Abstract: A thermal head printer with image-invariant printing speeds for printing a substantially light-insensitive thermographic material having a print density-driving power level characteristic, the thermal head printer comprising a transport means, one or more thermal heads each having an array of heating elements, a thermal print head drive system capable of supplying power to each of the printing elements, and a calibration means based on the print density-driving power level characteristic of the thermographic material; a process for calibrating a thermal head printer with image-invariant printing speeds, the thermal head printer comprising one or more thermal heads each having an array of heating elements connected to a power supply capable of supplying a given number of heating element driving power levels from 0 to a maximum driving power level number, corresponding to Pmax, to each heating element for printing a substantially light-insensitive thermographic material by image-wise heating the thermographic m

Abstract: A thermal head printer for printing but not perforating a substantially light-insensitive thermographic material, the thermal printer comprising: a transport system having a transport direction, n thermal heads, where n is an integer, each of the thermal heads comprising an array of substantially rectangular energizable heating elements, the heating elements having a length Ln in the transport direction and a pitch Pn between adjacent heating elements, and a means for supplying electrical energy to each of the substantially rectangular energizable heating elements in at least one of the thermal heads, the transport system being capable of transporting the light-insensitive thermographic material in contact or proximity with at least one of the thermal heads, wherein at least one of the thermal heads comprises heating elements for which Ln/Pn is between 0.25 and 0.

Abstract: A thermal head printer with image-invariant printing speeds for printing a substantially light-insensitive thermographic material having a print density-driving power level characteristic, the thermal head printer comprising a transport means, one or more thermal heads each having an array of heating elements, a thermal print head drive system capable of supplying power to each of the printing elements, and a calibration means based on the print density-driving power level characteristic of the thermographic material; a process for calibrating a thermal head printer with image-invariant printing speeds, the thermal head printer comprising one or more thermal heads each having an array of heating elements connected to a power supply capable of supplying a given number of heating element driving power levels from 0 to a maximum driving power level number, corresponding to Pmax, to each heating element for printing a substantially light-insensitive thermographic material by image-wise heating the thermographic m

Abstract: A method for calibrating a thermal printer, having a thermal head incorporating a plurality of energisable heating elements, comprises the step of supplying to the thermal printer a thermographic material m, a plurality of printer data Pi each intended to be recorded as a pixel having a density Di, and default reference values for printing parameters comprising a value Pref for a reference printing power; and the step of printing a calibration pattern for the plurality of printer data Pi, the calibration pattern comprising a multiple step density wedge such that a whole range of a relation Di(Pi) between the printer data Pi and the density Di is covered.

Abstract: A thermal head printer for printing but not perforating a substantially light-insensitive thermographic material, the thermal printer comprising: a transport system having a transport direction, n thermal heads, where n is an integer, each of the thermal heads comprising an array of substantially rectangular energizable heating elements, the heating elements having a length Ln in the transport direction and a pitch Pn between adjacent heating elements, and a means for supplying electrical energy to each of the substantially rectangular energizable heating elements in at least one of the thermal heads, the transport system being capable of transporting the light-insensitive thermographic material in contact or proximity with at least one of the thermal heads, wherein at least one of the thermal heads comprises heating elements for which Ln/Pn is between 0.25 and 0.

Abstract: A method for calibrating a thermal printer, having a thermal head incorporating a plurality of energisable heating elements, comprises the step of supplying to the thermal printer a thermographic material m, a plurality of printer data Pi each intended to be recorded as a pixel having a density Di, and default reference values for printing parameters comprising a value Pref for a reference printing power; and the step of printing a calibration pattern for the plurality of printer data Pi, the calibration pattern comprising a multiple step density wedge such that a whole range of a relation Di (Pi) between the printer data Pi and the density Di is covered.

Abstract: A method for printing by thermal sublimation is provided, comprising the steps of: 1) supplying uncorrected input data I.sub.i,u to a processing unit of a printer having a head with a plurality of heating elements; 2) obtaining density correction means M.sub.i,d for improving across-the-head uneveness according to the steps of: a) activating each heating element with power compensated input data, so that a same time-averaged power is generated in each heating element; b) measuring the printing density of pixels; c) estimating for each heating element the deviation .delta..sub.i of the density from a density aimed at by applying said power; d) calculating for each heating element a density correction means M.sub.i,d taking into account said deviation .delta..sub.i ; e) storing each of said density correction means M.sub.i,d ; 3) combining the respective uncorrected input data I.sub.i,u with the respective density correction means M.sub.i,d ; 4) providing the thus corrected data to the thermal head.

Abstract: Thermal recording comprising the steps of supplying input data I.sub.u to a processing unit (23) of a printer having a thermal head with a plurality of heating elements; storing input data of a line into a buffer memory (24), further called input line data I.sub.l ; converting (25) the data I.sub.l into serial configurated data I.sub.s ; mapping (32) the data I.sub.s with resistance compensation data into power mapped data I.sub.m ; shifting the data I.sub.m into a shift buffer memory (26), further called shifted power mapped data I.sub.m' ; counting (33) a number N.sub.s,on of simultaneously activated heating elements; adapting (34) a strobe duty cycle .delta. (35) in accordance with N.sub.s,on, further called voltage corrected strobe duty cycle .delta..sub.v ; providing (36) the .delta..sub.v and the data I.sub.m' to the heating elements for reproducing the line of an image.

Abstract: A thermal dye transfer printing process for making transparent prints, which comprises bringing a dye-bearing donor ribbon (17) in contact with a dye-receiving polymer print sheet (15) at a print zone, supporting both materials on a backing support (14) in said zone and contacting the donor ribbon with a print head (18) for image-wise heating the ribbon and cause dye transfer to the print sheet, wherein the rear side of the print sheet is uniformly heated on a drum (30) after removal of the sheet from the backing support, thereby to reduce curling of the sheet caused by the image-wise heating of its front side.

Abstract: A thermal sublimation printer comprises means for counting at periodic observation times the number (N.sub.h) of activated heating elements; means for measuring at periodic observation times the temperature (T.sub.d) of the drum and the temperature (T.sub.h) of the heatsink; means for digitising the measured temperature of the drum and the measured temperature of the heatsink; means for transferring the number of activated heating elements and the digitised temperature values T.sub.d and T.sub.h ; a device for estimating the temperature (T.sub.e) of the heating elements based on the values of N.sub.h, T.sub.d and T.sub.h ; memory means for storing the estimate of the temperature of the heating elements; the printer operating to adjust the applied energy as a function of the estimate of the temperature of the heating elements and of the required temperature of the heating elements.