Paper Type Detection in Image Forming Apparatus

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Solution Overview

Problem

Existing image forming apparatuses face challenges in accurately distinguishing paper types without sorting individual sheets from a bundle, which affects printing performance and user convenience.

Innovation Solution

An image forming apparatus equipped with a paper-type distinguishing device that irradiates light on a paper bundle and detects leaking light to determine paper characteristics, such as thickness, allowing for accurate paper type identification without separating individual sheets, and adjusts printing conditions accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a media sensor distinguishes paper type by detecting characteristics after paper separation, then measurement precision is improved, but productivity deteriorates due to the need to separate one piece of paper at a time

Engineering Contradiction:

Improvepaper type detection accuracyVSAvoidprinting speed

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent applies preliminary action by detecting paper type characteristics (thickness, light transmittance) while the paper bundle is still stacked in the paper feeding cassette, before the actual printing process begins. This allows the system to identify and select the appropriate paper type in advance, eliminating the need to separate individual sheets for detection and thereby maintaining high printing productivity.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If paper type is distinguished after one piece of paper reaches the media sensor, then measurement precision is improved, but loss of time increases due to delayed paper type identification

Engineering Contradiction:

Improvepaper type detection accuracyVSAvoidtime to identify paper type

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary detection of paper type characteristics by irradiating light through the stacked paper bundle in the cassette and measuring light transmittance before the printing process starts. This preliminary action identifies the paper type in advance, eliminating delays that would occur if detection were postponed until individual sheets reached the media sensor during printing.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If a CCD sensor detects paper characteristics from the side end face of a paper bundle, then productivity is improved by avoiding paper separation, but measurement precision deteriorates due to shading and light reflection issues

Engineering Contradiction:

Improveprinting speedVSAvoidpaper thickness detection accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

Instead of detecting paper characteristics from the side end face as in conventional approaches, the patent inverts the detection method by irradiating light through the paper bundle from the front surface and measuring light transmittance. This approach avoids the shading and light reflection problems associated with side-face detection, thereby improving measurement precision while maintaining productivity by keeping the paper bundle stacked.

Inventive Principle:

Principle #13The other way round (Inversion)

4Productivity

If image formation is performed before one piece of paper is separated from a paper bundle, then productivity is improved, but adaptability deteriorates as paper replacement becomes difficult

Engineering Contradiction:

Improveprinting speedVSAvoidpaper type flexibility

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The system performs preliminary detection and identification of paper type characteristics before image formation begins, while the paper bundle remains stacked in the cassette. This allows the system to adapt to different paper types and adjust printing parameters accordingly, maintaining both high productivity through continuous printing and adaptability through advance paper type identification.

Inventive Principle:

Principle #10Preliminary action

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

Enables accurate paper type identification and optimal printing conditions without interrupting the printing process, improving user experience and maintaining printing performance.

Implementation Method 1

a paper-type distinguishing device that irradiates light on a paper bundle and detects leaking light to determine paper characteristics, such as thickness

Methodology Applied

Scientific EffectLight transmission and leakage detection: Light

Data Source

PatentUS7970302B2Image forming apparatus and printing method therefor

Publication Date: 2011.06.28 KK TOSHIBA

AI summary

An image forming apparatus according to an embodiment of the present invention includes an apparatus main body, an image creating unit that is provided in the apparatus main body and creates an image to be printed on recording paper, a paper feeding mechanism on which plural pieces of the recording paper are stacked as a paper bundle, a paper-type distinguishing device that distinguishes a type of the recording paper from the paper bundle stacked on the paper feeding mechanism, and a printing unit that prints, according to the type of the recording paper distinguished by the paper-type distinguishing device, the image created by the image creating unit on the recording paper.