JPH04224965A - Thermal transfer printer - Google Patents

Abstract

PURPOSE:To prevent heat seal from occurring to an ink sheet and to make high speed printing executable by providing a means that supplies a mold releasing agent that is in liquid state under normal temperature to the rear surface of the ink sheet that comes in contact with the surface of resistance heating elements in a thermal print head. CONSTITUTION:A liquid mold releasing agent supply device 26 is provided between an ink sheet feed roller 14a and a resistance heating element line 3. A mold releasing agent 27 that is in liquid state under normal temperature is applied to the rear surface, the surface that comes in contact with the resistance heating element line 3 in a thermal print head 1. However, there is no possibility that the mold releasing agent 27 becomes adherent to a thermosensitive ink layer 20 of the ink sheet 12 that is wound in a roll. Thereby transferrability of the ink is ensured.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention involves superimposing an ink sheet having a heat-sensitive ink layer coated on one side of a plastic sheet and a print sheet having an ink-receiving surface, and then inserting a print head from the back side of the ink sheet. The present invention relates to a thermal transfer printer that prints by applying an action.

0002

2. Description of the Related Art A thermal print head having resistive heating elements arranged in rows and segmented for each print pixel is well known and has been widely put into practical use.

In addition to the method of printing using the thermal print head described above, in addition to the method of directly applying the print head to the heat-sensitive recording paper coated with a heat-sensitive coloring agent, there is also a method of printing using a heat-sensitive ink layer on one side of a plastic sheet. There is a method in which a coated ink sheet and a print sheet having an ink-receiving surface are overlapped, and printing is performed by operating a print head from the back side of the ink sheet. A thermal transfer printer using the latter method transfers the colorant on the ink sheet to the ink receiving surface of the print sheet to perform printing by applying a signal voltage according to an image signal to the print head.

FIG. 7 is a diagram showing a conventional thermal transfer printer of this type. In FIG. 7, 1 is a thermal print head, 2 is a ceramic substrate, 3 is a resistance heating element line, and 4 is a thermal print head.
5 is a support plate, 5 is a radiation fin, 6 is a driver circuit, 7 is a protective cover, and 8 is a connector. Further, 11 is a platen roller, 12 is an ink sheet, 13 is a print sheet, 14a is an ink sheet supply roll, and 14b is an ink sheet take-up roll.

FIG. 8 is a schematic enlarged view of the printing operation section of the thermal transfer printer shown in FIG. 7. As shown in FIG. The heat generating section of the thermal print head 1 is configured as follows. As shown in the figure, a glass glaze layer 15 is provided on the ceramic substrate 2 to form a heat insulating and heat generating portion in a protruding manner, and segmented electrodes 16 are provided on the surface of the glass glaze layer 15. The surface of the electrode 16 is coated with a heating resistor 17, and the outermost surface is coated with a wear-resistant layer 18.

The ink sheet 12 is a thin plastic sheet 19 coated with a heat-sensitive ink layer 20 on one side and a slippery layer 21 on the other side. As the ink layer 20, heat-melting ink or sublimation transfer ink containing a dye that moves and diffuses with heat is applied.

The print sheet 13 includes a base paper 22 made of synthetic paper, paper, etc., and an ink-receiving surface processing portion 23 that receives ink and makes it possible to record an image on the surface of the base paper 22. This ink-receiving surface processing section 23 is preferably processed to make the surface smooth for heat-melting ink, and for heat-sublimation transfer ink, it is preferably processed to make the surface smooth. Preferably one coated with a large resin.

The platen roller 11 is constructed by wrapping an elastic member 25 such as high-hardness rubber around the surface of a core metal 24, and is configured to generate a high pressure contact force at the transfer portion.

[0009] When high-speed printing is performed using a thermal transfer printer having such a configuration, the heat generating portion is heated to a high temperature of several hundred degrees within a short time. As the plastic sheet 19 that forms the base of the ink sheet 12, a polyester film of several to tens of microns is normally used, but the plastic sheet 19 will melt at the above-mentioned high temperatures. . Therefore, if the plastic sheet 19 is used with the surface exposed,
There is a problem in that the plastic sheet 19 is fused to the heat generating part of the print head 1.

In order to eliminate this problem, the surface of the plastic sheet 19 is covered with a slippery layer 21. The properties of the slippery layer 21 include that it is a thin film that provides a sufficient slippery effect, that it does not seize on the thermal head 1;
It is required that the ink layer is not adversely affected even if the ink sheet supply roll 14a is handled in a wound state. As a lubricating agent for the lubricating layer 21 that satisfies such constraints, it has been proposed to use a fluororesin or a silicone resin as a main ingredient, with fine particles of silica, talc, etc. added to the resin.

[0011]

[Problem to be Solved by the Invention] However, these lubricants are supplied in a state coated on the back of the ink sheet in advance, and were selected under the constraints of not having a negative effect on the thermal ink. Because of this, it has not been able to fully demonstrate the required functions and effects, which has been a major hindrance to high-speed printing.

Therefore, an object of the present invention is to easily and stably provide sufficiently high lubricity and mold releasability between the print head and the back surface of the ink sheet without adversely affecting the heat-sensitive ink layer of the ink sheet. An object of the present invention is to provide a new thermal transfer printer that can prevent thermal fusion of ink sheets and realize high-speed printing.

[0013]

[Means for Solving the Problems] In order to solve the above problems and achieve the objects, the following measures have been taken in the present invention.

(1) An ink sheet coated with a heat-sensitive ink layer on one side of a plastic sheet and a print sheet having an ink-receiving surface that receives ink and enables image recording are superimposed, and the ink sheet is A thermal print head having resistive heating elements segmented for each pixel and arranged in a row is arranged on the back side, and the resistive heating elements of this thermal print head are brought into pressure contact with the back side of the ink sheet, In a thermal transfer printer configured to apply a print image signal to the thermal print head and transfer heat-sensitive ink material to the ink-receiving surface of the print sheet, ink flows from an ink sheet supply section to a resistance heating element of the thermal print head. The sheet path section is provided with means for supplying a liquid release agent at room temperature to the back surface of the ink sheet that is in contact with the surface of the resistance heating element of the thermal print head.

(2) An application means for applying a liquid release agent to the back surface of the ink sheet is attached to the upstream end of the resistance heating element in the thermal print head.

(3) A means for applying a liquid mold release agent at room temperature is integrally attached to the ink sheet supply side of the cassette in which the ink sheet is wound and stored.

(4) Using an ink sheet formed by coating the back surface of mold release agent microcapsules, which are cassettes containing a liquid mold release agent inside a film (a film that can be destroyed by heat or pressure). A liquid release agent was supplied by destroying the release agent microcapsules of this ink sheet.

[0018]

[Function] As a result of taking the measure (1), it becomes possible to easily supply and use a mold release agent which is liquid at room temperature and has a large effect without adversely affecting the ink layer. In this way, it is possible to appropriately provide the lubricity and mold releasability necessary for high-speed printing.

As a result of taking the measure (2), the mounting mechanism for the liquid release agent application means is simplified. Therefore, it becomes possible to easily apply the liquid release agent, and the printer does not need to be enlarged.

As a result of taking the measure (3), the liquid release agent is automatically replenished when the ink sheet is replaced. Therefore, there is no need to perform a special replenishment operation separately.

As a result of taking the measure (4), high lubricity and mold releasability can be imparted simply by processing the ink sheet alone. As a result, there is no need to add or process special members to the printer body or the ink sheet cassette, and it is possible to avoid the configuration of the printer from becoming complicated and large.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 3 are diagrams showing a first embodiment of the present invention. As shown in FIG. 1, the print head 1 has resistive heating element lines 3 arranged on a ceramic substrate 2 in rows and segmented in the main scanning direction. An aluminum plate 4 and heat radiation fins 5 are attached to the back surface (upper surface in the figure) of the ceramic substrate 2 for supporting the substrate 2 and dissipating heat. Surface of ceramic substrate 2 (lower surface in the figure)
A driver circuit 6 is mounted on the top, and its surface is covered with a protective cover 7. 8 is a connector for connecting to the power supply section.

A platen roller 11 is arranged so as to face the resistance heating element line 3. The ink sheet 12 and print sheet 13 are configured to be printed by passing through the nip portion of the platen roller 11. That is, when a print image signal is sent through the connector 8 while the ink sheet 12 and print sheet 13 are being conveyed in the direction of the arrow as the platen roller 11 rotates, this signal is converted into a thermal head drive signal by the driver circuit 6. , and selectively generate heat from each element of the resistance heating element line 3. In this way, the thermal ink material is transferred to the ink-receiving surface of the print sheet 13, and printing is performed. 14a is an ink sheet supply roll, and 14b is an ink sheet take-up roll.

Reference numeral 26 shown in FIG. 1 indicates a liquid mold release agent supplying device, the structure of which will be explained in detail later. This device 26 connects the ink sheet supply section to the resistive heating element line 3.
The ink sheet 1 is placed in the ink sheet path leading to the ink sheet 1.
A liquid mold release agent is supplied to the back surface of the mold.

FIG. 2 is a schematic enlarged view of the printing operation section of the thermal transfer printer shown in FIG. 1. As shown in FIG. As shown in the figure, a glass glaze layer 15 is provided on the ceramic substrate 2 to make the heat-insulating and heat-generating portions protrude as protrusions along the main scanning direction, and segmented electrodes 16 are provided on the surface of the glass glaze layer 15. be. The surface of the electrode 16 is coated with a heating resistor 17, and the outermost surface is coated with a wear-resistant layer 1.
8 is coated.

The ink sheet 12 is a thin plastic sheet 19 coated with a heat-sensitive ink layer 20 on one side. On the other side of the plastic sheet 19, a liquid mold release agent 27 is supplied and coated from a liquid mold release agent supplying device 26 during the printing process. As the ink layer 20, heat-melting ink or sublimation transfer ink containing a dye that moves and diffuses with heat is applied.

The print sheet 13 has an ink-receiving surface treated portion 23 on the surface of a base paper 22 made of synthetic paper, paper, or the like. That is, when the ink layer 20 is a heat-melting ink, processing is performed to make the surface smoothness of the base paper 22 finer, and when it is a heat-sublimation transfer ink, a process is performed to make the surface smoothness of the base paper 22 finer, and when the ink layer 20 is a heat-melting ink, a dye-compatible ink such as thermoplastic polyester is used. coated with a highly resistant resin.

The platen roller 11 is constructed by wrapping an elastic member 25 such as high-hardness rubber around the surface of a metal core 24, and is configured to generate a high pressure contact force at the transfer portion.

In this embodiment, a liquid release agent supplying device 26 is provided between the ink sheet supply roll 14a and the resistance heating element line 3, and the liquid release agent supply device 26 is provided between the ink sheet supply roll 14a and the resistance heating element line 3 of the thermal print head 1. The printing process is characterized in that a mold release agent 27, which is liquid at room temperature, is supplied and applied onto the surface in contact with the surface.

[0030]Thus, although the mold release agent 27 is liquid at room temperature and has a large effect, the mold release agent 27
There is no fear that the heat-sensitive ink layer 20 of the rolled ink sheet 12 will be adhered to, and there is no fear that the ink transferability will be impaired.

Note that if the application means for applying the liquid release agent to the back surface of the ink sheet 12 is attached to the upstream end of the resistance heating element line 3 in the thermal print head 1, the liquid release agent can be applied. The mechanism for attaching the means is simplified. Therefore, it becomes possible to easily apply the liquid mold release agent 27, and the printer does not need to be enlarged.

There are no particular restrictions on the mold release agent that is liquid at room temperature as long as it does not deteriorate the thermal print head 1 or attack the base material of the ink sheet. Examples of suitable mold release agents include organopolysiloxanes (hereinafter referred to as silicone oils).

Silicone oil has excellent mold release properties and lubricating properties, as well as high insulating properties and inertness, and not only does it not attack the protective coating layer of the thermal print head 1, but also has excellent lubricating properties. It also has the effect of increasing the durability of the protective coating layer. Further, it is possible to select a material having a viscosity compatible with various supply means described later. Note that it is preferable to select and apply a material whose vaporization temperature and dispersion temperature are higher than the heat generation temperature of the thermal print head.

[0034] The necessary film thickness of the mold release agent in the heat generating part is sufficient to be extremely thin, on the order of microns or less. Therefore, the amount of mold release agent supplied may be extremely small, and there is no fear that the supplied mold release agent will scatter and contaminate the surrounding area.

FIGS. 3A and 3B are diagrams showing a specific example of the structure of the liquid mold release agent supply device 26. Figure 3(a)
As shown in FIG. 2, a backup roller 29 and a coating roller 30 are arranged to face each other with the ink sheet 12 in between. The application roller 30 has an open-cell foam 3 around the core metal 31.
2 are fitted together. The foam 32 is impregnated with a liquid release agent such as silicone oil, and acts to apply the silicone oil to the back surface of the ink sheet 12 as the ink sheet 12 moves.

FIG. 3(b) is a diagram showing another example of the mold release agent supply device 26. 40 is a coating roller, 41 is a roller body, and 42 is a coating member made of open-cell foam. The amount of silicone oil supplied as a mold release agent is extremely small and has sufficient effects. For this reason, it is preferable to suppress the amount of application to reduce the amount of wear. To this end, in the configuration shown in FIG. 3(b), grooves are formed along the axial direction in the area of the roller body 41 excluding the bearings at both ends, and absorbent material such as open-cell foam is inserted into the grooves. A coating member 42 impregnated with silicone oil is filled and installed. With this configuration, the proportion of the volume of the foam portion can be increased compared to the surface area of the application member 42, so that the amount of application can be suppressed and the consumption of silicone oil can be controlled to a desired amount. . According to the configuration shown in FIG. 3(b), silicone oil is intermittently applied onto the ink sheet 12. The silicone oil captured in the resistance heating element line 3 is gradually spread over the ink sheet 12 and is consumed. Therefore, even if replenishment is performed intermittently as described above, there is no problem in its operation and effect.

By the way, the mold release agent supply device shown in FIGS. 3(a) and 3(b) has no inconvenience in its operation or effect, but the silicone oil is completely consumed after long-term use. If it is stored, maintenance measures such as replenishing silicone oil or replacing the application roller will be required.

FIG. 4 shows a second embodiment, which does not require such maintenance means. In FIG. 4, 50 is an ink sheet cassette, 51 is an ink sheet supply chamber, 52 is an ink sheet winding chamber, 53 is a bridge, 55 is a pad holder, and 56 is an ink sheet cassette.
indicates a silicone oil pad, and 57 indicates a back plate.

The silicone oil pad 56 is installed so as to be located in the path from when the ink sheet 12 is pulled out from the supply chamber 51 to the resistance heating element line 3 of the thermal print head 1, which is not shown in this figure. It will be done. The silicone oil pad 56 is provided with a length approximately equal to the width of the ink sheet 12 in a direction perpendicular to the moving direction of the ink sheet 12. The pad 56 is integrally attached to the ink sheet cassette 50 by a pad holder 55. Preferably, the back plate 57 is also attached integrally with the ink sheet cassette 50. The silicone oil pad 56 is made by impregnating a porous material such as open cell foam or felt with silicone oil.

With the above configuration, the silicone oil pad 56 is automatically replaced every time the ink sheet cassette 50 is replaced. Therefore, troublesome maintenance management is eliminated.

In each of the embodiments described above, an example was shown in which a means for supplying a liquid mold release agent such as silicone oil was provided separately from the ink sheet 12. However, the means for supplying the mold release agent such as silicone oil may have other configurations.

FIG. 5 is an explanatory diagram of a third embodiment corresponding to claim 4 of the present invention, and is a diagram showing a cross-sectional structure of the ink sheet 12. 60 is an ink sheet, 61 is a plastic base film, 62 is a heat-sensitive ink layer, 63 is a back coat layer, and 64 is a microencapsulated liquid mold release agent. The plastic base film 61 and the heat-sensitive ink layer 62 have well-known structures, so a description thereof will be omitted.

The back coat layer 63 is coated on the back side of the ink sheet 60 and contains release agent microcapsules 64.
This is a coat layer in which the following particles are dispersed in a binder resin.

The mold release agent microcapsules 64 are encapsulated by using a liquid mold release agent such as silicone oil as a core material and encapsulating it with a film that can be destroyed by heat or pressure.

When the ink sheet 60 reaches the resistance heating element line 3 of the thermal print head 1, it is subjected to strong pressure and high heat at that portion. Therefore, the film of the mold release agent microcapsule 64 is torn, and a liquid mold release agent such as silicone oil is released.

According to the above structure, the release agent microcapsules 64 maintain their encapsulated state when the ink sheet 60 is stored. This prevents the liquid release agent from adhering to the heat-sensitive ink layer 62 of the ink sheet 60 and causing adverse effects before its use. There is no need to provide any special member for supplying the mold release agent, and an appropriate amount of mold release agent can be reliably supplied.

In the configuration example shown in FIG. 5, the release agent microcapsules 64 are applied to the entire back surface of the ink sheet, but as described above, the release agent is supplied intermittently. Good too.

FIG. 6 is a diagram showing a fourth embodiment that takes this point into consideration, and is a plan view of an ink sheet in which application areas of release agent microcapsules are provided discretely. 70 is an ink sheet, 71, 72~ are microcapsule application areas, C, M,
Y indicates the area where the thermal ink of each color of cyan, magenta, and yellow is applied. By dispersing and limiting the application area of the release agent microcapsules in this way, there is an advantage that the application areas 71, 72, etc. of the release agent microcapsules can be formed easily and at low cost.

[0049] As described above in each of the embodiments, the means for supplying the room temperature liquid mold release agent, in the present invention, the liquid mold release agent can be applied to the ink sheet without any particular restrictions. can. Therefore, even if the heat generation temperature of the thermal head becomes high, the ink sheet is effectively prevented from being thermally fused to the print head. Recording methods that transfer heat-sensitive ink from an ink sheet onto a print sheet include a method that melts and transfers heat-melting ink, and a thermal sublimation transfer recording method that utilizes the thermal diffusion phenomenon of dyes. In thermal sublimation transfer recording, high temperatures are required to transfer a sufficient amount of dye. Therefore, the effects of implementing the present invention are extremely large. Further, by using a mold release agent that is liquid at room temperature, it is possible to prevent wear of the surface protection layer 18 of the thermal print head 1 and improve head durability.

[0050]

According to the present invention, it is possible to easily and stably provide sufficiently high lubricity and a release agent between the print head and the back surface of the ink sheet without adversely affecting the heat-sensitive ink layer of the ink sheet. It is possible to effectively prevent the ink sheet from being thermally fused to the resistance heating element line of the thermal print head, resulting in the effect of enabling high-speed printing.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a thermal transfer printer according to a first embodiment of the present invention.

FIG. 2 is a schematic enlarged cross-sectional view of a print action section according to the same embodiment.

FIG. 3 is a diagram showing a specific example of a liquid mold release agent supply device according to the same embodiment.

FIG. 4 is a diagram showing the configuration of an ink sheet cassette according to a second embodiment of the present invention.

FIG. 5 is a sectional view showing the structure of an ink sheet according to a third embodiment of the present invention.

FIG. 6 is a plan view showing the structure of an ink sheet according to a fourth embodiment of the present invention.

FIG. 7 is a diagram showing the configuration of a conventional thermal transfer printer.

FIG. 8 is a schematic enlarged cross-sectional view of a print action section according to the conventional example.

[Explanation of symbols]

1...Thermal print head, 2...Ceramics substrate,
3... Resistance heating element line, 4... Aluminum plate, 5... Heat radiation fin, 6... Driver circuit, 7... Protective cover, 8... Connector, 11... Platen roller, 12... Ink sheet,
13...Printed sheet, 14a...Ink sheet supply roll, 14b...Ink sheet take-up roll, 15...Glass glaze layer, 16...Segmented electrode, 17...Heating resistor, 18...Abrasion resistant layer, 19...Plastic sheet , 20... Heat-sensitive ink layer, 22... Base paper, 23... Ink receiving surface processing section, 24, 31... Core bar, 25... Elastic member, 26... Liquid release agent supply device, 27... Release agent, 29 ... Backup roller, 30 and 40 ... Application roller, 32
...open cell foam, 41...roller body, 42...coating member made of open cell foam.

Claims (4)

[Claims] 1. An ink sheet coated with a heat-sensitive ink layer on one side of a plastic sheet and a print sheet having an ink-receiving surface that receives ink and enables image recording are superimposed, and the back side of the ink sheet is coated with a heat-sensitive ink layer. A thermal print head having resistive heating elements segmented for each pixel and arranged in a row is disposed on the side, and the resistive heating elements of this thermal print head are pressed against the back surface of the ink sheet. In a thermal transfer printer configured to apply a print image signal to a thermal print head and transfer heat-sensitive ink material to an ink-receiving surface of the print sheet, an ink sheet extending from an ink sheet supply section to a resistive heating element of the thermal print head. A thermal transfer printer, characterized in that a path section is provided with means for supplying a liquid release agent at room temperature to the back surface of an ink sheet that is in contact with the surface of a resistive heating element of a thermal print head. 2. The method according to claim 1, wherein the application means for applying a liquid release agent to the back surface of the ink sheet is attached to the upstream end of the resistance heating element in the thermal print head. Thermal transfer printer. 3. The thermal transfer according to claim 2, wherein a means for applying a liquid release agent at room temperature is attached integrally with the cassette on the ink sheet supply side of the cassette in which the ink sheet is wound and stored. printer. 4. By using an ink sheet whose back surface is coated with mold release agent microcapsules in which a liquid mold release agent is contained and encapsulated in a film, and by destroying the mold release agent microcapsules of this ink sheet. 2. The thermal transfer printer according to claim 1, wherein a liquid release agent is supplied.