JP2020151987A - Liquid jet device and control method thereof - Google Patents

Abstract

To effectively reduce errors of an impact position caused by deformation of a medium.SOLUTION: A liquid jet device includes: a conveyance mechanism which conveys a medium along a first shaft; a medium support section which sucks the medium conveyed by the conveyance mechanism; a liquid jet head in which a plurality of nozzles for jetting liquid are arrayed along the first shaft; an acquisition section which acquires shape data of the shape of a first region including an end in the direction of the first shaft of the medium; and a control section which controls jetting of liquid by the liquid jet head. The conveyance mechanism conveys the medium by constant conveyance amount over the whole region of the medium in the direction of the first shaft. The control section makes timing when a first nozzle of the plurality of nozzles jets liquid to the first region different from timing when a second nozzle different from the first nozzle of the plurality of nozzles jets liquid to the first region according to the shape data.SELECTED DRAWING: Figure 2

Description

The present invention relates to a liquid injection device and a control method thereof.

Conventionally, a technique of injecting a liquid from a plurality of nozzles onto a medium such as printing paper has been proposed. When the medium is deformed such as curled, the distance between the surface of the medium and each nozzle is different for each nozzle, so that an error occurs at the position where the liquid lands on the surface of the medium. For example, Patent Document 1 discloses a configuration in which a medium is sucked by a plurality of suction holes formed on a transport surface facing the medium being transported in order to eliminate deformation of the medium.

Japanese Unexamined Patent Publication No. 2004-268417

When a part of the medium is placed on the transport surface, only a part of the plurality of suction holes sucks the medium. Therefore, the attractive force acting on the medium may be insufficient, and a state may occur in which the vicinity of the end portion of the medium in the transport direction is separated from the transport surface. That is, it is difficult to completely eliminate the deformation of the medium with the configuration of Patent Document 1 that sucks from the transport surface. Therefore, there is room for improving the error in the position where the liquid lands.

In order to solve the above problems, the liquid injection device according to the preferred embodiment of the present invention includes a transport mechanism for transporting the medium along the first axis and a medium support for sucking the medium transported by the transport mechanism. Shape data relating to the shape of the unit, the liquid injection head in which a plurality of nozzles for ejecting liquid are arranged along the first axis, and the shape of the first region of the medium including the end portion in the direction of the first axis. The acquisition unit includes an acquisition unit for acquisition and a control unit for controlling the injection of liquid by the liquid injection head, and the transfer mechanism transfers the medium with a constant transfer amount over the entire area of the medium in the direction of the first axis. The control unit conveys the timing of the first nozzle of the plurality of nozzles injecting liquid into the first region, and the first of the plurality of nozzles, which is different from the first nozzle. The timing of injecting the liquid into the region is made different according to the shape data.

A control method for a liquid injection device according to a preferred embodiment of the present invention includes a transfer mechanism that conveys a medium along a first axis, a medium support portion that sucks the medium conveyed by the transfer mechanism, and a liquid injection device. A plurality of nozzles are provided with a liquid injection head in which the nozzles are arranged along the first axis, and the transport mechanism transports the medium in a constant transport amount over the entire area of the medium in the direction of the first axis. This is a control method for a liquid injection device, in which shape data regarding the shape of a first region of the medium including an end in the direction of the first axis is acquired, and the first nozzle among the plurality of nozzles is the said. The timing of injecting the liquid into the first region and the timing of injecting the liquid into the first region by a second nozzle different from the first nozzle among the plurality of nozzles are made different according to the shape data.

It is a block diagram of the liquid injection apparatus which concerns on 1st Embodiment. It is explanatory drawing of the structure which carries a medium. It is a block diagram which illustrates the functional structure of the liquid injection device. It is a waveform diagram of various signals which define the operation of a liquid injection device. It is explanatory drawing of the error of the landing position. It is explanatory drawing of the error of the landing position. It is explanatory drawing of the 1st region and 2nd region in a medium. It is explanatory drawing of the operation of a liquid injection device. It is a graph which shows the landing surface, the interval of a nozzle, and the error of a landing position. It is explanatory drawing of the operation of the liquid injection apparatus in 2nd Embodiment. It is explanatory drawing of the operation of the liquid injection apparatus in the modification of 2nd Embodiment. It is explanatory drawing of acquisition of shape data in a modification. It is explanatory drawing of the modification.

A. 1st Embodiment FIG. 1 is a block diagram which illustrates the liquid injection apparatus 100 which concerns on 1st Embodiment. The liquid injection device 100 is an inkjet printing device that injects droplets of ink, which is an example of a liquid, onto the medium 11. The liquid injection device 100 of the first embodiment is a large format printer (LFP) capable of printing on a medium 11 having a paper width of, for example, about 64 inches. The medium 11 is typically printing paper, but a printing target of any material such as a resin film or a cloth is used as the medium 11. In the first embodiment, the roll paper 12 around which the medium 11 is wound around the core is installed in the liquid injection device 100.

As illustrated in FIG. 1, a liquid container 13 for storing ink is installed in the liquid injection device 100. For example, a cartridge that can be attached to and detached from the liquid injection device 100, a bag-shaped ink pack made of a flexible film, or an ink tank that can be refilled with ink is used as the liquid container 13.

As illustrated in FIG. 1, the liquid injection device 100 includes a control unit 21, a transfer mechanism 22, a moving mechanism 23, a liquid injection head 24, and a medium support portion 25. The control unit 21 controls each element of the liquid injection device 100. The control unit 21 includes, for example, a control device 211 and a storage device 212. The control device 211 is a single or plurality of processors that perform various operations and controls. Specifically, the control device 211 is configured by one or more types of processors such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a DSP (Digital Signal Processor), or an FPGA (Field Programmable Gate Array). To. The storage device 212 is a single or a plurality of memories for storing a program executed by the control device 211 and various data used by the control device 211. For example, a known recording medium such as a semiconductor recording medium and a magnetic recording medium, or a combination of a plurality of types of recording media is arbitrarily adopted as the storage device 212.

FIG. 2 is an explanatory diagram of a mechanism for transporting the medium 11. As illustrated in FIGS. 1 and 2, the transport mechanism 22 transports the medium 11 supplied from the roll paper 12 along the Y axis under the control of the control unit 21. Specifically, the transport mechanism 22 includes a supply mechanism 221 and a discharge mechanism 222. As illustrated in FIG. 2, the supply mechanism 221 includes a first supply roller 221a and a second supply roller 221b that are in contact with each other. The rotation axes of the first supply roller 221a and the second supply roller 221b are parallel to the X axis. The X-axis and the Y-axis are orthogonal to each other. Due to the rotation of one or both of the first supply roller 221a and the second supply roller 221b, the medium 11 passes between the two and is conveyed to the downstream side.

The discharge mechanism 222 includes a first discharge roller 222a and a second discharge roller 222b that are in contact with each other. The rotation axes of the first discharge roller 222a and the second discharge roller 222b are parallel to the X axis. By rotating one or both of the first discharge roller 222a and the second discharge roller 222b, the medium 11 supplied from the supply mechanism 221 passes between the two and is conveyed to the downstream side.

The transport mechanism 22 of the first embodiment transports the medium 11 in a constant transport amount over the entire area of the medium 11 in the Y-axis direction. Specifically, the transport mechanism 22 transports the medium 11 in a constant transport amount from the time when the front end of the medium 11 reaches the supply mechanism 221 until the rear end of the medium 11 is separated from the discharge mechanism 222 on the downstream side. To do. The “transportation amount” is the amount of movement of the medium 11 for one time in a configuration in which the medium 11 is intermittently conveyed over a plurality of times. In the configuration in which the medium 11 is continuously conveyed, the amount of movement of the medium 11 within a unit time corresponds to the “transportation amount”.

As understood from the above description, in the first embodiment, the upper end treatment or the lower end treatment for reducing the amount of ink conveyed to the medium 11 within the period of injecting ink into the region of the end portion of the medium 11 in the Y-axis direction is performed. Omitted. In the configuration in which the upper end processing or the lower end processing is executed, there is a problem that the control required for transporting the medium 11 is complicated and printing unevenness occurs inside and outside the area to be processed. In the first embodiment, since the upper end processing or the lower end processing is omitted, there is an advantage that the control processing is complicated and printing unevenness can be reduced.

The moving mechanism 23 of FIG. 1 repetitively reciprocates the liquid injection head 24 along the X axis under the control of the control unit 21. The moving mechanism 23 of the first embodiment includes a box-shaped transport body 231 for accommodating the liquid injection head 24 and an endless belt 232 to which the transport body 231 is fixed. It should be noted that a configuration in which a plurality of liquid injection heads 24 are mounted on the transport body 231 or a configuration in which the liquid container 13 is mounted on the transport body 231 together with the liquid injection head 24 can be adopted. The Y-axis parallel to the transport direction of the medium 11 is an example of the "first axis", and the X-axis parallel to the reciprocating direction of the liquid injection head 24 is an example of the "second axis".

The liquid injection head 24 ejects the ink supplied from the liquid container 13 from the plurality of nozzles N to the medium 11 under the control of the control unit 21. An image is formed on the surface of the medium 11 by the liquid injection head 24 ejecting ink onto the medium 11 in parallel with the transfer of the medium 11 by the transfer mechanism 22 and the repetitive reciprocation of the transfer body 231.

As illustrated in FIG. 2, the liquid injection head 24 includes a plurality of nozzles N, a plurality of pressure chambers C, and a plurality of drive elements E. The plurality of nozzles N are installed on the surface (hereinafter referred to as “injection surface”) F1 facing the medium 11 in the liquid injection head 24. The injection surface F1 is, for example, a flat surface parallel to the XY plane. The plurality of nozzles N are arranged along the Y axis on the injection surface F1. That is, a plurality of nozzles N are arranged along the transport direction of the medium 11. A plurality of rows of nozzles N arranged side by side along the X axis may be formed on the injection surface F1.

The pressure chamber C and the drive element E are formed for each nozzle N. The pressure chamber C is a space communicating with the nozzle N. The ink supplied from the liquid container 13 is filled in the plurality of pressure chambers C of the liquid injection head 24. The drive element E fluctuates the pressure of the ink in the pressure chamber C. For example, a piezoelectric element that changes the volume of the pressure chamber C by deforming the wall surface of the pressure chamber C, or a heat generating element that generates air bubbles in the pressure chamber C by heating ink in the pressure chamber C is a driving element E. It is preferably used as. The drive element E fluctuates the pressure of the ink in the pressure chamber C, so that the ink in the pressure chamber C is ejected from the nozzle N.

The medium support portion 25 is a structure including a surface (hereinafter referred to as “transport surface”) F2 facing the medium 11 conveyed by the transfer mechanism 22. The transport surface F2 is, for example, a flat surface parallel to the XY plane. In a plan view from the direction of the Z axis perpendicular to the XY plane, the medium support portion 25 is located between the supply mechanism 221 and the discharge mechanism 222. The injection surface F1 of the liquid injection head 24 faces the transport surface F2 at a predetermined interval. The medium 11 conveyed by the transfer mechanism 22 passes through the space between the injection surface F1 and the transfer surface F2.

The medium support portion 25 of the first embodiment sucks the medium 11 conveyed by the transfer mechanism 22. Specifically, a plurality of suction holes 251 are formed on the transport surface F2 of the medium support portion 25. The plurality of suction holes 251 are openings for sucking the medium 11 transported on the transport surface F2 by the transport mechanism 22. By suction using the plurality of suction holes 251 the medium 11 is conveyed along the transfer surface F2 in contact with the transfer surface F2. According to the above configuration, it is possible to reduce the error of the distance between each nozzle N of the liquid injection head 24 and the surface of the medium 11.

FIG. 3 is a block diagram illustrating a functional configuration of the liquid injection device 100. The transport mechanism 22 and the moving mechanism 23 are not shown in FIG. 3 for convenience. Further, FIG. 4 is a waveform diagram of various signals that define the operation of the liquid injection device 100.

As illustrated in FIG. 3, the control unit 21 supplies a plurality of signals including the control signal L and the instruction signal S to the liquid injection head 24. As illustrated in FIG. 4, the control signal L is a periodic signal that defines a period (hereinafter, referred to as “unit period”) U that is a unit of operation of the liquid injection head 24. Specifically, the control signal L includes a pulse arranged at the start point of each unit period U. The instruction signal S is a signal for instructing the presence or absence of ink injection for each of the plurality of nozzles N for each unit period U. The instruction signal S may indicate the amount of ink ejected by each nozzle N.

As illustrated in FIG. 3, the liquid injection head 24 includes a drive circuit 40. The drive circuit 40 drives each of the plurality of drive elements E under the control of the control unit 21. The drive circuit 40 of the first embodiment includes a signal generation unit 41, a signal processing unit 42, and a supply switching unit 43.

The signal generation unit 41 is a circuit that generates a drive signal D. As illustrated in FIG. 4, the drive signal D is a voltage signal that fluctuates with a unit period U as a cycle. The drive signal D is commonly used to drive the plurality of drive elements E. As illustrated in FIG. 4, the drive signal D includes one or more drive pulses Q for each unit period U. The drive pulse Q is a pulse for driving the drive element E. That is, when the drive element E operates by supplying the drive pulse Q, ink is ejected from the nozzle N corresponding to the drive element E.

The supply switching unit 43 of FIG. 3 is a circuit that individually switches the supply and stop of the drive signal D to the drive element E for each drive element E. Specifically, the supply switching unit 43 includes a plurality of switches 44 corresponding to different drive elements E. The switch 44 corresponding to each drive element E switches whether or not to supply the drive pulse Q of the drive signal D to the drive element E. When the switch 44 is in the on state, the drive pulse Q is supplied to the drive element E, and when the switch 44 is in the off state, the supply of the drive pulse Q to the drive element E is stopped.

The signal processing unit 42 controls the supply switching unit 43 according to the control signal L and the instruction signal S supplied from the control unit 21. Specifically, the signal processing unit 42 controls each switch 44 of the supply switching unit 43 according to the instruction signal S for each unit period U defined by the control signal L. The signal processing unit 42 responds to, for example, a multi-stage shift register that sequentially transfers the instruction signal S, a latch circuit that takes in the output signal from each shift register for each unit period U, and an output signal from the latch circuit. A decoding circuit that controls the opening and closing of each of the plurality of switches 44 is provided.

As described above, the medium 11 conveyed by the transfer mechanism 22 is sucked by the medium support portion 25. Therefore, ideally, the medium 11 is conveyed in the direction of the Y axis in a state parallel to the XY plane by coming into contact with the conveying surface F2. However, in reality, as shown by the broken line in FIG. 2, the medium 11 may be transported in a state of being separated from the transport surface F2. For example, curl caused by winding the medium 11 around the winding core may occur on the medium 11 on the transport surface F2. When the medium 11 is deformed on the transport surface F2 as described above, an error may occur at the position where the ink ejected from the liquid injection head 24 lands on the surface (hereinafter referred to as “landing surface”) F3 of the medium 11. There is sex. In the following description, the position on the X-axis where the ink lands on the landing surface F3 is referred to as the “landing position”.

5 and 6 are explanatory views of the error of the landing position x. The distance G between the landing surface F3 and the nozzle N is shown in FIGS. 5 and 6. The distance G between the landing surface F3 and the nozzle N is the distance between the region where the nozzle N is formed on the injection surface F1 and the region of the landing surface F3 of the medium 11 facing the nozzle. As illustrated in FIGS. 5 and 6, the position of the landing surface F3 of the medium 11 in the Z-axis direction changes according to the deformation of the medium 11. Therefore, the distance G between the landing surface F3 and the nozzle N changes according to the deformation of the medium 11 on the transport surface F2. For example, assuming that the curl in the circumferential direction centered on the X axis is a deformation of the medium 11, as can be understood from FIG. 2, the distance G between the landing surface F3 and the nozzle N is a plurality of nozzles arranged along the Y axis. It can be different for each of N.

In the following description, for convenience, attention will be paid to the different first nozzle N1 and the second nozzle N2 among the plurality of nozzles N arranged along the Y axis. The first nozzle N1 illustrated in FIG. 5 is one nozzle N facing a region of the medium 11 in which the deformation is sufficiently small. On the other hand, the second nozzle N2 illustrated in FIG. 6 is one nozzle N facing the region of the medium 11 where the deformation is large. As can be understood from FIGS. 5 and 6, the distance G between the second nozzle N2 and the landing surface F3 is smaller than the distance G between the first nozzle N1 and the landing surface F3. As understood from the above description, the larger the deformation of the medium 11 on the transport surface F2, the smaller the distance G between the landing surface F3 and the nozzle N.

As described above, the liquid injection head 24 moves along the X axis. Therefore, the ink ejected from the nozzle N travels in the W direction inclined with respect to the Z axis in the XZ plane. As illustrated in FIG. 5, the ink ejected from the first nozzle N1 at a specific time point T1 on the time axis travels in the W direction and finally lands at the position x1 on the landing surface F3.

As illustrated in FIG. 6, it is assumed that ink is ejected from the second nozzle N2 at the same time point T1 as the injection from the first nozzle N1 (hereinafter referred to as “inverse proportion”). The ink ejected from the second nozzle N2 travels in the W direction and finally lands at the position x2 on the landing surface F3. Since the distance G between the landing surface F3 and the second nozzle N2 is smaller than the distance G between the landing surface F3 and the first nozzle N1, the ink ejected from the second nozzle N2 was ejected from the first nozzle N1. It lands on the landing surface F3 earlier than the ink lands. Therefore, the landing position x2 is a position on the X-axis separated from the landing position x1 by an error ε. That is, an error ε occurs at the landing position x of the ink ejected from the second nozzle N2 due to the deformation of the medium 11. As understood from the above description, as the distance G between the landing surface F3 and the nozzle N decreases due to the deformation of the medium 11, the error ε of the landing position x tends to increase.

In order to reduce the error ε of the landing position x described above, the control unit 21 of the first embodiment sets the timing at which each of the plurality of nozzles N ejects ink (hereinafter referred to as “injection timing”) as the landing surface. The adjustment is made according to the distance G between F3 and the nozzle N. That is, the control unit 21 ejects ink from each nozzle N at a time according to the degree of deformation of the medium 11.

Specifically, as illustrated in FIG. 6, the control unit 21 injects ink from the second nozzle N2 at a time point T2 delayed by a delay amount τ from the time point T1 of injection by the first nozzle N1. According to the above configuration, as shown by the broken line arrow in FIG. 6, the time difference between the time when the ink ejected from the second nozzle N2 lands and the time when the ink ejected from the first nozzle N1 lands. Is reduced. Therefore, the error ε between the landing position x1 and the landing position x2 is reduced as compared with the comparative example.

As illustrated in FIG. 3, the control device 211 of the control unit 21 functions as the acquisition unit 51 and the control unit 52 by executing the program stored in the storage device 212. The acquisition unit 51 acquires shape data H regarding the shape of the medium 11. As illustrated in FIG. 7, the deformation of the medium 11 on the transport surface F2 is particularly remarkable in the region (hereinafter referred to as “first region”) A1 of the medium 11 including the front end or the rear end in the Y-axis direction. Can occur. The shape data H of the first embodiment is data representing the shape in the first region A1 of the medium 11.

The tendency of the medium 11 to be deformed depends on the type of the medium 11. In consideration of the above tendency, the acquisition unit 51 of the first embodiment acquires data representing the type of the medium 11 as the shape data H. For example, the user specifies the type of medium 11 used in the liquid injection device 100. The acquisition unit 51 generates shape data H representing the type of the medium 11 designated by the user.

The control unit 52 of FIG. 3 controls the injection of ink by the liquid injection head 24 by supplying a plurality of signals including the control signal L and the instruction signal S to the liquid injection head 24. The control unit 52 of the first embodiment can execute the first control process and the second control process. The first control process is a process executed within the period of injecting ink into the first region A1 of the medium 11 where deformation is likely to occur, and the second control process is compared with the first region A1 of the medium 11. This is a process executed within the period of injecting ink into the second region A2 of FIG. 7, which is unlikely to be deformed. The second region A2 is a region other than the first region A1.

The first control process is a process of controlling the ink injection timing by each of the plurality of nozzles N according to the shape data H acquired by the acquisition unit 51. Specifically, the control unit 52 estimates the distance G between the landing surface F3 and the nozzle N for each nozzle N from the shape data H, and controls the injection timing of each nozzle N according to the distance G. Specifically, the control unit 52 estimates the distance G between each of the plurality of nozzles N of the liquid injection head 24 and the landing surface F3 based on the shape data H acquired by the acquisition unit 51. For example, the control unit 52 searches for the interval G corresponding to the shape data H acquired by the acquisition unit 51 from the data table in which the shape data H and the interval G are associated with each other. Further, the control unit 52 may calculate the interval G by applying the shape data H acquired by the acquisition unit 51 to the mathematical formula expressing the relationship between the shape data H and the interval G. The data table or mathematical formula used for estimating the interval G is created according to the result of preliminarily investigating the tendency of the shape according to the type of the medium 11, and is stored in the storage device 212.

Further, in the first control process, the control unit 52 delays the injection timing by the delay amount τ for the nozzle N whose interval G is less than the predetermined threshold value Gth, and delays the injection timing for the nozzle N whose interval G exceeds the threshold value Gth. I won't let you. That is, in the first embodiment, the presence / absence of delay in injection timing is controlled binary according to the interval G. For example, assuming that the interval G corresponding to the second nozzle N2 is lower than the threshold value Gth as described above, the control unit 52 delays the amount of delay from the time point T1 by the first nozzle N1 as described above with reference to FIG. Ink is ejected from the second nozzle N2 at the time point T2 delayed by τ.

FIG. 8 is an explanatory diagram of an operation focusing on the first nozzle N1 and the second nozzle N2. In FIG. 8, it is assumed that the instruction signal S indicates that the same amount of ink is ejected from the first nozzle N1 and the second nozzle N2 at the same position on the x-axis.

In FIG. 8, focusing on the first unit period U1 and the second unit period U2 that are in phase with each other on the time axis, the first drive element E1 corresponding to the first nozzle N1 and the second nozzle N2 corresponding to the second nozzle N2 are shown. The drive pulse Q supplied to the two drive elements E2 is shown in the figure. The pressure chamber C corresponding to the first nozzle N1 and the first drive element E1 is an example of the "first pressure chamber", and the pressure chamber C corresponding to the second nozzle N2 and the second drive element E2 is the "second pressure chamber". This is an example of a "pressure chamber".

As illustrated in FIG. 8, in the first embodiment, the injection timing of each nozzle N is controlled in units of the unit period U defined by the control signal L. Specifically, in the first unit period U1, the supply switching unit 43 supplies the drive pulse Q to the first drive element E1 and does not supply the drive pulse Q to the second drive element E2. On the other hand, in the second unit period U2 immediately after the first unit period U1, the supply switching unit 43 does not supply the drive pulse Q to the first drive element E1 and supplies the drive pulse Q to the second drive element E2. .. The control unit 52 controls the liquid injection head 24 according to the shape data H so that the supply switching unit 43 executes the above operation. That is, in the first embodiment, the drive pulse Q is sent to the second drive element E2 when the delay amount τ corresponding to the time length of the unit period U is delayed from the time when the drive pulse Q is supplied to the first drive element E1. Be supplied. As understood from the above description, when the same amount of ink is ejected from the first nozzle N1 and the second nozzle N2 having different intervals G from the landing surface F3, the ink is ejected from the first nozzle N1 and the second nozzle N2. The control unit 52 controls the supply switching unit 43 (liquid injection head 24) so that the ink is landed at the same position on the X-axis on the medium 11. Specifically, the control unit 52 makes the supply and stop patterns of the drive pulse Q different between the first drive element E1 and the second drive element E2 according to the shape data H.

On the other hand, as described above, the second control process is executed within the period of injecting ink into the second region A2 of the medium 11 where deformation is unlikely to occur. Since deformation of the medium 11 is unlikely to occur in the second region A2, the distance G between the landing surface F3 and the nozzle N substantially matches over the plurality of nozzles N. Therefore, in the second control process, the control unit 52 controls the supply switching unit 43 (liquid injection head 24) so that the ink is ejected from the first nozzle N1 and the second nozzle N2 at the same injection timing. That is, when the same amount of ink is ejected from the first nozzle N1 and the second nozzle N2 whose distance G from the landing surface F3 is substantially the same, the ink ejected from the first nozzle N1 and the second nozzle N2 is ejected. The control unit 52 controls the supply switching unit 43 (liquid injection head 24) so as to land at the same position on the X-axis on the medium 11. That is, the control unit 52 matches the supply and stop patterns of the drive pulse Q between the first drive element E1 and the second drive element E2.

As described above, in the first embodiment, when the ink ejected from the first nozzle N1 and the second nozzle N2 is landed on the medium 11 at the same position on the X axis, the ink is applied to the first region A1 of the medium 11. The liquid injection head 24 is controlled so that the injection timing for injecting the ink is different between the first nozzle N1 and the second nozzle N2. Therefore, even in a situation where the deformation of the medium 11 is not completely eliminated by the suction by the medium support portion 25, the error ε of the landing position x can be reduced. It can be said that the suction force required for the medium support portion 25 is reduced because the error ε of the landing position x is reduced even when the suction force by the medium support portion 25 is low. Therefore, there is also an advantage that the power consumption by the medium support portion 25 is reduced.

FIG. 9 is a graph showing the distance G between each nozzle N of the liquid injection head 24 and the landing surface F3 and the error ε of the landing position x of the ink ejected from each nozzle N. The horizontal axis of FIG. 9 is the number m assigned to each nozzle N in the order of arrangement along the Y axis. Regarding the error ε in FIG. 9, the error ε in the first embodiment in which the injection timing is adjusted according to the interval G is shown by a solid line, and the error ε in the comparative example in which the injection timing is not adjusted is shown by a broken line.

As can be understood from FIG. 9, in the comparative example, an error ε corresponding to the distance G between the landing surface F3 and the nozzle N occurs. In contrast to the comparative example, in the first embodiment, the error ε of the landing position x is reduced. FIG. 9 illustrates a case where the injection timing is delayed by one unit period U for the nozzle N in the range α in which the interval G is below the threshold value Gth. Therefore, the error ε of the landing position x for each nozzle N in the range α is reduced by the numerical value corresponding to the time length of one unit period U as compared with the comparative example.

In the first embodiment, the delay amount τ is set to the time length of the unit period U. Therefore, there is an advantage that the error of the landing position can be reduced by the simple control of adjusting the presence / absence of the supply of the drive pulse Q to each drive element E for each unit period U.

In the above description, a binary control is exemplified in which the injection timing is delayed for the nozzle N whose interval G is below the threshold value Gth and the injection timing is not delayed for the nozzle N whose interval G is above the threshold value Gth. As an example of, the delay amount τ may be controlled in multiple values according to the interval G.

For example, the control unit 52 does not delay the injection timing for the nozzle N whose interval G exceeds the threshold value Gth1. Further, the control unit 52 delays the injection timing by the delay amount τ corresponding to one unit period U for the nozzle N whose interval G is a numerical value between the threshold value Gth1 and the threshold value Gth2. The threshold value Gth2 is a predetermined value lower than the threshold value Gth1. Further, the control unit 52 delays the injection timing by a delay amount τ corresponding to two unit periods U for the nozzle N whose interval G is less than the threshold value Gth2.

As understood from the above description, the configuration of the first embodiment in which the presence or absence of the delay of the injection timing is controlled in a binary manner and the above-described configuration in which the delay amount τ of the injection timing is controlled in a multivalued manner are media. It is comprehensively expressed as a configuration in which the greater the degree of deformation represented by the shape data H with respect to the first region A1 of 11, the greater the time difference between the injection timing by the first nozzle N1 and the injection timing by the second nozzle N2.

B. Second Embodiment The second embodiment will be described. In the first embodiment, the ink injection timing by each nozzle N is controlled in units of the unit period U. In the second embodiment, the injection timing is controlled in units shorter than the unit period U. For the elements having the same functions as those of the first embodiment in each of the embodiments illustrated below, the reference numerals used in the description of the first embodiment will be used and detailed description of each will be omitted as appropriate.

FIG. 10 is an explanatory diagram of the operation of the liquid injection device 100 in the second embodiment. As illustrated in FIG. 10, the drive signal D of the second embodiment includes a plurality of drive pulses Q for each unit period U defined by the control signal L. The plurality of drive pulses Q within the unit period U include the first drive pulse Q1 and the second drive pulse Q2. The first drive pulse Q1 and the second drive pulse Q2 are set at different time points within the unit period U. Specifically, the second drive pulse Q2 is set behind the first drive pulse Q1. The first drive pulse Q1 and the second drive pulse Q2 have a common waveform.

In FIG. 10, similarly to FIG. 8 described above, the first nozzle N1 and the second nozzle so that the ink ejected from the first nozzle N1 and the second nozzle N2 land at the same position on the X axis in the medium 11. It is assumed that the instruction signal S indicates that the same amount of ink is ejected from N2. Further, in the shape of the medium 11 indicated by the shape data H, the distance G between the landing surface F3 and the second nozzle N2 is smaller than the distance G between the landing surface F3 and the first nozzle N1. For example, the interval G corresponding to the second nozzle N2 is below the threshold Gth, and the interval G corresponding to the first nozzle N1 is above the threshold Gth.

In one unit period U exemplified in FIG. 10, the supply switching unit 43 supplies the first drive pulse Q1 to the first drive element E1 corresponding to the first nozzle N1 and corresponds to the second nozzle N2. The second drive pulse Q2 is supplied to the two drive elements E2. The second drive pulse Q2 is not supplied to the first drive element E1, and the first drive pulse Q1 is not supplied to the second drive element E2. The control unit 52 controls the liquid injection head 24 according to the shape data H so that the supply switching unit 43 executes the above operation.

That is, in the second embodiment, the second embodiment is delayed by a delay amount τ corresponding to the time difference between the first drive pulse Q1 and the second drive pulse Q2 from the time when the drive pulse Q is supplied to the first drive element E1. The second drive pulse Q2 is supplied to the two drive element E2. As understood from the above description, in the second embodiment as well as in the first embodiment, the ink ejected from the first nozzle N1 and the second nozzle N2 lands at the same position on the X-axis in the medium 11. As described above, when the same amount of ink is ejected from the first nozzle N1 and the second nozzle N2 having different intervals G from the landing surface F3, the supply and stop patterns of the drive pulse Q are the first drive element E1 and the first. The control unit 52 controls the supply switching unit 43 so as to differ from the two drive elements E2 according to the shape data H.

In the second embodiment, the same effect as in the first embodiment is realized. Further, in the second embodiment, since the ink injection timing by each nozzle N is controlled in units shorter than the unit period U, it is compared with the first embodiment in which the injection timing is adjusted in units of the unit period U. Therefore, there is an advantage that the error ε of the landing position x can be reduced with high accuracy.

In the above description, the first drive pulse Q1 is used for the first nozzle N1 whose interval G exceeds the threshold value Gth, and the second drive pulse Q2 is used for the second nozzle N2 whose interval G is less than the threshold value Gth. However, as in the following example, the delay amount τ may be controlled in multiple values according to the interval G. In the following description, attention will be paid to the first nozzle N1, the second nozzle N2, and the third nozzle N3, which have different intervals G from the landing surface F3. The first drive element E1 is a drive element E corresponding to the first nozzle N1, the second drive element E2 is a drive element E corresponding to the second nozzle N2, and the third drive element E3 corresponds to the third nozzle N3. It is a driving element E.

For example, as illustrated in FIG. 11, it is assumed that the drive signal D includes three drive pulses Q (Q1 to Q3) for each unit period U. The control unit 52 controls the supply switching unit 43 so that the first drive pulse Q1 is supplied to the first drive element E1 for the first nozzle N1 whose interval G exceeds the threshold value Gth1. That is, the injection timing is not delayed for the first nozzle N1 whose interval G exceeds the threshold value Gth1. Further, the control unit 52 supplies the second nozzle N2 whose interval G is a numerical value between the threshold value Gth1 and the threshold value Gth2 so that the second drive pulse Q2 is supplied to the second drive element E2. To control. That is, the injection timing of the second nozzle N2 is delayed with respect to the injection timing of the first nozzle N1 by the delay amount τ corresponding to the time difference between the first drive pulse Q1 and the second drive pulse Q2. The threshold value Gth2 is a predetermined value lower than the threshold value Gth1. Further, the control unit 52 controls the supply switching unit 43 so that the third drive pulse Q3 is supplied to the third drive element E3 for the third nozzle N3 whose interval G is less than the threshold value Gth2. That is, the injection timing of the third nozzle N3 is delayed with respect to the injection timing of the first nozzle N1 by the delay amount τ corresponding to the time difference between the first drive pulse Q1 and the third drive pulse Q3.

As can be understood from the above description, in the configuration in which any one of the plurality of drive pulses Q in the unit period U is selected according to the interval G, the degree of deformation represented by the shape data H with respect to the first region A1 of the medium 11 is determined. The larger the value, the larger the time difference between the injection timing by the first nozzle N1 and the injection timing by the second nozzle N2, which is comprehensively expressed.

C. Modification Examples Each of the above-exemplified forms can be variously transformed. Specific modifications that can be applied to each of the above-described forms are illustrated below. Two or more embodiments arbitrarily selected from the following examples can be appropriately merged to the extent that they do not contradict each other.

(1) In each of the above-described forms, the shape data H representing the type of the medium 11 is illustrated, but the information represented by the shape data H is not limited to the above examples. For example, the shape data H illustrated below may be used.

[Aspect 1]
In the configuration in which the roll paper 12 is used as in each of the above-described forms, the medium 11 tends to be more easily deformed as the remaining amount of the roll paper 12 decreases. Considering the above tendency, the acquisition unit 51 may acquire the data representing the remaining amount of the roll paper 12 as the shape data H. The remaining amount of the roll paper 12 is specified according to, for example, the past printing history or the weight of the roll paper 12. The control unit 52 estimates the distance G between the landing surface F3 and each nozzle N from the shape data H representing the remaining amount of the roll paper 12. For example, a table that defines the correspondence between the shape data H and the interval G of each nozzle N is stored in the storage device 212, and the control unit 52 specifies the interval G from the shape data H by referring to the table. The control unit 52 may estimate the interval G by applying the shape data H to the mathematical formula expressing the relationship between the shape data H and the interval G of each nozzle N. Further, the shape data H including both the type of the medium 11 and the remaining amount of the roll paper 12 may be used.

[Aspect 2]
As illustrated in FIG. 12, the detection unit 26 that detects the distance G between the landing surface F3 and each nozzle N may be installed on, for example, the liquid injection head 24. The detection unit 26 is an optical sensor including, for example, a light emitting element that irradiates the landing surface F3 with light and a light receiving element that receives the reflected light from the landing surface F3. Detect the interval G of. The acquisition unit 51 acquires shape data H representing the interval G detected by the detection unit 26. The control unit 52 adjusts the injection timing of each nozzle N according to the interval G represented by the shape data H.

According to the second aspect using the detection unit 26, since the shape data H corresponding to the result of detecting the distance between the landing surface F3 and the nozzle N is acquired, the landing is performed with high accuracy according to the actual shape of the medium 11. The error ε at the position x can be reduced. On the other hand, in the configuration of the first embodiment using the shape data H representing the type of the medium 11 or the configuration of the first embodiment using the shape data H representing the remaining amount of the roll paper 12, the detection unit 26 for detecting the interval G Is unnecessary. Therefore, according to the configuration of the first embodiment or the first embodiment, there is an advantage that the configuration of the liquid injection device 100 is simplified as compared with the second embodiment.

(2) The configuration of the first embodiment in which the injection timing is adjusted in units of the unit period U and the configuration of the second embodiment in which the injection timing is adjusted in units shorter than the unit period U may be combined. ..

(3) Some or all the elements constituting the drive circuit 40 may be installed in the control unit 21. For example, the signal generation unit 41 may be installed in the control unit 21. Further, some or all the elements constituting the control unit 21 may be installed in the drive circuit 40.

(4) FIG. 13 shows the position z1 and the position z2 of the landing surface F3 in the direction of the Z axis. The position z1 is the position of the landing surface F3 when the medium 11 is not deformed, and the position z2 is the position of the landing surface F3 when the medium 11 is separated from the transport surface F2 by the deformation. The locus Ta1 of FIG. 13 is a locus of ink ejected from the nozzle N within a period in which the liquid injection head 24 moves in the positive direction of the X-axis. The locus Ta2 is a locus of ink ejected from the nozzle N within a period in which the liquid injection head 24 moves in the negative direction of the X-axis. In a state where the landing surface F3 is at the position z1, the ink landing position x1 along the locus Ta1 and the ink landing position x2 along the locus Ta2 coincide with each other on the X-axis (hereinafter referred to as "configuration 1"). is assumed. However, in the configuration 1, there is a problem that the error ε between the landing position x1 and the landing position x2 is large when the landing surface F3 is at the position z2 due to the deformation of the medium 11.

Considering the above circumstances, as shown by the broken line in FIG. 13, when the landing surface F3 is located at the position z3 between the positions z1 and the position z2, the landing position x1 and the landing position x2 are the landing surfaces. A configuration in which the injection timing by each nozzle N is adjusted so as to coincide with each other on F3 (hereinafter referred to as “configuration 2”) is preferable. The adjustment of the injection timing is realized, for example, by the same configuration as in the first embodiment or the second embodiment.

The locus Tb1 of FIG. 13 is the locus of ink ejected from the nozzle N within the period in which the liquid injection head 24 moves in the positive direction of the X-axis in the configuration 2. The locus Tb2 of FIG. 13 is the locus of ink ejected from the nozzle N within the period in which the liquid injection head 24 moves in the negative direction of the X-axis in the configuration 2. As illustrated in FIG. 13, the ink landing position x1 along the locus Tb1 and the ink landing position x2 along the locus Tb2 coincide with each other on the landing surface F3 when the landing surface F3 is at the position z3. , When the landing surface F3 is at the position z1 or the position z2, it is deviated on the X axis. However, the amount of deviation is smaller than the error ε in the configuration 1. According to the configuration 2 illustrated above, it is possible to reduce the fluctuation range of the error ε of the landing position x as compared with the configuration 1.

(5) The liquid injection device 100 illustrated in each of the above-described embodiments can be adopted in various devices such as a facsimile machine and a copier, in addition to a device dedicated to printing. However, the application of the liquid injection device is not limited to printing. For example, a liquid injection device that injects a solution of a coloring material is used as a manufacturing device that forms a color filter for a display device such as a liquid crystal display panel. Further, a liquid injection device for injecting a solution of a conductive material is used as a manufacturing device for forming wiring and electrodes on a wiring board. Further, a liquid injection device for injecting a solution of an organic substance related to a living body is used, for example, as a manufacturing device for manufacturing a biochip.

100 ... liquid injection device, 11 ... medium, 12 ... roll paper, 13 ... liquid container, 21 ... control unit, 211 ... control device, 212 ... storage device, 22 ... transfer mechanism, 221 ... supply mechanism, 222 ... discharge mechanism, 23 ... Moving mechanism, 231 ... Conveyor, 232 ... Endless belt, 24 ... Liquid injection head, 25 ... Medium support, 251 ... Suction hole, 26 ... Detection unit, 40 ... Drive circuit, 41 ... Signal generation unit, 42 ... Signal processing unit, 43 ... Supply switching unit, 44 ... Switch, 51 ... Acquisition unit, 52 ... Control unit, C ... Pressure chamber, E ... Drive element, N ... Nozzle, F1 ... Injection surface, F2 ... Conveyance surface, F3 ... Landing surface, H ... shape data, U ... unit period, L ... control signal, S ... instruction signal, D ... drive signal, Q ... drive pulse.

Claims (11)

A transport mechanism that transports the medium along the first axis,
A medium support portion that sucks the medium transported by the transport mechanism, and
A liquid injection head in which a plurality of nozzles for injecting liquid are arranged along the first axis,
An acquisition unit that acquires shape data regarding the shape of the first region including the end portion in the direction of the first axis of the medium, and an acquisition unit.
A control unit that controls the injection of liquid by the liquid injection head is provided.
The transport mechanism transports the medium in a constant transport amount over the entire area of the medium in the direction of the first axis.
In the control unit, the timing at which the first nozzle of the plurality of nozzles injects the liquid into the first region and the second nozzle of the plurality of nozzles different from the first nozzle liquid in the first region. A liquid injection device that makes the timing of injection different depending on the shape data. The liquid injection device according to claim 1, wherein the control unit injects a liquid from the first nozzle and the second nozzle into a second region of the medium other than the first region at the same timing. The control unit claims that the greater the degree of deformation that the shape data indicates for the first region, the greater the time difference between the timing of injecting the liquid from the first nozzle and the timing of injecting the liquid from the second nozzle. The liquid injection device according to claim 1 or 2. A moving mechanism for reciprocating the liquid injection head along a second axis intersecting the first axis is provided.
When the control unit determines that the distance between the second nozzle and the medium is smaller than the distance between the first nozzle and the medium due to the deformation of the first region based on the shape data, the control unit determines. The liquid injection device according to any one of claims 1 to 3, wherein the liquid is injected from the second nozzle at a timing delayed with respect to the timing of injecting the liquid from the first nozzle. The liquid injection head
A first pressure chamber communicating with the first nozzle and
The first driving element that fluctuates the pressure of the liquid in the first pressure chamber,
A second pressure chamber communicating with the second nozzle and
A second driving element that fluctuates the pressure of the liquid in the second pressure chamber is included.
A signal generator that generates a drive signal that includes a drive pulse for each unit period,
A supply switching unit for switching between supply and stop of a drive pulse to the first drive element and the second drive element is provided.
When the control unit injects the same amount of liquid from the first nozzle and the second nozzle, the pattern of supply and stop of the drive pulse is the first drive element and the second according to the shape data. The liquid injection device according to any one of claims 1 to 4, which controls the supply switching unit so as to be different from the driving element. The supply switching unit
In the first unit period, the drive pulse is supplied to the first drive element, and the drive pulse is not supplied to the second drive element.
In the second unit period immediately after the first unit period, the control unit feeds the shape data so that the drive pulse is not supplied to the first drive element but is supplied to the second drive element. The liquid injection device according to claim 5, which controls the supply switching unit accordingly. The drive signal includes a first drive pulse and a second drive pulse for each unit period.
The supply switching unit supplies the first drive pulse to the first drive element and supplies the first drive pulse to the second drive element in one unit period according to the shape data. The liquid injection device according to claim 5, which supplies the second drive pulse without using the second drive pulse. The liquid injection device according to any one of claims 1 to 7, wherein the shape data is data representing the type of the medium. The medium is a roll of paper wound in a cylindrical shape.
The liquid injection device according to any one of claims 1 to 7, wherein the shape data is data representing the remaining amount of the roll paper. A detection unit for detecting the distance between the surface of the medium and the nozzle is provided.
The liquid injection device according to any one of claims 1 to 7, wherein the acquisition unit acquires the shape data representing the interval detected by the detection unit. A transport mechanism that transports the medium along the first axis,
A medium support portion that sucks the medium transported by the transport mechanism, and
A liquid injection head in which a plurality of nozzles for injecting liquid are arranged along the first axis,
Equipped with
The transport mechanism transports the medium in a constant transport amount over the entire area of the medium in the direction of the first axis.
It is a control method of the liquid injection device.
Obtain shape data regarding the shape of the first region of the medium including the end portion in the direction of the first axis.
The timing at which the first nozzle of the plurality of nozzles injects the liquid into the first region and the timing at which the second nozzle of the plurality of nozzles different from the first nozzle injects the liquid into the first region. A method for controlling a liquid injection device, which makes the liquid injection device different according to the shape data.

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