Web Registration Control Mode Switching in Continuous Feed Printers

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Solution Overview

Problem

Existing moving web printing systems face inaccuracies in web velocity calculations during transitions, particularly during acceleration and deceleration, due to induced transients in low pass and high pass filters used in double reflex registration methods.

Innovation Solution

A system and method that selectively employs either a single reflex or double reflex registration control method based on web velocity, using multiple encoders and converters to generate linear velocity signals, with a controller adjusting these signals to minimize transient errors and ensure accurate web velocity calculations during steady-state and transitional periods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the double reflex registration method is used to improve image registration accuracy, then manufacturing precision is improved, but measurement precision deteriorates during web acceleration and deceleration due to induced transients in filters

Engineering Contradiction:

Improveimage registration accuracyVSAvoidweb velocity calculation accuracy

Core Design Contradiction:

Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The system dynamically switches between single reflex and double reflex registration methods based on web velocity conditions. During steady-state operation, the double reflex method is used for high precision image registration. During acceleration or deceleration transitions, the system switches to the single reflex method to avoid filter transient errors, thereby maintaining measurement precision across varying operating conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the registration control parameter (method selection) based on web velocity thresholds. When web velocity is below a threshold indicating transition periods, the single reflex method is activated. When web velocity exceeds the threshold indicating steady-state operation, the double reflex method is activated. This parameter change resolves the contradiction by selecting the appropriate method for each operating condition.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If the single reflex method is used to simplify the registration control system, then device complexity is reduced, but manufacturing precision deteriorates due to insufficient velocity measurement accuracy

Engineering Contradiction:

Improveregistration control system complexityVSAvoidimage registration accuracy

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The system dynamically adapts the registration method based on operational conditions. During steady-state web movement, the double reflex method is employed to achieve high manufacturing precision. During transitions, the single reflex method is used to maintain system simplicity and avoid errors. This dynamic adaptation allows the system to achieve high precision when needed without permanently increasing device complexity.

Inventive Principle:

Principle #15Dynamics

3Measurement precision

If filters are used to equalize angular velocity signals to improve measurement precision, then measurement precision is improved, but harmful factors increase due to induced transients during web velocity transitions

Engineering Contradiction:

Improveangular velocity signal accuracyVSAvoidinduced transients in filters

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The system extracts and removes the harmful filter transient effect by switching to an alternative measurement method (single reflex) when web velocity is in transition. This eliminates the harmful factor entirely during problematic operating conditions, rather than attempting to suppress it within the same system architecture.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The system converts the harmful transient effect into a beneficial operational characteristic by using the transition detection to trigger a mode switch. The transient condition itself becomes the trigger for selecting the appropriate registration method, transforming the harmful effect into a useful control signal for maintaining overall system accuracy.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS8328315B2System and method for switching registration control modes in a continuous feed printer

Publication Date: 2012.12.11 GENESEE VALLEY INNOVATIONS LLC

AI summary

A method enables a printing system to be operated in one of two registration control modes. The method includes operating at least one marking station with reference to a first velocity measurement of a web moving along a web path in response to a first registration control mode being active, the first velocity measurement corresponding to an angular velocity signal obtained from only a first roller in a web path, and operating the at least one marking station with reference to a second velocity measurement of the web moving along the web path in response to a second registration control mode being active, the second velocity measurement corresponding to at least two angular velocity signals obtained from at least the first roller and a second roller in the web path.