JP6526994B2 - Ink jet recording device - Google Patents

Description

  The present invention relates to an inkjet recording apparatus in which a plurality of print heads for ejecting ink droplets for performing recording on a recording medium are arranged in order of ejection at predetermined intervals in the conveyance direction of the recording medium.

  2. Description of the Related Art In recent years, an inkjet recording apparatus that realizes high-speed recording on a recording medium such as continuous paper or a sheet has been put to practical use. Such an inkjet recording apparatus includes a long print head in which a large number of nozzles for ejecting ink droplets onto the recording medium are arranged in a direction (width direction of the recording medium) orthogonal to the conveyance direction of the recording medium. Because the print head does not have to move in the width direction of the recording medium when discharging ink droplets in the width direction of the recording medium, the recording medium may be transported while the print head moves while discharging. Realizes faster recording than home-use inkjet printers.

  In order for the print head to provide good quality recording, it is necessary to prevent nozzle clogging. The clogging of the nozzle is often caused by the solidification of the ink surface filling the nozzle due to drying if the ink droplet is not ejected from the nozzle for a certain period of time. In order to prevent clogging of the nozzles, a home-use inkjet printer appropriately moves the print head to the standby position even during recording, and discharges ink droplets to an ink receiver provided at the standby position.

  On the other hand, in the above-described inkjet recording apparatus, the print head does not move to the standby position during recording, so in order to prevent clogging of the nozzles provided in a large number of rows, discharge is performed to perform recording on the recording medium Apart from that, it is necessary to carry out the discharge which does not contribute to the recording. Such discharge is called "flushing discharge".

  The flushing discharge includes continuous discharge (referred to as “line flushing”) in which discharge from all the nozzles is continuously performed on the recording medium at predetermined intervals (discrete discharge in which discharge from all the nozzles is performed discretely (referred to as “line flushing”). For example, Patent Document 1 discloses an ink jet recording apparatus which is called “star flushing” and appropriately selects and executes these two types of flushing discharge.

JP 2013-59875

  Since it is not necessary to consider the influence of the recording quality if it is a portion outside the recording area of the recording medium, for example, a portion to be finally cut, line flushing is selected as the flushing discharge. Line flushing prevents the clogging of nozzles by discharging ink droplets in relatively large amounts.

  On the other hand, if within the recording area of the recording medium, star flushing is selected as the flushing discharge. Since star flushing affects the recording quality because it discharges ink droplets that do not contribute to recording, it is not possible to discharge a large amount of ink droplets, but even if there are few cut portions in the recording medium, the nozzle Prevent clogging.

  Line flushing, star flushing, and any flushing discharge are discharges of ink droplets that do not contribute to recording, so there is nothing but economical or resource waste of ink. Therefore, it is desired to realize the flushing discharge which reduces the ink consumption while preventing the clogging of the nozzles.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide an ink jet printing apparatus capable of realizing the reduction of the flushing discharge amount.

  The present inventors earnestly studied in order to solve the above problems, and as a result, they obtained the following findings.

  The clogging of the nozzles in the print head of the ink jet printing apparatus is mainly caused by the solidification of the ink by drying, so if the appropriate humidity is supplied near the print head, the clogging of the nozzles due to the drying is Although this can be prevented, providing a mechanism for supplying moisture to the inside of the ink jet printing apparatus for that purpose has the problem of additional cost. In view of this, attention was focused on the fact that the flushing discharge itself for discharging ink droplets onto the recording medium is an operation of supplying moisture to the inside of the machine.

That is, in a plurality of print heads arranged in the discharge order with a predetermined interval along the conveyance direction of the recording medium, if the print head which discharges the recording medium first performs a relatively large amount of flushing discharge, the recording medium Since the moisture of the ink evaporated from the recording medium is supplied to the vicinity of the subsequent print head as it is transported to the vicinity of the subsequent print head, the nozzles are prevented from drying and clogging is suppressed. Can be reduced. The inventors have found that the total amount of ink discharge amount of flushing discharge by this method is smaller than the total amount of ink amount of flushing discharge of the conventional method, the present invention has the following embodiment or application example. Can be taken.
Application Example 1

An inkjet recording apparatus, comprising: a first droplet discharge unit and a second droplet discharge unit arranged in discharge order with a predetermined interval along the transfer direction of the recording medium, in the transfer direction The flushing discharge amount of the first droplet discharge unit is increased with respect to the recording medium to be conveyed, and the flushing discharge amount of the second droplet discharge unit is decreased according to the increase of the flushing discharge amount. And a flushing discharge control unit for performing a flushing discharge.
More specifically, conveying means for conveying a recording medium, which is continuous paper, along a predetermined conveyance direction, a first droplet discharge part and a first droplet discharge part arranged in the order of ejection with a predetermined interval in the conveyance direction An ink jet recording apparatus including the second droplet discharge unit, wherein the first droplet discharge unit performs a first flushing discharge for discharging a first droplet toward the recording medium; The transport means transports the recording medium on which the first droplet has landed toward the second droplet discharge unit along the transport direction, and the second droplet discharge unit is configured to A second flushing discharge for receiving a supply of moisture from the first droplet landed on the first droplet and discharging a second droplet toward the recording medium, and the inkjet recording apparatus transports in the transport direction The first droplet discharge onto the target recording medium It increases the flushing discharge amount, the flushing discharge amount of flushing ejection control means for causing the flushing discharge to reduce the flushing discharge amount of the second droplet ejecting section to correspond to the increase, further comprising a.
Application Example 2

In the ink jet recording apparatus, the first droplet discharge unit is a droplet discharge unit which is the first discharge sequence to the recording medium.
Application Example 3

In the inkjet recording apparatus, the flushing discharge control unit causes the first droplet discharge unit and the second droplet discharge unit to perform continuous droplet discharge as flushing discharge on the recording medium.
Application Example 4

In the inkjet recording apparatus, the flushing discharge control unit causes the first droplet discharge unit and the second droplet discharge unit to perform discrete droplet discharge as flushing discharge on the recording medium.
Application Example 5

An inkjet recording apparatus includes a recording medium water content detection hand stage, for detecting the water content of the recording medium, wherein the flushing discharge control means, content of the recording medium to the recording medium water content detection means detects The increase of the flushing discharge amount of the first droplet discharge part is changed according to the water content, and the decrease of the flushing discharge amount of the second droplet discharge part is changed.
More specifically, the inkjet recording apparatus is provided with a recording medium content water content detection means for detecting the water content content of the recording medium, and the flushing discharge control means is detected by the recording medium content water content detection means When the water content of the recording medium is small, the flushing discharge amount of the first droplet discharge portion is changed to be further increased, and when the water content of the recording medium is large, the first The flushing discharge amounts of the droplet discharge unit and the second droplet discharge unit are changed to be further reduced.
Application Example 6

An inkjet recording apparatus includes a recording medium surface temperature detecting hand stage, for detecting the surface temperature of the recording medium, wherein the flushing discharge control means, the surface temperature of the recording medium surface the recording medium temperature detecting means detects In accordance with this, the increase in the flushing discharge amount of the first droplet discharge part is changed, and the decrease in the flushing discharge amount of the second droplet discharge part is changed.
More specifically, the inkjet recording apparatus includes a recording medium surface temperature detecting unit that detects the surface temperature of the recording medium, and the flushing discharge control unit detects the recording detected by the recording medium surface temperature detecting unit. When the surface temperature of the medium is high, the flushing discharge amount of the first droplet discharge portion is changed to be further increased, and when the surface temperature of the recording medium is low, the first droplet discharge portion and the first droplet discharge portion The flushing discharge amount of the second droplet discharge unit is changed to be further reduced.
Application Example 7

In the ink jet recording apparatus, the first droplet discharge unit discharges black ink.
Application Example 8

In the inkjet recording apparatus, the first droplet discharge unit discharges an ink having a density lower than that of the ink discharged by the second droplet discharge unit.
Application Example 9

A flushing discharge method of an ink jet recording apparatus comprising a first droplet discharge part and a second droplet discharge part arranged in discharge order with a predetermined interval along a conveyance direction of a recording medium, comprising: And a step of increasing a flushing discharge amount of the first droplet discharge unit when the flushing discharge is performed on the recording medium transported in the transport direction, and a flushing discharge amount of the first droplet discharge unit. And D. reducing the flushing discharge amount of the second droplet discharge part in response to the increase.
More specifically, conveying means for conveying a recording medium, which is continuous paper, along a predetermined conveyance direction, a first droplet discharge part and a first droplet discharge part arranged in the order of ejection with a predetermined interval in the conveyance direction And a second droplet discharge unit, wherein the first droplet discharge unit is configured to perform the flushing discharge on the recording medium transported in the transport direction. And a step of performing a first flushing discharge for discharging a first droplet toward the recording medium, and the transport means moves the recording medium on which the first droplet has landed along the transport direction. The step of conveying toward the second droplet discharge unit, the second droplet discharge unit receives supply of moisture from the first droplet that has landed on the recording medium, and is directed to the recording medium A second flash for discharging a second droplet The second droplet discharge corresponding to the increase of the flushing discharge amount of the first droplet discharge part, and the step of increasing the flushing discharge amount of the first droplet discharge part. And D. reducing the flushing discharge amount of the part.

  In the application example 1, when the flushing discharge amount of the first droplet discharge unit which discharges the recording medium conveyed in the conveyance direction first is increased, the subsequent is performed correspondingly to the increase of the flushing discharge amount. Since the flushing discharge control means for reducing the flushing discharge amount of the second droplet discharge unit is provided, the moisture generated by the evaporation of the solvent of the ink droplet discharged onto the recording medium by the first droplet discharge unit is the first Since the nozzles of the second droplet discharge portion are prevented from being dried by being supplied near the second droplet discharge portion, the effect of reducing the amount of ink discharge used for the entire flushing discharge is obtained.

  In Application Example 2, since the first droplet discharge unit has the first discharge order with respect to the recording medium, moisture is supplied to all the subsequent second droplet discharge units to prevent the nozzle from being dried. It is possible to obtain the effect of reducing the amount of ink discharge used for the flushing discharge.

  In Application Example 3, even if the flushing discharge control unit causes the first droplet discharge unit and the second droplet discharge unit to perform continuous droplet discharge, the increase in the flushing discharge amount of the first droplet discharge unit Since the flushing discharge amount of the second droplet discharge unit is reduced correspondingly to the above, the effect of reducing the ink discharge amount used for the entire flushing discharge can be obtained.

  In Application Example 4, even if the flushing discharge control unit causes the first droplet discharge unit and the second droplet discharge unit to perform discrete droplet discharge, the increase in the flushing discharge amount of the first droplet discharge unit Since the flushing discharge amount of the second droplet discharge unit is reduced correspondingly to the above, the effect of reducing the ink discharge amount used for the entire flushing discharge can be obtained.

  In application example 5, the flushing discharge control means changes the increase in the flushing discharge amount of the first droplet discharge part according to the water content contained in the recording medium detected by the recording medium water content detecting means, and copes with the increase Since the reduction of the flushing discharge amount of the second flushing droplet discharge unit is changed, the effect of reducing the ink discharge amount used for the entire flushing discharge can be obtained.

  In Application Example 6, according to the surface temperature of the recording medium detected by the recording medium surface temperature detecting means, the flushing discharge control means changes the increase of the flushing discharge amount of the first droplet discharge portion, and the above corresponding to the increase Since the reduction of the flushing discharge amount of the second flushing droplet discharge unit is changed, an effect of reducing the ink discharge amount used for the entire flushing discharge can be obtained.

  In Application Example 7, since the first droplet discharge unit discharges the black ink whose cost is relatively low, the ink discharge amount used for the entire flushing discharge can be reduced, and the cost for the ink becomes unnecessary. The effect of not increasing it is obtained.

  In Application Example 8, since the first droplet discharge unit discharges ink having a lower concentration than the second droplet discharge unit, it is possible to reduce the amount of ink discharge used for the entire flushing discharge, and in particular, discretely An advantage is obtained that the recording quality is not unnecessarily reduced when the target droplet is discharged.

  In Application Example 9, when the flushing discharge amount of the first droplet discharge unit which discharges the recording medium transported in the transport direction first is increased, the subsequent is performed correspondingly to the increase of the flushing discharge amount. Since the flushing discharge amount of the second droplet discharge unit is decreased, the moisture generated by the evaporation of the solvent of the ink droplet discharged onto the recording medium by the first droplet discharge unit is in the vicinity of the second droplet discharge unit. By being supplied, in order to prevent the nozzle drying of the second droplet discharge unit, an operation and effect of reducing the ink discharge amount used for the entire flushing discharge can be obtained.

FIG. 1 is a schematic configuration diagram of an inkjet recording apparatus 100 according to an embodiment of the present invention. It is a figure for demonstrating the print head 13 in embodiment of this invention. It is a figure for demonstrating the line flushing in embodiment of this invention, and star flushing. It is a figure for demonstrating the principle of this invention. It is a figure for demonstrating the state which changed the flushing discharge amount in the line flushing in embodiment of this invention, and star flushing. It is a figure for demonstrating the state which changed the order of the discharge amount of the flushing discharge in embodiment of this invention. It is a figure for demonstrating the change of the arrangement | sequence of the print head in embodiment of this invention. It is a schematic block diagram of the inkjet recording device 200 in embodiment of this invention. It is a schematic block diagram of the inkjet recording device 300 in embodiment of this invention. FIG. 1 is a schematic diagram of an inkjet recording system 1000 according to an embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described using the drawings.

First Embodiment
FIG. 1 is a schematic configuration view for explaining an inkjet recording apparatus 100 according to the present invention.

  The inkjet recording apparatus 100 includes a paper feed unit 3, a recording unit 5, and a paper discharge unit 7.

  The sheet feeding unit 3 rotatably holds the roll-shaped continuous sheet WP around the horizontal axis, and unwinds and supplies the continuous sheet WP to the recording unit 5. The recording unit 5 performs printing on the continuous paper WP. The discharge unit 7 winds the web paper WP printed by the recording unit 5 around the horizontal axis. When the supply side of the continuous paper WP is upstream and the discharge side of the continuous paper WP is downstream, the paper feed unit 3 is disposed upstream of the recording unit 5, and the paper discharge unit 7 is downstream of the recording unit 5 It is arranged.

  The above-described continuous paper WP corresponds to the “recording medium” in the present invention.

  The recording unit 5 includes a plurality of drive rollers 11, a plurality of conveyance rollers 12, a plurality of print heads 13, a heat roller 14, and a control unit 15.

  The driving roller 11 is a roller for supplying a driving force for transporting the continuous paper WP taken in from the paper feeding unit 3 to the paper discharging unit 7. The conveyance roller 12 is a roller for smoothly conveying the continuous paper WP taken in by the drive roller 11. The driving roller 11 is provided immediately after the paper feed unit 3, immediately before the print head 13, immediately after the print head 13, immediately before the paper discharge unit 7, and is a tension for performing appropriate recording on the continuous paper WP. It also has the ability to The transport roller 12 is also provided with a function of supporting the tensioned continuous paper WP at the recording position, and a function of suppressing meandering and skewing of the continuous paper WP.

  The print head 13 forms an image by discharging ink supplied from an ink tank (not shown) to the continuous paper WP as ink droplets. Each print head 13 has a length equal to or greater than the paper width direction of the continuous paper WP in the paper width direction of the continuous paper WP being conveyed (direction orthogonal to the conveyance direction), and maintains a predetermined distance from the continuous paper WP It is constructed to do.

  In the recording unit 5, the print heads 13K, 13C, 13M, and so on have predetermined intervals so as to eject the black (K), cyan (C), magenta (M), and yellow (Y) inks from the upstream side. It is equipped with 13Y. Here, the width of the print head 13 in the transport direction is 15 cm, and the print heads 13 are arranged at an interval of 20 cm. The width of the print head 13 in the transport direction and the distance between the print heads 13 are not limited to this.

  The print head 13 records an image on the continuous paper WP supported by the conveyance roller 12 and also performs flushing discharge for preventing clogging of the nozzles.

  The print head 13 described above corresponds to the “droplet discharge portion” in the present invention.

  The heat roller 14 incorporates a heating unit such as a heater in order to dry the ink discharged onto the continuous paper WP by each print head 13 and transports the continuous paper WP while winding it at a large winding angle. The heat roller 14 winds the continuous paper WP around the outer peripheral surface, and dries the ink droplets discharged on the continuous paper WP.

  The above-described configurations are generally operated by the control unit 15 having a CPU and a memory. The control unit 15 conveys the web paper WP to the recording unit 5 by controlling the paper feeding unit 3, the driving roller 11, and the paper discharge unit 7. Further, the control unit 15 receives print data for printing from an image processing apparatus (not shown), converts it into ink droplet discharge data in the print head 13, and drives the print head 13 to print on the continuous paper WP .

  The control unit 15 also includes a flushing discharge control unit 151 that controls flushing discharge for preventing clogging of the plurality of nozzles arranged in the print head 13.

  The flushing discharge control unit 151 performs control to appropriately select line flushing or star flushing according to the recording state of the print head 13 on the continuous paper WP. Further, the flushing discharge control unit 151 changes the ink droplet discharge amount of the print head 13 that performs the flushing discharge on the continuous paper WP in advance, thereby the ink droplet discharge of the print head 13 that performs the flushing discharge. Control to reduce the amount.

  The above-described flushing discharge control unit 151 corresponds to the "flushing discharge control means" in the present invention.

  FIG. 2 is a diagram for explaining the configuration of the print head 13. The print head 13 realizes a length equal to or greater than the width direction of the continuous paper WP by arranging the plurality of inkjet heads 130 in the paper width direction (direction orthogonal to the transport direction) of the continuous paper WP.

  Each inkjet head 130 includes a plurality of nozzles 131 that eject ink under the control of the control unit 15. The print head 13 in which a plurality of inkjet heads 130 having a plurality of nozzles 131 are arranged in a row arranges the movement of the continuous paper WP in the width direction by discharging ink droplets to the continuous paper WP passing downward by conveyance. An image can be formed without performing. An ink jet recording apparatus having such a configuration is referred to as a "one-pass type ink jet recording apparatus".

  The number and the row position of the inkjet heads 130 in the print head 13 and the number and the row position of the nozzles 131 in the inkjet head 130 are not limited to those illustrated.

  FIG. 3 is a view for explaining the flushing discharge in the one-pass type ink jet recording apparatus.

  FIG. 3A is a diagram for explaining line flushing by the one-pass ink jet recording apparatus. Here, for the sake of explanation, it is assumed that the print head 13 includes one ink jet head 130, the number of nozzles 131 is five, and the web paper WP is transported in the transport direction H direction.

  When the control unit 15 determines that the flushing discharge for preventing clogging of the nozzles 131 is necessary, the flushing discharge control unit 151 selects the line flushing. The flushing discharge control unit 151 discharges ink to the print head 13 when the continuous print paper is transported in the transport direction H and the cut portion of the finished printed material reaches the lower side of the print head 13. To direct.

  The flushing discharge control unit 151 causes a large amount of ink discharge from the time of recording to be performed from all the nozzles 131 provided in the ink jet head 130 constituting the print head 13. As a result, as shown in the drawing, ink droplets are discharged from all the nozzles 131 provided in the ink jet head 130, whereby the line-shaped flushing discharge FL1 is performed in the direction orthogonal to the conveyance direction of the continuous paper WP.

  The flushing discharge control unit 151 may perform line flushing to prevent clogging of the nozzles each time a cut portion appears in the printed material completed by the conveyance of the continuous paper WP.

  The line flushing described above corresponds to "continuous droplet discharge" in the present invention.

  On the other hand, it is difficult to perform line flushing when there are few cut parts in the printed matter or when the area as the printed matter in the continuous paper WP is large. In such a case, if the control unit 15 determines that flushing discharge for preventing clogging of the nozzles 131 is necessary, the flushing discharge control unit 151 selects star flushing.

FIG. 3B is a view for explaining star flushing by the one-pass ink jet recording apparatus. As in FIG. 3A, for the sake of explanation here, it is assumed that the print head 13 includes one ink jet head 130, the number of nozzles 131 is five, and the web paper WP is transported in the transport direction H. .

  While the continuous paper WP is conveyed and image formation is performed, the flushing discharge control unit 151 which has selected the star flushing instructs the print head 13 to discharge the ink.

  The flushing discharge control unit 151 discretely discharges recording droplets or small droplets smaller than the recording droplets from all the nozzles 131 included in the inkjet head 130 constituting the print head 13. As a result, as shown in the drawing, the ink droplets are discharged from all the nozzles 131 provided in the ink jet head 130, thereby performing the flushing discharge FL2 in which the ink droplets are scattered in the direction orthogonal to the transport direction of the continuous paper WP.

  In star flushing, ink droplets by flushing are also present in the finished printed matter, but these ink droplets are not visually noticeable due to the scattering of droplets, and this is usually not a problem. .

  The above-described star flushing corresponds to “discrete droplet discharge” in the present invention.

  In the one-pass type inkjet recording apparatus, clogging of the nozzles is prevented without moving the print head 13 to the standby position by appropriately using line flushing and star flushing.

  FIG. 4 is a diagram for explaining the principle of the present invention. Here, for the sake of explanation, it is assumed that the print heads 13 K and 13 C of the recording unit 5 having a predetermined interval perform the flushing discharge on the continuous paper WP.

  FIG. 4A shows a state in which the print head 13K that discharges the continuous paper WP first performs flushing discharge. When the web paper WP is transported in the transport direction H, the print head 13 K performs flushing discharge on the web paper WP earlier than the print head 13 C in the order of arrangement. When the ink droplets FLD ejected by the print head 13K land on the continuous paper WP, the ink solvent penetrates into the continuous paper WP and a part thereof evaporates in the air.

  While the continuous paper WP is being conveyed to the separated print head 13C, the evaporation of the ink solvent inside the continuous paper WP by the ink droplets FLD continues. As a result of conveyance, the portion of the continuous paper WP on which the ink droplet FLD has landed reaches the lower portion of the print head 13C.

  FIG. 4B shows a state in which the portion on which the ink droplet FLD of the continuous paper WP lands reaches the lower part of the print head 13C by conveyance. When moisture S (indicated by a broken arrow) generated by evaporation of the ink solvent in the ink droplet FLD drifts near the print head 13C, the humidity around the print head 13C increases, and the nozzles arranged in the print head 13C are arrayed. Drying of 131 is prevented. Therefore, when the print head 13K and the print head 13C are compared, the print head 13C has less clogging of the nozzles.

  Based on this finding, the inventors etc. recover the nozzle clogging of the print head 13 by increasing the flushing discharge amount of the print head 13 which performs the flushing discharge first to the continuous paper WP, and the following print Since the humidity around the head 13 can be increased to prevent clogging of the nozzles, it is possible to reduce the flushing discharge amount of the print head 13 following, and the present invention can be conceived to reduce the overall flushing discharge amount. It came to

  FIG. 5 is a diagram for explaining a state in which the flushing discharge amount is changed in the print head 13 of the recording unit 5 and a decrease in the flushing discharge amount due to the change.

  FIGS. 5A and 5B show states in which the print head 13 has performed line flushing. In FIG. 5A, when the print heads 13K, 13C, 13M, and 13Y arranged so as to have predetermined intervals in the discharge order in the conveyance direction of the continuous paper WP perform line flushing, the flushing discharge amount of the print head 13K In the case shown in FIG. 5B, there is no change in the flushing discharge amount of each print head 13 as in the prior art. The case is shown.

  Specifically, in FIG. 5A, the flushing discharge amount of the print head 13K that discharges first on the continuous paper WP is set to four lines (the discharge for one line is repeated four times), and the print head 13C follows, While the flushing discharge amounts of 13M and 13Y are two lines each, in FIG. 5B, the flushing discharge amounts of the print heads 13 are three lines.

  In FIG. 5A, the flushing discharge amount of the print head 13K that performs the flushing discharge first is four lines, which is an increase of one line over the conventional three lines. When the print head 13K alone is seen, although the flushing discharge amount is increased, the moisture generated from the continuous paper WP is the subsequent print head 13C, because the print head 13K performs the flushing discharge by a relatively large amount. Increase the ambient humidity of 13M and 13Y. As a result, nozzle clogging due to drying of the print heads 13C, 13M, and 13Y is less likely to occur, and the flushing discharge amount of the print heads 13C, 13M, and 13Y can be two lines, respectively. The flushing discharge amount is 10 lines.

  On the other hand, in FIG. 5B, since the flushing discharge is performed by the conventional method, the flushing discharge amount of the print head 13K performing the discharge first is 3 lines, but the subsequent printing by the flushing discharge of the print head 13K is performed. Since the supply of humidity to the heads 13C, 13M and 13Y is not taken into consideration, the amount of flushing discharge of the print heads 13C, 13M and 13Y is three lines, which is the same as the three lines of flushing discharge amount of the print head 13K. The entire flushing discharge amount is 12 lines.

  That is, the flushing discharge amount in the line flushing of the print head 13K that discharges the continuous paper WP first is increased, and the flushing discharge amount of the following print heads 13C, 13M, and 13Y is decreased to perform line flushing. The ink droplet ejection amount is decreasing.

  FIGS. 5C and 5D show states in which the print head 13 has performed star flushing. In FIG. 5C, when the print heads 13K, 13C, 13M, and 13Y arranged in the order of discharge in the conveyance direction of the continuous paper WP perform star flushing, the flushing discharge amount of the print head 13K is the same as the print head 13C, FIG. 5D shows the case where the amount of flushing discharge of each print head 13 is not changed as in the conventional case.

  Specifically, in FIG. 5C, it is assumed that the flushing discharge amount of the print head 13K that discharges first on the continuous paper WP is discrete flushing discharge for 4 dots / A4, that is, 4 dots per A4 size. In FIG. 5D, while the subsequent flushing discharge amounts of the print heads 13C, 13M, and 13Y are 2 dots / A4, that is, discrete flushing discharges for 2 dots per A4 size are performed. The flushing discharge amount of each print head 13 is 3 dots / A4.

  Also in FIG. 5C, the flushing discharge amount of the print head 13K that performs the flushing discharge first is 4 dots / A4, which is larger than the conventional 3 dots / A4. When the print head 13K alone is seen, although the flushing discharge amount is increased, the moisture generated from the continuous paper WP is the subsequent print head 13C, because the print head 13K performs the flushing discharge by a relatively large amount. Increase the ambient humidity of 13M and 13Y. As a result, nozzle clogging due to drying of the print heads 13C, 13M, and 13Y is less likely to occur, and the flushing discharge amount of the print heads 13C, 13M, and 13Y can be 2 dots / A4, respectively. The typical flushing discharge amount is 10 dots / A4.

  On the other hand, in FIG. 5D, since the flushing discharge is performed by the conventional method, the flushing discharge amount of the print head 13K performing the discharge first is 3 dots / A4, but the subsequent discharge by the flushing discharge of the print head 13K is performed. Since the supply of humidity to the print heads 13C, 13M and 13Y is not taken into consideration, the flushing discharge amount of the print heads 13C, 13M and 13Y is the same as the flushing discharge amount 3dot / A4 of the print head 13K. The typical flushing discharge amount is 12 dots / A4.

  That is, by increasing the flushing discharge amount in star flushing of the print head 13K that discharges the continuous paper WP first, and decreasing the flushing discharge amount of the following print heads 13C, 13M, 13Y, star flushing is performed. The ink droplet ejection amount is decreasing.

  Here, the print head 13K corresponds to the "first droplet discharge unit" in the present invention, and the print heads 13C, 13M, and 13Y correspond to the "second droplet discharge unit".

  Also, the black (K) ink ejected by the print head 13K is relatively cheaper than the cyan (C) ink, the magenta (M) ink, and the yellow (Y) ink ejected by the print heads 13C, 13M, and 13Y. Even if the ink is discharged in relatively large quantities, the economic impact can also be suppressed.

  It is desirable that the setting of the flushing discharge amount of the print head 13 with respect to the continuous paper WP be set in consideration of the distance between the print heads 13. For example, if the distance between the print heads 13 is relatively long, the print head 13 corresponding to the “first droplet discharge unit” performs a relatively large amount of flushing, and the distances between the print heads 13 are compared. In the case where the print head 13 corresponding to the “first droplet discharge portion” performs a relatively small amount of flushing discharge, it is possible to achieve both the prevention of nozzle clogging and the reduction of the entire flushing discharge amount. it can.

  Further, the setting of the flushing discharge amount of each print head 13 with respect to the continuous paper WP is not limited to the above-mentioned value. For example, if the flushing discharge amount of the print head 13K is 4 lines or 4 dots / A4, the flushing discharge amount of the print head 13C following is 3 lines or 3 dots / A4, and the print head 13M of the print head 13M follows The flushing ejection amount may be two lines or 2 dots / A4, and the flushing ejection amount of the print head 13Y following the print head 13M may be one line or 1 dot / A4. Even in this case, the overall flushing discharge amount can be reduced as compared with the conventional method.

  Here, the print head 13 K corresponds to the “first droplet discharge portion” in the present invention, and the print head 13 C corresponds to the “second droplet discharge portion” in the present invention. However, the print head 13C corresponds to the "first droplet discharge portion" in the present invention with respect to the print head 13M, and the print head 13M corresponds to the "second droplet discharge portion" in the present invention. . Similarly, the print head 13M corresponds to the "first droplet discharge portion" in the present invention with respect to the print head 13Y, and the print head 13Y corresponds to the "second droplet discharge portion" in the present invention. Become.

  Further, the “first droplet discharge unit” in the present invention is not limited to the print head 13 that discharges the continuous paper WP first. FIG. 6 illustrates the case where the flushing discharge amount of the print head 13C is increased without changing the flushing discharge amount of 13K among the print heads 13K to 13Y arranged in the transport direction with a predetermined interval. It is a figure for.

  In FIG. 6A, the flushing discharge amount of the print head 13K is three lines as in the conventional case, the flushing discharge amount of the subsequent print head 13C is increased to four lines, and the print heads 13M and 13Y following the print head 13C. The flushing discharge amount of each is reduced to two lines.

  In FIG. 6B, the flushing discharge amount of the print head 13K is 3 dots / A4 as in the conventional case, and the flushing discharge amount of the subsequent print head 13C is increased from 3 dots / A4 to 4 dots / A4, and the printing head 13C follows the print head 13C. The flushing discharge amounts of the print heads 13M and 13Y are reduced to 2 dots / A4, respectively.

  Here, the K ink ejected from the print head 13 K that ejects the paper first on the continuous paper WP is relatively inexpensive but has a higher density than the other inks, and particularly increases the amount of flushing during star flushing. When this is done, the recording quality may be deteriorated, for example, the formed image may become dark, so the flushing ejection amount of C ink having a density lower than that of K ink is increased.

  As a result, since the flushing discharge amount of C ink having a density lower than that of K ink is increased, the recording quality does not decrease as in the case where the flushing discharge amount of K ink is increased, and the subsequent M ink By reducing the flushing discharge amount of Y ink, the overall flushing discharge amount also decreases compared to the conventional method.

  Here, the print head 13C corresponds to the “first droplet discharge portion” in the present invention, and the print heads 13M and 13Y correspond to the “second droplet discharge portion” in the present invention.

  In addition, the order of the ink in the print head 13 of the recording unit 5 may be changed to increase the flushing discharge amount of the ink having a relatively low density by the print head 13 which discharges first on the continuous paper WP. Alternatively, a low density ink used for gradation expression may be applied to the print head 13 that first ejects the continuous paper WP to increase the flushing ejection amount.

  FIG. 7 is a view for explaining the case where the order of ink in the print head 13 is changed, and the case where the print head 13 for ejecting low density ink is added for gradation expression.

  FIG. 7A is a view for explaining the print heads 13Y, 13K, 13C, and 13M of the recording unit 5 in which the ink order is Y, K, C, and M, respectively. Such an arrangement of the print head 13 is made because the ink order changes depending on the type of ink and the recording content. In this case, since the print head 13 Y that discharges the continuous paper WP first discharges the Y ink with a relatively low density, even if the flushing discharge amount is increased, the K ink flushing discharge amount is increased. As compared with the above, the recording quality does not deteriorate, and by reducing the flushing discharge amount of the subsequent print head 13, the overall flushing discharge amount of the print head 13 is reduced.

  FIG. 7B shows light magenta (LC) having a density lower than that of C ink and light magenta having a density lower than that of M ink in addition to K, C, M, and Y inks that are normally used for gradation expression. It is a figure for demonstrating the recording part 5 which added print head 13LC, 13LM which discharges LM. In the ink jet recording apparatus, LC ink and LM ink may be used to realize high gradation expression. In that case, the number of the print heads 13 of the recording unit 5 is 4 to 6, and the print head 13 LC which discharges LC ink also in the arrangement of the print heads 13, the print head 13 C which discharges C ink, the print heads 13 K, 13 Y, LM A print head 13LM that discharges ink and a print head 13M that discharges M ink are used.

  When such an arrangement of the print heads 13 is formed, even if the flushing discharge amount of the print head 13LC to be discharged first on the continuous paper WP, in particular, the flushing discharge amount of the star flushing is increased, LC having a relatively low density Since the ink does not greatly affect the recording quality, reducing the subsequent flushing discharge amount of the print head 13 also reduces the overall flushing discharge amount of the print head 13.

  As described above, in the inkjet recording apparatus of FIG. 1, the flushing discharge control unit 151 increases the flushing discharge amount of the print head 13 that discharges first on the continuous paper WP and decreases the flushing discharge amount of the subsequent print head 13. As a result, the overall flushing discharge amount can be reduced.

Second Embodiment
FIG. 8 is a schematic configuration view for explaining an inkjet recording apparatus 200 according to the present invention. With regard to the paper feed unit 32, the paper discharge unit 72, the drive roller 21 of the recording unit 52, the conveyance roller 22, the print head 23, and the heat roller 24, which are components of the ink jet recording apparatus 200, the ink jet recording apparatus 100 shown in FIG. Since it is the same as, the explanation is omitted.

  The inkjet recording apparatus 200 includes a sheet moisture measuring unit 26 that measures the moisture content of the continuous paper WP fed from the paper feeding unit 32. The paper moisture measurement unit 26 measures the moisture contained in the continuous paper WP and notifies the control unit 25 of the moisture. The sheet moisture measurement unit 26 may adopt any of a structure in which contact measurement is performed and a structure in which non-contact measurement is performed.

  Here, the paper moisture measurement unit 26 corresponds to the “recording medium contained moisture content detection means” in the present invention.

  The control unit 25 has the same function as the control unit 15 shown in FIG. 1, but additionally has a flushing discharge control unit 251. The flushing discharge control unit 251 has the same function as the flushing discharge control unit 151 shown in FIG. 1 and, based on the moisture content of the continuous paper WP notified from the paper moisture measuring unit 26, each print head 23 Control the flushing discharge amount of

  Here, the flushing discharge control unit 251 corresponds to the “flushing discharge control means” in the present invention.

  When the water content of the continuous paper WP is relatively small, the amount of permeation of the ink droplets discharged onto the continuous paper WP into the continuous paper WP is higher than the amount of evaporation of the continuous ink WP. By further increasing the flushing discharge amount of the print head 23 which performs the discharge first, the humidity supply to the subsequent print head 23 is achieved.

  On the other hand, when the water content of the continuous paper WP is relatively large, if a large amount of flushing discharge is performed on the continuous paper WP, the water content of the continuous paper WP may be excessive, which may cause problems such as cockling. In addition, since the humidity is supplied to each print head 13 from the continuous paper WP itself, clogging of the nozzles tends to be suppressed.

  Therefore, when the water content of the continuous paper WP is relatively large, the flushing discharge control unit 251 decreases the flushing discharge amount of the print head 23 that discharges the continuous paper WP first, and the subsequent print head 23 Similarly, the flushing discharge amount is decreased.

  In the inkjet recording apparatus 200 shown in FIG. 8, based on the moisture content of the continuous paper WP, the flushing discharge control unit 251 increases the flushing discharge amount of the print head 23 that discharges the continuous paper WP first. By reducing the flushing discharge amount of the print head 23, the overall flushing discharge amount is reduced.

Third Embodiment
FIG. 9 is a schematic configuration view for explaining an ink jet recording apparatus 300 according to the present invention. The ink jet recording apparatus 100 shown in FIG. 1 is a constituent element of the ink jet recording apparatus 300, and the paper feed unit 30, the paper discharge unit 70, the drive roller 31 of the recording unit 53, the conveyance roller 32, the print head 33 and the heat roller 34. Since it is the same as, the explanation is omitted.

  The inkjet recording apparatus 300 includes a surface temperature measurement unit 36 that measures the surface temperature of the continuous paper WP fed from the paper feed unit 30. The surface temperature measurement unit 36 measures the surface temperature of the continuous paper WP and notifies the control unit 35 of the measurement. The surface temperature measurement unit 36 may adopt any of a structure that performs contact measurement and a structure that performs noncontact measurement.

  Here, the surface temperature measurement unit 36 corresponds to the “recording medium surface temperature detection means” in the present invention.

  The control unit 35 has a function similar to that of the control unit 15 shown in FIG. 1, but additionally has a flushing discharge control unit 351. The flushing discharge control unit 351 has the same function as the flushing discharge control unit 351 shown in FIG. 1 and, based on the surface temperature of the continuous paper WP notified from the surface temperature measuring unit 36, each print head 33. Control the flushing discharge amount of

  Here, the flushing discharge control unit 351 corresponds to the "flushing discharge control means" in the present invention.

  When the surface temperature of the continuous paper WP is relatively high, the evaporation amount of the ink solvent of the ink droplets discharged onto the continuous paper WP increases, so the ink solvent attached to the continuous paper WP by the print head 13 that performs flushing discharge first. Evaporation may end before reaching the subsequent print head 33. In such a case, the flushing discharge control unit 351 further supplies the humidity to the subsequent print head 33 by further increasing the flushing discharge amount of the print head 33 that discharges the continuous paper WP first. Plan.

  On the other hand, when the surface temperature of the continuous paper WP is relatively low, if a large amount of flushing is performed on the continuous paper WP, the moisture content of the continuous paper WP may be excessive, which may cause problems such as cockling.

  Therefore, when the surface temperature of the continuous paper WP is relatively low, the flushing discharge control unit 351 decreases the flushing discharge amount of the print head 33 that discharges the continuous paper WP first, and the following print head 33 Similarly, the flushing discharge amount is reduced.

  In the inkjet recording apparatus 300 shown in FIG. 9, based on the surface temperature of the continuous paper WP, the flushing discharge control unit 351 increases the flushing discharge amount of the print head 33 that discharges first on the continuous paper WP, and subsequent printing. By reducing the flushing discharge amount of the head 33, the overall flushing discharge amount is reduced.

Fourth Embodiment
FIG. 10 is a schematic configuration view for explaining an inkjet recording system 1000 according to the present invention.

  The inkjet recording system 1000 shown in FIG. 10 is shown in FIG. 1 as the recording section 5 shown in FIG. 1 as an inkjet recording apparatus for performing surface recording, and in FIG. The recording unit 5 is provided. Here, for the purpose of identification, the recording unit 5 which performs front side recording is referred to as a recording unit 5a, and the recording unit 5 which performs back side recording is referred to as a recording unit 5b.

  The inkjet recording system 1000 also includes a control unit 510 for controlling the paper feed unit 3, the recording units 5 a and 5 b, and the paper discharge unit 7 to perform printing.

  The control unit 510 is a computer provided with a CPU, a memory, and the like, and realizes image formation in the inkjet recording system 1000 by transmitting data for forming an image to the recording units 5a and 5b. In addition, a flushing discharge control unit 511 that controls the flushing discharge of the recording units 5a and 5b is provided. Here, the flushing discharge control unit 511 particularly controls the discharge amount of the flushing discharge in the recording unit 5 b.

  In the inkjet recording system 1000, the continuous sheet WP conveyed from the sheet feeding unit 3 is subjected to surface recording by the recording unit 5a, and then is reversed by the turn bar 6, and is subjected to back surface recording by the recording unit 5b. , And is taken up by the paper discharge unit 7.

  In the inkjet recording system 1000, since the web paper WP is heated by the heat drum 14 provided in the recording unit 5a, the nozzles of the print head 13 provided in the recording unit 5b through which the heated web paper WP passes are dried. Clogging tends to occur.

Therefore, the flushing discharge control unit 511 included in the control unit 510 of the inkjet recording system 1000 performs the flushing discharge amount of the print head 13K that discharges onto the continuous paper WP first in the recording unit 5b. By increasing the flushing discharge amount of the print head 13 K that discharges the paper WP, the flushing discharge amount of the subsequent print heads 13 C, 13 M, and 13 Y can be reduced in the recording unit 5 b. The flushing discharge amount can be reduced.
<Modification example>

  In the above description, K, C, M, Y, LC, and LM have been described for the ink ejected by the print head 13, but a configuration for ejecting special color inks such as R, G, B, etc. as the other inks is used. You may add it.

  In the above description, the control of the flushing discharge amount has been performed based on the moisture content of the continuous paper WP or the surface temperature of the continuous paper WP, but based on the ambient humidity of the recording unit 5, 52, 53. Control of flushing discharge may be performed. The humidity around the recording unit 5, 52, 53 may be detected by attaching a hygrometer to the airframe. Alternatively, the detection may be performed by the operator of the ink jet recording apparatus inputting ambient humidity to the control units 15, 25, 35.

  The configuration of the inkjet recording system 1000 has been described as the recording unit 5a performing surface recording, but surface recording may be performed by the recording unit 52 or the recording unit 53. Alternatively, the back side recording may be performed by the recording unit 52 or the recording unit 53.

  Further, in the inkjet recording system 1000, the flushing discharge amount of the print head 13K that discharges the recording section 5a first is increased, and the flushing discharge amount of the subsequent print heads 13C, 13M, and 13Y is decreased. It is also good.

  In the above description, the recording medium has been described as the continuous paper WP, but the present invention can be realized even if the recording medium is a sheet.

  In the above description, the recording medium has been described as the continuous paper WP, but the present invention can be realized even if the recording medium is a synthetic resin film or a metal film.

3, 30, 32 paper feed section
5, 5a, 5b, 52, 53 Recording unit
6 turn bar
7, 70, 72 Paper output unit
11, 21 and 31 Drive rollers
12, 22, 32 Transport roller
13, 23, 33 Printheads
14, 24, 34 Heat roller
15, 25, 35 510 Control unit
26 Paper Moisture Measurement Unit
36 Surface temperature measurement unit
100, 200, 300 inkjet recording device
130 Inkjet head
131 nozzles
151, 251, 351 511 Flushing discharge control unit
1000 inkjet recording system
FL1 Line flushing discharge
FL2 star flushing discharge
FLD flushing discharge ink drop
S moisture
WP continuous paper

Claims (9)

Conveying means for conveying a recording medium , which is continuous paper, along a predetermined conveyance direction, and a first droplet discharge portion and a second droplet discharge portion arranged in discharge order with a predetermined interval in the conveyance direction An inkjet recording apparatus comprising
The first droplet discharge unit performs a first flushing discharge for discharging a first droplet toward the recording medium.
The transport means transports the recording medium on which the first droplet has landed toward the second droplet discharge unit along the transport direction.
The second droplet discharge unit receives a supply of moisture from the first droplet landed on the recording medium, and discharges a second flushing discharge for discharging the second droplet toward the recording medium. Do,
The inkjet recording apparatus increases the flushing discharge amount of the first droplet discharge unit with respect to the recording medium conveyed in the conveyance direction, and the second recording medium corresponds to the increase of the flushing discharge amount. An inkjet recording apparatus, further comprising: a flushing discharge control unit for performing flushing discharge for reducing the flushing discharge amount of the droplet discharge unit. The inkjet recording apparatus according to claim 1, wherein
The first droplet discharge unit is the first droplet discharge unit in the order of discharge to the recording medium;
An inkjet recording apparatus characterized by The inkjet recording apparatus according to claim 1 or 2, wherein
The flushing discharge control unit causes the first droplet discharge unit and the second droplet discharge unit to perform continuous droplet discharge as flushing discharge on the recording medium;
An inkjet recording apparatus characterized by The inkjet recording apparatus according to claim 1 or 2, wherein
The flushing discharge control unit causes the first droplet discharge unit and the second droplet discharge unit to perform discrete droplet discharge as flushing discharge on the recording medium;
An inkjet recording apparatus characterized by The inkjet recording apparatus according to any one of claims 1 to 4, wherein
Recording medium moisture content detecting means to detect the moisture content of the recording medium,
Equipped with
The flushing discharge control means, wherein when the water content of the recording medium moisture content detecting means detects the recording medium is small, modified to further increase the flushing discharge amount of the first droplet ejecting section , when said water content of the recording medium is large, it is modified to further reduce the flushing discharge amount of the first droplet ejecting section and the second droplet ejecting section,
An inkjet recording apparatus characterized by The inkjet recording apparatus according to any one of claims 1 to 4, wherein
Recording medium surface temperature detecting means to detect the surface temperature of the recording medium,
Equipped with
The flushing discharge control means, wherein when the surface temperature of the recording medium said recording medium surface temperature detecting unit detects is high, modified to further increase the flushing discharge amount of the first droplet ejecting section, the When the surface temperature of the recording medium is low, the amount of flushing discharge of the first droplet discharge portion and the second droplet discharge portion may be further reduced.
An inkjet recording apparatus characterized by An ink jet recording apparatus according to any one of claims 1 to 6, wherein
The first droplet discharge unit discharges black ink;
An inkjet recording apparatus characterized by An ink jet recording apparatus according to any one of claims 1 to 6, wherein
The first droplet discharge unit discharges ink having a lower density than the ink discharged by the second droplet discharge unit.
An inkjet recording apparatus characterized by Conveying means for conveying a recording medium , which is continuous paper, along a predetermined conveyance direction, and a first droplet discharge portion and a second droplet discharge portion arranged in discharge order with a predetermined interval in the conveyance direction And a flushing discharge method of an ink jet recording apparatus comprising:
When performing flushing discharge on the recording medium conveyed in the conveyance direction,
Performing the first flushing discharge in which the first droplet discharge unit discharges the first droplet toward the recording medium;
The transport means transports the recording medium on which the first droplet has landed toward the second droplet discharge unit along the transport direction;
The second droplet discharge unit receives a supply of moisture from the first droplet that has landed on the recording medium, and discharges a second flushing discharge that discharges the second droplet toward the recording medium. The process to be performed,
Increasing the flushing discharge amount of the first droplet discharge unit;
Reducing the flushing discharge amount of the second droplet discharge part in response to the increase of the flushing discharge amount of the first droplet discharge part;
A flushing discharge method of an ink jet recording apparatus, comprising:

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