Sheet Conveyance Roller Control for Skew Alignment Without Buckling
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Solution Overview
Problem
Existing image forming apparatuses experience relative rotational speed differences between skewing rollers, leading to potential buckling and misalignment of sheets during conveyance.
Innovation Solution
A sheet conveyance apparatus with a configuration that includes a conveyance rotary member pair, a first and second skewing rotary member pair, and a control unit to manage rotational speeds and switching between nipping and non-nipping states to minimize speed differences and align sheets accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the angle of the skewing roller is increased to cause the sheet to arrive at the reference member, then the sheet can be conveyed to the reference member, but the sheet may strongly abut against the reference member and be buckled
Solution Approach 1:
The patent applies dynamics by making the skewing roller pressurization adjustable and switchable between states. The control unit dynamically adjusts the pressurization of the skewing roller based on the conveyance stage, reducing pressure when the sheet is far from the reference member to prevent buckling, and increasing pressure when the sheet is close to ensure proper contact and alignment.
Solution Approach 2:
The patent changes the parameter of skewing roller pressurization dynamically. By controlling the pressurization force to vary between different stages of sheet approach to the reference member, the system optimizes both sheet conveyance and prevents harmful buckling effects.
2Manufacturing precision
If the rotation angle direction of the skewing roller is made different from the registration roller, then the sheet can be aligned, but a relative speed difference occurs causing accuracy degradation
Solution Approach 1:
The patent changes the rotational speed parameter of the skewing roller dynamically. When the skewing roller is not in contact with the sheet (non-nipping state), its rotational speed is reduced to match the registration roller's speed, eliminating relative speed differences and ensuring conveyance accuracy while maintaining alignment functionality.
3Productivity
If pressurization of one roller is released and the sheet is conveyed by the other roller, then conveyance continues, but a relative speed difference occurs
Solution Approach 1:
The patent adjusts the rotational speed parameter of the active skewing roller to match the registration roller's speed when operating in alternating conveyance modes. This ensures that even when one roller is released, the other roller operates at a compatible speed, preventing relative speed differences and maintaining conveyance reliability.
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
The solution effectively reduces relative rotational speed differences, ensuring precise sheet alignment and conveyance, thereby improving the accuracy and reliability of image formation.
Implementation Method 1
a first skewing rotary member pair disposed downstream of the conveyance rotary member pair in the sheet conveyance direction and configured to obliquely convey the sheet toward the abutment portion
Implementation Method 2
a conveyance rotary member pair configured to nip and convey a sheet
Data Source
AI summary
A sheet conveyance apparatus includes a conveyance rotary member pair, an abutment portion, a first skewing rotary member pair, a switching unit, a driving unit, and a control unit. The switching unit switches the first skewing rotary member pair between a nipping conveyance state in which a sheet is nipped and conveyed and a non-nipping state in which nipping of the sheet is released. The control unit controls a rotational speed of the first skewing rotary member pair to be a first speed when the sheet is obliquely conveyed to the abutment portion by the first skewing rotary member pair, and controls the rotational speed of the first skewing rotary member pair to be a second speed lower than the first speed when the first skewing rotary member pair is in the non-nipping state and the conveyance rotary member pair conveys the sheet.