Printing Apparatus Conveyance Control for Fluctuation Suppression

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Solution Overview

Problem

Conveyance accuracy in printing apparatuses is compromised when switching between single and dual roller conveyance states due to bending and decentering issues, leading to fluctuations in conveyance amount and image quality.

Innovation Solution

A control unit recursively calculates the load acting on conveyance rollers in the second conveyance state, setting an initial value to 0, and adjusts the driving unit to suppress conveyance amount fluctuations during state transitions, using conveyance amount information and formulas to correct for bending and decentering effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conveyance state switching is implemented to control printing medium transport, then conveyance flexibility is improved, but conveyance amount accuracy deteriorates due to bending release and roller decentering

Engineering Contradiction:
Improveconveyance state switching capabilityVSAvoidconveyance amount accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The control unit performs preliminary correction calculations before conveyance state switching occurs. By recursively calculating the load on the downstream roller and determining the conveyance amount correction value in advance, the system prepares compensation values that will be applied when switching between single-roller and dual-roller conveyance states, thereby preventing conveyance amount fluctuations caused by bending release

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements a feedback mechanism where the control unit continuously monitors conveyance state transitions and recursively calculates load changes on the rollers. Based on this feedback information about the current conveyance state and roller loads, the control unit dynamically adjusts conveyance amount corrections to compensate for bending effects and maintain accurate positioning during state switching

Inventive Principle:
Principle #23Feedback

2Ease of manufacture

If roller outer diameter variation and decentering are present, then manufacturing cost is reduced, but conveyance amount accuracy deteriorates

Engineering Contradiction:
Improveroller manufacturing toleranceVSAvoidconveyance amount accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The control unit dynamically changes operational parameters by recursively calculating the actual load on each roller based on conveyance state and medium properties. Instead of requiring precise mechanical manufacturing, the system adjusts conveyance amount parameters in real-time based on calculated roller loads and bending states, compensating for manufacturing variations through software-based parameter optimization

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces mechanical precision requirements with computational correction. Rather than relying on precisely manufactured rollers with consistent outer diameters and perfect centering, the system uses recursive load calculations and software-based conveyance amount corrections to compensate for mechanical imperfections, substituting computational complexity for mechanical precision

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If bending correction based on conveyance amount difference is applied, then conveyance accuracy is improved, but response delay in bending occurrence is not accounted for

Engineering Contradiction:
Improveconveyance amount accuracyVSAvoidresponse delay in bending
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The control unit performs preliminary recursive load calculations that anticipate bending effects before they fully manifest. By calculating the load on the downstream roller and determining correction values in advance of state switching, the system accounts for the time delay in bending occurrence and applies corrections proactively rather than reactively

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements continuous feedback monitoring of conveyance state and recursive load calculation to detect bending occurrence timing. By monitoring the relationship between conveyance amount differences and roller loads in real-time, the control unit identifies when bending begins to occur and adjusts corrections dynamically, accounting for the response delay between conveyance state change and bending manifestation

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS9375955B2Printing apparatus and control method
Publication Date: 2016.06.28 CANON KK

AI summary

A printing apparatus includes a printing unit, a first and second conveying units conveying a printing medium, a driving unit driving the conveying units and a control unit controlling the driving unit. A load mutually acting on the conveying units through the medium in a conveyance state by the conveying units is recursively calculated for each predetermined conveyance unit while setting the initial value to 0. The driving unit is controlled based on the calculation result at the time of the transition to suppress a fluctuation in a conveyance amount at the time of the transition of the conveyance state of the medium from the conveyance state by the conveying units to a conveyance state only by the second conveying unit.