Sheet-feed Device with Pivotable Guide for Glossy Paper Protection
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Solution Overview
Problem
Existing sheet-feed devices risk damaging recording surfaces, particularly glossy papers, due to the angular or pointed tips of separation protrusions, leading to image quality deterioration during the sheet separation process.
Innovation Solution
A sheet-feed device with an inclined sheet-separation plate and pivotable sheet guide members that prevent the recording sheet from contacting the separation pawls, using a second contact portion to move the sheet away from the pawls, ensuring the recording surface is not damaged.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separation protrusions with angular or pointed tips are used to separate recording sheets, then sheet separation reliability is improved, but the recording surface may be damaged leading to image quality deterioration
Solution Approach 1:
The separation protrusions are designed with rounded tips instead of angular or pointed tips. This curvature modification eliminates the harmful concentration of stress at sharp edges while maintaining the separation function, thereby preventing damage to the recording surface of glossy papers during the sheet feeding process
Solution Approach 2:
Only the tip portion of the separation protrusions is modified with rounded geometry, while the rest of the protrusion structure maintains its original shape for effective separation. This localized modification achieves the dual goal of reliable sheet separation and protection of the recording surface
2Reliability
If a sheet-feed roller presses recording sheets with large pressing force, then sheet feeding reliability is improved, but multi-feeding may occur where two or more sheets are fed simultaneously
Solution Approach 1:
The inclined sheet-separation plate is positioned to preliminarily separate sheets before they reach the sheet-feed roller. By creating separation in advance through the inclined plane, the system reduces the likelihood of multiple sheets being fed simultaneously even when the roller applies large pressing force
Solution Approach 2:
The separation protrusions on the inclined sheet-separation plate create preliminary resistance against multi-feeding by engaging with the leading edges of sheets before they enter the feeding zone. This preliminary anti-action counteracts the tendency toward multi-feeding caused by high pressing force
Data Source
AI summary
A sheet-feed device, including: a sheet accommodating portion for accommodating sheets; a sheet-feed roller which feeds one of the sheets located uppermost among the accommodated sheets; an inclined sheet-separation plate; separation pawls arranged on the sheet-separation plate for cooperating with the roller to separate the one of the sheets from the other sheets; a sheet guide member supported on the sheet-separation plate so as to pivot about an axis and including: a first contact portion located on a sheet feeding route and configured to contact the separated sheet; and a second contact portion located on one side of the axis remote from the first contact portion and configured to protrude from the sheet-separation plate so as to contact the separated sheet owing to a pivotal movement of the guide member by a contact of the separated sheet with the first contact portion, whereby the separated sheet is moved away from the separation pawls.