DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a simplified representation of a franking strip with a barcode.
FIG. 2 is a plan view of a simplified thermotransfer print head.
FIG. 3 is a simplified flow chart for processing image data required for printing according to the prior art.
FIG. 4 shows a temperature curve and pulse/time diagram given printing of a dot.
FIG. 5 shows a simplified representation of the barcode data.
FIG. 6 shows a barcode image for explanation of the barcode data preparation using history control.
FIG. 7 shows a barcode image with external regions for explanation of a data preparation that is different for these regions, the external regions serving for pre-heating of heating elements (variant 1).
FIG. 8 is a section through a thermotransfer print head along a row of resistor heating elements.
FIG. 9 is a flow chart for processing image data required for printing in accordance with the invention.
FIG. 10 is block diagram for controlling the printing of a franking machine with a print data controller for a thermotransfer print head.
FIG. 11 is a perspective representation of a commercially available franking machine (Optimail 30 of Francotyp-Postalia GmbH).
FIG. 12 shows a franking imprint according to the DPAG requirement FRANKIT.
FIG. 13 shows program routine with determination of the energy values for preheating and border heating of a thermotransfer print head.
FIG. 14
a shows barcode image with external regions for explanation of data preparation that is different for these regions, the external regions serving for the pre-heating of heating elements (variant 2).
FIG. 14
b shows a franking imprint according to the postal requirements for Australia.
FIG. 14
c is a program routine with determination of the energy values according to a further variant for preheating and boundary heating of a thermotransfer print head (variants 2 and 3).
FIG. 15
a is a pulse/time diagram for activation of a heating element of the thermotransfer print head, which heating element is activated in the leading region B.
FIG. 15
b is a pulse/time diagram for activation of a heating element of the thermotransfer print head, which heating element is situated in the boundary region N1.
FIG. 16 is a sub-routine with determination of the energy values according to the third variant for preheating of a thermotransfer print head.
FIG. 17 is a sub-routine with determination of the energy values according to the second and third variants for preheating of a thermotransfer print head and for pixel energy value calculation.
FIG. 18 shows a barcode image with external regions for explanation of a data preparation that is different for these regions, the external regions serving for the pre-heating of heating elements (variant 3).
FIG. 19 shows a franking imprint according to the postal requirement for Canada.