Image Forming Apparatus with Upstream Ion Discharge for Sheet Stacking
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Solution Overview
Problem
Existing image forming apparatuses experience uneven stacking of sheets due to re-charging during post-processing, leading to stacking shift and electrostatic issues in downstream sheet stacking devices.
Innovation Solution
Incorporation of a non-contact ion type static eliminator (discharging device) adjacent to sheet stacking devices on the upstream side in the sheet conveyance direction, which generates positive and negative ions to neutralize static charge before sheets reach the stacking devices, combined with a detachable design for easy installation between post-processing units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a non-sheet stacking device is disposed between the image forming apparatus main body and the sheet stacking device, then post-processing can be applied to the sheet, but the sheet is re-charged by peeling discharge and friction, causing high charge amount and stacking unevenness
Solution Approach 1:
The discharger is positioned upstream of the sheet stacking device to neutralize static charge on sheets before they enter the stacking device. This preliminary charge elimination prevents the sheets from acquiring high charge amounts during subsequent passage through the non-sheet stacking device and guide surfaces, thereby preventing stacking unevenness while allowing post-processing to be performed.
2Object-affected harmful factors
If a charge adjustment device is disposed immediately after the image forming section, then sheet sticking can be prevented, but stacking unevenness occurs in downstream sheet stacking devices due to cumulative residual charge
Solution Approach 1:
Instead of using a single charge adjustment device, the system employs multiple dischargers positioned at different locations: one immediately after the image forming section to prevent sheet sticking, and another upstream of the sheet stacking device to eliminate residual charge. This segmentation of the charge elimination function into separate devices allows each to address specific issues without causing cumulative charge problems.
3Manufacturing precision
If a non-contact ion type static eliminator is added to neutralize static charge, then stacking unevenness can be suppressed, but device complexity increases
Solution Approach 1:
The discharger is designed with multi-functionality: it serves both as a charge elimination device for preventing stacking unevenness and as a component that can be integrated into the existing sheet conveyance system. By positioning the discharger upstream of the sheet stacking device, it simultaneously prevents charge accumulation from multiple sources (peeling discharge, friction with guide surfaces), making it a universal solution for various electrostatic issues in the system.
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
Effectively suppresses sheet uneven stacking by maintaining residual charge levels close to zero, reducing electrostatic problems and enabling efficient sheet handling without additional hardware in the apparatus.
Implementation Method 1
a non-contact ion type static eliminator (discharging device) adjacent to sheet stacking devices on the upstream side in the sheet conveyance direction, which generates positive and negative ions to neutralize static charge
Data Source
AI summary
Disclosed is an image forming apparatus including: a non-sheet stacker which is adjacent to a downstream side in a sheet conveyance direction of an image forming apparatus main body and applies post-processing to a sheet output from the image forming apparatus main body; and a sheet stacker which is one or a plurality of sheet stackers located on a downstream side in the sheet conveyance direction of the non-sheet stacker. A discharger is disposed adjacent to an upstream side in the sheet conveyance direction of at least one of the sheet stacker.