JP3467695B2 - LIQUID EJECTING APPARATUS AND MICRO VIBRATION CONTROL METHOD - Google Patents

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 such as a manufacturing apparatus, a textile printing apparatus, and an industrial machine such as a microdispenser, an image recording apparatus such as a printer or a plotter, and more specifically, a liquid droplet ejecting from a nozzle opening. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid ejecting apparatus having a possible liquid ejecting head, and more particularly to a liquid ejecting apparatus that performs a micro-vibration operation for agitating ink near a nozzle opening.

[0002]

2. Description of the Related Art Some industrial machines and image recording apparatuses are equipped with a liquid ejecting head for ejecting liquid in the form of liquid droplets. For example, as an industrial machine, a manufacturing apparatus that manufactures an optical filter by landing a droplet-shaped coloring material ejected from an ejection head (a type of liquid ejection head) on a filter substrate,
A printing device that prints a pattern by landing a droplet-shaped coloring material ejected from an ejection head on a textile product such as cloth, or by ejecting a very small amount of liquid from the ejection head to a predetermined location. Known are microdispensers and the like. Known image recording apparatuses include printers and plotters that record an image by landing ink droplets ejected from a recording head (a type of liquid ejecting head) on a print recording medium such as paper.

In the liquid jet head used in such industrial machines and image recording apparatuses, the liquid is held by the surface tension of the nozzle opening, and the meniscus, which is the free surface of the liquid, is exposed to the air. Therefore, a solvent such as water or an organic solvent is gradually evaporated through the meniscus. The evaporation of the solvent increases the viscosity of the liquid in the vicinity of the nozzle opening, which causes a problem with the increased viscosity of the liquid. The image recording apparatus will be described below as an example, but the same applies to the industrial machine.

In this type of image recording apparatus, when the viscosity of the ink near the nozzle openings increases, the ejection of ink droplets becomes improper. As a result, the size (ejection amount) of the ink droplets fluctuates, the trajectory is disturbed, and the shape of the dot landed on the recording paper and the formation position thereof become improper, and the image quality deteriorates. In order to prevent such a problem, in this type of recording apparatus, the above-described micro-vibration operation for slightly vibrating the meniscus, that is, the operation for slightly vibrating the meniscus to the extent that ink droplets are not ejected is performed. Then, the ink in the vicinity of the nozzle opening is agitated by this micro-vibration operation to prevent the viscosity of the ink from increasing.

This micro-vibration operation is performed, for example, by supplying a micro-vibration signal to a pressure generating element that causes a pressure fluctuation in the ink in the pressure chamber. Then, such a slight vibration operation is performed, for example, prior to the recording operation. Also,
Even during the recording operation, which is the ejection period of the ink droplets, it is performed for the nozzle openings that are not ejecting the ink droplets.

[0006]

By the way, the conditions for executing the micro-vibration operation (the conditions for stirring the liquid) are set on the basis of the conditions under which the thickening of the liquid is most likely to occur. That is, it is set so that normal recording can be performed even under the condition where the viscosity is most likely to increase. For example, in a liquid ejecting apparatus capable of ejecting three kinds of liquid droplets including a large liquid droplet, a medium liquid droplet, and a small liquid droplet, normal recording can be performed even when recording with a small liquid droplet that is most likely to thicken the liquid. As described above, the ink is sufficiently stirred.

However, when the stirring conditions are set in this way, the liquid is agitated excessively during the discharging operation using only the large droplets or during the discharging operation using the large droplets and the medium droplets. That is, when these droplets are ejected,
The liquid consumption is relatively large, and non-viscosified ink is supplied near the nozzle openings. Therefore, the droplets can be normally ejected even if the ink agitation is less than that during the ejection operation by the small droplets. If the liquid is agitated excessively, the pressure generating element is wastefully operated, which leads to an increase in power consumption and shortens the life of the pressure generating element.

The present invention has been made in view of such circumstances, while maintaining the state of the liquid in the vicinity of the nozzle openings satisfactorily, the liquid ejection equipment which can prevent wasteful minute vibration <br / > For the purpose of providing.

[0009]

The present invention has been proposed in order to achieve the above object, and the invention according to claim 1 causes a pressure fluctuation in the pressure chamber by the operation of the pressure generating element. A liquid ejecting head that ejects droplets from the nozzle opening due to this pressure fluctuation and a head scanning mechanism that moves the liquid ejecting head in the main scanning direction are provided, and a micro-vibration signal is supplied to the pressure generating element to generate a meniscus. In a liquid ejecting apparatus configured to agitate a liquid in the vicinity of a nozzle opening by a micro-vibration operation for micro-vibration, an output buffer for storing dot pattern data, and an output buffer for discharging liquid droplets in a unit scan prior to ejection operation. And a minimum liquid amount acquisition means for acquiring the minimum liquid amount of the liquid droplets ejected in the unit scan, based on the dot pattern data for each unit scan. And a stirring control means for optimizing the stirring conditions of the liquid in the micro-vibrating operation in accordance with the minimum liquid amount, the agitation拌制control means, the dot pattern data based on
Then, in the unit scan, the droplet discharge that first discharges the droplet is performed.
Obtain the starting point and wait for a specified distance from this starting point
The liquid ejecting apparatus is characterized in that the micro-vibration operation is performed under the optimized stirring condition from the position returned to the machine position side .

According to a second aspect of the present invention, the liquid ejecting head can eject a plurality of types of liquid droplets having different amounts from the same nozzle opening, and the minimum liquid amount acquiring means ejects in a unit scan. The liquid ejecting apparatus according to claim 1, wherein the smallest amount of liquid droplets among the plurality of liquid droplets is acquired as the minimum liquid amount.

According to a third aspect of the present invention, the stirring control means acquires liquid type information indicating the type of liquid to be ejected, and optimizes the stirring condition of the liquid in consideration of the type of liquid. The liquid ejecting apparatus according to claim 1 or 2.

According to a fourth aspect of the present invention, there is provided a storage cartridge for storing the liquid discharged from the nozzle opening, and a type information storage means provided in the storage cartridge for storing liquid type information regarding the stored liquid. 4. The type information reading unit for reading the liquid type information stored in the type information storage unit is provided, and the stirring control unit acquires the liquid type information through the type information reading unit. It is the described liquid ejecting apparatus.

According to a fifth aspect of the present invention, environmental information detecting means for detecting at least one of environmental temperature and environmental humidity as environmental information is provided, and the stirring control means considers the stirring conditions of the liquid in consideration of the environmental information. The liquid ejecting apparatus according to any one of claims 1 to 4, which is optimized.

The invention according to claim 6 is characterized in that the stirring control means optimizes the stirring condition of the liquid by increasing or decreasing the number of times of slight vibration. The liquid ejecting apparatus according to item 1.

The invention according to claim 7 is characterized in that the stirring control means optimizes the stirring condition of the liquid by changing the repetition period of the micro-vibration pulse constituting the micro-vibration signal. The liquid ejecting apparatus according to claim 6.

The invention according to claim 8 is characterized in that the stirring control means optimizes the stirring condition of the liquid by changing the amplitude of the micro-vibration pulse constituting the micro-vibration signal. The liquid ejecting apparatus according to claim 7 .

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. It should be noted that in the following description, an image recording apparatus that is one form of a liquid ejecting apparatus, specifically, an inkjet printer will be described as an example, but the present invention is a manufacturing apparatus, a textile printing apparatus, and an industry such as a micro dispenser. It can also be applied to machines.

The ink jet printer 1 shown in FIG.
(Hereinafter, referred to as a printer) is an ink cartridge 2 (2a, 2a that functions as a storage cartridge of the present invention.
b), a cartridge holder portion 3 as a cartridge holding means capable of holding the ink cartridge 2, and a carriage 5 to which a recording head 4 (a kind of liquid ejecting head) compatible with color recording is attached. The carriage 5 is provided with a temperature sensor 16 functioning as an environmental temperature detecting means and a humidity sensor 17 functioning as an environmental humidity detecting means. These sensors 16, 1
Both 7 function as environmental information detecting means of the present invention, and detect temperature and humidity around the recording head. In this embodiment, these sensors 16 and 17 are mounted on a printed circuit board (not shown) for supplying necessary electric signals to the piezoelectric vibrator 40 (see FIG. 3).

The carriage 5 has a housing 11
It is movably attached to guide members 6 erected on the left and right sides of and is reciprocated by a head scanning mechanism. The head scanning mechanism includes a step motor 7 attached to one end of the housing 11 on the left and right sides, a drive pulley 8 connected to a rotation shaft of the step motor 7, and an idle pulley 9 provided on the other end of the housing 11 on the left and right sides. , A timing belt 10 that is hung between the drive pulley 8 and the idle pulley 9 and connected to the carriage 5, and a printer controller 44 that controls the rotation of the step motor 7 (see FIG. 4).
(See) and the like. That is, this head scanning mechanism moves the carriage 5, that is, the recording head 4 back and forth in the width direction of the recording paper 12 by operating the step motor 7. The moving direction of the recording head 4 is the main scanning direction.

The printer 1 also has a paper feed mechanism for feeding the recording paper 12 in the paper feed direction. This paper feed mechanism is composed of a paper feed motor 13, a paper feed roller 14 and the like, and sequentially feeds the recording paper 12 in synchronism with the main scanning to perform sub scanning.

A home position and a standby position are set in an end region outside the recording region within the movement range of the carriage 5 (recording head 4). A cap member 1 for sealing the nozzle plate 28 (see FIG. 3) of the recording head 4 is provided below the home position.
5 is provided. The cap member 15 is an elastic member made of rubber or the like and is formed in a tray shape in which a recess is provided in the center of the upper surface of a substantially quadrangle, and a moisturizing material such as felt is attached to the inside of the recess. Therefore, by sealing the nozzle plate 28 of the recording head 4 with the cap member 15, the inside of the recess is kept at high humidity, and the evaporation of the ink solvent from the nozzle openings 25 is prevented.

As shown in FIG. 2, the home position of the carriage 5 (recording head 4) is set at the end of the movement range guided by the guide member 6, and the standby position is located closer to the recording area than the home position. Set next to each other.

The home position is a position where the recording head 4 is positioned when the power is off or recording is not performed for a long time. When the recording head 4 is located at this home position, the above-mentioned cap member 15 is pressed against the nozzle plate 28 to seal the nozzle opening 25.
Further, the standby position is a position serving as a scanning starting point when the recording head 4 is main-scanned. That is, normally, the recording head 4 stands by at this standby position, is moved from the standby position to the recording area side during the recording operation, and is returned to the standby position when the recording operation is completed. An acceleration area is set between the standby position and the recording area. This acceleration area is an area for accelerating the scanning speed of the recording head 4 to a predetermined speed, and a slight vibration operation prior to the recording operation is performed in this acceleration area.

Next, the structure of the recording head 4 will be described. In the illustrated recording head 4, as shown in FIG. 3, the flow path unit 22 is joined to the front end surface of the case 21. The vibrator unit 23 housed inside the case 21
The pressure chamber 24 in the flow path unit 22 is caused to fluctuate to eject ink droplets from the nozzle openings 25.

The case 21 is a box-shaped body in which a housing chamber 26 for housing the transducer unit 23 is formed, and is made of, for example, a resin material. The accommodating chamber 26 provided in the case 21 is continuous from the opening on the joint surface side with the flow path unit 22 to the opposite surface.

The flow path unit 22 has a structure in which the nozzle plate 28 is joined to one surface of the spacer 27 and the diaphragm 29 is joined to the other surface of the spacer 27. Spacer 27
Is formed of a silicon wafer or the like, and is divided into a predetermined pattern by etching the silicon wafer, and a plurality of pressure chambers 24 communicating with the nozzle openings 25 are formed.
The common ink chamber 31, the common ink chamber 31 to each pressure chamber 24
A partition wall forming a plurality of ink supply paths 32 and the like connected to is properly formed. The common ink chamber 31 is provided with a connection port connected to the ink supply pipe 33, and the ink stored in the ink cartridge 2 is supplied to the common ink chamber 31 through this connection port.

The nozzle plate 28 has a plurality of nozzle openings 25 formed in rows at a pitch corresponding to the dot formation density, and these nozzle openings 25 form a nozzle row. This nozzle row is
That is, it is formed in the sub-scanning direction.

The vibration plate 29 consists of a stainless steel plate 35 and a PPS.
The elastic film 36 such as a film is laminated to form a double structure, and the portion corresponding to each pressure chamber 24 is annularly etched on the stainless steel plate 35 side to form an island portion 37 in the ring.

The vibrator unit 23 is composed of a piezoelectric vibrator 40 which is a kind of pressure generating element and a fixed substrate 41. The piezoelectric vibrator 40 is formed by forming slit portions on a single piezoelectric vibrator plate in which piezoelectric bodies and electrode layers are alternately laminated at a predetermined pitch corresponding to each pressure chamber 24 of the flow path unit 22. It is formed like a tooth. In addition, the fixed substrate 4
1 is fixed to the base end portion of the comb-shaped oscillator. The vibrator unit 23 is inserted into the housing chamber 26 of the case 21 with the tip of the piezoelectric vibrator 40 facing the opening, and is fixed to the case 21 by fixing the fixed substrate 41 to the inner wall of the housing chamber 26. In this attached state,
Each tip of the piezoelectric vibrator 40 is fixed to the corresponding island portion 37 of the diaphragm 29.

Each piezoelectric vibrator 40 expands and contracts in the element longitudinal direction orthogonal to the stacking direction by applying a potential difference between the electrodes facing each other, and displaces the elastic film 36 partitioning the pressure chamber 24. That is, in this recording head 4, the piezoelectric vibrator 4
By extending 0 in the element longitudinal direction, the island portion 37 is pushed toward the nozzle plate 28 side, the elastic film 36 around the island portion is deformed, and the pressure chamber 24 contracts.
When the piezoelectric vibrator 40 is reduced in the element longitudinal direction,
The displacement of the elastic film 36 causes the pressure chamber 24 to expand. Then, as the volume of the pressure chamber 24 changes, the pressure chamber 2
Since pressure fluctuation occurs in the ink filled in the nozzle 4, the nozzle opening 2 is controlled by controlling the volume change of the pressure chamber 24.
Ink droplets can be ejected from 5.

In this embodiment, the recording head 4 is configured for color recording capable of ejecting a plurality of different colors. That is, the nozzle plate 28 is provided with a plurality of nozzle rows (for example, four rows) in the main scanning direction, and the pressure chamber 24, the transducer unit 23, and the like are configured in correspondence with each of these nozzle rows. Provide each element. Then, the black ink cartridge 2a that stores black ink and the color ink cartridge 2b that individually stores each ink of yellow ink, magenta ink, and cyan ink are attached to the cartridge holder portion 3, and ink of each color is attached. Printing is performed by ejecting from the corresponding nozzle row.

These black ink cartridges 2
The control IC 18 (see FIG. 4) is mounted on each of the a and the color ink cartridge 2b. The control IC 18 is a kind of the type information storage means of the present invention and stores ink type information indicating the type of ink stored in the cartridge. That is, the liquid type information indicating the type of the stored liquid is stored. The ink type information includes identification information indicating the type of liquid (hereinafter referred to as ID information), for example, information indicating the type of coloring material (pigment) used, the color of ink, and the like. Therefore, in the control IC 18 of the black ink cartridge 2a,
ID information indicating a dye-based black ink or a pigment-based black ink is stored. In the control IC 18 of the color ink cartridge 2b, the first block = dye-based yellow ink, the second block = dye-based magenta ink, and the third block = dye-based cyan ink are stored. ID information indicating information such as the type of color material for ink and the color of ink is stored.

Along with this, the information reading terminal 19 which is electrically connected to the control IC 18 in the state where the ink cartridge 2 is mounted in the cartridge holder portion 3.
(See FIG. 4). The information reading terminal 19 is a kind of the kind information reading means in the present invention, and is a control I
This is a terminal for reading the ink type information stored in C18. The information reading terminal 19 is electrically connected to the controller 49 of the printer controller 44, and the controller 49 acquires the ink type information (ID information) through the information reading terminal 19.

Next, the electrical configuration of the printer 1 will be described. As shown in FIG. 4, the printer 1 includes a printer controller 44 and a print engine 45.

First, the printer controller 44 will be described. The printer controller 44 is an interface 46 (hereinafter, referred to as an external I / F 46) that receives various data from a host computer (not shown) or the like.
A RAM 47 for temporarily storing various data, a ROM 48 for storing a control program, a control unit 49 including a CPU, an oscillator circuit 50 for generating a clock signal, and a piezoelectric vibration of the recording head 4. A drive signal generation circuit 51 for generating a drive signal COM and a micro-vibration signal VS to be supplied to the child 40, and an interface 52 for transmitting the dot pattern data developed based on the print data, the drive signal COM, etc. to the print engine 45. (Hereinafter referred to as internal I / F 52) and the like.

The external I / F 46 receives print data composed of, for example, a character code, a graphic function, image data, etc. from the host computer or the like. In addition, the busy signal (B
USY) or an acknowledge signal (ACK) is output to the host computer or the like.

The RAM 47 functions as a reception buffer, an intermediate buffer, an output buffer and a work memory (not shown). Then, the reception buffer temporarily stores the print data received via the external I / F 46, the intermediate buffer stores the intermediate code data, and the output buffer stores the dot pattern data.

The ROM 48 stores a control program (control routine) for performing various data processing, font data, graphic functions and the like. The ROM 48 also stores various setting data for maintenance operation for performing maintenance of the recording head 4.

The control section 49 performs various controls in the printer 1. For example, control is performed to control a printing operation such as developing print data received from a host computer or the like into dot pattern data, or to control a micro-vibration operation performed for each main scanning (unit scanning).

The control unit 49 reads the print data in the reception buffer and stores the intermediate code data obtained by converting the read print data in the intermediate buffer during the expansion operation of the print data into the dot pattern data. Then, the intermediate code data read from the intermediate buffer is analyzed and developed into dot pattern data by referring to the font data and the graphic function stored in the ROM 48. Then, the developed dot pattern data is subjected to necessary decoration processing, and the dot pattern data after this decoration processing is stored in the output buffer.

The data of each dot (1 pixel) in the dot pattern data is composed of 3-bit print data. This print data is a kind of drive data of the present invention, and is a selection signal for selecting drive pulses (DP1 to DP3) from a drive signal COM (see FIG. 5) described later. The print data will be described later.

When the dot pattern data for one main scan (that is, one line) has been developed, the control unit 49 outputs the dot pattern data for one line from the output buffer to the internal I. The data is sequentially transmitted to the electric drive system 39 of the recording head 4 through / F52, and the carriage 5 is moved in synchronization with this transmission to perform printing for a unit scan.
When one line of dot pattern data is output from the output buffer, the expanded intermediate code data is erased from the intermediate buffer, and expansion processing is performed on the next intermediate code data.

Further, in relation to the micro-vibration operation performed for each unit scan, the control section 49 functions as the minimum liquid amount acquisition means of the present invention, and controls a plurality of ink droplets ejected in one main scan. A minimum ink amount (corresponding to the minimum liquid amount of the present invention), which is the smallest amount of ink droplets, is acquired from the inside. In the present embodiment, the minimum ink amount is obtained based on the dot pattern data described above, that is, by referring to the print data of each dot forming one line. When the minimum ink amount is acquired, the control unit 49 functions as the agitation control unit of the present invention, and optimizes the ink agitation condition based on the acquired minimum ink amount. Regarding this slight vibration operation,
More on this later.

The drive signal generation circuit 51 functions as drive signal generation means and generates a drive signal COM in which a plurality of drive pulses for ejecting a plurality of types of ink droplets having different amounts are arranged in time series. . Then, during the recording operation, this drive signal COM is output to the electric drive system 39 of the recording head 4 via the internal I / F 52.

As shown in FIG. 5, the drive signal COM of this embodiment has the first drive pulse D within the predetermined print cycle T0.
P1, the second drive pulse DP2, and the third drive pulse D
It is a signal in which P3 is arranged in series in this order. The printing cycle T0 is a set time for recording one dot, and is a basic timing for synchronization in the recording operation (main scanning). Then, as will be described later, the printing cycle T0
Drive pulses DP1, DP2, D arranged within the period
By appropriately selecting P3 and supplying it to the piezoelectric vibrator 40, it is possible to eject different amounts of ink droplets from the same nozzle opening 25. That is, a small ink droplet (corresponding to a small droplet), a medium ink droplet (corresponding to a medium droplet), or a large ink droplet (corresponding to a large droplet) can be ejected.

Further, the drive signal generating circuit 51 also functions as a micro-vibration signal generating means, generates the micro-vibration signal VS for performing the micro-vibration operation at the time of the micro-vibration operation for each unit scan, and drives the recording head 4. Output to the electric drive system 39. As shown in FIG. 6, the micro-vibration signal VS is configured by arranging trapezoidal micro-vibration pulses DP0 repeatedly generated in a cycle T1 in time series. Then, the drive signal generation circuit 51 is controlled by the control unit 49 as a stirring control means, and generates the micro-vibration signal VS in which the amplitude h of the micro-vibration pulse DP0 and the generation period T1 are set to optimum values. In the micro-vibration signal VS, the amplitude h of the micro-vibration pulse DP0 and the potential gradient θ are set to the extent that ink droplets are not ejected, so that the pressure chamber 24 slightly expands and contracts when applied to the piezoelectric vibrator 40. The meniscus of the nozzle opening 25 vibrates slightly. As a result, the ink near the nozzle openings is agitated.

The print engine 45 includes a step motor 7, a paper feed motor 13, an electric drive system 39 for the recording head 4, and the like. Electric drive system 39 of recording head 4
Has a shift register 54, a latch circuit 55, a level shifter 56, a switch 57, and a piezoelectric vibrator 40, and has a circuit configuration in which these are sequentially connected. A plurality of the shift register circuits 54, the latch circuits 55, the level shifter circuits 56, and the switch circuits 57 are provided corresponding to the piezoelectric vibrators 40 ...

The recording head 4 ejects a plurality of types of ink droplets having different ink amounts based on the dot pattern data sent from the printer controller 44 to the electric drive system 39. That is, a plurality of types of droplets having different amounts are ejected.

That is, the dot pattern data (SI) is
In synchronization with the clock signal (CK) from the oscillation circuit 50,
It is serially transmitted to the shift register 54 through the internal I / F 52. The dot pattern data transmitted serially is once latched by the latch circuit 55.
The latched dot pattern data is boosted to a voltage capable of driving the switch 57 by the level shifter 56 which is a voltage amplifier. The boosted data is stored in switch 5
7 is supplied. The drive signal COM from the drive signal generation circuit 51 is input to the input side of the switch 57, and the piezoelectric vibrator 40 is connected to the output side of the switch 57.

The print data forming the dot pattern data controls the operation of the switch 57. For example, while the print data applied to the switch 57 is “1”, the drive signal COM generated by the drive signal generation circuit 51 is supplied to the piezoelectric vibrator 40, and the piezoelectric vibrator 40 responds to the drive signal COM. Deform. On the other hand, while the print data applied to the switch 57 is “0”, the supply of the drive signal to the piezoelectric vibrator 26 is cut off.

In the present embodiment, the piezoelectric transducer 4 selectively selects the drive pulses DP1, DP2, DP3 included in the drive signal COM according to the content of the 3-bit print data.
Supply to 0. That is, the print data (D1, in which the most significant bit D1 is associated with the first drive pulse DP1, the second bit D2 is associated with the second drive pulse DP2, and the least significant bit D3 is associated with the third drive pulse DP3. D2, D
3) is used to transmit the dot pattern data composed of this print data to the recording head 4, whereby the drive pulses DP1, DP2, DP3 are selectively supplied to the piezoelectric vibrator 40.

For example, when a small ink droplet (for example, an ink droplet of about 3 pL (picoliter)) capable of forming a microdot is ejected from the nozzle opening 25, the print data is D1 = 0, D2 = 1. , D3 = 0 and the second
The drive pulse DP2 is selectively supplied to the piezoelectric vibrator 40. When ejecting a medium ink droplet (for example, an ink droplet of about 6 pL) capable of forming a middle dot from the nozzle opening 25, print data D1 = 1, D2 =
0 and D3 = 1 are set, and the first drive pulse DP1 and the third drive pulse DP3 are selectively supplied to the piezoelectric vibrator 40.
Similarly, when a large ink droplet (for example, an ink droplet of about 13 pL) that can form a large dot is ejected from the nozzle opening 25, the print data is D1 = 0, D2 = 1,
D3 = 1 is set, and the second drive pulse DP2 and the third drive pulse DP3 are selectively supplied to the piezoelectric vibrator 40. Furthermore, when performing a micro-vibration operation during printing operation,
Set the print data to D1 = 1, D2 = 0, D3 = 0,
The first drive pulse DP1 is selectively supplied to the piezoelectric vibrator 40.

Next, the micro-vibration operation for each unit scan performed prior to the recording operation will be described. In this embodiment,
This slight vibration operation is performed in the acceleration region shown in FIG.
Hereinafter, the microvibration operation performed in this acceleration region will be referred to as non-printing microvibration.

In this out-of-print microvibration, the control section 49 (minimum liquid amount acquisition means, that is, minimum ink amount acquisition means in the image recording apparatus) first develops one line (that is, unit scanning) developed in the output buffer. Min) dot pattern data, and the minimum amount of ink droplets among the plurality of ink droplets ejected in this one line is acquired as the minimum ink amount. For example, 3 consisting of large ink drops, medium ink drops, and small ink drops
In the printer 1 capable of ejecting various types of ink drops, the control unit 4
9 determines whether the smallest amount of ink droplets is a small ink droplet, a medium ink droplet, or a large ink droplet, and acquires the determination result as the minimum ink amount.

That is, when the print data (010) for ejecting small ink droplets is included in the dot pattern data for one line, the minimum ink amount is determined to be the amount of small ink droplets. Similarly, print data (011) for ejecting a large ink drop and print data (10 for ejecting a medium ink drop).
If the dot pattern data consists of 1) and
Alternatively, when the dot pattern data is composed only of print data for ejecting medium ink droplets, the minimum ink amount is determined to be the amount of medium ink droplets. Then, when the dot pattern data is configured only by the print data for ejecting the large ink droplet, the minimum ink amount is determined to be the amount of the large ink droplet.

When the minimum ink amount is obtained in this way, the control unit 49 (stirring control means) optimizes the stirring condition of the ink in the micro-vibration operation. This agitation condition has the number of times of the micro-vibration pulse DP0 supplied, the generation period T1, and the amplitude h as parameters, and the standard condition is that the minimum ink amount is a medium ink drop amount. Under this reference condition, for example, the number of times the minute vibration pulse DP0 is supplied is set to 250
The generation cycle T1 is set to 46.3 microseconds, and the amplitude h is set to 40% of the maximum amplitude H (see FIG. 5) in the drive signal COM.

When the minimum ink amount is smaller than the reference condition, it is considered that the ink consumption is small and the ink thickening in the vicinity of the nozzle opening is more likely to proceed than under the reference condition. The meniscus is vibrated greatly, the vibration cycle is lengthened, and the frequency of the meniscus is increased. For example, when the minimum ink amount is the amount of small ink droplets, the number of times the micro-vibration pulse DP0 is supplied is set to 1.
5 times (coefficient 1.5) is set to 375 times, and the generation cycle T1
Is set to 92.6 microseconds, which is twice the reference condition, and the amplitude h is set to 60% of the maximum amplitude H. It has been experimentally confirmed that vibrating the meniscus in such a manner can efficiently stir the thickened ink when the minimum ink amount is smaller than the reference condition.

On the other hand, when the minimum ink amount is larger than the reference condition, the ink consumption is large and the increase in the viscosity of the ink near the nozzle opening is less likely to proceed than in the reference condition. , Lower the frequency than the standard condition. For example, when the minimum ink amount is the large ink drop amount,
The number of times the minute vibration pulse DP0 is supplied is appropriately set within the range of 108 to 250 times.

When the stirring conditions are set in this way, the control unit 49 (stirring control means) supplies the microvibration signal VS to the piezoelectric vibrator 40.

As shown in an example in FIG. 7, the control unit 49
First, the drive signal generation circuit 51 (drive signal generation means) is controlled so that the recording head 4 waits at the standby position for the minute vibration signal VS in which the generation period T1 of the minute vibration pulse DP0 and the amplitude h are set. It is generated from the point of time (t0).
Next, the control unit 49 sets the print data DV1 (see FIG. 6) in which “1” is set for all the piezoelectric vibrators 40 ... In the shift register 54. When the print data DV1 is set, the control unit 49 causes the latch signal (LAT)
To the latch circuit 55 to latch the print data DV1 (t1 ′). By latching the print data DV1, the microvibration signal VS is supplied to all the piezoelectric vibrators 40, and the microvibration of the meniscus starts at each nozzle opening 25. Then, after the print data DV1 is latched, the control unit 49 sets the print data DV0 in which “0” is set for all the piezoelectric vibrators 40 ... In the shift register 54.

Further, the control section 49 operates the step motor 7 to start the movement of the recording head 4 (carriage 5) in the main scanning direction (t1). Then, when the microvibration pulse DP0 of the set number of times is supplied to the piezoelectric vibrator 40, the control unit 49 outputs a latch signal to the latch circuit 55 at the timing (t2 ′) as shown in FIG. ,
The print data DV0 is latched. When the print data DV0 is latched, the supply of the slight vibration signal VS to the piezoelectric vibrator 40 is cut off. After that, the control unit 49 controls the drive signal generation circuit 51 to stop the generation of the micro-vibration signal VS and to output the drive signal COM at the timing (t2) immediately before the scanning speed of the recording head 4 reaches the predetermined speed. generate.

As described above, in the above-described non-printing slight vibration, 1
The waveform shape of the micro-vibration signal VS is set and optimized according to the minimum amount of ink droplets recorded in one main scan, and necessary and sufficient ink agitation is performed without excess or deficiency. Therefore, unnecessary fine vibration can be prevented while maintaining a good ink state near the nozzle openings, which contributes to extending the life of the piezoelectric vibrator 40 and reducing the power consumption of the printer 1.

By the way, the easiness of thickening of the ink varies depending on the amount of the ejected ink droplets (that is, the ink consumption amount) as described above, but the environment in which the printer 1 is installed is different. Temperature and humidity, especially the temperature and humidity in the vicinity of the recording head 4, and also the type of ink used.

Therefore, in addition to the information indicating the minimum ink amount, the information indicating the temperature of the installation environment (atmosphere), the information indicating the humidity of the installation environment, and the information indicating the type of ink are fetched, and these information are acquired. If the stirring conditions of the ink are optimized in consideration of the above, the micro-vibration operation can be performed under more optimal stirring conditions.

In this case, the control unit 49 (stirring control means)
Recognizes the ambient temperature of the recording head 4 as the environmental temperature based on the detection information from the temperature sensor 16 (environmental temperature detecting means), and when the environmental temperature is higher than the reference temperature (for example, room temperature), the minimum ink The stirring condition determined based on the amount is corrected to increase the number of times the micro-vibration pulse DP1 is supplied and lengthen the generation cycle T1 of the micro-vibration pulse DP1. Conversely,
When the environmental temperature is equal to or lower than the reference temperature, the stirring condition determined based on the minimum ink amount is used as it is.
In short, the control unit 49 determines that the higher the recognized environmental temperature, the easier the ink viscosity increases, and the lower the environmental temperature, the more difficult the ink viscosity increases.

Similarly, the controller 49 controls the humidity sensor 17
The ambient humidity of the recording head 4 is recognized as the environmental humidity on the basis of the detection information from the (environmental humidity detection means), and when the environmental humidity is lower than the reference humidity, the stirring condition determined based on the minimum ink amount is set. The correction is performed to increase the number of times the minute vibration pulse DP1 is supplied and lengthen the generation cycle T1 of the minute vibration pulse DP1. On the contrary, when the environmental humidity is equal to or higher than the reference humidity, the stirring condition determined based on the minimum ink amount is used. In short, the control unit 49 determines that the lower the recognized environmental humidity, the easier the ink viscosity increases, and the higher the environmental humidity, the more difficult the ink viscosity increases.

The control section 49 also recognizes the type of ink being used based on the ink type information stored in the control IC 18 mounted on the ink cartridge 2.
Here, the pigment-based ink using a pigment as a color material,
It has a characteristic that it is more likely to thicken than a dye-based ink using a dye as a coloring material. Even if the dye-based inks or the pigment-based inks are used together, the black ink is more likely to thicken than the dark color inks such as the cyan ink and the magenta ink, and the dark color inks are the yellow ink, the light cyan ink, and the light magenta ink. It has a characteristic that it is more easily thickened than light-colored inks such as. Therefore, the degree of easiness of thickening is weighted for each ink type (that is, for each ID information), and the number of times of supplying the microvibration pulse DP1 increases as the viscosity of the ink increases, and the generation period T1 of the microvibration pulse DP1 increases. The coefficient is set so that it becomes longer and the amplitude h of the micro-vibration pulse DP1 becomes larger.

As described above, by optimizing the ink stirring conditions by taking into consideration the temperature and humidity in the installation environment and the type of ink, it is possible to perform a more vibrant microvibration operation, and the piezoelectric vibrator. This contributes to further prolonging the life of the battery 40 and further reducing the power consumption.

By the way, the present invention is not limited to the above embodiment, but various modifications can be made within the scope described in the claims.

For example, the present invention can be applied to a micro-vibration operation (micro-vibration before printing) which is performed immediately before ink droplets are actually ejected for recording. In this case, the control unit 49
On the basis of the developed dot pattern data, obtains the recording start point (for example, the position indicated by reference symbol P1 in FIG. 7) at which the ink droplet is first ejected in the unit scan, and moves from the recording start point to the standby position side by a predetermined distance L1. Returned position P2
Is the starting point of the slight vibration. Then, from the time when the recording head 4 reaches the slight vibration start point, the slight vibration operation is performed under the optimized stirring condition in the same manner as in the above embodiment.
With this configuration, since the micro-vibration operation is performed immediately before actually ejecting the ink droplet, it is possible to more reliably prevent the thickening of the ink.

In the above embodiment, the control unit 49 (stirring control means) determines the stirring condition of the ink based on the presence or absence of the small ink droplets forming the small dots. It may be configured such that the stirring condition is determined in consideration. For example, the proportion of small ink droplets in all the ink droplets ejected in one unit scan is obtained based on the dot pattern data. If this proportion is higher than the reference value, the increase in ink viscosity It is determined that it is easy to perform, the number of times of supplying the micro-vibration pulse DP1 is increased, the generation period T1 of the micro-vibration pulse DP1 is lengthened, and the amplitude h of the micro-vibration pulse DP1 is set to be larger than the reference condition. Conversely,
If the ratio of small ink droplets is lower than the standard value,
It is determined that it is difficult to increase the viscosity of the ink, and the number of times the micro-vibration pulse DP1 is supplied is reduced compared to the reference condition.

In the above embodiment, the ink agitation condition is determined based on the dot pattern data of the unit scan to be performed, but this time based on the information of the ink droplet ejected in the previous unit scan. It is also possible to control the micro-vibration operation (micro-vibration outside printing or micro-vibration before printing) in the unit scanning. In this case, the minimum ink amount in the previous unit scan can be acquired in advance when developing the dot pattern data in the previous unit scan, and can be acquired even by measuring the actually ejected ink amount. You can

Further, as the pressure generating element for causing the pressure fluctuation in the pressure chamber 24, a heating element, a magnetostrictive element or the like can be used in addition to the piezoelectric vibrator 40.

Further, the present invention is not limited to the image recording apparatus such as the printer 1 or the plotter or the facsimile, but may be applied to the liquid ejecting apparatus having the liquid ejecting head for ejecting the droplet from the nozzle opening. it can. For example, it can be applied to manufacturing machines, textile printing machines, and industrial machines such as microdispensers.

[0075]

As described above, the present invention has the following effects. That is, an output buffer that stores dot pattern data, and a minimum liquid amount acquisition unit that acquires the minimum liquid amount of a droplet discharged in a unit scan based on the dot pattern data for the unit scan stored in the output buffer. And a stirring control means for optimizing the stirring conditions of the liquid in the micro-vibration operation according to the acquired minimum liquid amount,
The agitation control unit determines whether the
In the position scan, the droplet discharge starting point that first discharges the droplet is set.
The standby position for a predetermined distance from the droplet discharge start point.
Since the micro-vibration operation is performed under optimized stirring conditions from the position returned to the nozzle side, sufficient and sufficient liquid stirring can be performed according to the ease of thickening of the liquid near the nozzle opening. Be seen. Therefore, it is possible to prevent unnecessary micro-vibration while maintaining a good state of the liquid near the nozzle opening, which contributes to prolonging the life of the pressure generating element and reducing the power consumption of the liquid ejecting apparatus. Also, actually eject ink drops
Since the micro-vibration operation is performed immediately before,
Can be prevented more reliably.

Further, the minimum amount of liquid can be easily obtained without adding a special mechanism, which contributes to simplification of the device configuration.

When liquid type information indicating the type of liquid to be ejected is acquired and the stirring conditions of the liquid are optimized by considering the type of liquid, for example, dye-based ink or pigment-based ink is used. Even if a plurality of types of liquids having different viscosities such as ink are used, the micro-vibration operation can be performed under appropriate stirring conditions suitable for the liquids.

Further, when the storage cartridge is provided with type information storage means for storing the liquid type information about the stored liquid, and the liquid type information stored in the type information storage means is acquired through the type information reading means. Has
The type of ink can be automatically recognized without requiring any special operation, and the operation can be simplified.

Further, an environmental information detecting means for detecting at least one of environmental temperature and environmental humidity as environmental information is provided,
When it is configured to optimize the stirring conditions of the liquid in consideration of the environmental information, the micro-vibration operation can be performed under the stirring conditions suitable for the installation environment of the recording apparatus .

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of an inkjet printer.

FIG. 2 is a diagram illustrating a moving range of a recording head in main scanning.

FIG. 3 is a cross-sectional view showing a configuration of a recording head.

FIG. 4 is a block diagram showing an electrical configuration of the printer.

FIG. 5 is a timing diagram showing a relationship between a drive signal COM and a drive pulse.

FIG. 6 is a timing diagram showing a slight vibration signal VS.

FIG. 7 is a timing diagram illustrating a recording operation.

[Explanation of symbols]

1 Inkjet printer 2 ink cartridge 3 Cartridge holder 4 recording head 5 carriage 6 Guide member 7 step motor 8 drive pulley 9 Idler pulley 10 Timing belt 11 housing 12 Recording paper 13 Paper feed motor 14 Paper feed roller 15 Cap member 16 Temperature sensor 17 Humidity sensor 18 Control IC 19 Information reading terminal 21 cases 22 Channel unit 23 Transducer unit 24 Pressure chamber 25 nozzle opening 26 accommodation room 27 spacer 28 nozzle plate 29 diaphragm 31 common ink chamber 32 ink supply path 33 Ink supply pipe 35 stainless steel plate 36 Elastic Membrane 37 Island 39 Electric drive system 40 Piezoelectric vibrator 44 Printer controller 45 print engine 46 External interface 47 RAM 48 ROM 49 control unit 50 oscillation circuit 51 Drive signal generation circuit 52 Internal interface 54 shift register circuit 55 Latch circuit 56 level shifter circuit 57 switch circuit

─────────────────────────────────────────────────── --- Continuation of the front page (56) References Japanese Patent Laid-Open No. 10-81012 (JP, A) Japanese Patent Laid-Open No. 10-81013 (JP, A) Japanese Patent Laid-Open No. 9-30007 (JP, A) Japanese Patent Laid-Open No. 10- 6526 (JP, A) JP 9-201960 (JP, A) JP 10-6527 (JP, A) JP 7-144419 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B41J 2/175 B41J 2/205

Claims (8)

(57) [Claims] 1. A liquid ejecting head for causing a pressure fluctuation in a pressure chamber by the operation of a pressure generating element, and ejecting a liquid droplet from a nozzle opening by the pressure fluctuation, and a head scanning for moving the liquid ejecting head in a main scanning direction. And a mechanism for supplying a microvibration signal to the pressure generating element to microvibrate the meniscus to agitate the liquid in the vicinity of the nozzle opening, and an output buffer for storing dot pattern data. And the minimum liquid volume for acquiring the minimum liquid volume of the droplets ejected in the unit scan based on the dot pattern data for the unit scan stored in the output buffer prior to the droplet ejection operation in the unit scan. And a stirring control means for optimizing the stirring conditions of the liquid in the micro-vibration operation according to the acquired minimum liquid amount. Control means, based on the dot pattern data
, The first droplet ejection in the unit scan
Point, and wait for a predetermined distance from the droplet discharge start point.
A liquid ejecting apparatus, wherein the micro-vibration operation is performed under the agitating condition optimized from the position returned to the motion side. 2. The liquid ejecting head is capable of ejecting a plurality of types of liquid droplets having different amounts from the same nozzle opening, and the minimum liquid amount acquisition means is one of a plurality of liquid droplets ejected in a unit scan. The liquid ejecting apparatus according to claim 1, wherein the smallest amount of the liquid droplet is acquired as the minimum liquid amount. 3. The stirring control means obtains liquid type information indicating the type of liquid to be ejected, and optimizes the stirring condition of the liquid in consideration of the type of liquid. The liquid ejecting apparatus according to claim 2. 4. A storage cartridge for storing a liquid discharged from a nozzle opening, a type information storage means provided in the storage cartridge for storing liquid type information about the stored liquid, and a storage in the type information storage means. 4. The liquid ejecting apparatus according to claim 3, further comprising: a type information reading unit for reading the stored liquid type information, wherein the stirring control unit acquires the liquid type information through the type information reading unit. 5. An environmental information detecting means for detecting at least one of environmental temperature and environmental humidity as environmental information is provided, and the stirring control means optimizes the stirring conditions of the liquid in consideration of the environmental information. Claims 1 to 4
The liquid ejecting apparatus according to any one of 1. 6. The liquid ejecting apparatus according to claim 1, wherein the stirring control unit optimizes the stirring condition of the liquid by increasing or decreasing the number of times of slight vibration. 7. The stirring control means optimizes the stirring condition of the liquid by changing the repetition period of the micro-vibration pulse forming the micro-vibration signal.
7. The liquid ejecting apparatus according to claim 6. 8. The stirring control means optimizes the stirring condition of the liquid by changing the amplitude of the micro-vibration pulse forming the micro-vibration signal. The liquid ejecting apparatus described .