ADJUSTABLE FORCE SUPPORT ROLLERS FOR A THERMAL PRINTER PLATEN ROLLER
Publication Date: 2004-Mar-31
The IP.com Prior Art Database
The present disclosure relates generally to dye transfer or thermal printers.
The present disclosure relates generally to dye transfer or thermal printers. More particularly, this disclosure relates to the problem of not attaining a uniform pressure required between the necessary components, typically comprised of a stationary liner area (bead) of selectively heated resistive elements on a thermal print head, dye transfer (donor) web, dye receiver medium and platen roller. This non-uniform pressure results in undesireable print quality on the dye receiver medium.
A typical multi-color dye transfer web that is used in a dye transfer or thermal printer is substantially thin and has a repeating series of three different rectangular-shaped color sections or patches such as a yellow color section, a magenta color section and a cyan color section. In addition, there may be a transparent colorless laminating section immediately after the cyan color section.
Each color section of the dye donor web consists of a dye transfer area which is used for dye transfer printing and a pair of opposing lateral edge areas alongside the dye transfer area (running the length of the dye donor web) which often are not used for printing. The dye transfer area may be about 152mm wide and the two longitudinal edge areas may each be about 5.5mm wide, so that the total web width is approximately 163mm.
To make a multi-color image print using a thermal printer, a motorized donor web take-up spool draws a longitudinal portion of the dye donor web off a donor web supply spool in order to successively move an unused single series of yellow, magenta and cyan color sections over a stationary liner area (bead) of selectively heated resistive elements on a thermal print head between the supply and take-up spools. Respective color dyes within the yellow, magenta and cyan color sections are successively heat-transferred line-by-line, via the selectively heated resistive elements, onto a dye receiver medium such as a paper or transparency sheet or roll, to form the color image print. The selectively heated resistive elements often extend across the entire width of a color section, i.e. across the dye transfer area and the two longitudinal edge areas comprising that color section. However, only those resistive elements that contact the dye transfer area are selectively heated. Those resistive elements that contact the two longitudinal edge areas are not heated. Consequently, the dye transfer occurs from the dye transfer area to the dye receiver medium, but not from the two opposing lateral edge areas to the dye receiver medium.
As each color section is drawn over the selectively heated resistive elements, it is subjected to a longitudinal tension particularly by the forward pulling force of the motorized donor web take-up spool. Additionally, to achieve the desired transfer level of dye to the receiver medium, a compressive force is required at the nip between the thermal print head, and plat...