Thermal transfer printing dyesheet

Details Thermal transfer printing dyesheet Thermal transfer printing dyesheet

1995-05-04

1996-04-23

Hess, B. Hamilton

Record receiver having plural interactive leaves or a colorless

Having plural interactive leaves

428195, 428913, 428914, B41M 5035, B41M 538

Patent

active

055103138

DESCRIPTION:

BRIEF SUMMARY
The invention relates to dyesheets for thermal transfer printing, and especially to dyesheets capable of providing prints with good colour rendition.
Thermal transfer printing is a generic term for processes in which one or more thermally transferable dyes are caused to transfer from a dyesheet to a receiver in response to thermal stimuli. Using a dyesheet comprising a thin substrate supporting a dyecoat containing one or more dyes uniformly spread over an entire printing area of the dyesheet, printing can be effected by heating selected discrete areas of the dyesheet while the dyecoat is pressed against a dye-receptive surface of a receiver sheet, thereby causing dye to transfer to corresponding areas of the receiver. The shape of the pattern transferred is determined by the number and locations of the discrete areas which are subjected to heating. Full colour prints can be produced by printing with different coloured dyecoats sequentially in like manner, and the different coloured dyecoats are usually provided as discrete uniform print-size areas in a repeated sequence along the same dyesheet.
High resolution photograph-like prints can be produced by thermal transfer printing using appropriate printing equipment, such as a programmable thermal print head or laser printer, controlled by electronic signals derived from a video, computer, electronic still camera, or similar signal generating apparatus. A typical thermal print head has a row of tiny selectively energizable heaters, spaced to print six or more pixels per millimeter, often with two heaters per pixel. Laser printers require absorbers to convert the laser radiation to heat, usually in or under the dyecoat, and similarly produce the print by transferring dyes to the receiver pixel by pixel.
Like colour printing of various other technologies, thermal transfer printing is based on a subtractive three colour system, using yellow, magenta and cyan colours (not precluding the addition of black). In addition to their characteristic absorptions in the green, magenta dyes typically provide substantial blue absorption, and cyan dyes typically have substantial absorption of green wavelengths in addition to their characteristic absorption of red light. Yellow dyes absorb in the blue to provide their characteristic colour, and the additional absorptions at shorter wavelengths are generally outside the visible region, so do not contribute to the colour perceived.
Although such dyes may have good colour on their own, when they are mixed to produce other colours, these additional shorter wavelength absorptions can become a problem, in that they can distort the colour rendition obtained. Thus for example, yellow and magenta dyes are combined to produce red, but a high blue absorption by the magenta will provide a yellowness in addition to that of the yellow dye used, with a consequence that the resulting red will be more orange than would otherwise be the case. In addition to a distorted colour balance, the colour rendition can suffer from a dullness, where the colours appear less bright and the prints thereby less appealing.
This phenomenon is neither new nor confined to thermal transfer printing, and various correction techniques have previously been developed in the various different colour reproducing technologies, such as the masking used in conventional colour printing, for example. In thermal transfer printing, colour correction can be obtained by matrixing, a technique in which the control signals to the printer are adjusted for each pixel so as to correct the amount of each dye transferred in a manner and to an extent which compensates for any other corresponding absorption transferred in another dye to that same pixel, either before or subsequently. Thus, using the above example as illustration, the orangeness of the red may be corrected by transferring less of the yellow dye, where it is to be overprinted with the magenta having high absorption in the blue, whereas elsewhere the full amount of yellow is transferred by applying the yellow control signa

REFERENCES:
patent: 203056 (1986-11-01), Polaroid
patent: 270677 (1988-06-01), Dai Nippon
Spencer, D. A., "Color Photography in Practice", London, Pitman and Sons Limited, 3rd ed., Chap. 17, pp. 322-329.
D. A. Spencer "Colour Photography in Practice" 13 Dec. 1948, Sir Isaac Pitman & Sons Limited, London, G.B. 3rd Edition, Chapter 17, pp. 322-329 See p. 323, Line 14-Line 28.

Affiliated with

Also associated with

Rating

Thermal transfer printing dyesheet does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Thermal transfer printing dyesheet, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thermal transfer printing dyesheet will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2308362