Transfer Nip Spacing Control for Mixed Media Thickness

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Solution Overview

Problem

Image forming apparatuses face challenges in reducing shock jitter during continuous printing, especially when handling recording media of varying thicknesses, as existing solutions either fail to adjust the space between the intermediate transfer belt and the secondary transfer roller quickly enough or compromise productivity by increasing the sheet interval area.

Innovation Solution

An image forming apparatus with a contact-and-separation device controlled by an eccentric cam and a thickness detector adjusts the space between the intermediate transfer belt and the secondary transfer roller based on the thickness of successive sheets, ensuring minimal impact and maintaining productivity by coordinating the cam positions to match the thickness group of the incoming sheet before it enters the transfer nip.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the intermediate transfer belt and secondary transfer roller are completely separated to eliminate transfer pressure, then shock jitter is reduced when recording medium enters and exits, but impact is generated when they come in contact again due to spring force

Engineering Contradiction:
Improveshock jitterVSAvoidimpact
Core Design Contradiction:
Object-affected harmful factorsVSForce

Solution Approach 1:

The control unit performs preliminary action by detecting the thickness of the recording medium in advance and controlling the contact-and-separation device to set the space between the intermediate transfer belt and secondary transfer roller before the recording medium enters the secondary transfer nip. This ensures the appropriate space is already in place to minimize both shock jitter and impact.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the space between the intermediate transfer belt and secondary transfer roller based on the detected thickness of the recording medium. The contact-and-separation device changes the positional relationship between these components from a contacted state to a separated state with a predetermined space, making the system adaptive to different medium thicknesses.

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If the space between intermediate transfer belt and secondary transfer roller is increased to reduce impact, then shock jitter is reduced, but transfer pressure is insufficient causing transfer failure

Engineering Contradiction:
Improveshock jitterVSAvoidtransfer failure
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The system dynamically adjusts the space between the intermediate transfer belt and secondary transfer roller based on the detected thickness of the recording medium. The contact-and-separation device changes the positional relationship between these components from a contacted state to a separated state with a predetermined space, making the system adaptive to different medium thicknesses.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control unit changes the physical parameter (space distance) between the intermediate transfer belt and secondary transfer roller based on the thickness parameter of the recording medium. This parameter adjustment ensures adequate transfer pressure while minimizing shock jitter for different medium types.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If the contact-and-separation device adjusts the space between intermediate transfer belt and secondary transfer roller according to recording medium thickness, then shock jitter is reduced, but device complexity increases

Engineering Contradiction:
Improveshock jitterVSAvoiddevice complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The control unit acts as an intermediary that receives thickness information from the sheet thickness detection device and controls the contact-and-separation device accordingly. This intermediary coordination integrates the detection and separation functions without requiring direct complex interaction between the detection and separation mechanisms.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Object-affected harmful factors

If the sheet interval area is increased to allow space adjustment between sheets of different thickness, then shock jitter is reduced, but productivity decreases

Engineering Contradiction:
Improveshock jitterVSAvoidproductivity
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The control unit performs preliminary action by detecting the thickness of the recording medium in advance and controlling the contact-and-separation device to set the space between the intermediate transfer belt and secondary transfer roller before the recording medium enters the secondary transfer nip. This ensures the appropriate space is already in place to minimize both shock jitter and impact.

Inventive Principle:
Principle #10Preliminary action

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 effectively reduces shock jitter by precisely adjusting the space between the transfer components according to the thickness of incoming sheets, maintaining high productivity even with fast processing speeds and varying media thicknesses.

Implementation Method 1

a sheet thickness detection device that detects thickness of the recording medium P

Methodology Applied
Scientific EffectThickness detection:

Implementation Method 2

a contact-and-separation device that moves an intermediate transfer belt and a secondary transfer roller to contact and separate from each other

Methodology Applied
Scientific EffectMechanical movement:

Implementation Method 3

the secondary transfer roller is released by the eccentric cam and is pushed against the intermediate transfer belt by a spring

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 4

Before the recording medium enters the secondary transfer nip, an eccentric cam of the contact-and-separation device separates the secondary transfer roller from the intermediate transfer belt

Methodology Applied
Scientific EffectEccentric mechanism: Eccentric

Data Source

PatentEP2950155B1Image forming apparatus
Publication Date: 2019.10.02 RICOH CO LTD
  • EP2950155B1 patent drawingFigure 1
  • EP2950155B1 patent drawingFigure 2~3
  • EP2950155B1 patent drawingFigure 4~5

AI summary

An image forming apparatus (1) includes an image bearer (131), a nip forming device (135), a contact-and-separation device (30), a thickness information retrieving device (160), and a controller (200). The contact-and-separation device (30) moves the image bearer (131) and the nip forming device (135) to contact and separate from each other. The controller (200) controls the contact-and-separation device (30) based on information on a thickness of a recording medium obtained by the thickness information retrieving device (160) such that in a case in which a thickness of a preceding recording medium and a thickness of a successive recording medium are different in continuous printing in which a plurality of recording media is printed out continuously, the contact-and-separation device (30) adjusts a space between the image bearer (131) and the nip forming device when the preceding recording medium exits the transfer nip to a preset size corresponding to the thickness of the successive recording medium that enters the transfer nip.