Printing Unit Sensor Mounting via Flexible PCB Locking
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Solution Overview
Problem
Existing printing units are bulkier due to the increased number of parts required for mounting sensors, which complicates the fixing structure and hinders downsizing efforts, particularly in portable terminals.
Innovation Solution
A printing unit design featuring a flexible printed board with a sensor mounting portion and a frame that includes locking projections and a sheet guide portion, allowing the sensor to be securely locked without additional components, thus simplifying the fixing structure and reducing the overall size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate holder member is provided to sandwich and fix the sensor between the sheet guide portion and the holder, then the sensor can be securely mounted, but the number of parts increases and the contour size of the sheet guide portion increases, leading to an increased overall size of the printing unit
Solution Approach 1:
The sensor mounting portion is integrated directly into the flexible printed board, eliminating the need for a separate holder member. The flexible printed board itself serves as both the electrical connection carrier and the sensor mounting structure, merging multiple functions into a single component that securely holds the sensor while maintaining a compact overall size.
2Ease of manufacture
If a separate holder member is provided to sandwich and fix the sensor, then the sensor can be mounted, but the sheet guide portion must surround the holder which increases the contour size and complicates the fixing structure
Solution Approach 1:
The sensor mounting portion is formed as an integrated structure on the flexible printed board, combining the mounting function with the electrical connection function. This eliminates the need for separate holder members and complex surrounding structures, simplifying the overall fixing structure while maintaining ease of manufacture.
Solution Approach 2:
The flexible printed board serves multiple functions: it provides electrical connections to the thermal head and platen roller, and it also serves as the sensor mounting platform. This multi-functionality reduces the need for separate dedicated mounting structures, simplifying the overall design.
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 design enables a more compact printing unit by eliminating the need for separate components, enhancing workability and reliability while maintaining accurate sheet detection.
Implementation Method 1
a printing unit which has hitherto been known is configured to perform printing by heating a printing surface of a recording sheet with heating elements of a thermal head
Implementation Method 2
a sensor for detecting the recording sheet conveyed along the sheet guide portion is mounted to the sheet guide portion
Data Source
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AI summary
A printing unit (6) includes: a platen roller (50) configured to convey a recording sheet (P); a thermal head (40) configured to perform printing on the recording sheet (P) through press contact with an outer peripheral surface of the platen roller (50); a sensor (80), which is arranged in such a manner as to face the platen roller (50), and is configured to detect the recording sheet (P); a flexible printed board (70) including a sensor mounting portion (76) on which the sensor (80) is mounted; and a frame (10), which is configured to support the platen roller (50) in a rotatable manner, and includes a locking projection (26) to which the sensor mounting portion (76) is to be locked.