Patent ID: 6597385
Filing Date: 2003-07-22
Classification: B41J,H04N

Abstract:
A method for printing an image using a thermal printing system comprising a thermal printer having a thermal head TH incorporating a plurality of energisable heating elements Hn and a thermographic material m, said method comprising the steps ofsupplying image data Id corresponding to a plurality of output values Dk to a processing unit of said thermal printer, reading a first table LUT1 comprising first entries for desired output values Dk and second entries for sequences Sk of time slices si of activation pulses, transformation of said image data Id into corresponding sequences Sk of time slices of activation pulses, wherein said transformation of said image data Id comprises a step of establishing a relation between output values Dkcm which are both continuous and monotone, and corresponding sequences Sk of time slices si of activation pulses, providing said time slices of activation pulses to said heating elements Hn of said thermal head TH, printing said image by transporting said thermographic material past and adjacent to said thermal head and by activating said heating elements Hn of said thermal head, further comprising the substeps of: building a calculation scheme representative for said thermal printing system, said calculation scheme taking into account thermal characteristics of said thermal head TH, thermal characteristics of said thermographic material m, thermal characteristics of a platen and specific heat productions qk as imposed by sequences Sk of said time slices si having different binary weights wi; calculating transient temperature histories Thk in said thermographic material m for said sequences Sk of time slices si having different binary weights wi; establishing a relationship between said transient temperature histories Thk and calculated output values Dhk; storing into a second table LUT2 first entries for continuous and monotone output values Dhkcm and second entries for corresponding sequences Sk.