Cooling structure for circuit board and printer

Abstract

To provide a cooling structure for a circuit board and a printer that improve a cooling effect.SOLUTION: A cooling structure 100 for a circuit board 103 comprises: a circuit board 103 in which circuit components 104 are mounted on a mounting surface 103U; a board box 101 which accommodates the circuit board 103; an intake fan 115 which is supported on a top surface 101a for taking in outside air FA and sending it toward the circuit components 104; and an exhaust fan 117 which is supported on a side surface 101c for exhausting hot air HA. The intake fan 115, the circuit board 103, and the exhaust fan 117 are arranged so as to be able to exhaust the hot air HA from the mounting surface 103U side and a back surface 103L side.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a cooling structure for a circuit board and a printing apparatus.

Background Art

[0002] Conventionally, in an electronic device such as a printing apparatus, a cooling structure for cooling a circuit board inside a housing has been known. For example, Patent Document 1 discloses a cooling structure for cooling a heat-generating circuit component mounted on a circuit board via a heat conductor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the cooling structure described in Patent Document 1 has a problem that it is difficult to improve the cooling effect. Specifically, the heat of the circuit component is conducted to the metal plate facing the circuit board via a heat conductor. Also, the air blown by the cooling fan hardly reaches the back surface of the circuit board. Therefore, with respect to the heat propagated from the circuit component to the back surface of the circuit board, there is a possibility that the cooling effect cannot be sufficiently obtained. That is, a cooling structure for a circuit board that improves the cooling effect has been demanded.

Means for Solving the Problems

[0005] The cooling structure of the circuit board includes a circuit board on which circuit components are mounted on the mounting surface, a board box in which the circuit board is housed, an intake fan supported on the opposing surface of the board box facing the mounting surface, taking in outside air of the board box and blowing it toward the circuit components, and an exhaust fan supported on the intersecting surface of the board box having a direction different from the mounting surface, discharging hot air to the outside of the board box, and the intake fan, the circuit board, and the exhaust fan are arranged so as to be able to discharge the hot air from the side of the mounting surface and the side of the back surface of the circuit board with respect to the mounting surface.

[0006] The printing apparatus includes a printing unit that performs printing on a medium, a circuit board on which circuit components for driving the printing unit are mounted on the mounting surface, a board box in which the circuit board is housed, an intake fan supported on the opposing surface of the board box facing the mounting surface, taking in outside air of the board box and blowing it toward the circuit components, and an exhaust fan supported on the intersecting surface of the board box having a direction different from the mounting surface, discharging hot air to the outside of the board box, and the intake fan, the circuit board, and the exhaust fan are arranged so as to be able to discharge the hot air from the side of the mounting surface and the side of the back surface of the circuit board with respect to the mounting surface.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0008] In the embodiments described below, a cooling structure 100 of a circuit board and a printing apparatus 1 including the cooling structure 100 will be exemplified and described with reference to the drawings. The printing apparatus 1 is a large-format printer that performs printing on a continuous sheet of form. Note that the printing apparatus of the present invention is not limited to the following configuration.

[0009] In the following figures, the XYZ axes are attached as coordinate axes orthogonal to each other, the direction indicated by each arrow is defined as the + direction, and the direction opposite to the + direction is defined as the - direction. When the printing apparatus 1 is installed on a horizontal plane, the -Z direction becomes the vertical direction. In the following description, the +Z direction is defined as upward and the -Z direction is defined as downward. Note that in the following figures, for the sake of illustration, the sizes of the respective members are made different from the actual ones.

[0010] As shown in FIG. 1, the printing apparatus 1 according to the present embodiment includes a cooling structure 100, a structural member 10, a feeding unit 20, media support units 30, 50, 70, a conveying unit 40, a printing unit 60, a blowing unit 80, a winding unit 90, and a housing (not shown). In FIG. 1, for the sake of illustration, the housing that houses the printing unit 60 and the like is omitted. In the description of FIG. 1 given below, unless otherwise specified, the state as viewed from the -X direction will be described.

[0011] The printing apparatus 1 manufactures a printed matter by attaching ink to a medium M. In the printing apparatus 1, the medium M is fed from a roll body R1 that is a web and becomes a printed matter, and the printed matter is wound up to become a roll body R2.

[0012] The movement path of the medium M from when it is fed from the roll body R1 until it is wound up as the roll body R2 is defined as a conveyance path. In FIG. 1, the conveyance path is indicated by a dashed line. In the conveyance path, the side of the web of the medium M is also referred to as the upstream, and the side where the medium M and the printed matter advance is also referred to as the downstream. In the conveyance path, in the order from upstream to downstream, the feeding unit 20, the media support unit 30, the conveying unit 40, the media support unit 50 and the printing unit 60, the media support unit 70 and the blowing unit 80, and the winding unit 90 are arranged in the above order. Note that in the conveyance path, the direction in which the medium M moves from upstream to downstream is also referred to as the conveyance direction.

[0013] [[ID=1⑨]] The structural member 10 is a frame that supports the above components of the printing apparatus 1. The structural member 10 is formed by assembling a plurality of sheet metal members, tubular members, and the like. In the structural member 10, casters, installation members, and the like may be arranged at the portion that contacts the lower floor.

[0014] The feeding unit 20 includes a roll body holding unit 21. The feeding unit 20 is arranged in the -Y direction below the printing apparatus 1. The roll body holding unit 21 rotatably supports the roll body R1 about an axis along the X-axis. The medium M is pulled by the conveying unit 40 and fed downstream from the roll body R1 for supply. The roll body R1 is detachable from the printing apparatus 1. The medium M is conveyed by the conveying unit 40 substantially upward from the roll body holding unit 21 and proceeds to the medium support unit 30. Note that the feeding unit 20 may include a driving unit capable of feeding and winding the medium M.

[0015] The medium M is appropriately selected according to the type of ink to be attached to the medium M, the use of the printed matter, and the like. In the printing apparatus 1, since so-called soft solvent ink is used as the ink, a sheet made of polyvinyl chloride or the like is applied as the medium M.

[0016] The medium support unit 30 has a substantially arc-shaped curved surface and supports the conveyed medium M. The conveying direction of the medium M is changed from the substantially +Z direction to the substantially +Y direction by the above curved surface. The medium M is conveyed while sliding in contact with the above curved surface of the medium support unit 30. The medium M proceeds from the medium support unit 30 to the conveying unit 40.

[0017] Although not shown, the medium support unit 30 incorporates an electric heater that heats the medium M. The electric heater pre-heats the medium M before the ink is attached. Thereby, the fixability and solubility of the ink with respect to the medium M are improved.

[0018] The conveying unit 40 includes conveying rollers 41 and 42. The conveying rollers 41 and 42 are paired and their sides are in contact with each other. The conveying roller 41 is disposed below the conveying path, and the conveying roller 42 is disposed above the conveying path. The conveying rollers 41 and 42 each rotate about an axis along the X-axis.

[0019] The conveying roller 41 is driven to rotate by a drive motor (not shown). The conveying roller 42 is a driven roller and rotates in a direction opposite to that of the conveying roller 41 due to the rotation of the conveying roller 41. When the conveying roller 41 rotates counterclockwise, the conveying roller 42 rotates clockwise. Thereby, the medium M is sandwiched between the conveying rollers 41 and 42 and conveyed downstream. Then the medium M proceeds to the medium support portion 50.

[0020] The medium support portion 50 is a member constituting a so-called platen. The upper surface of the medium support portion 50 supports the medium M along the XY plane. In the medium support portion 50, the conveying direction of the medium M is the +Y direction. The surface facing upward of the medium M becomes the printing surface.

[0021] Although not shown, the medium support portion 50 incorporates a heating heater for heating the medium M. The heating heater heats the medium M when ink adheres thereto. Thereby, the fixing property and solubility of the ink with respect to the medium M are improved, and volatile components such as solvents contained in the ink are more likely to volatilize.

[0022] The printing unit 60 performs printing on the medium M. The printing unit 60 includes a head 61 and a carriage 62. The printing unit 60 is disposed above the medium support portion 50. The carriage 62 is supported above the structural member 10 so as to be capable of reciprocating movement along the X-axis. The above reciprocating movement is driven by a carriage motor (not shown). The carriage 62 supports the head 61 above the medium support portion 50.

[0023] The head 61 attaches ink to the printing surface of the medium M supported on the upper surface of the medium support portion 50. The head 61, together with the carriage 62, reciprocates along the X-axis within a range including the region vertically opposed to the medium support portion 50.

[0024] Although not shown, a nozzle surface is disposed on the surface of the head 61 facing downward. A plurality of nozzle rows are provided on the nozzle surface. Each nozzle row consists of a plurality of nozzles. For each nozzle row, inks of various colors such as black, cyan, yellow, and magenta are individually supplied from an ink storage container (not shown). The inks of various colors are ejected from each nozzle row toward the printing surface of the medium M.

[0025] The ink applied to the printing apparatus 1 is the soft solvent ink as described above. The soft solvent ink is, for example, a solvent ink that does not contain intentionally added water and contains a glycol ether-based solvent or a lactone-based solvent as a main solvent. Note that the ink ejected from the head 61 also includes a treatment liquid and a clear ink that does not contain a coloring material.

[0026] In the medium support portion 50, while the medium M is being conveyed in the +Y direction, the head 61 together with the carriage 62 is reciprocated along the X-axis. At this time, by attaching ink to the printing surface of the medium M at an arbitrary timing, an image such as a picture, a photograph, text, or a pattern is printed on the medium M. The printed medium M is pulled by the winding portion 90 and conveyed, and proceeds to the medium support portion 70.

[0027] The medium support portion 70 has a curved surface and supports the conveyed medium M. The medium M is conveyed while sliding in contact with the curved surface of the medium support portion 70. The conveyance direction of the medium M is changed from the +Y direction to the substantially -Z direction by the curved surface. Although not shown, the medium support portion 70 incorporates a heating heater that heats the medium M. The heating heater promotes the volatilization of the volatile components contained in the ink attached to the medium M.

[0028] The air blowing unit 80 blows air onto the printing surface of the medium M to assist in the volatilization of the above-mentioned volatile components. The air blowing unit 80 is supported by the structural member 10 above the conveyance path of the medium support unit 70. The air blowing unit 80 blows air over the entire range along the X-axis of the medium M.

[0029] By heating by the medium support unit 70 and blowing air by the air blowing unit 80, the drying of the ink adhered to the medium M is promoted. Therefore, the medium M can be wound up by the winding unit 90 downstream. The medium M advances from the medium support unit 70 to the winding unit 90.

[0030] The winding unit 90 includes a roll body holding unit 91. The winding unit 90 is arranged in the +Y direction below the printing apparatus 1. The roll body holding unit 91 winds up the medium M as a roll body R2 by the rotational drive of a drive motor (not shown). The roll body R2 rotates about an axis along the X-axis. Thus, the medium M, which is a printed matter, becomes the roll body R2. The roll body R2 can be removed from the printing apparatus 1.

[0031] The cooling structure 100 includes a circuit board 103, which is the control unit of the printing apparatus 1, and a board box 101 that houses the circuit board 103. The cooling structure 100 is arranged above the printing apparatus 1 in the -Y direction. Details of the cooling structure 100 will be described later.

[0032] As shown in FIG. 2, the cooling structure 100 includes a board box 101, an intake duct 105, a circuit board 103, an intake fan 115, a heat sink 116, an exhaust fan 117, an exhaust duct 107, a temperature sensor 121, and a humidity sensor 122. Note that the intake duct 105 is an example of the duct of the present invention.

[0033] The substrate box 101 is a box-shaped member in the form of a substantially rectangular parallelepiped, and houses an intake fan 115, a circuit board 103, and a heat sink 116 inside. By arranging the circuit board 103 inside the substrate box 101, the adhesion of dust, ink mist generated from the head 61, etc. to the circuit board 103 can be suppressed. Also, the circuit board 103 is isolated from the heat dissipated from the medium support portions 30, 50, 70. The substrate box 101 is arranged inside a housing (not shown) of the printing apparatus 1.

[0034] In the substrate box 101, the length along the X-axis is longer than the lengths along the Y-axis and the Z-axis. The substrate box 101 has six inner surfaces, namely, a top surface 101a, a bottom surface 101b, side surfaces 101c, 101d, and two side surfaces (not shown).

[0035] The top surface 101a is an inner surface facing downward, extends along the XY plane, and constitutes the upper surface inside the substrate box 101. The bottom surface 101b is an inner surface facing upward, extends along the XY plane and faces the top surface 101a, and constitutes the lower surface inside the substrate box 101. The side surface 101c is an inner surface facing the +X direction, extends along the YZ plane, and is arranged in the -X direction inside the substrate box 101. The side surface 101d is an inner surface facing the -X direction, extends along the YZ plane and faces the side surface 101c, and is arranged in the +X direction inside the substrate box 101. The two side surfaces (not shown) are inside the substrate box 101, both extend along the XZ plane and face each other.

[0036] The circuit board 103 is substantially plate-shaped. The main surface of the circuit board 103 extends along the XY plane, is spaced apart from the top surface 101a, and is also spaced apart from the bottom surface 101b. When viewed from the -Y direction, the distance between the bottom surface 101b and the circuit board 103 is, for example, approximately half of the distance between the top surface 101a and the circuit board 103. In the circuit board 103, the main surface facing upward is defined as the mounting surface 103U, and the main surface facing downward is defined as the back surface 103L. The circuit board 103 is, for example, a glass epoxy substrate.

[0037] The top surface 101a of the substrate box 101 is an example of the opposing surface of the substrate box 101 of the present invention and faces the mounting surface 103U in the vertical direction. The side surface 101c of the substrate box 101 is an example of the intersecting surface of the substrate box 101 of the present invention, and the extending direction of the surface is different from that of the mounting surface 103U. The side surface 101c of the substrate box 101 intersects the surface obtained by extending the mounting surface 103U. The side surface 101c of the substrate box 101 supports the exhaust fan 117. The side surface 101d is an example of the back wall surface of the substrate box 101 of the present invention and faces the side surface 101c, which is an intersecting surface supporting the exhaust fan 117, in the direction along the X-axis. When viewed from the -Y direction, the side surface 101c is separated from the -X direction end of the circuit board 103, and the side surface 101d is separated from the +X direction end of the circuit board 103.

[0038] A plurality of circuit components 104 are mounted on the mounting surface 103U of the circuit board 103. The circuit board 103 and the plurality of circuit components 104 drive the printing unit 60. The plurality of circuit components 104 may include circuit components that are electrically connected to each component of the printing apparatus 1 described above and integrally control the operation of the printing apparatus 1.

[0039] The plurality of circuit components 104 are arranged to protrude upward from the mounting surface 103U. The plurality of circuit components 104 include hardware that constitutes a circuit for driving the head 61. Further, the plurality of circuit components 104 may include hardware such as a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The circuit board 103 controls the printing apparatus 1 by executing a predetermined control program by the CPU. The ROM is a non-volatile storage device and stores the control program executed by the CPU and the data processed by the control program. The RAM constitutes the work area of the CPU. The CPU expands the control program read from the ROM or the like into the RAM and executes the expanded control program to control the printing apparatus 1.

[0040] Among the plurality of circuit components 104 and the wirings of the circuit board 103, there are those that generate heat when driving the head 61. The circuit components 104 that generate heat may have their performance degraded due to a temperature rise. Also, in some cases, the influence of the heat generation may spread to other circuit components 104. In contrast, in the printing apparatus 1, the cooling structure 100 improves the cooling effect of the circuit board 103 and the plurality of circuit components 104.

[0041] The heat sink 116 is attached to the back surface 103L of the circuit board 103. The heat sink 116 promotes the cooling of the circuit board 103 by heat dissipation. The heat sink 116 is arranged closer to the side surface 101c than the side surface 101d when viewed from the -Y direction. The heat sink 116 is substantially rectangular parallelepiped. The surface facing upward of the heat sink 116 is in contact with the back surface 103L of the circuit board 103. The region below the heat sink 116 is spaced apart from the bottom surface 101b.

[0042] Although not shown in the figure, the heat sink 116 has a plurality of grooves extending along the X-axis. The plurality of grooves are continuous from the end in the +X direction to the end in the -X direction in the heat sink 116. When viewed from the +X direction, the plurality of grooves are arranged in a comb-like shape. The plurality of grooves increase the surface area of the heat sink 116 and improve the heat dissipation performance. Since the plurality of grooves extend along the X-axis, air easily flows along the X-axis.

[0043] The heat sink 116 is formed of a metal having a relatively high thermal conductivity such as aluminum, aluminum alloy, or copper.

[0044] The intake duct 105 is arranged on the surface facing upward of the substrate box 101, which is on the back side of the top surface 101a. The substrate box 101 communicates with the outside of a housing (not shown) of the printing apparatus 1. The outside air of the substrate box 101 is introduced into the inside of the substrate box 101 through the intake duct 105.

[0045] The air inside the housing of the printing apparatus 1 may contain ink mist generated from the printing unit 60 and dust generated from the medium M or the like. Further, the air inside the housing may be at a higher temperature than the outside air due to the influence of the electric heater such as the medium support unit 50 described above. Therefore, it is preferable that the outside air of the substrate box 101 is the outside air of the housing of the printing apparatus 1.

[0046] According to this, it is possible to suppress the occurrence of problems caused by the adhesion of ink mist and dust to the circuit board 103 and the plurality of circuit components 104. Further, the circuit board 103 and the plurality of circuit components 104 can be efficiently cooled using outside air that is relatively lower in temperature than the air inside the housing of the printing apparatus 1.

[0047] The intake duct 105 is a box-shaped member that is substantially trapezoidal when viewed from above and has a thickness in the vertical direction. When viewed from above, in the intake duct 105, the length of the end side in the -Y direction is longer than the length of the end side in the +Y direction.

[0048] The intake duct 105 has openings 105g and 105h. The opening 105g is open to the outside of the intake duct 105. The opening 105h communicates the inside of the intake duct 105 and the inside of the substrate box 101. The outside air can be efficiently introduced by the intake duct 105.

[0049] The opening 105g is disposed at a portion corresponding to the end side in the -Y direction. The opening 105g is a substantially rectangular opening when viewed from the -Y direction and is open to the outside world. The longitudinal direction of the opening 105g is along the X axis. The opening 105g communicates with an air intake port of the housing described later. The outside air of the housing is introduced through the air intake port and the opening 105g. The introduced outside air advances in the substantially +Y direction and reaches the opening 105h.

[0050] The opening 105h is a substantially circular opening when viewed through from above and is disposed near the end side in the +Y direction of the intake duct 105. An intake fan 115 is disposed below the opening 105h. The outside air is sucked by the intake fan 115 and advances downward from the opening 105h.

[0051] The intake fan 115 takes in the outside air of the substrate box 101, that is, the outside air of the housing of the printing apparatus 1, and blows it toward the plurality of circuit components 104. The intake fan 115 is supported inside the substrate box 101, that is, on the top surface 101a, and is disposed directly below the opening 105h. When viewed from the -Y direction, the intake fan 115 is disposed slightly closer to the -X direction with respect to the center line in the direction along the X-axis of the substrate box 101. In other words, in the direction along the X-axis, the intake fan 115 is located closer to the side surface 101c than the side surface 101d.

[0052] The intake fan 115 takes in the outside air through the intake duct 105. The outside air blown into the substrate box 101 from the intake fan 115 cools the circuit board 103 and the plurality of circuit components 104 and becomes hot air, and then proceeds to the exhaust fan 117. Known electric fans or the like can be applied to the intake fan 115 and the exhaust fan 117 described later.

[0053] The exhaust fan 117 discharges the hot air from the inside to the outside of the substrate box 101. The exhaust fan 117 is supported by the side surface 101c of the substrate box 101. When viewed from the +X direction, the rotation center of the exhaust fan 117 is located at a position substantially overlapping with the circuit board 103. Therefore, the exhaust fan 117 can discharge the hot air from both the side of the mounting surface 103U of the circuit board 103 and the side of the back surface 103L.

[0054] The exhaust duct 107 guides the hot air discharged from the substrate box 101 by the exhaust fan 117 to the outside of the housing. The exhaust duct 107 is attached to the back side of the side surface 101c which is the outside of the substrate box 101. The exhaust duct 107 is a substantially box-shaped member. The inside of the exhaust duct 107 communicates with the inside of the substrate box 101 through the exhaust fan 117 supported by the side surface 101c. An opening (not shown) is disposed on the surface of the exhaust duct 107 facing downward. The inside of the exhaust duct 107 communicates with the outside of the housing of the printing apparatus 1 through the opening of the exhaust duct 107.

[0055] The hot air inside the substrate box 101 advances into the exhaust duct 107 by the exhaust fan 117 and is discharged substantially below the exhaust duct 107. On the other hand, the outside air for cooling the circuit board 103 and the like is introduced by the intake duct 105 from above the substrate box 101 and in the -Y direction. As a result, it becomes difficult for the discharged hot air to be mixed into the outside air introduced from the intake duct 105, and the cooling effect of the circuit board 103 is improved.

[0056] As described above, the intake fan 115, the circuit board 103, and the exhaust fan 117 are arranged to cool the side of the mounting surface 103U and the side of the back surface 103L of the circuit board 103 with respect to the mounting surface 103U and to be able to discharge hot air.

[0057] In the vertical direction, the distance between the intake fan 115 and the mounting surface 103U of the circuit board 103 is shorter than the length Lf of the intake fan 115 in the air supply direction, which is the -Z direction. Since the intake fan 115 is arranged relatively close to the circuit board 103, the air supply of the intake fan 115 easily cools the plurality of circuit components 104 and the circuit board 103. Also, in the space between the top surface 101a and the circuit board 103, the generation of convection is suppressed, and the flow of the air current along the mounting surface 103U easily occurs. Thereby, the cooling effect of the circuit board 103 can be further improved.

[0058] In the direction along the X axis, the interval L1 between the side surface 101d and the +X direction end of the circuit board 103 is wider than the interval L2 between the side surface 101c and the -X direction end of the circuit board 103. The air supply of the intake fan 115 easily flows between the side surface 101d and the circuit board 103 due to the flow of the gas inside the substrate box 101. Therefore, the outside air introduced by the intake fan 115 wraps around to the side of the back surface 103L of the circuit board 103, and the cooling from the back surface 103L of the circuit board 103 and the heat sink 116 is further promoted. Thereby, the cooling effect of the circuit board 103 can be further improved.

[0059] In addition, in the circuit board 103, the arrangement of the mounting surface 103U and the back surface 103L is not limited to the above. The mounting surface 103U may face downward and the back surface 103L may face upward. In this case, the distance between the bottom surface 101b and the circuit board 103, the distance between the top surface 101a and the circuit board 103, the distance between the intake fan 115 and the mounting surface 103U of the circuit board 103, the interval L1 between the side surface 101d and the +X direction end of the circuit board 103, and the interval L2 between the side surface 101c and the -X direction end of the circuit board 103 may be appropriately changed.

[0060] The temperature sensor 121 and the humidity sensor 122 are inside the intake duct 105 and are arranged near the opening 105g. The temperature sensor 121 and the humidity sensor 122 are electrically connected to the circuit board 103.

[0061] The temperature sensor 121 detects the temperature around the printing device 1 and is utilized to grasp the usage environment of the printing device 1. The detected temperature may be transmitted to the circuit board 103 and utilized for driving control of the head 61 in order to cope with fluctuations in the ink ejection amount due to temperature changes. The humidity sensor 122 detects the humidity around the printing device 1 and is utilized to grasp the usage environment of the printing device 1. The detected humidity may be transmitted to the circuit board 103 and utilized for driving control of the head 61 in order to cope with fluctuations in the ink ejection amount due to humidity changes.

[0062] Since the temperature sensor 121 and the humidity sensor 122 are installed in the depressions provided on the inner surface of the intake duct 105, it is difficult to obstruct the flow of outside air introduced into the intake duct 105. In addition, since outside air of the housing is introduced into the intake duct 105, it becomes difficult to be affected by the hot air that has cooled the circuit board 103 and the like, and the outside air temperature and the outside air humidity can be accurately detected. As the temperature sensor 121, known sensors such as a thermistor and a thermocouple can be applied. As the humidity sensor 122, known sensors such as an electrostatic capacitance type or an electric resistance type electric humidity sensor can be applied. Also, a sensor in which the temperature sensor and the humidity sensor are integrated may be used.

[0063] As shown in FIG. 3, two openings 134 are provided on the side surface facing the -Y direction of the outer surface of the substrate box 101. Each opening 134 is rectangular. The two openings 134 are arranged adjacent to each other on a straight line along the X-axis with their longitudinal directions along the X-axis.

[0064] Wiring (not shown) is passed through the two openings 134 of the substrate box 101. The wiring electrically connects the circuit board 103 and the printing unit 60 described above. In this embodiment, an FFC (Flexible Flat Cable) is applied as the wiring.

[0065] A shielding member 130 is provided outside the two openings 134, that is, in the -Y direction. The shielding member 130 is substantially rectangular and has an area sufficient to cover the two openings 134. The shielding member 130 is formed of, for example, a resin film or sheet.

[0066] Slits 131 are formed in the shielding member 130 at positions overlapping the respective openings 134 when viewed from the -Y direction. The FFC, which is the wiring, is passed through each slit 131. The shielding member 130 covers the portions other than the wiring in the opening 134, that is, the regions other than the regions through which the wiring passes.

[0067] The shielding member 130 restricts the inflow and outflow of outside air into and out of the inside of the substrate box 101 through the openings 134. Thereby, while ensuring the electrical connection to the printing unit 60, the airtightness inside the substrate box 101 is improved. Therefore, the cooling effect on the circuit board 103 and the plurality of circuit components 104 is likely to be manifested.

[0068] As shown in FIG. 4, in the cooling structure 100, outside air FA is introduced into the substrate box 101 from the opening 105g of the intake duct 105, and hot air HA is discharged from the opening 107h of the exhaust duct 107 to the outside of the substrate box 101. In FIG. 4, the airflows including the outside air FA and the hot air HA are indicated by white arrows.

[0069] The outside air FA is sucked by the intake fan 115 and enters the substrate box 101 from the opening 105h. The outside air FA is blown onto the mounting surface 103U of the circuit board 103 and is roughly divided into an air flow heading in the substantially -X direction and an air flow heading in the substantially +X direction.

[0070] The air flow heading in the substantially -X direction absorbs heat from the mounting surface 103U and circuit components 104 (not shown) and then proceeds in the -X direction as part of the hot air HA and reaches the exhaust fan 117.

[0071] The air flow heading in the substantially +X direction proceeds in the +X direction while absorbing heat from the mounting surface 103U and the circuit components 104. Then, when this air flow hits the side surface 101d, its direction changes, and it becomes an air flow that proceeds in the -X direction between the back surface 103L and the bottom surface 101b. This air flow absorbs heat from the back surface 103L and the heat sink 116 and then proceeds in the -X direction as part of the hot air HA and reaches the exhaust fan 117.

[0072] The exhaust fan 117 discharges the air flow from the side of the mounting surface 103U and the air flow from the side of the back surface 103L as hot air HA substantially downward from the opening 107h of the exhaust duct 107.

[0073] As shown in FIG. 5, the cooling structure 100 is housed in the housing 9 of the printing apparatus 1. The housing 9 has an air intake 9i and a partition portion 9a.

[0074] The air intake 9i is arranged corresponding to the opening 105g of the intake duct 105. The outside air FA of the housing 9 is introduced into the opening 105g through the air intake 9i.

[0075] As described above, the hot air HA is discharged substantially downward from the opening 107h by the exhaust fan 117. The partition portion 9a is substantially plate-shaped and is arranged to protrude downward from the region that houses the cooling structure 100 of the housing 9.

[0076] The partition portion 9a makes it more difficult for the hot air HA to mix further into the outside air FA. Therefore, the cooling effect of the circuit board 103 and the plurality of circuit components 104 by the outside air FA is further improved.

[0077] According to this embodiment, the following effects can be obtained.

[0078] The cooling effect of the circuit board 103 can be improved. Specifically, the exhaust fan 117 discharges the hot air HA from the side of the mounting surface 103U and the back surface 103L of the circuit board 103. Therefore, heat dissipation is promoted also from the back surface 103L through which the heat of the plurality of circuit components 104 propagates. Accordingly, it is possible to provide the cooling structure 100 of the circuit board 103 for improving the cooling effect and the printing apparatus 1.

[0079] Since it is a relatively space-saving and highly efficient cooling structure 100, it is possible to mainly suppress the vertical dimension of the printing apparatus 1. Since the circuit board 103 is housed in the substantially sealed substrate box 101, it is possible to suppress the adhesion of ink mist and dust to the circuit board 103.

Explanation of Signs

[0080] 1... printing apparatus, 9... housing, 60... printing unit, 100... cooling structure, 101... substrate box, 101a... top surface as the opposing surface, 101c... side surface as the intersecting surface, 101d... side surface as the back wall surface, 103... circuit board, 103L... back surface, 103U... mounting surface, 104... circuit component, 105... intake duct as a duct, 115... intake fan, 116... heat sink, 117... exhaust fan, 121... temperature sensor, 122... humidity sensor, 130... shielding member, 134... opening, FA... outside air, HA... hot air, L1, L2... intervals, Lf... length in the blowing direction of the intake fan.

Claims

1. A circuit board on which circuit components are mounted on a mounting surface, a board box that houses the circuit board, an intake fan that is supported on a facing surface of the board box facing the mounting surface, takes in outside air of the board box, and blows the air toward the circuit components, an exhaust fan that is supported on an intersecting surface of the board box that is in a different direction from the mounting surface, and discharges hot air to the outside of the board box, and a cooling structure for a circuit board, wherein the intake fan, the circuit board, and the exhaust fan are arranged so as to be able to discharge the hot air from a side of the mounting surface and a side of a back surface of the circuit board with respect to the mounting surface.

2. The intake fan is supported inside the board box, and a distance between the intake fan and the circuit components is shorter than a length of the intake fan in a blowing direction, the cooling structure for a circuit board according to claim 1.

3. A heat sink is attached to the back surface of the circuit board, the cooling structure for a circuit board according to claim 1.

4. A distance between a back wall surface of the board box facing the intersecting surface that supports the exhaust fan and the circuit board is wider than a distance between the intersecting surface that supports the exhaust fan and the circuit board, the cooling structure for a circuit board according to claim 1.

5. A printing unit that performs printing on a medium, a circuit board on which circuit components that drive the printing unit are mounted on a mounting surface, a board box that houses the circuit board, an intake fan that is supported on a facing surface of the board box facing the mounting surface, takes in outside air of the board box, and blows the air toward the circuit components, an exhaust fan that is supported on an intersecting surface of the board box that is in a different direction from the mounting surface, and discharges hot air to the outside of the board box, and a printing apparatus, wherein the intake fan, the circuit board, and the exhaust fan are arranged so as to be able to discharge the hot air from a side of the mounting surface and a side of a back surface of the circuit board with respect to the mounting surface.

6. A housing that houses the printing unit, a duct that communicates with the outside of the housing, and the board box is arranged inside the housing, and the intake fan takes in the outside air through the duct, the printing apparatus according to claim 5.

7. The printing apparatus according to claim 6, further comprising a temperature sensor inside the duct.

8. The printing apparatus according to claim 6, further comprising a humidity sensor inside the duct.

9. It has wiring that electrically connects the circuit board and the printing unit through the opening of the substrate box, The printing apparatus according to claim 6, wherein a shielding member is provided in the opening to cover a portion other than the wiring and restrict the inflow of outside air.

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