Platen Roller Nip Load Stabilization via Gear Urging
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Solution Overview
Problem
Conventional printing devices experience variations in nip load of the platen roller due to different resistances from various types of tapes, leading to instability in the printing process.
Innovation Solution
The printing device incorporates a platen gear urged toward the rotational axis of a transmission gear, along with a roller urging portion that stabilizes the nip load by balancing forces and providing an alignment mechanism for the platen roller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional alignment mechanism is used that transmits only torque, then the platen roller can be aligned, but the nip load varies with tape type due to varying conveyance torque
Solution Approach 1:
The alignment mechanism is segmented into two functional parts: a torque transmission function (for alignment) and a reaction force suppression function (for nip load stability). The platen gear is separated from the alignment mechanism and positioned to receive urging force independently, allowing it to suppress reaction forces without interfering with the torque-only alignment transmission.
Solution Approach 2:
The platen gear acts as an intermediary element between the platen roller and the output gear. By positioning the platen gear to mesh with the output gear and urging it toward the transmission gear's rotational axis, the mechanism mediates the reaction forces generated during tape conveyance, preventing them from affecting the nip load while allowing alignment to proceed through the sleeve's torque transmission.
2Adaptability or versatility
If the platen gear is allowed to move freely to accommodate varying conveyance torque, then different tape types can be used, but the reaction force on the platen gear varies causing nip load instability
Solution Approach 1:
The platen gear is preliminarily urged toward the rotational axis of the transmission gear before the printing operation begins. This preliminary urging force counteracts the reaction forces that will be generated during tape conveyance, preventing nip load variation even when different tape types with varying conveyance torque are used. The urging mechanism is pre-configured to provide this counterbalancing force.
3Reliability
If the platen gear is urged toward the rotational axis of the transmission gear, then reaction force variations are suppressed and nip load is stabilized, but the device complexity increases
Solution Approach 1:
The alignment mechanism is merged with the gear transmission system. The platen gear serves dual purposes: it transmits torque for alignment (meshing with the output gear) and suppresses reaction forces (through the urging mechanism toward the rotational axis). This merging eliminates the need for separate alignment and reaction force suppression mechanisms, reducing overall device complexity while achieving both functions.
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 effectively suppresses variations in reaction force on the platen gear, resulting in a stable nip load for the platen roller, ensuring consistent printing performance across different types of tapes.
Implementation Method 1
a roller urging portion configured to urge the roller sleeve toward the print head
Implementation Method 2
The platen gear is configured to be urged toward a transmission-gear rotational axis of the transmission gear
Implementation Method 3
a platen roller configured to face the print head... the platen roller is applied with an urging force that is balanced by a nip load generated by the platen roller
Data Source
AI summary
A printing device includes: a cassette accommodation portion; a print head; a platen roller; a platen holder; a platen gear; and a roller urging portion. The platen gear is configured to mesh with a transmission gear to receive a drive force therefrom. The platen gear is urged toward a rotational axis of the transmission gear. The platen roller includes: a platen shaft; a roller sleeve; and a roller body. The platen shaft extends through the roller sleeve in an axial direction thereof. The roller sleeve has an axial center portion connected to the platen shaft such that a torque can be transmitted from the platen shaft to the roller sleeve. The platen gear is fixed to the platen shaft and is positioned outside the roller sleeve in the axial direction. The roller urging portion is configured to urge the roller sleeve toward the print head.