Drying device

Abstract

To stably transport a sheet while circulating air in a machine.SOLUTION: A drying device comprises: a warm air blowing unit 8 which blows warm air toward a sheet S transported by a drying belt 7; a suction unit 59 which sucks air from an inner circumference side of the drying belt 7 via a plurality of suction ports 11; and an exhaust duct 52 having a second exhaust port 53 which is connected to a first exhaust port 50a of the suction unit 59, and exhausts air exhausted from the first exhaust port 50a into a housing. The second exhaust port 53 is arranged in such a manner that exhaust air is exhausted upward at a position on an upper side of a sheet transport path for the sheet S guided by the drying belt 7 with respect to a vertical direction, and the exhaust port 53 is located on a back side B of the housing opposite to a front side F of the housing with respect to a drying belt unit 5 regarding a sheet width direction W.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a drying device that dries a sheet on which an image is formed with ink. [Background technology]

[0002] In an image forming system that forms an image with ink, there are processes for drying a sheet and blowing air onto the sheet. For example, Patent Document 1 proposes a drying device that transports a sheet by a belt and dries the sheet by blowing hot air onto the sheet (see Patent Document 1). In this drying device, a suction transport section having a suction belt with multiple holes suctions and transports the sheet, while a hot air blowing unit blows air from above onto one side of the sheet to dry it.

[0003] Generally, hot air blowing units use a heater to heat the air and then blow the hot air onto the sheet, which tends to consume a lot of power. Therefore, it is desirable to circulate the hot air after blowing onto the sheet from the viewpoint of reusing heat, rather than simply discharging it outside the machine and discarding it, for more efficient drying. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-206304 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the drying device described in Patent Document 1 does not take into consideration circulating the hot air sucked in by the suction conveying section into the interior of the machine. Therefore, depending on the position of the exhaust port returning the hot air from the suction conveying section to the interior of the machine, the circulating airflow or the airflow caused by the circulation may act on the suction conveying section, making it difficult for the sheet to adhere to the suction conveying section, and there is a risk of the conveying becoming unstable.

[0006] An object of the present invention is to provide a drying device capable of stably transporting sheets while circulating air inside the device. [Means for solving the problem]

[0007] The drying device of the present invention is a drying device that dries a sheet on which an image has been formed by ejecting ink, by blowing hot air onto the sheet, and includes a housing, a hollow rotor housed in the housing and having a plurality of through holes penetrating an inner circumferential side and an outer circumferential side, and a sheet transport section that transports the sheet by rotation of the rotor, an air blower unit that is provided vertically above the sheet transport section and has an air intake port that draws in air and an air outlet port that blows the air drawn in from the air intake port toward the sheet transported by the rotor, and a blower fan that blows air from the air intake port toward the air outlet inside the air blower duct, and the drying device includes a blower unit that draws in air from the inner circumferential side of the rotor through the plurality of through holes, The apparatus comprises a suction unit having a first exhaust duct having a first exhaust port for exhausting sucked air, and a suction fan inside the first exhaust duct that blows air from the multiple holes toward the first exhaust port, and a second exhaust duct connected to the first exhaust port of the suction unit and having a second exhaust port for exhausting the air exhausted from the first exhaust port into the inside of the housing, wherein the second exhaust port is positioned so as to exhaust air upward at an upper position relative to a sheet transport path of a sheet guided by the rotating body in the vertical direction, and is positioned on the rear side of the housing opposite the front side of the housing relative to the sheet transport section in the sheet width direction that intersects the sheet transport direction.

[0008] The drying device of the present invention is a drying device that dries a sheet on which an image has been formed by ejecting ink, by blowing hot air onto the sheet, and includes a housing, a sheet transport section that has a hollow rotor that is housed in the housing and has a plurality of through holes penetrating from an inner peripheral side to an outer peripheral side, and transports the sheet by rotation of the rotor, an air supply duct that is provided vertically above the sheet transport section and has an air intake port that draws in air and an air outlet port that blows the air drawn in from the air intake port toward the sheet transported by the rotor, and a blower fan that blows air from the air intake port toward the air outlet inside the air supply duct. , an exhaust duct having an exhaust port that draws in air from the inner side of the rotating body through the multiple holes and exhausts the drawn-in air, and a suction fan that blows air from the multiple holes inside the exhaust duct toward the exhaust port; and a connecting duct that connects the exhaust port and the blower duct and guides the air exhausted from the exhaust port to the blower duct, the connecting duct being positioned on the rear side of the housing, opposite the front side of the housing, relative to the sheet conveying section, in a sheet width direction that intersects the sheet conveying direction. Effect of the Invention

[0009] According to the present invention, it is possible to stably transport a sheet while circulating air inside the machine. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional view showing the configuration of an image forming system according to a first embodiment. [Diagram 2] 1 is a schematic cross-sectional view showing a drying module, a print module, and a fixing module according to a first embodiment. [Diagram 3] FIG. 2 is a perspective view showing a state in which an upper door is open in the drying module according to the first embodiment. [Figure 4] FIG. 2 is a perspective view showing a drying section of the hot air blowing unit according to the first embodiment. [Diagram 5]3 is a cross-sectional view showing a drying section of the hot air blowing unit according to the first embodiment as viewed from the side. FIG. [Figure 6] 1 is a cross-sectional view showing a drying belt according to a first embodiment as viewed from the front. [Figure 7] FIG. 2 is a perspective view showing a suction box according to the first embodiment. [Figure 8] FIG. 11 is a cross-sectional view showing a drying section of a hot air blowing unit according to a second embodiment, as viewed from the side. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] <First embodiment> A first embodiment of the present invention will be described in detail below with reference to Figures 1 to 7. First, a schematic configuration of an image forming system according to this embodiment will be described with reference to Figure 1.

[0012] [Image formation system] The inkjet recording system 100 of this embodiment uses an inkjet recording method in which ink is ejected to form an image on a sheet, and is a so-called sheet-fed inkjet recording device that forms an ink image on a sheet using two liquids, namely, a reaction liquid and ink. The sheet may be any recording material that can receive ink, such as paper such as plain paper or thick paper, plastic film such as an overhead projector sheet, specially shaped sheets such as envelopes or index paper, and cloth.

[0013] 1, the inkjet recording system 100 of this embodiment includes a feeding module 1000, a printing module 2000, and a drying module 3000. The inkjet recording system 100 further includes a fixing module 4000, a cooling module 5000, an inverting module 6000, and a stacking module 7000. The sheet S supplied from the feeding module 1000 is subjected to various processes while being transported along a transport path in each module, and is finally discharged to the stacking module 7000.

[0014] Each of the modules from the feeding module 1000 to the stacking module 7000 may have a separate housing, and these housings may be connected to configure the inkjet recording system 100. Alternatively, the feeding module 1000, the print module 2000, the drying module 3000, the fixing module 4000, the cooling module 5000, the reversing module 6000, and the stacking module 7000 may be arranged in a single housing.

[0015] The feeding module 1000 has storage chambers 1500a, 1500b, and 1500c for storing sheets S, and the storage chambers 1500a to 1500c are provided so as to be able to be pulled out to the front side F of the apparatus in order to store the sheets S. The sheets S are fed one by one in each of the storage chambers 1500a to 1500c by a separation belt and a transport roller, and are transported to the print module 2000. The number of storage chambers 1500a to 1500c is not limited to three, and one, two, or four or more may be provided.

[0016] The print module 2000 as an image forming section has a pre-imaging registration correction section (not shown), a print belt unit 2010, and a recording section 2020. The sheet S conveyed from the feeding module 1000 has its inclination and position corrected by the pre-imaging registration correction section and is conveyed to the print belt unit 2010. The recording section 2020 is disposed at a position facing the print belt unit 2010 with respect to the conveying path. The recording section 2020 is an inkjet recording section that forms an image by discharging ink onto the conveyed sheet S from above with a recording head. A plurality of recording heads that discharge ink are arranged along the conveying direction. In this embodiment, in addition to the four colors of Y (yellow), M (magenta), C (cyan), and Bk (black), a total of five line-type recording heads corresponding to the reaction liquid are provided. The sheet S is attracted and conveyed by the print belt unit 2010, so that a clearance between the sheet S and the recording head is ensured.

[0017] The number of ink colors and recording heads are not limited to the above five. The inkjet method may be a method using a heating element, a method using a piezoelectric element, a method using an electrostatic element, a method using a MEMS (Micro Electro Mechanical Systems) element, or the like. Each color of ink is supplied to the recording head from an ink tank (not shown) via an ink tube. The ink contains a resin component of "0.1% by mass to 20.0% by mass" based on the total mass of the ink, water, a water-soluble organic solvent, a coloring material, wax, additives, and the like.

[0018] When the sheet S on which an image is formed by the recording unit 2020 is transported by the print belt unit 2010, it is detected by an in-line scanner (not shown) arranged downstream of the recording unit 2020 in the transport direction of the sheet S. Here, the misalignment and color density of the image formed on the sheet S are detected, and the image formed on the sheet S, its density, etc. are corrected based on the misalignment and color density of the image.

[0019] The drying module 3000 is an example of a drying device, and dries the sheet S on which an image is formed by ejecting ink by blowing hot air onto the sheet S. As shown in FIG. 2, the drying module 3000 has a decoupling section 40, a drying belt unit 5, and a hot air blowing unit 8. The drying module 3000 reduces the liquid content of the ink and reaction liquid applied to the sheet S in order to improve the fixation of the ink to the sheet S by the subsequent fixing module 4000. The sheet S on which the image is formed is transported to the decoupling section 40 arranged in the drying module 3000. In the decoupling section 40, a frictional force is generated between the sheet S and the belt by the wind pressure of the wind blown from above, and the sheet S is transported by the belt. In this way, the sheet S placed on the belt is transported by the frictional force, thereby preventing the sheet S from shifting when the sheet S is transported between the print belt unit 2010 and the decoupling section 40. The sheet S transported from the decoupling section 40 is adsorbed and transported by the drying belt unit 5, and the ink and reaction liquid applied to the sheet S are dried by blowing hot air onto the sheet S from the hot air blowing unit 8 arranged above the belt.

[0020] In this way, the ink and reaction liquid applied to the sheet S are heated by the drying module 3000 to promote evaporation of the moisture, thereby preventing so-called cockling, in which ink splatters on the sheet S and leaves a border-like line around the periphery. As a heater for heating the air, for example, an electric heating wire or an infrared heater is preferable from the standpoint of safety and energy efficiency. In addition, the drying method may be configured by combining a method of applying hot air, a method of irradiating the surface of the sheet S with electromagnetic waves (ultraviolet rays, infrared rays, etc.), and a conductive heat transfer method by contact with a heating element.

[0021] 1, a fixing module 4000 as a fixing system has a fixing belt unit 4100 as a fixing device. The fixing belt unit 4100 fixes ink onto the sheet S by passing the sheet S conveyed from the drying module 3000 between a heated upper belt unit and a lower belt unit.

[0022] The cooling module 5000 has a plurality of cooling sections 5001, which cool the high-temperature sheet S transported from the fixing module 4000. The cooling section 5001, for example, takes in outside air into a cooling box with a fan to increase the pressure inside the cooling box, and cools the sheet S by blowing air from the cooling box through a nozzle due to the pressure against the sheet S. The cooling sections 5001 are disposed on both sides of the transport path of the sheet S, and cool both sides of the sheet S.

[0023] The cooling module 5000 is provided with a transport path switching unit 5002. The transport path switching unit 5002 switches the transport path of the sheet S depending on whether the sheet S is transported to the reversing module 6000 or to a double-sided transport path for double-sided printing in which images are formed on both sides of the sheet S.

[0024] The inversion module 6000 has an inversion section 6400. The inversion section 6400 inverts the sheet S being conveyed, and changes the orientation of the sheet S when it is discharged to the stacking module 7000. The stacking module 7000 has a top tray 7200 and a stacking section 7500, and stacks the sheet S conveyed from the inversion module 6000.

[0025] During double-sided printing, the sheet S is transported to a transport path below the cooling module 5000 by the transport path switching unit 5002. Thereafter, the sheet S passes through a double-sided transport path including the fixing module 4000, the drying module 3000, the print module 2000, and the feeding module 1000, and is returned to the print module 2000. The double-sided transport section of the fixing module 4000 is provided with an inversion unit 4200 that inverts the sheet S. The sheet S returned to the print module 2000 has an image formed with ink on the other side on which the image is not formed, and is then discharged from the drying module 3000 through the inversion module 6000 to the stacking module 7000.

[0026] [Drying module] Next, the drying module 3000 will be described in detail with reference to FIGS. 2 to 7. FIG. 2 is a schematic diagram showing a state in which the print module 2000, the drying module 3000, and the fixing module 4000 are connected. FIG. 3 is a perspective view showing the drying module 3000. In each drawing, the front side of the inkjet recording system 100 is represented as the front side F, the rear side as the rear side B, the right side as the right direction R, the left side as the left direction L, the upper side as the upper direction U, and the lower side as the lower direction D. In addition, in this embodiment, the front side F of the inkjet recording system 100 is the front side, that is, the side where the operation panel and the like are arranged and where the user is positioned during use, and the rear side B is the rear side, that is, the opposite side to the front side F with respect to the sheet width direction W. Here, the sheet width direction W is the front-rear direction in this embodiment. Similarly, the front side F and the rear side B are defined for the drying module 3000 as in the inkjet recording system 100.

[0027] As shown in Fig. 2, the drying module 3000 has a decoupling unit 40, a drying belt unit 5, and a hot air blowing unit 8. These are collectively referred to as the drying function unit 300, and are housed in a housing 301 (see Fig. 3). The drying function unit 300 is disposed at the upper part of the drying module 3000, and has a linear sheet transport path 1 for receiving the sheet S discharged from the print module 2000, drying the sheet S, and then delivering the sheet S to the fixing module 4000. With regard to the sheet transport direction in this sheet transport path 1, the upstream and downstream parts of the drying function unit 300 have different functions.

[0028] As shown in Fig. 3, the housing 301 has a first storage section 302 that stores the hot air blowing unit 8, a second storage section 303 that stores the drying belt unit 5, and a rotation shaft 304 that rotatably connects the first storage section 302 and the second storage section 303 to each other. The rotation shaft 304 connects an upper part on one side (back side B) of the second storage section 303 to a lower part on one side (back side B) of the first storage section 302 with respect to the sheet width direction, with the sheet conveying direction being the longitudinal direction. The rotation shaft 304 allows the first storage section 302 to be opened and closed relative to the second storage section 303 by rotating about the rotation shaft 304. This allows the first storage section 302 to be opened and closed from the front side F of the device, improving maintainability.

[0029] A decoupling section 40 serving as an air blowing device is disposed upstream of the drying function section 300. The decoupling section 40 has a decoupling belt unit 2 serving as a sheet conveying section and a cold air blowing unit 3 serving as an air blowing section. The cold air blowing unit 3 is disposed vertically above the decoupling belt unit 2, which conveys the sheet S in a substantially horizontal direction. A plurality of cold air blowing units 3 are disposed adjacent to each other along the sheet conveying direction. The decoupling belt unit 2 has a rotating endless belt 2a. The cold air blowing unit 3 blows cold air (air) from above the decoupling belt unit 2, thereby pressing the sheet S against the belt 2a and conveying it. The decoupling belt unit 2 has a plurality of holes for allowing the air blown from the cold air blowing unit 3 to pass from the blowing surface to the belt opposing side. In the following, air that is not heated by a heater or the like is also referred to as "cold air".

[0030] When the leading edge of the sheet S reaches the decoupling belt unit 2 of the drying module 3000, the trailing edge of the sheet S is still on the print belt unit 2010 of the print module 2000. The print belt unit 2010 has an endless print belt 4 (see FIG. 1) that sucks and transports the sheet. An image is formed on the sheet S on the print belt 4, and the sheet S is sucked and transported on the print belt 4. In order not to disturb this image forming process, the force pressing the sheet S against the belt 2a is weaker than the suction force of the print belt 4, and the belt 2a is driven at a speed slightly faster than that of the print belt 4. In other words, while the trailing edge of the sheet S is on the print belt 4, the sheet S is always allowed to slide against the belt 2a.

[0031] On the other hand, the moment the trailing end of the sheet S leaves the area of ​​the print belt 4, the transportation of the sheet S becomes dependent on the belt 2a. At this time, it is necessary to control the air blowing force of the cold air blowing unit 3 so that the sheet S does not slip due to the resistance to transportation. Therefore, the speed of the air blown from the cold air blowing unit 3 to the sheet S transported on the belt 2a is controlled to a predetermined pressure using a pressure sensor (not shown) provided inside the cold air blowing unit 3 and an intake fan (not shown) provided in the intake section. The cold air blowing unit 3 has a blowing surface provided with a large number of blowing holes for passing air so that a uniform pressing force can be applied to the sheet S. [Drying section] Next, the drying section 6 will be described with reference to Fig. 2. The drying section 6 is disposed downstream of the drying function section 300. The drying section 6 has a drying belt unit 5 and a hot air blowing unit 8. The hot air blowing units 8 are disposed vertically above the drying belt unit 5, and a plurality of the hot air blowing units 8 are disposed adjacent to each other along the sheet conveying direction.

[0032] In the drying section 6, the sheet S is sucked by the drying belt unit 5 to be adsorbed onto the drying belt 7, while the sheet S is dried by the hot air blowing unit 8 blowing hot air from above in the vertical direction, and conveyed while suppressing waviness called cockling. In order to quickly dry the sheet S, the surface temperature of the drying belt 7 is adjusted to a predetermined temperature by controlling heater rollers 63 and 65 (described later) based on the temperature detected by a temperature sensor 67 (described later) provided inside the drying belt unit 5. This heats the sheet S being conveyed by the drying belt 7.

[0033] [Hot air blowing unit] Next, the hot air blowing unit 8 will be described with reference to Figs. 4 and 5. Fig. 4 is a perspective view of the main parts of the hot air blowing unit 8 and the drying belt unit 5, which are the drying function parts, as seen from the rear direction. In the figure, the left direction L is the sheet conveying direction D1. Fig. 5 is a schematic cross-sectional view of the main parts when cut along the line AA in Fig. 4. The arrows in Fig. 5 indicate the flow of air. The hot air blowing unit 8 has a blower fan 13, a blower duct 14, a heater 15, a temperature sensor 16, and the like. In this embodiment, the blower fan 13 is an axial fan. However, it is not limited to an axial fan, and other blower sources such as a sirocco fan may be used. The heater 15 is a sheathed heater. However, it is not limited to a sheathed heater, and other heat sources such as a Kanthal heater may be used.

[0034] Air supply duct 14 has heater 15 and temperature sensor 16 therein, and the exhaust side of blower fan 13 is connected to an end of air supply duct 14. That is, blower fan 13 is provided at the upstream end of air supply duct 14. Heater 15 is disposed on the downstream side of the air supply path of blower fan 13. Heater 15 is an example of a heating section, and is provided downstream of blower fan 13 in air supply duct 14, and heats the air blown through air supply duct 14.

[0035] The surface facing the sheet S further downstream of the heater 15 is the blowing surface 12, and a plurality of blowing holes 10 are formed therein. In this embodiment, the air supply duct 14 is formed in a generally horizontal U-shape as a whole when viewed from the sheet conveying direction, with the upper part being the intake side to which the blowing fan 33 is connected, and the lower part being the exhaust side to which the blowing nozzle 30 is formed. The temperature sensor 16 is attached to the upper surface at the upper part of the air supply duct 14. In addition, a pressure sensor 18 for detecting the pressure inside the air supply duct 14 is provided adjacent to the temperature sensor 16.

[0036] As a result, the air outside or inside the machine sent from the blower fan 13 is heated by the heater 15 and blown through the blowing holes 10 of the blower duct 14 to the drying belt 7 of the drying belt unit 5 or the sheet S on the drying belt 7. The blowing holes 10 are provided in an area that includes the maximum sheet width so that air can be blown to the entire width of the sheet S having the maximum sheet width. The temperature and pressure in the blower duct 14 are measured by the temperature sensor 16 and the pressure sensor 18, and the heat generation amount of the heater 15 and the rotation speed of the blower fan 13 are controlled by a control unit (not shown) based on the measured values. As a result, the hot air blowing unit 8 blows hot air to press the sheet S onto the drying belt 7, and dries the ink on the sheet S. The distance from the suction end position of the print belt 4 to the suction start position of the drying belt 7 is set to be longer than the maximum sheet length.

[0037] That is, the hot air blowing unit 8 is an example of an air blowing unit, and is provided vertically above the drying belt unit 5, and has an air blowing duct 14 and an air blowing fan 13. The air blowing duct 14 has an air intake port 14a that draws in air, and air blowing holes 10 that are air outlets that blow out the air drawn in from the air intake port 14a toward the sheet S being transported by the drying belt 7. The air blowing fan 13 blows air from the air intake port 14a toward the air blowing holes 10 inside the air blowing duct 14.

[0038] [Drying belt unit] Next, the dryer belt unit 5 will be described with reference to Figs. 6 and 7. Fig. 6 is a cross-sectional view of the dryer belt unit 5, and Fig. 7 is a perspective view of the suction box 50. In both figures, the left direction L is the sheet conveying direction D1. The dryer belt unit 5 has a dryer belt 7, which is a rotating endless conveying belt, a plurality of rollers around which the dryer belt 7 is stretched, and a heater 66 for heating the dryer belt 7, and conveys the sheet S while heating it with the dryer belt 7. The dryer belt 7 is an example of a hollow rotating body and a conveying belt, and has suction holes 11, which are a plurality of through holes penetrating the inner circumference side and the outer circumference side. The dryer belt unit 5 is an example of a sheet conveying section, is housed in a housing 301, has the dryer belt 7, and conveys the sheet S by the rotation of the dryer belt 7.

[0039] In this embodiment, the drying belt unit 5 has five rollers that stretch the drying belt 7, namely, a driving roller 61, a tension roller 62, a heater roller 63, a counter roller 64, and a heater roller 65. The driving roller 61 is driven by a motor (not shown), and the driving roller 61 rotates to transport the drying belt 7. The tension roller 62 is a roller that urges the drying belt 7 outward with a spring (not shown) to prevent the drying belt 7 from bending. Each of the heater rollers 63 and 65 has a heater 66 therein and transfers heat to the drying belt 7. Each heater 66 is, for example, a halogen heater. A temperature sensor 67 is provided upstream of the heater roller 65 and measures the temperature of the drying belt 7. The heater roller 63 has a larger diameter than the heater roller 65, and the heater roller 63 mainly heats the drying belt 7, and the heater roller 65 finely adjusts the temperature of the drying belt 7.

[0040] The counter roller 64 is a roller that contacts the drying belt 7 from the outside, and increases the contact length between the heater rollers 63 and 65 and the drying belt 7, thereby efficiently transmitting heat to the drying belt 7. The counter roller 64 also has a steering function that prevents the drying belt 7 from shifting by swinging the shaft end up and down using a motor (not shown).

[0041] Between the heater roller 65 and the drive roller 61, a suction box 50 is provided. The upper surface of the suction box 50 is open, and a plurality of belt rollers 54 are arranged therein. The belt rollers 54 are made of PTFE and have, for example, a diameter of about 10 mm and a length in the width direction of about 10 mm. The plurality of belt rollers 54 are arranged on one shaft 54a at intervals of about 10 mm so as to be rotatable independently. Furthermore, the shafts 54a on which the plurality of belt rollers 54 are provided are arranged with the sheet width direction W as the longitudinal direction, and are arranged in the sheet conveying direction. At this time, when viewed from above, the belt rollers 54 of the adjacent shafts 54a are arranged in a staggered manner. Air can flow in the vertical direction in the gap between the staggered belt rollers 54 and the shafts 54a exposed between the belt rollers 54.

[0042] In this embodiment, the drying belt 7 is supported on the suction box 50 by the belt rollers 54. That is, the belt rollers 54 are an example of a support surface portion, and support the area of ​​the drying belt 7 that transports the sheet S. Since the belt rollers 54 themselves are rotatable, belt wear due to friction between the drying belt 7 and the belt rollers 54 can be suppressed, which contributes to improving the lifespan of the drying belt 7. Note that, although the upper surface of the suction box 50 is configured by arranging a plurality of belt rollers 54 in this embodiment, the present invention is not limited to this, and may be configured, for example, by a top plate having a plurality of holes.

[0043] 4, a suction fan 51 is provided on the back side B of the suction box 50. When the suction fan 51 is driven, the air inside the suction box 50 is exhausted and the air above is sucked in through the gaps in the belt rollers 54. Suction holes 11 are also formed in the drying belt 7, and the sheet S on the drying belt 7 is sucked in through the gaps in the belt rollers 54 and the suction holes 11, and fixed on the drying belt 7.

[0044] The suction holes 11 of the drying belt 7 each have a diameter of 0.4 mm, and the intervals between the holes are 3.0 mm to 4.0 mm in the sheet conveying direction D1 and 2.5 mm to 3.0 mm in the sheet width direction W. The suction holes 11 of the drying belt 7 are arranged in a generally staggered pattern when viewed from above, and the holes have an area equivalent to approximately 1.4% of the surface area of ​​the drying belt 7. A pressure sensor 57 is provided below the suction box 50, measuring the pressure inside the suction box 50 via a tube 58. The suction pressure at the suction holes 11 is 1500 Pa to 2000 Pa, and the rotation speed of the suction fan 51 is controlled by a control unit (not shown) based on the output value of the pressure sensor 57.

[0045] In this embodiment, the suction box 50 and the suction fan 51 correspond to the suction unit 59. That is, the suction unit 59 is provided in the drying belt unit 5, and has the suction box 50 and the suction fan 51. The suction box 50 is an example of a first exhaust duct, and has a first exhaust port 50a that sucks air from the inner circumferential side of the drying belt 7 through a plurality of holes (gaps between the belt rollers 54) and exhausts the sucked air. The suction fan 51 blows air from the plurality of holes of the suction box 50 toward the first exhaust port 50a.

[0046] Thus, in this embodiment, the multiple belt rollers 54 have multiple holes and suck air from the drying belt 7 side (conveyor belt side) through the multiple holes, thereby adsorbing the drying belt 7 to the multiple belt rollers 54. Also, the multiple belt rollers 54 suck air through the suction holes 11 of the drying belt 7, thereby adsorbing the sheet S to the drying belt 7.

[0047] [Cyclic configuration] Next, the configuration for circulating exhaust gas in the suction box 50 of the present invention will be described in detail with reference to Figures 6 and 7. The suction box 50 is provided on the inner circumferential side of the drying belt 7. The suction box 50 has belt rollers 54 supporting the drying belt 7 on its upper surface, and a suction fan 51 is connected to its rear surface (see Figure 4). The suction box 50 itself is disposed and supported between drying belt frames 55 fixed to the housing. The suction fan 51 is connected to the suction box 50 from the outer rear surface of the drying belt frame 55 in the sheet width direction W through a hole in the drying belt frame 55.

[0048] An exhaust duct 52 is connected to the rear of the suction fan 51. The exhaust duct 52 is formed with an exhaust port 53 facing vertically upward. The exhaust port 53 is disposed above the drying belt 7. That is, the exhaust duct 52 is an example of a second exhaust duct, and has a second exhaust port 53 that is connected to the first exhaust port 50a of the suction unit 59 and exhausts the air exhausted from the first exhaust port 50a into the inside of the housing 301. In this embodiment, the second exhaust port 53 is disposed so as to exhaust air upward at a position above the sheet conveying path of the sheet S guided by the drying belt 7 in the vertical direction. In addition, the second exhaust port 53 is disposed on the rear side B of the housing 301 (see FIG. 3) opposite to the front side F of the housing 301, relative to the drying belt unit 5, in the sheet width direction W intersecting the sheet conveying direction. Furthermore, the air intake 14a of the hot air blowing unit 8 is positioned inside the housing 301, closer to the rear side B of the housing 301 than the drying belt unit 5 in the sheet width direction W, and above the second exhaust port 53 in the vertical direction.

[0049] The suction fan 51 is provided so as to exhaust the air inside the suction box 50 to the outside of the suction box 50, toward the exhaust duct 52. The suction box 50 is sealed except for the gaps between the belt rollers 54 on the upper surface and the opening to the suction fan 51. When the suction fan 51 is driven, air is sucked in through the gaps between the belt rollers 54 and the suction holes 11 in the drying belt 7 above it. The amount of air blown from the hot air blowing unit 8 is greater than the amount of air sucked in by the suction box 50. That is, the amount of air blown by the suction fan 51 is smaller than the amount of air blown by the blower fan 13. However, this is not limited to this, and the amount of air blown by the suction fan 51 may be approximately the same as the amount of air blown by the blower fan 13, or the amount of air blown by the suction fan 51 may be greater than the amount of air blown by the blower fan 13 depending on other conditions.

[0050] At this time, if a sheet S is placed on the drying belt 7, the sheet S is sucked and fixed on the drying belt 7 and transported in accordance with the rotation of the drying belt 7. At both ends of the drying belt 7 in the sheet width direction W on which the sheet S is not placed, the hot air blown from the blowing holes 10 is sucked directly into the suction box 50 and returned to the inside of the machine from the exhaust port 53 via the suction fan 51. Thereafter, it is sucked in by the blower fan 13 of the hot air blowing unit 8 and blown out again from the blowing holes 10 as hot air to be blown onto the sheet. By circulating the hot air instead of exhausting it outside the machine in this way, thermal energy can be effectively utilized and energy consumption can be reduced compared to heating the outside air.

[0051] As described above, according to the drying module 3000 of the present embodiment, the second exhaust port 53 is disposed so as to exhaust air upward at a position above the sheet conveying path of the sheet S guided by the drying belt 7 in the vertical direction. The second exhaust port 53 is disposed on the rear side B of the housing 301 (see FIG. 3) opposite to the front side F of the housing 301, farther from the drying belt unit 5, in the sheet width direction W intersecting the sheet conveying direction. That is, the second exhaust port 53 is disposed at a position that does not overlap with the sheet passing area when viewed from above. Therefore, the exhaust air from the drying belt unit 5 is not directly blown onto the sheet S of the drying belt 7, and is less susceptible to the influence of turbulent air currents, such as rising air currents caused by hot air exhaust. Therefore, even if hot air is circulated inside the housing 301, stable conveyance of the sheet S can be realized without lifting the sheet S on the drying belt 7. Therefore, the sheet S can be stably conveyed while circulating air inside the machine.

[0052] Also, by arranging the second exhaust port 53 on the rear side B of the device, the exhaust air is less likely to hit the user. Furthermore, by arranging the second exhaust port 53 on the rear side B, it is not necessary to arrange the exhaust duct 52 on the front side F of the device. This improves maintainability.

[0053] Furthermore, according to the drying module 3000 of the present embodiment, the intake port 14a of the hot air blowing unit 8 is disposed inside the housing 301, closer to the rear side B of the housing 301 than the drying belt unit 5, and above the second exhaust port 53 in the vertical direction. Therefore, the air discharged from the second exhaust port 53 is easily sucked in through the intake port 14a, and therefore, the air can be effectively prevented from flowing toward the sheet S.

[0054] Furthermore, according to the drying module 3000 of this embodiment, the air volume of the suction fan 51 is set to be smaller than the air volume of the blower fan 13. Therefore, the air volume exhausted from the second exhaust port 53 is smaller than the air volume sucked in at the intake port 14a, so that the exhaust air from the second exhaust port 53 can be effectively prevented from flowing toward the sheet S.

[0055] In the above embodiment, the drying belt 7 is used as the rotating body, but the present invention is not limited to this, and a rotating drum may be used instead. In this case, a number of holes are provided on the surface of the rotating drum, and the sheet S is attracted to the peripheral surface by suction from the inner periphery.

[0056] In the above-described embodiment, the configuration of the image forming system for sheet-fed printing has been described as shown in Fig. 1. However, the image forming system is not limited to sheet-fed presses, and may also be applied to continuous feed presses.

[0057] <Second embodiment> Next, a second embodiment of the present invention will be described in detail with reference to Fig. 8. This embodiment differs from the first embodiment in that it has a connection duct 152 that connects the first exhaust port 50a and the air supply duct 14. However, other configurations are the same as those of the first embodiment, so the same reference numerals are used and detailed description is omitted.

[0058] In this embodiment, as shown in Fig. 8, a connection duct 152 is provided to connect the first exhaust port 50a, which is an exhaust port, and the intake port 14a. The connection duct 152 is a duct that guides the air exhausted from the first exhaust port 50a to the air supply duct 14. The connection duct 152 is disposed on the rear side B of the housing 301, opposite to the front side F of the housing 301, with respect to the sheet width direction W, from the drying belt unit 5. In this embodiment, the connection duct 152 has an opening 70 that communicates with the inside of the housing 301 and sucks in the air inside the housing 301. The opening 70 is not necessarily required.

[0059] As described above, according to this embodiment, the exhaust air from the suction box 50 does not diffuse inside the housing 301, making it possible to efficiently circulate the warm air, thereby further reducing the impact on the sheet S on the drying belt 7.

[0060] In this embodiment, the connection duct 152 connects the first exhaust port 50a and the intake port 14a, but this is not limited to this and it is sufficient if the connection duct 152 connects the first exhaust port 50a and any other location in the air blower duct 14.

[0061] In addition, in this embodiment, the opening 70 opens to the inside of the housing 301, but this is not limited thereto. For example, the opening 70 may be provided in the connection duct 152 near the hot air blowing unit 8 to take in outside air. [Explanation of symbols]

[0062] 5...drying belt unit (sheet conveying section), 7...drying belt (rotating body, conveying belt), 8...hot air blowing unit (air blowing unit), 10...blow hole (air outlet), 11...suction hole (through hole), 13...air blowing fan, 14...air blowing duct, 14a...air intake port, 50...suction box (first exhaust duct), 50a...first exhaust port (exhaust port), 51...suction fan, 52...exhaust duct (second exhaust duct), 53...second exhaust port, 54...roller (support surface section), 59...suction unit, 70...opening, 152...connection duct, 301...housing, 302...first storage section, 303...second storage section, 304...rotating shaft, 3000...drying module (drying device), B...rear side, F...front side, S...sheet

Claims

1. A conveying unit that suctions and conveys a sheet, A blowing unit is provided above the aforementioned transport unit and blows warm air onto the ink discharged onto the sheet being transported. Exhaust duct and A drying apparatus equipped with, The aforementioned transport unit is An endless belt with multiple holes on its surface for transporting sheets, A suction box is placed inside the belt and sucks air from outside the belt through the plurality of holes, A suction fan is provided inside the suction box to draw air into the suction box, A first exhaust port for exhausting the air inside the suction box, It has, The aforementioned spraying unit is A ventilation duct equipped with an air intake port for drawing in air, A fan for blowing air from the aforementioned air duct, A heater for heating the air inside the aforementioned air supply duct, A nozzle is provided opposite the belt and blows air heated in the air duct toward the seat, It has, The exhaust duct has a second exhaust port connected to the first exhaust port, which exhausts the air inside the suction box and the air inside the exhaust duct. The second exhaust port is positioned above the conveying surface of the belt, and is configured to allow air exhausted from the second exhaust port to be drawn in from the intake port. A drying apparatus characterized by the following features.

2. The intake port, the first exhaust port, and the second exhaust port are each provided on the rear side of the device, The drying apparatus according to feature 1.

3. The intake port is positioned above the second exhaust port with respect to the vertical direction. The drying apparatus according to feature 2.

4. The airflow of the suction fan is less than the airflow of the blower fan. The drying apparatus according to feature 1.

5. The suction box has a support surface portion that supports the area of ​​the belt that conveys the sheet, the support surface portion has a plurality of holes, and the belt is adsorbed to the support surface portion through the plurality of holes. The drying apparatus according to feature 1.

6. A first storage section for housing the spraying unit, A second storage section for housing the aforementioned transport unit, A pivot shaft is provided on the rear side of the device along the sheet transport direction, and rotatably connects the first storage section and the second storage section to each other. It also has, The drying apparatus according to feature 1.

7. When viewed in the vertical direction, the second exhaust port does not overlap with the belt. The drying apparatus according to feature 1.

8. The second exhaust port is arranged to exhaust upward, The drying apparatus according to feature 1.

9. The second exhaust port is open upward, The drying apparatus according to feature 1.

10. The exhaust duct is arranged in the vertical direction to span from below to above the conveying surface of the belt. The drying apparatus according to feature 1.

11. The second exhaust port is included in a cross-section along a vertical direction perpendicular to the sheet conveying direction, passing through the intake port. The drying apparatus according to feature 1.

12. A conveying unit that suctions and conveys a sheet, A blowing unit is provided above the aforementioned transport unit and blows warm air onto the ink discharged onto the sheet being transported. Connecting duct and A drying apparatus equipped with, The aforementioned transport unit is An endless belt with multiple holes on its surface for transporting sheets, A suction box is placed inside the belt and sucks air from outside the belt through the plurality of holes, A suction fan is provided inside the suction box to draw air into the suction box, A first exhaust port for exhausting the air inside the suction box, It has, The aforementioned spraying unit is A ventilation duct equipped with an air intake port for drawing in air, A fan for blowing air from the aforementioned air duct, A heater for heating the air inside the aforementioned air supply duct, A nozzle is provided opposite the belt and blows air heated in the air duct toward the seat, It has, The connecting duct connects the first exhaust port and the intake port, and guides the air inside the suction box to the blowing duct. A drying apparatus characterized by the following features.

13. The connecting duct is provided between the first exhaust port and the intake port and has an opening for taking in air from inside the device. The drying apparatus according to feature 12.

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