Drum column printer
AssigneeDataproducts Corporation
InventorCharles S. Mogtader
Life of this patent
Estimating the term…
Abstract
An impact printer including a type bearing drum mounted for rotation about the axis of the drum and including a plurality of hammers mounted with the impact faces thereof opposed to the drum and aligned in a direction extending parallel to the drum axis. Raised characters formed on the drum surface are oriented so that a line extending from top to bottom of the character is parallel to the drum axis. As a consequence, as the drum rotates through one revolution, the hammers can be selectively impacted against the drum to print a complete column of text on a paper web therebetween. Since the characters move past the hammers along a horizontal line of text, excellent vertical registration of the characters in a line is assured.
Claims2
An apparatus for printing a page of text by printing successive vertical columns, each column containing one character in each horizontal line of text, said apparatus comprising:
- a plurality of hammers having impact faces disposed in alignment along a print row;
- a cylindrical drum mounted adjacent to said hammers with the axis of said drum extending parallel to said print row;
- a plurality of raised characters formed on the surface of said drum disposed in columns extending parallel to said drum axis and rings extending around said drum axis, said characters being shaped to define letters of the alphabet and being oriented such that the shortest possible line between the top and bottom of each character extends substantially parallel to said drum axis;
- means for continually rotating said drum about said drum axis to sequentially bring successive columns of characters on said drum surface into alignment with said print row;
- means for alternately moving and stopping a paper web to be printed upon along a path between said drum and said hammers;
- a first memory means for storing a plurality of codes equal in number to said plurality of hammers, each code identifying a character to be printed in a particular line of a single column of text;
- a second memory means for storing multiple sets of codes, each set identifying the characters to be printed in a particular column of text;
- means for transferring each of said code sets, one set at a time, from said second memory means to said first memory means, in substantial time coincidence with said moving of said paper web;
- character counter means defining a code identifying the next character column moving into alignment with said print row;
- means for generating a timing pulse in synchronism with each successive character column moving into alignment with said print row;
- means responsive to each timing pulse for changing the code defined by said character counter means;
- means operable between successive timing pulses for sequentially comparing all of said codes stored by said first memory means with the code identified by said character counter means to detect matches therebetween;
- a hammer command register including a plurality of binary stages, each operably connected to a different one of said plurality of hammers, each stage capable of selectively defining a set or reset state;
- means responsive to each match detected by said comparing means for forcing a stage of said hammer command register to said set state;
- and
- means responsive to all hammer command register stages defining a set state for simultaneously impacting the hammers connected thereto against said drum.
Dependencies are inferred from the claim text.