Ink jet recorder

Abstract

On a sheet of paper on which an image has already been formed, a first registration mark pair and a second registration mark pair are printed. The first registration mark pair and second registration mark pair each consist of a pair of registration marks that are arranged to be spaced apart in a paper-width direction, the second registration mark pair located posterior to the first registration mark pair in the paper-conveying direction. Based on the actual positional relationship between the first registration mark pair and the second registration mark pair that are read by a reading unit, a correction unit corrects discharge data that corresponds to an image formation area located between the first registration mark pair and the second registration mark pair.

What is claimed is: 
     
       1. An ink jet recorder configured to perform an overcoating process, wherein an overcoating ink is discharged onto a sheet of paper on which a registration mark that serves as a reference for identifying an image formation position is printed and on which an image has already been formed, such that the overcoating ink is superimposed on the image, the ink jet recorder comprising:
 a conveying mechanism that conveys the sheet of paper on which the image has already been formed;   a recording head that functions to discharge the overcoating ink onto a printing surface of the sheet of paper, on which the image has already been formed;   a reader that is arranged upstream, in a paper-conveying direction, of the recording head and that reads the registration mark printed on the sheet of paper that is conveyed;   a memory unit that stores data that is set in advance, based on a design correspondence relationship between a printing position of the registration mark and the image formation position in the sheet of paper, wherein the data is discharge data for identifying a discharge pattern of the overcoating ink discharged from the recording head;   a controller that performs the discharge control of the recording head based on the discharge data; and   a correction unit that corrects the discharge data based on information read for the registration mark,   wherein, on the sheet of paper on which the image has already been formed, a first registration mark pair and a second registration mark pair are printed, the first registration mark pair and second registration mark pair each consisting of a pair of registration marks that are arranged to be spaced apart in a paper-width direction perpendicular to the paper-conveying direction, the second registration mark pair located posterior to the first registration mark pair in the paper-conveying direction, and   wherein, based on the actual positional relationship between the first registration mark pair and the second registration mark pair that are read by the reading unit, the correction unit corrects discharge data that corresponds to an image formation area located between the first registration mark pair and the second registration mark pair.   
     
     
       2. The ink jet recorder according to  claim 1 , wherein, on the sheet of paper on which the image has already been formed, a third registration mark pair is further printed located posterior to the second registration mark pair in the paper-conveying direction and consisting of a pair of registration marks that are arranged to be spaced apart in the paper-width direction, and
 wherein the correction unit sequentially performs a first correction, which is a correction on the discharge data that corresponds to a first image formation area located between the first registration mark pair and the second registration mark pair, and a second correction, which is a correction on the discharge data that corresponds to a second image formation area located between the second registration mark pair and the third registration mark pair.   
     
     
       3. The ink jet recorder according to  claim 2 , An ink jet recorder configured to perform an overcoating process, wherein an overcoating ink is discharged onto a sheet of paper on which a registration mark that serves as a reference for identifying an image formation position is printed and on which an image has already been formed, such that the overcoating ink is superimposed on the image, the ink jet recorder comprising:
 a conveying mechanism that conveys the sheet of paper on which the image has already been formed; 
 a recording head that functions to discharge the overcoating ink onto a printing surface of the sheet of paper, on which the image has already been formed; 
 a reader that is arranged upstream, in a paper-conveying direction, of the recording head and that reads the registration mark printed on the sheet of paper that is conveyed; 
 a memory unit that stores data that is set in advance, based on a design correspondence relationship between a printing position of the registration mark and the image formation position in the sheet of paper, wherein the data is discharge data for identifying a discharge pattern of the overcoating ink discharged from the recording head; 
 a controller that performs the discharge control of the recording head based on the discharge data; and 
 a correction unit that corrects the discharge data based on information read for the registration mark, 
 wherein, on the sheet of paper on which the image has already been formed, a first registration mark pair and a second registration mark pair are printed, the first registration mark pair and second registration mark pair each consisting of a pair of registration marks that are arranged to be spaced apart in a paper-width direction perpendicular to the paper-conveying direction, the second registration mark pair located posterior to the first registration mark pair in the paper-conveying direction, 
 wherein, based on the actual positional relationship between the first registration mark pair and the second registration mark pair that are read by the reading unit, the correction unit corrects discharge data that corresponds to an image formation area located between the first registration mark pair and the second registration mark pair, 
 wherein, on the sheet of paper on which the image has already been formed, a third registration mark pair is further printed located posterior to the second registration mark pair in the paper-conveying direction and consisting of a pair of registration marks that are arranged to be spaced apart in the paper-width direction, 
 wherein the correction unit sequentially performs a first correction, which is a correction on the discharge data that corresponds to a first image formation area located between the first registration mark pair and the second registration mark pair, and a second correction, which is a correction on the discharge data that corresponds to a second image formation area located between the second registration mark pair and the third registration mark pair, and 
 wherein the correction unit performs the second correction in parallel with the discharge control, based on discharge data obtained by the first correction. 
 
     
     
       4. The ink jet recorder according to  claim 1 , An ink jet recorder configured to perform an overcoating process, wherein an overcoating ink is discharged onto a sheet of paper on which a registration mark that serves as a reference for identifying an image formation position is printed and on which an image has already been formed, such that the overcoating ink is superimposed on the image, the ink jet recorder comprising:
 a conveying mechanism that conveys the sheet of paper on which the image has already been formed; 
 a recording head that functions to discharge the overcoating ink onto a printing surface of the sheet of paper, on which the image has already been formed; 
 a reader that is arranged upstream, in a paper-conveying direction, of the recording head and that reads the registration mark printed on the sheet of paper that is conveyed; 
 a memory unit that stores data that is set in advance, based on a design correspondence relationship between a printing position of the registration mark and the image formation position in the sheet of paper, wherein the data is discharge data for identifying a discharge pattern of the overcoating ink discharged from the recording head; 
 a controller that performs the discharge control of the recording head based on the discharge data; and 
 a correction unit that corrects the discharge data based on information read for the registration mark, 
 wherein, on the sheet of paper on which the image has already been formed, a first registration mark pair and a second registration mark pair are printed, the first registration mark pair and second registration mark pair each consisting of a pair of registration marks that are arranged to be spaced apart in a paper-width direction perpendicular to the paper-conveying direction, the second registration mark pair located posterior to the first registration mark pair in the paper-conveying direction, 
 wherein, based on the actual positional relationship between the first registration mark pair and the second registration mark pair that are read by the reading unit, the correction unit corrects discharge data that corresponds to an image formation area located between the first registration mark pair and the second registration mark pair, 
 wherein the correction unit acquires, as a measured position, the position of a pair of registration marks that constitute each of the registration mark pairs based on information read by the reading unit, and 
 wherein the correction unit corrects the discharge data that corresponds to a specific image formation area surrounded by a pair of registration marks that constitute a front registration mark pair in the paper-conveying direction and a pair of registration marks that constitute a rear registration mark pair in the paper-conveying direction based on a difference between a reference position, which is a designed position of each registration mark stored in advance in the memory unit, and a measured position of each registration mark that has been actually acquired. 
 
     
     
       5. The ink jet recorder according to  claim 4 , wherein the recording head is configured to include nozzles that discharge an overcoating ink lined in the paper-width direction, and, when a specific image formation area surrounded by respective measured positions of the registration marks is deformed with respect to a specific image formation area surrounded by respective reference positions of the registration marks, the correction unit corrects the discharge data so as to increase or decrease, on average, the number of nozzles for discharging an overcoating ink in the recording head in the paper-conveying direction or the paper-width direction in accordance with the deformation of the specific image formation area. 
     
     
       6. The ink jet recorder according to claim  1  4, wherein the memory unit stores: position information of the first registration mark pair and position information of the second registration mark pair that correspond to the discharge data stored in advance; and information regarding a spacing interval between the recording head and the reading unit in the paper-conveying direction,
 wherein the correction unit performs, without performing a correction of the discharge data for at least a first sheet of paper on which an image has already been formed, a correction of the discharge data for a subsequent sheet of paper on which an image has already formed, based on the actual positional relationship between the first registration mark pair and the second registration mark pair read for the first sheet of paper on which the image has already been formed, and 
 wherein the controller performs, without performing discharge control of the recording head on the first sheet of paper on which the image has already been formed, discharge control of the recording head based on the discharge data as corrected for the subsequent sheet of paper on which the image has already been formed. 
 
     
     
       7. The ink jet recorder according to  claim 6 , wherein, when an interval between the registration marks that constitute the first registration mark pair and the registration marks that constitute the second registration mark pair is greater than or equal to the spacing interval between the recording head and the reading unit in the paper-conveying direction, the correction unit performs, without performing a correction of the discharge data for at least a first sheet of paper on which an image has already been formed, a correction of the discharge data for a subsequent sheet of paper on which an image has already formed, based on the actual positional relationship between the first registration mark pair and the second registration mark pair read for the first sheet of paper on which the image has already been formed. 
     
     
       8. The ink jet recorder according to  claim 6 , wherein, when correction is not performed for the first sheet of paper on which the image has already been formed, the controller performs, without performing discharge control of the recording head on the first sheet of paper on which the image has already been formed, discharge control of the recording head based on the discharge data as corrected for the subsequent sheet of paper on which the image has already been formed. 
     
     
       9. The ink jet recorder according to claim  1  4, wherein the overcoating ink is an ultraviolet curable UV ink. 
     
     
       10. The ink jet recorder according to  claim 9 , further comprising:
 an ultraviolet-ray irradiation unit that is arranged downstream of the recording head in the paper-conveying direction and that cures, by irradiating the sheet of paper that is conveyed with an ultraviolet ray, the UV ink on the sheet of paper. 
 
     
     
       11. An ink jet recorder configured to perform an overcoating process, wherein an overcoating ink is discharged onto a sheet of paper on which a registration mark that serves as a reference for identifying an image formation position is printed and, such that the overcoating ink is superimposed on the image, the ink jet recorder comprising:
 a conveying mechanism that conveys the sheet of paper;   a recording head that functions to discharge the overcoating ink onto a printing surface of the sheet of paper;   a reader that is arranged upstream, in a paper-conveying direction, of the recording head and that reads the registration mark printed on the sheet of paper that is conveyed;   a memory unit that stores data that is set in advance, based on a design correspondence relationship between a printing position of the registration mark and the image formation position in the sheet of paper, wherein the data is discharge data for identifying a discharge pattern of the overcoating ink discharged from the recording head;   a controller that performs the discharge control of the recording head based on the discharge data; and   a correction unit that corrects the discharge data based on information read for the registration mark,   wherein, on the sheet of paper, a first registration mark pair and a second registration mark pair are printed, the first registration mark pair and second registration mark pair each consisting of a pair of registration marks that are arranged to be spaced apart in a paper-width direction perpendicular to the paper-conveying direction, the second registration mark pair located posterior to the first registration mark pair in the paper-conveying direction,   wherein, based on the actual positional relationship between the first registration mark pair and the second registration mark pair that are read by the reading unit, the correction unit corrects discharge data that corresponds to an image formation area located between the first registration mark pair and the second registration mark pair,   wherein a third registration mark pair is further printed located posterior to the second registration mark pair in the paper-conveying direction and consisting of a pair of registration marks that are arranged to be spaced apart in the paper-width direction,   wherein the correction unit sequentially performs a first correction, which is a correction on the discharge data that corresponds to a first image formation area located between the first registration mark pair and the second registration mark pair, and a second correction, which is a correction on the discharge data that corresponds to a second image formation area located between the second registration mark pair and the third registration mark pair, and   wherein the correction unit performs the second correction in parallel with the discharge control, based on discharge data obtained by the first correction.   
     
     
       12. An ink jet recorder configured to perform an overcoating process, wherein an overcoating ink is discharged onto a sheet of paper on which a registration mark that serves as a reference for identifying an image formation position is printed and, such that the overcoating ink is superimposed on the image, the ink jet recorder comprising:
 a conveying mechanism that conveys the sheet of paper;   a recording head that functions to discharge the overcoating ink onto a printing surface of the sheet of paper;   a reader that is arranged upstream, in a paper-conveying direction, of the recording head and that reads the registration mark printed on the sheet of paper that is conveyed;   a memory unit that stores data that is set in advance, based on a design correspondence relationship between a printing position of the registration mark and the image formation position in the sheet of paper, wherein the data is discharge data for identifying a discharge pattern of the overcoating ink discharged from the recording head;   a controller that performs the discharge control of the recording head based on the discharge data; and   a correction unit that corrects the discharge data based on information read for the registration mark,   wherein, on the sheet of paper, a first registration mark pair and a second registration mark pair are printed, the first registration mark pair and second registration mark pair each consisting of a pair of registration marks that are arranged to be spaced apart in a paper-width direction perpendicular to the paper-conveying direction, the second registration mark pair located posterior to the first registration mark pair in the paper-conveying direction,   wherein, based on the actual positional relationship between the first registration mark pair and the second registration mark pair that are read by the reading unit, the correction unit corrects discharge data that corresponds to an image formation area located between the first registration mark pair and the second registration mark pair,   wherein the correction unit acquires, as a measured position, the position of a pair of registration marks that constitute each of the registration mark pairs based on information read by the reading unit, and   wherein the correction unit corrects the discharge data that corresponds to a specific image formation area surrounded by a pair of registration marks that constitute a front registration mark pair in the paper-conveying direction and a pair of registration marks that constitute a rear registration mark pair in the paper-conveying direction based on a difference between a reference position, which is a designed position of each registration mark stored in advance in the memory unit, and a measured position of each registration mark that has been actually acquired.   
     
     
       13. The ink jet recorder according to claim 12, wherein the recording head is configured to include nozzles that discharge an overcoating ink lined in the paper-width direction, and, when a specific image formation area surrounded by respective measured positions of the registration marks is deformed with respect to a specific image formation area surrounded by respective reference positions of the registration marks, the correction unit corrects the discharge data so as to increase or decrease, on average, the number of nozzles for discharging an overcoating ink in the recording head in the paper-conveying direction or the paper-width direction in accordance with the deformation of the specific image formation area. 
     
     
       14. The ink jet recorder according to claim 12, wherein the memory unit stores: position information of the first registration mark pair and position information of the second registration mark pair that correspond to the discharge data stored in advance; and information regarding a spacing interval between the recording head and the reading unit in the paper-conveying direction,
 wherein the correction unit performs, without performing a correction of the discharge data for at least a first sheet of paper, a correction of the discharge data for a subsequent sheet of paper, based on the actual positional relationship between the first registration mark pair and the second registration mark pair read for the first sheet of paper, and   wherein the controller performs, without performing discharge control of the recording head on the first sheet of paper, discharge control of the recording head based on the discharge data as corrected for the subsequent sheet of paper.   
     
     
       15. The ink jet recorder according to claim 14, wherein, when an interval between the registration marks that constitute the first registration mark pair and the registration marks that constitute the second registration mark pair is greater than or equal to the spacing interval between the recording head and the reading unit in the paper-conveying direction, the correction unit performs, without performing a correction of the discharge data for at least a first sheet of paper, a correction of the discharge data for a subsequent sheet of paper, based on the actual positional relationship between the first registration mark pair and the second registration mark pair read for the first sheet of paper. 
     
     
       16. The ink jet recorder according to claim 14, wherein, when correction is not performed for the first sheet of paper, the controller performs, without performing discharge control of the recording head on the first sheet of paper, discharge control of the recording head based on the discharge data as corrected for the subsequent sheet of paper. 
     
     
       17. The ink jet recorder according to claim 12, wherein the overcoating ink is an ultraviolet curable UV ink. 
     
     
       18. The ink jet recorder according to claim 17, further comprising:
 an ultraviolet-ray irradiation unit that is arranged downstream of the recording head in the paper-conveying direction and that cures, by irradiating the sheet of paper that is conveyed with an ultraviolet ray, the UV ink on the sheet of paper.   
     
     
       19. An ink jet recorder configured to perform an overcoating process, wherein an overcoating ink is discharged onto a sheet of paper on which a registration mark that serves as a reference for identifying an image formation position is printed, such that the overcoating ink is superimposed on the image, the ink jet recorder comprising:
 a conveying mechanism that conveys the sheet of paper;   a recording head that functions to discharge the overcoating ink onto a printing surface of the sheet of paper;   a reader that is arranged upstream, in a paper-conveying direction, of the recording head and that reads the registration mark printed on the sheet of paper that is conveyed;   a memory unit that stores data that is set in advance, based on a design correspondence relationship between a printing position of the registration mark and the image formation position in the sheet of paper, wherein the data is discharge data for identifying a discharge pattern of the overcoating ink discharged from the recording head;   a controller that performs the discharge control of the recording head based on the discharge data; and   a correction unit that corrects the discharge data based on information read for the registration mark,   wherein a plurality of the registration marks are printed on the sheet of paper,   the correction unit can obtain the position of each of the plurality of the registration marks as a measured position based upon information read by the reader, and   the correction unit corrects the discharge data corresponding to the specific image formation area surrounded by the plurality of the registration marks according to differences between a reference position of each of the plurality of the registration marks which is previously stored in the memory unit as a design position and the measured position of each of the registration marks read by the reader,   wherein the correction unit sequentially performs a first correction, which is a correction of the discharge data that corresponds to a first image formation area, and a second correction, which is a correction on the discharge data that corresponds to a second image formation area,   wherein the first image formation area is in front of the second image formation area in the paper-conveying direction, and   wherein the correction unit performs the second correction in parallel with the discharge control based on discharge data obtained by the first correction.   
     
     
       20. An ink jet recorder configured to perform an overcoating process, wherein an overcoating ink is discharged onto a sheet of paper on which a registration mark that serves as a reference for identifying an image formation position is printed, such that the overcoating ink is superimposed on the image, the ink jet recorder comprising:
 a conveying mechanism that conveys the sheet of paper;   a recording head that functions to discharge the overcoating ink onto a printing surface of the sheet of paper;   a reader that is arranged upstream, in a paper-conveying direction, of the recording head and that reads the registration mark printed on the sheet of paper that is conveyed;   a memory unit that stores data that is set in advance, based on a design correspondence relationship between a printing position of the registration mark and the image formation position in the sheet of paper, wherein the data is discharge data for identifying a discharge pattern of the overcoating ink discharged from the recording head;   a controller that performs the discharge control of the recording head based on the discharge data; and   a correction unit that corrects the discharge data based on information read for the registration mark,   wherein a plurality of the registration marks are printed on the sheet of paper,   the correction unit can obtain the position of each of the plurality of the registration marks as a measured position based upon information read by the reader, and   the correction unit corrects the discharge data corresponding to the specific image formation area surrounded by the plurality of the registration marks according to differences between a reference position of each of the plurality of the registration marks which is previously stored in the memory unit as a design position and the measured position of each of the registration marks read by the reader, and   wherein the recording head is configured to include nozzles that discharge an overcoating ink positioned in parallel along the paper-width direction, and, when a specific image formation area surrounded by respective measured positions of the registration marks is deformed with respect to a specific image formation area surrounded by respective reference positions of the registration marks, the correction unit corrects the discharge data so as to increase or decrease, on average, the number of nozzles for discharging an overcoating ink in the recording head in the paper-conveying direction or the paper-width direction in accordance with the deformation of the specific image formation area.   
     
     
       21. The ink jet recorder according to claim 19, wherein the memory unit stores, among the plurality of the registration marks which define the specific image formation area corresponding to the discharge data stored in advance, each position information of the registration mark positioned in front in the paper-conveying direction and of the registration mark positioned in back in the paper-conveying direction and information regarding a spacing interval between the recording head and the reader in the paper-conveying direction,
 wherein the correction unit performs, without performing a correction of the discharge data for at least a first sheet of paper when the distance between the registration mark positioned in front in the paper-conveying direction and the registration mark positioned in back in the paper-conveying direction is greater than or equal to the distance between the recording head and the reader in the paper-conveying direction, a correction of the discharge data for a subsequent sheet of paper, based on an actual positional relationship of the plurality of the registration marks.   
     
     
       22. The ink jet recorder according to claim 21, wherein, when correction is not performed for the first sheet of paper, the controller performs, without performing discharge control of the recording head on the first sheet of paper, discharge control of the recording head based on the discharge data as corrected for the subsequent sheet of paper. 
     
     
       23. The ink jet recorder according to claim 19, wherein the overcoating ink is an ultraviolet curable UV ink. 
     
     
       24. The ink jet recorder according to claim 23, further comprising:
 an ultraviolet-ray irradiation unit that is arranged downstream of the recording head in the paper-conveying direction and that cures, by irradiating the sheet of paper that is conveyed with an ultraviolet ray, the UV ink on the sheet of paper.