JP4036071B2 - Liquid ejector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a recording head used in an image recording apparatus such as a printer, a color material ejecting head used for manufacturing a color filter such as a liquid crystal display, an electrode used for forming an electrode such as an organic EL display, FED (surface emitting display), etc. The present invention relates to a liquid ejecting head for discharging a liquid, such as a material ejecting head and a bioorganic matter ejecting head used for biochip manufacturing, and a liquid ejecting apparatus using the liquid ejecting head. Hereinafter, a description will be given of a printing apparatus that forms an image pattern continuous in the main scanning direction using ink that is one of liquids.
[0002]
[Prior art]
2. Description of the Related Art There is known an ink jet printing apparatus that changes the pressure of a liquid that fills a pressure generation chamber and ejects the liquid as a liquid jet from a nozzle connected to the pressure generation chamber.
[0003]
In the ink jet printer widely used, there are a method of using displacement of a piezoelectric element as a pressure generating means of a pressure generating chamber, and a method of using vapor pressure when a liquid is boiled by a heating resistor. In particular, a method using a piezoelectric element is characterized in that a wide variety of liquids can be ejected because the liquid does not require a physical or chemical change such as a boiling phenomenon. In addition, since the piezoelectric element is a device that responds linearly to the drive signal, the pressure can be easily controlled and the form, amount, and speed of the liquid jet ejected from the nozzle can be changed relatively freely. It is.
[0004]
This ink jet printing device, particularly a printing device using a piezoelectric element, can selectively arrange extremely small droplets of several picoliters as recording pixels on a print medium, so that it is not for printing photographic images. It can also be used for pattern formation of electronic circuits.
[0005]
However, the liquid jet ejected from the ink jet print head is not a spherical droplet, but a plurality of droplets are formed by the surface tension of the liquid in the process of flying the liquid jet ejected from the nozzles in the form of elongated columns toward the print medium. After splitting, the droplets are deposited on the print medium to form pixels. In the most common jet form, as shown in FIG. 5, after the liquid column of the liquid jet is split into a large main droplet and an elongated tail portion, the tail portion becomes a small satellite droplet due to surface tension. In some cases, the droplets fly as droplets or the elongated tail portion is further divided into a plurality of minute droplets.
[0006]
There is a problem that these satellite droplets prevent fine pattern formation as noise. In particular, when an electronic circuit pattern is formed, unnecessary circuit formation causes a malfunction of the circuit and becomes a fatal defect. Further, since the satellite droplets are very small, there is a problem that the printing apparatus and the printing medium are contaminated by being stalled due to the influence of air resistance and air flow and floating and flying.
[0007]
In order to solve the problem of deterioration in printing quality due to such satellite droplets, a plurality of ink droplets forming one dot are formed as disclosed in, for example, Japanese Patent Laid-Open No. 59-133066 and US Pat. No. 5,285,215. It has been proposed to discharge from a nozzle opening without interruption, and to merge into one droplet during flight and land on a printing medium. That is, a plurality of continuous drive pulses are applied to the pressure generating means, and the subsequent pulses in these drive pulse trains have a larger voltage change rate than the immediately preceding drive pulse, and the pulse intervals are sequentially reduced. By using such a drive pulse train, droplet groups that continuously increase in speed are ejected from the orifice and merged while the droplet groups fly in the air as a single droplet. Pixels are to be formed.
[0008]
On the other hand, in view of the problem that in these conventional techniques, the drive signal is extremely complicated and difficult to control to an optimum state, Japanese Patent Laid-Open No. 8-336970 discloses a plurality of independent droplets ejected from a nozzle. In addition, a technique for adjusting the drive signal so that the last ejected droplet has a speed at which it merges with the first ejected droplet during flight is disclosed.
[0009]
[Patent Document 1]
JP 59-133066
[Patent Document 2]
US Patent 5,285,215
[Patent Document 3]
JP-A-8-336970
[0010]
[Problems to be solved by the invention]
However, when drawing a line pattern as thin as possible on a print medium, the above-described conventional technique forms a pixel by combining a plurality of droplets, and therefore does not use the smallest droplet that can be ejected from a nozzle as a pixel. Therefore, the highest resolution inherent in the print head is not utilized.
[0011]
Also, when a signal is propagated to a drawn line, disconnection is never allowed. For very small droplets, the ratio of the surface to the volume is large, so continuous droplets are isolated if they do not coalesce with the previous droplets due to surface tension or drying in a short time. As a result, the signal line is broken.
[0012]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and a printing medium in which a continuous pixel is surely connected on a printing medium and satellite droplets are not generated as noise is printed on the printing medium. An object is to provide a technique that can be formed on top.
[0013]
[Means for Solving the Problems]
In order to solve the above-described problems, the liquid ejecting apparatus of the present invention employs the following configuration. That is,
A liquid ejecting apparatus that performs main scanning by moving a liquid ejecting head that ejects a liquid jet relative to a target, and the minimum unit of the liquid jet ejected by the liquid ejecting head The main droplet and the subsequent sub-droplet formed at the head of the liquid droplets are configured to land at the same position on the target. The gist of the invention is that it is configured to collide with the tail portion of the preceding liquid jet before landing on the target.
[0014]
In the first printing apparatus of the present invention, the pixels formed by these adjacent liquid jets on the print medium are necessarily joined, and an image having no defect can be formed with the minimum unit liquid jet. .
[0015]
The second liquid ejecting apparatus of the present invention is a liquid ejecting apparatus that performs main scanning by moving a liquid ejecting head that ejects a liquid jet relative to a target, and the liquid ejecting head ejects the liquid ejecting head. In the minimum unit of the liquid jet, the liquid jet of the minimum unit is configured such that a head of the liquid jet is deposited on the target before the liquid jet of the minimum unit is divided into a plurality of droplets. The gist is that the subsequent liquid jet is configured to collide with the tail portion of the preceding liquid jet before the head of the liquid jet reaches the target.
[0016]
In the second liquid ejecting apparatus of the present invention, the preceding liquid jet reaches the target before splitting, and the subsequent liquid jet leads to the preceding liquid jet before reaching the target. In response to the change in the relative velocity of the liquid ejecting head in the main scanning direction, the pixels formed by these liquid jets adjacent on the target are necessarily joined, and a defect-free image can be formed with the smallest liquid jet. It becomes possible.
[0017]
The third liquid ejecting apparatus of the present invention is characterized in that the continuous liquid jet forms and ejects a continuous liquid column from the liquid ejecting head to the target.
[0018]
In the third liquid ejecting apparatus of the present invention, since the liquid jet that continuously flies forms a bridge of liquid columns between the liquid ejecting head and the target at all times or temporarily, the flow of the liquid jet A stable and continuous thin line pattern can be reliably formed on the target.
[0019]
Further, the fourth liquid ejecting apparatus of the present invention is characterized in that the first to third printing apparatuses are applied to a configuration in which a droplet pattern by the liquid jet is a circuit pattern for propagating a signal.
[0020]
In the fourth liquid ejecting apparatus of the present invention, it is possible to form a high-definition circuit pattern with a high yield with a small and simple apparatus called a liquid ejecting apparatus using a liquid jet.
[0021]
Furthermore, in order to solve the above-described problem, the fifth liquid ejecting apparatus of the present invention enlarges or reduces the volume of the pressure generating chamber, the pressure generating chamber connecting the liquid ejecting head to the nozzle, the nozzle. A piezoelectric element is used.
[0022]
In the fifth liquid ejecting apparatus of the present invention, a piezoelectric element having high linearity of response to an input signal and high controllability is used as a pressure generating element, so that the form, speed, amount, and timing of the ejected liquid jet are increased. The accuracy can be adjusted, and the configuration of the liquid ejecting apparatus of the present invention can be optimally achieved.
[0023]
In the sixth liquid ejecting apparatus of the present invention, when the liquid ejecting apparatus ejects the continuous liquid jet, the electrical resistance measuring unit can measure the electrical resistance between the liquid ejecting head and the target. I made it.
[0024]
In the sixth liquid ejecting apparatus of the present invention, the liquid ejecting is performed by utilizing the fact that the electric resistance is lowered when the continuous liquid jet forms a continuous liquid column in the most part from the liquid ejecting head to the target. It becomes possible to monitor the jet state of the liquid jet of the apparatus.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail based on examples.
[0026]
FIG. 1 is an explanatory diagram illustrating a hardware configuration of the printing apparatus according to the present exemplary embodiment. Hereinafter, how the printing apparatus of the present invention prints an image pattern will be briefly described with reference to FIG. As shown in the drawing, the printing apparatus 10 according to the present embodiment forms a pattern by forming pixels on the printing medium 16 by ejecting a fine liquid jet while reciprocating the carriage 12 on the printing medium 16. A device for printing. A print head for discharging a liquid jet is mounted on the carriage 12. When printing an image pattern, an ink cartridge is usually mounted on the upper surface side of the carriage 12 and ink is supplied to the print head. The print medium 16 is conveyed to a predetermined position below the carriage 12 by the medium feed roller 14. When the print medium 16 is set at a predetermined position, the carriage 12 ejects a liquid jet from the print head while reciprocating on the print medium 16. The carriage 12 is guided to two guide rails 18 as shown in the figure, and is driven by a carriage motor 22 via a drive belt 20. Thus, the operation of reciprocating the carriage 12 is called main scanning. The medium feed roller 14 is driven in synchronization with the main scanning of the carriage 12 to move the print medium 16 little by little in the direction perpendicular to the main scanning direction. In this way, the operation of relatively moving the print head and the print medium in the direction intersecting the main scanning direction is called sub-scanning. Thus, the main scanning of the carriage 12 and the sub-scanning of the printing medium 16 are combined, and in accordance with this, ink jets are formed on the printing medium 16 by ejecting a liquid jet at an appropriate timing. The pattern is printed.
[0027]
In the printing apparatus 10 of this embodiment, the ink cartridge is accommodated in a large-capacity ink container 30 instead of on the carriage 12 in response to a large amount of processing, and an ink supply provided in the carriage 12 is provided via a tube 24. Supplied from the mouth 26 to the print head.
[0028]
Further, as shown in the drawing, the printing apparatus 10 of this embodiment includes a cap 32 that covers the print head when the liquid jet is not discharged, and a nozzle for sucking out ink from the print head in order to prevent nozzle clogging. A suction pump 34 is also provided.
[0029]
FIG. 2 is an explanatory diagram showing a state in which the carriage 12 is viewed from the lower surface side of the carriage 12, that is, from the print medium 16 side. The print head 4 mounted on the lower surface of the carriage 12 includes nozzles 2A, 2A. . . , And 2B, 2B,. . . , And 2C, 2C,. . . , And 2D, 2D,. . . , And are formed in the nozzle rows 3A, 3B, 3C, 3D, respectively. These four nozzle rows are arranged in a staggered manner offset from each other in the nozzle arrangement direction, do not overlap when viewed from the main scanning direction, and are single nozzle rows having a density four times the individual nozzle pitch. It is supposed to function as.
[0030]
In the print head 4 of the present embodiment, a piezoelectric element capable of accurately controlling the form, speed, amount, and timing of the liquid jet to be discharged is used. A mechanism for ejecting a liquid jet by a print head using a piezoelectric element will be described with reference to FIG.
[0031]
As shown in FIG. 3, the print head 4 includes a comb-like piezoelectric element 21 inserted into one of the openings into a storage chamber 72 of a box-like case 71 made of plastic, for example, and a comb-like tip 21a. Faces the other opening. The flow path unit 74 is joined to the surface (lower surface) of the case 71 on the other opening side, and the comb-shaped tip portion 21 a is in contact with and fixed to a predetermined portion of the flow path unit 74.
[0032]
The piezoelectric element 21 is formed by cutting a plate-shaped piezoelectric element substrate in which common internal electrodes 21c and individual internal electrodes 21d are alternately stacked with a piezoelectric body 21b interposed therebetween in a comb-teeth shape corresponding to the nozzle and pressure generation chamber formation density. Configured. Then, by applying a driving voltage between the common internal electrode 21c and the individual internal electrode 21d, each piezoelectric element 21 expands and contracts in the longitudinal direction of the piezoelectric element orthogonal to the stacking direction.
[0033]
The channel unit 74 is configured by laminating the nozzle plate 6 and the elastic plate 77 on both sides with the channel forming plate 75 interposed therebetween.
[0034]
The flow path forming plate 75 communicates with a plurality of nozzle openings 2 formed in the nozzle plate 6 and is arranged at least at one end of each pressure generating chamber 81 and a plurality of pressure generating chambers 81 arranged with a pressure generating chamber partition therebetween. This is a plate material on which a plurality of ink supply portions 82 communicating with each other and an elongated common ink chamber 83 communicating with all the ink supply portions 82 are formed. For example, an elongated common ink chamber 83 is formed by etching a silicon wafer, and pressure generating chambers 81 are formed along the longitudinal direction of the common ink chamber 83 in accordance with the pitch of the nozzle openings 2. A groove-shaped ink supply part 82 can be formed between the ink 81 and the common ink chamber 83. In this case, the ink supply unit 82 is connected to one end of the pressure generating chamber 81, and the nozzle opening 2 is disposed in the vicinity of the end opposite to the ink supply unit 82. The common ink chamber 83 is a chamber for supplying the ink stored in the ink cartridge to the pressure generating chamber 81, and the ink supply port 26 communicates with substantially the center in the longitudinal direction.
[0035]
The elastic plate 77 is laminated on the surface of the flow path forming plate 75 opposite to the nozzle plate 6, and a double structure in which a polymer film such as PPS is laminated as an elastic film 88 on the lower surface side of the stainless steel plate 87. It is. Then, an island portion 89 for abutting and fixing the piezoelectric element 21 is formed by etching a portion of the stainless plate 87 corresponding to the pressure generating chamber 81.
[0036]
In the print head 4 having the above-described configuration, by extending the piezoelectric element 21 in the longitudinal direction of the piezoelectric element, the island part 89 is pressed toward the nozzle plate 6 side, and the elastic film 88 around the island part 89 is deformed to cause pressure. The generation chamber 81 contracts. When the piezoelectric element 21 is contracted in the longitudinal direction from the contracted state of the pressure generating chamber 81, the pressure generating chamber 81 expands due to the elasticity of the elastic film 88. When the pressure generating chamber 81 is once expanded and then contracted, the ink pressure in the pressure generating chamber 81 is increased, and ink is ejected from the nozzle opening 2 as a liquid jet.
[0037]
In other words, in the recording head 4, the capacity of the corresponding pressure generation chamber 81 changes as the piezoelectric element 21 is charged / discharged. By utilizing such pressure fluctuations in the pressure generating chamber 81, ink can be ejected from the nozzle openings 2 or the meniscus (the free surface of the ink exposed at the nozzle openings 2) can be vibrated.
[0038]
In place of the longitudinal vibration mode piezoelectric element 21, a so-called flexural vibration mode piezoelectric element may be used. The piezoelectric element in the flexural vibration mode is a piezoelectric element that contracts the pressure generation chamber by deformation due to charging and expands the pressure chamber by deformation due to discharge.
[0039]
Of course, other than the piezoelectric element as the pressure generating means, for example, a method in which the ink is rapidly heated by a heating resistance element formed in the pressure generating chamber and a part of the ink is boiled, and the vapor pressure is used. It is also possible to employ a method in which a voltage is applied between electrodes facing each other across a narrow gap, and the wall of the pressure generating chamber in which one electrode is formed is bent by electrostatic force. However, these pressure generation methods can be controlled only in one direction, the output as displacement against the input is very non-linear and precise control is difficult, compared to the method using piezoelectric elements. It is difficult to handle.
[0040]
FIG. 4 shows an example of the voltage waveform of the drive signal applied to the piezoelectric element 21.
[0041]
In the drive pulse (drive signal) shown in FIG. 4, when the piezoelectric element 21 contracts by the first rising edge PE <b> 1 of the drive pulse and the volume of the pressure generation chamber 81 is rapidly expanded, the pressure generation chamber 81 from the common ink chamber 83 and the nozzle 2. Ink is sucked into the inside. At this time, the meniscus is largely drawn into the nozzle. The ink flow induced at the rising edge PE1 of the drive pulse then starts to vibrate with a natural period determined by the inertia of the ink and the rigidity of the pressure generating chamber 81. When the induced reverse flow of the ink vibration occurs, that is, when the driving pulse falling PE2 acts in synchronization with the generation of the flow from the pressure generating chamber 81 toward the nozzle 2, the piezoelectric element 21 expands and the pressure generating chamber. The volume of 81 is rapidly contracted, and a strong flow is generated from the pressure generation chamber 81 toward the nozzle 2, and ink is ejected from the nozzle as a liquid jet.
[0042]
Although the form of the liquid jet ejected from the nozzle 2 will be described in detail later, it is appropriate to suppress the timing at which the rear end portion of the liquid jet ejected into an elongated liquid column is cut off and the strong residual vibration of the ink in the pressure generating chamber 81. The rising edge PE3 of the drive pulse enters at a proper timing and intensity, the drive voltage returns to the initial state and prepares for the next drive.
[0043]
In this way, the liquid jet ejected from the nozzle 2 by a series of operations is the minimum unit of on / off of ejection / non-ejection, and gives the minimum unit pixel by the controllable liquid jet.
[0044]
In the above description regarding the drive signal, the piezoelectric element in the longitudinal vibration mode that expands the volume of the pressure generation chamber with respect to a positive voltage change is used. However, in the piezoelectric element in the flexural vibration mode, the deformation direction with respect to the pressure generation chamber is reversed. Therefore, in order to perform the operation used in the above description, it is necessary to reverse the pulse change direction.
[0045]
Next, the form of the liquid jet ejected from the nozzle 2 with respect to the drive signal of FIG. 4 will be described in detail with reference to FIG.
[0046]
In FIG. 4, the ticks inserted at the boundaries of the frames indicate the distance from the nozzle opening at intervals of 100 μm, and the upper end of the illustrated area is approximately 250 μm from the nozzle opening.
[0047]
In the drive signal described above, the nozzle meniscus is once pulled deeply into the back of the nozzle as shown in FIG. 5A by the rising edge of the pulse, and is elongated as shown in FIG. 5B after the trailing edge of the pulse. A columnar liquid jet is ejected from the nozzle. This columnar liquid jet is separated (pinch off) from the liquid portion that fills the nozzle at the time of FIG. 5 (C), and then constricted due to the surface tension of the liquid, as shown in FIG. 5 (D). However, the main droplet is separated at the head at a point of about 200 μm from the nozzle opening. When the liquid jet continues to fly, the tail portion following the main droplet is separated into one or a plurality of minute droplets in FIG. The sub-droplets formed from these tails are also called satellite droplets, which disturb the pixel shape formed by the liquid jet on the print medium or form pixels separated from the pixels formed by the main droplet. It will give noise. Also, the minute satellite droplets are stalled by air resistance, and float between the print head and the print medium, causing the largest contamination.
[0048]
When the main droplet and the satellite droplet separated in this way have a large distance between the print head and the print medium and the relative speed in the main scanning direction between them is large, as shown in FIG. Pixels separated above are formed. Also, in such a case, in order to form a thin line with a continuously jetted liquid jet, the printing apparatus is used under the condition that main liquid droplets of the continuous liquid jet are combined on the print medium as shown in FIG. Must work. However, since the minute liquid jet is extremely affected by the wettability between the nozzle opening liquid and the nozzle surface, a very slight nonuniformity of wettability significantly reduces the straightness of the liquid jet. In particular, the tail portion of a slender and fine liquid jet is greatly affected by wetting, and the landing position of satellite droplets may vary greatly. When the printing apparatus is operated in such a state where the straight running stability is low, the main droplets of the subsequent liquid jet are deflected by colliding with the satellite droplets of the preceding liquid jet flying in an inappropriate direction. As shown in FIG. 6C, the pixel is separated from the preceding pixel by a large distance from the target landing position on the print medium. When this thin line pattern is formed for the purpose of transmitting a signal, such a defect causes a fatal problem as a disconnection of the signal line.
[0049]
Therefore, in the embodiment of the present invention, the printing apparatus is configured so that the surface of the printing medium comes to the position indicated by the thick line in FIG. 7, that is, the position of 180 μm from the nozzle opening. In this configuration of the present embodiment, the liquid jet reaches the print medium before the liquid jet is separated into a plurality of liquid portions as shown in FIG. The tail portion forms an integral pixel as shown in FIG. In this configuration, since the liquid jet reaches the print medium before the tail portion is separated, stable pixel formation can be performed regardless of non-uniformity of nozzle wetting and individual differences of print heads. In addition, since a single pixel can be obtained in a wide range of relative speed in the main scanning direction, the apparatus configuration can be flexibly performed. Further, in the present embodiment, as shown in FIG. 9, by appropriately shortening the pulse interval T1 for continuously ejecting the liquid jet, in the continuous liquid jet of the smallest unit, the head of the subsequent liquid jet is the print medium. Before landing on the liquid jet, it collides with the tail portion of the preceding liquid jet. That is, by this drive signal, as shown in FIG. 7C, while the first liquid jet is flying, the print head performs the operation of forming the subsequent liquid jet by the drive pulse for the second liquid jet. Is greatly drawn. Then, as shown in FIG. 7E, the leading end of the subsequent liquid jet is connected to the tail portion of the preceding liquid jet to form an integrated liquid column. With such a configuration, the succeeding liquid jet can surely form pixels connected to the preceding liquid jet, so that very fine thin lines as shown in FIG. 8B can be drawn without any defects. Thereby, especially the availability of the inkjet application to signal line pattern formation can be raised significantly.
[0050]
When the pulse interval T1 of the driving signal is further shortened with respect to the above embodiment, the liquid jet is coupled with the tail portion of the preceding liquid jet at the time when the liquid jet is ejected from the nozzle, and the continuous liquid jet is always from the print head to the print medium. It flows out like a continuous liquid column bridge. In such a configuration, it is possible to maintain an injection state that is extremely stabilized by the preceding flow. Therefore, a printing apparatus with extremely high drawing accuracy can be configured.
[0051]
Further, when the distance between the print head and the print medium is increased with respect to the above-described embodiment, the main droplet and the tail portion are separated before the tip of the liquid jet reaches the print medium. Even in such a flying state, when the distance between the print head and the print medium is close to some extent and the relative speed in the main scanning direction is somewhat small, the main droplet and tail form a single pixel combined on the print medium. it can. Since the subsequent liquid jet collides with the tail portion of the preceding liquid jet and flies together, the fine line pattern can be stably formed even under such conditions. However, in order to obtain the ultimate stability, the condition that the main droplet reaches the print medium before separation is effective as in the previous embodiment.
[0052]
In order to configure the tail portion of the preceding liquid jet and the head of the succeeding liquid jet in the present invention so as to collide and connect during the flight, the liquid jet ejection mode and the liquid jet to be ejected continuously It is extremely important to optimally adjust the time difference.
[0053]
The jet form of the liquid jet is governed by the velocity distribution in the liquid jet. In order to control this speed distribution, the pressure change in the pressure generating chamber is controlled. A print head using a piezoelectric element as a pressure generating means is extremely effective for such control. Since the piezoelectric element responds linearly to the input signal pulse within the range of the response frequency, the volume of the pressure generating chamber can be increased or decreased. Furthermore, the speed and size of enlargement and reduction can be precisely set by changing the rise and fall time and height of the pulse and the pulse width. This means that the pressure pattern of the pressure generating chamber can be precisely set by the piezoelectric element, and the piezoelectric element is extremely effective for the print head of the present invention. For the same reason, it is clear that the piezoelectric element is most suitable for determining the injection amount of each minimum unit liquid jet and shortening the injection interval while maintaining a good injection state.
[0054]
In contrast to a piezoelectric element, an ink jet system using a heating resistor element or an electrostatic actuator can control only one of positive and negative pressure changes, so that the operation of the present invention is extremely limited. This is possible only under conditions, and the flexibility regarding the drawing pattern cannot be obtained.
[0055]
Now, with the configuration of the present invention as described above, extremely stable drawing performance can be obtained. However, in order to optimally set and maintain the operation state as an apparatus, means for monitoring the operation state is necessary. However, in the configuration of the present invention, the distance between the print head and the print medium is extremely small, and it is difficult to directly observe the jet state of the liquid jet.
[0056]
On the other hand, it is possible to determine the injection state indirectly by the following configuration. That is, when the liquid jet is continuously ejected, in the above-described configuration of the present invention, a liquid flow bridge is formed from the print head to the print medium, or the liquid column occupies most of the gap from the print head to the print medium. ing. In these states, when a voltage is applied between the conductor placed at the position of the print medium and the print head, a current flows through the liquid jet. Therefore, by measuring the current value, that is, the resistance value, the liquid jet is measured. You can know the state of.
[0057]
For example, in FIG. 1, an electrode plate placed in the same gap as the print medium is installed near the cap 32, and a resistance value measurement is performed while operating the print head at this position, thereby constructing a system that optimizes the operation state. . It is also effective to previously form electrodes for checking the ejection state on the print medium and check during the drawing operation.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating the configuration of a printing apparatus according to an embodiment.
FIG. 2 is an explanatory diagram illustrating the configuration of a print head according to an embodiment.
FIG. 3 is an explanatory diagram illustrating the internal structure of the print head according to the embodiment.
FIG. 4 is an example of a drive signal for explaining the operation of the print head.
FIG. 5 is an explanatory diagram of a liquid jet ejected from a print head.
FIG. 6 is an explanatory diagram of a drawing pattern formed by a conventional printing apparatus.
FIG. 7 is an explanatory diagram of a liquid jet ejected from the print head of the present embodiment.
FIG. 8 is an explanatory diagram of a drawing pattern formed by the printing apparatus according to the present embodiment.
FIG. 9 is an example of a drive signal for the print head of the present invention.
[Explanation of symbols]
2 ... Nozzle
4 ... Print head
6 ... Nozzle plate
10. Printing device
12 Carriage
16 ... Print medium
21 ... Piezoelectric element
30 ... Ink container
32 ... Cap
34 ... Suction pump
81 ... Pressure generation chamber
82: Ink supply section
83 ... Common ink chamber

Claims (1)

A liquid ejecting apparatus that performs main scanning by moving a liquid ejecting head that ejects a liquid jet relative to a target,
The liquid jet liquid jet head is ejected by the drive pulse used to inject pre SL liquid jet is located closer to the head than the position which splits into a plurality of droplets, and
In the driving pulses continuous, the liquid jet by the subsequent drive pulse, with that holds the surface of the target to a position remote from the head than the position where the rear-end to the tail portion of the liquid jet preceding,
A liquid ejecting apparatus comprising: an electric resistance measuring unit configured to measure an electric resistance between the liquid ejecting head and the target when the liquid jet is ejected continuously .

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