Calibration method for density in image forming apparatus

• US 7,061,648 B2
• Filed: 01/16/2002
• Issued: 06/13/2006
• Est. Priority Date: 01/17/2001
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Nakajima, Nobuyuki, Tsuchiya, Masakazu
• Primary Examiner(s): Garcia, Gabriel I.
• Application Number:
  US10/046,578
• Publication Number:
  US 20020113984A1
• Time in Patent Office: 1,609 Days
• Field of Search: 358/1.1, 358/1.9, 358/1.13, 358/1.15, 358/504, 358/518, 382/162, 382/165, 382/167
• US Class Current: 358/1.9
• CPC Class Codes: H04N 1/4078 using gradational references, e.g. grey-scale test pattern analysis
• CPC Class Codes: H04N 1/6033 using test pattern analysis H04N1/6055 takes precedence

Abstract

Calibration associated with output density correction of a printer is effected by software calibration manipulated by the user and device calibration automatically performed by the printer, and, regarding these calibrations, high accurate calibration in which dither patterns for binarizing processing are matched to each other is effected.

In a system in which either one of halftone patterns A, B, C and D as dither patterns can be used, regarding fewer number of patterns A and B, second calibration tables are created by correcting first calibration tables based on the software calibration by using correction data of engine characteristics based on the device calibration. Among the usable halftone patterns, the calibration table corresponding to the pattern A or B is selected in accordance with the set halftone pattern, and the output density correction by using the selected table.

Claims

1. A calibration method for a printer, comprising:

a patch outputting step for effecting print output of patch, from a print apparatus, on the basis of patch data based on a predetermined number of binarizing processing conditions fewer than plural binarizing processing conditions usable for generating data for print output;

a first acquiring step for acquiring first print output characteristics information and first calibration information for the predetermined number of binarizing processing conditions on the basis of read result of said patch and the patch data;

a measuring step for effecting output of said patch and measurement of said patch on the basis of the patch data based on the predetermined number of binarizing processing condition in said print apparatus at a predetermined timing;

a second acquiring step for acquiring second print output characteristics information for the predetermined number of binarizing processing condition on the basis of measured result of said patch and the patch data based on the predetermined number of binarizing processing condition;

a generating step for generating correction data for the predetermined number of binarizing processing condition on the basis of the first print output characteristics information and the second print output characteristics information; and

a third acquiring step for acquiring second calibration information for the predetermined number of binarizing processing conditions by correcting the first calibration information on the basis of the generated correction data.

2. A method according to claim 1, wherein the binarizing processing is a dither method.

3. A method according to claim 2, wherein the plural binarizing processings effect binarizing processing on the basis of different halftone patterns.

4. A method according to claim 1, wherein the calibration information is information of gamma correction table, and, in said measuring step, before the output of said patch, maximum density of the print output characteristics in said print apparatus is adjusted to a predetermined value.

5. A method according to claim 1, wherein, in said second acquiring step, if the acquisition of the first calibration information is not effected, the second calibration information is acquired by using only the second print output characteristics information.

6. A print system including a print apparatus and a host apparatus for controlling print of said print apparatus and adapted to make point output characteristics of said print apparatus constant, comprising:

patch outputting means for effecting print output of patch, from a print apparatus, on the basis of patch data based on a predetermined number of binarizing processing conditions fewer than plural binarizing processing conditions usable for generating data for print output;

first acquiring means for acquiring first print output characteristics information and first calibration information for the predetermined number of binarizing processing conditions on the basis of read result of said patch and the patch data;

patch output measuring means for effecting output of said patch and measurement of said patch on the basis of the patch data based on the predetermined number of binarizing processing conditions in said print apparatus at a predetermined timing;

characteristics information acquiring means for acquiring second print output characteristics information for the predetermined number of binarizing processing conditions on the basis of measured result of said patch and the patch data based on the predetermined number of binarizing processing conditions;

correction data generating means for generating correction data for the predetermined number of binarizing processing conditions on the basis of the first print output characteristics information and the second print output characteristics information;

second acquiring means for acquiring second calibration information for the predetermined number of binarizing processing conditions by correcting the first calibration information on the basis of the generated correction data;

selection means for selecting calibration information corresponding to one of the predetermined number of binarizing processing conditions fewer than the plural binarizing processing conditions, in accordance with set binarizing processing condition;

correction means for correcting print output characteristics for the data by using the selected calibration information; and

processing means for effecting binarizing processing of the data under the binarizing processing condition corresponding to the selected calibration information.

7. A print system according to claim 6, wherein the binarizing processing is a dither method.

8. A print system according to claim 7, wherein the binarizing processing effects binarizing processing on the basis of different halftone pattern.

9. A print system according to claim 6, wherein the calibration information is information of gamma correction table, and, in said patch output measuring means, before the output of said patch, maximum density of the print output characteristics in said print apparatus is adjusted to a predetermined value.

10. A print system according to claim 6, wherein, in said characteristics information acquiring means, if the acquisition of the first calibration information is not effected, the second calibration information is acquired by using only the second print output characteristics information.

11. A print apparatus comprising:

first storing means for storing first print output characteristics information and first calibration information acquired on the basis of read result of patch and patch data and downloaded from a host apparatus with respect to a predetermined number of binarizing processing conditions fewer than plural binarizing processing conditions usable for generating data for print output, said patch being outputted from said print apparatus on the basis of said patch data based on said predetermined number of binarizing processing conditions;

patch output measuring means for effecting output of said patch and measurement of said patch on the basis of the patch data based on the predetermined number of binarizing processing conditions at a predetermined timing;

characteristics information acquiring means for acquiring second print output characteristics information for the predetermined number of binarizing processing conditions on the basis of measured result of said patch and the patch data based on the predetermined number of binarizing processing conditions;

second storing means for storing the second print output characteristics information and second calibration information for the predetermined number of binarizing processing conditions;

correction data generating means for generating correction data for the predetermined number of binarizing processing conditions on the basis of the first print output characteristics information stored in said first storing means and the second print output characteristics information stored in said second storing means;

calibration information generating means for generating the second calibration information for the predetermined number of binarizing processing conditions by correcting the first calibration information on the basis of the correction data generated by said correction data generating means;

selection means for selecting calibration information corresponding to one of the predetermined number of binarizing processing conditions fewer than the plural binarizing processing conditions, in accordance with a binarizing processing condition set in binarizing processing;

correction means for correcting print output characteristics for the data by using the selected calibration information; and

processing means for effecting binarizing processing of the data under the binarizing processing condition corresponding to the selected calibration information.

12. A storage medium which stored a program readable by an information processing apparatus, said program comprising:

a patch outputting step for effecting print output of patch, from a print apparatus, on the basis of patch data based on a predetermined number of binarizing processing conditions fewer than plural binarizing processing conditions usable for generating data for print output;

a first acquiring step for acquiring first print output characteristics information and first calibration information for the predetermined number of binarizing processing conditions on the basis of read result of said patch and the patch data;

a measuring step for effecting output of said patch and measurement of said patch on the basis of the patch data based on the predetermined number of binarizing processing conditions in said print apparatus at a predetermined timing;

a second acquiring step for acquiring second print output characteristics information for the predetermined number of binarizing processing conditions on the basis of measured result of said patch and the patch data based on the predetermined number of binarizing processing conditions;

a generating step for generating correction data for the predetermined number of binarizing processing conditions on the basis of the first print output characteristics information and the second print output characteristics information; and

a third acquiring step for acquiring second calibration information for the predetermined number of binarizing processing conditions by correcting the first calibration information on the basis of the generated correction data.

13. A program stored in a computer readable medium for calibration processing for making print output characteristics of a print apparatus constant, said program including codes for executing processing comprising the steps of:

effecting print output of patch, from a print apparatus, on the basis of patch data based on a predetermined number of binarizing processing conditions fewer than plural binarizing processing conditions usable for generating data for print output;

acquiring first print output characteristics information and first calibration information for the predetermined number of binarizing processing conditions on the basis of read result of said patch and the patch data;

effecting output of said patch and measurement of said patch on the basis of the patch data based on the predetermined number of binarizing processing conditions in said print apparatus at a predetermined timing;

acquiring second print output characteristics information for the predetermined number of binarizing processing conditions on the basis of measured result of said patch and the patch data based on the predetermined number of binarizing processing conditions;

generating correction data for the predetermined number of binarizing processing conditions on the basis of the first print output characteristics information and the second print output characteristics information; and

acquiring second calibration information for the predetermined number of binarizing processing conditions by correcting the first calibration information on the basis of the generated correction data.