Double-Side Transfer Voltage Adjustment via Non-Overlapping Test Charts
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Solution Overview
Problem
In double-side printing, setting the secondary transfer voltage for the second side is challenging due to variations in toner density and transfer current, often resulting in insufficient or excessive transfer, leading to image defects like roughening or white voids.
Innovation Solution
An image forming apparatus that outputs a double-side chart with non-overlapping test images on both sides, allowing the controller to set the transfer voltage based on density readings from each side, ensuring the secondary transfer voltage for the second side is appropriately higher than the preset condition to maintain optimal transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the secondary transfer voltage for the second side is set based on the double-side chart with overlapping patches, then the adjustment process can be completed, but the density detection becomes inaccurate due to interference from the first-side patches
Solution Approach 1:
The patent divides the chart into distinct first-side patches and second-side patches that do not overlap. This segmentation allows independent density detection for each side, eliminating interference between layers and enabling accurate measurement of the second-side patch density.
Solution Approach 2:
The patent extracts only the density information from the non-overlapping second-side patches for voltage adjustment decisions, excluding interference from first-side patches. This selective extraction ensures accurate density detection specifically for the second side.
2Manufacturing precision
If the secondary transfer voltage is increased to ensure sufficient transfer, then image density improves, but electric discharge occurs causing white voids and improper transfer
Solution Approach 1:
The patent uses density detection of the second-side patches as feedback to determine the appropriate secondary transfer voltage. By measuring actual transfer results and adjusting voltage accordingly, the system achieves optimal transfer without excessive voltage that would cause discharge.
Solution Approach 2:
The patent adjusts the secondary transfer voltage parameter based on detected density values and transfer conditions. By dynamically changing this parameter according to actual performance, the system maintains optimal transfer quality while avoiding harmful discharge effects.
3Object-affected harmful factors
If the secondary transfer voltage is decreased to prevent electric discharge, then white voids are reduced, but insufficient transfer occurs causing roughening and poor density
Solution Approach 1:
The patent employs feedback from density detection to determine the minimum necessary secondary transfer voltage. By monitoring transfer results and adjusting voltage to the lowest effective level, the system prevents discharge while ensuring sufficient transfer quality.
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 approach enables accurate setting of the secondary transfer voltage for the second side, preventing image defects by ensuring sufficient transfer current and maintaining image density, thus improving the quality of double-side printed images.
Implementation Method 1
a toner image is electrostatically transferred from an image bearing member onto a recording material such as paper. This transfer is carried out in many cases by applying a transfer voltage to a transfer member forming a transfer portion in contact with the image bearing member.
Implementation Method 2
a chart (adjusting chart) on which a plurality of patches (test images) is formed and outputted on a single recording material while switching the secondary transfer voltage (test voltage) for each patch is formed. This chart is read by a reading portion provided in the image forming apparatus and a density of each patch is read.
Data Source
AI summary
An image forming apparatus includes an image forming portion, a transfer portion, a power source, a reading portion, and a controller. The controller executes an output operation so that first test images do not overlap with second test images, respectively, on a first side and a second side of a recording material. On the basis of information on a second test voltage for transfer of the second test image, of the plurality of second test images, of which information on a density read by the reading portion coincides with a preset condition, the controller sets a transfer voltage for image transfer onto the second side in double side image formation so that an absolute value of the transfer voltage set for the image transfer onto the second side in double side image formation is greater than an absolute value of the second test voltage that coincides with the preset condition.