Print Engine; Sublimation Dye Transfer - The Engine's Printing Technology; The Print Process - Tektronix Phaser 480 Service Manual

Print engine

Sublimation dye transfer — the engine's printing technology

The print process

To make colored prints, the print engine uses a color printing method called
sequential sublimation dye transfer printing . Simply said, the print engine prints by
subliming or vaporizing dots of colored dye from a Mylar® ribbon into a sheet
of paper. The benefits of this method are high-resolution, continuous tone
printing, easy maintenance, and fast printing.
Figure 5-2 illustrates the printing process employed by the print engine. In the
printing process, a single piece of polyester paper (or transparency film) is
drawn past a thin Mylar ribbon, called a transfer roll, which is coated with
sequential bands of colored dye: yellow, magenta and cyan and, in the case of
4-Color Transfer Rolls, black. A heating device, called a thermal head, vaporizes
the colored wax from the transfer roll into the paper. The thermal head is an
electrical device containing 3576 individually controlled heating elements
aligned parallel to the short axis of the paper it prints upon. And because the
row of thermal elements span the width of the page, the print engine prints an
entire line at one time; this accounts for the print engine's fast print time. The
printer uses a special polyester paper which presents an ultra-smooth, flat
surface for the dye to absorb into.
During printing, the print engine moves the paper past the thermal head three
times (or four times for 4-color transfer rolls). During each pass of the paper,
individual thermal head elements sublime tiny dots of dye from the transfer
roll's colored bands; first from the yellow band, then the magenta band, and
finally, cyan. (For 4-Color Transfer Rolls, black is transferred last, after cyan.)
The overlaid colors combine on the paper to produce a complete color image.
After the three passes, the finished copy is ejected from the printer. The dye
transfer roll is supplied on one spool, feeds past the thermal head and drum for
printing, and collects on a take-up spool.
Theory of Operation
Service Manual 5-3
5