Sheet drying apparatus and image forming system including the same

Abstract

To provide a sheet drying apparatus which enables a unit for cooling a suction fan and a unit for separating a sheet from a conveyance member to be arranged in a space-saving manner, and to provide an image forming system including the sheet drying apparatus.SOLUTION: A sheet drying apparatus includes a first conveyance portion, a drying portion, a suction fan, an exhaust portion, a first duct, a second duct, a separation fan, a separation duct, a cooling fan, and a cooling duct. The separation fan separates a sheet from the first conveyance portion at a separation position. The separation duct allows the separation fan to communicate with the separation position. The cooling fan cools the suction fan. The cooling duct allows the cooling fan to communicate with the suction fan. The suction fan and the second duct are arranged downstream of the drying portion. The separation fan, the separation duct, the cooling fan, and the cooling duct are arranged downstream of the suction fan and the second duct. The separation duct and the cooling duct are arranged so that at least parts of them overlap with each other when viewed from a width direction horizontally orthogonal to a conveyance direction.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a sheet drying device for drying a sheet on which an image is printed by an inkjet recording device or the like, and an image forming system including the same.

Background Art

[0002] Conventionally, as a recording device such as a facsimile machine, a copying machine, or a printer, an inkjet recording device that ejects ink onto a sheet to form an image has been widely used. Further, a sheet drying device that heats and dries a sheet (paper) to which ink has been attached by an inkjet recording device is known.

[0003] For example, in Patent Document 1, a casing through which a recording medium passes, a first air blowing unit provided above a conveyance path in the vertical direction inside the casing and blowing air downward toward the recording medium conveyed in the conveyance path, a first heating unit that heats the air sent to the recording medium by the first air blowing unit, and an outside air supply unit that supplies outside air to an air rising region inside the casing where the air heated by the first heating unit rises are provided. A recording medium drying device is disclosed.

[0004] In Patent Document 2, a casing in which a suction port and a discharge port are formed, a heater disposed inside the casing, a fan that blows air so that air is inhaled into the casing from the suction port and the air inside the casing is discharged from the discharge port, and a dehumidifying member having a dehumidifying passage that allows the air discharged from the discharge port and blown onto the recording medium to pass through while dehumidifying the air are provided. A drying device for an inkjet printer is disclosed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In a sheet drying device that evaporates and dries aqueous ink using a heater, a suction fan is provided to suck air inside the device containing water vapor. Since high-temperature air enters the suction fan, there is concern about deterioration of the durability performance due to temperature. Therefore, the arrangement of a fan and a duct for cooling the suction fan can be considered. Also, a separation fan and a separation duct for separating the sheet from a conveying member such as a conveying belt may be required.

[0007] Therefore, it is necessary to secure an arrangement space for a cooling mechanism of the suction fan and a separation mechanism of the sheet. However, in the conventional configuration, the layout for efficiently arranging these units has not been considered.

[0008] In view of the above problems, an object of the present invention is to provide a sheet drying device capable of arranging a cooling unit for a suction fan that sucks air containing water vapor and a unit for separating a sheet from a conveying member in a space-saving manner, and an image forming system including the same.

Means for Solving the Problems

[0009] In order to achieve the above object, a first configuration of the present invention is a sheet drying apparatus including a first conveyance unit, a drying unit, a suction fan, an exhaust unit, a first duct, a second duct, a separation fan, a separation duct, a cooling fan, and a cooling duct. The first conveyance unit conveys a sheet on which an image is formed with ink containing moisture. The drying unit is disposed opposite to the first conveyance unit and heats and dries the sheet. The suction fan sucks air containing water vapor present in a drying space between the first conveyance unit and the drying unit. The exhaust unit exhausts the air sucked by the suction fan. The first duct communicates the drying space and the suction fan. The second duct communicates the suction fan and the exhaust unit. The separation fan blows air onto the sheet conveyed by the first conveyance unit to separate the sheet from the first conveyance unit at a separation position. The separation duct communicates the separation fan and the separation position. The cooling fan blows outside air onto the suction fan to cool it. The cooling duct communicates the cooling fan and the suction fan. The suction fan and the second duct are disposed on the downstream side of the drying unit with respect to the conveyance direction of the sheet. The separation fan, the separation duct, the cooling fan, and the cooling duct are disposed on the downstream side of the suction fan and the second duct with respect to the conveyance direction. The separation duct and the cooling duct are disposed so as to partially overlap when viewed from a width direction perpendicular to the conveyance direction.

Effect of the Invention

[0010] According to the first configuration of the present invention, the separation fan, the separation duct, the cooling fan, and the cooling duct are disposed on the downstream side of the suction fan and the second duct, and the separation duct and the cooling duct are disposed so as to partially overlap when viewed from a width direction perpendicular to the conveyance direction. Thereby, the separation duct and the cooling duct can be arranged compactly, and space saving can be achieved.

Brief Description of the Drawings

[0011]

Figure 1

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Figure 13

Embodiments for Carrying Out the Invention

[0012] [1. Configuration of an Image Forming System including a Sheet Drying Device] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing the internal configuration of an image forming system 200 including the sheet drying device 10 of the present invention. FIG. 2 is a side cross-sectional view of the periphery of the drying section 40 of the sheet drying device 10 according to an embodiment of the present invention. With reference to FIGS. 1 and 2, an image forming system 200 including an image forming device 100 and a sheet drying device 10 will be described.

[0013] The image forming apparatus 100 is an inkjet recording type printer, and includes a paper feeding unit 2 disposed at the lower part of the image forming apparatus 100, an image forming unit 3 disposed above the paper feeding unit 2, and a paper feeding unit 4 that feeds the paper P accommodated in the paper feeding unit 2 to the image forming unit 3.

[0014] The image forming unit 3 is composed of a recording unit 3a having a plurality of recording heads and a printing conveyance unit 3b disposed opposite to the recording unit 3a. The printing conveyance unit 3b includes an endless printing conveyance belt 5 wound around a plurality of rollers including a driving roller. The paper P conveyed by the paper feeding unit 4 passes below the recording unit 3a while being adsorbed and held on the printing conveyance belt 5 by a paper suction unit (not shown) provided inside the printing conveyance belt 5. The paper P on which a predetermined image is recorded by the image forming unit 3 is discharged from the discharge roller pair 6 and carried into the sheet drying device 10.

[0015] The sheet drying device 10 is disposed adjacent to the image forming apparatus 100 and dries the ink on the paper P discharged from the image forming apparatus 100. The sheet drying device 10 includes a first conveyance unit 20, a preliminary drying unit 30, a drying unit 40, a suction fan unit 50, and a second conveyance unit 70.

[0016] The first conveyance unit 20 includes a driving roller 21a, a driven roller 21b, and a conveyance belt 22. The conveyance belt 22 is wound around the driving roller 21a disposed on the downstream side with respect to the conveyance direction of the paper P (from right to left in FIG. 1, hereinafter simply referred to as the conveyance direction) and the driven roller 21b disposed on the upstream side.

[0017] Paper suction parts 23a and 23b are disposed inside the conveyance belt 22. The conveyance belt 22 is formed with a number of suction holes (not shown) through which a suction air for adsorbing the paper P to the conveyance belt 22 by negative pressure suction by the paper suction parts 23a and 23b passes.

[0018] Belt cooling fans 24 are arranged at two locations below the conveyor belt 22. Also, a belt temperature sensor 25 is arranged in contact with and separated from the lower surface of the conveyor belt 22. The belt cooling fan 24 blows cooling air onto the conveyor belt 22 when the temperature detected by the belt temperature sensor 25 reaches a predetermined temperature or higher.

[0019] The preliminary drying unit 30 is arranged immediately downstream of the sheet inlet 61 in the conveying direction, and preliminarily dries the ink on the paper P conveyed from the sheet inlet 61. The preliminary drying unit 30 includes a paper blowing fan 31 and a paper blowing duct 32 for blowing air onto the paper P from above.

[0020] The drying unit 40 is arranged adjacent to the downstream side of the preliminary drying unit 30 in the conveying direction, and dries the ink on the paper P that has passed through the preliminary drying unit 30. The drying unit 40 includes two heating units 41 arranged so as to face the upper surface of the conveyor belt 22.

[0021] The suction fan unit 50 sucks the water vapor generated from the paper P passing through the drying unit 40. The suction fan unit 50 includes a suction fan 51 that sucks the air containing water vapor in the drying unit 40 and a separation fan 52 that blows separation air for separating the paper P from the conveyor belt 22. The suction fan unit 50 communicates with the space between the conveyor belt 22 and the heating unit 41 via the first duct 53 and communicates with the exhaust port 60 formed at the upper part of the sheet drying device 10 via the second duct 54. The detailed configuration of the suction fan unit 50 will be described later.

[0022] Also, a plurality of outside air introduction fans 63 for taking in outside air are arranged at appropriate positions inside the sheet drying device 10. Sheet detection sensors 64 and 65 are arranged at the upstream and downstream parts of the first conveying unit 20, respectively. The sheet detection sensors 64 and 65 detect that the paper P has passed through the sheet inlet 61 and the sheet outlet 62.

[0023] By the rotational drive of the drive roller 21a, the conveyor belt 22 rotates counterclockwise, so that the paper P carried in from the sheet inlet 61 sequentially passes through the preliminary drying section 30, the drying section 40, and the suction fan unit 50, and is discharged from the sheet outlet 62 to the outside of the sheet drying apparatus 10 or carried into the second conveying section 70.

[0024] The second conveying section 70 is disposed below the drying section 40 and the preliminary drying section 30 with the first conveying section 20 interposed therebetween. The second conveying section 70 includes a reversing conveyance path 70a for reversing the front and back surfaces of the paper P whose ink has been dried, and a duplex conveyance path 70b for returning the paper P whose front and back surfaces have been reversed to the image forming apparatus 100 when performing duplex printing on the paper P.

[0025] An arcuate retraction path 71 is provided on the downstream side (the left side in FIG. 1) of the suction fan unit 50 with respect to the conveyance direction. The retraction path 71 retracts and stocks the paper P (waste paper) that has become unnecessary due to printing defects or the like in the image forming apparatus 100.

[0026] [2. Configuration of Sheet Drying Apparatus] FIG. 3 is an enlarged view of the drying section 40 in FIG. 2. The drying section 40 includes a heating unit 41 and a warm air fan 42 (see FIG. 2). Two sets of heating units 41 are arranged along the conveyance direction (arrow X direction). The heating unit 41 includes a heater 43 and a reflector 44.

[0027] The heater 43 is rod-shaped and extends in the sheet width direction (the direction perpendicular to the paper surface of FIG. 3, hereinafter simply referred to as the width direction) that is perpendicular to the conveyance direction. A plurality (12 in this embodiment) of heaters 43 are arranged in parallel along the conveyance direction in the heating unit 41. In this embodiment, an infrared heater is used as the heater 43.

[0028] The reflector 44 is a U-shaped reflector in a side view that is arranged to surround each heater 43 from above. The infrared rays emitted from the heater 43 are reflected downward by the inner surface of the reflector 44 and irradiated onto the paper P carried and conveyed by the conveyor belt 22. As a result, the moisture in the ink on the paper P evaporates and dries, and the ink is fixed on the paper P.

[0029] The hot air fan 42 is arranged above the heating unit 41. More specifically, the hot air fan 42 is arranged to blow air upward toward the reflector 44. The air blown onto the reflector 44 by the hot air fan 42 is heated when passing through the gaps of each reflector 44 to become hot air, and flows into the gap (drying space) between the heating unit 41 and the conveyor belt 22.

[0030] If there is steam or water vapor in the gap between the heating unit 41 and the conveyor belt 22, the infrared rays emitted from the heater 43 and reflected by the reflector 44 will be absorbed by the steam or water vapor, and the drying ability of the ink on the paper P will be inhibited. Therefore, by blowing hot air into the gap between the heating unit 41 and the conveyor belt 22 by the hot air fan 42 to disperse and remove the steam or water vapor generated from the paper P, the drying property of the ink by the infrared rays can be maintained.

[0031] A first duct 53 for sucking the steam or water vapor generated from the paper P together with air is provided between the drying unit 40 and the suction fan unit 50. The first duct 53 is composed of a main body side first duct 53a and a unit side first duct 53b. The main body side first duct 53a extends from the gap between the heating unit 41 and the conveyor belt 22 to the suction fan unit 50. The unit side first duct 53b is provided in the suction fan unit 50 and communicates the main body side first duct 53a with the suction fan 51 in the suction fan unit 50.

[0032] FIG. 4 is a side cross-sectional view (a cross-sectional view taken along the arrow AA in FIG. 3) obtained by cutting the first conveying unit 20 and the drying unit 40 along the sheet width direction. FIG. 5 is a side cross-sectional view (a cross-sectional view taken along the arrow BB in FIG. 3) obtained by cutting the first conveying unit 20 and the suction fan unit 50 along the sheet width direction. FIG. 6 is a side cross-sectional view obtained by cutting the periphery of the suction fan unit 50 along the conveying direction. With reference to FIGS. 4 to 6, the exhaust path of the air containing the water vapor generated in the drying unit 40 will be described. The arrows in FIGS. 4 to 6 indicate the air flow.

[0033] The water vapor generated when drying the paper P exists in the drying space S between the heating unit 41 and the conveying belt 22. By rotationally driving the suction fan 51, as shown in FIG. 4, the air containing the water vapor in the drying space S is horizontally sucked into the main body side first duct 53a in the width direction from the front-rear direction (the direction of the arrow YY' in the figure) of the sheet drying apparatus 10.

[0034] As shown in FIGS. 5 and 6, the air that has passed through the main body side first duct 53a passes through the unit side first duct 53b of the suction fan unit 50 and is sucked by the suction fan 51. Above the suction fan 51, a second duct 54 that communicates the suction fan 51 and the exhaust port 60 is provided.

[0035] The second duct 54 is composed of a unit side second duct 54b and a main body side second duct 54a. The unit side second duct 54b extends upward from the suction fan 51 within the suction fan unit 50. The main body side second duct 54a communicates the unit side second duct 54b and the exhaust port 60. The air containing the water vapor sucked by the suction fan 51 sequentially passes through the unit side second duct 54b and the main body side second duct 54a, and is discharged to the outside of the sheet drying apparatus 10 from the exhaust port 60.

[0036] The air containing water vapor sucked by the suction fan 51 is cooled by mixing with outside air after passing through the second duct 54a on the main body side and before being discharged from the exhaust port 60, and condensation may occur. At this time, a storage portion 54c is formed in the second duct 54a on the main body side so that the water condensed on the inner wall surface of the second duct 54a on the main body side does not flow back to the suction fan 51. The storage portion 54c has a concave shape capable of storing liquid, and the water condensed on the inner wall surface of the second duct 54a on the main body side and flowing down is blocked by the storage portion 54c, and is configured not to flow back to the suction fan 51.

[0037] The suction fan unit 50 further includes a cooling fan 55 and a cooling duct 56. Two cooling fans 55 are provided in the suction fan unit 50, and outside air is blown to the suction fan 51 through the suction ducts 57a and 57b (see FIG. 9), respectively. Thereby, the suction fan 51 is cooled, and it is possible to suppress the suction fan 51 from becoming hot due to the air containing water vapor. In FIGS. 6 and 11 described later, the cooling fan 55 overlaps the separation fan 52.

[0038] [3. Configuration of Suction Fan Unit] FIG. 7 is a perspective view showing the periphery of the suction fan unit 50 in the sheet drying apparatus 10. FIG. 8 is a perspective view showing a state in the middle of removing the suction fan unit 50 from the state of FIG. 7. As shown in FIG. 8, the suction fan unit 50 can be attached to and detached from the main body of the sheet drying apparatus 10 in the horizontal direction.

[0039] More specifically, by removing the suction fan unit 50 in the horizontal direction, the first duct 53 is separated into a first duct 53a on the main body side and a first duct 53b on the unit side. The second duct 54 is separated into a second duct 54a on the main body side and a second duct 54b on the unit side. By removing the suction fan unit 50, it becomes possible to access the second duct 54a on the main body side, and thus the water accumulated in the storage portion 54c of the second duct 54a on the main body side can be removed.

[0040] FIG. 9 is a perspective view of the suction fan unit 50. FIGS. 10 and 11 are a cross-sectional perspective view and a side cross-sectional view of the suction fan unit 50 cut at a portion including the separation fan 52, respectively. The suction fan unit 50 includes a suction fan 51, a separation fan 52, a unit-side first duct 53a, a unit-side second duct 54a, a cooling fan 55, a cooling duct 56, suction ducts 57a to 57c, and a separation duct 58.

[0041] As shown in FIGS. 9 and 10, the separation fan 52 is disposed between the two cooling fans 55. The separation fan 52 communicates with the suction duct 57c and the separation duct 58, sucks outside air through the suction duct 57c, and blows it into the separation duct 58. The light receiving portion 65b of the sheet detection sensor 65 is disposed in the separation duct 58.

[0042] FIG. 12 is a side cross-sectional view of the suction fan unit 50 and the periphery of the sheet discharge port 62 cut along the conveyance direction. At the transfer portion of the sheet P from the conveyance belt 22 to the sheet discharge port 62, a separation mechanism for separating the sheet P from the conveyance belt 22 is required. The air that has passed through the separation duct 58 is blown onto the upper surface of the sheet P from the separation air blowing port 58a at the downstream end (separation position R) of the conveyance belt 22. As a result, the upper portion of the sheet P is in a negative pressure (depressurized) state, and the sheet P can be easily separated from the conveyance belt 22.

[0043] Also, the light emitting portion 65a of the sheet detection sensor 65 is disposed below the sheet discharge port 62 on the downstream side (the left side in FIG. 12) of the conveyance unit 22 with respect to the conveyance direction. The sheet detection sensor 65 is an optical sensor in which the light emitting portion 65a and the light receiving portion 65b are separated. When a jam (paper clogging) of the sheet P occurs between the conveyance belt 22 and the sheet discharge port 62, the optical path (indicated by the dotted arrow in FIG. 12) between the light emitting portion 65a and the light receiving portion 65b remains blocked by the sheet P. Thereby, it is possible to detect a jam of the sheet P.

[0044] Further, by providing the light receiving portion 65b of the sheet detection sensor 65 in the separation duct 58, it is possible to prevent the light receiving portion 65b from becoming high temperature due to the heat of the drying unit 40. As a result, thermal degradation and failure of the light receiving portion 65b are less likely to occur.

[0045] In addition, the arrangement of the light emitting portion 65a and the light receiving portion 65b of the sheet detection sensor 65 can be swapped, and the light emitting portion 65a can also be provided in the separation duct 58. However, when the light receiving portion 65b is arranged outside the separation duct 58, there is a possibility of false detection due to the infrared rays emitted from the heater 43 of the drying unit 40 entering the light receiving portion 65b. Therefore, the configuration of the present embodiment in which the light receiving portion 65b is arranged in the separation duct 58 is preferable.

[0046] According to the configuration of the present embodiment, a separation fan 52, a separation duct 58, a cooling fan 55, and a cooling duct 56 are arranged on the downstream side of the suction fan 51 and the second duct 54, and the separation duct 58 and the cooling duct 56 are arranged so that at least a part of them overlaps when viewed in the width direction. Thereby, the separation duct 58 and the cooling duct 56 can be arranged compactly.

[0047] Further, the separation fan 52 and the cooling fan 55 used for separating the sheet P from the conveyor belt 22 are arranged in parallel along the width direction perpendicular to the conveyance direction, and the cooling duct 56 extends from the cooling fan 55 toward the suction fan 51. As a result, since the cooling duct 56 and the separation duct 58 are arranged in parallel along the width direction, more space can be saved.

[0048] In addition, a suction fan unit 50 in which the suction fan 51, the separation fan 52, the cooling fan 55, the cooling duct 56, and the separation duct 58 are unitized is provided, and it is made horizontally detachable from the main body of the sheet drying device 10, so that the detachability of the suction fan unit 50 is improved, and unit replacement and maintenance time can be shortened.

[0049] Further, by providing the preliminary drying unit 30 upstream of the drying unit 40, when the paper P passes through the preliminary drying unit 30, the paper P is preheated to a predetermined temperature, so that a rapid temperature change of the paper P and the ink by the drying unit 40 can be suppressed.

[0050] Also, by arranging the second conveying unit 70 with the first conveying unit 20 interposed therebelow of the drying unit 40, it becomes difficult for the hot air of the drying unit 40 to be transmitted to the second conveying unit 70, so that it is possible to suppress the paper P conveyed by the second conveying unit 70 from becoming high temperature.

[0051] Furthermore, by arranging the light receiving part 65b of the sheet detection sensor 65 in the separation duct 58, since the light receiving part 65b is always cooled by the air flow, it is possible to arrange the light receiving part 65b even in the vicinity of the drying unit 40 that becomes high temperature.

[0052] In addition, the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention. For example, in the above-described embodiment, the light receiving part 65b of the sheet detection sensor 65 is arranged in the separation duct 58, but it is also possible to arrange electronic components other than the sheet detection sensor 65 in the separation duct 58.

[0053] For example, as shown in FIG. 13, when a separation air adjustment guide 58b is provided at the separation air blowing port 58a of the separation duct 58 so that the opening width and the opening direction of the separation air blowing port 58a can be adjusted, a guide drive motor 59 for swinging the separation air adjustment guide 58b is arranged in the separation duct 58. Thereby, thermal degradation of the guide drive motor 59 can be suppressed.

[0054] Also, in the above-described embodiment, as an example of the image forming system 200, a configuration in which the sheet drying device 10 is connected to the image forming device 100 which is an inkjet printer is shown, but it goes without saying that the sheet drying device 10 can be used independently without being connected to the image forming device 100.

Industrial Applicability

[0055] The present invention can be used in a sheet drying device for drying a sheet on which an image is printed by an inkjet recording device or the like. By using the present invention, it is possible to provide a sheet drying device in which a cooling unit of a suction fan for sucking air containing water vapor and a unit for separating a sheet from a conveying member can be arranged in a space-saving manner, and an image forming system including the same.

Explanation of Signs

[0056] 10 Sheet drying device 20 First conveying unit 30 Pre-drying unit 40 Drying unit 50 Suction fan unit 51 Suction fan 52 Separation fan 53 First duct 53a Main body side first duct 53b Unit side first duct 54 Second duct 54a Main body side second duct 54b Unit side second duct 55 Cooling fan 56 Cooling duct 57a~57c Suction ducts 58 Separation duct 59 Guide drive motor 60 Exhaust port 61 Sheet inlet 62 Sheet outlet 64, 65 Sheet detection sensors 65a Light emitting part 65b Light receiving part 70 Second conveying unit 70a Inversion conveying path 70b Double-sided conveying path 71 Retraction path 100 Image forming device 200 Image forming system P Paper (sheet)

Claims

1. A first conveying unit that conveys a sheet on which an image is formed by ink containing moisture; A drying unit that is disposed opposite to the first conveying unit and heats and dries the sheet; A suction fan that sucks air containing water vapor present in a drying space between the first conveying unit and the drying unit; An exhaust unit that exhausts the air sucked by the suction fan; A first duct that communicates the drying space and the suction fan; A second duct that communicates the suction fan and the exhaust unit; In a sheet drying device comprising: The suction fan and the second duct are disposed on the downstream side of the drying unit with respect to the conveying direction of the sheet; On the downstream side of the suction fan and the second duct with respect to the conveying direction, A separation fan that blows air to the sheet conveyed by the first conveying unit to separate the sheet from the first conveying unit at a separation position; A separation duct that communicates the separation fan and the separation position; A cooling fan that blows outside air to the suction fan for cooling; A cooling duct that communicates the cooling fan and the suction fan; Are arranged, The sheet drying device, wherein the separation duct and the cooling duct are arranged so that at least a part thereof overlaps when viewed from a width direction perpendicular to the conveying direction horizontally.

2. The sheet drying device according to claim 1, wherein the separation fan and the cooling fan are arranged in parallel along the width direction.

3. The suction fan constitutes a suction fan unit together with the separation fan, the separation duct, the cooling fan, and the cooling duct, The sheet drying device according to claim 1, wherein the suction fan unit is detachable from the sheet drying device main body.

4. The sheet drying device according to claim 3, wherein an arc-shaped retracting path for retracting and stocking the unnecessary sheet is provided on the downstream side of the suction fan unit with respect to the conveying direction.

5. The sheet drying device according to claim 1, wherein a preliminary drying unit for preliminarily drying the sheet is disposed on the upstream side of the drying unit with respect to the conveying direction.

6. A second conveying unit is disposed below the drying unit with the first conveying unit interposed therebetween, The second conveying unit, A reversing conveyance path for reversing the front and back surfaces of the sheet, When performing double-sided printing on the sheet, a double-sided conveyance path for returning the sheet with the front and back sides reversed to the image forming apparatus, The sheet drying device according to claim 1, characterized by having

7. The sheet drying device according to claim 1, characterized in that an electronic component is arranged in the separation duct.

8. Provided on the downstream side of the first conveyance unit with respect to the conveyance direction, and having a sheet discharge port for discharging the sheet, On the downstream side of the first conveyance unit with respect to the conveyance direction and on the upstream side of the sheet discharge port, there is a sheet detection sensor having a light emitting unit and a light receiving unit for detecting the sheet, The sheet drying device according to claim 7, characterized in that either the light emitting unit or the light receiving unit as the electronic component is arranged in the separation duct.

9. The drying unit includes a heating unit having a plurality of infrared heaters arranged opposite to the first conveyance unit, The sheet drying device according to claim 8, characterized in that the light receiving unit is arranged in the separation duct as the electronic component.

10. An image forming apparatus that performs image formation using ink containing moisture on a sheet, The sheet drying device according to any one of claims 1 to 9 for drying the sheet on which an image is formed by the image forming apparatus, An image forming system comprising

Images