JPH078572B2 - Electric field printer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a printer using an electric field curtain force.

(Prior Art and Problems to be Solved by the Invention) As a character image information output device, conventionally, an impact method (wire dot, shuttle method), an electrostatic recording method,
Printers such as a thermal recording system, an inkjet system, and a laser beam electrophotographic system have been put into practical use. Further, output devices are required to be smaller, lighter, color, maintenance-free, lower cost, lower noise, high speed, and high resolution. Inkjet printers are output devices that best meet the requirements for downsizing, weight reduction, colorization, cost reduction, and speedup.

Inkjet printers include an on-demand system (pulse pressure system) and a bubble jet system.
The on-demand method is a method in which particles are ejected from a nozzle by a change in pressure wave by a piezoelectric element and recording is performed without deflection. Further, the bubble jet method is a method in which a bubble is generated by heat generated by a heating resistance element embedded in a nozzle, and ink particles are ejected from the nozzle by utilizing a force of spreading the bubble.

It is an object of the present invention to provide a new jet generation type printer that can meet the demands of smaller size and lighter weight than the conventional inkjet generation type.

Incidentally, the present invention is a novel jet generation method using an electric field curtain force, and an AC electric field is applied to two electrodes to cause the electric field curtain force to act on ink or the like for recording, but in contrast to this, a slit is used. In the jet recording method (refer to the 14th Image Engineering Conference Pre-stripe Collection), oil-based ink is filled in the slit-shaped openings in which the recording electrodes are arranged corresponding to the pixels, and the recording electrodes and the counter electrode on the back of the recording paper are filled. By applying a voltage (direct current) pulse between and, the ink near the tip of the recording electrode is charged, and the ink is ejected toward the recording paper by electrostatic force to perform recording. Further, the electric field curtain force is used to separate the toner from the polar carrier in the developing mechanism of the electrophotographic copying machine (see Japanese Patent Laid-Open No. 60-51558).

(Means for Solving the Problems) An electric field curtain printer according to the present invention is an electric field curtain printer that deposits a printing material on a recording medium in response to an image signal, and supplies a printing material that can be charged. Regarding the supply means, the nozzle means having an opening for ejecting the supplied printing material, the first electrode arranged in contact with the printing material in the vicinity of the opening of the nozzle means, and the ejection direction of the printing material An alternating electric field is generated between the second electrode arranged at a position facing the first electrode and the first electrode and the second electrode in response to the image signal, and the electric field near the opening is generated. And a power source for ejecting the printing material by applying an electric field curtain force to the printing material.

(Operation) The printing material near the opening is in contact with the first electrode,
This gives an electric charge. When the power supply applies an alternating voltage of sufficient height between the first and second electrodes, the power supply functions as a charging means and charges the printing material in the vicinity of the opening of the nozzle means. Further, when the voltage applied between the first and second electrodes of the power source is low, the electric charge is charged by the contact between the electrode material and the printing material, and the electric field is vibrated by the alternating electric field to repeat the triboelectric charging. Finally, it is charged to a sufficient level. The printing material thus charged is subjected to the electric field curtain force by the alternating electric field applied between the first electrode and the second electrode, and is ejected from the opening.

(Examples) Examples of the present invention will be described below with reference to the accompanying drawings.

The principle of generation of the electric field curtain force will be described with reference to FIGS. 2 (a) and 2 (b). Two rod electrodes 1 and 2 are arranged in parallel, and an alternating power source 3 is connected between them. When an alternating electric field (line of electric force is shown by a broken line) is generated by the alternating power source 3, both electrodes are
For charged particles (regardless of polarity) 4 near 1,2,
As shown in Fig. 2 (a), the gradient force parallel to the electric field gradient The direction perpendicular to this and away from the plane passing through both electrodes 1 and 2 Works. External force The charged particles 4 act in a direction away from the electrodes 1 and 2.
(The charged particles on the lower side of the plane passing through both electrodes 1 and 2 move away to the lower side.) Since the direction of the lines of electric force alternates with the alternating voltage, the second
As shown in FIG. 6B, the charged particles move in a zigzag manner, and fly as a whole by receiving an electric field curtain force in the direction indicated by a thick arrow.

1 (a) and 1 (b) schematically show a recording head portion of an inkjet printer according to the present invention. Orifice 11
An insulating ink fountain 12 having a nozzle 11 provided with a is filled with high resistance ink or charged ink 13 in which precharged charged color particles are dispersed. Two electrodes 14 and 15 are provided in the vicinity of the orifice 11a on the inner wall of the nozzle 11 so as to contact the ink 13 and face each other with respect to the center line of the nozzle 11. A low frequency power supply 16 is connected to one electrode 14, and the other electrode 15 is grounded via a switch 17.

Now, when the switch 17 is open, the alternating electric field is ink 13
Does not work. The ink between the orifice 11a and the pair of electrodes 14 and 15 has a pushing force (gravitational force) that pushes the ink 13 toward the orifice 11a. And the surface tension that pushes back the ink 13 against it. And work. Both Ink 13 and the orifice
Not pushed out from 11a.

Next, when the switch 17 is closed by the jet control circuit 21 in response to the image signal of the memory 20, the electric field acts on the charged color particles in the ink 13, and the orifice 11a and the electrode pair 1 are formed.
The ink between 4,15 is the electric field curtain force shown in Fig. 2 (b). Then, the particles jump out from the orifice 11a, which is the open end, into particles and adhere to the plain paper 18. The electric field curtain force acts on the ink on the left side of the electrode pair 14, 15 on the left side,
Push 13 slightly to the left.

Dots with a diameter of about 50 μm can be formed by narrowing the nozzle diameter and adjusting the ink viscosity.

In the above example, the color particles (pigments) are charged in advance under a high electric field by a charging unit (not shown). However, if the voltage applied to the electrodes 14 and 15 is sufficiently high, the color particles near the electrodes 14 and 15 are charged by this voltage even if the color particles are not charged in advance. Then, the electric field curtain force acts on the charged color particles, and ink is ejected between the electrodes 14 and 15 and the orifice 11a as in the above example. Even when the voltage is low, only the contact charge generated by the contact between the electrode material and the color particles or ink triggers, which is vibrated many times by the alternating electric field and repeated triboelectric charging, resulting in a large electric field. Generates curtain power and gushes.

By the way, in the nozzle shown in FIGS. 1 (a) and 1 (b),
It takes time for the rear space ink to be replenished in the empty space 13a (see FIG. 3 (b)) after the ink has been ejected due to gravity and capillary action, so there is a limit in increasing the frequency response of switching. .

Therefore, as shown in FIGS. 3A and 3B, two alternating power supply side electrodes 14a, 14b and two ground side electrodes 15a, 15b are provided. That is, the inner wall of the nozzle 11 is provided in the vicinity of the orifice 11a so as to contact the ink 13, and the electrodes 14a and 1a are provided.
5a and 5a, and electrodes 14b and 15b with an appropriate gap.
And face each other.

An electric field curtain force acts on the ink near the electrodes 14a, 14b, 15a, 15b as shown in FIG. 3 (c). Electrode pair
The ink between 14a, 15a and 14b, 15b is balanced by the electric field curtain forces acting in the opposite directions, and the electric field curtain force does not substantially act. On the other hand, the electric field curtain force acts in the right direction on the ink on the right side of the electrode pair 14a, 15a, and the electric field curtain force acts on the left side in the ink on the left side of the electrode pair 14b, 15b.

When the switch 17 is opened (Fig. 3 (a)), the ink 13 is discharged in the same manner as in Fig. 1 (a). The ink 13 is not pushed out of the orifice 11a.

Next, when the switch 17 is closed (Fig. 3 (b)), the electrode pair
The ink between 14a and 15a and the orifice 11a is ejected as in the case of FIG. 1 (b). On the other hand, electrode pair 14b, 15b
An electric field curtain force acts on the ink on the left side of the ink in the left direction to form a cavity 13b. Furthermore, both electrodes 14a, 15a and 14b, 15
Since the electric field curtain force does not substantially act on the ink 13c between it and b, the ink 13c stays at that position and becomes the replenishing ink for the pulse signal for generating the next ink particle.
After the flying ink particles 19 fly out, the cavity 13a is immediately filled with the replenishment ink 13c by the action of gravity and the capillary phenomenon. Therefore, the flight response of this ink nozzle is improved. Also, the dot diameter can be reduced.

FIG. 4 schematically shows a multi-line head in which n minute nozzles are arranged in parallel corresponding to pixels. An insulating nozzle head 41 having n ink grooves and an upper plate 42 are combined to form n ink nozzles. Nozzle head
Approximately 50 μm on the bottom of each groove of 41 rectangular cross section
Width × about 10 μm thick gold electrodes 43a, 43b, ... are provided, and a switch 44a for applying a pulse signal (image signal) is further provided.
Connect to 44b, ... Correspondingly, on the lower side of the upper plate 42,
Similarly, gold electrodes 45a, 45b, ... Are provided and connected to the AC power supply 46. When the switches 44a, 44b, ... Are opened and closed according to the image signal, ink particles are ejected only from the nozzles with the switches closed.

(Effect of the Invention) According to the present invention, it is possible to provide a novel printer that ejects a printing material by an electric field curtain force. This printer can be downsized as compared with a conventional printer. In addition, the head has a long life as compared with the conventional printer because it does not receive physical stress only by applying the alternating electric field.

[Brief description of drawings]

FIGS. 1A and 1B are diagrams for explaining ejection of ink particles by the electric field curtain force. 2 (a) and 2 (b) are diagrams for explaining the principle of generation of the electric field curtain force. 3 (a) to 3 (c) are diagrams for explaining ink jet generation in which two pairs of electrodes are arranged. FIG. 4 is a diagram of a multi-head. 11 …… Nozzle, 12 …… Ink fountain, 13 …… Ink, 14,15; 14a, 14b, 15a, 15b …… Electrode, 16 …… Alternating power supply.

Claims (1)

[Claims] 1. An electric field curtain printer for depositing a printing material on a recording medium in response to an image signal, comprising: a supply means for supplying a chargeable printing material; and an opening for ejecting the supplied printing material. Nozzle means having a first electrode, a first electrode arranged in contact with the printing material in the vicinity of the opening of the nozzle means, and a first electrode arranged at a position facing the first electrode in the jetting direction of the printing material. By generating an alternating electric field between the second electrode and the first electrode and the second electrode corresponding to the image signal, and applying an electric field curtain force to the printing material near the opening, An electric field curtain printer, comprising: a power supply for ejecting printing material.