Image Forming Apparatus Lock Mechanism for Document Cover Stability
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Solution Overview
Problem
The existing image forming apparatuses face issues with the document cover tipping backward due to weight imbalance, leading to potential instability and defects in document feeding and scanning, particularly when an automatic document feeder (ADF) is used, causing the document cover to be positioned differently each time it is closed, resulting in tilted scanned images.
Innovation Solution
An image forming apparatus with a lock mechanism that includes a positioning column and recess system, where the positioning column fits into a recess on the document cover, and an actuator disengages a movable hook from a fixed hook, allowing the second casing to pivot reliably while maintaining the document cover's position, preventing the apparatus from tipping backward and ensuring accurate document feeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If clearances are provided for the hinge to enable the document cover to readily open and close, then the ease of operation is improved, but the document cover is closed at different positions relative to the second casing every time, causing the document cover to appear loose and leading to document feeding and scanning defects
Solution Approach 1:
A positioning column with a positioning protrusion and a corresponding positioning recess are introduced as intermediary elements between the document cover and the second casing. The positioning protrusion fits into the positioning recess to precisely locate the document cover relative to the second casing, eliminating the positioning inconsistency caused by hinge clearances while maintaining easy operation
Solution Approach 2:
The hinge clearance parameters are optimized and controlled within specific tolerances. The positioning column and recess are designed with precise dimensional parameters that compensate for the hinge clearance, ensuring that the document cover is positioned consistently at the same location relative to the second casing despite the inherent hinge play
2Adaptability or versatility
If the document cover includes an automatic document feeder (ADF), then the functionality is improved, but the document cover becomes relatively heavy in weight, making the image forming apparatus more likely to tip backward when the document cover is open
Solution Approach 1:
A lock mechanism is implemented that engages a locking protrusion on the first casing with a locking recess on the second casing when the document cover is in the open position. This locking mechanism provides a counterbalancing force to prevent the image forming apparatus from tipping backward due to the weight of the heavy document cover with ADF, while not interfering with the normal operation when the document cover is closed
3Manufacturing precision
If a positioning mechanism having a column and a recess is provided to properly position the document cover relative to the second casing, then the positioning precision is improved, but the sizes of the second casing and the document cover increase
Solution Approach 1:
The positioning column is designed to be received within a receiving space formed in the second casing, and the positioning recess is integrated into the document cover structure. This nested arrangement allows the positioning mechanism to be compact and space-efficient, providing precise positioning without significantly increasing the overall size of the second casing or document cover
Data Source
AI summary
An image forming apparatus includes a first casing, a pivotable second casing, a pivotable document cover, and a lock mechanism including a movable hook and a fixed hook. The second casing has a document support surface. When the second casing is at a first position in which the second casing covers an upper surface of the first casing, and the document cover is at a fourth position in which the document cover reveals the document support surface, the movable hook is engaged with the fixed hook. When the second casing is at the first position, and the document cover is at a third position in which the document cover covers the document support surface, the movable hook is disengaged from the fixed hook.