JP6551083B2 - Thermal transfer printing apparatus and thermal transfer printing method - Google Patents

Description

  The present invention relates to a thermal transfer printing apparatus and a thermal transfer printing method in which an image receiving paper is heated in advance to a temperature suitable for printing.

  A thermal transfer printer is known in which an ink ribbon and an image-receiving paper are sandwiched between a thermal head and a platen roll, heat is applied to the ink ribbon from the thermal head, and dye of the ink ribbon is transferred to the image-receiving paper to form an image. ing.

  As the printing speed of the thermal transfer printer has been increased, the energy applied per unit time by the thermal head has been increased, and the amount of heat received by the ink ribbon has been increased accordingly. If the energy applied by the thermal head is too high, the ink ribbon is wrinkled and printing unevenness occurs.

  In order to reduce the energy applied per unit time by the thermal head while increasing the printing speed, it is conceivable to heat the image receiving paper before printing. For example, according to Patent Document 1, auxiliary heating is performed before auxiliary printing by means of auxiliary heating means to heat the receptive layer, and the dye transferability of the receptive layer becomes extremely high, and the dye transferred from the ink ribbon is receptive layer A thermal transfer method for reliably holding the heat transfer is disclosed. Further, in Patent Document 2, energy is applied and heated by irradiating the receiving layer of the image receiving paper with a microwave before the dye is transferred from the ink ribbon, thereby promoting the chelate reaction of the dye contained in the receiving layer. A thermal transfer printer is disclosed.

  However, depending on the heating amount of the receptive layer by the auxiliary heating means etc. before printing, the transfer amount (transfer amount) of the dye from the ink ribbon becomes excessive, and the printing density of the highlight portion (low density portion of gradation) of the image And the image quality of the image formed on the image receiving paper is degraded.

Japanese Patent Application Publication No. 2007-90680 JP 2008-80569

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional situation, and an object of the present invention is to provide a thermal transfer printing apparatus and a thermal transfer printing method capable of printing high quality images on image receiving paper while increasing printing speed.

  In the thermal transfer printing apparatus according to the present invention, an image receiving sheet supply roll having a base sheet and a receiving layer wound thereon to supply the image receiving sheet, and an ink ribbon having a dye layer, a dye on the image receiving sheet A thermal transfer printing apparatus comprising a thermal head for thermal transfer, comprising: a preheating unit for heating the image receiving sheet before the dye is thermally transferred from the ink ribbon; and a space between the preheating unit and the thermal head. A temperature sensor that measures the temperature of the image receiving sheet, and a control unit that controls the preheating unit based on a measurement result of the temperature sensor.

  In the thermal transfer printing apparatus according to an aspect of the present invention, the pre-heating unit heats the image receiving sheet located on the outermost periphery of the image receiving sheet supply roll.

  In the thermal transfer printing apparatus according to an aspect of the present invention, the pre-heating unit is a thermal head, a heating roller, a hot air heater, or a halogen heater.

  In the thermal transfer printing apparatus according to one aspect of the present invention, when the preheating unit is a warm air heater, a peripheral wall portion surrounding the warm air heater is provided.

  In the thermal transfer printing apparatus according to an aspect of the present invention, the pre-heating unit heats the entire inside of the housing of the thermal transfer printing apparatus.

  The thermal transfer printing apparatus according to an aspect of the present invention further includes a storage unit that stores characteristic information of the image receiving sheet, and the control unit supplies the thermal head to the thermal head based on the characteristic information and the measurement result of the temperature sensor. The preheating unit is controlled so that the temperature of the receptive layer of the image receiving sheet to be reached becomes a predetermined temperature.

  In the thermal transfer printing apparatus according to one aspect of the present invention, the porosity of all the layers including the receiving layer laminated on one surface of the base sheet is 0.9 or more.

  In the thermal transfer printing apparatus according to one aspect of the present invention, when the porosity of at least one layer is less than 0.9 among all the layers including the receiving layer laminated on one side of the base sheet, The preheating unit heats the image receiving sheet from the receiving layer side.

  The thermal transfer printing method of the present invention is a thermal transfer printing method in which a thermal head heats an ink ribbon having a dye layer to thermally transfer the dye to an image receiving sheet having a substrate sheet and a receiving layer, and the preheating unit is Heating the image-receiving sheet before the dye is thermally transferred from the ink ribbon, measuring the temperature of the image-receiving sheet between the preheating unit and the thermal head, and controlling the control unit And a step of controlling the preheating unit so that the receiving layer of the image receiving sheet has a predetermined temperature based on the measurement result of the temperature sensor.

  In the thermal transfer printing method according to one aspect of the present invention, the porosity of all the layers including the receptor layer laminated on one surface of the substrate sheet is 0.9 or more.

  According to the present invention, the temperature of the image receiving sheet (image receiving sheet) is monitored by a temperature sensor, and the preheating unit is controlled so that the image receiving sheet reaches a predetermined temperature. You can print high quality images.

It is a schematic block diagram of the thermal transfer printing apparatus which concerns on this embodiment. It is a schematic sectional drawing of an image receiving sheet. It is a functional block diagram of a control part. It is a schematic block diagram of the thermal transfer printing apparatus by a modification. It is a schematic block diagram of the thermal transfer printing apparatus by a modification. It is a schematic block diagram of the thermal transfer printing apparatus by a modification. It is a schematic block diagram of the thermal transfer printing apparatus by a modification. It is a schematic block diagram of the thermal transfer printing apparatus by a modification. (A) and (b) are schematic block diagrams of the thermal transfer printing apparatus by a modification. It is a schematic block diagram of the thermal transfer printing apparatus by a modification.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing the configuration of the main part of the thermal transfer printing apparatus according to the present embodiment.

  As shown in FIG. 1, the thermal transfer printing apparatus includes a thermal head 5 having a plurality of heating elements, and a platen roll 6 provided facing the thermal head 5, and the image receiving sheet 1 and the ink ribbon 4 are thermal It passes between the head 5 and the platen roll 6 in a pressure contact state. The ink ribbon 4 is disposed on the thermal head 5 side, and the image receiving sheet 1 is disposed on the platen roll 6 side.

  The ink ribbon 2 has a dye layer on one side of the substrate, and further has a back layer on the other side. The heating element of the thermal head 5 generates heat, and the ink ribbon 4 is heated from the back layer side, whereby the dye is transferred to the image receiving sheet 1 and an image is formed.

  An image receiving sheet (image receiving paper) 1 is wound around an image receiving sheet supply roll 7, and is fed out and supplied from the image receiving sheet supply roll 7. FIG. 2 is a schematic sectional view of the image receiving sheet 1. The image receiving sheet 1 includes a base sheet 2 and a receiving layer 3 laminated on one side of the base sheet 2. The receiving layer 3 is directly laminated on the base sheet 2.

  As the base sheet 2, the base sheet used for the conventional image receiving sheet can be used. Specific examples of the substrate sheet include high-grade paper, art paper, coated paper, cast-coated paper, glassine paper, condenser paper, paper substrate such as paraffin paper, synthetic paper such as polyolefin and polystyrene, polyethylene terephthalate, polyethylene Heat-resistant polyesters such as naphthalate, polybutylene terephthalate, polyphenylene sulfide, polyether ketone, polyether sulfone, polypropylene, polycarbonate, cellulose acetate, derivatives of polyethylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, polyimide Stretched or unstretched films of resins such as polymethylpentene and ionomer, and laminates of these materials, for example, laminates in which polyethylene layers are formed on both sides of a paper substrate, and the like can be mentioned.

  The receiving layer 3 is for receiving the dye transferred from the dye layer of the ink ribbon 4 in image formation and maintaining the formed image. Examples of the resin for forming the receptor layer 3 include polyolefin resins such as polypropylene, halogenated polymers such as polyvinyl chloride and polyvinylidene chloride, polyvinyl acetate, ethylene vinyl acetate copolymer, vinyl chloride / vinyl acetate Copolymers, vinyl resins such as polyacrylic esters, acetal resins such as polyvinyl formal, polyvinyl butyral and polyvinyl acetal, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polystyrene, acrylic / styrene copolymers, acrylonitrile / styrene Styrene resins such as copolymers, polyamide resins, copolymer resins of olefins such as ethylene and propylene and other vinyl monomers, ionomer resins, cellulose resins such as cellulose diacetate, Li carbonate and the like. These resins can be used alone or as a mixture of two or more in any combination.

  As shown in FIG. 1, the thermal transfer printing apparatus measures the temperature of the preheating unit 22 which heats the image receiving sheet 1 before the dye is transferred from the ink ribbon 4 and the temperature of the image receiving sheet 1 heated by the preheating unit 22. And a control unit 10 for controlling the preheating unit 22.

  The pre-heating unit 22 is disposed between the thermal head 5 and the image receiving sheet supply roll 7 and heats the receiving layer 3 side of the image receiving sheet 1. The temperature sensor 20 can be disposed at any position between the thermal head 5 and the preheating unit 22, but is preferably disposed at a position near the thermal head 5 to measure the temperature immediately before printing. In the thermal transfer printing apparatus, a sensor (not shown) for detecting the presence or absence of the image receiving sheet 1 is provided on the upstream side of the thermal head 5, and the temperature sensor 20 may be disposed in the vicinity of the sensor.

  The temperature sensor 20 is, for example, a non-contact thermometer using an infrared sensor, and measures the surface temperature of the receiving layer 3 of the image receiving sheet 1.

  For the preheating unit 22, a thermal head, a heating roller, a hot air heater, a halogen heater, or the like can be used. When a thermal head or a heating roller is used for the preheating unit 22, a roller 24 may be disposed so that the image receiving sheet 1 is sandwiched between the preheating unit 22 and the roller 24.

  FIG. 3 is a functional block diagram of the control unit 10. The control unit 10 includes a temperature acquisition unit 12, a heating control unit 14, and an image receiving sheet information storage unit 16, and includes a CPU, a memory, and the like. The image receiving sheet information storage unit 16 stores characteristic information of the image receiving sheet 1 such as how many times the image receiving sheet 1 should be heated before printing. The characteristic information is written to the memory by an attendant or the like when the image receiving sheet supply roll 7 is set. Thereby, according to the kind of image receiving sheet 1, the suitable temperature rising temperature by preheating can be set.

  A tag storing characteristic information is attached to the image receiving sheet supply roll 7, and a reader (not shown) is provided in the thermal transfer printing apparatus, and the reading apparatus reads the characteristic information from the tag of the image receiving sheet supply roll 7 set. The image receiving sheet information storage unit 16 may store the image receiving sheet information.

  The temperature acquisition unit 12 acquires a measurement result from the temperature sensor 20. The heating control unit 14 controls the preheating unit so that the image receiving sheet 1 has a predetermined temperature based on the temperature of the image receiving sheet 1 acquired by the temperature acquiring unit 12 and the characteristic information stored in the image receiving sheet information storage unit 16. Control 22 The receptive layer 3 of the image receiving sheet 1 is heated to, for example, about 30 ° C. to 40 ° C. by the preheating unit 22.

  As described above, by heating the image receiving sheet 1 by the preheating unit 22, the energy applied per unit time by the thermal head 5 is suppressed even in a state where the printing speed is increased, and the ink ribbon 4 is damaged. Can prevent the formation of wrinkles. In addition, since the temperature of the image receiving sheet 1 is monitored by the temperature sensor 20 and the preheating unit 22 is controlled to achieve a desired temperature based on the characteristic information, the transfer amount of the dye from the ink ribbon 4 becomes excessive. This can be prevented and a high-quality image can be formed.

  When the image receiving sheet 1 does not have a heat insulating layer between the base sheet 2 and the receiving layer 3, the heat applied from the thermal head 5 to the receiving layer 3 is lost due to the heat transfer to the base sheet 2. In the present embodiment, the image receiving sheet 1 is heated by the preheating unit 22 before printing, and the temperature of the receiving layer 3 is raised to a desired temperature, so that the dye dyeing property of the receiving layer 3 becomes high. The dye transferred from the ink ribbon 4 can be reliably held in the receiving layer 3.

  In the above embodiment, the pre-heating unit 22 heats the receiving layer 3 side of the image receiving sheet 1, but as shown in FIG. 4, the base sheet 2 side may be heated. Heating on the side of the base sheet 2 lowers the heat transfer efficiency to the receiving layer 3 as compared with heating on the receiving layer 3 side, while the receiving layer 3 is gently heated to damage the receiving layer 3 by heat. Can be prevented more effectively.

  As shown in FIG. 5, when the warm air heater 22 </ b> A is used as the preheating unit 22, it is preferable to surround the warm air heater 22 </ b> A with a peripheral wall portion 26 (case). As a result, it is possible to prevent dust and the like from being heated by hot air in the apparatus of the thermal transfer printing apparatus and adhering to the image receiving sheet 1 or the ink ribbon 4.

  As shown in FIG. 6, the pre-heating unit 22 may heat the image receiving sheet 1 wound around the image receiving sheet supply roll 7. The pre-heating unit 22 is disposed in contact with or close to the outermost image receiving sheet 1 among the image receiving sheets 1 wound around the image receiving sheet supply roll 7 and performs heating. The image receiving sheet 1 is wound around the image receiving sheet supply roll 7 with the receiving layer 3 facing outside, for example, and the preheating unit 22 heats the receiving layer 3 side.

  As shown in FIG. 7, a preheating unit 22B may be provided on the rotation shaft portion of the image receiving sheet supply roll 7, and the image receiving sheet 1 wound around the image receiving sheet supply roll 7 may be heated from the inner peripheral side.

  As shown in FIG. 8, the preheating unit 22C may heat the entire inside of the housing of the thermal transfer printing apparatus. For example, the preheating unit 22C supplies warm air into the housing. Hot air exhausted from another mechanism of the thermal transfer printing apparatus may be returned to the housing.

  As shown in FIG. 9A, a heating roller 40 may be disposed instead of the platen roll 6, and the image receiving sheet 1 may be heated from the base sheet 2 side at the time of dye transfer from the ink ribbon 4. The temperature sensor 20 measures the temperature of the image receiving sheet 1 immediately before being fed between the thermal head 5 and the heating roller 40, and the control unit 10 controls the heating roller 40 based on the measurement result. As shown in FIG. 9 (b), the heating roller 40 may be a thermal head 42.

  In the configuration shown in FIGS. 1, 4, and 6, when a thermal head is used for the preheating unit 22, the image receiving sheet 1 may be selectively heated based on image information of an image to be formed. For example, the control unit 10 refers to the image information and compares the area where a large amount of dye is transferred to form a dark image with the area where a small amount of dye is transferred and a light image is formed. The preheating unit 22 is controlled to increase the heating amount, and the heating elements of the thermal head are energized. As described above, by performing preheating in accordance with the transfer amount of the dye, it is possible to form a higher quality image.

  In the above embodiment, an example is described in which the preheating unit 22 is provided on the upstream side of the thermal head 5, that is, on the image receiving sheet supply roll 7 side. However, the thermal transfer printing apparatus transports the image receiving sheet 1 upstream When a printing process is performed to thermally transfer the dye from the ribbon 4 to form an image, as shown in FIG. 10, the preheating unit 22 is located downstream of the thermal head 5 (opposite to the image receiving sheet supply roll 7). ) May be provided.

  In this case, the image forming area of the image receiving sheet 1 fed out from the image receiving sheet supply roll 7 is conveyed to the downstream side, passes through the thermal head 5 once and is heated by the preheating unit 22 and then rewound to the upstream side. While being heated, the dye is transferred from the ink ribbon 4 by the thermal head 5. The temperature sensor 20 is disposed between the thermal head 5 and the preheating unit 22.

  Although the said embodiment demonstrated the structure by which the receiving layer 3 was directly laminated | stacked on the base material sheet 2, another layer may be provided between the base material sheet 2 and the receiving layer 3. FIG. For example, a metal deposition layer may be provided between the base sheet 2 and the receiving layer 3. The metal deposition layer can block the transfer of the dye dyed to the receiving layer 3 to the substrate sheet 2 side.

  A heat insulating layer may be provided between the base sheet 2 and the receiving layer 3. The heat insulating layer has a thermal conductivity lower than that of the base sheet 2 and the receiving layer 3. When the heat receiving layer is provided in the image receiving sheet 1, it is preferable that the preheating part 22 heats from the receiving layer 3 side.

  The heat insulating layer contains hollow particles. The hollow particles are composed of a shell formed of a polymer material and one or more hollow (pore) portions surrounded by the shell. For example, as hollow particles, expandable hollow particles or microcapsule-like hollow particles can be used.

  The average particle size of the hollow particles is 0.4 to 20 μm, preferably 2 to 15 μm. When the average particle diameter of the hollow particles is less than 0.4 μm, the volumetric hollow ratio of the hollow particles is low, and the cushioning property of the image receiving sheet 1 may not be sufficiently exhibited. When the average particle diameter exceeds 20 μm, the smoothness of the heat insulating layer surface is lowered, and the uniformity of the thermal transfer image may be deteriorated. The average particle size of the hollow particles can be measured using a general particle size measuring device.

  The volumetric hollow ratio of the hollow particles (the ratio of the volume of the hollow portion to the volume of the particles) is 50 to 97%, preferably 55 to 95%. When the volumetric hollow ratio of the hollow particles is less than 50%, the cushioning property of the image receiving sheet 1 may not be sufficiently exhibited. Moreover, when the volumetric hollow ratio exceeds 97%, the coating film strength of the heat insulating layer is lowered, and the heat insulating layer may be easily damaged.

  The mass ratio of the hollow particles with respect to the total solid content of the heat insulating layer is 10 to 80 mass%, preferably 15 to 70 mass%. When there is no layer in which the mass ratio of hollow particles is 10% by mass or more between the base sheet 2 and the receiving layer 3 (the mass ratio of hollow particles in the layer between the base sheet 2 and the receiving layer 3 is 10 mass) %), The heat insulating layer is not provided between the base material sheet 2 and the receiving layer 3.

  The heat insulating layer contains hollow particles and a binder resin as main components. The binder resin to be used includes, for example, polyvinyl alcohol resins, cellulose resins and derivatives thereof, water-soluble resins such as casein and starch derivatives, (meth) acrylate resins, styrene-butadiene copolymer resins, urethane resins Water-dispersible resins of various resins such as polyester resin, ethylene-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate copolymer resin, and the like are used.

  The base sheet 2 having a heat insulating layer may be a sheet having a porous foam structure obtained by dissolving and diffusing a gas in a supercritical state in a thermoplastic resin. When the porosity of the foam structure is less than 0.9, it functions as a heat insulating layer.

  The porosity (V) is a numerical value obtained by dividing the density (ρ) of the target substrate by the density (ρ0) of the resin constituting the substrate, and is calculated by V = ρ / ρ0. The density (ρ) of the base material is a density of the base material having a foam structure, and is a numerical value in a configuration including voids. On the other hand, the density (ρ0) of the resin that constitutes the base material is the density of the resin alone without including any voids. In addition, the density of a base material cut out the sample of 10 cm x 10 cm size from a base material, measured the thickness of the cut-out sample, calculated the volume, measured the weight of the sample, and calculated the measured weight It can be obtained by dividing by.

  When a layer having a porosity of less than 0.9 is laminated on the surface of the base sheet 2 on which the receptive layer 3 is formed, the base sheet 2 is provided with a heat insulating layer. On the other hand, when the porosity of all the layers laminated | stacked on the surface in which the receiving layer 3 of the base material sheet 2 is formed is 0.9 or more, a heat insulation layer will not be provided.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, components in different embodiments may be combined as appropriate.

Reference Signs List 1 image receiving sheet 2 base sheet 3 receiving layer 4 ink ribbon 5 thermal head 6 platen roll 7 image receiving sheet supply roll 10 control unit 20 temperature sensor 22 pre-heating unit

Claims (6)

An image receiving sheet having a base sheet and a receiving layer is wound, and an image receiving sheet supply roll for supplying the image receiving sheet;
A thermal head that thermally transfers a dye from the ink ribbon having the dye layer onto the image receiving sheet;
A thermal transfer printing apparatus comprising
A pre-heating unit for heating the image-receiving sheet before the dye is thermally transferred from the ink ribbon;
A temperature sensor for measuring the temperature of the image receiving sheet between the pre-heating unit and the thermal head;
A control unit for controlling the preheating unit based on the measurement result of the temperature sensor;
Bei to give a,
The thermal transfer printing apparatus , wherein the pre-heating unit is a thermal head, a heating roller, or a halogen heater, and heats the image receiving sheet located on the outermost periphery of the image receiving sheet supply roll . A storage unit for storing characteristic information of the image receiving sheet;
The control unit controls the preheating unit based on the characteristic information and a measurement result of the temperature sensor so that a receiving layer of an image receiving sheet supplied to the thermal head has a predetermined temperature. A thermal transfer printing apparatus according to claim 1 . The thermal transfer printing apparatus according to claim 1 or 2 , wherein the porosity of all layers including the receiving layer laminated on one surface of the base sheet is 0.9 or more. When the porosity of at least one layer is less than 0.9 among all the layers including the receiving layer laminated on one surface of the base sheet, the pre-heating unit may thermal transfer printing apparatus according to claim 1 or 2, characterized in that heating from the receiving layer side. A thermal transfer printing method, wherein a thermal head heats an ink ribbon having a dye layer, and thermally transfers the dye to an image receiving sheet having a substrate sheet and a receiving layer,
A step of preheating the image receiving sheet before the dye is thermally transferred from the ink ribbon;
A step of measuring a temperature of the image receiving sheet between the pre-heating unit and the thermal head;
Controlling the preheating unit such that the receiving layer of the image receiving sheet has a predetermined temperature based on the measurement result of the temperature sensor;
Equipped with a,
The image receiving sheet is supplied from an image receiving sheet supply roll,
The thermal transfer printing method , wherein the pre-heating unit is a thermal head, a heating roller, or a halogen heater, and heats the image receiving sheet located on the outermost periphery of the image receiving sheet supply roll . 6. The thermal transfer printing method according to claim 5 , wherein the porosity of all the layers including the receiving layer laminated on one surface of the base sheet is 0.9 or more.

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