Inkjet Printer Edge Detection Thins Droplets to Suppress Bleeding

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Solution Overview

Problem

Existing inkjet printing techniques face challenges in suppressing bleeding and improving image sharpness, particularly in edge portions where ink droplets contact, leading to reduced visibility and quality issues.

Innovation Solution

An image processing apparatus that detects edges in grayscale images and generates print data by thinning out ink droplets in edge regions based on edge detection results, thereby controlling the recording amount for each pixel and improving image sharpness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If ink droplets are discharged densely to improve image density, then image density is improved, but bleeding occurs between adjacent ink droplets in edge portions

Engineering Contradiction:

Improveimage densityVSAvoidbleeding

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent applies different processing to different regions of the image by detecting edge portions and selectively thinning out ink droplets only in those regions. The edge portion determination unit identifies pixels at boundaries between different colors or densities, and the thinning out unit reduces the number of ink droplets specifically in these edge regions while maintaining full density in non-edge regions, thus preventing bleeding without compromising overall image density.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If ink droplets are thinned out in edge portions to suppress bleeding, then bleeding is suppressed, but image sharpness deteriorates

Engineering Contradiction:

ImprovebleedingVSAvoidimage sharpness

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies partial thinning out rather than complete removal of ink droplets in edge portions. The thinning out unit selectively reduces the number of ink droplets based on the pixel value thresholds, preserving enough ink to maintain image sharpness and visibility while sufficiently reducing density to prevent bleeding. This partial action approach balances the competing requirements of preventing bleeding and maintaining sharpness.

Inventive Principle:

Principle #16Partial or excessive action

3Object-affected harmful factors

If multi-pass printing is used to separate arrival timings of ink droplets, then bleeding is reduced, but printing time increases

Engineering Contradiction:

ImprovebleedingVSAvoidprinting time

Core Design Contradiction:

Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent segments the printing process by identifying edge portions and applying different droplet discharge strategies to different regions. Instead of using multiple passes for the entire image, the system divides the image into edge portions and non-edge portions, applying selective thinning out only to edge regions in a single pass. This segmentation approach achieves bleeding prevention without the time penalty of multi-pass printing.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250053348A1Image processing apparatus, image processing method, and non-transitory computer-readable medium

Publication Date: 2025.02.13 CANON KK

AI summary

An image processing apparatus is provided. The apparatus detects an edge in an N-arized image (N is a natural number not less than 2) representing a result of threshold-based processing for a grayscale image obtained from an input image. The apparatus generates the print data based on the input image and a detection result of the edge.