Printing apparatus

Abstract

The printing medium is heated efficiently while suppressing an increase in the driving power of the heating element. [Solution] A printing apparatus 1 comprising a transport unit 6 for transporting a printing medium P, a print head 3 for printing on the printing medium P, and a drying unit 10 located downstream of the print head 3 in the transport direction A, wherein the drying unit 10 comprises a plurality of support units 11 arranged in a line with gaps G along the transport direction A, and a heating unit 12 provided on each of the plurality of support units 11 for heating the support units 11, and each of the heating units 12 is capable of individually controlling its heating temperature.

Description

Technical Field

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

Background Art

[0002] Conventionally, various printing apparatuses that discharge ink onto a printing medium for printing have been used. Among these, there is a printing apparatus that includes a heating unit for heating the printing medium and can dry the ink discharged onto the printing medium. For example, Patent Document 1 discloses a printing apparatus having heating means that contacts the side opposite to the image forming surface of the printing 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] Patent Document 1 describes that in the drying unit, the upstream side in the conveyance direction (the drying unit inlet side) is set to a higher temperature than the downstream side in the conveyance direction (the drying unit outlet side). In such a configuration, when intermittently conveying the printing medium, there is an effect of making the temperature distribution of the printing medium uniform when the printing medium stops in the drying unit and preventing uneven drying. On the other hand, when continuously conveying the printing medium, the heating means on the drying unit inlet side, which is kept at a high temperature, is deprived of a large amount of heat by the printing medium at the same temperature as the ambient temperature coming into contact with it, so the amount of heat required from the heat source increases, and a large amount of electric power is required.

[0005] Furthermore, in the configuration of Patent Document 1, since the heating means that comes into contact with the printing medium is integrated in the direction of transport of the printing medium, the temperature of the heating means downstream will also decrease due to the temperature drop on the drying section inlet side, which may lead to an increase in load and power requirements not only on the drying section inlet side but also on the heat source downstream. Moreover, by raising the temperature on the drying section inlet side, the drying of the ink surface on the printing medium will proceed rapidly near the drying section inlet, forming a film on the surface, which may hinder the movement of moisture and solvent from inside the liquid droplets and actually hinder drying, so it may not be possible to say that the printing medium is heated efficiently. [Means for solving the problem]

[0006] The present invention, for solving the above problems, comprises a transport unit for transporting a printing medium in a transport direction, a print head for printing on the printing medium along the transport path of the printing medium, and a drying unit disposed downstream of the print head in the transport direction, wherein the drying unit has a plurality of support units arranged in a row with gaps along the transport direction for supporting the printing medium, and a heating unit provided on each of the plurality of support units for heating the support units, and each of the heating units is capable of individually controlling its heating temperature. [Brief explanation of the drawing]

[0007] [Figure 1] A schematic side view of the printing apparatus according to Embodiment 1 of the present invention. [Figure 2] Schematic plan view of the heating section of the printing apparatus shown in Figure 1. [Figure 3] Schematic side view of the heating section of the printing apparatus shown in Figure 1. [Figure 4] A block diagram illustrating the control configuration of the heating section of the printing apparatus shown in Figure 1. [Figure 5] A schematic plan view of the heating section of the printing apparatus according to Embodiment 2 of the present invention. [Figure 6] Figure 5 is a schematic side view of the heating section of the printing apparatus. [Figure 7] A schematic plan view of the heating section of the printing apparatus according to Embodiment 3 of the present invention. [Figure 8] A schematic plan view of the heating section of a reference printing apparatus. [Modes for carrying out the invention]

[0008] First, the present invention will be described in general terms. A printing apparatus according to a first aspect of the present invention for solving the above problems comprises a transport unit for transporting a printing medium in a transport direction, a print head for printing on the printing medium on the transport path of the printing medium, and a drying unit disposed downstream of the print head in the transport direction, wherein the drying unit has a plurality of support units arranged in a row with gaps along the transport direction for supporting the printing medium, and a heating unit provided on each of the plurality of support units for heating the support units, and each of the heating units is capable of individually controlling its heating temperature.

[0009] According to this embodiment, the apparatus includes a drying section, which is arranged in a row with gaps along the transport direction and has a plurality of support sections for supporting the printing medium, and a heating section provided on each of the plurality of support sections for heating the support sections, and the heating temperature of each heating section can be controlled individually. With this configuration, it is possible to set each heating section to a desired heating temperature while suppressing the escape of heat from the heating section to adjacent support sections. Therefore, the printing medium can be heated efficiently while suppressing an increase in the driving power of the heating section.

[0010] A printing apparatus according to a second aspect of the present invention, in an aspect dependent on the first aspect, has a control unit capable of controlling the transport unit and the heating unit, wherein the plurality of support units include a first support unit arranged in the transport path and a second support unit arranged downstream of the first support unit in the transport direction in the transport path, the heating unit includes a first heating unit for heating the first support unit and a second heating unit for heating the second support unit, and the control unit controls the transport unit so that the transport unit transports the printing medium continuously and controls the heating unit so that the heating temperature of the first heating unit is lower than the heating temperature of the second heating unit.

[0011] According to this embodiment, when transporting printing media continuously, the heating temperature of the first heating section upstream in the transport direction is set lower than the heating temperature of the second heating section downstream in the transport direction. With this configuration, for example, even if a large amount of heat is absorbed by the printing media when it comes into contact with the printing media at the same temperature as the ambient temperature near the entrance of the drying section, the heating temperature of the first heating section is set low, so the amount of heat required for the heating section to raise the temperature of the first heating section to the target temperature can be suppressed, and the need for large amounts of power can be suppressed.

[0012] A printing apparatus according to a third aspect of the present invention, in an embodiment dependent on the first or second aspect, is characterized in that the drying section includes an air supply section that blows air from an air supply section onto the printed surface of the printing medium printed by the print head, and a suction section in which a suction port is located downstream of the air supply section in the transport direction in the transport path.

[0013] According to this embodiment, the drying unit includes an air blowing unit that blows air from an air outlet onto the printed surface of the printing medium printed by the print head, and a suction unit in which a suction port is located downstream of the air outlet in the transport direction in the transport path. With this configuration, the printing medium can be dried not only by the heat of the heating unit but also by the airflow, enabling efficient drying of the printing medium.

[0014] A printing apparatus according to a fourth aspect of the present invention is characterized in that, in an embodiment dependent on the third aspect, the air outlet and the suction port are arranged to be wider than the width of the printing medium in the width direction intersecting the transport direction.

[0015] In this embodiment, the air outlet and suction port are arranged to be wider than the width of the printing medium in the width direction. With this configuration, air can be efficiently supplied to the printing medium, and the printing medium can be dried particularly efficiently.

[0016] The printing apparatus according to the fifth aspect of the present invention is, in an aspect subordinate to the fourth aspect, characterized in that the air blowing unit has an air flow heating unit that heats the air flow blown onto the printing surface, and blows the heated air flow from the air outlet.

[0017] According to this aspect, the air blowing unit has an air flow heating unit that heats the air flow blown onto the printing surface, and blows the heated air flow from the air outlet. With such a configuration, the heated gas can be blown onto the printing medium, and the printing medium can be dried particularly efficiently.

[0018] The printing apparatus according to the sixth aspect of the present invention is, in an aspect subordinate to any one of the first to fifth aspects, characterized in that the heating unit is a polyimide heater.

[0019] According to this aspect, the heating unit is a polyimide heater. With such a configuration, the heating unit can be made small-sized and low-cost.

[0020] [Example 1] Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. First, an overview of the printing apparatus 1A of Example 1 as an example of the printing apparatus 1 of the present invention will be described with reference to FIG. 1.

[0021] As shown in FIG. 1, the printing apparatus 1A of the present embodiment includes a setting unit 2 for setting a roll-shaped printing medium P, a winding unit 5 for winding the printing medium P conveyed from the setting unit 2, and a printing head 3 that discharges ink onto the printing surface P1 of the printing medium P conveyed in the conveyance direction A in the conveyance path from the setting unit 2 to the winding unit 5 to form an image. Further, it includes a platen 4 that supports the printing medium P in the image formation region where an image is formed by the printing head 3, a drying unit 10 for drying the ink landing on the printing surface P1, and conveyance rollers 6 as conveyance units of the printing medium P provided at a plurality of positions in the conveyance path of the printing medium P.

[0022] The print head 3 is located on the side of the printing medium P that is transported in the transport direction A, facing the printing surface P1. With the support surface P2 of the printing medium P opposite to the printing surface P1 supported by the platen 4, the print head 3 ejects ink onto the printing surface P1 to form an image. There are no particular limitations on the configuration of the print head 3. In this embodiment, the print head 3 is a so-called line head in which nozzles that eject ink over the entire width B of the printing medium P are arranged along the width B, and printing is performed when the print head is stopped. With this configuration of the print head 3 in this embodiment, the printing apparatus 1A in this embodiment can continuously transport the printing medium P by the transport rollers 6 and print with the print head 3.

[0023] Furthermore, as shown in Figure 1, a drying unit 10 for drying the ink discharged onto the printing medium P is provided downstream of the print head 3 in the transport direction A along the transport path of the printing medium P. In other words, the printing apparatus 1A of this embodiment comprises a transport roller 6 for transporting the printing medium P in the transport direction A, a print head 3 for printing on the printing medium P along the transport path of the printing medium P, and a drying unit 10 located downstream of the print head 3 in the transport direction A.

[0024] The details of the drying section 10, which is the main part of the printing apparatus 1A of this embodiment, will be described below with reference to Figures 2 to 4. As shown in Figures 2 and 3, the drying section 10A of the printing apparatus 1A of this embodiment has a plurality of support sections 11 that are arranged in a row with gaps G along the transport direction A and support the printing medium P. In detail, it has support sections 11A, 11B, 11C and 11D. Furthermore, the drying section 10A has a heating section 12 provided on each of the plurality of support sections 11 that heats the support sections 11.

[0025] In detail, the support section 11A has a heating section 12A, the support section 11B has a heating section 12B, the support section 11C has a heating section 12C, and the support section 11D has a heating section 12D. Here, the heating temperature of each of the heating sections 12 can be controlled individually. In this embodiment of the printing apparatus 1A, there are four support sections 11 and four heating sections 12, but there is no particular limit to the number of support sections 11 and heating sections 12 as long as there are multiple. Also, having a gap G does not mean that there is no space between the support sections 11, but that insulating material or the like may be placed between the support sections 11.

[0026] The printing apparatus 1A of this embodiment, with this configuration, can maintain each heating section 12 at a desired heating temperature while suppressing heat loss from the heating section 12 to adjacent support sections 11. Therefore, the printing apparatus 1A of this embodiment can efficiently heat the printing medium P while suppressing an increase in the driving power of the heating section 12. As shown in Figure 3, the support section 11 in the printing apparatus 1A of this embodiment is configured in an arc shape, but the configuration is not limited to this, and the support section 11 may be configured in a planar shape. However, since the support section 11 is configured in an arc shape, it is preferable that the support section 11 be configured in an arc shape because it improves adhesion to the printing medium P.

[0027] Here, the drying section 10D in a reference example printing apparatus 1D, which has one support section 11 and one heating section 12, will be described with reference to Figure 8. Note that the reference example printing apparatus 1D has the same configuration as the printing apparatus 1A in this embodiment, except for the configuration of the drying section 10. In the drying section 10D of the reference example printing apparatus 1D, when the printing medium P is transported continuously, the printing medium P at the inlet side of the drying section 10D comes into contact with the printing medium P at the same temperature as the ambient temperature, so a large amount of heat is absorbed by the printing medium P. When the temperatures of the temperature measurement points T1, T2, T3, T4 and T5 shown in Figure 8 are measured, at all temperature measurement points, the surface temperature of the support section 11 begins to decrease as soon as transport starts, and becomes almost constant after a certain period of time.

[0028] However, this temperature change (temperature drop) differs depending on the location of the support section 11. Specifically, the temperature drop is large from the inlet side to the central area, corresponding to temperature measurement points T1 to T3, but the temperature drop decreases from the central area to the outlet side, corresponding to temperature measurement points T3 to T5, and there is almost no temperature drop from temperature measurement point T4 onwards, which is about one-third of the way from the outlet side. This means that if the temperature setting of the heating section 12 is uniform throughout, the heating section 12 will be operated at approximately 100% capacity from the inlet side to about one-third of the way from the outlet side to the drying section 10D. Such operation increases the load on the heating section 12 and also increases the power consumption. On the other hand, by configuring the heating section 12 to be divided and driven independently, as in the printing apparatus 1A of this embodiment, the load on the heating section 12 can be reduced from about one-third of the way from the outlet side onwards, and power consumption can be kept low.

[0029] Furthermore, in the case where the support section 11 is an integrated unit, as in the example printing apparatus 1D, that is, the support section 11 is not divided in the transport direction A, the heat emitted from the heating section 12 flows to adjacent areas in the support section 11. Therefore, even if you try to set adjacent areas to different temperatures, heat will be transferred between them, and the temperature will not reach the set temperature. For example, if an adjacent area is set to a lower temperature than the area in question, the heating section 12 in that area will supply heat to the adjacent area in an attempt to eliminate the temperature difference between them, resulting in the consumption of more power than originally required.

[0030] Furthermore, if the heating unit 12 can be set to different temperatures in different regions of the support unit 11, even if the heating unit 12 is driven to achieve the same set temperature in different regions of the support unit 11, for example, the maintainable temperature will be lower in the region on the inlet side of the drying unit 10 corresponding to temperature measurement point T1, and higher in the region on the outlet side corresponding to temperature measurement point T5. Therefore, by dividing the support unit 11 and the heating unit 12 and configuring each heating unit 12 to be driven independently, as in the printing apparatus 1A of this embodiment, and setting the temperature on the inlet side of the drying unit 10 to a level where the amount of heat removed by the conveyed printing medium P balances the amount of heat supplied from the heating unit 12, it is possible to prevent overloading of the heating unit 12 on the inlet side (heating unit 12A) and reduce power consumption.

[0031] Furthermore, this configuration eliminates the need to install a high-output heating unit 12 at the inlet. This also contributes to reducing power consumption. The downstream heating unit 12D should be set to a temperature that considers maintaining the temperature in its installation area and ensuring drying capacity. Since the downstream heating unit 12D can maintain a higher temperature than the other heating units 12A, 12B, and 12C, it is possible to increase the set temperature of heating units 12A, 12B, 12C, and 12D in order towards the downstream side while simultaneously reducing the load on the heating units 12 and ensuring drying capacity.

[0032] To reiterate, in the reference example printing apparatus 1D, the drying section 10D may place an excessive load on the heating section 12. Furthermore, because the heating section 12, which is in contact with the printing medium P, is integrated in the transport direction A of the printing medium P, a temperature drop on the inlet side of the drying section 10 may also cause a temperature drop downstream, potentially leading to an increase in the load on the heating section 12 and the required power. Moreover, by raising the temperature on the inlet side of the drying section 10, the surface of the ink on the printing medium P dries rapidly near the inlet of the drying section 10, forming a film on the ink surface, which may hinder the movement of moisture and solvent from within the ink and actually impede drying. On the other hand, in the printing apparatus 1A of this embodiment, each of the support sections 11 is provided with a gap G between them, and each of the heating sections 12 can have its heating temperature controlled individually, thus reducing power consumption and efficiently heating the printing medium P while suppressing the formation of ink films.

[0033] Here, the printing apparatus 1A of this embodiment has a control unit 20 that can control the transport rollers 6 and the heating unit 12, as shown in Figure 4. The control unit 20 can control the transport rollers 6 so that they transport the printing medium P continuously. Furthermore, as described above, it has a plurality of support units 11, and the plurality of support units 11 can be described as having a first support unit (e.g., support unit 11A) arranged in the transport path and a second support unit (e.g., support units 11B, 11C, 11D) arranged downstream of the first support unit in the transport direction in the transport path. The heating unit 12 can be described as having a first heating unit (e.g., heating unit 12A) that heats the first support unit and a second heating unit (e.g., heating units 12B, 12C, 12D) that heats the second support unit.

[0034] Here, as shown in Figure 4, the control unit 20 has a temperature control unit 21 that controls the temperature of heating unit 12A, a temperature control unit 22 that controls the temperature of heating unit 12B, a temperature control unit 23 that controls the temperature of heating unit 12C, and a temperature control unit 24 that controls the temperature of heating unit 12D, each connected to the power supply 30. With this configuration, the control unit 20 can individually control the temperature of each heating unit 12. In other words, the control unit 20 can control the transport roller 6 so that it transports the printing medium P continuously, and can also control the heating units 12 so that the heating temperature of the first heating unit (e.g., heating unit 12A) is lower than the heating temperature of the second heating units (e.g., heating units 12B, 12C, 12D).

[0035] The printing apparatus 1A of this embodiment, with this configuration, can reduce the heat absorbed by the printing medium P when it comes into contact with the support part 11 (support part 11A) near the entrance of the drying section 10A, for example, when the printing medium P is at the same temperature as the ambient temperature. This reduces the amount of heat required for the heating section 12, thus reducing the need for large amounts of power. However, in the printing apparatus 1A of this embodiment, depending on the type of printing medium P and printing conditions, the control unit 20 can also control the heating section 12 such that the heating temperature of the first heating section (for example, heating section 12A) is higher than the heating temperature of the second heating sections (for example, heating sections 12B, 12C, 12D).

[0036] In the printing apparatus 1A of this embodiment, each heating element 12 is a polyimide heater. By configuring the heating elements 12 in this way, the heating elements 12 can be made smaller and less expensive. However, the heating elements 12 are not limited to polyimide heaters, and various other configurations can be used.

[0037] [Example 2] Next, the printing apparatus 1B of Example 2 will be described using Figures 5 and 6. Figure 5 corresponds to Figure 2 in the printing apparatus 1A of Example 1, and Figure 6 corresponds to Figure 3 in the printing apparatus 1A of Example 1. In Figures 5 and 6, components common to Example 1 are indicated by the same reference numerals, and detailed explanations will be omitted. Here, the printing apparatus 1B of this example has the same configuration as the printing apparatus 1A of Example 1, except for the configuration of the drying section 10 (drying section 10B). Therefore, with respect to parts other than those described below, the printing apparatus 1B of this example has the same characteristics as the printing apparatus 1A of Example 1.

[0038] As shown in Figures 5 and 6, in the printing apparatus 1B of this embodiment, the drying unit 10B has a fan 14 and an air blowing unit 13 that blows air from an air outlet 13A onto the printed surface P1 of the printing medium P printed by the print head 3. Also, as shown in Figures 5 and 6, the drying unit 10B has a fan 14 and a suction unit 16 in which a suction port 16A is located downstream of the air outlet 13A in the transport direction A of the transport path of the printing medium P. With this configuration, the printing apparatus 1B of this embodiment can dry the printing medium P not only by the heat from the heating unit 12 but also by the airflow, allowing for efficient drying of the printing medium P.

[0039] In this embodiment, the printing apparatus 1B is configured such that both the air outlet 13A and the suction outlet 16A are wider than the width of the printing medium P in the width direction B, which intersects with the transport direction A.

[0040] Furthermore, as shown in Figures 5 and 6, in the printing apparatus 1B of this embodiment, the air blower 13 has an airflow heating unit 15 that heats the airflow blown onto the printing surface P1. Therefore, the printing apparatus 1B of this embodiment is configured to blow heated airflow from the air outlet 13A. With this configuration, the printing apparatus 1B of this embodiment can blow heated gas onto the printing medium P, and can dry the printing medium P particularly efficiently.

[0041] [Example 3] Next, the printing apparatus 1C of Example 3 will be described with reference to Figure 7. Figure 7 corresponds to Figure 2 in the printing apparatus 1 of Example 1. In Figure 7, components common to both Example 1 and Example 2 are indicated by the same reference numerals, and detailed explanations will be omitted. Here, the printing apparatus 1C of this example has the same configuration as the printing apparatus 1 of Example 1 and Example 2, except for the configuration of the drying section 10C. Therefore, with respect to parts other than those described below, the printing apparatus 1C of this example has the same characteristics as the printing apparatus 1 of Example 1 and Example 2.

[0042] As described above, the printing apparatus 1B of Example 2 has fans 14 in the blowing section 13 and the suction section 16, and is configured to blow air and suction by driving the fans 14. On the other hand, the printing apparatus 1C of this embodiment is connected to external devices, a heated gas blowing device 41 and a suction device 42. Specifically, as shown in Figure 7, the blowing section 13 is connected to the heated gas blowing device 41, and the suction section 16 is connected to the suction device 42. The blowing section 13 and suction section 16 of the printing apparatus 1C of this embodiment have substantially the same configuration as the blowing section 13 and suction section 16 of the printing apparatus 1B of Example 2, except that they do not have fans 14 and an airflow heating section 15.

[0043] In this embodiment, the air blower section 13 of the printing apparatus 1C is configured to receive heated airflow from the heated gas blower 41 via the connecting pipe 17 in direction D1, and to blow air onto the printing surface P1 of the printing medium P. In addition, the suction section 16 of the printing apparatus 1C of this embodiment is configured to receive exhaust (gas in the drying section 10C) via the connecting pipe 18 to the suction device 42 in direction D2. With this configuration, the printing apparatus 1C of this embodiment has the same effects as the printing apparatus 1B of Embodiment 2.

[0044] The present invention is not limited to the embodiments described above, and can be realized in various configurations without departing from its spirit. For example, the technical features in the embodiments corresponding to the technical features in each embodiment described in the summary of the invention can be replaced or combined as appropriate in order to solve some or all of the above-described problems, or to achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate. [Explanation of Symbols]

[0045] 1…Printing device, 1A…Printing device, 1B…Printing device, 1C…Printing device, 1D…Printing device, 2…Setting unit, 3…Printing head, 4…Platen, 5…Winding unit, 6…Conveyor roller (conveyor unit), 10…Drying unit, 10A…Drying unit, 10B…Drying unit, 10C…Drying unit, 10D…Drying unit, 11…Support unit, 11A…Support unit (first support unit), 11B…Support unit (second support unit), 11C…Support unit, 11D…Support unit, 12…Heating unit, 12A…Heating unit (first Heating section), 12B... Heating section (second heating section), 12C... Heating section, 12D... Heating section, 13... Air blowing section, 13A... Air outlet, 14... Fan, 15... Airflow heating section, 16... Suction section, 16A... Suction outlet, 17... Connecting pipe, 18... Connecting pipe, 20... Control unit, 21... Temperature control unit, 22... Temperature control unit, 23... Temperature control unit, 24... Temperature control unit, 30... Power supply, 41... Heated gas blowing device, 42... Suction device, G... Gap, P... Printing medium, P1... Printing surface, P2... Support surface

Claims

1. A transport unit that transports the printing medium in the transport direction, A print head that prints on the printing medium along the transport path of the printing medium, A drying unit located downstream of the print head in the transport direction, Equipped with, The drying section is A plurality of support parts are arranged in a line with gaps along the transport direction to support the printing medium, A heating unit is provided in each of the multiple support units for heating the support unit, It has, A printing apparatus characterized in that each of the heating units can have its heating temperature controlled individually.

2. In the printing apparatus described in claim 1, The system includes a control unit capable of controlling the transport unit and the heating unit, The plurality of support parts include a first support part arranged in the transport path and a second support part arranged downstream of the first support part in the transport direction in the transport path. The heating unit comprises a first heating unit for heating the first support unit and a second heating unit for heating the second support unit. The printing apparatus is characterized in that the control unit controls the transport unit so that the transport unit transports the printing medium continuously, and controls the heating unit so that the heating temperature of the first heating unit is lower than the heating temperature of the second heating unit.

3. In the printing apparatus described in claim 1 or 2, The printing apparatus is characterized in that the drying section includes an air blowing section that blows air from an air blowing section onto the printed surface of the printing medium printed by the print head, and a suction section in the transport path where a suction port is located downstream of the air blowing section in the transport direction.

4. In the printing apparatus described in claim 3, The printing apparatus is characterized in that the air outlet and the suction outlet are arranged to be wider than the width of the printing medium in the width direction intersecting the conveying direction.

5. In the printing apparatus described in claim 4, The printing apparatus is characterized in that the blowing unit has an airflow heating unit that heats the airflow blown onto the printing surface, and blows the heated airflow from the air outlet.

6. In the printing apparatus described in claim 1 or 2, The printing apparatus is characterized in that the heating element is a polyimide heater.

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