Thermal Printer Cutting Unit Independent Rack Phases
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing thermal printer designs face limitations in optimizing the design of the drive mechanism and return mechanism due to their synchronized operation, leading to potential paper jams and restricted freedom in design.
Innovation Solution
The thermal printer incorporates a printing unit with a drive mechanism and return mechanism where the drive rack and return rack have different phases, allowing independent design and operation, and an operation lever that pivots to unlock the platen unit, enabling the movable blade to be moved between a standby and cutting position while addressing paper jams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drive rack and return rack are synchronized (same phase), then the pinion gears of drive mechanism and return mechanism are driven with the same phase, but this limits the degree of freedom in designing each mechanism independently and causes paper jams
Solution Approach 1:
The patent divides the originally synchronized drive rack and return rack into two independent racks with different phases. The drive rack controls the movable blade cutting motion while the return rack independently controls the blade return motion. This segmentation allows each mechanism to be optimized separately, preventing paper jams while maintaining design freedom.
Solution Approach 2:
The patent introduces asymmetric phase relationships between the drive rack and return rack. Instead of synchronized operation, the return rack is designed with a different phase so that the pinion gear of the return mechanism engages with the return rack at a different timing than the drive pinion gear engages with the drive rack. This asymmetric design eliminates the paper jam issue caused by synchronized operation.
2Productivity
If the movable blade is moved to the cutting position to cut paper, then cutting function is achieved, but paper jam may occur causing the movable blade to stop at the climbing position
Solution Approach 1:
The patent designs the return mechanism to engage and prepare for operation before the cutting action is complete. The return pinion gear is positioned to engage with the return rack in advance, so that when paper jam occurs and the movable blade stops at the climbing position, the return mechanism is already ready to immediately return the blade without requiring additional user intervention.
Solution Approach 2:
The patent enables the system to automatically handle paper jams through the return mechanism. When the movable blade stops at the climbing position due to paper jam, the return mechanism automatically activates to return the blade to the standby position, allowing the system to service itself without external intervention.
3Device complexity
If the drive mechanism and return mechanism are synchronized, then the pinion gears are driven with the same phase, but this restricts optimum design for each mechanism
Solution Approach 1:
The patent segments the control systems into independent drive and return mechanisms with separate rack and pinion gear arrangements. The drive rack and return rack are positioned at different locations and operate with different phases, allowing each mechanism to be independently optimized for its specific function without compromise.
Solution Approach 2:
The patent introduces dynamic independence between the drive and return mechanisms. The phase difference between the drive rack and return rack allows each mechanism to operate dynamically according to its own requirements, enabling optimum design for cutting speed, force, and return motion characteristics.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A printing unit (4) includes: a head unit (5) including a thermal head (25) configured to perform printing on a recording sheet (P); a platen unit (6) which is detachably combined with the head unit (5), and includes a platen roller (45) configured to convey the recording sheet (P); a fixed blade (46) provided on one of the head unit (5) and the platen unit (6); and a movable blade (26) provided on another one of the head unit (5) and the platen unit (6) so as to be movable relative to the fixed blade (46), wherein the another one of the head unit (5) and the platen unit (6) includes: a rack member (300) coupled to the movable blade (26) so as to be movable integrally with the movable blade (26); a drive mechanism (27) which includes a drive pinion (78) allowed to mesh with the rack member (300), and is configured to move the movable blade (26) between a standby position at which the movable blade (26) is away from the fixed blade (46) and a cutting position at which the movable blade (26) climbs over the fixed blade (46); and a return mechanism (29) which includes a return pinion (131) allowed to mesh with the rack member (300), and is configured to move the movable blade (26) from the cutting position to the standby position side under a state in which the movable blade (26) is stopped at the cutting position, wherein the rack member (300) includes: a drive rack (71) including a plurality of drive rack teeth (71a) allowed to mesh with the drive pinion (78); and a return rack (130) which is formed independently of the drive rack (71), and includes a plurality of return rack teeth (130a) allowed to mesh with the return pinion (131).