Sheet drying apparatus and image forming system including the same

Abstract

To provide a sheet drying apparatus which can efficiently suction air in the apparatus containing steam and suppress influence on conveyance of a sheet, and to provide an image forming system including the sheet drying apparatus.SOLUTION: A sheet drying apparatus includes a conveyance portion, a drying portion, a suction fan unit, an exhaust portion, a first duct, and a second duct. The conveyance portion conveys a sheet on which an image is formed with inks containing moisture. The drying portion heats and dries the sheet. The suction fan unit is arranged downstream of the drying portion in a conveyance direction of the sheet and has a suction fan that sucks in air present in a drying space between the conveyance portion and the drying portion. The exhaust portion discharges the air sucked in by the suction fan unit. The first duct allows communication between the drying space with the suction fan. The second duct allows communication between the suction fan and the exhaust portion. The suction fan unit collects the air present in the drying space by sucking it in a horizontal direction orthogonal to the conveyance direction via the first duct.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, Patent Document 1 discloses a drying device including a heating unit that heats a continuous accounting paper to which a liquid is applied in a liquid applying unit, a cooling unit that cools the continuous accounting paper heated in the heating unit, a cooling unit that supplies a circulating liquid cooled in the cooling unit, a first duct that guides steam generated in the heating unit, and a recovery path through which the circulating liquid flows.

[0004] Patent Document 2 discloses a drying device including a heating unit that heats an object to which a liquid has adhered, and a dew condensation water recovery unit that is disposed so as to surround the heating unit and recovers dew condensation water generated from the object by steam generated by the heating unit, the dew condensation water recovery unit including an opening variable unit that varies an opening state of an outside air intake through which outside air is taken in.

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, an increase in the replacement frequency is considered. However, in the conventional configuration, since the suction fan is fixed to the device, there is a problem that it takes time to replace the suction fan.

[0007] In addition, the duct for exhausting the air containing water vapor generated in the heating section is configured to suck from the conveyance path in the height direction, and there is a problem that the sheet is lifted from the conveyance path when the suction performance is improved.

[0008] In view of the above problems, an object of the present invention is to provide a sheet drying device that can efficiently suck air inside the device containing water vapor and can also suppress the influence on the conveyance of the sheet, and an image forming system including the same.

Means for Solving the Problems

[0009] To achieve the above object, a first configuration of the present invention is a sheet drying device including a conveyance section, a drying section, a suction fan unit, an exhaust section, a first duct, and a second duct. The conveyance section conveys a sheet on which an image is formed with ink containing moisture. The drying section is disposed opposite to the conveyance section and heats and dries the sheet. The suction fan unit is disposed on the downstream side of the drying section with respect to the conveyance direction of the sheet, and has a suction fan that sucks air containing water vapor present in the drying space between the conveyance section and the drying section. The exhaust section exhausts the air sucked by the suction fan unit. The first duct communicates the drying space and the suction fan. The second duct communicates the suction fan and the exhaust section. The suction fan unit sucks and collects the air present in the drying space in a horizontal direction orthogonal to the conveyance direction through the first duct.

Effects of the Invention

[0010] According to the first configuration of the present invention, by sucking air containing water vapor present in the drying space in a horizontal direction orthogonal to the conveyance direction through the first duct, while minimizing the influence of the suction on the conveyance of the sheet as much as possible, the air containing water vapor can be efficiently exhausted with a compact configuration.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 6

Figure 7

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Figure 9

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Figure 12

Figure 13

Embodiments for Carrying Out the Invention

[0012] [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 around the drying unit 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 composed of an image forming device 100 and a sheet drying device 10 will be described.

[0013] The image forming device 100 is an inkjet recording type printer, and includes a paper feeding unit 2 disposed below the image forming device 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 device 100 and dries the ink on the paper P discharged from the image forming device 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 conveying unit 20 includes a driving roller 21a, a driven roller 21b, and a conveyor belt 22. The conveyor belt 22 is looped around the driving roller 21a disposed on the downstream side with respect to the conveying direction of the sheet P (from right to left in FIG. 1, hereinafter simply referred to as the conveying direction) and the driven roller 21b disposed on the upstream side.

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

[0018] Belt cooling fans 24 are disposed at two positions below the conveyor belt 22. Also, a belt temperature sensor 25 is disposed in contact with and separated from the lower surface of the conveyor belt 22. The belt cooling fans 24 blow cooling air to the conveyor belt 22 when the detected temperature of the belt temperature sensor 25 becomes equal to or higher than a predetermined temperature.

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

[0020] The drying unit 40 is disposed adjacent to the downstream side of the preliminary drying unit 30 with respect to the conveying direction, and dries the ink on the sheet P that has passed through the preliminary drying unit 30. The drying unit 40 includes two heating units 41 disposed 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 a separation air flow for separating the paper P from the conveyance belt 22. The suction fan unit 50 communicates with the space between the conveyance belt 22 and the heating unit 41 via a first duct 53, and communicates with an exhaust port 60 formed at the upper part of the sheet drying device 10 via a 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 conveyance 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 causing the conveyance belt 22 to rotate counterclockwise, the paper P carried in from the sheet inlet 61 sequentially passes through the preliminary drying unit 30 and the drying unit 40, and is discharged to the outside of the sheet drying device 10 from the sheet outlet 62, or is carried into the second conveyance unit 70.

[0024] The second conveyance unit 70 is arranged below the drying unit 40 and the preliminary drying unit 30 with the first conveyance unit 20 interposed therebetween. The second conveyance unit 70 includes a reverse conveyance path 70a for inverting 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 with its front and back surfaces inverted 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 Device] Figure 3 is an enlarged view of the drying unit 40 in Figure 2. The drying unit 40 includes a heating unit 41 and a warm air fan 42 (see Figure 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 plane of Figure 3, hereinafter simply referred to as the width direction) that is horizontally orthogonal 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 side-view U-shaped reflector plate 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 sheet P carried and conveyed by the conveyance belt 22. Thereby, the moisture in the ink on the sheet P evaporates and dries, and the ink is fixed on the sheet P.

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

[0030] If steam or water vapor exists in the gap between the heating unit 41 and the conveyance 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 sheet P will be inhibited. Therefore, by blowing warm air into the gap between the heating unit 41 and the conveyance belt 22 by the warm air fan 42 to disperse and remove the steam or water vapor generated from the sheet P, the drying property of the ink by infrared rays can be maintained.

[0031] A first duct 53 for sucking steam and water vapor generated from the sheet P together with air is provided between the drying section 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 line AA in FIG. 3) obtained by cutting the first conveying section 20 and the drying section 40 along the sheet width direction. FIG. 5 is a side cross-sectional view (a cross-sectional view taken along the line BB in FIG. 3) obtained by cutting the first conveying section 20 and the suction fan unit 50 along the sheet width direction. FIG. 6 is a side cross-sectional view obtained by cutting around the suction fan unit 50 along the conveying direction. The discharge path of the air containing the water vapor generated in the drying section 40 will be described with reference to FIGS. 4 to 6. The arrows in FIGS. 4 to 6 indicate the air flow.

[0033] The water vapor generated when drying the sheet P exists in the drying space S between the heating unit 41 and the conveyor 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 with 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 with the exhaust port 60. The air containing 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 device 10 through the exhaust port 60.

[0036] The air containing water vapor sucked by the suction fan 51 may be cooled by mixing with the outside air after passing through the main body-side second duct 54a and before being discharged from the exhaust port 60, resulting in condensation. At this time, a storage portion 54c is formed in the main body-side second duct 54a so that the water condensed on the inner wall surface of the main body-side second duct 54a 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 main body-side second duct 54a and flowing down is blocked by the storage portion 54c, preventing it from flowing 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 each blows outside air to the suction fan 51 through suction ducts 57a, 57b (see FIG. 9). Thereby, the suction fan 51 is cooled, suppressing 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 within the sheet drying device 10. FIG. 8 is a perspective view showing a state in the middle of removing the suction fan unit 50 from the state shown in 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 device 10 in the horizontal direction.

[0039] More specifically, by horizontally removing the suction fan unit 50, the first duct 53 is separated into a main body side first duct 53a and a unit side first duct 53b. The second duct 54 is separated into a main body side second duct 54a and a unit side second duct 54b. By removing the suction fan unit 50, it becomes possible to access the main body side second duct 54a, so that the water accumulated in the storage portion 54c of the main body side second duct 54a 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. A 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, on the downstream side of the transport unit 22 (the left side in FIG. 12) with respect to the transport direction and below the sheet discharge port 62, a light emitting unit 65a of a sheet detection sensor 65 is disposed. The sheet detection sensor 65 is an optical sensor in which the light emitting unit 65a and the light receiving unit 65b are separated. When a jam (paper clogging) of the sheet P occurs between the transport belt 22 and the sheet discharge port 62, the optical path (indicated by the dotted arrow in FIG. 12) between the light emitting unit 65a and the light receiving unit 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 unit 65b of the sheet detection sensor 65 in the separation duct 58, it is possible to prevent the light receiving unit 65b from becoming high temperature due to the heat of the drying unit 40. As a result, it is difficult for thermal degradation or failure of the light receiving unit 65b to occur.

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

[0046] According to the configuration of the present embodiment, the air in the drying space S between the heating unit 41 of the drying unit 40 and the transport belt 22 of the first transport unit 20 can be sucked in a horizontal direction orthogonal to the transport direction via the first duct 53. Thereby, while minimizing the influence of the suction on the transport of the sheet P as much as possible, the air containing water vapor can be efficiently exhausted with a compact configuration.

[0047] Also, by providing a suction fan unit 50 in which the suction fan 51, the unit side first duct 53b, and the unit side second duct 54b are unitized and making it horizontally detachable from the main body of the sheet drying device 10, the detachability of the suction fan unit 50 is improved, and unit replacement and maintenance time can be shortened.

[0048] Further, by providing the storage portion 54c in the main body side second duct, it is possible to prevent the condensed water in the second duct 54 from flowing back to the suction fan 51. Further, when the suction fan unit 50 is removed, the storage portion 54c is exposed, so that the water condensed in the second duct 54 and accumulated in the storage portion 54c can be easily removed.

[0049] Furthermore, by providing the separation fan 52 and the separation duct 58 in the suction fan unit 50 and arranging the light receiving portion 65b of the sheet detection sensor 65 in the separation duct 58, the light receiving portion 65b is always cooled by the air flow, so that the light receiving portion 65b can be arranged even in the vicinity of the drying portion 40 that becomes hot.

[0050] In addition, the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, in the above-described embodiment, the light receiving portion 65b of the sheet detection sensor 65 is arranged in the separation duct 58, but electronic components other than the sheet detection sensor 65 can also be arranged in the separation duct 58.

[0051] 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, the thermal deterioration of the guide drive motor 59 can be suppressed.

[0052] In addition, 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 apparatus 100 which is an inkjet printer is shown. However, it goes without saying that the sheet drying device 10 can be used independently without being connected to the image forming apparatus 100.

Industrial Applicability

[0053] The present invention can be used in a sheet drying device that dries 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 that improves the attachment / detachment performance of a suction fan and suppresses the influence on the conveyance of the sheet, and an image forming system including the same.

Explanation of Signs

[0054] 10 Sheet drying device 20 First conveyance unit (conveyance unit) 30 Preliminary 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 54c Storage part 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 conveyance unit 100 Image forming apparatus 200 Image forming system P Paper (sheet)

Claims

1. A 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 conveying unit and heats and dries the sheet; A suction fan unit that is disposed on the downstream side of the drying unit with respect to the conveying direction of the sheet and has a suction fan that sucks air containing water vapor present in the drying space between the conveying unit and the drying unit; An exhaust unit that exhausts the air sucked by the suction fan unit; 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 unit is characterized in that it sucks and collects the air present in the drying space in a horizontal direction perpendicular to the conveying direction through the first duct. A sheet drying device.

2. The first duct is: A main body side first duct fixed to the sheet drying device main body; A unit side first duct fixed to the suction fan unit; Composed of; The second duct is: A main body side second duct fixed to the sheet drying device main body; A unit side second duct fixed to the suction fan unit; Composed of, When the suction fan unit is removed from the sheet drying device main body, the main body side first duct and the unit side first duct, and the main body side second duct and the unit side second duct are separated. The sheet drying device according to claim 1.

3. The second duct extends upward from the suction fan toward the exhaust unit, The main body side second duct has a storage unit for storing water generated by condensation of the water vapor. The sheet drying device according to claim 2.

4. The suction fan unit is: A separation fan that blows air onto the sheet conveyed by the conveying unit to separate the sheet from the conveying unit at a separation position; A separation duct that communicates the separation fan and the separation position; Comprising, An electronic component is disposed in the separation duct. The sheet drying device according to claim 1.

5. Provided on the downstream side of the conveying unit with respect to the conveying direction, and having a sheet discharge port for discharging the sheet, On the downstream side of the conveying unit with respect to the conveying direction and on the upstream side of the sheet discharge port, there are a light emitting unit and a light receiving unit, and a sheet detection sensor for detecting the sheet is disposed. The sheet drying device according to claim 4, wherein either the light emitting part or the light receiving part is arranged as the electronic component in the separation duct.

6. The drying part includes a heating unit having a plurality of infrared heaters arranged to face the conveying part. The sheet drying device according to claim 5, wherein the light receiving part is arranged as the electronic component in the separation duct.

7. The suction fan unit includes a cooling fan that blows outside air to the suction fan for cooling, and a cooling duct that communicates the cooling fan and the suction fan. The sheet drying device according to claim 1, characterized by comprising the above.

8. An image forming apparatus that forms an image using ink containing moisture on a sheet, and the sheet drying device according to any one of claims 1 to 7 that dries the sheet on which the image is formed by the image forming apparatus. An image forming system comprising the above.

Images