Portable Printer Frame Rib Structure for Drop-Impact Durability
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Solution Overview
Problem
Existing printing units in portable terminals are prone to damage from drop impacts due to the inertia of the motor, which can cause the frame to break.
Innovation Solution
The printing unit incorporates a frame design with a motor support portion, a base portion, mounting portions, a protruding portion, and a rib that connects the protruding portion to the base portion, along with a guide surface inclined to guide the recording sheet towards the thermal head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the motor is mounted on the frame to drive the platen roller, then the printing unit can perform printing functions, but the frame may be broken when the portable terminal is dropped due to inertia of the motor
Solution Approach 1:
The frame is divided into a motor support portion and a base portion that are separable through the protruding portion. This segmentation allows the motor support portion to be positioned away from the center of gravity, reducing the moment arm and thereby minimizing the impact force transmitted to the base portion during drop events.
Solution Approach 2:
The protruding portion extends in a direction away from the center of gravity of the printing unit. By positioning the motor support portion in this extended direction, the design utilizes spatial dimensionality to create a longer moment arm, which reduces the torque generated during impact and protects the base portion from breakage.
2Reliability
If the motor support portion is positioned away from the center of gravity to reduce impact, then durability improves, but the structure becomes more complex
Solution Approach 1:
The motor support portion is merged with the frame structure through the protruding portion, creating an integrated design. This merging allows the motor support portion to be positioned away from the center of gravity while maintaining structural coherence, avoiding the need for separate mounting brackets or additional reinforcement elements.
Solution Approach 2:
The protruding portion serves multiple functions: it acts as a structural connector between the motor support portion and base portion, provides a positioning reference for the motor, and creates the necessary moment arm for impact reduction. This multi-functionality reduces the need for additional components and simplifies the overall structure.
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 enhances the durability of the printing unit against drop impacts by distributing the load and reducing stress concentration, thereby preventing frame breakage.
Implementation Method 1
a guide surface configured to guide the recording sheet toward the thermal head
Implementation Method 2
a thermal head configured to perform printing on the recording sheet through press contact with an outer peripheral surface of the platen roller
Implementation Method 3
a motor configured to serve as a drive source of the platen roller
Data Source
AI summary
A printing unit includes: a platen roller configured to convey a recording sheet; a thermal head configured to perform printing on the recording sheet through press contact with an outer peripheral surface of the platen roller; a motor configured to serve as a drive source of the platen roller; and a frame configured to support the platen roller in a rotatable manner, wherein the frame includes: a motor support portion configured to support the motor; a base portion which is connected to the motor support portion, and extends in an axial direction of the platen roller; mounting portions which are attached to a member on which the printing unit is to be mounted; a protruding portion which protrudes from the base portion; and a rib which is provided between the motor support portion and the mounting portions, and extends so as to connect the protruding portion and the base portion to each other, wherein the base portion includes a guide surface configured to guide the recording sheet toward the thermal head, and wherein the guide surface is inclined with respect to a normal direction of a head surface of the thermal head.