Writing instrument

• US 5,217,313 A
• Filed: 04/30/1991
• Issued: 06/08/1993
• Est. Priority Date: 09/29/1989
• Status: Expired due to Term

• Current Assignee: Pentel Kabushiki Kaisha
• Original Assignee: Pentel Kabushiki Kaisha
• Inventors: Sakai, Kazuo, Suzuki, Kazunori, Kawasaki, Masayuki, Wada, Yoshihiro, Tamura, Takashi, Nagahama, Masamitsu, Enuma, Koichi
• Primary Examiner(s): DeMille, Danton D.
• Application Number:
  US07/678,322
• Time in Patent Office: 770 Days
• Field of Search: 401/198, 401/131, 401/48, 401/225, 401/227, 401/228, 401/229, 401/251, 401/243, 401/192, 401/205, 401/206, 401/219, 401/199, 401/202, 401/223, 401/258, 346/140 R, 346/140 A
• US Class Current: 401/48
• CPC Class Codes: B43K 23/08 Protecting means, e.g. caps
• CPC Class Codes: B43K 7/005 Pen barrels
• CPC Class Codes: B43K 8/00 Pens with writing-points other than nibs or balls brushes with reservoir for supplying substances A46B11/00
• CPC Class Codes: B43K 8/003 Pen barrels
• CPC Class Codes: B43L 13/024 Drawing heads therefor

Abstract

This invention relates to a writing instrument wherein a temporary ink storage member made of a synthetic resin injection molded article is sandwiched between a pen tip and an ink tank. In the present invention, a flange portion for fitting to a predetermined apparatus, which is positioned around an outer peripheral portion of the temporary ink storage member, is formed integrally with a shaft made of a synthetic resin injection molded article. In embodiments of the invention, the temporary ink storage member is made flexible, the shaft is made of a material which is softer than that of the tip holder, and the tip holder is used as a writing thickness display member. The temporary ink storage member can be used as an ink color display member and a cap is used as an application display member. In other embodiment, the cap can be fitted selectively in accordance with types of writing instruments.

Claims

1. A writing instrument for a plotter, comprising:

a hollow shaft of a synthetic resin and having a longitudinal axis;

a pen tip at a forward end of said shaft and concentric with said longitudinal axis and an ink tank at a rear end portion of said shaft;

an injection molded temporary ink storage member made of a synthetic resin and housed in said shaft between said pen tip and said ink tank said temporary ink storage member having a size for leaving a clearance between the outer periphery of said ink storage member and the inner surface of said shaft and which clearance becomes progressively greater toward the forward end of said shaft, and wherein the inner surface of said shaft has a ring-like recess therien and said clearance being greater at said recess portion than at portions forward of and toward the rear end of said shaft from said recess portion; and

a flange portion integral with said shaft and positioned around the outer peripheral portion of said shaft at a position corresponding to said temporary ink storage member within said shaft, said flange portion extending radially outwardly from the otuermost peripheral portion of said shaft and having two spaced radial surfaces for being engaged by the plotter for mounting said writing instrument on the plotter, said surfaces having a radial dimension and being spaced for being firmly engaged between and held fixedly by mounting pawls on the plotter.

2. A writing instrument as claimed in claim 1 in which said recess portion in the inner surface of said shaft is positioned at the said flange portion.

3. A writing instrument for a plotter, comprising:

a hollow shaft of a synthetic resin and having a longitudinal axis;

a pen tip holder injection molded of a synthetic resin and fitted into and fixed to a forward end of said shaft said forward end of said shaft having a front fixing portion being a press fit portion for gripping said pen tip holder with a relatively great gripping force and a rear fixing portion being concavo-convex fixing portion in engagement with said pen tip holder for gripping said pen tip holder with a relatively small gripping force and having mounted therein a pen tip projecting forward thereform along said longitudinal axis, and an ink tank at a rear end portion of said shaft;

an injection molded temporary ink storage member made of a synthetic resin and housed in said shaft between said pen tip and said ink tank; and

a flange portion integral with said shaft and positioned around the outer peripheral portion of said shaft at a position corresponding to said temporary ink storage member within said shaft, said flange portion extending radially outwardly from the outermost peripheral portion of said shaft and having two spaced radial surfaces for being engaged by the plotter for mounting said writing instrument on the plotter, said surfaces having a radial dimension and being spaced for being firmly engaged between and held fixedly by mounting pawls on the plotter;

said synthetic resin of said shaft being softer than said synthetic resin of said pen tip holder.

4. A writing instrument as claimed in claim 3 wherien said shaft has an outer diameter at said press fit portion less than the outer diameter of the remainder of said shaft.