Hitachi Koki Co., Ltd.

Kazunari Kodama

Toshio Hiki

Masao Miyasaka

Takashi Nakamura

Shinichi Watahiki

Youichi Hujita

Kohichi Yageta

A dot line printer has a plurality of print hammers accommodated in a hammer bank, which make dot impressions on a sheet of print paper as the hammer bank reciprocally moves in a print line direction perpendicular to the direction in which the sheet of print paper is fed. To print L dot lines at a time with each of forward and backward movements of the hammer bank, the print hammers are divided into a preselected number of groups so that each group includes N number of print hammers where L and N are integers equal to or greater than 3. The print hammers in each group are displaced one dot line distance from one another in the sheet feeding direction. The print hammers in each group are further displaced in the print line direction by respective predetermined distances from their home positions so that the respective hammers in each group do not impinge upon the sheet of print paper simultaneously. The print hammers equal in number to the least common multiple of L and N or integer multiples of the least common multiple thereof are integrally formed into a module structure to facilitate the manufacture and management of the hammer assemblies.

Print hammer arrangement in dot line printer minimizing number of

A shuttle printer carries out printing on a printing paper when a hammer bank shuttles back and fourth. At the beginning of the hammer bank reversal at the right or left end in the hammer bank shuttling path, a braking force is exerted to a shuttle motor which drives the hammer bank and an acceleration force is exerted to the shuttle motor immediately after the hammer bank turns around. In order to set a reversing duration of the hammer bank at constant, the braking force and the acceleration force exerting durations are prolonged from a predetermined minimum to a value when the hammer bank reversing duration is shortened to an extent as desired, whereby a printing paper can be fed a predetermined amount within the hammer bank reversing duration as desired.

Apparatus for controlling reversing duration of hammer bank in shuttle

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Katsuta, Japan

Kazunari Kodama