Sheet conveying apparatus and image forming system

Abstract

To provide a sheet conveying device and an image forming system capable of easily suppressing floating of a sheet.SOLUTION: The sheet conveying device 8 conveys the sheet Sh1 from the image forming device 10 that forms an ink image on the sheet Sh1 by ejecting ink onto the front side of the sheet Sh1 to the drying device 12 that dries the ink image on the sheet Sh1. The sheet conveyance device 8 includes a suction conveyance unit 81 and an auxiliary suction unit 82. The sucking and conveying unit 81 conveys the sheet Sh1 along the guide surface 800 while sucking the sheet inner wall to the guide surface 800. The auxiliary sucking part 82 is arranged on the downstream side of the D1 part in the conveying direction when viewed from the sucking and conveying part 81 on the guide surface 800, and the sheet Sh1 part to the guide surface 800.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] As a related art, there is known an image forming system (inkjet recording apparatus) that includes an image forming apparatus (image recording unit) that records an image on a sheet (paper) using a surface inkjet method, and a drying device (ink drying processing unit) that performs a drying process on the sheet on which the image has been recorded by the image forming apparatus (see, for example, Patent Document 1). In the image forming system according to the related art, the sheet is delivered to the drying device by a conveying drum of the image forming apparatus. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-40053 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the configuration of the related art described above, the sheet is transferred between the image forming device and the drying device only by the sheet conveyance guide, and therefore, for example, the downstream end of the sheet (the end on the downstream side in the conveyance direction) may be lifted up by wind from a separation mechanism that separates the sheet by blowing air from the image forming device.

[0005] An object of the present invention is to provide a sheet conveying device and an image forming system that can easily prevent a sheet from floating up. [Means for solving the problem]

[0006] A sheet transport device according to one aspect of the present invention transports a sheet from an image forming device that forms an ink image on the sheet by ejecting ink onto the surface of the sheet to a drying device that dries the ink image on the sheet. The sheet transport device includes a suction transport unit and an auxiliary suction unit. The suction transport unit transports the sheet along a guide surface while sucking the sheet against the guide surface. The auxiliary suction unit is located downstream of the suction transport unit in the transport direction on the guide surface, and sucks the sheet against the guide surface.

[0007] An image forming system according to another aspect of the present invention includes the sheet conveying device, the image forming device, and the drying device. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a sheet conveying device and an image forming system that can easily prevent a sheet from floating up. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of an image forming system according to the first embodiment. [Figure 2] FIG. 2 is a block diagram showing the configuration of the image forming apparatus according to the first embodiment. [Figure 3] FIG. 3 is a schematic diagram showing the configuration of the image forming unit of the image forming apparatus according to the first embodiment. [Figure 4] FIG. 4 is a perspective view showing a schematic configuration of a sheet conveying device in the image forming system according to the first embodiment. [Figure 5] FIG. 5 is a cross-sectional view showing a schematic configuration of a sheet conveying device in the image forming system according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following description will discuss preferred embodiments of the present invention with reference to the accompanying drawings. The preferred embodiments are merely examples of the present invention and are not intended to limit the technical scope of the present invention.

[0011] (Embodiment 1) [1] Overall configuration of image forming device First, the overall configuration of an image forming apparatus 10 according to this embodiment will be described with reference to FIGS.

[0012] In this embodiment, as an example, the image forming apparatus 10 is an inkjet recording apparatus (printer) that has a recording head 51 that ejects ink onto the surface of a sheet Sh1 and is capable of performing a print process using an inkjet method in which an image is formed on the sheet Sh1 by the recording head 51. The print process is a process in which an image is formed on an image forming target. The sheet Sh1 is an example of an image forming target (recording medium) on which an image is formed by the image forming apparatus 10, and is a sheet-like medium such as paper or a resin film.

[0013] The image forming apparatus 10 may be a multifunction machine having multiple functions such as a print function, a scanning function for reading image data from a document, a facsimile function, and a copy function, as long as it has the function of forming an image by inkjet printing. The image forming apparatus 10 may also be a facsimile machine or a copy machine.

[0014] As shown in FIG. 1 , the image forming apparatus 10, together with the sheet feeding apparatus 11, the drying apparatus 12, the discharge apparatus 13, and the sheet conveying apparatus 8, constitutes an image forming system 100. In other words, the image forming system 100 according to this embodiment includes the image forming apparatus 10, the sheet feeding apparatus 11, the drying apparatus 12, the discharge apparatus 13, and the sheet conveying apparatus 8. The image forming apparatus 10, the sheet feeding apparatus 11, the drying apparatus 12, the discharge apparatus 13, and the sheet conveying apparatus 8 are connected in this order from upstream to downstream in the conveying direction of the sheet Sh1. This allows the image forming system 100 to continuously perform a series of processes on the sheet Sh1, which are performed by the sheet feeding apparatus 11, the image forming apparatus 10, the drying apparatus 12, and the discharge apparatus 13. The devices in the image forming system 100 are centrally managed by the control apparatus 7 of the image forming apparatus 10. However, the present invention is not limited to this configuration, and a control device that controls and supervises each device may be provided separately from the control device 7.

[0015] The paper feeder 11 can accommodate a plurality of sheets Sh1. The paper feeder 11 supplies the sheets Sh1 one by one to the image forming apparatus 10. The image forming apparatus 10 ejects ink from the recording head 51 onto the sheets Sh1 supplied from the paper feeder 11, forming an image (ink image) by an inkjet method. The image forming apparatus 10 sends the sheets Sh1 on which the images have been formed to a drying device 12 in the downstream stage.

[0016] The image forming apparatus 10 has a first transport unit 4, and forms an image (ink image) on the sheet Sh1 by inkjet printing by ejecting ink from a recording head 51 onto the surface of the sheet Sh1 transported by the first transport unit 4. The first transport unit 4 transports the sheets Sh1 supplied from the paper feeder 11 one by one, and discharges the sheets Sh1 with the image formed on them one by one.

[0017] The sheet conveying device 8 is disposed between the image forming device 10 and the drying device 12. The sheet conveying device 8 conveys the sheet Sh1 from the image forming device 10 to the drying device 12. In other words, the sheet conveying device 8 is located downstream of the image forming device 10 in the conveying direction of the sheet Sh1, receives the sheet Sh1 on which an ink image has been formed and is discharged from the image forming device 10, and passes the sheet Sh1 to the drying device 12 located further downstream.

[0018] The drying device 12 dries the ink image on the sheet Sh1. The drying device 12 has a drying chamber therein, which has a heater or a heat pump type heating unit or the like inside the drying chamber. The drying device 12 dries the ink image formed on the sheet Sh1 by heating the surface of the sheet Sh1 conveyed into the drying chamber from the image forming device 10 via the sheet conveying device 8. The drying device 12 has an exhaust fan that exhausts (discharges) moisture from the drying chamber. The drying device 12 sends the dried sheet Sh1 to the discharge device 13 at the subsequent stage. As a result, the sheet Sh1 on which the image has been formed by the inkjet method in the image forming device 10 is discharged to the discharge device 13.

[0019] The drying device 12 also has a second transport unit 14 (see FIG. 4), and dries the ink image by heating the surface of the sheet Sh1 transported by the second transport unit 14. The second transport unit 14 transports the sheets Sh1 received from the sheet transport device 8 one by one, and discharges the sheets Sh1 after the ink image has dried one by one to the discharge device 13. In other words, the sheet Sh1 is transported from the paper feed device 11 to the discharge device 13 by passing through the first transport unit 4 of the image forming apparatus 10, the sheet transport device 8, and the second transport unit 14 of the drying device 12 in this order.

[0020] The discharge device 13 stocks the sheets Sh1 conveyed from the drying device 12. The discharge device 13 may also have post-processing functions such as a stapler function, a folder function, an inserter function, or a punch function. That is, the discharge device 13 may be a post-processing device that performs post-processing on the sheets Sh1 conveyed from the drying device 12. In this case, the discharge device 13 can perform appropriate post-processing on the sheets Sh1 on which an image has been formed. In single-sided printing, in which an image is formed on only one side of the sheet Sh1, the sheet Sh1 that has been dried in the drying device 12 is sent to the discharge device 13. In double-sided printing, in which images are formed on both sides of the sheet Sh1, the sheet Sh1 is dried in the drying device 12 and then sent to the image forming device 10. Then, an image is formed on the back side of the sheet Sh1 in the image forming device 10, and the sheet Sh1 is dried in the drying device 12 and then sent to the discharge device 13.

[0021] 1 and 2, the image forming apparatus 10 includes, in addition to the first transport unit 4, an image forming section 5, an ink supply section 6, a control device 7, etc. The image forming section 5 has a plurality of recording heads 51. The first transport unit 4, the image forming section 5, the ink supply section 6, the control device 7, etc. are housed in a housing 21 that forms the outer shell of the image forming apparatus 10.

[0022] The first transport unit 4 transports the sheet Sh1 supplied from the paper feed device 11 one by one through the transport path 40. As a result, the sheet Sh1 taken into the housing 21 of the image forming apparatus 10 from the paper feed device 11 is transported through the transport path 40 in the transport direction D1 below the image forming unit 5 and discharged to the drying device 12. The transport path 40 is a path for transporting the sheet Sh1 within the housing 21 and includes a front-stage transport path 401 on the upstream side with respect to the image forming unit 5 and a rear-stage transport path 402 on the downstream side. The first transport unit 4 transports the sheet Sh1 supplied from the paper feed device 11 through the front-stage transport path 401 to the image forming unit 5 and discharges the sheet Sh1 from the image forming unit 5 to the drying device 12 through the rear-stage transport path 402.

[0023] The first transport unit 4 includes a sheet output section 41, one or more pairs of upstream transport rollers 42, a main transport unit 43, and a separation mechanism 44. The sheet output section 41 outputs the sheets Sh1 supplied from the paper feed device 11 one by one to the upstream transport path 401. The multiple pairs of upstream transport rollers 42 take over the transport of the sheets Sh1 from the sheet output section 41 and transport the sheets Sh1 toward the main transport unit 43.

[0024] The main transport unit 43 is disposed below the image forming unit 5. The upstream transport path 401 is a path that runs from the paper feeder 11 to below the image forming unit 5 (above the main transport unit 43). The main transport unit 43 transports the sheet Sh1 while aligning the first side (front side) of the sheet Sh1 with the image forming unit 5. The first side of the sheet Sh1 is the side on which an ink image is formed. The main transport unit 43 has a plurality of tension rollers 431 and a main transport belt 432, and the plurality of tension rollers 431 support and rotate the main transport belt 432. As a result, the main transport unit 43 places the sheet Sh1 on the main transport belt 432 and transports it toward the separation mechanism 44.

[0025] The separation mechanism 44 is located downstream of the main conveyance unit 43 in the conveyance direction, and separates the sheet Sh1 conveyed by the main conveyance unit 43 from the main conveyance belt 432 and sends the sheet Sh1 to the subsequent conveyance path 402. In this embodiment, the separation mechanism 44 is located above the downstream side of the main conveyance belt 432, and separates the sheet Sh1 from the main conveyance belt 432 by blowing air (airflow) onto the main conveyance belt 432. In other words, the sheet Sh1 is separated from the main conveyance belt 432 by the wind blowing against the sheet Sh1 on the main conveyance belt 432.

[0026] The main conveying unit 43 discharges the sheet Sh1 on which the ink image is formed, which has been separated from the main conveying belt 432 by the separation mechanism 44, to the drying device 12 through the subsequent conveying path 402. The subsequent conveying path 402 is a path that leads from below the image forming unit 5 (above the main conveying unit 43) to the drying device 12.

[0027] In addition to or instead of the separation mechanism 44, the first transport unit 4 may have a pair of discharge rollers or the like.

[0028] The image forming unit 5 is located above the main transport unit 43. The image forming unit 5 ejects inks of multiple colors toward the sheet Sh1 transported by the main transport unit 43 of the first transport unit 4, thereby forming an ink image on the first surface of the sheet Sh1.

[0029] The image forming unit 5 includes a plurality of recording heads 51 and a head frame 52 that supports the plurality of recording heads 51. The plurality of recording heads 51 form an image on the sheet Sh1 by ejecting ink of a plurality of colors onto the sheet Sh1 being transported by the main transport unit 43.

[0030] In the example of FIG. 1, the multiple recording heads 51 are divided into four line heads 50 corresponding to inks of black, cyan, magenta, and yellow, respectively. The ink supply unit 6 supplies each color ink (K, C, M, Y) to the recording head 51 of the corresponding line head 50. The four line heads 50 are arranged side by side in the sub-scanning direction D12 and are fixed in a predetermined positional relationship (see FIG. 3). The number of line heads 50 provided in the image forming unit 5 is not limited to four, and may be, for example, two, three, five or more. The sub-scanning direction D12 is the same as the transport direction D1 of the sheet Sh1 on the main transport belt 432.

[0031] The multiple recording heads 51 are arranged at positions where a gap of about 1 millimeter is formed between the ink ejection surface provided on the lower surface of each head and the upper surface of the sheet Sh1 on the main transport belt 432. As shown in FIG. 3, the multiple recording heads 51 are arranged with their respective longitudinal directions aligned with the main scanning direction D11. In the present embodiment, as an example, each line head 50 for each color includes three recording heads 51. The ink ejection surface of each recording head 51 is formed with multiple ink nozzles 53 that eject ink onto the sheet Sh1 transported along the transport path 40. Each recording head 51 has multiple piezoelectric elements corresponding to the multiple ink nozzles 53. When a drive signal is supplied from the control device 7, each piezoelectric element vibrates, thereby pressurizing the ink and causing it to be ejected (squirted) from each ink nozzle 53.

[0032] The control device 7 performs overall control of the image forming apparatus 10. The control device 7 is primarily composed of a computer system having one or more processors and one or more non-volatile memories. In the image forming apparatus 10, the functions of the control device 7 are realized by the one or more processors executing programs. The programs may be pre-recorded in memory (storage unit), provided via a telecommunications line such as the Internet, or provided by being recorded on a non-transitory recording medium readable by a computer system, such as a memory card or optical disk. The one or more processors are composed of one or more electronic circuits including semiconductor integrated circuits. Furthermore, the computer system referred to here includes a microcontroller having one or more processors and one or more memories.

[0033] The control device 7 controls the first transport unit 4, the image forming unit 5, the ink supply unit 6, and the like included in the image forming apparatus 10. In this embodiment, the control device 7 controls not only the image forming apparatus 10 but also the sheet transport device 8 and the like. That is, the control device 7 is electrically connected to each part of the image forming apparatus 10 and the sheet transport device 8, and can, for example, control the image forming unit 5 to form a desired image on the sheet Sh1, or control the sheet transport device 8 to transport the sheet Sh1 from the image forming apparatus 10 to the drying device 12, and the like. In other words, the control device 7 executes an image formation program recorded in memory to implement an image forming method that controls each part of the image forming system 100.

[0034] The image forming apparatus 10 also includes a head cooling device, a maintenance unit, a cap unit, an operation display unit, and the like. The head cooling device cools the recording head 51. The maintenance unit performs a wiping operation to wipe the ink ejection surface (the lower surface of the recording head 51) and clean the ink ejection surface. The cap unit covers the ink ejection surface of the recording head 51 to protect it from drying out. The operation display unit is a user interface in the inkjet recording apparatus. The operation display unit has a display unit such as an LCD display that displays various information in response to control instructions from the control device 7, and an operation unit such as a switch or touch panel that inputs various information to the control device in response to user operations.

[0035] [2] Details of the sheet transport device Next, the sheet conveying device 8 of the image forming system 100 according to this embodiment will be described in more detail with reference to FIGS.

[0036] As described above, the sheet conveying device 8 conveys the sheet Sh1 from the image forming device 10, which forms an ink image on the sheet Sh1 by ejecting ink onto the surface of the sheet Sh1, to the drying device 12, which dries the ink image on the sheet Sh1. In other words, the sheet conveying device 8 is disposed between the image forming device 10 and the drying device 12, and delivers the sheet Sh1, on which the ink image has been formed, from the image forming device 10 to the drying device 12.

[0037] 4, the sheet conveying device 8 receives the sheet Sh1 conveyed by the first conveying unit 4 of the image forming apparatus 10, conveys the sheet Sh1 in the conveying direction D1, and hands it over to the second conveying unit 14 of the drying device 12. In other words, the first conveying unit 4, the sheet conveying device 8, and the second conveying unit 14 are arranged in this order from the upstream side in the conveying direction D1, and work together to convey the sheet Sh1 downstream in the conveying direction D1.

[0038] Meanwhile, as a related art, there is known an image forming system (inkjet recording apparatus) that includes an image forming apparatus (image recording unit) that records an image on a sheet (paper) by a front surface inkjet method, and a drying device (ink drying processing unit) that performs a drying process on the sheet on which the image has been recorded by the image forming apparatus. In the image forming system according to the related art, the sheet is delivered to the drying device by a conveying drum of the image forming apparatus.

[0039] However, in the configuration of the related art described above, the sheet is transferred between the image forming device and the drying device only by the sheet conveyance guide, and therefore, for example, the downstream end of the sheet (the end on the downstream side in the conveyance direction) may be lifted up by wind from a separation mechanism that separates the sheet by blowing air from the image forming device.

[0040] In contrast to this, in this embodiment, the configuration described below makes it possible to realize a sheet conveying device 8 and an image forming system 100 that can easily prevent the sheet Sh1 from floating up.

[0041] That is, the sheet conveying device 8 according to this embodiment includes a suction conveying unit 81 and an auxiliary suction unit 82. The suction conveying unit 81 conveys the sheet Sh1 along the guide surface 800 while sucking the sheet Sh1 onto the guide surface 800. The auxiliary suction unit 82 is disposed downstream of the guide surface 800 in the conveying direction D1 as viewed from the suction conveying unit 81, and sucks the sheet Sh1 onto the guide surface 800.

[0042] In short, the sheet conveying device 8 includes the suction conveying unit 81 that conveys the sheet Sh1 in the conveying direction D1 while sucking the sheet Sh1 onto the guide surface 800, thereby preventing the sheet Sh1 from lifting up (from the guide surface 800) between the image forming device 10 and the drying device 12. Furthermore, the sheet conveying device 8 includes the auxiliary suction unit 82 on the downstream side (the drying device 12 side) of the suction conveying unit 81 in the conveying direction D1, thereby preventing the downstream end of the sheet Sh1 (the downstream end in the conveying direction D1) from lifting up due to, for example, the wind from the separation mechanism 44 acting on the sheet Sh1. This makes it possible to realize a sheet conveying device 8 and an image forming system 100 that can easily prevent the sheet Sh1 from lifting up. As a result, the image forming system 100 can easily maintain stable image quality.

[0043] In particular, the sheet conveying device 8 according to this embodiment further includes an optical sensor 83 for detecting the passage of the sheet Sh1 downstream in the conveying direction D1 (toward the drying device 12) as viewed from the suction conveying section 81. Since it is difficult to arrange the suction conveying section 81, which has a relatively complicated configuration, within the detection range of the optical sensor 83, the sheet Sh1 is likely to lift up within the detection range of the optical sensor 83. However, in this embodiment, the auxiliary suction section 82 can suppress the lifting of the sheet Sh1 in this area.

[0044] Here, the sheet conveying device 8 according to this embodiment is equipped with a plurality of suction conveying units 81F, 81R aligned in the front-to-rear direction (depth direction), which is the main scanning direction D11. Furthermore, the sheet conveying device 8 is also equipped with a plurality of auxiliary suction units 82F, 82R aligned in the front-to-rear direction (depth direction), which is the main scanning direction D11, for the auxiliary suction unit 82. In other words, the sheet conveying device 8 is equipped with a plurality of suction conveying units 81F, 81R and a plurality of auxiliary suction units 82F, 82R.

[0045] Of the multiple suction conveying units 81F, 81R, suction conveying unit 81F is located on the front F side in the front-to-back direction, which is the main scanning direction D11, and suction conveying unit 81R is located on the rear R side in the front-to-back direction, which is the main scanning direction D11. Similarly, of the multiple auxiliary suction units 82F, 82R, auxiliary suction unit 82F is located on the front F side in the front-to-back direction, which is the main scanning direction D11, and auxiliary suction unit 82R is located on the rear R side in the front-to-back direction, which is the main scanning direction D11. Therefore, auxiliary suction unit 82F is located downstream of suction conveying unit 81F in the conveying direction D1, and auxiliary suction unit 82R is located downstream of suction conveying unit 81R in the conveying direction D1.

[0046] Since the multiple suction conveying units 81F, 81R have a common configuration, the following description, unless otherwise specified, will focus on the configuration of one of the suction conveying units 81, 81. Similarly, since the multiple auxiliary suction units 82F, 82R have a common configuration, the following description, unless otherwise specified, will focus on the configuration of one of the auxiliary suction units 82, 82.

[0047] In this embodiment, the suction conveyance unit 81 has a case 80, a suction unit 811, and conveyance rollers 812. The case 80 has a guide surface 800. The suction unit 811 sucks the sheet Sh1 onto the guide surface 800. The conveyance rollers 812 convey the sheet Sh1, which has been sucked onto the guide surface 800, along the guide surface 800.

[0048] More specifically, the upper surface of the case 80 serves as a guide surface 800. The end of the guide surface 800 on the upstream side (the image forming device 10 side) in the conveying direction D1 is an inclined surface that slopes diagonally downward, making it easier to introduce the leading edge of the sheet Sh1 delivered from the image forming device 10 onto the guide surface 800. The case 80 constitutes a suction box in which the internal space is made negative pressure by, for example, a fan or the like.

[0049] The suction section 811 includes an opening formed in the upper surface (guide surface 800) of the case 80. Since the internal space of the case 80 is set to a negative pressure, the suction section 811 sucks in air through the opening, thereby generating a suction force that sucks the sheet Sh1 toward the guide surface 800 (downward).

[0050] One or more (three in this embodiment) transport rollers 812 are provided, and are configured to be exposed to the guide surface 800 from the opening of the suction unit 811 while housed in the case 80. As a result, when the transport rollers 812 rotate, the sheet Sh1 on the guide surface 800 can be transported in the transport direction D1.

[0051] According to this configuration, the suction conveying unit 81 can convey the sheet Sh1 along the guide surface 800 of the case 80 by the conveying rollers 812 while sucking the sheet Sh1 with the suction unit 811. Therefore, when the sheet Sh1 is conveyed by the conveying rollers 812, the sheet Sh1 is less likely to lift up from the guide surface 800.

[0052] The auxiliary suction unit 82 includes a plurality of suction holes 821 formed in the upper surface (guide surface 800) of the case 80. Since the internal space of the case 80 is set to a negative pressure, the auxiliary suction unit 82 sucks air through the plurality of suction holes 821, thereby generating a suction force that sucks the sheet Sh1 toward the guide surface 800 (downward).

[0053] Furthermore, the suction unit 811 is not limited to the above configuration, and may be configured to suck the sheet Sh1 by negative pressure that sucks air through a plurality of small holes formed on the surface of the transport roller 812. Furthermore, the suction unit 811 is not limited to suction by negative pressure, and may be configured to suck the sheet Sh1 by electrostatic force or the like. Similarly, the auxiliary suction unit 82 is not limited to suction by negative pressure, and may be configured to suck the sheet Sh1 by electrostatic force or the like.

[0054] As described above, the sheet conveying device 8 according to this embodiment also includes the optical sensor 83 that detects the sheet Sh1. Here, the guide surface 800 has an extension portion 801 in which the auxiliary suction portion 82 is formed, downstream in the conveying direction D1 as viewed from the suction conveying portion 81. The extension portion 801 has a transmission portion 802 that transmits light from the optical sensor 83.

[0055] In other words, the case 80 has a shape that protrudes toward the downstream side in the conveying direction D1 (toward the drying device 12), and the upper surface of this protruding portion forms the expansion section 801. The expansion section 801 is formed with a plurality of suction holes 821 that communicate with the internal space of the case 80, thereby forming the auxiliary suction section 82. The expansion section 801 is also formed with a transmission section 802 that allows light from the optical sensor 83 to pass through.

[0056] 4, the optical sensor 83 is disposed downstream in the conveying direction D1 as viewed from the suction conveying unit 81 and above the center in the main scanning direction D11. The optical sensor 83 is a reflective sensor, and a mirror is disposed below the optical sensor 83 at a position facing the optical sensor 83. When there is no obstruction (sheet Sh1), the optical sensor 83 receives light from below that is emitted downward and reflected by the mirror. Therefore, it is possible to determine that the sheet Sh1, which is an obstruction, is passing below the optical sensor 83 at a timing when the optical sensor 83 does not receive light from below.

[0057] The transparent portion 802 is formed in the center in the main scanning direction D11 of a portion of the case 80 that protrudes downstream in the conveying direction D1, and has a notched shape that is recessed upstream in the conveying direction D1. In other words, because the transparent portion 802 is located between the optical sensor 83 and the mirror, it is possible to prevent the light from the optical sensor 83 from being blocked by the case 80. The extended portion 801 is divided into two in the main scanning direction D11, with the transparent portion 802 in between.

[0058] With this configuration, even if the extension part 801 is located in a position that interferes with the optical sensor 83, it is possible to prevent the light from the optical sensor 83 from being blocked and to detect the passage of the sheet Sh1. Therefore, compared to when the extension part 801 is not present, the degree of freedom in arranging the optical sensor 83 is increased.

[0059] Furthermore, in the sheet conveying device 8 according to this embodiment, as described above, the guide surface 800 is provided with a plurality of auxiliary suction units 82. The suction forces of the plurality of auxiliary suction units 82F, 82R are individually adjustable. That is, the suction forces of the auxiliary suction unit 82F located on the front F side in the front-rear direction, which is the main scanning direction D11, and the auxiliary suction unit 82R located on the rear R side in the front-rear direction, which is the main scanning direction D11, are individually adjustable. The suction forces are adjusted, for example, by a shutter provided for each of the auxiliary suction units 82F, 82R, which adjusts the apertures of the plurality of suction holes 821. That is, for example, by using a shutter to narrow (reduce) the apertures of the plurality of suction holes 821 only for the auxiliary suction unit 82R, the suction force of the auxiliary suction unit 82R can be reduced.

[0060] According to this configuration, the auxiliary suction units 82F, 82R can individually adjust the suction force depending on the passing position of the sheet Sh1 in the main scanning direction D11, thereby suppressing the lifting of the sheet Sh1 with an appropriate suction force. As an example, when the sheet Sh1 is biased toward the rear R in the front-to-rear direction, which is the main scanning direction D11, the suction force of the auxiliary suction unit 82F can be made relatively smaller than that of the auxiliary suction unit 82R to prevent the application of an unnecessarily large suction force.

[0061] [3] Variation The multiple components included in the image forming apparatus 10 may be distributed across multiple housings. For example, the image forming unit 5 and the ink supply unit 6 may be provided in separate housings.

[0062] Conversely, in the first embodiment, at least one of the components provided separately from the image forming apparatus 10 may be provided in the image forming apparatus 10 as a component of the image forming apparatus 10. For example, at least one of the paper feeder 11, the dryer 12, and the discharger 13 may be provided in the housing 21, or may be configured integrally with the image forming apparatus 10.

[0063] Furthermore, the image forming object on which an image is formed by the image forming apparatus 10 is not limited to a sheet Sh1 such as paper or a resin film, but may also be, for example, a roll of fabric such as a nonwoven fabric or cloth. In this case, the image forming apparatus 10 is a textile printing machine (textile printer) that records an image on the fabric by ejecting ink onto the fabric and dyeing the fibers of the fabric with the ink.

[0064] Furthermore, the "recording element" is not limited to the ink nozzle 53, but may be, for example, the recording head 51 or the line head 50. Furthermore, if the image forming apparatus 10 is of a type other than an inkjet type, the recording element is changed as appropriate depending on the type of the image forming apparatus 10, etc.

[0065] Furthermore, the optical sensor 83 is not limited to a reflective sensor, but may be, for example, a transmissive sensor in which a light-emitting portion and a light-receiving portion are arranged opposite each other.

[0066] Furthermore, it is not essential that the suction power of the plurality of auxiliary suction units 82F, 82R be adjustable individually, and the suction power of the plurality of auxiliary suction units 82F, 82R may be adjusted collectively.

[0067] Furthermore, it is not essential that the sheet conveying device 8 includes multiple suction conveying units 81, and only one suction conveying unit 81 may be provided. Similarly, it is not essential that the sheet conveying device 8 includes multiple auxiliary suction units 82, and only one auxiliary suction unit 82 may be provided.

[0068] [Appendix to the invention] The following will provide an outline of the invention extracted from the above-described embodiment. Note that the configurations and processing functions described in the following supplementary notes can be selected and combined as desired.

[0069] <Appendix 1> 1. A sheet conveying device that conveys a sheet from an image forming device that forms an ink image on a sheet by ejecting ink onto a surface of the sheet to a drying device that dries the ink image on the sheet, a suction conveyance unit that conveys the sheet along a guide surface while sucking the sheet against the guide surface; an auxiliary suction unit that is disposed on the guide surface downstream in the conveying direction as viewed from the suction conveying unit and that sucks the sheet onto the guide surface; Sheet transport device.

[0070] <Appendix 2> The suction conveying unit is a case having the guide surface; a suction section that sucks the sheet onto the guide surface; a conveying roller that conveys the sheet sucked onto the guide surface along the guide surface, 2. The sheet conveying device according to claim 1.

[0071] <Appendix 3> Further, an optical sensor for detecting the sheet is provided, the guide surface has an expansion portion where the auxiliary suction portion is formed, on the downstream side in the conveying direction as seen from the suction conveying portion, The extension portion has a transparent portion that transmits light of the optical sensor. 3. The sheet conveying device according to claim 1 or 2.

[0072] <Appendix 4> The guide surface is provided with a plurality of auxiliary suction portions, The suction power of each of the plurality of auxiliary suction units can be individually adjusted. 4. The sheet conveying device according to any one of claims 1 to 3.

[0073] <Appendix 5> A sheet conveying device according to any one of Supplementary Notes 1 to 4; the image forming apparatus; The drying device, Imaging system. [Explanation of symbols]

[0074] 8. Sheet transport device 10 Image forming device 12 Drying equipment 80 cases 81 Suction and transport unit 82,82F,82R Auxiliary suction section 83 Optical Sensor 100 Image forming system 800 guide surface 801 Extension 802 Transparent part 811 Suction part 812 Transport roller D1 Conveying direction Sh1 sheet

Claims

1. 1. A sheet conveying device that conveys a sheet from an image forming device that forms an ink image on a sheet by ejecting ink onto a surface of the sheet to a drying device that dries the ink image on the sheet, a suction conveyance unit that conveys the sheet along a guide surface while sucking the sheet against the guide surface; an auxiliary suction unit that is disposed on the guide surface downstream in the conveying direction as viewed from the suction conveying unit and that sucks the sheet onto the guide surface; Sheet transport device.

2. The suction conveying unit is a case having the guide surface; a suction section that sucks the sheet onto the guide surface; a conveying roller that conveys the sheet sucked onto the guide surface along the guide surface, The sheet transport device according to claim 1 .

3. Further, an optical sensor for detecting the sheet is provided, the guide surface has an expansion portion where the auxiliary suction portion is formed, on the downstream side in the conveying direction as seen from the suction conveying portion, The extension portion has a transparent portion that transmits light of the optical sensor.

3. The sheet conveying device according to claim 1 or 2.

4. The guide surface is provided with a plurality of auxiliary suction portions, The suction power of each of the plurality of auxiliary suction units can be individually adjusted.

3. The sheet conveying device according to claim 1 or 2.

5. The sheet conveying device according to claim 1 or 2; the image forming apparatus; The drying device, Imaging system.

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