JPS59162058A - Image recording apparatus - Google Patents

Abstract

PURPOSE:To make available image recording which would have been available by employment of heat-sensitive ink with a simple construction without resorting to heat-sensitive ink film and ink-recoating mechanism, by a pneumatic ink injection changing periodically in synchronization with heat generation of heating element which melts the heat-sensitive ink. CONSTITUTION:When heat generation occurs in a heater 3, bottom part of the heat-sensitive ink 8 is melted flowing to heating element 2, plugging a through- hole and solidifying to assume a solid phase after cooling by radiation of heat. When a plurality of heating elements 2 are heated through a pulse electric current selectively in response to an image signal, heat-sensitive ink found in its neighborhood is melted. As a pulse-generator 17 transmits periodically electricity to an electromagnetic solenoid 13, pressure in an air-tight chamber 1 changes in a range of higher pressure levels than the atmospheric pressure by aid of pneumatic valve 14. By this pneumatic pressure the heat-sensitive ink is injected to a recording member 9 and it is cooled and solidified to a dot to be recorded. Thus, a compact, light image recording apparatus can be formed of low maintenance costs become available without using such an expensive expendable as the heat-sensitive film.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image recording apparatus in which thermal ink is selectively melted by a heating element and recorded on a recording member such as paper using air pressure.

2. Description of the Related Art A thermal transfer method has conventionally been used as an image recording apparatus that records by thermally melting thermal ink. However, this method has drawbacks such as high running costs because it uses disposable thermal ink film, space required to process and store used thermal ink film, and restrictions on machine downsizing. be. One way to modify this is to replace the disposable thermal ink film with an endless tape or the like, and use an ink reapplying method in which thermal ink is applied at a location away from the recording paper. This method requires a heater to melt the thermal ink, a device to apply the ink evenly, and rollers and endless tape to apply the ink, making the machine complex and requiring both cost and space. One thing was not enough.

Furthermore, because the thermal ink comes into direct contact with the paper that is the recording member, paper dust adheres to the thermal ink and has an adverse effect, so it has not yet been commercialized.

The present invention has focused on this point and aims to provide an image recording device using thermal ink with a simple structure without using a thermal ink film or an ink reapplication mechanism. The details of one embodiment will be described below with reference to the drawings.

FIG. 1(A) is a schematic diagram showing the overall configuration of an embodiment of the present invention. The airtight container 1 usually has a plurality of heating elements 2 at the bottom.
It has a heater 3 that thermally melts the thermal ink 8 and guides it to the heating element 2, and a diaphragm 12 with a permanent magnet on the lower right side that generates periodically changing air pressure, an electromagnetic solenoid 16, and an electromagnetic solenoid 16 that drives the electromagnetic solenoid 16. It is equipped with a pulse generator 17 and has an air valve 14.

Further, the upper part of the airtight container 1 has a lid 7 which can be opened and closed via a backing 6, and a thermal ink 8 is stored inside. A recording paper 9 is placed close to the bottom of the heating element 2, and a platen 10 is arranged below it. The infrared lamp 11 is arranged so as to irradiate the recorded recording member.

FIG. 1 (11) is a top view showing the relationship between the heating element, the recording paper, and the platen.

FIG. 2 is a perspective view of a set of a heater and a heating element that transport thermal ink using capillary action.

Here, the shaded area represents molten thermal ink.

Figure 3 is an exploded view of the heat generating element 15, in which the heat generating element and the heater for transporting thermal ink using capillary action are made of the same material, and the thermal ink through-hole at the bottom of the airtight container. 16, but the top and bottom are separated for clarity. Note that the shaded portion of the heat generation/heater element 15 represents the molten thermal ink 8.

FIG. 4 is a diagram showing changes in air pressure and the timing of injection and supply of molten ink.

Next, the effect will be explained. In FIG. 1, thermal ink 8 is poured into an airtight container 1 with the lid 7 opened. After that, the lid 7 is closed and the backing 6 is used to maintain airtightness.

Here, thermal ink is a colored solid ink that is made by dispersing pigments, dyes, etc. in wax or the like, and is solid at room temperature and becomes liquid when the temperature is raised. When the heater 6 is energized by an electrode (not shown) to generate heat, the lower part of the thermal ink 8 melts and a part of it flows into the heating element 2.

The heating element 2 has a through hole, and the molten thermal ink flows and closes the through hole, radiating heat and cooling, and becomes solid. Next, in general, pulse current is selectively applied to a plurality of heating elements 2 using electrodes (not shown) in response to an image signal to generate heat, thereby melting the thermal ink in the corresponding portions. Heat generating element 2
is located on the bottom of the airtight container 1, and the pulse generator 17 connects the diaphragm 12 to periodically energize the electromagnetic solenoid 16.
is driven left and right periodically. Therefore, the air pressure inside the airtight container 1 changes periodically in a range higher than atmospheric pressure due to the action of the air valve 14. The molten thermal ink is injected toward the recording member 9 by the air pressure, cooled and solidified, and recorded as dots. Here, the heater 3 may be energized by continuous energization during recording, or pulsed energization in synchronization with the heating element 20 energization pulse. Immediately after the molten thermal ink is ejected, the heating element 2 is still in a high temperature state, so another molten thermal ink flows, blocks the through hole, and radiates heat and solidifies. FIG. 4 shows this operation in a simplified manner with time as the horizontal axis for ease of understanding.

In FIG. 4, when a voltage of waveform a is applied from the pulse generator 17 to the electromagnetic solenoid 13, the air pressure in the airtight container 1 becomes as shown by waveform C. The dotted line represents the air pressure threshold at which molten thermal ink can be ejected. When a pulse voltage of waveform (1) is supplied to the heating element 2, the temperature of the heating element 2 and the temperature of the thermal ink in contact with it are as shown in the waveform f<7c.The dotted line e indicates the temperature of the heating element 2.
represents the threshold temperature at which thermal ink can be melted in contact with

The conditions under which thermal ink can be ejected from the heating element using air pressure are that the air pressure is above the dotted line and the temperature of the thermal ink is above the dotted line e.
That is, the waveform is as shown in g.

The conditions under which the thermal ink can be supplied to the heating element 2 are that the air pressure is below the dotted line and the temperature of the thermal ink is above the dotted line e, that is, the ink becomes wavy.

In this way, the thermal ink is ejected in the waveform g and is supplied in the waveform. Unless a pulse voltage is supplied to the heating element 2 with waveform d, thermal ink will not be ejected or supplied. In this way, characters, images, etc. are usually recorded in a dot configuration by selectively supplying pulse voltage to a plurality of heating elements 2 according to the image signal. Here, the heater 3 can also be constructed of two heaters provided with a narrow gap, such as the heater 6 shown in FIG. 2, for example. In this case, the supply of molten thermal ink becomes smoother due to capillary action.

Further, the heating element 2 and the heater 3 shown in FIG. 1 may be constructed of the same material as the heating element 15 shown in FIG. 3.

Further, by reheating the recording member 9 with an infrared lamp 11 as shown in FIG. 1, the recording state becomes more reliable.

As described above, it is possible to realize a small, lightweight image recording device with low maintenance costs (without using consumables such as thermal ink film). There are effects such as being easily realized by using .

[Brief explanation of the drawing]

FIG. 1(A) is a model diagram showing the overall configuration of an embodiment of the present invention, FIG. 1(B) is a top view showing the relationship between the heating element, the recording paper, and the platen, and FIG. 2 is the heating element, FIG. 3 is a perspective view of another embodiment of the heater portion, and FIG. 3 is an exploded view of an embodiment of the heat generating heater element. FIG. 4 is a diagram showing changes in air pressure and the timing of injection and supply of molten ink, with the horizontal axis as the time axis. 1...Airtight container, 2...Heating element, 6
...Heater, 8...Thermal ink, 1
2...Diaphragm, 13...Electromagnetic solenoid, 14...Air valve, 17...Pulse generator.

Claims (1)

[Claims] In an image recording device that selectively melts thermal ink using a heating element and injects it using air pressure to record on a recording member,
The heat-sensitive ink and the heat-generating element include means for supplying the heat-sensitive ink to the heat-generating element, means for generating the air pressure, and an airtight container for causing the air pressure to act on the heat-generating element, and the air pressure is applied to the heat-generating element. An image recording device characterized by air pressure that changes periodically in synchronization with the heat generation of an element.