JP2000006393A - Liquid discharging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suitably remove a foreign matter by adding a mechanical vibration, whose conditions change with time, to a liquid in a liquid discharging unit in the case of discharging the liquid from the unit. SOLUTION: An electro-mechanical transducer 24 is vibrated by a drive signal from a driving circuit 100' by switching a switch S. The vibration of the transducer 24 is transmitted to an ink via a flexible wall 22 and vibrated. The transducer 24 is driven by the circuit 100' in parallel at the time of sucking an ink by covering a nozzle surface of a print head 2 with a cap. Thus, the ink is sucked by a sucking unit while giving a vibration to the ink of an ink liquid chamber 23. Thus, the vibration changed under conditions such as a frequency, an amplitude width or the like is applied to the ink so that a foam or a solid material of a shape in a various size adhered to an inner wall of the chamber 23 or the nozzle is easily released and is scarcely readhered, and hence it can be easily discharged along with a flow of the ink by the sucking.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid ejecting apparatus, and more particularly, to a liquid ejecting apparatus such as an ink jet printer.
The present invention relates to a liquid ejecting apparatus that ejects a liquid from a liquid ejecting unit and records a trace of ejecting the liquid on a recording medium such as paper, cloth, nonwoven fabric, and plastic film.

[0002]

2. Description of the Related Art For example, in an ink jet printer, characters or images are printed by ejecting ink droplets (liquid) from a liquid ejection portion, that is, a print head, onto print paper (recording medium). In the case of color printing, the print head has ink heads for each of the four colors, for example, cyan, magenta, yellow, and black, and expresses various colors and patterns by combining ink dots sprayed from each ink head. ing. The combination of the colors of the ink dots and the characters and images formed by them are specified by drawing data supplied from a control device (computer). The density of ink dots constituting characters and images is usually several tens to several hundreds of dpi.

[0003] The print head is supplied with ink directly from an ink tank or through an ink tube. When performing initial ink passage from the ink tank to the print head, a pressure difference between the ink tank and the print head tip where the ink tank side is relatively higher than the print head tip side is pressure-fed. The pressure is generated by suction or pressurization by a pump.

When discharging (purging) foreign matter such as air bubbles and solids mixed in the liquid chambers and nozzles of the print head, the foreign matter is also discharged from the nozzles by ink pressure feeding. In that case, in order to increase the ability to discharge foreign substances,
Purging the liquid in the print head while applying mechanical vibration is described in, for example, JP-A-58-112751.

[0005]

As described above, when purging is performed while applying vibration to the liquid, although the ability to discharge foreign substances is improved as compared with the case where no vibration is applied, depending on the size and shape of the foreign substances. Was not effective enough.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to realize a liquid ejecting apparatus for appropriately removing foreign substances such as bubbles and solids contained in a liquid.

[0007]

According to a first aspect of the present invention, there is provided a liquid ejecting apparatus for ejecting a liquid from a liquid ejecting unit to record a trace of ejection of the liquid on a recording medium. A liquid discharging unit that discharges the liquid from the liquid discharging unit; and a mechanical unit that changes the condition of the liquid in the liquid discharging unit over time when the liquid discharging unit discharges the liquid from the liquid discharging unit. Vibrating means for performing vibration,
A liquid ejection device comprising:

According to the first aspect of the present invention, the liquid is discharged from the liquid discharging unit by the liquid discharging unit while the liquid in the liquid discharging unit is subjected to mechanical vibration whose conditions change over time by the vibrating unit.

(2) The invention according to claim 2 for solving the problem is characterized in that the vibrating means causes the liquid to perform mechanical vibration whose frequency changes with time. Item 10. The liquid ejection device according to item 1.

According to the second aspect of the present invention, the liquid is discharged from the liquid discharging unit by the liquid discharging unit while the liquid in the liquid discharging unit is subjected to mechanical vibration whose frequency changes with time by the vibrating unit.

(3) The invention according to claim 3 for solving the problem is characterized in that the vibrating means causes the liquid to perform mechanical vibration whose frequency increases with time. Item 3. A liquid ejection device according to item 2.

According to the third aspect of the present invention, the liquid is discharged from the liquid discharging unit by the liquid discharging unit while the vibrating unit causes the liquid in the liquid discharging unit to perform mechanical vibration whose frequency increases with time.

(4) The invention according to claim 4 for solving the problem is characterized in that the vibrating means causes the liquid to perform mechanical vibration whose frequency decreases with time. Item 3. A liquid ejection device according to item 2.

According to the fourth aspect of the present invention, the liquid is discharged from the liquid discharging unit by the liquid discharging unit while the liquid in the liquid discharging unit is subjected to mechanical vibration whose frequency decreases with time by the vibrating unit.

(5) The invention according to claim 5 for solving the problem is characterized in that the vibrating means causes the liquid to perform mechanical vibration whose amplitude changes with time. Item 10. The liquid ejection device according to item 1.

According to the fifth aspect of the present invention, the liquid is discharged from the liquid discharge unit by the liquid discharge unit while the liquid in the liquid discharge unit is subjected to mechanical vibration whose amplitude changes with time by the vibration unit.

(6) The invention according to claim 6 for solving the problem is characterized in that the vibrating means causes the liquid to perform mechanical vibration whose frequency and amplitude change with time. The liquid ejecting apparatus according to claim 1.

According to the sixth aspect of the present invention, the liquid is discharged from the liquid discharging unit by the liquid discharging unit while the vibrating unit causes the liquid in the liquid discharging unit to mechanically change in frequency and amplitude with time. .

(7) The invention according to claim 7 for solving the problem is characterized in that the liquid discharge section discharges liquid by utilizing mechanical deformation of an electromechanical transducer. A liquid ejection apparatus according to any one of claims 1 to 6.

According to the seventh aspect of the present invention, the liquid discharging section discharges the liquid by utilizing the mechanical deformation of the electromechanical transducer. (8) The invention according to claim 8 for solving the problem is characterized in that the vibrating means causes the liquid to mechanically vibrate using mechanical deformation of an electromechanical transducer. A liquid ejecting apparatus according to any one of claims 1 to 7.

According to the invention of claim 8, the vibration means vibrates the liquid by utilizing the mechanical deformation of the electromechanical transducer. (9) The liquid ejecting apparatus according to claim 8, wherein the electromechanical conversion element is also used for the liquid ejecting section. It is.

According to the ninth aspect of the present invention, the vibrating means vibrates the liquid by also using the electromechanical transducer for the liquid discharge section. (10) The invention according to claim 10 for solving the problem is characterized in that the liquid discharging means discharges the liquid by suction. It is a liquid discharge device of the statement.

According to the tenth aspect, the liquid discharging means discharges the liquid by suction. (11) The invention according to claim 11 for solving the problem, wherein the liquid discharging means discharges the liquid by pressurization. A liquid ejection device according to (1).

In the eleventh aspect, the liquid discharging means discharges the liquid by pressurization.

[0025]

Embodiments of the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiment. Further, an example in which the recording medium is paper will be described. However, the recording medium is not limited to paper, but includes cloth, nonwoven fabric, plastic film, and any other medium capable of holding a trace of liquid ejection.

FIG. 1 shows a schematic configuration of a main part of an ink jet printer. This device is an example of an embodiment of the liquid ejection device of the present invention. This apparatus has a print head 2 that prints (records) on a print paper (not shown) by discharging ink from nozzles. The print paper (not shown) is an example of the embodiment of the recording medium in the present invention. The print head 2 is an example of an embodiment of the liquid ejection unit in the present invention. Ink is supplied to the print head 2 from the ink cartridge 3 via the filter 4 and the ink tube 5. Ink is an example of a liquid embodiment in the present invention.

The apparatus also has a cap 6 that can be put on the nozzle surface of the print head 2. The cap 6 moves forward and backward by the operation of the solenoid valve 7, and covers the nozzle surface of the print head 2 in the advanced state, and separates from the nozzle surface of the print head 2 in the retracted state.

A suction passage 10, a suction means 12, a discharge passage 16 and a collection cartridge 11 are connected in series to the cap 6. The suction means 12 includes a pump 13 and a motor 14. The cap 6, the suction passage 10, the suction means 12, and the discharge passage 16 are an example of an embodiment of the liquid discharge means in the present invention.

The ink is sucked (discharged) by covering the nozzle surface of the print head 2 with the cap 6 and driving the pump 13 by the motor 14 so that the ink is sucked from the nozzles of the print head 2 to the suction passage 10. Has become. As a result, the ink in the ink cartridge 3 is sucked into the suction passage 10 via the filter 4, the ink tube 5, and the print head 2. The sucked ink is collected by the collection cartridge 11 via the pump 13 and the discharge passage 16.

Although not shown in FIG. 1, the print head 2 is provided with vibrating means for applying mechanical vibration to the ink inside the print head. FIG. 2 shows a schematic configuration of the print head 2 provided with the vibrating means for one nozzle. As shown in the figure, the liquid chamber 23 and the nozzle 25 of the print head 2 are filled with ink guided by the ink tube 5.

An electromechanical transducer 24 such as a piezoelectric element is mounted on the flexible wall 22 of the liquid chamber 23. The electromechanical conversion element 24 is configured to apply an electric pulse from the pulse generator 100. The application of the electric pulse causes the electromechanical conversion element 24 to bend toward the liquid chamber 23 together with the flexible wall 22, thereby rapidly reducing the volume of the liquid chamber 23. The ink in the liquid chamber 23 is ejected from the nozzle 25 as ink droplets by the pressure generated by the sudden decrease in the volume of the liquid chamber 23.

At the end of the electric pulse, the bending of the electromechanical transducer 24 returns to its original state, and the liquid chamber 23 recovers its original volume. At this time, the ink flows into the liquid chamber 23 through the ink tube 5 to make up for the discharge amount. By repeating such an operation, printing by ink ejection is performed.

The electromechanical transducer 24 can be driven by the drive circuit 100 'by switching the switch S. The drive circuit 100 'supplies a drive signal to the electromechanical transducer 24 to cause it to vibrate. The vibration of the electromechanical transducer 24 is transmitted to the ink via the flexible wall 22 and causes the ink to vibrate. Drive circuit 1
00 ′ and the electromechanical transducer 24 are an example of the embodiment of the vibration means in the present invention.

The driving of the electromechanical transducer 24 by the drive circuit 100 ′ is performed in parallel with the suction of ink by covering the nozzle surface of the print head 2 with the cap 6. As a result, ink is sucked by the suction unit 12 while applying vibration to the ink in the liquid chamber 23.

The drive circuit 100 'changes the drive signal to change the vibration of the electromechanical transducer 24 during the suction period, thereby changing the vibration of the ink. One form of vibration change involves changing the frequency of the vibration. When the frequency is changed, there are a case where the frequency is gradually increased as shown in FIG. 3A and a case where the frequency is gradually reduced as shown in FIG. 3B. Alternatively, a combination of these may be repeated as shown in (c) of FIG. The frequency may be increased or decreased in a binary manner as shown in FIG. Such a frequency change is realized, for example, by frequency-modulating the drive signal.

In another form of vibration change, the amplitude of the vibration is changed. When the amplitude is changed, the amplitude is repeatedly increased or decreased at a constant or random cycle as shown in FIG. The amplitude may be increased or decreased in a binary manner as shown in FIG. Such an amplitude change is realized by, for example, amplitude-modulating the drive signal.

In still another mode of the vibration change, the above-mentioned 2
Combine the two forms to change both the frequency and amplitude of the vibration. This is realized, for example, by simultaneously performing frequency modulation and amplitude modulation of the drive signal.

As described above, by applying vibrations having changed conditions such as frequency and amplitude to the ink, bubbles and solids of various sizes and shapes adhered to the liquid chamber 23 and the inner wall of the nozzle can be easily separated. Since re-adhesion becomes difficult, the ink can be easily discharged along with the flow of ink by suction. That is, foreign substances can be efficiently purged.

The above is an example in which the electromechanical transducer 24 is used as a drive source for ejecting ink during printing and a drive source for exciting ink during suction, which is preferable in that the configuration can be simplified. Of course, the electromechanical transducer for vibration may be provided separately from the one for ink ejection.

FIG. 5 shows such an embodiment. In this figure, the same parts as those shown in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted. In this embodiment, an electromechanical transducer 24 ′ for vibration is attached to the print head 2 at a wall 22 ′ opposite to the flexible wall 22, and the vibration of the electromechanical transducer 24 ′ is reduced To be added to the ink. Even with such a configuration, an efficient foreign matter purging effect can be performed similarly to the above.

The above is an example in which ink is discharged by suction. However, discharge of ink is not limited to suction, but may be performed by pressure feeding. FIG. 6 shows such an embodiment. In this figure, the same parts as those shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

In this embodiment, a pressurizing pump 30 is provided in the ink cartridge 3, and the ink is pressurized by the pressurizing pump 30 while the print head 2 is covered with the cap 6, and the ink is discharged from the nozzle. Through the collecting cartridge 11. And
During such ink discharge, the print head 2 vibrates the ink by vibrating means as shown in FIG. 2 or FIG.

[0043]

As described above in detail, according to the first aspect of the present invention, the vibrating means causes the liquid in the liquid discharge unit to undergo mechanical vibration whose conditions change with time, while the liquid is discharged by the liquid discharging means. Since the liquid is discharged from the liquid discharge unit, it is possible to realize a liquid discharge apparatus that appropriately removes foreign matters such as bubbles and solids contained in the liquid.

According to the second aspect of the present invention, the liquid is discharged from the liquid discharging unit by the liquid discharging unit while the vibrating unit makes the liquid in the liquid discharging unit mechanically change the frequency with time. With this configuration, it is possible to realize a liquid ejecting apparatus that appropriately removes foreign matters such as bubbles and solids contained in the liquid.

According to the third aspect of the present invention, the liquid is discharged from the liquid discharge unit by the liquid discharge unit while the liquid in the liquid discharge unit is subjected to mechanical vibration whose frequency increases with time by the vibrating unit. With this configuration, it is possible to realize a liquid ejecting apparatus that appropriately removes foreign matters such as bubbles and solids contained in the liquid.

According to the fourth aspect of the present invention, the liquid is discharged from the liquid discharging unit by the liquid discharging unit while the liquid in the liquid discharging unit is subjected to mechanical vibration whose frequency decreases with time by the vibrating unit. With this configuration, it is possible to realize a liquid ejecting apparatus that appropriately removes foreign matters such as bubbles and solids contained in the liquid.

According to the fifth aspect of the invention, the liquid is discharged from the liquid discharge unit by the liquid discharge unit while the liquid in the liquid discharge unit is subjected to mechanical vibration whose amplitude changes with time by the vibration unit. With this configuration, it is possible to realize a liquid ejecting apparatus that appropriately removes foreign matters such as bubbles and solids contained in the liquid.

According to the sixth aspect of the present invention, the liquid is discharged from the liquid discharge section by the liquid discharge section while the liquid in the liquid discharge section is subjected to mechanical vibration whose frequency and amplitude change with time by the vibration section. Since the liquid is ejected, it is possible to realize a liquid ejecting apparatus that appropriately removes foreign matters such as bubbles and solids contained in the liquid.

According to the seventh aspect of the present invention, since the liquid discharging section discharges the liquid by utilizing the mechanical deformation of the electromechanical transducer, the liquid can be discharged appropriately.

According to the eighth aspect of the present invention, the vibrating means vibrates the liquid by utilizing the mechanical deformation of the electromechanical transducer, so that the liquid can be vibrated appropriately.

According to the ninth aspect of the present invention, the vibrating means vibrates the liquid by also using the electromechanical transducer for the liquid discharge section, so that the configuration can be simplified.

According to the tenth aspect of the present invention, since the liquid discharging means discharges the liquid by suction, the liquid can be discharged properly. Claim 11
According to the invention, since the liquid discharging means discharges the liquid by pressurization, the liquid can be discharged appropriately.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a main part of an apparatus according to an example of an embodiment of the present invention.

FIG. 2 is a diagram illustrating a schematic configuration of a print head of an apparatus according to an example of an embodiment of the present invention.

FIG. 3 is a graph showing a frequency change of a vibration unit in an apparatus according to an embodiment of the present invention.

FIG. 4 is a graph showing a change in amplitude of a vibration unit in the apparatus according to the embodiment of the present invention;

FIG. 5 is a diagram showing a schematic configuration of a print head of an apparatus according to an example of an embodiment of the present invention.

FIG. 6 is a diagram showing a schematic configuration of a main part of an apparatus according to an example of an embodiment of the present invention.

[Explanation of symbols]

 2 Print head 3 Ink cartridge 5 Ink tube 6 Cap 7 Solenoid valve 11 Recovery cartridge 12 Suction means 22 Flexible wall 23 Liquid chamber 24 Electromechanical conversion element 25 Nozzle 100 Pulse generator 100 'Drive circuit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C056 EA15 EC03 EC08 EC24 EC56 EC59 FA04 2C057 AF72 AF80 AG44 BA05 BA14 4H057 AA03 DA01 DA23 DA34 FA13 FA90 GA06 HA90

Claims (11)

[Claims] 1. A liquid ejecting apparatus for ejecting a liquid from a liquid ejecting unit to record an ejection mark of the liquid on a recording medium, wherein the liquid ejecting unit ejects the liquid from the liquid ejecting unit, and the liquid ejecting unit. And a vibrating means for causing the liquid in the liquid discharge unit to perform a mechanical vibration whose conditions change over time when the liquid is discharged from the liquid discharge unit. . 2. The liquid ejecting apparatus according to claim 1, wherein the vibrating means causes the liquid to perform mechanical vibration whose frequency changes with time. 3. The liquid discharging apparatus according to claim 2, wherein the vibrating means causes the liquid to perform mechanical vibration whose frequency increases with time. 4. The liquid discharging apparatus according to claim 2, wherein the vibrating means causes the liquid to perform mechanical vibration whose frequency decreases with time. 5. The liquid discharging apparatus according to claim 1, wherein the vibrating means causes the liquid to perform a mechanical vibration whose amplitude changes with time. 6. The liquid ejecting apparatus according to claim 1, wherein the vibrating means causes the liquid to perform a mechanical vibration whose frequency and amplitude change with time. 7. The liquid discharge unit according to claim 1, wherein the liquid discharge unit discharges the liquid by using mechanical deformation of an electromechanical transducer. Liquid ejection device. 8. The liquid crystal device according to claim 1, wherein said vibration means causes the liquid to mechanically vibrate using mechanical deformation of an electromechanical transducer. The liquid ejection device according to one of the above. 9. The liquid discharging apparatus according to claim 8, wherein the electromechanical transducer is used for the liquid discharging unit. 10. The liquid discharging device according to claim 1, wherein the liquid discharging means discharges the liquid by suction.
The liquid ejection device according to claim 1. 11. The liquid discharging means according to claim 1, wherein the liquid discharging means discharges the liquid by pressurization.
The liquid ejection device according to claim 1.