Liquid discharge apparatus and image forming apparatus

Abstract

To suppress drying of liquid in a state where the liquid is not discharged and to suppress adhesion of dew condensation onto the nozzle surface in a state where the liquid is discharged.SOLUTION: A liquid discharge apparatus 103 includes: a liquid discharge head 10 having a nozzle surface 1a to discharge liquid; a temperature adjustment mechanism 20 to adjust temperature of the liquid discharge head; a cap 40 for covering the nozzle surface 1a; a temperature sensor 61 to detect an indoor temperature or a temperature around the nozzle surface 1a; and a controller 500 to control the temperature adjustment mechanism 20 based on the temperature detected by the temperature sensor 61.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a liquid ejection device and an image forming apparatus.

Background Art

[0002] As a liquid ejection device, there is known one including a temperature adjustment means for adjusting the temperature of a liquid to be supplied to a supply target, a detection means for detecting the temperature and humidity around the supply target, a dew point temperature derivation means for deriving a dew point temperature based on the detected temperature and humidity, and a dew condensation prevention processing means for controlling the temperature adjustment means to execute a dew condensation prevention measure by setting the temperature of the liquid to be equal to or higher than the dew point temperature (see, for example, Patent Document 1).

Summary of the Invention

Problems to be Solved by the Invention

[0003] However, in the conventional technology, when the dew point temperature is set assuming printing is in progress and the temperature of the liquid is set to be equal to or higher than the dew point temperature by the temperature adjustment means, the temperature of the liquid may become higher than the room temperature. For example, in a non-printing state where no liquid is being ejected, if the temperature of the liquid is higher than the room temperature, the liquid in the nozzle is likely to dry. For example, when the temperature of the liquid is set assuming a non-printing state, there is a possibility that dew condensation adhesion to the nozzle surface cannot be prevented during printing.

[0004] An object of the present invention is to provide a liquid ejection device capable of suppressing drying of the liquid in a state where the liquid is not ejected and suppressing dew condensation adhesion to the nozzle surface in a state where the liquid is ejected.

Means for Solving the Problems

[0005] A liquid ejection device according to an aspect of the present invention includes a liquid ejection head having a nozzle surface for ejecting a liquid, a temperature adjustment mechanism for adjusting the temperature of the liquid ejection head, a temperature sensor for detecting the room temperature or the temperature around the nozzle surface, and a control unit for controlling the temperature adjustment mechanism based on the temperature detected by the temperature sensor.

Advantages of the Invention

[0006] According to the present invention, it is possible to provide a liquid ejection device capable of suppressing drying of the liquid in a state where the liquid is not ejected and suppressing dew condensation adhesion to the nozzle surface in a state where the liquid is ejected.

Brief Description of the Drawings

[0007]

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Mode for Carrying Out the Invention

[0008] Hereinafter, a liquid ejection device according to an embodiment of the present invention will be described with reference to the drawings. In the present specification and the drawings, substantially the same components may be denoted by the same reference numerals, and redundant descriptions may be omitted.

[0009] [Liquid ejection device 103 according to the embodiment] FIG. 1 is a schematic diagram showing an example of a liquid ejection device 103 according to an embodiment of the present invention. The liquid ejection device 103 may be an image forming device that forms an image on a recording medium P. The liquid ejection device 103 includes a control unit 500, a head unit 3, an unwinder 5, a drying unit 6, and a rewinder 7. The liquid ejection device 103 includes a medium conveyance mechanism 50 that conveys the recording medium P. The medium conveyance mechanism 50 includes an unwinder 5 and a rewinder 7.

[0010] The liquid ejection device 103 ejects ink droplets onto the recording medium P to form an image. The recording medium P may be paper. The recording medium P may be, for example, roll paper. Ink is an example of liquid droplets. The conveyance direction of the recording medium P is along the longitudinal direction of the recording medium P.

[0011] The control unit 500 controls the overall operation of the liquid ejection device 103. The unwinder 5 and the rewinder 7 are synchronized by a control signal output from the control unit 500, and convey the recording medium P at a predetermined speed.

[0012] The head unit 3 includes a plurality of line heads 31 to 34. The line heads 31 to 34 are an example of a liquid ejection head. The liquid ejection device 103 may include a plurality of head units 3. The plurality of head units 3 includes a front-stage head unit 3 and a rear-stage head unit 3. The plurality of head units 3 may have the same configuration. The first-stage head unit 3 can form an image on the first surface of the recording medium P, and the second-stage head unit 3 can form an image on the second surface of the recording medium P. The first surface of the recording medium P may be the front surface, and the second surface of the recording medium P may be the back surface. "Front stage" is upstream in the conveyance of the recording medium P, and "rear stage" is downstream in the conveyance direction of the recording medium P.

[0013] The unwinder 5 is disposed upstream of the first-stage head unit 3. The rewinder 7 is disposed downstream of the second-stage head unit 3. The plurality of head units 3 are disposed between the unwinder 5 and the rewinder 7.

[0014] The medium conveyance mechanism 50 conveys the recording medium P so as to pass directly below the head unit 3. The line heads 31 to 34 eject ink based on image information, apply the ink onto the recording medium P, and form an image. The line head 31 ejects black ink, the line head 32 ejects cyan ink, the line head 33 ejects magenta ink, and the line head 34 ejects yellow ink. The colors of the ink ejected from the line heads 31 to 34 are not limited.

[0015] The drying unit 6 is a heating drum that heats the ink applied onto the recording medium P by the head unit 3 while conveying the recording medium P. The drying unit 6 can evaporate liquid components such as moisture in the ink by heating, fix the ink onto the recording medium P, and fix the image onto the recording medium P. The liquid ejection device 103 may include a plurality of drying units 6. The plurality of drying units 6 may be respectively disposed downstream of the plurality of head units 3.

[0016] The liquid ejection device 103 includes a cooling unit 65. The cooling unit 65 cools the recording medium P heated by the drying unit 6. The cooling unit 65 is provided at the subsequent stage of the drying unit 6. The first-stage cooling unit 65 is provided at the previous stage of the second-stage head unit 3. The second-stage cooling unit 65 is provided at the previous stage of the rewinder 7.

[0017] The medium conveyance mechanism 50 includes a turn bar 55. The turn bar 55 is disposed at the previous stage of the second-stage head unit 3 and reverses the front and back of the recording medium P.

[0018] The liquid ejection device 103 may include an image inspection unit. The image inspection unit reads an image fixed on the recording medium P and inspects the image. The control unit 500 receives a reception signal including image inspection data by the image inspection unit. The control unit 500 can execute various correction processes using the image inspection data.

[0019] The liquid ejection device 103 may include a pre-processing unit and a post-processing unit. The pre-processing unit may be disposed, for example, between the unwinder 5 and the head unit 3. The pre-processing unit can perform pre-processing on the recording medium P before the image is formed. The post-processing unit may be disposed, for example, between the drying unit 6 and the rewinder 7. The post-processing unit can perform post-processing on the recording medium P after the image is fixed.

[0020] The pre-processing unit can apply a processing liquid to the recording medium P, for example. The processing liquid can react with the ink to suppress bleeding. The post-processing unit may be a cooling mechanism that cools the recording medium P. The pre-processing unit and the post-processing unit may perform other processes.

[0021] [Liquid ejection head 10] Line heads 31 to 34 have a liquid ejection head 10. FIG. 2 is a perspective view showing the liquid ejection head 10. FIG. 3 is a bottom view showing the nozzle plate 1 according to the first embodiment. As shown in FIG. 2, the liquid ejection head 10 includes a nozzle plate 1, a flow path member 11, a common liquid chamber member 12, a supply port 13, and a temperature adjustment flow path 22. A plurality of pressure chambers are formed in the flow path member 11. A common liquid chamber communicating with the plurality of pressure chambers is formed in the common liquid chamber member 12. Flow paths through which ink flows are formed in the flow path member 11 and the common liquid chamber member 12.

[0022] The supply port 13 communicates with the internal flow path, the common liquid chamber, and the plurality of pressure chambers of the liquid ejection head 10. Through the supply port 13, the ink supplied into the liquid ejection head 10 flows through the flow path and the common liquid chamber and is supplied to the plurality of pressure chambers.

[0023] The ink in the pressure chamber is ejected from a nozzle N (see FIG. 3) formed in the nozzle plate 1. An actuator and a control board are mounted inside the liquid ejection head 10. The actuator includes a piezoelectric element that generates pressure in the ink in the pressure chamber. The control board applies a drive signal (voltage) to the actuator. The ink in the pressure chamber is pressurized by the actuator and ejected from the nozzle N.

[0024] A temperature adjustment flow path 22 through which a temperature adjustment liquid described later flows is connected to the liquid ejection head 10. A flow path through which the temperature adjustment liquid flows is formed inside the liquid ejection head 10. The temperature adjustment liquid that has flowed inside the liquid ejection head 10 is discharged to the outside of the liquid ejection head 10. The temperature adjustment flow path 22 may be a circulation flow path that circulates the temperature adjustment liquid.

[0025] As shown in FIG. 3, a plurality of nozzles N are formed in the nozzle plate 1. The nozzle N is a through hole that penetrates the nozzle plate 1 in the plate thickness direction. The plurality of nozzles N communicate with a plurality of pressure chambers respectively. The nozzle plate 1 includes a nozzle surface 1a on which the plurality of nozzles N are formed. The nozzle surface 1a is a surface facing the recording medium P. The nozzle surface 1a is a surface that contacts the outside of the liquid ejection head 10. A nozzle row is formed on the nozzle surface 1a. The nozzle row includes a plurality of nozzles N arranged in the Y-axis direction.

[0026] [Temperature adjustment mechanism 20] Next, the temperature adjustment mechanism 20 will be described. FIG. 4 is a schematic diagram showing the liquid ejection head 10 and the temperature adjustment mechanism 20, and is a diagram showing a state in which ink 19 is being ejected from the liquid ejection head 10. FIG. 5 is a schematic diagram showing the liquid ejection head 10, the temperature adjustment mechanism 20, and the cap 40, and is a diagram showing a state in which the cap 40 covers the nozzle surface 1a. As shown in FIGS. 1, 4, and 5, the liquid ejection device 103 includes a temperature adjustment mechanism 20 that adjusts the temperature of the liquid ejection head 10.

[0027] The temperature adjustment mechanism 20 may adjust the temperature of the liquid ejection head 10 by heating the liquid ejection head 10, or may adjust the temperature of the liquid ejection head 10 by cooling the liquid ejection head 10. The temperature adjustment mechanism 20 can adjust the temperature of the liquid ejection head 10 by exchanging heat between the liquid ejection head 10 and the temperature adjustment fluid through the temperature adjustment fluid. The temperature adjustment mechanism 20 can adjust the temperature of the nozzle surface 1a of the liquid ejection head 10. The temperature adjustment fluid may be a liquid or a gas. The temperature adjustment fluid may be a refrigerant. The temperature adjustment liquid may sometimes be referred to as the temperature adjustment fluid.

[0028] The temperature adjustment mechanism 20 includes a temperature adjustment flow path 22. The temperature adjustment flow path 22 is a flow path through which the temperature adjustment liquid flows. The temperature adjustment flow path 22 is formed by, for example, piping, pipes, grooves, and openings. As shown in FIGS. 4 and 5, a part of the temperature adjustment flow path 22 is formed inside the liquid ejection head 10. The temperature adjustment flow path 22 may be formed so as to pass through the back side of the nozzle plate 1. The back side of the nozzle plate 1 is the surface on the opposite side of the nozzle surface 1a in the plate thickness direction. The temperature adjustment liquid is a liquid different from the ink. The temperature adjustment flow path 22 may be formed so as to pass through the inside of a plurality of liquid ejection heads 10. The temperature adjustment liquid flowing through the temperature adjustment flow path 22 can adjust the temperature of the nozzle plate 1 by exchanging heat with the nozzle plate 1. The temperature adjustment mechanism 20 includes a circulation flow path for circulating the temperature adjustment liquid.

[0029] As shown in FIG. 1, the temperature adjustment mechanism 20 has a chiller (cooler) 23. The chiller 23 adjusts the temperature of the temperature adjustment liquid by exchanging heat with the temperature adjustment liquid. The chiller 23 can cool the temperature adjustment liquid.

[0030] The temperature adjustment mechanism 20 may include, for example, a tank, a pump, a flow rate adjustment valve, and a heat exchanger. The tank stores the temperature adjustment liquid. The pump moves the temperature adjustment liquid. The flow rate adjustment valve can adjust the flow rate of the temperature adjustment liquid. The heat exchanger can cool or heat the temperature adjustment liquid by exchanging heat with the temperature adjustment liquid.

[0031] [Cap 40] Next, the cap 40 will be described. As shown in FIG. 5, the liquid ejection device 103 includes a cap 40 that covers the nozzle surface 1a of the liquid ejection head 10. In FIG. 5, the cap 40 covers the nozzle surface 1a. The cap 40 forms a recess that depresses downward so as to form a space between the cap 40 and the nozzle surface 1a. The cap 40 has, for example, a bottom plate 41 and a plurality of side plates 42. In a state where the cap 40 covers the nozzle surface 1a, the bottom plate 41 is arranged apart from the nozzle surface 1a.

[0032] The plurality of side plates 42 are formed so as to surround the bottom plate 41. The plurality of side plates 42 may be arranged inclined with respect to the vertical direction. The lower ends of the plurality of side plates 42 are connected to the bottom plate 41. The upper ends of the plurality of side plates 42 are arranged so as to form the opening of the cap 40. In a state where the cap 40 covers the nozzle surface 1a, the upper ends of the plurality of side plates 42 are in contact with the bottom surface 3b of the head unit 3. In a state where the cap 40 covers the nozzle surface 1a, the upper ends of the plurality of side plates 42 are arranged so as to surround the nozzle surface 1a.

[0033] The cap 40 may cover the nozzle surface 1a of one liquid ejection head 10, or may collectively cover the plurality of nozzle surfaces 1a of the plurality of liquid ejection heads 10.

[0034] The liquid ejection device 103 may include a cap opening / closing mechanism for opening and closing the cap 40. The cap opening / closing mechanism has, for example, a hinge, a rotating shaft, an actuator, a power transmission mechanism, etc. The actuator may be, for example, a motor or a cylinder. The power transmission mechanism may include gears, belts, etc. The cap opening / closing mechanism may open and close the cap 40 by moving the cap 40 with respect to the nozzle surface 1a. The open state of the cap 40 is a state where the cap 40 does not cover the nozzle surface 1a, and the closed state of the cap 40 is a state where the cap 40 covers the nozzle surface 1a. As shown in FIG. 5, the state where the cap 40 covers the nozzle surface 1a may be described as "during capping".

[0035] The cap opening / closing mechanism may cover the nozzle surface 1a with the cap 40 by moving the liquid ejection head 10 with respect to the cap 40. The cap opening / closing mechanism may open and close the cap 40 by swinging the cap 40 around the rotating shaft. The cap opening / closing mechanism may open and close the cap 40 by moving the cap 40 in the vertical direction. The cap opening / closing mechanism can open and close the cap 40 by relatively moving the cap 40 with respect to the nozzle surface 1a.

[0036] When the liquid ejection device 103 ejects the ink 19, the cap 40 is in an open state. When the liquid ejection device 103 does not eject the ink 19, the cap 40 is in a closed state, and the nozzle surface 1a can be covered by the cap 40. In the liquid ejection device 103, by covering the nozzle surface 1a with the cap 40, drying of the ink 19 in the nozzle N can be suppressed.

[0037] [Wetting liquid 45] The liquid ejection device 103 can store the wetting liquid 45 inside the cap 40. When the cap 40 covers the nozzle surface 1a, the cap 40 is filled with the wetting liquid 45. The wetting liquid 45 can wet the inside of the cap 40 and the nozzle N. The wetting liquid 45 can suppress drying inside the cap 40 and the nozzle N. A part of the wetting liquid 45 evaporates inside the cap 40 and can wet the nozzle surface 1a and the inside of the nozzle N. The wetting liquid 45 may be any liquid as long as it can suppress drying of the ink inside the nozzle N.

[0038] The liquid ejection device 103 may include a tank for storing the wetting liquid 45, a pipe (flow path) for transferring the wetting liquid 45, a pump, and the like. In the liquid ejection device 103, the nozzle surface 1a may be covered with the cap 40 that is not filled with the wetting liquid 45.

[0039] [Hardware configuration of the liquid ejection device 103] Next, the hardware configuration of the liquid ejection device 103 will be described. FIG. 6 is a block diagram showing an example of the hardware configuration of the liquid ejection device 103 according to an embodiment of the present invention. The liquid ejection device 103 includes a control device 510 having a control unit 500.

[0040] A printer driver 515 is connected to the control unit 500. The printer driver 515 generates print data. The printer driver 515 may generate print data in a host device such as an information processing terminal like a PC (Personal Computer), an image reading device such as an image scanner, or an imaging device such as a digital camera. The printer driver 515 generates dot pattern data for image output in the liquid ejection device 103.

[0041] [Control Unit 500] The control unit 500 includes a CPU (Central Processing Unit) 501, a ROM (Read Only Memory) 502, a RAM (Random Access Memory) 503, and an NVRAM (Non-Volatile Random Access Memory) 504.

[0042] The CPU 501 is an arithmetic unit that controls the operation of the entire liquid ejection device 103. The CPU 501 controls the conveyance operation of the recording medium P and the printing operation (liquid ejection operation) by the liquid ejection head 10. The ROM 502 is a read-only non-volatile storage medium. The ROM 502 stores programs such as firmware. The RAM 503 is a volatile storage medium that enables high-speed reading and writing of information. The RAM 503 is used as a work area when the CPU 501 processes information.

[0043] The NVRAM 504 is a non-volatile storage medium that enables reading and writing of information. The NVRAM 504 stores an OS (Operating System), various control programs, application programs, etc.

[0044] The program stored in the storage unit is read into the RAM 503, and the CPU 501 performs arithmetic operations according to the program loaded into the RAM 503, thereby constituting a software control unit. The storage unit includes the ROM 502 and the NVRAM 504. The storage unit may include a storage medium such as an optical disk.

[0045] A functional block that realizes the functions of the liquid ejection device 103 is configured by a combination of hardware and a software control unit. The CPU 501 and the RAM 503 function as various control units as shown in FIG. 7. The various control units will be described later.

[0046] [Operation panel 516] The liquid ejection device 103 includes an operation panel 516. The operation panel 516 is connected to the control unit 500. The operation panel 516 is an input unit that can be operated by a user for input. The operation panel 516 may be, for example, a liquid crystal panel. The user can operate the operation panel 516 to change the setting of the printing conditions. Also, the user can operate the operation panel 516 to change the setting of various conditions.

[0047] The user can operate the operation panel 516 to input information regarding the recording medium P. The user can operate the operation panel 516 to input, for example, whether the recording medium P is blank or not. The information input via the operation panel 516 is transmitted to the control unit 500. The operation panel 516 may be the display unit and the input unit of a terminal (PC) connected to the control unit 500.

[0048] [Temperature sensor 61] The liquid ejection device 103 includes a temperature sensor 61. The temperature sensor 61 is electrically connected to the control unit 500. The temperature sensor 61 detects the temperature of the room in which the liquid ejection device 103 is installed. The temperature sensor 61 may be installed, for example, on the outer surface of the housing of the liquid ejection device 103. The temperature sensor 61 may be arranged at a position away from the housing of the liquid ejection device 103. The temperature sensor 61 can detect the temperature of the external environment of the liquid ejection device 103. The liquid ejection device 103 may receive data regarding the room temperature from a temperature sensor installed outside the device.

[0049] The liquid ejection device 103 may include a temperature sensor 61 that detects the temperature of the air around the nozzle surface 1a instead of the temperature sensor 61 that detects the room temperature. The temperature sensor 61 may be installed on the nozzle surface 1a, for example. The liquid ejection device 103 may include a temperature sensor 61 that detects the temperature of the nozzle surface 1a. The temperature data detected by the temperature sensor 61 may be temperature data that can determine whether dew condensation occurs on the nozzle surface 1a.

[0050] [Humidity sensor 62] The liquid ejection device 103 includes a humidity sensor 62. The humidity sensor 62 is electrically connected to the control unit 500. The humidity sensor 62 detects the humidity in the vicinity of the liquid ejection head 10. The humidity sensor 62 detects the humidity in the vicinity of the nozzle surface 1a, for example. The humidity sensor 62 detects the humidity inside the housing of the liquid ejection device 103. The humidity data detected by the humidity sensor 62 may be humidity data that can determine whether dew condensation occurs on the nozzle surface 1a.

[0051] The liquid ejection device 103 may include a sensor capable of detecting other data. The liquid ejection device 103 may include a sensor that detects the temperature of the liquid ejection head 10. The liquid ejection device 103 may include a sensor that detects the temperature of the fluid for temperature adjustment of the temperature adjustment mechanism 20. The liquid ejection device 103 may include a sensor that detects the color and density of the image formed on the recording medium P.

[0052] [Head control unit 521] The control unit 500 includes a head control unit 521 that controls the driving of the liquid ejection head 10. The head control unit 521 can control the operation of the head driver 17 for driving the liquid ejection head 10. The head driver 17 is mounted on the head unit 3 and is electrically connected to the liquid ejection head 10. The head driver 17 is also called a driver IC. The head control unit 521 can control the driving elements of the liquid ejection head 10 to execute liquid ejection. The head control unit 521 can execute various controls related to the liquid ejection head 10.

[0053] The head control unit 521 includes a drive signal generation unit that generates a drive signal for controlling the drive of the liquid ejection head 10, and a data transfer unit that transfers the drive signal to the head driver 17.

[0054] The control unit 500 transfers the processed image data from the head control unit 521 to the head driver 17.

[0055] The head control unit 521 can transfer the above-described image data as serial data. The head control unit 521 may transfer a transfer clock signal necessary for the transfer and confirmation of the transfer of the image data to the head driver 17. The head control unit 521 can output a latch signal and a control signal for controlling the ejection of the liquid to the head driver 17.

[0056] The drive signal generation unit of the head control unit 521 includes a D / A converter, a voltage amplifier, and a current amplifier. The D / A converter can perform D / A conversion on the pattern data of the drive pulses stored in the ROM 502, for example. The drive pulses are included in the drive signal. The voltage amplifier can amplify the voltage based on the drive pulses, for example. The current amplifier may amplify the current based on the drive pulses. The drive signal generation unit outputs a drive signal composed of one drive pulse or a plurality of drive pulses to the head driver 17.

[0057] The head driver 17 supplies a voltage based on the drive pulses to the piezoelectric element to eject the liquid from the liquid ejection head 10. The head control unit 521 can divide and eject dots of different sizes, such as large dots, medium dots, and small dots, by selecting the drive pulses.

[0058] [Motor drive unit 522] The liquid ejection device 103 has a plurality of motors 51 to 53. The medium conveyance mechanism 50 has a plurality of motors 51 to 53. The motor 51 may be a motor that drives the unwinder 5. The motor 52 may be a motor that drives the conveyance roller. The motor 53 may be a motor that drives the rewinder 7. The liquid ejection device 103 may include a motor for opening and closing the cap 40.

[0059] The control unit 500 includes a motor drive unit 522. The motor drive unit 522 controls the driving of a plurality of motors 51 to 53. The motor drive unit 522 may control the driving of other motors. The motor drive unit 522 controls the driving of a plurality of motors 51 to 53 according to a command from the CPU 501.

[0060] The motor drive unit 522 controls the rotation and stop of various motors. The motor drive unit 522 can control the conveyance of the recording medium P by controlling the rotation and stop of a plurality of motors 51 to 53. The motor drive unit 522 can control the conveyance speed of the recording medium P by controlling the rotation and stop of a plurality of motors 51 to 53.

[0061] [Temperature adjustment mechanism drive unit 523] The control unit 500 includes a temperature adjustment mechanism drive unit 523. The temperature adjustment mechanism drive unit 523 can control the operation of the temperature adjustment mechanism 20. The temperature adjustment mechanism drive unit 523 may control, for example, the driving of a pump that transfers a fluid for temperature adjustment.

[0062] [Drying drive unit 524] The control unit 500 includes a drying drive unit 524. The drying drive unit 524 can control the operation of the drying unit 6. The drying drive unit 524 may control the temperature of the heater of the drying unit 6.

[0063] [Functional configuration] Next, the functional configuration of the control unit 500 will be described. FIG. 7 is a functional block diagram of the control unit 500 according to an embodiment of the present invention. The CPU 501 shown in FIG. 6 executes a program stored in a storage unit 570 such as the ROM 502, thereby realizing the functions of the system control unit 531, memory control unit 532, communication control unit 533, ejection control unit 534, operation mode setting unit 535, drying temperature control unit 541, conveyance speed control unit 542, temperature adjustment mechanism temperature control unit 543, and storage unit 570 shown in FIG. 7. Note that external devices and sensors connected to the control unit 500 may execute a part of these functions.

[0064] The system control unit 531 controls the overall operation of the liquid ejection device 103. The memory control unit 532 controls the operation of memories such as the ROM 502, RAM 503, and NVRAM 504. The communication control unit 533 performs communication control with external devices connected to the control device 510.

[0065] The ejection control unit 534 controls the ejection of liquid by the liquid ejection head 10. Controls the operation of the liquid ejection head 10.

[0066] The operation mode setting unit 535 can set the operation mode in the liquid ejection device 103. The liquid ejection device 103 can execute a plurality of operation modes. The operation mode setting unit 535 can execute different operation modes by changing the setting of the operation mode. The operation mode may include a printing mode. The printing mode may be an image quality formation mode. The liquid ejection device 103 may change the operation mode according to, for example, the type of the recording medium P. The liquid ejection device 103 may change various settings by changing the operation mode. The liquid ejection device 103 can change the settings in the temperature adjustment mechanism 20, the medium conveyance mechanism 50, and the drying unit 6 by changing the operation mode.

[0067] The plurality of operation modes may include a liquid ejection mode and a moisturizing mode. The liquid ejection mode may be a printing mode capable of ejecting ink from the liquid ejection head 10 to perform printing. The liquid ejection mode may include a state in which preparations before printing are being executed and a state in which post-processing after printing is being executed. The liquid ejection mode may include a state in which the recording medium P is being conveyed. The liquid ejection mode may include a state in which the drying unit 6 is heated to a predetermined temperature.

[0068] The operation mode setting unit 535 may set the operation mode based on an operation input by the user. For example, when an operation input prompting the user to start printing is detected, the operation mode may be switched to the liquid ejection mode. The operation mode setting unit 535 may set the period after the timing when an operation input prompting the start of printing is detected as the liquid ejection mode.

[0069] The moisturizing mode is an operation mode in which printing is not performed, and may be an operation mode capable of moisturizing the ink in the nozzles N by covering the nozzle surface 1a with the cap 40. The moisturizing mode is an example of a case where the ejection operation is not performed for a certain period of time.

[0070] The plurality of operation modes may include a maintenance mode. The maintenance mode may be an operation mode that performs an operation to maintain or restore the functions of the liquid ejection head 10. The maintenance mode may include an operation mode that performs an operation of ejecting ink that does not contribute to printing (idle ejection operation) from the nozzles N. The maintenance mode may include an operation mode that performs an operation of sucking and removing the ink in the nozzles N. The maintenance mode may include an operation mode that performs a wiping operation of wiping foreign matter (ink droplets) adhering to the nozzle surface 1a.

[0071] The drying temperature control unit 541 controls the set temperature in the drying unit 6. The drying unit 6 can heat the recording medium P so that the temperature of the recording medium P becomes the set temperature.

[0072] The conveyance speed control unit 542 can set the conveyance speed of the recording medium P by the medium conveyance mechanism 50. For example, the motor drive unit 522 can control the driving of the plurality of motors 51 to 53 so as to achieve the set conveyance speed. The conveyance speed control unit 542 can control the conveyance speed in the unwinder 5, the conveyance speed in the rewinder 7, and the conveyance speed by the conveyance rollers.

[0073] The temperature control unit 543 of the temperature adjustment mechanism controls the set temperature in the temperature adjustment mechanism 20. The temperature adjustment mechanism 20 can heat the liquid ejection head 10 so that the nozzle surface 1a of the liquid ejection head 10 reaches the set temperature. The temperature control unit 543 of the temperature adjustment mechanism may control the set temperature in the temperature adjustment mechanism 20 so that the temperature of the nozzle surface 1a is equal to or higher than the dew point temperature during printing. The temperature control unit 543 of the temperature adjustment mechanism can set the set temperature in the temperature adjustment mechanism 20 to a temperature different from that during printing when not printing. The temperature adjustment mechanism 20 can change the temperature of the temperature adjustment fluid according to the set temperature set by the temperature control unit 543 of the temperature adjustment mechanism. The set temperature in the temperature adjustment mechanism 20 may be a temperature set based on the temperature of the temperature adjustment liquid, a temperature set based on the temperature of the nozzle surface 1a, or a temperature set based on the heater of the temperature adjustment mechanism 20. The set temperature in the temperature adjustment mechanism 20 may be a temperature set based on whether condensation occurs on the nozzle surface 1a.

[0074] The set temperature in the temperature adjustment mechanism 20 may be a temperature set based on the ink temperature or a temperature set based on the head temperature (the temperature of the liquid ejection head 10). The purpose of the temperature adjustment of the liquid ejection head 10 by the temperature adjustment mechanism 20 is to suppress the increase in the ink temperature in the liquid chamber inside the liquid ejection head 10 and the decrease in the ink viscosity due to the temperature rise during the driving of the liquid ejection head 10. In the liquid ejection head 10, a thermistor (temperature sensor) for measuring the ink temperature in the liquid chamber is provided. This thermistor is provided near the liquid chamber. The control unit 500 can calculate the ink temperature in the liquid chamber based on the measurement value by the thermistor near the liquid chamber. The set temperature in the temperature adjustment mechanism 20 may be a temperature set based on the ink temperature in the liquid chamber.

[0075] The temperature control unit 543 of the temperature adjustment mechanism can control the set temperature in the temperature adjustment mechanism 20 based on the room temperature detected by the temperature sensor 61. The temperature control unit 543 of the temperature adjustment mechanism can control the set temperature in the temperature adjustment mechanism 20 based on the humidity detected by the humidity sensor 62. The temperature control unit 543 of the temperature adjustment mechanism can control the set temperature based on data of both the room temperature and humidity.

[0076] The temperature control unit 543 of the temperature adjustment mechanism can adjust the set temperature in the temperature adjustment mechanism 20 based on the type of the recording medium P. The temperature control unit 543 of the temperature adjustment mechanism may detect the type of the recording medium P by detecting the tray in which the recording medium P is stored. The temperature control unit 543 of the temperature adjustment mechanism may determine the type of the recording medium P according to the user's operation input. The temperature control unit 543 of the temperature adjustment mechanism may determine the type of the recording medium P based on other information. The temperature control unit 543 of the temperature adjustment mechanism can change the set temperature based on the thickness of the recording medium P. For example, since the heat capacity varies depending on the thickness of the recording medium P, the dew condensation tendency on the nozzle surface 1a varies depending on the thickness of the recording medium P.

[0077] Also, the temperature control unit 543 of the temperature adjustment mechanism may adjust the set temperature in the temperature adjustment mechanism 20 based on the smoothness of the surface of the recording medium P. Generally, since friction occurs between the turn bar used when inverting the front and back of the paper and the paper, the paper temperature during backside printing becomes high for paper with a large friction coefficient when contacting the turn bar. When printing on paper with a large friction coefficient, dew condensation is more likely to occur on the nozzle surface 1a during backside printing compared to when printing on paper with a small friction coefficient. In the liquid ejection device 103, the higher the friction coefficient when contacting the turn bar, the higher the set temperature in the temperature adjustment mechanism 20 may be set.

[0078] When the friction coefficient between the turn bar used when inverting the recording medium P and the recording medium is large, the control unit 500 may control the operation by the temperature adjustment mechanism 20 so that the temperature of the liquid ejection head 10 becomes higher than when the friction coefficient between the turn bar and the recording medium is small.

[0079] The temperature control unit 543 of the temperature adjustment mechanism can control the set temperature in the temperature adjustment mechanism 20 based on the temperature detected by the room temperature sensor 61 and the operation mode. The temperature control unit 543 of the temperature adjustment mechanism can control the set temperature in the temperature adjustment mechanism 20 based on the conveyance speed of the recording medium P. The conveyance speed may be, for example, the conveyance speed of the recording medium P when passing directly below the nozzle surface 1a.

[0080] The temperature control unit 543 of the temperature adjustment mechanism may control the set temperature in the temperature adjustment mechanism 20 so as to cool the temperature of the liquid ejection head 10 as much as possible while suppressing dew condensation adhesion to the nozzle surface 1a during printing. The temperature adjustment mechanism 20 can adjust the temperature of the ink not only on the nozzle surface 1a but also inside the liquid ejection head 10. The temperature control unit 543 of the temperature adjustment mechanism may control the set temperature in the temperature adjustment mechanism 20 so as not to warm the ink in the nozzle N as much as possible while suppressing dew condensation adhesion to the nozzle surface 1a during non-printing. Non-printing may include during capping. The temperature control unit 543 of the temperature adjustment mechanism may stop the operation of the temperature adjustment mechanism 20 during non-printing.

[0081] [Storage unit 570] The storage unit 570 stores various types of information. The storage unit 570 can store information regarding various settings. The storage unit 570 may store, for example, the set temperature corresponding to the operation mode and the set conditions. The storage unit 570 can store information regarding the dew point temperature. The storage unit 570 can store a derivation formula for deriving the set temperature in the temperature adjustment mechanism 20. The storage unit 570 may store data indicating the relationship between the humidity of the air around the nozzle surface 1a, the temperature of the air around the nozzle surface 1a, and the temperature of the nozzle surface 1a. The storage unit 570 may store data regarding the ease of dew condensation adhesion to the nozzle surface 1a. The data regarding the ease of dew condensation adhesion to the nozzle surface 1a includes experimental results and simulation results.

[0082] [Printing operation] Before executing the printing operation on the recording medium P, the control unit 500 performs temperature control of the drying unit 6 so that the drying unit 6 reaches a predetermined temperature. The control unit 500 performs conveyance control of the recording medium P in the medium conveyance mechanism 50 so as to match the timing when the printing preparation by the drying unit 6 is completed.

[0083] The control unit 500 determines whether the printing start condition is satisfied. The printing start condition may be that the conveyance speed of the recording medium P is constant and the temperature of the drying unit 6 is within a predetermined range. When the printing start condition is satisfied, the ejection control unit 534 of the control unit 500 outputs an ejection signal to the liquid ejection head 10. The liquid ejection head 10 ejects ink based on the ejection signal to form an image on the recording medium P.

[0084] The temperature control unit 543 of the temperature adjustment mechanism can adjust the viscosity of the ink by controlling the temperature of the liquid ejection head 10. The temperature adjustment mechanism 20 can adjust the temperature of the liquid ejection head 10 by supplying the temperature-adjusted temperature adjustment liquid to the liquid ejection head 10. The temperature control unit 543 of the temperature adjustment mechanism can control the set temperature of the chiller 23 in the temperature adjustment mechanism 20.

[0085] [Temperature of the temperature adjustment liquid according to the printing mode] In the printing mode (image formation mode), the temperature of the temperature adjustment liquid is set in consideration of the image quality formed on the recording medium P. The control unit 500 may improve the image quality by setting the temperature of the temperature adjustment liquid to be low. When driving the liquid ejection head 10, the liquid ejection head 10 is heated up and the viscosity of the ink decreases. If the viscosity of the ink decreases, the image quality may deteriorate. The control unit 500 can adjust the viscosity of the ink by lowering the temperature of the temperature adjustment liquid and suppress the deterioration of the image quality.

[0086] In the printing mode, the temperature of the temperature adjustment liquid may be set in consideration of dew condensation on the nozzle surface 1a. The temperature control unit 543 of the temperature adjustment mechanism can control the set temperature in the temperature adjustment mechanism 20 to be equal to or higher than a predetermined temperature in consideration of dew condensation on the nozzle surface 1a. The temperature control unit 543 of the temperature adjustment mechanism can set the temperature at which dew condensation does not occur on the nozzle surface 1a in the printing mode. The temperature control unit 543 of the temperature adjustment mechanism can control the set temperature in the temperature adjustment mechanism 20 in consideration of the image quality and dew condensation in the printing mode.

[0087] [Dew condensation on the nozzle surface 1a] Dew condensation on the nozzle surface 1a is a phenomenon in which dew condensation adheres to the nozzle surface 1a when the amount of water vapor in the air around the nozzle surface 1a exceeds the saturated water vapor amount of the air around the nozzle surface 1a. The "air around the nozzle surface 1a" may be described as the "nozzle surface atmosphere". Dew condensation on the nozzle surface 1a is likely to occur when "the humidity of the nozzle surface atmosphere is high" and "the temperature of the nozzle surface 1a is low relative to the temperature of the nozzle surface atmosphere". When the humidity of the nozzle surface atmosphere is high, dew condensation is more likely to occur compared to when the humidity is low, and when the temperature of the nozzle surface 1a is low, dew condensation is more likely to occur compared to when the temperature is high. The ease of adhesion of dew condensation to the nozzle surface 1a is affected by the humidity of the air around the nozzle surface 1a, the temperature of the air around the nozzle surface 1a, and the temperature of the nozzle surface 1a.

[0088] For example, during printing as shown in FIG. 4, the humidity of the air around the nozzle surface 1a increases due to ink mist that separates from the ink 19 ejected from the nozzle N and floats in the air. Also, during printing, since the recording medium P to which the ink 19 ejected from the upstream liquid ejection head 10 adheres is being conveyed, the humidity of the air around the nozzle surface 1a above the recording medium P increases. Further, since the ink mist that separates from the ink 19 ejected from the upstream liquid ejection head 10 and floats flows downstream, the humidity of the downstream air increases.

[0089] When the temperature of the nozzle surface 1a is adjusted by the temperature adjustment mechanism 20, the temperature of the nozzle surface 1a may become lower than the temperature of the air around the nozzle surface 1a. In this case, there is a risk of dew condensation occurring on the nozzle surface 1a.

[0090] When dew condensation occurs on the nozzle surface 1a, it may cause problems in image formation on the recording medium P. Also, when dew condensation occurs on the nozzle surface 1a, there is a risk of dirt adhering to the recording medium P.

[0091] [Humidification of the nozzle surface 1a by the cap 40] As shown in FIG. 5, when the nozzle surface 1a is covered by the cap 40, humidification of the nozzle surface 1a is maintained. During such capping, the humidity of the air around the nozzle surface 1a is kept high. The humidity of the air inside the cap 40 has increased.

[0092] [Atmospheric humidity around the nozzle surface during printing] The ambient humidity of the nozzle surface during printing is affected by the ink adhesion amount and the indoor humidity. The "ink adhesion amount" refers to the amount of ink per unit area adhering to the recording medium P, and it may be the maximum adhesion amount. When the ink adhesion amount is large, the ambient humidity of the nozzle surface is higher compared to when the ink adhesion amount is small, and dew condensation is likely to adhere to the nozzle surface 1a. The maximum adhesion amount varies depending on the printing mode. In the liquid ejection device 103, the maximum adhesion amount for each printing mode is set. This maximum adhesion amount may be determined based on the drying limit, which is the limit value at which the ink adhering to the recording medium P can be dried. If ink exceeding the maximum adhesion amount adheres to the recording medium P, the roller contacting the recording medium P will be soiled due to insufficient drying of the ink. Therefore, in the liquid ejection device 103, the amount of ink adhering to the recording medium P is limited. The "maximum adhesion amount" may be the "limiting adhesion amount" or the "adhesion amount limit value". The "ink adhesion amount" may be the "printing coverage".

[0093] When the humidity of the environment where the liquid ejection device 103 is installed is high, the ambient humidity of the nozzle surface is higher compared to when the humidity of this environment is low, and dew condensation is likely to adhere to the nozzle surface 1a. The "environment where the liquid ejection device 103 is set" may be described as the "device installation environment". Generally, the degree of influence of the humidity of the device installation environment on the ease of dew condensation adhesion is smaller compared to the degree of influence by the above ink adhesion amount. The degree of influence of the humidity of the device installation environment on the ease of dew condensation adhesion varies depending on the outside air exchange rate. The "outside air exchange rate" is proportional to, for example, the flow rate of air flowing into the housing of the liquid ejection device 103 per unit time. The outside air is the air outside the housing of the liquid ejection device 103. The degree of influence of the humidity of the device installation environment on the ease of dew condensation adhesion varies depending on the internal structure (mechanical configuration) of the liquid ejection device 103.

[0094] [Nozzle Surface Ambient Temperature During Printing] The ambient temperature of the nozzle surface during printing is affected by the temperature of the recording medium P directly below the nozzle surface 1a and the indoor temperature (outdoor air exchange rate). When the temperature of the recording medium P directly below the nozzle surface 1a is high, the ambient temperature of the nozzle surface is higher compared to when it is low, and dew condensation is more likely to adhere to the nozzle surface 1a. The surface temperature of the recording medium P directly below the nozzle surface 1a varies depending on the storage state of the recording medium P immediately before printing. The storage state of the recording medium P is affected by the indoor temperature.

[0095] The back surface temperature of the recording medium P varies depending on the type of the recording medium P, the printing mode, and the indoor temperature. Depending on the printing mode, the printing speed, the set temperature by the drying unit 6, and the set temperature by the cooling unit 65 are different.

[0096] The influence of the nozzle surface ambient temperature on the ease of dew condensation attachment can be confirmed by conducting experiments. The back surface temperature of the recording medium P may be higher compared to the surface temperature due to the remaining influence of the heat by the drying unit 6. The temperature of the recording medium P is affected by the thickness of the recording medium P.

[0097] When the indoor temperature is high, dew condensation is more likely to adhere to the nozzle surface 1a compared to when the indoor temperature is low. The degree of influence of the indoor temperature on the ease of dew condensation varies depending on the internal structure of the liquid ejection device 103.

[0098] [Temperature of the nozzle surface 1a during printing] The temperature of the nozzle surface 1a during printing is affected by the temperature of the temperature adjustment liquid of the temperature adjustment mechanism 20 and the ambient temperature of the nozzle surface. When the temperature of the temperature adjustment liquid is low, the temperature of the nozzle surface 1a is lower compared to when the temperature of the temperature adjustment liquid is high, and dew condensation is more likely to adhere to the nozzle surface 1a. Since the purpose of the temperature adjustment mechanism 20 is to cool the liquid ejection head 10, if the temperature of the temperature adjustment liquid is increased, the function of cooling the liquid ejection head 10 will decline. The temperature of the temperature adjustment liquid is preferably set to the lowest temperature within the temperature range where dew condensation does not adhere to the nozzle surface 1a.

[0099] [Ambient humidity of the nozzle surface during capping] The ambient humidity of the nozzle surface during capping is affected by the structure of the cap 40. For example, when the gap between the nozzle surface 1a and the cap 40 is large, the ambient humidity of the nozzle surface is lower than that when the gap is small. During capping, the nozzle surface 1a is covered by the cap 40.

[0100] [Ambient Temperature of the Nozzle Surface During Capping] The ambient temperature of the nozzle surface during capping is affected by the room temperature. When the room temperature is high, the ambient temperature of the nozzle surface is higher than that when the room temperature is low.

[0101] [Temperature of the Nozzle Surface 1a During Capping] The temperature of the nozzle surface 1a during capping is affected by the temperature of the temperature adjustment liquid and the ambient temperature of the nozzle surface.

[0102] [Relationship between Room Temperature and Set Temperature in the Temperature Adjustment Mechanism 20] Next, the relationship between the room temperature and the set temperature in the temperature adjustment mechanism 20 will be described. FIG. 8 is a graph showing the relationship between the room temperature and the set temperature of the temperature adjustment mechanism 20. In FIG. 8, the horizontal axis represents the room temperature, and the vertical axis represents the set temperature in the temperature adjustment mechanism 20. The set temperature in the temperature adjustment mechanism 20 is proportional to the room temperature.

[0103] The set temperature in the first printing mode M1 and the second printing mode M2 is higher than the set temperature in the moisture retention mode M3. In other words, the set temperature in the moisture retention mode M3 is lower than the set temperature in the first printing mode M1 and the second printing mode M2. When the set temperature is lower than the set temperature in the moisture retention mode M3, dew condensation is likely to adhere to the nozzle surface 1a. In other words, the set temperature in the moisture retention mode M3 can be set to a temperature at which dew condensation is likely to adhere or higher. "Dew condensation is likely to adhere" may mean that droplets generated by dew condensation are likely to adhere. For example, the first printing mode M1 is a printing mode when printing on a recording medium P that is thin paper. The second printing mode M2 may be a printing mode when printing on a recording medium P that is thick paper. For example, the first printing mode M1 may be an operation mode when the conveyance speed of the recording medium P is slow, and the second printing mode M2 may be an operation mode when the conveyance speed of the recording medium P is fast. This is because after surface printing is performed and heating is performed by the drying unit 6, the recording medium P is cooled by the cooling unit 65. However, the thicker the paper or the higher the conveyance speed, the more likely it is that the cooling of the recording medium P by the cooling unit 65 will be insufficient. Therefore, especially during reverse side printing, since the temperature of the recording medium P is likely to rise, the ambient temperature is likely to rise, and dew condensation is likely to occur if the temperature of the liquid ejection head 10 is low. In the liquid ejection device 103, in order to prevent this, the set temperature by the temperature adjustment mechanism 20 is increased to raise the nozzle surface temperature.

[0104] Note that the set temperature in the moisture retention mode M3 may be a set temperature equal to or lower than the temperature at which dew condensation is likely to adhere to the nozzle surface 1a. The temperature control unit 543 of the temperature adjustment mechanism can control the set temperature based on the relationship between the indoor temperature shown in FIG. 8 and the set temperature in the temperature adjustment mechanism 20. By setting the set temperature in the first printing mode M1 and the second printing mode M2 to a temperature exceeding the temperature at which dew condensation is likely to adhere to the nozzle surface 1a, the temperature adjustment mechanism 20 can suppress the adhesion of dew condensation to the nozzle surface 1a.

[0105] [An example of the process in the control unit] FIG. 9 is a flowchart showing an example of the processing in the control unit 500. First, the control unit 500 determines whether the operation mode of the liquid ejection device 103 is the printing mode (step S11). The operation mode setting unit 535 of the control unit 500 can determine the current operation mode of the liquid ejection device 103. When the control unit 500 is in the printing mode (step S11; YES), it executes the process of step S12, and when it is in the moisturizing mode M3 (step S11; NO), it executes step S13. The control unit 500 may determine whether the cap 40 covers the nozzle surface 1a and also determine whether the moisturizing mode M3 is being executed. The printing mode may include the first printing mode M1 and the second printing mode M2 as described above.

[0106] In step S12, the control unit 500 calculates the set temperature in the temperature adjustment mechanism 20 using Equation A. Equation A may be, for example, an equation showing the relationship between the room temperature and the set temperature shown in FIG. 8. Equation A may be, for example, an equation related to the first printing mode M1 or an equation related to the second printing mode M2. The temperature adjustment mechanism temperature control unit 543 of the control unit 500 can derive the set temperature according to the type of the printing mode. In step S12, the control unit 500 can select Equation A for calculating the set temperature according to, for example, the paper thickness (thin paper or thick paper) of the recording medium P. In step S12, the control unit 500 can select Equation A for calculating the set temperature according to, for example, the conveyance speed of the recording medium P.

[0107] In step S13, the control unit 500 calculates the set temperature in the temperature adjustment mechanism 20 using Equation B. Equation B may be, for example, an equation showing the relationship between the room temperature and the set temperature shown in FIG. 8. Equation B may be, for example, an equation related to the moisturizing mode M3.

[0108] After executing the process of step S12 or step S13, the control unit 500 executes the process of step S14. In step S14, the control unit 500 applies the set temperature calculated in step S12 or step S13 to the temperature adjustment mechanism 20. The temperature adjustment mechanism temperature control unit 543 of the control unit 500 can control the temperature adjustment mechanism 20 so as to reach the set temperature. The set temperature may be a value related to the temperature of the nozzle surface 1a or the temperature of the temperature adjustment liquid. The set temperature may also be a temperature related to whether or not dew condensation adheres to the nozzle surface 1a. The control unit 500 can change the set temperature in the temperature adjustment mechanism 20 based on the indoor temperature and the operation mode.

[0109] [Operation and Effect of the Liquid Discharge Device 103 According to the Embodiment] The liquid discharge device 103 according to the embodiment includes a liquid discharge head 10 that has a nozzle surface 1a and discharges liquid, a temperature adjustment mechanism 20 that adjusts the temperature of the liquid discharge head 10, a cap 40 that covers the nozzle surface 1a, a temperature sensor 61 that detects the indoor temperature, and a control unit 500 that controls the temperature adjustment mechanism 20 based on the indoor temperature detected by the temperature sensor 61.

[0110] According to such a liquid discharge device 103, the temperature of the liquid discharge head 10 can be adjusted by controlling the temperature adjustment mechanism 20 based on the indoor temperature. Thereby, the temperature of the liquid discharge head 10 can be appropriately maintained, and dew condensation adhesion to the nozzle surface 1a can be suppressed. Further, according to the liquid discharge device 103, when the ink is not discharged, the drying of the ink in the nozzle N can be suppressed by covering the nozzle surface 1a with the cap 40. Thereby, an increase in the viscosity of the ink in the nozzle N can be suppressed. As a result, the reliability of the liquid discharge device 103 can be improved. As described above, it is possible to provide a liquid discharge device that can suppress the drying of the liquid in a state where the liquid is not discharged and suppress dew condensation adhesion to the nozzle surface in a state where the liquid is discharged.

[0111] In the liquid ejection device 103, when the ejection operation by the liquid ejection head 10 is not executed for a certain period (for example, about 1 hour), the control unit 500 stops the temperature adjustment by the temperature adjustment mechanism 20. Thereby, power saving in the liquid ejection device 103 can be achieved. Further, by stopping the temperature adjustment by the temperature adjustment mechanism 20, the ink temperature in the nozzle during standby can be made substantially equal to the nozzle surface ambient temperature, so that while preventing dew condensation on the nozzle surface, drying of the ink in the nozzle can be suppressed, and nozzle clogging can be suppressed. "Nozzle clogging" may mean that liquid cannot be ejected from the nozzle N. In the liquid ejection device 103, the temperature adjustment by the temperature adjustment mechanism 20 may be stopped by setting the operation mode to the moisture retention mode. In the moisture retention mode, the droplet ejection operation by the liquid ejection head 10 is not executed.

[0112] In the liquid ejection device 103, in a state where the cap 40 covers the nozzle surface 1a, the cap 40 is filled with a wetting liquid. Thereby, by evaporation of the wetting liquid inside the cap 40, improvement of the moisture retention performance can be achieved, and drying of the ink in the nozzle N can be suppressed.

[0113] The liquid ejection device 103 includes a plurality of liquid ejection heads 10, and the cap 40 covers the plurality of nozzle surfaces 1a of the plurality of liquid ejection heads 10. Thereby, one cap 40 can cover a plurality of nozzle surfaces 1a. As a result, in the liquid ejection device 103, the number of installed caps 40 can be reduced, and the device can be simplified.

[0114] The liquid ejection device 103 according to the embodiment includes a liquid ejection head 10 having a nozzle surface 1a for ejecting a liquid, a temperature adjustment mechanism 20 for adjusting the temperature of the liquid ejection head 10, a cap 40 for covering the nozzle surface 1a, a temperature sensor 61 for detecting the room temperature, and a control unit 500 for controlling the temperature adjustment mechanism 20 based on the temperature detected by the temperature sensor 61 and the operation mode. The operation mode includes a printing mode (liquid ejection mode) for ejecting a liquid from the liquid ejection head 10 and a moisture retention mode for covering the nozzle surface 1a with the cap 40 to retain moisture.

[0115] According to such a liquid ejection device 103, the temperature of the liquid ejection head 10 can be adjusted by controlling the temperature adjustment mechanism 20 based on the room temperature and the operation mode. Thereby, the temperature of the liquid ejection head 10 can be appropriately maintained, and dew condensation adhesion to the nozzle surface 1a can be suppressed. According to the liquid ejection device 103, the temperature control by the temperature adjustment mechanism 20 can be changed according to whether the operation mode is the printing mode or the moisture retention mode. Further, according to the liquid ejection device 103, when the ink is not ejected, the drying of the ink in the nozzle N can be suppressed by covering the nozzle surface 1a with the cap 40. As a result, an increase in the viscosity of the ink in the nozzle N can be suppressed. As a result, the reliability of the liquid ejection device 103 can be improved.

[0116] The liquid ejection device 103 includes a medium conveyance mechanism 50 that conveys the recording medium P, and the control unit 500 controls the temperature adjustment mechanism 20 based on the type of the recording medium P. Thereby, according to the recording medium P, the temperature adjustment by the temperature adjustment mechanism 20 can be changed. As a result, according to the liquid ejection device 103, the temperature of the liquid ejection head 10 can be appropriately maintained according to the type of the recording medium P, and dew condensation adhesion to the nozzle surface 1a can be suppressed.

[0117] In the liquid ejection device 103, when the thickness of the recording medium P is thick (for example, 250 μm), the control unit 500 controls the temperature adjustment mechanism 20 so that the temperature of the liquid ejection head 10 becomes higher compared to the case where the thickness of the recording medium P is thin. According to the liquid ejection device 103, the thicker the recording medium P, the higher the temperature of the nozzle surface 1a can be made, and condensation adhesion to the nozzle surface 1a can be suppressed. For example, when the thickness of the recording medium P is thick, the control unit 500 may set a higher temperature for the nozzle surface 1a of the liquid ejection head 10 on the downstream side that ejects ink onto the back surface of the recording medium P compared to the case where the thickness of the recording medium P is thin. Further, when the thickness of the recording medium P is equal to or greater than a reference value (for example, 250 μm), the control unit 500 may set the temperature of the liquid ejection head 10 higher according to the thickness, and when the thickness of the recording medium P is less than the reference value, the control unit 500 may set the temperature of the liquid ejection head 10 to a constant value. Note that "when the thickness of the recording medium P is thick" means "when the thickness of the recording medium is a second thickness that is thicker than the first thickness".

[0118] Also, the liquid ejection device 103 includes a humidity sensor 62 that detects the humidity in the vicinity of the liquid ejection head 10. When the humidity is high, the control unit 500 controls the temperature adjustment mechanism 20 so that the temperature of the liquid ejection head 10 becomes higher compared to the case where the humidity is low. According to the liquid ejection device 103, the higher the humidity, the higher the temperature of the nozzle surface 1a can be made, and condensation adhesion to the nozzle surface 1a can be suppressed. In this liquid ejection device 103, the temperature of the nozzle surface 1a can be set higher in accordance with an increase in the humidity of the nozzle surface atmosphere during printing. For example, when the humidity detected by the humidity sensor 62 is high, the control unit 500 may set a higher temperature for the nozzle surface 1a of the liquid ejection head 10 on the downstream side that ejects ink onto the back surface of the recording medium P compared to the case where the humidity is low. Note that "when the humidity is high" means "when the humidity is a second humidity that is higher than the first humidity".

[0119] Further, the liquid ejection device 103 includes a medium conveyance mechanism 50 that conveys the recording medium P. When the conveyance speed of the recording medium P is high (for example, 150 m / min), the control unit 500 controls the temperature adjustment mechanism 20 so that the temperature of the liquid ejection head 10 becomes higher than when the conveyance speed is low (for example, 100 m / min). According to the liquid ejection device 103, the higher the conveyance speed of the recording medium P, the higher the temperature of the nozzle surface 1a can be made, and dew condensation adhesion to the nozzle surface 1a can be suppressed. For example, when the conveyance speed is high, the control unit 500 may set a higher temperature for the nozzle surface 1a of the liquid ejection head 10 on the downstream side that ejects ink onto the back surface of the recording medium P as compared with when the speed is low. Note that "when the conveyance speed is high" means "when the conveyance speed is a second speed higher than the first speed".

[0120] Further, the liquid ejection device 103 includes a drying unit 6 that dries the recording medium P after the liquid has been ejected. When the set temperature by the drying unit 6 is high (for example, 120°C), the control unit 500 controls the temperature adjustment mechanism 20 so that the temperature of the liquid ejection head 10 becomes higher than when the set temperature by the drying unit 6 is low (for example, 60°C). According to the liquid ejection device 103, the higher the set temperature by the drying unit 6, the higher the temperature of the nozzle surface 1a can be made, and dew condensation adhesion to the nozzle surface 1a can be suppressed. For example, when the set temperature in the drying unit 6 is high, the control unit 500 may set a higher temperature for the nozzle surface 1a of the liquid ejection head 10 on the downstream side that ejects ink onto the back surface of the recording medium P as compared with when the set temperature in the drying unit 6 is low. Note that "when the set temperature by the drying unit is high" means "when the set temperature by the drying unit is a second temperature higher than the first temperature".

[0121] In addition, the liquid ejection device 103 includes a medium conveyance mechanism 50 that conveys a roll paper, which is a recording medium P, and the nozzle surface 1a extends in a direction intersecting the conveyance direction of the recording medium P. The direction intersecting the conveyance direction of the recording medium P is the width direction of the recording medium P. The liquid ejection device 103 may be a continuous accounting machine, and the liquid ejection head 10 may be a line head. Generally, a continuous accounting machine having a line head tends to have more dew condensation adhesion on the nozzle surface 1a. According to the liquid ejection device 103, dew condensation adhesion on the nozzle surface 1a can be suppressed.

[0122] The recording medium P has a first surface and a second surface facing each other in the thickness direction, and the liquid ejection head 10 ejects liquid onto the first surface and the second surface. The liquid ejection device 103 may be an image forming device capable of double-sided printing. Generally, an image forming device capable of double-sided printing tends to have more dew condensation adhesion on the nozzle surface 1a. According to the liquid ejection device 103, dew condensation adhesion on the nozzle surface 1a can be suppressed.

[0123] In the liquid ejection device 103, in a state where the liquid is being ejected by the liquid ejection head 10 and a state where the cap 40 covers the nozzle surface 1a, the control unit 500 controls the temperature adjustment mechanism 20 so that the liquid ejection heads 10 have different set temperatures. In the liquid ejection device 103, as described above, the temperature of the nozzle surface 1a can be changed depending on whether it is in the printing mode or the moisture retention mode. For example, in the moisture retention mode, power saving may be achieved by lowering the set temperature by the temperature adjustment mechanism 20. For example, in the printing mode, dew condensation adhesion on the nozzle surface 1a can be suppressed by raising the set temperature by the temperature adjustment mechanism 20.

[0124] In the liquid ejection device 103, the control unit 500 controls the temperature adjustment mechanism 20 so that the temperature of the nozzle surface 1a is a temperature at which dew condensation does not occur on the nozzle surface 1a. The temperature at which dew condensation does not occur on the nozzle surface 1a can be calculated, for example, by conducting experiments or simulations. The liquid ejection device 103 can suppress dew condensation adhesion on the nozzle surface 1a by setting the set temperature in the temperature adjustment mechanism 20 to a temperature at which dew condensation does not occur on the nozzle surface 1a.

[0125] Also, in the liquid ejection device 103, when the room temperature detected by the temperature sensor 61 is high, the control unit 500 controls the temperature adjustment mechanism 20 so that the temperature of the liquid ejection head 10 becomes higher than when the room temperature detected by the temperature sensor 61 is low. According to the liquid ejection device 103, the higher the room temperature, the higher the temperature of the nozzle surface 1a can be made, and dew condensation adhesion to the nozzle surface 1a can be suppressed. For example, when the room temperature detected by the temperature sensor 61 is high, the control unit 500 may set a higher temperature for the nozzle surface 1a of the liquid ejection head 10 on the downstream side where ink is ejected onto the back surface of the recording medium P, as compared with when the room temperature detected by the temperature sensor 61 is low. Note that "when the temperature detected by the temperature sensor is high" means "when the temperature detected by the temperature sensor is a second temperature higher than the first temperature".

[0126] In the liquid ejection device 103, the temperature adjustment mechanism 20 includes a circulation flow path for circulating a temperature adjustment fluid, and by circulating the temperature adjustment fluid, the temperature of the liquid ejection head 10 can be adjusted. According to the liquid ejection device 103, by circulating the temperature adjustment fluid, the temperature of the nozzle surface 1a can be stably maintained.

[0127] In the liquid ejection device 103, the liquid may be aqueous pigment ink. In an image forming device that ejects aqueous pigment ink, by adjusting the temperature of the nozzle surface 1a, dew condensation adhesion to the nozzle surface 1a can be suppressed. Generally, aqueous pigment ink easily generates water vapor and easily adheres dew condensation to the nozzle surface 1a, but according to the liquid ejection device 103, dew condensation adhesion to the nozzle surface 1a can be suppressed.

[0128] The purpose of adjusting the temperature of the liquid ejection head 10 by the temperature adjustment mechanism 20 is to suppress a decrease in the ink viscosity in the liquid chamber due to the temperature rise during head driving. For example, when the ink is cooled by the temperature adjustment mechanism 20 to adjust the ink viscosity, the temperature of the nozzle surface 1a may decrease, and as a result, dew condensation may occur on the nozzle surface 1a. In the liquid ejection device 103 according to the present embodiment, according to the liquid ejection device 103, based on the room temperature, by controlling the temperature adjustment mechanism 20, the temperature of the liquid ejection head 10 can be adjusted. Thereby, the temperature of the liquid ejection head 10 can be appropriately maintained, and dew condensation adhesion to the nozzle surface 1a can be suppressed. For example, in the liquid ejection head 10, a heat insulating material may be provided between the liquid chamber and the nozzle surface 1a, but in the liquid ejection device 103 according to the present embodiment, by adjusting the temperature of the liquid ejection head 10, dew condensation on the nozzle surface 1a is suppressed. Therefore, dew condensation adhesion to the nozzle surface 1a can be suppressed without providing a heat insulating material between the liquid chamber and the nozzle surface 1a.

[0129] [Liquid ejection system 100] Next, the liquid ejection system 100 will be described. FIG. 10 is a schematic diagram showing an example of a liquid ejection system 100 according to an embodiment of the present invention. The liquid ejection system 100 shown in FIGS. 10 to 12 includes a client PC (Personal Computer) 101, a DFE (Digital Front End) 102, a liquid ejection device 103, and a management server 104. These are connected to be communicable with each other via the Internet or the like. The liquid ejection system 100 may be an image forming system. The liquid ejection system (image forming system) 100 may include a liquid ejection device (image forming device) 103.

[0130] The client PC 101 creates a print job that the user wants to print and transmits the print job to the DFE 102 or the management server 104. It is provided with a display unit that is a liquid crystal display and input devices such as a mouse and a keyboard.

[0131] DFE102 receives a print job from the client PC 101 or the management server 104, creates rendering data by a RIP (Raster Image Processor) engine based on the received print job, and transmits the rendering data to the liquid ejection device 103. Here, DFE102 may be an information processing device.

[0132] Based on the rendering data received from DFE102, the liquid ejection device 103 forms an image on the recording medium P. The management server 104 manages the print jobs received from the client PC 101. Also, the management server 104 transmits a print job to DFE102 in response to a request from DFE102. Note that a plurality of liquid ejection devices 103 and a plurality of client PCs 101 may be communicably connected to the liquid ejection system 100.

[0133] [Hardware of DFE102] Next, an example of the hardware configuration of DFE102 will be described. FIG. 11 is a block diagram showing the hardware configuration of DFE102 according to an embodiment of the present invention. DFE102 includes a CPU (Central Processing Unit) 201, a ROM (Read Only Memory) 202, a RAM (Random Access Memory) 203, an HDD (Hard Disk Drive) / SSD (Solid State Drive) 204, and an I / F (Interface) 205.

[0134] Among these, the CPU 201 uses the RAM 203 as a work area and controls the operation of the entire DFE102 by executing the programs stored in the ROM 202. The HDD / SDD 204 is used as a storage unit and stores preset setting values. The information stored in the HDD / SSD 204 may be used by the CPU 201 when reading and executing programs. The I / F 205 is an interface that enables communication between DFE102 and the client PC 101, the liquid ejection device 103, and the management server 104.

[0135] [Hardware of the Liquid Discharge Device 103] Next, the hardware configuration of the liquid discharge device 103 will be described. FIG. 12 is a block diagram showing the hardware configuration of the liquid discharge device 103 according to an embodiment of the present invention. The liquid discharge device 103 includes a CPU 301, a ROM 302, a RAM 303, an HDD / SSD 304, an I / F 305, an image forming unit 306, and a reading unit 307. The image forming unit 306 may be a liquid discharge unit.

[0136] Among these, the CPU 301 uses the RAM 303 as a work area and executes the programs stored in the ROM 302 to control the operation of the entire liquid discharge device 103. The HDD / SDD 304 is used as a storage unit and stores preset setting values. The information stored in the HDD / SSD 304 may be used by the CPU 301 when reading and executing programs.

[0137] The I / F 305 is an interface that enables the liquid discharge device 103 to communicate with the DEF 102, the client PC 101, and the management server 104. The image forming unit 306 is a printing engine that forms a printed image on a printing paper (recording medium P). The reading unit 307 is a reading device that reads the printed image formed on the printing paper.

[0138] [Liquid Discharge System 100 According to the Embodiment] The liquid discharge system 100 according to the embodiment includes a liquid discharge head 10 having a nozzle surface 1a for discharging liquid, a temperature adjustment mechanism 20 for adjusting the temperature of the liquid discharge head 10, a cap 40 covering the nozzle surface 1a, a temperature sensor 61 for detecting the indoor temperature, and a control unit 500 for controlling the temperature adjustment mechanism 20 based on the indoor temperature detected by the temperature sensor 61 and the operation mode. The liquid discharge system 100 may include the control unit 500 outside the liquid discharge device 103.

[0139] The liquid ejection system 100 may include a liquid ejection head 10 that has a nozzle surface 1a and ejects liquid, a temperature adjustment mechanism 20 that adjusts the temperature of the liquid ejection head 10, a cap 40 that covers the nozzle surface 1a, a temperature sensor 61 that detects the indoor temperature, and a control unit 500 that controls the temperature adjustment mechanism 20 based on the indoor temperature detected by the temperature sensor 61 and the operation mode. The operation mode includes a liquid ejection mode in which liquid is ejected from the liquid ejection head 10 and a moisturizing mode in which the nozzle surface 1a is covered with the cap 40 to maintain moisture.

[0140] [Liquid ejection method] The liquid ejection method according to the embodiment includes a liquid ejection step of ejecting liquid from a liquid ejection head 10 having a nozzle surface 1a, a step of covering the nozzle surface 1a with a cap 40 in a state where no liquid is ejected from the liquid ejection head 10, a temperature detection step of detecting the indoor temperature, and a temperature adjustment step of adjusting the temperature of the liquid ejection head 10 based on the indoor temperature detected in the temperature detection step.

[0141] The liquid ejection method may include a liquid ejection step of ejecting liquid from a liquid ejection head 10 having a nozzle surface 1a, a step of covering the nozzle surface 1a with a cap 40 in a state where no liquid is ejected from the liquid ejection head 10, a temperature detection step of detecting the indoor temperature, and a temperature adjustment step of adjusting the temperature of the liquid ejection head 10 based on the indoor temperature detected in the temperature detection step and the operation mode. The operation mode includes a liquid ejection mode in which liquid is ejected from the liquid ejection head 10 and a moisturizing mode in which the nozzle surface 1a is covered with the cap 40 to maintain moisture.

[0142] [Program] The program according to the embodiment is a program that causes a computer to execute control processing for executing a liquid discharge step of discharging liquid from a liquid discharge head 10 having a nozzle surface 1a. In a state where no liquid is discharged from the liquid discharge head 10, the program causes the computer to execute a process of covering the nozzle surface 1a with a cap 40, a process of detecting the indoor temperature, and a process of adjusting the temperature of the liquid discharge head 10 based on the indoor temperature detected in the temperature detection step.

[0143] The program is a program that causes a computer to execute control processing for executing a liquid discharge step of discharging liquid from a liquid discharge head 10 having a nozzle surface 1a. In a state where no liquid is discharged from the liquid discharge head 10, the program may cause the computer to execute a process of covering the nozzle surface 1a with a cap 40, a process of detecting the indoor temperature, and a process of adjusting the temperature of the liquid discharge head 10 based on the indoor temperature detected in the temperature detection step and the operation mode. The operation mode includes a liquid discharge mode in which liquid is discharged from the liquid discharge head 10 and a moisturizing mode in which the nozzle surface 1a is covered with a cap 40 to maintain moisture.

[0144] [Liquid discharge head 10 according to the first modification example] FIG. 13 is a bottom view showing the nozzle plate 1 of the liquid discharge head 10 according to the first modification example. A plurality of nozzle rows are formed on the nozzle surface 1a of the liquid discharge head 10 according to the first modification example. The nozzle row has a plurality of nozzles N arranged in the Y-axis direction. The plurality of nozzle rows are arranged apart from each other in the X-axis direction. The liquid discharge head 10 may have the nozzle plate 1 shown in FIG. 13.

[0145] [Liquid discharge head 10 according to the second modification example] FIG. 14 is a bottom view showing the nozzle plate 1 of the liquid discharge head 10 according to the second modification example. For example, four nozzle rows are formed on the nozzle plate 1 of the liquid discharge head according to the second modification example. In a plurality of nozzle rows adjacent to each other in the X-axis direction, the nozzles N may be arranged shifted in the Y-axis direction.

[0146] [Liquid ejection head 10 according to the third modification example] FIG. 15 is a bottom view showing the nozzle plate 1 of the liquid ejection head 10 according to the third modification example. The liquid ejection head 10 according to the third modification example includes a plurality of nozzle plates 1. The plurality of nozzle plates 1 are arranged in the Y-axis direction.

[0147] [Liquid ejection head 10 according to the fourth modification example] FIG. 16 is a bottom view showing the nozzle plate 1 of the liquid ejection head 10 according to the fourth modification example. The liquid ejection head 10 according to the fourth modification example includes a pair of nozzle plates 1 adjacent to each other in the X-axis direction. The plurality of nozzle plates 1 may be arranged apart from each other in the Y-axis direction. The plurality of nozzle plates 1 may be arranged shifted in the Y-axis direction. The plurality of nozzle plates 1 may be arranged in a staggered pattern. A pair of nozzle plates 1 adjacent to each other in the X-axis direction may be arranged shifted in the Y-axis direction.

[0148] Note that the above-described embodiments are presented as an example and are not intended to limit the scope of the present invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. Also, the embodiments and modifications of the embodiments are included in the scope and gist of the invention and are included in the invention described in the claims and the equivalent scope thereof.

[0149] In this specification, image formation, printing, printing, or recording are all synonymous.

[0150] [Processing circuit] Each function of the embodiment described above can be realized by one or more processing circuits. Here, the "processing circuit" in this specification refers to a processor programmed to execute each function by software, such as a processor implemented by an electronic circuit, an ASIC (Application Specific Integrated Circuit) designed to execute each function described above, a DSP (digital signal processor), an FPGA (field programmable gate array), and devices such as conventional circuit modules.

[0151] In the above embodiment, the liquid ejection device 103 including the liquid ejection head 10 which is a line head has been described. However, the liquid ejection head 10 is not limited to a line head. The liquid ejection device 103 may include a carriage on which the liquid ejection head 10 is mounted. The liquid ejection device 103 may include a serial type liquid ejection head 10.

[0152] The recording medium P may be plain paper, glossy paper, film, or the like.

[0153] The liquid ejected from the liquid ejection head 10 is not limited to ink. The liquid may be a solvent such as water or an organic solvent. The liquid may be a liquid containing a coloring agent such as a dye or a pigment. The liquid may be a liquid containing a functional group imparting material such as a polymerizable compound, a resin, or a surfactant. The liquid may be a liquid containing a biocompatible material such as DNA, an amino acid, a protein, or calcium. The liquid may be a liquid containing an edible material such as a natural pigment. The liquid may be a suspension, an emulsion, or the like.

[0154] The liquid may be, for example, ink for inkjet or a surface treatment liquid. The liquid may be a forming liquid for forming components of an electronic element or a light emitting element. The liquid may be a liquid for forming an electronic circuit resist pattern. The liquid may be a material liquid for three-dimensional modeling.

[0155] One aspect of the present invention may be as follows.

[0156] <1> A liquid ejection head having a nozzle surface for ejecting a liquid, a temperature adjustment mechanism for adjusting the temperature of the liquid ejection head, a temperature sensor for detecting the room temperature or the temperature around the nozzle surface, and a control unit for controlling the temperature adjustment mechanism based on the temperature detected by the temperature sensor. A liquid ejection apparatus comprising the same. <2> The liquid ejection apparatus according to <1> above, wherein the control unit stops the temperature adjustment by the temperature adjustment mechanism when the ejection operation by the liquid ejection head is not executed for a certain period of time. <3> Comprising a cap covering the nozzle surface, The liquid ejection apparatus according to <1> or <2> above, wherein a wetting liquid is filled in the cap in a state where the cap covers the nozzle surface. <4> Comprising a plurality of the liquid ejection heads, Comprising a cap covering the nozzle surface, The liquid ejection apparatus according to any one of <1> to <3> above, wherein the cap covers the plurality of nozzle surfaces of the plurality of liquid ejection heads. <5> A liquid ejection head having a nozzle surface for ejecting a liquid, a temperature adjustment mechanism for adjusting the temperature of the liquid ejection head, a cap covering the nozzle surface, a temperature sensor for detecting the room temperature or the temperature around the nozzle surface, and a control unit for controlling the temperature adjustment mechanism based on the temperature detected by the temperature sensor and the operation mode. The liquid ejection apparatus comprising the same, wherein the operation mode includes a liquid ejection mode for ejecting a liquid from the liquid ejection head, and a moisture retention mode for covering the nozzle surface with the cap to retain moisture. <6> Comprising a medium conveyance mechanism for conveying a recording medium, The control unit The liquid ejection device according to claim 5, wherein the control unit controls the temperature adjustment mechanism based on the type of the recording medium.<5> <7> The control unit The liquid ejection device according to any one of <5> or <6>, wherein when the thickness of the recording medium is a second thickness greater than a first thickness, the control unit controls the temperature adjustment mechanism so that the temperature of the liquid ejection head is higher than when the thickness of the recording medium is the first thickness.<5> <8> The liquid ejection device includes a humidity sensor that detects the humidity in the vicinity of the liquid ejection head, The control unit The liquid ejection device according to any one of <5> to <7>, wherein when the humidity is a second humidity higher than a first humidity, the control unit controls the temperature adjustment mechanism so that the temperature of the liquid ejection head is higher than when the humidity is the first humidity.<5> <9> The liquid ejection device includes a medium conveyance mechanism that conveys the recording medium, The control unit The liquid ejection device according to any one of <5> to <8>, wherein when the conveyance speed of the recording medium is a second speed higher than a first speed, the control unit controls the temperature adjustment mechanism so that the temperature of the liquid ejection head is higher than when the conveyance speed is the second speed.<5> <10> The liquid ejection device includes a drying unit that dries the recording medium after the liquid is ejected, The control unit The liquid ejection device according to any one of <5> to <9>, wherein when the set temperature by the drying unit is a second temperature higher than a first temperature, the control unit controls the temperature adjustment mechanism so that the temperature of the liquid ejection head is higher than when the set temperature by the drying unit is the first temperature.<5> <11> The liquid ejection device includes a medium conveyance mechanism that conveys a roll paper as the recording medium, The liquid ejection device according to any one of <5> to <10>, wherein the longitudinal direction of the nozzle surface extends in a direction intersecting the conveyance direction of the recording medium.<5> <12> The recording medium has a first surface and a second surface facing each other in the thickness direction, The liquid ejection head is the liquid ejection device according to any one of <5> to <11> above that ejects liquid onto the first surface and the second surface. <13> comprises a cap that covers the nozzle surface, In a state where the liquid ejection head is ejecting liquid and a state where the cap covers the nozzle surface, the control unit controls the temperature adjustment mechanism so that the liquid ejection heads have different set temperatures. The liquid ejection device according to any one of <1> to <12> above. <14> The control unit, When the temperature detected by the temperature sensor is high, compared with the case where the temperature detected by the temperature sensor is low, the control unit controls the temperature adjustment mechanism so that the temperature of the liquid ejection head becomes a high temperature. The liquid ejection device according to any one of <1> to <13> above. <15> The temperature adjustment mechanism, includes a circulation flow path for circulating a temperature adjustment fluid, and adjusts the temperature of the liquid ejection head by circulating the temperature adjustment fluid. The liquid ejection device according to any one of <1> to <14> above. <16> The liquid is aqueous pigment ink. The liquid ejection device according to any one of <1> to <15> above. <17> a liquid ejection head having a nozzle surface and ejecting liquid, a temperature adjustment mechanism for adjusting the temperature of the liquid ejection head, a cap that covers the nozzle surface, a temperature sensor that detects the room temperature or the temperature around the nozzle surface, and a control unit that controls the temperature adjustment mechanism based on the temperature detected by the temperature sensor. An image forming apparatus comprising: <18> a liquid ejection head having a nozzle surface and ejecting liquid, A temperature adjustment mechanism for adjusting the temperature of the liquid ejection head; A cap that covers the nozzle surface; A temperature sensor that detects the indoor temperature or the temperature around the nozzle surface; A control unit that controls the temperature adjustment mechanism based on the temperature detected by the temperature sensor and the operation mode; and The operation mode is A liquid ejection mode in which liquid is ejected from the liquid ejection head; A moisturizing mode in which the nozzle surface is covered with the cap to maintain moisture, and an image forming apparatus including the same.

Explanation of Signs

[0157] 103 Liquid ejection device (image forming apparatus) 1a Nozzle surface 3 Head unit 10 Liquid ejection head 20 Temperature adjustment mechanism 40 Cap 50 Medium conveyance mechanism 61 Temperature sensor 62 Humidity sensor 100 Liquid ejection system 500 Control unit P Recording medium

Prior Art Documents

Patent Documents

[0158]

Patent Document 1

Claims

1. a liquid ejection head having a nozzle surface for ejecting liquid; a temperature adjustment mechanism for adjusting the temperature of the liquid ejection head; a temperature sensor for detecting a room temperature or a temperature around the nozzle surface; A control unit that controls the temperature adjustment mechanism based on the temperature detected by the temperature sensor.

2. The liquid ejection device according to claim 1 , wherein the control unit stops the temperature adjustment by the temperature adjustment mechanism when the ejection operation by the liquid ejection head is not performed for a certain period of time.

3. a cap for covering the nozzle surface, The liquid ejection device according to claim 1 , wherein the cap is filled with dampening liquid when the cap covers the nozzle surface.

4. A liquid ejection head according to the present invention includes: a cap for covering the nozzle surface, The liquid ejection apparatus according to claim 1 , wherein the cap covers the nozzle faces of the liquid ejection heads.

5. a liquid ejection head having a nozzle surface for ejecting liquid; a temperature adjustment mechanism for adjusting the temperature of the liquid ejection head; a cap for covering the nozzle surface; a temperature sensor for detecting a room temperature or a temperature around the nozzle surface; A control unit that controls the temperature adjustment mechanism based on the temperature detected by the temperature sensor and an operation mode, The operation mode is a liquid ejection mode in which liquid is ejected from the liquid ejection head; a moisturizing mode in which the nozzle surface is covered with the cap to moisturize the nozzle surface.

6. A medium transport mechanism for transporting a recording medium is provided, The control unit is The liquid ejection apparatus according to claim 5 , wherein the temperature adjustment mechanism is controlled based on the type of the recording medium.

7. The control unit is A liquid ejection device as described in claim 6, wherein the temperature adjustment mechanism is controlled so that when the thickness of the recording medium is a second thickness that is thicker than the first thickness, the temperature of the liquid ejection head is higher than when the thickness of the recording medium is the first thickness.

8. a humidity sensor for detecting humidity in the vicinity of the liquid ejection head; The control unit is A liquid ejection device as described in claim 5, wherein the temperature adjustment mechanism is controlled so that when the humidity is a second humidity higher than the first humidity, the temperature of the liquid ejection head is higher than when the humidity is the first humidity.

9. A medium transport mechanism for transporting a recording medium is provided, The control unit is A liquid ejection device as described in claim 5, wherein the temperature adjustment mechanism is controlled so that when the transport speed of the recording medium is a second speed faster than a first speed, the temperature of the liquid ejection head is higher than when the transport speed is the second speed.

10. a drying unit that dries the recording medium after the liquid is ejected; The control unit is A liquid ejection device as described in claim 5, wherein the temperature adjustment mechanism is controlled so that when the set temperature by the drying unit is a second temperature higher than the first temperature, the temperature of the liquid ejection head is higher than when the set temperature by the drying unit is the first temperature.

11. A medium transport mechanism is provided for transporting roll paper, which is a recording medium; The liquid ejection device according to claim 5 , wherein a longitudinal direction of the nozzle surface extends in a direction intersecting a transport direction of the recording medium.

12. the recording medium has a first surface and a second surface opposed to each other in a thickness direction; The liquid ejection apparatus according to claim 5 , wherein the liquid ejection head ejects liquid onto the first surface and the second surface.

13. a cap for covering the nozzle surface, A liquid ejection device as described in claim 1 or 5, wherein the control unit controls the temperature adjustment mechanism so that the liquid ejection head has different set temperatures when the liquid ejection head is ejecting liquid and when the cap is covering the nozzle surface.

14. The control unit is A liquid ejection device as described in claim 1 or 5, wherein when the temperature detected by the temperature sensor is a second temperature higher than a first temperature, the temperature adjustment mechanism is controlled so that the temperature of the liquid ejection head is higher than when the temperature detected by the temperature sensor is the first temperature.

15. The temperature adjustment mechanism includes:

6. The liquid ejection apparatus according to claim 1, further comprising a circulation flow path for circulating a temperature adjusting fluid, and the temperature of the liquid ejection head is adjusted by circulating the temperature adjusting fluid.

16. 6. The liquid ejection apparatus according to claim 1, wherein the liquid is a water-based pigment ink.

17. a liquid ejection head having a nozzle surface for ejecting liquid; a temperature adjustment mechanism for adjusting the temperature of the liquid ejection head; a temperature sensor for detecting a room temperature or a temperature around the nozzle surface; a control unit that controls the temperature adjustment mechanism based on the temperature detected by the temperature sensor.

18. a liquid ejection head having a nozzle surface for ejecting liquid; a temperature adjustment mechanism for adjusting the temperature of the liquid ejection head; a cap for covering the nozzle surface; a temperature sensor for detecting a room temperature or a temperature around the nozzle surface; A control unit that controls the temperature adjustment mechanism based on the temperature detected by the temperature sensor and an operation mode, The operation mode is a liquid ejection mode in which liquid is ejected from the liquid ejection head; a moisturizing mode in which the nozzle surface is covered with the cap to moisten the nozzle surface.

Images