Sheet Feed Speed Detection Under Lifted Stack Conditions

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Solution Overview

Problem

Existing sheet conveying devices in image forming apparatuses experience a lowering of acquisition accuracy in measuring sheet conveying speed due to sheets being pulled from the stack before the lift mechanism is fully engaged, leading to inaccurate speed measurements.

Innovation Solution

The solution involves acquiring speed information only when the stack of sheets is lifted by the lift portion, using the detection portion to measure the conveying speed of the sheet supply portion, and setting initial speed information based on specific conditions to improve accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If speed information is acquired continuously using the detection portion, then more speed data can be collected, but measurement accuracy decreases when sheets are pulled before the lift mechanism is fully engaged

Engineering Contradiction:
Improveconveying speed measurement accuracyVSAvoidtime for speed information acquisition
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary verification to ensure the lift portion has fully engaged the stack of sheets before acquiring speed information. This preliminary check prevents inaccurate measurements by ensuring the measurement condition is properly established before data collection begins.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the acquisition parameter from continuous speed measurement to conditional speed measurement, where measurement only occurs when specific conditions are met (lift portion fully engaged). This parameter change ensures measurement accuracy while reducing unnecessary data collection.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the detection portion measures conveying speed at any time, then measurement frequency increases, but accuracy lowers due to unstable stack conditions

Engineering Contradiction:
Improvespeed measurement frequencyVSAvoidconveying speed measurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system changes the measurement parameter from unrestricted continuous measurement to conditional measurement, where the detection portion only acquires speed information when the lift portion has fully engaged the stack. This maintains productivity while ensuring measurement accuracy through proper condition verification.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system uses feedback from the lift portion's engagement status to control when speed measurement occurs. The detection portion receives feedback about whether the stack is properly engaged, and only proceeds with measurement when the feedback indicates stable conditions.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4671171A1Sheet conveying device capable of suppressing lowering of acquisition accuracy of sheet conveying speed, image forming apparatus, and acquisition method
Publication Date: 2025.12.31 KYOCERA DOCUMENT SOLUTIONS INC
  • EP4671171A1 patent drawingFigure 1
  • EP4671171A1 patent drawingFigure 2
  • EP4671171A1 patent drawingFigure 3

AI summary

A sheet conveying device includes a lift portion (31), a sheet supply portion (28), a detection portion (25), and an acquisition processing portion (42). The lift portion (31) lifts a stack of sheets (SB1). The sheet supply portion (28) includes a conveying member (22) which rotates while being in contact with an upper surface of the stack of sheets (SB1) lifted by the lift portion (31), and supplies a sheet (SH1) that comes into contact with the conveying member (22) 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, only 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).