Sheet conveying device and image forming apparatus

Abstract

To improve workability during maintenance.SOLUTION: A sheet conveying device according to the present invention comprises: an upper door unit 43 capable of storing an upper belt unit 410; and a first displacement portion 441 that displaces the upper belt unit 410 relative to the upper door unit 43 between a storage position stored in the upper door unit 43 and a maintenance position protruding from the upper door unit 43. The upper door unit 43 and the upper belt unit 410 are displaced into: a first state in which the upper door unit 43 is positioned in a closed position and the upper belt unit 410 is positioned in the storage position and a sheet is conveyed by the upper belt; a second state in which the upper door unit 43 is positioned in an open position and the upper belt unit 410 is positioned in the storage position and a sheet conveyance path is opened; and a third state in which the upper door unit 43 is positioned in the open position and the upper belt unit 410 is positioned in the maintenance position and the attachment / detachment of the upper belt to / from the upper belt unit 410 is permitted.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a sheet transport device that transports a sheet, and an image forming apparatus including the same. [Background technology]

[0002] Patent Document 1 describes a configuration in which a sheet is sandwiched and conveyed by a pair of belts, and the sheet is heated by a heater. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-15290 A Summary of the Invention [Problem to be solved by the invention]

[0004] Here, the fixing function section is required to be configured so that the sheet can be removed from the front of the device in order to improve the ease of sheet removal when a jam occurs. For example, when the sheet transport path is arranged substantially horizontally and other devices are connected to the left and right, it is desirable to configure the upper belt unit and lower belt unit of the fixing function section so that they can be separated. In this case, for example, when replacing the belt of the upper belt unit, it is necessary to remove the exterior cover and inner cover and access from above the upper door, or to remove the upper door itself from the device body to perform the work.

[0005] However, as described above, the task of replacing the belt of the belt unit is difficult because disassembly work to access the belt is complicated, or work at height and with heavy objects is required.

[0006] SUMMARY OF THE DISCLOSURE An object of the present invention is to provide a sheet conveying device and an image forming apparatus that can improve the efficiency of maintenance work, such as belt replacement. [Means for solving the problem]

[0007] The sheet transport device of the present invention is a sheet transport device that transports a sheet, and includes a housing, a belt unit having a detachable transport belt that transports a sheet, a storage section that can store the belt unit and is displaceable between a closed position and an open position by rotating with respect to the housing, a displacement section that displaces the belt unit relative to the storage section to a first position stored in the storage section and a second position protruding from the storage section, and a displacement section that is disposed opposite the belt unit when the storage section is located at the closed position and the belt unit is located at the first position, and displaces the belt unit together with the transport belt. and a rotating body that clamps and transports a sheet, and the storage section and the belt unit are capable of being displaced between a first state in which the storage section is located at the closed position and the belt unit is located at the first position, and the sheet is transported by the transport belt, a second state in which the storage section is located at the open position and the belt unit is located at the first position, and the transport path for the sheet is open, and a third state in which the storage section is located at the open position and the belt unit is located at the second position, and the transport belt is allowed to be attached to and detached from the belt unit.

[0008] The image forming apparatus of the present invention comprises an image forming unit that ejects ink onto a sheet to form an image, and a sheet conveying device that conveys the sheet on which the image has been formed, and is characterized in that the sheet conveying device is the sheet conveying device described above. Effect of the Invention

[0009] According to the present invention, it is possible to improve the workability during maintenance such as belt replacement. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional view showing the configuration of an image forming system according to an embodiment. [Diagram 2] FIG. 2 is a schematic cross-sectional view showing the configuration of a fixing module according to the embodiment. [Diagram 3]1 is a perspective view showing a first state in which an upper door unit of the fixing module according to the embodiment is located at a closed position. FIG. [Figure 4] 11 is a perspective view showing a second state in which the upper door unit of the fixing module according to the embodiment is located in the open position and the upper belt unit is located in the upper storage position. FIG. [Diagram 5] 11 is a perspective view showing the gas spring when the upper door unit of the fixing module according to the embodiment is located in a closed position. FIG. [Figure 6] 11 is a perspective view showing a third state in which the upper door unit of the fixing module according to the embodiment is located in the open position and the upper belt unit is located in the maintenance position. FIG. [Figure 7] 5A and 5B are diagrams showing a locking mechanism of the fixing module according to the embodiment, in which FIG. 5A is a perspective view and FIG. [Figure 8] 11 is a cross-sectional side view showing a third state of the fixing module according to the embodiment; FIG. [Figure 9] 13 is a perspective view illustrating a state in which the lower belt unit is located at a pulled-out position when the fixing module according to the embodiment is in a third state. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present embodiment will be described with reference to the drawings. First, a schematic configuration of an image forming system according to the present embodiment will be described with reference to FIG.

[0012] [Image formation system] The inkjet recording system 100 of this embodiment uses an inkjet recording method in which ink is ejected to form an image on a sheet, and is a so-called sheet-fed inkjet recording device that forms an ink image on a sheet using two liquids, namely, a reaction liquid and ink. The sheet may be any recording material that can receive ink, such as paper such as plain paper or thick paper, plastic film such as an overhead projector sheet, specially shaped sheets such as envelopes or index paper, and cloth.

[0013] 1, an inkjet recording system 100 of this embodiment is an example of an image forming apparatus, and includes a feeding module 1000, a print module 2000, and a drying module 3000. The inkjet recording system 100 further includes a fixing module 4000, a cooling module 5000, an inverting module 6000, and a stacking module 7000. A sheet S supplied from the feeding module 1000 is subjected to various processes while being transported along a transport path in each module, and is finally discharged to the stacking module 7000.

[0014] Each of the modules from the feeding module 1000 to the stacking module 7000 may have a separate housing, and these housings may be connected to configure the inkjet recording system 100. Alternatively, the feeding module 1000, the print module 2000, the drying module 3000, the fixing module 4000, the cooling module 5000, the reversing module 6000, and the stacking module 7000 may be arranged in a single housing.

[0015] The feeding module 1000 has storage chambers 1500a, 1500b, and 1500c for storing sheets S, and the storage chambers 1500a to 1500c are provided so as to be able to be pulled out to the front side of the apparatus in order to store the sheets S. The sheets S are fed one by one in each of the storage chambers 1500a to 1500c by a separation belt and a transport roller, and are transported to the print module 2000. The number of storage chambers 1500a to 1500c is not limited to three, and one, two, or four or more may be provided.

[0016] The print module 2000, which is an example of an image forming unit, has a pre-imaging registration correction unit (not shown), a print belt unit 2010, and a recording unit 2020, and forms an image by ejecting ink onto a sheet S. The sheet S conveyed from the feeding module 1000 has its inclination and position corrected by the pre-imaging registration correction unit, and is conveyed to the print belt unit 2010. The recording unit 2020 is disposed at a position facing the print belt unit 2010 with respect to the conveying path. The recording unit 2020 is an inkjet recording unit that forms an image by ejecting ink onto the conveyed sheet S from above using a recording head. A plurality of recording heads that eject ink are arranged along the conveying direction. In this embodiment, in addition to the four colors of Y (yellow), M (magenta), C (cyan), and Bk (black), a total of five line-type recording heads corresponding to the reaction liquid are provided. The sheet S is adsorbed and conveyed by the print belt unit 2010, so that a clearance between the sheet S and the recording head is ensured.

[0017] The number of ink colors and recording heads are not limited to the above five. The inkjet method may be a method using a heating element, a method using a piezoelectric element, a method using an electrostatic element, a method using a MEMS (Micro Electro Mechanical Systems) element, or the like. Each color of ink is supplied to the recording head from an ink tank (not shown) via an ink tube. The ink contains a resin component of "0.1% by mass to 20.0% by mass" based on the total mass of the ink, water, a water-soluble organic solvent, a coloring material, wax, additives, and the like.

[0018] When the sheet S on which an image is formed by the recording unit 2020 is transported by the print belt unit 2010, it is detected by an in-line scanner (not shown) arranged downstream of the recording unit 2020 in the transport direction of the sheet S. Here, the misalignment and color density of the image formed on the sheet S are detected, and the image formed on the sheet S, its density, etc. are corrected based on the misalignment and color density of the image.

[0019] The drying module 3000 is an example of a drying device, and dries the sheet S on which an image is formed by ejecting ink by blowing hot air onto the sheet S. As shown in FIG. 2, the drying module 3000 has a decoupling section 40, a drying belt unit 5, and a hot air blowing unit 8. The drying module 3000 reduces the liquid content of the ink and reaction liquid applied to the sheet S in order to improve the fixation of the ink to the sheet S by the subsequent fixing module 4000. The sheet S on which the image is formed is transported to the decoupling section 40 arranged in the drying module 3000. In the decoupling section 40, a frictional force is generated between the sheet S and the belt by the wind pressure of the wind blown from above, and the sheet S is transported by the belt. In this way, the sheet S placed on the belt is transported by the frictional force, thereby preventing the sheet S from shifting when the sheet S is transported between the print belt unit 2010 and the decoupling section 40. The sheet S transported from the decoupling section 40 is adsorbed and transported by the drying belt unit 5, and the ink and reaction liquid applied to the sheet S are dried by blowing hot air onto the sheet S from the hot air blowing unit 8 arranged above the belt.

[0020] In this way, the ink and reaction liquid applied to the sheet S are heated by the drying module 3000 to promote evaporation of the moisture, thereby preventing so-called cockling, in which ink splatters on the sheet S and leaves a border-like line around the periphery. As a heater for heating the air, for example, an electric heating wire or an infrared heater is preferable from the standpoint of safety and energy efficiency. In addition, the drying method may be configured by combining a method of applying hot air, a method of irradiating the surface of the sheet S with electromagnetic waves (ultraviolet rays, infrared rays, etc.), and a conductive heat transfer method by contact with a heating element.

[0021] 1, the fixing module 4000 has a fixing belt unit 4100. The fixing belt unit 4100 fixes ink onto the sheet S by passing the sheet S, on which an image has been formed and which has been conveyed from the drying module 3000, between a heated upper belt unit and a lower belt unit. The fixing belt unit 4100 will be described in detail later.

[0022] The cooling module 5000 has a plurality of cooling sections 5001, which cool the high-temperature sheet S transported from the fixing module 4000. The cooling section 5001, for example, takes in outside air into a cooling box with a fan to increase the pressure inside the cooling box, and cools the sheet S by blowing air from the cooling box through a nozzle due to the pressure against the sheet S. The cooling sections 5001 are disposed on both sides of the transport path of the sheet S, and cool both sides of the sheet S.

[0023] The cooling module 5000 is provided with a transport path switching unit 5002. The transport path switching unit 5002 switches the transport path of the sheet S depending on whether the sheet S is transported to the reversing module 6000 or to a double-sided transport path for double-sided printing in which images are formed on both sides of the sheet S.

[0024] The inversion module 6000 has an inversion section 6400. The inversion section 6400 inverts the sheet S being conveyed, and changes the orientation of the sheet S when it is discharged to the stacking module 7000. The stacking module 7000 has a top tray 7200 and a stacking section 7500, and stacks the sheet S conveyed from the inversion module 6000.

[0025] During double-sided printing, the sheet S is transported to a transport path below the cooling module 5000 by the transport path switching unit 5002. Thereafter, the sheet S passes through a double-sided transport path including the fixing module 4000, the drying module 3000, the print module 2000, and the feeding module 1000, and is returned to the print module 2000. The double-sided transport section of the fixing module 4000 is provided with an inversion unit 4200 that inverts the sheet S. The sheet S returned to the print module 2000 has an image formed with ink on the other side on which the image is not formed, and is then discharged from the drying module 3000 through the inversion module 6000 to the stacking module 7000.

[0026] [Fixing module] Next, the fixing module 4000 will be described in detail with reference to FIGS. 2 to 9. In this embodiment, the fixing module 4000 is an example of a sheet conveying device that conveys a sheet. FIG. 2 is a schematic diagram showing the fixing module 4000. A fixing belt unit 4100 is provided on the upper part of the fixing module 4000. The fixing belt unit 4100 has a substantially linear sheet conveying path 1 for receiving the sheet S discharged from the drying module 3000, performing fixing, and then delivering the sheet S to the cooling module 5000. In addition, in each drawing, the front side of the inkjet recording system 100 is represented as the front direction F, the rear side is represented as the rear direction B, the right side is represented as the right direction R, the left side is represented as the left direction L, the upper side is represented as the upper direction U, and the lower side is represented as the lower direction D. In addition, an operation unit (not shown) operated by an operator is provided on the front side of the inkjet recording system 100.

[0027] The fixing belt unit 4100 includes an upper belt unit 410 and a lower belt unit 420. The upper belt unit 410 is disposed vertically above the lower belt unit 420. The upper belt unit 410 includes an upper belt 411, which is an example of a fixing belt and a conveyor belt (first conveyor belt), and a tension roller 412 that applies tension to the upper belt 411. That is, the upper belt unit 410 is an example of a belt unit (first belt unit), and includes the upper belt 411 that conveys the sheet S in a detachable manner. The lower belt unit 420 is an example of a second belt unit, and includes a lower belt 421, a tension roller 422 that applies tension to the lower belt 421, and a pad 423 having an arc-shaped curved surface. The pad 423 is disposed so as to form a nip with the upper belt 411 via the lower belt 421.

[0028] The sheet S is conveyed while being sandwiched in the nip between the upper belt unit 410 and the lower belt unit 420. That is, the lower belt 421 is an example of a rotating body and a second conveyor belt, and is disposed opposite the upper belt unit 410 when the upper door unit 43 is located in the closed position and the upper belt unit 410 is located in the upper storage position (see FIG. 2). At this time, the sheet S is sandwiched together with the upper belt 411 and conveyed. The pressure of the nip is determined by the tension and thickness of the upper belt 411 and the curvature of the pad 423. If the pressure of the nip is too high, the ink of the sheet S may adhere to the upper belt unit 410 and the ink may peel off from the sheet S. Therefore, the pressure is preferably 1 Pa to 2000 Pa, and more preferably 1 Pa to 200 Pa.

[0029] When the curvature of the pad 423 becomes large, the difference in the conveying path between the front and back of the sheet S becomes large, and there is a possibility that friction will occur between the sheet S and the belt. When the curvature of the pad 423 becomes large, there is a possibility that a phenomenon will occur in which the sheet S itself memorizes the curved shape and curls, so it is desirable that the curvature radius of the pad 423 is 50 mm or more. Also, from the viewpoint of manufacturing precision, it is desirable that the curvature radius of the pad 423 is 100,000 mm or less. Due to these constraints, in this embodiment, the tension of the upper belt 411 is 200 N, the thickness is 0.3 mm, the curvature of the pad 423 is 30,000 mm, and the nip pressure is about 16 Pa.

[0030] By adopting such a configuration, uniform pressure can be applied even in a wide nip. As a result, even when the temperature of the upper belt unit 410 is set to the melting point of wax or the boiling point of water, the contact time between the sheet S and the upper belt unit 410 can be increased to sufficiently transfer heat to the sheet S. However, if the nip continues to be formed after the heat is sufficiently transferred, a phenomenon occurs in which ink adheres to the upper belt 411 and peels off the sheet S, or the upper belt 411 and the sheet S rub against each other, causing a disturbance in the image, so a contact time that is too long is not preferable. Therefore, it is desirable that the time required for the leading edge of the sheet S to enter the entrance of the nip and exit the exit of the nip is 0.5 s to 4 s. In this embodiment, a pad 423 with a length of 900 mm in the sheet transport direction is used, the sheet S is transported at 700 mm / s, and the time required for the leading edge of the sheet S to exit the exit of the nip from the entrance of the nip is about 1.3 s. Since moisture is necessary for ink to penetrate into the sheet S, it is preferable that the upper belt 411 and the lower belt 421 are impermeable to prevent moisture evaporated from the surface of the sheet S from escaping through the upper belt 411 or the lower belt 421 that they come into contact with when the sheet becomes hot.

[0031] Thus, in this embodiment, the fixing module 4000 is an example of a fixing device, and has a heater 413 in the upper belt unit 410, and heats and pressurizes the sheet S on which an image is formed between the upper belt 411 and the lower belt 421 to fix the image to the sheet S.

[0032] [Jam Clearance] If a sheet becomes jammed or slips in the sheet transport path 1, causing the specified transport timing to deviate, the device detects the jam. In this case, the sheet S remaining in the sheet transport path 1 is automatically discharged to the purge tray, but if the remaining sheet cannot be discharged to the purge tray, the user must remove the remaining sheet. The sheet S is conveyed while being sandwiched in the nip between the upper belt unit 410 and the lower belt unit 420, but if the sheet S remains in the nip when a jam occurs, the user must open the nip and remove the remaining sheet.

[0033] As shown in FIGS. 3 to 5, the fixing module 4000 has an upper door unit 43 that can be opened in the upward direction U. The upper belt unit 410 of the fixing belt unit 4100 is disposed inside the upper door unit 43, and the upper door unit 43 is configured to be able to be opened in the upward direction U together with the upper belt unit 410. The upper door unit 43 is rotatably connected to the device body 400 by a support shaft 44 (see FIG. 5) provided on the rear direction B side of the device body 400, which is an example of a housing. The support shaft 44 is an example of a first rotation shaft, and is provided on the rear side of the device body 400 with respect to the sheet width direction (front-rear direction) that intersects with the sheet conveying direction, and is provided along the sheet conveying direction. The upper door unit 43 is provided rotatably with respect to the device body 400 around the support shaft 44.

[0034] The upper door unit 43 has a handle 431 on the front direction F side of the device body 400, and is rotated and opened by pulling up the handle 431 in the upward direction U. The upper door unit 43 is an example of a storage section, and is provided separately from the upper belt unit 410, can store the upper belt unit 410, and can be displaced to a closed position (see FIG. 3) and an open position (see FIGS. 4 and 6) by rotating with respect to the device body 400. In this embodiment, the upper door unit 43 is composed of a top plate and side plates, and functions as an upper cover for the device body 400. The upper door unit 43 is not limited to having only the function of a cover, and may be integrated with, for example, a display unit, an operation unit, etc.

[0035] When a jam occurs, the user can open the upper door unit 43 upward by pulling up the handle 431 of the upper door unit 43, and remove the sheet S remaining inside the apparatus main body 400 from the front of the apparatus. In this embodiment, a gas spring 45 is provided to improve operability when the user opens and closes the upper door unit 43. The gas spring 45 is an example of a second biasing portion, and biases the upper door unit 43 toward the open position.

[0036] In this embodiment, the upper door unit 43 is provided so as to be rotatable between a horizontal closed position and an open position inclined 30 degrees from the horizontal. When the opening angle of the upper door unit 43 is a first angle or less with respect to the horizontal direction, the gas spring 45 has a biasing force to rotate the upper door unit 43 and the upper belt unit 410 to the closed position by their own weight. The first angle here is, for example, 5 degrees. Also, when the opening angle of the upper door unit 43 is a second angle or more with respect to the horizontal direction, the gas spring 45 has a biasing force to rotate the upper door unit 43 to the open position. The second angle here is, for example, 20 degrees. Thus, by providing the gas spring 45, the upper door unit 43 can be automatically closed when the opening angle is 5 degrees or less, and automatically opened when the opening angle is 20 degrees or more, improving operability.

[0037] [Upper belt unit part replacement work] The upper belt unit 410 of the fixing belt unit 4100 is provided with components such as an upper belt 411, multiple tension rollers 412, a roller drive unit (not shown), a heater 413 which is an example of a heating unit, and a sensor (not shown). These components have a risk of failure during their product life, and are required to be replaceable in the market in order to accommodate periodic replacement and replacement due to accidental failure. In the commercial printing market, product operation rate is of utmost importance to users, so it is desirable for replacement work to be performed quickly and reliably.

[0038] Therefore, in this embodiment, a configuration is adopted that enables parts replacement of the upper belt unit 410 with the upper door unit 43 open upward, and will be described with reference to Figs. 6 to 8. When performing work such as part replacement, cleaning, or oiling, a handle 431 arranged on the front direction F side of the upper door unit 43 is pulled up in the upward direction U, and the upper door unit 43 is rotated upward to open the sheet transport path 1. The upper door unit 43 is held in an open position by a holding member (not shown) (see Fig. 4).

[0039] As shown in Fig. 8, the fixing module 4000 has a first displacement portion 441 as a displacement portion. The first displacement portion 441 is provided to displace the upper belt unit 410 relative to the upper door unit 43 between an upper storage position (see Fig. 4) stored in the upper door unit 43 and a maintenance position (see Figs. 6 and 8) protruding from the upper door unit 43. The upper storage position here is an example of the first position, and the maintenance position is an example of the second position. The first displacement portion 441 has a rotation shaft 46 which is an example of a second rotation shaft, a stopper 51 which is an example of a holding portion, and a gas spring 47 which is an example of a first biasing portion.

[0040] The rotating shaft 46 is provided on the rear side of the upper door unit 43 when the upper door unit 43 is located at the closed position in the sheet width direction (front-rear direction), and is arranged along the sheet conveying direction. The upper belt unit 410 is provided rotatably about the rotating shaft 46. The upper belt unit 410 arranged inside the upper door unit 43 is supported rotatably relative to the upper door unit 43 by the rotating shaft 46 provided on the rear direction B side of the upper door unit 43. The upper belt unit 410 is fixed to the upper door unit 43 by a lock mechanism 50 (see FIG. 7) arranged on the front side of the upper door unit 43.

[0041] The configuration of the lock mechanism 50 will be described. The lock mechanism 50 has a lock lever 28, a rotating shaft 29, a lock member 30, and a lock hole 31. The lock lever 28 is provided so as to be rotatable within a predetermined angle around the rotating shaft 29, and the lock member 30 is fixed to the rotating shaft 29. With the rotation of the lock lever 28, the rotating shaft 29 can rotate the lock member 30 from the locked position to the unlocked position. A lock hole 31 into which the rotating shaft 29 is inserted is formed on the upper door unit 43 side. The lock hole 31 is shaped so that the lock member 30 positioned at the unlocked angle can pass through it, and the lock can be released at this position.

[0042] When the lock lever 28 of the lock mechanism 50 is turned to release the lock while the upper door unit 43 is open in the upward direction U, the upper belt unit 410 rotates about the rotation shaft 46, and the front side rotates downward due to the weight of the upper belt unit 410. In this way, the lock mechanism 50 switches between a locked state in which the upper belt unit 410 is fixed to the upper storage position relative to the upper door unit 43, and a released state in which the locked state is released and the upper belt unit 410 is allowed to rotate from the upper storage position to the maintenance position.

[0043] The upper belt unit 410 hits a stopper 51 provided on the upper door unit 43 and stops rotating at the maintenance position. That is, the stopper 51 holds the upper belt unit 410 at the maintenance position when the upper door unit 43 is located at the open position. The upper belt 411 can be drawn out to the front side of the device main body 400 in the sheet width direction when the upper door unit 43 is located at the open position and the upper belt unit 410 is located at the maintenance position. In this state, an operator can replace or perform maintenance on the upper belt 411.

[0044] The upper belt unit 410 located at the maintenance position is preferably in a substantially horizontal position, but may be slightly inclined. However, if the upper belt unit 410 is inclined, for example, to the upward direction U side by more than 10 degrees from the horizontal, part replacement will be performed at a high place, which will result in poor workability. On the other hand, if the upper belt unit 410 is inclined, for example, to the downward direction D side by more than 10 degrees from the horizontal, it will be necessary to be careful not to drop the removed parts such as the upper belt 411 to the front side during part replacement, which will result in poor workability. Therefore, it is preferable that the angle at which the front side of the upper belt unit 410 is inclined to the horizontal plane is within ±10 degrees.

[0045] 8, a gas spring 47 is provided between the upper door unit 43 and the upper belt unit 410. The gas spring 47 is an example of a first biasing member, and biases the upper belt unit 410 toward the upper storage position with respect to the upper door unit 43 that is located in the open position. In particular, when the upper belt unit 410 is heavy, providing the gas spring 47 can improve operability.

[0046] In this embodiment, the gas spring 47 is disposed on the upper part of the upper belt unit 410 and is fastened to a fixed member 48 in the upper door unit 43 and a fixed member 49 in the upper belt unit 410, and assists the opening and closing operation of the upper belt unit 410. In this embodiment, the gas spring 47 is disposed on the upper part of the upper belt unit 410, so that it does not get in the way of the replacement work when replacing parts with the upper belt unit 410 open. In addition, the biasing force of the gas spring 47 is set so that the upper belt unit 410 does not lift up by itself due to the weight change when the parts are removed. In addition, the upper door unit 43 is held (locked) by a holding member (not shown) so that it does not close with the upper belt unit 410 in the open position.

[0047] The above-mentioned upper door unit 43 and upper belt unit 410 can be displaced to the following first state, second state, and third state. The first state is a state in which the upper door unit 43 is located at the closed position, and the upper belt unit 410 is located at the upper storage position, and the sheet S is transported by the upper belt 411 (see FIG. 3). The second state is a state in which the upper door unit 43 is located at the open position, and the upper belt unit 410 is located at the upper storage position, and the transport path of the sheet S is open (see FIG. 4). The third state is a state in which the upper door unit 43 is located at the open position, and the upper belt unit 410 is located at the maintenance position, and the upper belt 411 is allowed to be attached to and detached from the upper belt unit 410.

[0048] As described above, in the third state, the upper belt unit 410 is held in a substantially horizontal position, and in this state, it is possible to replace parts such as the upper belt 411, the tension roller 412, the heater 413, and the sensor, as well as to perform cleaning and oiling operations. This makes it unnecessary to remove the upper door or the exterior cover, and significantly improves maintainability.

[0049] [Lower belt unit part replacement work] Next, part replacement and maintenance of the lower belt unit 420 will be described with reference to FIG. 9. The upper door unit 43 is placed in the open position, and the double doors 401, 402 on the front side of the fixing module 4000 are opened. A fixing member (not shown) that fixes the lower belt unit 420 is removed, and the lower belt unit 420 is pulled out to the front side. This pulls out the lower belt unit 420 supported by slide rails 432, 433 whose longitudinal direction is the front-rear direction. In this pulled-out state, the lower belt unit 420 can be subjected to work such as part replacement, cleaning, and lubrication.

[0050] In this embodiment, the slide rails 432, 433 are an example of a second displacement portion, and displace the lower belt unit 420 relative to the device body 400 between a lower storage position stored in the device body 400 and a drawn-out position protruding from the device body 400. Here, the drawn-out position is a position protruding from the device body 400 in the forward direction F in the sheet width direction and allowing the lower belt 421 to be attached to and detached from the lower belt unit 420. The lower belt unit 420 is allowed to move from the lower storage position to the drawn-out position when the upper door unit 43 is located in the open position.

[0051] As described above, according to the fixing module 4000 of the present embodiment, the upper door unit 43 and the upper belt unit 410 can be displaced to the third state in which the upper door unit 43 is located in the open position and the upper belt unit 410 is located in the maintenance position. This allows the upper belt 411 to be attached to and detached from the upper belt unit 410. In this state, it is possible to replace parts such as the upper belt 411, the tension roller 412, the heater 413, and the sensor, and to perform cleaning and oiling work, and it is not necessary to remove the upper door or the exterior cover, and the maintainability is significantly improved. Therefore, the workability during maintenance such as belt replacement can be improved. Furthermore, according to the fixing module 4000 of the present embodiment, the upper belt unit 410 is held in a substantially horizontal position in the third state, so that the workability can be further improved.

[0052] Furthermore, according to the fixing module 4000 of the present embodiment, by pulling out the lower belt unit 420 to the front side, the lower belt 421 can be attached to and detached from the lower belt unit 420. This can improve the workability during maintenance such as belt replacement.

[0053] In the above embodiment, the lower belt unit 420 is provided so as to be able to be pulled out to the front side while remaining in a horizontal position, but the present invention is not limited to this. For example, a case-shaped lower door unit that houses the lower belt unit 420 may be provided rotatably inside the device body 400, and the front side of the lower door unit may be tilted downward to pull the lower belt unit 420 up to a horizontal position. That is, the upper door unit 43 and the upper belt unit 410 and the lower door unit and the lower belt unit 420 may be arranged substantially symmetrically across the sheet conveying surface.

[0054] This configuration will be described in detail. The lower door unit is supported at its rear side rotatably relative to the device body 400. When performing work such as part replacement, cleaning, or oiling of the lower belt unit 420, a handle disposed on the front side of the lower door unit is pulled downward to rotate the lower door unit downward and open the sheet conveying path. The lower belt unit 420 disposed inside the lower door unit is supported rotatably relative to the lower door unit by a rotation shaft provided on the rear side of the lower door unit. By unlocking the locking member that fixes the lower belt unit 420 to the lower door unit and pulling up the lower belt unit 420 by hand, the front side of the lower belt unit 420 rotates upward. The lower belt unit 420 hits a stopper provided on the lower door unit and stops rotating. At this time, the lower belt unit is held in an approximately horizontal position or in a position where the front side is tilted about ±10 degrees from the horizontal plane, and in this state it is possible to replace parts such as the lower belt 421, tension rollers, heaters, and sensors, as well as perform cleaning and lubrication work.

[0055] In the above embodiment, the case where the sheet conveying device is applied to the fixing module 4000 has been described, but the present invention is not limited to this and can be applied to a device having a conveying belt and a rotating body on both sides of the sheet conveying surface. For example, the present invention can be applied to a cooling module 5000 (cooling device).

[0056] In the above embodiment, the present invention has been described as being applied to the inkjet recording system 100 as an image forming apparatus, but is not limited thereto. For example, the present invention can be applied to an electrophotographic image forming apparatus using toner, and the same effects as those of the present embodiment can be obtained. [Explanation of symbols]

[0057] 43...upper door unit (storage section), 44...support shaft (first rotating shaft), 45...gas spring (second urging section), 46...rotating shaft (second rotating shaft), 47...gas spring (first urging section), 50...lock mechanism, 51...stopper (holding section), 100...inkjet recording system (image forming apparatus), 400...apparatus main body (housing), 410...upper belt unit (belt unit, first belt unit), 411...upper belt (conveyor belt, first conveyor belt), 413...heater (heating section), 420...lower belt unit (second belt unit), 421...lower belt (rotating body, second conveyor belt), 432, 433...slide rail (second displacement section), 441...first displacement section (displacement section), 2000...print module (image forming section), 4000...fixing module (sheet conveyor, fixing device)

Claims

1. A sheet conveying device for conveying sheets, The casing and A belt unit having a detachable conveyor belt for transporting sheets, A storage section capable of housing the aforementioned belt unit and having a pivot axis aligned with the sheet transport direction, which can be displaced between a closed position and an open position by rotation relative to the housing, The belt unit has a displacement part that is displaced relative to the storage part to a first position where it is stored in the storage part and a second position where it protrudes from the storage part. The system comprises a rotating body positioned opposite the belt unit when the storage unit is in the closed position and the belt unit is in the first position, and which, together with the conveyor belt, grips and conveys the sheet. The aforementioned storage compartment and the aforementioned belt unit are, A first state in which the storage unit is in the closed position and the belt unit is in the first position, and the sheet is conveyed by the conveyor belt, A second state in which the storage compartment is in the open position and the belt unit is in the first position, and the sheet transport path is open, The storage unit is displaceable to a third state in which the storage unit is in the open position and the belt unit is in the second position, allowing the conveyor belt to be attached to and detached from the belt unit. A sheet conveying device characterized by the following features.

2. The belt unit is positioned vertically above the rotating body. The aforementioned storage compartment can be opened upwards. The sheet conveying device according to feature 1.

3. The pivot shaft is provided on the rear side of the housing, The storage unit is provided so as to be rotatable relative to the housing with respect to the pivot axis. The sheet conveying device according to feature 1.

4. The sheet width direction intersecting the sheet transport direction is the front-to-back direction of the housing. The sheet conveying device according to feature 3.

5. In the third state, the conveyor belt is retractable to the front of the housing. The sheet conveying device according to feature 4.

6. The inclination angle of the front side of the belt unit with respect to the horizontal plane is within ±10 degrees. The sheet conveying device according to feature 5.

7. The belt unit is positioned horizontally in the third state. The sheet conveying device according to feature 6.

8. The pivot shaft is a first pivot shaft, The displacement portion is, A second pivot shaft is provided in the storage section and is aligned with the sheet transport direction, The storage section has a holding section that holds the belt unit in the second position when the storage section is in the open position, The belt unit is provided so as to be displaceable by rotation between the first position and the second position around the second pivot axis. The sheet conveying device according to feature 3.

9. The second pivot shaft is provided on the rear side of the storage section, The sheet conveying device according to feature 8.

10. The displacement portion has a first biasing portion that biases the belt unit toward the first position relative to the storage portion located in the open position. The sheet conveying device according to feature 1.

11. The device includes a locking mechanism that switches between a locked state, which fixes the belt unit to the first position relative to the storage compartment, and a released state, which releases the lock and allows the belt unit to rotate from the first position to the second position. The sheet conveying device according to feature 1.

12. The storage section is further provided with a second biasing section that biases it toward the open position, The second biasing unit is, If the opening angle of the storage compartment is less than or equal to a first angle with respect to the horizontal, the storage compartment and the belt unit have a first biasing force that causes them to rotate to the closed position due to their own weight, If the opening angle of the storage section is two angles or more with respect to the horizontal, a second biasing force is provided to rotate the storage section to the open position. The sheet conveying device according to feature 1.

13. The aforementioned conveyor belt is the first conveyor belt, The aforementioned belt unit is a first belt unit, The displacement portion is the first displacement portion, The rotating body is a second conveyor belt, A second belt unit having the second conveyor belt, The second belt unit comprises a second displacement part that is displaced relative to the housing to a third position in which it is housed in the housing, and a fourth position in which it is pulled out from the housing toward the front of the housing, allowing the second conveyor belt to be attached to and detached from the second belt unit. The second belt unit is permitted to move from the third position to the fourth position when the storage section is in the open position. The sheet conveying device according to feature 2.

14. An image forming unit that ejects ink onto a sheet to form an image, The system includes a sheet transport device that transports a sheet on which an image has been formed by the image forming unit, The sheet conveying device is the sheet conveying device described in any one of claims 1 to 9. An image forming apparatus characterized by the following features.

15. The sheet conveying device has a heating section in the belt unit, and is a fixing device that heats the sheet on which the image is formed between the conveying belt and the rotating body to fix the image to the sheet. The image forming apparatus according to feature 14.

16. A sheet conveying device for conveying sheets, It has a housing that includes an upper unit and a lower unit, The upper unit is positioned between a closed position and an open position by rotating on a pivot axis that rotates in a direction perpendicular to the sheet transport direction. The aforementioned upper unit is capable of housing a belt unit having a belt for transporting the sheet in a detachable manner. The belt unit is positioned in a home position in which the belt unit is housed in the upper unit, and in a separated position in which at least a part of the belt unit is separated from the upper unit. The lower unit has a rotating body that, together with the belt, forms a nip to transport the sheet. The aforementioned enclosure is A first state in which the upper unit is in the closed position and the belt unit is in the home position, A second state in which the upper unit is in the open position and the belt unit is in the home position, The upper unit is displaceable to a third state in which it is in the open position and the belt unit is in the separated position. The housing is displaced from the first state through the second state to the third state, and from the third state through the second state to the first state. The second state is a state in which the belt cannot be attached to or detached from the belt unit. The third state is a state in which the belt is detachable from the belt unit. A sheet conveying device characterized by the following features.

17. The pivot shaft is provided on the rear side of the housing, The upper unit is rotatably mounted relative to the housing around the pivot axis. The sheet conveying device according to feature 16.

18. The sheet width direction intersecting the sheet transport direction is the front-to-back direction of the housing. The sheet conveying device according to feature 17.

19. The inclination angle of the front side of the belt unit with respect to the horizontal plane is within ±10 degrees. The sheet conveying device according to feature 16.

20. The belt unit is positioned horizontally in the third state. The sheet conveying device according to feature 19.

21. A locking mechanism that switches between a locked state in which the belt unit is fixed to the upper unit in the home position, and a released state in which the locked state is released, allowing the belt unit to rotate from the home position to the separated position. The sheet conveying device according to feature 16.

22. An image forming unit that ejects ink onto a sheet to form an image, The system includes a sheet transport device that transports a sheet on which an image has been formed by the image forming unit, The sheet conveying device is the sheet conveying device described in any one of claims 16 to 21. An image forming apparatus characterized by the following features.

23. The sheet conveying device has a heating section in the belt unit, and is a fixing device that heats the sheet on which the image is formed between the belt and the rotating body to fix the image to the sheet. The image forming apparatus according to feature 22.

Images