JPS626989B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to inkjet printers.

Conventionally, when the recording operation of an inkjet printer is stopped, a small amount of ink may adhere to the outer peripheral end surface of the nozzle hole of the inkjet nozzle. In addition, during a recording pause, the pipes that supply ink to the inkjet nozzle expand and contract due to temperature changes, which may cause ink to leak from the nozzle hole and adhere to the outer peripheral end surface of the nozzle hole. be. This adhered ink may deteriorate or
As new ink is repeatedly deposited, the deposited ink becomes highly viscous, and precipitates accumulate, clogging the nozzle holes, changing the direction of inkjet jetting, and Recording quality deteriorates due to changes in the characteristics of ink particle formation.

In order to solve this problem, it has been conventional practice to cover the nozzle hole of the inkjet nozzle with a lid to prevent the outer peripheral end surface of the nozzle hole from drying out. In such prior art, it is necessary to keep the vicinity of the nozzle hole airtight in order to reliably prevent the ink from drying, but this is difficult. Furthermore, it is not possible to prevent deterioration of the quality of the ink due to chemical changes in the ink.

A prior art technique for solving this problem is disclosed in Japanese Patent Application Laid-Open No. 49-51822. In this prior art, a hydraulic cylinder is provided near a nozzle that sprays an inkjet, and this hydraulic cylinder allows
The nozzle is configured to move a pad that wipes the nozzle aperture of the nozzle.

A new problem with such prior art is that the hydraulic cylinder is provided integrally with the nozzle, and therefore it is necessary to move the hydraulic cylinder integrally with the nozzle along the platen. This means that the weight of the object to be moved increases, resulting in a large inertial force, making it difficult to move back and forth at high speed, and placing a limit on printing speed.

In the prior art to solve this problem, for example, as in Utility Model Application Laid-open No. 53-60827, a cleaning material for wiping the nozzle hole of the nozzle is provided at the standby position of the nozzle that ejects the inkjet, and this cleaning material is circular. It has a columnar or belt shape and is configured to rotate the cleaning material. In other prior art, for example, as shown in Utility Model Application Laid-Open No. 55-13065, the purifying material fixed to the carrier is removed from the recording paper discharge roller at the standby position of the nozzle that ejects the inkjet. It is configured to convert rotational motion into linear motion and move back and forth to rub against the nozzle hole of the nozzle. Furthermore, other prior art is JP-A-55-
101460, ink is forcibly ejected from the nozzle hole of the nozzle at the standby position of the nozzle and collected in a collection tank, and then the nozzle hole is rubbed by a liquid absorbing member. .

In each of these prior art techniques, the structure for cleaning the nozzle hole of the nozzle by rubbing it is large and complicated, and the control for the rubbing operation is complicated. A problem arises.

SUMMARY OF THE INVENTION An object of the present invention is to provide an inkjet printer which can increase the recording speed as much as possible, and which can be made smaller by simplifying the structure.

The present invention comprises a platen 6 and a longitudinal guide means 1 arranged parallel to the platen 6.
1, 12, and the carriage 13, which is guided by a longitudinal guide means and can freely reciprocate between a first moving position 57 for waiting and a second moving position opposite to the waiting position 57. and means 1 for driving the carriage 13 to move between a first movement position 57 and a second movement position.
7, 18, 19, 20, a nozzle 3 fixed to the carriage 13 and ejecting the ink jet 5 toward the platen 6, and a first nozzle 3 attached to the carriage 13 along the direction of movement thereof.
The carriage 13 is moved between the first displacement position near the movement position 57 and the second displacement position near the second movement position.
such a movable body 22 is provided to be movable back and forth relative to the movable body 22 and allows the ink jet from the nozzle 3 to reach the platen 6 when in the first displacement position; When the body 22 is in the second displacement position, it abuts the nozzle hole 4 of the nozzle 3;
a pad 27 having the property of absorbing ink; first pressing means 31, 33 provided near the first movement position and pressing the moving body 22 to the second displacement position;
34, and a second pressing means 25 that is provided near the second movement position and presses the moving body 22 to the first displacement position, and at the start of the recording operation, the driving means 17, 18,
19 and 20 first move the carriage 13 back and forth from the first movement position 57 to the second movement position, whereby the second pressing means 25 moves the moving body 22 to the first displacement position, and then moves the carriage 13 to the second movement position. It moves backward to the first movement position 57, performs recording during the subsequent forward movement, and when the recording is finished, the driving means 17, 18, 19, 2
0 is an inkjet printer characterized in that the carriage 13 is returned to the first displacement position 57, and then the movable body 22 is moved to the second displacement position by the first pressing means 31, 33, and 34.

FIG. 1 is a plan view of a so-called charge control type inkjet printer, and FIG. 2 is a simplified cross-sectional view taken along the section line - in FIG.
Ink flows from a pump (not shown) through a solenoid valve (not shown), and from a pipe line 2 to an inkjet nozzle 3.
given to. The cross section seen from the cutting plane line in Fig. 1 along the axis of the inkjet nozzle 3 is 3.
1, and its front view is shown in FIG. 32. Mechanical vibrations are applied to the ink supplied from the conduit 2 by an ultrasonic vibrator. An ink jet 5 is ejected at high speed from the nozzle hole 4 toward a recording paper 7 on a platen 6 provided on a machine body 16. The mechanical vibration of the ink causes the ink stream to break up into droplets of uniform size. When the droplet is separated, the charging electrode 8 is charged by electrostatic induction caused by a pulse applied from a power source 9. This charging action is selectively performed depending on the characters such as characters to be recorded. The ink particles are deflected by an electric field within the deflection electrode 10 by an amount of deflection corresponding to the amount of charge possessed by the ink particles, and the recorded characters are scanned in the vertical direction (up and down in FIG. 2).

Guide rods 11, 12 are disposed parallel to the platen 6, and the carriage 13 is moved by the guide rods 11, 12 in the movement direction 21 and the opposite direction. The carriage 13 is provided with a nozzle 3, a charging electrode 8, and a deflection electrode 10, and is also equipped with a gutter 14 for collecting excess ink and guiding it to a conduit 56. One end of a wire 15 is connected to the carriage 13 . This wire 15 is wound around a pulley 17 provided on the fuselage 16, and the drive pulley 18
The other end of the wire 15 is connected to the carriage 13 via a pulley 19, making it endless. The drive pulley 18 is rotationally driven by a motor 20.

On the carriage 13 is a guide 2 that guides the movable body 22 in parallel to the moving direction 21 of the carriage 13.
3 is provided. A front view of the moving body 22 viewed from the nozzle 3 side is shown in FIG. FIG. 5 is a sectional view taken along the section line - in FIG. 1, with the nozzle 3 omitted. A charging electrode 8 is attached to the moving body 22 . When the stopper 24 formed at the front end of the moving body 22 in the moving direction 21 comes into contact with the nozzle 3, the axis of the charging electrode 8 coincides with the nozzle hole 4 of the nozzle 3. When the carriage 13 moves in the moving direction 21, recording is performed on the recording paper 6 by the ink jet. When recording is finished, Aircraft 1
A buffer spring 25 provided at 6 abuts against the movable body 22 . The movable body 22 has a pad 2 facing the nozzle 3 side and located behind the charging electrode 8 in the moving direction 21.
7 is embedded. This pad 27 is made of, for example, a nonwoven fabric and has liquid absorbing properties, and has the property of absorbing ink well. Moving direction 21 of the moving body 22
A buffer spring 28 is fixed to the rearmost end.
The pad 27 can come into contact with an end surface 30 (see FIG. 3) of the nozzle 3 in which the nozzle hole 4 is formed.

The body 16 has a moving direction 21 of the carriage 13.
At the rear end position of the solenoid mechanism 31 and the set bar 34 which is rotationally displaced around the shaft 33 in the direction of the arrow 32 by the excitation of the solenoid mechanism.
and is provided. When the solenoid mechanism 31 is not energized, the set bar 34 is in the position shown by the solid line in FIG. 1, and when energized it is angularly displaced to the position shown by the phantom line 35. This allows the set bar 34 to collide with the buffer spring 28. The solenoid mechanism 31 includes a coil, a plunger that moves in a direction perpendicular to the paper plane of FIG. 1 when the coil is excited, and a link that angularly displaces the shaft 33 by the linear movement of the plunger.
It includes a spring that returns the shaft 33 so that the set bar 34 is in the solid line state.

Referring to FIG. 6, power from commercial power supply 36 is applied to power supply circuit 38 via main switch 37. Referring to FIG. Power from this power supply circuit 38 is applied to a control drive device 41 and an inkjet generator 42 through a relay switch 40 of a relay 39. The control drive device 41 controls the inkjet printer and drives the motor 20 for moving the carriage 13. The ink jet generator 42 controls the pump that supplies ink, the electromagnetic valve that controls the supply of ink, and drives an ultrasonic vibrator. The power supply circuit 38 also includes a charging electrode 8 and a high voltage electrode 10.
etc. are connected. Terminals 43, 4 of power supply circuit 38
4 is connected to a capacitor 45. terminal 43
is connected to a common contact 46 of relay switch 40. Relay coil 47 of relay 39 is excited when power switch 37 is turned on.
Individual contacts 48 of the relay switch 40 are connected to a control drive 41 and an inkjet generator 42. A resistor 50 and a capacitor 5 are connected between the other individual contact 49 and the grounded terminal 44.
1 are connected in series. The capacitor 51 has
A series circuit including a reversely connected Zener diode 52 and a resistor 53 is connected in parallel. A connection point 54 between the Zener diode 52 and the resistor 53 is connected to the gate of the thyristor 55. Individual contact 4
9 and the terminal 44, the solenoid mechanism 31 and the thyristor 55 are connected in series. In the relay 39, when the relay coil 47 is not excited, the common contact 46 is electrically connected to the individual contact 49, and when the relay coil 47 is excited, the common contact 46 is electrically connected to the individual contact 48.

When the main switch 37 is still closed during recording, the rear end 13a of the carriage 13 in the moving direction 21 is at the position indicated by reference numeral 57 in FIG. The set bar 34 is in the position shown in the first figure, so that the set bar 34 is in the position shown in the first diagram.
Do not touch 8.

When the main switch 37 is turned on, the relay switch 47 of the relay 39 is energized. This causes the common contact 46 of the relay switch 40 to conduct to the individual contact 48, so that the control drive 41
And power is supplied to the inkjet generator 42. Further, the capacitor 45 is charged to the voltage between the terminals 43 and 44. The motor 20 moves the carriage 13 in the direction of movement 21 so that the movable body 22 abuts against the damping spring 25 . As a result, the stopper 24 of the movable body 22 is connected to the nozzle 3.
remains in contact with the nozzle hole 4 and the charged electrode 8.
The axes of the two will align and the recorder will be ready for recording.

Driven by the motor 20, the carriage 13 returns to the return position 57 at the left end of the platen 7, moves again in the moving direction 21, and performs a recording operation on the recording paper 1 as shown in the first figure. When the printing operation is completed, the rear end 13a of the carriage 13 returns to the return position 57 and remains stationary. When the main switch 37 is then shut off, the relay coil 47 of the relay 39 is demagnetized. Therefore, the common contact 46 of the relay switch 40 is electrically connected to the individual contact 49. In this way, current flows from capacitor 45 to capacitor 51 via resistor 50. When the voltage across the capacitor 51 gradually increases and exceeds the breakdown voltage of the Zener diode 52, the Zener diode 52 breaks down and becomes conductive.
This causes the thyristor 55 to fire and become conductive. Therefore, the solenoid mechanism 31 is excited by the current from the capacitor 45. In other words,
After a predetermined time T has elapsed since the main switch 37 was cut off, the Zener diode 52 and the thyristor 55 become conductive, and the solenoid mechanism 31
is excited. Said time T may be approximately 1 second, for example. By energizing the solenoid mechanism 31, the set bar 34 is angularly displaced in the direction of the arrow 32, and the movable body 22 is moved in the moving direction 2 via the buffer spring 28.
1 direction. At this time, the carriage 13
remains stationary. Therefore, the pad 27 is attached to the outer peripheral end surface 3 of the nozzle hole 4 of the inkjet nozzle 3.
0 to wipe away unnecessary ink 60 (see FIG. 3) adhering to the outer periphery of the nozzle hole 4. In this way, the unnecessary ink 60 is absorbed by the pad 27 and wiped away. A predetermined time T after the main switch 37 is shut off.
Since the movable body 22 is moved by the action of the set bar 34 after the wiping period has elapsed, there is almost no further ink leakage from the nozzle hole 4 after wiping. When the capacitor 45 is discharged and its electric capacity becomes zero, the thyristor 55 is turned off and cut off, and the solenoid mechanism 31 is demagnetized. This causes the set bar 34 to be displaced in the opposite direction of the arrow 32 and return to the state shown.

When the main switch 37 is turned on again, the carriage 13 is moved in the moving direction 21 by the action of the motor 20 before printing, and the movable body 22 hits the buffer spring 25, causing the carriage 13 to move in the moving direction 21. , the stopper 24 of the movable body 22 comes into contact with the inkjet nozzle 3, so that the axes of the nozzle hole 4 and the charging electrode 8 are aligned. Thereafter, the carriage 13 moves in the opposite direction of the movement direction 21 and returns to the return position 57. Then, recording is performed again while the carriage 13 is moving in the moving direction 21. At this time, the solenoid mechanism 31 is not energized, and the set bar 34 remains stationary at the position shown by the solid line in FIG.

In the embodiment described above, the carriage 13 is in the return position 5.
7, if the main switch 37 is shut off, the set bar 34 will not hit the buffer spring 28 even if the set bar 34 is angularly displaced in the direction of the arrow 32, so that the ink jet nozzle 3 A problem may arise in that the end face 30 is not wiped away by the pad 27. However, since the main switch 37 is generally shut off after all recording is completed, the above-mentioned problem is not important from the viewpoint of maintaining recording quality.

As described above, according to the present invention, the pad is moved to the nozzle hole and its outer circumferential end surface to wipe and absorb unnecessary ink during a recording pause, so the nozzle hole and its outer circumference are cleaned, and the nozzle hole is cleaned. is clogged,
The recording quality is maintained without changing the ejection direction of the ink jet or changing the particle size of the ink particles.

In particular, in the present invention, the carriage 13 includes a nozzle 3.
and the movable body 22 to which the pad 27 is fixed are only provided, and the structure can be relatively lightweight. Therefore, it is easily possible to make recording movement at a high speed, and the inertial force can be reduced, and in this way, it is possible to improve the recording speed.

Furthermore, the movable body 22 is made reciprocally displaceable in the carriage 13 along the moving direction of the carriage 13, and the movable body 22 is moved by the first pressing means 31, 33, 34 and the second pressing means 25. Since the device is pressed against the device, the structure for its movement is simplified, it can be made smaller, and it can be easily controlled. In this way, the present invention has the revolutionary effect of being able to solve all of the problems in the prior art described above.

[Brief explanation of the drawing]

FIG. 1 is a simplified plan view of an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the cutting plane line in FIG. 1 to explain the principle of an ink jet printer, and FIG. 4 is a front view of the movable body 22 seen from the ink jet nozzle 3 side, FIG. 5 is a sectional view taken from the cutting plane line in FIG. 1, and FIG. 6 is a diagram showing the structure of the ink jet nozzle 3. FIG. 3 is an electrical circuit diagram of the above-mentioned inkjet printer. 3... Ink jet nozzle, 4... Nozzle hole, 5... Ink jet, 8... Charging electrode, 1
0... Deflection electrode, 14... Gutter, 22... Moving body, 23... Guide, 27... Pad.

Claims (1)

[Claims] 1. A platen 6, and a longitudinal guide means 1 arranged parallel to the platen 6.
1 and 12, and is guided by a longitudinal guide means to be able to reciprocate between a first moving position 57 for waiting and a second moving position opposite to the waiting position 57. and means 1 for driving the carriage 13 to move between a first movement position 57 and a second movement position.
7, 18, 19, 20, a nozzle 3 fixed to the carriage 13 and ejecting the ink jet 5 toward the platen 6, and a first nozzle 3 attached to the carriage 13 along the direction of movement thereof.
The carriage 13 is moved between the first displacement position near the movement position 57 and the second displacement position near the second movement position.
such a movable body 22 is provided to be movable back and forth relative to the movable body 22 and allows the ink jet from the nozzle 3 to reach the platen 6 when in the first displacement position; When the body 22 is in the second displacement position, it abuts the nozzle hole 4 of the nozzle 3;
a pad 27 having the property of absorbing ink; first pressing means 31, 33 provided near the first movement position and pressing the moving body 22 to the second displacement position;
34, and a second pressing means 25 that is provided near the second movement position and presses the moving body 22 to the first displacement position, and at the start of the recording operation, the driving means 17, 18, 1
9 and 20 first move the carriage 13 from the first movement position 57 to the second movement position, whereby the second pressing means 25 sets the moving body 22 to the first displacement position, and then moves the carriage 13 to the second movement position. It moves backward to the first movement position 57, performs recording during the subsequent forward movement, and when the recording is finished, the driving means 17, 18, 19, 2
0 is an inkjet printer characterized in that the carriage 13 is returned to the first movement position 57, and then the moving body 22 is moved to the second displacement position by the first pressing means 31, 33, and 34.