Printing Plate Removal via Backward Cylinder Rotation

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Solution Overview

Problem

Existing methods for changing printing plates in a printing press require multiple stops of plate cylinders, leading to increased downtime and inefficiency due to the need to stop all cylinders to remove plates, especially in systems with phase-offset cylinders connected through gear trains.

Innovation Solution

A method where the clamping device for the trailing edge of the printing plate is opened during backward rotation of the plate cylinder, allowing the plate to be gripped and removed by transport rollers without stopping the cylinder, and then pushed into a withdrawal chute, while the leading edge is clamped and released to facilitate continuous operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If all plate cylinders are stopped to remove printing plates, then plates can be removed safely and completely, but printing press downtime increases significantly

Engineering Contradiction:

Improvecomplete plate removalVSAvoidprinting press downtime

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The clamping device for the trailing edge is opened in advance during backward rotation of the plate cylinder, before the cylinder comes to a complete stop. This preliminary opening allows the printing plate to be gripped by transport rollers while the cylinder is still moving, enabling continuous operation and eliminating the need to stop all cylinders for plate removal

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system transitions from static plate removal (requiring complete stops) to dynamic plate removal where the plate is gripped and removed while the plate cylinder is still rotating backward. The transport rollers move at a speed higher than the backward rotation speed of the plate cylinder, allowing the plate to be carried away continuously without stopping the machine

Inventive Principle:

Principle #15Dynamics

2Productivity

If plate cylinders are stopped multiple times for plate removal, then all plates can be removed from phase-offset cylinders, but productivity decreases

Engineering Contradiction:

Improveplate changing speedVSAvoidcoordination of multiple cylinders

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The plate removal process is segmented into independent steps: opening the trailing edge clamping device during backward rotation, gripping the plate with transport rollers, and carrying it away. This segmentation allows each printing unit to operate independently without requiring synchronization stops of all phase-offset cylinders, simplifying the coordination complexity while improving productivity

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS8857335B2Method for changing printing plates

Publication Date: 2014.10.14 HEIDELBERGER DRUCKMASCHINEN AG

AI summary

A method and an apparatus for changing a printing plate on a printing press, include feeding the printing plate to a withdrawal chute of a plate changing apparatus by rotating the plate cylinder backward. Drivable transport rollers grip the printing plate and pull the latter out of a previously opened clamping device for the leading edge of the printing plate during the plate cylinder rotation, without the plate cylinder having to be stopped.