JPS6058697B2 - non-impact dot printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a so-called dot printer, which selects specific points from a large number of dots (dots) arranged vertically and horizontally in a grid pattern within a certain area, and prints out a specific character or character. The dots are printed or printed by printing the dots selected in this manner on the paper surface to represent a figure.In the present invention, as a means of printing these dots, small bubbles are formed and floated in the ink liquid. This method utilizes the phenomenon in which micro droplets of ink are released as the bubbles burst.

Conventional non-impact dot printers have already been proposed, such as those that use a combination of thermal paper and a heating point with an array of minute heating elements, printing machines that use discharge breakdown like facsimile machines, and inkjet printing devices. However, these methods have drawbacks such as requiring special thermal copying paper, using high voltage, or having a very complicated structure.

In order to create a dot printer that does not exhibit such drawbacks, the inventor focused on the phenomenon in which droplets are released from the liquid surface when a bubble bursts, and created a dot printer that generates small bubbles at a specific position on the liquid surface in a certain area and We investigated the possibility of using it as a dot printer. The droplet release phenomenon that occurs when bubbles burst is, for example, when small carbon dioxide gas bubbles rise to the surface of a carbonated drink and burst, or when water is heated to a temperature of 40 to 60 degrees Celsius, and bubbles float up and burst. Under appropriate conditions, only one droplet is ejected vertically onto the liquid surface upon bursting of one bubble. The present inventor has long discovered that when small bubbles, such as those seen in a carbonated drink poured into a glass, rise from the liquid and burst at the liquid surface, only one relatively coarse droplet is produced perpendicular to the liquid surface. As a result, when the surface tension of the liquid and the bubble diameter meet certain conditions, a relatively small bubble (for example, about O, 3Trrn & ~2Tfrmφ) When a bubble rises from the liquid and bursts on the liquid surface, only one droplet with a size corresponding to the diameter of the bubble (approximately 1/m of the bubble diameter) is thrown up perpendicularly to the liquid surface. I learned that it exhibits a special phenomenon called To explain this phenomenon more clearly using diagrams, attached Figure 1 shows the state of droplet ejection using an enlarged cross-sectional view. When the bubble bursts, the shock wave caused by the instantaneous rupture of the surface tension propagates along the inner surface of the bubble and concentrates in the center, causing droplets to protrude from this area. If the conditions are met, only one droplet will be thrown up perpendicular to the liquid surface.

The inventor of the present invention predicted that applying this phenomenon to a dot printer would bring about various advantages without the drawbacks mentioned above, and investigated the possibility.

As a result, the present inventor arranged a large number of capillary tubes with their tip openings lined up as printing points directly below the printing surface, and sent small bubbles into the ink liquid from within the capillary tubes in a pulsed manner to place them at their tips. Printing or printing that is configured to print dots by ejecting small droplets of ink by bursting bubbles, and selectively actuating those of these capillaries at points corresponding to specific characters or figures. devised a non-impact dot printer for According to the present invention, there is no noise, water-based ink can be used, so there is no danger of odor or ignition, and since no high voltage is required, the equipment is safe and simple, and there is no need for special printing paper. Inventive step can be achieved.

Hereinafter, the present invention will be explained in more detail with reference to the accompanying drawings.

FIG. 1 is an explanatory diagram illustrating the situation in which droplets are released when a bubble breaks as described above, and FIG. 2 is a partially divided perspective view illustrating the outline of a non-impact type dot printer according to the present invention. FIGS. 3 and 4 are perspective views illustrating one specific example of means for selecting a specific position from among a large number of thin tubes arranged in the printing section.

In Fig. 2, reference numeral 2 indicates a large number of small sections in which a large number of thin tubes 1 are regularly arranged in a lattice pattern as shown in the figure. The ink liquid containing small bubbles is selectively fed into this thin tube by a valve control device 7 located below.

The printing section is filled with ink liquid to such an extent that the open tips of these thin tubes are slightly submerged below the ink liquid level.Maintaining this liquid level from a constant level is achieved by a known liquid level J controller 4. At the same time, it serves to replenish ink liquid from the ink liquid tank 5. It is preferable that the distance from the liquid level to the opening is approximately the same depth as the diameter of the generated bubbles. When the amount of ink remaining in the ink liquid tank 5 becomes less than a certain amount, the remaining amount detection device 4 device 6 issues an alarm. A large number of printing papers 14 are stored in the paper bag 12, and when printing starts, they are automatically taken out one by one and transferred to the paper feed roller 13 and suction conveyor belt 1.
6, it is sent to the position of the printing section 2. At this time, if the leading edge of the paper passes the point of the paper feed monitoring means 10 (for example, a known photoelectric relay switch, etc.), the controller box 9
The relay inside is activated and the rotation of the paper feed roller 13 is stopped. At this time, the paper is attracted to the lower surface of the belt 16 of the conveyance means by an air suction suction conveyance means disposed above the printing section, and is maintained at a constant distance above the ink liquid surface, and the paper is printed as shown in the figure. It is sent out to the position of section 2. This suction lifting and conveying means includes an air box 15 in which a large number of suction ports are arranged, a conveying belt 16 that moves around this box, and a pulse motor 11 for driving this belt.
The drive of this pulse motor is controlled by a control means in a control box. When one horizontal line of dot printing on the printing paper is completed, the pulse motor 11 is operated by the relay means housed in the control box 9 for one line of characters, and the belts 16 and 16a are activated.
, thereby advancing the paper to the position of the next line, and then printing of the next line based on input signal 1 is started again by a command signal from the control box.

The case shown is a specific example suitable as a dot printing device for typesetting printing, but of course it can also be used for copying printed matter or figures, and in that case, the printing section should be divided into subdivisions. It is convenient to arrange the foam dots (print dots) over the entire surface, and to selectively activate the print dots by signals based on light from points corresponding to these dots on the original drawing. In this case, it is also preferable to arrange the print dots in one row horizontally so that the feeding speed of the original image and the feeding speed of the printing paper are synchronized. As shown in the figure, the delivery belt 16a is disposed surrounding the heating box 17, and is designed to dry the printed paper by heating it with a heater 18 and send it out.

Of course, other means can also be used for this drying, such as the use of blotting paper rollers. The paper printed in this way is placed on the receiving plate 1.
9 is discharged on top. A dot printer based on an input signal 1 inputs this signal into a control switch device 8 which actuates a valve controller 7 to inject a small amount into a capillary at a printing point corresponding to a particular set of columns and rows of dots. This is carried out by sending out the bubbles to make them float, or by squeezing out small bubbles in a pulsed manner from the tip of this thin tube.

At this time, the small bubbles that have reached the liquid surface burst and micro droplets of ink drop out, hitting the paper or other printed image and printing dots. It is convenient to have a structure in which air can be forced into each thin tube through a fine hole nozzle, thereby sending fine air bubbles into the tube and pushing up the ink liquid. FIGS. 3 and 4 show examples of air outlet switching valve controllers suitable for this purpose. 20 is a vertical opening/closing valve body;
Reference numeral 21 denotes a transverse opening/closing valve body, and by sliding the valve stem 22 using the electromagnetic actuating means 23, all the gas passages in one row are opened and closed at the same time, and in this way, the nozzles to the thin tubes in which row and row are opened. It is determined whether

This specific array has the advantage that it requires extremely simple circuit means for printing from a print dot selection signal by scanning. It is convenient for the scanning switch control section to be a switching means using, for example, a microscopic switching element configured to turn on and off under a stepwise gate bias voltage, and this is used in combination with a converter.

[Brief explanation of the drawing]

FIG. 1 is an explanatory view of changes over time to explain the state of droplet discharge accompanying bubble breakage, FIG. FIG. 4 is an explanatory diagram showing an example of the structure of the valve control section. 1... Thin tube, 2... Imprinting part, 3...
... Ink liquid, 4 ... Liquid supply and liquid level controller, 5 ... Ink liquid tank, 6 ...
・Residual liquid amount detection means, 7... Valve control section, 8...
...Converter, 9...Controller, 10.
... Paper feed monitoring means, 11 ... Pulse motor, 12 ... Print paper back, 13 ... Paper feed roller, 14 ... Print paper , 15...
Suction air box, 16, 16a... Conveyor belt, 17... Heating box, 18...
Heater, 19... Reception plate, 20... Column on-off valve body, 21... Transverse on-off valve body, 22... Valve stem, 2
3... Electromagnetic actuation means.

Claims (1)

[Claims] 1. A type of non-impact printing that selects points corresponding to specific characters or figures from among a large number of printing points arranged in a certain area and prints these points on the printing surface of paper, etc. In a dot printer, the printing means consists of a number of thin tubes that form microbubbles at the tip of the ink liquid corresponding to each printing point, and air is pulsed into the tubes in response to an input signal. The non-impact dot printer is provided with a valve control device for feeding the ink, and the tip of the thin tube is arranged near the ink liquid surface so as to face the ink liquid surface.