Sheet Feed Speed Detection for Stack Setting Failure

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Solution Overview

Problem

Existing sheet conveying devices in image forming apparatuses face challenges in accurately measuring the conveying speed of sheets due to potential misalignment or interference when multiple sheets are fed, leading to reduced accuracy in determining the setting failure state.

Innovation Solution

The solution involves a sheet conveying device with a lift portion, a sheet supply portion, and a detection portion that measures the conveying speed of sheets only when the stack is initially lifted, using speed information to determine if a setting failure state exists, and sets initial speed information based on type-specific averages to accurately detect maintenance needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple sheets are fed simultaneously, then productivity increases, but measurement precision of conveying speed deteriorates due to misalignment and interference

Engineering Contradiction:

Improvesheet feeding efficiencyVSAvoidconveying speed measurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by measuring the conveying speed of the first sheet before multiple sheets are fed simultaneously. The control unit stores this preliminary measurement as reference information and uses it to correct speed measurements taken during simultaneous multi-sheet feeding, thereby maintaining measurement precision while preserving productivity benefits

Inventive Principle:

Principle #10Preliminary action

2Productivity

If conveying speed is measured during simultaneous sheet feeding, then productivity is maintained, but reliability of setting failure detection deteriorates due to measurement inaccuracies

Engineering Contradiction:

Improvecontinuous operation capabilityVSAvoidsetting failure detection accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements feedback by continuously monitoring conveying speed and comparing it against the reference speed stored from preliminary measurements. When deviations exceed predetermined thresholds, the system reliably detects setting failures such as sheet misalignment or double feeding, maintaining both productivity and detection reliability through this closed-loop feedback mechanism

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP4671172A1Sheet conveying device capable of determining whether or not stack of sheets placed on lift portion is in setting failure state, image forming apparatus, and determination method

Publication Date: 2025.12.31 KYOCERA DOCUMENT SOLUTIONS INC

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AI summary

A sheet conveying device includes a sheet supply portion (28), a detection portion (25), an acquisition processing portion (42), and a determination processing portion (51). The sheet supply portion (28) supplies an uppermost sheet (SH1) in a stack of sheets (SB1) lifted by a lift portion (31) to a conveying path (27). The detection portion (25) detects the sheet (SH1) supplied by the sheet supply portion (28) on the conveying path (27). The acquisition processing portion (42) acquires, when the stack of sheets (SB1) is lifted by the lift portion (31), speed information related to a conveying speed of the sheet (SH1) by the sheet supply portion (28) using the detection portion (25). The determination processing portion (51) determines whether or not the stack of sheets (SB1) is in a setting failure state based on the speed information acquired by the acquisition processing portion (42).