JP6769198B2 - Liquid discharge device, liquid supply device, liquid supply method - Google Patents

Description

The present invention relates to a device for discharging a liquid, a liquid supply device, and a liquid supply method.

Some use a flow-through type liquid discharge head having a liquid supply port and a liquid discharge port, and supply the liquid to the liquid discharge head while circulating the liquid through the liquid discharge head when the liquid is being discharged. ..

Conventionally, a supply path provided so as to connect a first storage unit for storing ink supplied to the recording head and the recording head and the first storage unit and through which ink supplied from the first storage unit to the recording head passes. And the connection between the first storage unit and the pressure control unit, which is connected to the first storage unit and makes the pressure of the nozzle of the recording head in a negative pressure state via the first storage unit and the supply path. A first switching unit that switches between opening and closing, a second storage unit that stores ink supplied to the first storage unit, and a supply unit that supplies ink stored in the second storage unit to the first storage unit. A collection path provided to connect the head and the second storage section, through which a part of the ink supplied to the recording head passes and is returned to the second storage section, and a second switching section for switching the opening and closing of the recovery path. A control unit that controls the operation of the first switching unit, the second switching unit, and the supply unit is provided, and the control unit closes the connection between the first storage unit and the pressure control unit by the first switching unit. In addition, with the collection path closed by the second switching unit, the supply unit is operated so as to supply the ink stored in the second storage unit to the first storage unit, thereby ejecting ink from a plurality of nozzles of the recording head. There is a device that controls the operation (Patent Document 1).

WO2013 / 137057

By the way, when the liquid is discharged from the liquid discharge head, if the liquid feeding means that circulates the liquid in the circulation path is accelerated or decelerated, the liquid is discharged from the liquid discharge head due to the pressure fluctuation in the circulation path. There is a problem of instability.

The present invention has been made in view of the above problems, and an object of the present invention is to ensure discharge stability.

In order to solve the above problems, the device for discharging the liquid according to the present invention is
A circulation path in which the liquid circulates through a liquid discharge head that discharges the liquid to the printed medium to be conveyed .
At least one of a liquid feeding means for sending the liquid in the circulation path and a liquid feeding means for sending the liquid to the circulation path.
The liquid feeding control means for controlling the liquid feeding operation of the liquid feeding means is provided.
The liquid feed control means
The operation of changing the liquid feeding amount of the liquid feeding means is at least when the liquid is not discharged from the liquid discharging head and when the liquid is discharged from the liquid discharging head for the purpose of maintaining and recovering the liquid discharging head. the control carried out either,
The time for changing the liquid feed amount of the liquid feed means is changed according to the transport speed of the print medium .

According to the present invention, discharge stability can be ensured.

It is a side explanatory view which shows an example of the apparatus which discharges a liquid which concerns on this invention. It is explanatory drawing of the main part of the liquid discharge unit. It is a plane explanatory view of an example of the liquid discharge head of the liquid discharge unit. It is a block explanatory drawing of the part which concerns on the liquid supply device in this device. It is a block explanatory drawing of the outline of the control means of the apparatus which discharges the liquid. It is a block explanatory diagram of the higher-level device which constitutes the control means. It is a block explanatory diagram of the output control device which comprises the control means. It is explanatory drawing which provides the explanation of the pressure fluctuation in a liquid supply device (circulation system). It is explanatory drawing of the region on the continuum which provides the explanation of 1st Embodiment of this invention. Similarly, it is explanatory drawing of the positional relationship between the region on the continuum, and the head unit which is used for the explanation of the operation which changes the liquid feed amount of a liquid feed pump. Similarly, it is explanatory drawing of the positional relationship between a print medium and a head unit which provides the operation which changes the liquid feed amount of a liquid feed pump when a discontinuous print medium is used. It is explanatory drawing of an example of a decompression sub-tank. It is explanatory drawing of an example of the liquid level sensor of the decompression sub-tank. It is explanatory drawing of the decompression tank which provides the detection information (sensor information) of a liquid level sensor. It is explanatory drawing of the sensor information. It is explanatory drawing of an example of a pressurized sub-tank. It is explanatory drawing of the pressurizing tank which provides the explanation of the detection information (sensor information) of a liquid level sensor. It is explanatory drawing of the sensor information. It is a bath diagram provided for the explanation of the drive control of the 1st liquid feed pump in the 1st Embodiment. It is a bath diagram provided for the explanation of the drive control of the 2nd liquid feed pump in the 1st Embodiment. It is a flow figure which provides the setting of the acceleration / deceleration of the liquid feed pump in the 2nd Embodiment of this invention. Similarly, it is explanatory drawing which provides the explanation of the relationship between the acceleration / deceleration time and a non-printing area. It is a block explanatory drawing of another example of the liquid supply device which concerns on this invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. First, an example of a device for discharging a liquid according to the present invention will be described with reference to FIG. FIG. 1 is a schematic explanatory view of the device.

The printing device 100, which is a device for discharging the liquid, preprocesses the carry-in means 1 for carrying in the continuum 10 as a printing medium, which is an imparting member to which the liquid such as roll paper is applied, and the carried-in continuum 10. It includes a pretreatment means 2 for applying the liquid and a drying means 3 for drying the continuum 10 to which the pretreatment liquid is applied.

Further, the device 100 is printed by the guide transport means 4 that guides and conveys the continuum 10 that has passed through the drying means 3 to the printing means 5, and the printing means 5 that discharges liquid to the continuum 10 to print. The continuous body 10 is provided with a post-treatment means 6 for performing post-treatment, a drying means 7 for drying the continuous body 10, a discharging means 9 for discharging the continuous body 10, and the like.

Here, the carry-in means 1 is composed of a main winding roller 11, a plurality of transport rollers 12, and the like. The carry-in means 1 uses a transport roller 12 or the like to carry (move) the continuous body 10 wound and held around the original winding roller 11 and transports it to the pretreatment means 2 or the like.

The pretreatment means 2 uniformly applies the pretreatment liquid having a function of aggregating the liquid given by the printing means 5 to the surface of the continuum 10.

As pretreatment methods, for example, blade coating method, gravure coating method, gravure offset coating method, bar coating method, roll coating method, knife coating method, air knife coating method, comma coating method, U comma coating method, AKKU coating method, smoothing coating. A method, a microgravure coating method, a reverse roll coating method, a 4- to 5-roll coating method, a dip coating method, a curtain coating method, a slide coating method, a die coating method and the like can be used.

Further, as the pretreatment liquid, for example, a treatment liquid containing a water-soluble aliphatic organic acid can be used. Here, the treatment liquid containing a water-soluble aliphatic organic acid is a treatment liquid having a property of aggregating a water-dispersible colorant. Further, agglomeration means that the water-dispersible colorant particles are adsorbed and aggregated with each other.

Further, the pretreatment means 2 can adsorb ions on the surface of the water-dispersible colorant by adding an ionic substance such as a water-soluble aliphatic organic acid to the pretreatment liquid. As a result, the pretreatment means 2 can neutralize the surface charge of the water-dispersible colorant. In addition, the pretreatment means 2 can enhance the aggregating action due to the intermolecular force and further agglomerate the water-dispersible colorant.

The printing means 5 discharges the liquid to the continuum 10 transported on the transport guide member 59. For example, full-line head units 51K, 51C, 51M, 51Y for four colors (hereinafter, referred to as "head unit 51" when colors are not distinguished) are arranged in the printing means 5 from the upstream side in the medium transport direction. Has been done.

Each head unit 51 is a liquid discharging means, and discharges black K, cyan C, magenta M, and yellow Y liquids to the conveyed continuum 10. The types and numbers of colors are not limited to this.

As shown in FIG. 2, for example, the head unit 51 uses a plurality of liquid discharge heads (hereinafter, referred to as “heads”) 101 arranged in a staggered pattern on the base member 52 to form a head array. , Not limited to this. As shown in FIG. 3, the head 101 has a plurality of nozzles 102 for discharging a liquid.

Next, a portion of the device related to the liquid supply device will be described with reference to FIG. FIG. 4 is a block explanatory view of the liquid supply device.

The liquid supply device 200 includes a main tank 201, a second liquid feeding pump 202 as a second liquid feeding means, a depressurizing sub tank (circulation tank) 210, a first liquid feeding pump 221 as a first liquid feeding means, and a pressurized sub tank ( A supply tank) 230, a pressurized head tank 251 and a decompressed head tank 252 are provided.

In the decompression sub-tank 210, liquid is sent from the main tank 201, which is a liquid storage means for storing the liquid discharged from the head 101, by the second liquid feeding pump 202. The second liquid feed pump 202 is driven based on the detection result of the liquid level detecting means 211 that detects the liquid level of the decompression sub-tank 210.

A pressure adjusting mechanism 214 and a vacuum pump 213, which is a gas pump, are connected to the decompression sub-tank 210 to reduce the pressure to a predetermined pressure. The vacuum pump 213 is the pressure detection information of the pressure gauge 212 that detects the pressure of the gas inside the decompression sub tank 210, or the pressure gauge 242 that detects the pressure of the liquid arranged between the decompression sub tank 210 and the decompression head tank 252. It is driven based on the pressure detection information of.

The decompression sub-tank 210 is connected to the pressurization sub-tank 230 via the first liquid feed pump 221. A degassing module 222 is interposed between the first liquid feeding pump 221 and the pressurizing sub tank 230, and a vacuum pump 223 is connected to the degassing module 222.

A pressure adjusting mechanism 234 and a compressor 233, which is a gas pump, are connected to the pressurizing sub tank 230 to pressurize the pressure to a predetermined pressure. The compressor 233 is the pressure detection information of the pressure gauge 212 that detects the pressure of the gas inside the pressurizing sub tank 230, or the pressure that detects the pressure of the liquid arranged between the pressurizing sub tank 230 and the pressurizing head tank 251. It is driven based on a total of 242 pressure detection information.

The first liquid feed pump 221 is driven when the liquid level falls below a predetermined height based on the detection result of the liquid level sensor 231 that detects the liquid level in the pressurized sub tank 230.

As pumps such as the first liquid feed pump 221 and the second liquid feed pump 202, the vacuum pump 213, and the compressor 233, a diaphragm pump, a tube pump, a piston pump, a gear pump, and the like are used.

In the liquid supply device 200, the circulation path 250 is composed of the pressurized sub tank 230, the pressurized head tank 251 and the head 101, the decompressed head tank 252, and the decompressed sub tank 210. The first liquid feed pump 221 feeds the liquid in the circulation path 250, and the second liquid feed pump 202 sends the liquid to the circulation path 250.

A pressure difference is given between the decompression sub-tank 210 and the pressurization sub-tank 230, and the pressure difference causes the pressurization sub-tank 230 to pass through the pressurization head tank 251, the head 101, and the decompression head tank 252 to reduce the pressure. Liquid flows to the sub tank 210.

Here, when the liquid is not consumed by the head 101 for discharge or the like, when the liquid flows from the pressurized sub tank 230 to the decompressed sub tank 210 due to the pressure difference, the liquid level of the pressurized sub tank 230 drops. The liquid level sensor 231 detects a drop in the liquid level, and the first liquid feeding pump 221 operates to feed the liquid to the pressurized sub tank 230 to replenish the liquid.

In this way, the liquid is circulated within the circulation path 250.

Further, when the liquid is consumed by the head 101 for discharge or the like, in addition to the circulation when the liquid is not consumed by the discharge or the like at the head 101, the liquid level of the decompression sub-tank 210 is increased by the amount consumed by the head 101. descend. The liquid level sensor 211 detects a drop in the liquid level, and the second liquid feeding pump 202 operates to supply the liquid from the main tank 201 to the decompression sub tank 210 to replenish the liquid.

In this way, the liquid consumed by the head 101 is replenished.

By circulating the liquid in the head 101 in this way, it is possible to constantly collect the liquid in the vicinity of the nozzle 102 of the head 101 and continue to supply the fresh liquid. As a result, the solvent dries and evaporates in the vicinity of the nozzle 102 to increase the viscosity, and it is possible to suppress or prevent the occurrence of ejection abnormality.

Further, when bubbles are generated in the head 101 due to a pressure change or a temperature change in the head 101, the bubbles can be expelled to the outside of the head 101, and discharge abnormality due to the bubbles can be prevented, suppressed, and self-healed.

Next, an outline of the control means of this device will be described with reference to FIGS. 5 to 7. FIG. 5 is a block explanatory view of the control means, FIG. 6 is a block explanatory view of a higher-level device constituting the control means, and FIG. 7 is a block explanatory view of an output control device constituting the control means. Note that FIG. 7 mainly shows a part related to liquid supply control.

The control unit 700 receives print job data from the host side, processes it, and transfers it to the output control device 500, and an output control device that receives print image data from the host device 600 and controls printing. It is composed of 500.

The host device 600 performs RIP (Raster Image Processor) processing that requires processing time. The output control device 500 performs a printing process.

The host device 600 is a device that performs RIP (Raster Image Processor) processing based on print job data (job data, print data) output from the host device. That is, the host device 600 creates print image data which is bitmap data corresponding to each color based on the print job data.

Further, the host device 600 creates control information data which is data for controlling the printing operation based on the print job data, the information of the host device, and the like. Here, the control information data includes printing conditions (printing form, printing type, paper supply / output information, printing surface order, printing paper size, print image data data size, resolution, paper type information, gradation, color information, and the like. Includes data about (such as information on the number of pages to print).

Here, as shown in FIG. 6, the host device 600 includes a CPU 601 and a ROM 602, a RAM 603, an HDD 604, an external I / F 605, an image data I / F 606, a control information I / F 607, and the like.

Then, the print job data is received from the host device via the external I / F 605, the bitmap data of YMCK is generated, the generated bitmap data of each color is written to the RAM 603, and the bitmap data of each color is compressed. It is encoded and temporarily stored in HDD 604.

After that, when the printing operation is started, the bitmap data of each color is decoded and temporarily written to the RAM 603, the bitmap data of each color is read out, and the print image data of each color is used as the print image data of each color via the image data I / F606. Then, the data is transferred to the output control device 500 side.

Further, the control information data is transmitted and received to and from the output control device 500 via the control information I / F 607 according to the progress of the printing operation.

As shown in FIG. 7, the output control device 500 includes a main control unit (a main control unit) including a microcomputer including a CPU 511, a ROM 512, a RAM 513, an I / O, etc., which controls the entire device, an image memory, a communication interface, and the like. The system controller) 501 is provided.

The main control unit 501 sends the print image data to the print control unit 502 in order to print the image on the continuum 10 based on the print image data and the print information data transferred from the host device 600.

The print control unit 502 transfers the print image data received from the main control unit 501 as serial data, and heads the transfer clock, latch signal, control signal, etc. necessary for transferring the print data and confirming the transfer. Output to driver 503.

Further, the print control unit 502 includes a drive waveform generation unit including a D / A converter that D / A-converts pattern data of a common drive waveform stored in an internal ROM, a voltage amplifier, a current amplifier, and the like. A drive waveform composed of one drive pulse or a plurality of drive pulses is output to the head driver 503.

The head driver 503 selects a drive pulse constituting a drive waveform given from the print control unit 502 based on print image data corresponding to one head unit 51 input serially, and gives the liquid to the pressure generating means. Discharge. At this time, by selecting a part or all of the pulses constituting the drive waveform or all or a part of the waveform elements forming the pulse, dots having different sizes such as large droplets, medium droplets, and small droplets can be formed. Can be beaten.

Further, the main control unit 501 provides the transfer control unit 504 with information (information such as transfer start, transfer stop, transfer speed, etc.) necessary for the transfer of the continuous body 10. The transport control unit 504 includes the original winding roller 11 of the carry-in means 1, the carry-in means 1, the drying means 3, the guide transport means 4, the drying means 7 and the discharge means 9, and the take-up roller 91 of the discharge means 9. Drive and control the rollers 510. It is not necessary to apply the driving force to all the rollers.

Further, the main control unit 501 gives information regarding the print start, print end, print area, non-print area, and the like to the liquid supply control unit 506 that also serves as the liquid feed control means. The print area is an area for printing by ejecting a liquid from the head unit 51 on the continuum 10 which is a printing medium. The non-printing area is a region on the continuum 10 where the liquid is not discharged from the head unit 51, or a region where the liquid is discharged from the head unit 51 for the purpose of maintenance and recovery. When the cut print medium is continuously conveyed instead of the continuous body, for example, the print medium is the print area, and the area between the preceding print medium and the subsequent print medium is the non-print area. And.

The liquid supply control unit 506 is based on information on the print start, print end, print area, non-print area, detection information (sensor information) of the liquid level sensors 211 and 231, and the like, and the first liquid feed pump 221 of the liquid supply device 200. , The drive control of the second liquid feed pump 202 (control of the liquid feed operation) and the drive control of each part of the liquid supply device 200 are performed to control the liquid supply operation to the head 101 including the circulation of the liquid.

Further, a detection signal from a sensor group 508 composed of various sensors is input to the main control unit 501, and various information is input / output and display information is exchanged with the operation unit 507.

Next, the pressure fluctuation in this liquid supply device (circulation system) will be described with reference to FIG. FIG. 8 is an explanatory diagram provided for the same explanation.

In the liquid supply device described above, for example, when the second liquid feed pump 202 is driven to replenish and feed the liquid from the main tank 201 to the decompression sub tank 210, the liquid which is an incompressible fluid is contained in the decompression sub tank 210. By flowing in, the air layer in the decompression sub-tank 210 is compressed and the pressure rises.

Further, as shown in FIG. 8A, for example, the first liquid feed pump 221 increases the flow rate (liquid feed amount) to be fed by the first liquid feed pump 221 at the time point t1 and decreases it at the time point t2. As shown in FIG. 8B, pressure changes appear on the inlet side (supply side: pressurization side) and outlet side (discharge side: decompression side) of the head 101.

In this way, when the amount of liquid sent by the first liquid feeding pump 221 or the second liquid feeding pump 202 changes, that is, the liquid feeding start (drive start), the liquid feed stop (drive stop), the flow rate increase (acceleration), When the flow rate reduction (deceleration) operation is performed, the amount of inflow and outflow liquids into the decompression subtank 210 and the pressurization subtank 230 changes, and a pressure change occurs in the circulation path 250.

In this case, when the pressure changes, the pressure adjusting mechanism 214 and 234 connected to the decompression sub-tank 210 and the pressurization sub-tank 230 control the pressure to a target pressure and return to a predetermined pressure, but the pressure change itself is suppressed. Can not.

That is, the pressure fluctuation in the circulation path 250 occurs at the timing when the liquid feed amounts of the first liquid feed pump 221 and the second liquid feed pump 202 change. The liquid feed amount of the first liquid feed pump 221 and the second liquid feed pump 202 can be changed by the applied power to the pump (applied voltage, ON / OFF ratio in PWM control, etc.).

Next, the first embodiment of the present invention will be described with reference to FIGS. 9 and 10. FIG. 9 is an explanatory diagram of a region on the continuum used to explain the embodiment, and FIG. 10 is an explanatory diagram of the positional relationship between the region on the continuum and the head unit.

The continuum 10 has a printing area 62A on which the liquid is discharged from the head unit 51, and a non-printing area 62B which is an area other than the area for discharging the liquid for the main purpose of the device such as printing. In the print area 62A, for example, the image 61 is printed. In the non-printing area 62B, the liquid is not discharged from the head unit 51, or empty discharge is performed for the purpose of maintaining and recovering the head 101.

In the following, "do not discharge the liquid for the main purpose" means that the liquid is not discharged from the head unit 51 and the case where the liquid is discharged for the purpose of maintaining and recovering the head.

Here, when the print area 62A of the continuum 10 faces the head unit 51 and discharges the liquid for the main purpose, the “discharge timing” is defined, and the non-print area 62B faces the head unit 51 and discharges the liquid for the main purpose. The time when it is not discharged is defined as "non-discharge timing".

Then, in the present embodiment, for example, as shown in FIG. 10A, the head unit 51 prints an image in the print area 62A1, and as shown in FIG. 10B, the head unit 51 is between the print areas 62A. The amount of liquid sent by the first liquid feeding pump 221 and the second liquid feeding pump 202 is changed when facing the non-printing area 62B1 of.

Similarly, as shown in FIG. 10 (c), the head unit 51 forms an image in the print area 62A2, and as shown in FIG. 10 (d), the head unit 51 forms an image in the non-print area 62B2 between the print areas 62A. When facing each other, the amount of liquid sent by the first liquid feeding pump 221 and the second liquid feeding pump 202 is changed. Similarly, as shown in FIG. 10E, the operation of forming an image in the print area 62A2 by the head unit 51 is repeated.

That is, the liquid feed start (drive start), the liquid feed stop (drive stop), the flow rate increase (acceleration), and the flow rate decrease (deceleration) that change the liquid feed amount of the first liquid feed pump 221 and the second liquid feed pump 202. The operation is performed when the liquid is not discharged from the head unit 51 for the main purpose.

In this way, when the liquid is not discharged from the liquid discharge head for the main purpose, the liquid feed start (drive start) and the liquid feed stop by changing the liquid feed amount by the first liquid feed pump 221 and the second liquid feed pump 202. Control that performs at least one of (drive stop), flow rate increase (acceleration), and flow rate decrease (deceleration), and does not perform at least a part of the operation of changing the liquid feed amount when the liquid is discharged for the main purpose. do. This control is performed by the liquid supply control unit 506 described above.

As a result, the discharge from the liquid discharge head (head unit 51) does not become unstable due to the pressure fluctuation caused by changing the liquid feed amount of the first liquid feed pump 221 and the second liquid feed pump 202, and the main purpose is It is possible to ensure the discharge stability when discharging the liquid.

In this case, at least one of the operations of starting liquid feeding (starting driving), stopping liquid feeding (stop driving), increasing the flow rate (accelerating), and decreasing the flow rate (deceleration) of the first liquid feeding pump 221 and the second liquid feeding pump 202. This operation is performed when the liquid is not discharged from the head unit 51 for the main purpose. At least, the discharge becomes unstable due to the pressure fluctuation accompanying the operation, and the liquid discharge is affected for the main purpose such as print quality. Can be prevented.

As shown in FIG. 8 described above, the pressure fluctuation remains for a while due to the change in the flow rate of the liquid feed pump, so it is best to change the liquid feed amount of the liquid feed pump at the timing of switching from the printed area to the non-printed area. preferable. However, the change in the liquid feed amount of the liquid feed pump (drive start, drive stop, acceleration, deceleration) may be started with a slight delay from the timing of switching from the print area to the non-print area.

Further, although the continuum 10 is used in the present embodiment, it can also be applied to the case of using a printing medium which is a discontinuous member such as cut paper.

In this case, for example, as shown in FIG. 11, the non-printing area 65B between the preceding printing medium 65A1 and the succeeding printing medium 65A2, which are continuously conveyed, becomes the liquid discharge head (head unit 51). Liquid feed start (drive start), liquid feed stop (drive stop), flow rate increase (acceleration) as operations for changing the liquid feed amount of the first liquid feed pump 221 and the second liquid feed pump 202 when facing each other. ), At least one of the flow rate reduction (deceleration) operations is performed.

Next, an example of the decompression sub-tank will be described with reference to FIGS. 12 and 13. FIG. 12 is an explanatory diagram of the decompression sub-tank, and FIG. 13 is an explanatory diagram of an example of the liquid level sensor of the decompression sub-tank.

The liquid (herein referred to as ink 300) sent from the second liquid feeding pump 202 flows into the decompression pump 210 through the liquid inflow tube 1117 and into the decompression sub tank 210. In addition, the ink 300 flows out of the decompression sub-tank 210 through the liquid outflow tube 1118 by the first liquid feed pump 221.

The pressure in the decompression sub-tank 210 is adjusted by the pressure adjusting mechanism 214 through the pressure control port 1119.

Further, a liquid level sensor 211 which is a liquid level detecting means for detecting the state of the liquid level of the ink 300 in the decompression sub-tank 210 is provided. The liquid level sensor 211 is a float sensor, and is a position of a float 1112 movably attached to the stem 1110, a float lower limit stop 1111 and a float upper limit stop 1113 that regulate the movement of the float 1112, and a float 1112 provided on the stem 1110. It has a switch means for turning on / off according to the above.

Here, the detection information (sensor information) of the liquid level sensor 211 will be described with reference to FIGS. 14 and 15. FIG. 14 is an explanatory diagram of the decompression tank used for the same description, and FIG. 15 is an explanatory view of the sensor information.

As shown in FIG. 14A, when the liquid level is lower than the ON / OFF switching position L1 of the liquid level sensor 211, the sensor information of the liquid level sensor 211 is turned off. Further, as shown in FIG. 10B, when the liquid level is above the ON / OFF switching position L1 of the liquid level sensor 211, the sensor information of the liquid level sensor 211 is turned ON.

Then, based on the ON / OFF information of the liquid level sensor 211, the flow rate increasing (acceleration) and the flow rate decreasing (deceleration) of the second liquid feeding pump 202 are performed.

Next, the capacity of the decompression tank 210 when carrying out the present invention will be described.

If the lower side of the liquid outflow tube 1118 is not immersed in the ink 300, the ink 300 cannot be sent to the pressurized sub tank 230. Therefore, the liquid flow rate of the second liquid feed pump 202 is small and the liquid level is in the sensor ON state, but the liquid level drops to the ON / OFF switching position L1 immediately after the non-discharge timing. Even if it does, it is necessary that the ink can be sufficiently supplied to the head 101 until the next non-ejection timing without increasing the liquid feed flow rate of the second liquid feed pump 202.

Therefore, as shown in FIG. 14A, the difference Vh1 (difference in liquid level height h1 × cross-sectional area S) between the amount of ink at the lower end of the liquid outflow tube 1118 and the amount of ink at the ON / OFF switching position L1 is In the time from the non-ejection timing to the next non-ejection timing, a volume larger than the maximum amount of ink that can be fed by the first liquid feeding pump 221 is required.

On the other hand, if the lower side of the pressure control port 1119 comes into contact with the liquid surface, ink invades the pressure control system, causing a failure or deterioration of pressure controllability. Therefore, when the flow rate of the first liquid feed pump 221 is large and the sensor information is OFF, the liquid level rises to the ON / OFF switching position L1 immediately after passing the non-discharge timing. It is necessary that the ink liquid level does not come into contact with the pressure control port 1119 until the next non-ejection timing without reducing the liquid feed amount of the first liquid feed pump 221.

Therefore, the difference VH1 (difference in liquid level height H1 × cross-sectional area S) between the amount of ink at the lower end of the pressure control port 1119 and the amount of ink at the ON / OFF switching position L1 is from the non-ejection timing to the next non-ejection timing. A volume larger than the maximum flow rate that can be fed by the second liquid feeding pump 202 is required at the time of.

Next, an example of the pressurized sub-tank will be described with reference to FIG. FIG. 16 is an explanatory diagram of the pressurized sub tank.

Ink 300, which is a liquid sent from the first liquid feeding pump 221, flows into the pressurized sub tank 230 through the liquid inflow tube 1317 and into the decompressed sub tank 230. Due to the pressure difference from the head 101, the ink 300 flows out of the pressurized sub-tank 230 through the liquid outflow tube 1318.

The pressure in the pressure sub-tank 230 is adjusted by the pressure adjusting mechanism 234 through the pressure control port 1319.

Further, a liquid level sensor 231 which is a liquid level detecting means for detecting the state of the liquid level of the ink 300 in the pressurized sub tank 230 is provided. The liquid level sensor 231 has the same configuration as the liquid level sensor 211.

Here, the detection information (sensor information) of the liquid level sensor 211 will be described with reference to FIGS. 17 and 18. FIG. 17 is an explanatory view of the pressurizing tank used for the same description, and FIG. 18 is an explanatory view of the sensor information.

As shown in FIG. 17A, when the liquid level is below the ON / OFF switching position L3 of the liquid level sensor 231, the sensor information of the liquid level sensor 231 is turned off. Further, as shown in FIG. 17B, when the liquid level is above the ON / OFF switching position L3 of the liquid level sensor 231, the sensor information of the liquid level sensor 231 is turned ON.

Next, the capacity of the pressurizing tank 210 when carrying out the present invention will be described.

If the lower side of the liquid outflow tube 1318 is not immersed in the ink 300, air will be sent to the head 101, which causes a discharge failure. Therefore, the liquid flow rate of the first liquid feed pump 221 is small and the liquid level is in the sensor ON state, but the liquid level drops to the ON / OFF switching position L3 immediately after the non-discharge timing. Even if this happens, it is necessary to be able to sufficiently supply the ink to the head 101 until the next non-ejection timing without increasing the liquid feed flow rate of the first liquid feed pump 221.

Therefore, as shown in FIG. 17A, the difference Vh3 (difference in liquid level h3 × cross-sectional area S) between the amount of ink at the lower end of the liquid outflow tube 1318 and the amount of ink at the ON / OFF switching position L3 is , A volume larger than the maximum discharge amount discharged in the print area is required.

On the other hand, if the lower side of the pressure control port 1319 comes into contact with the liquid surface, ink invades the pressure control system, causing a failure or deterioration of pressure controllability. Therefore, when the flow rate of the first liquid feed pump 221 is large and the sensor information is OFF, the liquid level rises to the ON / OFF switching position L3 immediately after passing the non-discharge timing. It is necessary that the ink liquid level does not come into contact with the pressure control port 1319 until the next non-ejection timing without reducing the liquid feed amount of the first liquid feed pump 221.

Therefore, the difference VH3 (difference in liquid level height H3 × cross-sectional area S) between the amount of ink at the lower end of the pressure control port 1319 and the amount of ink at the ON / OFF switching position L3 is from the non-ejection timing to the next non-ejection timing. A volume larger than the maximum flow rate that can be fed by the second liquid feeding pump 202 is required at the time of.

Next, the drive control of the first liquid feed pump according to the first embodiment of the present invention will be described with reference to the flow chart of FIG.

First, when printing is started, it is determined whether or not printing is completed, and if printing is not completed, the control shifts to the control of the liquid feeding amount of the first liquid feeding pump 221. The first liquid feed pump 221 is driven so as to feed liquid at a predetermined liquid feed amount in order to circulate with the start of printing.

When shifting to the liquid feed amount control, it is determined whether or not the liquid level sensor 231 is in the OFF state. At this time, if the liquid level sensor 231 is not in the OFF state, it stands by as it is.

On the other hand, when the liquid level sensor 231 is turned off, it is determined whether or not the timing is non-discharge. At this time, if it is not the non-discharge timing, it waits as it is.

Then, when the non-discharge timing is reached, the liquid feed amount of the first liquid feed pump 221 is increased (increased).

After that, it is determined whether or not the liquid level sensor 231 is in the ON state. At this time, if the liquid level sensor 231 is not in the ON state, it stands by as it is.

On the other hand, when the liquid level sensor 231 is turned on, it is determined whether or not the timing is non-discharge. At this time, if it is not the non-discharge timing, it waits as it is.

Then, when the non-discharge timing is reached, the liquid feed amount of the first liquid feed pump 221 is reduced (decreased).

Next, the drive control of the second liquid feed pump according to the first embodiment of the present invention will be described with reference to the flow chart of FIG.

First, when printing is started, it is determined whether or not printing is completed, and if printing is not completed, the control shifts to the control of the liquid feeding amount of the second liquid feeding pump 202. The second liquid feed pump 202 is driven so as to feed the liquid at a predetermined liquid feed amount in order to perform circulation at the start of printing.

When shifting to the liquid feed amount control, it is determined whether or not the liquid level sensor 211 is in the OFF state. At this time, if the liquid level sensor 211 is not in the OFF state, it stands by as it is.

On the other hand, when the liquid level sensor 211 is turned off, it is determined whether or not the timing is non-discharge. At this time, if it is not the non-discharge timing, it waits as it is.

Then, when the non-discharge timing is reached, the liquid feed amount of the second liquid feed pump 202 is increased (increased).

After that, it is determined whether or not the liquid level sensor 211 is in the ON state. At this time, if the liquid level sensor 211 is not in the ON state, it stands by as it is.

On the other hand, when the liquid level sensor 211 is turned on, it is determined whether or not the timing is non-discharge. At this time, if it is not the non-discharge timing, it waits as it is.

Then, when the non-discharge timing is reached, the liquid feed amount of the second liquid feed pump 202 is reduced (decreased).

Next, the second embodiment of the present invention will be described with reference to FIGS. 21 and 22. FIG. 21 is a flow chart for explaining the setting of the acceleration / deceleration speed of the liquid feed pump in the same embodiment, and FIG. 22 is an explanatory diagram for explaining the relationship between the acceleration / deceleration time and the non-printing area.

In the present embodiment, the transfer speed of the continuous body 10 is taken in, the acceleration / deceleration profile of the first liquid feed pump 221 is set (including selection) according to the taken-in transport speed, and the second liquid feed pump 202 is added. Set the deceleration profile (including selection).

That is, in the acceleration (increase) and deceleration (decrease) operations of changing the liquid feed amount of the first liquid feed pump 221 and the second liquid feed pump 202, the head unit 51 faces the non-printing area of the continuum 10. It is preferable that it is completed within the required time.

On the other hand, the time during which the head unit 51 faces the non-printing area of the continuous body 10 changes depending on the transport speed of the continuous body 10.

Therefore, in the present embodiment, the transfer speed of the print medium is taken in, and the acceleration / deceleration profile is changed according to the transfer speed to change the liquid feed amount of the first liquid feed pump 221 and the second liquid feed pump 202. The acceleration (increase) time Tacc and the deceleration (decrease) time Tdec to be caused are set to be shorter than the time when the head unit 51 faces the non-printing area of the continuum 10.

As a result, even when the printing speed of the printing medium is changed (when the transport speed is changed), acceleration (increase) and deceleration (increasing) and deceleration (increasing) and deceleration (increasing) and deceleration (increasing) and deceleration (increasing), which change the liquid feeding amount of the first liquid feeding pump 221 and the second liquid feeding pump 202 The operation of (decrease) is completed within the time when the head unit 51 faces the non-printing area of the continuum 10, and the ejection stability when ejecting the liquid for the main purpose can be ensured.

Next, another example of the liquid supply device according to the present invention will be described with reference to FIG. FIG. 23 is a block explanatory view of a portion related to the liquid supply device.

The liquid supply device 800 includes a main tank 801 and a replenishment pump 813 which is a fifth liquid feeding means, an intermediate sub tank 811 and a pressurized sub tank 821, a decompression sub tank 871, and a pressurized liquid feeding pump 822 and a fourth feeding means which are the third liquid feeding means. It is provided with a decompression liquid feeding pump 872, a pressurization head tank 851, a decompression head tank 852, and the like, which are liquid means.

In the intermediate sub tank 821, the liquid is sent from the main tank 801 which is a liquid storage means for storing the liquid discharged from the head 101 by the replenishment pump 813. The replenishment pump 813 is driven based on the detection result of the liquid level detecting means 812 that detects the liquid level of the intermediate sub tank 811.

Liquid is sent to the pressurized sub tank 821 from the intermediate sub tank 811 side by the pressurized liquid feeding pump 822. A degassing module 831 is interposed between the pressurized liquid feed pump 822 and the pressurized sub tank 821, and the vacuum pump 832 is connected to the degassing module 831.

The pressurizing sub-tank 821 is pressurized to a target pressure by receiving liquid feed from a pressurized liquid feed pump 822 driven based on the pressure detection information of the pressurized hydraulic pressure gauge 841.

The pressurized hydraulic pressure gauge 841 detects the pressure in the flow path leading to the head 101 (the flow path between the pressurized sub tank 821 and the pressurized head tank 851), and the detection result (pressure) obtained by the pressurized hydraulic pressure gauge 841. The detection information) is input to the control unit (control means) that drives and controls the pressurized liquid feed pump 822. A pressurizing side flow path valve 824 is provided in the flow path between the pressurizing sub tank 821 and the pressurizing head tank 851.

The pressurized liquid feed pump 822 is driven by the control unit when the detected pressure detected by the pressurized hydraulic pressure gauge 841 becomes lower than a predetermined threshold value, and feeds liquid from the intermediate sub tank 811 to the pressurized sub tank 821. As a result, the pressurized sub tank 821 is pressurized to the target pressure.

Liquid is sent to the intermediate sub tank 811 side of the decompression sub tank 871 by the decompression pump 872.

The decompression sub-tank 871 is depressurized to the target pressure by the decompression pump 872 driven based on the pressure detection information of the decompression hydraulic pressure gauge 842.

The decompression hydraulic pressure gauge 842 detects the pressure in the flow path leading to the head 101 (the flow path between the decompression head tank 852 and the decompression sub tank 871), and the detection result (pressure detection information) obtained by the decompression hydraulic pressure gauge 842 is It is input to the control unit (control means) that drives and controls the decompression liquid feed pump 872. A decompression side flow path valve 874 is provided in the flow path between the decompression head tank 852 and the decompression sub tank 871.

The decompression liquid feed pump 872 is driven by the control unit when the detection pressure detected by the decompression hydraulic pressure gauge 842 becomes higher than a predetermined threshold value, and the liquid is fed from the decompression sub tank 872 to the intermediate sub tank 811. As a result, the decompression sub-tank 871 is decompressed to the target pressure.

In the liquid supply device 800, the circulation path 850 is configured by the intermediate sub tank 811, the pressurized sub tank 821, the pressurized head tank 851, the head 101, the decompressed head tank 852, and the decompressed sub tank 871. The pressurizing side liquid feeding pump 822 and the depressurizing side liquid feeding pump 872 send the liquid in the circulation path 850, and the replenishment pump 813 sends the liquid to the circulation path 850.

A pressure difference is given between the decompression subtank 871 and the pressurization subtank 821, and the pressure difference causes the pressurization subtank 821 to pass through the pressurization head tank 851, the head 101, and the decompression head tank 852 to reduce the pressure. Liquid flows to the sub tank 871.

When ink flows from the pressurized sub-tank 821 to the decompressed sub-tank 871 due to the pressure difference, the pressure of the pressurized sub-tank 821 decreases. When the pressurizing hydraulic pressure gauge 841 detects a decrease in pressure and the pressure becomes lower than the threshold value, the pressurizing pump 822 operates to replenish the ink from the intermediate sub tank 811 to the pressurizing sub tank 821 to pressurize the ink.

Similarly, when ink flows from the pressurized sub tank 821 to the decompressed sub tank 871 due to the pressure difference, the pressure of the decompressed sub tank 871 rises (negative pressure weakens). The decompression hydraulic pressure gauge 842 detects a decrease in pressure and the decompression liquid feed pump 872 becomes a pressure higher than the threshold value, and ink is discharged from the decompression sub-tank 871 to the intermediate sub-tank 811 to reduce the pressure.

In this way, the liquid (ink) is circulated in the circulation path 850.

Here, when the ink is not consumed by the head 101 for ejection or the like, the amount of ink in the intermediate sub tank 811 does not change significantly. On the other hand, when the ink is consumed by the head 101 for ejection or the like, the amount of ink in the intermediate sub tank 811 decreases, and the decrease in the amount of ink is detected by the liquid level sensor 812 or the like and replenished from the main tank 801. Ink is sent to the intermediate sub tank 811 by the pump 813 to replenish the ink.

In the present application, the "liquid" to be discharged may have a viscosity and surface tension that can be discharged from the head, and is not particularly limited, but has a viscosity of 30 mPa · s or less at room temperature, under normal pressure, or by heating or cooling. It is preferable that More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, polymerizable compounds, resins, functionalizing materials such as surfactants, biocompatible materials such as DNA, amino acids and proteins, and calcium. , Solvents, suspensions, emulsions, etc. containing edible materials such as natural dyes, etc., for example, inks for inkjets, surface treatment liquids, constituents of electronic elements and light emitting elements, and formation of electronic circuit resist patterns. It can be used for applications such as liquids for three-dimensional modeling.

The "liquid discharge head" includes a piezoelectric actuator (laminated piezoelectric element and thin film piezoelectric element), a thermal actuator that uses an electrothermal conversion element such as a heat generating resistor, a vibrating plate and a counter electrode as an energy generation source for discharging liquid. Includes those that use electrostatic actuators and the like.

The "device for discharging a liquid" includes a device for driving a liquid discharge head to discharge a liquid. The device for discharging the liquid includes not only a device capable of discharging the liquid to a device to which the liquid can adhere, but also a device for discharging the liquid into the air or the liquid.

The "device for discharging the liquid" can also include means for feeding, transporting, and discharging paper to which the liquid can adhere, as well as a pretreatment device, a posttreatment device, and the like.

For example, as a "device that ejects a liquid", an image forming device that is a device that ejects ink to form an image on paper, and a powder is formed in layers in order to form a three-dimensional model (three-dimensional model). There is a three-dimensional modeling device (three-dimensional modeling device) that discharges the modeling liquid into the powder layer.

Further, the "device for discharging a liquid" is not limited to a device in which a significant image such as characters and figures is visualized by the discharged liquid. For example, those that form patterns that have no meaning in themselves and those that form a three-dimensional image are also included.

The above-mentioned "material to which a liquid can adhere" means a material to which a liquid can adhere at least temporarily, such as one that adheres and adheres, and one that adheres and permeates. Specific examples include media such as paper, recording paper, recording paper, film, cloth and other recording media, electronic substrates, electronic components such as piezoelectric elements, powder layers (powder layers), organ models, and inspection cells. Yes, including anything to which the liquid adheres, unless otherwise specified.

The material of the above-mentioned "material to which liquid can be attached" may be paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics or the like as long as the liquid can be attached even temporarily.

Further, the "device for discharging the liquid" includes, but is not limited to, a device in which the liquid discharge head and the device to which the liquid can adhere move relatively. Specific examples include a serial type device that moves the liquid discharge head, a line type device that does not move the liquid discharge head, and the like.

In addition, as a "device for ejecting a liquid", a treatment liquid coating device for ejecting a treatment liquid to the paper in order to apply the treatment liquid to the surface of the paper for the purpose of modifying the surface of the paper, etc. There is an injection granulator that injects a composition liquid in which a raw material is dispersed in a solution through a nozzle to granulate fine particles of the raw material.

In addition, image formation, recording, printing, printing, printing, modeling, etc. in the terms of the present application are all synonymous.

5 Printing means 10 Continuum 50 Liquid ejection unit 51 Head unit 100 Printing device (device that ejects liquid)
101 Liquid discharge head (head)
200 Liquid supply device 201 Main tank (liquid storage means)
202 Second liquid feed pump (liquid feed means)
210 Decompression sub-tank 211 Liquid level sensor 213 Vacuum pump (gas pump)
214 Pressure adjustment mechanism (pressure adjustment means)
221 First liquid feed pump (liquid feed means)
230 Pressurization / decompression sub-tank 231 Liquid level sensor 233 Compressor (gas pump)
244 Pressure adjustment mechanism (pressure adjustment means)
250 Circulation path 500 Output control device 600 High-end device 800 Liquid supply device 811 Intermediate sub-tank 813 Replenishment pump (fifth liquid feeding means)
821 Pressurized sub-tank 822 Pressurized liquid feed pump (third liquid feed means)
850 Circulation path 871 Decompression sub-tank 872 Decompression liquid feed pump (4th liquid feed means)

Claims (9)

A circulation path in which the liquid circulates through a liquid discharge head that discharges the liquid to the printed medium to be conveyed .
At least one of a liquid feeding means for sending the liquid in the circulation path and a liquid feeding means for sending the liquid to the circulation path.
The liquid feeding control means for controlling the liquid feeding operation of the liquid feeding means is provided.
The liquid feed control means
The operation of changing the liquid feeding amount of the liquid feeding means is at least when the liquid is not discharged from the liquid discharging head and when the liquid is discharged from the liquid discharging head for the purpose of maintaining and recovering the liquid discharging head. the control carried out either,
A device for discharging a liquid, which comprises changing the time for changing the liquid feeding amount of the liquid feeding means according to the conveying speed of the printing medium . The device for discharging a liquid according to claim 1, wherein the operation of changing the liquid feeding amount of the liquid feeding means is at least one of an acceleration operation and a deceleration operation when driving the liquid feeding means. .. The operation of changing the feeding amount before Kiokueki means, a liquid according to claim 1 or 2, wherein the liquid ejection head in the non-printing area of the print medium and performing when facing Discharge device. The operation of changing the liquid feeding amount of the liquid feeding means is when the liquid discharging head faces the non-printing area between the preceding printing medium and the succeeding printing medium which are continuously conveyed . The device for discharging a liquid according to claim 1 or 2, wherein the liquid is discharged. The device for discharging a liquid according to claim 3 or 4, wherein the time for changing the liquid feeding amount of the liquid feeding means is shorter than the time for the liquid discharging head to face the non-printing area. .. The circulation route is
A pressurized sub-tank connected to the liquid discharge head and
A decompression sub-tank connected to the liquid discharge head and
The first liquid feeding means for feeding liquid from the decompression sub-tank to the pressurizing sub-tank is included.
A liquid storage means for storing the liquid and
A second liquid feeding means for feeding the liquid from the liquid storing means to the decompression sub-tank,
A gas pump and pressure adjusting means for adjusting the pressurized sub-tank to a predetermined pressure,
The device for discharging a liquid according to any one of claims 1 to 5 , further comprising a gas pump for adjusting the decompression sub-tank to a predetermined pressure and a pressure adjusting means. The circulation route is
A pressurized sub-tank connected to the liquid discharge head and
A decompression sub-tank connected to the liquid discharge head and
An intermediate subtank arranged between the decompression subtank and the pressurization subtank,
A third liquid feeding means for feeding liquid from the intermediate sub tank to the pressurized sub tank,
A fourth liquid feeding means for feeding liquid from the decompression sub-tank to the intermediate sub-tank is included.
A liquid storage means for storing the liquid and
A fifth liquid feeding means for feeding the liquid from the liquid storing means to the intermediate sub-tank,
The device for discharging the liquid according to any one of claims 1 to 5 , wherein the liquid is discharged. A circulation path in which the liquid circulates through a liquid discharge head that discharges the liquid to the printed medium to be conveyed .
At least one of a liquid feeding means for sending the liquid in the circulation path and a liquid feeding means for sending the liquid to the circulation path.
The liquid feeding control means for controlling the liquid feeding operation of the liquid feeding means is provided.
The liquid feed control means
The operation of changing the liquid feeding amount of the liquid feeding means is at least when the liquid is not discharged from the liquid discharging head and when the liquid is discharged from the liquid discharging head for the purpose of maintaining and recovering the liquid discharging head. the control carried out either,
A liquid supply device, characterized in that the time for changing the liquid feed amount of the liquid feed means is changed according to the transport speed of the print medium . The liquid is supplied to the liquid discharge head while circulating the liquid through the liquid discharge head that discharges the liquid to the printed medium to be conveyed .
Feeding means for feeding the liquid in the circulation path in which the liquid is circulated, and the operation of changing either the feed volume less liquid feeding means for feeding the liquid to the circulation path, the liquid when the discharge head does not eject the liquid, and, have at least a row at one of time of ejecting the liquid from said liquid discharge head maintenance or recovery purposes of the liquid discharge head,
A liquid supply method, characterized in that the time for changing the liquid feed amount of the liquid feed means is changed according to the transport speed of the print medium .

Images