JPH0222305Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to an ink drying prevention device for writing implements such as fountain pens, marking pens, ballpoint pens, etc., which have built-in ink cylinders containing volatile ink.

(Prior art) If this type of writing instrument is left unused for a long period of time from the manufacturer to the user's hands, and even after reaching the user's hands, the solvent in the ink will evaporate. There is a problem in that writing becomes impossible or blurred.

In particular, when the barrel is made of a synthetic resin such as polystyrene, the above problem occurs because the synthetic resin itself allows the solvent to permeate, no matter how securely the cap is fitted into the barrel.

In order to solve this problem, an attempt has been made to suppress the drying of the ink inside the writing instrument by storing a holder impregnated with a solvent in the case that houses the writing instrument and allowing the solvent to evaporate within the case. (Tokuko Sho 49-2297).

An attempt has also been made to suppress ink drying by installing a holder in a writing instrument impregnated with a solvent having a vapor pressure higher than that of the ink in the ink cylinder (Utility Model Application No. 57-201512).

On the other hand, the ink cylinder of a writing instrument has an open end so that ink can flow out smoothly. Therefore, the ink evaporates from the open end. Or, when a shock is applied to the writing instrument, ink scatters from the open end,
There was a risk that the liquid might leak into or out of the writing instrument and stain clothes, etc.

(Purpose of the invention) This invention simultaneously solves the above-mentioned problems of ink drying and scattering, and has an excellent effect of preventing ink from drying, and even if the ink scatters due to impact, the ink does not leave the writing instrument. To provide an ink drying prevention device that does not cause ink to leak and stain clothes, etc.

(Structure of the invention) This invention is a writing instrument in which a pen nib 4 is attached to the tip and an ink cylinder 5 with an open end is built into the barrel cylinder 1. Between the end of the cylinder 5 and the bottom of the barrel 1, there is a liquid having a vapor pressure higher than that of the ink 6.
A holder 7 impregnated with an anti-drying agent is sandwiched, and an air hole 51 is formed in the side surface of the end of the ink cylinder 5 to connect the space 8 in the end of the ink cylinder 5, the outer peripheral surface of the ink cylinder 5, and the shaft cylinder 1. The space 9 between the inner peripheral surfaces is communicated.

(Example) This invention will be explained in detail according to examples.

In Figure 1, 1 is the barrel, 2 is the tail plug that is tightly fitted to the end of the barrel, and 3 is the cap that is tightly fitted to the tip of the barrel, and these three parts are made of thermoplastic synthetic resin such as polystyrene. .

However, even if some of the three parts, such as the cap, are made of metal, the effect of this invention can be exerted.

Reference numeral 4 designates a pen nib configured as a ballpoint pen that guides ink by capillary action, and 5 designates an ink cylinder with the nib 4 attached to the tip and an open end, in which ink 6 is housed leaving a space 8 at the end.

The tip of the ink cylinder 5 is tightly fitted and held in a nib holder 11 which is the tip of the barrel 1, and an air hole 51 communicating with the space 8 is bored in the side surface near the end.

Reference numeral 7 denotes a holder fixedly attached to the shaft body 71, which is made of a sponge-like foam material and is impregnated with an anti-drying agent, which is a liquid whose vapor pressure is higher than that of the ink 6.

The holder 7 is fitted inside the tail plug 2 and is clamped and fixed between the tail plug 2, which forms the bottom of the barrel 1, and the end of the ink cylinder 5 via the cylinder 71.

9 is a space between the outer circumferential surface of the ink cylinder 5 and the inner circumferential surface of the shaft cylinder 1, and is communicated with the space 8 through the air hole 51.

The vapor pressure of the ink 6 of this invention is designed to be lower than the vapor pressure of the anti-drying agent, that is, the vapor pressure of the anti-drying agent is higher than the vapor pressure of the ink. As an example, the ink may include dyes or pigments, water-soluble resins,
When the anti-drying agent is composed of water and a hygroscopic agent such as ethylene glycol or glycerin, the anti-drying agent may contain water and a hygroscopic agent such as ethylene glycol or glycerin.

If the amount of moisture absorbent relative to water is large for ink and small for anti-drying agent, the vapor pressure of the ink will be lower than the vapor pressure of the anti-drying agent.

(Functions and Effects) Therefore, when this writing instrument is left alone, the water in the drying agent has a high evaporation rate and evaporates more quickly than the holder 7, but the ink 6 in the ink cylinder 5
Almost no water evaporates. Then, water vapor evaporated in space 8 (most of it evaporated from the desiccant)
Since the ink passes through the air hole 51 and fills the space 9, it is extremely rare for the moisture in the ink in the ink cylinder 5 to permeate the resin of the ink cylinder 5 and evaporate.

Furthermore, while the writing instrument is being stored, moisture in the space 9 passes through the barrel 1, which is a molded product of synthetic resin.
Most of the moisture corresponding to the moisture that permeated and volatilized evaporates from the drying inhibitor and fills the spaces 8 and 9, so that only a small amount of the ink moisture still evaporates. Furthermore, since the water in the ink begins to evaporate only after the water in the anti-drying agent has evaporated, the writing instrument can be used to write smoothly even after being stored for an extremely long period of time, and an excellent ink drying prevention effect can be obtained.

Further, even if the ink 6 in the ink cylinder 5 is scattered due to an impact applied to the writing instrument, there is no fear that it will be absorbed by the holder 7 of the drying prevention device and flow out of the writing instrument, staining clothes etc. outside the writing instrument. In addition, since it is sandwiched between the end of the ink cylinder 5 and the end of the shaft cylinder 1, the holding and fixing of the holder 7 is ensured. Since the air hole is on the side, the air hole is closed and prevents ink from flowing out improperly. It has side effects such as

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an embodiment of this invention. DESCRIPTION OF SYMBOLS 1... Shaft cylinder, 5... Ink cylinder, 51... Air hole provided on the side surface of the ink cylinder, 7... Holder.

Claims (1)

[Scope of utility model registration request] In a writing instrument in which an ink cylinder with a pen tip attached to the tip and an open end is built into the barrel, the vapor pressure of the ink is measured between the end of the ink cylinder, which contains ink with a space left at the end, and the bottom of the barrel. A holder impregnated with an anti-drying agent made of a liquid with a vapor pressure higher than that of An ink drying prevention device for a writing instrument, characterized in that the space between the inner peripheral surfaces of the barrel is communicated.