IMAGE FORMING APPARATUS, IMAGE FORMING METHOD, AND IMAGE FORMING PROGRAM

• US 20100103441A1
• Filed: 10/21/2009
• Published: 04/29/2010
• Est. Priority Date: 10/22/2008
• Status: Abandoned Application

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Ooya, Hiroshi
• Application Number:
  US12/603,246
• Publication Number:
  US 20100103441A1
• Time in Patent Office: Days
• US Class Current: 358/1.900
• CPC Class Codes: H04N 1/047 Detection, control or error compensation of scanning velocity or position H04N1/0402 and H04N1/17 take precedence
• CPC Class Codes: H04N 1/1135 for the main-scan only
• CPC Class Codes: H04N 1/12 using the sheet-feed movement or the medium-advance or the drum-rotation movement as the slow scanning component, e.g. arrangements for the main-scanningsheet-feed movement by translatory movement of a flat picture-bearing surface H04N1/1008; main-scanning using oscillating or rotating mirrors H04N1/113; using multi-element arrays H04N1/19
• CPC Class Codes: H04N 1/1911 Simultaneously or substantially simultaneously scanning picture elements on more than one main scanning line, e.g. scanning in swaths
• CPC Class Codes: H04N 1/60 Colour correction or control H04N1/54 takes precedence
• CPC Class Codes: H04N 2201/0082 Image hardcopy reproducer H04N2201/0091 - H04N2201/0094 take precedence
• CPC Class Codes: H04N 2201/0098 User intervention not otherwise provided for, e.g. placing documents, responding to an alarm
• CPC Class Codes: H04N 2201/03162 Original guide plate
• CPC Class Codes: H04N 2201/04787 by changing or controlling the addresses or values of pixels, e.g. in an array, in a memory, by interpolation
• CPC Class Codes: H04N 2201/04789 in the main-scan direction
• CPC Class Codes: H04N 2201/04791 in the sub-scan direction
• CPC Class Codes: H04N 2201/04793 using stored control or compensation data, e.g. previously measured data

Abstract

A printer not optically correcting bends and inclinations of scanning lines needs to execute such control as to electrically correct them. However, a conventional correction method has a problem that this correction causes an image defect such as an image streak or an uneven density in a specific area. A correction method of the present invention, when an input image has only one color, executes only correction by a second correction component which corrects distortions in a main scanning direction without executing correction by a first correction component which corrects bends and inclinations in a sub-scanning direction, and when an input image has two or more colors, executes both of correction by the first correction component and correction by the second correction component. This control can reduce the frequency of occurrence of an image defect.

Claims

1. An image forming apparatus which causes each of a plurality of light beams to scan in a main scanning direction and a sub-scanning direction vertical to the main scanning direction to form an image having a plurality of colors, the apparatus comprising:

a first correction component configured to correct bends and inclinations in the sub-scanning direction by performing conversion of image data so as to cancel bends and inclinations of the shapes of scanning lines when causing the light beams to scan in the main scanning direction;

a second correction component configured to correct distortions in the main scanning direction of scanning lines; and

a control component configured to execute both of correction by the first correction component and correction by the second correction component when an input image has two or more colors, and to execute only correction by the second correction component when an input image has only one color.

2. The image forming apparatus of claim 1, further comprising:

a print method instruction component configured to be capable of instructing whether to execute each of correction by the first correction component and correction by the second correction component; and

a correction execution condition determining component configured to determine whether the print method instruction component has received an instruction whether to execute each of correction by the first correction component and correction by the second correction component,

wherein the control component controls execution of correction by the first correction component and correction by the second correction component, based on the determination by the correction execution condition determining component.

3. The image forming apparatus of claim 2, further comprising,

a measuring component configured to measure information about a bend, inclination, and distortion of a light beam of each color when causing each of the plurality of light beams to scan in the main scanning direction, wherein:

the correction execution condition determining component further determines whether a bend and inclination of a light beam of each color measured by the measuring component are less than a reference value and whether a distortion of a light beam of each color measured by the measuring component is less than a reference value; and

the control component performs control so as not to execute correction by the first correction component when the correction execution condition determining component has determined that a bend and inclination of a light beam of each color measured by the measuring component are less than a reference value, and performs control so as not to execute correction by the second correction component when the correction execution condition determining component has determined that a distortion of a light beam of each color measured by the measuring component is less than a reference value.

4. The image forming apparatus of claim 3, wherein the correction execution condition determining component gives priority to a correction execution condition instructed by the print method instruction component when the correction execution condition instructed by the print method instruction component is different from a correction execution condition determined from a measurement result measured by the measuring component.

5. An image forming method of an image forming apparatus which causes each of a plurality of light beams to scan in a main scanning direction and a sub-scanning direction vertical to the main scanning direction to form an image having a plurality of colors, the method comprising the steps of:

a first correction step correcting bends and inclinations in the sub-scanning direction by performing conversion of image data so as to cancel bends and inclinations of the shapes of scanning lines caused when causing the light beams to scan in the main scanning direction;

a second correction step correcting distortions in the main scanning direction of scanning lines; and

a control step controlling execution of both of correction by the first correction step and correction by the second correction step when an input image has two or more colors and execution of only correction by the second correction step when the input image has only one color.

6. A program on a computer readable medium for an image forming method of an image forming apparatus which causes each of a plurality of light beams to scan in a main scanning direction and a sub-scanning direction vertical to the main scanning direction to form an image having a plurality of colors, the method comprising the steps of:

a first correction step correcting bends and inclinations in the sub-scanning direction by performing conversion of image data so as to cancel bends and inclinations of the shapes of scanning lines caused when causing the light beams to scan in the main scanning direction;

a second correction step correcting distortions in the main scanning direction of scanning lines; and

a control step controlling execution of both of correction by the first correction step and correction by the second correction step when an input image has two or more colors and execution of only correction by the second correction step when the input image has only one color.