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US 4,044,880 AGranted
High speed wheel printer and method of operation
AssigneeInternational Business Machines Corporation
InventorBlair Robertson Martin
Life of this patent
Estimating the term…
Abstract
A print wheel is rotatably mounted on a carrier driven by a stepper motor to traverse the print line of a document. The wheel contains two or more arrays of characters with preferred characters most commonly used in each array and a number of lesser-used characters divided between the arrays. The print wheel normally makes one revolution for each two or more print positions and if a compare is made in each array the stepper motor advances the carrier at constant speed. Should a compare not be found or the character desired be too close to a previous character for the print hammer to settle out, the stepper motor is stopped for that position until a compare is made in some following array.
Claims18
In a printer,
- a carrier movable past a plurality of print positions along a print line of a document,
- a print element mounted on said carrier and having type bearing elements movable to print in different ones of said print positions on said document, said print element having two or more arrays of type characters, each array containing all of a group of commonly used characters and a different part of a group of less frequently used characters, said groups together comprising the entire set of printable characters to be used,
- means driving said print element, to present different ones of said type characters at said print position,
- driving means normally operable to drive said carrier at such a rate that only one of said arrays of characters is presented to a particular print position and other arrays are presented to successive adjacent print positions,
- a print hammer operable to effect impact of a selected type character with said document and having operating means for actuating said print hammer to impact selected ones of said type characters against said document to print thereon, and
- means including an emitter responsive to the positions of said type characters in said arrays on said print element and look ahead means operable to determine in advance the position in said arrays of a character which is to be printed in a particular print position operable to alter said normal operation and inhibit operation of said carrier driving means so as to stop said carrier when said character to be printed is not in the next array to be presented to said print position.
3 more elements
A serial printer apparatus comprising in combination
- a print mechanism operable for printing a line of characters or the like at plural uniformly-spaced print positions along a print line on a record medium,
- said print mechanism including a movable print element carrying a plurality of type characters in a predetermined fixed arrangement,
- said print mechanism having variable set-up times for presenting individual type characters on said print element depending on the relative location of said type characters on said print element during printing,
- means for effecting a relative motion of said print mechanism and said record medium whereby said print mechanism is positioned successively at each of said plural print positions along said print line,
- means for operating said print mechanism to effect recording of a succession of characters at said plural print positions during said relative motion,
- means operable for maintaining said relative motion at a constant first velocity when said set-up times for successive type characters to be printed at successive adjacent print positions occur within the traverse time of said print mechanism while moving at said first velocity across the space between adjacent print positions,
- traverse time determining means for determining when said set-up time for printing a character will exceed the traverse time between adjacent print positions at said first velocity, and
- velocity altering means responsive to said traverse time determining means for altering said relative motion between adjacent print positions to a second velocity including restoring said relative motion to said first velocity for printing at said adjacent print position.
5 more elements
The method of operating a printer, said printer having
- a print mechanism including a movable print element carrying a plurality of type characters or the like in a predetermined fixed arrangement, and
- drive means for effecting a relative movement of said print mechanism and a record medium for printing a line of characters at plural uniformly-spaced print positions along a print line on said record medium,
- said method comprising operating said drive means
- to effect relative motion of said print mechanism and said record medium at a constant first velocity when the set-up times for successive characters are no greater than the traverse time of said print mechanism across adjacent print positions and at a modified second velocity when the set-up times for said print mechanism exceed said traverse time,
- and restoring said relative motion during motion between adjacent print positions to said first velocity for printing during said relative motion at said first velocity.
2 more elements
Dependencies are inferred from the claim text.