Image Forming Apparatus Gradation Patch Width Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing image forming apparatuses face challenges in maintaining real-time printing performance due to flare effects when forming gradation patches, which are affected by the proximity of density detection areas to gradation patches and limited margin areas, leading to impaired density correction and color accuracy.

Innovation Solution

The image forming apparatus employs a controller to form gradation patches with varying widths and colors, prioritizing higher gradation patches with wider sub-scanning widths and lower gradation patches with narrower widths, ensuring that the gradation patches are formed outside the image area to prevent flare while maintaining consistent sub-scanning widths across sheets, thereby enhancing real-time printing performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the gradation patch is simply increased (widened) to prevent the adverse effect due to flare, then the flare effect is reduced, but the margin area is limited and the real-time printing performance is compromised

Engineering Contradiction:
Improveflare effectVSAvoidreal-time printing performance
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent segments the gradation patch into multiple sub-scanning width regions, with different regions having different widths based on their position relative to the density detection area. This allows the patch to provide adequate separation from the detection area (reducing flare) while maintaining compact overall size (preserving margin area and printing performance).

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different sub-scanning widths to different regions of the gradation patch based on their local proximity to the density detection area. Regions closer to the detection area have narrower widths, while regions farther away have wider widths, optimizing both flare prevention and margin utilization locally across the patch.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If the gradation patch is formed outside the image area to prevent flare, then the reading accuracy is improved, but the margin area is reduced and printing performance is impaired

Engineering Contradiction:
Improvereading accuracyVSAvoidprinting performance
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent divides the gradation patch into multiple segments with different sub-scanning widths, allowing the patch to extend further from the image area (improving reading accuracy) while using variable widths to conserve margin area and maintain printing performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent utilizes the sub-scanning width dimension to create a gradient of patch widths across the patch area, allowing the patch to reach farther from the image area in terms of position while compensating with narrower widths in critical regions to preserve overall efficiency.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP4044572B1Image forming apparatus, method of forming gradation patch, and evaluation chart of the image forming apparatus
Publication Date: 2024.08.14 RICOH CO LTD
  • EP4044572B1 patent drawingFigure 1
  • EP4044572B1 patent drawingFigure 2
  • EP4044572B1 patent drawingFigure 3A~3B

AI summary

An image forming apparatus (200) includes an image forming device (210) and a control unit (300). The image forming device (240) is configured to form an image on a sheet (S). The control unit (300) is configured to acquire density information from image information of the image formed on the sheet (S), determine a width of each of a plurality of gradation patches (P) to be formed in a conveyance direction of the sheet (S) based on the density information, and cause the image forming device (210) to form the plurality of gradation patches (P) having different widths from each other in the conveyance direction of the sheet (S), in a margin area (SB, SC, SD) of the sheet (S).