Lateral adjustment of print substrate based on a camera image

{
  "publication_number": "US2020376860A1",
  "country": "US",
  "kind": "A1",
  "title": "Lateral adjustment of print substrate based on a camera image",
  "abstract": "A printing device is provided comprising a camera to capture an image of at least a portion of a print substrate; a controller to determine a location of a portion of a side edge of the substrate from the image to determine a distance of the print substrate from a predetermined location; and adjustment apparatus to adjust the entire substrate laterally, relative to the direction of transport of the substrate, based on the determined location.",
  "claims": [
    "1. A printing device comprising: a camera to capture an image of at least a portion of a print substrate; a controller to determine a location of a portion of a side edge of the substrate from the image to determine a distance of the print substrate from a predetermined location; and adjustment apparatus to adjust the entire substrate laterally, relative to the direction of transport of the substrate, based on the determined location. 2. A printing device according to claim 1, wherein the controller is to determine a location of a corner of the substrate from the captured image and the adjustment apparatus is to adjust the entire substrate based on the determined location of the corner. 3. A printing device according to claim 2, wherein the controller is to determine a location of a portion of a leading edge of the substrate, and determine the location of the corner based on the locations of the portions of the side and leading edges. 4. The printing device of claim 1, further comprising feed apparatus and print apparatus, the camera and adjustment apparatus being located between the feed apparatus and the print apparatus. 5. The printing device of claim 3, wherein the substrate comprises a first sheet and the controller is to control the adjustment apparatus to adjust the entire first sheet such that the corner of the first sheet is relocated to a predetermined location and to further control the adjustment apparatus to adjust a subsequent second sheet such that a corresponding corner of the second sheet is relocated to the same predetermined location. 6. The printing device of claim 3, wherein the controller further is to detect a reference in the image and to determine the location of the portion of the side edge and/or the location of the portion of the leading edge as a location relative to that reference, the reference corresponding to a known location in the printing device. 7. The printing device of claim 1, further comprising memory to store information defining a plurality of search windows within the image for detecting edges located within the search windows, each search window being associated with a respective substrate size, the controller being coupled to the memory to select a search window appropriate for a size of the substrate to detect the portion of the side edge. 8. The printing device of claim 6, wherein the adjustment apparatus comprises nip rollers and a gripper, wherein the controller is to control the gripper and/or nip rollers to hold the substrate still while the camera captures the image and is to control the nip rollers to release the sheet to allow the gripper to adjust the substrate laterally based on the determined location and wherein the known location is a location on the gripper. 9. A method comprising: capturing, during registration of a print substrate in a printing device, an image of a portion of the substrate using a camera; determining a location of a portion of a boundary of the substrate from the image; determining a distance of the location of the portion of the boundary from a desired location; and adjusting the entire substrate laterally, relative to a direction of transport of the substrate, based on the determined distance to relocate the substrate such that the portion of the boundary is in the desired location, wherein the portion of the boundary is a portion of a side edge or a corner of the substrate. 10. A method according to claim 9, wherein determining a location of a boundary of the substrate comprises: determining a location and orientation of a portion of a side edge of the substrate; determining a location and orientation of a portion of a leading edge of the substrate; and extrapolating from the location and orientation of the portions of the side and leading edges to determine a location of a corner of the substrate. 11. The method of claim 9, wherein the capturing of the image and the adjusting is performed before printing on the substrate. 12. The method of claim 9, wherein the method further comprises detecting a reference within the image, corresponding to a reference location in the printing device, and wherein determining the location of the portion of the boundary comprises determining the location of the portion of the boundary relative to the reference location. 13. The method of claim 10, further comprising determining the size of the substrate and selecting a first and a second search window for detecting the portion of the side edge and the portion of the leading edge respectively based on the determined size of the substrate. 14. A non-transitory machine-readable storage medium encoded with instructions executable by a processor, the machine-readable storage medium comprising: instructions to capture, in a printing device, an image of at least a portion of a print substrate using a camera; instructions to determine a location of a portion of a side edge of the print substrate from the image; and instructions to determine a lateral adjustment, relative to a direction of transport of the substrate, from the determined location to relocate the print substrate to a desired location. 15. A non-transitory machine readable storage medium according to claim 14, further comprising: instructions to determine an orientation of the portion of a side edge; instructions to determine a location and orientation of a portion of a leading edge; and instructions to extrapolate from the location and orientation of the portions of the side and leading edges to determine a location of a corner of the substrate, and wherein the instructions to determine a lateral adjustment comprises instructions to determine a lateral adjustment, from the determined location of the corner, to relocate the substrate such that the corner is in a desired location."
  ],
  "cpc": [
    "B41J 11/0095",
    "B41J 11/0055",
    "B41J 11/42",
    "B41J 13/32",
    "B41J 2/04505",
    "B65H 11/007",
    "B65H 2511/20",
    "B65H 2511/413",
    "B65H 2553/42",
    "B65H 2701/1311",
    "B65H 2701/1315",
    "B65H 2701/1322",
    "B65H 7/06",
    "B65H 7/10",
    "B65H 9/002",
    "B65H 9/004",
    "B65H 9/103",
    "B65H 9/106"
  ],
  "assignees": [
    "HEWLETT PACKARD DEVELOPMENT CO"
  ],
  "filing_date": "2017-12-14",
  "publication_date": "2020-12-03",
  "priority_date": "2017-12-14",
  "application_number": "US-201716607195-A",
  "family_id": "66820514"
}