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Browse Prior Art Database

Homing Mechanism for Wheel Printers

IP.com Disclosure Number: IPCOM000046245D
Original Publication Date: 1983-Jun-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 3 page(s) / 52K

Publishing Venue

IBM

Related People

Blanck, TW: AUTHOR [+2]

Abstract

In daisy-wheel-type printers, it is essential that the machine always know where the position of the print wheel is in order that selected characters may be brought to the print position in line with the print hammer. In open-loop systems, counters or other electronic means may be employed to maintain track of the position of the print wheel. This is possible as long as the initial or starting position of the print wheel is known. Disclosed is a simple apparatus which permits the absolute positioning of the print wheel at selected times, such as power on reset (POR).

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Homing Mechanism for Wheel Printers

In daisy-wheel-type printers, it is essential that the machine always know where the position of the print wheel is in order that selected characters may be brought to the print position in line with the print hammer. In open-loop systems, counters or other electronic means may be employed to maintain track of the position of the print wheel. This is possible as long as the initial or starting position of the print wheel is known. Disclosed is a simple apparatus which permits the absolute positioning of the print wheel at selected times, such as power on reset (POR).

Referring now to the drawings, a print wheel 10 is connected to a hub 11 with a barrel 12 thereon which is adapted to connect to the motor shaft of a selection motor (not shown). As illustrated, the hub 12 includes a radially projecting offset portion 13, the purpose for which will become more evident hereinafter.

In order to home the print wheel, homing latch mechanism 20 is mounted on a portion of the movable carrier 15, such as the existing motor plate, for engagement with the print wheel hub offset or projection 13 to permit homing of the print wheel 10 (at selected times) into a predetermined position. To this end, the homing latch mechanism 20 comprises a latch spring 23 having an offset portion 24 which is spaced from the carrier 15, and which merges through an angled or beveled portion 25 into a mounting tab portion 26 which is coupled, as by screws 27, to the carrier 15. The latch spring 23 is split so as to form an elongated tongue 28 which normally is disposed in a plane parallel to the plane of the carrier 15 but axially spaced from the terminal end 12a of the hub 12 (as illustrated in solid lines).

Mounted in a slot in the carrier 15 is a slide 30, the terminal end (not shown) of the slide 30 being disposed in the sloped or beveled portion 25 to engage the base of the tongue 28. The opposite termina...