GB2308097A

GB2308097A - Textile Printing System

Info

Publication number: GB2308097A
Application number: GB9525709A
Authority: GB
Inventors: David Anthony Hulland; Murray Mckerchar
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-12-15
Filing date: 1995-12-15
Publication date: 1997-06-18
Anticipated expiration: 2015-12-15
Also published as: GB9525709D0; GB2308097B

Description

TEXTILE PRINTING SYSTEM The present invention relates to processes for transferring designs from a carrier to a textile fabric and the like using a heat transfer process step.

A typical prior art transfer process for printing and transferring a design onto a fabric or textile involves the steps of: printing (eg. by dry copying) the requisite design onto a silicone- or low density polyethylene (LDPE)-coated carrier paper; bringing the carrier paper into contact with the textile to which the design is to be transferred under conditions of moderate temperature and pressure; and thereby transferring the design printed on the carrier paper to the textile by transfer of the printed inks and a carrier film, into the textile.

This technique is widely applied to a number of different types of fabric or textile. The technique is widely used to transfer a single design to a predetermined position of a single article, such as a T-shirt, by positioning the carrier paper in the desired location on the article, and carrying out the transfer process thereon.

The silicone or LDPE is typically required as a release agent or carrier film to assist in the transfer of the inks from the carrier paper into the textile. However, release agents or carrier films tend to have an undesirable property in that they are also transferred to the textile or fabric being printed. Although LDPE has previously been identified as offering an improvement over release agents such as silicone, the release agents typically modify the tactile presentation or "feel" of the fabric after the transfer process. This is readily perceptible to the end-user of the fabric who generally regards the feel of the fabric as degraded or impaired. This is, of course, particularly detrimental to high quality fabrics.

The prior art has typically addressed this problem by seeking to use different release agents in attempts to minimize the degradation of the feel of the fabric.

According to one aspect of the present invention, it has been recognized that there are a large number of fabrics produced with designs which comprise small repeating areas of the design (eg. patterns or motifs) which are separated by significantly larger "background" areas which are unprinted. This may be described as a pattern plus background type design. In other words, the actual printed and transferred area only comprises a small percentage of the total area of the fabric. Throughout the present specification, these will be referred to as "intermittent" designs, which is generally to be construed to include all designs in which there is a printed area in combination with a substantial area of unprinted background. It would be most advantageous if release agent was not applied to the "background" area: only to the area to be printed and transferred.

As indicated above, prior art processes have typically used a carrier paper which is pre-treated by impregnation with, or by a continuous coat of, the release agent. This carrier paper is typically suitable for use with dry copy processes such as photocopying. This has often placed restrictions on the minimum density of carrier paper being used, in particular with respect to certain types of release agent or copying processes.

According to a further aspect of the present invention, the carrier paper is coated with release agent only in the specific areas being printed, thereby minimizing the area of fabric which will receive release agent during the transfer process.

The term "release agent" is used in the present specification in a general sense to include all chemicals applied to a carrier paper to provide or assist effective transfer of inks printed on the carrier paper from the carrier paper into a fabric, by film transfer or otherwise The term is intended to include carrier films, or those chemicals which assist in release from the carrier paper and fixing agents or those which assist absorption and/or retention of the ink by the receiving fabric. A preferred release agent is LDPE. In some instances, the LDPE may be required as a binding agent to assist in the binding of the ink to the fibres of the textile.

The term carrier paper is used in the present specification to include any suitable flexible carrier medium known in the art for the purpose of transferring a printed design to a fabric.

According to one aspect, the present invention provides a method of transferring an intermittent design to a fabric comprising the steps of: printing the design onto a face of a carrier paper to generate ink areas and non-ink areas; coating said face of the carrier paper with a layer of release agent only in the ink areas of the carrier paper; transferring the ink to the fabric by bringing said face of the carrier paper into pressure contact with the fabric under predetermined temperature conditions.

According to a further aspect, the present invention provides a carrier paper for transferring an intermittent design to a fabric, comprising: a design printed onto a face of the carrier paper, including inked areas and non-inked areas; a layer of release agent co-extensive with substantially only the inked areas.

Embodiments of the present invention will now be described in detail, by way of example, and with reference to the accompanying drawings in which: Figure 1 shows a perspective view of a roll of textile bearing a pattern or motif on blank background design particularly suited to use of the present invention; Figures 2a and 2b show schematic cross-sectional views through a part of a carrier paper suitable for transferring the design of figure 1 to the textile, showing the arrangement of layers used; Figure 3 shows a schematic diagram of a typical transfer calendar suitable for use in carrying out the invention.

With reference to figure 1, there is shown a roll of textile material 10 having a design motif which renders it ideally suited to the present invention. Textile 10 may be previously dyed prior to carrying out the transfer process of the present invention, to provide a desired colour of background area 12. A large number of design motifs 14 are dispersed at regular intervals, in accordance with a predetermined pattern, across the surface area of the textile 10, thereby defining an "intermittent" pattern.

The total area of textile occupied by the design motifs 14 comprises only a percentage of the total background area 12. In most intermittent designs, the area of textile occupied by the pattern or motifs 14 is substantially less than 50%, and typically less than 10%.

Throughout the present specification, the areas of the textile 10 which are to have the printed design transferred thereto are referred to as the ink areas. The background areas, to which no printed ink will be transferred, are referred to as the non-ink areas. It will be understood that the term "ink" is used in a broad context to refer to any chemical to be transferred from a carrier paper to the textile in order to obtain a visible pattern on the textile.

The present invention is particularly suited to transfer processes which can be applied to a long, but finite roll 16 of textile 10 which, for the purpose of this description, will be described as substantially continuous. In this context, the carrier paper can be, at least in a width dimension, of similar size to the textile thereby enabling precise registration of the carrier paper to the textile. Alternatively, one lateral edge of the carrier paper can be adapted to be registered with a corresponding lateral edge of the textile, enabling precise location of pattern or motifs on the textile, notwithstanding that the pattern or motifs may be remote from the lateral edge of the textile and carrier paper.

With reference to figures 2a and 2b, there is shown a carrier paper 20 according to the present invention. The carrier paper 20 is not pretreated with any release agent, and is prepared by first depositing a layer of release agent 22 at every location which will subsequently receive the ink of a printed design. The deposition process preferably comprises standard printing processes well known in the art. According to a presently preferred embodiment, the release agent is printed onto the carrier paper using a Helio Gravure printing machine, in a process to be described hereinafter.

All other areas of the carrier paper 20 will be left without release agent.

On top of the printed release agent 22 will be deposited, again by suitable known printing processes, suitable ink layers 24 for transfer to the textile 10. It will be understood that multiple layers of ink may be used, or several different colours of ink in different places of the ink areas.

According to a presently preferred embodiment, the inks are printed onto the carrier paper 20 using a Helio Gravure printing machine, in a process to be described hereinafter.

As an alternative, the carrier paper 20 may have the ink layer or layers 24 deposited onto the carrier paper 20 prior to depositing the release agent layer 22. In other words, the layers 22 and 24 are reversed.

It will be understood that the registration of the release agent pattern 22 to the various ink patterns 24 may be as accurate as the printing or deposition processes can allow, but that suitable slight oversizing of the areas of the release agent may be required to ensure correct coverage.

Similarly, with reference to figure 2b, in designs in which individual motifs include small areas 30 which are not covered by the ink or inks 24, it may be desirable to deposit the release agent 22 onto an area substantially defined by or close to the approximate outer peripheral edge of the motif or pattern, disregarding any small scale features of this outer edge or gaps in the ink. In the illustration, this includes deposition of release agent 22 between the individual ink tracks 24, but not between motifs.

With reference to figure 3, there is shown a presently preferred printing calender 40 for generating a carrier paper with the requisite printed design and release agent.

The printing calender includes a carrier paper feed 41, a plurality of printing stations 42,44 and a corresponding plurality of intermediate drying stations 46,48 situated between printing stations. The number of stations shown is exemplary only. Carrier paper 20 is fed into the printing calender 40 at paper feed 41, and by the action of rollers 51, 52, is tensioned around a continuous inked print drum 50 which prints the required pattern of ink onto the carrier paper 20 in manner well known in the art. The carrier paper 20 then passes into the drying station 46 before arriving at the second printing station 44. The process is then repeated for each printing station as required. In the preferred embodiments, the first or the last printing station applies the release agent 22 in the requisite pattern which matches the ink pattern 24.

A continuous roll of carrier paper 20 may then be used to transfer the design to a continuous roll of textile material 10, using similar equipment. In this case, the carrier paper 20 and textile material 10 are both fed around a heated drum, between the outer surface of the drum and a tensioned belt which surrounds a large part of the surface of the drum.

The drum rotates on its axis at a speed which corresponds with the speed of the carrier paper and textile passing around the drum, and to the speed of the belt travelling around and past the drum. The speed is adapted to ensure that the carrier paper and textile are held in contact with one another at the correct pressure provided by the tensioned belt and at the correct temperature determined by the drum, for a predetermined period of time. During this predetermined period of time, the printed design on the carrier paper is transferred to the textile.

Claims

1. A method of transferring an intermittent design to a fabric comprising the steps of: printing the design onto a face of a carrier paper to generate ink areas and non-ink areas; coating said face of the carrier paper with a layer of release agent substantially only in the ink areas of the carrier paper; transferring the ink to the fabric by bringing said face of the carrier paper into pressure contact with the fabric under predetermined temperature conditions.

2. A method according to claim 1 in which the non-ink areas are greater in extent than the ink areas.

3. A method according to claim 1 or claim 2 in which the printing process takes place prior to the coating process.

4. A method according to claim 1 or claim 2 in which the coating process takes place prior to the printing process.

5. A method according to any preceding claim including the steps of using a carrier paper which is a substantially continuous roll, and carrying out the transferring process on a heated drum of a transfer calender.

6. A method according to any preceding claim in which the printing and coating steps are carried out on a helio gravure printing machine.

7. A method according to claim 6 in which the printing step includes multiple steps each including different coloured inks and with a drying step between each one.

8. A method according to any preceding claim in which the release agent is LDPE.

9. A method according to any preceding claim in which the ink in inked areas of the design is placed into position on the textile by registering at least one edge of the carrier paper to a corresponding at least one edge of the fabric.

10. A method according to claim 9 in which the inked areas are remote from the registered edges.

11. A carrier paper for transferring an intermittent design to a fabric, comprising: a design printed onto a face of the carrier paper, including inked areas and non-inked areas; a layer of release agent co-extensive with substantially only the inked areas.

12. A carrier paper according to claim 11 in which the non-inked areas are greater in extent that the inked areas.

13. A carrier paper according to claim 11 or claim 12 in which the layer of release agent overlies the ink.

14. A carrier paper according to claim 11 or claim 12 in which the layer of release agent underlies the ink.

15. A carrier paper according to any one of claims 11 to 14 in which the layer of release agent comprises LDPE.

16. A method of manufacturing a carrier paper for transferring an intermittent design to a fabric including the steps of: printing the design onto a face of the carrier paper to include ink and non-ink areas; printing a layer of release agent onto the carrier paper to be coextensive substantially only with the ink areas.

17. The method of claim 16 carried out at different stations of a multistation Helio Gravure printing machine.

18. A carrier paper substantially as described herein and with reference to the accompanying drawings.

19. A method of transferring an intermittent design to a fabric substantially as described herein and with reference to the accompanying drawings.