Dryer

Abstract

To provide a dryer which can properly dry a recording medium without increasing a size and costs.SOLUTION: A dryer 1 includes: a transport member 11 which supports a recording medium and transports the recording medium in a predetermined transport direction; a heating device 5 which heats the recording medium transported by the transport member 11 under a high temperature environment; a dry chamber 7 which is disposed at an upstream side of the heating device 5 in a transport direction of the recording medium and preliminarily dries the recording medium transported by the transport member 11; and paths 57, 59 which allow the heating device 5 and the dry chamber 7 to communicate with each other.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a drying device that dries, while conveying, a recording medium on which an image has been formed by an inkjet method. [Background technology]

[0002] An image forming system including an inkjet image forming apparatus is provided with a drying device that dries an image formed on a recording medium with ink. Drying devices generally include a heater that radiates infrared rays. For example, the drying device described in Patent Document 1 includes a first drying means and a second drying means that radiate infrared rays. The first drying means and the second drying means are arranged in order in the conveying direction of a sheet (recording medium). It is said that the drying efficiency is improved by selectively irradiating the sheet with the first heating means based on information about the sheet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-175528 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a drying device using infrared rays as in Patent Document 1, if the recording medium is suddenly irradiated with infrared rays, the ink may boil and cause a dryness similar to that of a burst bubble. Alternatively, the moisture contained in the recording medium may suddenly vaporize and expand, causing surface cracks in the coated paper. Furthermore, the temperature difference around the through holes in the conveyor belt may cause unevenness in the holes in the belt.

[0005] Therefore, the drying device is generally configured to reduce the heater output and increase the conveying distance of the recording medium so as not to dry the recording medium too quickly, but such a configuration has problems such as an increase in the size of the drying device and an increase in the number of heaters, which increases the cost and power consumption.

[0006] SUMMARY OF THE PRESENT DISCLOSURE In consideration of the above circumstances, an object of the present invention is to provide a drying device that can properly dry a recording medium without increasing the size or cost. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the drying device of the present invention is a drying device that dries a recording medium on which an image is formed while transporting it, and is characterized in that it includes a transport member that supports the recording medium and transports it in a predetermined transport direction, a heating device that heats the recording medium transported by the transport member in a high-temperature environment, a drying chamber that is positioned upstream of the heating device in the transport direction of the recording medium and pre-dries the recording medium transported by the transport member, and a path that connects the heating device and the drying chamber.

[0008] In the present invention, the heating device may include a fan that takes in air from the outside and blows it toward the recording medium transported by the transport member, a heater that is positioned downstream of the fan in the air blowing direction and irradiates infrared rays toward the recording medium transported by the transport member, and a housing on whose top surface the fan is positioned and in which the heater is housed, and the path may include an upper path that connects the space in the housing upstream of the fan in the blowing direction with the drying chamber, and a lower path that connects the space between the heater and the transport member with the drying chamber, and the upper path's opening to the drying chamber and the lower path's opening to the drying chamber may be opposed to each other.

[0009] In the present invention, the path may be provided with a fan that blows air from the heating device toward the drying chamber.

[0010] In the present invention, a temperature sensor may be provided for detecting the temperature inside the drying chamber, and the amount of air sent into the drying chamber may be controlled based on the temperature inside the drying chamber detected by the temperature sensor. Effect of the Invention

[0011] According to the present invention, the ink can be dried without a sudden increase in temperature, so that problems such as dryness, surface cracking of coated paper, and unevenness in belt holes can be reduced. [Brief description of the drawings]

[0012] [Figure 1] 1 is a front view showing the inside of a drying device according to an embodiment of the present invention. [Diagram 2] FIG. 4 is a front view illustrating the flow of air in a drying chamber of the drying device according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, a drying device according to an embodiment of the present invention will be described with reference to the drawings.

[0014] First, the overall configuration of the drying device 1 will be described with reference to Fig. 1. Fig. 1 is a front view showing the inside of the drying device 1. L and R shown in each figure indicate the left and right sides of the drying device 1, respectively.

[0015] The drying device 1 includes a transport device 3 that transports a recording medium on which an image is formed by an inkjet method, a heating device 5 that dries the image (ink) formed on the recording medium transported by the transport device 3 in a high-temperature environment, and a drying chamber 7 that pre-dries the recording medium before drying the ink by the heating device 5.

[0016] First, a description will be given of the conveying device 3. The conveying device 3 includes a conveying belt 11 that conveys the recording medium along a conveying direction X from right to left in Fig. 1, a conveying plate 13 that supports the conveying belt 11, a suction device 15 that attracts the recording medium to the conveying belt 11, and front and rear side plates 17 that support these.

[0017] First, the front and rear side plates 17 will be described. The front and rear side plates 17 are plate-shaped members that are long in the width direction (the direction intersecting the conveying direction X, the left-right direction) and are arranged with a gap in between in the front-rear direction. Two chambers 19 aligned in the conveying direction X are formed in the lower part of the space between the front and rear side plates 17.

[0018] A driving roller 21 and a driven roller 23 are supported between the front and rear side plates 17. The driving roller 21 is rotatably supported at the downstream end (left end) of the front and rear side plates 17 in the conveying direction X. The driven roller 23 is rotatably supported at the upstream end (right end) of the front and rear side plates 17 in the conveying direction. A drive shaft of the driving roller 21 is connected to a motor (not shown).

[0019] Next, the conveyor belt 11 will be described. The conveyor belt 11 is an endless belt, and a large number of through holes penetrating in the thickness direction are formed on the entire surface. The conveyor belt 11 is wound around a driving roller 21 and a driven roller 23. The driving roller 21 is driven by a motor to rotate, and the conveyor belt 11 circulates and runs in a counterclockwise direction in FIG. 1. The outer surface of the conveyor belt 11 along the upper track becomes the conveying surface on which the recording medium is conveyed. Thus, the conveyor belt 11 is an example of a conveying member for conveying a recording medium in the present invention.

[0020] Next, the conveying plate 13 will be described. The conveying plate 13 is supported by front and rear side plates 17 so as to come into contact with the inner peripheral surface (the surface behind the conveying surface) of the conveying belt 11 running on the upper track. When the conveying belt 11 runs, the inner peripheral surface of the conveying belt 11 slides along the upper surface of the conveying plate 13. A large number of through holes penetrating the conveying plate 13 in the thickness direction are formed on the entire surface.

[0021] Next, the suction device 15 will be described. The suction device 15 is disposed in each of two chambers 19 formed between the front and rear side plates 17. When the suction device 15 is driven, air is sucked in through holes in the conveyor belt 11 and the conveyor plate 13. As a result, the recording medium on the conveyor surface of the conveyor belt 11 is attracted to the conveyor belt 11.

[0022] Next, a description will be given of the heating device 5. The heating device 5 includes two heater units 31, two fans 33 provided in each heater unit 31, and a housing 35 in which these are housed.

[0023] The housing 35 is formed in a box shape with an opening at the bottom. The opening at the bottom is covered with a protective net 37. Upper and lower openings 39, 41 are formed at the upper and lower parts, respectively, of the side plate (right side plate) on the upstream side in the conveying direction X of the housing 35.

[0024] The two heater units 31 are arranged side by side in the conveying direction X in the hollow portion of the housing 35. Each heater unit 31 has a plurality of infrared heaters 43 arranged side by side in the conveying direction X, and a reflector 45 that reflects infrared rays emitted from each infrared heater 43. The infrared rays emitted from the infrared heaters 43 are reflected by the reflector 45 and irradiated downward. An upper opening 39 formed in the right side plate of the housing 35 is arranged above the heater units 31. On the other hand, a lower opening 41 formed in the right side plate of the housing 35 is arranged below the heater units 31.

[0025] Two fans 33 are provided on the upper surface (top surface) of each heater unit 31. The fans 33 take in air inside the housing 35 and blow it out downward. The air blown out downward is heated as it passes through the heater unit 31, generating downward hot air.

[0026] The heating device 5 is disposed downstream in the conveying direction X above the conveying surface of the conveyor belt 11 of the conveying device 3, with a predetermined distance therebetween.

[0027] Next, the drying chamber 7 will be described with reference to Fig. 2. Fig. 2 is a front view showing the drying chamber 7. The drying chamber 7 is formed in a box shape with an open bottom and a height and length (length along the conveying direction X) smaller than those of the housing 35 of the heating device 5. The opening on the bottom is covered with a protective net 51. An upstream opening 53 and a downstream opening 55 are formed in the lower parts of the side plates on the upstream side (right side) and downstream side (left side) of the drying chamber 7 in the conveying direction, respectively. The upstream opening 53 and the downstream opening 55 face each other in the conveying direction X.

[0028] The drying chamber 7 is disposed above the conveying surface of the conveyor belt 11 of the conveyor 3 on the upstream side of the heating device 5 in the conveying direction, with a predetermined distance from the conveying surface. In this manner, the drying chamber 7 and the heating device 5 are disposed in sequence along the conveying direction X. The upstream opening 53 of the drying chamber 7 communicates with the upper opening 39 of the housing 35 of the heating device 5 via the upper duct 57. The upper duct 57 extends horizontally from the upper opening 39 to the upstream side above the top plate of the drying chamber 7, and then bends downward along the upstream side plate of the drying chamber 7 to communicate with the upstream opening 53. In addition, the downstream opening 55 of the drying chamber 7 communicates with the lower opening 41 of the housing 35 of the heating device 5 via the lower duct 59. In this manner, the upper duct 57 and the lower duct 59 are an example of the upper path and the lower path that communicate the heating device 5 and the drying chamber 7 in the present invention.

[0029] An upper duct 57 is provided at its inlet with an upper blower fan 61. A lower duct 59 is provided with a lower blower fan 63.

[0030] The drying operation of the drying device 1 having the above configuration will be described. In the conveying device 3, the driving roller 21 is driven to rotate and the conveying belt 11 runs. Thereafter, the recording medium on which an image is formed by the inkjet method is conveyed to the conveying surface of the conveying belt 11. In addition, the suction device 15 is driven. As a result, air is taken in from the through holes of the conveying belt 11 and the through holes of the conveying plate 13 as described above, and a negative pressure is created above the conveying surface of the conveying belt 11. As a result, the recording medium is attracted to the conveying surface. In this way, the recording medium is conveyed along the conveying direction X while being attracted to the conveying surface.

[0031] Furthermore, the heater unit 31 and the fan 33 of the heating device 5 are driven. As described above, the infrared rays emitted from the infrared heater 43 are reflected by the reflector 45 and irradiated downward. Also, the air blown downward by the fan 33 passes through the heater unit 31 and is heated, generating downward hot air. In this way, the heating device 5 blows out heated air (hot air) downward. Also, as the heater unit 31 is driven, the temperature inside the housing 35 of the heating device 5 increases.

[0032] Further, the upper blower fan 61 and the lower blower fan 63 are driven. Then, as shown by the arrow in FIG. 2, the upper blower fan 61 causes air in the upper space in the housing 35 (the space above the heater unit 31) to enter the upper duct 57 from the upper opening 39, and the air passes through the upper duct 57 and flows into the drying chamber 7 from the upstream opening 53. Further, the lower blower fan 63 causes heated air in the space below the heater unit 31 to enter the lower duct 59 from the lower opening 41, and flows into the drying chamber 7 through the downstream opening 55. This causes the temperature in the drying chamber 7 to rise. However, since the temperature of the upper space in the housing 35 is lower than the temperature of the space below the heater unit 31, the temperature in the drying chamber 7 is lower than the temperature of the hot air blown out from the heating device 5.

[0033] In addition, since the upstream opening 53 and the downstream opening 55 are disposed opposite to each other, the air flowing in from the upstream opening 53 (the outlet of the upper duct 57 to the drying chamber 7) and the downstream opening 55 (the outlet of the lower duct 59 to the drying chamber 7) collides in the center of the drying chamber 7, reducing the wind speed of the two air flows. This makes it easier for the flowing air to remain in the drying chamber 7. In addition, the heated air that has flowed in to the drying chamber 7 leaks out downward from the drying chamber 7.

[0034] Then, the recording medium conveyed to the conveying surface of the conveyor belt 11 first comes into contact with this leaked heated air, and the ink on the recording medium is preliminarily dried. The temperature of the heated air is not high enough to boil the ink, and the air speed is slower than the hot air blown out from the heating device 5, so that the ink is dried secondarily. The recording medium is then conveyed from below the drying chamber 7 to below the heating device 5. This allows the preliminarily dried ink to be completely dried.

[0035] As is clear from the above description, the drying device 1 of the present invention can dry ink without a sudden increase in temperature, thereby reducing the above problems (dryness, surface cracking of coated paper, and unevenness in belt holes). Furthermore, since there is no need to increase the length of the conveying surface of the conveyor belt 11, the drying device 1 can be prevented from becoming large. Furthermore, the number of heater units 31 can be reduced, thereby reducing costs and power consumption.

[0036] Furthermore, since the temperature of the air in the drying chamber 7 can be increased to an appropriate temperature by utilizing the air whose temperature has been increased by the heating device 5, there is no need to provide a separate mechanism for increasing the temperature of the air in the drying chamber 7.

[0037] Furthermore, as described above, the air leaking out of the drying chamber 7 has a lower temperature and a slower wind speed than the hot air blown out of the heating device 5, so that the ink can be dried without a sudden increase in temperature. Also, the air that has flowed into the drying chamber 7 does not easily escape from the drying chamber 7, so that preliminary drying can be performed efficiently.

[0038] A temperature sensor 65 (see FIG. 1) may be disposed inside the drying chamber 7, and the driving of the upper and lower ventilation fans 61, 63 may be controlled based on the temperature measured by the temperature sensor 65. For example, when the temperature inside the drying chamber 7 is lower than a predetermined temperature, the rotation speed of the lower ventilation fan 63 is increased so as to take in more of the hotter air below the heater unit 31 into the drying chamber 7.

[0039] Although the present invention has been described with respect to a specific embodiment, the present invention is not limited to the above embodiment. The above embodiment may be variously changed, substituted, or modified without departing from the scope and spirit of the present invention, and the claims include all embodiments that may be included within the scope of the technical idea. [Explanation of symbols]

[0040] 1 Drying device 5 Heating device 7 Drying room 11 Conveyor belt (conveyor member) 35 Housing 33 Fans 43 Infrared Heater 57 Upper duct (upper route) 59 Lower duct (lower route) 61, 63 Fan 65 Temperature Sensor

Claims

1. A drying device that dries a recording medium on which an image is formed while conveying the recording medium, A conveying member that supports the recording medium and conveys it in a predetermined conveying direction; a heating device that heats the recording medium conveyed by the conveying member in a high-temperature environment; a drying chamber arranged upstream of the heating device in a conveying direction of the recording medium, the drying chamber pre-drying the recording medium conveyed by the conveying member; a passage communicating between the heating device and the drying chamber.

2. The heating device includes: a fan that takes in air from the outside and blows it toward the recording medium being transported by the transport member; a heater that is disposed downstream of the fan in a direction in which air is blown and that irradiates infrared rays toward the recording medium being transported by the transport member; a housing having a top surface on which the fan is disposed and in which the heater is housed; The route is an upper passage communicating a space in the housing upstream of the fan in the blowing direction with the drying chamber; a lower path communicating a space between the heater and the conveying member with the drying chamber; Including, 2. The drying device according to claim 1, wherein an outlet of the upper path to the drying chamber and an outlet of the lower path to the drying chamber are opposed to each other.

3. 2. The drying device according to claim 1, wherein the path is provided with a fan for blowing air from the heating device toward the drying chamber.

4. A temperature sensor is provided to detect the temperature inside the drying chamber, 2. The drying device according to claim 1, wherein the amount of air sent into the drying chamber is controlled based on the temperature inside the drying chamber detected by the temperature sensor.

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