Handheld printer minimizing printing defects

• US 7,682,017 B2
• Filed: 05/10/2006
• Issued: 03/23/2010
• Est. Priority Date: 05/10/2006
• Status: Expired due to Fees

• Current Assignee: Lexmark International Incorporated (Ninestar Corporation)
• Original Assignee: Lexmark International Incorporated (Ninestar Corporation)
• Inventors: Reed, William H., Stout, Barry B., Robertson, Douglas
• Primary Examiner(s): Shah; Manish S
• Application Number:
  US11/431,883
• Publication Number:
  US 20070263063A1
• Time in Patent Office: 1,413 Days
• Field of Search: 347/109, 347/108
• US Class Current: 347/109
• CPC Class Codes: B41J 2/2132 Print quality control characterised by dot disposition, e.g. for reducing white stripes or banding methods for local corrections by dot omission, image edge enhancement, or multi-pass mask selection G06K15/102; colour conversion H04N1/40
• CPC Class Codes: B41J 3/36 for portability , i.e. hand-held printers or laptop printers B41J3/4075 takes precedence
• CPC Class Codes: H04N 1/107 with manual scanning
• CPC Class Codes: H04N 1/40025 Circuits exciting or modulating particular heads for reproducing continuous tone value scales H04N1/401, H04N1/407 take precedence
• CPC Class Codes: H04N 2201/0414 Scanning an image in a series of overlapping zones
• CPC Class Codes: H04N 2201/0471 using dedicated detectors
• CPC Class Codes: H04N 2201/04737 by detecting the scanned medium directly, e.g. a leading edge

Abstract

Methods and apparatus include a handheld printer manipulated back and forth by an operator during use to print an image. An inkjet printhead of the printer has a plurality of fluid firing actuators arranged in a substantial column. A controller communicates with the printhead to identify active actuators given to fire at a particular time during use to print the image. However, to prevent unsightly print quality from occurring during overlapping adjacent print swaths, for example, certain of the identified actuators are prevented from firing. Especially, actuators in the column further from a center of the column fire less frequently than those closer to the center. A position sensor is also used to locate the printhead relative to the image. The controller correlates the position to the printhead and actuators and fires the active actuators or not.

Claims

1. A handheld printer, comprising:

an inkjet printhead having a plurality of fluid firing actuators; and

a controller communicating with the printhead to identify ones of the actuators requiring firing to print an image and to prevent firing some of the identified ones of the actuators to avoid print banding during use;

wherein the controller correlates the location of the printhead to the image and proportions the actuators in the column further from a center of the column to fire less frequently than the actuators closer to the center.

2. The handheld printer of claim 1, wherein the controller identifies the ones of the actuators based on an actuator position in a column of fluid firing actuators.

3. The handheld printer of claim 2, wherein the controller causes firing select actuators in the column of fluid firing actuators at a terminal position less frequently during use than at other positions of the column of fluid firing elements.

4. The handheld printer of claim 2, wherein the controller is further configured to proportion firing select actuators closer to a center position of the column of fluid firing actuators more frequently than for other actuators further from the center position.

5. The handheld printer of claim 1, further including an optical sensor communicating with the controller to provide printhead location during use.

6. The handheld printer of claim 1, further including a stored to-be-printed image.

7. The handheld printer of claim 6, wherein the stored to-be-printed image has a dynamic update capability.

8. A handheld printer to be manipulated back and forth by an operator during use to print an image, comprising:

a hand maneuverable housing for an operator;

an inkjet printhead in the housing having a plurality of fluid firing actuators arranged in a substantial column;

a controller communicating with the printhead to cause firing or not of ones of the actuators during use when adjacent print swaths of the housing overlap;

a position sensor communicating with the controller to provide a location of the printhead during use,

wherein the controller correlates the location of the printhead to the image and proportions the actuators in the column further from a center of the column to fire less frequently than others of the actuators closer to the center.

9. The handheld printer of claim 8, wherein the controller has a dynamic update ability to alter the image during printing.

10. The handheld printer of claim 9, wherein the controller adds noise.

11. The handheld printer of claim 8, wherein the controller is capable of evaluating whether the image is completely printed.

12. A method of printing an image with a handheld printer having an inkjet printhead in a housing, comprising:

determining whether fluid firing actuators of the printhead should fire in printing the image; and

if the actuators should fire, identifying ones of the actuators to avoid firing based on a position in a column of fluid firing actuators, wherein the controller correlates the location of the printhead to the image and proportions the actuators in the column further from a center of the column to fire less frequently than the actuators closer to the center.

13. The method of claim 12, further including manipulating the housing relative to a substrate.

14. The method of claim 13, further including correlating a position of the printhead to the image.

15. The method of claim 12, wherein the identifying further includes proportioning the actuators in the column further from a center of the column to fire less frequently than others of the actuators closer to the center.

16. The method of claim 12, wherein the determining further includes dynamically updating a stored representation of the image.

17. The method of claim 16, further including adding noise.