JP2005288769A - Liquid ejecting apparatus and liquid ejecting apparatus cleaning method - Google Patents

Abstract

To provide a liquid ejecting apparatus and a liquid ejecting apparatus cleaning method capable of accurately measuring the viscosity of ink with a simple configuration.
SOLUTION: A suction means 11 that sucks liquid from a liquid jet head 30 in contact with a nozzle surface 61, a pressure measuring means 13 that measures a pressure inside the suction means 11, and a suction means 11 that sucks liquid. The negative pressure extinction time measuring means for measuring the negative pressure extinction time until the atmospheric pressure in the suction means 11 becomes substantially equal to the atmospheric pressure after the stop of the vacuum, and the negative pressure extinction indicating the relationship between the liquid viscosity and the negative pressure extinction time Based on the time viscosity information, the viscosity determining means for determining the viscosity of the liquid, the negative pressure release time from when the suction means 11 stops sucking the liquid until the contact with the nozzle surface 61 of the suction means 11 is released, and Negative pressure release time setting means 100 for setting the negative pressure release time based on the viscosity negative pressure release time information indicating the relationship of the viscosity.
[Selection] Figure 6

Description

  The present invention relates to a liquid ejecting apparatus that ejects liquid and a cleaning method for the liquid ejecting apparatus.

  As a liquid ejecting apparatus that ejects liquid onto a target, an ink jet recording apparatus that performs printing by ejecting ink droplets from a recording head onto a recording medium is known. Such an ink jet recording apparatus records an image such as a desired character or graphic by ejecting minute ink droplets from a nozzle of a recording head onto a recording medium.

An ink jet recording apparatus includes an ink jet recording head that receives ink supplied from an ink cartridge, and a paper feeding unit that moves the recording paper relative to the recording head. Recording is performed by ejecting ink droplets onto the recording paper while moving in the direction.
For example, a black recording head that discharges black ink and a color recording head that can discharge yellow, cyan, and magenta inks are mounted on a common carriage. Full color printing is made possible by changing the ink ejection ratio.

In such an ink jet recording apparatus, a cleaning process, which is a forced ink discharge process, is performed in order to eliminate clogging of the recording head. This cleaning process is performed by bringing a cap into contact with the recording head and generating a negative pressure in the cap with a suction pump to forcibly eject ink from the recording head. After the cleaning is completed, the contact of the cap with the recording head is released after the passage of time until the atmospheric pressure in the cap becomes equal to the atmospheric pressure (negative pressure extinction time). The negative pressure extinction time varies depending on the viscosity of the ink, and for example, the negative pressure extinction time increases as the ink viscosity increases.
In this regard, a technique for measuring the viscosity of ink by arranging a viscosity sensor in the ink path in the recording head has been proposed (for example, Patent Document 1).
JP 2000-343705 A (FIG. 5 etc.)

However, if the viscosity sensor is arranged in the recording head, the configuration of the recording head becomes complicated. The viscosity sensor measures the viscosity based on the electrical resistance of the ink that varies depending on the viscosity. However, the electrical resistance of the ink varies depending not only on the viscosity of the ink but also on other factors such as the ink components.
Therefore, the conventional technology has a problem that the configuration of the recording head is complicated and the viscosity of the ink cannot be measured accurately.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a liquid ejecting apparatus and a liquid ejecting apparatus cleaning method capable of accurately measuring the viscosity of ink while solving the above problems and having a simple configuration.

  According to the first aspect of the present invention, there is provided a liquid ejecting head having a nozzle surface that ejects liquid, a suction unit that contacts the nozzle surface and sucks the liquid from the liquid ejecting head with negative pressure, A pressure measuring means for measuring the pressure in the suction means, and a negative pressure for measuring a negative pressure extinction time from when the suction means stops sucking the liquid until the pressure in the suction means becomes substantially equal to the atmospheric pressure. Disappearance time measuring means, viscosity determination means for determining the viscosity of the liquid based on negative pressure extinction time viscosity information indicating the relationship between the viscosity of the liquid and the negative pressure extinction time, and the suction means for suctioning the liquid The negative pressure release time is set based on viscosity negative pressure release time information indicating the relationship between the viscosity and the negative pressure release time from when the suction means is released to contact with the nozzle surface. Release time It is achieved by a liquid-jet apparatus characterized by having a constant section.

  According to the configuration of the first aspect of the invention, the liquid ejecting apparatus measures the negative pressure extinction time from when the suction means stops sucking the liquid until the atmospheric pressure in the suction means becomes substantially equal to the atmospheric pressure. Then, the viscosity of the liquid is determined based on the negative pressure extinction time viscosity information indicating the relationship between the viscosity of the liquid and the negative pressure extinction time.

When the suction means stops sucking the liquid, the air pressure in the suction means is lower than the external atmospheric pressure. That is, the suction means is in a negative pressure state.
Then, the liquid flows into the suction means from the nozzle surface until the negative pressure state in the suction means is eliminated and the atmospheric pressure in the suction means becomes substantially equal to the atmospheric pressure.
According to the structure of this invention, a viscosity is judged by measuring the negative pressure extinction time until a negative pressure state is eliminated.
For this reason, since the liquid ejecting head does not have a configuration for determining the viscosity of the liquid, a special configuration is not necessary for the liquid ejecting head. Therefore, the configuration can be simplified.
In addition, the viscosity of the liquid can be determined not based on the electric resistance of the liquid but based on the relationship with the negative pressure extinction time. This means that the viscosity can be determined regardless of the components of the liquid, and the accurate viscosity of the liquid can be determined.
Accordingly, the liquid ejecting apparatus can accurately measure the viscosity of the liquid with a simple configuration.

Furthermore, the liquid ejecting apparatus is configured to release the negative viscosity indicating the relationship between the negative pressure release time from when the suction means stops sucking the liquid until the suction means releases the contact with the nozzle surface and the viscosity. Based on the time information, the negative pressure release time is set.
The negative pressure release time requires a long time if the viscosity of the liquid is large, and a short time is sufficient if the viscosity of the liquid is small. That is, the appropriate negative pressure release time varies depending on the viscosity of the liquid.
In this regard, according to the configuration of the present invention, as described above, the viscosity of the liquid can be accurately measured, so that an appropriate negative pressure release time can also be accurately set.

  The second invention is characterized in that, in the configuration of the first invention, the negative pressure extinction time measuring means determines whether or not the atmospheric pressure in the suction means has become substantially constant.

If a negative pressure remains in the suction means, the liquid flows into the suction means from the nozzle surface of the liquid jet head. The inflow of the liquid continues until the atmospheric pressure in the suction means becomes substantially equal to the atmospheric pressure. As long as the inflow of the liquid continues, the air pressure in the suction means varies.
For this reason, when the atmospheric pressure in the suction means becomes substantially constant, it can be said that the atmospheric pressure in the suction means is substantially equal to the atmospheric pressure.
As a result, it is possible to determine whether or not the pressure in the suction means has become substantially equal to the atmospheric pressure by determining whether or not the pressure in the suction means has become substantially constant.

  According to a third aspect of the present invention, in the configuration of the first aspect or the second aspect of the invention, the atmospheric pressure measurement unit is configured to detect the nozzle surface when the suction unit contacts the nozzle surface in the suction unit. It is arranged at a position near the nozzle surface that is in the vicinity.

After the suction of the liquid in the suction means stops, the liquid does not flow out of the suction means, but the liquid flows into the suction means from the nozzle surface.
For this reason, if the atmospheric pressure measuring means is disposed at a position opposite to the position near the nozzle surface in the altitude direction, the atmospheric pressure measuring means can be buried in the liquid in the suction means, and the atmospheric pressure can be accurately measured. Disappear.
In this regard, according to the configuration of the present invention, since the atmospheric pressure measuring means is disposed in the vicinity of the nozzle surface, the atmospheric pressure can be accurately measured without being buried in the liquid.

  According to a fourth aspect of the present invention, there is provided the liquid suction step in which the suction means of the liquid ejecting apparatus contacts the nozzle surface of the liquid ejecting head that ejects the liquid and sucks the liquid from the liquid ejecting head with a negative pressure. And the negative pressure extinction time measuring means of the liquid ejecting apparatus measures the negative pressure extinction time from when the suction means stops sucking the liquid until the atmospheric pressure in the suction means becomes substantially equal to the atmospheric pressure. Viscosity in which the negative pressure extinction time measuring step and the viscosity determining means of the liquid ejecting apparatus determine the viscosity of the liquid based on the negative pressure extinction time viscosity information indicating the relationship between the viscosity of the liquid and the negative pressure extinction time. And a negative pressure release time setting unit between the determination unit and the negative pressure release time setting unit of the liquid ejecting apparatus from when the suction unit stops sucking the liquid until the suction unit releases contact with the nozzle surface. Based on the viscosity NP remove time information indicating the relationship of the viscosity is achieved by the cleaning method of the liquid ejecting apparatus comprising: the negative pressure releasing time setting step of setting the negative pressure release time, the.

  According to the configuration of the fourth invention, similarly to the first invention, the viscosity of the liquid can be accurately measured with a simple configuration. Moreover, since the viscosity of the liquid can be accurately measured, an appropriate negative pressure release time can be set accurately.

  In a fifth aspect based on the fourth aspect, in the negative pressure extinction time measuring step, the negative pressure extinction time measuring means determines whether or not the atmospheric pressure in the suction means has become substantially constant. It is characterized by that.

  According to the fifth aspect of the invention, as in the second aspect of the invention, by determining whether or not the atmospheric pressure in the suction means has become substantially constant, the atmospheric pressure in the suction means is substantially equal to the atmospheric pressure. It can be determined whether or not.

Preferred embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows an ink jet recording apparatus 10 which is a preferred embodiment of the liquid ejecting apparatus of the present invention. The ink jet recording apparatus 10 is a so-called off-carriage recording apparatus in which an ink cartridge and a recording head are connected by an ink supply tube.
The ink jet recording apparatus 10 illustrated in FIG. 1 is an example of a liquid ejecting apparatus as described above, but the ink jet recording apparatus 10 includes a main body 10A. The main body 10A includes a carriage 1, a carriage motor 2, a timing belt 3, a scanning guide member 4, a paper transport mechanism unit 5, a cartridge holder 8, an ink suction device 11, and a wiping member 12.

The carriage 1 holds a recording head 30. The carriage 1 is attached to the timing belt 3. The timing belt 3 is moved endlessly by the carriage motor 2. Accordingly, the carriage 1 can be reciprocated along the main scanning direction T via the timing belt 3 by driving the carriage motor 2. This main scanning direction T is the paper width direction which is the longitudinal direction of the paper transport mechanism section 5.
The paper transport mechanism unit 5 is a mechanism for transporting paper, which is an example of a target medium that ejects ink, in a direction perpendicular to the main scanning direction T. The recording head 30 faces the sheet conveyed by the sheet conveying mechanism unit 5. The recording head 30 is an example of a liquid ejecting head having a nozzle surface that ejects liquid, and is also called a print head or a print head.

The cartridge holder 8 shown in FIG. 1 holds, for example, four ink cartridges 9A, 9B, 9C, 9D. The ink cartridges 9A, 9B, 9C, and 9D are examples of a liquid storage unit that stores liquid. Various inks used in the ink jet recording apparatus 10 are examples of liquids.
In the example of FIG. 1, four ink cartridges are mounted on the cartridge holder 8, but this number is not particularly limited.
For example, the ink cartridge 9A stores black ink, and the ink cartridge 9B stores yellow ink. The ink cartridge 9C stores magenta ink, and the ink cartridge 9D stores cyan ink.

The ink cartridges 9A to 9D have, for example, the following structure. Each ink cartridge 9A to 9D accommodates an ink pack formed of a flexible material in which ink is sealed.
Pressurized air generated by the pressurizing pump 21 is supplied into the ink cartridges 9A, 9B, 9C, and 9D via the connection passages 27A, 27B, 27C, and 27D via the pressure adjusting valve 22H and the pressure detector 23. it can. Any one or more of the ink cartridges 9A to 9D to which the pressurized air is supplied can send the ink in the ink pack inside thereof to the tubes 20A, 20B, 20C, and 20D through the ink supply valve 26. .

  These tubes 20 </ b> A, 20 </ b> B, 20 </ b> C, and 20 </ b> D are examples of liquid passages that supply ink to the recording head 30. The tubes 20A to 20D are made of, for example, a flexible material. The upstream end side of the tubes 20A to 20D is connected to the ink supply valve 26. The downstream end side of the tubes 20A to 20D is connected to the recording head 30.

The ink suction device 11 and the wiping member 12 shown in FIG. 1 are arranged in a non-printing area (also called a home position) HP with respect to the main scanning direction T of the carriage 1.
The ink suction device 11 is also called a capping device, and is an example of a suction unit that touches the nozzle surface of the recording head 30 and sucks ink such as the recording head 30 and the tube 20 </ b> A by negative pressure. The ink suction device 11 has a cap body 15. The cap body 15 is made of a flexible material that can be sealed by contacting the nozzle plate surface of the recording head 30. When the carriage 1 moves to the non-printing area HP, the cap body 15 follows this to seal the nozzle plate surface of the recording head 30.

Next, an example of the structure of the recording head 30 shown in FIG. 1 will be described with reference to FIGS.
2 and 3 show a structural example of the recording head 30 and a structural example of the ink suction device 11. FIG. 4 shows an example of the shape of the nozzle plate surface 61 of the recording head 30 as viewed from the direction E in FIG. FIG. 5 shows an example of the internal structure including the piezoelectric vibrator of the recording head 30.
As shown in FIG. 2, the recording head 30 has a nozzle plate surface 61 on its lower surface. The nozzle plate surface 61 is an example of a nozzle surface. The nozzle plate surface 61 is the lower surface of the nozzle plate 62. The nozzle plate 62 has nozzle opening rows 54A to 54D as shown in FIG.

  FIG. 4 shows an arrangement example of the nozzle opening rows 54A to 54D. The nozzle opening rows 54A to 54D are formed in parallel with the U direction and have a predetermined interval in the T direction. The nozzle opening row 54A includes a plurality of nozzle openings 55A. Similarly, the nozzle opening rows 54B, 54C, and 54D are constituted by a plurality of nozzle openings 55B, 55C, and 55D, respectively.

The recording head 30 shown in FIG. 2 has an ink path 50 and a pressure chamber 51. The ink path 50 is connected to the nozzle openings 55A to 55D through the pressure chamber 51 as shown in FIG. Each ink path 50 is connected to the downstream end 20E of the tubes 20A to 20D, which are also shown in FIG.
Accordingly, the four types of ink are supplied to the ink path 50 through the tubes 20A to 20D shown in FIG. In FIG. 5, each ink supplied from the above-described tube is supplied to the pressure chamber 51 through the ink path 50.
At the time of printing, the piezoelectric vibrator 39 as a pressure generating element expands and contracts, thereby changing the volume of the pressure chamber 51 and causing pressure fluctuation in the ink in the pressure chamber 51. As a result, ink droplets can be ejected (also referred to as ejection) from the nozzle openings 55A to 55D.

Next, an example of the structure of the ink suction device 11 shown in FIG. 1 will be described with reference to FIGS.
2 and 3, the recording head 30 is positioned at the home position HP shown also in FIG. Thus, when the recording head 30 is positioned at the home position HP, the nozzle plate surface 61 of the recording head 30 and the ink suction device 11 face each other. The ink suction device 11 is located below the nozzle plate surface 61. The ink suction device 11 includes a cap body 15, an absorbent material 22, and a suction pump 19.

The cap body 15 is preferably made of a material that elastically deforms when it is in close contact with or pressure-bonded to the nozzle plate surface 61 as shown in FIG. The cap main body 15 is a box-shaped member having a bottom portion and four side surfaces, for example, and an absorbent material 22 is accommodated in the cap main body 15. The absorbent 22 is desirably made of a hydrophilic material such as foamed plastic.
The discharge part 13A of the cap body 15 is connected to the suction pump 19 through the discharge tube 19A.

As shown in FIG. 2, a negative pressure sensor 13, which is an example of an atmospheric pressure measuring unit that measures the atmospheric pressure in the ink suction device 11, is disposed on the side surface portion 11 a of the cap body 15. The negative pressure sensor 13 is a semiconductor sensor, for example.
In the ink suction device 11, the negative pressure sensor 13 is disposed on the side surface portion 11 a that is in the vicinity of the nozzle surface that is in the vicinity of the nozzle plate surface 61 when the ink suction device 11 contacts the nozzle plate surface 51.

After the ink suction device 11 stops sucking ink, ink does not flow out from the ink suction device 11, but ink flows into the ink suction device 11 from the nozzle plate surface 61.
For this reason, when the negative pressure sensor 13 is disposed, for example, on the bottom surface portion 11b that is opposite to the position near the nozzle plate surface 61 in the altitude direction, the negative pressure sensor 13 is buried in the ink in the ink suction device 11, and the atmospheric pressure is It becomes impossible to measure accurately.
In this respect, according to the configuration of the present embodiment, since the negative pressure sensor 13 is disposed in the vicinity of the nozzle plate surface 61, it is not buried in the ink and can accurately measure the atmospheric pressure. is there.

The elevating device 250 can raise the cap body 15 in the Z2 direction from the standby state shown in FIG. 2 to the suction state shown in FIG.
When the suction pump 19 is operated in the state of FIG. 3, a negative pressure is generated in the ink suction device 11, and the recording head 30 and the tube 20 </ b> A etc. (see FIG. 1) through the nozzle plate surface 61 and the absorber 22. Can be forcibly discharged to the waste ink tank 120 side.

The ink suction device 11 functions as a lid that prevents the nozzle opening from being dried by sealing the nozzle plate surface of the recording head 30 during a period in which the ink jet recording device 10 is at rest. The ink suction device 11 can perform a cleaning operation for sucking and discharging ink from the nozzle openings on the nozzle plate surface of the recording head 30 by applying a negative pressure by a suction pump described later.
The wiping member 12 shown in FIG. 1 is made of an elastic material such as rubber. When the recording head 30 has moved to the home position HP, the wiping member 12 can be cleaned by mechanically wiping (wiping) the nozzle plate surface of the recording head 30.

Reference is now made to FIG. FIG. 6 shows a main electrical connection example and the host computer 40 of the ink jet recording apparatus 10 shown in FIG.
6 includes a control device 100, an ink suction device 11 having a suction pump 12 and a negative pressure sensor 13, and a clock 14. The control device 100 has negative pressure extinction time measurement control information 46 (see FIG. 6), which will be described later, and the pressure in the ink suction means after the ink ink suction device 11 stops sucking ink by the clock 14 is atmospheric pressure. It is an example of a negative pressure extinction time measuring means for measuring the negative pressure extinction time until it becomes substantially equal to.

The ink jet recording apparatus 10 of FIG. 4 also includes a recording head 30, a carriage motor 2, and a paper transport mechanism unit 5.
The control device 100 is connected to the printer driver 41 of the host computer 40 via, for example, a local printer cable or a communication network. The printer driver 41 includes software that sends a command for causing the control device 100 to execute a printing, cleaning operation, or suction operation.

As shown in FIG. 6, the control device 100 has an information file 43, which stores negative pressure time setting cleaning judgment information 45 and the like.
The negative pressure time setting cleaning judgment information 45 is a negative pressure time setting for the control device 100 to set a negative pressure release time for the next and subsequent cleanings of the recording head 30 and the tube 20A in FIG. This is information for determining whether the cleaning is normal cleaning or normal cleaning other than negative pressure time setting cleaning.

The negative pressure extinction time measurement control information 46 is suctioned to measure the negative pressure extinction time when the control device 100 determines that the negative pressure time setting cleaning is based on the negative pressure time setting cleaning judgment information 45. Information for controlling the pump 12, the negative pressure sensor 13, and the timepiece 14.
Specifically, based on the negative pressure extinction time measurement control information 46, the control device 100 starts measuring the atmospheric pressure in the ink suction device 11 with the negative pressure sensor 13 after the suction pump 12 stops driving. The start time is acquired by the clock 14.

Then, the control device 100 confirms by the negative pressure sensor 13 that the atmospheric pressure in the ink suction device 11 is substantially equal to the atmospheric pressure (the negative pressure has disappeared). At this time, the control device 100 determines the disappearance of the negative pressure by determining whether or not the atmospheric pressure in the ink suction device 11 has become substantially constant.
When negative pressure remains in the ink suction device 11, ink flows into the ink suction device 11 from the nozzle plate surface 61 of FIG. 2. The inflow of ink continues until the atmospheric pressure in the ink suction device 11 becomes substantially equal to the atmospheric pressure. As long as the inflow of ink continues, the air pressure in the ink suction device 11 varies.
For this reason, when the atmospheric pressure in the ink suction device 11 becomes substantially constant, it can be said that the atmospheric pressure in the ink suction device 11 is substantially equal to the atmospheric pressure (the negative pressure disappears).
Thus, it is possible to determine whether or not the atmospheric pressure in the ink suction device 11 is substantially equal to the atmospheric pressure by determining whether or not the atmospheric pressure in the ink suction device 11 has become substantially constant.

When the negative pressure sensor 14 confirms the disappearance of the negative pressure, the control device 100 acquires the negative pressure disappearance time using the clock 14.
The control device 100 can measure the negative pressure disappearance time from the time when the negative pressure sensor 13 starts measuring the atmospheric pressure in the ink suction device 11 and the negative pressure disappearance time.

Further, as shown in FIG. 6, viscosity determination information 47 is stored in the information file 43.
The viscosity determination information 47 is an example of negative pressure disappearance time viscosity information indicating the relationship between the ink viscosity and the negative pressure disappearance time, and is information for the control device 100 to determine the ink viscosity. That is, the control device 100 is also an example of a viscosity determination unit.

FIG. 7A is a diagram illustrating an example of the viscosity determination information 47.
As shown in FIG. 7A, the viscosity determination information 47 is, for example, data indicating the negative pressure extinction time measured on the horizontal axis and the viscosity (millipascal second (mPa · s)) on the vertical axis.

As shown in FIG. 7A, the viscosity determination information 47 includes, for example, CL1a that sucks 0.2 gram (g) of ink according to the negative pressure disappearance time setting cleaning mode, 0.5 gram (g). ) CL2a for sucking ink and CL3a for sucking 0.8 gram (g) of ink.
Based on the viscosity determination information 47, for example, when the ink suction device 11 in FIG. 6 performs ink suction in the CL2a mode, the control device 100 determines that the ink pressure is 10 seconds (s). It can be determined that the viscosity is 6 millipascal second (mPa · s).

Thus, according to the present embodiment, the viscosity of ink can be determined by measuring the negative pressure extinction time.
For this reason, since the recording head 30 liquid ejecting head of FIG. 4 does not have a configuration for determining the viscosity of the ink, no special configuration is required for the recording head 30. Therefore, the configuration is simple.
In addition, the viscosity of the ink can be determined based on the relationship with the negative pressure disappearance time, not based on the electrical resistance of the ink. This means that the viscosity can be determined regardless of the ink components and the like, so that the accurate viscosity of the ink can be determined.
As a result, the ink jet recording apparatus 10 can accurately measure the viscosity of the liquid while having a simple configuration.

  Further, as shown in FIG. 6, viscosity negative pressure release time information 48 is stored in the information file 43. The viscosity negative pressure release time information 48 indicates the negative pressure release time and the ink viscosity from when the ink suction device 11 stops sucking ink until the ink suction device 11 releases contact with the nozzle plate surface 61 of FIG. It is an example of the viscosity negative pressure release time information which shows a relationship.

FIG. 7B is an example of the viscosity negative pressure release time information 48.
As shown in FIG. 7B, the viscosity negative pressure release time information 48 includes, for example, a viscosity measured based on the above-described viscosity determination information 47 on the horizontal axis and an appropriate negative for the viscosity during normal cleaning on the vertical axis. This is information indicating the pressure release time.

The control device 100 of FIG. 6 can set the negative pressure release time for the next and subsequent cleanings based on the ink viscosity and the viscosity negative pressure release time information 48. That is, the control device 100 is also an example of a negative pressure release time setting unit that sets a negative pressure release time.
As shown in FIG. 5B, the viscosity negative pressure release time information 48 is, for example, CL1b for sucking 0.2 gram (g) of ink according to the normal cleaning mode, 0.5 gram (g), for example. Three types of data are included: CL2b for sucking the ink of CL3b and CL3b for sucking the ink of 0.8 gram (g).

  Based on the ink viscosity and viscosity negative pressure release time information 48, for example, if the ink viscosity is 6 millipascal second (mPa · s), the control device 100 determines that the negative pressure release time in the CL2b mode is 12 seconds. It is determined that it is sufficient to set (s), and the negative pressure release time is set to 12 seconds (s).

The negative pressure release time requires a long time if the viscosity of the ink is large, and a short time is sufficient if the viscosity of the ink is small. That is, the appropriate negative pressure release time varies depending on the viscosity of the ink.
In this respect, according to the configuration of the present embodiment, as described above, the viscosity of the ink can be accurately measured, so that an appropriate negative pressure release time can also be set accurately.

Next, an embodiment of a cleaning method in the ink jet recording apparatus 10 of FIG. 1 which is a preferred embodiment of the liquid ejecting apparatus of the present invention will be described mainly with reference to FIG.
FIG. 8 is a diagram illustrating an operation example of the ink jet recording apparatus 10.
The following description is based on the assumption that the negative pressure time setting cleaning mode is CL2a (see FIG. 7A).

When the inkjet recording apparatus 10 is activated and a cleaning instruction is given by a signal from the host computer 40 in FIG. 6, the control apparatus 100 in FIG. 6 controls the ink suction apparatus 11 to the suction state in FIG. Then, based on the negative pressure release time setting cleaning judgment information 45, it is determined whether the negative pressure release time setting cleaning or other normal cleaning is performed (step ST1).
If it is normal cleaning, the control device 100 executes a normal cleaning sequence (step ST21).

  In the case of the negative pressure release time setting cleaning, the ink suction device 11 performs step ST2, which is an example of a liquid suction step that contacts the nozzle plate surface 61 of FIG. To do. For example, after 5 seconds, ink suction is stopped (step ST3).

Subsequently, the control device 100 having the negative pressure extinction time measurement control information 46 of FIG. 4 as an example of the negative pressure extinction time measurement means stops the ink suction (step ST3) and then the ink. Steps ST4 to ST6, which are examples of a negative pressure extinction time measuring step for measuring the negative pressure extinction time until the atmospheric pressure of the suction device 11 becomes substantially equal to the atmospheric pressure, are executed.
In step ST4, the control device 100 starts measuring the atmospheric pressure with the negative pressure sensor of FIG. 4 based on the negative pressure disappearance time measurement control information 46, and simultaneously starts measuring the negative pressure disappearance time with the clock 14.

Then, the control device 100 determines whether or not the atmospheric pressure in the ink suction device 11 has become substantially constant (step ST5). In the process in which the negative pressure in the ink suction device 11 disappears, the atmospheric pressure in the ink suction device 11 fluctuates, but when the negative pressure in the ink suction device disappears and becomes substantially equal to the atmospheric pressure, The atmospheric pressure is constant. That is, the disappearance of the negative pressure in the ink suction device 11 is detected by detecting that the atmospheric pressure in the ink suction device 11 becomes constant.
When the atmospheric pressure in the ink suction device 11 becomes constant, the control device 100 in FIG. 6 ends the measurement of the negative pressure sensor 14 and at the same time ends the measurement of the negative pressure disappearance time (step ST6).

Subsequently, the control device 100 executes Step ST7 which is an example of a viscosity determination step for determining the viscosity of the ink based on the negative pressure disappearance time viscosity information indicating the relationship between the ink viscosity and the negative pressure disappearance time.
Specifically, if the negative pressure disappearance time measured in step ST6 described above is, for example, 6 seconds (s), the control device 100 determines a negative value based on, for example, the viscosity determination information 47 illustrated in FIG. Since it is the pressure time setting cleaning mode CL2a, it is determined that the viscosity of the ink is 6 millipascal second (mPa · s).

Subsequently, the control device 100 determines the negative pressure release time and the ink viscosity from when the ink suction device 11 stops sucking ink until the contact with the nozzle plate surface 61 (see FIG. 3) of the ink suction device 11 is released. Step ST8, which is an example of a negative pressure release time setting step for setting the negative pressure release time, is executed based on the viscosity negative pressure release time information indicating the relationship.
Specifically, if the viscosity of the ink determined in step ST6 is, for example, 6 millipascal second (mP · s), the control device 100 cancels the negative viscosity pressure shown in FIG. 7B, for example. Based on the time information 48, in the normal cleaning mode CL2b, it is determined that the negative pressure release time is 12 seconds (s) (step ST8), and the negative pressure release time is set to 12 seconds (s) (step ST9). ).

  As described above, according to the present embodiment, the viscosity of the ink can be accurately measured based on the negative pressure extinction time, and therefore an appropriate negative pressure release time can be set accurately. it can.

  The present invention is not limited to the above embodiment as an ink jet recording apparatus, and various modifications can be made without departing from the scope of the claims. Furthermore, the above-described embodiments may be combined with each other. Further, the present invention is not limited to an ink jet recording apparatus, but a recording head used in an image recording apparatus such as a printer, a color material ejection head used in manufacturing a color filter such as a liquid crystal display, an organic EL display, and an FED (surface emitting). Electrode material ejecting heads used for electrode formation such as displays), liquid ejecting apparatuses using liquid ejecting heads for ejecting liquids such as bioorganic ejecting heads used for biochip manufacturing, sample ejecting apparatuses as precision pipettes, etc. Applicable.

1 is a diagram illustrating an ink jet recording apparatus that is a preferred embodiment of a liquid ejecting apparatus of the invention. FIG. FIG. 3 is a diagram illustrating a structure example of a recording head. FIG. 3 is a diagram illustrating a structure example of a recording head. FIG. 4 is a diagram illustrating a shape example of a nozzle plate surface of a recording head. FIG. 3 is a diagram illustrating an example of the internal structure of a recording head. FIG. 3 is a diagram illustrating an example of electrical connection of an ink jet recording apparatus. The figure which shows an example of viscosity negative pressure extinction time information. FIG. 6 is a diagram illustrating an operation example of an ink jet recording apparatus.

Explanation of symbols

9A, 9B, 9C, 9D ... ink cartridge (an example of a liquid storage unit), 10 ... an ink jet recording apparatus (an example of a liquid ejecting apparatus), 11 ... an ink suction apparatus (an example of a suction apparatus), 12 ... Suction pump, 13 ... Negative pressure sensor, 20A, 20B, 20C, 20D ... Tube (an example of a liquid supply member), 30 ... Recording head (an example of a liquid jet head), 45. .. Cleaning judgment information for negative pressure time setting, 46... Negative pressure extinction time measurement control information, 47... Viscosity judgment information, 48... Viscosity negative pressure release time information, 100.

Claims (5)

A liquid ejecting head having a nozzle surface for ejecting liquid;
Suction means for sucking the liquid by negative pressure from the liquid jet head in contact with the nozzle surface;
Atmospheric pressure measuring means for measuring the atmospheric pressure in the suction means;
A negative pressure extinction time measuring means for measuring a negative pressure extinction time from when the suction means stops sucking the liquid until the atmospheric pressure in the suction means becomes substantially equal to atmospheric pressure;
Viscosity judging means for judging the viscosity of the liquid based on the viscosity information of the negative pressure extinction time indicating the relationship between the viscosity of the liquid and the negative pressure extinction time;
Based on the negative viscosity release time information indicating the relationship between the negative pressure release time from when the suction means stops sucking the liquid and releasing the contact of the suction means to the nozzle surface and the viscosity, the negative pressure is released. Negative pressure release time setting means for setting the pressure release time;
A liquid ejecting apparatus comprising:   The liquid ejecting apparatus according to claim 1, wherein the negative pressure extinction time measuring unit determines whether or not the atmospheric pressure in the suction unit becomes substantially constant.   The said atmospheric pressure measurement means is arrange | positioned in the said suction means in the nozzle surface vicinity position used as the vicinity of the said nozzle surface when the said suction means contacts the said nozzle surface. The liquid ejecting apparatus according to any one of 2. A liquid suction step in which the suction means of the liquid ejecting apparatus contacts the nozzle surface of the liquid ejecting head that ejects liquid and sucks the liquid from the liquid ejecting head by negative pressure; and
The negative pressure extinction time measuring means of the liquid ejecting apparatus measures the negative pressure extinction time from when the suction means stops sucking the liquid until the atmospheric pressure in the suction means becomes substantially equal to the atmospheric pressure. Annihilation time measurement step;
A viscosity determining step in which the viscosity determining means of the liquid ejecting apparatus determines the viscosity of the liquid based on negative pressure extinction time viscosity information indicating a relationship between the viscosity of the liquid and the negative pressure extinction time;
The negative pressure release time setting means of the liquid ejecting apparatus has a relationship between the negative pressure release time and the viscosity from when the suction means stops sucking the liquid until the suction means releases the contact with the nozzle surface. A negative pressure release time setting step for setting the negative pressure release time based on the viscosity negative pressure release time information shown;
A cleaning method for a liquid ejecting apparatus, comprising:   5. The liquid ejecting apparatus according to claim 4, wherein, in the negative pressure extinction time measuring step, the negative pressure extinction time measuring means determines whether or not the air pressure in the suction means has become substantially constant. Cleaning method.

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