JP2011000819A - Fluid jetting apparatus and operating method thereof - Google Patents

Abstract

The present invention provides a fluid ejecting apparatus and an operation method capable of preventing white ink ejection failure due to changes in printing time, environmental temperature, and the like.
An ink jet printer according to the present invention acquires a recording head having a plurality of nozzle rows L2 to L9 that eject color ink, a nozzle row L1 that ejects white ink or clear ink, and the state of white ink. And a selector 50 that selectively switches either white ink or clear ink to supply to the recording head 3 based on the information of the white ink acquired by the fluid information acquisition unit. Yes.
[Selection] Figure 5

Description

  The present invention relates to a fluid ejecting apparatus and an operation method thereof.

  The fluid ejecting apparatus is an apparatus that includes an ejecting head capable of ejecting a fluid and ejects various fluids from the ejecting head toward a recording material or the like. As a typical fluid ejecting apparatus, for example, an ink jet ejecting head (hereinafter simply referred to as an ejecting head) is provided, and liquid ink (fluid) is ejected from the nozzles of the ejecting head (ejection head) as a recording medium. 2. Description of the Related Art Inkjet recording apparatuses that perform recording by forming dots by jetting and landing on a recording medium such as the above are known.

  In the fluid ejecting apparatus, maintenance such as a flushing process and a suction process is periodically performed in order to maintain or recover a good ejecting state of the fluid ejected from the ejecting head. Of the inks used as the image forming liquid, the white ink, in particular, has a larger particle size than the other color inks and is likely to be clogged. For this reason, the number of times of cleaning increases and the amount of ink consumed increases.

  Therefore, by selectively filling white ink and clogging prevention liquid into the nozzle row that ejects white ink of the recording head, the occurrence of clogging can be prevented and the number of cleanings can be reduced. There is known a technique capable of performing (Patent Document 1).

JP 2008-162023 A

  However, since the state change (thickening, etc.) of the white ink accompanying changes in the printing time and environmental temperature is not taken into consideration, the white ink left in the color printing mode is thickened. There was a risk of ejection failure in the white printing mode.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a fluid ejecting apparatus and an operation method thereof that can prevent ejection failure associated with a change in the state of a non-use fluid. It is one.

  In order to solve the above-described problem, the fluid ejecting apparatus of the present invention has a plurality of first nozzle arrays that eject the first fluid and a fluid ejecting apparatus that includes the second nozzle array that ejects the second fluid or the functional liquid. Based on the information of the head, the fluid information acquisition unit that acquires the state of the second fluid, and the second fluid acquired by the fluid information acquisition unit, either the second fluid or the functional fluid is selectively selected And a switching device that switches to supply to the fluid ejecting head.

  According to the present invention, it is possible to constantly monitor the state change of the second fluid supplied to the fluid ejecting head, including during the recording of the first fluid. Based on the state of the second fluid, either the second fluid or the functional liquid is selectively switched and supplied to the fluid ejecting head, thereby preventing ejection failure during recording with the second fluid. Can do.

In addition, the fluid information acquisition unit includes a temperature sensor that measures the temperature of the second fluid, and the switching device selects either the second fluid or the functional liquid based on the temperature of the second fluid acquired by the temperature sensor. It is preferable to selectively switch between.
According to the present invention, it is possible to prevent a discharge failure due to a rise in environmental temperature or a rise in temperature of the second fluid.

In addition, the fluid information acquisition unit can form an electric field between the nozzle plate in which the first nozzle row and the second nozzle row are formed and the fluid receiving unit that is disposed to face the nozzle plate in a non-contact state Preferably, the switching device selectively switches either the second fluid or the functional liquid based on the discharge amount of the second fluid acquired by the fluid information acquisition unit.
According to the present invention, the state change is monitored by detecting the discharge amount of the second fluid, and when it is detected that the discharge amount of the second fluid has decreased, the function fluid is switched. It is possible to prevent the ejection failure at the time of recording with the second fluid.

Moreover, it is preferable to have a time measuring part which time-measures the time when the 2nd fluid was supplied to the fluid ejecting head.
According to the present invention, since the time measuring unit that measures the time during which the second fluid is supplied to the fluid ejecting head is provided, drying of the second fluid from the second nozzle during non-ejection is prevented. Can do.

  In order to solve the above-described problem, the fluid ejecting apparatus of the present invention has a plurality of first nozzle arrays that eject the first fluid and a fluid ejecting apparatus that includes the second nozzle array that ejects the second fluid or the functional liquid. A head, a reservoir for storing a second fluid and a functional liquid, and a fluid ejecting head and a reservoir, and selectively switching either the second fluid or the functional liquid to the fluid ejecting head. And a switching device that supplies the fluid ejecting head by selectively switching either the second fluid or the functional liquid according to the thickened state of the second fluid. And

  According to the present invention, it is possible to monitor the thickened state of the second fluid while ejecting the first fluid, and supply to the fluid ejecting head based on the thickened state of the second fluid. By switching to the functional liquid, it is possible to prevent the discharge failure of the second fluid.

  In order to solve the above-described problem, an operation method of a fluid ejecting apparatus according to the present invention includes a plurality of first nozzle arrays that eject a first fluid and a second nozzle array that ejects a second fluid or a functional liquid. A fluid ejection head, a fluid information acquisition unit that acquires a state of the second fluid, and a second fluid and a functional liquid based on the information on the second fluid acquired by the fluid information acquisition unit. And a switching device that selectively switches and supplies the fluid ejection head to the fluid ejection head, wherein the fluid information acquisition unit acquires the state of the second fluid, and the fluid information acquisition unit And selectively switching either the second fluid or the functional liquid based on the acquired information on the second fluid and supplying the fluid to the fluid ejecting head.

  According to the present invention, when the state of the second fluid has changed, switching to the functional liquid prevents the second fluid from failing to discharge without causing the state change of the second fluid to proceed further. Can do.

In addition, it is preferable to switch to the functional liquid when the viscosity of the second fluid supplied to the fluid ejecting head exceeds a reference value.
According to the present invention, when the viscosity of the second fluid supplied to the fluid ejecting head becomes equal to or higher than a predetermined value, switching to the functional liquid is performed, thereby preventing discharge failure due to the thickening of the second fluid. Is possible.

In addition, it is preferable to have a time measuring step for measuring the time when the second fluid is supplied to the fluid ejecting head, and to switch to the functional liquid when the time exceeds the reference time.
According to the present invention, it has a time measuring process for measuring the time when the second fluid is supplied to the fluid ejecting head, and when the time exceeds the reference value, the function liquid is switched. Drying of the second fluid from the two nozzles can be prevented.

1 is a schematic diagram illustrating a configuration of an inkjet printer according to a first embodiment. FIG. 3 is a cross-sectional view illustrating a configuration of a recording head. FIG. 3 is a diagram illustrating a configuration of a nozzle surface of a recording head. FIG. 3 is a diagram illustrating a configuration of an ink cartridge. FIG. 3 is a diagram illustrating a configuration of a recording head and its surroundings. FIG. 3 is a block diagram illustrating an electrical configuration of the printer. 6 is a flowchart for explaining recording processing and switching processing in a color printing mode. The block diagram which shows schematic structure of 2nd Embodiment. FIG. 3 is a schematic diagram illustrating a main part configuration around a recording head. The schematic diagram explaining the principle which an induced voltage produces by electrostatic induction. The figure which shows an example of the waveform of the detection signal output from an ink drop sensor.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.

(First embodiment)
FIG. 1 is a partially exploded view showing a schematic configuration of an ink jet printer 1 which is an embodiment of a fluid ejecting apparatus according to the invention.
As shown in FIG. 1, the ink jet printer 1 according to the present embodiment includes a printer body 5 that houses various members. The printer main body 5 stores a head unit moving mechanism 16 that reciprocates the head unit 2 including the recording head 3 (fluid ejecting head) and ink (fluid) that is supplied to the recording head 3 via the supply tube 14. An ink cartridge 6 and a maintenance device 7 used for a cleaning operation for maintaining the ejection characteristics of the recording head 3 are provided.

  The printer body 5 is provided with a transport mechanism (not shown) that transports the recording medium. This transport mechanism transports the recording medium in the Y direction. The recording medium is composed of a conveyance motor and a conveyance roller (not shown) that is rotationally driven by the conveyance motor. The recording medium is sequentially fed onto the platen 13 in conjunction with a recording (printing / printing) operation. Examples of the recording medium include paper, PET, and silver PET.

  The head unit moving mechanism 16 includes a guide shaft 8 installed in the width direction of the printer main body 5, a pulse motor 9, a drive pulley 10 connected to the rotation shaft of the pulse motor 9 and driven to rotate by the pulse motor 9. The driving pulley 10 is an idle pulley 11 provided on the opposite side of the printer body 5 in the width direction, and a timing belt 12 that is stretched between the drive pulley 10 and the idle pulley 11 and connected to the carriage 4. It is comprised.

  The head unit 2 includes a recording head 3 that ejects ink toward the recording medium fed onto the platen 13 and a carriage 4 that can move along the width direction of the recording medium.

  A recording head 3 is mounted on the carriage 4. The carriage 4 is connected to the timing belt 12 by attaching a part of the timing belt 12 to a connecting portion 34 provided at the center of the side portion. The head unit 2 including the carriage 4 reciprocates in the main scanning direction along the guide shaft 8 according to the movement of the timing belt 12 that is rotated by driving the pulse motor 9.

  As shown in FIG. 1, the maintenance device 7 includes a capping mechanism CP (fluid receiving portion) used for suctioning the ink thickened from each nozzle 47 of the recording head 3, and the nozzle surface 3 </ b> A ( The wiping mechanism WP used for the wiping operation for wiping off the ink adhering to FIG. 2) is provided, and is arranged at the home position. Here, the home position is set in an end area within the moving range of the head unit 2 and outside the recording area. When the power is turned off or when recording is not performed for a long time, the head unit 2 is set. Is the place to move.

  When the head unit 2 is located at the home position, the maintenance device 7 performs maintenance processing (ink suction operation, wiping operation, etc.) on the recording head 3. Waste ink discharged from the recording head 3 toward the maintenance device 7 is collected by a waste liquid collecting mechanism (not shown).

FIG. 2 is a cross-sectional view showing a schematic configuration of the recording head 3.
As shown in the figure, the recording head 3 has a head case 18, a flow path unit 19, and an actuator unit 20.

  The head case 18 is a hollow box-shaped member made of synthetic resin, and a case flow path 25 and a housing empty portion 37 are formed inside the head case 18. The case channel 25 is formed so as to penetrate the height direction of the head case 18. The upper end of the case channel 25 is connected to an introduction needle unit (not shown). The lower end of the case flow path 25 communicates with the common ink chamber 44 in the flow path unit 19.

  The actuator unit 20 is housed in the housing space 37. The actuator unit 20 includes a plurality of piezoelectric vibrators 38 arranged in a comb-like shape, a fixed plate 39 to which the piezoelectric vibrators 38 are joined, and wiring for supplying a drive signal from the printer main body side to the piezoelectric vibrators 38. It is comprised from the flexible cable 40 as a member. Each piezoelectric vibrator 38 has a fixed end portion joined to a fixed plate 39 and a free end portion protruding outward from the front end surface of the fixed plate 39, and is attached to the fixed plate 39 in a so-called cantilever state. Yes. The actuator unit 20 is housed and fixed in the housing space 37 by bonding the back surface of the fixing plate 39 to the inner wall surface of the case that defines the housing space 37.

  The flow path unit 19 includes a vibration plate (sealing plate) 41, a flow path substrate 42, and a nozzle plate 43. The vibration plate 41, the flow path substrate 42, and the nozzle plate 43 are stacked in this order, and are joined and integrated with an adhesive (not shown). The vibration plate 41, the flow path substrate 42, and the nozzle plate 43 are members that form a series of ink flow paths from the common ink chamber 44 through the ink supply port 45 and the pressure chamber 46 to the nozzle 47.

  The pressure chamber 46 is formed as an elongated space in a direction orthogonal to the arrangement direction of the nozzles 47. The common ink chamber 44 communicates with the case flow path 25 and is a space into which ink supplied from the ink cartridge 6 via the supply tube 14 is introduced. The ink introduced into the common ink chamber 44 is distributed to each pressure chamber 46 through the ink supply port 45.

  The flow path substrate 42 disposed between the nozzle plate 43 and the vibration plate 41 is a flow path portion that becomes an ink flow path, specifically, a common ink chamber 44, an ink supply port 45, and an empty space that becomes a pressure chamber 46. It is a plate-like member in which a section is formed. The flow path substrate 42 is produced, for example, by subjecting a silicon wafer, which is a crystalline base material, to anisotropic etching.

  The vibration plate 41 is a double-structured composite plate material in which an elastic film is laminated on a metal support plate such as stainless steel. An island portion 48 to which the tip surface of the piezoelectric vibrator 38 is joined is formed in a portion corresponding to the pressure chamber 46 of the vibration plate 41 by removing the support plate in an annular shape by etching or the like. This island part 48 functions as a diaphragm part.

  The vibration plate 41 is configured such that the elastic film around the island portion 48 is elastically deformed in response to the operation of the piezoelectric vibrator 38, seals one opening surface of the flow path substrate 42, and the compliance portion 49. It has come to function as. As for the portion corresponding to the compliance portion 49, the support plate is removed by etching or the like as in the diaphragm portion, and only the elastic film remains.

  The nozzle plate 43 is a plate material made of a metal such as stainless steel, for example, and a plurality of nozzles 47 arranged at a pitch (for example, 180 dpi) corresponding to the dot formation density is formed. Here, as shown in FIG. 3, the nozzle plate 43, that is, the nozzle surface 3A of the recording head 3, is formed with a large number of nozzles 47 as described above, and a plurality of nozzles 47 aligned along the width direction of the recording medium. A nozzle row is constituted by the nozzles 47. A plurality of nozzle rows are provided along the conveyance direction of the recording medium, and in this embodiment, nine nozzle rows L1 to L9 are provided.

FIG. 4 schematically shows the configuration of the ink cartridge 6.
As shown in FIG. 4, the ink cartridge 6 has a color ink cartridge 6A, a white ink cartridge 6B, and a clear ink cartridge 6C.

  The color ink cartridge 6A is a cartridge that individually stores different color inks. In this embodiment, for example, yellow (Y), light yellow (LY), magenta (M), light magenta (LM), cyan (C), and light cyan (LC) are used as eight color inks (first fluid). Black (Bk) and light black (LB) are used. A supply tube 14A is connected to each color ink cartridge 6A.

  The white ink cartridge 6B is a cartridge that stores white ink (second fluid). As a constituent material of the white ink, for example, a pigment system is used. Generally, it is known that the particle size (for example, about 600 nm) of a pigment used as a white ink is larger than the particle size (for example, about 100 nm) of a pigment used as another color ink. A supply tube 14B is connected to the white ink cartridge 6B.

  The clear ink cartridge 6C is a cartridge that contains clear ink (functional liquid) for cleaning. The clear ink is preferably a liquid having a low viscosity and a high fluidity and having a function as a cleaning liquid. Specifically, the solvent etc. which removed the pigment of the ink to be used are mentioned. A supply tube 14C is connected to the clear ink cartridge 6C.

FIG. 5 is a diagram schematically showing the recording head 3 and its peripheral configuration.
As shown in the figure, the supply tube 14 is connected to a nozzle 47 via a flow path 51 in the recording head 3. Among these, the supply tube 14A has one supply tube 14A connected to the nozzle rows L2 to L9 via the flow path 51A, and corresponds to the color ink cartridge 6A (FIG. 4) from the nozzle rows L2 to L9. Color ink is ejected.

  On the other hand, the supply tubes 14B and 14C are connected to the supply tube 14E via the selector 50. The selector 50 has a switching valve (not shown) that selectively connects one of the supply tubes 14B and 14C to the supply tube 14E. This switching valve is operated based on the control of a control device CONT (FIG. 6) described later.

  The supply tube 14E is connected to the nozzle row L1 via the flow path 51B in the recording head 3. Therefore, the nozzle row L1 selectively ejects the white ink stored in the white ink cartridge 6B or the clear ink stored in the clear ink cartridge 6C. The clear ink ejected from the nozzle row L1 is ejected as a cleaning liquid for cleaning the inside of the nozzle 47 in order to prevent clogging of the nozzle 47 provided in the nozzle row L1.

FIG. 6 is a block diagram showing an electrical configuration of the inkjet printer 1.
The ink jet printer 1 in this embodiment includes a control device CONT that controls the overall operation, an input device 59, a storage device 60, a recording medium transport mechanism 35, a maintenance device 7, a recording head 3, a selector 50, a fluid information acquisition unit 70, and A timer unit 73 and the like are provided.

  The control device CONT electrically controls the operation of various components, and includes an input device 59 for inputting various information related to the operation of the ink jet printer 1, a storage device 60 storing various information related to the operation of the ink jet printer 1, A recording medium transport mechanism 35 that transports a recording medium, a maintenance device 7 that performs maintenance processing on the recording head 3, a drive signal generator 62 that generates a drive signal to be input to a drive unit including a piezoelectric vibrator 38, and white ink Various input interface circuits for exchanging data between the fluid information acquisition unit 70 for detecting the state (viscosity, etc.), the selector 50 for switching the supply flow path, the timing unit 73 for measuring the printing time, etc. And a CPU for performing predetermined arithmetic processing based on the above.

  The drive signal generator 62 receives data indicating the amount of change in the voltage value of the ejection pulse input to the piezoelectric vibrator 38 of the recording head 3 and a timing signal that defines the timing for changing the voltage of the ejection pulse. The drive signal generator 62 generates a drive signal such as an ejection pulse based on the input data and timing signal.

  The fluid information acquisition unit 70 has a temperature sensor 71. The temperature sensor 71 is a thermistor attached to the nozzle plate 43 of the recording head 3, detects the temperature of the nozzle plate 43 as the ink temperature, and outputs the temperature information to the control device CONT.

  The timer 73 measures the time during which the state where the white ink is supplied to the recording head 3, that is, the time during which the white ink is left unused in the color printing mode, and outputs the time to the control device CONT. .

When the temperature of the ink obtained from the fluid information acquisition unit 70 exceeds a preset reference value, the control device CONT switches the supply tube to replace the white ink in the recording head 3 with the clear ink. The selector 50 is instructed. Further, the control device CONT has a timer unit when the count time from the timer unit 73 exceeds a preset reference time even if the temperature detected by the fluid information acquisition unit 70 is within the reference value. The information from 73 is given priority to the selector 50.
The selector 50 selectively connects one of the supply tubes 14B and 14C to the recording head 3 based on a command from the control device CONT.

Next, the operation of the printer 1 configured as described above will be described. FIG. 7 is a flowchart for explaining recording processing and switching processing in the color printing mode.
When the inkjet printer 1 performs a recording operation based on print data from the outside, the control device CONT develops the print data into ejection data corresponding to the dot pattern, and supplies a drive signal of the developed ejection data to the recording head 3. To do. In the recording operation, when white data is not included in the print data, the recording operation is performed using the nozzle rows L2 to L9 of the recording head 3 (color printing mode). In addition, when white data is included in print data regardless of the presence or absence of color data, a recording operation is performed using the nozzle row L1 (white print mode).

  In the white printing mode, the nozzle row L1 of the recording head 3 is used during recording regardless of the presence or absence of color data. Therefore, the selector 50 is checked before the white ink is ejected, and the supply tube 14B and the supply tube are checked. When 14E is not connected, the selector 50 is controlled so that these are connected.

  The control device CONT supplies a drive signal of ejection data to the piezoelectric vibrator 38 corresponding to the nozzle row L1 used for the recording operation. Due to the drive signal, the piezoelectric vibrator 38 expands and contracts in the longitudinal direction of the element, and accordingly, the island portion 48 moves in a direction toward or away from the pressure chamber 46.

  The volume of the pressure chamber 46 is changed by the movement of the island portion 48, and a pressure fluctuation occurs in the ink in the pressure chamber 46. The ink fluctuation D of the white ink is ejected from each nozzle 47 of the nozzle row L1 by this pressure fluctuation. The control device CONT records an image, characters, or the like on a recording sheet or the like by ejecting ink droplets D while scanning the recording head 3.

  As described above, it is known that the particle size (for example, about 600 nm) of the pigment used as the white ink is larger than the particle size (for example, about 100 nm) of the pigment used as the other color ink. A large particle size causes sedimentation (sedimentation rate is proportional to the square of the particle diameter: Stokes' theorem), and the pigment is thickened as a result of sedimentation. For this reason, when the non-ejection state continues, there is a possibility that ejection failure may occur due to thickening of the white ink.

  For this reason, when there is a time interval from the recording operation including white data until the next recording process is started, the timer 73 starts counting the non-use time of the white ink. Then, the non-use time (non-ejection time) of the white ink by the time measuring unit 73 is confirmed, and when it is confirmed that the non-use time exceeds a preset reference time, the control device CONT counts by the time measuring unit 73. And the selector tube 50 is controlled to switch the supply tube so that the supply tube 14C and the supply tube 14E are connected. As a result, the clear ink cartridge 6C is connected to the nozzle row L1 of the recording head 3, and the clear ink is supplied into the recording head 3 instead of the white ink. The replacement of the clear ink and the white ink is performed on the capping mechanism CP, and the white ink discharged from the recording head 3 is collected by the capping mechanism CP.

Then, when shifting to the color printing mode with the clear ink filled, recording processing with the color ink is executed in this state. In the color printing mode, since the print data does not include white, printing is performed using the nozzle rows L2 to L9 excluding the nozzle row L1 of the recording head 3. For this reason, it is possible to prevent a change in the state of the white ink by executing color printing in a state where the clear ink is filled.
When the white printing mode is executed again, the recording process is resumed after the clear ink in the recording head 3 is replaced with the white ink.

On the other hand, when the color printing mode is started after the white printing mode is finished and before the reference time is exceeded, the supply tube 14B and the supply tube 14E are connected, and the recording head 3 has a white color. Ink is filled.
As shown in FIG. 7, the control device CONT counts the non-use time of the white ink described above by the time measuring unit 73 (step S1). After the start of color printing (step S2), the temperature of the ink in the recording head 3 is detected in real time by the temperature sensor 71 to monitor the white ink state (thickened state) (step S3). As described later, it is determined whether or not it is necessary to switch to clear ink (step S4). In this embodiment, the temperature and non-use time of the white ink are used as determination parameters for determining whether or not to switch ink.

  In this embodiment, the temperature of the recording head 3 is measured by the temperature sensor 71 and the viscosity of the white ink is estimated from this temperature. Actually, the temperature of the nozzle plate 43 is measured, and this measured temperature is regarded as the temperature of the white ink. The upper limit of the image quality guarantee temperature of white ink is about 35 ° C., and this image quality guarantee temperature is set as a reference temperature (reference value). The image quality guarantee temperature is appropriately set according to the particle size and number of pigment particles, and is set within a range of 35 ° C. to 40 ° C., for example.

  Then, the control device CONT determines that it is not necessary to replace the ink when the temperature is lower than the image quality guarantee temperature or the non-use time is within the reference time (step S4), and the color printing is continued (step S5). Then, the thickened state of the white ink is monitored until it is determined that color printing is finished (steps S6 and S3).

  Further, the control device CONT needs to replace the ink when the ink temperature (detected value by the temperature sensor 71) rises to the reference temperature or higher during the recording process and the viscosity of the white ink exceeds the reference value. If it is determined (step S4), the counting by the time measuring unit 73 is ended (step S7), the recording head 3 is moved to the home position, and then the ink supplied to the recording head 3 is used from the white ink that is not used for printing. Switching to clear ink (step S8). Then, the color printing is resumed with the clear ink filled, and the printing is continued until the color printing is finished (step S9).

  Further, when the count of the non-use time (color printing time) of the white ink by the time measuring unit 73 exceeds the reference time during the recording process, the control device CONT has detected the temperature detected by the temperature sensor 71 at the reference value. Even if not, priority is given to the information from the timer 73, and it is determined that the supply ink needs to be switched (step S4). Then, the color printing is interrupted, the white ink in the recording head 3 is replaced with the clear ink, and then the color printing is resumed. In this way, printing is continued until color printing is finished, and the recording process is finished (step S10).

  When the recording process ends, the control device CONT determines whether or not cleaning is necessary. When it is determined that cleaning is necessary, a flushing process is executed as a cleaning process. In the flushing process, wasteful consumption of white ink is suppressed by ejecting clear ink.

  As described above, according to the present embodiment, during the color printing mode, the non-ejecting state of the white ink is monitored by detecting the non-use time of the white ink and the environmental temperature (ink temperature in the present embodiment). When a factor that increases the viscosity of the non-jetting white ink even a little is confirmed during the execution, the white ink in the recording head 3 is replaced with a clear ink that is less likely to thicken and settle than the white ink. . As a result, it is possible to prevent the white ink that tends to thicken compared to other color inks from thickening when not in use, and to prevent discharge failure of the white ink when shifting to the white print mode. it can.

  Until now, the white ink flushing process was regularly executed during the color printing mode to prevent the white ink from thickening, but there was a problem that a large amount of white ink was consumed during the flushing process. there were.

  In contrast, in this embodiment, as described above, when the image quality guarantee temperature or the non-use time of the white ink exceeds the reference time, the white ink in the recording head 3 is discharged and replaced with the clear ink. By ejecting clear ink, a large amount of white ink is not consumed. As a result, wasteful consumption of the white ink can be prevented and the cost for the white ink can be reduced.

  In this embodiment, since the reference time is prioritized over the reference temperature as the timing for replacing the white ink with the clear ink, the clear ink is always changed to the clear ink when the white ink is not ejected and a predetermined time elapses. Thus, even when used in a low temperature environment, defective ejection of white ink can be reliably prevented.

(Second Embodiment)
Next, an ink jet printer according to a second embodiment will be described. FIG. 8 is a block diagram illustrating a schematic configuration of the second embodiment, and FIG. 9 is a schematic diagram illustrating a configuration of a main part around the recording head. The ink jet printer of this embodiment is the same as that of the previous embodiment, but differs in that an ink droplet sensor 80 is provided instead of the temperature sensor. Therefore, in the following description, the ink droplet sensor 80 will be described in detail.

  The ink jet printer 90 of this embodiment includes an ink droplet sensor 80 (fluid information acquisition unit) that can detect the ink droplet D ejected from the recording head 3 (see FIGS. 8 and 9). The ink droplet sensor 80 charges the ink droplet D ejected from the nozzle of the recording head 3, and outputs a voltage change based on electrostatic induction when the charged ink droplet D flies as a detection signal. It is configured to make it possible to grasp the ink discharge state of the nozzles.

  The ink droplet sensor 80 shown in FIGS. 8 and 9 is arranged to face the nozzle surface 3A of the recording head 3 with a predetermined gap, and has a detection unit 78 to which ink ejected from the nozzle 47 is supplied. The detection device 76 that can detect the ink discharge state at each nozzle 47 by outputting a detection waveform corresponding to the ink discharged from the nozzle 47, and the ink based on the detection waveform output from the detection device 76 And a processing device 82 for acquiring information related to the weight of the machine.

  The detection device 76 includes a voltage applicator 75 that applies a voltage between the detection unit 78 and the nozzle surface 3 </ b> A of the recording head 3, and a voltage detector 81 that detects the voltage of the detection unit 78. In the present embodiment, the detection unit 78 of the detection device 76 is provided inside the cap member 15 constituting the capping mechanism CP arranged at the home position as described above.

  The cap member 15 is a tray-like member having an open upper surface, and is made of an elastic member such as an elastomer. An ink absorber 77 and an electrode member 79 are disposed inside the cap member 15. The electrode member 79 is formed of a metal mesh member such as stainless steel. The detection unit 78 is formed by the upper surface of the electrode member 79. The detection unit 78 is disposed at a position lower than the upper end surface of the cap member 15. The ink absorber 77 is formed of a sponge-like member capable of holding (absorbing) the ink L, a porous member, or the like.

  The ink droplet D that has landed on the detection unit 78 passes through the gap between the grid-like electrode members 79 and is held (absorbed) by the ink absorber 77 disposed on the lower side. Note that the electrode member 79 may not be a mesh member as long as the ink droplet D can pass therethrough. Further, a tube (not shown) is connected to the bottom of the cap member 15, and the ink droplet D of the ink absorber 77 is sucked by the suction pump 17 through the tube and discharged to the outside. .

  The voltage applicator 75 includes an electronic circuit that can apply a voltage between the ejection surface (nozzle surface 3 </ b> A) of the nozzle plate 43 of the recording head 3 and the detection unit (upper surface) 78 of the electrode member 79. In the present embodiment, the voltage applicator 75 electrically connects the electrode member 79 and the nozzle plate 43 via a DC power source and a resistance element so that the electrode member 79 is a positive electrode and the nozzle plate 43 is a negative electrode. Connecting.

  As described above, the nozzle plate 43 is formed of a plate material such as stainless steel, the electrode member 79 is formed of a metal such as stainless steel, and each of the nozzle plate 43 and the electrode member 79 has conductivity. That is, the voltage applicator 75 can apply a voltage between the nozzle surface 3 </ b> A and the detection unit 78.

  The voltage detector 81 integrates and outputs the voltage signal of the electrode member 79, an inverting amplifier circuit that inverts and amplifies the signal output from the integration circuit, and a signal output from the inverting amplifier circuit. A / D conversion circuit for A / D converting and outputting.

  In the present embodiment, the detection device 76 applies an electric field between the nozzle surface 3 </ b> A and the detection unit 78 to temporally generate a voltage value based on electrostatic induction when ink moves from the nozzle 47 to the detection unit 78. The change is output to the processing device 82 as a detected waveform. The processing device 82 can perform arithmetic processing on the output of the detection device 76, and can acquire information on the weight of the ink based on the detection waveform output from the detection device 76. Then, the acquired information is output to the control device CONT. The control device CONT controls the selector 50 based on information from the processing device 82 (ink droplet sensor 80).

  Next, the principle of the ink droplet sensor 80, that is, the principle that an induced voltage is generated by electrostatic induction will be described with reference to the drawings. FIG. 10 is a schematic diagram for explaining the principle in which an induced voltage is generated by electrostatic induction. FIG. 10A shows a state immediately after the ink droplet D is ejected, and FIG. The state which landed on the test | inspection area | region 74 of the cap member 15 is shown. FIG. 11 is a diagram illustrating an example of a waveform of a detection signal (for one drop of ink) output from the ink drop sensor 80.

  In a state where a voltage is applied between the nozzle plate 43 and the electrode member 79, the piezoelectric vibrator 38 is driven using the ejection pulse DP, and the ink droplet D is ejected from any one nozzle 47. At this time, since the nozzle plate 43 is a negative electrode, as shown in FIG. 10A, a part of the negative charge of the nozzle plate 43 moves to the ink droplet D, and the discharged ink droplet D becomes negative. Charge. Then, as the ink droplet D approaches the detection unit 78 of the cap member 15, positive charges increase on the surface of the electrode member 79 due to electrostatic induction. Thereby, the voltage between the nozzle plate 43 and the electrode member 79 becomes higher than the initial voltage value in the state where the ink droplet D is not ejected due to the induced voltage generated by electrostatic induction.

  Thereafter, as shown in FIG. 10B, when the ink droplet D lands on the electrode member 79, the negative charge of the ink droplet D neutralizes the positive charge of the electrode member 79. For this reason, the voltage between the nozzle plate 43 and the electrode member 79 is lower than the initial voltage value. Thereafter, the voltage between the nozzle plate 43 and the electrode member 79 returns to the initial voltage value.

  Therefore, as shown in FIG. 11, the detection waveform output from the ink droplet sensor 80 is a waveform that once rises, then falls to below the initial voltage value, and then returns to the original voltage value. In this way, the ink droplet sensor 80 detects a voltage change when the ink droplet D is ejected from each nozzle 47.

  However, when the ink droplet D is thickened, for example, even when the same ejection pulse DP is used, the ejection amount (liquid amount) decreases compared to the normal time. Therefore, as shown by the solid line in FIG. 11, the amplitude A of the detection signal (detection waveform Z) output from the ink droplet sensor 80 is the amplitude of the detection signal at the normal time (ideal waveform Z0: broken line in FIG. 11). It becomes smaller than A0 (amplitude difference ΔA). In addition, the time from when the ejection pulse DP is applied until the ink droplet D is separated from the nozzle plate 43 is also slower than in the normal state (the timing at which the voltage rises is shifted by the time difference ΔT).

  Therefore, by comparing the amplitude A of the detection waveform Z output from the ink droplet sensor 80 and the timing of voltage rise with those of the ideal waveform Z0 (detection of ΔA and ΔT), ink in each nozzle 47 of the recording head 3 is detected. A thickened state of L can be obtained. Further, in a state where the ink is thickened, the ink cannot be ejected from the nozzle 47 favorably, resulting in a defective nozzle. In this state, no ink is ejected, so no waveform is detected. That is, as described above, the ink droplet sensor 80 can detect the ink ejection status (determining whether or not the nozzle is defective) at each nozzle 47.

In the present embodiment, the ink droplet sensor 80 periodically detects the thickened state of the white ink in the color printing mode, and when the thickening of the white ink is detected, the white ink in the recording head 3 is replaced with the clear ink. .
In this embodiment as well, when the non-use time of the white ink exceeds a preset reference time, control may be performed so that the white ink is replaced with the clear ink. However, since the ink drop sensor 80 can be used to reliably grasp the state of the white ink, the selector 50 is controlled based on the detection result of the ink drop sensor 80, so that the conditions such as the use environment can be considered. Therefore, it is possible to reliably prevent the discharge failure of the white ink.

  As described above, the preferred embodiments according to the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to the examples. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

  For example, a humidity sensor may be adopted instead of the temperature sensor used in the previous embodiment. By detecting the environmental humidity using a humidity sensor, the ink thickening state may be monitored from the dry state of the opening of the nozzle 47.

  In the above embodiment, the capping mechanism CP is used as a receiving portion for receiving ink during the flushing operation. However, the present invention is not limited to this. For example, a configuration in which a separate flushing receiving portion is provided. I do not care.

  In the above embodiment, an ink jet printer and an ink cartridge are employed. However, a fluid ejecting apparatus that ejects or ejects fluid other than ink and a fluid container that contains the fluid are employed. Also good. The present invention can be applied to various fluid ejecting apparatuses including a fluid ejecting head that ejects a minute amount of liquid droplets. In addition, a droplet means the state of the fluid discharged from the said fluid ejecting apparatus, and includes what pulls a tail in granular shape, tear shape, and thread shape. Moreover, the fluid here may be a material that can be ejected by the fluid ejecting apparatus.

  For example, it may be in the state when the substance is in a liquid phase, and may be in a liquid state with high or low viscosity, sol, gel water, other inorganic solvents, organic solvents, solutions, liquid resins, liquid metals (metal melts) ) And a fluid as one state of the substance, as well as particles in which functional material particles made of solid substances such as pigments and metal particles are dissolved, dispersed or mixed in a solvent. In addition, typical examples of the fluid include ink and liquid crystal as described in the embodiment. Here, the ink includes general water-based inks and oil-based inks, and various fluid compositions such as gel inks and hot-melt inks.

  As a specific example of the fluid ejecting apparatus, for example, a fluid containing a material such as an electrode material or a color material used for manufacturing a liquid crystal display, an EL (electroluminescence) display, a surface emitting display, or a color filter in a dispersed or dissolved form. It may be a fluid ejecting apparatus for ejecting, a fluid ejecting apparatus for ejecting a bio-organic matter used for biochip manufacturing, a fluid ejecting apparatus for ejecting a fluid used as a precision pipette, a printing apparatus, a microdispenser, or the like.

  In addition, transparent resin liquids such as UV curable resins to form fluid injection devices that inject lubricating oil onto precision machines such as watches and cameras, micro hemispherical lenses (optical lenses) used in optical communication elements, etc. Alternatively, a fluid ejecting apparatus that ejects a liquid onto the substrate or a fluid ejecting apparatus that ejects an etching solution such as acid or alkali to etch the substrate may be employed. The present invention can be applied to any one of these ejecting apparatuses and fluid containers.

DESCRIPTION OF SYMBOLS 1,90 ... Recording head (fluid ejecting head), 3 ... Recording head (fluid ejecting head), 15 ... Cap member (fluid receiving part), 43 ... Nozzle plate, 47 ... Nozzle, 50 ... Selector (switching device), 70 ... fluid information acquisition unit, 71 ... temperature sensor, 73 ... timing unit, 80 ... ink drop sensor (fluid information acquisition unit), 6C ... clear ink cartridge (storage unit), L1 ... nozzle row (second nozzle row), L2 -L9 ... Nozzle row (first nozzle row)

Claims (8)

A fluid ejecting head having a plurality of first nozzle rows for ejecting a first fluid and a second nozzle row for ejecting a second fluid or a functional liquid;
A fluid information acquisition unit for acquiring a state of the second fluid;
A switching device that selectively switches one of the second fluid and the functional liquid and supplies the fluid to the fluid ejecting head based on the information on the second fluid acquired by the fluid information acquisition unit; A fluid ejecting apparatus comprising: The fluid information acquisition unit has a temperature sensor for measuring the temperature of the second fluid;
The fluid according to claim 1, wherein the switching device selectively switches between the second fluid and the functional liquid based on the temperature of the second fluid acquired by the temperature sensor. Injection device. The fluid information acquisition unit forms an electric field between a nozzle plate on which the first nozzle row and the second nozzle row are formed and a fluid receiving unit that is disposed in a non-contact state with respect to the nozzle plate. Possible configuration,
The switching device selectively switches between the second fluid and the functional liquid based on a discharge amount of the second fluid acquired by the fluid information acquisition unit. The fluid ejecting apparatus according to the description.   4. The fluid ejecting apparatus according to claim 1, further comprising a time measuring unit that measures a time during which the second fluid is supplied to the fluid ejecting head. 5. A fluid ejecting head having a plurality of first nozzle rows for ejecting a first fluid and a second nozzle row for ejecting a second fluid or a functional liquid;
A reservoir for storing the second fluid and the functional liquid;
A switching device that is disposed between the fluid ejecting head and the reservoir, and selectively supplies either the second fluid or the functional liquid to the fluid ejecting head.
The switching device selectively switches either the second fluid or the functional liquid to supply to the fluid ejecting head according to a thickened state of the second fluid. apparatus. A fluid ejection head having a plurality of first nozzle rows for ejecting the first fluid and a second nozzle row for ejecting the second fluid or functional liquid, and fluid information acquisition for acquiring the state of the second fluid And a switching device that selectively switches one of the second fluid and the functional liquid to supply to the fluid ejecting head based on information on the second fluid acquired by the fluid information acquisition unit And a maintenance method for a fluid ejection device comprising:
Acquiring the state of the second fluid by the fluid information acquisition unit;
And selectively switching either the second fluid or the functional liquid to the fluid ejecting head based on the information on the second fluid acquired by the fluid information acquisition unit. An operation method of a fluid ejecting apparatus.   The method of operating a fluid ejecting apparatus according to claim 6, wherein when the viscosity of the second fluid supplied to the fluid ejecting head exceeds a reference value, the fluid is switched to the functional liquid. A time measuring step for measuring a time when the second fluid is supplied to the fluid ejecting head;
The operation method of the fluid ejecting apparatus according to claim 6, wherein when the measured time exceeds a reference time, the function liquid is switched.

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