Sheet Printer Edge Stacking via Registration Unit

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Solution Overview

Problem

Existing sheet printers face challenges in efficiently stacking printed sheets on a pallet, as the stacks are often positioned away from the pallet edges, making them unsuitable for direct engagement by finisher separators.

Innovation Solution

The method involves positioning a sheet with a corresponding edge at a pallet edge position inside the printer using a registration unit, allowing the stack to be formed directly at the pallet edge within the stacker, eliminating the need for additional repositioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the stacker positions the stack spaced apart from the pallet edges due to stacker restrictions, then the stacking process is simple and uses existing stacker components, but the stack cannot be directly engaged by finisher separators

Engineering Contradiction:
Improvestacking operation simplicityVSAvoidcompatibility with finisher separators
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The sheet is preliminarily positioned at the pallet edge position inside the printer before stacking occurs. The registration unit adjusts the sheet position in the lateral direction so that when the sheet is stacked by the stacker, it is already at the correct position for finisher engagement, eliminating the need for post-stack repositioning.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If additional loading aids are provided to reposition the stack outside the printer, then the stack can be positioned at the pallet edge for finisher engagement, but the process becomes more complex and time-consuming

Engineering Contradiction:
Improvecompatibility with finisher separatorsVSAvoidadditional loading aids and repositioning equipment
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The registration unit, which is already present in the printer for general sheet positioning purposes, is utilized to also position the sheet at the pallet edge position for stacking. This multi-functional use of existing equipment eliminates the need for additional specialized loading aids or repositioning devices.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If the sheet is positioned at the pallet edge position inside the printer using registration unit control, then the stack is formed directly at the pallet edge suitable for finishers, but the positioning control system becomes more complex

Engineering Contradiction:
Improveelimination of repositioning stepsVSAvoidpositioning control system
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The controller determines the actual position of the sheet inside the printer and compares it to the desired pallet edge position. Based on this feedback, the controller adjusts the registration unit to achieve precise positioning at the pallet edge, ensuring accurate stack formation for finisher compatibility.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4530237A1A method for stacking printed sheets aligned on an edge of a pallet
Publication Date: 2025.04.02 CANON PRODN PRINTING HLDG BV
  • EP4530237A1 patent drawingFigure 1~3
  • EP4530237A1 patent drawingFigure 4~7
  • EP4530237A1 patent drawingFigure 8~11

AI summary

In order to directly stack printed sheets at the edge of a pallet for improved compatibility with certain finishers, the present invention provides: A sheet printer (1) comprising: - a stacker (20; 120) at an end of a transport path of the printer (1), which stacker (20; 120) is configured to hold a pallet (30; 130) and to form a stack (16; 116) of printed sheets (S, S') thereon; - a registration unit (6, 12; 112) for adjusting an position and/or orientation of a sheet (S, S'), characterized in that - the stacker (20; 120) comprises a stack holder (29) for holding the pallet (30; 130) with one of its edges at a predetermined pallet edge position (P; P') in a first direction (X, Y); and - that a controller (38) is configured to control registration unit (6,12; 112) to position the sheet (S, S') with a corresponding edge at the predetermined pallet edge position (P; P') in the first direction (X, Y).