JP2007118208A - Liquid ejector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid ejector in which very small liquid leakage is detected quickly. <P>SOLUTION: The liquid ejector 10 comprises: a liquid ejection head 30; a liquid storage means 45; a pressurization pump 40 generating pressurized air for supplying liquid in the liquid storage means 45 to the liquid ejection head 30 through a liquid passage 37; and a means 41 for measuring the pressure value of pressurized air. The ejector 10 is further provided with: information 104 indicative of the lowering range of air pressure corresponding to liquid leakage when liquid leakage is occurring in the liquid ejector 10; and a means 7 for judging whether liquid leakage is occurring when the pressurization pump 40 is stopped after an air pressure for detecting liquid leakage set within a range higher than an air pressure for printing is generated from the pressurization pump 40 based on the fact whether lowering of air pressure falls within the range corresponding to liquid leakage. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid ejecting apparatus that ejects liquid.

Conventionally, for example, various types of printers that eject ink have been developed as liquid ejecting apparatuses that include a liquid ejecting head (also referred to as a recording head) that ejects liquid contained in a detachable liquid cartridge.
Among such printers, for example, office and business models consume a large amount of ink as the printing frequency increases, so it is necessary to mount a large capacity ink cartridge. However, with a model (on-carriage type) in which a cartridge holder that accommodates an ink cartridge is placed on the carriage, simply placing a large-capacity ink cartridge increases the size of the carriage, and a large load is required to move the carriage. . For this reason, an off-carriage printer having a carriage and an ink cartridge separately has been developed.

In such an off-carriage printer, it is necessary to send ink in the ink cartridge to the carriage side. For this reason, a pressure pump is mounted on the printer, and the ink pack in the cartridge is crushed by sending the pressurized air from the pressure pump to the space in the ink cartridge, thereby pushing the ink to the carriage side.
Then, it is necessary to supply an appropriate amount of ink to the carriage side by maintaining the air pressure applied to the ink cartridge (main tank) within a predetermined range.

On the other hand, a photo sensor is arranged in a pressure detector that detects the pressure of the pressurizing pump, and the output when the movable member movable by the air pressure blocks the optical axis and the movable member deviates from the optical axis. There has been proposed a technique for maintaining the pressure of pressurized air within a predetermined range by using an output for controlling a pressurizing pump (for example, Patent Document 1).
JP 2001-199079 (FIG. 3 etc.)

  However, although the above-described technique can maintain the pressure of the pressurized air within a predetermined range for supplying an appropriate amount of ink, if there is an ink leak in the path from the ink pack to the recording head, the carriage side is moved to the carriage side. There is a problem that an appropriate amount of ink may not be supplied. In addition, there is a problem in that the ink in the ink pack may be wasted if the pressure of the pressurized air is maintained within the above-described predetermined range even though there is ink leakage in the path from the ink pack to the recording head. is there.

  Therefore, an object of the present invention is to provide a liquid ejecting apparatus that can solve the above-described problems and can quickly detect a minute liquid leak.

  In the present invention, the object is to provide a liquid ejecting head for ejecting liquid, liquid storing means for storing the liquid, and supplying the liquid in the liquid storing means to the liquid ejecting head via a liquid path. And a pressure measuring means for measuring an air pressure value of the pressurized air, wherein the liquid leakage occurs in the liquid ejecting apparatus. Liquid leak response reduction range information indicating a liquid leak response reduction range, which is a reduction range of the air pressure value, and a liquid leak detection air pressure set in a range higher than the air pressure value for printing When the pressurization pump is stopped after being generated by the pressurization pump, whether or not the decrease in the air pressure value is within the liquid leak response decrease range A liquid leakage determination means Les determines whether has occurred, by a liquid-jet apparatus characterized by having, is achieved.

According to such a configuration, the liquid leak detection air pressure set in a range higher than the air pressure value for printing is generated, and the decrease in the pressurized air value is within the liquid leak corresponding reduction range. Whether or not the liquid leakage has occurred can be determined.
Here, the liquid leak response reduction range can actually cause the liquid leakage and can be accurately measured in advance. The pressure measuring means can measure the air pressure value indicating the pressure of the pressurized air as a numerical value, not a rough measurement of whether or not the air pressure is in a certain range. For this reason, according to the liquid ejecting apparatus, it is possible to detect minute liquid leakage.
Further, the liquid leak determining means generates a liquid leak detecting air pressure set in a range higher than the air pressure value for printing, and determines a decrease in the air pressure value. As the air pressure value is higher, the amount of liquid leaking is larger, so that liquid leakage can be detected quickly. For this reason, according to the liquid ejecting apparatus, it is possible to quickly determine liquid leakage.
As described above, according to the liquid ejecting apparatus, it is possible to quickly detect a minute liquid leak.

  In this case, it is desirable that the pressure measuring means includes a diaphragm that is elastically deformed by the pressure of the pressurized air, and a linear encoder that measures the deformation of the diaphragm numerically.

  According to such a configuration, the pressure of the pressurized air can be measured numerically through the deformation of the diaphragm.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a plan view showing a schematic configuration of an ink jet recording apparatus 10 (hereinafter referred to as a printer 10). The printer 10 is an example of a liquid ejecting apparatus.
As shown in FIG. 1, the printer 10 includes a carriage 23 and an ink cartridge 24. The ink cartridge 24 stores ink. Ink is an example of a liquid.
The printer 10 is an off-carriage printer in which the ink cartridge 24 is not mounted on the carriage 23.

The carriage 23 is attached to an endless timing belt 27 stretched by a driving pulley 25 and a driven pulley 26, and the timing belt 27 is driven by a carriage motor 28, so that the carriage 23 is guided by a guide shaft 29. It is designed to reciprocate in the scanning direction (the direction of arrow T in FIG. 1).
A recording head 30 having a plurality of nozzle holes and ejecting ink is attached to the lower surface of the carriage 23. The recording head 30 is an example of a liquid ejecting head.
On the lower end side of the printer 10, a paper feed motor (not shown) is mounted as a driving source for feeding print paper. A gear is fixed to the output shaft of the paper feed motor, and this gear is connected to a paper feed roller (not shown) and a paper discharge roller (not shown) via a gear train. It is possible to feed paper.

  An ink supply tube 37 is connected to the carriage 23. The ink supply tubes 37 are arranged in the number of ink colors (for example, black, yellow, magenta, and cyan). The ink supplied to the carriage 23 is supplied to the recording head 30. The ink supply tube 37 is an example of a liquid path.

A pressurizing unit 38 including a pressurizing pump 40 is mounted on the upper surface of the ink cartridge 24 at the end of the main body. The pressurizing unit 38 is a device that sends out pressurized air to the ink cartridge 24 through the air supply tube 39, and includes a pressurizing pump 40, a pressure sensor 41, and an air release means 42.
The pressure pump 40 generates pressurized air for supplying the ink in the ink cartridge 24 to the recording head 30 via the ink supply tube 37. The pressurizing pump 40 is an example of a pressurizing pump.
The pressure sensor 41 measures the air pressure value of the pressurized air generated by the pressure pump 40. That is, the pressure sensor 41 is an example of a pressure measuring unit.
The air supply tube 39 is branched into a plurality of, for example, four in the present embodiment, by the distributor 43 on the downstream side of the pressure sensor 41, and each branched tube is connected to each color of the ink cartridge 24.

FIG. 2 is a schematic view showing the ink cartridge 24.
As shown in FIG. 2, the ink cartridge 24 includes an ink pack 45 serving as a liquid storage portion in which ink is sealed, and an ink case 46 that stores the ink pack 45. The ink pack 45 is an example of a liquid storage unit that stores a liquid.
The ink pack 45 has an ink discharge port 45a, and an ink supply tube 37 is connected to the ink discharge port 45a. Only the ink discharge port 45a of the ink pack 45 is exposed to the outside, and the other portions are stored in the ink case 46 in an airtight state, whereby an airtight space 47 is formed inside the ink case 46.

The ink case 46 is formed with a communication hole (not shown) that communicates with the space 47, and the air supply tube 39 is connected to the communication hole so that the communication hole and the air supply tube 39 communicate with each other. It has become. When the pressurizing pump 40 is operated and the pressurized air is discharged, the pressurized air is introduced into the space 47 in the ink cartridge 24 through the air supply tube 39, and the ink pack 45 is caused to be blown by the air pressure of the pressurized air. It is crushed.
As a result, the ink in the ink pack 45 is supplied to the carriage 23 via the ink supply tube 37.
In this way, the pressure of the pressurized air rises as the exhaust / intake of the pressurizing pump 40 is repeated, and the ink pack 45 is crushed to supply ink to the carriage 23 side.
The printer 10 drives a carriage motor 28 and a paper feed motor based on print data fetched from a host computer or a memory card, and discharges ink from the recording head 30 to execute print processing.

FIG. 3 is a schematic diagram showing the connection of the pressurizing pump 40 and the like.
As shown in FIG. 3, a regulator 50 that adjusts the pulsation of air pressure is connected to the pressurizing pump 40. A pressure sensor 41 is connected to the regulator 50. The ink cartridge 24 is connected to the pressure sensor 41.

FIG. 4 is a schematic diagram showing the pressure sensor 41.
FIG. 4A is a schematic plan view of the pressure sensor 41.
FIG. 4B is a schematic cross-sectional view taken along line AA of the pressure sensor 41 in FIG.
As shown in FIG. 4B, the pressure sensor 41 has a diaphragm storage 66 that stores the diaphragm 68. The diaphragm 68 is elastically deformed by the pressure of pressurized air supplied from the regulator 50 via the inlet 64. This diaphragm 68 is an example of a diaphragm. The diaphragm 68 is made of, for example, nitrile rubber.
The diaphragm 68 is connected to the linear scale holding unit 76. For this reason, the linear scale holding part 76 moves in the arrow U direction by the deformation of the diaphragm 68. Then, the linear scale 74 fixed to the linear scale holding unit 76 moves in the arrow U direction as the linear scale holding unit 76 moves. The movement of the linear scale 74 is measured as a numerical value by the encoder 70 held by the encoder holding unit 72. The encoder holding unit 72 is fixed to the diaphragm storage unit 66.
Since the pressure sensor 41 is configured as described above, the deformation of the diaphragm 66 can be measured numerically by the linear scale 74 and the encoder 70.
The linear scale 74 and the encoder 70 described above are an example of a linear encoder.
The pressurized air in the pressure sensor 41 is sent to the ink cartridge 24 through the outlet 66.
According to such a configuration, the pressure of the pressurized air can be measured numerically through the deformation of the diaphragm 68.

FIG. 5 is a schematic diagram illustrating an example of electrical connection of the printer 10.
As shown in FIG. 5, the printer 10 includes a control device 7, and the control device 7 receives a signal related to control from the printer driver 202 of the host computer 200. On the other hand, the control device 7 transmits various information to the host computer 200.
As shown in FIG. 5, the control device 7 is connected to the ink cartridge 24, the recording head 30, the carriage 23, the pressure pump 40, and the pressure sensor 41.

As illustrated in FIG. 5, the control device 7 includes a first storage unit 100 that stores various types of information and a second storage unit 150 that stores various types of programs.
The first storage unit 100 stores driving pressure range information 102. The driving pressure range information 102 is information indicating the range of the air pressure value of the pressurized air in the pressure sensor 41 required during printing by the printer 10.

FIG. 6 is a diagram illustrating an example of a change in the air pressure value of the pressurized air in the pressure sensor 41.
When receiving a print start command at time t0, the control device 7 drives the pressurizing pump 40 to increase the air pressure value of the pressurized air as indicated by the straight line L1a.
When the air pressure value of the pressurized air reaches 14 kPa, which is the upper limit value of the driving pressure P1 indicated in the driving pressure range information 102 at time t1, the control device 7 stops driving the pressurizing pump 40.
When the control device 7 starts printing from time t1, the volume of the ink pack 45 (see FIG. 2) decreases as the ink is consumed, so that the air pressure value of the pressurized air gradually decreases as shown by the straight line L1b. To do.
When the air pressure value of the pressurized air reaches 8 kPa, which is the lower limit value of the driving pressure P1 indicated in the driving pressure range information 102 at time t2, the control device 7 resumes driving of the pressurizing pump 40, As indicated by the straight line L1c, the air pressure value of the pressurized air is increased.
Then, when printing ends at time t3, the control device 7 stops driving the pressurizing pump 40. After the printing is finished, the air pressure of the pressurized air is caused by a natural leak due to gas permeation from the ink supply tube 37 (see FIG. 1) or a leak from a check valve (not shown) of the pressurizing pump 40. The value decreases as shown by the straight line L1d.

  As shown in FIG. 5, the printer 10 stores ink leakage corresponding pressure drop range information 104 in the first storage unit 100. The ink leak corresponding pressure decrease range information 104 indicates an ink leak corresponding decrease range that is a decrease range of the air pressure value of the pressurized air when ink leak (hereinafter referred to as ink leak) occurs in the printer 10. Information. The ink leak corresponding pressure decrease range is an example of a liquid leak corresponding decrease range, and the ink leak corresponding pressure decrease range information 104 is an example of liquid leak corresponding decrease range information.

The ink leakage corresponding pressure drop range information 104 is due to ink leakage at each joint portion (not shown) of the path from the ink pack 45 to the recording head 30 or a welding failure of the welding portion of the film constituting the outer wall of the ink pack 45. A decrease in air pressure value corresponding to ink leakage is shown.
As shown in FIG. 5, the pressure drop in the pressure range corresponding to ink leakage is, for example, 25 seconds (s) when the pressure pump 40 is stopped after the air pressure value of the pressurized air is increased to 40 kPa. Furthermore, the pressure drop is 0.1 kPa or more. Note that the air pressure value (for example, 40 kPa) of the pressurized air at the start of ink leakage detection is also referred to as applied pressure.

As shown in FIG. 6, the standard of the pressure drop amount due to the printing discharge is 1 second (s) when the pressure pump 40 is stopped after the air pressure value of the pressurized air is increased to 20 kPa. , 0.013 kPa. The standard of the pressure drop due to the natural leak due to gas permeation through the ink supply tube 37 is 1 second (s) when the pressure pump 40 is stopped after increasing the air pressure value of the pressurized air to 20 kPa. In addition, it is known to be 0.00746 kPa. Further, it is known that the standard of the pressure drop due to leakage from the check valve (not shown) of the pressurizing pump 40 is 0.005 kPa in 1 second (s).
The printer 10 does not detect the pressure drop or the like due to the above-described print discharge, but detects the air pressure value drop corresponding to the ink leakage.

As shown in FIG. 5, the printer 10 stores an ink leakage detection program 152 in the second storage unit 150. The ink leak detection program 152 indicates that when the control device 7 generates 40 kPa of pressurized air by the pressurization pump 40 and stops driving the pressurization pump 40, the decrease in the air pressure value corresponds to the ink leak described above. This is a program for determining whether or not ink leakage has occurred depending on whether or not the pressure falls within a range. In the ink leakage detection program 152, the air pressure value of the generated pressurized air is set in a range higher than the air pressure value for printing. The air pressure value of 40 kPa is an example of air pressure for detecting liquid leakage. The control device 7 having the ink leakage detection program 152 is an example of a liquid leakage determination unit.
When the control device 7 stops the driving of the pressurizing pump 40 after generating the pressurized air of 40 kPa, the ink is discharged when the air pressure value decreases by 0.1 kPa or more in 25 seconds (s). Judge that a leak has occurred.

  When determining that ink leakage has occurred, the control device 7 transmits a signal notifying ink leakage to the host computer 200. The host computer 200 can notify the user of the printer 10 that ink leakage has occurred by displaying a message notifying ink leakage on a display screen (not shown).

The printer 10 is configured as described above.
According to such a configuration, 40 kPa of pressurized air set in a range higher than the air pressure value for printing is generated, and the decrease in the air pressure value is within the ink leak corresponding pressure decrease range for 25 seconds. During (s), it can be determined whether or not ink leakage has occurred depending on whether or not the decrease is 0.1 kPa or more.
Here, the ink leak compatible pressure drop range can actually cause liquid leakage, and can be measured in advance precisely. The pressure sensor 41 can measure the air pressure numerically instead of a rough measurement of whether or not the pressure is in a certain range. For this reason, the printer 10 can detect minute ink leakage.
In addition, the printer 10 generates 40 kPa of pressurized air set in a range higher than the air pressure value for printing, and determines a decrease in the air pressure value. As the air pressure value is higher, the amount of ink leaking is larger, so that ink leakage can be detected quickly. Therefore, according to the printer 10, it is possible to quickly determine ink leakage.
As described above, according to the printer 10, a minute ink leak can be detected quickly.

  Hereinafter, main operation examples of the printer 10 will be described mainly with reference to FIG.

FIG. 7 is a schematic flowchart illustrating an operation example of the printer 10.
First, it is determined whether the printer 10 has received a print command (step ST1 in FIG. 7). When the printer 10 determines that it has received the print command, it drives the pressurizing pump 40 to increase the air pressure value of the pressurized air to 40 kPa, and then stops the pressurizing pump 40 (step ST2). The air pressure value is measured by the pressure sensor 41.

Subsequently, the printer 10 determines whether or not 25 seconds (s), which is an ink leakage detection time, has elapsed (step ST3).
When determining that the ink leakage detection time has elapsed, the printer 10 measures the air pressure value of the pressurized air (step ST4).
Subsequently, the printer 10 determines whether or not the pressure drop amount for 25 seconds is within the ink leak compatible pressure drop range (step ST5).

  When the printer 10 determines in step ST5 that the pressure drop amount for 25 seconds is within the ink leak corresponding pressure drop range, it transmits a signal indicating that there is ink leak to the host computer 200 (step ST6).

  On the other hand, if the printer 10 determines in step ST5 that the pressure drop amount for 25 seconds is not within the ink leak corresponding pressure drop range, it transmits a signal indicating that there is no ink leak to the host computer 200. (Step ST7).

  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 ejection heads used for electrode formation such as displays), liquid ejection devices using liquid ejection heads that eject liquids such as bio-organic matter ejection heads used in biochip manufacturing, sample ejection devices as precision pipettes, etc. Applicable.

  Moreover, each structure of the said embodiment can abbreviate | omit one part or can be arbitrarily combined so that it may differ from the above.

1 is a plan view showing a schematic configuration of an ink jet recording apparatus. It is a schematic sectional drawing of the ink cartridge of the printer of FIG. It is the schematic which shows an example of the mode of a connection, such as a pressure pump. It is the schematic which shows a pressure sensor. It is a figure which shows an example of the electrical connection of a printer. It is a figure which shows an example of the change of the air pressure value of the pressurized air in a pressure sensor. 3 is a schematic flowchart illustrating an operation example of a printer.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Printer, 23 ... Carriage, 24 ... Ink cartridge, 30 ... Recording head (liquid ejecting head), 40 ... Pressure pump, 41 ... Pressure sensor, 68 ... Diaphragm, 70 ... Encoder, 74 ... Linear scale

Claims (2)

A liquid ejecting head for ejecting liquid;
Liquid storage means for storing the liquid;
A pressure pump for generating pressurized air for supplying the liquid in the liquid storage means to the liquid jet head via a liquid path;
Pressure measuring means for measuring an air pressure value of the pressurized air;
A liquid ejecting apparatus comprising:
Liquid leak corresponding decrease range information indicating a liquid leak corresponding decrease range that is a decrease range of the air pressure value when the liquid leak occurs in the liquid ejecting apparatus;
When the pressurization pump is stopped after the air pressure for liquid leak detection set in a range higher than the air pressure value for printing is generated by the pressurization pump, the decrease in the air pressure value is: A liquid leakage determination means for determining whether or not the liquid leakage has occurred, depending on whether or not the liquid leakage response reduction range is within;
A liquid ejecting apparatus comprising: The pressure measuring means includes
A diaphragm that is elastically deformed by the pressure of the pressurized air;
A linear encoder for numerically measuring the deformation of the diaphragm;
The liquid ejecting apparatus according to claim 1, comprising:

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