| 摘要 |
<p>A dot-matrix print head (1) wherein a casing (2) houses a number of sliding print needles (3) arranged radially about a central axis (7), respective rocking members (4) associated with the needles (3), and respective electromagnets (5) for controlling the rocking members and for attracting the respective rocking members in opposition to elastic contrasting means (6) to move the respective rocking members selectively into a rest position and a print position; the elastic contrasting means (6) are defined by a substantially U-shaped monolithic annular element (6) made of elastomeric material and having two continuous circumferential projections (21, 22) spaced radially to rest, with respective predetermined loads, on respective first and second contact portions of the rocking members (4); and the annular element (6) is so shaped and sized that the ratio between the respective predetermined loads exerted by the projections (21, 22) on the respective first and second contact portions (23, 24) of the rocking members (4) ranges between roughly 7:1 and roughly 3:1 when the rocking members are in the rest position, and between roughly 3:1 and roughly 1:1 when the rocking members are in the print position. <IMAGE></p> |
