Print Media Border Detection via Cutter Friction

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Solution Overview

Problem

Image forming apparatuses face challenges in precisely determining the position and width of a continuous roll print medium within the print zone, leading to potential smearing or hardware damage due to inaccurate printing, especially when the medium is not aligned or centered.

Innovation Solution

The apparatus uses a cutter with an encoder and controller to measure friction changes as the cutter interacts with the medium, allowing for precise identification of border positions and calculation of the medium's width and position, even if it's not initially aligned, by associating friction changes with the cutter's position using PWM signals and encoder data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If mechanical alignment methods are used to center the print medium, then positioning accuracy is improved, but device complexity increases

Engineering Contradiction:
Improveborder position detection accuracyVSAvoidalignment mechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical alignment systems with a friction-based detection system. Instead of using mechanical sensors or visual systems to detect border positions, the invention uses friction changes between the cutter and print medium to identify borders, significantly simplifying the device while maintaining detection accuracy

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

Solution Approach 2:

The print medium itself provides the alignment information through its physical interaction with the cutter. The friction changes generated during cutting inherently indicate border positions, eliminating the need for external alignment mechanisms or additional sensing systems

Inventive Principle:
Principle #25Self-service

2Device complexity

If friction measurement is used to identify border positions, then device complexity is reduced, but measurement precision may be affected by friction variations

Engineering Contradiction:
Improvedetection system simplicityVSAvoidborder position detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The system continuously monitors friction changes during the cutting process and uses this feedback to identify border positions. The controller adjusts based on real-time friction measurements, enabling accurate border detection despite variations in friction conditions

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The invention monitors changes in friction parameters during cutting rather than absolute friction values. By detecting transitions and variations in friction characteristics, the system can accurately identify border positions even when baseline friction levels vary

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the print medium is not aligned or centered in the print zone, then adaptability is improved, but manufacturing precision deteriorates due to inaccurate printing

Engineering Contradiction:
Improveprint medium positioning flexibilityVSAvoidprinting accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The system performs border position detection and calculation of print medium position and width before the actual printing process. This preliminary measurement allows the system to adapt to any print medium positioning and adjust printing parameters accordingly, ensuring precision regardless of initial alignment

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention implements a dynamic system that can accommodate variable print medium positions and widths. By measuring actual border positions and calculating the required adjustments, the system dynamically adapts the printing process to maintain precision even when the medium is not pre-aligned

Inventive Principle:
Principle #15Dynamics

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

This method enables precise alignment and positioning of the print medium, allowing for reduced or no margins during printing, preventing smearing and hardware damage by accurately determining the medium's width and position within the print zone.

Implementation Method 1

measuring friction changes as a result of the cutter contacting the print medium

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3455080B1Identifying print media borders
Publication Date: 2020.09.30 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3455080B1 patent drawingFigure 1
  • EP3455080B1 patent drawingFigure 2
  • EP3455080B1 patent drawingFigure 3A~3B

AI summary

Devices and methods for identifying border positions of print media in image forming apparatuses are disclosed. In an example method print media are advanced in a feeding direction to reach a cutting position, a cutter is advanced in a cutting direction, perpendicular to the feeding direction to cut the print media, changes in friction are identified when the cutter contacts the print media, positions of the cutter are identified when the changes in friction are identified and border positions are determined based on the identifying of cutter positions.