Ink jet recording device

Abstract

To shorten the first print time while suppressing power consumption of a nozzle unit and a cooling device.SOLUTION: A nozzle unit 30 includes a first heater 36, a first temperature sensor 37, and a drive circuit 300. A second heater 52 heats the nozzle unit 30 from the outside. A second temperature sensor 53 detects the external temperature of the nozzle unit 30. A control unit 8d adjusts the power supplied to the first heater 36 through first temperature feedback control. The control unit 8d activates a cooling device 51 when the first detected temperature exceeds an allowable temperature under the condition that the first temperature feedback control is being executed. The control unit 8d stops power supply to the first heater 36 and the drive circuit 300 when a resting condition is satisfied. The control unit 8d adjusts the power supplied to the second heater 52 through second temperature feedback control during the resting state.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an inkjet recording apparatus capable of heating and cooling a nozzle unit.

Background Art

[0002] An inkjet recording apparatus includes a nozzle unit including a plurality of piezoelectric elements and a plurality of nozzles. Each of the piezoelectric elements pressurizes ink with energy corresponding to a drive signal by being supplied with the drive signal. By pressurizing the ink according to the drive signal by each of the piezoelectric elements, each of the nozzles discharges the ink.

[0003] It is known that the nozzle unit has a heater and a temperature sensor. (See, for example, Patent Document 1). The power supplied to the heater is adjusted by feedback control based on the detected temperature of the temperature sensor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, the nozzle unit includes a drive circuit that supplies a drive signal to each of the piezoelectric elements. When the drive circuit generates heat, the temperature of the nozzle unit rises.

[0006] When the inkjet recording apparatus is performing continuous print processing, it is necessary to suppress excessive temperature rise of the nozzle unit due to heat generation of the drive circuit. Therefore, the inkjet recording apparatus may include a cooling device.

[0007] On the one hand, it is required to be able to shorten the first print time while suppressing the power consumption of the nozzle unit and the cooling device.

[0008] An object of the present invention is to provide an inkjet recording apparatus capable of shortening the first print time while suppressing the power consumption of a nozzle unit and a cooling device.

Means for Solving the Problems

[0009] An inkjet recording apparatus according to one aspect of the present invention includes a nozzle unit having a plurality of nozzles, a plurality of piezoelectric elements, a first heater, and a first temperature sensor, a second heater, a cooling device, a second temperature sensor, and a control unit. The plurality of piezoelectric elements correspond to the plurality of nozzles. The drive circuit can supply drive signals to the plurality of piezoelectric elements. The nozzle unit forms an image on a sheet with ink ejected from the plurality of nozzles by supplying the drive signals to the plurality of piezoelectric elements. The second heater heats the nozzle unit from the outside. The cooling device cools the nozzle unit with a refrigerant liquid. The second temperature sensor detects the temperature outside the nozzle unit. The control unit controls the first heater, the drive circuit, the second heater, and the cooling device. The control unit adjusts the power supplied to the first heater by first temperature feedback control based on a first detected temperature detected by the first temperature sensor and a first target temperature. Further, the control unit operates the cooling device when the first detected temperature exceeds an allowable temperature in a situation where the first temperature feedback control is being executed. Further, the control unit stops the power supply to the first heater and the drive circuit when a pause condition including not receiving an image formation request is satisfied in a situation where the first temperature feedback control is being executed. Further, the control unit adjusts the power supplied to the second heater by second temperature feedback control based on a second detected temperature detected by the second temperature sensor and a second target temperature in a pause state where the power supply to the first heater and the drive circuit is stopped. Further, when the control unit receives the image formation request in the pause state, the control unit starts adjusting the power supplied to the first heater by the first temperature feedback control.

Effect of the Invention

[0010] According to the present invention, it is possible to provide an inkjet recording apparatus that can shorten the first print time while suppressing the power consumption of the nozzle unit and the cooling device.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following embodiments are examples of embodying the present invention and do not limit the technical scope of the present invention.

[0013] [Configuration of Inkjet Recording Apparatus 10] The inkjet recording apparatus 10 according to the embodiment is a printer capable of performing printing processing by an inkjet method.

[0014] The printing process is a process of forming an image on the sheet 9. The sheet 9 is a sheet-like image forming medium such as paper or a resin film.

[0015] Note that the inkjet recording apparatus 10 may be a facsimile apparatus, a copying machine, or a multifunction machine that can execute the printing process by an inkjet method.

[0016] As shown in FIG. 1, the inkjet recording apparatus 10 includes a sheet storage unit 1, a sheet conveyance device 2, a printing unit 3, a plurality of ink supply units 4, a control device 8, and the like.

[0017] The sheet storage unit 1, the sheet conveyance device 2, the printing unit 3, the plurality of ink supply units 4, and the control device 8 are arranged within the main housing 11. Further, the image forming apparatus 10 includes an operation device 801 and a display device 802.

[0018] The sheet conveyance device 2 feeds out the sheets 9 stored in the sheet storage unit 1 one by one to the conveyance path 20, and further conveys the sheets 9 along the conveyance path 20.

[0019] The sheet conveyance device 2 includes a feeding mechanism 21, a plurality of sets of conveyance roller pairs 22, a belt conveyance mechanism 23, a discharge roller pair 24, and the like. The feeding mechanism 21 feeds out the sheets 9 from the sheet storage unit 1 to the conveyance path 20. The plurality of sets of conveyance roller pairs 22 convey the sheets 9 along the conveyance path 20 and further convey the sheets 9 to the belt conveyance mechanism 23.

[0020] The belt conveyance mechanism 23 is arranged below the printing unit 3. The belt conveyance mechanism 23 includes a conveyance belt 231 and a plurality of tension rollers 232.

[0021] The plurality of tension rollers 232 rotatably support the conveyance belt 231. A motor (not shown) rotates one of the plurality of tension rollers 232 to rotate the conveyance belt 231. The conveyance belt 231 rotates to convey the sheet 9 in the conveyance direction D0 on its upper surface.

[0022] The direction orthogonal to the conveyance direction D0 is the main scanning direction D1, and the direction along the conveyance direction D0 is the sub-scanning direction D2 (see FIG. 1).

[0023] The printing unit 3 forms an image on the sheet 9 by discharging inks of a plurality of colors toward the sheet 9 conveyed by the belt conveyance mechanism 23.

[0024] The discharge roller pair 24 is disposed on the downstream side in the conveyance direction D0 with respect to the belt conveyance mechanism 23. The discharge roller pair 24 discharges the sheet 9 on which the image is formed to the outside of the main housing 11. For example, the discharge roller pair 24 sends out the sheet 9 from the main housing 11 to a discharge tray or a subsequent device disposed adjacent to the inkjet recording apparatus 10.

[0025] The plurality of ink supply units 4 supply inks of predetermined colors to the printing unit 3 respectively. For example, the colors of the inks are black, cyan, magenta, and yellow. In this case, the inkjet recording apparatus 10 includes four ink supply units 4.

[0026] [Printing unit 3] The printing unit 3 forms an image on the sheet 9 by discharging ink onto the sheet 9 conveyed by the belt conveyance mechanism 23. The printing unit 3 includes a plurality of nozzle units 30 corresponding to a plurality of ink colors.

[0027] The printing unit 3 includes a plurality of nozzle units 30 corresponding to a plurality of ink colors. The plurality of ink supply units 4 supply ink to the plurality of nozzle units 30.

[0028] In the present embodiment, the printing unit 3 includes four nozzle units 30 corresponding to black, cyan, magenta, and yellow inks.

[0029] Each of the nozzle units 30 has an ink ejection portion 31. The ink ejection portion 31 is disposed to face the upper surface of the conveyance belt 231.

[0030] The ink ejection unit 31 includes a plurality of nozzles 32 (see FIG. 2). By ejecting ink from each of the plurality of nozzles 32 onto the sheet 9, an image is formed on the sheet 9.

[0031] Furthermore, the ink ejection unit 31 includes a plurality of piezoelectric elements 33, a plurality of pressure chambers 35, and a plurality of diaphragms 34. The plurality of piezoelectric elements 33, the plurality of pressure chambers 35, and the plurality of diaphragms 34 are provided corresponding to the plurality of nozzles 32, respectively.

[0032] The plurality of pressure chambers 35 communicate with the plurality of nozzles 32, respectively. The plurality of pressure chambers 35 form passages for the ink supplied to the plurality of nozzles 32, respectively. The ink in the plurality of pressure chambers 35 is supplied to the plurality of nozzles 32, respectively.

[0033] The plurality of diaphragms 34 each form a part of the partition walls of the plurality of pressure chambers 35. Each of the piezoelectric elements 33 pressurizes the ink in the pressure chamber 35 via each of the diaphragms 34 when a drive signal is supplied.

[0034] The drive signal is a signal whose waveform is adjusted according to the size of the ink droplets to be ejected. The drive signal is supplied from the control device 8 to each of the piezoelectric elements 33.

[0035] That is, each of the piezoelectric elements 33 pressurizes the ink supplied to the plurality of nozzles 32, respectively, when the drive signal is supplied from the control device 8.

[0036] The piezoelectric element 33 to which the drive signal is supplied vibrates with the energy by which ink is ejected from the corresponding nozzle 32. That is, each of the piezoelectric elements 33 pressurizes the ink in the pressure chamber 35 to such an extent that the ink is ejected from the nozzle 32 when the drive signal is supplied.

[0037] The ink pressurized by the piezoelectric element 33 to which the drive signal is supplied flows from the pressure chamber 35 into the corresponding nozzle 32 and is further ejected from the nozzle 32.

[0038] Each nozzle unit 30 further includes a unit heater 36 and a unit temperature sensor 37 (see FIG. 2). The unit heater 36 and the unit temperature sensor 37 are disposed in the ink ejection portion 31 of each nozzle unit 30.

[0039] That is, the inkjet recording apparatus 10 includes a plurality of unit heaters 36 and a plurality of unit temperature sensors 37 corresponding to the plurality of nozzle units 30.

[0040] The unit heater 36 heats the ink ejection portion 31. The unit temperature sensor 37 detects the temperature of the ink ejection portion 31. That is, the unit temperature sensor 37 detects the temperature of the nozzle unit 30 on the nozzle unit 30. For example, the unit temperature sensor 37 is a thermistor.

[0041] When the temperature of the ink decreases, the viscosity of the ink increases. When the viscosity of the ink supplied to each nozzle 32 is high, the ejection performance of the ink from each nozzle 32 when each piezoelectric element 33 operates deteriorates.

[0042] The unit heater 36 maintains the viscosity of the ink supplied to each nozzle 32 in an appropriate state by heating the ink in the ink ejection portion 31.

[0043] Before the printing process is started, the unit heater 36 heats the ink in the ink ejection portion 31, thereby shortening the first print time. The first print time is the time from when the inkjet recording apparatus 10 receives a print request until the printing process is started.

[0044] The power supplied to the unit heater 36 is adjusted by feedback control based on the detected temperature of the unit temperature sensor 37.

[0045] The operation device 801 accepts human operations. For example, the operation device 801 includes one or both of a touch panel and one or more operation buttons. The display device 802 can display various types of information. For example, the display device 802 is a panel display device such as a liquid crystal panel unit.

[0046] [Control device 8] The control device 8 executes various data processes and controls the devices provided in the inkjet recording device 10.

[0047] As shown in FIG. 3, the control device 8 includes a CPU (Central Processing Unit) 81 and peripheral devices such as a RAM (Random Access Memory) 82, a secondary storage device 83, and a signal interface 84. Further, the control device 8 includes a communication device 85 and a heater power supply circuit 86.

[0048] The CPU 81 is a processor that executes various data processes and controls by executing a computer program. The CPU 81 is an example of a processor that controls a plurality of piezoelectric elements 33 and other devices.

[0049] The RAM 82 is a volatile storage device readable by a computer. The RAM 82 primary stores the computer program executed by the CPU 81 and the data output and referenced during the process of the CPU 81 executing various processes.

[0050] The secondary storage device 83 is a non-volatile storage device readable by a computer. The secondary storage device 83 can store and update the computer program and various data. For example, one or both of a flash memory and a hard disk drive are adopted as the secondary storage device 83.

[0051] The signal interface 84 converts the signals output by various sensors into digital data and transmits the converted digital data to the CPU 81. Further, the signal interface 84 converts the control commands output by the CPU 81 into control signals and transmits the control signals to the devices to be controlled.

[0052] The communication device 85 can communicate with a host device (not shown) and other devices. The host device is an information processing device such as a personal computer or a smartphone operated by a user.

[0053] For example, the CPU 81 receives a print job from the host device through the communication device 85. The printing unit 3 forms an image specified by the print job on the sheet 9.

[0054] The heater power supply circuit 86 supplies power in an amount corresponding to the input unit power command to the unit heater 36.

[0055] The CPU 81 includes a plurality of processing modules realized by executing the computer program. The plurality of processing modules include a main control unit 8a, a conveyance control unit 8b, a print control unit 8c, a temperature control unit 8d, and the like.

[0056] The main control unit 8a executes control to start various processes in response to a processing request input through the operation device 801 or the communication device 85, and control of the display device 802.

[0057] The conveyance control unit 8b controls the sheet conveyance device 2. That is, the conveyance control unit 8b controls the supply of the sheet 9 by the feeding mechanism 21, the conveyance of the sheet 9 by the plurality of sets of conveyance roller pairs 22 and the belt conveyance mechanism 23, and the discharge of the sheet 9 by the discharge roller pair 24.

[0058] The print control unit 8c causes the print unit 3 to execute the print process in synchronization with the conveyance of the sheet 9 by the sheet conveyance device 2. The print control unit 8c causes the print unit 3 to execute the print process by controlling a plurality of piezoelectric elements 33.

[0059] The temperature control unit 8d controls the power supplied to the unit heater 36 by outputting the signal of the unit power command to the heater power supply circuit 86 through the signal interface 84.

[0060] Incidentally, each nozzle unit 30 includes a drive circuit 300 that supplies the drive signal to each piezoelectric element 33 (see FIG. 1).

[0061] The drive circuit 300 outputs the drive signal to each piezoelectric element 33 according to the input pressurization command signal. Each nozzle unit 30 forms an image on the sheet 9 with the ink ejected from the plurality of nozzles 32 by supplying the drive signal to the plurality of piezoelectric elements 33 from the drive circuit 300.

[0062] The print control unit 8c outputs the signal of the pressurization command according to the size of the ink droplets to be ejected from each nozzle 32 to the drive circuit 300 through the signal interface 84. The print control unit 8c controls each piezoelectric element 33 through the drive circuit 300.

[0063] The drive circuit 300 generates heat when the state of outputting the drive signal continues. When the drive circuit 300 generates heat, the temperature of each nozzle unit 30 rises.

[0064] When the inkjet recording apparatus 10 is executing continuous print processing, it is necessary to suppress excessive temperature rise of each nozzle unit 30 due to heat generation of the drive circuit 300. Therefore, the inkjet recording apparatus 10 includes a cooling device 51 (see FIG. 1).

[0065] The cooling device 51 cools each of the nozzle units 30 with a refrigerant liquid. For example, the refrigerant liquid is water. The cooling device 51 includes a pump 51a that circulates the refrigerant liquid and a radiator 51b that releases the heat of the refrigerant liquid (see FIG. 1). The pump 51a circulates the coolant in a circulation path that passes through each of the nozzle units 30 and the radiator 51b.

[0066] On the other hand, while suppressing the power consumption of each of the nozzle units 30 and the cooling device 51, it is required that the first print time can be shortened.

[0067] The inkjet recording apparatus 10 is provided with a configuration for shortening the first print time while suppressing the power consumption of each of the nozzle units 30 and the cooling device 51. Hereinafter, the configuration will be described.

[0068] The inkjet recording apparatus 10 further includes a peripheral heater 52 and a peripheral temperature sensor 53 (see FIG. 1). The inkjet recording apparatus 10 includes one peripheral heater 52 and one peripheral temperature sensor 53 corresponding to a plurality of nozzle units 30.

[0069] The peripheral heater 52 heats the peripheries of the plurality of nozzle units 30. The peripheral temperature sensor 53 detects the temperature of the peripheries of the plurality of nozzle units 30. For example, the peripheral temperature sensor 53 is a thermistor.

[0070] The unit heater 36 is an example of a first heater that heats the ink ejection portion 31 of each of the nozzle units 30. The peripheral heater 52 is an example of a second heater that heats a plurality of nozzle units 30 from the outside.

[0071] The unit temperature sensor 37 is an example of a first temperature sensor that detects the temperature of each of the nozzle units 30. The peripheral temperature sensor 53 is an example of a second temperature sensor that detects the temperature outside a plurality of nozzle units 30.

[0072] The heater power supply circuit 86 supplies power to the peripheral heater 52 in an amount corresponding to the input peripheral power command. The temperature control unit 8d controls the power supplied to the peripheral heater 52 by outputting a signal of the peripheral power command to the heater power supply circuit 86 through the signal interface 84.

[0073] The temperature control unit 8d controls the power supplied to each of the unit heater 36 and the peripheral heater 52, and also controls the cooling device 51. Further, the temperature control unit 8d controls the power supply to and the power supply stop of the drive circuit 300.

[0074] In the following description, the temperature detected by the unit temperature sensor 37 is referred to as the first detected temperature, and the temperature detected by the peripheral temperature sensor 53 is referred to as the second detected temperature.

[0075] The temperature control unit 8d adjusts the power supplied to the unit heater 36 by first temperature feedback control based on the first detected temperature and the first target temperature.

[0076] Furthermore, the temperature control unit 8d adjusts the power supplied to the peripheral heater 52 by second temperature feedback control based on the second detected temperature and the second target temperature.

[0077] [Device Temperature Control] Hereinafter, an example of the procedure of device temperature control by the temperature control unit 8d will be described with reference to the flowchart shown in FIG. 4.

[0078] The temperature control unit 8d starts the device temperature control when the CPU 81 is activated. The device temperature control is an example of a process for realizing a control method for the unit heater 36, the peripheral heater 52, the cooling device 51, and the drive circuit 300. The CPU 81 including the temperature control unit 8d is an example of a processor for realizing the control method.

[0079] In the following description, S101, S102, ··· are codes for identifying each of a plurality of steps in the device temperature control. In the device temperature control, first, the process of step S101 is executed.

[0080] When the device temperature control is started, the power supply to the drive circuit 300 and the unit heater 36 in each of the nozzle units 30, and the power supply to the peripheral heater 52 and the cooling device 51 are stopped.

[0081] <Step S101> In step S101, the temperature control unit 8d adjusts the power supply to the peripheral heater 52 by executing the second temperature feedback control.

[0082] The temperature control unit 8d continues the second temperature feedback control after step S101.

[0083] The temperature control unit 8d executes the second temperature feedback control (step S101) during the period from when the CPU 81 starts up to when the print request is received. As a result, each of the nozzle units 30 is warmed to such an extent that it does not deteriorate due to the heat load. As a result, the first print time when the print request occurs is shortened.

[0084] Also, in a situation where each of the nozzle units 30 does not consume power and each of the nozzle units 30 is heated from the outside by the peripheral heater 52, cooling by the cooling device 51 is unnecessary. The second temperature feedback control in step S101 is executed in a state where the power supply to the drive circuit 300 and the unit heater 36 in each of the nozzle units 30 and the power supply to the cooling device 51 are stopped. Therefore, the power consumption during the period from when the CPU 81 starts up to when the print request is received is low.

[0085] After executing the process of step S101, the temperature control unit 8d executes the process of step S102.

[0086] <Step S102> In Step S102, the temperature control unit 8d waits until it receives a print request through the communication device 85 or the operation device 801. The print request is an image formation request.

[0087] When the temperature control unit 8d receives the print request, it executes the process of Step S103.

[0088] <Step S103> In Step S103, the temperature control unit 8d executes a request response process (see FIG. 5).

[0089] The request response process is a process of adjusting the temperature of each nozzle unit 30 to a temperature at which printing is possible and then outputting a print permission. The print control unit 8c executes the print process corresponding to the print request on the condition that the print permission is output.

[0090] After executing the process of Step S103, the temperature control unit 8d executes the process of Step S104.

[0091] <Step S104> In Step S104, the temperature control unit 8d executes a post-permission process described below. The post-permission process is a process of maintaining each nozzle unit 30 in an appropriate state after the print permission is output.

[0092] When the temperature control unit 8d finishes the post-permission process, it ends the device temperature control.

[0093] [Request Response Process] Next, an example of the procedure of the request response process by the temperature control unit 8d will be described with reference to the flowchart shown in FIG. 5.

[0094] In the following description, S201, S202,... are symbols for identifying each of the plurality of steps in the request response process. In the request response process, first, the process of Step S201 is executed.

[0095] <Step S201> In step S201, the temperature control unit 8d adjusts the power supply to the unit heater 36 by executing the first temperature feedback control.

[0096] After executing the process of step S201, the temperature control unit 8d executes the process of step S202.

[0097] <Step S202> In step S202, the temperature control unit 8d waits until the first detected temperature becomes equal to or higher than a preset reference temperature. For example, the reference temperature is the first target temperature or a temperature within a target range based on the first target temperature.

[0098] When the request response process is executed, the second temperature feedback control has already been executed. As a result, the time until the first detected temperature becomes equal to or higher than the reference temperature is shortened.

[0099] When the first detected temperature becomes equal to or higher than the reference temperature, the temperature control unit 8d executes the process of step S203.

[0100] <Step S203> In step S203, the temperature control unit 8d outputs the print permission to the print control unit 8c. The print control unit 8c executes the print process corresponding to the print request according to the print permission.

[0101] After executing the process of step S203, the temperature control unit 8d ends the request response process. The temperature control unit 8d executes the post - permission process following the request response process (see steps S104 in FIG. 4 and FIG. 6).

[0102] [Post - permission process] Next, while referring to the flowchart shown in FIG. 6, an example of the procedure of the post-permission process by the temperature control unit 8d will be described. The post-permission process is executed under the situation where the first temperature feedback control is being executed.

[0103] In the following description, S301, S302, ··· are codes for identifying each of the plurality of steps in the post-permission process. In the post-permission process, first, the process of step S301 is executed.

[0104] <Step S301> In step S301, the temperature control unit 8d selects the next process according to whether the first detected temperature exceeds a preset allowable temperature. The allowable temperature is higher than the first target temperature.

[0105] The allowable temperature is the upper limit of the appropriate temperature range for each of the nozzle units 30 when the printing process is being executed.

[0106] When the first detected temperature exceeds the allowable temperature, the temperature control unit 8d executes the process of step S302. On the other hand, when the first detected temperature does not exceed the allowable temperature, the temperature control unit 8d executes the process of step S306.

[0107] <Step S302> In step S302, the temperature control unit 8d activates the cooling device 51. Thereby, cooling of each of the nozzle units 30 by the cooling device 51 is executed.

[0108] After executing the process of step S302, the temperature control unit 8d executes the process of step S303.

[0109] <Step S303> In step S303, the temperature control unit 8d selects the next process according to whether the first detected temperature is lower than a preset set temperature.

[0110] When the first detected temperature is lower than the set temperature, the temperature control unit 8d executes the process of step S305. On the other hand, when the first detected temperature is not lower than the set temperature, the temperature control unit 8d executes the process of step S304.

[0111] <Step S304> In step S304, the temperature control unit 8d selects the following process according to whether the first detected temperature exceeds a preset upper limit temperature.

[0112] When the first detected temperature does not exceed the upper limit temperature, the temperature control unit 8d executes the process of step S303. On the other hand, when the first detected temperature exceeds the upper limit temperature, the temperature control unit 8d executes the process of step S308.

[0113] That is, the temperature control unit 8d repeats the processes of step S303 and step S304 until the first detected temperature is lower than the set temperature or the first detected temperature exceeds the upper limit temperature.

[0114] <Step S305> In step S305, the temperature control unit 8d stops the operation of the cooling device 51. Further, the temperature control unit 8d may stop the power supply to the cooling device 51.

[0115] After executing the process of step S305, the temperature control unit 8d executes the process of step S306.

[0116] <Step S306> In step S306, the temperature control unit 8d selects the following process according to whether the printing process corresponding to the printing permission has ended.

[0117] When the printing process has not ended, the temperature control unit 8d repeats the processes after step S301. On the other hand, when the printing process has ended, the temperature control unit 8d executes the process of step S307.

[0118] <Step S307> In step S307, the temperature control unit 8d executes post-print processing (see FIG. 7). The post-print processing is processing from after the print processing is completed until the next print request occurs.

[0119] As described later, the post-print processing ends when the inkjet recording apparatus 10 receives the next print request. When the post-print processing ends, the temperature control unit 8d executes the processing after step S301.

[0120] <Step S308> On the other hand, in step S308, the temperature control unit 8d executes error processing. The error processing includes processing to stop the print processing, processing to stop power supply to the unit heater 36 and the peripheral heater 52, and processing to output an error message.

[0121] For example, the temperature control unit 8d outputs the error message to the display device 802 and the host device that is the transmission source of the print request. Even after executing the error processing, the temperature control unit 8d continues the operation of the cooling device 51.

[0122] After executing the processing of step S308, the temperature control unit 8d ends the post-permission processing. Thereby, the device temperature control ends.

[0123] [Post-Print Processing] Next, an example of the procedure of the post-print processing by the temperature control unit 8d will be described with reference to the flowchart shown in FIG. 7.

[0124] In the following description, S401, S402,... are symbols for identifying each of a plurality of steps in the post-print processing. In the post-print processing, first, the processing of step S401 is executed.

[0125] <Step S401> In step S401, the temperature control unit 8d selects the following processing according to whether or not a rest condition is satisfied, including not receiving the print request.

[0126] The first example of the rest condition is the condition that the state of not receiving the print request continues for a preset time. Further, the second example of the rest condition is the condition that the print request has not been received and a rest request has been received through the operation device 801 or the communication device 85.

[0127] When the rest condition is not satisfied, the temperature control unit 8d executes the processing of step S402. On the other hand, when the rest condition is satisfied, the temperature control unit 8d executes the processing of step S403.

[0128] <Step S402> In step S402, the temperature control unit 8d selects the following processing according to whether or not the print request has been received.

[0129] When the temperature control unit 8d has not received the print request, it executes the processing of step S401. On the other hand, when the temperature control unit 8d has received the print request, it executes the processing of step S408.

[0130] That is, the temperature control unit 8d repeats the processing of steps S401 and S402 until the rest condition is satisfied or until the print request is received.

[0131] <Step S403> In step S403, the temperature control unit 8d stops the power supply to the unit heater 36 and the drive circuit 300 of each nozzle unit 30. In step S403, the temperature control unit 8d may stop the power supply to the cooling device 51.

[0132] Hereinafter, the state in which the power supply to the unit heater 36 and the drive circuit 300 of each nozzle unit 30 is stopped is referred to as a rest state. By executing the processing of step S403, each nozzle unit 30 enters the rest state.

[0133] After executing the process of step S403, the temperature control unit 8d executes the process of step S404.

[0134] <Step S404> In step S404, the temperature control unit 8d waits until it receives the print request. The processes of steps S403 to S404 are executed in a situation where each of the nozzle units 30 is in the rest state.

[0135] When the temperature control unit 8d receives the print request, it executes the process of step S405.

[0136] <Step S405> In step S405, the temperature control unit 8d executes the request response process (see FIG. 5). Thereby, when the temperature control unit 8d receives the image formation request in a situation where each of the nozzle units 30 is in the rest state, it starts the process of step S201 (see step S201 in FIG. 5).

[0137] After executing the request response process, the temperature control unit 8d ends the post-print process.

[0138] By adopting the inkjet recording apparatus 10, it is possible to shorten the first print time while suppressing the power consumption of the plurality of nozzle units 30 and the cooling device 51.

[0139] [Modification Example] Next, a modification example of the device temperature control will be described.

[0140] In this modification example, the temperature control unit 8d ends the second temperature feedback control after the first temperature feedback control of the request response process is started and before the first detected temperature reaches the reference temperature.

[0141] That is, the temperature control unit 8d in this modification example stops the power supply to the peripheral heater 52 under the situation where the first temperature feedback control is being executed.

[0142] For example, when the first detected temperature reaches the first set temperature, the temperature control unit 8d ends the second temperature feedback control and stops the power supply to the peripheral heater 52. The first set temperature is lower than the reference temperature.

[0143] Furthermore, the temperature control unit 8d in this modification example resumes the second temperature feedback control after the rest condition is satisfied in the post-print processing. For example, when the second detected temperature falls below a preset second set temperature, the temperature control unit 8d resumes the second temperature feedback control.

[0144] That is, the temperature control unit 8d in this modification example waits until the second detected temperature falls below the second set temperature in the rest state and then starts adjusting the power supply to the peripheral heater 52 by the second temperature feedback control.

[0145] When this modification example is adopted, the same effects as when the above embodiment is adopted can be obtained.

Explanation of Reference Numerals

[0146] 2: Sheet conveying device 3: Printing unit 4: Ink supply unit 8: Control device 10: Inkjet recording device 30: Nozzle unit 31: Ink ejection unit 32: Nozzle 33: Piezoelectric element 36: Unit heater (first heater) 37: Unit temperature sensor (first temperature sensor) 51: Cooling device 52: Peripheral heater (second heater) 53: Peripheral temperature sensor (second temperature sensor) 300: Drive circuit

Claims

1. A nozzle unit having a plurality of nozzles, a plurality of piezoelectric elements corresponding to the plurality of nozzles, a first heater, a first temperature sensor, and a drive circuit capable of supplying a drive signal to the plurality of piezoelectric elements, and forming an image on a sheet by ink ejected from the plurality of nozzles by supplying the drive signal to the plurality of piezoelectric elements, A second heater for heating the nozzle unit from the outside, A cooling device for cooling the nozzle unit with a refrigerant liquid, A second temperature sensor for detecting the temperature outside the nozzle unit, A control unit for controlling the first heater, the drive circuit, the second heater, and the cooling device, The control unit adjusts the power supplied to the first heater by first temperature feedback control based on a first detected temperature detected by the first temperature sensor and a first target temperature, Furthermore, the control unit operates the cooling device when the first detected temperature exceeds an allowable temperature under the condition that the first temperature feedback control is being executed, Furthermore, the control unit stops the power supply to the first heater and the drive circuit when a rest condition including not receiving an image formation request is satisfied under the condition that the first temperature feedback control is being executed, Furthermore, the control unit adjusts the power supplied to the second heater by second temperature feedback control based on a second detected temperature detected by the second temperature sensor and a second target temperature in a rest state where the power supply to the first heater and the drive circuit is stopped, Furthermore, the control unit starts adjusting the power supplied to the first heater by the first temperature feedback control when an image formation request is received in the rest state, an inkjet recording apparatus.

2. The control unit stops the power supply to the cooling device when the first detected temperature is lower than a preset temperature under the condition that the first temperature feedback control is being executed, the inkjet recording apparatus according to claim 1.

3. The control unit stops the power supply to the second heater under the condition that the first temperature feedback control is being executed, Furthermore, the control unit waits until the second detected temperature falls below a preset temperature in the standby state and then starts adjusting the power supplied to the second heater by the second temperature feedback control. The inkjet recording apparatus according to claim 1 or claim 2.

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