Ink jet printer dot placement compensation method

Claim 1

A method of operating a printer mechanism having a print head for printing pixels on a record medium during a plurality of line scans as said print head is moved along an axis relative to said record medium, and a stepper motor for moving said record medium in a direction orthogonal to said axis, said print head having print elements 1,2, . . . P,(P+1) . . . (P+X) responsive to selectively applied address signals 1, 2, . . . P for selectively printing pixels at adjacent pixel positions aligned in the direction of record medium movement with a distance R 1 between centers of adjacent pixel positions, and said stepper motor being responsive to energizing pulses for moving said record medium by a minimum distance R 2 where R 2 is greater than R 1 , said method comprising the steps of: during a given one of said line scans, applying the address signals 1, 2, . . . P to said print elements (n), (n+1), . . . (n+P-1) whereby no more than P of said print elements print pixels during said given one of said line scans, n being a positive integer from 1 to X; after said given one of said line scans, applying pulses to the stepper motor to move the record medium a distance k 2 R 2 ; and, during another of the line scans following said movement of the record medium by said distance k 2 R 2 , applying the address signals 1, 2, . . . P to said print elements (1+k 1 ),(2+k 1 ) . . . (P+k 1 ) whereby pixels are printed with a shift of k 1 R 1 in a direction parallel to the direction the record medium is moved, where k 2 , P and X are positive integers and k 1 is an integer no less than 0 and k 1 R 1 +k 2 R 2 =PR 1 .

Claim 2

A method of operating a printer mechanism having a print head for printing pixels on a record medium during a plurality of line scans as said print head is moved along an axis relative to said record medium, and a stepper motor for moving said record medium in a direction orthogonal to said axis, said print head having print elements 1,2, . . . P,(P+1) . . . (P+X) responsive to selectively applied address signals 1, 2, . . . P for selectively printing pixels at adjacent pixel positions aligned in the direction of record medium movement with a distance R 1 between centers of adjacent pixel positions, and said stepper motor being responsive to energizing pulses for moving said record medium by a minimum distance R 2 where R 2 is greater than R 1 , said method comprising the steps of: during a given one of said line scans, applying the address signals 1, 2, . . . P to said print elements (n), (n+1), . . . (n+P-1) whereby no more than P of said print elements print pixels during said given one of said line scans, n being a positive integer from 1 to X; after said given one of said line scans, applying pulses to the stepper motor to move the record medium a distance k 2 R 2 ; and, during another of the line scans following said movement of the record medium by said distance k 2 R 2 , applying the address signals 1, 2, . . . P to said print elements (1+k 1 ),(2+k 1 ) . . . (P+k 1 ) whereby pixels are printed with a shift of k 1 R 1 in a direction parallel to the direction the record medium is moved, where k 2 , P and X are positive integers and k 1 is an integer no less than 0 and k 1 R 1 +k 2 R 2 =PR 1 .

Claim 3

A method of operating a printer mechanism to obtain all points addressable printing of pixels over plural line scans with the center-to center distance between all pixel print positions in the director of record movement being exactly R 1 , said printer mechanism having a print head for printing pixels on a record medium during a plurality of line scans as said print head is moved along an axis relative to said record medium, and a stepper motor for moving said record medium in a direction orthogonal to said axis, said print head having print elements 1,2, . . . P,(P+1) . . . (P+X) responsive to selectively applied address signals 1, 2, . . . P for selectively printing pixels at adjacent pixel positions aligned in the direction of record medium movement with a distance R 1 between centers of adjacent pixel positions, and said stepper motor being responsive to energizing pulses for moving said record medium by a minimum distance R 2 where R 2 is greater than R 1 , said method comprising the following steps: step 1) during each of said line scans, applying the address signals 1, 2, . . . P to said print elements (1+k 1 ),(2+k 1 ), . . . (P+k 1 ) whereby pixels are printed with a shift distance of k 1 R 1 relative to where pixels would have been printed if said signals had been applied to said print elements 1, 2, . . . P, respectively, the shift distance being in a direction parallel to the direction the record medium is moved, k 1 being an integer from 0 to X; step 2) between successive ones of said line scans, applying a number of pulses to the stepper motor to move the record medium a distance k 2 R 2 , and, step 3) repeatedly carrying out step 1 and step 2 while applying said address signals to different ones of said print elements to vary said shift distance k 1 R 1 , and while varying the number of pulses applied to said stepper motor so that a sum of the distance k 2 R 2 that the record medium is moved when a given step 2 is carried out and the shift distance k 1 R 1 that the pixels are printed during a step 1 next succeeding said given step 2 is equal to PR 1 , k 2 , P and X being positive integers.

Claim 4

A method of operating a printer mechanism to obtain all points addressable printing of pixels over plural line scans with the center-to center distance between all pixel print positions in the director of record movement being exactly R 1 , said printer mechanism having a print head for printing pixels on a record medium during a plurality of line scans as said print head is moved along an axis relative to said record medium, and a stepper motor for moving said record medium in a direction orthogonal to said axis, said print head having print elements 1,2, . . . P,(P+1) . . . (P+X) responsive to selectively applied address signals 1, 2, . . . P for selectively printing pixels at adjacent pixel positions aligned in the direction of record medium movement with a distance R 1 between centers of adjacent pixel positions, and said stepper motor being responsive to energizing pulses for moving said record medium by a minimum distance R 2 where R 2 is greater than R 1 , said method comprising the following steps: step 1) during each of said line scans, applying the address signals 1, 2, . . . P to said print elements (1+k 1 ),(2+k 1 ), . . . (P+k 1 ) whereby pixels are printed with a shift distance of k 1 R 1 relative to where pixels would have been printed if said signals had been applied to said print elements 1, 2, . . . P, respectively, the shift distance being in a direction parallel to the direction the record medium is moved, k 1 being an integer from 0 to X; step 2) between successive ones of said line scans, applying a number of pulses to the stepper motor to move the record medium a distance k 2 R 2 , and, step 3) repeatedly carrying out step 1 and step 2 while applying said address signals to different ones of said print elements to vary said shift distance k 1 R 1 , and while varying the number of pulses applied to said stepper motor so that a sum of the distance k 2 R 2 that the record medium is moved when a given step 2 is carried out and the shift distance k 1 R 1 that the pixels are printed during a step 1 next succeeding said given step 2 is equal to PR 1 , k 2 , P and X being positive integers.

Claim 11

A method of operating a printer mechanism having a print head for printing pixels on a record medium during a plurality of line scans as said print head is moved along an axis relative to said record medium, and a stepper motor for moving said record medium in a direction orthogonal to said axis, said print head having a plurality of print elements 1,2 . . . P,(P+1) . . . (P+X) responsive to selectively applied address signals 1, 2, . . . P for selectively printing pixels at adjacent pixel positions aligned in the direction of record medium movement with a distance R 1 between centers of adjacent pixel positions, and said stepper motor being responsive to energizing pulses for moving said record medium by a minimum distance R 2 where R 2 is greater than R 1 , said method comprising the following steps: step 1) during a given one of said line scans, applying the address signals 1, 2, . . . P to said print elements (1+k 1 ), (2+k 1 ) . . . (P+k 1 ) whereby said print elements print pixels which are shifted by a shift distance k 1 R 1 relative to where pixels would have been printed if said addressing signals had been applied to said print elements 1,2, . . . P, respectively, the shift distance being parallel to the direction the record medium is moved and k 1 being zero or a positive integer no greater than X; step 2) between successive ones of said line scans, applying pulses to the stepper motor to move the record medium a distance k 2 R 2 ; and, step 3) repeatedly executing step 1 and step 2 while applying said address signals to different ones of said print elements to vary said shift distance k 1 R 1 and while varying the number of pulses applied to said stepper motor so that a sum of the distance k 2 R 2 that the record medium is moved when step 2 is executed and the shift distance k 1 R 1 that the pixels are printed during a next succeeding execution of step 1 differs from PR 1 by no more than one-half R 1 , k 2 , P and X being positive integers.

Claim 12

A method of operating a printer mechanism having a print head for printing pixels on a record medium during a plurality of line scans as said print head is moved along an axis relative to said record medium, and a stepper motor for moving said record medium in a direction orthogonal to said axis, said print head having a plurality of print elements 1,2 . . . P,(P+1) . . . (P+X) responsive to selectively applied address signals 1, 2, . . . P for selectively printing pixels at adjacent pixel positions aligned in the direction of record medium movement with a distance R 1 between centers of adjacent pixel positions, and said stepper motor being responsive to energizing pulses for moving said record medium by a minimum distance R 2 where R 2 is greater than R 1 , said method comprising the following steps: step 1) during a given one of said line scans, applying the address signals 1, 2, . . . P to said print elements (1+k 1 ), (2+k 1 ) . . . (P+k 1 ) whereby said print elements print pixels which are shifted by a shift distance k 1 R 1 relative to where pixels would have been printed if said addressing signals had been applied to said print elements 1,2, . . . P, respectively, the shift distance being parallel to the direction the record medium is moved and k 1 being zero or a positive integer no greater than X; step 2) between successive ones of said line scans, applying pulses to the stepper motor to move the record medium a distance k 2 R 2 ; and, step 3) repeatedly executing step 1 and step 2 while applying said address signals to different ones of said print elements to vary said shift distance k 1 R 1 and while varying the number of pulses applied to said stepper motor so that a sum of the distance k 2 R 2 that the record medium is moved when step 2 is executed and the shift distance k 1 R 1 that the pixels are printed during a next succeeding execution of step 1 differs from PR 1 by no more than one-half R 1 , k 2 , P and X being positive integers.