Secondary Transfer Nip Support Layout for Uniform Image Transfer

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Solution Overview

Problem

Existing image forming apparatuses experience uneven pressure at the secondary transfer nip due to shifts in the position of the support for the secondary transfer device, leading to variations in deformation and potential faulty image transfer.

Innovation Solution

The image forming apparatus incorporates support shafts that support the intermediate transfer device on an identical axis at both lateral ends perpendicular to the recording medium conveyance direction, stabilizing the secondary transfer device and maintaining consistent pressure at the secondary transfer nip.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the support position for the secondary transfer device is shifted between lateral ends, then the secondary transfer device can be installed, but uneven pressure occurs at the secondary transfer nip

Engineering Contradiction:
Improveinstallation flexibilityVSAvoidpressure uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The support function is segmented into multiple support shafts (first support shaft and second support shaft) positioned at different lateral ends of the secondary transfer device. Each support shaft independently supports one lateral end, distributing the support function across multiple locations to maintain pressure uniformity while allowing installation flexibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple support shafts are merged into a coordinated support system where the first support shaft and second support shaft work together to simultaneously support both lateral ends of the secondary transfer device. This combined support system ensures uniform pressure distribution across the secondary transfer nip.

Inventive Principle:
Principle #5Merging (Combining)

2Stability of the object's composition

If biasing members are used to form the secondary transfer nip, then the secondary transfer device is held in position, but variation in deformation occurs due to shifted support position

Engineering Contradiction:
Improvedevice positioningVSAvoiddeformation consistency
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

Support shafts are specifically positioned at lateral ends of the secondary transfer device where support is most needed. This localized support arrangement ensures that each lateral end receives appropriate support, maintaining consistent deformation characteristics of the secondary transfer device while preserving positioning stability.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If the support position is not fixed on an identical axis, then installation is simplified, but uneven pressure and operational instability occur

Engineering Contradiction:
Improveinstallation simplicityVSAvoidoperational stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The first support shaft and second support shaft are positioned on an identical axis, creating a symmetric and balanced support configuration. This equipotential arrangement ensures that both lateral ends of the secondary transfer device receive equal support, eliminating uneven pressure and ensuring operational stability while maintaining installation simplicity.

Inventive Principle:
Principle #12Equipotentiality

Data Source

PatentEP4321935B1Image forming apparatus
Publication Date: 2026.04.01 RICOH CO LTD
  • EP4321935B1 patent drawingFigure 1
  • EP4321935B1 patent drawingFigure 2~3
  • EP4321935B1 patent drawingFigure 4~5

AI summary

An image forming apparatus (100) includes an intermediate transfer device (7) that forms a primary transfer nip (PN) between a photoconductor (2) and the intermediate transfer device (7) and primarily transfers an image from the photoconductor (2) onto the intermediate transfer device (7) at the primary transfer nip (PN). A secondary transfer device (8) forms a secondary transfer nip (N) between the intermediate transfer device (7) and the secondary transfer device (8). The secondary transfer device (8) secondarily transfers the image from the intermediate transfer device (7) onto a recording medium at the secondary transfer nip (N). At least one support shaft (74) supports the intermediate transfer device (7). The at least one support shaft (74) supports, on an identical axis, one lateral end and another lateral end of the secondary transfer device (8) in a width direction of the recording medium.