Duplex Printing Color Transfer Roll Engagement Control

Solution Overview

Problem

Existing electrophotographic imaging devices face challenges in maintaining print quality during transitions between black-only and color printing due to the need for large inter-page gaps, which is not feasible in duplex printing systems where two media sheets are handled simultaneously, leading to excessive toner churning and potential collisions.

Innovation Solution

The implementation of a method that controls the engagement and disengagement of color transfer rolls and photoconductive drums to manage the transfer of toned images, allowing for efficient transitions between black-only and color printing by creating specific delay gaps and using a retraction mechanism to prevent image disturbance, while maintaining duplex printing functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a large inter-page gap is introduced to allow transition between black-only and color printing, then print quality is maintained, but productivity is reduced due to excessive delays

Engineering Contradiction:

Improveprint qualityVSAvoidprinting speed

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The media path is divided into two separate paths: a simplex media path for black-only images and a duplex media path for color images. This segmentation allows independent operation of each path, enabling the simplex path to maintain large inter-page gaps for quality transitions while the duplex path continues processing without interruption, thus resolving the contradiction between print quality and productivity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system transitions from a single-media-path approach to a multi-dimensional media handling system with separate simplex and duplex paths. By adding this dimensional separation, the system can simultaneously optimize for both print quality (in simplex path) and productivity (in duplex path) without compromise.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If the media path is emptied to allow transition between black-only and color printing, then print quality is maintained, but loss of time increases due to excessive churning

Engineering Contradiction:

Improveprint qualityVSAvoidtransition time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The media path is divided into two separate paths: a simplex media path for black-only images and a duplex media path for color images. This segmentation allows independent operation of each path, enabling the simplex path to maintain large inter-page gaps for quality transitions while the duplex path continues processing without interruption, thus resolving the contradiction between print quality and productivity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system prepares for transitions by maintaining separate dedicated paths, so when a transition is needed, the simplex path can independently manage its media without affecting the duplex path. This preliminary organization of separate paths eliminates the need to empty the entire media path, reducing transition time and avoiding excessive toner churning.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If color transfer rolls are moved before the previous image is transferred, then transition between black-only and color printing is enabled, but print quality deteriorates due to image disturbance

Engineering Contradiction:

Improvetransition capabilityVSAvoidimage quality

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The media path is divided into two separate paths: a simplex media path for black-only images and a duplex media path for color images. This segmentation allows independent operation of each path, enabling the simplex path to maintain large inter-page gaps for quality transitions while the duplex path continues processing without interruption, thus resolving the contradiction between print quality and productivity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The separate simplex and duplex media paths act as intermediaries that isolate the black-only and color printing processes. This intermediary separation allows the color transfer rolls to be moved and repositioned in the duplex path without disturbing images being processed in the simplex path, enabling smooth transitions while maintaining image quality.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution ensures efficient and high-quality printing by minimizing print quality defects and toner churning, enabling seamless transitions between black-only and color printing modes even in duplex operations, thereby enhancing the overall printing process.

Implementation Method 1

Image formation for each of the four colors includes moving toner from a reservoir to an imaging unit where toned images, black or color are formed on photoconductive (PC) drums prior to transfer directly to a media sheet or to an intermediate transfer member (ITM) belt for subsequent transfer to a media sheet

Methodology Applied

Scientific EffectElectrostatic charge transfer: Electrostatics

Data Source

PatentUS10082757B1Method to control transfer of black and color toned images during combined simplex duplex printing

Publication Date: 2018.09.25 LEXMARK INTERNATIONAL INC

AI summary

A method for controlling transfer of black and color toned images during combined simplex and duplex printing in an electrophotographic imaging device having either a plurality of movable color photoconductive drums or a plurality of moveable color transfer rolls.