Mannesmann Aktiengesellschaft

Francotyp-postalia Ag & Co.

Siemens Aktiengesellschaft

Eastman-kodak Company

Wolfgang Pekruhn

Hartmut Grethen

Oskar Nuyken

Ferdinand Quella

Stephan Guenther

Thomas Gerhardt

Raimund Nisius

Friedrich-Wilhelm Drees

Walter Eiler

Georges Roussos

Friedrich Drees

Ngoc Q Pham

Mohamed Al-Khatib

Hartmut Kirchhoff

Barbara Dorner

Ralf Kaiser

The present invention includes an aqueous ink that has a composition which contains one or more dyestuffs, at least one alkanol with a straight or branched C -C -alkyl chain and between two and four hydroxyl groups, at least one C -C -alkyl ester of an &prop;-hydroxycarboxylic acid of the formula R&mdash;C(OH)&mdash;COOH, wherein R is H or a straight or branched C -C -alkyl residue of a penetration agent, a surfactant, other adjuvants, and wherein the balance of the composition is water.

Aqueous ink and use thereof

An arrangement for monitoring the functioning of an ink print head, an enhancement of the functional dependability by enhancing the monitoring precision given reduced outlay is obtained with a constant monitoring and evaluation of the print format, with the brightness of the recording medium having no influence on the monitoring precision. A sensor head with at least two wiper electrodes is placed on the recording medium following the ink print head and is connected to an evaluation circuit that in turn has an output side connected to the drive circuit for the ink print head. Changes in the electrical properties of the recording medium between the wiper electrodes are acquired in the evaluation circuit, these changes arising due to the presence of just-printed ink thereon. The arrangement is suitable for ink print heads operating according to the bubble jet principle as well as for ink print heads with piezo actuators.

Arrangement for monitoring functioning of an ink print head

Method for operating a recording device powered by at least one

Process for printing a halftone image

Inking ribbon

In a prior art thermal printing method, the heating elements of a thermal printing head are driven in such fashion that the temperature of each and every individual heating element is first measured individually and successively before this heating element is charged with a current pulse whose intensity of current is dimensioned dependent on the measured temperature. In order to increase the printing speed, the temperatures of all heating elements (R1 . . . Rn) are first successively measured in the novel method fo the present invention in every drive cycle and are extrapolated to isochronic cooling temperature values dependent on the cooling characteristic of the heating elements (R1 . . . Rn). The heating elements (R1 . . . Rn) are then charged with current pulses whose pulse durations are individually dimensioned for every heating element (R1 . . . Rn) dependent on the cooling temperature value calculated for this heating element (R1 . . . Rn).

Thermal printing method

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Berlin, Germany

Wolfgang Pekruhn