Imaging Apparatus Head Segmentation for Color Uniformity

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Solution Overview

Problem

Existing imaging apparatuses face challenges in reducing bidirectional color differences and image degradation due to variations in ink discharge amounts and head installation deviations, leading to complex head structures and increased manufacturing costs.

Innovation Solution

The imaging apparatus employs a recording head with nozzle arrays for cyan and black ink arranged in the same head, while yellow and magenta inks are separately arranged, with arrays shifted by half the nozzle pitch to reduce color unevenness and simplify installation, and uses a common liquid chamber to minimize ink mixing and supply complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If nozzle arrays for all colors are arranged in the same head, then installation is simplified and manufacturing precision is improved, but bidirectional color difference increases due to ink discharge order variations

Engineering Contradiction:
Improvehead installationVSAvoidcolor uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent segments the nozzle arrays by color: yellow and magenta nozzles are separated into different heads, while cyan and black nozzles are kept together in the same head. This segmentation allows the yellow/magenta heads to be used only in the outward scanning direction and the cyan/black head to be used in both directions, thereby eliminating bidirectional color differences while simplifying installation compared to having completely separate heads for each color.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies asymmetry by creating an asymmetric head configuration where not all color groups are treated equally. Specifically, yellow and magenta nozzles are separated into different heads while cyan and black remain together, creating an asymmetric arrangement that optimizes both installation ease and color uniformity by matching head usage patterns with scanning directions.

Inventive Principle:
Principle #4Asymmetry

2Manufacturing precision

If yellow and magenta nozzles are separated into different heads, then bidirectional color difference is reduced, but device complexity increases

Engineering Contradiction:
Improvecolor uniformityVSAvoidhead structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the nozzle arrays by color: yellow and magenta nozzles are separated into different heads, while cyan and black nozzles are kept together in the same head. This segmentation allows the yellow/magenta heads to be used only in the outward scanning direction and the cyan/black head to be used in both directions, thereby eliminating bidirectional color differences while simplifying installation compared to having completely separate heads for each color.

Inventive Principle:
Principle #1Segmentation

3Manufacturing precision

If multiple nozzle arrays are arranged in the same head, then manufacturing precision is improved, but ink mixing and supply complexity increase

Engineering Contradiction:
Improvelanding position accuracyVSAvoidliquid supply system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the liquid supply system to match the segmented head configuration. Each head (yellow, magenta, cyan/black) has its own dedicated liquid supply path, which simplifies the overall supply system by reducing the number of paths needed compared to having separate heads for all colors. The cyan and black nozzles sharing a head further reduces supply complexity by requiring only one supply path for these two colors.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP1881898B1Imaging apparatus
Publication Date: 2019.12.25 RICOH CO LTD
  • EP1881898B1 patent drawingFigure 1
  • EP1881898B1 patent drawingFigure 2
  • EP1881898B1 patent drawingFigure 3

AI summary

An imaging apparatus is disclosed that includes plural heads that are arranged in a main scanning direction, the heads including plural nozzle arrays that are arranged in the main scanning direction and configured to discharge droplets of recording liquids in at least three different colors including a yellow recording liquid. At least two of the nozzle arrays that are configured to discharge the yellow recording liquid are separately arranged in at least two of the heads. At least two of the nozzle arrays that are configured to discharge a first recording liquid of the recording liquids in a first color other than yellow are arranged together in one of the heads. At least two of the nozzle arrays that are configured to discharge a second recording liquid of the recording liquids in a second color other than yellow are arranged together in one of the heads.