JP2011098538A - Liquid jetting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress liquid from being ejected without being used even when a content component sediments in the liquid to be jetted. <P>SOLUTION: In the liquid jetting apparatus which performs operation to eject the liquid from a jetting nozzle in order to avoid a sedimenting component in the liquid from sedimenting in a jetting head or in a liquid path, elapsed time after the liquid is ejected is measured, and a number of times (number of direction changing times) of changing a direction as the jetting head moves back and forth after the liquid is ejected is counted. When ejecting the liquid, the degree of sedimentation of the liquid in the liquid path is exactly known considering the measured elapsed time and the counted number of times of changing the direction. Thus, the liquid is appropriately ejected according to the degree of the sedimentation of the liquid. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technique for ejecting liquid from an ejection nozzle.

A liquid ejecting apparatus that ejects liquid such as ink from an ejecting head provided with a fine ejecting nozzle is known. In this liquid ejecting apparatus, the liquid (for example, ink) to be ejected
Is stored in a dedicated container (for example, an ink cartridge), and the liquid in the container is ejected by supplying it to the ejection head through the passage.

Moreover, a sedimentary component may be used for the component of the liquid to be ejected. For example, in the case of ink, a pigment may be used for the purpose of improving so-called weather resistance or improving color developability. Since the pigment is suspended without dissolving in the ink solvent (water, alcohol, etc.), the pigment settles in the solvent if the ink is left for a long period of time. As a result, a dark portion and a thin portion of the pigment concentration occur in the ink,
The image cannot be printed properly.

Therefore, in an ink jet printer equipped with an ink containing a sedimenting component (hereinafter referred to as “sedimenting ink”), when it is determined that ink sedimentation has occurred in the ejection head,
There has been proposed a technique for discharging ink that has proceeded to settle by sucking ink from an ejection nozzle (Patent Document 1).

JP 2002-234196 A

However, sedimentation of the contained components in the liquid to be ejected (such as ink) occurs not only in the interior of the ejection head but also in the passage for supplying the liquid from the storage container to the ejection head. When ink sedimentation occurs in the passage in this way, it is possible to eliminate the adverse effects of ink sedimentation by discharging all of the liquid in the ejection head and the liquid in the passage. There is a problem that will be wasted. In particular, in a liquid ejecting apparatus in which a dedicated container for storing liquid is provided at a position away from the ejecting head and the liquid is supplied to the ejecting head via a long tube or the like, a large amount of liquid present in the tube is removed. These problems are even more pronounced because they must be discharged.

The present invention has been made in response to the above-described problems in the prior art, and even when sedimentation of contained components occurs in the liquid to be ejected, it is possible to suppress discharging the liquid without using it. Aims to provide a new technology.

In order to solve at least a part of the problems described above, the liquid ejecting apparatus of the present invention employs the following configuration. That is,
A liquid ejecting apparatus that ejects liquid from the ejection nozzle while reciprocating the ejection head provided with the ejection nozzle,
A liquid container containing a liquid containing a sedimentary component;
A liquid passage for guiding the liquid in the liquid container to the ejection head;
In order to avoid the sedimentation component contained in the liquid from settling in the ejection head or the liquid passage, the liquid is ejected from the ejection nozzle at a predetermined location on the path along which the ejection head reciprocates. Liquid discharging means for discharging;
Time measuring means for measuring the elapsed time since the liquid discharging means discharged the liquid at the predetermined location;
A counting means for counting the number of times of turning, which is the number of times of turning when the jet head reciprocates after the liquid discharging means discharges the liquid at the predetermined location, and
The liquid discharge means is a means for discharging the liquid in consideration of the elapsed time and the number of direction changes when discharging the liquid at the predetermined location.

In such a liquid ejecting apparatus of the present invention, the liquid is supplied to the ejecting head through the liquid passage from the liquid containing portion containing the liquid containing the sedimenting component, and the ejecting head is reciprocated while the ejecting head is reciprocated. A liquid is ejected from an ejection nozzle provided in the nozzle. In order to avoid this sedimentation component contained in the liquid settles in the ejection head or in the liquid passage, the liquid is discharged from the ejection nozzle at a predetermined location on the path along which the ejection head reciprocates. . When the liquid is discharged at a predetermined location, the elapsed time after the liquid is discharged is counted, and the number of times the direction is changed as the ejection head reciprocates after the liquid is discharged at the predetermined location. Count). When the liquid is discharged at a predetermined location, the liquid is discharged in consideration of the elapsed time measured and the counted number of direction changes.

Here, “injection” and “discharge” are common in that the liquid is discharged from the injection nozzle, but “injection” in this specification refers to the injection from the injection nozzle in accordance with the original purpose of the liquid injection device. This refers to discharging the liquid. On the other hand, “discharging” is not the original purpose of the liquid discharging device, but to prevent sedimentation components in the liquid from settling in the ejection head or the liquid passage. In this case, the liquid is ejected from the spray nozzle.

When the ejection head reciprocates, a change of direction occurs, and at this time, a large acceleration acts on the liquid in the ejection head and the fluid passage. This acceleration action appears more strongly in the sedimentation component having a larger specific gravity than the solvent in the liquid, so that the sedimented component is stirred so as to roll up in the solvent each time the direction is changed. . Therefore, even if the elapsed time from the previous discharge of the liquid is the same, if the ejecting head reciprocates during that time, sedimentation of the sedimentary component that occurs in the liquid in the liquid passage is suppressed. Yes. Therefore, in the liquid ejecting apparatus of the present invention, considering the number of times the direction of the ejection head has changed reciprocally after the previous liquid discharge (the number of direction changes) along with the elapsed time from the previous liquid discharge, Drain the liquid. This makes it possible to discharge a required amount of liquid according to the degree of sedimentation in the liquid, thereby reducing the amount of liquid discharged without being used for the original purpose of the liquid ejecting apparatus. be able to.

In the above-described liquid ejecting apparatus of the present invention, when discharging the liquid from the ejecting nozzle,
Rather than taking into account the time during which the ejection head reciprocated after the previous liquid was discharged, the number of times the jet head changed its direction after the previous liquid discharge was taken into account. For this reason, for example, when printing on printing paper with a narrow paper width, the number of times of direction change is large for the time the ejecting head has reciprocated, and therefore, the sedimentary component generated in the liquid in the liquid passage In the case where settling has been significantly suppressed, or conversely, because the paper width is wide, the number of times of direction change is small for the time the jet head has reciprocated, and so settling of sedimentary components in the liquid is suppressed so much. Even when there is not, it is possible to accurately grasp the degree of sedimentation of the sedimentary component in the liquid passage. For this reason, it becomes possible to reduce the quantity of the liquid discharged | emitted by discharging | emitting a liquid by the required quantity according to the grade of sedimentation.

In such a liquid ejecting apparatus of the present invention, the liquid may be discharged as follows. First, as a discharge operation for discharging a predetermined amount of liquid from the ejection nozzle, a discharge operation storage means for storing a plurality of discharge operations with different discharge amounts is provided. Then, when discharging the liquid from the ejection nozzle, it is stored in the discharge operation storage means based on the elapsed time from the previous liquid discharge and the number of direction changes of the ejection head after the previous liquid discharge. A discharge operation may be selected from a plurality of discharge operations, and the liquid may be discharged from the ejection nozzle according to the selected discharge operation.

As described above, if a plurality of discharge operations having different discharge amounts are stored, the discharge operation corresponding to the combination of the elapsed time from the previous discharge of the liquid and the number of times of change in the direction is selected. The discharging operation can be started immediately.

In such a liquid ejecting apparatus of the present invention, the liquid may be discharged as follows. First, a recess for receiving the liquid discharged from the ejection nozzle is formed, and a liquid receiving portion that forms a closed space around the ejection nozzle by contacting the ejection head is provided. A suction pump connected to the recess is provided. Then, the liquid may be discharged from the ejection nozzle by operating the suction pump while the liquid receiving portion is in contact with the ejection head.

According to such a configuration, while the ejecting head is not reciprocating, the liquid receiving portion is kept in contact with the ejecting head, so that drying of the liquid proceeds from the ejecting nozzle (the volatile component in the liquid is reduced). Can be effectively suppressed. When the liquid is discharged from the ejection nozzle, the negative pressure can be applied to the closed space around the ejection nozzle only by operating the suction pump while keeping the liquid receiving portion in contact with the ejection head. This allows the liquid to be sucked out of the jet nozzle. Therefore, it is possible to easily discharge the liquid that has settled in the ejection head or the liquid passage.

It is explanatory drawing which illustrated the inkjet printer as a liquid ejecting apparatus of a present Example. It is explanatory drawing which showed the rough structure of the drive part for reciprocating an ejection head, and the paper feed part for feeding roll paper. It is explanatory drawing which showed notionally the mode that the inkjet printer of a present Example prints an image, reciprocating the ejection head. It is explanatory drawing which showed notionally the mode that sedimentation of the ink generate | occur | produces in an ink tube. FIG. 4 is an explanatory diagram illustrating a state in which an ink tube moves with the reciprocation of an ejection head. It is explanatory drawing which showed a mode that a sedimentation component was stirred in the horizontal part of an ink tube. It is the flowchart which showed the maintenance operation | movement selection process performed before the inkjet printer of a present Example starts printing. It is explanatory drawing which showed the method of selecting a maintenance operation | movement based on elapsed time and the frequency | count of a return in a maintenance operation | movement selection process.

Hereinafter, in order to clarify the contents of the present invention described above, examples will be described in the following order.
A. Device configuration:
B. Overview of printing behavior:
C. Maintenance operation selection processing of this embodiment:

A. Device configuration :
FIG. 1 is an explanatory diagram illustrating an ink jet printer 100 as a liquid ejecting apparatus according to the present embodiment. The illustrated inkjet printer 100 is JIS standard A1 or B1.
Large format printer (LF) that prints on so-called large format printing paper
P), but it may be a home printer that prints on a small printing paper such as an A4 size or a postcard size.

As shown in the drawing, the ink jet printer 100 roughly includes a main body case 110 and a paper feed unit 120 provided on the upper surface side of the main body case 110 and loaded with printing paper. 110 includes an ink ejecting unit 130 that ejects ink toward the printing paper, an ink maintenance unit 140 that manages the state of the ink, such as preventing ink drying, and the overall operation of the inkjet printer 100. A control unit 150 or the like for controlling is mounted.

The sheet feeding unit 120 includes a spindle unit 122, a cover unit 124, and the like. The spindle unit 122 is a shaft-like member that is rotatably supported at both ends, and is mounted with a roll-shaped printing paper (hereinafter referred to as roll paper). In addition, roll paper pressers that are slidable in the axial direction are provided at both ends of the spindle unit 122, and the roll paper loaded on the spindle unit 122 can be fixed so as not to move in the axial direction. It has become. Further, in order to avoid the roll paper mounted on the spindle part 122 from being damaged, the flip-up type cover part 1 is used.
24 is provided. When the roll paper is mounted on the spindle unit 122, the cover unit 12
4 is flipped up to expose the spindle unit 122, and roll paper is mounted on the spindle unit 122 taken out from the paper feeding unit 120. Then, after the spindle unit 122 loaded with roll paper is set in the paper feeding unit 120, the front end of the cover unit 124 is pushed down so that the cover unit 12 is pressed.
I ’ll close 4

The ink ejection unit 130 includes an ejection head 132 that ejects ink, an ink cartridge 134 that stores ink ejected by the ejection head 132, and an ink cartridge 134.
The ink tube 136 is configured to supply the ink inside to the ejection head 132. The ejection head 132 is provided with a plurality of fine ejection nozzles on the surface facing the printing paper. By ejecting ink from the ejection nozzles, it is possible to print characters or images on the printing paper. It has become. The surface of the portion where the plurality of ejection nozzles are formed on the side facing the printing paper of the ejection head 132 is called a “nozzle surface”. The ink jet printer 100 uses a plurality of types of ink such as cyan ink, magenta ink, yellow ink, and black ink. The ink cartridge 134, the ejection head 132, and the ink tube 136 are provided for each type of ink. However, in FIG. 1, only one ink type is displayed in order to avoid complicated illustration.

The ink maintenance unit 140 includes a cap 142 having a recess formed in the center, a waste ink tank 144 for storing ink discharged from the ejection head 132 due to deterioration in properties, and the like. The cap 142 can be brought into contact with or separated from the nozzle surface of the ejection head 132 by a drive mechanism (not shown), and is in contact with the nozzle surface while the image is not printed. ing. By doing so, it is possible to prevent the ejection nozzle from being sealed by the cap 142 and to dry the ink from the ejection nozzle. If the ink properties deteriorate due to, for example, ink drying, the ink is ejected from the ejection head 132 toward the recess of the cap 142, or the cap 142 is brought into contact with the nozzle surface of the ejection head 132. The suction pump (not shown) is operated to apply a negative pressure to the concave portion of the cap 142, whereby the deteriorated ink is sucked from the ejection nozzle. The ink discharged from the ejection head 132 in this way flows into the waste ink tank 144 through the tube and is stored.

An operation panel 112 for the user to operate the ink jet printer 100 is provided on the upper surface of the main body case 110. The operation panel 112 is equipped with a display screen configured by a liquid layer device, various operation buttons, and the like.
By operating the operation buttons while checking the display screen, the inkjet printer 100
Can be operated.

Although not shown in FIG. 1, a driving unit for reciprocating the ejection head 132 along the surface of the printing paper and a roll paper of the paper feeding unit 120 are wound inside the main body case 110. A paper feeding section for feeding out and feeding paper is also provided.

FIG. 2 is an explanatory diagram showing a rough configuration of a driving unit 160 for reciprocating the ejection head 132 and a paper feeding unit 170 for feeding roll paper. As shown in the figure, the drive unit 160 includes a guide rail 162 that guides the reciprocating movement of the ejection head 132, a drive belt 164 for reciprocating the ejection head 132 along the guide rail 162, and a drive belt 164. It is composed of a pair of pulleys 166 to be stretched, a drive motor 168 for driving the drive belt 164, and the like. At one place of the drive belt 164, the ejection head 1 is provided.
32 is fixed, and when the drive belt 164 is driven by rotating the drive motor 168 in the positive direction or the negative direction, the ejection head 132 reciprocates while being guided by the guide rail 162.

The paper feed unit 170 is provided in parallel with the guide rail 162 and has a long paper feed roller 172 having a length that crosses the roll paper in the width direction, and a paper feed motor 174 that rotates the paper feed roller 172. And a driven roller (not shown) provided along the roller 172. The roll paper loaded in the paper feeding unit 120 is fed to the paper feed roller 17.
2 is unwound and one end is inserted between the paper feed roller 172 and the driven roller. Then, the roll paper is pressed against the paper feed roller 172 with an appropriate force by the driven roller. When the paper feed motor 174 is rotated in this state, the roll paper is pulled out little by little as the paper feed roller 172 rotates. However, the paper is fed in the direction of the ejection head 132.

The operations of the drive motor 168 and the paper feed motor 174 are controlled by the control unit 150. The operation of ejecting ink by the ejection head 132 is also performed under the control of the control unit 150. Furthermore, as described above, the operation of moving the cap 142 to contact the nozzle surface of the ejection head 132, or the suction pump is operated while the cap 142 is in contact with the nozzle surface to suck out ink from the ejection nozzle. The operation is also performed under the control of the control unit 150. As described above, the control unit 150 is involved in almost all operations performed by the ink jet printer 100. When the start or end of printing, the ejection of ink into the cap 142, the suction of ink, or the like, they are performed. It is possible to accurately grasp the timing. Corresponding to this, the inkjet printer 10 of the present embodiment.
The zero control unit 150 is equipped with an elapsed time counter 152, and this elapsed time counter 15
2, the elapsed time since the last printing, ink ejection into the cap 142, ink suction, etc. is counted. Further, as described above, in this embodiment, since the ejection head 132 is reciprocated by switching the rotation direction of the drive motor 168 to the positive direction or the negative direction, the control unit 150 rotates the rotation direction of the drive motor 168. By detecting this change, it is possible to grasp the timing when the scanning direction of the ejection head 132 changes direction. Corresponding to this, the control unit 150 of the present embodiment is equipped with a return number counting unit 154 that counts the number of times the scanning direction of the ejection head 132 changes direction (hereinafter referred to as return number).

B. Overview of printing operation:
FIG. 3 is an explanatory diagram conceptually showing how the inkjet printer 100 of this embodiment prints an image while reciprocating the ejection head 132. 3 (a) and 3 (b)
), The ejection head 132 prints an image by ejecting ink toward a printing paper (roll paper) while reciprocating along the guide rail 162. The ejection head 132 and the ink cartridge 134 are connected by an ink tube 136 having a sufficient length, and the ink cartridge 1 is continuously applied by an ink pressurizing mechanism (not shown).
Ink is supplied from 34 to the ejection head 132. When the printing is finished, as shown in FIG. 3C, the ejection head 132 is moved to the position of the cap 142, and the cap 142 is pushed up by a drive mechanism (not shown) to be brought into contact with the nozzle surface of the ejection head 132. . In this way, since the ejection nozzle can be sealed with the cap 142, even when printing is not performed for a long time, the moisture or volatile component of the ink evaporates or volatilizes from the opening portion of the ejection nozzle, and the properties of the ink. Can be prevented from deteriorating.

Ink is produced by adding various components such as a coloring material for producing color, an additive for adjusting viscosity, and a surfactant to a solvent such as water or alcohol. Insoluble ingredients may be added. For example, pigments that are colorants with excellent weather resistance
Unlike dyes, they are not soluble in water or alcohol, so they exist in a suspended state in a solvent due to the action of a surfactant. Here, since the specific gravity of the pigment is greater than that of the solvent, if the ink is allowed to stand for a long time, the suspended pigment gradually settles due to the influence of gravity, and a portion having a high pigment concentration and a portion having a low pigment concentration. It will be possible. In the present specification, a component such as a pigment that exists in a suspended state without dissolving in an ink solvent is referred to as a “sedimentable component”. Ink containing a sedimenting component is referred to as “sinkable ink”, and the sedimentation of the sedimenting component in the ink is sometimes referred to as “ink sedimentation”.

When sedimentation ink is used in this way, not only the moisture and volatile components in the ink evaporate or volatilize and the ink dries, but also the sedimentation component settles in the ink. Properties deteriorate. The deterioration of the ink properties due to the sedimentation of the ink also occurs inside the ink tube 136.

FIG. 4 is an explanatory diagram conceptually showing how ink sedimentation occurs in the ink tube 136. For example, in a portion where the ink tube 136 is substantially horizontal, sedimentation occurs in a manner as shown in FIG. 4A as a result of the sedimentary component moving downward by gravity.
Further, the ink tube 136 always has a bent portion, but the bent portion causes ink sedimentation in a manner as shown in FIG. 4B. Thus, the ink tube 13
If ink sedimentation occurs at any of the locations 6, a portion where the concentration of the sedimentation component is high and a portion where the concentration is thin are generated, and ink cannot be ejected appropriately.

In order to avoid this, for example, prior to starting printing, for example, the ejection head 13
In a state where the cap 142 is in contact with the nozzle surface of the second nozzle, a fixed amount of ink is ejected from the ejection head 132.
Suction is performed from (cleaning). If all the ink settled in the ink tube 136 and the ejection head 132 is discharged in this way, the new ink supplied from the ink cartridge 134 is filled instead. Ink can be ejected.

However, since the ink sucked from the ejection head 132 is discharged without being used for printing, the ink is wasted. Therefore, in the ink jet printer 100 of the present embodiment, the following special processing is performed in order to reduce the amount of ink discharged due to ink sedimentation as much as possible. This process is a process for suppressing the ink discharge amount by paying attention to a phenomenon that occurs in the ink tube 136 when the ejection head 132 reciprocates during printing. So, before explaining the details of the process,
A phenomenon that occurs in the ink tube 136 during printing will be described.

FIG. 5 is an explanatory diagram showing how the ink tube 136 moves as the ejection head 132 reciprocates during printing. FIG. 5A shows the movement of the ink tube 136 when the ejection head 132 scans from the right end of the printing paper to the left, and FIG.
4 shows the movement of the ink tube 136 when the ejection head 132 scans the right end of the printing paper.

When the ejection head 132 scans from the right end of the printing paper to the left, the horizontal portion of the ink tube 136 (indicated as “Area A” in the drawing) located upstream of the ejection head 132 also moves in the traveling direction of the ejection head 132. To do. As a result, as shown in FIG. 5A, the bent portion of the ink tube 136 located upstream of the region A (shown as “region B” in the drawing)
As it is pushed down, the bend is gradually released, and it changes to a substantially horizontal state.

When the ejection head 132 further advances to the left and reaches the left end of the printing paper, the scanning direction is switched from the left to the right. Then, when scanning rightward as it is, FIG.
The ejection head 132 returns to the position). In the meantime, the region B of the ink tube 136 is maintained in the substantially horizontal state described above. However, when the ejection head 132 further moves rightward from the state of FIG. 5A, the horizontal portion (region A) of the ink tube 136 is maintained. ) Moves to the right as it is pulled by the ejection head 132. As a result, as shown in FIG.
The region B is moved by the region A so as to wind up substantially obliquely upward.

During printing by the ink jet printer 100, each time the ejection head 132 reciprocates the printing paper, the ink tube 13 is bent at the bent portion (region B) of the ink tube 136.
The operation of changing the direction so that 6 is performed is frequently repeated. As a result, the ink tube 1
In 36, a sedimentation component (a pigment or the like) is stirred.

Further, also in the region A of the ink tube 136, the sedimentary component is agitated by the ejection head 132 scanning the printing paper. FIG. 6 is an explanatory diagram showing how the sedimentary component is agitated in the horizontal portion (region A) of the ink tube 136. In order to avoid complication of the figure, in FIG. 6, the amount of the sedimentation component in the ink tube 136 is shown to be small.

As described above, when ink sedimentation occurs in the region A of the ink tube 136, the sedimenting component suspended in the ink solvent settles downward due to gravity (see FIG. 4A).
When the ejection head 132 scans in the right direction in the state where the ink has settled in the area A, the area A of the ink tube 136 is also moved in the right direction. Therefore, the ink solvent in the area A is also settled. Also moves to the right together with the ink tube 136. At this stage, the ink solvent and the sedimenting component are moving to the right at the same speed, so that the sedimenting component is still settled (see FIG. 6A). From this state, when the ejection head 132 suddenly stops to switch the scanning direction to the left, the ink tube 136 that has moved to the right until now also suddenly stops. Here, since the sedimentation component is heavier than the ink solvent, the sedimentation component does not stop even if the ink solvent is stopped by stopping the ink tube 136, and tries to move in the solvent. As a result, as shown in FIG. 6B, the settled ink components move so as to roll up in the solvent, and the ink sedimentation is alleviated. As described above, when the ejection head 132 reciprocates, the ink sedimentation is alleviated every time the ejection head changes direction in the ink in the area A, as in the area B.

In the present embodiment, the following processing is performed in order to suppress the amount of ink discharged by ink settling as much as possible by considering the stirring effect of the settling component accompanying the reciprocation of the ejection head 132 described above. It is carried out.

C. Maintenance operation selection processing of this embodiment:
FIG. 7 is a flowchart showing the maintenance operation selection process of this embodiment. The maintenance operation selection process of the present embodiment is a process that is executed before the inkjet printer 100 starts printing, and is executed by the control unit 150 (see FIG. 2) that controls the operation of the entire inkjet printer 100. Is done.

When the maintenance operation selection process is started, first, the time elapsed after the previous maintenance operation is executed (hereinafter referred to as elapsed time) is acquired (step S100). As described above, the controller 150 of the present embodiment is provided with the elapsed time timer 152 that counts the elapsed time since the last printing, ink suction, or the like (see FIG. 2). . In step S102, the elapsed time from the previous maintenance operation is acquired by referring to the time counted by the elapsed time counting unit 152 (step S100).

When the elapsed time since the previous maintenance operation was acquired in this way (step S1)
00), and then the number of times the scanning direction of the ejection head 132 has changed direction within the elapsed time (ie, the number of returns) is acquired (step S102). As described above, since the control unit 150 is provided with the return number counting unit 154 that counts the number of return of the ejection head 132, in step S102, the return number within the elapsed time acquired earlier is referred to. The number of returns within the elapsed time is acquired (step S102). Here, the maintenance operation selection process according to the present embodiment acquires not only the elapsed time from the previous maintenance operation but also the number of returns within the elapsed time for the following reason.

Usually, ink sedimentation proceeds with time. Therefore, it is possible to estimate the degree of sedimentation in the ink tube 136 to some extent by acquiring the elapsed time since the previous maintenance operation was performed. For example, if the elapsed time from the previous maintenance operation is long, it is estimated that the ink has settled in the ink tube 136, and if the elapsed time is short, the ink is presumed to be slight.

On the other hand, when printing has been performed since the previous maintenance operation was performed, the sedimentary component in the ink tube 136 is agitated each time the scanning direction of the ejection head 132 changes direction. Therefore, as the number of times the ejection head 132 changes the scanning direction within the elapsed time (that is, the number of returns) increases, the effect of stirring the sedimentation component increases, and the ink settling in the ink tube 136 is suppressed. Conceivable. Therefore, in consideration of the stirring effect of these sedimentation properties, in order to more accurately grasp the ink sedimentation state, not only the elapsed time from the previous maintenance operation but also the ejection head generated during printing The number of returns 132 is also acquired.

As described above, when the elapsed time from the previous maintenance operation and the number of returns within the elapsed time are acquired (step S100, step S102), the maintenance to be executed this time is based on the elapsed time and the number of returns. Select an action (step S1
04).

FIG. 8 is an explanatory diagram showing a method of selecting a maintenance operation based on the elapsed time and the number of returns. In FIG. 8, the horizontal axis indicates the elapsed time, and the vertical axis indicates the number of returns. Further, FIG. 8 shows four areas distinguished according to the length of the elapsed time and the number of returns, and different maintenance operations are set in each area.

First, the maintenance operation selected when the elapsed time from the previous maintenance operation is long and the number of returns is small (corresponding to the area labeled “HC” in the lower right of FIG. 8) will be described. In this case, it is considered that the ink settling in the ink tube 136 is proceeding because a long time has passed. Further, since the number of returns of the ejection head 132 is small, the above-described stirring effect of the sedimentation component can hardly be expected. Therefore, an operation (cleaning) for sucking ink from the ejection head 132 is selected as the maintenance operation. Particularly in this case, since the degree of ink settling in the ink tube 136 is determined to be the most serious, HC (heavy cleaning), which is the most powerful maintenance operation, is selected as the maintenance operation.

Next, the case where the elapsed time from the previous maintenance operation is long but the number of returns is large (corresponding to the area labeled “LC” in the upper right of FIG. 8) will be described. Although it is considered that the ink settling in the ink tube 136 is proceeding, the above-described stirring effect of the settling component can be expected because the ejection head 132 is returned many times. Therefore, it is determined that the ink sedimentation is suppressed to some extent as compared with the case where the elapsed time is long and the number of returns is small.
LC is a maintenance operation that requires less ink than light cleaning)
Select (Light cleaning).

Further, when the elapsed time since the previous maintenance operation is short and the number of returns is small (corresponding to the area labeled “HF” in the upper right of FIG. 8), only a short time has passed, so the inside of the ink tube 136 However, since the number of returns of the ejection head 132 is small, the stirring effect of the sediment component cannot be expected. Therefore,
The maintenance operation is a light maintenance operation that requires less ink discharge than the cleaning described above, and selects an operation (flushing) of ejecting ink from the ejection head 132. However, considering that the stirring effect of the sediment component cannot be expected, strong HF (heavy flushing) is selected as the flushing operation.

Finally, if the elapsed time from the previous maintenance operation is short and the number of returns is large (corresponding to the area labeled “LF” in the upper right of FIG. 8), only a short time has passed, so the ink tube 136 has passed. It is considered that the ink sedimentation has not progressed so much, and further, since the number of returns of the ejection head 132 is large, the stirring effect of the sedimentation component can be expected. Accordingly, in this case, it is determined that the degree of ink settling is lightest, so LF (light flushing), which is the lightest maintenance operation with the smallest ink discharge amount, is selected as the maintenance operation.

Thus, when one of the four maintenance operations (HC, LC, HF, LF) described above is selected based on the elapsed time since the previous maintenance operation and the number of returns within the elapsed time (step S104). Then, an instruction is issued to the suction pump 146 or the ejection head 132 so as to execute the selected maintenance operation (step S106), and then the maintenance operation selection process is terminated.

As described above, in the maintenance operation selection process of the present embodiment, the ejection head 132 is printed during printing.
In consideration of the ink stirring effect due to the change in direction of the ink, it is possible to accurately determine the degree of ink settling in the ink tube 136, so that an appropriate maintenance operation is selected according to the degree of ink settling. Can do. Therefore, the ejection head 13 is frequently used during printing.
2 repeats the reciprocating motion, so that a large amount of ink is not wastefully discharged until the ink tube 136 has hardly settled. As a result, the amount of ink discharged during the maintenance operation can be reduced as much as possible.

In the maintenance operation selection process of the present embodiment described above, the number of returns of the ejection head 132 is counted, not the time during which printing is performed. For this reason, for example, when printing on printing paper with a narrow paper width, the number of returns is large for the printing time, and therefore a large stirring effect can be expected, or conversely, the paper width is wide for the printing time. Even when the number of returns is small and therefore the stirring effect cannot be expected so much, it is possible to accurately grasp the degree of ink settling.

As mentioned above, although the Example of this invention was described, this invention is not limited above,
The present invention can be implemented in various modes without departing from the gist thereof. For example, in an ink jet printer in which an ink cartridge is directly mounted on an ejection head, it is considered that the ink settling portion (here, the ink cartridge) is shaken each time the ejection head changes direction, thereby suppressing ink settling. Therefore, as in the above-described embodiment, not only an ink jet printer in which an ink tube is provided between an ejection head and an ink cartridge, but an ink jet in which no ink tube is provided by mounting the ink cartridge on the ejection head. The present invention can also be applied to a printer.

100 ... inkjet printer, 132 ... jetting head,
134: Ink cartridge, 136: Ink tube,
142 ... cap, 146 ... suction pump,
150 ... control unit, 152 ... elapsed time timing unit,
154 ... Return count section

Claims (3)

A liquid ejecting apparatus that ejects liquid from the ejection nozzle while reciprocating the ejection head provided with the ejection nozzle,
A liquid container containing a liquid containing a sedimentary component;
A liquid passage for guiding the liquid in the liquid container to the ejection head;
In order to avoid the sedimentation component contained in the liquid from settling in the ejection head or the liquid passage, the liquid is ejected from the ejection nozzle at a predetermined location on the path along which the ejection head reciprocates. Liquid discharging means for discharging;
Time measuring means for measuring the elapsed time since the liquid discharging means discharged the liquid at the predetermined location;
A counting means for counting the number of times of turning, which is the number of times of turning when the jet head reciprocates after the liquid discharging means discharges the liquid at the predetermined location, and
The liquid ejecting apparatus is a liquid ejecting apparatus that ejects the liquid in consideration of the elapsed time and the number of times of turning when the liquid is ejected at the predetermined location. The liquid ejecting apparatus according to claim 1,
A discharge operation storage means for storing a plurality of discharge operations with different liquid discharge amounts as a discharge operation in which the liquid discharge means discharges the liquid at the predetermined location;
The liquid discharging means is means for discharging liquid in accordance with the discharging operation selected from the plurality of discharging operations stored in the discharging operation storing means based on the elapsed time and the number of times of turning. A liquid ejecting device. The liquid ejecting apparatus according to claim 1 or 2,
A recess for receiving the liquid discharged from the ejection nozzle is formed, and a liquid receiving portion that forms a closed space around the ejection nozzle by being in contact with the ejection head;
A suction pump connected to the recess of the liquid receiving part,
The liquid ejecting apparatus is a liquid ejecting apparatus that ejects liquid from the ejection nozzle by operating the suction pump in a state where the liquid receiving portion is in contact with the ejection head.

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