JP2003291370A - Liquid jet apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid jet apparatus which can carry out a cleaning operation having superior effects for recovering the liquid drop discharge capability without affecting the discharge of bubbles in a channel. <P>SOLUTION: The liquid jet apparatus has a head member which includes a plurality of nozzle openings, a plurality of pressure generation chambers which communicate with the nozzle openings respectively, a plurality of liquid supply paths for supplying a liquid to each pressure generation chamber, a liquid storage chamber with which each liquid supply path communicates in common, a liquid supply hole which communicates with the liquid storage chamber, and a plurality of pressure generation means for discharging liquid drops from nozzle openings by changing a pressure of the liquid in pressure generation chambers respectively. A cleaning means sucks the liquid from the plurality of nozzle openings in common. While the cleaning means drives, a cleaning auxiliary means drives pressure generation means corresponding to at least one group of nozzle openings on the basis of a cleaning control condition set for each group of nozzle openings grouped on the basis of a position relation to the liquid supply hole. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid ejecting apparatus having a head member for ejecting a liquid from a nozzle opening, for example, an ink jet recording apparatus having a recording head for ejecting ink droplets from the nozzle opening for recording. In particular, the present invention relates to a liquid ejecting apparatus that prevents an increase in viscosity of a liquid at a nozzle opening.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 10, an ink jet recording head (an example of a head member) has a plurality of nozzle openings 40 (only one is shown in the figure) and a pressure generation communicating with each nozzle opening 40. The chamber 41 and the piezoelectric vibrator 42 that contacts the elastic wall 43 that constitutes a part of the pressure generating chamber are provided. Then, the pressure inside the pressure generating chamber 41 is changed by contracting and expanding the piezoelectric vibrator 42 according to the print signal, and the ink 44 inside the pressure generating chamber 41 is ejected from the nozzle opening 40 by the pressure change. It is configured to discharge as 45.

In a recent color printing apparatus, not only black ink but also a plurality of types of color inks such as yellow (magenta), magenta (magenta), cyan (blue-green) are used as the ink 44. Nozzle openings 40 are provided for each color.

In the recording head as described above, when the recording data is lost and the recording head itself is in a rest state, the ink 44 near the nozzle openings 40 is dried and clogging occurs. Therefore, the recording head is sealed with the cap while the printing operation is not performed. However, if the recording head is left for a long time while being sealed, the solvent of the ink 44 in the vicinity of the nozzle opening 40 is slightly volatilized. As a result, the viscosity rises, and problems such as immediate improper printing and reduced print quality are likely to occur.

Further, the nozzle opening 40, which continuously ejects the ink droplets 45 by the printing operation, uses the new ink 4
4 is sequentially supplied to cause almost no clogging, but at the nozzle opening 40 located at the upper end, the lower end, etc., where the chance of ejecting the ink droplet 45 is extremely low, the ink 44 near the nozzle opening 40 dries during printing. Thickens and tends to cause clogging.

In order to deal with such a problem, as one of the preliminary operations before the start of printing, at the time when the power of the recording apparatus is turned on or when the first print signal is input, regardless of printing. Ink droplets 45 are forced from each nozzle opening 40.
The “flushing operation” and the “cleaning operation” that eliminate the clogging of the nozzle openings 40 and recover the ink droplet ejection capability are performed by ejecting the ink.

The "flushing operation" is to eject the thickened ink 44 around the nozzle opening 40 in advance by applying a drive signal unrelated to print data to the piezoelectric vibrator 42. Further, the "cleaning operation" is performed when the clogging of the nozzle openings 40 is not completely recovered only by the "flushing operation", and a negative pressure is applied to each nozzle opening 40 by a suction pump to generate a pressure. Ink 4 with increased viscosity, such as in chamber 41
4 is forcibly sucked in advance.

Ink in the pressure generating chamber 41 consumed by flushing or printing is stored in the ink storage chamber 48 (see FIG. 11).
Is supplied to the pressure generating chamber 41 from the ink storage chamber 48.
Is supplied from the ink supply hole 52 (see FIG. 11).
At this time, new ink supplied from the ink supply hole 52 easily flows into the pressure generation chamber 41 that is close to the ink supply hole 52, and conversely, to the pressure generation chamber 41 that is far from the ink supply hole 52. Ink does not flow easily. Therefore, inside the ink storage chamber 48, a difference occurs in ink viscosity between a portion near the ink supply hole 52 and a portion far from the ink supply hole 52. For example, in the apparatus shown in FIG. 11, A <in the ink storage chamber 48
A phenomenon occurs in which the viscosity increases in the order of B <C <D.

As described above, when a difference in ink viscosity occurs in the ink storage chamber 48, even if cleaning is performed to suck ink from all the nozzle openings 40, the nozzle openings 40 far from the ink supply holes 52 are cleaned. Since the amount of ink sucked in is small and the ink whose viscosity is increased remains in the pressure generating chamber 41, there is a possibility that the ink ejection capacity of the nozzle opening 40 is not sufficiently recovered. When printing is started in such a state, there is a possibility that a difference in ink droplet ejection performance will occur due to the nozzle openings 40, and print quality will deteriorate.

[0010]

In the above cases, it has been proposed to lengthen the cleaning time in order to recover the ink ejection capacity at the nozzle openings 40 far from the ink supply holes 52. However, even if the cleaning time is lengthened, the ink newly flowing into the nozzle opening 40 near the ink supply hole 52 at the time of cleaning has a lower viscosity, so the suction force at the time of cleaning is the nozzle opening near the ink supply hole 52. In some cases, new ink is wastefully expelled from the ink 40, and the effect on the recovery of the ink ejection capability at the nozzle opening 40 far from the ink supply hole 52 may not be sufficiently recognized.

According to the inventor of the present invention, a cleaning operation of applying a negative pressure to the nozzle opening and discharging the ink while applying pressure fluctuation to the ink in the pressure generating chamber eliminates clogging of the nozzle opening and restores the ink droplet ejection capability. It has been found that it can be extremely effective in achieving this.

However, in the cleaning operation, since the pressure in the ink in the pressure generating chamber is changed at the same time as the negative pressure is applied to the nozzle opening, the pressure is changed while the ink is flowing. Therefore, the flow of ink and the propagation of pressure waves may interfere with each other, adversely affecting the effect of discharging bubbles in the ink flow path.

The present invention has been made in view of the above circumstances, and provides a liquid ejecting apparatus which is excellent in the recovery effect of the liquid droplet ejection capability and can perform the cleaning operation which does not adversely affect the bubble discharging effect in the liquid flow path. The purpose is to provide.

[0014]

SUMMARY OF THE INVENTION According to the present invention, a plurality of nozzle openings, a plurality of pressure generating chambers that communicate with each nozzle opening and can contain a liquid, and a plurality of pressure supplying chambers that supply a liquid. A liquid supply path, a liquid storage chamber in which each liquid supply path is commonly communicated with each other, and a liquid is primarily stored, a liquid supply hole for communicating with the liquid storage chamber, and a liquid pressure in each pressure generation chamber. A plurality of pressure generating means for ejecting a liquid droplet from each nozzle opening by changing
Having a head member, a cleaning means for performing a cleaning operation by sucking liquid in common from the plurality of nozzle openings, a cleaning control means for driving the cleaning means, and the cleaning control means for driving the cleaning means. While corresponding to the nozzle openings grouped into at least one group based on the cleaning control condition set for each group of nozzle openings grouped based on the positional relationship with the liquid supply hole And a cleaning assisting means for driving the pressure generating means for operating the liquid ejecting apparatus.

According to the present invention, during the driving of the cleaning means, the pressure generating means corresponding to the nozzle openings grouped into at least one group based on the positional relationship with the liquid supply hole is driven. With respect to the nozzle openings divided into the groups, the liquid droplet ejection capability can be sufficiently restored.

[0016] Preferably, the cleaning assisting means drives the pressure generating means corresponding to the nozzle openings grouped into the at least one group while the cleaning control means drives the cleaning means. In addition, the pressure generating means corresponding to the nozzle openings divided into other groups are not driven.

In this case, since the pressure generating means corresponding to the nozzle openings grouped into the other group is not driven during the driving of the cleaning means, the nozzle openings grouped into the other group are not flown. The bubble discharging effect inside can be sufficiently maintained. Further, since the driving of the pressure generating means when it is not effective is avoided, the driving cost of the pressure generating means can be reduced and the life of the pressure generating means can be extended.

It is preferable that the corresponding pressure generating means be driven during the driving of the cleaning means only for the nozzle opening farther from the liquid supply hole. That is, preferably, the nozzle openings grouped into the at least one group are nozzle openings farther from the liquid supply hole.

Further, preferably, a leaving time measuring means for measuring the leaving time of the head member is provided, and the cleaning assisting means has a predetermined leaving time measured by the leaving time measuring means. Only when it exceeds the limit, the pressure generating means corresponding to the nozzle openings grouped into the at least one group is driven.

Alternatively, preferably, there are provided capping means for sealing the nozzle openings of the head member, and capping time measuring means for measuring the capping time during which the head member is sealed by the capping means. The cleaning assisting means drives the pressure generating means corresponding to the nozzle openings grouped into the at least one group, only when the capping time measured by the capping time measuring means exceeds a predetermined time. It has become.

Further, preferably, the driving frequency of the pressure generating means by the cleaning assisting means is variable depending on the viscosity of the liquid used in the nozzle openings divided into the at least one group. In this case, the cleaning operation control can be realized in consideration of the difference in the viscosity state of the liquid depending on the type of liquid and the like. In this case, in order to realize high controllability, it is preferable that the nozzle openings grouped into the at least one group use liquids having substantially the same viscosity.

Further, preferably, the cleaning assisting means is a group of nozzle openings grouped based on a positional relationship with the liquid supply hole while the cleaning control means is driving the cleaning means. Based on the cleaning control condition set for each, the pressure generating means corresponding to the nozzle openings divided into at least two groups are driven, and each group of the at least two groups by the cleaning assisting means. The drive frequency of the pressure generating means corresponding to is determined based on the distance between the nozzle openings and the liquid supply holes grouped into each group.

In this case, cleaning is performed on the nozzle openings of each group of the at least two groups according to a driving frequency determined based on the distance between the nozzle openings grouped into each group and the liquid supply hole. Since the corresponding pressure generating means is driven during the driving of the means, stepwise cleaning operation control can be carried out according to the distance from the liquid supply hole.

In this case, preferably, the driving frequency of the pressure generating means corresponding to each group of the at least two groups by the cleaning assisting means is the viscosity of the liquid used in the nozzle openings grouped into each group. Dependent and variable. In this case, the cleaning operation control can be realized in consideration of the difference in the viscosity state of the liquid depending on the type of liquid and the like. In this case, in order to realize high controllability, it is preferable that the nozzle openings grouped into each of the at least two groups use liquids having substantially the same viscosity for each group. .

Further, according to the present invention, a plurality of nozzle openings, a plurality of pressure generating chambers communicating with each nozzle opening and capable of containing a liquid, and a plurality of liquid supply paths for supplying a liquid to each pressure generating chamber, Each liquid supply path is commonly communicated with each other, and a liquid storage chamber that primarily stores the liquid, a liquid supply hole that communicates with the liquid storage chamber, and a liquid supply hole for supplying the liquid, and change the pressure of the liquid in each pressure generation chamber. A liquid ejecting apparatus including a head member having a plurality of pressure generating means for ejecting liquid droplets from each nozzle opening, and a cleaning means for sucking the liquid in common from the plurality of nozzle openings to perform a cleaning operation. And a cleaning control unit that drives the cleaning unit,
While the cleaning control unit is driving the cleaning unit, at least one of the nozzle openings is grouped based on the positional relationship with the liquid supply hole, based on the cleaning control condition set for each group. And a cleaning auxiliary means for driving a pressure generating means corresponding to the nozzle openings divided into two groups.

The cleaning control means and the cleaning auxiliary means can be realized by a computer system.

Further, a program for realizing each means in a computer system and a computer-readable recording medium recording the program are also covered by the present protection.

Specifically, a program executed by a computer system including at least one computer to cause the computer system to realize the control device is a subject of protection of the present case. A computer-readable recording medium recording the program is also a subject of protection in this case.

Further, an instruction for controlling a second program operating on a computer system including at least one computer is included, and the instruction is executed by the computer system to control the second program. A program that causes the computer system to realize the control device is also a protection target of the present case. A computer-readable recording medium recording the program is also a subject of protection in this case.

Here, the recording medium includes a medium which can be recognized as a single body such as a floppy (registered trademark) disk and a network which propagates various signals.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described in detail.

FIG. 1 is a diagram showing an example of the peripheral structure of an ink jet recording apparatus to which the present invention is applied. This device has six ink cartridges 7 mounted on the top,
A carriage 1 having a recording head 6 attached to its lower surface,
A capping device 8 for sealing the recording head 6 is provided. The inside of the ink cartridge 7 is divided into six ink chambers, and in each ink chamber, cyan (C), light cyan (LC), magenta (M), light magenta (LM), yellow (Y), black ( B
Six types of ink of K) are stored.

The carriage 1 is provided with a timing belt 2
It is connected to a pulse motor 3 (stepping motor) via a guide bar 4, and is guided by a guide bar 4 to reciprocate in the paper width direction of the recording paper 5. The surface of the carriage 1 that faces the recording paper 5 (the lower surface in this example)
The recording head 6 is attached to. Then, ink is supplied from the ink cartridges 7 to the recording head 6, and ink droplets are ejected onto the upper surface of the recording paper 5 while moving the carriage 1 to print an image or characters on the recording paper 5 by a dot matrix. ing.

The capping device 8 comprises the carriage 1
It is provided in a non-printing area within the moving range of No. 2 and is designed to prevent the nozzle opening from drying as much as possible by sealing the nozzle opening of the recording head 6 during printing suspension. The capping device 8 also acts as a container for receiving ink droplets ejected from the recording head 6 by the flushing operation. Further, the capping device 8 is connected to a suction pump 9 and applies a negative pressure to the nozzle opening of the recording head 6 to suck ink from the nozzle opening during the cleaning operation.

FIG. 2 is a diagram showing an example of the recording head 6. The recording head 6 includes a base 11 and the base 1.
Piezoelectric vibrator 13 vibratably accommodated in the first accommodation chamber 12
And the flow path unit 14 fixed to the lower surface of the base 11.
It has and.

The flow path unit 14 includes a nozzle plate 16 having a plurality of nozzle openings 15 formed in a row, a thin vibrating plate 21 that elastically deforms, and the nozzle plate 16 described above.
And the flow path forming plate 20 sandwiched between the vibration plates 21 and fixed in a liquid-tight manner. The flow path forming plate 20 has a plurality of pressure generating chambers 17 communicating with each of the nozzle openings 15, an ink chamber 18 (liquid storage chamber) supplied with ink from the ink cartridge 7, and a plurality of ink chambers 18 from which the ink is supplied. A space corresponding to an ink supply path 19 for supplying ink to the pressure generating chamber 17 is formed. And
Separate ink chambers 18 and rows of nozzle openings 15 are provided for each of the six types of ink colors.

The piezoelectric vibrator 13 is attached to the support substrate 22, and the support substrate 22 is used for the accommodation chamber 12 of the base 11.
By being fixed inside, it is vibratably accommodated in the accommodation chamber 12. The lower end of the piezoelectric vibrator 13 is connected to the island portion 2 of the diaphragm 21 of the flow path unit 14.
It is bonded to 1a. In the figure, 23 is a signal cable for sending a drive signal to the piezoelectric vibrator 13, and 25 is an ink supply hole for supplying ink to the ink chamber 18. The ink chamber 18 has a function of commonly connecting the ink supply paths 19 (see FIG. 4) and a function of primarily storing ink.

The recording head 6 performs printing, for example, as follows. That is, first, when the piezoelectric vibrator 13 is charged and contracts, the pressure generating chamber 17 expands and the internal pressure decreases. As a result, the nozzle opening 1
The meniscus 5 is slightly drawn into the pressure generating chamber 17, and the ink in the ink chamber 18 is supplied to the pressure generating chamber 17 through the ink supply passage 19.

Then, after a lapse of a predetermined time, the piezoelectric vibrator 1
When the electric charge of 3 is discharged and the piezoelectric vibrator 13 returns to the original state, the pressure generating chamber 17 contracts and the internal pressure increases. As a result, the ink in the pressure generating chamber 17 is compressed and ejected as an ink droplet from the nozzle opening 15, and the ink droplet is ejected onto the upper surface of the recording paper 5 to print an image or a character.

FIG. 3 is a schematic view showing the first embodiment of the ink jet recording apparatus of the present invention. In FIG. 3, reference numeral 30 denotes a printer controller that receives various data from a host (not shown). The details will be described later with reference to FIG. 9, but a drive voltage is applied to the piezoelectric vibrator 13 in response to a print signal. A printing operation of applying and ejecting ink droplets from the recording head 6 is executed. In addition, in response to the flushing command, a drive voltage that is not related to the print signal is applied to the piezoelectric vibrator 13, and a flushing operation of ejecting ink droplets from each nozzle opening 15 of the recording head 6 is executed. further,
During a cleaning operation in a cleaning assist mode, which will be described later, a drive voltage irrelevant to the print signal is applied to the piezoelectric vibrator 13 to change the ink pressure in a desired nozzle opening 15 of the recording head 6.

Reference numeral 32 denotes a pump drive means, which applies a negative pressure to the recording head 6 sealed by the capping device 8 (capping means) by the suction pump 9 to forcibly suck ink from all nozzle openings 15. Perform the cleaning operation.

A cleaning control means 31 receives a signal from the host and controls the cleaning operation by the pump drive means 32.

Reference numeral 34 denotes a capping timer (capping time measuring means), which is activated upon detecting that the recording head 6 is sealed by the capping device 8, and in a state where the recording head 6 is sealed by the capping means 8. Measure the left-over capping time. Further, 35 is a leaving timer (leaving time measuring means), which measures the time when the recording head 6 is left in a state of being released from the capping device 8. The capping timer 34 and the leaving timer 3
All of 5 are reset when a signal is output.

Reference numeral 33 denotes a mode selecting means, which receives a signal of the capping time output from the capping timer 34 or the leaving time output from the leaving timer 35 and does not operate the piezoelectric vibrator 13 for each color ink. Either the normal mode or the cleaning assist mode for operating the piezoelectric vibrator 13 is selected, and the signal of the selected mode is output to the printer controller 30 and the cleaning control means 31.

FIG. 4 is a plan view showing the flow path forming plate 20 and the nozzle plate 16 in the recording head of the ink jet recording apparatus. As shown in FIG. 4, based on the positional relationship with the ink supply holes 25, the group (group) of the nozzle openings 15 communicating with the pressure generating chambers 17 arranged relatively close to the ink supply holes 25 is C The nozzle openings 15 are grouped (set). Further, based on the positional relationship with the ink supply holes 25, the group of nozzle openings 15 communicating with the pressure generating chambers 17 arranged relatively far from the ink supply holes 25 are grouped as the nozzle openings 15 of the A group. Has been done. Based on the positional relationship with the ink supply holes 25, the group of nozzle openings 15 that communicates with the pressure generating chamber 17 located at a distance between the ink supply holes 25 and the groups A and C is the group B. The nozzle openings 15 are grouped.

In this embodiment, each nozzle opening 15
The grouping of is stored in the printer controller 30. The internal structure of the printer controller 30 will be described later with reference to FIG.

FIG. 5 is an explanatory diagram showing an example of the mode selection conditions depending on the capping time in the ink jet recording apparatus. In this example, FIG.
As shown in (c), the capping time is divided into three areas of less than 1 month, 1 to 2 months, and 2 months or more.

In general, as the capping time becomes longer, the viscosity of the ink increases, and the ink ejection capability of the nozzle openings decreases. Further, with respect to the nozzle opening 15 far from the ink supply hole 25, the amount of ink sucked by a normal cleaning operation is not sufficient, and there is a possibility that the thickened ink remains in the pressure generating chamber 17. Therefore, for the nozzle opening 15 far from the ink supply hole 25, when the capping time exceeds the predetermined time, the cleaning assist mode for activating the corresponding piezoelectric vibrator 13 is selected, and particularly the farther from the ink supply hole 25. For the nozzle opening 15, the predetermined time is set to be short.

In this embodiment, as shown in FIG. 5A, for the nozzle openings 15 of the group A far from the ink supply holes 25, the cleaning normal mode is selected if the capping time is less than one month. The cleaning assist mode is selected when the capping time is one month or more.

Further, as shown in FIG. 5B, the nozzle openings 1 of the group B having a medium distance from the ink supply hole 25.
Regarding No. 5, if the capping time is less than 2 months, the cleaning normal mode is selected.
If the capping time is 2 months or more, the cleaning assist mode is selected.

On the other hand, as shown in FIG. 5C, for the nozzle openings 15 of the group C that are relatively close to the ink supply holes 25, the cleaning normal mode is selected regardless of the capping time. ing.

Although the relationship between the standing time and the mode selection condition is substantially the same as the relationship between the capping time and the mode selection condition shown in FIG. 5, 1 and 2 months, which are the division standard values for the capping time, , The standing time can be read as 1 week and 2 weeks.

The values of 1 month and 2 months, which are the standard values for the capping time, and 1 week and 2 weeks, which are the standard values for the leaving time, are all set to the temperature standard value of 40 ° C. It is an experimentally derived value by the present inventor based on this. Preferably, each of these values can be modified according to the temperature or humidity of the environment in which the inkjet recording apparatus is actually installed.

Here, an example of the operation of the ink jet recording apparatus will be described with reference to the flow chart shown in FIG. In addition, in FIG. 6, "S" means a step.

First, when the cleaning operation command is issued from the host, the capping time by the capping timer 34 is detected (S1). Alternatively, the leaving time is detected by the leaving timer 35 (S1). Next, the mode selection means 33 selects the cleaning normal mode or the cleaning assist mode for each group of the nozzle openings 15 grouped based on the obtained capping time or the standing time (S2).

When the cleaning normal mode is selected, the cleaning operation is carried out by the pump driving means 32 and the suction pump 9 (S3).

When the cleaning assist mode is selected, the cleaning operation is carried out by the pump driving means 32 and the suction pump 9 as well. During the operation of the suction pump 9, the piezoelectric vibration corresponding to the nozzle opening 15 belonging to the relevant group. The child 13 is driven (S4).

Note that, for example, the drive frequency of the piezoelectric vibrator 13 during the operation of the suction pump 9 may be the basic frequency of the drive signal for printing 8.64 kHz × 3 = 25.9.
It is 2 kHz.

As described above, according to the above-mentioned ink jet recording apparatus, regarding the nozzle openings 15 of the group A and the group B which are relatively far from the ink supply hole 25, the piezoelectric vibrator during the operation of the suction pump 9 (during the cleaning operation). Since the nozzle 13 is driven, the recovery of the ink droplet ejection capability at the nozzle opening 15 is sufficiently achieved.

On the other hand, C which is relatively close to the ink supply hole 25
With respect to the nozzle openings 15 of the group, since the piezoelectric vibrator 13 is not driven during the operation of the suction pump 9 (during the cleaning operation), the effect of eliminating bubbles in the ink flow path communicating with the nozzle openings 15 may be adversely affected. Absent. Further, since it is possible to avoid driving the piezoelectric vibrator 13 which is not particularly necessary, the driving cost of the piezoelectric vibrator 13 is reduced and the life thereof is not unnecessarily shortened.

The driving frequency of the piezoelectric vibrator 13 during the operation of the suction pump 9 can be changed appropriately. The drive frequency can be changed by increasing or decreasing the frequency itself of the basic waveform. Alternatively, changing the drive frequency
It can also be done by increasing or decreasing the number of pulse waveforms selected (picked up) from the basic waveform.

For example, as shown in FIG. 7, the ink supply hole 2
For the nozzle openings 15 of group A, which are relatively far from 5, the capping time is 1 to 2 months (or the leaving time is 1 to
2 weeks), the corresponding piezoelectric vibrator 13 is driven at a drive frequency of 25.92 kHz, while when the capping time is 2 months or more (leaving time is 2 weeks or more). It is preferable that the corresponding piezoelectric vibrator 13 is driven at a driving frequency F of over 25.92 kHz. That is, it is preferable that a plurality of drive frequencies be set stepwise with respect to the capping time (or the standing time).

The grouping of the nozzle openings 15 into the groups A to C as described above can be performed for each row of nozzle openings formed in a row. The mode of grouping into groups A to C may be the same for each column or different for each column.
This is because the ink discharge characteristic and the ink thickening characteristic at the time of cleaning the nozzle openings can be influenced by the structural factors of the nozzle openings that are usually formed in each row.

Further, in this case, the drive frequency for driving the piezoelectric vibrators 13 in the cleaning assist mode may be common for each column, or may be different for each column. In particular, when the type (for example, color) of the ink supplied to the nozzle openings 15 differs from column to column, the viscous state of the ink may differ from column to column, so it is possible to use different drive frequencies for each column. Can be valid.

In this case, it is preferable that a higher driving frequency is used for the ink whose viscosity is more easily increased. Alternatively, the higher the actual viscosity of the ink, the higher the drive frequency used. In this case, the driving frequency is set stepwise according to the viscosity of the ink, and the stepwise driving of the piezoelectric vibrator 13 during the cleaning operation can be realized.

In addition, the nozzle opening 15 is connected to the ink supply hole 25.
The mode of grouping based on the positional relationship with is not limited to the above embodiment, and various changes can be made. For example,
Instead of the three groupings A to C, grouping into two groups or grouping into four or more groups may be adopted. Further, the number of nozzle openings 15 included in each group is also arbitrary.

Further, as shown in FIG. 8, the ink supply hole 2
The present invention can be applied even when 5 is not provided in the center of the ink chamber 18. In the case of the arrangement shown in FIG. 8, the cleaning auxiliary effect by driving the piezoelectric vibrator 13 at the nozzle opening 15 (of the group A or the group B) far from the ink supply hole 25 is extremely useful.

Here, an example of the printer controller 30 in the above embodiment will be described in detail with reference to FIG.

The printer controller 30 includes an external interface (external I / F) 132, a RAM 133 for temporarily storing various data, a ROM 134 for storing control programs and the like, and a control section 111 including a CPU and the like. And an oscillator circuit 135 for generating a clock signal
A drive signal generating circuit 136 for generating a drive signal COM to be supplied to the recording head 6, and a drive signal, dot pattern data (bitmap data) developed based on print data, and the like to the print engine 131. And an internal interface (internal I / F) 137 that operates.

The external I / F 132 receives print data composed of, for example, a character code, a graphic function, image data, etc. from a host computer (not shown) or the like. Further, a busy signal (BUSY) and an acknowledge signal (ACK) are output to the host computer or the like through the external I / F 132.

The RAM 133 has a reception buffer, an intermediate buffer, an output buffer and a work memory (not shown). Then, the reception buffer is the external I / F 13
The print data received via 2 is temporarily stored, the intermediate buffer stores the intermediate code data converted by the control unit 111, and the output buffer stores the dot pattern data. Here, the dot pattern data is
It is print data obtained by decoding (translating) intermediate code data (for example, gradation data).

The ROM 134 stores font data, graphic functions, etc. in addition to a control program (control routine) for performing various data processing.
Further, the ROM 134 also stores setting data for maintenance operation as a maintenance information holding unit.

The control unit 111 performs various controls according to the control program stored in the ROM 134. For example,
The print data in the reception buffer is read, the print data is converted into intermediate code data, and the intermediate code data is stored in the intermediate buffer. In addition, the control unit 1
Reference numeral 11 analyzes the intermediate code data read from the intermediate buffer, and with reference to the font data, the graphic function, etc. stored in the ROM 134, develops (decodes) the dot pattern data. Then, the control unit 111
Stores the dot pattern data in the output buffer after performing the necessary decoration processing.

If dot pattern data for one line that can be printed is obtained by one main scan of the print head 6,
The dot pattern data for one line is sequentially output from the output buffer to the electric drive system 139 of the recording head 6 through the internal I / F 137, and the carriage 1 is scanned to print one line. When one line of dot pattern data is output from the output buffer, the expanded intermediate code data is erased from the intermediate buffer, and expansion processing is performed on the next intermediate code data.

Further, the control section 111 controls the maintenance operation (recovery operation) performed prior to the recording operation by the recording head 6.

The print engine 131 includes a paper feed motor 113 as a paper feed mechanism, a pulse motor 3 as a head scanning mechanism, and an electric drive system 139 for the recording head 6.
And are included.

Further, the electric drive system 139 of the recording head 6 will be described. As shown in FIG. 9, the electric drive system 139 includes a shift register circuit 14 electrically connected in order.
0, a latch circuit 141, a level shifter circuit 142, a switch circuit 143, and the piezoelectric vibrator 13. The shift register circuit 140, the latch circuit 141, the level shifter circuit 142, the switch circuit 143, and the piezoelectric vibrator 13 are respectively provided in the nozzle openings 1 of the recording head 6.
It is provided every five.

In this electric drive system 139, when the bit data applied to the switch circuit 143 is "1", the switch circuit 143 is in the connected state and the drive signal (COM) is directly applied to the piezoelectric vibrator 13 to cause each piezoelectric element. The vibrator 13 is deformed according to the signal waveform of the drive signal. On the other hand, when the bit data applied to the switch circuit 143 is “0”, the switch circuit 143 is disconnected and the supply of the drive signal to the piezoelectric vibrator 14 is cut off.

As described above, the drive signal can be selectively supplied to each piezoelectric vibrator 13 based on the bit data. Therefore, it is possible to eject ink droplets from the nozzle openings 15 or to slightly vibrate the meniscus, depending on the bit data given.

During the cleaning operation, the piezoelectric vibrators 13 corresponding to the nozzle openings 15 divided into predetermined groups.
The control mode of the above-described embodiment in which only the driving is performed can be performed by controlling the bit data, thereby performing the printhead control similar to that at the time of printing.

In the above embodiment, an example in which the present invention is applied to the ink jet recording apparatus having the recording head 6 using the piezoelectric vibrator 13 which expands and contracts in the axial direction is shown, but the invention is not limited to this. Instead, it may be applied to an ink jet recording apparatus having a recording head that expands and contracts the pressure generating chamber 17 by flexural vibration, a bubble jet (registered trademark) recording head, or the like. In this case as well, the same effect is obtained.

The flushing operation or the cleaning operation can be performed by moving the carriage to a predetermined flushing position or cleaning position, respectively.

Further, in each of the above embodiments, at least a part of the printer controller 30, the cleaning control means 31, the pump drive means 32, the mode selection means 33, the capping timer 34, and the leaving timer 35 can be realized by a computer system. .

In this case, the computer-readable recording medium 201 in which the program for realizing the above-mentioned respective elements in the computer system is recorded is also the subject of protection of the present case.

Further, when each of the above-mentioned elements is realized by a program (second program) such as an OS operating on a computer system, a program (second program) including various instructions for controlling the program such as the OS is provided. The recording medium 202 in which the program) is recorded is also a protection target of the present case.

Although the above description has been made with respect to the ink jet recording apparatus, the present invention is broadly applicable to all liquid ejecting apparatuses. As an example of the liquid, in addition to ink, glue, nail polish, a conductive liquid (liquid metal) for forming a circuit, or the like can be used. Furthermore, the present invention can be applied to an apparatus for manufacturing a color filter in a display body such as a liquid crystal.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an ink jet recording apparatus according to the present invention.

FIG. 2 is a cross-sectional view showing an example of an inkjet recording head.

FIG. 3 is a schematic block diagram showing an embodiment of an ink jet recording apparatus according to the present invention.

FIG. 4 is a plan view showing a flow path forming plate and a nozzle plate for explaining one mode of grouping nozzle openings.

FIG. 5 is a diagram for explaining an example of a relationship between a capping time and a cleaning mode.

6 is a flowchart showing the operation of the ink jet recording apparatus of FIG.

FIG. 7 is a diagram for explaining another example of the relationship between the capping time and the cleaning mode.

FIG. 8 is a plan view showing a flow path forming plate and a nozzle plate for explaining another mode of grouping nozzle openings.

FIG. 9 is a block diagram showing details of a printer controller.

FIG. 10 is a partially cutaway cross-sectional view showing an inkjet recording head of a conventional example, in which (a) is a steady state, (b) is a state in which a piezoelectric vibrator is contracted, and (c) is a state in which ink droplets are ejected. is there.

FIG. 11 is a plan view showing a flow path forming plate and a nozzle plate in a conventional inkjet recording head.

[Explanation of symbols]

1 carriage 2 Timing belt 3 pulse motor (stepping motor) 4 Guide bar 5 recording paper 6 recording head 7 ink cartridges 8 capping device 9 Suction pump 11 bases 12 accommodation room 13 Piezoelectric vibrator 14 flow path unit 15 nozzle opening 16 nozzle plate 17 Pressure generation chamber 18 ink chamber 19 ink supply path 20 flow path forming plate 21 diaphragm 21a Island part 22 Support substrate 23 signal cable 25 Ink supply hole 30 Printer controller 31 cleaning control means 32 Pump drive means 33 Mode selection means 34 capping timer 35 Abandoned timer 111 control unit 113 Paper feed motor 131 print engine 132 External interface 133 RAM 134 ROM 135 oscillator circuit 136 Drive signal generation circuit 137 Internal interface 139 Electric drive system for recording head 140 shift register circuit 141 Latch circuit 142 level shifter circuit 143 switch circuit

Claims (16)

[Claims] 1. A plurality of nozzle openings, a plurality of pressure generating chambers that communicate with each nozzle opening and can store a liquid, a plurality of liquid supply paths that supply a liquid to each pressure generating chamber, and a respective liquid supply. A liquid storage chamber in which the channels are commonly communicated with each other and which primarily stores the liquid, a liquid supply hole which communicates with the liquid storage chamber, and a liquid supply hole for supplying the liquid, and the nozzle opening by changing the pressure of the liquid in each pressure generation chamber A head member having a plurality of pressure generating means for ejecting liquid droplets from the nozzle, a cleaning means for performing a cleaning operation by commonly sucking the liquid from the plurality of nozzle openings, and a cleaning control means for driving the cleaning means. And nozzles grouped based on the positional relationship with the liquid supply holes while the cleaning control unit is driving the cleaning unit. A cleaning assisting means for driving pressure generating means corresponding to the nozzle openings grouped into at least one group based on the cleaning control condition set for each group of mouths, Injection device. 2. The cleaning auxiliary means drives the pressure generating means corresponding to the nozzle openings grouped into the at least one group while the cleaning control means drives the cleaning means. The liquid ejecting apparatus according to claim 1, wherein the pressure generating means corresponding to the nozzle openings divided into other groups is not driven. 3. The liquid ejecting apparatus according to claim 1, wherein the nozzle openings grouped into the at least one group are nozzle openings farther from a liquid supply hole. 4. A leaving time measuring means for measuring a leaving time of the head member is left, and the cleaning assisting means has a leaving time measured by the leaving time measuring means exceeding a predetermined time. 4. The liquid ejecting apparatus according to claim 1, wherein the pressure generating means corresponding to the nozzle openings divided into the at least one group is driven only in this case. 5. The cleaning aid further comprises: capping means for sealing a nozzle opening of the head member; and capping time measuring means for measuring a capping time during which the head member is sealed by the capping means. The means drives the pressure generating means corresponding to the nozzle openings grouped into the at least one group only when the capping time measured by the capping time measuring means exceeds a predetermined time. 5. The method according to claim 1, wherein
The liquid ejecting apparatus according to any one of 1. 6. The driving frequency of the pressure generating means by the cleaning assisting means is variable depending on the viscosity of the liquid used in the nozzle openings grouped into the at least one group. Item 6. The liquid ejecting apparatus according to any one of Items 1 to 5. 7. The cleaning assisting means is set for each group of nozzle openings grouped based on a positional relationship with the liquid supply hole while the cleaning control means is driving the cleaning means. The pressure generating means corresponding to the nozzle openings grouped into at least two groups is driven on the basis of the cleaning control conditions set, and the cleaning assisting means corresponds to each group of the at least two groups. 7. The driving frequency of the pressure generating means is determined based on the distance between the nozzle openings and the liquid supply holes, which are grouped into each of the groups, respectively. Liquid ejector. 8. The drive frequency of the pressure generating means corresponding to each group of the at least two groups by the cleaning assisting means depends on the viscosity of the liquid used in the nozzle openings grouped into each group, The liquid ejecting apparatus according to claim 7, wherein the liquid ejecting apparatus is variable. 9. A plurality of nozzle openings, a plurality of pressure generating chambers that communicate with each nozzle opening and can store a liquid, a plurality of liquid supply paths that supply a liquid to each pressure generating chamber, and a respective liquid supply. A liquid storage chamber in which the channels are commonly communicated with each other and which primarily stores the liquid, a liquid supply hole which communicates with the liquid storage chamber, and a liquid supply hole for supplying the liquid, and the nozzle opening by changing the pressure of the liquid in each pressure generation chamber A liquid ejecting apparatus including a head member having a plurality of pressure generating means for ejecting liquid droplets from the head, and a cleaning means for performing a cleaning operation by commonly sucking the liquid from the plurality of nozzle openings. A controller for controlling the cleaning means, the cleaning control means driving the cleaning means, and the cleaning control means driving the cleaning means while the cleaning means is driving the cleaning means. Based on the cleaning control condition set for each group of nozzle openings grouped based on the positional relationship with the supply hole, the pressure generating means corresponding to the nozzle openings grouped into at least one group is driven. A cleaning assisting means, and a control device. 10. The cleaning assisting means drives the pressure generating means corresponding to the nozzle openings grouped into the at least one group while the cleaning control means drives the cleaning means. 10. The control device according to claim 9, wherein the pressure generating means corresponding to the nozzle openings divided into other groups are not driven. 11. The control device according to claim 9, wherein the nozzle openings grouped into the at least one group are nozzle openings farther from a liquid supply hole. 12. The cleaning apparatus further comprises a standing time measuring means for measuring a standing time of the head member, wherein the cleaning auxiliary means has a standing time measured by the standing time measuring means exceeding a predetermined time. The control device according to any one of claims 9 to 11, wherein the pressure generating means corresponding to the nozzle openings divided into the at least one group is driven only in this case. 13. The cleaning aid further comprises: capping means for sealing a nozzle opening of the head member; and capping time measuring means for measuring a capping time during which the head member is sealed by the capping means. The means drives the pressure generating means corresponding to the nozzle openings grouped into the at least one group only when the capping time measured by the capping time measuring means exceeds a predetermined time. Claims 9 to 1 characterized in that
2. The control device according to any one of 2. 14. The driving frequency of the pressure generating means by the cleaning assisting means is variable depending on the viscosity of the liquid used in the nozzle openings divided into the at least one group. Item 14. The control device according to any one of Items 9 to 13. 15. The cleaning auxiliary means is set for each group of nozzle openings grouped based on the positional relationship with the liquid supply hole while the cleaning control means is driving the cleaning means. The pressure generating means corresponding to the nozzle openings grouped into at least two groups is driven on the basis of the cleaning control conditions set, and the cleaning assisting means corresponds to each group of the at least two groups. 15. The driving frequency of the pressure generating means is determined based on the distance between the nozzle openings and the liquid supply holes, which are grouped into each of the groups, respectively. Control device. 16. The driving frequency of the pressure generating means corresponding to each group of the at least two groups by the cleaning assisting means depends on the viscosity of the liquid used in the nozzle openings grouped into each group, The control device according to claim 15, wherein the control device is variable.