Position sensing for matrix printer
AssigneeNCR Corporation
InventorChih H. Liu
Life of this patent
Estimating the term…
Abstract
An alternating current coupled dot column sensing circuit provides delayed dot position signals for control logic of a matrix printer to actuate the printing elements at the proper dot column positions in bi-directional printing. A sensor recognizes edges of slots in a timing strip across the printer and also recognizes end or home positions of the strip for use in such printing.
Claims13
Apparatus for positioning single wire printing elements in precise position in bi-directional matrix printing, comprising a
- carriage carrying said printing elements for bi-directional movement,
- cam means operably connected with said carriage for moving said printing elements in one and the other direction, a
- plurality of solenoids on said carriage and having a response time for operating said printing elements for printing in dot row manner, a
- timing member caused to be moved with said printing elements in said one and the other direction, said timing member having indicia indicating column positions of dot portions of a character, and spaced areas comprising a light area at one end of said timing member and a dark area at the other end thereof indicating end positions of travel of said printing elements, a
- sensing member positioned in relation to and operable with said movable timing member to sense and respond to said spaced light and dark areas thereof to indicate the one and the other direction of movement of said printing elements and to respond to said indicia thereof for causing said printing elements to be operated for printing, and
- means for delaying the time of moving said printing elements in said one and the other direction in relation to the response time of said solenoids for operating said printing elements at said column positions in dot row printing manner.
In a printer having a carriage reciprocable thereacross, a plurality of solenoids supported from said carriage for driving printing elements in dot matrix printing of characters, means for positioning the dots in precise columns during bi-directional printing, comprising a
- timing member secured to said carriage and movable therewith, a
- sensor on said printer and operably associated with said timing member, said timing member having indicia indicating dot column positions with carriage home positions comprising a light area at one end of said timing member and a dark area at the other end thereof, said sensor generating pulses from sensing said indicia corresponding to the dot columns of characters to be printed, and sensing the light and dark area home positions of said timing member indicating the direction of movement of said carriage, and
- means for delaying the time of movement of said carriage upon detecting said indicia in relation to the response time of said solenoids after actuation thereof.
Apparatus for controlling the firing of print wire solenoids in a dot matrix printer comprising a
- print head carriage,
- cam means for moving said carriage reciprocably across said printer for printing in bi-directional manner, a
- timing member carried by said carriage, said timing member having a plurality of apertures therein and spaced in a manner coinciding with dot column positions across said printer and including indicia of light area at one end of said timing member and of dark area at the other end thereof representing non-printing margins for indicating end positions of travel of said carriage, a
- sensor for sensing said apertures to provide a pulse for each dot in a column to be printed and for sensing the light and dark area indicia to indicate direction of travel of said carriage and initiate reversal thereof to provide spacing between lines of dots and of characters, and
- means for delaying the firing of said solenoids pursuant to the dot column positions in relation to the response time of solenoid firing.
Dependencies are inferred from the claim text.