JPH02190339A - Non-contact-type recording apparatus - Google Patents

Abstract

PURPOSE:To obtain a recording apparatus stable with regard to circumferential conditions and with good responding property by flowing a gas the temperature of which is controlled, and using a recording medium having the temperature and viscosity characteristics corresponding to said temperature. CONSTITUTION:Jetting is directed downwards. A paper 16 is moved in a horizontal direction at the lower surface of the apparatus. A gas flow 13 such as the air flow is pressurized and supplied by a pressurizing pump 14. At this time, a temperature sensors, e.g. a thermocouple or a thermistor provided in the halfway of the supply route detects the temperature of the pressurized gas flow. The temperature of the gas flow is controlled to be constant by a gas heater provided in the halfway of the pressurized gas flow or at an entrance or exit of the pressurizing pump via a control circuit 15. The temperature is controlled to be 30-80 deg.C. Accordingly, a recording medium at the nozzle or at the exit of a slit can be made stable even when the circumferential temperature is changed to the solidification temperature or the temperature whereat the recording medium is made highly viscose.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a non-contact type recording device, and more particularly to a recording device for a recording engine such as a printer or a fax machine that uses a phase-changeable recording medium such as wax. .

Prior art related to the present invention includes U.S. Patent No. 37907
03 Mei III, JP-A-63-57248, and JP-A-63-122553. U.S. Pat. No. 3,790,703 discloses an orifice and a switching heating means provided near the orifice, and a configuration in which the ejected ink is conveyed to the printing surface by an air flow. does not specifically indicate the setting of the air temperature that would cause the ink to solidify at the tip of the orifice and cause a clogging condition. Further, the structure is not such that the pressurized gas acts sufficiently as a force for ejecting ink. Furthermore, not only is the ink ejected from the orifice scattered and the resolution not improved, but there is no mention of the relationship between the temperature and viscosity characteristics of the recording medium and the temperature of the pressurized gas, and for this reason, a large heating power is required. The printing characteristics change greatly depending on the environmental temperature conditions, and there are problems with reliability. JP-A-63-57248 discloses that the surface tension and viscosity of the ink is lowered by a heating means provided near the nozzle opening, making it easier to eject the ink due to electrostatic suction force. JP-A No. 63-122553, which does not utilize phase change ink, uses electrostatic force to eject ink, and while it is flying, it is carried by air to increase printing speed.

Although the structure of the multilayer is disclosed, the two publications mentioned above do not utilize phase change ink, but are improvements to the conventional electrostatic suction method, and utilize phase change as the ejection principle. However, there are still problems with image quality deterioration such as clogging when left unused, bleeding of ink adhering to the paper surface, and deformation of dot diameter.

Furthermore, high voltage switching is required, which poses problems in terms of integration and cost.

■--Blood This invention was made in view of the above-mentioned circumstances,
In the recording engine of copying machines, printers, etc., the purpose is to provide a recording device that specifically enables colorization and digital recording, and is also advantageous for plain paper recording. Since it is possible to form an image in a short time, the durability and reliability of the device are improved, and a small and compact recording device becomes possible. In addition, since it is an ink that utilizes phase change, it solves the problems of inkjet jets that use conventional water-based inks, such as drying out and clogging when left unused. The objective is to solve the reliability problem of 1 image quality degradation in principle. Further, a heating heater is provided only in the lower part of the ink area after injection is turned off, and the area of the heater exposed to air is made as small as possible to suppress heat loss during heating. Furthermore, it is an object of the present invention to provide a non-contact type recording device in which the ejected recording medium is sufficiently placed in the gas flow to obtain a high-resolution image without spreading the printed dots.

Pus - Issei.

In order to achieve the above object, the present invention provides a recording apparatus that performs printing using phase change of a recording medium.

A means for supplying a recording medium including a recording agent having a characteristic that ejection resistance during ejection decreases as temperature increases; a switchable thermal energy supply means provided near an ejection opening of the recording medium containing the recording agent; a gas flow supply means set at a temperature that solidifies or increases the viscosity of the recording medium by contact with the recording medium containing the agent at the discharge port; and a heating means that heats the recording medium up to the vicinity of the discharge port so that it can flow. Further, the switchable thermal energy supplying means is a resistance heating element that generates heat when energized, and includes on both sides or inside of the discharging nozzle or the tip of the slit of the recording medium containing the recording agent.
The heating element has a length equal to or greater than the nozzle diameter dimension or the slit width dimension, and furthermore, the ejection port tip of the recording medium containing the recording material to be ejected into the gas flow must be It is characterized by the fact that it is located on the inside.

Hereinafter, the present invention will be explained based on examples.

The phase-changeable recording medium used here is one whose main component is, for example, wax, which solidifies at least at room temperature and has a melting point above room temperature. Alternatively, any material that has the property of changing into a low viscosity liquid may be used.

For example, if wax is natural, plant-based waxes include candelilla wax, carnaube wax, rice wax, real wax, and jojoba oil.

Petroleum-based waxes include paraffin wax and microwax. In addition, if it is a synthetic wax, fatty acids,
Some are made of organic compounds such as acid amides, esters, and ketones. By mixing a plurality of these waxes in an appropriate ratio, a recording medium with arbitrary melting characteristics can be obtained, and by dissolving a recording material such as a coloring material using this wax as a main component, a phase-changing recording medium can be obtained.

As an example, the characteristics of a recording medium that exhibits viscosity changes with temperature are shown in Figure 5.At room temperature of 50 to 60 degrees Celsius, it becomes solid (area A), and at high temperatures of 90 degrees Celsius or higher, it becomes 500 cp.
The liquid becomes a low viscosity liquid (region C) with a sufficiently low resistance for ejection. In addition, the viscosity in the middle (region B) may be sufficient to supply to the discharge port, and it is sufficient to preheat to the second region B, or it may be heated and supplied to region C.

The recording principle using the above recording medium is described below.
The slit is made to flow continuously at a speed of over 1/s, which lowers the viscosity of the hot melt medium such as wax due to the negative pressure and frictional stress continuously generated at the recording medium ejection port on the wall. Alternatively, switching is performed to reduce the discharge resistance of the nozzle flow path, and discharge is performed.

Generally, the wall pressure Pa under gas flow is Pa=P−
1/2ρV" However, Pa is the pressure on the gas flow wall surface, P is the total pressure of the upper gas flow, p is the gas density, and ■ is the flow velocity of the gas flow. If the gas flow velocity V is fast, the value is smaller than P. If this Pa is a small value compared to the pressure applied to the recording medium tank, it will act as an ejection force.Furthermore, the frictional stress corresponding to the gas flow velocity gradient on the surface of the recording medium at the ejection port will also be Acts as ejection force and flight force.

On the other hand, the recording medium is supplied to the nozzle or slit portion as a flowable recording medium by preheating.

Next, the recording medium exposed to the gas flow at the nozzle or slit outlet becomes highly viscous or solidified to the point where the IA degree decreases and the recording medium cannot be ejected. This maintains the non-discharging state due to the discharge force of the gas flow.

Next, by energizing the heater near the nozzle or slit, the temperature is raised to a high temperature of, for example, 150°C to 400°C, resulting in a low viscosity recording medium of 100 CP or less, several tens of CP, and continues while the heater is energized. It will be ejected. It is accelerated and flies to the tip of the discharge port, and after adhering to the paper surface, it is cooled and solidified. Here, by flowing the gas flow at a flow rate of 10~Loom/s, a negative pressure value of several logs~several 100 g is easily generated on the recording medium at the ejection port.

FIG. 1 is an overall configuration diagram for explaining one embodiment of a non-contact recording device according to the present invention. In the figure, 11 is an ink tank, 12 is a head with a built-in driver, 13 is a gas flow supply port, and 14 is a Pressure pump.

15 is a temperature control section, and 17 is a preheater. The ink tank 11 is provided with a recording medium containing coloring materials such as cyan (C), magenta (M), yellow (Y), and black (B) dyes or pigments to enable color recording. The jet is directed downward, and a gas flow 13 such as air is pressurized and supplied by a pressurizing pump 14 so that the paper 16 is passed horizontally on the lower surface. At this time, there was a thermal lightning pair in the middle of the supply route.

The temperature of the pressurized gas flow is detected by a temperature sensor such as a thermistor, and controlled to a constant temperature via the control circuit 15 by a gas heater provided during pressurization or at the inlet or outlet of the pressurizing pump. This control temperature is 3
Set the temperature to about 0°C to 80°C. This objective is a temperature that solidifies or increases the viscosity of the recording medium at the exit of the nozzle or slit, and is stable even if the environmental temperature changes. Furthermore, if the gas flow is too low temperature, heater power is required to reduce the viscosity of the solidified recording medium, and the response becomes very slow. Therefore, in order to increase efficiency, it is desirable to set the temperature at a range from the upper limit temperature of the changing environmental temperature to 40° C. to 60° C. at which the recording medium solidifies or becomes highly viscous.

FIG. 2 is a specific configuration diagram of two recording head units according to the present invention. In the figure, 1 is a common liquid chamber, 2 is an on/off heater, and 3
4 is a gas flow, 4 is a heater for heating the base, 7 is a partition plate, 8 is a substrate, 9 is an upper plate, and 10 is a gap. Heater 4
There is a partition plate 7 between the upper plate 9 and the substrate 8, which has a gas flow outlet on the top and a recording medium containing the recording agent on the bottom. The partition plate 7 constitutes a slit of the medium discharge port.The partition plate 7 is located inside the tip of the substrate 8 and the upper plate 9, and is arranged so that the recording medium and the medium discharged into the gas flow are sufficiently separated from each other in the laminar flow of the gas flow. A heater 4 for heating the base is provided on the lower surface of the base substrate 8, and a preheater control circuit lowers the viscosity of the recording medium to a supplyable level and supplies it to the slit section.

FIG. 3 and FIG. 4 are diagrams showing the configuration of the partition plate and the heater. FIG. 3 shows the configuration of the heater 5 when, for example, the tip of the partition plate 7 is thick, or when ink is accumulated in front of the tip of the slit portion when ejection is turned off due to the flow of the gas flow 3. . Heaters 9 are provided in the front and rear regions of the slit tip. FIG. 4 shows a case where the tip of the partition plate 7 can be made thin, and when the ejection is turned off, ink flows up to the tip. Therefore, the heater 5 is provided on the lower surface from the tip to the common liquid chamber 1. It is being In other words, the heater 5 is heated up to the area where ink remains when the ejection is turned off.
A configuration in which there is no heater surface exposed to the gas flow 3 results in no heat loss. Furthermore, since the heater has a length longer than the slit width in the discharge direction, it has the effect of increasing the responsiveness of thermal melting.

Note that the common liquid chamber 1 of the base substrate 8 having the heater 5 is formed by machining a ceramic material. The heating resistor is generally a thin film formed by sputtering Ta-8iO□, which is a high resistivity material, or a Ta-N thin film. On top of this, 5i-N or S is used as an insulating protective film.
A thin film of iC or the like is formed to a thickness of several μm. Furthermore, a photosensitive dry film is laminated on top of this and patterned.
Four slits of 10 μm are formed for ejection of the recording medium, and Si
The head unit is made by laminating and bonding partition plates and top plates made of O or glass plates. Further, as the base substrate, a substrate having a heater can be obtained by repeating thin film lamination and etching on a silicon substrate by photolithography.

As is clear from the above explanation, according to the present invention, it is possible to adapt to environmental conditions by flowing a temperature-controlled gas flow and by using a recording medium with temperature and viscosity characteristics that respond to the temperature. On the other hand, it is possible to create a recording device that is stable and has good responsiveness.

Furthermore, due to the configuration of the heater area in the embodiment of the present invention,
This makes it possible to create a device that is efficient and responsive, and also allows for a device with high resolution and high speed.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram for explaining an embodiment of a non-contact recording device according to the present invention, FIG. 2 is a specific configuration diagram of a recording head section according to the present invention, and FIGS. 3 and 4 5 is a block diagram of a partition plate and a heater, and FIG. 5 is a diagram showing characteristics of viscosity change with respect to temperature of a recording medium. 1... Common liquid chamber, 2, 5... On/off heater
3... Gas flow, 4... Base heating heater, 6...
...Recording medium ejection port, 7...Partition plate, 8...Substrate, 9...Top plate, 10...Gap, 11...Ink tank, 12...Driver built-in head, 13...・
- Gas flow supply port, 14... Pressure pump, 15... Temperature control section, 16... Recording paper, 17... Preheater diagram

Claims (1)

[Claims] 1. In a recording device that performs printing by utilizing phase change of a recording medium, a means for supplying a recording medium including a recording agent whose ejection resistance during ejection decreases as the temperature rises, and a recording medium containing the recording agent. A switchable thermal energy supply means provided near the ejection port of the medium and a gas flow supply means set at a temperature that solidifies or increases the viscosity of the recording medium by contacting the recording medium containing the recording agent at the ejection port. 1. A non-contact recording device comprising: a heating means for heating a recording medium up to the vicinity of an ejection port so that the recording medium can flow.