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Print Hammer Impact Control Mechanism

IP.com Disclosure Number: IPCOM000096341D
Original Publication Date: 1963-Apr-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 3 page(s) / 56K

Publishing Venue

IBM

Related People

Bear, ME: AUTHOR [+2]

Abstract

In this printing mechanism, print quality is significantly improved by varying the firing position of print hammers in accordance with the area of the type character to be printed. Hammer impact energy is controlled to more uniformly deposit ink on a document. Thus, either embossing characters of small area or leaving ink voids in characters of large area is avoided.

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Print Hammer Impact Control Mechanism

In this printing mechanism, print quality is significantly improved by varying the firing position of print hammers in accordance with the area of the type character to be printed. Hammer impact energy is controlled to more uniformly deposit ink on a document. Thus, either embossing characters of small area or leaving ink voids in characters of large area is avoided.

The type characters, such as 0 ... 9, are divided into two groups according to area. A characteristic hammer firing position is provided for each group. However, more groups, each with a hammer firing position, can be created.

Only one of a plurality of printing orders is shown in the printing mechanism. This is adapted for use with a keyboard unit, not shown. The depression of a key displaces one of a plurality of stop pins, each serving as a unique stop for longitudinally movable setup member 1. 1 is permitted to move to the right a distance corresponding to the keyboard character selected. After member 1 is positioned cam-operated bail 2 extending through slot 3 of typewheel gear 4 is moved clockwise. Such permits gear 4 to rotate under the force of spring 5 through drive rack 6 and rotate typewheel 7. Typewheel 7 rotates until depending portion 8 of rack 6 strikes projection 9 on member 1. This movement brings the selected type character to printing position 10 adjacent ribbon 11 and document 12. Aligner bail 13 subsequently enters teeth 14 to hold typewheel 7 during printing.

Gear 4 is formed with low and high dwells 15 and 16 respectively about a portion of its periphery. These are sensed by pivotally mounted hammer latch setup arm 17 after typewheel 7 is positioned. A high or low dwell corresponds with the area of the type character in printing position. If a character is of large area a low dwell is sensed, and vice versa. The resulting movement of arm 17 is transmitted through link 18 to permit hammer latch 19 to rotate about pivot 20 and render latching positions 21 or 22 effective to hold print hammer 23 in firing position.

During the setup of typewheel 7 print hammer 23 is held against spring 25 in approximately the position shown by hammer bail 26 operated by a cam, not shown, on cam shaft 27. Also during this time, cam-operated control bail 29 maintains interposer 30 downwardly against tail 19a of hammer latch 19 The result is that hammer tail 28 rests below latch...