DEVICE AND METHOD OF TRANSFER PRINTING

Abstract: A device and a method of transfer printing, wherein a flexible sheet (4) is pressed with fluid pressure to a member (1) to be subjected to transfer printing through another member (3) to be transferred so that the member (3) to be transferred may be spread along the surface of the member (1) to be subjected to transfer printing even if the latter (1) is in the three dimensional shape. Thus, easy and sure transfer printing can be applied to even a three-dimensionally shaped member to be subjected to transfer printing.

Description: TECHNICAL FIELD The invention relates to a transferring apparatus and a transferring method as defined in the preamble of claims 1 and 3. The apparatus and method are particularly suited for transferring a pattern to a three-dimensional molded article. BACKGROUND ART Transfer methods are widely utilized to form patterns or characters on the surface of an article such as a household electric appliance, a cosmetic container, ornaments or the like. Fundamentally, a transferring carrier to be used in transferring methods has a construction comprising a transferring layer such as a pattern layer and an adhesive layer formed on a release sheet. The transferring carrier may include a surface protecting layer as necessary or may not include the adhesive layer when the pattern layer has an adhesive property. As transfer methods, roll transfer method or up-down transfer method is well known and utilized. According to these transfer methods, a pressurizing member such as a roller or a member moving vertically presses a heated silicon rubber provided over the transferring carrier against a material to which the pattern is to be transferred. In roll transfer method, the thickness of the silicon rubber is in the range from 10mm to 50mm and the hardness thereof is in the range from 60° to 90°. In up-down transfer method, the thickness of the silicon rubber is in the range from 2 to 5mm and the hardness thereof is in the range from 60° to 90°. However, in these transfer methods, since the contact surface of the silicon rubber serving as a heat source is linear or flat, the configuration of the material to which the pattern of the transferring member is to be transferred is limited to a two-dimensional curved surface or a flat surface. Thus, it is difficult to transfer the pattern of the transferring member to a three-dimensional material. An apparatus and method according to the preamble of claims 1 and 3 is known from JP-Y2 60-004 759. In this prior art apparatus and method the pressurizing chamber on the rear side of the flexible sheet is held at a constant, adjustable pressure during the transfer operation and thus provides a resilient support for the flexible sheet without being active in pressing the sheet against the transferring carrier and material. JP-B2 59-037 234 discloses a wet printing apparatus wherein a wet ink pattern is applied to a flexible sheet or diaphragm for being printed onto a material. Any transferring carrier carrying a pattern layer is not used. It is an object of the invention to provide a transferring apparatus and a transferring method for easily and reliably transferring a pattern layer from a transferring carrier onto a three-dimensionally configured surface of a material. According to the invention this object is solved by the apparatus and method as defined in claims 1 and 3. The dependent claims relate to further advantageous features of the invention. The apparatus and method according to the invention provide two independently controllable means for pressing the pattern layer onto the surface of the material, namely by moving the flexible sheet towards the material (or vice versa), as in the prior art, and by controlling the supply and discharge of fluid into and from the pressurizing chamber. In the transfer operation, after the sheet is pressed against the material, the fluid supply means may supply the fluid to the pressurizing chamber to apply pressure to the sheet, or alternatively the fluid supply means may supply the fluid to the pressurizing chamber so as to pressurize the sheet before the sheet contacts the transferring carrier. In the transferring method, fluid existing between the material and the transferring carrier may be discharged while carrying out the transferring operation. An adhesive layer may be formed on one of the pattern layer and the material before the sheet presses the transferring carrier against the material The "pattern layer" may include a colorless, transparent surface protecting layer for protecting the surface of a material to which a pattern is transferred and a ground adjusting layer serving as a ground when a pattern is formed with a painting brush not by means of a transfer. According to the invention, even if the material has a three-dimensional configuration on its surface, when the sheet presses the transferring carrier against the material, fluid is supplied to the pressurizing chamber of the supporting member so that the sheet and the transferring carrier conform to the surface of the material in a three-dimensional configuration by the fluid pressure and the pattern of the pattern layer of the transferring carrier can be easily and reliably transferred to the material surface in the three-dimensional configuration. In addition, during the transfer, since the suction member sucks gas existing between the material and the transferring carrier, gas does not penetrate into the space between the material and the transferring carrier. Consequently, the transferring carrier is capable of closely contacting the surface of the material and the pattern layer can be finely transferred to the surface of the material. Therefore, even if concave portions are formed on the material to which the pattern of a transferring carrier is to be transferred, the transferring carrier can be brought into close contact with the surface of the concave portions by means of the suction device which sucks gas existing in the concave portions. Thus, the pattern layer is finely transferred to the concave surface of the material. An in-mold transferring apparatus may be used to transfer the pattern of the transferring carrier to the material in a three-dimensional configuration. In such in-mold transferring method, since the transferring carrier must be inserted into a molding die before a transfer is carried out, disadvantageously, the space for placing the transferring member is limited, and further the configuration of the molding die is complicated. The transferring apparatus according to the invention overcomes such disadvantage. According to the invention, even though the material may have a three-dimensional configuration on its surface, when the sheet is pressed against the transferring carrier and the material, the sheet and the transferring carrier are capable of conforming to the surface of the material in a three-dimensional configuration by the fluid pressure. Thus, the pattern of the pattern layer of the transferring carrier can be reliably and easily transferred to the surface of the material having the three-dimensional configuration. In addition, during the transfer, unnecessary gas does not penetrate into the space between the material and the transferring carrier because fluid existing between the material and the transferring carrier is discharged. Consequently, the transferring carrier is capable of closely contacting the surface of the material and the pattern layer can be finely transferred to the surface of the material. Therefore, even if concave portions are formed on the material the transferring carrier can be brought into close contact with the concave surface by discharging fluid in the concave portions. Thus, the pattern layer is finely transferred to the concave surface of the material. BRIEF DESCRIPTION OF THE DRAWINGS These and other objects and features of the present invention will become clear from the following description taken in conjunction with a preferred embodiment thereof with reference to the accompanying drawings, in which: Fig. 1 to 5 are sectional views showing a transferring apparatus according to an embodiment of the present invention in successive stages of a transferring process. BEST MODE FOR CARRYING OUT THE INVENTION The embodiment of the present invention is described in detail below based on Figs. 1 through 5. In order to perform a transfer, in a transferring apparatus of the embodiment, a material 1 to which the pattern of a transferring carrier 3 is to be transferred is placed on a base 2; a heated flexible sheet 4 supported by a supporting member 5 is opposed to the material 1 with the transferring member 3 arranged therebetween; a driving member (not shown) drives the supporting member 5 to move downward toward the base 2; and the sheet 4 presses the transferring carrier 3 against the material 1 as shown in Fig. 2. The upper surface of the base 2 is flat and has many suction holes 2a formed therein and connected with a suction member 12 so that gas existing between the material 1 and the transferring member 3 can be sucked away. The transferring carrier 3 is roll-shaped and comprises a release layer, formed on a release sheet 3b consisting of a base film having release property, which is left on a pattern layer 3a when the release sheet 3b is separated from the pattern layer 3a and functions as a protecting layer of the pattern layer 3a; the pattern layer 3a has a pattern such as pictures thereon; and an adhesive layer is formed on the pattern layer 3a, which are overlapped in this order. The pattern layer 3a may be a multilayer or include a metal evaporating layer. The pattern layer 3a may include a surface protecting layer as necessary. That is, the above-described "pattern layer" may include a colorless, transparent surface protecting layer for protecting the surface of a material 1 to which the pattern of the transferring member is transferred and a ground adjusting layer serving as a ground when a design is formed with a painting brush not by means of a transfer. A feed-out roller 8 and a winding roller 9 are provided, respectively on both sides of a region in which the base 2 and the supporting member 5 are provided in opposition to each other. The roll-shaped transferring carrier 3 is sequentially fed out from the feed-out roller 8 toward the winding roller 9. When a predetermined pattern of the pattern layer 3a is transferred to the material 1, a subsequent pattern of the pattern layer 3a formed on the release sheet 3b is fed out from the feed-out roller 8 by a predetermined pitch while the release sheet 3b removed as a result of the transfer of the pattern layer 3a to the material 1 is rolled round the winding roller 9. The configuration of the transferring carrier 3 is not limited to a roll configuration, but the transferring carrier 3 may be composed of strips of paper which are replaced each time a transfer is performed. The sheet 4 may consist of, for example, a silicon rubber elastically deformable along a three-dimensional configuration of the material 1 and approximately 2mm to 3mm thick. The supporting member 5 supports the sheet 4 on the side facing away from the material 1 by bringing the sheet 4 into close contact with a container 5a thereof. A sheet pressurizing chamber 11 which can be enclosed by the container 5a is formed on the side of the sheet 4 facing away from the material 1. The sheet 4 is heated by heaters 6 provided on the bottom surface of the container 5a. Reference numeral 10 in the drawings denotes a discharge pipe of fluid supplied in the pressurizing chamber 11. Fluid, liquid such as water or oil or gas such as vapor or compressed air is supplied from a fluid supply member 7 into the pressurizing chamber 11 of the supporting member 5, thus supporting the sheet 4 in a pressurized state. The supporting member 5 can be moved toward the material 1 placed on the base 2 or moved away therefrom by a driving member not shown. According to the above-described construction, as shown in Fig. 1, the material 1 is placed on the upper surface of the base 2 and the pattern layer 3a of the transferring carrier 3 which is to be transferred is opposed to the material 1 via the adhesive layer. At this time, the sheet 4 is heated by the heaters 6. Then, as shown in Fig. 2, the supporting member 5 is moved downward so that the sheet 4 allows the transferring carrier 3 to contact the material 1 and the lower end surface of the container 5a of the supporting member 5 is pressed against the upper surface of the base 2 with the sheet 4 interposed. Thereafter, as shown in Fig. 3, fluid is supplied from the fluid supply member 7 into the pressurizing chamber 11 of the supporting member 5 so that pressure is applied to the sheet 4 and the sheet 4 presses the transferring carrier 3 against the upper surface of the material 1. Thus, the sheet 4 and the transferring carrier 3 conform to the three-dimensional configuration of the upper surface of the material 1 and the pattern layer 3a is transferred to the surface of the material 1 in the three-dimensional configuration by heat transmitted from the sheet 4 and the fluid pressure. In this transfer, the suction member 12 sucks fluid such as gas existing between the material 1 and the transferring carrier 3 through the suction holes 2a of the base 2 so that the pattern layer 3a closely contacts the surface of the material 1 via the adhesive layer. Then, the supporting member 5 is moved upward as shown in Fig. 4 after the fluid in the pressurizing chamber 11 is released from the discharge pipe 10. Thereafter, as shown in Fig. 5, the feed-out roller 8 and the winding roller 9 are driven so that the release sheet 3b from which the pattern of the pattern layer 3a has been transferred to the material 1 is separated from the surface of the material 1 so as to roll the release sheet 3b round the winding roller 9 and the subsequent pattern layer 3a is positioned above the base 2. In this state, the release layer separated from the release sheet 3b and a pattern 13 of the pattern layer 3a have been transferred and adhered to the surface of the material 1 through the adhesive layer. The release layer functions as the protecting layer of the pattern layer 3a. According to the above-described embodiment, even though the material has a three-dimensional configuration on its surface, when the sheet 4 presses the transferring carrier 3 against the material 1, fluid is supplied to the pressurizing chamber 11 of the supporting member 4 so that the sheet 4 and the transferring carrier 3 conform to the surface of the material 1 in the three-dimensional configuration by the fluid pressure and the pattern of the pattern layer 3a can be easily and reliably transferred to the surface of the material 1 in the three-dimensional configuration. Accordingly, if a material has a rounded corner, the sheet and the transferring carrier contact each other along the rounded corner to which a pattern is to be transferred. Therefore, the pattern of the transferring carrier can be finely and reliably transferred to the material at the rounded corner. In addition, during the transfer, since the suction member 12 sucks away any gas existing between the material 1 and the transferring carrier 3, unwanted gas does not penetrate into the space between the material 1 and the transferring carrier 3. Consequently, the transferring carrier 3 is capable of closely contacting the surface of the material 1 and the pattern can be finely transferred to the surface of the material 1. Therefore, even if a concave is formed on the material, the transferring carrier 3 can be brought into close contact with the concave surface by the suction device which sucks away any gas existing in the concave. Thus, the pattern of the transferring carrier 3 is finely transferred to the concave surface of the material 1. In-mold transferring method is used to transfer the pattern of the transferring member to the surface of the material in a three-dimensional configuration. The invention is not limited to the above-described embodiment, but various modifications may be made. For example, a similar operation and effect can be brought about by moving the base 2 toward and away from the supporting member 5. It is possible to bring the pressurized sheet 4 into contact with the transferring carrier 3 by supplying fluid to the pressurizing chamber 11 of the supporting member 5 before the sheet 4 contacts the transferring carrier 3. Fluid may be discharged from the pressurizing chamber 11 after the sheet 4 separates from the transferring carrier 3. The sheet 4 and the transferring carrier 3 may be pressed against the material 1 only in the region in which the pattern of the transferring carrier 3 is to be transferred to the material 1. The construction of the transferring carrier 3 is not limited to the above-described one, but may be varied. For example, in the above embodiment, when the release sheet 3b is separated from the material 1, the release layer of the release sheet 3b is left on the pattern layer 3a, thus functioning as a protecting layer of the pattern layer 3a. However, the release sheet 3b may consist of a base film and a release layer so that the release layer is separated from the pattern layer 3a by separating the release sheet 3b from the pattern layer 3a. Preferably, the release layer may consist of the base film and coated resin on the base film or films laminated one on the other. The transferring carrier 3 may be made without an adhesive layer on the pattern layer. That is, the transferring carrier 3 may consist of a release sheet made of a base film, a release layer which is left on the pattern layer when the release sheet is separated from the material; and a pattern layer having adhesive property and patterns. In this case, the pattern layer functions as the adhesive layer. Thus, the construction of the transferring carrier can be simplified due to the non-provision of the adhesive layer. Further, the transferring carrier 3 may consist of a release sheet made of a base film; a release layer which is left on the pattern layer when the release sheet is separated from the material; and a pattern layer having patterns but no adhesive property. In this case an adhesive agent is applied to the pattern layer of the transferring carrier before a transfer is carried out or the pattern of the pattern layer may be transferred to the material after an adhesive tape is adhered to the pattern layer. Alternatively, the transferring carrier 3 may consist of a release sheet made of a base film; a release layer which is left on the pattern layer when the release sheet is separated from the material; and a pattern layer having patterns but no adhesive property. In this construction, the pattern of the pattern layer of the transferring carrier is transferred to the material having an adhesive agent applied thereto or the material having an adhesive tape stuck thereto. In both cases an adhesive agent having a strong adhesive property or a water adhesive agent may be used so that a transfer can be carried out at a low temperature and thermal deformation of the material can be prevented. When an adhesive tape is used, a heating operation can be eliminated in the transfer process.

Claims: A transferring apparatus for transferring a pattern layer from a flexible transferring carrier (3) onto a material (1), comprising: a base (2) for placing said material (1) thereon; a sheet supporting member (5) supporting a flexible sheet (4) opposed to said base (2), said sheet supporting member (5) having a sheet pressurizing chamber (1) on the side of the sheet (4) opposite from said base (1), fluid supply means for supplying fluid into the pressurizing chamber (11) and heating means (6) for heating the fluid, means (8, 9) for holding said flexible transferring carrier (3) between the flexible sheet (4) and a material (1) placed on said base (2), and driving means for moving one of said sheet supporting member (5) and base (2) towards the other for pressing said flexible transferring carrier (3) by means of the flexible sheet (4) onto the material (1) characterized in that said fluid supply means (7) is controllable to start the supply of fluid into the pressurizing chamber (11) at a certain time before or after said sheet supporting member (5) and base (2) are moved towards each other and to discharge the fluid from the pressurizing chamber (11) at a certain time before or after the sheet supporting member (5) and base (2) are moved away from each other. An apparatus as claimed in claim 1, wherein the base (2) has a plurality of suction holes (2a) and a suction member (12) connected thereto for sucking gas through the suction holes (2a) when a transfer is carried out with the transferring carrier (3) contacting the material (1). A transferring method for transferring a pattern layer from a flexible transferring carrier (3) onto a material (1), comprising the steps of: placing the material (1) on a base (2) locating the transferring carrier (3) over a transfer region of the material (1), the transferring carrier (3) having a pattern layer (3a) on the surface of a release sheet (3b) facing the material (1); moving a heated flexible sheet (4) against the side of the flexible transferring carrier (3) facing away from the material (1), thereby pressing the flexible transferring carrier against the material (1) for transferring the pattern onto the material (1) and removing the sheet (4) and the release sheet (3b) of the transferring carrier (3) from the material (1) after the transferring step is completed, characterized in that after moving the flexible transferring carrier (3) against the material (1) by means of the flexible sheet (4), fluid pressure is applied to the sheet (4) for additionally pressing the transferring carrier (3) against the material (1) by means of the sheet (4). A transferring method as claimed in claim 3, wherein gas existing between the material (1) and the transferring carrier (3) is removed by suction when carrying out the transferring operation. A method as claimed in claim 3 or 4, wherein an adhesive layer is formed on a pattern layer (3a) of the transferring carrier (3) or on the material (1) before the transferring carrier (3) is pressed against the material (1) by means of the sheet (4).

Inventors: OKUNO SHIRO, OKUNO, SHIRO, OKUNO, SHIRO, NISSHA PRINTING CO., LTD.
Applicants: NISSHA PRINTING, NISSHA PRINTING CO., LTD.
Application year: 1991
Main classification: B41F16
IPC codes: B41M5, B41F16, B41F17