JPH0647287B2 - 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 Problems In a print-disabled state in which the recording body is lost, a paper empty signal from the detection unit that detects the presence or absence of the recording body closes the working surface where the tip of the recording electrode is exposed with a cap. .

Action When printing is disabled, the cap automatically closes the working surface where the tip of the recording electrode is exposed to prevent ink from evaporating from the tip, and this state continues until the recording medium is set. Therefore, the tip portion of the recording electrode can always be kept constant, and a stable printing state can be obtained.

Embodiment A first embodiment of the present invention will be described with reference to FIGS. 1 to 7. 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.

Then, inside the case 9 of the printer head 4, an ink chamber 11 for storing the ink 10 is formed, and inside the ink chamber 11, a recording electrode 12 having conductivity and ink impregnation property is provided. 13 is provided so as to be exposed to the outside. Then, one surface of the case 9 is a cylindrical surface 14 as an operating surface, and the tip portion 13 of the recording electrode 12 is located substantially in the center of a recess 15 formed in the cylindrical surface 14. At the lower end of the cylindrical surface 14, a stopper 16 having a surface intersecting the arc is provided.

Between the recording electrode 12 and the counter electrode 5 as described above,
Two power sources 18, 19 with a high voltage switch 17 interposed
Are connected, and the connection midpoints of these power supplies 18 and 19 are grounded. Further, the high voltage switch 17 is connected to a print control circuit 20 for generating a signal for opening and closing the high voltage switch 17 according to an image signal.

In addition, the support shaft 21 is positioned at the center of curvature of the cylindrical surface 14.
A cap 23 having a closing surface 22 that hermetically contacts the cylindrical surface 14 is rotatably provided on the support shaft 21. The support shafts 2 on both sides of the cap 23
A gear 25 is formed in the fitting portion with the gear 1 so as to be located inward of the side wall 24 of the cap 23.

Next, an internal hollow stage 26 is provided on the upper surface of the carrier 3, and a motor 27 serving as a drive unit for the cap 23 is provided in the stage 26. A drive gear 28 is fixed to the drive shaft of the motor 27, and the drive gear 28 is meshed with an intermediate gear 29 axially mounted on the upper portion of the stage 26. The intermediate gear 29 is meshed with the gear 25 of the cap 23.

Therefore, the printer body 1 is provided with a detection unit 30 for detecting the presence or absence of the recording paper 6, and the detection unit 30 is connected to the motor 27 via a drive unit control circuit 31.

Further, the drive unit control circuit 31 includes a waiting time determination circuit 3
2 is connected. The waiting time determination circuit 32 detects the input waiting time of the print signal and is connected to the print signal circuit 33.

In such a structure, the cap 23 is in close contact with the cylindrical surface 14 of the printer head 4 to shield the recording electrode 12 from the outside air when not printing, as shown in FIG. Therefore, the water content of the ink 10 with which the recording electrode 12 is impregnated does not dry, and the state of the tip portion 13 of the recording electrode 12 does not change. Therefore, the printing condition is stable even if it is not used for a long period of time.

Next, when a print command is issued, the motor 27 is energized, and the cap 2 is passed through the drive gear 28, the intermediate gear 29, and the gear 25.
3 is rotated as shown in FIG. As a result, the cylindrical surface 14 closed by the cap 23 is opened,
The tip portion 13 of the recording electrode 12 is exposed to the outside air. This state is a printable state, the high voltage switch 17 is turned on / off by a signal from the print control circuit 20, and an electric field sufficient to cause the ink 10 to fly is applied between the recording electrode 12 and the counter electrode 5, and the ink 10 Adhere 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.

Then, when the printing operation is performed or when the printing is started and the detection unit 30 detects the absence of the recording paper 6 and generates the paper empty signal, the signal is given to the drive unit control circuit 31. Drive the drive unit 27. As a result, the cap 2 is changed from the state shown in FIG. 2 to the state shown in FIG.
3 is moved back and the cylindrical surface 14 where the recording electrode 12 is exposed
To block. As a result, the tip portion 13 of the recording electrode 12 is shielded from the outside air, and the evaporation of the ink 10 is prevented. The closed state of the cap 23 continues until the recording paper 6 is set again. When the recording paper 6 is set, the recording electrode 1
Since the tip portion 13 of the second sheet 2 is covered with the cap 23, there is no possibility that the recording paper 6 comes into contact with the tip portion 13 and the operability thereof is extremely high.

The operation when the power of the apparatus is turned on will be described with reference to FIG. First, when the power is turned on, the motor 27 is energized to open the cap 23. Then, if there is a print signal, it prints, and if there is no print signal, it waits, but in each case, check whether a preset α time has elapsed from the last print, and print the signal before the α time elapses. If there is, the normal operation is performed, but if there is no next print signal even after the passage of the α time, the waiting time determination circuit 32 energizes the motor 27 to drive the cap 23 in the closing direction. As a result, the cylindrical surface 14 is closed, the power is turned off at the end of printing, and when the printing is continued, the print signal is supplied from the print signal circuit 33, so that the motor 27 is energized again to open the cap 23.

In this way, when left without printing, the tip portion 13 of the recording electrode 12 is automatically closed by the cap 23, the evaporation of the ink 10 is prevented, and the tip portion 13 is maintained in a constant state. To do.

Next, a second embodiment of the present invention will be described with reference to FIGS. 8 and 9. The same parts as those in the above-mentioned embodiment are designated by the same reference numerals and the description thereof will be omitted. First, the carrier 3 is provided with a guide support shaft 34 projecting toward the counter electrode 5, and a printer head 35 and a tension spring 36 are provided on the guide support shaft 34.
Are reciprocally attached while being biased in a direction away from the counter electrode 5. A cap 37 is attached to the upper end of the carrier 3 so as to be rotatable about a shaft 38. The cap 37 has a tension spring 39.
Is urged to cover the front surface of the printer head 35 as an operating surface. An electromagnet (not shown) is embedded in the cap 37 and the front surface of the printer head 35, and is used so as to be airtightly joined in a closed state by using packing and the like. Further, below the carrier 3, a solenoid 40 as a drive unit is attached, and this solenoid 40 is provided with a movable iron core 41. An end portion of the movable iron core 41 is bent in a V shape to have a lower end. A slide hole 44 in the middle of a lever 43 rotatably held by a shaft 42 is engaged. A slide hole 45 is also formed at the upper end of the lever 43.
The printer head 35 is connected to the printer 5.

In such a configuration, the recording electrode 12 itself has an ink impregnating property, and thus the ink 10 is sufficiently supplied to the tip portion 13. However, since the ink 10 is held by the recording electrode 12, it does not drop. Then, the solenoid 40 is energized prior to printing. As a result, the movable iron core 41 is
It moves from the position shown in the figure to the position shown in FIG. Therefore, the printer head 35 pushes and rotates the cap 37, so that the tip portion 13 of the recording electrode 12 is opened. When the printing state ends, the energization of the solenoid 40 is cut off, the printer head 35 returns by the force of the tension spring 36, and the cap 37 by the force of the tension spring 39.
The front end 13 of the ink is covered to effectively prevent the ink 10 from drying when not in use.

The operation of the solenoid 40 is subject to the above-mentioned control shown in FIGS. 6 and 7, and the cap 37 records when the recording paper 6 is exhausted or when a certain time has elapsed since the last printing. It operates so as to close the tip portion 13 of the electrode 12.

Although the cap is rotated in each of the above-described embodiments, the operating surface is closed by the cap in various forms, and the cap is directly or indirectly opened / closed by the drive unit. Various types of mechanisms can be used.

The same applies to the recording electrode not only for the stationary type but also for the movable type in which the distance between the opposite electrodes can be varied between the opposite electrodes.

The present invention is provided with a cap for opening and closing the operating surface of the printer head in which the tips of the recording electrodes are exposed as described above, and when the recording medium is exhausted, the operating surface is output by the paper empty signal from the detecting portion. Since I tried to block it with a cap,
It is possible to eliminate the state where the tip of the recording electrode is exposed to the outside air after the recording body is gone, so that there is no fear that the printing condition will deteriorate even if it is left as it is after the recording body is gone. It is possible to maintain a stable printing state.

[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 a printing state, FIG. 3 is a vertical side view showing a printing principle, and FIG. 4 is a perspective view of a printer main body. FIG. 5 is a perspective view of the printer head, FIG. 6 is a block diagram, FIG. 7 is a flow chart, FIG. 8 is a vertical sectional side view showing a second embodiment of the present invention, and FIG. It is a vertical side view. 4 ... Printer head, 5 ... Counter electrode, 6 ... Recording paper
(Recording body) 10 ... Ink, 12 ... Recording electrode, 13 ...
... Tip part, 14 ... Cylindrical surface (operating surface), 23 ... Cap, 27 ... Motor (driving part), 30 ... Detection part, 35 ...
… Printer head, 37… Cap, 40… Solenoid (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 body to form an image, a printer head for holding the recording electrode is formed, A cap that opens and closes an operating surface of the printer head where the tip of the recording electrode is exposed is connected to a driving unit, and the cap is operated by a paper empty signal from a detection unit that detects the presence or absence of a recording medium. The printing apparatus is characterized in that the drive unit is driven so as to close the printer.