Drying device and image forming system

Abstract

To determine the presence or absence of a sheet in a section where a heater of a conveyance path is provided.SOLUTION: The drying device includes a conveyance device configured to convey the sheet along a conveyance path, a heater provided in a predetermined section of the conveyance path, a first sensor provided upstream of the heater in a conveyance direction of the sheet and configured to detect the sheet, a second sensor provided downstream of the heater in the conveyance direction and configured to detect the sheet, and a determination unit configured to determine presence or absence of the sheet in the predetermined section based on a detection result of the first sensor and a detection result of the second sensor.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a drying device and an image forming system. [Background technology]

[0002] When forming an image using an inkjet method, it is necessary to quickly dry the ink ejected onto the sheet to prevent image distortion, deformation or sticking of the sheet, etc. As a means for drying the ink, a drying device that heats the conveyed sheet with an infrared heater is known (for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-54503 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-46522 Summary of the Invention [Problem to be solved by the invention]

[0004] When printing on single sheets in the above configuration, it is necessary to determine whether or not a sheet is present in the section where the heater is located in order to perform control to prevent excessive heating of sheets that have become stuck in the transport path.However, because sensors are sensitive to heat, it is difficult to place sensors in the section where the heater is located.

[0005] Furthermore, applying a large amount of heat to the ink on the sheet in a short period of time will cause the water in the ink to boil, distorting the image, so heat must be applied over a certain period of time. However, stopping the sheet under the heater or slowing down the conveyance speed will impair high-speed printing. Therefore, it is necessary to lengthen the section where the heater is installed, but when printing multiple sheets continuously, there is a possibility that multiple sheets will be present in this section, so control must be performed according to the number of sheets.

[0006] In consideration of the above circumstances, an object of the present invention is to determine whether a sheet is present in a section of a conveying path where a heater is provided. [Means for solving the problem]

[0007] In order to solve the above problem, the device of the present invention comprises a conveying device that conveys a sheet along a conveying path, a heater provided in a predetermined section of the conveying path, a first sensor that is provided upstream of the heater in the sheet conveying direction and detects the sheet, a second sensor that is provided downstream of the heater in the conveying direction and detects the sheet, and a determination unit that determines the presence or absence of a sheet in the predetermined section based on the detection results by the first sensor and the detection results by the second sensor.

[0008] The drying device may be provided with a control unit that controls the drying device, and the control unit may control the conveying device to discharge the sheet from the specified section to the downstream side in the conveying direction when an abnormality occurs in an image forming system including the drying device.

[0009] The determination unit may calculate the number of sheets present in the specified section from the number of times the sheet is detected by the first sensor and the number of times the sheet is detected by the second sensor, and the control unit may drive the conveying device until all sheets are discharged from the specified section.

[0010] When the sheet cannot be discharged downstream of the specified section in the conveying direction, the control unit may stop the conveying device and the heater, and after the temperature of the heater drops to a specified temperature, output information urging the removal of the sheet.

[0011] The drying device may be provided with an evacuation path branching off from the conveying path, and the control unit may cause the sheet to evacuate into the evacuation path when it is not possible to discharge the sheet downstream in the conveying direction from the specified section.

[0012] The drying device may be provided with an evacuation path branching off from the conveying path, and the control unit may stop the conveying device and the heater when the number of sheets present in the specified section exceeds the number that can be evacuated to the evacuation path, and output information prompting the removal of the sheets after the temperature of the heater has dropped to a specified temperature.

[0013] The control unit may stop the conveying device and the heater after evacuating the number of sheets that can be evacuated to the evacuation path, and output information prompting the removal of the sheets after the temperature of the heater has dropped to the predetermined temperature.

[0014] The control unit may output information indicating the number of sheets present in the predetermined section.

[0015] The drying device may include a moving device that moves the heater closer to and away from the conveying path, and the control unit may control the moving device to move the heater away from the conveying path when stopping the heater.

[0016] An image forming system according to the present invention includes an inkjet recording device and a drying device that dries ink ejected onto a sheet by the inkjet recording device. [Effects of the Invention]

[0017] According to the present invention, it is possible to determine whether or not a sheet is present in a section of the conveying path where a heater is provided. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a front view schematically illustrating an internal configuration of an image forming system according to an embodiment of the present invention. [Figure 2] 1 is a front view schematically showing the internal configuration of a drying device according to an embodiment of the present invention. [Figure 3] 1 is a perspective view showing a moving device according to an embodiment of the present invention; [Figure 4]1 is a perspective view showing a moving device according to an embodiment of the present invention; [Figure 5] 10 is a flowchart showing a control procedure when an abnormality occurs in the image forming system according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] An image forming system 100 according to an embodiment of the present invention will be described below with reference to the drawings.

[0020] Fig. 1 is a front view showing a schematic internal configuration of image forming system 100. In the following description, the front side of the paper in Fig. 1 is the front side (front side) of image forming system 100, and left and right directions are described based on the direction when image forming system 100 is viewed from the front. In each figure, U, Lo, L, R, Fr, and Rr represent up, down, left, right, front, and rear, respectively.

[0021] The image forming system 100 includes a paper feeder 110, an inkjet recording apparatus 1, a drying apparatus 120, and a post-processing apparatus 130. The paper feeder 110 stores sheets S and supplies the sheets S to the inkjet recording apparatus 1. The inkjet recording apparatus 1 forms an image on the sheets S using an inkjet method. The drying apparatus 120 heats the sheets S transported from the inkjet recording apparatus 1 to dry the ink. The post-processing apparatus 130 performs post-processing such as stacking, stapling, folding, and punching holes on the sheets S transported from the drying apparatus 120.

[0022] The sheet feeding device 110 includes a sheet feeding cassette 4, a sheet feeding roller 5, a conveying path 10A, a sheet aligning device 6, and an evacuation tray 9. The sheet feeding cassette 4 stores stacked sheets S. The sheet feeding roller 5 sends the sheets S one by one from the sheet feeding cassette 4 to the conveying path 10A. Two sheet aligning devices 6, each having the same basic configuration, are arranged one above the other. The sheet aligning devices 6 have the function of correcting the inclination of the sheet S with respect to the conveying direction Y and the function of correcting the positional deviation of the sheet S in the width direction X that intersects with the conveying direction Y. The conveying path 10A leads to the sheet aligning device 6 on the lower side. The conveying path 10B branches off from the conveying path 10A and leads to the sheet aligning device 6 on the upper side. The conveying path 10C branches off from the conveying path 10B and leads to the evacuation tray 9. Conveying rollers 17 for conveying the sheet S are provided in the conveying paths 10A, 10B, and 10C.

[0023] At the branch point between conveying paths 10A and 10B, there is provided an opening / closing member 8A that swings about an axis to open either conveying path 10A or conveying path 10B and close the other. When opening / closing member 8A opens conveying path 10A, sheet S is guided into conveying path 10A, and when opening / closing member 8B opens conveying path 10B, sheet S is guided into conveying path 10B.

[0024] At the branch point between conveying path 10B and conveying path 10C, there is provided an opening / closing member 8B that swings about an axis to open one of conveying path 10B and conveying path 10C and close the other. When opening / closing member 8B opens conveying path 10B, sheet S is guided to conveying path 10B, and when opening / closing member 8B opens conveying path 10C, sheet S is guided to conveying path 10C.

[0025] The inkjet recording apparatus 1 includes a conveying device 7 that adsorbs a sheet S and conveys it in a predetermined conveying direction Y. Four head units 11 that eject ink to form an image are provided above the conveying device 7. The inkjet recording apparatus 1 includes a conveying path 10D that conveys the sheet S along the gap between the conveying device 7 and the head units 11. Conveying paths 10A and 10B merge into conveying path 10D.

[0026] The conveying device 7 includes an endless conveying belt 21 and a suction unit 24. The conveying belt 21 has a number of air holes (not shown) and is wound around a driving roller 25 and a driven roller 22. The upper surface of the suction unit 24 has a number of air holes (not shown) and is in contact with the inner surface of the conveying belt 21. The suction unit 24 sucks air through the air holes of the conveying belt 21 and the suction unit 24, thereby adsorbing the sheet S to the conveying belt 21. The drive roller 25 is driven counterclockwise by a drive unit (not shown) including a motor and a reduction gear, causing the conveying belt 21 to rotate counterclockwise, and the sheet S adsorbed to the conveying belt 21 is conveyed in the Y direction.

[0027] Each head unit 11 includes one or more inkjet heads 12. An ink container 20 filled with black, cyan, magenta, or yellow ink is connected to each head unit 11. The four head units 11 are arranged spaced apart from one another, and a maintenance unit 13 that performs maintenance on the inkjet heads 12 is provided to the right of each head unit 11.

[0028] The control unit 2 (see FIG. 1) includes a calculation unit and a storage unit (not shown). The calculation unit is, for example, a CPU (Central Processing Unit). The storage unit includes storage media such as a ROM (Read Only Memory), a RAM (Random Access Memory), and an EEPROM (Electrically Erasable Programmable Read Only Memory). The calculation unit controls each unit of the image forming system 100 by reading and executing a control program stored in the storage unit. The control unit 2 may also be realized by an integrated circuit without using software.

[0029] The display operation unit 19 includes a display panel, a touch panel laminated on the display panel, and a keypad (not shown). The control unit 2 displays a screen showing the operation menu and status of the inkjet recording apparatus 1 on the display panel, and controls each part of the inkjet recording apparatus 1 in response to operations detected by the touch panel and the keypad.

[0030] [Drying equipment] 2 is a front view showing a schematic internal configuration of the drying device 120. The drying device 120 has a rectangular parallelepiped main body housing 39. The main body housing 39 is provided with a conveying device 50 and a heater 80. The conveying device 50 conveys the sheet S conveyed from the inkjet recording apparatus 1 by adsorbing it onto an endless conveying belt 51. The heater 80 dries the ink on the sheet S conveyed by the conveying device 50.

[0031] [Transportation equipment] The conveying device 50 includes an endless conveying belt 51 and a suction unit 54. The conveying belt 51 has a number of air holes (not shown) and is wound around a driving roller 55 and a driven roller 52. The upper surface of the suction unit 54 has a number of air holes (not shown) and is in contact with the inner surface of the conveying belt 51. The suction unit 54 sucks air through the air holes of the conveying belt 51 and the suction unit 54, thereby adsorbing the sheet S to the conveying belt 51. The drive roller 55 is driven counterclockwise by a drive unit (not shown) including a motor and a reduction gear, causing the conveying belt 51 to rotate counterclockwise, and the sheet S adsorbed to the conveying belt 51 is conveyed in the Y direction.

[0032] [Heater] The heater 80 faces the conveyor belt 51. A plurality of heaters 80 (four in this embodiment) are arranged along the conveyance direction Y. The heater 80 has a main body housing 81 with an opening in a portion corresponding to the bottom of a rectangular parallelepiped. The main body housing 81 is provided with an infrared heater 82 and a reflector 83. The infrared heater 82 is formed in a rod shape with its longitudinal direction being the width direction X (front-rear direction) that intersects with the conveyance direction Y. A plurality of infrared heaters 82 (six in this embodiment) are arranged along the conveyance direction Y. The infrared heater 82 is, for example, a carbon heater (not shown) in which a heating element made of carbon fiber is enclosed in a glass tube. The heating element radiates infrared rays. The heater 80 is provided with a sensor 84 that measures the temperature of the heater 80.

[0033] A reflector 83 is provided above each infrared heater 82. The reflector 83 is formed, for example, in the shape of an upwardly convex parabola in cross section perpendicular to the width direction X. The reflector 83 reflects infrared rays emitted from the infrared heaters 82 downward.

[0034] [Transport path] The drying device 120 includes a conveying path 10E that conveys the sheet S along the gap between the conveying device 50 and the heater 80. The conveying path 10E is connected to a conveying path 10D of the inkjet recording device 1 and a conveying path 10U of the post-processing device 130.

[0035] Conveying path 10F branches downward from conveying path 10E. Conveying path 10F branches into conveying path 10G and conveying path 10J. Conveying path 10G and conveying path 10J are curved in an arc. Conveying path 10H branches right from conveying path 10G, and conveying path 10K branches right from conveying path 10J. Conveying path 10H and conveying path 10K merge into conveying path 10M. Conveying path 10L branches downward from conveying path 10M, passes below conveying paths 10J, 10G, and 10F, and merges with conveying path 10E. Retracting path 10Q branches upward from conveying path 10E between the start point of conveying path 10F and the end point of conveying path 10L. Conveying paths 10E to 10M and retracting path 10Q are provided with conveying rollers 17 that convey the sheet S.

[0036] At the branch point between conveying path 10E and conveying path 10F, there is provided an opening / closing member 8C that swings about an axis to open one of conveying path 10E and conveying path 10F and close the other. When opening / closing member 8C opens conveying path 10E, sheet S is guided into conveying path 10E, and when opening / closing member 8C opens conveying path 10F, sheet S is guided into conveying path 10F.

[0037] At the branch point between conveying path 10G and conveying path 10K, there is provided an opening / closing member 8D that swings about an axis to open one of conveying path 10G and conveying path 10K and close the other. When opening / closing member 8D opens conveying path 10G, sheet S is guided into conveying path 10G, and when opening / closing member 8D opens conveying path 10K, sheet S is guided into conveying path 10K.

[0038] At the branch point between conveying paths 10G and 10H, there is provided an opening / closing member 8E that swings about an axis to open one of conveying paths 10G and 10H and close the other. When turning over sheet S, opening / closing member 8E opens conveying path 10G, and conveying rollers 17 convey sheet S counterclockwise until the rear end of sheet S that has entered conveying path 10G passes the branch point, after which opening / closing member 8E opens conveying path 10H, and conveying rollers 17 convey sheet S clockwise.

[0039] At the branch point between conveying path 10J and conveying path 10K, there is provided an opening / closing member 8F that swings about an axis to open one of conveying path 10J and conveying path 10K and close the other. When turning over sheet S, opening / closing member 8F opens conveying path 10J, and conveying rollers 17 convey sheet S counterclockwise until the rear end of sheet S that has entered conveying path 10J passes the branch point, after which opening / closing member 8F opens conveying path 10K, and conveying rollers 17 convey sheet S clockwise.

[0040] At the branch point between conveying path 10L and conveying path 10M, there is provided an opening / closing member 8G that swings about an axis to open one of conveying path 10L and conveying path 10M and close the other. When opening / closing member 8G opens conveying path 10L, sheet S is guided into conveying path 10L, and when opening / closing member 8G opens conveying path 10M, sheet S is guided into conveying path 10M.

[0041] At the branch point between the conveying path 10E and the evacuation path 10Q, an opening / closing member 8H is provided, which swings about an axis to open either the conveying path 10E or the evacuation path 10Q and close the other. When the opening / closing member 8H opens the conveying path 10E, the sheet S is guided into the conveying path 10E, and when the opening / closing member 8H opens the evacuation path 10Q, the sheet S is guided into the evacuation path 10Q.

[0042] The inkjet recording apparatus 1 includes a conveying path 10N connected to the conveying path 10M, and the paper feeder 110 includes a conveying path 10P extending from the conveying path 10N to the sheet alignment device 6 below. The conveying path 10N includes, for example, an electrostatically adsorbed conveying belt 26 that adsorbs and conveys the sheet S using static electricity.

[0043] [Mobile device] 3 and 4 are perspective views showing the moving device 90. The drying device 120 is equipped with a moving device 90 that moves the heater 80 toward and away from the conveying path 10E. The moving device 90 is provided at both the front and rear ends of each heater 80. The moving device 90 includes, for example, a ball screw 91 whose axial direction is the up-down direction and a motor 92. The motor 92 includes a drive pulley 93, the ball screw 91 includes a driven pulley 94, and an endless belt 95 is wound around the drive pulley 93 and the driven pulley 94. The ball screw 91 is fixed to the main body housing 81. The ball screw 91 is rotated by the driving force generated by the motor 92, causing the heater 80 to move toward (see FIG. 3) and away from (see FIG. 4) the conveying path 10E. The moving device 90 is controlled by the control unit 35.

[0044] [sensor] Sensors 30 for detecting the sheet S are provided at each of the conveying paths 10A to 10P and the retreat path 10Q. Of these, a first sensor 31 is provided upstream of the heater 80 in the conveying direction Y of the sheet S, a second sensor 32 is provided downstream of the heater 80 in the conveying direction Y, and a third sensor 33 is provided in the retreat path 10Q. The sensors 30 are used to detect jamming of the sheet S and to control the timing at which the sheet S passes.

[0045] An optical sensor, for example, is used as the sensor 30. The sensor 30 outputs a signal of different levels to the control unit 35 depending on whether the light beam emitted by the sensor 30 is blocked by the sheet S or not. The control unit 35 detects the passage of the sheet S based on the change in the signal level. Furthermore, the control unit 35 determines that a jam of the sheet S has occurred when the time that the sheet S blocks the light beam exceeds a predetermined value.

[0046] [Control Unit] The control unit 35 (see FIG. 2) includes a calculation unit and a storage unit (not shown). The calculation unit is, for example, a CPU (Central Processing Unit). The storage unit includes storage media such as a ROM (Read Only Memory), a RAM (Random Access Memory), and an EEPROM (Electrically Erasable Programmable Read Only Memory). The calculation unit controls each part of the drying device 120 by reading and executing a control program stored in the storage unit. The control unit 35 may be realized by an integrated circuit without using software.

[0047] [Judgment section] The control unit 35 includes a determination unit 36. The determination unit 36 ​​determines whether or not a sheet S exists in a predetermined section based on the detection results from the first sensor 31 and the second sensor 32. The determination unit 36 ​​also calculates the number of sheets S present in the predetermined section based on the number of times the sheet S is detected by the first sensor 31 and the number of times the sheet S is detected by the second sensor 32. A specific calculation method will be described later.

[0048] The basic operation of the image forming system 100 is as follows. When an image formation job is input to the inkjet recording apparatus 1 from the display / operation unit 19, an external computer, or the like, the paper feed roller 5 feeds sheets S one by one from the paper feed cassette 4 to the conveying path 10A. Each time a sheet S is fed, the open / close member 8A alternately opens the conveying paths 10A and 10B, and the lower and upper sheet alignment devices 6 alternately perform sheet alignment processing. When the sheet alignment device 6 feeds the sheet S to the conveying device 7 at a predetermined timing, the conveying device 7 adsorbs the sheet S to the conveying belt 21 and conveys it in the Y direction. When the control unit 2 supplies raster-format image data to the head unit 11 in synchronization with the conveyance of the sheet S, ink is ejected from the head unit 11, and an image is formed on the sheet S. The sheet S with the image formed thereon is conveyed to the drying device 120.

[0049] In the drying device 120, the ink on the sheet S transported along the transport path 10E is dried. In the case of an image forming job for single-sided printing of only one sheet, the sheet S is transported to the post-processing device 130. On the other hand, in the case of an image forming job for single-sided printing of multiple sheets, the sheet S is guided to the transport path 10F, and after being inverted using the transport paths 10G and 10J alternately, it is transported to the post-processing device 130 via the transport path 10L.

[0050] On the other hand, in the case of a double-sided printing image formation job, the sheet S is inverted using the conveying path 10G and the conveying path 10J alternately, and then conveyed to the sheet aligning device 6 below via the conveying paths 10M, 10N, and 10P, where an image is formed on the back side by the inkjet recording device 1. Thereafter, the ink is dried by the drying device 120, and the sheet is conveyed to the post-processing device 130.

[0051] 5 is a flowchart showing a control procedure when an abnormality occurs in the image forming system 100. The control unit 35 executes the following control in parallel with the control of the above basic operations.

[0052] First, in step S01, the control unit 35 determines whether the first sensor 31 has detected the sheet S. If it is determined that the first sensor 31 has detected the sheet S (step S01: YES), the control unit 35 increments the counter by 1 (step S02) and proceeds to step S03. On the other hand, if the first sensor 31 has not detected the sheet S (step S01: NO), the control unit 35 proceeds to step S03.

[0053] In step S03, the control unit 35 determines whether the second sensor 32 has detected the sheet S. If it is determined that the second sensor 32 has detected the sheet S (step S03: YES), the control unit 35 subtracts 1 from the counter (step S04) and proceeds to step S11. On the other hand, if it is determined that the second sensor 32 has not detected the sheet S (step S03: NO), the control unit 35 proceeds to step S11.

[0054] Here, a counter value of 0 indicates that no sheet S is present in the specified section of the conveying path 10E where the heater 80 is provided. On the other hand, a counter value of 1 or more indicates that a sheet S is present in the specified section. Furthermore, when the counter value is 1 or more, the counter value indicates the number of sheets S present in the specified section.

[0055] In step S11, it is determined whether or not an abnormality has occurred in the image forming system 100. Here, an abnormality refers to, for example, when the sensor 30 detects a jam of the sheet S in the conveying paths 10A to 10P. It also includes a case where image formation becomes impossible due to an abnormality in the inkjet recording device 1. If it is determined that no abnormality has occurred in the image forming system 100 (step S11: NO), the control unit 35 repeats the processing from step S01 onwards.

[0056] On the other hand, if it is determined that an abnormality has occurred in the image forming system 100 (step S11: YES), the control unit 35 determines whether the sheet S can be discharged downstream of the predetermined section (step S12). Specifically, if no jamming of the sheet S has occurred in the section of the conveying path 10E downstream of the predetermined section or in the post-processing device 130, the control unit 35 determines that the sheet S can be discharged downstream of the predetermined section (step S12: YES). In this case, the control unit 35 discharges all sheets S from the predetermined section to the post-processing device 130, then stops the conveying device 50 and the heater 80 (step S21), and outputs information indicating an abnormality in the image forming system 100 (step S22). Specifically, the control unit 35 continues to drive the conveying device 50 until the counter value reaches 0, thereby discharging all sheets S from the predetermined section. The information indicating the abnormality may be displayed on the display operation unit 19, output as audio, or transmitted to the computer that sent the image forming job. Two or more of these forms may be used in combination.

[0057] On the other hand, if a jam of sheets S occurs in a section downstream of the predetermined section of the conveying path 10E or in the post-processing device 130, the control unit 35 determines that the sheets S cannot be discharged downstream of the predetermined section (step S12: NO), and determines whether the counter value exceeds the number of sheets that can be evacuated to the evacuation path 10Q (step S13). The number of sheets that can be evacuated to the evacuation path 10Q is preset in the program. If the control unit 35 determines that the counter value does not exceed the number of sheets that can be evacuated to the evacuation path 10Q (step S13: NO), the control unit 35 evacuates all sheets S from the predetermined section to the evacuation path 10Q, then stops the conveying device 50 and the heater 80 (step S23), and outputs information indicating an abnormality in the image forming system 100 (step S22).

[0058] On the other hand, if it is determined that the counter value exceeds the number of sheets S that can be evacuated to the evacuation path 10Q (step S13: YES), the control unit 35 evacuates the number of sheets S that can be evacuated to the evacuation path 10Q (step S14), stops the conveying device 50 and the heater 80, and moves the moving device 90 away from the conveying path 10E (step S15). In this case, one or more sheets S are present in the predetermined section.

[0059] Next, the control unit 35 determines whether the temperature of the heater 80 measured by the sensor 84 has dropped to a predetermined temperature (step S16). If it is determined that the temperature of the heater 80 has not dropped to the predetermined temperature (step S16: NO), the control unit 35 repeats the process of step S16. If it is determined that the temperature of the heater 80 has dropped to the predetermined temperature (step S16: YES), the control unit 35 outputs information indicating an abnormality, the number of sheets S present in the predetermined section, and information prompting the removal of the sheets S (step S17).

[0060] The drying device 120 according to the present embodiment described above includes the conveying device 50 that conveys the sheet S along the conveying path 10E, the heater 80 provided in a predetermined section of the conveying path 10E, a first sensor 31 that is provided upstream of the heater 80 in the conveying direction Y of the sheet S and detects the sheet S, a second sensor 32 that is provided downstream of the heater 80 in the conveying direction Y and detects the sheet S, and a determination unit 36 ​​that determines the presence or absence of the sheet S in the predetermined section based on the detection results of the first sensor 31 and the detection results of the second sensor 32. This configuration makes it possible to determine the presence or absence of the sheet S in the section of the conveying path 10E where the heater 80 is provided.

[0061] Furthermore, the drying device 120 according to this embodiment includes a control unit 35 that controls the drying device 120. When an abnormality occurs in the image forming system 100 including the drying device 120, the control unit 35 controls the conveying device 50 to discharge the sheet S from the predetermined section to the downstream side in the conveying direction Y. This configuration makes it possible to prevent the sheet S from remaining in the section where the heater 80 is provided. Furthermore, the drying device 120 is configured so that the user cannot access the predetermined section until the heater 80 has dropped to a safe temperature. Therefore, in the past, the user had to remove the sheet S from the predetermined section after the temperature of the heater 80 had dropped to a safe temperature. However, in this embodiment, the user is freed from the task of removing the sheet S.

[0062] Furthermore, in the drying device 120 according to this embodiment, the determination unit 36 ​​calculates the number of sheets S present in a predetermined section from the number of times the sheets S are detected by the first sensor 31 and the number of times the sheets S are detected by the second sensor 32, and the control unit 35 drives the conveying device 50 until all the sheets S are discharged from the predetermined section. With this configuration, all of the sheets S present in the section where the heater 80 is provided can be discharged in the minimum driving time.

[0063] Furthermore, in the drying device 120 according to this embodiment, when the sheet S cannot be discharged downstream of the predetermined section in the conveying direction Y, the control unit 35 stops the conveying device 50 and the heater 80, and outputs information prompting the removal of the sheet S after the temperature of the heater 80 has dropped to a predetermined temperature. This configuration can prevent the sheet S from clogging downstream of the section in which the heater 80 is provided in the conveying direction Y. It can also suppress a temperature rise of the sheet S that has accumulated in the section in which the heater 80 is provided. It can also prevent the user from accessing the vicinity of the heater 80 while the heater 80 is still hot.

[0064] Furthermore, the drying device 120 according to this embodiment includes an evacuation path 10Q branching off from the conveying path 10E, and the control unit 35 causes the sheet S to retreat to the evacuation path 10Q when the sheet S cannot be discharged downstream of the predetermined section in the conveying direction Y. This configuration can prevent the sheet S from accumulating in the section where the heater 80 is provided.

[0065] Furthermore, the drying device 120 according to this embodiment includes an evacuation path 10Q branching off from the conveying path 10E, and the control unit 35 stops the conveying device 50 and the heater 80 when the number of sheets S present in a predetermined section exceeds the number that can be evacuated to the evacuation path 10Q, and outputs information urging the removal of the sheets S after the temperature of the heater 80 has dropped to a predetermined temperature. This configuration can prevent the sheets S from clogging the evacuation path 10Q. It can also suppress the temperature rise of the sheets S that are stuck in the section where the heater 80 is provided. It can also prevent the user from accessing the vicinity of the heater 80 while the heater 80 is still hot.

[0066] Furthermore, in the drying device 120 according to this embodiment, the control unit 35 stops the conveying device 50 and the heater 80 after the number of sheets S that can be evacuated to the evacuation path 10Q is evacuated to the evacuation path 10Q, and after the temperature of the heater 80 drops to a predetermined temperature, outputs information urging the removal of the sheets S. With this configuration, the number of sheets S remaining in the section where the heater 80 is provided can be minimized.

[0067] Furthermore, in the drying device 120 according to this embodiment, the control unit 35 outputs information indicating the number of sheets S present in a predetermined section. This configuration reduces the possibility that the user will leave some sheets S unremoved.

[0068] Furthermore, the drying device 120 according to this embodiment includes a moving device 90 that moves the heater 80 toward and away from the conveying path 10E, and the control unit 35 controls the moving device 90 to move the heater 80 away from the conveying path 10E when stopping the heater 80. With this configuration, the sheet S present in the predetermined section can be cooled more quickly than when the heater 80 is not moved away.

[0069] Furthermore, the image forming system 100 according to this embodiment includes the inkjet recording apparatus 1 and the drying apparatus 120 that dries the ink ejected onto the sheet S by the inkjet recording apparatus 1. This configuration can improve the safety of the image forming system 100. [Explanation of symbols]

[0070] 1. Inkjet recording device 10E Transport path 10Q Evacuation route 31 First Sensor 32 Second Sensor 35 Control Unit 36 Judgment section 50 Conveyor 80 Heater 90 Mobile Device 100 Image forming system 120 Drying equipment S seat

Claims

1. a conveying device that conveys a sheet along a conveying path; a heater provided in a predetermined section of the transport path; a first sensor that is provided upstream of the heater in the sheet conveying direction and that detects the sheet; A drying device characterized by comprising: a second sensor located downstream of the heater in the conveying direction and detecting a sheet; and a determination unit that determines the presence or absence of a sheet in the specified section based on the detection results by the first sensor and the detection results by the second sensor.

2. a control unit for controlling the drying device, The drying device according to claim 1, characterized in that the control unit controls the conveying device to discharge the sheet from the specified section to the downstream side in the conveying direction when an abnormality occurs in an image forming system including the drying device.

3. the determining unit calculates the number of sheets present in the predetermined section from the number of times the sheet is detected by the first sensor and the number of times the sheet is detected by the second sensor; The drying device according to claim 2 , wherein the control unit drives the conveying device until all the sheets are discharged from the predetermined section.

4. The drying device described in claim 2 or 3, characterized in that when it is not possible to discharge the sheet downstream of the specified section in the conveying direction, the control unit stops the conveying device and the heater, and after the temperature of the heater drops to a specified temperature, outputs information prompting the removal of the sheet.

5. an evacuation path branched off from the transport path; 4. The drying device according to claim 2, wherein the control unit retracts the sheet into the retraction path when the sheet cannot be discharged downstream of the predetermined section in the transport direction.

6. an evacuation path branched off from the transport path; The drying device according to claim 3, characterized in that the control unit stops the conveying device and the heater when the number of sheets present in the specified section exceeds the number that can be evacuated to the evacuation path, and outputs information prompting the removal of the sheets after the temperature of the heater has dropped to a specified temperature.

7. The drying device according to claim 6, characterized in that the control unit stops the conveying device and the heater after evacuating the number of sheets that can be evacuated to the evacuation path to the evacuation path, and outputs information prompting the removal of the sheets after the temperature of the heater has dropped to the predetermined temperature.

8. The drying device according to claim 3 , wherein the control unit outputs information indicating the number of sheets present in the predetermined section.

9. a moving device that moves the heater toward and away from the transport path; The drying device according to claim 4 , wherein the control unit controls the moving device to move the heater away from the transport path when the heater is stopped.

10. an inkjet recording device; 10. An image forming system comprising: a drying device according to claim 1, which dries ink ejected onto a sheet by the inkjet recording device.

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