Importance

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Abstract

Apparatus for automatically adjusting the distance of a printing head from a printing support wherein motor means enable changing, on command, the print head distance from the support and a movable armature/plunger electromagnetic detector, fixed to the printing head is energized, when the print head is moved far from the printing support, so as to perform the cocking of the armature/plunger and is thereafter maintained in energized status by a minimal current for holding the electromagnet in cocked state, so that a subsequent movement of the print head towards the printing support, owing to the interference with the printing support of an actuation element coupled to the armature/plunger, causes armature/plunger release and a reluctance change, hence an e.m.f. induced in the energization winding which is detected by a comparator circuit and signaled to a control logic to indicate that the print head is at a predetermined distance from the printing support. If the print head is provided with electromagnetic printing actuators, the detection function may be performed by one or more actuation elements.

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First Claim