Printing apparatus

Abstract

To provide a printing apparatus that can suppress the increase in costs related to the suction of printing media. [Solution] The printing apparatus comprises a transport unit that transports the printing medium in the transport direction, a support unit that supports the printing medium while sucking it through a plurality of suction holes, and a print head positioned opposite the support unit and ejecting ink onto the printing medium supported by the support unit to print. The support unit comprises a support plate in which suction holes are formed, a first negative pressure chamber provided on the opposite side of the support plate from the print head, a second negative pressure chamber provided on the opposite side of the support plate from the print head and positioned downstream of the first negative pressure chamber in the transport direction, a first fan that sucks gas from the first negative pressure chamber which is connected to the suction holes, and a second fan that sucks gas from the second negative pressure chamber which is connected to the suction holes. The suction pressure in the region of the support plate corresponding to the first negative pressure chamber is greater than the suction pressure in the region of the support plate corresponding to the second negative pressure chamber.

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a printing apparatus and a printing method that suppress displacement of ink landing positions. In this printing apparatus, a support section sucks a print medium through a plurality of suction holes arranged in the conveyance direction of the print medium, a line-type print head ejects ink onto the print medium being moved over the support section by a conveyance section, and an ejection timing control section sets, when a leading end of the print medium in the conveyance direction is located in a first region of the support section, the ejection timing as a first ejection timing, and when the leading end is located in a second region of the support section which is located downstream of the first region in the conveyance direction, the ejection timing as a second ejection timing, controls the ejection timing such that the first ejection timing is earlier than the second ejection timing. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2024-115642 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] In a printing apparatus like that of Patent Document 1, depending on the dimensions of the print medium and the support section, the suction pressure for sucking the print medium may be uneven, and there is a risk that the suction pressure necessary for holding the print medium cannot be obtained at a predetermined position. For this reason, in such a printing apparatus, the number of fans for sucking the print medium increases, and there is a risk that the cost associated with sucking the print medium increases. [Means for Solving the Problem]

[0005] One embodiment for solving the above problem is a printing apparatus comprising: a transport unit for transporting a printing medium in a transport direction; a support unit for supporting the printing medium while sucking it through a plurality of suction holes; and a print head positioned opposite the support unit for printing by ejecting ink onto the printing medium supported by the support unit, wherein the support unit comprises: a support plate in which the suction holes are formed; a first negative pressure chamber provided on the opposite side of the support plate from the print head; a second negative pressure chamber provided on the opposite side of the support plate from the print head and positioned downstream of the first negative pressure chamber in the transport direction; a first fan communicating with the suction holes for sucking gas from the first negative pressure chamber; and a second fan communicating with the suction holes for sucking gas from the second negative pressure chamber, wherein the suction pressure in the region of the support plate corresponding to the first negative pressure chamber is greater than the suction pressure in the region of the support plate corresponding to the second negative pressure chamber. [Brief explanation of the drawing]

[0006] [Figure 1] A schematic side view showing the internal structure of a printing apparatus according to an embodiment of this disclosure. [Figure 2] A schematic plan view showing the internal structure of a printing device. [Figure 3] A diagram showing the suction pressure at each of the suction holes of the printing device. [Modes for carrying out the invention]

[0007] Embodiments of this disclosure will be described below with reference to the drawings. In each figure, the symbol FR indicates the front of the printing device 1 when it is installed on the mounting surface and in its normal operating state, the symbol UP indicates the top of the printing device 1, and the symbol LH indicates the left side of the printing device. The front-to-back and left-to-right directions of the printing device 1 coincide with the horizontal direction, and the up-to-down direction coincides with the vertical direction. In the following description, each direction refers to the direction of the printing device 1.

[0008] [Printing device configuration] Figure 1 is a schematic side view showing the internal structure of a printing apparatus 1 according to an embodiment of this disclosure. In Figure 1, for the sake of explanation, the transport direction C is shown by a dashed line, and the printing medium 100 is shown by a double dashed line. The printing device 1 shown in Figure 1 is a line-type inkjet printer equipped with a line-shaped inkjet head that ejects ink from the inkjet head to print characters and images on a printing medium 100 that is transported along the transport direction C. In the following description, the transport direction C is the direction perpendicular to the left-right direction in the printing device 1, moving from rear to front.

[0009] The printing medium 100 used for printing in the printing apparatus 1 is a cut sheet or continuous sheet cut to a predetermined size. These sheets are made of paper, synthetic resin, or the like. These sheets may be, for example, fine paper that has been treated to enhance ink absorption and fixation, making it suitable for inkjet printing.

[0010] Examples of continuous sheets include roll paper that is stored in the printing device 1 in a roll-like state, and fanfold paper that is supplied to the printing device 1 from outside the printing device 1 in a folded state. As for roll paper, in addition to paper made by rolling up plain paper or fine paper, label paper may also be used, in which standard-sized labels with adhesive on the back are arranged on a release paper backing and rolled up.

[0011] The printing device 1 includes a printing unit 22 for printing on a printing medium 100. The printing unit 22 includes a print head 42. In this embodiment, the print head 42 sprays four colors of ink: C (cyan), M (magenta), Y (yellow), and K (black) to form dots on the printing surface of the label. The print head 42 includes a nozzle unit 41 for spraying K (black) ink, a nozzle unit 43 for spraying C (cyan) ink, a nozzle unit 45 for spraying M (magenta) ink, and a nozzle unit 47 for spraying Y (yellow) ink. Multiple nozzles for spraying ink are arranged in rows in the width direction of the printing medium 100 in nozzle units 41 to 47. The nozzles in each nozzle unit 41 to 47 are arranged in a direction that intersects the transport direction C.

[0012] The print head 42 is a line inkjet head capable of ejecting ink in the width direction of the printing medium 100 without scanning. Therefore, the nozzle rows of nozzle sections 41 to 47 are formed to have a width at least the same as, or wider than, the printable area of ​​the printing medium 100. In this embodiment, the printable area corresponds to the printable surface of the label. In this embodiment, an example configuration is given in which nozzles 41, 43, 45, and 47 are arranged in that order along the transport direction C of the printing medium 100, but the arrangement order of the nozzles of each color in the transport direction C is arbitrary.

[0013] In the printing apparatus 1, a support section 30 is provided below the printing section 22. The support section 30 comprises a box-shaped support housing 32 with an internal space R, and a flat platen 40 is formed on its upper surface. The platen 40 is located below the transported printing medium 100 and faces the print head 42. The nozzle sections 41-47 and the platen 40 are spaced apart, a gap known as the platen gap. The platen 40 supports the printing medium 100 from below. The platen 40 is provided over at least the entire printing area of ​​the printing section 22. The plane of the platen 40 is positioned approximately horizontally when the printing device 1 is installed and in use.

[0014] A conveying section 24 is provided at the rear end of the support section 30. The conveying section 24 is equipped with cylindrical conveying rollers 50. The conveying rollers 50 are arranged so as to extend along a direction perpendicular to the conveying direction C in their longitudinal direction and are rotatable in the circumferential direction. The conveying rollers 50 are positioned at the rear end of the platen 40. A conveying motor, which is a drive device for rotating the conveying rollers 50, is attached to the conveying rollers 50.

[0015] The transport unit 24 is equipped with a plurality of paper feed driven rollers 54. The paper feed driven rollers 54 are rotatably arranged along the longitudinal direction of the transport roller 50. Each of the paper feed driven rollers 54 is biased so that its circumferential surface contacts the circumferential surface of the transport roller 50. As a result, the transport roller 50 and the paper feed driven rollers 54 are positioned opposite each other.

[0016] In the transport unit 24, the transport motor drives the transport roller 50 to rotate, and the paper feed driven roller 54 is driven to rotate as well. The printing medium 100 is sandwiched between the transport roller 50 and the paper feed driven roller 54 and is transported between the printing unit 22 and the support unit 30 as the transport roller 50 rotates. The printing medium 100 is transported to the printing unit 22, where it is printed. After this, the printing medium 100 is discharged to the outside of the printing device 1 by the drive of the transport unit 24.

[0017] [Support structure] In the support section 30, the bottom of the support section housing 32 is provided with a first ventilation opening 31 and a second ventilation opening 33, which are openings that connect the inside and outside of the support section housing 32. The first ventilation opening 31 and the second ventilation opening 33 are arranged side by side along the transport direction C, and the first ventilation opening 31 is located upstream of the second ventilation opening 33 in the transport direction C. In this embodiment, both the first ventilation opening 31 and the second ventilation opening 33 are positioned approximately in the center of the support section housing 32 in the left-right direction.

[0018] The first ventilation opening 31 is covered by the first fan 60 from the outside of the support housing 32. The second ventilation opening 33 is covered by the second fan 62 from the outside of the support housing 32. The first fan 60 is a blower that, when driven, sucks air from the space R of the support housing 32 through the first ventilation opening 31 and blows the air out to the outside. The second fan 62 is a blower that, when driven, sucks air from the space R of the support housing 32 through the second ventilation opening 33 and blows the air out to the outside. Various blowers such as axial fans and centrifugal fans may be used as the first fan 60 and the second fan 62.

[0019] In the present embodiment, the first fan 60 and the second fan 62 have substantially the same performance. Specifically, both the first fan 60 and the second fan 62 have substantially the same airflow-static pressure characteristics. Therefore, in the printing apparatus 1, substantially the same blower can be used regardless of the arrangement position. Therefore, in the printing apparatus 1, an increase in cost for holding a print medium can be suppressed.

[0020] Figure 2 is a plan view schematically showing the internal structure of the printing apparatus 1. In Figure 2, for convenience of explanation, the conveyance direction C is indicated by an alternate long and short dash line, and the print medium 100 is indicated by an alternate long and two short dashes line. As shown in Figure 2, the platen 40 is provided with a plurality of first suction holes 46 and a plurality of second suction holes 48. Both the plurality of first suction holes 46 and the plurality of second suction holes 48 are through holes penetrating in the plate thickness direction. In the present embodiment, in plan view, the opening area of each first suction hole 46 is formed to be larger than the opening area of each second suction hole 48.

[0021] In the printing apparatus 1, when the first fan 60 and the second fan 62 are rotationally driven, air in the space R of the support housing 32 is sucked out, and further, air outside the support housing 32 is sucked into the interior through the plurality of first suction holes 46 and the plurality of second suction holes 48. As a result, the printing medium 100 being transported by the transport unit 24 is attracted to the platen 40 and held in place so as not to separate from the platen 40 while being transported. Therefore, the printing unit 22 can perform printing while suppressing a decrease in printing accuracy.

[0022] In a plan view of the platen 40, each of the first suction holes 46 is positioned adjacent to the conveyor roller 50, with a predetermined distance between them and a predetermined distance from the edge of the platen 40. In the platen 40, each of the second suction holes 48 is positioned in a line with a predetermined distance between them, in front of the area where the first suction holes 46 are arranged, in other words, downstream in the conveying direction, and also at a predetermined distance from the edge of the platen 40. In the following explanation, the region where the first suction holes 46 are arranged will be referred to as the attraction region A1, and the region where the second suction holes 48 are arranged will be referred to as the holding region A2.

[0023] In the attraction region A1, the printing medium 100, which is transported by the transport unit 24, is attracted to the platen 40. As a result, in the platen 40, in the attraction region A1, the air from outside the support housing 32 is drawn in through the first suction hole 46 with a greater suction pressure, or in other words, a greater static pressure, than in other regions, i.e., the holding region A2.

[0024] The sum of the opening areas S1 of the first suction holes 44 in the attraction region A1 is expressed by the following equation (1). S1≦Q1 / (√(2×P1 / ρ1))···(1) In equation (1), Q1 is the airflow rate output by the first fan 60 when it outputs the static pressure necessary to attract the printing medium 100, which is being transported by the transport unit 24, to the platen 40 in the attraction region A1. This airflow rate can be determined from the static pressure-airflow characteristics provided by the fan manufacturer, etc., based on the static pressure of the fan. P1 is the static pressure necessary to attract the printing medium 100, which is being transported by the transport unit 24, to the platen 40, and is a value obtained by conducting experiments in advance. ρ1 is the density of the air drawn into the first fan 60.

[0025] The platen 40 has first suction holes 46, each with an opening area that satisfies the total value S1 calculated by Equation 1, and an attraction region A1. In this embodiment, each of the first suction holes 46 is formed in a circular shape with a diameter of 4.0 mm in plan view. Each of the first suction holes 46 is arranged on the platen 40 at equal intervals, with a distance of 9 mm or less between them.

[0026] In the attraction region A1, the printing medium 100, which is transported by the transport unit 24, is attracted to the platen 40. As a result, in the platen 40, in the attraction region A1, air from outside the support housing 32 is drawn in through the first suction hole 46 at a higher suction pressure, or in other words, a higher static pressure, than in other regions, i.e., the holding region A2.

[0027] The suction pressure in the attraction region A1 is equal to or greater than the suction pressure required to attract the printing medium 100 when the entire attraction region A1 is covered by the printing medium 100 in a plan view, based on the total value S1 described above and the airflow output by the first fan 60. This allows the printing apparatus 1 to attract and hold each of the printing media 100 that can be placed on the platen 40.

[0028] The sum of the opening areas S2 of each of the second suction holes 48 in the holding region A2 is expressed by equation (1) in the same way as the sum S2. S2≦Q / (√(2×P / ρ))···(1) The sum of the opening areas of each of the second suction holes 48 in the holding region A2, S2, is expressed by the following equation (2), similar to the sum S1. S2≦Q2 / (√(2×P2 / ρ2))···(2) In equation (2), Q2 is the airflow rate output by the second fan 62 when it outputs the static pressure necessary to hold the printing medium 100, which is being transported by the transport unit 24, on the platen 40 in the holding area A2. This airflow rate can be determined from the static pressure-airflow characteristics provided by the fan manufacturer or the like, based on the static pressure of the fan. P2 is the static pressure necessary to hold the printing medium 100, which is being transported by the transport unit 24, on the platen 40, and is a value obtained through experiments conducted in advance. ρ2 is the density of the air drawn into the second fan 62.

[0029] The platen 40 has a holding region A2 and each of the second suction holes 48 having an opening area that satisfies the total value S2 calculated by Equation 1. In this embodiment, the second suction holes 48 are formed in a circular shape with a diameter of 1.5 mm in plan view, and each of the second suction holes 48 is arranged on the platen 40 at equal intervals, with a distance of 9 mm or less between them.

[0030] The suction pressure in the holding area A2 is equal to or greater than the suction pressure that can attract the printing medium 100 when the entire holding area A2 is covered by the printing medium 100 in a plan view, based on the total value S2 described above and the airflow output by the second fan 62. This allows the printing apparatus 1 to attract and hold each of the printing media 100 that can be placed on the platen 40.

[0031] As shown in Figures 1 and 2, the support housing 32 is provided with a partition member 38 that divides the internal space R. The partition member 38 is formed in a plate shape, with its planes facing each other in the front-to-back direction. The upper end of the partition member 38 is connected to the platen 40, and the lower end is connected to the bottom of the support housing 32. Each of the left and right ends of the partition member 38 is connected to the left and right sides of the support housing 32. In this way, the partition member 38 divides the space R into front-to-back sections. In other words, the partition member 38 divides the space R into an upstream side and a downstream side in the transport direction C. In the following explanation, the space partitioned by the partition member 38 and located upstream in the transport direction C is referred to as the pull space R1, and the space partitioned by the partition member 38 and located downstream in the transport direction C is referred to as the holding space R2.

[0032] In a plan view of the platen 40, the upper end of the partition member 38 is positioned between the pull-in area A1 and the holding area A2. In a plan view of the platen 40, the lower end of the partition member 38 is positioned between the first ventilation opening 31 and the second ventilation opening 33. As a result, each of the first suction holes 46 and the first ventilation opening 31 are connected to the attraction space R1, and each of the second suction holes 48 and the second ventilation opening 33 are connected to the holding space R2.

[0033] As shown in Figure 1, a shutter mechanism 70 is provided in both the pull-in space R1 and the holding space R2. Each of the shutter mechanisms 70 opens and closes at least a portion of the first suction hole 46 and the second suction hole 48 when driven. In this embodiment, each of the shutter mechanisms 70 is provided across the entire left-right direction of the platen 40. Each of the shutter mechanisms 70 can open and close the first suction hole 46 and the second suction hole 48 sequentially from right to left at the position in which the shutter mechanism 70 is provided. However, the shutter mechanism 70 is not limited to this, and each of the shutter mechanisms 70 may be capable of opening and closing the first suction hole 46 and the second suction hole 48 in order from both ends on the left and right sides toward approximately the center in the left-right direction at the position where the shutter mechanism 70 is installed.

[0034] [Printer operation] Figure 3 shows the relationship between the position of the leading edge of the printing medium 100 on the platen 40 and the suction pressure at the first suction hole 46 and the second suction hole 48, respectively. In Figure 2, the horizontal axis X indicates the position of the leading edge of the printing medium 100. On the horizontal axis X, the origin corresponds to the position of the downstream end of the platen 40, and as you move away from the origin, you approach the transport unit 24. The vertical axis Y indicates the suction pressure at the first suction hole 46 and the second suction hole 48, respectively. In Figure 3, point P1 indicates the position where the upper end of the partition member 38 is connected to the platen 40 between the attraction region A1 and the holding region A2. The downward-sloping shaded area indicates the suction pressure required to attract the printing medium 100 to the platen 40 in the attraction region A1, and point T1 indicates that value. The upward-sloping shaded area indicates the suction pressure required to hold the printing medium 100, which has been attracted to the platen 40, in the holding region A2, and point T2 indicates that value. In Figure 3, the suction pressure of the first suction hole 46, which changes as the printing medium 100 is transported, is shown by the solid line L1, and the suction pressure of the second suction hole 48, which changes as the printing medium 100 is transported, is shown by the dashed line L2.

[0035] When the printing medium 100 is transported to the printing unit 22, it is printed by the printing unit 22. In this case, the printing medium 100 is attracted to the platen 40 by being sucked into the first suction hole 46, and is held on the platen 40 by being sucked into the second suction hole 48. As shown in Figure 3, a higher suction pressure is required in the attraction region A1 than in the holding region A2.

[0036] In this embodiment, the support housing 32 is provided with a partition member 38 that divides the internal space R. As a result, the first fan 60 draws air from each of the first suction holes 46. Therefore, as shown in Figure 3, the suction pressure required to draw the printing medium 100 to the platen 40 can be obtained in the attraction region A1.

[0037] Similarly, the second fan 62 draws air from each of the second suction holes 48. As a result, as shown in Figure 3, the holding area A2 can obtain the suction pressure necessary to hold the printing medium 100 on the platen 40.

[0038] As a result, the printing device 1 can attract and hold the printing medium 100 without excessively increasing the performance or number of blowers. Therefore, the printing device 1 can improve printing accuracy while suppressing the increase in costs for holding the printing medium 100.

[0039] The embodiments described above are illustrative of one aspect of the present disclosure and can be modified and applied at will without departing from the spirit of the present disclosure.

[0040] In the embodiment described above, the first suction hole 46 is provided in the attraction region A1, and the second suction hole 48 is provided in the holding region A2. However, the invention is not limited to this configuration, and a portion of the second suction hole 48 may be located in the attraction region A1, as long as equations (1) and (2) are satisfied.

[0041] In the embodiment described above, the platen 40 is assumed to form the upper surface of the support housing 32. However, the platen 40 is not limited to this and may be formed in any way as long as the space communicating with the attraction region A1 and the space communicating with the holding region A2 are different spaces. For example, the platen 40 may be formed on the upper surfaces of the first housing, which is provided with a space communicating with the attraction region A1, and the second housing, which is provided with a space communicating with the holding region A2. Furthermore, in the above-described embodiment, the first fan 60 and the second fan 62 were assumed to have substantially the same performance. However, the invention is not limited to this, and fans with different performances may be used, as long as they satisfy the suction pressure required to attract the printing medium 100 transported by the transport unit 24 to the platen 40, and the suction pressure required to hold the printing medium 100 that has been attracted to the platen 40 in place.

[0042] In the embodiments described above, unless otherwise specified, the directions such as horizontal and vertical, numerical values, and various shapes include an equal range that produces the same effect as those directions, numerical values, and shapes.

[0043] [Summary of this disclosure] A summary of this disclosure is provided below.

[0044] (Note 1) A printing apparatus comprising: a transport unit for transporting a printing medium in a transport direction; a support unit for supporting the printing medium while sucking it through a plurality of suction holes; and a print head positioned opposite the support unit for printing by ejecting ink onto the printing medium supported by the support unit, wherein the support unit comprises: a support plate in which the suction holes are formed; a first negative pressure chamber provided on the opposite side of the support plate from the print head; a second negative pressure chamber provided on the opposite side of the support plate from the print head and positioned downstream of the first negative pressure chamber in the transport direction; a first fan communicating with the suction holes for sucking gas from the first negative pressure chamber; and a second fan communicating with the suction holes for sucking gas from the second negative pressure chamber, wherein the suction pressure in the region of the support plate corresponding to the first negative pressure chamber is greater than the suction pressure in the region of the support plate corresponding to the second negative pressure chamber. This allows the printing apparatus to attract and hold the printing medium without excessively increasing the performance or number of blowers. Therefore, the printing apparatus can improve printing accuracy while suppressing the increase in costs associated with holding the printing medium.

[0045] (Note 2) The printing apparatus according to Technology 1, wherein the suction pressure in the region of the support plate corresponding to the first negative pressure chamber is greater than or equal to the pressure at which the printing medium with the largest width dimension in a direction intersecting the transport direction reaches the region of the support plate among the printing media that the support plate can support, and the printing medium is attracted to the support plate. This allows printing equipment to improve printing accuracy while suppressing the increase in costs associated with holding the printing medium.

[0046] (Note 3) The printing apparatus according to Technology 1 or Technology 2, wherein the suction pressure in the region of the support plate corresponding to the second negative pressure chamber is equal to or greater than the pressure at which the printing medium with the largest width dimension in a direction intersecting the transport direction among the printing media that the support plate can support reaches the region of the support plate and is held by the support plate. This allows the printing apparatus to attract and hold each of the printing media that can be placed on the platen.

[0047] (Note 4) A printing apparatus according to any one of the three technologies described in Technology 1 to Technology 3, where S is the opening area of ​​the plurality of suction holes in the region of the support plate corresponding to the first negative pressure chamber, Q1 is the airflow rate of the first fan, P1 is the static pressure of the first fan, and ρ1 is the density of the gas drawn into the first fan, and the following formula (1) is satisfied. S1≦Q1 / (√(2×P1 / ρ1))···(1) This allows printing equipment to improve printing accuracy while suppressing the increase in costs associated with holding the printing medium. This allows printing equipment to improve printing accuracy while suppressing the increase in costs associated with holding the printing medium.

[0048] (Note 5) A printing apparatus according to any one of the following technologies 1 to 4, where S is the opening area of ​​the plurality of suction holes in the region of the support plate corresponding to the second negative pressure chamber, Q2 is the airflow rate of the first fan, P2 is the static pressure of the second fan, and ρ2 is the density of the gas drawn into the first fan, and the following equation (2) is satisfied. S2≦Q2 / (√(2×P2 / ρ2))···(2) This allows printing equipment to improve printing accuracy while suppressing the increase in costs associated with holding the printing medium.

[0049] (Note 6) The printing apparatus according to any one of the technologies 1 to 5, wherein the first fan and the second fan have substantially the same suction capacity. This allows printing equipment to improve printing accuracy while suppressing the increase in costs associated with holding the printing medium. [Explanation of Symbols]

[0050] 1…Printing device, 22…Printing section, 24…Conveying section, 30…Support section, 31…First ventilation opening, 32…Support section housing, 33…Second ventilation opening, 38…Partition member, 40…Platen, 41…Nozzle section, 42…Printing head, 43…Nozzle section, 44…First suction hole, 45…Nozzle section, 46…First suction hole, 47…Nozzle section, 48…Second suction hole, 50…Conveying roller, 54…Driven roller, 60…First fan, 62…Second fan, 70…Shutter mechanism, 100…Printing medium, A1…Attraction area, A2…Holding area, C…Conveying direction, P…Static pressure, Q…Air volume, R…Space, R1…Attraction space, R2…Holding space, S1…Total value, S2…Total value, ρ…Air density.

Claims

1. A transport unit that transports the printing medium, A support section that supports the printing medium while sucking it through multiple suction holes, A print head is positioned opposite the support portion and ejects ink onto the printing medium supported by the support portion to print, Equipped with, The aforementioned support portion is A support plate in which the suction holes are formed, A first negative pressure chamber is provided on the opposite side of the print head, sandwiching the support plate, A second negative pressure chamber is provided on the opposite side of the print head, sandwiching the support plate, and is located downstream of the first negative pressure chamber in the transport direction of the printing medium. A first fan that draws gas from the first negative pressure chamber, which is connected to the suction hole, A second fan that draws gas from the second negative pressure chamber, which is connected to the aforementioned suction hole, Equipped with, The suction pressure in the region of the support plate corresponding to the first negative pressure chamber is greater than the suction pressure in the region of the support plate corresponding to the second negative pressure chamber. Printing device.

2. The suction pressure in the region of the support plate corresponding to the first negative pressure chamber is greater than or equal to the pressure at which the printing medium with the largest width dimension in a direction intersecting the transport direction reaches the region of the support plate and is attracted to the support plate. The printing apparatus according to claim 1.

3. The suction pressure in the region of the support plate corresponding to the second negative pressure chamber is equal to or greater than the pressure required to hold the printing medium in the support plate when the printing medium with the largest width dimension in a direction intersecting the transport direction reaches the region of the support plate. The printing apparatus according to claim 2.

4. When S is the opening area of ​​the plurality of suction holes in the region of the support plate corresponding to the first negative pressure chamber, Q1 is the airflow rate of the first fan, P1 is the static pressure of the first fan, and ρ1 is the density of the gas drawn into the first fan, then the following equation (1) is satisfied. The printing apparatus according to claim 1 or claim 2. S1≦Q1 / (√(2×P1 / ρ1))...(1)

5. When S is the opening area of ​​the plurality of suction holes in the region of the support plate corresponding to the second negative pressure chamber, Q2 is the airflow rate of the second fan, P2 is the static pressure of the second fan, and ρ2 is the density of the gas drawn into the second fan, then the following equation (2) is satisfied. The printing apparatus according to claim 4. S2≦Q2 / (√(2×P2 / ρ2))...(2)

6. The first fan and the second fan have substantially the same suction capacity. The printing apparatus according to claim 5.

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