Printing apparatus

Abstract

To suppress the occurrence of a malfunction due to reaction between ink in a nozzle and a volatile component of pretreatment liquid.SOLUTION: A printer 1 comprises: four heads which have nozzles for discharging ink; a platen 12 which has a support surface 12a that can support a printing medium applied with pretreatment liquid containing a volatile component that reacts with the ink; and four humidification air supply ports 81a1, 81b1, 82a1, 82b1. The four humidification air supply ports 81a1, 81b1, 82a1, 82b1 are provided in the periphery of the platen 12 in which the support surface 12a is arranged at a printing position P3 facing the nozzle, and supply the humidification air to the support surface 12a of the platen 12 that supports the printing medium.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a printing apparatus capable of printing by discharging ink onto a printing medium coated with a pretreatment liquid containing a volatile component that reacts with the ink.

Background Art

[0002] Patent Document 1 describes a printing apparatus including an inkjet head that evaporates a pretreatment agent before discharging color ink onto a printing medium coated with the liquid pretreatment agent and then discharges the color ink. Thereby, drying of the pretreatment agent can be appropriately promoted before discharging the color ink.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the printing apparatus described in Patent Document 1 above, when the pretreatment agent applied to the printing medium volatilizes during printing, the volatile component may react with the ink in the nozzles of the inkjet head. When the ink reacts with the volatile component of the pretreatment agent, there are problems such as the ink in the nozzles aggregating and causing ejection failures, or color changes occurring in the ink.

[0005] Therefore, an object of the present invention is to provide a printing apparatus capable of suppressing problems caused by the reaction between the ink in the nozzles and the volatile component of the pretreatment liquid.

Means for Solving the Problems

[0006] Book The printing apparatus of the invention is the 1From this perspective, the device comprises a head having a nozzle for ejecting ink, a platen having a support surface capable of supporting a printing medium coated with a pretreatment liquid containing volatile components that react with the ink, a humidified air supply port provided around the platen which is positioned at a printing position where the support surface faces the nozzle and supplies humidified air to the support surface of the platen which supports the printing medium, a pair of inner walls spaced apart from each other and both extending in one direction, and a moving mechanism between the pair of inner walls which moves the platen in the one direction between the printing position and a support position which is different from the printing position and where the platen supports the printing medium, wherein the humidified air supply port is located between the pair of inner walls in a direction perpendicular to the one direction. The device further comprises a fan and a suction port provided along the inner wall from which air is drawn in by the fan, wherein the humidified air supply port is located in the perpendicular direction between the humidified air supply port and the suction port, at least a portion of the platen which is positioned at the printing position. The printing apparatus of the present invention is the 2 From this perspective, the printer comprises a head having a nozzle for ejecting ink, a platen having a support surface capable of supporting a printing medium coated with a pretreatment liquid containing volatile components that react with the ink, and humidified air supply ports provided around the platen, which is positioned at a printing position where the support surface faces the nozzle, and which supply humidified air to the support surface of the platen that supports the printing medium, wherein the support surface has a rectangular shape, and at least four humidified air supply ports are provided, and the four humidified air supply ports are positioned in a plan view to correspond to the four corners of the support surface, respectively. The printing apparatus of the present invention is the 3From this perspective, the printer comprises a head having a nozzle for ejecting ink, a platen having a support surface capable of supporting a printing medium coated with a pretreatment liquid containing volatile components that react with the ink, and a humidified air supply port provided around the platen, which is positioned at a printing position where the support surface faces the nozzle, and which supplies humidified air to the support surface of the platen that supports the printing medium, wherein the support surface has a rectangular shape, and at least two humidified air supply ports are provided, and the two humidified air supply ports are positioned in a plan view to correspond to the center of two opposing sides of the support surface, respectively. [Effects of the Invention]

[0007] According to the printing apparatus of the present invention, humidified air can be supplied from a humidified air supply port to the support surface of the platen positioned at the printing location. Therefore, when printing by ejecting ink from the nozzles of the print head onto a printing medium coated with a pretreatment liquid, it becomes possible to supply humidified air onto the printing medium. This makes it difficult for volatile components of the pretreatment liquid coated on the printing medium to evaporate at the printing location, and also makes it difficult for the volatile components of the pretreatment liquid themselves to reach the nozzles. Consequently, it is possible to suppress malfunctions caused by reactions between the ink in the nozzles and the volatile components of the pretreatment liquid. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic perspective view of a printing apparatus according to one embodiment of the present invention. [Figure 2] Figure 1 is a plan view showing the internal structure of the printing apparatus. [Figure 3] Figure 1 is a front view showing the internal structure of the printing apparatus. [Figure 4] This is a cross-sectional view along the line IV-IV shown in Figure 3. [Figure 5] This is a schematic diagram of the carriage as viewed from below. [Figure 6] (a) is a front view of the suction mechanism, and (b) is a side view of the suction mechanism. [Figure 7]This is a cross-sectional view along the line VII-VII shown in Figure 3. [Figure 8] This figure shows the situation when humidified air is supplied from the humidified air supply port of the printing device shown in Figure 1. [Figure 9] This block diagram shows the electrical configuration of the printing apparatus shown in Figure 1. [Figure 10] This flowchart shows an example of the processing procedure executed when a print start command is input to the printing device shown in Figure 1. [Figure 11] This is a schematic plan view of a printing apparatus according to a modified example of the present invention. [Figure 12] Figure 11 is a front view of the main parts of the printing apparatus. [Figure 13] This figure shows the situation when humidified air is supplied from the humidified air supply port of the printing device shown in Figure 11. [Figure 14] This is a schematic plan view of a printing apparatus according to another modified example of the present invention. [Modes for carrying out the invention]

[0009] The printing apparatus 1 of the present invention will be described with reference to the drawings. In the following description, the vertical and horizontal directions (the "one direction" in the present invention) are defined based on the state in which the printing apparatus 1 is installed for use (the state in Figure 1), and the left and right directions (the "orthogonal directions" in the present invention) are defined when viewing the printing apparatus 1 from the front. In the following description, the left and right directions may also be referred to as the main scanning direction, and the horizontal directions as the secondary scanning direction.

[0010] The printing device 1 shown in FIG. 1 is an inkjet printer that ejects ink onto a printing medium to perform printing. The printing device 1 can print a color image on the printing medium using five colors of ink: white, black, yellow, cyan, and magenta. The printing medium is cloth, paper, etc. In the present embodiment, as the printing medium, for example, a T-shirt containing polyester fibers is referred to. When the printing device 1 executes printing on the printing medium (T-shirt), the printing medium pre-coated with a pretreatment liquid is placed on the platen 12. The pretreatment liquid reacts with the ink ejected onto the pretreatment liquid to aggregate the components of the ink and prevent bleeding. The volatile components of the pretreatment liquid contain organic acids such as formic acid.

[0011] Hereinafter, the white ink among the five colors of ink is referred to as "white ink". When collectively referring to the four colors of ink: black, cyan, yellow, and magenta, or when not specifying any one of them, they are referred to as "color ink". When collectively referring to white ink and color ink, or when not specifying any one of them, they are simply referred to as "ink". The white ink is used for printing as a part representing the white color of the image or as a base for the color ink. The color ink is ejected onto the base formed by the white ink and is used for printing a color image.

[0012] Referring to FIGS. 1 to 3, the external configuration of the printing device 1 will be described. As shown in FIG. 1, the printing device 1 includes a housing 8, a platen 12, a transport mechanism 14, an operation unit 15, and a display screen 16. The housing 8 has a substantially rectangular parallelepiped shape, and a rectangular platen opening 13 is formed substantially at the center in the left-right and up-down directions on the front surface. Inside the housing 8, five cartridges (not shown) containing five colors of ink are stored. The platen 12 is composed of a plate-like member having a substantially rectangular planar shape. The upper surface of the platen 12 is a support surface 12a that supports the printing medium. The support surface 12a has a square shape.

[0013] <映 The operation unit 15 is provided at both left and right ends of a platen support portion 37 (described later) that protrudes forward from the platen opening 13. The operation unit 15 outputs information according to operations by the user to a control unit 80 described later. By operating the operation unit 15, the user can input to the control unit 80 a print start command (including print data) for starting printing by the printing apparatus 1 and the like. The display screen 16 is provided at the upper right side of the front surface of the housing 8, which is more to the right than the platen opening 13. The display screen 16 displays various types of information. Accordingly, the operator operates the printing apparatus 1 on the front side of the printing apparatus 1.

[0014] The conveyance mechanism (the “moving mechanism” of the present invention) 14 conveys the platen 12 on which the print medium is placed between the inside and the outside of the housing 8 through the platen opening 13. The platen 12 is disposed at a printing position P3 (the position indicated by the two-dot chain line in FIG. 2) inside the housing 8 shown in FIG. 2, and ink is ejected from a head 30 described later to perform printing. As shown in FIG. 2, the conveyance mechanism 14 includes a platen support portion 37, a pair of left and right rails 38, a transmission member 39, and a sub-scanning motor 26 (see FIG. 9).

[0015] As shown in FIGS. 2 and 3, the platen support portion 37 supports the platen 12 from below. The pair of left and right rails 38 extend in the front-rear direction and support the platen support portion 37 so as to be movable in the front-rear direction. The front ends of the pair of rails 38 are in front of the front surface of the housing 8. The transmission member 39 is connected to the platen support portion 37 and the sub-scanning motor 26, and moves the platen support portion 37 in the front-rear direction along a conveyance path defined by the pair of left and right rails 38 in response to the drive of the sub-scanning motor 26. That is, the platen 12 moves in the front-rear direction by the drive of the sub-scanning motor 26. Thus, the conveyance mechanism 14 moves the platen 12 in the front-rear direction between a pair of inner walls 71 and 72 described later. The left-right direction is the scanning direction of the head 30 described later, and in the present embodiment, the left-right direction is the main scanning direction.

[0016] With the platen 12 positioned in front of the front of the housing 8, that is, outside the housing 8, the operator places the printing medium on the support surface 12a of the platen 12. In other words, the position of the platen 12 shown in Figure 2 is the support position P1 where the platen 12 supports the printing medium. Before printing on the printing medium, the platen 12 moves from the support position P1 to the pre-printing standby position P2 (the position shown by the dashed line in Figure 2). The pre-printing standby position P2 is behind the printing position P3 and is at the rear end of the transport path of the platen 12. The platen 12 positioned at the pre-printing standby position P2 does not face the head 30, which will be described later, even when it moves in the main scanning direction. The printing position P3 is a position in the transport path of the platen 12 that overlaps vertically with the movement path of the head 30 in the main scanning direction, which will be described later. The movement path of the head 30 in the main scanning direction is the path between the rear end of the rearmost head 30 (white head 31) and the front end of the frontmost head 30 (color head 34).

[0017] The internal structure of the printing apparatus 1 will be explained with reference to Figures 2 to 8. As shown in Figure 2, the printing apparatus 1 includes a frame 2, a pair of inner walls 71 and 72, partition plates 28 and 29 (see Figure 3), heads 31 to 34, a moving mechanism 77, suction mechanisms 73 and 74 (see Figure 3), two humidified air supply pipes 81 and 82 (see Figure 4), and a humidifier 86 (see Figure 3) inside the housing 8.

[0018] As shown in Figures 2 to 4, the frame 2 is constructed in a grid pattern by multiple shafts extending in the front-to-back direction, including shafts 57 and 58; multiple shafts extending in the left-to-right direction; and multiple shafts extending in the up-to-down direction, including shafts 55 and 56. The moving mechanism 77 includes a guide shaft 20 and a carriage 6 fixed to the frame 2. As shown in Figure 2, the guide shaft 20 is composed of a front shaft 21, a rear shaft 22, a left shaft 23, and a right shaft 24.

[0019] As shown in Figure 2, the front shaft 21 is positioned at the front end of the frame 2 and extends horizontally from the left end to the right end of the frame 2. The rear shaft 22 is positioned approximately in the center of the frame 2 in the front-to-back direction and extends horizontally from the left end to the right end of the frame 2. The left shaft 23 is positioned at the left end of the frame 2 and extends horizontally from the left end of the front shaft 21 to the left end of the rear shaft 22. The right shaft 24 is positioned at the right end of the frame 2 and extends horizontally from the right end of the front shaft 21 to the right end of the rear shaft 22. The front shaft 21 and the rear shaft 22 support the carriage 6. The transport mechanism 14 is fixed to the frame 2.

[0020] The pair of inner walls 71 and 72 are arranged facing each other and spaced apart from each other along the left-right direction, as shown in Figures 2 to 4. For example, as shown in Figure 2, the pair of inner walls 71 and 72 are arranged in a plan view, flanking the printing position P3 where the platen 12 is placed, in the left-right direction. The inner walls 71 and 72 extend in the vertical and front-back directions below the guide shaft 20 and are fixed to the frame 2. Inner wall 71 is located to the left of the platen 12 placed at the printing position P3 and is fixed to shaft 57. Inner wall 72 is located to the right of the platen 12 placed at the printing position P3 and is fixed to shaft 58. At least a portion of the inner walls 71 and 72 is located between the front shaft 21 and the rear shaft 22 in the front-back direction, as shown in Figure 2.

[0021] As shown in Figures 3 and 4, the partition plate 28 is fixed to the frame 2 below the guide shaft 20 and to the left of the inner wall 71. The partition plate 28 extends in both the front-to-back and left-to-right directions. The right end of the partition plate 28 is connected to the lower end of the inner wall 71.

[0022] As shown in Figures 3 and 4, the partition plate 29 is fixed to the frame 2 below the guide shaft 20 and to the right of the inner wall 72. The partition plate 29 extends in the front-to-back and left-to-right directions. The left end of the partition plate 29 is connected to the lower end of the inner wall 72.

[0023] As shown in Figure 4, a circular supply port 75 is formed on the right front of the partition plate 28, penetrating the partition plate 28 vertically in a plan view. A circular supply port 76 is formed on the left front of the partition plate 29, penetrating the partition plate 29 vertically in a plan view. The positional relationship between the supply ports 75 and 76 is not particularly limited, but in this embodiment, in the front-to-back direction, the supply port 75 is formed in front of the supply port 76. Piping (not shown) is connected to these supply ports 75 and 76 and is connected to humidified air supply pipes 81 and 82, which will be described later.

[0024] As shown in Figure 2, the carriage 6 is supported by the front shaft 21 and the rear shaft 22 so as to be movable in the main scanning direction. The carriage 6 is plate-shaped and extends in the front-rear, left-right, and right directions. The carriage 6 extends from the front shaft 21 to the rear shaft 22.

[0025] As shown in Figures 2 and 5, the carriage 6 is equipped with white heads 31 and 32 and color heads 33 and 34. These white heads 31 and 32 and color heads 33 and 34 constitute the "head" of the present invention.

[0026] The white heads 31 and 32 and the color heads 33 and 34 each have the same structure and, in this embodiment, are rectangular parallelepipeds. Hereinafter, when referring to the white heads 31 and 32 and the color heads 33 and 34 collectively, or when not specifying any of them, they will be referred to as "head 30". The white heads 31 and 32 are located at the rear of the carriage 6, as shown in Figure 5. White head 31 is located at the right rear of the carriage 6. White head 32 is located to the left of white head 31 and is shifted forward relative to white head 31. The rear of white head 32 overlaps with the front of white head 31 in the left-right direction.

[0027] As shown in Figures 2 and 5, the color heads 33 and 34 are positioned in front of the white heads 31 and 32. The color heads 33 and 34 are positioned in the same location as the white heads 31 and 32 in the left-right direction. In other words, the white heads 31 and 32 and the color heads 33 and 34 are arranged side by side along the sub-scanning direction. The color head 34 is positioned to the left of the color head 33 and is shifted in front of the color head 33. The rear of the color head 34 overlaps with the front of the color head 33 in the left-right direction.

[0028] As shown in Figure 5, a nozzle surface 311 is provided on the lower surface of the white head 31. The nozzle surface 311 extends in the front-back, left-right, and right directions. Multiple nozzle rows 312 are formed on the nozzle surface 311. The multiple nozzle rows 312 are arranged in the left-right direction. Each nozzle row 312 consists of multiple nozzles 313 arranged in a single row at equal intervals in the front-back direction. The multiple nozzles 313 are openings and eject white ink downwards.

[0029] Similar to the configuration of the white head 31, nozzle surfaces 321, 331, and 341 are provided on the lower surfaces of the white head 32, color heads 33, and 34, respectively. The nozzle surfaces 321, 331, and 341 extend in the front-back, left-right, and right directions. Multiple nozzle rows 322, 332, and 342 are formed on the nozzle surfaces 321, 331, and 341, respectively. The multiple nozzle rows 322, 332, and 342 are arranged in the left-right direction. Each of the multiple nozzle rows 322, 332, and 342 consists of multiple nozzles 323, 333, and 343 arranged in a single row at equal intervals in the front-back direction.

[0030] Multiple nozzles 323 eject white ink downwards. Multiple nozzle rows 332 each correspond to a different color ink. That is, multiple nozzles 333 eject the color ink of the color corresponding to each of the multiple nozzle rows 332 downwards. Multiple nozzle rows 342 each correspond to a different color ink. Multiple nozzles 343 eject the color ink of the color corresponding to each of the multiple nozzle rows 342 downwards.

[0031] As shown in Figures 2 and 5, the separation distance between the white head 31 and the color head 33 in the sub-scanning direction is greater than the separation distance between the two white heads 31 and 32 in the main scanning direction. The separation distance between the white head 32 and the color head 34 in the sub-scanning direction is also greater than the separation distance between the two white heads 31 and 32 in the main scanning direction.

[0032] The moving mechanism 77 includes a drive belt 98 and a main scanning motor 99. The drive belt 98 is connected to the rear end of the carriage 6. The drive belt 98 is mounted on the rear shaft 22 and extends in the left-right direction. The left end of the drive belt 98 is connected to the main scanning motor 99. When the main scanning motor 99 is driven, the drive belt 98 moves the carriage 6 in the left-right direction along the front shaft 21 and the rear shaft 22. In other words, the moving mechanism 77 moves the carriage 6 on which the head 30 is mounted in the main scanning direction. Figures 2 and 3 show the state in which the carriage 6 is located at the right end of the movement range R.

[0033] In Figures 2 and 3, the movement range R of the head 30 is shown at the center of the carriage 6 in the left-right direction. As shown in Figure 3, the head 30 is mainly positioned in one of three positions by the movement mechanism 77: maintenance position B1, ejection position B2, and head standby position B3. Maintenance position B1 is at the left end of the movement range R of the head 30, and is the position where the head 30 is maintained by a maintenance unit such as a wiper or cap (not shown). When not printing, the printing device 1 moves the head 30 to maintenance position B1 and performs maintenance by the maintenance unit. Ejection position B2 is a position between maintenance position B1 and head standby position B3 in the main scanning direction, and above the platen 12 located at the printing position P3. With the head 30 positioned at ejection position B2, the head 30 ejects ink according to the print data, and printing is performed on the printing medium on the platen 12 located at the printing position P3. The head standby position B3 is located at the right end of the movement range R of the head 30, and is the position where an operator is positioned when performing operations such as cleaning on the head 30. The printing device 1 moves the head 30 to the head standby position B3 and puts it into standby mode, for example, based on instructions input from the control unit 15 by the user.

[0034] The printing apparatus 1 moves the platen 12 in the sub-scanning direction by driving the sub-scanning motor 26 at the printing position P3, and moves the carriage 6 in the main scanning direction by driving the main scanning motor 99 at the ejection position B2, thereby moving the printing medium relative to the head 30 in the sub-scanning direction and the main scanning direction.

[0035] The operation of moving the head 30 in the main scanning direction and ejecting ink onto the printing medium when the head 30 is facing the printing medium is called "ejection scanning." The printing device 1 prints on the printing medium by repeating ejection scanning and moving the platen 12 in the sub-scanning direction. For example, during ejection scanning, the printing device 1 ejects white ink from the white heads 31 and 32 to form a base layer on the printing medium. On top of the base layer formed on the printing medium during ejection scanning, the printing device 1 ejects color ink from the color heads 33 and 34 to print a color image.

[0036] As shown in Figure 3, the suction mechanisms 73 and 74 draw in humidified air, which will be described later. In the main scanning direction, the suction mechanism 73 is located inside the housing 8 (see Figure 1) to the left of the transport mechanism 14, and the suction mechanism 74 is located inside the housing 8 to the right of the transport mechanism 14. Since the suction mechanisms 73 and 74 have a symmetrical configuration, the configuration of the suction mechanism 73 will be described below, and the description of the suction mechanism 74 will be omitted.

[0037] As shown in Figure 6, the suction mechanism 73 has an inner wall 71, three fans 94, and a filter unit 48. The right side 79 of the inner wall 71 extends in the vertical and front-to-back directions. A slit-shaped suction port 713, which is long in the front-to-back direction, is formed on the upper surface of the inner wall 71.

[0038] As shown in Figure 6(a), the inner wall 71 has a fixing plate 70 and a housing section 49. The fixing plate 70 is a plate-shaped portion that extends in the left-right direction at the upper end of the inner wall 71. As shown in Figure 4, the fixing plate 70 is fixed to a shaft 57 that extends in the front-rear direction. The housing section 49 is box-shaped and detachably houses a rectangular parallelepiped filter unit 48 that is long in the front-rear direction inside the inner wall 71. The filter unit 48 has a filter and a support that supports the filter. The filter is, for example, a resin filter with a plurality of minute pores formed therein, which adsorbs and collects foreign matter such as mist and dust from the air.

[0039] The three fans 94 are located at the bottom of the left side 78 of the inner wall 71, as shown in Figure 6(b). The three fans 94 are arranged at approximately equal intervals in the front-to-back direction and have the following configuration. The intake port 945 of the fan 94 is located to the right of the fan 94, as shown in Figure 6(a), and the exhaust port 946 of the fan 94 is located to the left of the fan 94. That is, the intake port 945 is on the platen 12 side located at the printing position P3 relative to the fan 94, and the exhaust port 946 is on the left side of the housing 8 relative to the fan 94. The intake port 945 of the fan 94 is connected to the bottom of the left side 78 of the inner wall 71.

[0040] The suction port 713 is positioned above the intake port 945 of the fan 94. As shown in Figure 4, in the suction mechanism 73, when each fan 94 is driven, the air drawn into the inner wall 71 from the suction port 713 of the inner wall 71 passes through the filter of the filter unit 48, and the air from which foreign matter has been collected is discharged from the space inside the inner wall 71 through the intake port 945 of the fan 94 and the exhaust port 946. That is, when the fan 94 is driven, as shown in Figure 6(a), air flows through the space enclosed by the right side 79 and the left side 78 of the inner wall 71 as indicated by arrow K.

[0041] As shown in Figure 4, the suction mechanism 74 has an inner wall 72, three fans (not shown), and a filter unit (not shown) corresponding to the inner wall 71, three fans 94, and filter unit 48 of the suction mechanism 73. A long, slit-shaped suction port 723 corresponding to the suction port 713 is formed on the upper surface of the suction mechanism 74. When each fan of the suction mechanism 74 is driven, air flows from the suction port 723 into the space inside the inner wall 72. The air then passes through the filter of the filter unit as it flows from the top to the bottom of the space. Finally, the air flows from the bottom of the space to the right where the fans are located and is discharged from the space.

[0042] Furthermore, the suction mechanisms 73 and 74 only need to have inner walls 71 and 72 and a fan 94, respectively, and do not necessarily need to have a filter unit 48.

[0043] The humidifier (the "humidified air generating unit" of the present invention) 86 shown in Figure 3 supplies humidified air to a supply port 75 located to the left of the suction mechanism 73 and to a supply port 76 located to the right of the suction mechanism 74. The humidifier 86 is located inside the housing 8 and below the partition plate 29. The humidifier 86 has a storage unit (not shown), a humidification drive unit 861 (see Figure 9), an intake port 89 (see Figure 3) for drawing air into the humidifier 86, tubes 87 and 88 (see Figure 3), and fans 862 and 863 (see Figure 9). The storage unit stores the liquid used for humidification (for example, water). A water supply pipe may be connected to the storage unit, and water may be supplied to the storage unit from an external device such as a water supply and a water tank (not shown).

[0044] The humidification drive unit 861 humidifies the air taken into the humidifier 86 via the intake port 89 using the liquid stored in the storage unit. The humidification drive unit 861 may humidify the air using any method, such as steam, vaporization, ultrasonic, or electrolysis. One end of the tube 87 is connected to the humidifier 86, and the other end is connected to the supply port 75. The supply port 75 is located below the head 30, which is positioned on the left end of the movement range R (maintenance position B1). One end of the tube 88 is connected to the humidifier 86, and the other end is connected to the supply port 76. The supply port 76 is located below the head 30, which is positioned on the right end of the movement range R (head standby position B3).

[0045] Fan 862 supplies humidified air from the humidification drive unit 861 to the supply port 75 via the tube 87 shown in Figure 3. Fan 863 supplies humidified air from the humidification drive unit 861 to the supply port 76 via the tube 88 shown in Figure 3. The humidified air supplied to the supply port 75 is sent to the support surface 12a of the platen 12 via the humidified air supply pipe 81, which will be described later. Similarly, the humidified air supplied to the supply port 76 is also sent to the support surface 12a of the platen 12 via the humidified air supply pipe 82, which will be described later. In other words, the humidified air supplied from the humidifier 86 is sent towards the printing medium supported by the platen 12.

[0046] As shown in Figure 4, the humidified air supply pipe 81 is supported by a support frame 811. The support frame 811 is fixed to the frame 2 in a position forward of the platen 12 (or a portion of the platen 12 if a portion of the platen 12 is at the printing position P3) in the front-rear direction. The humidified air supply pipe 81 is fixed to the center of the support frame 811 in the left-right direction. The humidified air supply pipe 81 has two flow paths 81a and 81b arranged side by side in the left-right direction. The left flow path 81a extends to the left as it goes from front to rear. The right flow path 81b extends to the right as it goes from front to rear. These two flow paths 81a and 81b merge at their front ends. The front ends of the merging section of flow paths 81a and 81b and the supply port 75 are connected by piping (not shown). Humidified air supply ports 81a1 and 81b1 are formed at the rear ends of each flow path 81a and 81b to supply humidified air.

[0047] As shown in Figure 4, the humidified air supply pipe 82 is supported by a support frame 821. The support frame 821 is fixed to the frame 2 in the front-rear direction, positioned behind the platen 12 (or a portion of the platen 12 if a portion of the platen 12 is at the printing position P3). The humidified air supply pipe 82 is fixed to the center of the support frame 821 in the left-right direction. As shown in Figure 4, the humidified air supply pipe 82 has a similar configuration to the humidified air supply pipe 81 and has two flow paths 82a and 82b arranged side by side in the left-right direction. The left flow path 82a extends to the left as it moves from rear to front. The right flow path 82b extends to the right as it moves from rear to front. These two flow paths 82a and 82b merge at their rear ends. The rear ends of the merging section of flow paths 82a and 82b are connected to the supply port 76 by piping (not shown). Humidified air supply ports 82a1 and 82b1 are formed at the front end of each flow path 82a and 82b to supply humidified air.

[0048] Furthermore, the support frames 811 and 821 may have hollow tubes, and these hollow tubes may be connected to the humidified air supply pipes 81 and 82. This allows the humidified air supplied to the support frames 811 and 821 to be supplied from the humidified air supply ports 81a1, 81b1, 82a1, and 82b1 of the humidified air supply pipes 81 and 82. In this case, the support frames 811 and 821 may be connected to the supply ports 75 and 76 or the humidifier 86 by piping (not shown), and humidified air will be supplied to the support frames 811 and 821.

[0049] These four humidified air supply ports 81a1, 81b1, 82a1, and 82b1 are provided around the platen 12 located at the printing position P3 shown in Figures 4 and 8, and face the support surface 12a side of the platen 12. Two of the humidified air supply ports 81a1 and 81b1 face backward, and the two humidified air supply ports 82a1 and 82b1 face forward. In addition, the humidified air supply ports 81a1, 81b1, 82a1, and 82b1 are positioned between a pair of inner walls 71 and 72 in the left-right direction. Furthermore, in the left-right direction, the humidified air supply ports 81a1, 81b1, 82a1, and 82b1 are positioned between the humidified air supply ports 81a1, 81b1, 82a1, and 82b1 and the suction ports 713 and 723, where the left and right ends of the platen 12 located at the printing position P3 are positioned. For example, the four humidified air supply ports 81a1, 81b1, 82a1, and 82b1 are positioned in pairs, corresponding to the center of the opposing front and rear edges of the support surface 12a of the platen 12 located at the printing position P3. Furthermore, as shown in Figure 7, the four humidified air supply ports 81a1, 81b1, 82a1, and 82b1 are positioned above the platen 12 such that the distance from their central axis (the central axis passing through the center of the opening) to the support surface 12a of the platen 12 is a predetermined distance T1 in the vertical direction. The four humidified air supply ports 81a1, 81b1, 82a1, and 82b1 open toward the spatial area on the support surface 12a of the platen 12 located at the printing position P3 (the area between the head 30 and the support surface 12a in the vertical direction).

[0050] As shown in Figure 8, the humidified air supplied from these four humidified air supply ports 81a1, 81b1, 82a1, and 82b1 is supplied from the center of the front and rear edges of the platen 12, which is located at the printing position P3, towards the left and right edges of the platen 12 in a plan view. As a result, a large amount of humidified air is supplied to the rear region PA (the area shown by hatching in Figure 8), where the front-to-back transport path of the platen 12 and the movement paths of the two white heads 31 and 32 in the main scanning direction overlap vertically, and to the front region PB (the area shown by hatching in Figure 8), where the front-to-back transport path of the platen 12 and the movement paths of the two color heads 33 and 34 in the main scanning direction overlap vertically, in the space between the platen 12 and the head 30. At this time, when the suction mechanisms 73 and 74 are driven, the humidified air supplied to the rear region PA and the front region PB flows outward along the left-right direction, making it easier to draw in through the suction ports 713 and 723.

[0051] Referring to Figure 9, the electrical configuration of the printing device 1 will be explained. The printing device 1 has a control unit 80. The control unit 80 is equipped with a CPU 80a, ROM 80b, RAM 80c, and flash memory 80d. The CPU 80a controls the printing device 1 and is electrically connected to the ROM 80b, RAM 80c, and flash memory 80d. The ROM 80b stores control programs for the CPU 80a to control the operation of the printing device 1, information required by the CPU 80a when executing various programs, etc. For example, the ROM 80b stores the positions of the carriage 6 (head 30) based on the rotation angle of the main scanning motor 99, and stores the positions of the platen 12 based on the rotation angle of the sub-scanning motor 26. The RAM 80c temporarily stores various data used in the control program, etc. The flash memory 80d is non-volatile and stores printing data, etc. for printing.

[0052] As shown in Figure 9, the control unit 80 is electrically connected to the main scanning motor 99, the sub-scanning motor 26, the four head drive units 301-304, the humidifier 86, the fan 94, and the operating unit 15. The main scanning motor 99, the sub-scanning motor 26, the head drive units 301-304, the humidifier 86, and the fan 94 are driven by control from the control unit 80.

[0053] Encoders 991 and 261 are provided for the main scanning motor 99 and the sub-scanning motor 26, respectively. Encoder 991 detects the rotation angle of the main scanning motor 99 and outputs the detection result to the control unit 80. Encoder 261 detects the rotation angle of the sub-scanning motor 26 and outputs the detection result to the control unit 80.

[0054] The four head drive units 301 to 304 correspond to the white heads 31 and 32 and the color heads 33 and 34 in order, and are contained within these heads 31 to 34. Each head drive unit 301 to 304 is composed of multiple drive elements (piezoelectric elements or heating elements) capable of selectively supplying energy to the ink in multiple individual channels that communicate with multiple nozzles of the head 30. By being driven, each of these head drive units 301 to 304 supplies energy to the ink in the white heads 31 and 32 and the color heads 33 and 34, and selectively ejects ink from the corresponding nozzles 313, 323, 333, and 343.

[0055] <Printing control> Referring to Figure 10, the control by the control unit 80 when printing an image onto a printing medium will be explained. When the user operates the operation unit 15 and a print start command is input to the printing device 1, the control unit 80 reads the control program from the ROM 80b and executes the flow shown in Figure 10. The flow shown in Figure 10 will be explained below.

[0056] The control unit 80 first determines whether or not a print start command has been input (S1). Before the user operates the operation unit 15 to input a print command, the user applies the pretreatment liquid to the printing medium. The pretreatment liquid may be applied by an application mechanism such as a spray or head, which is provided separately from the printing device 1, when the print start command is input. The printing medium (T-shirt) is then placed on the support surface 12a of the platen 12 before the volatile components of the pretreatment liquid applied to the printing medium have finished evaporating. In other words, the printing medium can be placed on the platen 12 immediately after the pretreatment liquid has been applied, without any special processing such as drying. In this embodiment, when S1 is processed, the printing medium, immediately after the pretreatment liquid has been applied, is supported on the platen 12. Therefore, during the printing process described later, organic acids evaporate from the pretreatment liquid applied to the printing medium. The platen 12 is positioned at the support position P1 when not printing. When not printing, the printing apparatus 1 normally has the print head 30 positioned at maintenance position B1, and the multiple nozzles of the print head 30 are capped by a cap of a maintenance unit (not shown).

[0057] If no print start command is entered (S1: NO), S1 is repeated until a print start command is entered. On the other hand, if a print start command is entered (S1: YES), the control unit 80 controls the humidifier 86 so that the supply of humidified air begins from the four humidified air supply ports 81a1, 81b1, 82a1, and 82b1 (S2). In other words, the control unit 80 drives the humidification drive unit 861 to generate humidified air. Then, it drives the fans 862 and 863 to supply humidified air from the four humidified air supply ports 81a1, 81b1, 82a1, and 82b1. As shown in Figure 8, the supply of humidified air from the four humidified air supply ports 81a1, 81b1, 82a1, and 82b1 supplies humidified air to the spatial area including the rear area PA and the front area PB. At this time, the control unit 80 also drives the fans 94 of the suction mechanisms 73 and 74. This creates a flow of humidified air from the humidified air supply ports 81a1, 81b1, 82a1, and 82b1 through the rear region PA and the front region PB to the suction ports 713 and 723.

[0058] Next, the control unit 80 executes the printing process (S3). Based on the detection result from the encoder 261, the control unit 80 controls the sub-scanning motor 26 to move the platen 12 from the support position P1 to the pre-print standby position P2. After this, the control unit 80 controls the sub-scanning motor 26 based on the detection result from the encoder 261 to move the platen 12 from the pre-print standby position P2 to the printing position P3. At this time, the control unit 80 also performs uncapping, separating the cap from the head 30.

[0059] Then, the control unit 80 controls the main scanning motor 99 based on the detection result from the encoder 991, moving the carriage 6 from the maintenance position B1 to the ejection position B2, so that the head 30 faces the printing medium placed on the platen 12.

[0060] The control unit 80 controls the head drive units 301-304, the main scanning motor 99, and the sub-scanning motor 26 when the platen 12 is in the printing position P3 and the carriage 6 is in the ejection position B2, and prints on the printing medium by alternately repeating ejection scanning and the forward movement of the platen 12. In other words, when printing on the printing medium, the platen 12 is transported forward from the pre-printing standby position P2 to the printing position P3. First, ink is ejected from the nozzles of the white heads 31 and 32 onto the printing medium coated with pre-treatment liquid, forming a base layer. Then, ink is ejected from the nozzles of the color heads 33 and 34 onto the base layer formed on the printing medium after passing through the white heads 31 and 32, forming an image. The white areas of the image are represented by the base layer formed with white ink. Therefore, no color ink is ejected onto this base layer.

[0061] Since humidified air is supplied from the four humidified air supply ports 81a1, 81b1, 82a1, and 82b1 even before the printing process is executed, humidified air is supplied to the printing medium when printing is performed. In other words, a layer of humidified air exists on the printing medium. This makes it difficult for volatile components of the pretreatment liquid applied to the printing medium to evaporate. Furthermore, even if volatile components of the pretreatment liquid do evaporate, these volatile components are less likely to reach the nozzles of the head 30 facing the printing medium. When printing on the printing medium based on the print data is completed with this layer of humidified air present on the printing medium, the control unit 80 controls the humidifier 86 to stop supplying humidified air from the four humidified air supply ports 81a1, 81b1, 82a1, and 82b1 (S4). At this time, the control unit 80 also stops driving the fans 94 of the suction mechanisms 73 and 74. This stops the flow of humidified air from the humidified air supply ports 81a1, 81b1, 82a1, and 82b1 to the rear region PA and the front region PB, and from the rear region PA and the front region PB to the suction ports 713 and 723.

[0062] Furthermore, the control unit 80 controls the sub-scanning motor 26 based on the detection result from the encoder 261 to stop the platen 12 at the support position P1. The user removes the printed medium with the image formed on it from the platen 12 positioned at the support position P1. At this time, the control unit 80 controls the main scanning motor 99 based on the detection result from the encoder 991 to move the carriage 6 to the left from the ejection position B2 and stop it at the maintenance position B1. Then, the control unit 80 caps the head 30 with the cap of the maintenance unit. Thus, the flow shown in Figure 10 is completed.

[0063] As described above, in the printing apparatus 1 of this embodiment, humidified air supply ports 81a1, 81b1, 82a1, and 82b1 are provided around the platen 12 located at the printing position P3, making it possible to supply humidified air from the humidified air supply ports 81a1, 81b1, 82a1, and 82b1 to the support surface 12a of the platen 12. Therefore, when printing by ejecting ink from the nozzles of the head 30 onto a printing medium coated with a pretreatment liquid, it becomes possible to supply humidified air onto the printing medium. This makes it difficult for the volatile components of the pretreatment liquid coated on the printing medium to volatilize at the printing position P3, and also makes it difficult for the volatile components of the pretreatment liquid themselves to reach the nozzles. Thus, it is possible to suppress malfunctions caused by the reaction between the ink in the nozzle and the volatile components of the pretreatment liquid. Furthermore, as described above, it is possible to suppress malfunctions caused by the reaction between the ink in the nozzle and the volatile components of the pretreatment liquid, making it possible to use a pretreatment liquid containing organic acids as volatile components. Furthermore, it becomes possible to suppress the volatilization of organic acids in the pretreatment solution applied to the printing medium.

[0064] Furthermore, the humidified air supply ports 81a1, 81b1, 82a1, and 82b1 are arranged between a pair of inner walls 71 and 72 in the left-right direction. This makes it possible to effectively supply humidified air from the humidified air supply ports 81a1, 81b1, 82a1, and 82b1 to the support surface 12a of the platen 12 located at the printing position P3.

[0065] Furthermore, the humidified air supply ports 81a1, 81b1, 82a1, and 82b1 are positioned in the left-right direction so that the left and right ends of the platen 12, which is located at the printing position P3, are positioned between the humidified air supply ports 81a1, 81b1, 82a1, and 82b1 and the suction ports 713 and 723. As a result, the humidified air supplied from the humidified air supply ports 81a1, 81b1, 82a1, and 82b1 passes over the platen 12 before being drawn into the suction ports 713 and 723. Therefore, at the printing position P3, the volatile components of the pretreatment liquid applied to the printing medium are less likely to volatilize, and the volatile components of the pretreatment liquid themselves are less likely to reach the nozzle.

[0066] Furthermore, the humidified air supply ports 81a1, 81b1, 82a1, and 82b1 face the support surface 12a of the platen 12 located at the printing position P3. This makes it possible to supply humidified air toward the support surface 12a. As a result, at the printing position P3, the volatile components of the pretreatment liquid applied to the printing medium become less likely to volatilize, and the volatile components of the pretreatment liquid themselves become less likely to reach the nozzle.

[0067] Furthermore, the four humidified air supply ports 81a1, 81b1, 82a1, and 82b1 are positioned in a plan view, with two ports each corresponding to the center of the opposing front and rear edges of the support surface 12a of the platen 12 located at the printing position P3. This makes it possible to effectively supply humidified air to the support surface 12a of the platen 12. As a result, at the printing position P3, the volatile components of the pretreatment liquid applied to the printing medium are less likely to volatilize, and the volatile components of the pretreatment liquid themselves are less likely to reach the nozzle.

[0068] As a modified example, two or more humidifying air supply ports may be provided, and in a plan view, one or more ports may be arranged at positions corresponding to the center of the opposing front and rear edges of the support surface 12a of the platen 12 located at the printing position P3. Alternatively, the humidifying air supply ports may be arranged at positions corresponding to the center of the opposing left and right edges of the support surface 12a of the platen 12 located at the printing position P3 in a plan view.

[0069] Furthermore, the control unit 80 controls the humidifier 86 to generate humidified air and supply it from the humidified air supply ports 81a1, 81b1, 82a1, and 82b1 from the time a print start command is input until printing on the printing medium based on the print data is completed. As a result, humidified air is supplied to the printing medium before ink is ejected from the nozzle to the printing medium. Therefore, volatile components of the pretreatment liquid are less likely to evaporate at the time the ink is ejected, and the volatile components of the pretreatment liquid themselves are less likely to reach the nozzle. In addition, since humidified air is continuously supplied even when the platen 12 is positioned at the print position P3, volatile components of the pretreatment liquid are further less likely to evaporate when the printing medium and the nozzle are facing each other.

[0070] In the above-described embodiment, the four humidified air supply ports 81a1, 81b1, 82a1, and 82b1 were arranged in a plan view, with two ports each corresponding to the center of the opposing front and rear edges of the support surface 12a of the platen 12 located at the printing position P3. However, the humidified air supply ports may also be arranged at positions corresponding to the four corners of the support surface 12a. Components similar to those in the above-described embodiment are denoted by the same reference numerals and their descriptions are omitted.

[0071] In this modified example, the printing apparatus 201 has four humidified air supply pipes 281-284, as shown in Figure 11, which are fixed to the frame 2. These humidified air supply pipes 281-284 are made of straight pipes. The four humidified air supply pipes 281-284 are arranged around the platen 12 located at the printing position P3, with two of them, 281 and 282, positioned at the front and the other two, 283 and 284, positioned at the rear.

[0072] The four humidified air supply pipes 281-284 each have humidified air supply ports 281a-284a at one end, and piping (not shown) connected to supply ports 75 and 76 at the other end. More specifically, the piping connected to supply port 75 branches into two and connects to two humidified air supply pipes 281 and 283 located on the left side. The piping connected to supply port 76 branches into two and connects to two humidified air supply pipes 282 and 284 located on the right side.

[0073] Furthermore, the four humidifying air supply pipes 281-284 are positioned at an angle in the front-to-back and left-to-right directions such that the humidifying air supply ports 281a-284a face the support surface 12a of the platen 12 located at the printing position P3. Two of the humidifying air supply ports 281a and 282a face backward, while the two humidifying air supply ports 283a and 284a face forward. For example, the four humidifying air supply ports 281a-284a are positioned at the four corners of the support surface 12a of the platen 12 located at the printing position P3.

[0074] Furthermore, the four humidified air supply ports 281a to 284a are positioned at the same location in the vertical direction, as shown in Figure 12. More specifically, the four humidified air supply ports 281a to 284a are positioned above the platen 12 such that the distance from their central axis (the central axis passing through the center of the opening) to the support surface 12a of the platen 12 is a predetermined distance T2. The four humidified air supply ports 281a to 284a open toward the spatial area on the support surface 12a of the platen 12 located at the printing position P3 (the area between the head 30 and the support surface 12a in the vertical direction).

[0075] As shown in Figure 13, the humidified air supplied from these four humidified air supply ports 281a to 284a is supplied towards the platen 12 from near the four corners of the platen 12, which is located at the printing position P3, in a plan view. As a result, a large amount of humidified air is supplied to the rear region PA and the front region PB in the space between the platen 12 and the head 30. At this time, the suction mechanisms 73 and 74 are driven, causing the humidified air supplied to the rear region PA and the front region PB to flow outward along the left-right direction and be sucked in from the suction ports 713 and 723.

[0076] In this modified example of the printing apparatus 201, humidified air is supplied during printing, similar to the embodiment described above. Specifically, when a printing start command is input, the control unit 80 controls the humidifier 86 so that the supply of humidified air begins from the four humidified air supply ports 281a to 284a. As a result, humidified air is supplied to the spatial region including the rear region PA and the front region PB, as shown in Figure 13. At the same time, the control unit 80 also drives the fans 94 of the suction mechanisms 73 and 74. This creates a flow of humidified air that flows from the humidified air supply ports 281a to 284a through the rear region PA and the front region PB to the suction ports 713 and 723.

[0077] After this, the control unit 80 performs the same printing process as in the embodiment described above. In this modified example as well, humidified air is supplied from the four humidified air supply ports 281a to 284a before the printing process is performed, so that when printing is performed on the printing medium, humidified air is supplied to the printing medium. In other words, a layer of humidified air exists on the printing medium. As a result, the volatile components of the pretreatment liquid applied to the printing medium are less likely to volatilize. Furthermore, even if the volatile components of the pretreatment liquid volatilize, these volatile components are less likely to reach the nozzles of the head 30 that face the printing medium.

[0078] Then, when printing on the printing medium based on the print data is completed while the humidified air layer is present on the printing medium, the control unit 80 controls the humidifier 86 to stop supplying humidified air from the four humidified air supply ports 281a to 284a. At this time, the control unit 80 also stops driving the fans 94 of the suction mechanisms 73 and 74. In this way, the flow of humidified air from the humidified air supply ports 281a to 284a to the rear area PA and the front area PB, and from the rear area PA and the front area PB to the suction ports 713 and 723 is stopped.

[0079] Furthermore, the control unit 80 controls the sub-scanning motor 26 based on the detection result from the encoder 261 to stop the platen 12 at the support position P1. The user removes the printed medium with the image formed on it from the platen 12 positioned at the support position P1. At this time, the control unit 80 controls the main scanning motor 99 based on the detection result from the encoder 991 to move the carriage 6 to the left from the ejection position B2 and stop it at the maintenance position B1. Then, the control unit 80 caps the head 30 with the cap of the maintenance unit. In this way, the printing flow is completed.

[0080] As described above, the same effect can be obtained in the modified printing apparatus 201 with the same configuration as the embodiment described above. Furthermore, the four humidified air supply ports 281a to 284a are positioned in a plan view to correspond to the four corners of the support surface 12a of the platen 12 located at the printing position P3. This makes it possible to effectively supply humidified air to the support surface 12a of the platen 12. As a result, at the printing position P3, the volatile components of the pretreatment liquid applied to the printing medium become less likely to volatilize, and the volatile components of the pretreatment liquid themselves become less likely to reach the nozzle.

[0081] Furthermore, in the embodiments and modifications described above, a printing medium coated with a pretreatment solution was placed on the platen 12 and printing was performed on the printing medium. However, the printing apparatus 1,201 may have a pretreatment solution coating mechanism that coats the printing medium with a pretreatment solution containing the same volatile components as described above. Components similar to those in the embodiments described above are denoted by the same reference numerals and their descriptions are omitted.

[0082] In the modified printing apparatus 401, as shown in Figure 14, the pretreatment liquid application mechanism 402 is positioned between the support position P1 and the printing position P3 in the front-rear direction. The pretreatment liquid application mechanism 402 is also located inside the housing 8 and above the support surface 12a of the platen 12. The pretreatment liquid application mechanism 402 has a plurality of nozzles 403 that spray the pretreatment liquid in a mist downwards. The plurality of nozzles 403 are arranged in a line along the left-right direction so that the pretreatment liquid can be sprayed onto the entire upper surface of the printing medium. The printing apparatus 401 is also provided with a storage section (not shown) capable of storing the pretreatment liquid, and the pretreatment liquid is supplied from this storage section to the pretreatment liquid application mechanism 402.

[0083] In the printing apparatus 401 in this modified example, when printing is performed, there is a pretreatment liquid application mechanism 402, so the user places the printing medium (T-shirt) which has not been pre-treated with pretreatment liquid, on the support surface 12a of the platen 12 before operating the operation unit 15 and inputting a print start command. In this modified example as well, the platen 12 is positioned at the support position P1 when not printing.

[0084] After this, when a print start command is input, the control unit 80 controls the sub-scanning motor 26 based on the detection result from the encoder 261 to move the platen 12 from the support position P1 to the pre-print standby position P2. At this time, the control unit 80 controls the pre-treatment liquid application mechanism 402 so that the pre-treatment liquid is sprayed in a mist onto the printing medium as the printing medium passes through the area facing the multiple nozzles 403. This allows the pre-treatment liquid to be applied to the upper surface of the printing medium.

[0085] Next, the control unit 80 controls the humidifier 86 to supply humidified air, similar to the embodiments and modifications described above. At this time, the control unit 80 also drives the fans 94 of the suction mechanisms 73 and 74. After this, the control unit 80 performs the printing process, similar to the embodiments and modifications described above.

[0086] After this, when printing on the printing medium based on the print data is completed while the humidified air layer is present on the printing medium, the control unit 80 controls the humidifier 86 to stop supplying humidified air. At this time, the control unit 80 also stops driving the fans 94 of the suction mechanisms 73 and 74. The control unit 80 also controls the sub-scanning motor 26 based on the detection result from the encoder 261 to stop the platen 12 at the support position P1. The user removes the printing medium with the image formed on it from the platen 12 positioned at the support position P1. At this time, the control unit 80 also controls the main scanning motor 99 based on the detection result from the encoder 991 to move the carriage 6 to the left from the ejection position B2 and stop it at the maintenance position B1. Then, the control unit 80 caps the head 30 with the cap of the maintenance unit. Thus, the printing flow is completed.

[0087] As described above, the printing apparatus 401 in this modified example has a pretreatment liquid application mechanism 402, which enables the application of pretreatment liquid to the printing medium. Therefore, it is not necessary to apply pretreatment liquid to the printing medium in advance. Furthermore, the pretreatment liquid application mechanism 402 is configured to spray the pretreatment liquid onto the printing medium in a mist. This makes it possible to apply a large amount of pretreatment liquid to a wide area of ​​the printing medium in a short time. Applying a large amount of pretreatment liquid to the printing medium in a short time increases the amount of volatile components of the pretreatment liquid from the printing medium. Even under these circumstances, since humidified air can be supplied as described above, it is possible to effectively suppress problems caused by the reaction between the ink in the nozzle and the volatile components of the pretreatment liquid. The pretreatment liquid application mechanism 402 is not particularly limited as long as it is capable of applying pretreatment liquid to the printing medium. For example, the pretreatment liquid may be applied to the printing medium with a roller, or the pretreatment liquid may be discharged from a nozzle in a manner other than mist and applied to the printing medium. The same effects can be obtained in the printing apparatus 401 of this modified example if it has the same configuration as the embodiment and modified example described above.

[0088] Although preferred embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications are possible as long as they are within the scope of the claims.

[0089] In the embodiments and their respective modifications described above, the supply of humidified air is started between the input of a print start command and the ejection of ink from the nozzles of the head 30. However, the supply of humidified air may also be started between the ejection of ink from the nozzles of the head 30 and the completion of printing. In this case as well, it is possible to suppress malfunctions caused by the reaction between the ink in the nozzles and the volatile components of the pretreatment liquid. Furthermore, the supply of humidified air may be continued while the power of the printing device is ON. Also, in the embodiments and their respective modifications described above, the supply of humidified air is performed continuously from the input of a print start command until the completion of printing, but it may be performed intermittently. Furthermore, regardless of the position of the head 30, humidified air may be supplied only when the platen 12 is positioned at the printing position P3, or humidified air may be supplied only when the head 30 and the platen 12 are facing each other.

[0090] Furthermore, in the embodiments and modifications described above, humidified air was supplied by connecting the supply ports 75, 76 and the humidified air supply pipes 81, 82, 281-284 with piping. However, humidifier 86 may be connected to humidified air supply pipes 81, 82, 281-284 with piping to supply humidified air to the space above the platen 12 located at the printing position P3. In this case, humidified air may be supplied into the housing 8 from the supply ports 75, 76 (the "humidified air supply ports" of the present invention) provided around the platen 12 located at the printing position P3, and the humidified air may be supplied to the space between the platen 12 and the head 30 by the airflow from the exhaust of the fan 94 and the suction force of the air inside the housing 8 by the suction ports 713, 723. This effectively suppresses malfunctions caused by the reaction between the ink in the nozzle and the volatile components of the pretreatment liquid.

[0091] Furthermore, the humidified air supply ports 81a1, 81b1, 82a1, 82b1, 281a~284a may open so that their central axes face the support surface 12a of the platen 12 located at the printing position P3. Also, the humidified air supply ports 81a1, 81b1, 82a1, 82b1, 281a~284a may be located below the support surface 12a of the platen 12 in the vertical direction. In this case, it is desirable that they open toward the spatial area above the support surface 12a of the platen 12 located at the printing position P3. In addition, one or more humidified air supply ports are provided around the platen 12 located at the printing position P3, and it is sufficient that they supply humidified air to the support surface 12a of the platen 12.

[0092] Furthermore, the number of fans 94 described above may be between 1 and 2, or between 4 and 4. Also, the fans 94 and the suction ports 713 and 723 may not be provided. In addition, the printing apparatus 1,201,401 may not have a humidifier 86; in this case, humidified air generated externally may be sent to the humidified air supply port via piping or the like.

[0093] Furthermore, in the above-described embodiment, the platen 12 moves along the sub-scanning direction (front-to-back direction) together with the printing medium by the transport mechanism 14, but the platen 12 may be positioned so as not to move at the printing position P3. In this case, the platen 12 only needs to be able to support the transported printing medium (e.g., paper or roll paper) at the printing position P3.

[0094] Furthermore, although the above-described embodiment describes an example in which the present invention is applied to a printing apparatus equipped with a so-called serial head, in which the head 30 moves along the main scanning direction (left-right direction) by a moving mechanism 77 and ejects ink from multiple nozzles, the present invention is not limited to this. For example, the present invention can also be applied to a printing apparatus equipped with a line head that extends along the entire length of the printing medium (platen 12) in the main scanning direction and is immovably positioned at the ejection position B2.

[0095] Furthermore, in the above-described embodiments and their respective modifications, the control unit 80 may use a microcomputer, ASIC (Application Specific Integrated Circuits), FPGA (Field Programmable Gate Array), etc., as the processor instead of the CPU 80a. In this case, the main processing may be distributed among multiple processors. Non-temporary storage media such as ROM 80b and flash memory 80d may be any storage medium capable of retaining information regardless of the period for which the information is stored. Non-temporary storage media do not necessarily have to include temporary storage media (e.g., transmitted signals). The control program may be downloaded from, for example, a server connected to a network (not shown) (i.e., transmitted as a transmission signal) and stored in ROM 80b or flash memory 80d. In this case, the control program only needs to be stored in a non-temporary storage medium such as an HDD provided in the server. In the above-described embodiments and their respective modifications, the volatile components of the pre-treatment liquid include organic acids, but are not limited to these. That is, the volatile components of the pre-treatment liquid may include components other than organic acids that react with the ink in the nozzle to cause aggregation or discoloration. [Explanation of Symbols]

[0096] 1,201,401 Printing equipment 12 Platen 12a Support surface 14. Conveying mechanism (moving mechanism) 30 (31-34) head 71,72 Inner wall 80 Control Unit 81a1, 81b1, 82a1, 82b1, 281a~284a Humidifying air supply port 86 Humidifier (Humidifying Air Generator) 94 Fans 402 Pretreatment liquid application mechanism 313,323,333,343 nozzles 713,723 Suction port

Claims

1. A head having a nozzle for ejecting ink, A platen having a support surface capable of supporting a printing medium coated with a pretreatment solution containing volatile components that react with ink, A humidified air supply port is provided around the platen, which is positioned at a printing location facing the nozzle, and supplies humidified air to the support surface of the platen that supports the printing medium, A pair of interior walls, spaced apart from each other and both extending in one direction, Between the pair of inner walls, the device includes a moving mechanism for moving the platen in one direction between the printing position and a support position different from the printing position, which supports the printing medium on the platen. The humidifying air supply port is positioned between the pair of inner walls in a direction perpendicular to the aforementioned one direction. Fans, The system further includes an intake port provided along the inner wall, through which air is drawn in by the fan, The printing apparatus is characterized in that the humidifying air supply port is positioned in the orthogonal direction between the humidifying air supply port and the suction port, at a position in which at least a portion of the platen positioned at the printing location is positioned.

2. The printing apparatus according to claim 1, characterized in that the humidifying air supply port faces the support surface side.

3. A head having a nozzle for ejecting ink, A platen having a support surface capable of supporting a printing medium coated with a pretreatment solution containing volatile components that react with ink, The platen, which is positioned at a printing location where the support surface faces the nozzle, is provided with a humidified air supply port that supplies humidified air to the support surface of the platen that supports the printing medium. The support surface has a square shape, At least four of the aforementioned humidifying air supply ports are provided. The printing apparatus is characterized in that the four humidifying air supply ports are arranged in positions corresponding to the four corners of the support surface in a plan view.

4. A head having a nozzle for ejecting ink, A platen having a support surface capable of supporting a printing medium coated with a pretreatment solution containing volatile components that react with ink, The platen, which is positioned at a printing location where the support surface faces the nozzle, is provided with a humidified air supply port that supplies humidified air to the support surface of the platen that supports the printing medium. The support surface has a square shape, At least two of the aforementioned humidifying air supply ports are provided. The printing apparatus is characterized in that the two humidifying air supply ports are positioned in a plan view, corresponding to the center of two opposing sides of the support surface.

5. A humidified air generating unit that generates humidified air, It further includes a control unit, The printing apparatus according to any one of claims 1 to 4, characterized in that the control unit controls the humidified air generation unit to generate humidified air and supply the humidified air from the humidified air supply port between the time a print start command is input to discharge ink from the nozzle and print on the printing medium and the time ink is discharged from the nozzle.

6. The printing apparatus according to claim 5, characterized in that the control unit controls the humidified air generating unit to supply humidified air from the humidified air supply port when the platen is positioned at the printing position.

7. The printing apparatus according to any one of claims 1 to 6, further comprising a pretreatment liquid application mechanism for applying the pretreatment liquid to a printing medium.

8. The printing apparatus according to claim 7, characterized in that the pretreatment liquid application mechanism is configured to spray the pretreatment liquid onto the printing medium in a mist.

9. The printing apparatus according to any one of claims 1 to 8, characterized in that the pretreatment liquid contains an organic acid as a volatile component.

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