Image Forming Apparatus Density Correction via Preliminary Sheet Output

Solution Overview

Problem

Image forming apparatuses face challenges in obtaining precise density correction data without wasting resources, as density variations occur during image formation, leading to inefficient use of sheets and toner when forming test charts.

Innovation Solution

An image forming apparatus and method that outputs a sheet for first processing, followed by a sheet with a predetermined pattern for second processing, allowing for the obtaining of density correction data after the density characteristics of the output image have stabilized, thereby reducing resource wastage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If test charts are formed on many sheets to obtain precise density correction data, then measurement precision is improved, but loss of substance increases due to wasteful consumption of sheets and toner

Engineering Contradiction:

Improvedensity correction data precisionVSAvoidsheet and toner consumption

Core Design Contradiction:

Measurement precisionVSLoss of substance

Solution Approach 1:

The system performs preliminary actions by outputting a predetermined number of sheets before measuring density correction data. This preliminary output stabilizes the density characteristics of the image forming apparatus, ensuring that subsequent measurements are taken when the system is in a stable state, thereby improving measurement precision without requiring excessive test sheets.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system changes the parameter of sheet output quantity dynamically. Instead of always forming test charts on many sheets, the controller outputs a predetermined number of sheets based on the type of image formation, and only performs density measurement when the output sheet count reaches this predetermined number. This parameter adjustment reduces unnecessary sheet and toner consumption while maintaining measurement precision.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If test charts are formed on many sheets to stabilize density characteristics, then reliability of correction data is improved, but productivity decreases due to resource wastage

Engineering Contradiction:

Improvecorrection data reliabilityVSAvoidimage formation efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system performs preliminary actions by outputting a predetermined number of sheets before measuring density correction data. This preliminary output stabilizes the density characteristics of the image forming apparatus, ensuring that subsequent measurements are taken when the system is in a stable state, thereby improving measurement precision without requiring excessive test sheets.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system changes the parameter of sheet output quantity dynamically. Instead of always forming test charts on many sheets, the controller outputs a predetermined number of sheets based on the type of image formation, and only performs density measurement when the output sheet count reaches this predetermined number. This parameter adjustment reduces unnecessary sheet and toner consumption while maintaining measurement precision.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11448990B2Image forming apparatus, method of controlling same, and storage medium

Publication Date: 2022.09.20 CANON KK

AI summary

An image forming apparatus includes an image forming device to form an image on a sheet, and an image reading device to read an image from the sheet. A processing unit causes the image forming device to perform a predetermined image formation to form a first image for position correction of an output image and a second image for tone correction. A value of the position correction is obtained, based on a read image, and a tone correction value is obtained based on a read image from a second image sheet.