JPH0647288B2 - Printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION INDUSTRIAL APPLICABILITY In the present invention, liquid ink is ejected by an electric field to form dots on a recording medium, and images of characters, figures, etc. are formed by combining the dots. The present invention relates to a printing device.

2. Description of the Related Art Conventionally, a so-called ink jet printer, which forms an image on a recording medium by ejecting liquid ink droplets from a nozzle, is
A number of inventions have been made and improvements have been made for the reasons that there is little noise during printing and that it is advantageous in running cost and the like when performing multicolor printing compared to other printing methods. However, measures against nozzle clogging due to evaporation of ink are not sufficient, and have become a practical problem.

In order to eliminate such clogging of nozzles, a method using liquid ink, which is different from the above-mentioned ink jet printer, has been considered.

First, as an example, as described in JP-A-56-170 and JP-A-56-4467,
Instead of nozzles that easily cause clogging, slit-shaped openings are formed, and an electric field is applied between opposing electrodes facing the openings to eject ink.

In this type, the structure for releasing the ink droplets from the slit-shaped opening is delicate and there is a problem that the stability is insufficient.

Another method is disclosed in Japanese Patent Laid-Open No. 54-2353.
As disclosed in Japanese Patent Laid-Open No. 4 and Japanese Patent Laid-Open No. 59-159355, the ink is guided to the tip of the needle-shaped member along the outer periphery thereof, and the ink is ejected by an electric field.

In this type, magnetic ink must be used to guide the ink to the tip of the needle-shaped member, and this magnetic ink has a degree of freedom in color selection due to the ground color of the magnetic powder contained therein. There is a drawback that there is no.

Problems to be Solved by the Invention In order to solve the drawbacks while using liquid ink while maintaining the features of the ink jet printer described above, clogging does not occur at the portion where ink is discharged. Is absolutely necessary.

Also, the use of magnetic ink as the liquid ink is not desirable in terms of its color, and it must be possible to print with ordinary ink.

Means for Solving the Problems A cap for opening and closing the surface where the tip of the recording electrode of the printer head is exposed is provided, and a recording electrode is provided so that it can move back and forth, and the electrode drive unit and the cap for driving this recording electrode are driven. It is provided so as to be synchronized with the cap drive unit.

Function A cap drive that moves the recording electrode forward and backward to effectively discharge electrostatic ink, and a cap that closes the tip of the recording electrode to prevent ink evaporation and that drives the cap open and close freely Since the cap drive section and the electrode drive section are provided so as to be synchronously interlocked with each other, the cap is opened and the recording electrode is advanced at the same time. In addition, the ink is effectively shielded from the outside air, and the ink is effectively prevented from evaporating to maintain a constant printing state for a long period of time.

Embodiment A first embodiment of the present invention will be described with reference to FIGS. 1 to 5. First, the printer main body 1 is provided with two guide shafts 2 (only one is shown in FIG. 1) horizontally on the front side thereof, and a carrier 3 is reciprocated left and right on the guide shaft 2. It is attached freely. A printer head 4 is mounted on the carrier 3. Further, a counter electrode 5 facing the printer head 4 is horizontally attached to the central portion of the printer body 1. A tractor 7 for feeding a recording paper 6 as a recording medium is provided at the back of the counter electrode 5. An operation knob 8 protruding outward is coupled to the tractor 7.

An ink chamber 11 for storing the ink 10 is formed inside the case 9 of the printer head 4, and a recording electrode 12 having conductivity and ink impregnating property is provided inside the ink chamber 11. 13 is exposed to the outside and is provided so as to be movable back and forth in the axial direction. One surface of the case 9 is a cylindrical surface 14, and the tip portion 13 of the recording electrode 12 is fitted in a sliding hole 15 located substantially at the center of the cylindrical surface 14. At the lower end of the cylindrical surface 14, a stopper 16 having a surface intersecting the arc is provided. An electromagnet 17 serving as an electrode driving unit is provided at the rear of the ink chamber 11. An armature 18 is provided so as to face the electrode stone 17, and the recording electrode 12 is integrally connected to the armature 18 via an insulator 19. Then, the armature 18 is urged by a spring 20 in a direction away from the electrode stone 17.

Between the recording electrode 12 and the counter electrode 5 as described above,
Two power sources 22 and 23 with a high voltage switch 21 interposed
Are connected, and the connection midpoints of these power supplies 22 and 23 are grounded. Further, the high voltage switch 21 is connected to a print control circuit 24 which generates a signal for opening and closing the high voltage switch 21 in response to an image signal.

Further, the support shaft 25 is located at the center of curvature of the cylindrical surface 14.
The support shaft 25 is rotatably provided with a cap 27 having a closing surface 26 that comes into contact with the cylindrical surface 14 in a sealed manner. The support shafts 2 on both sides of the cap 27
A gear 29 is formed at the fitting portion of the cap 5 so as to be located inward of the side wall 28 of the cap 27.

Then, an internal hollow stage 30 is provided on the upper surface of the carrier 3, and a motor 31 is provided in the stage 30.
Is provided. A drive gear 32 is fixed to a drive shaft of the motor 31, and the drive gear 32 is connected to the stage 3
It is meshed with an intermediate gear 33 which is axially attached to the upper part of 0. The intermediate gear 33 is meshed with the gear 29 of the cap 27.

In such a configuration, the recording electrode 12 is located inward of the cylindrical surface 14 when not printing, as shown in FIG. Further, as shown in FIG. 1, the cap 27 is in close contact with the cylindrical surface 14 of the printer head 4 to shield the recording electrode 12 from the outside air. Therefore, the water content of the ink 10 with which the recording electrode 12 is impregnated does not dry, and the tip portion 1 of the recording electrode 12 does not dry.
The state of 3 does not change. Therefore, the printing condition is stable even if it is not used for a long time.

Next, when a print command is issued, the motor 31 and the electromagnet 17 are energized synchronously, and the cap 27 is rotated through the drive gear 32, the intermediate gear 33, and the gear 29 as shown in FIG. 12 is projected from the cylindrical surface 14 as shown in FIG. This state is printable,
The high voltage switch 21 is turned on / off by a signal from the print control circuit 24, and the ink 1 is discharged between the recording electrode 12 and the counter electrode 5.
An electric field sufficient to cause 0 to fly is applied, and the ink 10 adheres to the recording paper 6 to form dots. A character or a figure is formed by a combination of dots formed by repeating such a process.

Next, a second embodiment of the present invention will be described based on FIGS. 7 and 8. The same parts as those in the above-mentioned embodiment are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, the surface of the printer head 4 from which the recording electrodes 12 protrude is formed into a flat surface, and a flat cap 27 is provided which reciprocates along this surface. The cap 27 is connected to a movable iron core 35 of a solenoid 34 which serves as a cap drive unit, and the movable iron core 35 is urged by a spring 36 in a direction in which the cap 27 moves in the closing direction.

The internal structure of the printer head 4 is the same as that shown in FIGS. 3 and 4, and the electromagnet 17 and the solenoid 34 are simultaneously energized by a print signal to open the cap 27 and the recording electrode 12. The protrusion is performed synchronously. In addition, the recording electrode 12 is inserted into the printer head 4 and the cap 27 is closed in synchronization therewith.

As described above, according to the present invention, the recording electrode is attached to the printer head so as to move forward and backward, and the cap for cutting off the tip of the recording electrode from the outside air is provided so as to be openable and closable, and the electrode driving unit and the cap for driving the recording electrode are provided. Since it is synchronized with the cap drive unit that drives the, the protruding position required for printing can be obtained even if the tip of the recording electrode is positioned deep inside the sliding hole or the like. It is possible to very effectively prevent the evaporation of ink from the tip of the recording electrode.

[Brief description of drawings]

FIG. 1 is a side view showing a first embodiment of the present invention, FIG. 2 is a side view of the printing state, FIG. 3 is a vertical side view showing the printing principle of a printer head, and FIG. FIG. 5 is a perspective view of the printer main body, FIG. 6 is a perspective view of a carrier portion thereof, FIG. 7 is a side view showing a second embodiment of the present invention, and FIG. It is a side view of a state. 4 ... Printer head, 5 ... Counter electrode, 6 ... Recording paper
(Recording body) 10 ... Ink, 12 ... Recording electrode, 13 ...
... Tip part, 17 ... Electromagnet (recording electrode drive part), 27 ...
Cap, 31 …… Motor (cap drive unit), 34 ……
Solenoid (cap drive unit)

Claims (1)

[Claims] 1. A recording electrode having conductivity and ink impregnation property is formed, and a counter electrode facing the recording electrode via a recording medium is provided, and an image signal is provided between the counter electrode and the recording electrode. In response to this, in a printing apparatus in which the ink impregnated in the recording electrode is electrostatically ejected from the recording electrode toward the recording medium to form an image, the printing device is driven by an electrode driving unit and is mounted so that it can move back and forth. A printer head for holding the recording electrodes is formed, and a cap for opening and closing the surface of the printer head where the tips of the recording electrodes are exposed to open and close the tips of the recording electrodes from the outside air is connected to a cap drive unit. A printing apparatus, wherein the cap drive unit and the electrode drive unit are provided so as to be synchronized with each other.