Knock-type writing instrument

The knock-type writing instrument addresses impact-induced deformation and ink bubble issues by employing a specialized design with angled guide protrusions and grooves, ensuring smooth operation and reduced discomfort.

JP2025113226APending Publication Date: 2025-08-01MITSUBISHI PENCIL CO LTD
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Patent Information

Application Number
JP2025008591
Authority / Receiving Office
JP · JP
Patent Type
Applications
Current Assignee / Owner
Priority Date
2024-01-22
Filing Date
2025-01-21
Publication Date
2025-08-01

AI Technical Summary

Technical Problem

Existing knock-type writing instruments experience issues with impact-induced deformation of the knock button protrusions, leading to increased length and air bubble generation in the refill ink, along with discomfort during use due to discontinuous operations.

Method used

The design incorporates a shaft cylinder, refill, knock spring, cam portion, pressing rod, rotor, knock button, guide protrusions, and guide grooves with specific angle relationships to minimize impact and deformation, ensuring continuous operation and reduced ink bubble formation.

Benefits of technology

The solution effectively suppresses knock button deformation, reduces impact sound, and prevents ink bubble generation, maintaining a consistent operating feel and reducing discomfort during use.

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Abstract

To prevent the mountain-shaped protrusion of the knock button from being crushed and deformed, mitigating the impact of the knock release stop, suppressing the generation of ink bubbles in the refill, and reducing impact noise.SOLUTION: Provided is a knock-type writing instrument including: a plurality of guide protrusions protruding from the outer periphery near the tip of a knock button; mountain-shaped protrusions formed at the rear ends of the guide protrusions and protruding rearward in an inverted V shape; guide grooves formed on the inner surface near the rear end of a barrel as longitudinal grooves in which the guide protrusions can slide longitudinally with the guide protrusions housed; and a mountain-shaped inner wall formed at the rear end of the guide groove and recessed rearward in an inverted V shape. When the angle of the mountain-shaped inner wall is α and the angle of the mountain-shaped protrusion is β, α<β.SELECTED DRAWING: Figure 8A
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Citation Information

Patent Citations

  • JP1973037222A

  • JP1973048730U

  • Knock-type writing utensil with impact buffer

    JP2009045825A

  • Knock-type writing instrument

    JP2023020632A

  • Knock type writing instrument

    JP2023085968A