JPS62267160A - Recording head and recording method using the same - Google Patents

Abstract

PURPOSE:To prevent generation of trailing or fog in an image, by forming a recording head so that a heat generating body may generate heat corresponding to an image signal and the ink in a housing is supplied to an ink sump through an ink passing hole and reduced in its viscosity to be transferred to a medium to be recorded. CONSTITUTION:An insulating substrate 4 and a heat generating body 5 comprising ruthenium oxide (RuO2) are provided to a part of a housing 2. At first, when a voltage pulse is applied to the heat generating body 5 through an electrode 7, the semisolid ink 3 in vicinity of the heat generating body 5 is heated. Said ink has a high viscosity at ambient temp. but when heated, it passes through ink passing holes 6 because its viscosity is reduced, and it spreads in the ink sump 9 and radiates heat at this time to again return to the semisolid state. Next, when voltage is applied to the heat generating body 5 corresponding to an image signal, said heat generating body 5 selectively generates heat and the semisolid ink 3 is lowered in its viscosity by said heat to be released from the ink sump 9 and transferred to recording paper 10. Therefore, trailing or fog is hard to generate in the transferred image and a sharp image can be recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a recording head used in, for example, an image processor, an electronic typewriter 1, a facsimile machine, various bulletin boards, etc., and a recording method using the recording head. be.

<Prior Art> Today, the thermal transfer recording method is the mainstream recording method for information processing. This recording method uses an ink film formed by coating a support with heat-melting ink, heats the ink film in an image pattern with a recording head, and transfers the molten ink onto recording paper. This method has the advantage that the device used can be made smaller and lighter, and recording can be performed on plain paper.

However, the thermal transfer recording method described above has drawbacks such as high running costs and complicated processing of used ink films because the ink film once used must be disposed of.

Therefore, in order to improve the above drawback, for example, as shown in FIG. 5, a heating element 5 of a recording head 1 used for thermal recording is
Some are provided with an ink passage hole 6 for the ink 3 to pass through (JP-A-59-118493, JP-A-59-225990, JP-A-60-4093, JP-A-Sho 60-4093, JP-A-Sho 60-4093). Publication No. 60-46264, JP-A-60-20
6677, etc.).

When this recording head 1 is used, when the housing 2 is filled with semi-solid ink 3 and the heating element 5 is made to generate heat, the ink near the heating element is softened and its viscosity is lowered, so that the ink flows through the passage hole. Pass 6.

Therefore, by forming the passage holes 6 in an array and applying a selective heating signal to each heating element 5, the recording paper IO
An ink image can be transferred and recorded thereon.

According to the above method, there are advantages such as low running costs because there is no need to use an ink film, and good thermal energy efficiency because the ink can be directly heated without using a film.

<Problems to be Solved by the Invention> However, in the above recording method, the ink passage hole and the recording paper come into direct contact and slide in this state, so there is a possibility that trailing or fogging may occur in the recorded image. There is.

The present invention solves the above-mentioned conventional problems and provides a recording head that does not require the use of an ink film and does not easily cause trailing, capri, etc. on images, and a recording method using the recording head.

<Means for Solving the Problems> The means of the present invention for solving the above-mentioned conventional problems includes a housing capable of storing ink, an insulating substrate provided on the housing, and an insulating substrate provided on the substrate and capable of storing image signals. a heating element that selectively generates heat depending on the temperature, an ink reservoir provided on the heating element and divided into a plurality of parts, an ink passage hole that communicates between the inside of the housing and the ink reservoir, and an ink reservoir from the housing to the ink reservoir; This method is characterized in that printing is performed using a print head having an ink supply means for supplying ink.

<Operation> According to the above means, when the ink reservoir portion of the recording head is brought into contact with the recording medium and the heating element is made to generate heat according to the image signal while moving the recording medium, the ink inside the housing is first supplied with the ink. The ink in the ink reservoir is supplied from the ink passage hole to the ink reservoir by the means, and the ink in the ink reservoir has a low viscosity and is transferred onto the recording medium, and immediately after that, the ink in the housing is replenished to the ink reservoir via the ink supply means. Ru.

Therefore, only the ink in the ink reservoir is transferred onto the recording medium, making it difficult for ink trailing to occur.

<Example> Next, an example of a recording means to which the above-mentioned means is applied will be described.

FIG. 1 is a schematic sectional view of a recording head, and FIG. 2 is an external view of a multi-type recording head in which the recording section of the recording head is arranged in seven layers in a line.

In the figure, l denotes a recording head, and inside the housing 2 there is a so-called thermal melting (including softening and sublimation) material which becomes a semi-solid and maintains high viscosity at room temperature, but whose viscosity decreases at high temperatures. It is designed to store ink 3.

A part of the housing 2 is provided with an insulating substrate 4 made of alumina (^l!03) and a heating element 5 made of ruthenium oxide (RuO□) on the substrate 4. As shown in FIG. 2, a plurality of ink inks are arranged in an array with 11 pitches, and four ink passage holes 6 each having a diameter of 0.2 mm are bored in each heating element 5 and substrate 4. There is.

Further, electrodes 7 made of gold (Au) that can be energized according to the image signal are connected to each of the heating elements 5, and by selectively applying a voltage to the electrodes 7, the heating elements 5 individually generate heat. is configured to do so.

Furthermore, a frame-shaped window 8 made of glass is continuously provided on the heating element 5, as shown in FIG. This window 8 has a thickness of 0.05+n, and has a rectangular ink reservoir 9 of 0.8×IX0,8 fins divided into a plurality of parts formed in an array on the heating element 5. This ink reservoir 9
The ink transferred from the ink forms the dots of the image. still,
The shape of the ink reservoir 9 is not limited to the rectangular shape as described above, but may be configured to correspond to the dots forming the image, for example, it may be circular.

When recording with the recording head 1, as shown in FIG. 1, the window 8 is brought into contact with the recording paper 10 which is the recording medium, and the recording paper 10 is moved by the platen roller 11 rotating in the direction of arrow a. A predetermined image is recorded while being transported.

Next, the case of recording using the recording head 1 will be explained with reference to FIG. 3.

First, a voltage pulse (24VX2
0 ms), the heating element 5 generates heat, and the semi-solid ink 3 near the heating element 5 is heated.

Since this ink has high viscosity at room temperature, it does not pass through the ink passage hole 6, but when heated as described above, the viscosity decreases and it passes through the ink passage hole 6.

As described above, the ink 3 that has passed through the ink passage hole 6 spreads into the ink reservoir 9, and returns to a semi-solid state or a state close to it due to heat dissipation at that time. At this time, a static pressure higher than the outside air pressure (about 0.1 atmosphere gauge pressure) is applied inside the housing 2 to promote the supply of ink to the ink reservoir 9.

As an ink supply means for supplying the ink into the ink reservoir 9, an air compressor 13 is used to apply static pressure, as shown in FIG. 4(A). In addition, 12 in the figure is an air introduction pipe. The air compressor 13 can apply a constant pressure to the ink 3 or apply a pressure pulse synchronized with the image signal.

Next, when a voltage is applied to the heating element 5 in accordance with the image signal, the heating element 5 selectively generates heat (the state shown in FIG. The ink becomes viscous, peels off from the ink reservoir 9, and is transferred onto the recording paper 10 that is being conveyed in the direction of the arrow (as shown in FIG. The ink 3 in the housing 2 whose viscosity has been reduced by the heat generated by the heating element 50 passes through the ink passage hole 6 and is replenished into the ink reservoir 9 (the state shown in FIG. 3(C)), and as described above, It becomes semi-solid due to heat dissipation as it spreads (Figure 3 (0)
) state).

By repeating the above steps in response to both signals, recording dots corresponding to the size of the ink reservoir 9 are continuously formed on the recording paper 10, and an ink image is transferred. At this time, the ink 3 is pressed in the direction of the ink passage hole 6 by the pressure applied by the ink supply means 13, so that the ink is smoothly replenished and transferred to the ink reservoir 9.

In the above process, in the recording head 1 of this embodiment, the depth of the ink reservoir 9 is 0.05 mm) and the radius of the ink passage hole 6 is (0.05 mm).
. Therefore, the ink 3 in the ink reservoir 9 becomes less viscous and is transferred onto the recording paper 10 a little faster than the timing at which the ink 3 in the ink passage hole 6 becomes less viscous and passes through the hole 6 .

That is, when one pulse of voltage is applied to the heating element 5, the ink 3 in the ink reservoir 9 is first transferred to the recording paper 10, and immediately after that, it passes through the ink passage hole 6 into the empty ink reservoir 9. The ink 3 that has been used is replenished.

Therefore, in order to perform the recording shown in this embodiment, it is preferable to set the depth of the ink reservoir 9 to be smaller than the radius of the ink passage hole 6. However, the present invention is not limited to the above configuration as described later.

Next, the ink 3 to be filled into the recording head 1 will be described. Typically, a heat-melting ink can be used. This hot-melt ink is made by dispersing or dissolving a coloring agent in a hot-melting binder, and elastomers and the like are added to the hot-melting binder to adjust the melt viscosity, adhesive strength, etc.

Heat-melting binders include various conventionally used natural or synthetic binders such as wax resins, etc.
Or a mixture of two or more types can be used.

The heat-melting binder constituting the ink includes natural waxes such as spermaceti wax, beeswax, lanolin, carnauba wax, candelilla wax, montan wax, and ceresin wax, petroleum waxes such as paraffin wax and microcrystalline wax, oxidized waxes, Ester wax, low molecular weight polyethylene, synthetic wax such as Finscher-Tropsch wax, lauric acid, myristic acid, valmitic acid, stearic acid, behenic acid, etc.”
High-grade fats, D-acid, higher alcohols such as stearyl alcohol and behenyl alcohol, fatty acid esters of sucrose,
Esters such as sorbitan fatty acid ester, amides such as oleylamide, polyamide resin, polyester resin, epoxy resin, polyurethane resin, polyacrylic resin, polyvinyl chloride resin, cellulose resin, polyvinyl alcohol type Resins, petroleum resins, phenolic resins, polystyrene resins, natural rubber, styrene-butadiene rubber, isoprene rubber, chloroprene rubber, and other elastomers, or plasticizers, mineral oils, vegetable oils, and other oils are appropriately mixed, and the melting temperature and Use by controlling melt viscosity.

As the coloring agent constituting the heat-melting ink together with the heat-melting binder, all dyes and pigments commonly used for printing carbon blanks or other recording methods are used, and these dyes and pigments may be used alone or in combination. A mixture of two or more types is used. The colorant content in the above ink is 1 to 1.
40% by weight is preferred.

Note that the ink 3 is not limited to one that is semi-solid at room temperature; for example, a paste-like one or a highly viscous one may be used.

As described above, according to the configuration of this embodiment, only the ink in the ink reservoir 9 is transferred onto the recording paper 10, and the ink reservoir 9 is smoothly replenished with ink, so that there is no ink trailing etc. in the image. can be transcribed and recorded.

In the above-described embodiment, the depth of the ink reservoir 9 was set smaller than the radius of the ink passage hole 6 to create a time difference between the heat conduction to the ink in the ink reservoir 9 and the ink inside the ink passage hole 6. Even if the structure is not as described above, heat conduction to the ink in the ink passage hole 6 can be achieved by providing a heat insulating layer inside the ink passage hole 6 or between the substrate 4 and the heat generating element 5. The heat conduction can be made slower than the heat conduction to the ink in the ink reservoir 9, and as a result, a process similar to the previous embodiment can be obtained by applying a single voltage pulse.

Further, the present invention does not need to be configured to print one dot by applying one pulse of voltage as described above.

For example, with the first pulse, Fig. 3 (A), (B
) as shown in FIG.
), one set of two pulses may be used to replenish the ink 3 into the ink reservoir 9, that is, the printing of one dot may be completed by causing the heating element 5 to generate heat twice. be.

In the above-mentioned embodiment, the air compressor 13 was used as the ink supply means to apply a static pressure higher than the outside pressure into the housing 2. A similar effect can be obtained by providing a piston 14 that presses the ink 3 in the housing 2 and operating the piston 14 to apply pressure to the ink 3 as shown in B).

Further, as an ink supply means, a pair of gear rotating bodies 15 are provided in the housing 2 as shown in FIG. 4(C), and pressure can be applied to the ink 3 by rotating each of these in the direction of arrow C. In this case, the ink 3 flows in the direction of arrow d in the figure and is supplied from the ink passage hole 6 to the ink reservoir 9. As described above, the ink supply means may be located outside the recording head 1 or may be located inside the housing 2.

Further, as the material constituting the substrate 4, in addition to ceramic materials such as alumina, glass, a metal plate coated with an insulating film, etc. can be used.

In addition to ruthenium oxide, the heating element 5 is made of Ta-N, Ni, etc.
It may be made of a material that can generate heat when energized, such as Cr-based or Cr-5iO□-based material.

In addition to gold, the electrode 7 can also be made of alloys such as aluminum, nickel, chromium, etc., copper, etc.

Furthermore, the magnitude of the voltage pulse applied to the heating element 5, the number of ink passage holes 6, and even the pressure applied to the ink are not limited to those of the above-mentioned embodiments, and may vary depending on the type of ink used and the ink passage. Of course, it may be changed as appropriate depending on the size of the hole 6 and the ink reservoir 9, etc.

Furthermore, although paper was used as the recording medium 10 in the above-mentioned embodiments, it is also possible to use paper, for example, which has a surface of fluorine-based resin or silicon-based resin, and which is used for so-called whiteboards, electronic blackboard sheets, etc. Even those with poor wettability can be used.

<Effects of the Invention> As described above, the present invention first supplies the ink in the housing to the ink reservoir by the ink supply means, lowers the viscosity of the ink in the ink reservoir, and transfers it onto the recording medium. Since the ink inside the tank is replenished into the ink reservoir through the ink passage hole, there is no need to use an ink film like in the past, and since only the ink inside the ink reservoir is transferred to the recording medium, transfer is possible. It is possible to record clear images without causing trailing or fogging on images.

Further, during recording, ink can be smoothly supplied to the ink reservoir by the ink supply means.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of a recording head according to an embodiment of the present invention, FIG. 2 is an external view of a multi-type recording head in which the recording parts of the recording head are arrayed in a line, and FIG. 3 (8) ~
(D) is an explanatory diagram of the recording process, Fig. 4 (A) (B) (
C) is an explanatory diagram of the pressurizing means, and FIG. 5 is an explanatory diagram of the prior art. 1 is a recording head, 2 is a housing, 3 is ink, 4 is a substrate, 5 is a heating element, 6 is an ink passage hole, 7 is an electrode, 8 is a window, 9 is an ink reservoir, 10 is a recording paper, 11 is a platen roller , 12 is an air introduction pipe, 13 is an air compressor, 14 is a piston, and 15 is a gear rotating body.

Claims (4)

[Claims] (1) A housing capable of storing ink, an insulating substrate provided on the housing, a heating element provided on the substrate and selectively generating heat according to an image signal, and a plurality of heating elements provided on the heating element. A recording head comprising an ink reservoir divided into two parts, an ink passage hole that communicates the inside of the housing with the ink reservoir, and an ink supply means that supplies ink from the housing to the ink reservoir. (2) The recording head according to claim 1, wherein the ink supply means is constituted by a pressure means. (3) The recording head according to claim 1, wherein the depth of the ink reservoir is smaller than the radius of the ink passage hole. (4) The ink reservoir of the recording head, which has a plurality of divided ink reservoirs communicated with the inside of the housing on the heating element, and has means for supplying ink to the ink reservoirs, is brought into contact with the recording medium. At the same time, the heating element is selectively heated to reduce the viscosity of the ink, the ink in the ink reservoir is transferred onto the recording medium, and the ink with the reduced viscosity is supplied to the ink supply means. A recording method characterized by supplying ink into the reservoir through the ink reservoir.