JP2011068013A - Printing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing apparatus capable of shortening a time for raising an ink temperature to an appropriate temperature. <P>SOLUTION: A perfecting printing apparatus 1 includes: a circulating part 19 having an electromagnetic valve 27 switching either a heating circulating path C1-C2 for circulating ink 50 while it is heated by a heater 28 or a cooling circulating path C1-C3 for circulating the ink while it is cooled by a cooler 29; a peripheral temperature sensor 7 for measuring a peripheral temperature Ta and outputting it; and a control part 8 for setting the circulating path of the ink 50 by controlling the electromagnetic valve 27 based on the peripheral temperature Ta input from the peripheral temperature sensor 7 after image printing is finished. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a printing apparatus that cools and heats ink.

  2. Description of the Related Art Conventionally, a printing apparatus including an inkjet head that ejects ink is known. In such a printing apparatus, the viscosity of the ink greatly affects the ejection of the ink.

  In view of this, Japanese Patent Application Laid-Open No. 2004-228561 discloses a printing apparatus that allows the user to set the image density according to the use environment temperature. Patent Document 2 discloses a printing apparatus that circulates and refreshes ink.

  However, it is difficult to say that the viscosity of the ink is sufficiently controlled by the technique of the above-described patent document. Accordingly, it has been proposed to provide means for adjusting the temperature of the ink, such as a heater or a fan, in the middle of the ink supply path. Thereby, this printing apparatus can adjust the ink to an appropriate temperature, and can maintain the viscosity of the ink appropriately.

JP 2004-276486 A JP 2006-88575 A

  However, in the technique described above, when image printing is completed and the heater and fan are stopped, the ink reaches room temperature in a short time. For this reason, when starting the next image printing, there exists a subject that time for making ink temperature suitable temperature becomes long.

  SUMMARY An advantage of some aspects of the invention is that it provides a printing apparatus that can shorten the time required to set the ink temperature to an appropriate temperature.

  In order to achieve the above object, the invention according to claim 1 is provided in any one of a heating circulation path for circulating ink while being heated by a heating means, or a cooling circulation path for circulating ink while being cooled by a cooling means. A circulation unit having a switching unit for switching, an ambient temperature measuring unit for measuring and outputting the ambient temperature, and controlling the switching unit based on the ambient temperature input from the ambient temperature measuring unit after the image printing is completed. And a control unit for setting an ink circulation path.

  According to a second aspect of the present invention, the controller sets the switching means to the heating circulation path side when the ambient temperature is equal to or lower than the appropriate lower limit temperature of the ink after the image printing is finished, and the ambient temperature Is equal to or higher than the appropriate upper limit temperature of the ink, the switching means is set to the cooling circulation path side.

  The invention according to claim 3 further includes an ink temperature measuring unit that measures and outputs an ink temperature, and the control unit, after the end of image printing, has the ambient temperature within an appropriate temperature range of the ink, and When the ink temperature input from the ink temperature measuring means is equal to or higher than the threshold temperature within the appropriate temperature range of the ink, the switching means is set to the cooling circulation path side, and the ambient temperature is within the appropriate temperature range of the ink, In addition, when the ink temperature input from the ink temperature measuring unit is lower than the threshold temperature within the appropriate temperature range of the ink, the switching unit is set to the heating circulation path side.

  The invention according to claim 4 is characterized in that the control section stops the cooling means or the heating means after setting the switching means.

  The invention according to claim 5 is characterized in that a path length of the heating circulation path is shorter than a path length of the cooling circulation path.

  According to the first aspect of the present invention, after the image printing is finished, the control unit controls the switching means based on the ambient temperature to set the ink circulation path. Thereby, the ink temperature is adjusted by the residual heat of the heating means or the heat radiation of the cooling means. As a result, according to the first aspect of the present invention, it is possible to shorten the time required for setting the ink temperature to an appropriate temperature.

  According to the second aspect of the present invention, after the image printing is completed, the control unit sets the switching means to the heating circulation path side when the ambient temperature is equal to or lower than the appropriate temperature lower limit temperature of the ink. Thereby, even when the ambient temperature is low, the ink can be heated by the residual heat of the heating means. According to the invention of claim 2, after the image printing is finished, the control unit sets the switching means to the cooling circulation path side when the ambient temperature is equal to or higher than the appropriate upper temperature limit of the ink. Thereby, even when the ambient temperature is high, the ink can be cooled by the cooling means.

  According to the invention of claim 3, after the end of image printing, the control unit sets the switching means to the cooling circulation path side when the ink temperature is equal to or higher than the threshold temperature. Thus, when the ink temperature is a high temperature within the appropriate temperature range, it is possible to suppress the ink from being heated by the heating unit. According to the invention of claim 3, after the image printing is finished, the control unit sets the switching means to the heating circulation path side when the ink temperature is lower than the threshold temperature. Thereby, when the ink temperature is a low temperature within the appropriate temperature range, it is possible to suppress the ink from being cooled by the cooling means.

  According to the invention of claim 4, by stopping the cooling means after setting the switching means, it is possible to suppress the ink from being heated by the ambient temperature even when the ambient temperature is higher than the appropriate temperature range. In other words, when the cooling unit is stopped before the setting of the switching unit, the heating of the ink by the ambient temperature starts earlier, but this heating can be delayed and suppressed by delaying the stop of the cooling unit. it can. According to the invention of claim 4, by stopping the heating means after setting the switching means, it is possible to suppress the ink from being cooled by the ambient temperature even when the ambient temperature is lower than the appropriate temperature range. it can. In other words, when the heating unit is stopped before the setting of the switching unit, ink cooling by the ambient temperature starts earlier, but this cooling can be delayed and suppressed by delaying the stop of the heating unit. it can.

  According to the invention of claim 5, by making the heating circulation path shorter than the cooling circulation path, it is possible to reduce that the heated ink dissipates heat during circulation.

1 is an overall schematic diagram of a duplex printing apparatus according to a first embodiment. It is the schematic of a printing part. It is a block diagram for demonstrating the control system of a duplex printing apparatus. 6 is a flowchart for explaining printing processing by a duplex printing apparatus. It is a flowchart explaining a circulation stop process. It is a flowchart explaining the circulation stop process by 2nd Embodiment. It is a flowchart explaining the circulation stop process by 3rd Embodiment.

(First embodiment)
Hereinafter, an inkjet double-sided printing device according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an overall schematic diagram of a duplex printing apparatus according to a first embodiment. FIG. 2 is a schematic diagram of the printing unit. FIG. 3 is a block diagram for explaining a control system of the duplex printing apparatus. In the following description, the paper surface direction of FIG. Moreover, as shown in FIG. 1, when viewed from the user, the top, bottom, left, and right are defined as the top, bottom, left, and right directions.

  Note that a path indicated by a thick line in FIG. 1 is a transport path through which the printing paper is transported. A route indicated by a solid line among the transport routes is a normal route RC. The route indicated by the alternate long and short dash line in the transport route is the reverse route RR. A path indicated by a two-dot chain line in the transport path is a paper feed path RS.

  As shown in FIG. 1, the duplex printing apparatus 1 includes a paper feeding unit 2, a conveyance printing unit 3, a conveyance unit 4, a paper discharge unit 5, a reversing unit 6, an ambient temperature sensor 7, and a control unit 8. And a housing 9 for storing each part.

  The paper feeding unit 2 feeds the printing paper PA. The paper feed unit 2 is arranged on the most upstream side of the transport path. The paper feed unit 2 includes a plurality of paper feed stands 11 and a plurality of pairs of paper feed rollers 12. The paper feed roller 12 transports the printing paper PA from one of the paper feed trays 11 along the paper feed path RS and feeds it to the transport printing unit 3.

  The conveyance printing unit 3 prints an image on the printing paper PA while conveying the printing paper PA. The transport printing unit 3 is disposed on the downstream side of the paper feed unit 2 in the transport path. The conveyance printing unit 3 includes a registration roller 15, a belt conveyance unit 16, and a printing unit 17.

  The registration roller 15 conveys the printing paper PA conveyed from the paper feeding unit 2 or the reversing unit 6 to the belt conveyance unit 16. The belt conveyance unit 16 conveys the printing paper PA conveyed from the registration roller 15 to the conveyance unit 4 while sucking the printing paper PA.

  The printing unit 17 prints an image by ejecting the ink 50 while circulating it. The printing unit 17 is disposed above the belt conveyance unit 16 so as to face the belt conveyance unit 16. In FIG. 2, a path indicated by an arrow C0 is an ink supply path. The paths indicated by arrows C1 and C2 are heating circulation paths C1-C2 for circulating ink while heating. The paths indicated by arrows C1 and C3 are cooling circulation paths C1-C3 that circulate ink while cooling. As shown in FIG. 2, the printing unit 17 includes a supply unit 18, a circulation unit 19, and an inkjet head 20.

  The supply unit 18 supplies the ink 50 to the circulation unit 19. The supply unit 18 includes an ink bottle 22 and a supply pipe 23. Ink bottle 22 stores ink 50 for supply. One end of the supply pipe 23 is connected to the ink bottle 22. The other end of the supply pipe 23 is connected to the lower tank 25.

  The circulation unit 19 adjusts the ink temperature Ti by heating or cooling the ink 50 while circulating the ink 50. The circulation unit 19 includes a lower tank 25, a circulation pump 26, a solenoid valve (corresponding to the switching means in claims) 27, a heater 28, a cooler 29, an upper tank 30, and a flow path for the ink 50. Circulating pipes 31a to 31f to be formed are provided.

  The lower tank 25 temporarily stores the ink 50 supplied from the ink bottle 22 through the supply pipe 23. The lower tank 25 temporarily stores the ink 50 discharged from the inkjet head 20 via the circulation pipe 31f. The lower tank 25 is disposed below the upper tank 30 and the inkjet head 20.

  The circulation pump 26 circulates the ink 50. The circulation pump 26 is provided in the middle of a circulation pipe 31 a that connects the lower tank 25 and the electromagnetic valve 27. The ink 50 stored in the lower tank 25 by the circulation pump 26 circulates in the heating circulation path C1-C2 or the cooling circulation path C1-C3 shown in FIG.

  The electromagnetic valve 27 switches the circulation path of the ink 50 to either the heating circulation path C1-C2 or the cooling circulation path C1-C3. One liquid supply port of the electromagnetic valve 27 is connected to the heater 28 via the circulation pipe 31b. The other liquid supply port of the electromagnetic valve 27 is connected to the cooler 29 via the circulation pipe 31c.

The heater 28 heats the ink 50 circulating through the heating circulation path C1-C2. Heater 28 is provided between the upstream end of the heating-side upstream pipe portion 31d ₁ of the circulation pipe 31d to be described later with the downstream end of the circulation pipe 31b.

The cooler 29 cools the ink 50 circulating through the cooling circulation path C1-C3. The cooler 29 includes a heat sink 29a and a cooling fan 29b. The heat sink 29a is provided between the upstream end of the cooling-side upstream pipe portion 31d ₂ of the circulation pipe 31d to be described later with the downstream end of the circulation pipe 31c. The cooling fan 29b blows air to the heat sink 29a. Thereby, the heat dissipation of the heat sink 29a improves.

  The upper tank 30 temporarily stores the ink 50 to be supplied to the inkjet head 20. The upper tank 30 is filled with air together with the ink 50. The upper tank 30 is disposed above the inkjet head 20 and the lower tank 25. As a result, the ink 50 stored in the upper tank 30 flows to the inkjet head 20 and the lower tank 25 due to the water head difference.

  The circulation pipe 31 a connects the lower tank 25 and the electromagnetic valve 27. The circulation pipe 31 b connects one liquid feeding port of the electromagnetic valve 27 and the heater 28. The circulation pipe 31 c connects the other liquid feeding port of the electromagnetic valve 27 and the cooler 29.

Circulation pipe 31d includes a heating side upstream tube portion 31d _1, and the cooling side upstream pipe portion 31d _2, and a junction pipe 31d _3. The downstream end of the downstream end of the heating-side upstream pipe portion 31d ₁ and the cooling side upstream pipe portion 31d ₂ is connected to the junction pipe 31d ₃ merge to. Upstream end of the heating-side upstream pipe portion 31d ₁ is connected to the heater 28. The upstream end of the cooling side upstream pipe portion 31 d ₂ is connected to the heat sink 29 a of the cooler 29. Downstream end of the confluence pipe 31d ₃ is connected to the upper tank 30.

  The circulation pipe 31 e connects the upper tank 30 and the inkjet head 20. The circulation pipe 31 f connects the inkjet head 20 and the lower tank 25.

Heating circulation path C1-C2 as described above through the heating side upstream pipe portion 31d ₁ of the circulation pipe 31d, the cooling circulation path C1-C3 is via a cooling-side upstream pipe portion 31d ₂ of the circulation pipe 31d. The path length of the heater path C2 is configured to be shorter than the path length of the cooler path C3. For this reason, the heating circulation path C1-C2 is shorter than the cooling circulation path C1-C3.

  The ink jet head 20 discharges the ink 50 circulating through the circulation unit 19 onto the printing paper PA. The inkjet head 20 is disposed below the upper tank 30. The inkjet head 20 includes a piezoelectric member that applies pressure for ejecting the ink 50. During the ink circulation, the ink 50 accumulated in the inkjet head 20 flows to the lower tank 25 through the circulation pipe 31f. The inkjet head 20 has an ink temperature sensor 32.

  The ink temperature sensor 32 measures the ink temperature Ti of the ink 50 inside the inkjet head 20. The ink temperature sensor 32 outputs the measured ink temperature Ti to the control unit 8.

  The transport unit 4 transports the printed printing paper PA while drying it. The transport unit 4 is disposed on the downstream side of the transport printing unit 3. The transport unit 4 includes a plurality of pairs of transport rollers 35 arranged along the normal route RC.

  The paper discharge unit 5 discharges printed printing paper PA and stacks it. The paper discharge unit 5 is disposed on the most downstream side of the normal route RC. The paper discharge unit 5 includes a switching mechanism 37, two pairs of paper discharge rollers 38, and a paper discharge table 39. The switching mechanism 37 switches the conveyance path of the printing paper PA between the normal path RC and the reverse path RR for double-sided printing. The paper discharge roller 38 discharges the printing paper PA to the paper discharge table 39.

  The reversing unit 6 reverses the printing paper PA on which one side is printed and transports it to the transport printing unit 3. The reversing unit 6 includes a plurality of pairs of reversing rollers 41, a flipper 42, and a switchback unit 43. The reversing roller 41 once conveys the printing paper PA, which has been printed on one side, conveyed from the conveying unit 4 to the switchback unit 43 via the switching mechanism 37. Further, the reverse roller 41 conveys the printing paper PA returned from the switchback unit 43 to the conveyance printing unit 3 via the flipper 42.

  The ambient temperature sensor 7 measures the ambient temperature Ta and outputs it to the control unit 8. The ambient temperature Ta is the temperature inside the housing 9. The ambient temperature sensor 7 is attached to the housing 9.

  The control unit 8 governs overall control of the duplex printing apparatus 1. As shown in FIG. 3, the control unit 8 stores a CPU 51 that executes various programs, a RAM 52 that temporarily stores information, a ROM 53 that stores basic programs, and a printing program. HDD 54 and an I / O port 55 for performing input / output are provided.

  The HDD 54 stores an appropriate temperature upper limit temperature Tu, an appropriate temperature lower limit temperature Td, and a threshold temperature ThT. Here, the appropriate temperature is a temperature at which the ink 50 has an appropriate viscosity and can assure proper ejection of the ink 50. The appropriate temperature upper limit Tu is the upper limit temperature (for example, 40 ° C.) of the appropriate temperature. That is, it is necessary to cool the ink 50 before the ink temperature Ti becomes higher than the appropriate temperature upper limit temperature Tu. The appropriate temperature lower limit temperature Td is the lower limit temperature (for example, 20 ° C.) of the appropriate temperature. That is, it is necessary to heat the ink 50 before the ink temperature Ti becomes lower than the appropriate temperature lower limit temperature Td. The threshold temperature ThT is a predetermined temperature within an appropriate temperature range. In the present embodiment, the center temperature is set to an appropriate temperature (for example, 30 ° C.).

  The I / O port 55 is connected to the paper feed unit 2, the transport printing unit 3, the transport unit 4, the paper discharge unit 5, and the reversing unit 6 so that input / output is possible. The I / O port 55 is connected to an external device (not shown) such as a personal computer for inputting image data. Thus, when image data is input, the control unit 8 controls the paper feeding unit 2, the conveyance printing unit 3, the conveyance unit 4, the paper discharge unit 5, and the reversing unit 6 to perform single-sided printing or double-sided printing. Execute.

  The I / O port 55 is connected to the registration roller 15, the belt conveyance unit 16 and the printing unit 17 of the conveyance printing unit 3, and the ambient temperature sensor 7. Specifically, the inkjet head 20 of the printing unit 17, the circulation pump 26, the electromagnetic valve 27, the heater 28, the cooling fan 29 b, and the ink temperature sensor 32 are connected to the I / O port 55.

  Thereby, when starting image printing, the controller 8 controls the heater 28 or the cooling fan 29b while driving the circulation pump 26 to circulate the ink 50. As a result, the ink temperature Ti is adjusted to an appropriate temperature.

  Further, the control unit 8 outputs an ejection signal corresponding to the image data to the inkjet head 20 when printing an image. As a result, the inkjet head 20 discharges the droplets of the ink 50 corresponding to the image data onto the printing paper PA.

  Further, when the ambient temperature Ta is input from the ambient temperature sensor 7 after the image printing is finished, the control unit 8 controls the electromagnetic valve 27 based on the input ambient temperature Ta. Specifically, when the ambient temperature Ta is equal to or lower than the appropriate temperature lower limit temperature Td, the control unit 8 sets the electromagnetic valve 27 to the heating circulation path C1-C2 side. On the other hand, when the ambient temperature Ta is equal to or higher than the appropriate temperature upper limit temperature Tu, the control unit 8 sets the electromagnetic valve 27 to the cooling circulation path C1-C3 side.

  Further, when the ink temperature Ti is input from the ink temperature sensor 32 after the image printing is completed, the control unit 8 controls the electromagnetic valve 27 based on the input ink temperature Ti. Specifically, when the ink temperature Ti is equal to or higher than the threshold temperature ThT, the control unit 8 sets the electromagnetic valve 27 to the cooling circulation path C1-C3 side. On the other hand, when the ink temperature Ti is equal to or lower than the threshold temperature ThT, the control unit 8 sets the electromagnetic valve 27 to the heating circulation path C1-C2 side.

(Printing process)
Next, the printing process of the duplex printing apparatus 1 according to the first embodiment described above will be described. FIG. 4 is a flowchart for explaining printing processing by the duplex printing apparatus. FIG. 5 is a flowchart for explaining the circulation stop process. 4 and 5, the number after “S” indicates a step number.

  As shown in FIG. 4, when image data is input from an external personal computer or the like and print processing is started, the control unit 8 executes print initial processing (S1). This printing initial process includes ink circulation and temperature adjustment of the ink 50 in the printing unit 17 shown in FIG. Specifically, the control unit 8 switches to either the heating circulation path C1-C2 or the cooling circulation path C1-C3 based on the determination result obtained by comparing the ink temperature Ti with the appropriate temperature. Thereafter, the control unit 8 activates the circulation pump 26 to circulate the ink 50 in the heating circulation path C1-C2 or the cooling circulation path C1-C3, and the ink temperature Ti is set to an appropriate temperature by the heater 28 or the cooler 29. Adjust to.

  Next, when the initial printing operation is normally executed and the ink temperature Ti reaches an appropriate temperature, image printing is started while the ink circulation is continued (S2). The image printing operation will be described below with reference to FIG.

  First, when the image printing operation is started, unprinted printing paper PA is fed from one of the paper feed trays 11 to the transport printing unit 3 by a paper feed roller 12 along the paper feed path RS. . In the transport printing unit 3, the printing paper PA is transported to the belt transport unit 16 by the registration rollers 15. Then, the image is printed on the printing paper PA by the ink 50 ejected from the inkjet head 20 of the printing unit 17 while the printing paper PA is conveyed by the belt conveyance unit 16. Thereafter, the printing paper PA is transported to the transport unit 4 by the belt transport unit 16. In the transport unit 4, the printing paper PA is transported to the switching mechanism 37 of the paper discharge unit 5 by the transport roller 35.

  Here, in the case of single-sided printing, the printing paper PA is guided to the paper discharge roller 38 by the switching mechanism 37. Thereafter, the printing paper PA is discharged onto a paper discharge tray 39 by a paper discharge roller 38. Thereby, single-sided printing is completed.

  On the other hand, in the double-sided printing operation, the printing paper PA is guided to the reverse path RR by the switching mechanism 37. In the reversing unit 6, the printing paper PA is temporarily carried into the switchback unit 43 by the reversing roller 41 while being guided by the flipper 42. Thereafter, the printing paper PA returned from the switchback unit 43 is re-fed to the transport printing unit 3 by the reverse roller 41 while being guided by the flipper 42.

  In the transport printing unit 3, the printing paper PA is transported by the belt transport unit 16 in a state where the unprinted surface of the printing paper PA is directed to the inkjet head 20 side. As a result, the image is printed on the unprinted surface of the printing paper PA by the inkjet head 20. Thereafter, the double-side printed printing paper PA is transported to the paper discharge tray 39 by the transport unit 4 and the paper discharge unit 5. Thereby, the image is printed on both sides of the printing paper PA, and the double-sided printing is finished.

  Thereafter, when the control unit 8 determines that an image has been printed on the predetermined number of printing papers PA, the image printing ends (S3). Specifically, the control unit 8 stops the conveyance of the printing paper PA and stops the transmission of the ejection signal to the inkjet head 20.

  Next, the control unit 8 determines whether there is next image data (S4). If the control unit 8 determines that there is the next image data (S4: Yes), the control unit 8 ends the printing process without executing the ink circulation stop process. On the other hand, if the control unit 8 determines that there is no next image data (S4: No), it executes a circulation stop process for stopping the ink circulation shown in FIG. 5 (S5). Note that at the time when the circulation stop process is started, the ink temperature Ti is in the range of a substantially appropriate temperature because it is immediately after image printing.

  As shown in FIG. 5, when the ink circulation stop process is started, the controller 8 stops the heater 28 and the cooling fan 29b (S11). Thereby, heating and cooling of the ink 50 are completed. One of the heater 28 and the cooling fan 29b has already stopped, but in this case, the stopped state continues.

  Next, the control unit 8 stops the circulation pump 26 (S12). Thereafter, the ink 50 circulates by natural convection.

  Next, the control unit 8 determines whether or not the ambient temperature Ta input from the ambient temperature sensor 7 is equal to or lower than the appropriate temperature lower limit temperature Td (S13). When the controller 8 determines that the ambient temperature Ta is equal to or lower than the appropriate temperature lower limit temperature Td (S13: Yes), the controller 8 sets the electromagnetic valve 27 to the heating circulation path C1-C2 side (S14). Accordingly, the ink 50 that circulates in the heating circulation path C <b> 1-C <b> 2 by natural convection is heated by the residual heat of the heater 28.

  On the other hand, when determining that the ambient temperature Ta is not equal to or lower than the appropriate temperature lower limit temperature Td (S13: No), the control unit 8 determines whether the ambient temperature Ta is equal to or higher than the appropriate temperature upper limit temperature Tu (S15). When the control unit 8 determines that the ambient temperature Ta is equal to or higher than the appropriate temperature upper limit temperature Tu, the control unit 8 sets the electromagnetic valve 27 on the cooling circulation path C1-C3 side (S16). As a result, the ink 50 circulating in the cooling circulation path C1-C3 by natural convection is radiated by the cooler 29 and cooled.

  On the other hand, if the control unit 8 determines that the ambient temperature Ta is not equal to or higher than the appropriate upper temperature limit Td (S15: No), it determines whether or not the ink temperature Ti input from the ink temperature sensor 32 is equal to or higher than the threshold temperature ThT (S17). ). Here, the process of step S17 is executed when the determination results of step S13 and step S15 are “No”. This means that the process of step S17 is executed when the ambient temperature Ta is within the appropriate temperature range.

  When determining that the ink temperature Ti is equal to or higher than the threshold temperature ThT (S17: Yes), the control unit 8 sets the electromagnetic valve 27 to the cooling circulation path C1-C3 (S18). Thus, when the ambient temperature Ta is within the appropriate temperature range, the ink 50 having a temperature higher than the threshold temperature ThT circulating by natural convection is radiated and cooled by the cooler 29 without being heated by the residual heat of the heater 28. Is done.

  On the other hand, when determining that the ink temperature Ti is not equal to or higher than the threshold temperature ThT (S17: No), the control unit 8 sets the electromagnetic valve 27 to the heating circulation path C1-C2 (S19). Thus, when the ambient temperature Ta is within the appropriate temperature range, the ink 50 having a temperature lower than the threshold temperature ThT circulated by natural convection is heated by the residual heat of the heater 28 without being radiated by the cooler 29.

  When executing any one of the above-described steps S14, S16, S18, and S19, the control unit 8 ends the circulation stop process and ends the print process.

(Effect of printing device)
Next, effects of the double-sided printing apparatus 1 according to the first embodiment described above will be described.

  As described above, in the double-sided printing apparatus 1, after the image printing is finished, the control unit 8 controls the electromagnetic valve 27 based on the comparison between the ambient temperature Ta, the appropriate temperature lower limit temperature Td, and the appropriate temperature upper limit temperature Tu. Thereby, the residual heat of the heater 28 or the heat radiation by the cooler 29 can be used for adjusting the ink temperature Ti. As a result, the duplex printing apparatus 1 can shorten the time for adjusting the ink temperature Ti to an appropriate temperature at the start of the next printing.

  Specifically, when the ambient temperature Ta is equal to or lower than the appropriate temperature lower limit temperature Td, the control unit 8 sets the electromagnetic valve 27 on the heating circulation path C1-C2 side. As a result, even when the ambient temperature Ta is low, the ink 50 is heated by the residual heat of the heater 28, so that the ink temperature Ti within the substantially appropriate temperature range is unlikely to be the same as the ambient temperature Ta. As a result, the duplex printing apparatus 1 can shorten the time for setting the ink temperature Ti to an appropriate temperature at the start of the next printing. Further, the double-sided printing apparatus 1 can reduce power consumption by reducing driving of the heater 28 at the start of printing.

  Moreover, the control part 8 sets the solenoid valve 27 to the cooling circulation path | route C1-C3 side, when the ambient temperature Ta is more than the suitable temperature upper limit temperature Tu. As a result, even when the ambient temperature Ta is high, the ink 50 can be dissipated by the cooler 29, so that the ink temperature Ti within a substantially appropriate temperature range is unlikely to be the same as the ambient temperature Ta. As a result, the duplex printing apparatus 1 can shorten the time for setting the ink temperature Ti to an appropriate temperature at the start of the next printing. Further, the duplex printing apparatus 1 can reduce power consumption by reducing the driving of the cooler 29 at the start of printing.

  Further, when the ambient temperature Ta is within the appropriate temperature range, the control unit 8 controls the electromagnetic valve 27 based on the comparison between the threshold temperature ThT within the appropriate temperature range and the ink temperature Ti. Thereby, the remaining heat of the heater 28 or the heat radiation by the cooler 29 can be used for the adjustment of the ink temperature Ti, so that the time for adjusting the ink temperature Ti to an appropriate temperature at the start of the next printing can be shortened.

  Specifically, when the ink temperature Ti is equal to or higher than the threshold temperature ThT, the control unit 8 sets the electromagnetic valve 27 on the cooling circulation path C1-C3 side. As a result, when the ink temperature Ti is equal to or higher than the threshold temperature ThT, the ink 50 can be prevented from being heated by the residual heat of the heater 28, so the ink temperature Ti within the appropriate temperature range is unlikely to be outside the appropriate temperature range. As a result, the time for setting the ink temperature Ti to an appropriate temperature at the start of the next printing can be shortened.

  Further, when the ink temperature Ti is lower than the threshold temperature ThT, the control unit 8 sets the electromagnetic valve 27 on the heating circulation path C1-C2 side. Thereby, when the ink temperature Ti is lower than the threshold temperature ThT, it is possible to prevent the ink 50 from being dissipated by the cooler 29, so that the ink temperature Ti within the appropriate temperature range is unlikely to be outside the appropriate temperature range. As a result, the time for setting the ink temperature Ti to an appropriate temperature at the start of the next printing can be shortened.

  In the double-sided printing apparatus 1, the heater path C2 is configured to be shorter than the cooler path C3. Thereby, it can suppress that the ink 50 which needs a heating dissipates heat. Further, the ink 50 that needs to be cooled can dissipate more heat through the long cooler path C3.

(Second Embodiment)
Next, a second embodiment in which the circulation stop process of the above-described embodiment is changed will be described. FIG. 6 is a flowchart for explaining the circulation stop process according to the second embodiment. In addition, the same code | symbol is attached | subjected to the structure similar to embodiment mentioned above, and description is abbreviate | omitted. In addition, the same steps as those in the above-described embodiment are denoted by the same step numbers and description thereof is omitted.

  As shown in FIG. 6, in the circulation stop process according to the second embodiment, the controller 8 first stops the heater 28 (S21). Here, when the cooling fan 29b is driven, the driving of the cooling fan 29b is continued. Then, the control part 8 performs the process of step S12-step S19 similarly to 1st Embodiment. Next, the control unit 8 stops the cooling fan 29b (S22). Thereby, the circulation stop process by 2nd Embodiment is complete | finished.

  As described above, in the circulation stop process according to the second embodiment, the cooling fan 29b is stopped after the electromagnetic valve 27 is set. As a result, even when the ambient temperature Ta is high, the cooler 29 can be delayed from being warmed by the influence of the ambient temperature Ta, so that the ink 50 can be prevented from being warmed by the cooler 29. Moreover, the heater 28 with large power consumption can reduce power consumption by stopping substantially simultaneously with the start of the circulation stop process.

(Third embodiment)
Next, a third embodiment in which the circulation stop process of the above-described embodiment is changed will be described. FIG. 7 is a flowchart for explaining the circulation stop process according to the third embodiment. In addition, the same code | symbol is attached | subjected to the structure similar to embodiment mentioned above, and description is abbreviate | omitted. In addition, the same steps as those in the above-described embodiment are denoted by the same step numbers and description thereof is omitted.

  As shown in FIG. 7, in the circulation stop process according to the third embodiment, the control unit 8 executes the processes of step S21, step S13 to step S19, and step S22 as in the second embodiment. The circulation pump 26 executes the above processing without stopping. Next, the control unit 8 determines whether or not the threshold time ThM stored in the HDD 54 has elapsed since the start of the circulation stop process (S23). Here, the threshold time ThM is a time (for example, several minutes) at which the remaining heat of the heater 28 is dissipated to reach substantially the same temperature as the ambient temperature Ta.

  Next, when it is determined that the threshold time ThM has elapsed (S23: Yes), the control unit 8 stops the circulation pump 26 (S24). Thereby, the circulation of the ink 50 is stopped. As a result, the circulation stop process according to the third embodiment is completed.

  As described above, in the circulation stop process according to the third embodiment, the circulation pump 26 is continuously driven until the threshold time ThM has elapsed. Thereby, when the ink 50 circulates through the heating circulation path C <b> 1-C <b> 2 with the residual heat of the heater 28 remaining, the residual heat of the heater 28 can be used more efficiently.

  As mentioned above, although this invention was demonstrated in detail using embodiment, this invention is not limited to embodiment described in this specification. The scope of the present invention is determined by the description of the scope of claims and the scope equivalent to the description of the scope of claims. Hereinafter, modified embodiments in which the above-described embodiment is partially modified will be described.

  The shape, arrangement, numerical value, material, and the like of each member constituting the embodiment described above can be changed as appropriate. Moreover, you may combine embodiment mentioned above.

  In the above-described embodiment, the present invention is applied to the double-sided printing apparatus, but the present invention may be applied to a single-sided printing apparatus.

  In the above-described embodiment, the electromagnetic valve is applied as the switching unit. However, a switching unit capable of switching other routes may be applied.

  In the above-described embodiment, the present invention is applied to a single-color duplex printing apparatus. However, the present invention may be applied to a printing apparatus that prints multiple colors (for example, four colors). Here, when the present invention is applied to a printing apparatus capable of printing a plurality of colors, it is preferable to provide switching means such as an electromagnetic valve in the ink circulation path of each color. In this case, when switching the switching means based on the ink temperature, it may be configured to switch individually based on the ink temperature of each color, or may be configured to switch at the same time based on the average of the ink temperatures of all colors. Also good. Furthermore, a heat exchanger for averaging the ink temperature may be provided so as to cross each circulation path.

  In the embodiment described above, the threshold temperature is set to the appropriate center temperature, but the threshold temperature may be a temperature other than the appropriate center temperature. For example, by setting the threshold temperature lower than the appropriate central temperature, the ink circulates in the heating circulation path even if the ink temperature is lower than the appropriate central temperature. Thereby, since the ink is kept warm by the remaining heat for a longer time, it is possible to reduce the heating of the ink that requires a longer time at the start of printing.

  In the above-described embodiment, the ambient temperature sensor is attached to the inside of the housing, and the ambient temperature is set to the temperature inside the housing. However, the ambient temperature sensor is attached to the outside of the housing, and the ambient temperature is set to the vicinity of the outside of the housing. It is good also as temperature.

  In the above-described embodiment, the ink temperature sensor is provided inside the ink jet head, but the ink temperature sensor may be provided in another part of the circulation path.

  In 2nd Embodiment mentioned above, although it comprised so that a cooling fan might be stopped after the setting of a solenoid valve (switching means), you may comprise so that a heater may be set after the setting of a solenoid valve. Thereby, even when the ambient temperature is lower than the appropriate temperature range, it is possible to suppress the ink from being cooled by the ambient temperature. In other words, if the heater is stopped prior to the setting of the solenoid valve, ink cooling is started earlier due to the ambient temperature, but by delaying the heater stop, this cooling is delayed due to the residual heat of the heater. Can be suppressed. Furthermore, you may comprise so that a cooling fan and a heater may be stopped after the setting of a solenoid valve.

DESCRIPTION OF SYMBOLS 1 Duplex printing apparatus 3 Conveyance printing part 7 Ambient temperature sensor 8 Control part 9 Housing | casing 17 Printing part 18 Supply part 19 Circulation part 20 Inkjet head 22 Ink bottle 23 Supply pipe 25 Lower tank 26 Circulation pump 27 Electromagnetic valve 28 Heater 29 Cooling Container 29a Heat sink 29b Cooling fan 30 Upper tanks 31a to 31f Circulation pipe 31d ₁ Heating side upstream pipe part 31d ₂ Cooling side upstream pipe part 31d ₃ Merge pipe 32 Ink temperature sensor 50 Ink C1-C2 Heating circulation path C1-C3 Cooling circulation path Ta Ambient temperature Tu Appropriate temperature upper limit temperature Td Appropriate temperature lower limit temperature ThT Threshold temperature Ti Ink temperature ThM Threshold time

Claims (5)

A circulation unit having switching means for switching to either a heating circulation path for circulating ink while being heated by a heating means or a cooling circulation path for circulating ink while being cooled by a cooling means;
Ambient temperature measuring means for measuring and outputting the ambient temperature,
A printing apparatus comprising: a control unit configured to control the switching unit based on the ambient temperature input from the ambient temperature measurement unit and set an ink circulation path after completion of image printing. After the image printing is finished, the control unit
When the ambient temperature is equal to or lower than the optimum temperature lower limit temperature of the ink, the switching means is set to the heating circulation path side,
The printing apparatus according to claim 1, wherein when the ambient temperature is equal to or higher than an appropriate upper limit temperature of ink, the switching unit is set to a cooling circulation path side. An ink temperature measuring means for measuring and outputting the ink temperature;
After the image printing is finished, the control unit
When the ambient temperature is within the appropriate temperature range of the ink and the ink temperature input from the ink temperature measuring means is equal to or higher than the threshold temperature within the appropriate temperature range of the ink, the switching means is set to the cooling circulation path side. ,
When the ambient temperature is within the appropriate temperature range of the ink and the ink temperature input from the ink temperature measuring means is less than the threshold temperature within the appropriate temperature range of the ink, the switching means is set to the heating circulation path side. The printing apparatus according to claim 1, wherein the printing apparatus is a printer.   The printing apparatus according to claim 1, wherein the control unit stops the cooling unit or the heating unit after setting the switching unit.   The printing apparatus according to any one of claims 1 to 4, wherein a path length of the heating circulation path is shorter than a path length of the cooling circulation path.