Abstract: The invention concerns a device for checking the operation of a unit comprising an ink reservoir (112) connected to at least an ink transfer means (113, 204), for an image transfer device (10), characterized in that it includes a means (205, 31, 230) for transmitting energy to ink contained in the ink transfer means, and a means (115, 100) for analyzing the energy transmitted to the ink, with a view to checking the operation of said unit.

Abstract: According to a first aspect, the invention relates to the transmission of an "initial" sequence of at most 2.sup.n numbers, where n is a predetermined natural number, representing binary data modulating a predetermined physical quantity, characterized in that, successively:an "encoding" phase consists of adding to the initial sequence two "coherence" numbers to form a "total transmitted" sequence whose binary data are the subject of the said modulation, the two coherence numbers being determined so that two predetermined "coherence check" combinations applied to a total transmitted sequence each give a predetermined modulo P value, where P is a number more than 2.sup.n,a "decoding" phase consists of applying the said combinations to the numbers of the total received sequence and, where the results of the said combinations are not equal to the said predetermined modulo P values, deducing therefrom that a transmission error has occurred.

Abstract: Printing method and device enabling a low energy level to be indicated while extending the consumption duration and number of pages printed for a predetermined quantity of energy. According to the invention, detection of a predetermined quantity of energy remaining in an energy source (37) is interpreted by the control means (28) to switch to a printing mode which saves energy so as to indicate to the user an impending lack of energy, while using that which remains sparingly.