Printing device

Abstract

To suppress sticking of a rear surface of a medium and a contact heating surface and increase in friction force.SOLUTION: A printing device 1 includes a transfer part 6, a printing part 3, a drying part 10, and a control part 7. The drying part 10 includes a contact heating part 131 and an air flow jetting part 12 for jetting an air flow from an air flow jetting port 121. The contact heating part 131 includes a contact heating surface 132 in contact with a rear surface P2 of a medium P. The air flow jetting port 121 faces the contact heating surface 132. The control part 7 can perform first control to control the air flow jetting part 12 so that the arrival speed of the air flow is a first speed and second control to control the air flow jetting part 12 so that the arrival speed of the air flow is slower than the first speed. During the operation of the printing device 1, the printing device is configured to perform the first control when stop time in which transfer of the medium P by the transfer part 6 is halted is less than a prescribed period of time and perform the second control instead of the first control when the stop time is the prescribed period of time or more.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a printing apparatus.

Background Art

[0002] Conventionally, various printing apparatuses have been used. Among these, in order to dry the liquid ejected onto the medium, in the drying unit, there is a printing apparatus including an air flow injection unit that blows an air flow onto the printing surface of the medium, and a contact heating surface that contacts the back surface of the medium opposite to the printing surface at a position facing the air flow injection unit. For example, Patent Document 1 discloses a printing apparatus having a first heater and a second heater that contact the back surface of the medium to heat the medium, and a first non-contact heating unit and a second non-contact heating unit that are arranged to face the first heater and the second heater and blow hot air onto the surface of the medium in the drying unit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a printing apparatus including an air flow injection unit and a contact heating surface provided at a position facing the air flow injection unit, the air flow ejected from the air flow injection unit presses the medium against the contact heating surface. Therefore, depending on the type of medium used, etc., the back surface of the medium and the contact heating surface may stick together, or the frictional force when transporting the medium may increase and the transport performance may decrease.

Means for Solving the Problems

[0005] The printing apparatus of the present invention for solving the above problems includes a conveyance unit that conveys a medium in a conveyance direction, a printing unit that discharges a liquid onto the medium conveyed by the conveyance unit to perform printing, a drying unit that dries the medium printed on a printing surface by the printing unit, and a control unit. The drying unit has a contact heating unit and an air flow injection unit that is disposed at a position facing the contact heating unit and injects an air flow from an air flow injection port. The contact heating unit has a contact heating surface that contacts a back surface, which is a surface opposite to the printing surface. The air flow injection port faces the contact heating surface. The control unit can execute a first control for controlling the air flow injection unit so that a reaching speed, which is a speed at which the air flow injected from the air flow injection unit reaches the printing surface of the medium supported by the contact heating surface, becomes a first speed, and a second control for controlling the air flow injection unit so that the reaching speed becomes slower than the first speed. When a stop time during which the conveyance of the medium by the conveyance unit stops during the operation of the printing apparatus is less than a predetermined time, the first control is performed. When the stop time is equal to or longer than the predetermined time, the second control can be performed instead of the first control.

Brief Description of the Drawings

[0006]

Figure 1

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Figure 10

Embodiments for Carrying Out the Invention

[0007] First, the present invention will be schematically described. A printing apparatus according to a first aspect of the present invention for solving the above problems includes a conveyance unit that conveys a medium in a conveyance direction, a printing unit that discharges a liquid onto the medium conveyed by the conveyance unit to perform printing, a drying unit that dries the medium having printing on a printing surface by the printing unit, and a control unit. The drying unit has a contact heating unit and an air flow injection unit that is disposed at a position facing the contact heating unit and injects an air flow from an air flow injection port. The contact heating unit has a contact heating surface that contacts a back surface, which is a surface opposite to the printing surface. The air flow injection port faces the contact heating surface. The control unit is capable of executing a first control for controlling the air flow injection unit so that a reaching speed, which is a speed at which the air flow injected from the air flow injection unit reaches the printing surface of the medium supported by the contact heating surface, becomes a first speed, and a second control for controlling the air flow injection unit so that the reaching speed becomes slower than the first speed. When a stop time during which conveyance of the medium by the conveyance unit stops during operation of the printing apparatus is less than a predetermined time, the first control is performed, and when the stop time is equal to or more than the predetermined time, the second control is performed instead of the first control.

[0008] According to this aspect, it is possible to execute a first control in which the arrival speed of the air flow to the printing surface is the first speed, and a second control in which the arrival speed of the air flow to the printing surface is slower than the first speed. When the stop time during the operation of the printing apparatus is less than a predetermined time, the first control is performed, and when the stop time is equal to or more than the predetermined time, it is configured to be possible to perform the second control instead of the first control. Therefore, when the stop time, which may cause the back surface of the medium and the contact heating surface to stick together or the frictional force when transporting the medium to increase and the transport performance to deteriorate, is equal to or more than the predetermined time, the arrival speed of the air flow to the printing surface can be slowed down. As a result, it is possible to suppress the sticking between the back surface of the medium and the contact heating surface and the increase in the frictional force.

[0009] The printing apparatus according to the second aspect of the present invention is an aspect subordinate to the first aspect, and the control unit is configured to be able to determine whether to perform the first control or the second control when the stop time is equal to or more than the predetermined time according to the material of the back surface.

[0010] Depending on the material of the back surface of the medium, it is likely that the back surface of the medium and the contact heating surface will stick together, or the frictional force when transporting the medium will increase and the transport performance will deteriorate. However, according to this aspect, it is configured to be possible to determine whether to perform the first control or the second control when the stop time is equal to or more than the predetermined time according to the material of the back surface of the medium. Therefore, regardless of the material of the back surface of the medium, it is possible to suppress the sticking between the back surface of the medium and the contact heating surface and the increase in the frictional force.

[0011] The printing apparatus according to the third aspect of the present invention is an aspect subordinate to the second aspect, and the control unit is configured to perform the second control when the material of the back surface contains polyethylene.

[0012] When the back surface material of the medium contains polyethylene, the back surface of the medium is likely to stick to the contact heating surface, and the frictional force when transporting the medium increases, resulting in a decrease in transport performance. However, according to this aspect, when the back surface material contains polyethylene, it is configured to perform the second control. Therefore, even when the back surface material of the medium contains polyethylene, it is possible to suppress the sticking between the back surface of the medium and the contact heating surface and the increase in frictional force.

[0013] The printing apparatus according to the fourth aspect of the present invention is an aspect subordinate to any one of the first to third aspects, wherein the control unit, as the second control, controls the air flow injection unit so that the arrival speed becomes a second speed slower than the first speed, and controls the air flow injection unit so that the arrival speed becomes a third speed faster than the second speed and slower than the first speed. It is characterized in that it is configured to be possible.

[0014] According to this aspect, as the second control, it is configured to be possible to control the air flow injection unit so that the arrival speed of the air flow to the printing surface becomes a second speed slower than the first speed, and to control the air flow injection unit so that the arrival speed of the air flow to the printing surface becomes a third speed faster than the second speed and slower than the first speed. Therefore, the arrival speed of the air flow to the printing surface can be changed in at least three or more stages, and preferably, it is possible to suppress the sticking between the back surface of the medium and the contact heating surface and the increase in frictional force.

[0015] The printing apparatus according to the fifth aspect of the present invention is an aspect subordinate to the fourth aspect, wherein the control unit is configured to be able to control the air flow injection unit so that it becomes the third speed after controlling the air flow injection unit so that it becomes the second speed as the second control, and further control the air flow injection unit so that it becomes the first speed as the first control. It is characterized by that.

[0016] According to this aspect, after controlling the airflow injection unit to reach the second speed, the airflow injection unit is controlled to reach the third speed, and further, the airflow injection unit is configured to be controllable to reach the first speed. By controlling in this way, it is possible to particularly preferably suppress the sticking between the back surface of the medium and the contact heating surface and the increase in frictional force.

[0017] The printing apparatus according to the sixth aspect of the present invention is an aspect subordinate to any one of the first to third aspects, wherein the conveying unit intermittently conveys the medium during the execution of printing on the medium by the printing unit, and the printing unit discharges the liquid onto the medium during the conveyance stop of the intermittent conveyance, and does not discharge the liquid onto the medium during the conveyance of the intermittent conveyance. The control unit is configured to be able to control the airflow injection unit so that the arrival speed becomes slower than the first speed during the conveyance of the medium in the intermittent conveyance.

[0018] According to this aspect, the airflow injection unit is configured to be controllable so that the arrival speed of the airflow to the printing surface becomes slower than the first speed during the conveyance of the medium in the intermittent conveyance. When the airflow during the conveyance of the medium in the intermittent conveyance is strong and presses the medium against the contact heating surface, an increase in frictional force is likely to occur, but such an increase in frictional force can be suppressed.

[0019] The printing apparatus according to the seventh aspect of the present invention is an aspect subordinate to any one of the first to third aspects, wherein the control unit is configured to be able to control the arrival speed by controlling the air volume of the airflow injection unit.

[0020] According to this aspect, by controlling the air volume of the airflow injection unit, the arrival speed of the airflow to the printing surface is configured to be controllable. With such a configuration, it is possible to preferably control the arrival speed of the airflow to the printing surface without increasing the number of components.

[0021] The printing apparatus according to the eighth aspect of the present invention is an aspect subordinate to any one of the first to third aspects, wherein the air flow injection unit includes a fan that generates the air flow, an air guiding unit that connects between the fan and the air flow injection port, and a valve provided in the air guiding unit and capable of controlling an opening / closing amount, and the control unit is configured to be able to control the arrival speed by controlling the opening / closing amount of the valve.

[0022] According to this aspect, it is configured to be able to control the arrival speed of the air flow to the printing surface by controlling the opening / closing amount of the valve. Therefore, by controlling the opening / closing amount of the valve, it is possible to suitably control the arrival speed of the air flow to the printing surface.

[0023] The printing apparatus according to the ninth aspect of the present invention is an aspect subordinate to any one of the first to third aspects, wherein the air flow injection unit has a distance changing unit capable of changing the distance between the contact heating surface and the air flow injection port, and the control unit is configured to be able to control the arrival speed by controlling the distance changing unit to change the distance.

[0024] According to this aspect, it is configured to be able to control the arrival speed of the air flow to the printing surface by changing the distance between the contact heating surface and the air flow injection port. Therefore, by changing the distance between the contact heating surface and the air flow injection port, it is possible to suitably control the arrival speed of the air flow to the printing surface.

[0025] The printing apparatus according to the tenth aspect of the present invention is an aspect subordinate to any one of the first to third aspects, wherein the control unit is configured to be able to adopt at least one of increasing the temperature of the contact heating surface, increasing the temperature of the air flow ejected from the air flow injection port, and increasing the staying time of the medium in the drying unit when performing the second control compared to when performing the first control.

[0026] According to this aspect, when performing the second control, at least one of the following can be adopted: increasing the temperature of the contact heating surface, increasing the temperature of the air flow ejected from the air flow ejection port, and increasing the time for which the medium stays in the drying unit, compared to when performing the first control. Therefore, by reducing the arrival speed of the air flow to the printing surface, the drying efficiency decreases compared to when performing the first control. However, by adopting at least one of increasing the temperature of the contact heating surface, increasing the temperature of the air flow ejected from the air flow ejection port, and increasing the time for which the medium stays in the drying unit, drying can be compensated for.

[0027] Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. First, an overview of a printing apparatus 1 as an example of an embodiment of the present invention will be described with reference to FIG. 1. As shown in FIG. 1, the printing apparatus 1 of this embodiment includes a setting unit 2 for setting a roll-shaped medium P, a winding unit 5 for winding the medium P conveyed from the setting unit 2, and a printing head 3 as a printing unit that discharges liquid ink onto a printing surface P1 of the medium P conveyed in a conveyance direction A in a conveyance path from the setting unit 2 to the winding unit 5 to form an image. Further, the printing apparatus 1 of this embodiment includes a platen 4 that supports the medium P in an image formation region where an image is formed by the printing head 3, and a plurality of rollers 6 provided in the conveyance path of the medium P. The printing apparatus 1 of this embodiment has, as the roller 6, a driving roller that applies a conveyance force to the medium P as a conveyance unit, and a driven roller that rotates passively as the medium P is conveyed. Further, the printing apparatus 1 of this embodiment includes a control unit 7 having a CPU 7a, a storage unit 7b, etc., and each component member of the printing apparatus 1 of this embodiment is driven under the control of the control unit 7. The control unit 7 can input information on the medium P to be used from an external computer or the like connected to the printing apparatus 1 of this embodiment.

[0028] The printing head 3 is provided on the side facing the printing surface P1 of the medium P conveyed in the conveyance direction A, and forms an image by discharging ink onto the printing surface P1 while the back surface P2 on the side opposite to the printing surface P1 of the medium P is supported by the platen 4. Specifically, the printing apparatus 1 of the present embodiment prints by reciprocating the printing head 3 in the scanning direction C along the conveyance direction A. More specifically, the printing apparatus 1 of the present embodiment intermittently drives (intermittently conveys) the medium P in the conveyance direction A, reciprocates the printing head 3 in the scanning direction C, and discharges ink from the printing head 3 to perform printing.

[0029] The printing head 3 of the present embodiment can complete the image formation of the entire image formation area supported by the platen 4 on the printing surface P1 in one scan (one pass), and can also complete the image formation by performing a plurality of scans (a plurality of passes) on the entire image formation area. Compared with the case where the image formation is completed in one pass, when the image formation is completed in a plurality of passes, the conveyance stop time of the medium P accompanying the intermittent conveyance naturally becomes longer.

[0030] The printing head 3 of the present embodiment is configured to print by reciprocating in the scanning direction C along the conveyance direction A. However, the configuration of the printing head 3 is not particularly limited. Instead of the printing head 3 that reciprocates in the scanning direction C along the conveyance direction A to perform printing, a printing head 3 that reciprocates in the width direction B intersecting the conveyance direction A to perform printing may be provided, or a so-called line head in which nozzles for discharging ink are arranged side by side along the width direction B over the entire width direction B of the medium P and printing is performed in a state where the printing head stops may be provided.

[0031] As shown in FIG. 1, in the conveyance path of the medium P, downstream of the print head 3 in the conveyance direction A, there is a drying unit 10 for drying the ink ejected onto the medium P. A plurality of driven rollers 6 are provided in the conveyance path of the medium P from the print head 3 to the drying unit 10 and in the conveyance path of the medium P from the drying unit 10 to the winding unit 5. The printing apparatus 1 of the present embodiment includes, as the drying unit 10, a first drying unit 10A where the medium P first arrives from the print head 3, and a second drying unit 10B capable of further drying the medium P after drying the medium P in the first drying unit 10A. As shown in FIG. 1, in the present embodiment, the first drying unit 10A and the second drying unit 10B are provided one above the other. However, the present invention is not limited to such a configuration.

[0032] Hereinafter, the drying unit 10 will be described in more detail with reference to FIGS. 2 and 3. As shown in FIG. 2, the drying unit 10 includes a plurality of fans 11. As described above, the drying unit 10 is divided into a first drying unit 10A and a second drying unit 10B. In the first drying unit 10A, the airflow generated by the fan 11 can be jetted from the first airflow jetting unit 12A on the lower surface side toward the printing surface P1 of the medium P. In the second drying unit 10B, the airflow generated by the fan 11 can be jetted from the second airflow jetting unit 12B on the upper surface side toward the printing surface P1 of the medium P. The first airflow jetting unit 12A and the second airflow jetting unit 12B have the same configuration, and the first airflow jetting unit 12A is shown in FIG. 3.

[0033] As shown in FIG. 3, in the first air flow injection part 12A, a plurality of air flow injection ports 121 (first air flow injection ports 121A) are arranged alternately in the width direction B and the conveyance direction A. As described above, since the first air flow injection part 12A and the second air flow injection part 12B as the air flow injection part 12 have the same configuration, the first air flow injection part 12A can be read as the second air flow injection part 12B, and the first air flow injection port 121A can be read as the second air flow injection port 121B. The first drying part 10A includes a first contact heating part 131A as a contact heating part 131 having a first contact heating surface 132A as a contact heating surface that contacts and heats the back surface P2 of the medium P in a region facing the first air flow injection part 12A in the conveyance path of the medium P. On the other hand, the second drying part 10B includes a second contact heating part 131B having a second contact heating surface 132B that contacts and heats the back surface P2 of the medium P in a region facing the second air flow injection part 12B in the conveyance path of the medium P. The second contact heating part 131B has the same configuration as the first contact heating part 131A. As the contact heating surface 132, for example, a configuration having a rubber heater or the like can be adopted.

[0034] Thus, the printing apparatus 1 of the present embodiment includes a roller 6 as a conveyance part that conveys the medium P in the conveyance direction A, a printing head 3 that discharges and prints ink on the medium P conveyed by the roller 6, and a drying part 10 that dries the medium P printed by the printing head 3. The drying part 10 is divided into a first drying part 10A and a second drying part 10B. The first drying part 10A includes a first contact heating part 131A and a first air flow injection part 12A arranged at a position facing the first contact heating part 131A. The second drying part 10B includes a second contact heating part 131B provided downstream of the first contact heating part 131A in the conveyance direction A and a second air flow injection part 12B arranged at a position facing the second contact heating part 131B.

[0035] The first contact heating part 131A has a first contact heating surface 132A that faces and contacts the back surface P2 of the medium P after printing. The second contact heating part 131B has a second contact heating surface 132B that faces and contacts the back surface P2 of the medium P after printing. The first air flow injection port 121A of the first air flow injection part 12A faces the first contact heating surface 132A. The second air flow injection port 121B of the second air flow injection part 12B faces the second contact heating surface 132B.

[0036] As shown in FIGS. 1 and 2, the roller 6 disposed between the first drying part 10A and the second drying part 10B in the conveyance path of the medium P folds back the conveyance path of the medium P. In other words, the roller 6 disposed between the first drying part 10A and the second drying part 10B is a folding part 61 that is downstream in the conveyance direction A from the first contact heating part 131A and upstream in the conveyance direction A from the second contact heating part 131B. The folding part 61 folds the medium P so that the back surface P2 that has contacted the first contact heating surface 132A contacts the second contact heating surface 132B.

[0037] As shown in FIG. 2, the space between the first contact heating surface 132A and the first air flow injection part 12A and the space between the second contact heating surface 132B and the second air flow injection part 12B constitute the conveyance path of the medium P. Although details will be described later, in the printing apparatus 1 of the present embodiment, the first interval G1, which is the distance between the first contact heating surface 132A and the first air flow injection port 121A, and the second interval G2, which is the distance between the second contact heating surface 132B and the second air flow injection port 121B, are configured to be adjustable. As described above, the drying part 10 of the present embodiment has a contact heating part 131 (the first contact heating part 131A and the second contact heating part 131B) and an air flow injection part 12 (the first air flow injection part 12A and the second air flow injection part 12B) that is disposed at a position facing the contact heating part 131 and injects an air flow from the air flow injection ports 121 (the first air flow injection port 121A and the second air flow injection port 121B). The contact heating part 131 has a contact heating surface 132 (the first contact heating surface 132A and the second contact heating surface 132B) that contacts the back surface P2, which is the surface opposite to the printing surface P1, and the air flow injection ports 121 face the contact heating surface 132.

[0038] Next, with reference to FIGS. 4 to 6, the flow of the air current in the drying section 10 will be described. The flow of the air current is represented by an arrow F in FIG. 4. The drying section 10 is provided with an intake section 142 in which an intake fan 141, which is a DC fan, is provided. The intake section 142 is connected to a circulation mixing section 143 provided with valves 144 (first valve 144A and second valve 144B), and the air current sucked from the intake fan 141 flows from the intake section 142 to the circulation mixing section 143 as represented by the arrow F.

[0039] The circulation mixing section 143 is connected to first and second pressure chambers 145A and 145B which are two pressure chambers 145, and the air current flows from the circulation mixing section 143 to the first and second pressure chambers 145A and 145B as represented by the arrow F. The pressure chamber 145 is a unit for uniformly applying the air current to a heater section 146 described later. The first pressure chamber 145A is connected to a first heater section 146A as the heater section 146, and the air current flows from the first pressure chamber 145A to the first heater section 146A as represented by the arrow F. On the other hand, the second pressure chamber 145B is connected to a second heater section 146B as the heater section 146, and the air current flows from the second pressure chamber 145B to the second heater section 146B as represented by the arrow F. The heater section 146 of the present embodiment has a configuration having a cartridge heater with a length of 1500 mm and capable of heating the air current to 75°C.

[0040] The first heater section 146A is connected to a first nozzle box 147A as a nozzle box 147 provided in the first air current injection section 12A, and the air current flows from the first heater section 146A to the first nozzle box 147A as represented by the arrow F. The nozzle box 147 is a unit for spraying the heated air current onto the medium P. On the other hand, the second heater section 146B is connected to a second nozzle box 147B as a nozzle box 147 provided in the second air current injection section 12B, and the air current flows from the second heater section 146B to the second nozzle box 147B as represented by the arrow F.

[0041] The first nozzle box 147A is provided with a first air flow injection surface 120A having a first air flow injection port 121 as the air flow injection surface 120. Through the first air flow injection port 121, the air flow flows to the fan forming portion 148 provided with the fan 11 as represented by the arrow F. On the other hand, the second nozzle box 147B is provided with a second air flow injection surface 120B having a second air flow injection port 121B. Through the second air flow injection port 121B, the air flow flows to the fan forming portion 148 provided with the fan 11 as represented by the arrow F. Here, the fan 11 is a DC fan and is a component for discharging the heated air flow from inside the drying unit 10.

[0042] The fan forming portion 148 is connected to a discharge passage 149 connected to the exhaust duct 150, and the air flow is sent from the fan forming portion 148 to the exhaust duct 150 through the discharge passage 149 as represented by the arrow F. That is, the air flow circulated inside the drying unit 10 is discharged from the exhaust duct 150 to the outside of the printing apparatus 1. Here, the fan forming portion 148 is also connected to the circulation mixing portion 143 through the discharge passage 149, collects the heated air flow, mixes it with the outside air, and sends the heated air flow to the pressure chamber 145 by the blower 151. As shown in FIGS. 5 and 6, the blowers 151 (the first blower 151A and the second blower 151B) facilitate the flow of the air flow inside the drying unit 10 together with the intake fan 141 and the fan 11.

[0043] The printing apparatus 1 of the present embodiment can control the air flow under the control of the control unit 7. Hereinafter, the control of the air flow by the control unit 7 will be described. The control unit 7 performs a first control for controlling the air flow injection unit 12 so that the arrival speed, which is the speed at which the air flow injected from the air flow injection unit 12 reaches the printing surface P1 of the medium P supported by the contact heating surface 132, becomes a first speed, and a second control for controlling the air flow injection unit 12 so that the arrival speed of the air flow at the printing surface P1 is slower than the first speed. Specifically, when the stop time during which the conveyance of the medium P by the roller 6 as the conveyance unit stops during the operation of the printing apparatus 1 is less than a predetermined time, the control unit 7 performs the first control, and when the stop time is equal to or longer than the predetermined time, the control unit 7 can perform the second control instead of the first control.

[0044] Therefore, when the stop time during which the back surface P2 of the medium P may stick to the contact heating surface 132 or the frictional force when transporting the medium P may increase and the transport performance may deteriorate is equal to or longer than a predetermined time, the printing apparatus 1 according to the present embodiment can slow down the arrival speed of the airflow to the printing surface P1. As a result, the printing apparatus 1 according to the present embodiment can suppress the sticking between the back surface P2 of the medium P and the contact heating surface 132 and the increase in the frictional force.

[0045] Specifically, the control unit 7 can perform control of the airflow and the like according to the tables represented by Tables 1 to 3 below. First, the control of the airflow according to the table represented by Table 1 will be described. In the control of the airflow according to the table represented by Table 1, different controls are performed according to four cases: whether the medium P is being transported or has stopped for a predetermined time or more during the intermittent transport during the execution of the printing operation, and whether the medium P is being transported or has stopped for a predetermined time or more when the printing operation is not being executed.

[0046] [Table 1]

[0047] In the control of the airflow according to the table represented by Table 1, the purpose of the control of the airflow during the transport of the medium P during the intermittent transport during the execution of the printing operation is to reduce the transport load that may occur when the medium P is strongly pressed against the contact heating surface by the airflow with a high wind speed. In this control, the wind speed, which is the arrival speed of the airflow to the printing surface P1, is set to a weak wind speed that is slower than the strong wind speed of the first speed. However, since the drying property of the medium P decreases as the wind speed becomes the weak wind speed, drying compensation is performed. Specific examples of the drying compensation include an increase in the temperature of the contact heating surface 132, an increase in the temperature of the heater unit 146 that warms the airflow, and an extension of the residence time of the medium P in the drying unit 10.

[0048] During the stop of the medium P in the intermittent conveyance during the printing operation, that is, when ink is being ejected from the print head 3 onto the printing surface P1 of the medium P, the purpose of airflow control is to prioritize the drying of the medium P. Note that during the stop of the medium P in the intermittent conveyance during the printing operation, the stop time is within 1 minute. In this control, the wind speed, which is the arrival speed of the airflow at the printing surface P1, is set to a strong wind speed, which is the case of the first speed. In this control, since the wind speed is strong, drying compensation is not performed.

[0049] For example, during maintenance operations, when the medium P is stopped instead of during the printing operation, the purpose of airflow control is to prevent the medium P from sticking to the contact heating surface. In this control, the wind speed, which is the arrival speed of the airflow at the printing surface P1, is set to a weak wind speed, which is slower than the strong wind speed in the case of the first speed. In this control, since it is not during the printing operation, drying compensation is not performed.

[0050] For example, when an operator is rewinding the medium P, when the medium P is being conveyed instead of during the printing operation, the purpose of airflow control is to maintain the temperature inside the drying unit 10. If the wind speed is reduced, the temperature inside the drying unit 10 is likely to decrease. Therefore, in this control, the wind speed, which is the arrival speed of the airflow at the printing surface P1, is set to a strong wind speed, which is the case of the first speed. In this control, since it is not during the printing operation, drying compensation is not performed.

[0051] Next, the airflow control according to the table shown in Table 2 will be described. In the airflow control according to the table shown in Table 2, in addition to whether the medium P is being conveyed or stopped for a predetermined time or more during the intermittent conveyance during the printing operation, and whether the medium P is being conveyed or stopped for a predetermined time or more when the printing operation is not being performed, different controls are performed according to the type of the medium P during the stop of the conveyance, and different controls are made in a total of six cases.

[0052]

Table 2

[0053] In the control of the air flow according to the table represented by Table 2, the control during the conveyance of the medium P in the intermittent conveyance during the execution of the printing operation and the control of the air flow when the medium P is being conveyed but not during the execution of the printing operation are the same as those in the case of the table represented by Table 1. On the other hand, the control during the stop of the medium P in the intermittent conveyance during the execution of the printing operation and the control of the air flow when the medium P is stopped but not during the execution of the printing operation differ depending on the type of material used for the back surface P2 of the medium P to be used. Specifically, only when polyethylene (PE) is used for the back surface P2 of the medium P to be used, the control is different from that in the case of the table represented by Table 1. Polyethylene has the property of being easily attached to the contact heating surface.

[0054] When polyethylene is used for the back surface P2 of the medium P to be used, the purpose of the control of the air flow during the stop of the medium P in the intermittent conveyance during the execution of the printing operation is to prevent the medium P from sticking. For example, when restarting printing after maintenance corresponding to outside the execution of the printing operation, the wind speed is set to weak wind speed except during the execution of the printing operation when the medium P is stopped as described later, so the temperature inside the drying unit 10 may drop. When the temperature inside the drying unit 10 drops, the drying efficiency decreases. Therefore, in order to compensate for this, the drying time may be lengthened, that is, the stop time may be lengthened. When the stop time is lengthened, the medium P is likely to stick to the contact heating surface 132. Here, when the wind speed, which is the arrival speed of the air flow to the printing surface P1 after restarting printing, is set to strong wind speed, which is the first speed, for example, the medium P may stick to the contact heating surface 132 because the not sufficiently heated air flow blows strongly on the medium P. This is a control to set the wind speed to weak wind speed to reduce such a risk. In this control, since the wind speed is weak wind speed, drying compensation is performed.

[0055] When polyethylene is used for the back surface P2 of the medium P to be used, the purpose of the control of the air flow when the medium P is stopped but not during the execution of the printing operation is also to prevent the medium P from sticking. Specifically, the wind speed is set to weak wind speed. In this control, since it is not during the execution of the printing operation, drying compensation is not performed.

[0056] Next, the control of the air flow according to the table shown in Table 3 will be described. In the control of the air flow according to the table shown in Table 3, similar to the control of the air flow according to the table shown in Table 2, during the intermittent conveyance during the execution of the printing operation, whether the medium P is being conveyed or stopped for a predetermined time or more, and during the non-execution of the printing operation, whether the medium P is being conveyed or stopped for a predetermined time or more. In addition, during the stop of the conveyance, different controls are performed according to the type of the medium P, and different controls are made in a total of six cases. The difference between the control of the air flow according to the table shown in Table 3 and the control of the air flow according to the table shown in Table 2 is only the control of the air flow during the stop of the medium P during the intermittent conveyance during the execution of the printing operation when polyethylene is used for the back surface P2 of the medium P to be used.

[0057]

Table 3

[0058] In the case where polyethylene is used for the back surface P2 of the medium P to be used, in the control of the air flow during the stop of the medium P during the intermittent conveyance during the execution of the printing operation, the wind speed is changed in order from weak wind speed, medium wind speed, and strong wind speed. The period during which the wind speed is weak is, for example, the period until the temperature in the drying unit 10 recovers. And the drying completion is only when the wind speed is weak. By performing such control, it is also possible to prevent the sticking of the medium P.

[0059] Here, with reference to FIG. 7, the control of the air flow according to the table shown in Table 3 will be described in more detail. FIG. 7 shows the strength of the wind speed corresponding to the conveyance state of the medium P when polyethylene is used and when it is not used for the back surface P2 of the medium P to be used.

[0060] When polyethylene is used on the back surface P2 of the medium P to be used, the wind speed is increased to the strong wind speed upon power-on and printing is performed in that state. During intermittent conveyance, the wind speed is set to the weak wind speed, and when the intermittent conveyance corresponding to the execution of the printing operation stops, the wind speed is set to the strong wind speed. This corresponds to the case where polyethylene is used on the back surface P2 of the medium P to be used in Table 3, and to the control of the air flow during and when the medium P stops during intermittent conveyance during the execution of the printing operation in the period before the interruption of printing.

[0061] After the interruption of the printing operation, after stopping the conveyance of the medium P, a maintenance operation is performed. During the execution of the maintenance operation, the conveyance is stopped, but at this time, it corresponds to the case where the medium P stops during intermittent conveyance other than during the execution of the printing operation in Table 3, and the wind speed is set to the weak wind speed. When printing is resumed after the maintenance operation, during the stop of the conveyance of the medium P, the printing operation is performed while changing the wind speed in order from the weak wind speed, medium wind speed, and strong wind speed. At this time, it corresponds to the case where the medium P stops during intermittent conveyance during the execution of the printing operation in Table 3. In the example of FIG. 7, the wind speed is changed in order from the weak wind speed, medium wind speed, and strong wind speed for every two cycles of printing corresponding to the printing of two label sheets as an example of the medium P, but it is not limited to such an example. On the other hand, when polyethylene is not used on the back surface P2 of the medium P to be used, when printing is resumed after the maintenance operation, during the stop of the conveyance of the medium P, printing is performed with the wind speed set to the strong wind speed from the beginning. Note that one label sheet is a unit representing a plurality of labels printed by the print head 3 in the area of the medium P supported by the platen 4 during one stop of intermittent conveyance corresponding to the execution of the printing operation.

[0062] As described above, when the stop time corresponding to the case where intermittent conveyance is stopped is equal to or longer than a predetermined time according to the material of the back surface P2, the control unit 7 of the printing apparatus 1 of the present embodiment is configured to be able to determine whether to perform the first control in which the wind speed is set to a strong wind speed or the second control in which the wind speed is set to a medium wind speed or a weak wind speed. Depending on the material of the back surface P2 of the medium P, the back surface P2 of the medium P and the contact heating surface 132 may stick together, or the frictional force when conveying the medium P may increase and the conveying performance may decrease. However, since the printing apparatus 1 of the present embodiment is configured to be able to determine whether to perform the first control or the second control when the stop time is equal to or longer than a predetermined time according to the material of the back surface P2 of the medium P, it is possible to suppress the sticking between the back surface P2 of the medium P and the contact heating surface 132 and the increase in the frictional force according to the material of the back surface P2 of the medium P.

[0063] Specifically, when the material of the back surface P2 contains polyethylene, the control unit 7 is configured to perform the second control. When the material of the back surface P2 of the medium P contains polyethylene, particularly on the contact surface with the contact heating surface 132 of the back surface P2, the back surface P2 of the medium P and the contact heating surface 132 are likely to stick together, or the frictional force when conveying the medium P increases and the conveying performance decreases. However, since it is configured to perform the second control when the material of the back surface P2 contains polyethylene, even when the material of the back surface P2 of the medium P contains polyethylene, it is possible to suppress the sticking between the back surface P2 of the medium P and the contact heating surface 132 and the increase in the frictional force.

[0064] Further, as shown in FIG. 7, as a second control, the control unit 7 controls the air flow injection unit 12 so that the arrival speed of the air flow at the printing surface P1 is a weak wind speed which is a second speed slower than the strong wind speed which is the first speed, and controls the air flow injection unit 12 so that the arrival speed of the air flow at the printing surface P1 is a medium wind speed which is a third speed faster than the weak wind speed which is the second speed and slower than the strong wind speed which is the first speed. Therefore, the printing apparatus 1 of the present embodiment can change the arrival speed of the air flow at the printing surface P1 in three steps, and preferably can suppress the sticking between the back surface P2 of the medium P and the contact heating surface 132 and the increase in the frictional force. Note that the printing apparatus 1 of the present embodiment is configured to be able to change the arrival speed of the air flow at the printing surface P1 in three steps, but may be configured to be able to change the arrival speed of the air flow at the printing surface P1 in four or more steps.

[0065] Furthermore, as shown in FIG. 7, as a second control, the control unit 7 controls the air flow injection unit 12 so that the air flow becomes a weak wind speed which is a second speed, and then controls the air flow injection unit 12 so that the air flow becomes a medium wind speed which is a third speed, and further, as a first control, is configured to be able to control the air flow injection unit so that the air flow becomes a strong wind speed which is a first speed. By controlling in this way, it is possible to particularly preferably suppress the sticking between the back surface P2 of the medium P and the contact heating surface 132 and the increase in the frictional force.

[0066] In the printing apparatus 1 of the present embodiment, the roller 6 as the conveyance unit intermittently conveys the medium P during the execution of printing on the medium P by the print head 3, the print head 3 discharges ink onto the medium P during the conveyance stop of the intermittent conveyance, and does not discharge ink onto the medium P during the conveyance of the intermittent conveyance. The control unit 7 is configured to be able to control the air flow injection unit 12 so that the arrival speed of the air flow at the printing surface P1 is a weak wind speed slower than the strong wind speed which is the first speed during the conveyance of the medium P in the intermittent conveyance. If the air flow during the conveyance of the medium P in the intermittent conveyance is strong and presses the medium P against the contact heating surface 132, an increase in the frictional force is likely to occur, but such an increase in the frictional force can be suppressed.

[0067] Also, as described above, the printing apparatus 1 of this embodiment can perform drying supplementation. In other words, when the control unit 7 is performing the second control, it is configured to be able to adopt at least one of increasing the temperature of the contact heating surface 132, increasing the temperature of the air flow ejected from the air flow ejection port 121, and increasing the time that the medium P stays in the drying unit 10 compared to when performing the first control. Therefore, the printing apparatus 1 of this embodiment can reduce the drying efficiency by reducing the arrival speed of the air flow to the printing surface P1 compared to when performing the first control, and can perform drying supplementation by adopting at least one of increasing the temperature of the contact heating surface 132, increasing the temperature of the air flow ejected from the air flow ejection port 121, and increasing the time that the medium P stays in the drying unit 10.

[0068] The printing apparatus 1 of this embodiment is configured to be able to control the air volume of the air flow ejection unit 12 by controlling the driving of a plurality of fans such as the intake fan 141 under the control of the control unit 7, and thereby control the arrival speed of the air flow to the printing surface P1. By adopting such a configuration, it is possible to suitably control the arrival speed of the air flow to the printing surface P1 without increasing the number of components.

[0069] Also, in the printing apparatus 1 of this embodiment, the air flow ejection unit 12 includes an intake fan 141 that generates an air flow, a circulation mixing unit 143 as a wind guiding unit that connects between the intake fan 141 and the air flow ejection port, and a valve 144 provided in the circulation mixing unit 143 and capable of controlling the opening and closing amount. The control unit 7 is configured to be able to control the arrival speed of the air flow to the printing surface P1 by controlling the opening and closing amount of the valve 144. Therefore, the printing apparatus 1 of this embodiment can suitably control the arrival speed of the air flow to the printing surface P1 by controlling the opening and closing amount of the valve 144.

[0070] Furthermore, in the printing apparatus 1 of the present embodiment, the air flow injection unit 12 is configured to be able to change the distance between the contact heating surface 132 and the air flow injection port 121. The control unit 7 is configured to be able to control the arrival speed of the air flow to the printing surface P1 by controlling the distance changing unit 21 represented in FIG. 2 to change the first interval G1 and the second interval G2 which are the distances. Therefore, the printing apparatus 1 of the present embodiment can suitably control the arrival speed of the air flow to the printing surface P1 by changing the distance between the contact heating surface 132 and the air flow injection port 121. Hereinafter, the configuration will be described with reference to FIGS. 8 to 10.

[0071] As shown in FIG. 2, the printing apparatus 1 of the present embodiment includes a distance changing unit 21A, a distance changing unit 21B, a distance changing unit 21C, and a distance changing unit 21D as the distance changing unit 21. As shown in FIG. 8, the distance changing unit 21 includes a cam follower 201, a frame 200 with which the cam follower 201 engages and on which a movement path 200A of the cam follower 201 is provided, and a fixture 202 that is attached to the first contact heating unit 131 and to which the cam follower 201 (cam follower 201A) is attached.

[0072] As shown in FIGS. 8 and 10, the fixture 202 includes a motor 208, a motor fixing unit 209, a cam mechanism including a cam follower 201 (cam follower 201B) and a cam 207, a moving unit 203 on which the cam follower 201 is provided, a moving axis 205 of the moving unit 203, a linear bush 204 attached to the moving axis 205, and a holder 206 provided on the first contact heating unit 131A for fixing the moving axis 205.

[0073] The printing apparatus 1 of this embodiment drives the motor 208, and as shown in FIG. 9, rotates the cam 207 in the rotation direction R1 with respect to the motor shaft 208A of the motor 208 to displace the cam mechanism, thereby displacing the position of the first contact heating part 131A in the vertical direction with respect to the frame 200 and enabling adjustment of the first interval G1. As shown in FIG. 9, the cam 207 is provided with a movement path 207A of a rectangular cam follower 201 with a center position offset from the motor shaft 208A. By driving the motor 208, the position of the movement path 207A with respect to the cam follower 201 can be changed, and thereby the positions of the motor shaft 208A, the motor fixing part 209 to which the motor 208 is fixed, and the first contact heating part 131 to which the motor fixing part 209 is fixed are displaced in the vertical direction.

[0074] Note that the printing apparatus 1 of this embodiment includes distance changing parts 21C and 21D having the same configuration as the distance changing parts 21A and 21B, and is also configured to be able to adjust the second interval G2. With such a configuration of the printing apparatus 1 of this embodiment, the first interval G1 and the second interval G2 can be easily adjusted.

[0075] The present invention is not limited to the above-described embodiments, and can be realized in various configurations without departing from the gist thereof. For example, the technical features in the embodiments corresponding to the technical features in each form described in the summary of the invention can be appropriately replaced or combined in order to solve part or all of the above-described problems, or to achieve part or all of the above-described effects. Further, if the technical feature is not described as essential in this specification, it can be appropriately deleted.

Explanation of Reference Numerals

[0076] 1... Printing device, 2... Setting unit, 3... Print head (printing unit), 4... Platen, 5... Take-up unit, 6... Roller (conveying unit), 7... Control unit, 7a... CPU, 7b... Memory unit, 10... Drying unit, 10A... First drying unit, 10B... Second drying unit, 11... Fan, 12... Airflow injection unit, 12A... First airflow injection unit, 12B... Second airflow injection unit, 21... Distance changing unit, 21A... Distance changing unit, 21B... Distance changing unit, 21C... Distance changing unit, 21D... Distance changing unit, 61... Folding unit, 120... Airflow injection surface, 120A... First airflow injection surface, 120B... Second airflow injection surface, 121... Airflow injection port, 121A... First airflow injection port, 121B... Second airflow injection port, 131... Contact heating unit, 131A... First contact heating unit, 131B... Second contact heating unit, 132... Contact heating surface, 132A... First contact heating surface, 132B... Second contact heating surface, 141... Intake fan, 142... Intake part, 143... Circulation mixing unit (air guiding unit), 144... Valve, 144A... First valve, 144B... Second valve, 145... Pressure chamber, 145A... First pressure chamber, 145B... Second pressure chamber, 146... Heater unit, 146A... First heater unit, 146B... Second heater unit, 147... Nozzle box, 147A... First nozzle box, 147B... Second nozzle box, 148... Fan forming part, 149... Exhaust passage, 150... Exhaust duct, 151... Blower, 151A... First blower, 151B... Second blower, 200... Frame, 200A... Movement path, 201... Cam follower, 201A... Cam follower, 201B... Cam follower, 202... Fixture, 203... Moving part, 204... Linear bush, 205... Moving shaft, 206... Holder, 207... Cam, 207A... Movement path, 208... Motor, 208A... Motor shaft, 209... Motor fixing part, G1... First interval, G2... Second interval, P... Medium, P1... Printing surface, P2... Back surface

Claims

1. A conveying unit that conveys a medium in a conveying direction, A printing unit that discharges and prints a liquid onto the medium conveyed by the conveying unit, A drying unit that dries the medium printed on a printing surface by the printing unit, A control unit, A printing apparatus comprising: The drying unit has a contact heating unit and an air flow injection unit that is disposed at a position facing the contact heating unit and injects an air flow from an air flow injection port. The contact heating unit has a contact heating surface that contacts a back surface, which is a surface opposite to the printing surface. The air flow injection port faces the contact heating surface. The control unit: A first control for controlling the air flow injection unit so that a reaching speed, which is a speed at which the air flow injected from the air flow injection unit reaches the printing surface of the medium supported by the contact heating surface, becomes a first speed; and a second control for controlling the air flow injection unit so that the reaching speed becomes slower than the first speed. The control unit is capable of executing these controls. When a stop time during which the conveyance of the medium by the conveying unit stops during operation of the printing apparatus is less than a predetermined time, the first control is performed. When the stop time is equal to or longer than the predetermined time, the second control is performed instead of the first control. A printing apparatus characterized by being configured in this way.

2. In the printing apparatus according to Claim 1, The control unit is configured to be able to determine whether to perform the first control or the second control when the stop time is equal to or longer than the predetermined time according to the material of the back surface. A printing apparatus characterized by this.

3. In the printing apparatus according to Claim 2, When the back surface contains polyethylene as a material, the control unit is configured to perform the second control. A printing apparatus characterized by this.

4. In the printing apparatus according to any one of Claims 1 to 3, As the second control, the control unit is configured to be able to control the air flow injection unit so that the reaching speed becomes a second speed slower than the first speed, and to control the air flow injection unit so that the reaching speed becomes a third speed faster than the second speed and slower than the first speed. A printing apparatus characterized by this.

5. In the printing apparatus according to Claim 4, The control unit is configured to be capable of controlling the air flow injection unit to reach the second speed as the second control, then controlling the air flow injection unit to reach the third speed, and further controlling the air flow injection unit to reach the first speed as the first control. A printing apparatus characterized by this.

6. In the printing apparatus according to any one of claims 1 to 3, the conveying unit intermittently conveys the medium during execution of printing on the medium by the printing unit, the printing unit discharges the liquid onto the medium during the conveyance stop of the intermittent conveyance, and does not discharge the liquid onto the medium during the conveyance of the intermittent conveyance, the control unit is configured to be capable of controlling the air flow injection unit so that the reaching speed becomes slower than the first speed during the conveyance of the medium in the intermittent conveyance. A printing apparatus characterized by this.

7. In the printing apparatus according to any one of claims 1 to 3, the control unit is configured to be capable of controlling the reaching speed by controlling the air volume of the air flow injection unit. A printing apparatus characterized by this.

8. In the printing apparatus according to any one of claims 1 to 3, the air flow injection unit includes a fan that generates the air flow, a wind guiding unit that connects between the fan and the air flow injection port, and a valve provided in the wind guiding unit and capable of controlling the opening / closing amount, the control unit is configured to be capable of controlling the reaching speed by controlling the opening / closing amount of the valve. A printing apparatus characterized by this.

9. In the printing apparatus according to any one of claims 1 to 3, the air flow injection unit has a distance changing unit capable of changing the distance between the contact heating surface and the air flow injection port, the control unit is configured to be capable of controlling the reaching speed by controlling the distance changing unit to change the distance. A printing apparatus characterized by this.

10. In the printing apparatus according to any one of claims 1 to 3, when the control unit performs the second control, it can adopt at least one of raising the temperature of the contact heating surface, raising the temperature of the air flow ejected from the air flow injection port, and increasing the time the medium stays in the drying unit compared to when performing the first control. A printing apparatus characterized by this.

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