Sheet Curl Correction Using Blower Arrays in Image Formers
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Solution Overview
Problem
In image forming apparatuses, existing methods struggle to effectively correct curls in discharged sheets, particularly at the side portions, due to the central placement of fans which limits air distribution across the sheet's width, leading to misalignment during stacking.
Innovation Solution
The apparatus incorporates a discharge port, a sheet stacking plate with sliding cursors, blowers, and a controller to direct air to the sheet's side corners, ensuring proper curl correction by pressing the curled edges downward.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fans are disposed in the center portion of the sheet in the width direction, then the structure is simple, but it is difficult to send air over all area of the sheet and the curl of the side portions cannot be corrected suitably
Solution Approach 1:
The single central fan is segmented into multiple fans (first fan and second fan) positioned at different locations. The first fan is disposed at a position wider in the width direction than the discharge means, and the second fan is disposed at a position narrower in the width direction than the discharge means. This segmentation allows air to be blown to different regions of the sheet simultaneously, enabling comprehensive curl correction across the entire sheet width while maintaining structural simplicity.
2Manufacturing precision
If stiffness is imparted to the sheet through the discharge device, then misalignment is prevented, but the correction effect is lost after the sheet passes through the discharge device
Solution Approach 1:
The fans blow air to the sheet immediately after discharge from the discharge means, before the sheet fully settles on the sheet stacking plate. This preliminary action addresses the curl at the timing when it first appears, preventing misalignment from occurring in the first place rather than attempting to correct it after the sheet has already misaligned on the stacking plate.
3Manufacturing precision
If a convex shape is formed on the discharge tray, then the sheet is corrected after discharge, but the sheet may be deformed according to the convex shape
Solution Approach 1:
Instead of using mechanical contact correction methods like convex shapes on the discharge tray, the invention employs pneumatic correction using fans that blow air to the sheet. This non-contact method corrects the sheet's curl through air pressure without physically deforming the sheet, thereby maintaining sheet shape integrity while achieving the desired correction effect.
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 configuration ensures reliable air distribution to the sheet's side edges, effectively correcting curls and maintaining proper sheet alignment, even during continuous discharge.
Implementation Method 1
The pair of blowers is provided in the pair of cursors so as to blow air to both corners on an upstream side in the discharge direction of the sheet which is discharged through the discharge port, from above
Data Source
AI summary
An image forming apparatus (1) includes a discharge port (25), a sheet stacking plate (41), a pair of cursors (43), a cursor driver (95), a pair of blowers (83) and a controller (37). Through the discharge port (25), a sheet formed an image is discharged. On the sheet stacking plate (41), the sheet discharged through the discharge port (25) is stacked. The pair of cursors (43) is supported on the sheet stacking plate (41) in a slidable manner in width directions perpendicular to a discharge direction of the sheet and comes into contact with both side edges of the sheet. The cursor driver (95) drives the pair of cursors (43). The pair of blowers (83) is provided in the pair of cursors (43) so as to blow air to both corners on an upstream side in the discharge direction of the sheet which is discharged through the discharge port (25), from above. The controller (37) controls the cursor driver (95) and the pair of blowers (83).