JP2009012352A - Liquid jet apparatus and liquid injection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid jet apparatus and a liquid injection method which can prolong the lifetime of a head unit by preventing a nozzle opening group constituting a head unit from being used in its partial region. <P>SOLUTION: A plurality of head units 36, 37, 38 and 39 having different corresponding paper width use printers juxtaposed by justifying the ends at any one of the right and left ends in the paper feed direction and by shifting the position in the paper feed direction. The nozzle opening group is prevented from being used in its partial region by using the head units of low degree of use for printing depending on the width of a sheet of paper to be used thus prolonging the lifetime of the head unit. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ink jet type liquid ejecting apparatus and a liquid ejecting method in which a line head matched to the width size of a recording medium is mounted as an ejecting head.

  Inkjet printers eject ink droplets from the nozzles mounted on the print head toward the printing paper to print images, etc., and can achieve high-definition printing at low cost. It is used in various devices such as printers, copiers, and facsimiles.

Such an ink jet printing apparatus can be roughly classified into a serial type and a line head type depending on the type of the print head.
In the serial type, a print head in which nozzles for ejecting ink droplets are arranged in a width smaller than the width of the paper is mounted on a carriage that can reciprocate in the width direction of the paper, and the paper is orthogonal to the conveyance direction of the printing paper. The print head is moved in the width direction to form an image for the paper width.
The line head type uses a line head in which nozzles for ejecting ink droplets are arranged in the same width as the paper width, and forms an image for the paper width at a time without moving the line head.

  Compared to the serial type, the line head type does not require the print head to move in the width direction of the printing paper, and so-called one-pass printing is possible, enabling high-speed printing. This eliminates the need for a carriage on which the motor is mounted and a drive system for moving the same, so that the apparatus can be reduced in size and weight, and has various advantages such as greatly improved quietness.

Incidentally, a normal printing apparatus is compatible with a plurality of types of printing paper having different sizes. In the case of the above-mentioned line head type printing device, the length of the head unit (number of nozzles) is set based on the maximum paper width, and when printing on paper with a small width, the paper size is selected. Only the nozzles in a part of the width area on the line head are used according to the signal and the print area instruction signal.
That is, when printing on narrow paper, only the nozzles in the area corresponding to printing on the narrow paper among the nozzles on one line head are used, but the nozzles in other areas are not used. The nozzles in the area corresponding to the printing on the narrow paper are used earlier than the nozzles in the other areas.
As a result, the degree of use of the nozzles assigned to printing on the narrow paper becomes more uneven. For example, the nozzles in the central printing area corresponding to printing on the narrow paper are earlier than the nozzles in the printing areas on both sides. Since the end of the service life is reached and the nozzle in the center printing area reaches the end of the service life, it is necessary to replace the entire line head.

Therefore, the following two techniques have been proposed in order to eliminate the drawbacks of such a line head type printing apparatus.
One is equipped with a unit moving means for moving the line head, which should originally be fixedly mounted, in the paper width direction. When printing on a narrow paper, the unit moving means prints on the narrow paper. In this technique, nozzles on the line head are moved to a position so that the nozzles on the line head are less used (for example, Patent Document 1 below).
The other is that the feeding position of the narrow paper can be changed in the width direction in various ways, so that the usage of the nozzles on the line head is not biased by the printing of the narrow paper. At the time of printing, this is a technique for adjusting the paper feed position in the width direction so as to eliminate the bias due to the degree of use until then (for example, Patent Document 2 below).

JP 2005-297510 A JP 2000-334935 A

  However, the above-mentioned two correspondences can improve the effect to some extent in terms of reducing the deviation of the usage degree of the nozzles due to the printing on the narrow paper, but it is used for almost all the nozzles of the line head. The purpose of equalizing the degree and extending the life of the entire line head was not satisfactory.

  For example, when the frequency of printing on an intermediate width sheet whose width dimension is 1/2 or more of the maximum sheet width is high, the intermediate width sheet can be used regardless of whether the line head is moved or the paper feed position is moved. The nozzles on the line head allocated for printing the area corresponding to a width exceeding 1/2 of the maximum paper width above will continue to be used without break. For this reason, it is impossible to eliminate the uneven usage of some nozzles, and in the end, it is not possible to avoid the problem that the entire line head needs to be replaced because some nozzles reach the end of their service life early. It was.

  In addition, in the printing apparatus and printing method in which the line head corresponding to the maximum sheet width is moved in the sheet width direction, there is a problem that the apparatus is enlarged due to the increase in the apparatus width.

  Accordingly, an object of the present invention is to solve the above-described problem, and the nozzle openings in other regions are not used because the degree of use is biased to the nozzle opening groups in a part of the nozzle openings constituting the head unit. The head unit has a long service life by preventing the inconvenience of reaching the end of its life, even though its usage is low and still has a sufficient life, and by equalizing the usage of each nozzle opening. Provided are a liquid ejecting apparatus and a liquid ejecting method. It is another object of the present invention to provide a liquid ejecting apparatus and a liquid ejecting method that do not increase the size of the apparatus due to an increase in the apparatus width.

  A liquid ejecting apparatus according to the present invention that can solve the above-described problem is a liquid ejecting apparatus that ejects liquid onto a recording medium from a nozzle opening, and a plurality of head units corresponding to the width of the recording medium include: It is characterized by being arranged in parallel in the conveyance direction of the recording medium.

According to the liquid ejecting apparatus having this configuration, at the time of liquid ejecting, it is basically possible to select and use a head unit whose maximum ejection width matches the width of the recording medium to be ejected. Thereby, for example, it is possible to eliminate a useless operation in which some nozzle openings on the upper size head unit having a jetting area with a large width of the corresponding recording medium are not used and operated. Therefore, it is possible to prevent the occurrence of the problem of uneven usage of the nozzle openings on one head unit.
Accordingly, since the degree of use is biased toward the nozzle opening groups in a part of the nozzle opening groups constituting one head unit, the nozzle openings in other areas are less used and still have a sufficient life. Nevertheless, it is possible to prevent the inconvenience that the head unit reaches the end of its life. Therefore, the life of the head unit can be extended by equalizing the degree of use of each nozzle opening. In addition, since the head unit does not need to move in the width direction of the recording medium, the size of the apparatus does not increase due to an increase in the apparatus width.
The head unit can be arranged at either the left or right end so that liquid is ejected at either the left or right end, or the head unit can be disposed at the central area and liquid can be ejected at the central area. It is also possible to dispose liquid at different positions by disposing the liquid at different positions.

Further, the recording means for storing the cumulative use count for each head unit corresponding to the width of the recording medium is compared with the cumulative use count for each head unit stored in the recording means, so that the cumulative use count is small. It is preferable to have a configuration including switching means for switching to the head unit.
According to this configuration, when there are a plurality of candidates as head units capable of ejecting liquid on a desired recording medium, the variation in the degree of use of each head unit is grasped from the cumulative number of uses stored for each head unit. It becomes possible. From these candidates, it is possible to preferentially select a head unit with a small cumulative number of times of use. As a result, it is possible to eliminate the uneven usage of each head unit, and even if the frequency of liquid ejection to a part of the recording medium width is high, only the head unit corresponding to the recording medium width is used continuously. It is possible to prevent the occurrence of a problem that the service life is exhausted earlier than the head unit.

Further, the recording means for storing the cumulative discharge amount for each head unit corresponding to the width of the recording medium, and the head having a small discharge amount by comparing the cumulative discharge amount for each head unit stored in the recording means It is preferable to have a configuration including switching means for switching to a unit.
According to this configuration, the life of the nozzle openings constituting each head unit is affected not only by the number of ink droplet ejections but also the amount of ink droplets ejected. It can be managed by recording the quantity. This makes it possible to grasp the variation in the degree of use of each head unit from the cumulative discharge amount stored for each head unit, and by using the head unit with a small cumulative discharge amount with priority, The uneven usage of the head unit can be eliminated.

  The liquid ejecting method according to the present invention that can solve the above-described problem is a liquid ejecting method that ejects liquid onto a recording medium from a nozzle opening, and the width of the recording medium is automatically recognized by a sensor, or A head unit capable of being ejected onto the recording medium is selected from a plurality of head units that are recognized by the guide position of the transport tray and correspond to the width of the recording medium.

According to the liquid ejecting method of this configuration, a plurality of head units can be used properly without bothering the user, and the head unit corresponding to the width of the recording medium to be ejected can be selected and used. it can. Thereby, for example, it is possible to eliminate useless usage such as operating some nozzle openings on a head unit having a jetting area having a large width of the corresponding recording medium in an unused state. Therefore, it is possible to prevent the occurrence of the problem of uneven usage of the nozzle openings on one head unit.
Accordingly, since the degree of use is biased toward the nozzle opening groups in a part of the nozzle opening groups constituting one head unit, the nozzle openings in other areas are less used and still have a sufficient life. Nevertheless, it is possible to prevent the inconvenience that the head unit reaches the end of its life. Therefore, the life of the head unit can be extended by equalizing the degree of use of each nozzle opening. In addition, since the head unit does not need to move in the width direction of the recording medium, the size of the apparatus does not increase due to an increase in the apparatus width.

In addition, the cumulative use count is stored in the recording means for each head unit, and during the ejection process, the cumulative use count of each head unit is compared, and a head unit with a low cumulative usage count is selected and ejected. A configuration is preferable.
According to this configuration, in addition to the functions and effects of the above-described liquid ejecting method, the following functions and effects can be obtained.
In other words, when there are a plurality of candidates as head units capable of liquid jetting on a desired recording medium, the head unit used by each head unit is selected by giving priority to the head unit with a small cumulative number of times of use. The degree of bias can be eliminated. As a result, even when the liquid ejection frequency of some recording medium widths is high, only the head unit corresponding to the recording medium width is continuously used, and the occurrence of the problem that the life is exhausted earlier than other head units is prevented. can do.

Further, as the cumulative use count recorded for each head unit, an average value obtained by dividing the sum of the cumulative use counts for each nozzle opening constituting the head unit by the nozzle aperture count of the head unit is used. It is preferable that
According to this configuration, even when there is a variation in the cumulative number of uses of each nozzle opening within each head unit, the degree of use of each head unit can be comprehensively evaluated for each head unit. The selection of fewer head units can be simplified.

Also, the cumulative discharge amount is stored in the recording means for each head unit, and during the ejection process, the cumulative ejection amount of each head unit is compared, and a head unit with a small cumulative ejection amount is selected and ejected. A configuration is preferable.
According to this configuration, in addition to the functions and effects of the above-described liquid ejecting method, the following functions and effects can be obtained.
That is, when there are a plurality of candidates as head units capable of ejecting liquid on a desired recording medium, a head unit with a small cumulative discharge amount can be selected preferentially from those candidates. As a result, it is possible to eliminate the uneven usage of each head unit, and even when the liquid ejection frequency of a part of the recording medium width is high, only the head unit corresponding to the recording medium width is continuously used and other heads are used. It is possible to prevent the occurrence of a problem that the lifetime is exhausted earlier than the unit.

Further, as the cumulative discharge amount to be recorded for each head unit, an average value obtained by dividing the sum of the cumulative discharge amounts for the respective nozzle openings constituting the head unit by the number of nozzle openings of the head unit is used. It is preferable that
According to this configuration, even when there is a variation in the cumulative discharge amount of each nozzle opening within each head unit, the use degree of each head unit can be comprehensively evaluated for each head unit. The selection of fewer head units can be simplified.

Hereinafter, preferred embodiments of a liquid ejecting apparatus and a liquid ejecting method according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic side view of a printing apparatus which is a first embodiment of a liquid ejecting apparatus according to the present invention, and FIG. 2 is an explanatory diagram showing the relationship between the configuration of a print head of the printing apparatus of FIG. FIG. 3 is a flowchart showing a procedure of a printing method performed by the printing apparatus shown in FIG.

  The printing apparatus 10 according to the present embodiment includes a paper tray 13 that stores printing paper (recording paper) S that is a recording medium, an image recording unit 16 that includes an inkjet print head 11, and a housing 12. A paper supply unit 15 that feeds the print sheets S in the paper tray 13 one by one to the front image recording unit 16 side, and a discharge port for the print sheets S fed by the paper supply unit 15 via the image recording unit 16 18 is provided with a transport unit 14 to be sent to 18, and a control unit 17 that performs drive control of these units.

  The housing 12 is formed in a rectangular parallelepiped box shape. A discharge port 18 for discharging the printing paper S after the printing process is provided on the wall surface in the insertion direction of the paper tray 13. Further, a tray attachment / detachment opening 19 for attaching / detaching the paper tray 13 is provided on the wall surface behind the paper tray 13 in the insertion direction.

  The transport unit 14 is provided between a paper feed guide 20 serving as a guide surface for feeding the printing paper S between the front end of the paper tray 13 and the discharge port 18, and between the paper feed guide 20 and the front end of the paper tray 13. A first paper feed roller pair 21 that sandwiches the print paper S fed from the paper tray 13 by a pair of rollers and feeds it onto the paper feed guide 20. A second paper feed roller pair 22 is provided between the paper feed guide 20 and the discharge port 18 and sandwiches the printing paper S on the paper feed guide 20 between a pair of rollers and feeds the print paper S to the discharge port 18. In addition, pulleys 23 and 24 for driving these paper feed roller pairs 21 and 22, a transport unit drive motor 25 disposed below the paper feed guide 20, and a driving force of the transport unit drive motor 25 is applied to the pulleys 23 and 24. Belts 26 and 27 for transmitting to 24.

  The paper feed guide 20 is formed in a flat plate shape and serves as a transport surface for transporting the print paper S. At the same time, the paper feed guide 20 is disposed below the print head 11 with a predetermined gap and holds the print paper S during the printing process. Providing a plane.

  The paper supply unit 15 is disposed above the front end of the paper tray 13. The paper supply unit 15 is in contact with the print paper S in the paper tray 13 and supplies the print paper S to the first paper feed roller pair 21 one by one, and a drive source that rotationally drives the supply roller 28 And a gear 29 that transmits the output of the supply motor 30 to the supply roller 28.

  The supply roller 28 is formed in a substantially semi-cylindrical shape, and is provided in the vicinity of the first paper feed roller pair 21. The supply motor 30 is disposed above the supply roller 28.

  The paper tray 13 is formed in a box shape that can accommodate a large number (for example, several hundreds) of printing paper S in a stacked state, and is detachably mounted in a space extending from the lower side of the paper supply unit 15 to the tray attachment / detachment opening 19. Has been. The paper tray 13 is provided with a paper support 32 biased upward by a spring 31 at a position near the front end of the bottom surface, and the printing paper accommodated by the elastic displacement of the paper support 32 upward. The uppermost S is brought into contact with the supply roller 28.

The printing apparatus 10 of the present embodiment handles various sizes such as A3, B4, A4, B5, postcards, and photo L plates as the printing paper S.
The width of the paper tray 13 is set in accordance with the A3 size, which is the maximum paper width, so that any of these various sizes of paper can be accommodated. As shown in FIG. 2, a guide (not shown) is provided in the paper tray 13 to position the accommodated sheets of each size toward the right end. In FIG. 2, the A3 size printing paper S1, the B4 size printing paper S2, the A4 size printing paper S3, and the postcard size printing paper S4 are vertically oriented toward the right edge of the paper tray 13 and aligned. Show.
In the present embodiment, the case where the head unit is arranged at the right end will be described as an example. However, the left end alignment and the center alignment are possible, and printing is performed at different positions by arranging the paper units at different positions for each paper width. Is also possible. Furthermore, the present invention can be applied to a line head in which a plurality of serial heads are arranged in parallel or in a staggered manner.

The control unit 17 is an electronic control unit (ECU) incorporating various electronic components, and is disposed above the paper tray 13.
The control unit 17 is electrically connected to the print head 11, the conveyance unit drive motor 25, and the supply motor 30, and controls these operations. The control unit 17 incorporates a head unit controller 33 that mainly controls the operation of the print head 11.

As shown in FIG. 2, the print head 11 is provided with four head units 36, 37, 38, 39 corresponding to different paper widths in a head case 35.
The head unit 36 has a plurality of nozzle openings arranged in the paper width direction corresponding to the paper width when the A3 size printing paper S1 is vertically fed, and has a paper width smaller than the short side of the A3 size (for example, , B4, A4 size, etc.) can also be selected.
The head unit 37 has a large number of nozzle openings arranged in the paper width direction corresponding to the paper width when the B4 size printing paper S2 is vertically fed, and has a paper width smaller than the short side of the B4 size (for example, , A4, B5 size, etc.) can also be selected.
The head unit 38 has a large number of nozzle openings arranged in the paper width direction corresponding to the paper width when the A4 size printing paper S3 is vertically fed, and has a paper width smaller than the short side of the A4 size (for example, , B5, postcard size, etc.) can also be selected.
The head unit 39 has a large number of nozzle openings arranged in the paper width direction corresponding to the paper width when the postcard-size printing paper S4 is vertically fed, and has a paper width smaller than the short side of the postcard size (for example, It can also be selected when printing on the L size of a photograph).

  These head units 36, 37, 38, 39 are aligned at the right end position, which is the positioning end of the paper in the paper tray 13, and shifted in the paper feeding direction (arrow A direction in FIG. 2). It is installed.

The head units 36, 37, 38, and 39 are for color printing, and are arranged in nozzle rows for four colors, with their positions shifted in the paper feeding direction.
In each head unit 36, 37, 38, 39, the nozzle rows 36 a, 37 a, 38 a, 39 a have nozzle openings 41 for ejecting cyan (C) ink arranged at a constant pitch on the corresponding paper width. It is. The nozzle rows 36b, 37b, 38b, and 39b are configured such that nozzle openings 42 that eject magenta (M) color ink are arranged at a constant pitch in the corresponding paper width. The nozzle rows 36c, 37c, 38c, and 39c are configured such that nozzle openings 43 that eject yellow (Y) ink are arranged at a constant pitch in the corresponding paper width. The nozzle rows 36d, 37d, 38d, and 39d are nozzle openings 44 that eject black (K) ink and are arranged at a constant pitch in the corresponding paper width.

  Each head unit 36, 37, 38, 39 is full-colored by superimposing ink droplets ejected from the nozzle openings 41 to 44 of the respective colors in the respective units on the printing paper S and adjusting the application amount of each color to be superimposed. Realize printing.

  In the case of this embodiment, the head unit controller 33 that controls the operation of each head unit 36, 37, 38, 39 has a cumulative number of times of use for each head unit 36, 37, 38, 39 with a different corresponding paper width. And a switching means 53 for comparing the cumulative number of times of use for each head unit 36, 37, 38, 39 stored in the storage means 51 and switching to a head unit with a small cumulative number of times of use, It has.

  In the case of the present embodiment, the storage means 51 records, for each head unit 36, 37, 38, 39, the cumulative number of times used for each nozzle opening constituting each unit, and further, each head unit. Each time, an average value is recorded by dividing the sum of the cumulative number of times of use for each nozzle opening constituting the head unit by the number of nozzle openings of the head unit.

  Next, a printing method that is performed by the operation control by the head unit controller 33 of the control unit 17 in the printing apparatus 10 will be described.

  The head unit controller 33 is used in accordance with the procedure shown in FIG. 3 when print data (consisting of a print command and image information to be printed) is input from an input device (for example, a computer) (not shown). The head unit is selected and the printing process is performed.

  That is, first, when input of print data is received (step S101), the print size is recognized from the paper size information in the print data (step S102), and the paper width of the print paper S stored in the paper tray 13 is determined. Is recognized by automatic recognition by a sensor (not shown) provided in the housing 12 or by the guide position of the paper tray 13 (step S103). Then, a head unit capable of printing on the paper is selected from among the plurality of head units 36, 37, 38, and 39 having different paper widths corresponding to the print head 11 (step S104).

  In the processing of step S104, for example, when the printing paper S loaded in the paper tray 13 is A4 size printing paper S3, the head unit corresponding to the printing paper S3 having a larger paper width is included. The head units 36, 37, and 38 shown in FIG. 2 are selected as usable unit candidates.

  Next, the cumulative number of times used for each head unit 36, 37, 38, 39 until the previous printing process stored in the storage means 51 is compared (step S105), and the candidate selected in step S104 is selected. Then, the head unit having the smallest cumulative number of times of use is selected and the head to be used is determined (step S106). In step S105, the cumulative number of times of use for each head unit 36, 37, 38, 39 is compared by dividing the total number of times of cumulative use for each nozzle opening constituting each head unit by the number of nozzle openings of the head unit. The average value is used.

  In the process of determining the head to be used in step S106, a head unit that matches the paper width is not always selected.

  For example, when the printing paper S supplied from the paper tray 13 is A4 size printing paper S3, in step S104, the head unit 36 for A3 size printing, the head unit 37 for B4 size printing, and for A4 size printing are used. The three types of head units of the head unit 38 are candidates for use. If the cumulative number of times the A3 size printing head unit 36 is smaller than the other two head units 37 and 38 in terms of the average cumulative number of times used by each head unit, the head unit for A3 size printing 36 is determined as a working head.

  Next, print data (image data) is output to the head unit determined in step S106 (step S107), and paper is fed from the paper tray 13 to the image recording unit 16 in conjunction therewith. Then, printing is executed by ejecting ink droplets from the nozzle openings on the head unit in synchronization with the feeding speed of the paper feed (step S108). Then, the nozzle opening used for ejecting the ink droplet is counted for the number of times of use, and the cumulative number of times of use stored in the storage means 51 is updated (step S109).

In the printing process by the printing apparatus 10 described above, the paper width is recognized by the automatic recognition by the sensor or the guide position of the paper tray 13 during the printing process, and a plurality of head units 36, 37, A head unit capable of printing on the paper is selected from 38 and 39.
Accordingly, the plurality of head units 36, 37, 38, 39 can be used properly without bothering the user.

  Basically, by selecting and using a head unit whose maximum print width matches the paper width to be printed, by selecting and using the corresponding head unit, for example, the corresponding paper width can be increased. Eliminating the use of some nozzle openings on the upper size head unit that has a large print area without using it, and uneven usage between nozzles on one head unit It is possible to prevent the occurrence of a problem of progress.

As a result, the usage degree is biased toward the nozzle opening group in a part of the nozzle opening group constituting one head unit, and the nozzle opening in the other area is less used and still has a sufficient life. In spite of this, it is possible to prevent the inconvenience of reaching the end of the life of the head unit, and it is possible to extend the life of the head unit by equalizing the degree of use of each nozzle opening. In addition, since the head unit does not need to be moved in the paper width direction, the size of the apparatus is not increased due to an increase in the apparatus width.
In the present embodiment, the arrangement position of each head unit 37, 38, 39 has been described as an example of right-alignment. However, left-alignment and center-alignment are possible, and each head unit 37, 38, 39 is disposed at a different position for each sheet width. It is also possible to print at different positions.

  Further, in the printing apparatus 10 according to the above-described embodiment, the storage unit 51 that stores the cumulative number of times of use for each head unit 36, 37, 38, 39 having a different corresponding paper width, and each head stored in the storage unit 51. And a switching means 53 that compares the cumulative number of times used for each of the units 36, 37, 38, and 39 and switches to a head unit that has a low cumulative number of times of use. Then, at the time of the printing process, the cumulative use frequency of each head unit is compared between the available head unit candidates, and a head unit with a low cumulative usage frequency is selected and printed.

  Therefore, when there are a plurality of candidates as head units capable of printing on the printing target paper, the degree of use between the head units is determined from the accumulated use count stored for each head unit 36, 37, 38, 39. The variation can be grasped, and a head unit with a small cumulative number of times of use is preferentially selected from these candidates. Accordingly, it is possible to eliminate the uneven use of each head unit, and even when the printing frequency of a part of the paper width (for example, A4 size printing paper S3) is high, the head unit corresponding to the paper width (for example, Thus, it is possible to prevent the occurrence of a problem that only the head unit 38) is continuously used and its life is exhausted earlier than other head units.

Further, in the printing apparatus 10 of the present embodiment, as the cumulative number of times used for recording for each head unit, the sum of the cumulative number of times used for each nozzle opening constituting the head unit is expressed as the number of nozzles of the head unit. Use the divided average.
For this reason, even if there is a variation in the cumulative number of times the individual nozzle openings are used within each head unit, it is possible to comprehensively evaluate the degree of use of each head unit for each head unit. The selection process can be simplified.

In the printing apparatus 10, each head unit 36, 37, 38, 39 is fixedly equipped with its end position aligned with the right end serving as a reference position during paper feeding, as shown in FIG. It was. However, other than the head unit 36 having the maximum print width, the position may be freely changed (moved) in the print width direction within the print area of the head unit 36 when printing is not performed.
In this way, when the head unit having a small print area is moved within the range of the head unit 36 having the maximum print width, the apparatus width is not increased, and the degree of freedom in selecting the head unit to be used is further increased. Thus, it is possible to further thoroughly prevent the uneven usage of each head unit.

  In the printing apparatus and the printing method according to the present invention, the method of managing the degree of use in each head unit is not limited to the method of recording the cumulative number of times of use of each nozzle opening shown in the above embodiment.

  For example, instead of the storage unit 51 shown in the above embodiment, the head unit control unit 33 includes a storage unit that stores the accumulated discharge amount for each head unit 36, 37, 38, 39 having a different paper width. Equipped. Further, instead of the switching means 53 shown in the above embodiment, the cumulative discharge amount for each head unit 36, 37, 38, 39 stored in the storage means is compared to switch to a head unit with a small discharge amount. It is good also as a structure provided with the switching means.

  In this case, the cumulative discharge amount recorded for each head unit is an average value obtained by dividing the sum of the cumulative discharge amounts for each nozzle opening constituting the head unit by the number of nozzle openings of the head unit. It is good to use.

At the time of the printing process, as shown in steps S205 and S206 in FIG. 4, it is preferable to compare the accumulated discharge amounts of the head units and select (determine) a head unit with a small accumulated discharge amount for printing.
Note that the printing method shown in FIG. 4 employs a cumulative discharge amount instead of the cumulative number of times used in the printing method shown in FIG. Since this is the same as the printing method shown in FIG. 3, detailed description thereof is omitted.

  Since the life of the nozzle openings constituting each head unit 36 to 39 is affected not only by the number of ink droplet ejections but also the amount of ink droplets ejected, the usage degree of each nozzle opening is recorded as a cumulative ejection amount. It is also effective to manage the above-mentioned, and it is possible to grasp the variation in the degree of use among the head units by the accumulated discharge amount stored for each head unit 36, 37, 38, 39. As a result, by using head units with a small cumulative discharge amount preferentially, it is possible to eliminate the uneven use of each head unit.

  Even when the printing frequency of a part of the paper width (for example, A4 size printing paper S3) is high, only the head unit (for example, the head unit 38) corresponding to the paper width is continuously used than the other head units. In addition, it is possible to prevent the occurrence of a problem that the life is exhausted early.

  Furthermore, as the cumulative discharge amount recorded for each head unit as described above, an average value obtained by dividing the sum of the cumulative discharge amounts for the respective nozzle openings constituting the head unit by the number of nozzle openings of the head unit. With this configuration, even if there is a variation in the cumulative discharge amount of individual nozzle openings within each head unit, the degree of use of each head unit can be evaluated comprehensively for each head unit. It is possible to simplify the process of selecting a head unit with a small number of heads.

1 is a schematic side view of a first embodiment of a printing apparatus according to the present invention. FIG. 2 is an explanatory diagram showing a relationship between a configuration of a print head of the printing apparatus of FIG. 1 and a corresponding paper width. 3 is a flowchart illustrating a procedure of a printing method performed by the printing apparatus illustrated in FIG. 1. It is a flowchart of other embodiment of the printing method implemented with the printing apparatus which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Printing apparatus (liquid ejecting apparatus), 11 ... Print head, 12 ... Housing | casing, 13 ... Paper tray, 16 ... Image recording part, 17 ... Control unit, 33 ... Head unit control part, 36, 37, 38, 39 ... head unit, 36a, 36b, 36c, 36d ... nozzle row, 37a, 37b, 37c, 37d ... nozzle row, 38a, 38b, 38c, 38d ... nozzle row, 39a, 39b, 39c, 39d ... nozzle row, 41, 42, 43, 44 ... nozzle opening, 51 ... storage means, 53 ... switching means, S ... printing paper, S1 ... A3 size printing paper, S2 ... B4 size printing paper, S3 ... A4 size printing paper, S4 ... Postcard-sized printing paper.

Claims (8)

A liquid ejecting apparatus that ejects liquid onto a recording medium from a nozzle opening,
A liquid ejecting apparatus, wherein a plurality of head units corresponding to the width of the recording medium are arranged in parallel in the conveyance direction of the recording medium. The liquid ejecting apparatus according to claim 1,
Recording means for storing the cumulative number of times used for each head unit corresponding to the width of the recording medium;
A liquid ejecting apparatus comprising: a switching unit that compares the accumulated number of times of use for each head unit stored in the recording unit and switches to a head unit that has a smaller number of accumulated times of use. The liquid ejecting apparatus according to claim 1,
Recording means for storing a cumulative discharge amount for each head unit corresponding to the width of the recording medium;
A liquid ejecting apparatus comprising: a switching unit that compares the accumulated discharge amount for each head unit stored in the recording unit and switches to a head unit with a small discharge amount. A liquid ejecting method for ejecting liquid onto a recording medium from a nozzle opening,
The width of the recording medium is automatically recognized by the sensor or recognized by the guide position of the transport tray,
A liquid ejecting method, wherein a head unit capable of ejecting onto a recording medium is selected from a plurality of head units corresponding to the width of the recording medium. The liquid ejecting method according to claim 4,
For each head unit, the cumulative use count is stored in the recording means,
A liquid ejecting method comprising: comparing the accumulated number of times of use of each head unit at the time of the ejection process, and selecting and ejecting a head unit having a smaller cumulative number of times of use. The liquid ejecting method according to claim 5,
As the cumulative number of times used for recording for each head unit, an average value obtained by dividing the sum of the cumulative number of times used for each nozzle opening constituting the head unit by the number of nozzle openings of the head unit is used. Liquid jetting method. The liquid ejecting method according to claim 4,
The cumulative discharge amount is stored in the recording means for each head unit,
A liquid ejecting method comprising: comparing the accumulated discharge amount of each head unit and performing an ejection process by selecting a head unit having a small accumulated discharge amount during the ejection process. The liquid ejecting method according to claim 7,
As the cumulative discharge amount recorded for each head unit, an average value obtained by dividing the total of the cumulative discharge amounts for the respective nozzle openings constituting the head unit by the number of nozzle openings of the head unit is used. Liquid jetting method.

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