WO2008149108A1 - Impression par transfert thermique - Google Patents

Impression par transfert thermique Download PDF

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Publication number
WO2008149108A1
WO2008149108A1 PCT/GB2008/001952 GB2008001952W WO2008149108A1 WO 2008149108 A1 WO2008149108 A1 WO 2008149108A1 GB 2008001952 W GB2008001952 W GB 2008001952W WO 2008149108 A1 WO2008149108 A1 WO 2008149108A1
Authority
WO
WIPO (PCT)
Prior art keywords
vacuum
sheet
article
range
printed
Prior art date
Application number
PCT/GB2008/001952
Other languages
English (en)
Inventor
Jeffrey Michael Howell
Peter Charles William Butcher
Original Assignee
Imperial Chemical Industries Plc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Imperial Chemical Industries Plc filed Critical Imperial Chemical Industries Plc
Publication of WO2008149108A1 publication Critical patent/WO2008149108A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
    • B41M5/025—Duplicating or marking methods; Sheet materials for use therein by transferring ink from the master sheet
    • B41M5/035—Duplicating or marking methods; Sheet materials for use therein by transferring ink from the master sheet by sublimation or volatilisation of pre-printed design, e.g. sublistatic
    • B41M5/0358—Duplicating or marking methods; Sheet materials for use therein by transferring ink from the master sheet by sublimation or volatilisation of pre-printed design, e.g. sublistatic characterised by the mechanisms or artifacts to obtain the transfer, e.g. the heating means, the pressure means or the transport means

Definitions

  • This invention relates to thermal transfer printing, and concerns apparatus for thermal transfer printing of an image from a retransfer intermediate sheet onto an article, a method of printing and an article bearing a printed image.
  • Thermal retransfer printing involves forming an image (in reverse) on a retransfer intermediate sheet using one or more thermally transferable dyes. The image is then thermally transferred to a surface of an article by bringing the image into contact with the article surface and applying heat and possibly also pressure.
  • Thermal transfer printing is particularly useful for printing onto articles that are not readily susceptible of being printed on directly, particularly three dimensional objects.
  • Thermal retransfer printing by dye diffusion thermal transfer printing, using sublimation dyes is disclosed, e.g., in WO 98/02315 and WO 02/096661.
  • the sheet is typically preheated, e.g. to a temperature in the range 80 to 17O 0 C, prior to application to the article, to soften the sheet and render it deformable.
  • the softened sheet is then in a condition in which it can be easily applied to and conform to the contours of an article. This is conveniently effected by application of a vacuum to cause the softened sheet to mould to the article. While the sheet is maintained in contact with the article, e.g.
  • a suitable temperature for dye transfer typically a temperature in the range 140 to 200 0 C, for a suitable time, typically in the range 15 to 150 seconds.
  • a suitable temperature for dye transfer typically a temperature in the range 140 to 200 0 C
  • a suitable time typically in the range 15 to 150 seconds.
  • the article is allowed or caused to cool before removal of the retransfer intermediate sheet.
  • Suitable apparatus for performing the retransfer printing step is disclosed e.g. in WO 01/96123 and WO 2004/022354.
  • a sufficiently high vacuum is used so that the preheated softened sheet moulds around the article without leaving a film of entrapped air which would result in unprinted regions of the article as dye does not diffuse readily through air.
  • Typical vacuum levels are in the range 33-50 kPa (10 to 15 inches Hg) below atmospheric.
  • vacuum levels may also cause undesirable distortion of the softened sheet and possibly puncturing thereof during the initial moulding phase, and additionally may trap pockets of air within concavities by sealing the sheet around the edges of the concavities.
  • JP 6- 115123 discloses thermal transfer printing in a vacuum chamber, using a squeegee to push out air from between a transfer film adhered to an article under low vacuum.
  • the apparatus can therefore only be used with articles of a very restricted range of shapes.
  • the technique does not involve preheating of the film prior to contact with the article.
  • the present invention provides vacuum press apparatus for thermal transfer printing of an image from a thermal retransfer sheet onto an article, wherein the apparatus includes vacuum means for generating variable vacuum levels therein, including low vacuum levels in the range 3 to 7 kPa below atmospheric and high vacuum levels in the range 30 to 85 kPa below atmospheric; and heating means for preheating the sheet.
  • the apparatus By being able to generate variable vacuum levels, it is possible to use the apparatus by initially exposing a preheated softened sheet to a low vacuum level (in the range 3 to 7 kPa below atmospheric). Such low vacuum levels promote gentle progressive stretching of the sheet, which minimises distortion and the risk of puncturing. This low vacuum level thus acts to bring the sheet into loose contact with the article without adherence thereto.
  • the vacuum can be increased to a high level (in the range 30 to 85 kPa below atmospheric) which acts to bring' the sheet into intimate contact with the article leaving no pockets of entrapped air and thus permitting dye diffusion and printing over the full area of the article.
  • the means for generating variable vacuum levels may take a number of possible forms, as will be known to those skilled in the art.
  • the apparatus may comprise a single vacuum pump, with two bleed valves, one for generating low vacuum levels and the other for generating high vacuum levels.
  • the apparatus may alternatively comprise two vacuum pumps, one for generating low vacuum levels and the other for generating high vacuum levels.
  • the apparatus may comprise a vacuum regulator with two set points.
  • the apparatus may otherwise be of conventional construction and may be used in conventional manner.
  • the apparatus includes heating means for preheating the sheet, (typically to a temperature in the range 80 to 170 0 C) to soften the sheet prior to contact with the article.
  • the apparatus suitably also includes heating means for heating the sheet (typically to a temperature in the range 120 to 24O 0 C, commonly about 16O 0 C) to cause dye transfer.
  • the heating means conveniently produces a flow of hot air, to cause uniform heating of the sheet.
  • the apparatus typically includes a support for holding one or more articles to be printed, including optional nests or moulds shaped to be complementary to the items to be printed on, to act as a support therefor and prevent distortion of items such as thin-walled plastics articles that might otherwise distort on heating.
  • the apparatus suitably includes means for holding a thermal retransfer sheet in position, over an article to be printed on.
  • Means are desirably provided for causing relative movement between the article and sheet, to bring the sheet (in softened condition after preheating) and article into contact, with the support conveniently including elevating means for raising and lowering the support.
  • the apparatus conveniently includes cooling means, typically in the form of a fan for directing a flow of cold air over the article and sheet after printing for cooling both.
  • cooling means typically in the form of a fan for directing a flow of cold air over the article and sheet after printing for cooling both.
  • the apparatus suitably includes computer control means for regulating operation of the vacuum means, heating means, cooling means and elevating means.
  • the control means may include a number of preset programs suitable for printing a variety of different materials, and may also be programmable by a user to suit other requirements.
  • the apparatus can be used to print images onto articles made of a wide range of materials including plastics, metal, ceramics, wood, composite materials etc. with the articles being of solid or thin- walled construction. Depending on the nature of the surface of the article on which the image is to be printed, it may be appropriate to pre-treat the surface by application of a surface coating or lacquer to improve the take up of transferred dyes.
  • the apparatus is particularly intended for printing onto 3D articles, possibly having complex shapes including curved shapes (concave or convex) including compound curves.
  • Suitable thermal retransfer sheets are commercially available, such as Pictaflex media (Pictaflex is a Trade Mark) from ICI Imagedata.
  • Images may be formed on the retransfer sheet by printing with suitable thermally transferrable dyes, preferably by inkjet printing. Suitable dyes are licensed by Sawgrass Inc.
  • the present invention provides a method of printing an image from a thermal retransfer sheet onto an article, comprising preheating the sheet, causing the preheated sheet to contact the article by exposure to a vacuum at a first, lower level, increasing the vacuum to a second, higher level, and heating the sheet to cause dye transfer from the sheet to the article.
  • the method typically includes a final cooling step.
  • the first vacuum level is preferably in the range 3 to 7 kpa (e.g. 7kPa) below atmospheric and the second vacuum level is preferably in the range 30 to 85 kPa (e.g. about 50 kPa) below atmospheric.
  • the method may include an optional step of preheating the articles. Preheating of the articles is typically at a temperature in the range 100 to 120 0 C for about 30 seconds, with conditions depending on the material of the surface of the article to be printed.
  • Preheating of the sheet is typically at a temperature in the range 80 to 17O 0 C for up to about 30 seconds, with a temperature of about 16O 0 C for 10 seconds or about 130°C for 30 seconds being suitable for Pictaflex media.
  • Preheating of the sheet is desirably achieved by exposure of the sheet to a flow of hot air, causing uniform heating.
  • Dye transfer is typically effected by heating at a temperature in the range 120 to 24O 0 C, commonly about 16O 0 C, for a time in the range 15 seconds to 5 minutes, with conditions depending on factors including the dyes, film and article surface.
  • the first vacuum level is suitably held for about 20 seconds or about 10 seconds.
  • the vacuum level is suitably increased at or around the time when the temperature is increased, if necessary, for dye transfer.
  • the vacuum level may be increased slightly before, slightly after or at the same time as increasing the temperature, if necessary, with optimum operating conditions depending on circumstances.
  • the invention also includes within its scope an article bearing a printed image produced by the apparatus or method of the invention.
  • FIG. 1 and 2 are perspective drawings of the vacuum press
  • Figure 3 is a schematic sectional view of internal components of the press.
  • Figures 4 to 6 are schematic sectional views of internal components of the press at different stages in operation.
  • the illustrated vacuum press 10 is in the form of an A3 format desktop unit designed for use with an A3 retransfer sheet.
  • the press is of generally cuboid shape, with overall dimensions of 800 mm depth, 600 mm height and 600 mm width.
  • the press comprises a housing having a base unit 12 and a lid unit 14 hingedly connected thereto at the rear, with the lid unit being movable manually between an initial open position (as shown in Figure 1) and a closed position for use (as shown in Figure 2).
  • the base unit includes a recess 16 in which is located a table 18 for receiving an array of 3D articles to be printed on or decorated. Resting on table 18 is a nest plate 20 of porous aluminium or fibre carrying an array of nests or moulds 22 (only one of which is shown for simplicity in Figures 3 to 6) shaped to be complementary to the items to be printed on, to act as a support therefor and prevent distortion of items such as thin-walled plastics articles that might otherwise occur on heating. A peripheral rubber seal 24 is provided on the upper surface of the nest plate 20 to seal within the base unit.
  • Table 18 can be raised and lowered on a shaft 26 by a lifting cylinder mechanism (not shown) from an initial lowered position (as shown in Figures 1, 3 and 4) to a raised position (as shown in Figures 5 to 6).
  • the periphery of the recess 16 is surrounded by linear film guides 27 (visible in Figure 1) for accurately locating an A3 retransfer sheet in position over the recess and retaining the sheet in position, resting on a peripheral rubber seal 28.
  • the base unit 12 includes a vacuum system including a vacuum pump and bleed valve (not shown) for generating a vacuum in a flexible hose 30 that passes through table 18 to draw air out from immediately beneath the nest plate 20 .
  • the vacuum system is capable of operating at a low level, in the range 3 to 7 kPa below atmospheric, and a high level, in the range 30 to 85 kPa below atmospheric, and includes a vacuum pump and 2 bleed valves, one for low vacuum levels and the other for high vacuum levels.
  • the base unit also includes a cooling fan 32 with associated electric motor.
  • the lid unit 14 includes a recess 34 the periphery of which is surrounded by a rubber seal 36 that cooperates with the seal 28 of the base unit to secure and seal a retransfer sheet 38 therebetween in the housing when the lid unit is in the closed position.
  • Magnetic locks 39 visible in Figure 1 are provided for securing the lid unit in the closed position.
  • the lid unit 14 includes heating means comprising a fan 40 with associated motor 42 and downstream electrical heater elements 44 for directing a flow of hot air downwardly in the lid unit, with the air passing upwardly through channels 46 to be recirculated within the housing.
  • heating means comprising a fan 40 with associated motor 42 and downstream electrical heater elements 44 for directing a flow of hot air downwardly in the lid unit, with the air passing upwardly through channels 46 to be recirculated within the housing.
  • the apparatus includes computer control means (not shown) and a control panel 50 including display means at the front of the base unit, visible in Figures 1 and 2.
  • an image to be printed on a 3D article is printed (in reverse) onto a suitable retransfer intermediate sheet 38.
  • an image is printed onto Pictaflex A3+ roll media from ICI Imagedata (Pictaflex is a Trade Mark) by an inkjet printing process on an Epson 4400 printer (Epson is a Trade Mark) using Artainium dye sublimation inks (Artainium is a Trade Mark), cut to A3 sheet size and allowed to dry.
  • the lid unit 14 is moved manually to the closed position.
  • the heating means is activated in an article preheating step, with the fan 40 causing hot air at a temperature of about HO 0 C to be recirculated within the housing for about 30 seconds. This acts to preheat the articles to be decorated.
  • the lid unit 14 is then manually moved to the open position.
  • the printed A3 Pictaflex film sheet 38 is placed in position on the base unit 12 over recess 16 within the guides and resting on the seal 28, with the printed side facing the article.
  • the lid unit is manually moved to the closed position, being retained by the magnetic lock, sealing sheet 38 in position between seals 28 and seals 36, as shown in Figures 3 and 4.
  • the heating means is activated, with the fan causing hot air at a temperature of about 16O 0 C to be recirculated within the apparatus for about 10 seconds, resulting in uniform heating of the sheet. At this temperature the film sheet 38 softens and becomes viscoelastic.
  • the table 18 While maintaining heating, the table 18 is raised so that article 52 passes through the softened film 38, as shown in Figure 5, with the film being loosely draped around the article.
  • a vacuum step while maintaining heating the vacuum system in the base unit 12 is then operated, generating an initial low level vacuum of 2 inches Hg (about 7 kPa) below atmospheric (represented by the low vacuum line shown in Figure 5) beneath the film, via hose 30, which acts to draw the film against the article, as shown in Figure 5, with the seals 24 and 28 acting to maintain a vacuum.
  • the softened film conforms loosely to the shape of the article 52.
  • the vacuum level is increased to a high level of 15 inches Hg (about 50 kPa) below atmospheric (represented by the high vacuum line in Figure 6), resulting in the film being brought into intimate contact with the article leaving no pockets of entrapped air.
  • dye diffuses from the film into the adjacent surface of the article, resulting in printing over the full area of the article in contact with the film.
  • the initial low level of vacuum is applied to bring the sheet and article into loose contact.
  • the heat progressively softens the sheet, allowing the sheet to take the general shape of the article and drawing out most of the air.
  • the low vacuum promotes gentle progressive stretch which minimises distortion and the risk of puncturing the soft sheet.
  • the vacuum is increased to the higher level to bring the parts into intimate contact and allow solid state diffusion to take place.
  • the high vacuum ensures that there is no air trapped between the surfaces, through which the dye does not diffuse readily.
  • the table 18 is lowered after an appropriate time, and the vacuum released.
  • cold air is blown upwardly in the base unit 12 by the cooling fan 32 for about 20 seconds to impinge on the articles 52 from below. This acts to cool the articles and sheet.
  • the lid unit 14 is then manually moved to the open position.
  • the film sheet 38 is removed and discarded and the articles 52 removed.
  • the apparatus includes a number of preset programs suitable for a printing a variety of different materials, and is also programmable by a user to suit other requirements.
  • test piece was constructed from a cylindrical open-ended cardboard tube, of diameter 45mm, length 65mm and wall thickness 2mm. This tube was placed on the table 18 of the vacuum press 10, with the axis vertical, so that during the decoration cycle, the film would be drawn down into the tube. Thermal retransfer printing was carried out as described above.
  • Part preheat none.
  • Dual vacuum Low vacuum 20 seconds at 3 kPa. High vacuum 40 seconds at 50 kPa.

Landscapes

  • Decoration By Transfer Pictures (AREA)

Abstract

La présente invention concerne un appareil à presse à vide pour l'impression par transfert thermique d'une image sur un article à partir d'une feuille de retransfert thermique. Cet appareil comporte des organes à faire le vide permettant de produire dans l'appareil des niveaux de vides, et notamment des faibles niveaux de vide dans la plage des 3 à 7 kPa sous la pression atmosphérique, et des niveaux élevés de vide dans la plage des 30 à 85 kPa sous la pression atmosphérique. L'invention concerne également un procédé d'impression d'une image, et l'article imprimé obtenu.
PCT/GB2008/001952 2007-06-08 2008-06-06 Impression par transfert thermique WO2008149108A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0711047.1 2007-06-08
GB0711047A GB0711047D0 (en) 2007-06-08 2007-06-08 Thermal transfer printing

Publications (1)

Publication Number Publication Date
WO2008149108A1 true WO2008149108A1 (fr) 2008-12-11

Family

ID=38318990

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2008/001952 WO2008149108A1 (fr) 2007-06-08 2008-06-06 Impression par transfert thermique

Country Status (2)

Country Link
GB (1) GB0711047D0 (fr)
WO (1) WO2008149108A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2353879A1 (fr) * 2010-02-09 2011-08-10 Alcan Packaging Beauty Services Procédé de non-contact pour la décoration de fibres perméables aux colorants d'un applicateur de cosmétique
EP3722097A1 (fr) * 2019-04-08 2020-10-14 Industrias Samar't, S.A. Procédé de fabrication et de peinture de caractères formés par pressage sur des plaques d'immatriculation et film tubulaire de transfert thermique pour effectuer ledit procédé

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06115123A (ja) * 1992-10-06 1994-04-26 Hoei Fuji Kogyo Kk 熱転写方法
WO2001096123A1 (fr) * 2000-06-15 2001-12-20 E-Comeleon Limited Procede permettant d'imprimer une image sur une surface tridimensionnelle
WO2002072301A1 (fr) * 2001-03-14 2002-09-19 Key-Tech, Inc. Procede et dispositif servant a imprimer une image coloree sur un objet tridimensionnel
WO2004022354A1 (fr) * 2002-09-07 2004-03-18 E-Comeleon Limited Procede et appareil permettant d'imprimer une image sur une surface tridimensionnelle
WO2006050902A2 (fr) * 2004-11-12 2006-05-18 Lasa Impianti S.R.L. Procede et equipement de decoration d'objets par sublimation d'encres
WO2007049070A1 (fr) * 2005-10-24 2007-05-03 Peter John Hoggard Procédé et appareil pour une impression par sublimation

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06115123A (ja) * 1992-10-06 1994-04-26 Hoei Fuji Kogyo Kk 熱転写方法
WO2001096123A1 (fr) * 2000-06-15 2001-12-20 E-Comeleon Limited Procede permettant d'imprimer une image sur une surface tridimensionnelle
WO2002072301A1 (fr) * 2001-03-14 2002-09-19 Key-Tech, Inc. Procede et dispositif servant a imprimer une image coloree sur un objet tridimensionnel
WO2004022354A1 (fr) * 2002-09-07 2004-03-18 E-Comeleon Limited Procede et appareil permettant d'imprimer une image sur une surface tridimensionnelle
WO2006050902A2 (fr) * 2004-11-12 2006-05-18 Lasa Impianti S.R.L. Procede et equipement de decoration d'objets par sublimation d'encres
WO2007049070A1 (fr) * 2005-10-24 2007-05-03 Peter John Hoggard Procédé et appareil pour une impression par sublimation

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2353879A1 (fr) * 2010-02-09 2011-08-10 Alcan Packaging Beauty Services Procédé de non-contact pour la décoration de fibres perméables aux colorants d'un applicateur de cosmétique
EP3722097A1 (fr) * 2019-04-08 2020-10-14 Industrias Samar't, S.A. Procédé de fabrication et de peinture de caractères formés par pressage sur des plaques d'immatriculation et film tubulaire de transfert thermique pour effectuer ledit procédé

Also Published As

Publication number Publication date
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