JP2008195051A - On-demand foil printing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus which performs printing on-demand (carrying out direct foil printing from data from a PC or the like at a high speed, without forming a stamp and without any problem in the print quality of an image receiving body on which printing has been able to be carried out by conventional hot stamping). <P>SOLUTION: A thermal printer uses the print instructing data from the PC or the like, controls application of a thermal head in accordance with the data, and carries out predetermined printing. Two or more thermal head blocks are provided. A pattern desired to be transferred is printed by a first head, and the same pattern is further printed by second and following heads. Alternatively, the entire printing area is printed by the second head. A transfer ribbon used in the first head has a material which facilitates printing of a foil onto the surface of the image receiving body, and the transfer ribbon used in the second head is a foil ribbon. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a thermal transfer printer, and more particularly to a thermal transfer printer for printing a hot plate foil.

Conventionally, a method for printing a foil has been performed by a hot plate. Fig. 1) shows the shape of the hot plate printing machine.
FIG. 2) shows the hot plate system, and FIG. 3) shows the structure of the hot plate foil.
The biggest problem with the hot plate method is to create a mold for printing. When printing the same contents in large quantities, there are few problems, but there are many problems such as the cost of mold production and the period for printing a small number of lots and various types of foils as a recent request. As a solution to this, a thermal printer for direct foil printing using a thermal printer is already on the market. Fig. 4) shows the appearance of a commercially available direct foil printer.
However, with that printing method,
Although printing is possible on the surface of the receiver such as a clear file having smoothness, the printing process speed is very slow (printing speed is 15 mm / Sec), which is severe for business use. or,
・ For materials that are difficult to transfer (metal, non-woven cloth, Japanese paper, glass, polyolefin, polypropylene, etc.) or receivers with a rough surface, there are defects that cannot be clearly printed, and they are used only in limited areas. The current situation is not.
This is because the hot plate method can transfer heat by pressing a foil against the image receiving body for several hundred milliseconds, while the thermal printer method can only apply heat for several milliseconds. . Printing on the same place for a long time with a thermal head means that the printing speed is slow, and at present, there is no way to limit the printing speed and the image receptor that can be printed. New technology is needed.

Problems to be solved by the invention / consideration

The present invention is based on the current state of foil printing as described above. On-demand (without creating a mold, direct foil printing from data from a PC or the like, to a receiver that can be printed at high speed with a conventional hot stamp, It is an object of the present invention to provide an apparatus for performing printing (no problem in print quality). ,

Means for solving the problem

The current situation is that foil cannot be printed at high speed using a thermal transfer printer.
The reason is,
・ There is a difference from hot stamp printing. In the case of hot stamping, the high temperature (180 ° C. or higher) time required for the foil to be printed is long, such as several hundred milliseconds. Further, the pressing force applied to the image receiving member is transferred by being pressed with a pressing force several tens of times the pressing pressure of the thermal printer. In the thermal printer, the time taken for the foil is at most several milliseconds, and the pressing pressure is also 1/10 or less of the hot stamp. It is very difficult to print (transfer) a hot stamping foil ribbon originally designed and manufactured for hot stamping with a thermal printer.
This proposal solves this problem from a completely new perspective.
In other words, a material on which the hot stamping foil is easy to transfer (easily glue or stick) is placed on the surface of the image receptor in advance (printed; hereinafter referred to as preprinting), and the hot stamping foil is printed (transferred) thereon. To do.
The difficult part of this solution is that the image receptor is made of a wide variety of materials, and most of them are materials that are not easily transferred with thermal printers. And most of the surface is rough.
Printing on non-smoothness is a difficult problem for thermal printers.
However, this proposal solved these two problems and made hot stamp foil printing possible. In addition, an apparatus embodying this method has been invented.

Effect of invention and consideration

By realizing an apparatus capable of printing hot plate foil on demand, it is possible to cope with a receiver that is currently printed with a hot plate.

Example 1

Next, a thermal printer according to an embodiment of the present invention will be described based on FIG. 5) a foil printer structure and FIG. 6) a printing method. FIG. 5) is a schematic diagram of the structure of an on-demand foil printer.
[1] Thermal head block for pre-printing The thermal head uses an edge type thermal head in terms of print quality and head pressure. The thermal head block allows the head to be lifted except during printing, preventing wasteful use of the ribbon and ensuring ease of ribbon replacement.
The thermal head has the same functions as an ordinary thermal printer, and has a temperature sensor and thermal history control for temperature control to ensure print quality.
[2] Thermal head block for hot stamp foil printing The structure and function are the same as the head block of [1].
[3] Ribbon winding mechanism for preprint This is a ribbon winding mechanism for a standard thermal transfer printer.
[4] Ribbon feeding mechanism for preprint This is a standard ribbon feeding mechanism for a thermal transfer printer.
[5] and [6] have the same mechanism as [3] and [4]. Note that a rotational angular velocity sensor is attached to the mechanisms [3] to [6] so that tension torque can be applied according to the winding state of the ribbon. In this case, in particular, the foil ribbon is likely to stick (thermally stick) to the thermal head, and this sensor is indispensable from the prevention and detection. The reason why the hot stamp foil ribbon is sticking is that the back coating material, which is common in the thermal transfer ribbon, is not used for the hot stamp foil on the back surface of the ribbon. For thermal transfer printers, it is used to prevent sticking.
[5] Hot stamp foil ribbon winding mechanism [6] Hot stamp ribbon feeding mechanism [7] Image receiver (notebook, clear file, book, etc)
Image receivers range from a thickness of about 0.3 mm like a clear file to a cover of about 5 cm on a book cover. This is a major problem because there are many distances between the thermal head and the image receiving surface.
[8] Image receptor transport mechanism The thickness of the image receptor is from 0.3 mm to several centimeters. In order to cope with them, the present conveying apparatus is configured such that the printing surface of the image receiving body can be set at a fixed position relatively perpendicular to the thermal head.
In this implementation plan, the device can be moved up and down manually, but an automatic adjustment device is possible. A device for relative home position will now be described.
This is the content described in <Head up / down explanatory diagram> in FIG.
The vertical distance between the head and the receiver is within a certain range.
This means that in the standby state, the vertical distance between the image receiving surface and the thermal head is kept within a certain range.
In the method, the thickness of the “conveying device” is adjusted so that the vertical position of the upper surface of the image receiver placed on the upper surface of the “conveying device” and the head is within a certain range (in this case, 10 mm +/− 2 mm). In this case, it is possible to adjust by making a plurality of thin layers, or a device that moves up and down manually may be used.
・ The head block is normally in a head-up state.
The vertical distance between the image receiving surface and the thermal head in the above is stopped at a position of 10 mm +/− 2 mm.
・ At the start of printing, move the head downward with the "head position adjustment device" and stop at the optimum position for printing, and start printing.
This device can adjust the head block vertically by using a motor.
・ Optimum position detection is detected by a “pressure sensor”.
・ The thermal head block hits the receiver and is subjected to weighting, and the value reaches a certain value.
According to this mechanism, it is possible to apply a uniform head pressing pressure even to a rough surface, an elastic surface, etc., and to ensure print quality.
The transport device places an image receptor and feeds forward during printing, and back feeds when printing is finished, and stops at a predetermined position.
Further, the image receiving member is adhesive and covers the surface so that there is no excessive movement or displacement. Alternatively, a device for fixing the image receiver can be provided. Since plastic materials such as polyolefin materials and polyester materials expand and contract, it is possible to provide a device for pulling both ends (up and down or left and right directions of printing).
In a thin image receptor such as a clear file, it is effective to use a material that does not slip the surface material of the transport mechanism.
The control device for controlling the printer is almost the same as that of the thermal transfer printer and can be used. Also, it is assumed that drawing on the PC side can be handled by a conventional printer application, and the user can use this printer under the same conditions as when using a one-head thermal transfer printer. In other words, the drawing only draws what is desired to be printed, and the pre-printing and the foil printing are not conscious of the customer.
In this embodiment, the printing unit of the thermal block unit is fixed and the image receiver is moved by the transport device. Conversely, a mechanism in which the image receiving unit is fixed and the printing unit moves may be used.
[9] A fixing roller for chanting the fixing of the transferred foil.
In this case, first, an intermediate layer (a layer for facilitating transfer of the foil is transferred onto the surface of the image receiving member, and the foil is transferred thereon, so that the scratch resistance and scratch resistance tend to be deteriorated. This device is for countermeasures, and is to fix the transferred foil to the chitin, using a metal roller or high hardness rubber roller.
In addition, heating can also increase the effect.
FIG. 6 shows a two-head printing method.
The first preprint print transfers the desired print content.
Printing on the second foil printing head block varies depending on the image receiver.
・ For materials that can hardly or not be printed by direct thermal transfer (PET material, clear file material, etc.)
Print a square or rectangle that includes the area you want to print.
As a result, the foil is neatly printed only at the place printed by the first head.
(Printed). Originally, the second thermal head prints in the same way as the first head, but printing with two thermal heads may cause a color shift or the like. I take this method to get rid of it.
In the case of an image receptor that prints foil directly by thermal transfer and faintly prints (notebook, book cover, etc), the second head block prints exactly the same print as the first head. The optimum quality is ensured by printing.
However, since the two heads cannot be printed at exactly the same position due to mechanical accuracy, there is a possibility that the printing will be slightly blurred at the edge portion.
-Although it is a problem, it is a pre-print ink material, it needs to be changed according to the material of the image receiver. As a way of thinking of measures,
(1) Consider the adhesiveness with the image receiving material. For example, using the same material for the adhesive layer of the preprint ribbon.
(2) To increase the thickness of the transferred layer of the preprint ribbon as much as possible.
This is to thicken the adhesive layer of the preprint ribbon shown in FIG.
This is because, in order to interpolate the roughness of the surface of the image receptor, it is necessary to adhere to the valley with a thick adhesive layer.
Further, as the printing method, two methods as shown in FIG. 7) Preprint method can be considered.
{Circle around (1)} In the bridging method, when the surface of the image receiving body is rough, preprint printing is performed so that a bridge is built at the bottom, and a foil is printed thereon. This is possible with a hot peel type ribbon. 1 is a form of a thermal transfer ribbon.
(2) The other soaking method is possible with a wax-based material that is easily melted by heat.
In this case, considering the scratch resistance and scratch resistance of the foil printed thereon, the bridge method (1) is optimal.
The structure of the preprint ribbon in FIG. 8) will be described.
The preprint ribbon has a three-layer structure in which a release layer, an intermediate layer, and an adhesive layer are laminated in this order from the substrate side. As the base material, various base materials conventionally used as a base material for thermal transfer ribbons can be used, but they must be examined from the viewpoint of durability, heat transfer properties, and cost. In this case, for all three layers, it is necessary to consider the optimum material and thickness in consideration of the surface material and roughness of the image receptor, and the scratch resistance of the foil to be transferred and printed. Provide a preprinted ribbon.
A conventional structure is described below for reference. As a basic one, a polyethylene terephthalate film having a thickness of 2 to 6 μm is often used. A stick prevention layer is applied to the back surface of the substrate.
-A mold release layer is a layer which consists of a heat-meltable material which has a wax as a main component, and mix | blends a heat-meltable resin as needed. The coating thickness of the release layer is 0.25 μm or less.
As materials having a melt viscosity of 10 ⁶ cps / 160 ° C. or higher used as a main component in the intermediate layer, for example, polymers or copolymers of methacrylic esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, methyl acrylate, ethyl Examples thereof include polymers or copolymers of acrylates such as acrylates.
Since a high melt viscosity material is used for the intermediate layer, even in the case of foil ink overlap transfer, the bridge effect on the transfer target having poor surface smoothness does not occur, and high quality foil overlap transfer becomes possible. .
In general, the total amount of materials having a melt viscosity of 10 ⁶ cps / 160 ° C. or higher as the main component is 50% by weight or more of the intermediate layer.
The coating thickness of the intermediate layer must be determined from the viewpoint of achieving the intended purpose well and not impairing the thermal transfer sensitivity. Generally, it is the range of 0.1-1.0 micrometer.
When the thickness of the intermediate layer is reduced, the bridge effect is hardly exhibited, and when it is thick, the transferability tends to be deteriorated.
-Materials whose melt viscosity used as the main component in the adhesive layer is lower than that of the intermediate layer include, for example, ethylene-vinyl acetate copolymers, olefin copolymers such as ethylene-acrylic ester copolymers, polyamide resins, etc. It is done.
-When the melt viscosity of the main component is low, the adhesive strength to the transferred material is insufficient. On the other hand, when the melt viscosity is high, the unevenness of the transferred material is not followed and the sealing is not sufficient.
-The coating thickness of the adhesive layer is sufficiently thicker than that of a normal thermal transfer printer. If it is thin, the sealing effect on the unevenness of the transfer object is reduced. If it is too thick, problems may occur due to adhesion and scratch resistance.
In this case, the (material + melt viscosity + thickness) of the intermediate layer and adhesive layer must be determined optimally from the material, roughness, and scratch resistance of each image receptor. That is, the optimum value for each receiver may be different.
It is essential to improve the scratch resistance and scratch resistance of the printed foil. For that purpose, it is necessary to increase the nip pressure at the time of printing with the thermal head, but there is a limit naturally. As a complement, after printing with 2 heads, a strong nip pressure (pressing pressure) is applied to the printing surface with a roller (also possible with a heat roller) to give the printed foil strong adhesion to the image receiving surface. This is a print quality measure.
Considering scratch resistance, it is desirable that each layer of the preprint ribbon is thinner.
Considering this point, it is necessary to determine the preprint ribbon.
It is also possible to enhance the adhesiveness by providing the intermediate layer with a thermosetting material or UV curable material property and completely hardening with heat and UV (ultraviolet light) after printing.
FIG. 9 shows the control device.
The present plan is a control circuit having the same structure as a normal thermal transfer printer (two-head printer).
When the print data and issue command can be sent from the PC via the USB-I / F, the printer side stores the print data in the memory so that it can be easily sent to the thermal head.
・ When the data setting is completed, the printer starts printing. In the case of the present plan, the transport block on which the image receiver is placed moves at a constant speed (1 ″ / S or the like).
When the image receiving member arrives at the place to be printed, the head block 1 lowers the thermal head block, presses the image receiving member, drives the ribbon, and starts printing.
The head block 1 continues printing at certain intervals until printing of one sheet is completed. When finished, the head block is raised and ribbon driving is stopped.
The head block 2 performs the same operation as the head block 1 at the time when the image receiver is conveyed by the distance from the head block 1 and performs foil printing.
-When printing is completed, the transport system returns to the original position and prepares for the next printing.
The end status is sent to the PC side and the next issue data is sent to the PC side.

As an on-demand printing device, for consumer use ・ Clear file logo and company name are printed with gold leaf.
・ The name of the sending plan is printed in gold leaf on the gift certificate.
・ For wedding venues, Japanese paper with gold leaf, for the bridegroom and bridegroom industry ・ RFID antennas printed on demand (copper and AL foil used)
・ Direct printing on industrial materials such as polyolefin and polypropylene.

FIG. 1 is an external view of a commercially available hot stamp. Hot plate method □ Hakuoshi is also known as hot stamping. It is a method of heat-pressing the color coated on the film with heat and pressure as shown in the figure. (This film is a foil.) The biggest feature of foil stamping is that, unlike ordinary printing, it can express a metallic feeling (metallic luster) as a material and has the merit of a dry method that does not use solvents. Its applications are packaging, bookbinding, stationery, cards and electrical appliances. In addition, the label of liquor, T-shirt patterns, and “expiration date” numbers for foods. When you look around the world, it is used to say "Is it here?" The foil to be stamped leaves the base film, and is transferred from the release layer to the adhesive layer. Hot plate foil structure Base film Polyester (PET) having a thickness of 12 to 16 micrometers is often used. It becomes a base material for carrying 2-5. 2. 2. Release layer An extremely thin layer that is activated by heat at the time of foil pressing to make it easy to separate each of layers 3 to 5 from the base film. Colored layer The colored layer expresses color. For gold color, yellow coating. The vapor deposition layer in the third step is a silver metallic color, and appears to be a gold color overlapping with the yellow coating. The strength of the colored layer determines the properties (wear resistance, heat resistance, etc.) after pressing the foil. 4). Vapor deposition layer Use a vacuum vapor deposition machine. The vacuum evaporation machine is equipped with a winding device, a metal melting crucible, and a heat source in a high vacuum machine, and a high vacuum of 0.0001 to 0.0005 m / m mercury column (vacuum unit: atmospheric pressure 760 m / m mercury column). Dissolve and evaporate the aluminum in to deposit the aluminum on the films 1 to 3. In a high vacuum, aluminum flies in molecular form and forms a thin film uniformly on the film. The thickness of the film is said to be 0.03 to 0.05 micrometers (300 to 500 angstroms). This deposited layer expresses a metallic feeling. 5. Adhesive layer Adhesive is applied under the deposited layer. The adhesive is selected according to the material to be transferred. The type of adhesive varies depending on the state of surface processing, such as adhesive that adheres well to paper on paper, adhesive that adheres well to resin on plastic, and the like. The adhesive adheres to the non-transfer material by heat and pressure. The reason for changing the temperature and pressure in use depending on the type of adhesive is to select a temperature and pressure suitable for the properties of the adhesive. Commercially available direct foil printing machine A commercially available printing machine with a single thermal head that prints the foil directly on the receiver. In the case of this apparatus, the thermal head block is an apparatus that moves together with printing. Foil printer structural drawing, head position adjustment device Detailed explanation in the explanation of the embodiment Printing method for hot stamp foil printer Detailed explanation in the description of the examples Preprint printing method Detailed explanation in the description of the embodiment Pre-print ribbon structure Detailed explanation in the example description Control configuration Detailed explanation in the description of the embodiment

Claims (11)

A thermal printer that has two or more thermal heads and a transfer ribbon driving device and has a device for moving a print medium (image receiver) relative to each other, and prints a hot stamping foil on the print medium. A substance that improves the adhesion between the printing medium (image receiver) and the foil is transferred by the first thermal head of the printer, and the foil is printed by the second thermal head on the place where the foil is printed by the first head. The structure of the transfer ribbon to be printed (transferred) in the first thermal head part according to claim 2 is the order of the release layer, the intermediate layer, and the adhesive layer from the substrate side (on the back side of the substrate layer for preventing sticking) With a coating layer), the thickness of the release layer, the thickness of the intermediate layer, the thickness of the adhesive layer, each material, and the melt viscosity, the material of the print medium (image receiver) Selectable by surface roughness, scratch resistance of printed foil. The foil is printed by the second thermal head according to claim 2, and the print pattern can be changed and changed depending on the material and surface roughness of the image receiving member in order to ensure the foil print quality. The thickness of the receiver is from about 0.1 mm to several centimeters. 2. The printer according to claim 1, further comprising a device for ensuring that the pressing force of the thermal head is uniform and within a certain range when printing on these. 6. The printer according to claim 5, wherein the thermal head block itself can be driven up and down, and the pressure can be automatically adjusted by pressing the image receiver from above. A printer in which the adjustment of the thickness of the image receptor is roughly adjusted on the image receptor conveying apparatus side and fine adjustment is made possible by the thermal head block in claim 5 above. A device that uses a pressure sensor to maintain a constant pressure. An apparatus for holding and transporting an image receiving body, including an apparatus for stably holding the image receiving body during printing 9. The surface according to claim 8, wherein the surface of the table on which the image receiving body is placed is provided with a conveying device. 2. The printer according to claim 1, wherein after printing with two heads, in order to improve the scratch resistance and scratch resistance of the foil printing, the printing surface is pressed with a roller or the like and printed strongly on the image receiving surface. It was intended to be. A member using a thermosetting or UV curable material as a member to be printed or transferred by the first head according to claim 2.

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