Duplex Printing Loop Sheet Orientation Control

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Solution Overview

Problem

Existing printing systems face inefficiencies when trying to productively print duplex sheets in combination with specialty sheets, as the duplex loop needs to be emptied when printing specialty sheets, leading to unproductive system conditions.

Innovation Solution

The introduction of a second turn station near the output section and a logic module in the control unit to manage the orientation of sheets, allowing specialty sheets to be treated as pass-throughs during the printing process, maintaining the duplex loop's productivity by ensuring all sheets, including simplex and duplex sheets, are fed through the loop without unnecessary turns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the duplex loop is emptied when printing specialty sheets, then the specialty sheets can be printed correctly, but the system becomes unproductive

Engineering Contradiction:
Improvecorrect printing of specialty sheetsVSAvoidsystem productivity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the sheet handling process into different paths: specialty sheets follow a direct path through the duplex loop without being turned, while duplex sheets are turned and processed separately. This segmentation allows each sheet type to be handled according to its specific requirements, preventing the need to empty the duplex loop and maintaining system productivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a logic module as an intermediary that determines sheet types and controls turn station operations. This intermediary ensures that only duplex sheets are turned at the first turn station, while specialty sheets pass through directly, preventing unnecessary loop emptying and maintaining continuous processing.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If all sheets are turned at the first turn station, then duplex sheets can be printed on both sides, but specialty sheets with unexchangeable edges cannot maintain their orientation

Engineering Contradiction:
Improveduplex printing capabilityVSAvoidorientation consistency of specialty sheets
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by treating different sheet types differently at the turn station. Duplex sheets are turned to enable two-sided printing, while specialty sheets with unexchangeable edges pass through without turning to maintain their predetermined edge orientation. This localized differentiation ensures each sheet type receives the appropriate handling.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The turn station operates dynamically based on sheet type detection. The logic module determines whether to activate the turn station for each sheet, allowing the system to adapt its behavior from static (always turn) to dynamic (turn only when necessary), thereby accommodating both duplex and specialty sheet requirements.

Inventive Principle:
Principle #15Dynamics

3Speed

If the duplex loop is used for interweaving sheets, then print speed increases, but the complexity of managing sheet orientation and turn stations increases

Engineering Contradiction:
Improveprint speedVSAvoidsheet handling control complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The system employs self-service mechanisms where the logic module automatically detects sheet types and controls turn station activation without manual intervention. This automation maintains the high-speed interweaving capability of the duplex loop while managing the complexity through intelligent control rather than mechanical complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The duplex loop serves multiple functions: it processes both duplex and specialty sheets, enables high-speed printing through interweaving, and maintains sheet orientation through selective turning. This multi-functionality achieves high print speed without proportionally increasing system complexity.

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

Data Source

PatentEP3248796B1Duplex printing system for cut sheets and a method therefore
Publication Date: 2019.04.03 OCE HLDG BV
  • EP3248796B1 patent drawingFigure 1
  • EP3248796B1 patent drawingFigure 2
  • EP3248796B1 patent drawingFigure 3

AI summary

The invention relates to a printing system (1) for cut sheets. The printing system comprises a control unit (37) for controlling the printing of image data on a plurality of sheets which comprise at least one speciality sheet intended to be one-sided printed and at least one duplex sheet intended to be two-sided printed. The control unit schedules the plurality of sheets in a printing order. A paper path of the printing system comprises a duplex printing loop (32, 33, 34, 35), a first turn station (35A) arranged in the duplex printing loop for turning a sheet of the plurality if both sides of the sheet are scheduled to be printed in two passes along a print engine (31) arranged in the duplex printing loop and configured to dispose marking material on the sheets according to the image data, in two passes, one side per pass, and a second turn station (38) arranged in an output section for turning the sheet before laying the sheet off in an output holder (52, 55) of the output section (5). Speciality sheets and simplex sheets in a duplex print job are treated in a special way to avoid productivity loss.