JP2011079206A - Thermochromic writing utensil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermochromic writing utensil that can surely intercept ventilation between the inside of a shaft cylinder and the outside of the shaft cylinder in the rear end opening of the shaft cylinder mounted with a friction body. <P>SOLUTION: The rear end of the shaft cylinder 2 is provided with a friction body 5 rubbing against thermochromic handwriting in thermochromic ink to thermally discolor the thermochromic handwriting with frictional heat generated at that time. An engaging protrusion 21 is formed on the rear end opening inner surface of the shaft cylinder 2. An annular inner seal part 22 is provided on the rear end opening inner surface of the shaft cylinder 2 in front of the engaging protrusion 21. The friction body 5 includes a front side bulging part 51 having an annular outer seal part 51a on the outer surface; an engaging recess 53 connected to the rear part of the front side bulging part 51; and a rear side bulging part 52 connected to the rear part of the engaging recess 53. The engaging protrusion 21 is engaged with the engaging recess 53. The rear side bulging part 52 is projected backward from the rear end of the shaft cylinder 2. The outer seal part 51a and the inner seal part 22 are airtightly suitable for each other to intercept ventilation between the inside of the shaft cylinder 2 and the outside of the shaft cylinder 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a thermochromic writing instrument. Specifically, thermochromic ink is accommodated inside the shaft tube, a pen tip capable of discharging the thermochromic ink is provided at the front end of the shaft tube, and the thermochromic ink is disposed at the rear end of the shaft tube. The present invention relates to a thermochromic writing instrument provided with a friction body for rubbing the thermochromic handwriting by rubbing and thermally discoloring the thermochromic handwriting by frictional heat generated at that time.

Conventionally, in this type of writing instrument, for example, Patent Document 1 describes a configuration in which a friction body for thermally discoloring a thermochromic handwriting by frictional heat is provided at the rear end of the shaft cylinder. In the above-mentioned Patent Document 1, when the writing instrument is a gel ink ballpoint pen provided with an ink backflow prevention body, ventilation between the shaft cylinder inner space behind the ink backflow prevention body and the outside of the shaft cylinder is necessary. Describes a structure that allows ventilation between the inside of the shaft tube and the outside of the shaft tube by a friction body provided with a vent hole.

JP 2008-155624 A

In the conventional thermochromic writing instrument, a friction body is attached to the rear end opening of the shaft tube, and the ventilation between the inner side of the shaft tube and the outside of the shaft tube at the rear end opening of the shaft tube can be reliably blocked. Not proposed.

An object of the present invention is to provide a thermochromic writing instrument capable of reliably blocking the ventilation between the inside of the shaft tube and the outside of the shaft tube at the rear end opening of the shaft tube to which the friction body is attached.
In the present invention, “front” refers to the pen tip side, and “rear” refers to the opposite side (friction body side).

<1> A first invention of the present application includes a pen tip 4 that accommodates thermochromic ink in a shaft tube 2 and can discharge the thermochromic ink at a front end of the shaft tube 2. 2 is a thermochromic writing instrument provided with a friction body 5 for rubbing the thermochromic handwriting by the thermochromic ink at the rear end of the base plate 2 and rubbing the thermochromic handwriting with frictional heat generated at that time. An engagement convex portion 21 is formed on the inner surface of the rear end opening of the shaft cylinder 2, and an annular inner seal portion 22 is provided on the inner surface of the rear end opening portion of the shaft cylinder 2 in front of the engagement convex portion 21. The body 5 includes a front bulging portion 51 having an annular outer seal portion 51 a on the outer surface, an engaging recess 53 provided continuously behind the front bulging portion 51, and a rear side of the engaging recess 53. The rear bulging portion 52 is engaged with the engaging convex portion 21 and the engaging concave portion 53 so that the rear bulging portion 52 is located behind the rear end of the shaft tube 2. And the outer seal portion 51a and the inner seal portion 22 are hermetically fitted to block the ventilation between the inside of the shaft tube 2 and the outside of the shaft tube 2 at the rear end opening of the shaft tube 2. As a requirement.

In the thermochromic writing instrument 1 of the first invention, the inner side of the shaft cylinder 2 at the rear end opening of the shaft cylinder 2 to which the friction body 5 is attached is formed by airtightly fitting the outer seal portion 51a and the inner seal portion 22. And the outside of the shaft cylinder 2 can be reliably blocked. In the thermochromic writing instrument 1 of the first invention, the rear end opening of the shaft tube 2 is directly sealed by the friction body 5, and the inside of the shaft tube 2 and the shaft tube through the rear end opening of the shaft tube 2 are sealed. 2 Because of the configuration that blocks ventilation between the outside, an increase in the number of parts can be suppressed.

<2> According to a second invention of the present application, in the thermochromic writing instrument 1 of the first invention, the maximum outer diameter of the rear bulge portion 52 is set smaller than the inner diameter of the inner seal portion 22, It is a requirement that the rear bulging portion 52 engages the engaging convex portion 21 and the engaging concave portion 53 by moving over the engaging convex portion 21 from the front to the rear.

The thermochromic writing instrument 1 according to the second aspect of the invention makes it easy to insert and assemble the friction body 5 due to the above configuration.

<3> The third invention of the present application is that, in the thermochromic writing instrument 1 of the first or second invention, the outer diameter of the rear end portion 51 of the friction body 5 is larger than the inner diameter of the engaging convex portion 21. And the outer diameter of the front end portion of the rear bulge portion 52 of the friction body 5 is larger than the inner diameter of the engaging convex portion 21.

In the thermochromic writing instrument 1 according to the third aspect of the present invention, the friction body 5 moves forward (i.e., the friction body 5) by the contact between the front end portion of the rear bulge portion 52 and the engagement convex portion 21. Is buried in the shaft cylinder 2, and the rear end portion of the front-side bulged portion 51 and the engagement convex portion 21 abut against the rearward movement of the friction body 5 (that is, to the outside of the friction body 5). Omission) is prevented. That is, the thermochromic writing instrument according to the third aspect of the present invention can reliably prevent the friction body 5 from moving back and forth, and can maintain a firm attachment state of the friction body 5.

The thermochromic writing instrument of the present invention can reliably block ventilation between the inside of the shaft tube and the outside of the shaft tube at the rear end opening of the shaft tube to which the friction body is attached.

It is a longitudinal section of an embodiment of the invention. It is a principal part enlarged view of FIG. It is a principal part enlarged view which shows the attachment process of the friction body of FIG.

A first embodiment of the present invention will be described (see FIGS. 1 to 3).

The thermochromic writing instrument 1 of the present embodiment is connected to a shaft cylinder 2, an ink occlusion body 3 housed in the shaft cylinder 2 and impregnated with thermochromic ink inside, and the ink occlusion body 3. The pen tip 4 is attached to the front end opening of the shaft tube 2 and the friction body 5 is attached to the rear end opening of the shaft tube 2.

Shaft cylinder The shaft cylinder 2 includes a cylindrical front shaft 2a and a cylindrical rear shaft 2b. The rear end portion of the front shaft 2a and the front end portion of the rear shaft 2b are connected by screwing or fitting. The front shaft 2a and the rear shaft 2b are obtained from a molded body of synthetic resin (for example, polypropylene).

An annular engagement convex portion 21 is integrally formed on the inner surface of the rear end opening of the shaft cylinder 2 (rear shaft 2b). The front surface and the rear surface of the engaging convex portion 21 are vertical surfaces. An inner seal portion 22 made of an annular smooth surface is formed on the inner surface of the rear end opening of the shaft cylinder 2 (rear shaft 2b) in front of the engaging convex portion 21. A plurality of ribs 23 extending in the axial direction are integrally formed on the inner surface of the shaft cylinder 2 in front of the inner seal portion 22.

Ink occlusion body The ink occlusion body 3 only needs to be made of a member having continuous pores that can be impregnated with ink (that is, a porous material). Examples include a processed body, a felt resin processed body, a felt needle punch processed body, and an open-cell body of a synthetic resin. In addition, the ink occlusion body 3 may be configured to have an outer skin made of a synthetic resin film or the like on the outer peripheral surface thereof.

The ink occlusion body 3 is impregnated with thermochromic ink. Examples of the thermochromic ink include a type that decolors by heating or a type that develops color by heating. The rear end of the ink occlusion body 3 is brought into contact with a rib 23 on the inner surface of the shaft cylinder 2. Further, the rear end portion of the pen tip 4 is pierced and connected to the front surface of the ink occlusion body 3.

Pen nib The nib 4 is attached to the inner surface of the front end opening of the shaft cylinder 2 (front shaft 2a). Thermochromic ink is ejected from the nib 4. The nib 4 is made of a fiber resin processed body. In addition to this, the nib 4 may be, for example, a ball-point pen tip, a heat-bonded processed body of fiber bundles, a felt processed body, a pipe-shaped pen body, a fountain pen type plate-shaped pen body having a slit at the tip, a brush pen body, Examples thereof include a porous foam of a synthetic resin and an extruded product of a synthetic resin having an axial ink guide path.

Friction body The friction body 5 is formed of a molded body of an elastic material having a bottomed cylindrical shape. The friction body 5 includes a front bulging portion 51, an engagement recess 53 provided continuously behind the front bulge 51, and a rear bulge 52 provided continuously behind the engagement recess 53. It consists of. The front bulging portion 51 has a substantially cylindrical outer surface, and an outer seal portion 51a made of an annular protrusion is integrally formed on the outer surface. The rear-side bulging portion 52 has a shape in which the outer diameter decreases toward the rear, and the rear end portion is formed in a convex curved shape. The engagement recess 53 is dimensioned so that the engagement protrusion 21 can be engaged. That is, the outer diameter of the rear end of the front bulged portion 51 is set larger than the inner diameter of the engaging convex portion 21, and the outer diameter of the front end of the rear bulged portion 52 is set larger than the inner diameter of the engaging convex portion 21. Is done.

Further, the maximum outer diameter of the rear bulge portion 52 is set smaller than the inner diameter of the inner seal portion 22 (or the outer diameter of the outer seal portion 51a). Thus, the rear bulge portion 52 can be prevented from fitting into the inner seal portion 22 before getting over the engagement convex portion 21, and the friction body 5 can be easily attached.

Examples of the elastic material of the friction body 5 include elastic resin materials such as SBS resin, SEBS resin, and silicone resin. The elastic material constituting the friction body 5 is made of a low-abrasion elastic resin that hardly causes wear debris (erasing debris) during friction, rather than a high-abrasion elastic resin (for example, an eraser). Is adopted. When the thermal discoloration handwriting by the thermochromic ink is rubbed by using the rear side bulging portion 52 of the friction body 5, the thermochromic handwriting is thermally discolored by frictional heat generated at that time.

Action The friction body 5 is inserted rearward from the inside of the shaft cylinder 2 (rear shaft 2b). Then, the rear bulging portion 52 rides over the engaging convex portion 21 on the inner surface of the rear end opening of the shaft cylinder 2 from the front to the rear, and the rear bulging portion 52 projects outward from the rear end of the shaft cylinder 2. At the same time, the engagement recess 53 of the friction body 5 is engaged with the engagement protrusion 21 on the inner surface of the rear end opening of the shaft cylinder 2. At the same time, the outer seal portion 51a of the friction body 5 and the inner seal portion 22 on the inner surface of the rear end opening of the shaft cylinder 2 are airtightly fitted. By the airtight fitting of the outer seal portion 51a and the inner seal portion 22, the ventilation through the rear end opening of the shaft tube 2 between the shaft tube 2 and the shaft tube 2 is reliably blocked.

DESCRIPTION OF SYMBOLS 1 Thermochromic writing instrument 2 Shaft cylinder 2a Front shaft 2b Rear shaft 21 Engaging convex part 22 Inner seal part 23 Rib 3 Ink occlusion body 4 Pen tip 5 Friction body 51 Front side bulging part 51a Outer seal part 52 Rear side bulging part 53 Engaging recess

Claims (3)

A thermochromic ink is accommodated inside the shaft cylinder, a pen tip capable of discharging the thermochromic ink is provided at the front end of the shaft cylinder, and the thermochromic property by the thermochromic ink is provided at the rear end of the shaft cylinder. This is a thermochromic writing instrument provided with a frictional body that rubs the handwriting and heats the thermochromic handwriting with the frictional heat generated at that time, and forms an engaging projection on the inner surface of the rear end opening of the shaft tube. An annular inner seal portion is provided on the inner surface of the rear end opening of the shaft cylinder ahead of the engagement convex portion, and the friction body has a front bulge portion having an annular outer seal portion on the outer surface, and the front bulge portion. An engaging recess provided continuously to the rear of the protruding portion and a rear bulging portion provided continuously to the rear of the engaging recess. By projecting the bulging portion rearward from the rear end of the shaft tube and airtightly fitting the outer seal portion and the inner seal portion, Thermochromic writing instrument, characterized in that blocks the air between the cylinder inside and the barrel outside. The maximum outer diameter of the rear bulge portion is set smaller than the inner diameter of the inner seal portion, and the rear bulge portion of the friction body climbs over the engagement convex portion from the front to the rear so that the engagement convex portion and the engagement concave portion The thermochromic writing instrument according to claim 1, wherein The rear end outer diameter of the front bulge portion of the friction body is larger than the inner diameter of the engagement convex portion, and the front end outer diameter of the rear bulge portion of the friction body is larger than the inner diameter of the engagement convex portion. Item 3. The thermochromic writing instrument according to item 1 or 2.

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