WO2015046257A1

WO2015046257A1 - Color changing device for thermochromic ink

Info

Publication number: WO2015046257A1
Application number: PCT/JP2014/075305
Authority: WO
Inventors: 洋幸小山
Original assignee: タイコエレクトロニクスジャパン合同会社
Priority date: 2013-09-26
Filing date: 2014-09-24
Publication date: 2015-04-02
Also published as: CN105579244A; JP6377066B2; JPWO2015046257A1; KR20160062040A; CN105579244B

Abstract

The present invention provides a color changing device for thermochromic ink, said color changing device being capable of changing the color of thermochromic ink without putting a load on paper. The color changing device for thermochromic ink has a PTC element.

Description

Thermochromic ink color changing device

The present invention relates to a color changing device for thermochromic ink.

Conventionally, a writing line or image formed on a paper surface with thermochromic ink rubs the paper surface on which the writing line or image is formed with a friction body using an elastomer material, and uses frictional heat generated at that time. Thus, it is thermally discolored (Patent Document 1).

On the other hand, a method has been reported in which a writing line or an image formed with thermochromic ink is erased by an erasing apparatus incorporating a heating element (for example, a heater) using a resistor (for example, nichrome line) (patent) Reference 2).

JP 2013-95013 A JP 2012-35612 A

When the thermochromic ink is discolored by a friction body using an elastomer material as described in Patent Document 1, it is necessary to rub the paper surface directly, so there is a problem that the paper is burdened and in the worst case the paper is torn. It was.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a thermochromic ink color changing device that can change the color of a thermochromic ink without imposing a burden on paper. .

Also, when rubbing the paper surface to obtain frictional heat, it is inevitably necessary to rub a certain range with a friction body, and therefore it is difficult to discolor fine areas. For example, there is a problem that even if only a part of the writing line is to be erased, other writing lines existing in the vicinity are also erased. Further, when a writing line such as a pencil is present in the vicinity, there is also a problem that the writing line of the pencil blurs because the writing line is rubbed. Furthermore, when rubbing the paper surface, the dirt adhering to the friction body is transferred to the paper surface, and the paper surface becomes dirty.

Also, it is difficult to control the heat obtained by friction, and particularly when trying to obtain a high temperature, it is necessary to rub more strongly and vigorously, and the above problem becomes more remarkable. For this reason, conventional thermochromic inks intended for discoloration by friction bodies are designed to change color at about 65 ° C. However, this relatively low temperature of 65 ° C. is a temperature that can be reached, for example, on the surface of an electronic device, near a heating device, in a car in the summer, etc. There is a possibility of discoloration. In particular, portable devices such as smartphones and tablet terminals have been spreading in recent years, and such devices and notebooks filled with, for example, thermochromic ink come into contact with each other in pockets, bags, etc. As a result, the thermochromic ink changes color, and the contents entered in the notebook may be erased.

On the other hand, when a heating element (for example, a heater) using a resistor (for example, nichrome wire) is used as described in Patent Document 2, it is not necessary to directly rub the paper surface. In order to prevent the damage, a mechanism for controlling heat generation, for example, a mechanism for controlling energization is required, which is structurally complicated. Structural complexity is disadvantageous in terms of manufacturing, miniaturization, cost, and the like.

Accordingly, the present invention is preferably a thermochromic ink discoloration device, which allows discoloration of fine areas, can discolor thermochromic ink that discolors at higher temperatures, and / or a structure. It is an object of the present invention to provide a thermochromic ink discoloration device that is simple.

As a result of intensive studies to solve the above problems, the present inventor uses a PTC (positive temperature coefficient) element and changes the color of the thermochromic ink by Joule heat generated by energizing the PTC element. I found that the problem could be solved.

That is, the present invention provides a color change device for thermochromic ink having a PTC element.

By using the PTC element, it is possible to provide a thermochromic ink color changing device capable of changing the color of the thermochromic ink without imposing a burden on the paper. In addition, by appropriately setting the area of the portion in contact with the thermochromic ink to be changed in color, accurate and precise erasure or a wide range of erasure becomes possible. Furthermore, by selecting a PTC element having a desired trip temperature, it is possible to change the color of the thermochromic ink that changes its color at a higher temperature than before, and the range of selection of the color change temperature of the thermochromic ink becomes wider.

FIG. 1A schematically shows a cross-sectional view of a thermochromic ink color changing apparatus 1 according to an embodiment of the present invention. FIG. 1B schematically shows a state in which the thermochromic ink color changing apparatus 1 shown in FIG. FIG. 2A schematically shows a cross-sectional view of the thermochromic ink color changing device shown in FIG. 1A covered with resin. FIG. 2B schematically shows a cross-sectional view of the thermochromic ink color changing device shown in FIG. 2A attached to the support member. FIG. 3A schematically shows a color changing device for an eraser type thermochromic ink. FIG. 3B schematically shows a cross-sectional view of the thermochromic ink color changing device shown in FIG.

As used herein, the term “discoloration” refers to the change of color from one color to another, as well as the disappearance of one color to become clear and disappear, and the color change from colorless to clear to a certain color. It also means to do.

The thermochromic ink color changing device of the present invention has a PTC element, and changes the color of the thermochromic ink by Joule heat generated by energizing the PTC element.

The PTC element used in the thermochromic ink color changing device of the present invention is not particularly limited, and a conventionally used PTC element such as a polymer PTC element or a ceramic PTC element can be used.

It is preferable to use a polymer PTC element as the PTC element. The polymer PTC element is advantageous in that self-destruction is less likely to occur even when the temperature exceeds a certain level, compared to the ceramic PTC element. In addition, the polymer PTC element has a lower voltage applied to maintain the trip state than the ceramic PTC element, and can maintain the trip state even when the circuit voltage is low. Therefore, even when the voltage of the battery is lowered, the trip state can be reliably maintained, and it is advantageous in that the power consumption can be reduced. The polymer PTC element is advantageous in that it can be easily processed as compared with the ceramic PTC element.

The polymer PTC element is formed by extruding a conductive composition containing a polymer (for example, polyethylene, polyvinylidene fluoride, etc.) in which a conductive filler (for example, carbon black, nickel alloy, etc.) is dispersed. And the electrode (for example, metal foil) arranged on both sides thereof. However, other elements such as leads may be directly connected to the PTC element, in which case the electrode can be omitted.

The size and shape of the PTC element used in the present invention are not particularly limited, and can be appropriately selected according to the purpose. For example, a smaller PTC element can be used for the purpose of discoloration of a fine region, and a larger PTC element can be used for a purpose of a wide range of discoloration. Moreover, it can be set as arbitrary shapes according to the shape of the casing etc. which incorporate a PTC element.

The PTC element used in the present invention is not particularly limited, but is preferably one that consumes less power during tripping. For example, a PTC element with a power consumption during trip of 1 W or less is preferable, and a PTC element with 0.5 W or less is more preferable. Battery consumption can be reduced by reducing power consumption during tripping.

The temperature at the time of trip of the PTC element used in the present invention, that is, the temperature when the PTC element trips and becomes high resistance, that is, the resistance value becomes 10 ³ times or more of the resistance value at 25 ° C. Simply referred to as “trip temperature”) can be appropriately selected according to the color change temperature of the thermochromic ink to be changed in color. The trip temperature of the PTC element is not particularly limited, and may be, for example, 65 ° C or higher, 70 ° C or higher, 80 ° C or higher, 90 ° C or higher, 100 ° C or higher, 110 ° C or higher, or 120 ° C or higher. it can. In addition, since there exists a possibility of damaging paper and an apparatus when temperature is too high, it is preferable that it is 130 degrees C or less, for example. The trip temperature of the PTC element is unique to the PTC element, and a PTC element having a desired trip temperature is commercially available.

As described above, the thermochromic ink color changing device of the present invention changes the thermochromic ink at an arbitrary temperature by selecting a PTC element having a desired trip temperature from PTC elements having various trip temperatures. Can be designed to let Therefore, by using the thermochromic ink color changing device of the present invention, the color changing temperature of the thermochromic ink to be changed is in a wide range including high temperature, for example, 40 to 150 ° C., preferably 65 ° C. to 130 ° C. It becomes possible to select from the range.

The thermochromic ink color changing device of the present invention may be supplied with electric power from an external power source, or may have a power source inside the device.

Examples of the external power source include a USB (Universal Serial Bus) power source provided in a PC (Personal Computer), a household outlet, and the like.

The power supply inside the above device is typically a battery. As such a battery, a generally available primary battery or secondary battery can be used. Further, the shape is not particularly limited, and may be, for example, a cylindrical shape, a button shape, a coin shape, a square shape or a flat shape. Moreover, a solar cell can also be used as a power supply.

The voltage of the battery (power source) used in the present invention is not particularly limited, and can be appropriately selected according to the PTC element used. For example, the voltage is 0.5 to 24 V, for example 1.0 to 12 V, specifically Specifically, it may be 1.5V, 3V or 9V.

In one embodiment, the thermochromic ink color changing device of the present invention may have a power source, particularly a battery, inside the device. By having a power source inside, portability and operability are improved.

In one embodiment, the thermochromic ink color changing device of the present invention comprises a switch. As such a switch, a commonly used switch can be used, and is not particularly limited, but a switch of a push button method, a slide method, a push pull method, an alternate method, a ratchet cam method or the like is used. be able to. Further, as described below, the lead can also have a switch function.

In one aspect, the thermochromic ink color changing device of the present invention comprises:
PTC element;
Power supply;
Switches; and leads that electrically connect the PTC elements, power supplies and / or switches;
Comprising a circuit comprising:
When the switch is turned on, the PTC element is energized to generate Joule heat, and the heat discoloration ink is discolored by this heat.

In the above circuit, the connection order of the PTC element, the power source and the switch is not particularly limited. Further, the lead may function as a switch as described below.

In the color changing device for thermochromic ink of the present invention, the elements such as the PTC element, the power source and the switch may be connected by leads or may be directly connected.

As means for directly connecting each element, for example, welding such as solder, conductive adhesive, laser welding, resistance welding or ultrasonic welding, or mechanical means can be used. As the mechanical means, caulking, pins, springs and the like can be used.

The circuit may include elements other than the PTC element, the power supply, and the switch, for example, a light emitting element that informs energization by light, such as a light bulb or an LED (light emitting diode), an element for confirming the remaining battery level .

In a preferred embodiment, the thermochromic ink discoloring device of the present invention further comprises a heat transfer section for transmitting heat generated in the PTC element to the thermochromic ink to be discolored.

Material forming the heat transfer unit is not particularly limited, metal materials (e.g., aluminum), resin materials (e.g., polyethylene), a ceramic material (e.g., alumina (Al 2 O _{_3)),} and the like. From the viewpoint of efficiently transferring heat generated in the PTC element to the thermochromic ink, a material having high thermal conductivity is preferable. Examples of the material having high thermal conductivity include metal materials such as aluminum and copper alloys. A material in which a resin or ceramic material having high thermal conductivity, for example, a metal filler (for example, aluminum or copper filler) or a ceramic filler (for example, alumina, boron nitride (NB), graphite filler) or the like is used may be used. it can. Further, from the viewpoint of easy molding into a desired shape, it is preferable to use a resin such as polyethylene or epoxy resin.

The shape of the heat transfer section is not particularly limited and can be appropriately selected depending on the purpose. For example, a rectangular parallelepiped shape, a cubic shape, a spherical shape, an elliptical spherical shape, a cone shape, or a shape obtained by cutting a part thereof, or those The shape which combined these may be sufficient. For example, when the purpose is to change the color of a fine region, the tip can have a narrow shape, for example, a conical shape. Moreover, when aiming at wide-range discoloration, it can be a shape having a large surface, for example, a rectangular parallelepiped shape.

In one embodiment, the thermochromic ink color changing device of the present invention may further have an exterior. The exterior protects each internal element and circuit and can also function as the heat transfer section.

The exterior is not particularly limited, and may be, for example, a general casing such as a resin casing, or may be formed by covering the apparatus with a coating material. By providing the exterior in this way, the color changing device and each element can be protected, and processing into an arbitrary shape is facilitated.

The coating material is not particularly limited, but an insulating material such as an insulating resin can be used. Although it does not specifically limit as said insulating resin, For example, a phenol resin, an epoxy resin, and a fluororesin are mentioned. The insulating resin is preferably one having high thermal conductivity such as polyethylene, epoxy resin, or silicone rubber so that Joule heat generated in the PTC element can be efficiently transmitted to the outer surface of the color changing device. In order to increase the thermal conductivity, the insulating resin may contain a ceramic material having a higher thermal conductivity than the insulating resin, for example, metal powder, alumina, silica or the like.

Also, a conductive material such as a metal material can be used as the covering material. However, when a conductive material is used, it is necessary to coat so that the circuit inside the color changing device for thermochromic ink does not short-circuit. Such a metal material is advantageous in that it has a high thermal conductivity and can efficiently transfer Joule heat generated in the PTC element to the outer surface of the thermochromic ink color changing device.

Hereinafter, the present invention will be described in detail with reference to the drawings. Throughout the drawings, elements denoted by the same reference numerals mean elements having substantially the same function.

FIG. 1 (a) schematically shows a cross section of a thermochromic ink discoloring device 1 which is an embodiment of the present invention.

In the illustrated embodiment, one electrode of the button battery 4 is electrically connected to one electrode of the PTC element 2, and one end 8 of the lead 6 is electrically connected to the other electrode of the PTC element 2. ing. The connection is not particularly limited, for example, by using a known technique, but using solder, solder paste, conductive adhesive, or the like, or using another device (for example, via a battery case). Can be done). As shown in the figure, the lead 6 wraps around, for example, in a U-shape from the side surface of the button battery to the other electrode (an electrode different from the electrode connected to the PTC element 2). Located electrically separated. In this state, the color changing device is not energized.

As shown in FIG. 1B, when a force in the vertical direction (the direction indicated by the arrow in FIG. 1B) is applied to the thermochromic ink color changing device 1 in the state shown in FIG. The end 10 of the lead 6 moves toward the electrode of the battery 4, and finally the end 10 and the electrode of the battery 4 come into contact with each other. As a result, a circuit of PTC element 2 -lead end 8 -lead end 10 -battery 4 -PTC element 2 is formed, and a current flows through PTC element 2. When the PTC element 2 is not tripped, the entire circuit has a low resistance, so that a current large enough to trip the PTC element flows. This current trips the PTC element 2 to generate Joule heat, which causes the thermochromic ink to change color.

In the illustrated embodiment, the lead 6 connects the PTC element 2 and the battery 4 and also functions as a switch. Specifically, when a force in the vertical direction (the direction indicated by the arrow in FIG. 1B) is applied to the thermochromic ink color changing device, the end 10 of the lead 6 and the electrode of the battery 4 come into contact with each other. 1b, and the circuit is closed. When the force applied to the thermochromic ink color changing device is removed, the end 10 of the lead 6 returns to the state shown in FIG. 1A, and the circuit is opened. That is, the lead 6 is deformed by a force applied in the vertical direction of the color changing device, and has a return property that returns to its original shape when the force is removed. A person skilled in the art can obtain appropriate returnability by appropriately adjusting the material used for the lead, the thickness and width of the lead. In the illustrated embodiment, the lead 6 has the function of a switch, but a switch can be separately provided.

The thermochromic ink color changing device of the present invention can change the target writing line or image simply by bringing the heated portion into contact with the writing line or image formed by the thermochromic ink to be changed in color. Therefore, there is no need to rub the paper surface, and the paper surface will not be damaged or soiled. In addition, by reducing the heating location, it is possible to change the color precisely, and conversely, by increasing the heating location, a wide range of writing lines or images can be changed at once.

The color changing device for thermochromic ink of the present invention can have a very simple structure as described above. In a thermochromic ink color change device using a general heating element using a resistor such as a nichrome wire as described in Patent Document 2, the heating element continues to be heated when an electric current is continuously applied, resulting in an abnormally high temperature. Since the body and the device may be damaged, a control device (control element) for adjusting the temperature of the heating element to an appropriate temperature is required. On the other hand, in the thermochromic ink color changing device of the present invention using a PTC element as a heating element, the trip temperature of the PTC element does not change greatly even if a current is continuously applied. Not required. Further, as apparent from the fact that the PTC element itself is used as a protective element for protecting the electronic device from overcurrent or the like, it can be used safely without using other control devices (control elements). be able to.

FIG. 2 (a) schematically shows a thermochromic ink color changing device covered with an insulating resin cover 12 as one preferred embodiment of the present invention, and FIG. 2 (b) shows it as a rod-like support. Sectional drawing of the state attached to the member 14 is shown typically.

The thermochromic ink discoloring device shown in FIG. 2A is obtained by covering the thermochromic ink discoloring device shown in FIG. 1A with an insulating resin cover 12 as an exterior. This resin cover also functions as a heat transfer section. The thermochromic ink color changing device shown in FIG. 2 (a) can be attached to a rod-like support member 14 (in the example shown, a pen), and can be formed into a pen shape as shown in FIG. 2 (b). By holding the support member 14 and pressing the insulating resin cover 12 against the paper surface, the projecting portion 16 presses the end portion 10 of the lead, the end portion 10 comes into contact with the battery 4, and the PTC element 2 is energized. .

FIG. 3 (a) schematically shows a thermochromic ink discoloring device of the present invention of an eraser type as another preferred embodiment, and FIG. 3 (b) schematically shows a cross-sectional view thereof.

The thermochromic ink color changing device of this embodiment is a rectangular parallelepiped, in which the button battery 4 of the color changing device of the thermochromic ink shown in FIG. 1A is replaced with a cylindrical battery (AA or AAA) 18. Is housed in a casing 20. The casing 20 corresponds to the exterior. The casing 20 has a heat transfer part 22 and a pressing part 24. By pushing the pressing portion 24, the end portion 10 of the lead comes into contact with the battery 4 and the PTC element 2 is energized.

By using such an eraser type, the contact portion between the color changing device of thermochromic ink and the paper surface can be enlarged, and a wide range of writing lines or images can be changed at once. Also, fine discoloration can be achieved by bringing only the end of the heated portion into contact with the paper surface.

The color changing device for the thermochromic ink of the present invention is not limited to the above-described embodiment, and any configuration may be used as long as it can energize and trip the PTC element. For example, in the embodiment shown in FIG. 1A, the battery 4 is installed inside the color changing device as a power source. However, even if power is supplied from the outside, for example, a battery attached to the outside or a USB power source. Good. Moreover, although the lead 6 has a switch function, it is also possible to install a switch separately. Furthermore, the thermochromic ink color changing device of the present invention may have elements other than those described above, such as an element for checking the remaining battery level.

DESCRIPTION OF SYMBOLS 1 ... Thermochromic ink color change apparatus 2 ... PTC element 4 ... Button battery 6 ... Lead 8 ... Lead end 10 ... Lead end 12 ... Insulating resin cover 14 ... Support member 16 ... Projection 18 ... AA Or AAA battery 20 ... casing 22 ... heat transfer part 24 ... pressing part

Claims

A thermochromic ink discoloring device comprising a PTC element.
The thermochromic ink discoloring device according to claim 1, further comprising a power source.
The thermochromic ink color changing device according to claim 2, wherein the power source is a battery.
The thermochromic ink discoloring device according to any one of claims 1 to 3, further comprising a switch.
PTC element;
Power supply;
Switches; and leads that electrically connect the PTC elements, power supplies and / or switches;
Comprising a circuit comprising:
5. The thermochromic ink according to claim 1, wherein a Joule heat is generated by energizing the PTC element by turning on the switch, and the thermochromic ink is discolored by this heat. Discoloration device.
The thermochromic ink color changing device according to claim 5, wherein the lead also functions as a switch.
The thermochromic ink discoloring device according to any one of claims 1 to 6, further comprising a heat transfer section for transmitting heat generated in the PTC element to the thermochromic ink to be discolored.
The thermochromic ink discoloration device according to any one of claims 1 to 7, further comprising an exterior.
The thermochromic ink discoloring device according to claim 8, wherein the exterior functions as a heat transfer unit.
The thermochromic ink discoloring device according to claim 8 or 9, wherein the outer casing is a cubic or rectangular parallelepiped casing.
11. The thermochromic ink discoloring device according to claim 8, wherein the exterior is formed of a coating material.
The thermochromic ink discoloring device according to claim 11, wherein the coating material is an insulating resin.
The thermochromic ink discoloring device according to any one of claims 1 to 12, wherein the PTC element is a polymer PTC element.
The thermochromic ink discoloration device according to any one of claims 1 to 13, wherein the temperature at the time of trip of the PTC element is 65 ° C or higher.
The thermochromic ink discoloring device according to any one of claims 1 to 14, wherein the temperature at the time of trip is 90 ° C or higher.
The thermochromic ink discoloring device according to any one of claims 1 to 15, wherein a temperature at the time of trip is 120 ° C.
The thermochromic ink discoloring device according to any one of claims 1 to 16, wherein power consumption at the time of trip of the PTC element is 1 W or less.
A writing instrument comprising the thermochromic ink discoloring device according to any one of claims 1 to 17.