Pad Printer Optical Adjustment System for Cliché Measurement

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Solution Overview

Problem

Existing pad printing machines are not compact enough to quickly and easily switch between different printing programs, and they often suffer from inaccuracies in cliché and workpiece positioning due to mechanical and measurement errors, leading to inconsistent color application.

Innovation Solution

A pad printing machine equipped with an optical adjustment system featuring a stationary camera system for measuring clichés and workpieces, allowing for precise determination of positional deviations and automatic calculation of correction values to ensure accurate color application without the need for complex mechanical adjustments or movement of camera systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a moving camera system is used to measure clichés, then the measurement can be performed during machine operation, but measurement errors occur due to positioning inaccuracies during movement

Engineering Contradiction:
Improvemeasurement efficiencyVSAvoidcliché position detection accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

Instead of moving the camera system to measure different clichés, the patent inverts the approach by keeping the camera system stationary and moving the clichés past the camera using a measuring station with a moving table. This eliminates positioning errors associated with moving the camera itself while still enabling measurement of multiple clichés during machine operation

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces a measuring station as an intermediary component between the stationary camera system and the clichés. This measuring station includes a moving table that transports clichés to the camera's field of view, allowing accurate measurement without requiring the camera to move or be precisely repositioned for each cliché

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the camera system is moved to measure different clichés, then all clichés can be measured, but mechanical stress on cameras increases and reliability decreases

Engineering Contradiction:
Improveability to measure multiple clichésVSAvoidcamera system long-term reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent reverses which component moves: instead of moving the camera system to adapt to different clichés, the clichés are moved to a stationary camera system. This eliminates mechanical stress on the cameras from repeated positioning while maintaining the ability to measure multiple clichés through the moving measuring station

Inventive Principle:
Principle #13The other way round (Inversion)

3Manufacturing precision

If complex mechanical adjustment mechanisms are used to position clichés and workpieces, then positioning accuracy can be achieved, but device complexity increases

Engineering Contradiction:
Improvecolor application precisionVSAvoidmechanical adjustment system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical adjustment mechanisms with an optical measurement system. Cameras capture images of clichés and workpieces, and a control unit processes these images to determine position deviations and calculate correction values, eliminating the need for complex mechanical positioning devices

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

Solution Approach 2:

The patent implements a feedback system where cameras continuously measure the actual positions of clichés and workpieces, the control unit compares these measurements with target positions to determine deviations, and correction values are calculated and applied to compensate for these deviations, achieving high precision without complex mechanical adjustments

Inventive Principle:
Principle #23Feedback

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

The solution enables a compact pad printing machine that can quickly switch between programs, reduces measurement errors, and ensures precise color alignment on workpieces by using stationary cameras to measure clichés and workpieces, improving long-term reliability and precision.

Implementation Method 1

a stationary camera system with at least one camera which is arranged stationary with respect to a cliché holder belonging to the cliché measurement system

Methodology Applied
Scientific EffectOptical imaging: Photography

Data Source

PatentEP3568303A1Pad printer
Publication Date: 2019.11.20 ILLINOIS TOOL WORKS INC

AI summary

The invention relates to a pad printer (50) having at least one cliché (31), held in a cliché carrier (30), and at least one printing pad (22) for receiving a print image from the at least one cliché (31) held in the cliché carrier (30). According to the invention, in order to create a pad printer (50) which is as compact as possible, on which different printing programs can be run and on which a change from one printing program to another printing program can be carried out simply and quickly, the pad printer (50) is assigned an optical adjustment system (1) which has a cliché-measuring system in the form of a measurement station (45) for measuring the at least one cliché (31) of the pad printer (50). The cliché-measuring system in the form of the measurement station (45) has a stationary camera system (3) having at least one camera which is fixed in position relative to a cliché holder (46) belonging to the cliché-measuring system.