Image Forming Apparatus Double-Side Transfer Voltage Adjustment

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Solution Overview

Problem

Existing image forming apparatuses face challenges in accurately adjusting the transfer voltage during double-side printing, especially when using small-size recording materials, due to overlapping patches and set-off issues.

Innovation Solution

The image forming apparatus includes a controller that executes an operation in a double-side mode and an output mode, where a chart with test images is outputted to adjust the transfer voltage. The controller selectively performs operations to fix test images on one side of the recording material and then transfer them to the other side, allowing for accurate adjustment of the transfer voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If double-side printing is performed with patches on both sides for transfer voltage adjustment, then the adjustment can be performed for double-side printing conditions, but the patches overlap on front and back sides causing inaccurate density detection due to set-off

Engineering Contradiction:

Improveadjustment capability for double-side printingVSAvoidpatch density detection accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent divides the adjustment process into two separate operations: first forming and fixing patches on the first side, then forming and fixing patches on the second side. This segmentation prevents overlapping effects during detection by ensuring patches are fixed on separate sides before secondary transfer, thereby resolving the measurement accuracy issue while maintaining double-side printing adjustment capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary fixing of patches on the first side before forming patches on the second side. This preliminary action ensures that the first-side patches are securely fixed and will not interfere with the formation or detection of second-side patches, eliminating set-off problems during density detection

Inventive Principle:

Principle #10Preliminary action

2Area of stationary object

If small-size recording materials are used for outputting adjustment charts, then the chart output size is reduced, but the patches are liable to overlap with each other on front and back sides due to small margins

Engineering Contradiction:

Improvechart output areaVSAvoidpatch positioning accuracy

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent segments the patch formation process into distinct first-side and second-side operations with preliminary fixing. This allows efficient use of small recording material area while preventing overlap through sequential processing, thereby maintaining positioning accuracy despite limited margins

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary fixing of first-side patches before second-side patch formation. This ensures that even with small margins on compact recording materials, the patches remain properly positioned and do not overlap during the adjustment chart output process

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 enables appropriate adjustment of the transfer voltage during double-side printing, even with small-size recording materials, thereby improving the accuracy and quality of the image forming process.

Implementation Method 1

The transfer of the toner image from an image bearing member to the recording material is performed by applying a transfer voltage to a transfer member such as a transfer roller which contacts the image bearing member to form a transfer portion

Methodology Applied

Scientific EffectElectrostatic transfer: Electrostatic Induction

Implementation Method 2

a fixing device configured to fix the toner image, transferred on the recording material, on the recording material in a fixing portion

Methodology Applied

Scientific EffectThermal fixation: Heating

Data Source

PatentUS12282274B2Image forming apparatus capable of forming test images on different sides of recording materials

Publication Date: 2025.04.22 CANON KK

AI summary

An image forming apparatus includes an image bearing member, a transfer device, a voltage applying portion, a fixing device, and a controller. During execution of an operation in an output mode, the controller is capable of selectively executing: an operation in which test images formed on a first side of a first recording material are fixed and then the first recording material is outputted without forming the test images on a second side of the first recording material and then in which a second recording material is passed through the fixing device without forming the test images on a first side of the second recording material and then the test images are transferred onto a second side of the second recording material.