JPS6090775A - Heat-fusible type ink jet recorder - Google Patents

Abstract

PURPOSE:To reduce the period of time required for heating at the time of starting, enable to simplify construction and to reduce size, simplify the construction of an ink-supplying part and obtain the titled recorder excellent in maintainability and operability, by jetting a heat-fusible ink while selectively controlling by an electrostatic attractive force. CONSTITUTION:The recorder comprises an ink-supplying part 2 for appropriately supplying a granular or lump form heat-fusible ink 1, a heating container part 3 having a holed construction for receiving the ink 11 supplied from the part 2 and heating the ink 11 to melt the latter, an ink-jetting substrate 6 receiving and reserving the liquid ink 12 supplied from the container part 3 and provided with a plurality of electrodes 4 arranged in a plate form and a heating means 5, a plurality of counter electrodes 8 arranged on the back side of a recording paper 7 and provided with a polarity opposite to that of the electrodes 4, and an ink jet controlling part 9 for selectively impressing voltages on the electrodes 4, 8 in accordance with an image signal to jet the ink as ink droplets 13 by electrostatic attractive forces. The liquefied ink is caused to fly to record an image on the paper 7.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a hot-melt inkjet recording apparatus that records an image on recording paper by heating hot-melting ink and ejecting the ink into a fluid or liquid state.

BACKGROUND ART Conventionally, inkjet recording devices apply heat pulses to the ink in the nozzle by pressure excitation of the ink in a liquid state at room temperature from the nozzle or by electrostatic attraction from the tip of a needle-like electrode, thereby increasing the temperature of the ink. It has been put into practical use as a method of ejecting and flying ink droplets using the rapid rise and expansion force of generated bubbles to form an image on recording paper. However, in this method of writing and printing images by ejecting ink that is in a liquid state at room temperature, water or a solvent is used as the ink medium. These liquid components evaporate from the ink surface exposed to the ink, causing a change in the ink composition and an increase in ink viscosity.
Furthermore, it causes the phenomena of drying, drying, and solidification of the ink, and therefore, the ink cannot be ejected stably or cannot be ejected, resulting in instability such as density unevenness, missing images, etc. in the recorded image, or It had serious drawbacks, such as being disabled.

In other words, the method of ejecting ink from a single nozzle, multi-nozzle, or a nozzle with an elongated opening in the form of a slit causes the problem of nozzle clogging, or the magnetic ink is supplied to the needle-like polarized tip using a magnet or electromagnet. In this method, there arises the problem of vaporization of the liquid component from the ink supply section exposed to the outside air, resulting in drying and solidification of the ink. Although the ejection method using heat pulses described above has the effect of ejecting and removing clogged nozzles with high pressure due to expansion force, it also suffers from image re-J Stability cannot be resolved.

To avoid such ink drying and assimilation problems, when the recording device is not in use, cover the nozzle with a cap, or cover the ink supply section to prevent the ink surface from being exposed to the outside air. Alternatively, an arrangement is made in which the ink liquid level is maintained at a constant vapor pressure in a closed system. Measures have also been taken, such as collecting ink from the ink ejecting unit, ink supply unit, etc. that is exposed to the outside air by returning it to the supply tank, and cleaning the parts that are exposed to the outside air. However, none of the measures to prevent ink drying is complicated by the structure of the device.
This has the drawbacks of increasing the cost of the device due to tediousness, and making practical operation cumbersome.

There have also been attempts to add additives to the ink for the purpose of drying it.However, it has been an essentially unavoidable problem to completely prevent evaporation of liquid components when the recording device is not in use.

As a recording method that fundamentally solves the drawbacks of ink drying and assimilation in inkjet recording devices that use ink that is in a liquid state at room temperature, Japanese Patent Application Laid-Open No. 113462/1983 proposes that the ink is in a solid state at room temperature and is in a solid state at 40°C or higher. This patent discloses a method of recording an image by using liquid hot-melting main ink and ejecting the ink that has been heated to become liquid. In this method, when the recording device is not used, the ink is in a solid state, and there is almost no change in the composition of the ink, and stable recording can be performed by heating and melting again. In a recording device using this heat-melting ink, it is required to shorten the heating time until the solid ink reaches a melted or fluid state and to simplify the heating means in the preparation stage before starting recording at startup. It has been desired to simplify the device configuration, that is, to make it smaller.

DISCLOSURE OF THE INVENTION The present invention avoids the drawbacks of ink drying in conventional inkjet recording devices that use ink that is liquid at room temperature, and uses a heat-melting inkjet recording method to print the ink until it reaches a fluid state where it can be jetted. To provide a heat-melting type inkjet recording device having a simple and miniaturizable configuration that shortens the time required for heating at startup, an extremely simple configuration of an ink supply section, and having ambiguous maintainability and productivity. It was made for the purpose of

The present invention uses a hot-melt ink that is solid at room temperature and becomes fluid or molten at temperatures above 40°C.

Further, in the present invention, a heat-melting ink containing soft magnetic fine particles in a dispersed state can also be used, if necessary. The present invention, which uses this heat-melting ink, has the following configuration: an ink supply section that supplies the ink in the form of particles or lumps in a solid state; an ink heating container part having a perforated structure capable of receiving solid ink from a supply part; and an ink heating container part arranged below the container part and having a structure capable of receiving liquid ink flowing out from the heating container part, and arranged at one end with a heating means. an ink ejecting substrate comprising a plurality of electrodes, several counter electrodes arranged on the back side of the recording paper and having opposite polarity to the electrodes; and an ink ejection control section that applies voltage and ejects ink using electrostatic attraction.

The present invention provides a bipedal ink jetting substrate having the following configuration: 1. The ink jetting substrate has a microporous structure that supplies the liquid ink on the substrate to the tip of the electrode on the substrate by capillary action. A layer can be provided and configured on a substrate. Further, the ink jetting substrate is provided with a magnetic field generating means that uses a hot melt ink containing soft magnetic fine particles in a fractional state and can supply the ink on the ink jetting substrate to the tip of the Pt pole on the substrate by magnetic force. It can also be configured.

Furthermore, it is also possible to make the end face of the ink ejecting substrate have an uneven structure, and to arrange +44t on the convex portion of the substrate.

According to the present invention, the solid heat-melting ink is put into the ink heating container part, becomes liquid, is supplied onto the ink substrate, and is ejected as ink droplets from the tip of the electrode by electrostatic attraction to the recording paper. An image is formed. Therefore, in the present invention, since the ink is in solid form, the ink replenishment work is easy, and the ink is supplied not by a supply pipe surrounded by a heater, but by an open system that is completely exposed to space, all the way to the electrode tip of the ink jetting board. The ink can be supplied, the number of heated parts is reduced, and the device (1, ilh structure is reduced to 1-11 elements, making it possible to downsize the device and being an open system, making maintenance easier. The amount of vaporization of heat-melting ink or hot-melt ink that solidifies when the recording/recording device is not in use is extremely small compared to conventional ink that is liquid at room temperature. However, all problems associated with ink drying are solved.The heating time required to turn solid ink into liquid at the time of startup is extremely shortened by the configuration of the present invention.In other words, in the heating container section, the inner wall of the container The ink in contact with the substrate easily melts and flows out, and since the ink on the ink substrate is spread out in a thin layer, it easily becomes liquid.

In addition, in conventional inkjet recording devices that use liquid ink at room temperature, a configuration has been proposed in which a heating means is installed on the rotating nozzle. The purpose, method, and effects are completely different from those of the present invention. Furthermore, the method of ejecting ink by applying a voltage between the counter electrodes is known for ejecting liquid ink at room temperature, but as is clear from the configuration of the present invention described above, since a heat-melting ink is used, The configuration of the electrode section on the substrate can be extremely simplified, and the above-mentioned excellent effects that have never been seen before can be obtained.The method of supplying magnetic ink to the tip of the electrode using rainbow magnetic force is also different from the conventional method when using liquid magnetic ink at room temperature. Although it is well known, in the above configuration of the present invention when hot-melting magnetic ink containing magnetic fine particles is used, other excellent effects similar to those described above can be obtained.

The heat-melting ink used in the present invention will be described. In order to avoid staining hands or other printed matter by touching the recorded image, heat-melting ink with a softening or melting temperature of 40° C. or higher is used. The ink contains paraffin, beeswax, waxes such as lanolin derivatives, lauric acid, stearic acid,
Fatty acids such as palmitic acid, acrylic, vinyl,
It is obtained by forming a heat-melting medium using a single component or a mixture of a plurality of thermoplastic resins such as cellulose resin, and then coloring the medium with a dye or pigment of a desired color. Alternatively, heat-melting dyes that exhibit heat-melting properties may be used alone or with the addition of a softening point regulator.
l11 raw ink is obtained. A thermofusible magnetic ink obtained by dispersing soft magnetic fine particles such as ferrite or magnetite in the thermofusible ink may also be used in the present invention. Naturally, it is possible to form a hot-melt ink with components other than those mentioned above, and the present invention does not particularly limit the component composition.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing the configuration of an embodiment of the present invention. 1st
In the figure, a solid hot melt formed into particles or lumps by spraying or pulverization; ``Supply of solid ink with a structure that can store magnetic ink 1 and supply it to the next process section as needed. The solid ink 11 discharged and supplied from the ink supply section 2 is received and heated to form a fluid or molten ink, which is then flowed out and supplied to the next process section. The ink heating container part 3 is formed by forming a perforated structure such as a liquid shape or a net shape with a heating resistor and a heat-resistant insulator such as ceramic or plastic, and the ink is supplied and flows out from the holes or gaps of the heating container part 3. liquid ink 12
It has a plate-like structure capable of receiving and storing ink, and has a plurality of electrodes 4 arranged at one end, and a planar heating means 5 arranged on the surface or back side of the ink side to heat the received ink (in Fig. ) and R of the recording paper 7.
A plurality of opposing electric bullets 8 with opposite polarity to the electrode 4 arranged on the surface, and a pressure applied to these counter electrodes 4 and 8, ink is ejected as ink droplets 13 by electrostatic attraction. The embodiment of the present invention is constituted by the injection control section 9.

As a material for the ink jetting substrate 6, a heat-resistant insulating plate similar to that described above or a metal plate in a structure insulated from the electrodes 4 can be used. However, the materials are not limited to these. Further, the shape of the substrate 6 is not limited to the rectangular shape shown in the figure. In order to prevent the liquid ink on the substrate 6 from flowing away unnecessarily from the periphery of the substrate 6 except for the electric droplet 4 portion on the ink jetting side, for example, a jetty-shaped edge 10 can be provided on the circumference of the substrate 6 to prevent the liquid ink from being wasted. Note that 14 is a heating control section for the heating container section 3 and the planar heating means 5. These parts 2, 3.6 are separated so that the ink 11, 12 is supplied from the supply part 2 to the container part 3 and from the container part 3 to the propellant substrate 6 through the air. will be placed. 'One pole 4 is placed in close contact with the substrate 6 by sputtering, vapor deposition, etc., and is heated during recording. There is nothing to do.

The ink on the substrate 6'' is efficiently supplied and jetted by tilting the substrate 6 by an appropriate amount.

Furthermore, a sponge-like or felt-like sheet made of Japanese paper or heat-resistant resin, a twisted wire, or a mesh wire-like metal sheet may be disposed on the ink-side surface of the ink jetting substrate 6, or fine grooves may be bored. The ink on the substrate 6 can be easily supplied to the electrodes 4 by utilizing capillarity caused by these microporous structure layers on the substrate 6.

Instead of the shape of the end face of the substrate 6 on the side where it is directly placed 4 in the above embodiment,
As shown in a perspective view of the ink jetting substrate 61 of the side structure in FIG. 2, the ink jetting substrate is arranged so that its end face has a serrated or wavy uneven structure and the electrodes 41 are disposed on this convex protrusion substrate. It can also be configured. This structure has the advantage that the ink on the substrate 61 concentrates on the electrode 41 and is easily picked up.

Next, an example will be described in which a heat-melting ink containing soft magnetic particles is used. In place of the single pole 40 of the above embodiment, an ink ejecting substrate is constructed by arranging needle-like magnets whose tips also serve as electrodes. The other configurations are exactly the same as in the above embodiment. With this configuration, the ink on the substrate can be easily supplied to the tip of the needle magnet by the magnetic force of the magnet. This needle magnet may be configured to protrude into the air from the end surface of the substrate,
In this case, high resolution recorded images can be obtained. A soft magnetic wire such as permalloy is placed in place of the above-mentioned needle magnet, and the magnetic wire is magnetized by approaching the magnet from the back of the board or by activating an electromagnet. Ink can be easily supplied to the tip of the electrode.

When using hot-melt ink containing magnetic fine particles, the heating temperature of the ink can be controlled to be lower than the temperature of the magnetic fine particles at one point, for example, 100°C or less, so the ink can be supplied without damaging the magnetic properties. .

The ink heating temperature of the present invention does not need to be extremely high, and the ink can be made into a liquid in the range of approximately 40 to 100°C, so the device configuration is easy without being limited to materials such as high-temperature heat. Moreover, the power consumption required for heating the ink is also reduced.

In the recording apparatus of the present invention described above, the supply and stop of the solid ink 11 from the ink supply section 2 are performed by detecting the amount of ink on the substrate 6, that is, the depth of the liquid ink layer, and opening and closing of the supply port 15 of the supply section 2. Since this can be controlled by using a solenoid valve or the like, it is possible to easily prevent the ink on the substrate 6 from overflowing and flowing away from the side end surface of the electrode 4. Further, according to the present invention, it is also possible to form the supply section 2 into a cassette to make replenishment of the solid ink 1 even easier.

As described above, according to the present invention, the ink drying problem of conventional inkjet recording devices that use liquid ink at room temperature can be solved, and the ink supply system and heating section can be improved by taking advantage of the heat-melting ink. It is possible to provide a heat-melting inkjet recording device that can simplify and downsize the device configuration, shorten the heating time in the preparation stage when starting the recording device, facilitate ink replenishment, and have excellent operability and maintainability. The ink jetting substrates of the present invention are stacked in four layers for each color: yellow, magenta, cyan, and black, and each color's heat-melting ink is tl?? By supplying the liquid separately through the supply section and the heating container section of the present invention, color recording can be performed and it can also be applied as a compact color recording device.

[Brief explanation of drawings]

The drawings are perspective views showing the structure of an embodiment of the present invention, with FIG. 1 showing a recording device and FIG. 2 showing an ink jetting substrate in an expanded state. 1.11.12... Hot melt ink, 2... Ink supply section, 3... Ink heating container section, 4.4-1... Electrode, 5... Heating means, 6, 61. . . . Ink jetting substrate, 7… Recording paper, 8… Counter electrode, 9… Ink jetting control unit. patent applicant

Claims (4)

[Claims] (1) A supply section for solid heat-fusible ink, an ink heating container section arranged separately from the supply section and receiving the solid heat-fusible ink supplied from the supply section, and an ink heating container section for receiving the solid heat-melt ink supplied from the supply section; an ink ejecting substrate disposed below and having a structure capable of receiving liquid hot-melt ink flowing out from the container portion, and comprising a heating means and a plurality of poles arranged at one end; and a back surface of the recording paper. A plurality of counter electrodes arranged in the opposite electrode and having a polarity opposite to that of the electrode, and an ink ejection control section that selectively applies a voltage to the counter electrode according to an image signal to eject ink. Heat-melting inkjet recording device. (2) Claim 1, characterized in that the substrate surface is provided with a microporous structure layer capable of supplying the liquid heat-melting ink on the ink jet substrate to the tip of the electrode at the end of the substrate by capillary action. The heat-melting inkjet recording device described above. (3) A patent characterized in that a hot-melt ink containing soft magnetic fine particles in a dispersed state is used, and the substrate is equipped with a magnetic field generating means capable of supplying liquid ink on the ink jetting substrate to the tip of the electrode by magnetic force. A heat-melting inkjet recording device according to claim 1. (4) The heat-melting inkjet ink jetting device according to claims 1 and 2, characterized in that the end face of the ink jetting substrate has an uneven structure and electrodes are arranged on the convex portion of the substrate.