US4425844A — Home pulse compensation for multiple speed line p…

Claim 1

Independent Claim 333 words

In a printer system wherein a printer mechanism comprises a plurality of type characters movable in a closed path and a plurality of print hammers electrically operable for engaging said type characters at print positions along said path to effect printing of said type characters on a print medium, drive means for producing constant motion of said type characters at a plurality of speeds relative to said print hammers whereby printing occurs at a corresponding plurality of printing rates, means for selectively operating said print hammers in timed relation with the motion of said type characters to effect on-the-fly printing at said plurality of print rates including print control means operable for providing character identifying signals including a reference character signal in synchronism with the motion of said characters at said plurality of speeds, means for synchronizing the operation of said print controls with said type characters during said motion at said plurality of speeds including, means for generating reference pulses indicative of the motion of a reference type characters relative to a reference position on said closed path located at a predetermined lead distance from a given print hammer, said lead distance being a fixed distance dependent on the flight time of said given print hammer to effect engagement with said reference character when moving at one of said speeds, sync control means connected to said print control means for receiving said character identifying signals, said sync control being operative for determining the coincidence of said reference character signal from said print control and said reference pulses, and compensating circuit means connected between said reference pulse generating means and said sync control means, said compensating circuit means having adjustment means operable for electrically modifying the timing of said reference pulses for application to said sync control means, said adjustment means being operable for modifying the timing of said reference pulses in accordance with changes in said speed of said type characters by said drive means from said one of said constant speeds.

Claim 2

Dependent Claim 333 words

In a printer system wherein a printer mechanism comprises a plurality of type characters movable in a closed path and a plurality of print hammers electrically operable for engaging said type characters at print positions along said path to effect printing of said type characters on a print medium, drive means for producing constant motion of said type characters at a plurality of speeds relative to said print hammers whereby printing occurs at a corresponding plurality of printing rates, means for selectively operating said print hammers in timed relation with the motion of said type characters to effect on-the-fly printing at said plurality of print rates including print control means operable for providing character identifying signals including a reference character signal in synchronism with the motion of said characters at said plurality of speeds, means for synchronizing the operation of said print controls with said type characters during said motion at said plurality of speeds including, means for generating reference pulses indicative of the motion of a reference type characters relative to a reference position on said closed path located at a predetermined lead distance from a given print hammer, said lead distance being a fixed distance dependent on the flight time of said given print hammer to effect engagement with said reference character when moving at one of said speeds, sync control means connected to said print control means for receiving said character identifying signals, said sync control being operative for determining the coincidence of said reference character signal from said print control and said reference pulses, and compensating circuit means connected between said reference pulse generating means and said sync control means, said compensating circuit means having adjustment means operable for electrically modifying the timing of said reference pulses for application to said sync control means, said adjustment means being operable for modifying the timing of said reference pulses in accordance with changes in said speed of said type characters by said drive means from said one of said constant speeds.

Claim 3

Dependent Claim 73 words

In a printer system in accordance with claim 1 in which said plurality of constant speeds includes a high speed and at least one lower speed, said one constant speed being said high speed, and said compensating circuit means comprises delay circuit means connected to receive said reference pulses from said reference pulse generating means, said delay circuit means being adjustable for modifying the timing of said reference pulses for said lower speed.

Claim 4

Dependent Claim 27 words

In a printer system in accordance with claim 2 in which said delay circuit means is a programmable means for modifying the timing of said reference pulses.

Claim 5

Dependent Claim 75 words

In a printer system in accordance with claim 3 in which said means for synchronizing the operation of said print control means includes timing means associated with said moving type characters for generating timing pulses in sychronism with the motion of said type characters, and said delay circuit means is operable for modifying the timing of said reference pulses in response to a predetermined number of said timing pulses associated with said plurality of speeds.

Claim 6

Dependent Claim 117 words

In a printer system in accordance with claim 4 in which said type characters and said plurality of print hammers have a pitch differential whereby said characters and said print hammers are alignable in scan and subscan sequences, said timing means associated with said moving type characters include means for generating scan and subscan timing signals in synchronism with the motion of said type characters, and said delay circuit means is operable for modifying the timing of said reference pulses for counting a predetermined number of said subscan pulses in response to said reference pulses, said predetermined number or said subscan pulses being variable in proportion to changes of said type character speed from said constant speed.

Claim 7

Dependent Claim 102 words

In a printer system in accordance with claim 5 in which said delay circuit means comprises counter means operable in response to said reference pulses from said reference pulse generating means for counting said timing pulses, storage means for storing a count value representing the number of timing pulses required for delaying the reference pulses at said plurality of speeds, and comparison means connected to said counter means and to said storage means for supplying a true home pulse signal to said sync control means when said count registered in said count means corresponds to said count value in said storage means.

Claim 8

Dependent Claim 44 words

In a printer system in accordance with claim 6 in which said storage means comprises a register means which is electrically alterable for storing a first count value for said higher speed and a second count value for said at least one lower speed.

Claim 9

Dependent Claim 138 words

In a printer system in accordance with claim 7 in which said print mechanism comprises an endless flexible type band, said type characters are uniformly spaced in a single row on said flexible type band, said drive means includes spaced pulleys for revolving said type band whereby said type characters move in said closed path at said plurality of speeds, said timing means comprises a row of timing marks fixed on said band, said timing signals being in alignment with and spaced equally with said plurality of type characters, and said first means for generating scan signals comprises stationary transducer means for sensing said timing marks during revolution of said type band by said drive means at said plurality of speeds, and said drive means includes motor means operable for driving said pulleys at said plurality of speeds.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1987-01-16	1987-07-18	1988-01-17	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1991-01-16	1991-07-18	1992-01-17	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1995-01-16	1995-07-18	1996-01-17	$7700.00	Window Closed / Lapsed

Home pulse compensation for multiple speed line printer

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