JP6634861B2 - Droplet ejection device - Google Patents

Description

  The present invention relates to a droplet discharge device.

  Patent Document 1 discloses a colored ink container having a capacity V1 containing a colored ink containing a solvent polymerized in the presence of an acid and a color component dispersed in the solvent, and a photoacid generator for generating an acid by light irradiation. A reaction liquid container containing a reaction liquid obtained by adding an agent to a solvent and having a volume V2 smaller than V1; a stirring container for mixing the colored ink and the reaction liquid to obtain a recording ink; A colored ink supply pump for supplying the colored ink from a container to the stirring container, a reaction liquid supply pump for supplying the reaction liquid from the reaction liquid container to the stirring container, and an inkjet for discharging the recording ink to a recording medium An ink jet recording apparatus comprising: a recording head; and a supply pipe for supplying the recording ink in the stirring container to the ink jet recording head. It is.

  Patent Document 2 discloses an ink jet printer that includes a recording head provided with nozzles for ejecting ink, and lands the ink ejected from the nozzles on a recording medium and cures the recording medium to form an image. A first ink material supply unit for supplying a first ink material to a second ink material supply unit for supplying a second ink material to the recording head; and at least one of the first ink material and the second ink material. A supply amount adjustment device that adjusts the supply amount, and a control unit that controls the supply amount adjustment device based on the type of the recording medium is provided, and the first ink material and the second ink material are mixed to mix the first ink material and the second ink material. An ink-jet printer characterized by constituting ink has been disclosed.

JP 2011-073455 A JP 2004-195852 A

  An object of the present invention is to provide a droplet discharge device in which deterioration of an infrared absorbent in a liquid supplied to a droplet discharge head is suppressed as compared with a case where a liquid is stored without cooling. It is in.

In order to achieve the above object, according to the first aspect of the present invention, there is provided a droplet discharge head for discharging a droplet from a nozzle to form an image on a recording medium, and a storage for storing a liquid containing an infrared absorbent. Means, cooling means for cooling the liquid stored in the storage means, supply means for supplying the liquid from the storage means to the droplet discharge head, and heating means for heating the liquid passing through the supply means And an irradiating means for irradiating the image formed on the recording medium with a laser beam.

  According to a second aspect of the present invention, there is provided a droplet discharge head for discharging a droplet from a nozzle to form an image on a recording medium, a first storage unit for storing a liquid containing an infrared absorbent, and A cooling means for cooling the liquid stored in the first storage means, and a second storage means for storing the liquid to be supplied from the first storage means to the droplet discharge head, the volume being smaller than the first storage means. Means, a heating means for heating the liquid stored in the second storage means, a supply means for supplying the heated liquid to the droplet discharge head, and a supply means for supplying the liquid after heating to the image formed on the recording medium. And a irradiating means for irradiating a laser beam.

  The invention according to claim 3 is the droplet discharge device according to claim 1 or 2, wherein the cooling unit cools the liquid to a first temperature or lower at which the infrared absorbent does not deteriorate.

  The invention according to claim 4 is the droplet discharge device according to any one of claims 1 to 3, wherein the cooling unit cools the liquid to 10 ° C or less.

  The invention according to claim 5, wherein the heating means heats the liquid to a second temperature or more at which the viscosity of the liquid becomes a viscosity suitable for ejection. It is a droplet discharge device described in the paragraph.

  The invention according to claim 6 is the droplet discharge device according to any one of claims 1 to 5, wherein the heating means heats the liquid to 30 ° C or higher.

  An invention according to claim 7, wherein an acquiring means for acquiring the concentration of the infrared absorbent in the liquid after being ejected from the droplet ejection head, and a concentration of the infrared absorbent acquired by the acquiring means being a predetermined threshold value And control means for controlling at least one of the cooling temperature of the liquid by the cooling means and the heating temperature of the liquid by the heating means to decrease. A droplet discharge device according to any one of the preceding claims.

  According to an eighth aspect of the present invention, when the concentration of the infrared absorbent acquired by the acquisition unit is less than a predetermined threshold, the control unit reduces the energy applied to the liquid by the heating unit. The droplet discharge device according to claim 7, wherein the control is performed in the following manner.

  According to the first aspect of the invention, the deterioration of the infrared absorbent in the liquid supplied to the droplet discharge head is suppressed as compared with the case where the liquid is stored without cooling.

  According to the second aspect of the present invention, the deterioration of the infrared absorbent in the liquid supplied to the droplet discharge head is suppressed as compared with the case where heating is performed without providing the second storage means.

  According to the third aspect of the invention, the stored liquid is cooled to a temperature at which the infrared absorbent does not deteriorate.

  According to the fourth aspect of the invention, the stored liquid is cooled to 10 ° C. or lower.

  According to the invention described in claim 5, the liquid before ejection is heated to a temperature at which the viscosity of the liquid becomes a viscosity suitable for ejection.

  According to the invention described in claim 6, the liquid before ejection is heated to 30 ° C. or higher.

  According to the seventh aspect of the invention, the concentration of the infrared absorbent in the liquid after ejection is maintained at or above a predetermined threshold.

  According to the invention described in claim 8, deterioration of the infrared absorbent in the liquid generated during heating is reduced as compared with a case where the energy applied to the liquid is not changed.

FIG. 1 is a schematic configuration diagram illustrating an example of a configuration of an ink jet recording apparatus according to an embodiment of the present invention. FIG. 1 is a schematic configuration diagram illustrating an example of a configuration of an ink supply device according to an embodiment of the present invention. FIG. 1 is a block diagram illustrating an example of an electrical configuration of an inkjet recording apparatus according to an embodiment of the present invention. It is a flowchart which shows an example of the processing procedure of "infrared absorber density | concentration adjustment processing" performed by embodiment of this invention.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. In the present embodiment, an ink jet recording apparatus that forms an image on a recording medium by discharging ink droplets will be described as an example of the droplet discharge apparatus of the present invention. Note that the droplet discharge head is referred to as an “inkjet recording head” or a “recording head”. Further, the liquid supply device is referred to as an “ink supply device”.

<Inkjet recording device>
First, an ink jet recording apparatus according to the present embodiment will be described. FIG. 1 is a schematic configuration diagram illustrating an example of a configuration of an inkjet recording apparatus according to a first embodiment of the present invention. As shown in FIG. 1, the ink jet recording apparatus 10 includes a recording head 12, a laser drying device 14, an image temperature sensor 16, an image density sensor 18, a paper feed roll 20, a take-up roll 22, a transport roll 24, and an ink supply device. 28 (only the container 30 is shown). The ink supply device 28 will be described with reference to FIGS.

  A long continuous paper P is wound around the paper feed roll 20 as a recording medium. The continuous paper P pulled out from the paper feed roll 20 is transported in the direction of the arrow A as the transport roll 24 rotates. The continuous paper P transported by the transport rolls 24 is finally wound up by the rotation of the winding rolls 22. Hereinafter, the transport direction of the continuous paper P is simply referred to as “transport direction”. The recording head 12, the laser drying device 14, the image temperature sensor 16, and the image density sensor 18 are arranged between the paper feed roll 20 and the take-up roll 22 so as to face the continuous paper P. . The laser drying device 14 is an example of an “irradiating unit”.

  In this embodiment, the recording head 12 is an inkjet recording head corresponding to each color of yellow (Y), magenta (M), cyan (C), and black (K) (hereinafter, abbreviated as “recording head”). 12Y, 12M, 12C, and 12K. The recording heads 12Y, 12M, 12C, and 12K are arranged in the order described from upstream to downstream in the transport direction. Each of the recording heads 12Y, 12M, 12C, and 12K ejects a corresponding color ink droplet from a plurality of nozzles to form a corresponding color image on a recording medium. The recording head 12 is driven by a known driving method such as a thermal method or a piezoelectric method. When it is not necessary to distinguish YMCK colors, they are collectively referred to as “recording heads 12”.

  The laser drying device 14 is disposed downstream of the recording head 12 in the transport direction. The laser drying device 14 includes a plurality of laser elements, irradiates the continuous paper P on which an image is formed by the recording head 12 with laser light from the plurality of laser elements, and ejects ink droplets of the image formed on the continuous paper P. After drying, the image is fixed on the continuous paper P.

  In the present embodiment, the ink droplets of each color of YMCK contain an infrared absorbing agent. When the continuous paper P on which an image is formed is irradiated with infrared laser light (hereinafter, simply referred to as “laser light”), the infrared absorbing agent absorbs the laser light, so that the efficiency of absorbing ink droplets with respect to laser light is improved. Then, the temperature of the ink droplet is increased and the ink droplet is dried. Here, "infrared light" is light having a longer wavelength than red light and a long wavelength of about 700 nm or more.

  The image temperature sensor 16 is disposed downstream of the laser drying device 14 in the transport direction. The image temperature sensor 16 is a sensor that detects the temperature of an image formed on the continuous paper P. Here, the “image temperature” is the temperature of the surface of the continuous paper P on which an image is formed, and is also the temperature of ink droplets ejected on the continuous paper P. As the image temperature sensor 16, a non-contact type temperature sensor is preferable. For example, a radiation thermometer that measures the intensity of infrared light or the like radiated from an object to be measured and measures the temperature of the object is used.

  The image density sensor 18 is disposed downstream of the image temperature sensor 16 in the transport direction. The image density sensor 18 is an optical reader for detecting the density of an image formed on the continuous paper P. For example, a reflection-type optical sensor that includes a light projecting unit and a light receiving unit, receives reflected light of light emitted from the light projecting unit, and measures the intensity of the reflected light is used.

  In the above-described ink jet recording apparatus, ink droplets are ejected from the recording head 12 onto the continuous paper P pulled out from the paper feed roll 20 to form an image. The continuous paper P on which the image is formed by the recording head 12 is irradiated with laser light by the laser drying device 14 to dry the ink droplets of the image formed on the continuous paper P. Next, the image temperature sensor 16 detects the temperature of the image formed on the continuous paper P, and the image density sensor 18 detects the density of the image formed on the continuous paper P. Finally, the continuous paper P on which the image is formed and dried is taken up by the take-up roll 22, and the image formation on the continuous paper P is completed.

  Further, the ink jet recording apparatus 10 includes a container 30 for storing ink. In the present embodiment, containers 30Y, 30M, 30C, and 30K are provided for each of the recording heads 12Y, 12M, 12C, and 12K. Each of the containers 30 </ b> Y, 30 </ b> M, 30 </ b> C, and 30 </ b> K stores ink of a corresponding color and supplies the stored ink to the corresponding recording head 12. When there is no need to distinguish YMCK colors, they are collectively referred to as “container 30”. Hereinafter, it is referred to as “first container 30” to distinguish it from other containers. The first container 30 is an example of a “storage unit”.

  In the present embodiment, the ink containing the infrared absorbing agent is stored in the first container 30 while being cooled by the ink supply device described below. Immediately before the supply to the recording head 12, the ink is heated, and the heated ink is supplied to the recording head 12. Infrared absorbers have poor storage stability and are particularly degraded in ink. By storing the ink containing the infrared absorbent while cooling it, deterioration of the infrared absorbent is suppressed as compared with the case where the ink is stored without cooling and supplied to the recording head 12.

<Ink supply device>
Next, the ink supply device will be described. FIG. 2 is a schematic configuration diagram illustrating an example of the configuration of the ink supply device according to the first embodiment of the present invention. As shown in FIG. 2, the ink supply device 28 includes a first container 30 for storing the ink 32 and a second container 50 for storing and heating the ink 32 to be supplied to the recording head 12. The second container 50 has a smaller volume than the first container 30. The first container 30 is an example of a “first storage unit”, and the second container 50 is an example of a “second storage unit”.

  One end of the supply pipe 60 is connected to the first container 30, and the other end is connected to the second container 50. The ink 32 in the first container 30 is supplied to the second container 50 through the supply pipe 60. The supply pipe 60 is provided with a first pump 62 for adjusting the supply amount of the ink 32.

  Further, one end of the supply pipe 68 is connected to the second container 50, and the other end is connected to the recording head 12. The ink 32 in the second container 50 is supplied to the recording head 12 through the supply pipe 68. The supply pipe 68 is provided with a third pump 70 for adjusting the supply amount of the ink 32. The supply pipe 68 is an example of a “supply unit”.

  The first container 30 that stores the ink 32 is provided with a first temperature sensor 34, a first temperature regulator 36, and a first liquid amount sensor 38. The first temperature sensor 34 detects the temperature of the ink 32 in the first container 30. The first temperature adjuster 36 adjusts the temperature of the ink 32 in the first container 30. The first liquid amount sensor 38 detects a liquid amount of the ink 32 in the first container 30. The first temperature controller 36 is an example of a “cooling unit”.

  The second container 50 that stores and heats the ink 32 is provided with a second temperature sensor 53, a second temperature regulator 54, a second liquid amount sensor 55, a viscometer 56, and a stirrer 58. The second temperature sensor 53 detects the temperature of the ink 32 in the second container 50. The second temperature adjuster 54 adjusts the temperature of the ink 32 in the second container 50. The second liquid amount sensor 55 detects the liquid amount of the ink 32 in the second container 50. The viscometer 56 measures the viscosity of the ink 32 in the second container 50. The stirrer 58 is rotationally driven by a motor to stir the ink 32 in the second container 50. The second temperature controller 54 is an example of a “heating unit”.

  The ink supply device 28 includes an ink supply device drive control unit 90 described later. Each part of the ink supply device 28 is driven and controlled by an ink supply device drive control unit 90 connected to a control unit 80 described later.

  In the ink supply device 28 described above, the temperature of the ink 32 in the first container 30 is controlled by the first temperature sensor 34 and the first temperature regulator 36 to a first temperature (for example, 10 ° C.) at which the infrared absorbent does not deteriorate. It is adjusted to. That is, the ink 32 in the first container 30 is cooled to suppress deterioration during storage. Next, the supply amount of the supply pipe 60 is adjusted by the first pump 62, and the supply amount of the supply pipe 68 is adjusted by the second pump 70. Then, the ink 32 in the first container 30 is supplied to the second container 50 at the adjusted supply amount.

  Next, the temperature of the ink 32 in the second container 50 is determined by the second temperature sensor 53 and the second temperature regulator 54 so that the viscosity of the ink 32 is suitable for ejection (hereinafter, referred to as “ejection viscosity”). Is adjusted to a second temperature (for example, 30 ° C.). That is, the ink 32 in the second container 50 is heated before being supplied to the recording head 12. By transferring the ink to the second container 50 having a smaller volume than the first container 30 and heating the ink, deterioration of the infrared absorbent is suppressed. The heating also reduces the viscosity of the ink 32 to the ejection viscosity. Then, the supply amount of the supply pipe 68 is adjusted by the second pump 70, and the ink 32 in the second container 50 is supplied to the recording head 12 at a predetermined supply amount.

  In addition, a third temperature sensor 72 and a third temperature regulator 74 are further provided in the supply pipe 68, and the temperature of the ink 32 passing through the supply pipe 68 is changed to the third temperature instead of the temperature of the ink 32 in the second container 50. The temperature may be adjusted to the second temperature (for example, 30 ° C.) by the temperature sensor 72 and the third temperature regulator 74. By heating the ink in the supply pipe 68, which is closer to the recording head 12 than the first container 30 and has a short residence time, the heating time of the ink is reduced. Further, a line mixer such as a static mixer may be inserted downstream of the third temperature controller 74 to promote stirring and mixing.

<Electrical configuration>
Next, the electrical configuration of the inkjet recording apparatus will be described.
FIG. 3 is a block diagram illustrating an example of an electrical configuration of the inkjet recording apparatus according to the first embodiment of the present invention. As shown in FIG. 3, the inkjet recording apparatus 10 includes a control unit 80 that is a computer that controls the entire apparatus and performs various operations.

  That is, the control unit 80 includes a CPU 80A, a ROM 80B, a RAM 80C, a nonvolatile memory 80D, and an input / output interface (I / O) 80E. The CPU 80A, the ROM 80B, the RAM 80C, the memory 80D, and the I / O 80E are connected to each other via a bus 80F. The CPU 80A reads out various programs stored in the ROM 80B, and executes the programs using the RAM 80C as a work area.

  The I / O 80E of the control unit 80 includes a head drive unit 82, a laser drive unit 84, a transport drive unit 86, an image temperature sensor 16, an image density sensor 18, an operation display unit 87, a communication unit 88, and an ink supply device drive control. The unit 90 is connected.

  The head driving unit 82 drives the recording head 12 according to control information from the control unit 80. That is, the head driving unit 82 forms an image on the continuous paper P by discharging ink droplets from the plurality of nozzles of the recording head 12 in accordance with the amount and timing of discharging the ink droplets for each of the plurality of nozzles. The laser driving unit 84 drives the laser drying device 14 according to control information from the control unit 80. That is, the laser driver 84 irradiates the continuous paper P on which an image is formed with laser light from the plurality of laser elements of the laser drying device 14 in accordance with the irradiation intensity and the turning-on / off timing of each of the plurality of laser elements. The transport drive unit 86 rotationally drives the plurality of transport rolls 24 to transport the continuous paper P according to control information from the control unit 80.

  The detection results of the image temperature sensor 16 and the image density sensor 18 are output to the control unit 80. The operation display unit 87 has, for example, a touch panel display on which display buttons and various information are displayed, and hardware keys such as numeric keys and a start button. With the above configuration, the operation display unit 87 receives instructions from the user and displays various information to the user. The communication unit 88 is a communication interface connected to a communication line (not shown) for transmitting and receiving communication data to and from an external device.

  The ink supply device drive control unit (hereinafter referred to as “drive control unit”) 90 is configured by a computer including a CPU and the like. The drive control unit 90 controls the driving of each unit of the ink supply device 28 according to the control information from the control unit 80. The drive control unit 90 includes a first pump 62, a first temperature sensor 34, a first temperature regulator 36, a first liquid amount sensor 38, a stirrer 58, a second pump 70, a second temperature sensor 53, and a second temperature. The regulator 54, the second liquid amount sensor 55, the viscometer 56, the third temperature sensor 72, and the third temperature regulator 74 are connected.

  The drive control unit 90 drives each of the first pump 62 and the second pump 70 according to the supply amount set by the control unit 80. The drive control section 90 drives the stirrer 58 according to the stirring speed set by the control section 80. Further, each of the first temperature sensor 34, the first liquid amount sensor 38, the second temperature sensor 53, the second liquid amount sensor 55, the viscometer 56, the third temperature sensor 72, and the third temperature controller 74 The result or the measurement result is output to the drive control unit 90 and the control unit 80.

  Here, the feedback control for setting the temperature of the ink or the like to the set temperature is executed by the drive control unit 90. The drive control unit 90 acquires the detected temperature from the first temperature sensor 34, and according to the temperature set by the control unit 80, sets the first temperature controller 36 so that the detected temperature of the first temperature sensor 34 becomes the set temperature. Drive control. Similarly, the drive control unit 90 controls the drive of the second temperature regulator 54 so that the temperature detected by the second temperature sensor 53 becomes the set temperature. Similarly, the driving of the third temperature regulator 74 is controlled such that the temperature detected by the third temperature sensor 72 becomes the set temperature.

<Infrared absorbent concentration adjustment processing>
Next, the “infrared absorbent concentration adjustment processing” will be described. Here, “the concentration of the infrared absorbent” is the concentration of the infrared absorbent in the ink after being ejected from the recording head. For example, it is the concentration of the infrared absorbent in the ink droplet ejected from the recording head onto the recording medium. In the present embodiment, an image is formed using an ink containing an infrared absorbing agent, so that the efficiency of laser light absorption when laser light is irradiated to dry ink droplets is improved.

  As described above, in the present embodiment, the ink containing the infrared absorbent is stored while being cooled, and the ink is heated immediately before being supplied to the recording head, thereby suppressing the deterioration of the infrared absorbent. I have. However, it is difficult to completely eliminate the deterioration of the infrared absorber. When the infrared absorbent deteriorates, drying of the ink droplets becomes insufficient due to a decrease in the absorption efficiency of laser light. For this reason, there is a possibility that “smudge” where the ink on the recording medium is rubbed, “offset” where the ink adheres to another recording medium or the like may occur. Therefore, by the “infrared absorbent concentration adjustment processing”, control is performed such that the concentration of the infrared absorbent in the ink droplets discharged from the recording head is maintained at or above a predetermined threshold.

  FIG. 4 is a flowchart illustrating an example of the processing procedure of the “infrared absorbent concentration adjustment processing” executed in the first embodiment of the present invention. The “infrared absorbent concentration adjustment process” is executed by the CPU 80A of the control unit 80 when the inkjet recording apparatus 10 is started up or inspected, or during image formation. In the present embodiment, the “infrared absorbent concentration adjustment process” is started in response to an execution instruction from the user via the operation display unit 87.

  First, in step 100, the recording head 12 is driven via the head driving unit 82 on the continuous paper P based on the image information of the infrared absorbent concentration adjusting image (hereinafter, referred to as “adjusting image”). To form an adjustment image. Next, in step 102, the laser drying device 14 is driven via the laser driving unit 84 to irradiate the continuous paper P on which the adjustment image is formed with laser light, and the ink of the image formed on the continuous paper P is printed. Dry the drops.

  Next, in step 104, the image temperature measured by the image temperature sensor 16 is obtained. Here, “the concentration of the infrared absorbent” is the concentration of the infrared absorbent in the ink droplets of the mixed liquid discharged from the recording head 12 onto the continuous paper P. The higher the concentration of the infrared absorber in the mixture, the higher the laser light absorption efficiency and the higher the image temperature.

  Next, in step 106, it is determined whether or not the image temperature acquired in step 104 is lower than a set value. The relationship between the image temperature and the concentration of the infrared absorbent is obtained in advance, and the image temperature when the concentration of the infrared absorbent becomes a threshold (target value) is set as a set value. That is, in step 106, it is determined whether or not the concentration of the infrared absorbent is less than the threshold. If the image temperature is lower than the set value, that is, if the concentration of the infrared absorbent is lower than the threshold, the process proceeds to step 108. On the other hand, if the image temperature is equal to or higher than the set value, that is, if the concentration of the infrared absorbing agent is equal to or higher than the threshold, the routine is terminated because there is no need to adjust.

  The threshold value of the concentration of the infrared absorbent may be set according to the type of recording medium, moisture content, reflectance, glossiness, and the like. In the case of continuous paper, the target value may be changed at the end of unwinding or winding. Further, the threshold value of the concentration of the infrared absorbent may be set according to the type of ink, such as white ink, special color ink, and general-purpose ink.

  In step 108, the concentration of the infrared absorbent in the ink droplet is calculated based on the relationship between the image temperature and the concentration of the infrared absorbent. When the image temperature is lower than the set value, the concentration of the infrared absorbent is also lower than the threshold concentration. The cause of the decrease in the concentration of the infrared absorbent is presumed to be insufficient temperature control of the ink. Therefore, in the next step 110, at least one of the set temperature (cooling temperature) of the first temperature regulator 36 and the set temperature (heating temperature) of the second temperature regulator 54 is changed so as to lower the temperature of the ink. To end the routine.

  For example, when the degree of decrease in the concentration of the infrared absorbent is small, only one of the cooling temperature and the heating temperature is decreased. The set temperature of the first temperature regulator 36 is reduced (for example, 10 ° C. → 8 ° C.) or the set temperature of the second temperature regulator 54 is reduced (for example, 30 ° C. → 28 ° C.). If the degree of decrease in the concentration of the infrared absorbent is large, both the cooling temperature and the heating temperature are decreased. It should be noted that the magnitude of the degree of the density reduction may be determined by previously setting a reference value for the amount of change from the threshold density and comparing the amount of change with the reference value.

  When the degree of decrease in the concentration of the infrared absorbent is large, control is performed so that the energy applied to the ink is further reduced. For example, the amount of liquid in the second container 50 may be reduced so that the time during which the ink is heated in the second container 50 (i.e., the residence time) is shortened. When the residence time in the second container 50 is shortened, the energy applied to the ink decreases.

  Also, instead of changing the amount of liquid in the second container 50, the set temperatures of both are changed so that the ink is heated by the third temperature regulator 74 provided in the supply pipe 68, and the second temperature is changed. The time during which the ink is heated in the container 50 (i.e., the residence time) may be reduced. In this case, for example, the set temperature of the second temperature regulator 54 is set to room temperature (for example, 25 ° C.), and the set temperature of the third temperature regulator 74 is set to the second temperature (for example, 30 ° C.). Further, the ink supply from the first container 30 may be increased by partially discharging the ink in the second container 50. An infrared absorbent dispersion may be separately added to the discharged ink, and the composition may be readjusted to be suitable for ejection.

  Each of the first temperature adjuster 36, the second temperature adjuster 54, and the third temperature adjuster 74 is driven by the drive control unit 90 in accordance with the changed set temperature or the like, so that the ink temperature adjustment is appropriate. And the concentration of the infrared absorbent converges to the target value.

  In the present embodiment, when the image temperature measured by the image temperature sensor 16 becomes lower than the set value, the set temperature of the temperature adjuster for adjusting the temperature of the ink is reset. Thus, the concentration of the infrared absorbing agent in the ink droplets ejected from the recording head 12 onto the continuous paper P is maintained at or above a predetermined threshold.

<Modification>
The configuration of the droplet discharge device described in the above embodiment is an example, and it goes without saying that the configuration may be changed without departing from the gist of the present invention.

  In the above embodiment, the ink jet recording apparatus has been described as an example of the liquid droplet discharging apparatus, but the liquid droplet discharging apparatus is not limited to the ink jet recording apparatus. Examples of the droplet discharge device include a color filter manufacturing device that manufactures a color filter by discharging ink or the like onto a film or glass, a device that forms an EL display panel by discharging an organic EL solution onto a substrate, and a dissolved state. A device for forming a bump for component mounting by discharging solder on a substrate, a device for forming a wiring pattern by discharging a liquid containing metal, and various film forming devices for forming a film by discharging a droplet. And any device that discharges droplets may be used.

  Further, in the above embodiment, the relationship between the image temperature and the concentration of the infrared absorber has been described as not changing, but when the ink performance is reduced due to deterioration of the infrared absorber and the above relationship changes, The cooling unit and the heating unit may be controlled so that the image temperature becomes a target value. When the relationship between the image temperature and the concentration of the infrared absorber changes, the image temperature may not reach the target temperature even if the concentration of the infrared absorber is set at the target concentration.

  For example, the concentration of the infrared absorbent in the ink corresponding to the measured image temperature is determined from the relationship between the initial image temperature and the concentration of the infrared absorbent. Further, from the estimated relationship between the deteriorated image temperature and the concentration of the infrared absorbing agent, the concentration of the infrared absorbing agent at which the image temperature reaches the target temperature (converging concentration) is obtained. Actually, since it is difficult to accurately estimate the relationship after deterioration, it is assumed that the correction amount ΔT of the image temperature and the correction amount ΔC of the concentration of the infrared absorbent are substantially proportional to each other, and the correction of the image temperature is performed. When the feedback control (correction, that is, the change of the temperature setting, etc.) is repeatedly performed so that the amount ΔT approaches zero, the correction amount ΔC of the concentration of the infrared absorbent also approaches zero, and the image temperature reaches the target temperature and the infrared ray absorption increases. The concentration of the absorbent converges to a convergent concentration.

REFERENCE SIGNS LIST 10 inkjet recording device 12 recording head 14 laser drying device 16 image temperature sensor 18 image density sensor 20 paper feed roll 22 take-up roll 24 transport roll 28 ink supply device 30 first container 32 ink 34 first temperature sensor 36 first temperature adjustment Device 38 first liquid amount sensor 50 second container 53 second temperature sensor 54 second temperature regulator 55 second liquid amount sensor 56 viscometer 58 stirrer 60 supply pipe 62 first pump 68 supply pipe 70 second pump 72 3 temperature sensor 74 third temperature controller 80 control unit 82 head drive unit 84 laser drive unit 86 transport drive unit 87 operation display unit 88 communication unit 90 ink supply device drive control unit (drive control unit)
P continuous paper

Claims (8)

A droplet discharge head for discharging droplets from a nozzle to form an image on a recording medium,
Storage means for storing a liquid containing an infrared absorbent,
Cooling means for cooling the liquid stored in the storage means,
Supply means for supplying the liquid from the storage means to the droplet discharge head,
Heating means for heating the liquid passing through the supply means,
Irradiating means for irradiating the image formed on the recording medium with laser light,
A droplet discharge device comprising: A droplet discharge head for discharging droplets from a nozzle to form an image on a recording medium,
First storage means for storing a liquid containing an infrared absorbent,
Cooling means for cooling the liquid stored in the first storage means;
A second storage unit having a smaller volume than the first storage unit and storing a liquid to be supplied to the droplet discharge head from the first storage unit;
Heating means for heating the liquid stored in the second storage means;
Supply means for supplying the heated liquid to the droplet discharge head,
Irradiating means for irradiating the image formed on the recording medium with laser light,
A droplet discharge device comprising:   3. The droplet discharge device according to claim 1, wherein the cooling unit cools the liquid to a temperature equal to or lower than a first temperature at which the infrared absorbent does not deteriorate. 4.   4. The droplet discharge device according to claim 1, wherein the cooling unit cools the liquid to 10 ° C. or less. 5.   5. The droplet discharge device according to claim 1, wherein the heating unit heats the liquid to a second temperature or higher at which the viscosity of the liquid becomes a viscosity suitable for discharge. 6.   The droplet discharge device according to claim 1, wherein the heating unit heats the liquid to 30 ° C. or higher. Acquisition means for acquiring the concentration of the infrared absorbent in the liquid after ejection from the droplet ejection head,
When the concentration of the infrared absorbent acquired by the acquisition unit is less than a predetermined threshold, control is performed so that at least one of the cooling temperature of the liquid by the cooling unit and the heating temperature of the liquid by the heating unit is decreased. Means,
The droplet discharge device according to any one of claims 1 to 6, further comprising:   8. The control unit according to claim 7, wherein when the concentration of the infrared absorbent acquired by the acquisition unit is less than a predetermined threshold, the control unit controls the energy imparted to the liquid by the heating unit to decrease. 9. Droplet ejection device.

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