JP2012162010A - Liquid ejecting apparatus, and flushing method therein - Google Patents

Abstract

Provided is a flushing method for an ink jet recording apparatus in which when a printing condition changes, a condition for periodic flushing can be changed accordingly.
A flushing method in a liquid ejecting apparatus includes: a transport unit that transports a medium; a liquid ejecting head that ejects liquid; and a control unit that performs a flushing operation to eject liquid other than the medium at a predetermined interval. A comparison process for comparing the flushing condition at the previous ejection job and the flushing condition at the current ejection job when transporting the first medium based on the ejection job data, and based on the result of the comparison process Thus, it is characterized in that whether to perform the flushing execution process for executing the flushing or not to perform the flushing is selected.
[Selection] Figure 4

Description

  The present invention relates to a liquid ejecting apparatus that ejects liquid and a flushing 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 on a recording medium by ejecting minute ink droplets from the nozzles of the recording head onto the recording medium.
However, nozzles that are used less frequently among the nozzles of the recording head may not discharge ink droplets properly during image recording due to an increase in the viscosity of the ink, which may cause a discharge failure. As a result, a portion (hereinafter referred to as “dot missing”) where an image cannot be recorded correctly occurs on the recording medium.
In order to cope with such a problem, a method is known in which periodic flushing is performed to periodically eject ink from the nozzle outside the image recording area, and the nozzle is filled with new ink. For example, as shown in Patent Document 1 below, defective discharge is prevented by determining the interval of periodic flushing based on the average number of defective discharges indicating the number of targets ejected with liquid corresponding to one cleaning cycle. ing.

JP 2006-95816 A

However, when performing regular flushing based on the average number of defective ejections, for example, it is effective when printing 150 sheets under the same conditions, but in the case of printing where the printing conditions change each time, the average ejection defects are effective. Even when the number of sheets has not been reached, the print quality may require periodic flushing. On the other hand, depending on the printing conditions, even if the average number of defective ejections is exceeded, the printing quality that does not require periodic flushing may be maintained.
Accordingly, the present invention has been made in view of the above-described problems, and an object thereof is to provide a liquid ejecting apparatus that efficiently performs periodic flushing.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
The flushing method in the liquid ejecting apparatus according to this application example includes a transport unit that transports a medium, a liquid ejecting head that ejects liquid, and a control unit that performs a flushing operation for ejecting the liquid other than the medium at a predetermined interval. A flushing method in a liquid ejecting apparatus comprising: comparing a flushing condition during a previous ejection job with a flushing condition during a current ejection job when transporting the first medium based on ejection job data And a flushing execution step for performing flushing, and whether or not to execute the flushing execution step is selected based on a result of the comparison step.

  According to the present invention, when the first medium is transported based on the ejection job data in the liquid ejecting apparatus, the flushing condition of the previous ejection job is compared with the flushing condition of the current ejection job, and the flushing is performed based on the comparison result. Whether or not to execute is determined. Accordingly, whether or not flushing can be performed is determined based on the flushing condition according to the ejection job, and thus unnecessary flushing can be suppressed and the flushing can be efficiently performed in the liquid ejecting apparatus.

[Application Example 2]
In the flushing method in the liquid ejecting apparatus according to the application example described above, whether the result of the comparison step is the same as the flushing condition in the previous ejection job and the flushing condition in the current ejection job. If the comparison results are the same, flushing is not performed.

  If the flushing conditions in the previous ejection job and the current ejection job are the same, the liquid in the head is flushed at regular intervals when ejecting to the medium, even if flushing is not performed during medium transport. Can suppress the increase in viscosity. Accordingly, it is possible to prevent unnecessary flushing by executing flushing during medium conveyance.

[Application Example 3]
In the flushing method in the liquid ejecting apparatus according to the application example, the flushing condition includes at least one of a flushing interval, a flushing discharge amount, a medium type, a liquid ejecting mode, and a flushing weighting.

  Since we are only comparing whether or not the flushing conditions for the previous jetting job and the flushing conditions for the current jetting job are the same, not only the flushing interval and flushing discharge amount, but also the type of medium and liquid It becomes possible to use the injection mode, weighting of flushing, etc., and the choice of data to be used increases.

[Application Example 4]
In the flushing method in the liquid ejecting apparatus according to the application example, the comparison step includes a step of comparing the flushing interval or the flushing discharge amount. As a result of the comparison, the current flushing interval or the flushing discharge amount is small. If the flushing condition is the same, the flushing condition is not executed if the flushing condition for the previous ejection job and the flushing condition for the current ejection job are the same.

  If the current job has a smaller flushing interval or flushing discharge amount than the previous job, it may already be in the flushing condition, so executing the flushing will suppress the thickening of the liquid in the head. To do.

[Application Example 5]
In the flushing method in the liquid ejecting apparatus according to the application example described above, if the result of comparing the flushing interval or the flushing discharge amount in the comparison step is large, a timer for measuring the flushing interval has already elapsed. It is characterized by being set and started taking into account the current time.

  If the current job has a larger flushing interval or flushing discharge amount than the previous job, starting the timer at a new flushing interval will result in a longer interval that has already elapsed. By starting taking into account the time that has already passed, flushing can be performed at appropriate time intervals.

[Application Example 6]
The liquid ejecting apparatus according to this application example includes: a transport unit that transports a medium; a liquid ejecting head that ejects liquid; and a control unit that performs a flushing operation to eject the liquid other than the medium at a predetermined interval. The liquid ejecting apparatus includes a flushing condition for the previous ejection job and a flushing condition for the current ejection job, when the control unit transports the first medium based on ejection job data. Then, based on the comparison result, whether or not to perform flushing is selected.

  According to the present invention, when the first medium is transported based on the ejection job data, the flushing condition of the previous ejection job is compared with the flushing condition of the current ejection job, and the flushing is executed based on the comparison result. No is determined. Accordingly, whether or not flushing can be performed is determined based on the flushing condition according to the ejection job, and thus unnecessary flushing can be suppressed and the flushing can be efficiently performed in the liquid ejecting apparatus.

1 is a diagram illustrating an overall configuration of an ink jet recording apparatus. FIG. 2 is a block diagram illustrating a functional configuration of the ink jet recording apparatus. 3 is a flowchart showing a processing flow of the ink jet recording apparatus. 6 is a flowchart showing a flow of processing during a paper feeding operation. The figure which shows the relationship between printing quality and regular flushing condition priority. The figure which shows the relationship between a regular flushing condition priority and a regular flushing condition.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

(Embodiment)
FIG. 1 is a schematic view showing an ink jet recording apparatus 10 which is an embodiment of a liquid ejecting apparatus of the present invention.
The ink jet recording apparatus 10 is a so-called ink jet printer, and is an apparatus for recording an image or the like on a sheet 29 which is an example of a target. The main body 1 of the ink jet recording apparatus 10 includes a guide rail 17, a platen 12, a carriage 14, an ink suction device 20, and a recording head 30. The recording head 30 is an example of a liquid ejecting head that ejects ink, which is an example of liquid, onto the paper 29, and is also called a print head. Although not shown, the main body 1 includes a transport unit that transports the paper 29 to a predetermined position.

  The ink jet recording apparatus 10 of the present embodiment is a so-called on-carriage recording apparatus, and a plurality of ink cartridges 2, 3, 4 and 5 are detachably mounted on the top of the carriage. These ink cartridges 2, 3, 4 and 5 are filled with ink. A recording head 30 is provided below the carriage 14. A nozzle plate surface 30 a that the recording head 30 faces the paper 29 is provided with nozzle openings (not shown) for ejecting ink (hereinafter also referred to as ejection).

  The carriage 14 is connected to a motor 16 via a belt 15. As the motor 16 rotates, the carriage 14 reciprocates along the guide rail 17 in the main scanning direction T that is the axial direction of the platen 12. At that time, the carriage 14 reciprocates in the main scanning direction T while ejecting ink from the recording head 30, whereby an image is recorded on the sheet 29 conveyed by the conveying unit.

  A home position 18 is located at one end of the guide rail 17. The home position 18 is a non-image recording area at the end of the carriage travel path where the paper 29 is not located. An ink suction device 20 is disposed on the main body 1 at the home position 18. This ink suction device 20 is also called a capping system or capping means. The recording head 30 disposed on the carriage 14 in FIG. 1 faces the cap body 21 of the ink suction device 20 by moving to the home position 18 along the T1 direction. The cap body 21 is in close contact with the nozzle plate surface 30 a of the recording head 30.

The ink suction device 20 has a function of preventing ink from drying at the nozzle openings of the recording head 30 while being in close contact with the recording head 30, and a negative pressure from the suction pump 19 is applied to the nozzle openings to cause ink to be discharged from the nozzle openings. It has a function to forcibly suck and discharge. In other words, the ink suction device 20 performs cleaning to recover ejection failure that is a state in which ink is not ejected normally from the recording head 30 by sucking ink from the nozzle openings of the recording head 30.
The suction pump 19 is one of the components constituting the ink suction device 20. A wiping member 23 is provided beside the ink suction device 20. The wiping member 23 wipes ink on the nozzle plate surface 30a of the recording head 30 as necessary.
Unlike the present embodiment, when cleaning, the ink may be ejected from the recording head 30 instead of the operation of sucking the ink from the recording head 30 by the negative pressure from the suction pump 19.

A flushing position 32 is located at the other end of the guide rail 17 opposite to the home position 18. This flushing position 32 is also a non-image recording area.
The recording head 30 performs regular flushing in which ink is periodically ejected from the nozzle openings during the printing operation at the flushing position 32 or the home position 18 described above. Periodic flushing maintains the ink ejection state from the nozzle openings.

  As shown in FIG. 1, an ejection failure detection device 8 is disposed on the carriage 14. The ejection failure detection device 8 is an example of ejection failure detection means that detects ejection failure in which ink is not ejected normally from the recording head 30.

  In the present embodiment, the plurality of ink cartridges 2, 3, 4, and 5 are directly mounted on the carriage 14. However, the present invention is not limited to this, and the ink cartridges 2, 3, 4, and 5 are different from the carriage 14. A so-called off-carriage type ink jet recording apparatus 10 mounted at another position may be employed.

FIG. 2 is a block diagram showing a functional configuration of the ink jet recording apparatus 10. The ink jet recording apparatus 10 includes a control device 7, an ejection failure detection device 8, an ink suction device 20, ink cartridges 2, 3, 4 and 5, a recording head 30 and a carriage drive device 25.
The control device 7 includes a storage unit 72 that stores various types of information, a calculation unit 74 that performs various types of calculations, and a CL control unit 76 that controls cleaning, and functions to control each function of the inkjet recording apparatus 10 as a control unit. Have. The control device 7 is connected to a printer driver 81 of the host computer 80 via a printer cable or a communication network. The printer driver 81 includes software for sending a command for causing the ink jet recording apparatus 10 to execute printing, cleaning operation, or ink suction operation. The control device 7 is stored in hardware such as a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory) and a flash memory, and a ROM and a flash memory, all of which are not shown. Each function is realized through collaboration with the software.

The storage unit 72 records the number of cleanings described above by the ink suction device 20 or the like. The number of cleanings referred to here excludes cleaning that is automatically performed after a certain period of time has passed, and cleaning that is automatically performed when the ink cartridges 2, 3, 4, and 5 are replaced. This means manual cleaning performed by the user of the recording apparatus 10.
Note that, unlike the present embodiment, the number of detected dot omissions may be used instead of the number of cleanings.

  In addition, the storage unit 72 stores the number of sheets 29 on which ink is ejected and the conditions for periodic flushing (periodic flushing conditions). In the present embodiment, the flushing interval, flushing discharge amount, medium type, liquid ejection mode, flushing weighting, and the like are assumed as the regular flushing conditions.

FIG. 3 is a flowchart showing a processing flow when the ink jet recording apparatus 10 in the standby state receives a job and prints it.
When the process is started, the control device 7 performs initial setting and prepares to use the ink jet recording apparatus 10 (step S11).
Next, the control device 7 acquires one job to be printed (step S12), and acquires the print quality and print data of the acquired job.
Subsequently, the control device 7 performs a paper feeding operation (step S13). Details of step S13 will be described later.
Next, the control device 7 performs printing on the paper 29 (step S14), and determines whether or not there is a next page in the job (step S15).

Here, if it is determined that there is a next page in the job (YES in step S15), the process returns to step S13, and the processes in and after step S13 are repeated.
On the other hand, if it is determined that there is no next page in the job (NO in step S15), the control device 7 determines whether there is a next job to be printed (step S16).
Here, if it is determined that there is a job to be printed next (YES in step S16), the process returns to step S12, and the processes after step S12 are repeated.
On the other hand, if it is determined that there is no next job to be printed (NO in step S16), the series of processes is terminated, and the inkjet recording apparatus 10 transitions to a standby state.

  FIG. 4 is a flowchart showing details of the processing flow of step S13, and shows a control form performed in the operation of feeding the paper 29. The purpose of this operation is to set the regular flushing condition priority in accordance with the unit number of the job at that time, and to perform flushing if necessary. The print quality, the regular flushing condition priority order, and the regular flushing condition are linked based on the information shown in FIGS. In the present embodiment, the information shown in FIGS. 5 and 6 is stored in the storage unit 72.

  FIG. 5 shows information for associating the unit number, the print quality, and the regular flushing condition priority order, and is stored in the storage unit 72. Based on this information, the regular flushing condition priority order can be determined from the unit number included in the print job data.

  FIG. 6 is a table for associating the regular flushing condition priority, the flushing seg number, and the regular flushing interval time, and is stored in the storage unit 72. Based on this information, the flushing seg number and the regular flushing interval time can be determined from the regular flushing condition priority. Note that seg is a unit of ink ejection processing, and in this embodiment, 1 seg is set so that about 2.5 nanograms (ng) of ink is ejected in one shot or two shots. .

Returning to FIG. 4, when this process is started, the control device 7 determines whether or not the predetermined flag included in the job is “0” (step S21).
Here, if the predetermined flag is not “0” (NO in step S21), the series of processes is terminated. On the other hand, if the predetermined flag is “0” (YES in step S21), the value of the predetermined flag is set to “1” (step S22), and step S23 and subsequent steps are executed.
In the present embodiment, as shown in step S21 and step S22, nothing is performed except the first printing in the job. Although not shown, since the predetermined flag returns to “0” when the job is completed, the feeding operation is executed at the first printing of the next job. That is, since the print quality is set for each job, there is no need to reset the regular flushing condition priority order or perform flushing other than the regular flushing within the same job.

In step S23, the control device 7 sets the regular flushing condition priority order according to the unit number (print quality) of the job based on the information in FIG. The set regular flushing condition priority order is stored in the storage unit 72.
Subsequently, the control device 7 acquires the previous regular flushing interval time from the previous regular flushing condition priority order based on the information of FIG. 6 (step S24). The previous regular flushing condition priority order is the regular flushing condition priority order set for the job if a job exists immediately before. When the current job is the first time, the priority “5” corresponding to the state where the unit number is indefinite is set in the previous regular flushing condition priority.

Subsequently, the control device 7 acquires the regular flushing interval time from the regular flushing condition priority order based on the information of FIG. 6 (step S25).
Subsequently, the control device 7 enters a comparison process, and compares the regular flushing condition priority with the previous regular flushing condition priority (step S26). As a result of the comparison, if the two orders are the same (NO in step S26), the series of processes is terminated.
On the other hand, if the two orders are different (YES in step S26), the control device 7 compares the regular flushing interval time with the previous regular flushing interval time (step S27).

As a result of the comparison, if the regular flushing interval time is equal to or longer than the previous regular flushing interval time (NO in step S27), the control device 7 sets the regular flushing timer and starts the timer (step S34), and proceeds to step S33. In the present embodiment, the regular flushing timer T1 set in the timer is calculated by the following equation, taking into account the time that has already elapsed.
T1 = periodic flushing interval time− (previous regular flushing interval time−periodic flushing timer value) (Equation 1)
On the other hand, when the regular flushing interval time is smaller than the previous regular flushing interval time (YES in step S27), the control device 7 compares the regular flushing condition priority with the previous regular flushing condition priority (step S28). .

As a result of comparison, if the regular flushing condition priority is lower than the previous regular flushing condition priority (YES in step S28), the control device 7 determines the number of flushing seg according to the regular flushing condition priority based on the information of FIG. Is set (step S29), and the process proceeds to step S31.
On the other hand, when the regular flushing condition priority is equal to or higher than the previous regular flushing condition priority (NO in step S28), the control device 7 performs the flushing seg number corresponding to the previous regular flushing condition priority based on the information in FIG. Is set (step S30), and the process proceeds to step S31.

In step S31, the control device 7 performs flushing for the number of flushing seg set in either step S29 or step S30 (flushing execution step).
Subsequently, the control device 7 resets the regular flushing interval time, sets the regular flushing timer to the regular flushing interval time, and starts a countdown (step S32). When the periodic flushing timer expires during printing, the control device 7 performs flushing for the number of flushing seg corresponding to the regular flushing condition priority order at that time.
Subsequently, the control device 7 substitutes the regular flushing condition priority order for the previous regular flushing condition priority order (step S33), and ends the series of processes.

  With the processing described above, the priority order of the regular flushing conditions is determined according to the unit number and print quality, and the regular flushing interval time is determined based on the determined regular flushing condition priority order and the number of flushing seg. Periodic flushing of the ink jet recording apparatus 10 can be efficiently performed according to print quality, unit number, and the like. Therefore, the throughput of the ink jet recording apparatus 10 can be improved.

  In the illustrated embodiment, four ink cartridges 2, 3, 4, and 5 that use black ink, cyan ink, magenta ink, and yellow ink can be mounted on the carriage. However, the present invention is not limited to this, and may be one that includes only an ink cartridge for black ink, or one that includes three ink cartridges for three-color printing excluding black ink. Further, it may be one in which five or more ink cartridges using ink can be mounted on the carriage.

The present invention is not limited to the above-described embodiment as the ink jet recording apparatus 10, and various modifications can be made without departing from the scope of the claims.
For example, the liquid ejecting apparatus of the present invention may be a liquid ejecting apparatus that ejects another liquid. The liquid ejecting apparatus of the present invention is used, for example, in liquid ejecting apparatuses that eject liquids such as electrode materials and color materials used in the manufacture of liquid crystal displays, EL (electroluminescence) displays, and surface emitting displays, and in biochip manufacturing. It may be a liquid ejecting apparatus that ejects biological organic matter, or a sample ejecting apparatus as a precision pipette.
A part of each configuration of the above embodiment may be omitted, and is not limited to the described combination, and can be arbitrarily combined.

  DESCRIPTION OF SYMBOLS 1 ... Main-body part, 2, 3, 4, 5 ... Ink cartridge, 7 ... Control apparatus, 8 ... Ejection defect detection apparatus, 10 ... Inkjet recording apparatus, 12 ... Platen, 14 ... Carriage, 15 ... Belt, 16 ... Motor , 17 ... guide rail, 18 ... home position, 19 ... suction pump, 20 ... ink suction device, 21 ... cap body, 23 ... wiping member, 25 ... carriage drive device, 29 ... paper, 30 ... recording head, 30a ... nozzle Plate surface, 32: Flushing position, 72: Storage unit, 74: Calculation unit, 76: CL control unit, 80: Host computer, 81: Printer driver.

Claims (6)

A flushing method in a liquid ejecting apparatus, comprising: a transport unit that transports a medium; a liquid ejecting head that ejects liquid; and a control unit that performs a flushing operation to eject the liquid in addition to the medium at a predetermined interval. ,
A comparison step of comparing the flushing condition at the previous ejection job with the flushing condition at the current ejection job when transporting the first medium based on the ejection job data;
A flushing execution step for performing flushing, and
A flushing method in a liquid ejecting apparatus, wherein whether or not to perform the flushing execution step is selected based on a result of the comparison step.   The result of the comparison step includes a step of comparing whether or not the flushing condition at the time of the previous jetting job and the flushing condition at the time of the current jetting job are the same, and the result of the comparison is the same The flushing method in the liquid ejecting apparatus according to claim 1, wherein the flushing is not executed.   The flushing method for a liquid ejecting apparatus according to claim 2, wherein the flushing condition includes at least one of a flushing interval, a flushing discharge amount, a medium type, a liquid ejecting mode, and a weighting for flushing.   The comparison step includes a step of comparing the flushing interval or the flushing discharge amount. If the comparison result indicates that the current flushing interval or the flushing discharge amount is small, the flushing is executed and the previous injection is performed. 4. The flushing method in the liquid ejecting apparatus according to claim 1, wherein the flushing is not executed when the flushing condition at the time of the job and the flushing condition at the time of the current ejection job are the same.   In the comparison step, as a result of comparing the flushing interval or the flushing discharge amount, if it is large, a timer for measuring the flushing interval is set and started taking into account the time that has already passed. The flushing method in the liquid ejecting apparatus according to claim 4. A liquid ejecting apparatus comprising: a conveying unit that conveys a medium; a liquid ejecting head that ejects a liquid; and a control unit that performs a flushing operation for ejecting the liquid in addition to the medium at a predetermined interval.
The control means compares the flushing condition at the previous ejection job with the flushing condition at the current ejection job when conveying the first medium based on the ejection job data, and based on the comparison result. A liquid ejecting apparatus that selects whether or not to perform flushing.

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