Transfer Belt Registration Marks for Color Alignment and Density

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Solution Overview

Problem

Conventional image forming apparatuses face challenges in accurately detecting color registration errors due to complex causes such as mismatched color units, optical lens errors, and motion errors, leading to suboptimal image quality, and require separate sensors for color registration and image density, which are costly and complicated.

Innovation Solution

A color registration control apparatus with registration marks arranged on a transfer belt in a cross-scan direction, including scan and slanting direction components, and a registration sensor that radiates beams perpendicular to the belt's movement to detect registration and image density marks, allowing for simultaneous detection of color registration and image density errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If separate sensors are used for color registration and image density detection, then detection accuracy is improved, but device complexity and cost increase

Engineering Contradiction:

Improvedetection accuracyVSAvoidsensor configuration complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines color registration detection and image density detection into a single integrated sensor system. The sensor simultaneously detects registration marks (for color alignment) and density marks (for toner density), eliminating the need for separate sensors and reducing system complexity while maintaining detection accuracy

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The integrated sensor performs multiple functions: detecting color registration errors through registration marks and detecting image density through density marks. This multi-functional approach allows one sensor to replace what would traditionally require separate dedicated sensors for each measurement type

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Difficulty of detecting and measuring

If beams are radiated at an angle to detect registration marks, then detection capability is improved, but measurement precision deteriorates due to oblique incidence errors

Engineering Contradiction:

Improvedetection capabilityVSAvoidmeasurement accuracy

Core Design Contradiction:

Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

Instead of radiating beams at an oblique angle to achieve detection, the patent inverts the approach by radiating beams perpendicularly (at 90 degrees) to the transfer belt movement direction. This perpendicular incidence eliminates oblique angle errors while maintaining effective detection capability through the strategic arrangement of registration marks with scan and slanting direction components

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of manufacture

If registration marks lack slanting direction components, then manufacturing simplicity is improved, but manufacturing precision deteriorates due to inability to detect all error types

Engineering Contradiction:

Improvemark pattern simplicityVSAvoidcolor registration accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The registration marks incorporate asymmetric geometric features including both scan direction components (horizontal) and slanting direction components (diagonal at 45 degrees). This asymmetric design enables the detection of multiple error types (X-offset, Y-offset, printing width error, and skew) that would be impossible with symmetric or single-direction marks, thereby improving manufacturing precision

Inventive Principle:

Principle #4Asymmetry

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution enables accurate detection of color registration errors and image density, improving image quality by reducing detection errors and simplifying the sensor configuration, allowing for precise compensation of registration and density errors.

Implementation Method 1

receive beams reflected from the radiated registration mark to produce a detection signal

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS7658462B2Apparatus to control color registration and image density

Publication Date: 2010.02.09 HEWLETT PACKARD DEVELOPMENT COMPANY LP

AI summary

An apparatus to control color registration and image density and a method of calculating a color registration error. The apparatus includes registration marks formed on a transfer belt such that each of the registration marks includes a scan direction component and a slanting direction component at an angle with respect to both the scan direction and the cross-scan direction. The apparatus further includes image density marks formed on the transfer belt, having predetermined image densities, and a registration and image density sensor provided above the registration marks and the image density marks to radiate beams onto the registration marks and the image density marks. The sensor receives beams reflected from the registration marks and the image density marks to produce detection signals, and obtains registration information and image density information from the detection signals. Accordingly, X-offset, Y-offset, printing width error, and skew can be simultaneously compensated for using a single apparatus.