a rough surface. There wasn't. In addition, ink may remain on the intermediate transfer roller 1.

Therefore, the paper 9 having the above-mentioned rough surface is used.
It has been found that the ink itself needs to be of a resin type capable of forming a film state by the heat generation of the heating element of the thermal head in order to uniformly adhere the ink onto the surface.

Due to its characteristics, the resin-based ink is transferred to the print medium (intermediate transfer roller 1) only when the ink of the ink ribbon 6 is melted by the heat energy generated from the heating element 4 of the thermal head 3. Is possible. On the other hand, according to the experiments conducted so far, the time during which the ink is maintained in the molten state is 5 msec which is very short from the time when the heat energy from the heating element 4 is obtained. However, it has been difficult to perform thermal peeling with an ink ribbon having a resin-based ink.

Further, it is necessary to heat the intermediate transfer roller 1 for peeling at the time of heat, but it was difficult to heat the outer peripheral surface of the intermediate transfer roller 1 to a uniform temperature.

In view of the above-mentioned point, the present invention drives a thermal transfer printer capable of uniformly heating an intermediate transfer member in an intermediate transfer system to print on a paper having a rough surface. The purpose is to provide a method.

[0012]

In order to achieve the above-mentioned object, a method of driving a thermal transfer printer according to the present invention is heated by a thermal head which partially melts ink of an ink ribbon according to print data and a heating means. An ink ribbon is interposed between the intermediate transfer member and a pressure roller that is pressed against the intermediate transfer member, and the thermal head and the pressure roller can be contacted and separated from the intermediate transfer member. In the thermal transfer printer, when the intermediate transfer body is preheated by the heating means before printing, the thermal head and the pressure roller are separated from the intermediate transfer body to idle the intermediate transfer body.

[0013]

According to the present invention, when the intermediate transfer member is preheated by the heating means, the intermediate transfer member is preheated while idling, so that the intermediate transfer member is heated to a uniform temperature in its circumferential direction. As a result, the resin-based ink can be used to perform the peeling at the time of heat, so that good quality printing can be performed by uniformly depositing the ink on the paper having a rough surface.

[0014]

The present invention will be described below with reference to the embodiments shown in the drawings. It should be noted that the same or corresponding configurations as those of the conventional one described above are denoted by the same reference numerals in the drawings, and description thereof will be omitted.

1 and 2 show an embodiment of a thermal transfer printer for carrying out the driving method of the present invention.
As shown in detail in FIG. 2, the thermal head 3 in this embodiment has a flat insulating substrate 10 formed of a material such as ceramic. This insulating substrate 10
A glaze layer 11 made of a material such as glass and having a heat storage function is laminated on one end of the. The upper surface of the glaze layer 11 is formed in an arc shape so that the top portion thereof extends in the alignment direction of the heating elements 4. This glaze layer 11
A plurality of heating elements 4 are linearly arranged on the top of the. Further, a common electrode (not shown) and an individual electrode (not shown) for supplying power to the heating element 4 are connected to each heating element 4, and in the present embodiment, the common electrode is provided from the end side of the insulating substrate 10. It is connected to each heating element 4.

The length of the common electrode from the end face 12 of the insulating substrate 10 to each heating element 4 is 0.9 mm or less. This size is extremely smaller than that of the conventional thermal head. As a result, in the thermal head 3 of this embodiment, each heating element 4 is located near the end face 12 of the insulating substrate 10, a so-called real edge. It is said to be of a type.

The thermal head 3 of the present embodiment having the above-described structure is arranged so that the end face 12 of the insulating substrate 10 is located downstream of the heating element 4 in the running direction of the ink ribbon 6. Moreover, the heating element 4 is movably arranged so that it can be brought into contact with and separated from the intermediate transfer roller 1.

Further, on the downstream side of the thermal head 3 in the running direction of the ink ribbon 6, a peeling pinch roller for immediately peeling the ink ribbon 6 at a portion passing through the heating element 4 from the intermediate transfer roller 1. A thermal head 3 is rotatably arranged on an extension of the insulating substrate 10 of the thermal head 3, and the ink ribbon 6 is placed along the outer peripheral surface of the pinch roller 13 on the side separated from the intermediate transfer roller 1. By running, the ink ribbon 6 at the portion passing through the heating element 4 can be immediately separated from the intermediate transfer roller 1.

Further, the pressure roller 8 which comes into pressure contact with the intermediate transfer roller 1 is movably arranged so as to be able to come into contact with and separate from the intermediate transfer roller 1.

Further, the heater 2 provided in the intermediate transfer roller 1 is constituted by a halogen lamp as an example so that the intermediate transfer roller 1 can be heated uniformly in its axial direction.

The other structure is the same as the above-mentioned conventional one.

Next, the operation of this embodiment having the above-mentioned structure will be described.

When the main switch of the thermal transfer printer is turned on for printing, the thermal head 3 and the pressure roller 8 are separated from the intermediate transfer roller 1 in this state as shown in FIG. At this time, the heater 2 as a heating means is turned on to preheat the intermediate transfer roller 1, and at this time, the intermediate transfer roller 1 is idly driven by the driving means (not shown). It is heated uniformly in the circumferential direction. In this way, the intermediate transfer roller 1 is preheated because a temperature of about 50 ° C. to 63 ° C. at which the melted state of the ink can be maintained on the outer peripheral surface of the intermediate transfer roller 1 in order to peel the ink ribbon 6 when heated. That is, it is necessary to heat to a temperature higher than the ambient temperature and lower than the melting point of the ink.

When the intermediate transfer roller 1 is preheated for a certain period of time as described above, the printing becomes possible. Therefore, when the sheet 9 is inserted between the intermediate transfer roller 1 and the pressure roller 8, the intermediate transfer roller 1
The pressure roller 8 is pressed against the intermediate transfer roller 1, the thermal head 3 is pressed against the intermediate transfer roller 1, and the intermediate transfer roller 1 is rotationally driven to convey the paper 9, and the ribbon roll 7B on the take-up side drives the ink ribbon. While winding 6 at a predetermined speed, the thermal head 3 is driven based on desired print data. As a result, the heating elements 4 of the thermal head 3 selectively generate heat to partially melt the ink of the ink ribbon 6 and transfer it to the surface of the intermediate transfer roller 1 to form a primary recording image.

By the way, the ink of the ink ribbon 6 in this embodiment is of resin type suitable for peeling at the time of heat, while the thermal head 3 in this embodiment is of the real edge type and the pinch roller 13 is used. By this action, the ink ribbon 6 at the portion passing through the heat generating element 4 is immediately separated from the intermediate transfer roller 1, and the intermediate transfer roller 1 is also heated by the heater 2 provided therein. The ink of the ink ribbon 6 in the portion melted by heat is transferred to the intermediate transfer roller 1 while it is still melted. Therefore, the ink of the ink ribbon 6 is transferred to the intermediate transfer roller 1 when it is in a film state due to melting, and the ink of the ink ribbon 6 is evenly attached to the primary recording image on the intermediate transfer roller 1. It is of good quality.

Next, the heater 2 of the intermediate transfer roller 1
While the ink transferred to the intermediate transfer roller 1 is heated so as to be in a semi-molten state by the ink to form a film of ink with a certain degree of viscosity, the pressure of the pressure roller 8 causes the primary transfer of the intermediate transfer roller 1. The recording image is retransferred to the sheet 9 to perform desired printing on the sheet 9. At this time, since the ink of the primary recording image is in a film state, the ink is evenly adhered to the printing on the sheet 9. It can be of good quality. As described above, in this embodiment, since the resin-based ink is used and the transfer is performed when the ink is in the form of a film due to heat, it is possible to always perform good quality printing. Moreover, since the preheating is performed while the intermediate transfer roller 1 is idling, the preheating time of the intermediate transfer roller 1 can be shortened.

The present invention is not limited to the above-mentioned embodiment, but can be variously modified if necessary. For example, in the above-described embodiment, the intermediate transfer roller is used as the intermediate transfer body, but it is also possible to use a belt or the like as the intermediate transfer body.

[0028]

As described above, according to the driving method of the thermal transfer printer of the present invention, it is possible to stably preheat the intermediate transfer member and perform the transfer when the ink is in the form of a film due to the heat. Therefore, it is possible to achieve an effect that good quality printing can be performed even on a paper having a rough surface.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a thermal transfer printer for carrying out a driving method of the present invention.

FIG. 2 is an enlarged view of a main part of FIG. 1 showing a state during preheating of an intermediate transfer roller.

FIG. 3 is a schematic configuration diagram showing a conventional thermal transfer printer.

[Explanation of symbols]

 1 Intermediate Transfer Roller 2 Heater 3 Thermal Head 4 Heating Element 6 Ink Ribbon 8 Pressure Roller 9 Paper 10 Insulating Substrate 11 Glaze Layer 12 End Face of Insulating Substrate 13 Pinch Roller

Claims (1)

[Claims] 1. An ink ribbon is interposed between a thermal head that partially melts ink of an ink ribbon according to print data and an intermediate transfer member that is heated by a heating unit, and is pressed against the intermediate transfer member. A thermal transfer printer in which the thermal head and the pressure roller are respectively brought into contact with and separated from the intermediate transfer body, the thermal head and the thermal head are preheated by the heating means before printing. A method of driving a thermal transfer printer, characterized in that the pressure rollers are separated from the intermediate transfer member so that the intermediate transfer member is idle.