JPH07329327A - Thermal transfer printer - Google Patents

Abstract

PURPOSE:To obtain a stable recording accuracy, and to reduce the size and the cost of the entire thermal transfer printer. CONSTITUTION:A thermal transfer printer comprises a thermal head 5 for partly melting the ink of an ink ribbon 4 by selectively generating heat from a heat generating element, an intermediate transfer unit 3 to be formed with a primarily recorded image by transferring the ink of the ribbon 4 melted by the heat generated from the head 5, and re-transfer means for re-transferring the image transferred to the unit 3 to record it as desired, wherein the unit 3 is formed on its surface of a material having a large coefficient of friction with respect to the ribbon 4.

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 in which ink of an ink ribbon is partially melted by heat of a thermal head and transferred to a sheet for recording. The present invention relates to an intermediate transfer thermal transfer printer that transfers a primary recording image onto a transfer body to form a primary recording image, and retransfers the primary recording image to a sheet to perform desired recording.

[0002]

2. Description of the Related Art Conventionally, a thermal transfer printer has been widely used in which a thermal head is pressed against a platen via a paper and an ink ribbon to perform recording. In such a thermal transfer printer, surface roughness of bond paper or the like is used. When recording on rough paper, it is necessary to press the thermal head against the paper on the platen 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 recording is performed by re-transferring onto a sheet that is pressed by a strong pressing force of a roller.

FIG. 3 shows a conventional intermediate transfer type thermal transfer printer of this type, in which a platen roller 21 having a cylindrical metal surface coated with a rubber material as an intermediate transfer member 20 is rotationally driven. The thermal head 22 is disposed freely near the platen roller 21.
Is provided. The thermal head 22 has a plurality of heating elements linearly arranged so as to face the central portion of the platen roller 21, and both sides of the thermal head 22 are wound around bobbins 23. The ink ribbon 24 is connected to the platen roller 21 and the thermal head 2.
A pair of ribbon rolls 2 which guides between the two in a substantially straight line
5 are provided. Further, a ribbon feed mechanism is arranged at an intermediate portion between the thermal head 22 and the ribbon roll 25a on the take-up side of the ink ribbon 24. The ribbon feed mechanism includes a pinch roller 26 and an ink ribbon 2
4 is configured by a ribbon guide shaft 27 for guiding the pinch roller 26 to be wound around the pinch roller 26 and a motor (not shown) for rotationally driving the pinch roller 26. By driving the pinch roller 26, the ink ribbon 24 is conveyed. The speed is controlled to be constant.

A pressure roller 28, which is brought into pressure contact with the platen roller 21 with a strong pressure contact force, is rotatably disposed at a position symmetrical to the thermal head 22 in the platen roller 21 in the diametrical direction. A predetermined paper 29 such as plain paper is inserted between the platen roller 21 and the pressure roller 28, and the platen roller 21 is rotationally driven to move the paper 29 between the platen roller 21 and the pressure roller 28. It is sandwiched between and conveyed in the direction opposite to the running direction of the ink ribbon 24.

In this thermal transfer printer, first, with the paper 29 inserted between the platen roller 21 and the pressure roller 28, the pressure roller 28 is pressed against the platen roller 21 with a strong pressing force, and in this state, the pinch roller 26 is pressed. To drive the ink ribbon 24
While the ink ribbon 24 is being conveyed at a constant speed and the bobbin 23 on the winding side having a slip mechanism is rotationally driven to wind up, each heating element of the thermal head 22 generates heat based on a desired recording signal. Let Then, the platen roller 21 is rotated to drive the paper 2
9 is conveyed, and the ink of the ink ribbon 24 is partially melted by the selective heat generation of each heating element of the thermal head 22 and transferred to the surface of the platen roller 21. The primary recording image thus formed on the surface of the intermediate transfer member 20 is retransferred to the conveyed paper 29 by the pressure contact force of the pressure roller 28 to obtain desired recording.

By the way, the pinch roller 26 is provided for the following purpose.

That is, regarding the conveyance of the ink ribbon 24, when it is attempted to convey the ink ribbon 24 by the rotational driving of the platen roller 21 that is in pressure contact with the ink ribbon 24, the adhesiveness of the intermediate transfer body 20 is the smoothness ( In terms of surface roughness) and hardness (JIS hardness), the thermal head 22 is used when a rubber material having a smoothness of Rmax of 50 μm or more and a hardness of 60 degrees or more is used.
When printing was performed with the head pressing force P of 100 to 300 g / cm ² , the ink ribbon 24 could not be satisfactorily conveyed because slip occurred between the platen roller 21 and the ink ribbon 24. When the ribbon ribbon 25a on the take-up side is driven by rotation,
Since the transport speed changes depending on the outer diameter of the winding-side ribbon roll 25a, uniform recording results cannot be expected. Therefore, in order to stably convey the ink ribbon 24 at a constant speed, a pinch roller 26 is provided as a means for controlling the conveyance speed of the ink ribbon 24.

Further, in view of the mechanical design of this type of printer, in order to prevent the slack of the ink ribbon being conveyed, the ink ribbon conveying speed (V ₁ ) by the pinch roller is the platen. It is set to be slightly higher than the conveyance speed (V ₀ ) of the ink ribbon by the roller.

[0009]

However, the writing accuracy is determined by the rotation speed of the platen roller 21, and even if the transport speed of the ink ribbon 24 is adjusted to the writing speed by calculation, the platen roller 21 and the pinch roller 21 are pinched. If the outer diameter of the roller 26 deviates even a little as part accuracy, the rotational speeds of the platen roller 21 and the pinch roller 26 are also slightly different, so that the transferred ink thickness cannot be made constant and a good recording result is obtained. I couldn't.

Further, the conveyance speed of the ink ribbon 24 is set to V ₁
Even if> V ₀ , the smoothness is Rma as described above.
Intermediate transfer member 20 having x of 50 μm or more and hardness of 60 degrees or more
In the above, a slip has occurred between the ink ribbon 24 and the platen roller 20, and as a result of the experiment, the friction coefficient of the material of the intermediate transfer member 20 is found to be
Although it depends on the rubber material on the surface of No. 1, it was found that the slip occurred when it was about 0.95 or less.

Further, since the parts related to the pinch roller 26 and the driving source are also required separately, the cost becomes high,
The thermal transfer printer could not be downsized.

Therefore, the present invention aims to provide a thermal transfer printer which overcomes the problems of the prior art described above, can obtain stable recording accuracy, and can realize the miniaturization of the entire apparatus and the reduction of cost. To aim.

[0013]

In order to achieve the above object, a thermal transfer printer according to claim 1 of the present invention is a thermal transfer printer which selectively heats a heating element to partially melt ink of an ink ribbon. A head and an intermediate transfer member on which a primary recording image is formed by transferring the ink of the ink ribbon melted by the heat generation of the thermal head,
In a thermal transfer printer having a retransfer means for retransferring the primary recording image transferred to the intermediate transfer member to a sheet to perform desired recording, the surface of the intermediate transfer member has a friction coefficient of 1 with the ink ribbon. It is characterized by being formed of a material of 0.0 or more.

According to a second aspect of the present invention, in the thermal transfer printer according to the first aspect, the surface of the intermediate transfer member is formed of silicone rubber.

[0015]

In the thermal transfer printer of the present invention, the ink ribbon is stably conveyed by the large frictional force between the ink ribbon and the intermediate transfer member, and the ink of the ink ribbon is melted and transferred by the heat generated by the thermal head. A primary recording image is formed on the intermediate transfer member, and the primary recording image transferred to the intermediate transfer member is retransferred to a sheet to perform desired recording.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a partial structural sectional view of a printer according to the first embodiment of the present invention.

In the thermal transfer printer of this embodiment, a cylindrical backup roller 1 is rotatably arranged, and inside the backup roller 1, the backup roller 1 is heated to a predetermined temperature. The heater 2 is built in. The backup roller 1 has a cylindrical metal surface coated with a rubber material (not shown) so that it can also function as a platen roller. Further, the backup roller 1 is in close contact with the surface of the rubber material of the backup roller 1. The intermediate transfer body 3 having the property is coated. A drive device (not shown) such as a motor is connected to the backup roller 1.

The thickness of the rubber material coated on the surface of the backup roller 1 is preferably about 1 mm to 2 mm, and the film thickness of the intermediate transfer member 3 is 10 μm to 5 mm.
Optimum is about 00 μm, preferably 50 μm to 2
It is obtained from the experimental data that it is 00 μm. The surface roughness of the intermediate transfer member 3 is 40 μm or less in Rmax, and the hardness is JIS 10 to 40 degrees.

A thermal head 5 is arranged near the backup roller 1. The thermal head 5 has a plurality of heating elements linearly arranged so as to face the central portion of the backup roller 1. On both sides of the thermal head 5, an ink ribbon wound around a bobbin 6 is provided. Between the backup roller 1 and the thermal head 5, there is provided a pair of ribbon rolls 7, 7 that guide the roller 4 in a substantially straight line. Further, a pressure roller 8 which is pressed against the backup roller 1 with a strong pressing force is rotatably disposed at a symmetric position of the backup roller 1 in the diametrical direction with respect to the thermal head 5. 1 and a pressure roller 8, a predetermined paper 9 such as plain paper is inserted, and the backup roller 1 is rotated to drive the paper 9 to the backup 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 4. The ink ribbon 4 used for the recording is formed by, for example, laminating an ink formed by mixing a wax-based component with a colorant on the surface of a base film made of resin.

Next, the operation of this embodiment described above will be described.

First, with the sheet 9 inserted between the backup roller 1 and the pressure roller 8, the pressure roller 8 is pressed against the backup roller 1 with a strong pressing force, and the thermal head 5 is connected to the ink ribbon 4 and the backup roller. Press it to 1. Then, the heater 2 having the backup roller 1 built therein is heated to a temperature T1 at which the ink of the ink ribbon 4 is not melted, and then a plurality of heating elements of the thermal head 5 are selectively heated. In this state, the backup roller 1 is rotated clockwise by a driving device (not shown) to convey the paper 9 in the direction indicated by arrow A in FIG. 1, and the ink ribbon 4 is also moved in the direction indicated by arrow B by the ribbon roll 7. To convey at a predetermined speed. In other words, in this embodiment,
The ink ribbon 4 is conveyed by the frictional force between the intermediate transfer body 3 on the outer periphery of the backup roller 1 and the ink ribbon 4, and is further conveyed downstream from the position where the thermal head 5 is arranged in the conveyance direction of the ink ribbon 4. The ink ribbon 4 is wound by the rotational driving of the bobbin 6a on the winding side (by a driving source (not shown)). At this time, since the winding speed changes depending on the radius of the ink ribbon 4 wound around the winding bobbin 6a, it is necessary to rotate the bobbin 6 slightly faster than the conveying speed of the backup roller 1. However, the difference in rotational speed is absorbed by providing a known slip mechanism in the winding mechanism.

At this time, the ink of the ink ribbon 4 at the portion facing the heat generating element of the thermal head 5 is melted and transferred to the intermediate transfer member 3 covering the surface of the backup roller 1 to form a primary recording image. It is formed.

Then, in a state where the ink transferred to the intermediate transfer member 3 is heated to a constant temperature by the heater 2 of the backup roller 1 to cause the ink to have a certain viscosity, the paper 9 is held by the pressure roller 8. The primary recording image is brought into pressure contact with the backup roller 1, and the paper 9 is conveyed so that the peripheral speed and the relative speed of the intermediate transfer member 3 are not generated, so that the primary recording image is retransferred to the paper 9 and desired recording is performed. Can be done.

As described above, in the thermal transfer printer of this embodiment, since the intermediate transfer body 3 is formed of the material having the adhesiveness, the driving force of the backup roller 1 is applied to the surfaces of the ink ribbon 4 and the backup roller 1. It is possible to convey the ink ribbon 4 by utilizing a large frictional force with the coated intermediate transfer body 3 having adhesiveness,
The conveyance speed of the ink ribbon 4 can be left to the rotation speed of the backup roller 1. That is, the backup roller 1 and the ink ribbon 4 can be conveyed in synchronism with each other, and it is possible to prevent the recording accuracy from being defective due to a slight difference between the rotation speed of the backup roller 1 and the conveyance speed of the ink ribbon 4. it can.

Further, as described above, the intermediate transfer member 3 uses a material having adhesiveness, and even if printing is performed with the pressing force P of the thermal head 5 set to 100 to 300 g / cm ² , the ink ribbon of Slip does not occur, so that the ink thickness becomes stable and becomes uniform, and a clearer recorded image can be obtained.

In this embodiment, even if an attempt is made to measure the friction coefficient of the intermediate transfer member 3, ribbon slip does not occur and the ink ribbon 4 is torn by a tensile force and cannot be accurately measured. However, it is clear that the coefficient of friction is 1.0 or more.

According to the thermal transfer printer of this embodiment, the pinch roller, which controls the feeding speed of the ink ribbon 4 on the winding side of the ink ribbon 4 in the mechanism of the conventional thermal transfer printer, is not required. The feed mechanism is simplified, and the thermal transfer printer can be downsized and the cost can be reduced.

FIG. 2 is a sectional view showing the partial construction of a printer according to the second embodiment of the present invention. The same parts as those in the first embodiment are designated by the same reference numerals and will be described.

Intermediate transfer member 3 in this thermal transfer printer
Is an intermediate transfer belt 10 formed of a sheet-shaped endless belt.
Is formed on the outer surface of the.

The cylindrical platen roller 1 is arranged so as to face the heating element of the thermal head 5 with the ink ribbon 4 interposed therebetween.
1 is arranged in the platen roller 11,
A heater 2 for heating the platen roller 11 is provided. Further, a cylindrical backup roller 12 is arranged so as to face the pressure roller 8 which can move forward and backward in the direction indicated by the arrow C so as to press the intermediate transfer belt 10 and the paper 9 with the paper 9 interposed therebetween. A heater 13 for heating the backup roller 12 is arranged inside the backup roller 12. The intermediate transfer belt 10 is wound around the outer circumferences of the platen roller 11 and the backup roller 13 in a tensioned state. Therefore, the intermediate transfer belt 10 and the sheet 9 are interposed between the pressure roller 8 and the backup roller 12.

The material of the intermediate transfer member 3 coated on the surface of the intermediate transfer belt 10 is that it can temporarily hold the primary recording image formed of an ink layer and has a smooth surface. Sheet, plastic sheet,
It can be configured by a metal sheet or the like, or a combination thereof. For example, an endless polyimide film that covers the surface of the intermediate transfer belt 10 can be used by being coated with silicon rubber having strong adhesion. In this case, the thickness of the polyimide film is 50 μm to 500 μm. The film thickness of 10 μm to 500 μm was optimal. Preferably, the polyimide film had a thickness of 50 μm and the silicon rubber had a film thickness of 50 μm to 200 μm.

The adhesiveness of the silicon rubber as the intermediate transfer member 3 is expressed by its smoothness (surface roughness) and hardness (JIS hardness). The smoothness is 10 μm in Rmax.
From 40 to 40 μm, and the hardness is 10 to 80 degrees, preferably 10 to 40 degrees, the experimental result has been obtained that the adhesiveness to the ink ribbon is good.

The platen roller 11 is connected to a driving means (not shown) and is driven to rotate clockwise. The rotation of the platen roller 11 causes the intermediate transfer belt 10 to be indicated by an arrow D in FIG. And the ink ribbon 4 and the paper 9
Also runs in the directions indicated by arrows E and F, respectively. The ink ribbon 4 having the same structure as that of the first embodiment is used. The platen roller 11 and the backup roller 12 are made of metal,
The heaters 2 and 13 are hollow so that they can be built therein. If necessary, the outer circumferences of the platen roller 11 and the backup roller 12 may be covered with an elastic material such as rubber to form a two-layer structure.

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

First, the thermal head 5 is attached to the ink ribbon 4
Also, the backup roller 12 is pressed against the intermediate transfer belt 10 via the intermediate transfer belt 10. At this time, the platen roller 11 is heated by the built-in heater 2 at a temperature T2 at which the ink of the ink ribbon 4 is not melted, and then a plurality of heating elements of the thermal head 5 are selectively heated. In this state, by rotating the platen roller, the intermediate transfer belt 10 wound in a tension state between the platen roller 11 and the backup roller 12 is made to run, and the backup roller 1 is made to run The ribbon 4 is conveyed at a constant speed. That is, the thermal transfer printer of the present embodiment conveys the ink ribbon 4 by frictional driving between the intermediate transfer body 3 of the intermediate transfer belt 10 and the ink ribbon 4, and the winding process of the conveyed ink ribbon 4 Is performed in the same manner as in the first embodiment, and the description thereof will be omitted.

When the heating elements of the thermal head 4 generate heat and the ink of the ink ribbon 4 is partially melted, the ink is transferred to the intermediate transfer body 3 formed on the surface of the intermediate transfer belt 10 and the intermediate transfer body 3 is transferred. A primary recording image made of ink is formed on the surface of the.

Then, the intermediate transfer belt 10 at the portion where the primary recording image is held faces between the pressure roller 8 and the backup roller 12, and the pressure roller 8
When the paper is brought into pressure contact with the primary recording image on the intermediate transfer body 3, the backup roller 12 on the intermediate transfer body 3 side is heated by the heater 13 to the optimum temperature T3 for retransfer. By running 10 in the arrow direction and paper 9 in the arrow direction,
The primary recording image on the intermediate transfer belt 10 is re-transferred onto the paper 9 to finally perform recording, and thereafter, the pressure roller 8 is released from the pressure contact with the intermediate transfer belt 10.
The above process is repeated to record each image.

In the thermal transfer printer having the intermediate transfer belt 10 of this embodiment, the driving force of the platen roller 14 causes the intermediate transfer belt 10 to travel, and the driving force of the platen roller 14 is applied between the ink ribbon 4 and the intermediate transfer belt 10. The ink ribbon 4 is conveyed by transmitting it to the ink ribbon 4 by utilizing the frictional force between the surface of the intermediate transfer member 3 and the adhesion. That is, the thermal transfer printer of the present embodiment is similar to the first embodiment in that the conveyance of the intermediate transfer body 3 and the ink ribbon 4 is synchronized by using the frictional force, and the same effect can be obtained. Is.

However, in this embodiment, the heater 13 is built in the backup roller 12 disposed on the side for retransferring the primary recording image to the sheet 9, and the heating applied to the platen roller 11 is Separately, since it is possible to control the temperature environment by heating the backup roller 12 to the optimum temperature for retransfer of the primary recording image, it is possible to obtain a better recording result.

The present invention is not limited to the above embodiment, but can be modified as necessary.

[0042]

As described above, since the present invention is constructed and operates, it is possible to carry the ink ribbon by utilizing the driving force of the backup roller as the frictional force between the ink ribbon and the intermediate transfer member. Yes, the ink ribbon transport speed can be entrusted to the rotation of the backup roller, and the backup roller and ink ribbon transport can be synchronized, so there is a subtle difference between the backup roller rotation speed and the ink ribbon transport speed. It is possible to prevent defective recording accuracy due to Moreover, if a material having adhesiveness is used as the intermediate transfer member, ink slip is less likely to occur, so that the ink thickness becomes stable and uniform, and a clearer recorded image can be obtained. Furthermore, since the ribbon feed mechanism can be simplified, the thermal transfer printer can be downsized and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of a partial configuration of a thermal transfer printer according to a first embodiment of the present invention.

FIG. 2 is a partial configuration sectional view of a thermal transfer printer according to a second embodiment of the present invention.

FIG. 3 is a partial configuration sectional view of a conventional thermal transfer printer.

[Explanation of symbols]

 1,12 Backup roller 2,13 Heater 3 Intermediate transfer body 4 Ink ribbon 5 Thermal head 6 Bobbin 7 Ribbon roll 8 Pressure roller 9 Paper 10 Intermediate transfer belt 11 Platen roller

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Isao Owada 1-7 Yukiya Otsuka-cho, Ota-ku, Tokyo Alps Electric Co., Ltd.

Claims (2)

[Claims] 1. A thermal recording head which selectively heats a heating element to partially melt the ink of the ink ribbon, and a primary recording image by transferring the ink of the ink ribbon melted by the heat generation of the thermal head. In the thermal transfer printer having an intermediate transfer member on which the intermediate transfer member is formed and a retransfer means for retransferring the primary recording image transferred on the intermediate transfer member to a sheet to perform desired recording, the intermediate transfer member is provided on the surface thereof. Is formed of a material having a coefficient of friction with the ink ribbon of 1.0 or more. 2. The intermediate transfer member according to claim 1,
A thermal transfer printer whose surface is made of silicone rubber.