JP7568463B2 - Conveyor - Google Patents

Description

The present invention relates to a transport device equipped with an opening/closing door that opens the transport path to the outside.

In a conveying device used in an image forming apparatus or the like, in order to perform double-sided printing on media such as paper, a circulation path for inverting the media is provided in the media conveying path. This circulation path is provided with a pair of switchback rollers that temporarily stop the media and nip and convey the media in the reverse direction. One of the switchback rollers is sometimes attached to an opening and closing door that can open the circulation path to clear a jam.

If a media jam occurs during the switchback process in this circulation path (before or after the switchback), and the above-mentioned opening and closing door is opened to clear the jam, the media is no longer nipped by the switchback roller pair.

In this way, if the media is no longer nipped when the door is opened, the media may fall under its own weight and become impossible to remove from the door.

Conventionally, a conveying mechanism has been proposed in which a biasing member such as a leaf spring is provided on the door, and the biasing member clamps the medium when the door is open (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 5-132184

However, in the above-mentioned transport mechanism in which the urging member is provided on the door, when the door is closed to transport the media, a retraction mechanism is required to retract the urging member so as not to interfere with the transport of the media, which complicates the structure and increases costs. In addition, if the urging member is not retracted and is constantly clamped, there are problems in that a sufficient clamping force cannot be obtained to avoid interfering with the transport of the media, or that if the clamping force is made too strong by increasing the urging force, the clamping force can make the media transport unstable.

The object of the present invention is to provide a transport device that can stably transport media that is no longer held by the transport member when the opening and closing door is opened, with a simple configuration.

In one aspect, the transport device includes a first transport member and a second transport member that are arranged opposite each other on a transport path for a medium and transport the medium while nipping it; an opening/closing door to which the second transport member is attached that opens and closes between an open position in which the second transport member is separated from the first transport member and a closed position in which the second transport member is brought closer to the first transport member; and a medium support section that supports the medium on the transport path, the transport path having a curved portion, the medium support section having an abutment member that abuts against the medium, and the opening/closing door opening to the open position clamps the medium, at least a portion of which is located on the curved portion, and is no longer nipped by the first transport member and the second transport member, between the opening/closing door and the opposing transport path.

According to the above aspect, the medium that is no longer held by the conveying member when the door is opened can be stably conveyed with a simple configuration.

1 is a configuration diagram showing an image forming apparatus in which a conveying device according to an embodiment is used; 1 is a control block diagram showing an image forming apparatus in which a conveying device according to an embodiment is used; 1 is an enlarged view showing a circulating conveyance section of an image forming apparatus in which a conveyance device according to an embodiment is used; 1A and 1B are diagrams showing an opening and closing door and the like in a closed position in one embodiment. 1A and 1B are diagrams showing an opening and closing door and the like in an open position in one embodiment. 2 is a perspective view showing a medium support portion and a transport guide according to an embodiment. FIG. 1 is a perspective view showing a medium support portion and a part of a transport guide according to an embodiment. FIG. 1 is a perspective view (part 1) showing a medium support portion according to an embodiment. FIG. 2 is a perspective view (part 2) showing a medium support portion according to an embodiment. FIG. 2 is a front view showing a medium support portion according to an embodiment. 11 is an explanatory diagram illustrating how a sheet is sandwiched by a medium support unit according to an embodiment. FIG. 11 is an explanatory diagram for explaining a feed amount for a clamping region of a sheet according to an embodiment. FIG.

Below, an image forming apparatus using a conveying device according to an embodiment of the present invention will be described with reference to the drawings.

Figure 1 is a diagram showing the configuration of an image forming device 1 that uses a conveying device according to one embodiment.

Figure 2 is a control block diagram showing the image forming device 1.

Figure 3 is an enlarged view showing the circulating transport section 6 of the image forming device 1.

In the following description, the top, bottom, left, and right directions on the paper surface of FIG. 1 are referred to as the top, bottom, left, and right directions, and the direction perpendicular to the paper surface of FIG. 1 is referred to as the front, back, and right directions. In addition, in the following description, upstream and downstream refer to upstream and downstream on the transport path.

In FIG. 1, the transport path for transporting paper P, which is an example of a medium, is indicated by a thick line. Among the transport paths, the print path RP is indicated by a solid line, the circulation path RC is indicated by a dashed line, the first discharge path RD1 and the second discharge path RD2 are indicated by dashed lines, and the external feed path RS1 and the internal feed path RS2 are indicated by dashed two-dot lines. Note that, although paper P is used as an example of a medium, the medium may be a medium made of a material other than paper, or a medium with a folded portion such as an envelope.

As shown in Figures 1 and 2, the image forming device 1 includes a housing 2, a paper feed unit 3, a belt platen transport unit 4, a printing unit 5, a circulating transport unit 6, a paper discharge unit 7, an operation panel 15, and a control unit 16. The paper feed unit 3, the belt platen transport unit 4, the circulating transport unit 6, and the paper discharge unit 7 function as an example of a transport unit that transports paper P (medium).

The housing 2 shown in FIG. 1 houses or holds each part of the image forming device 1. The housing 2 has a front door 17 shown by a dashed line in FIG. 1. This front door 17 opens and closes the front of the housing 2. By opening the front door 17, the user can access the inside of the image forming device 1.

The paper feed unit 3 feeds unprinted paper P to the belt platen transport unit 4. The paper feed unit 3 also re-feeds paper P after one-sided printing to the belt platen transport unit 4 during double-sided printing. The paper feed unit 3 has an external paper feed tray 21, an external paper feed roller 22, first and second internal paper feed trays 23, 24, first and second internal paper feed rollers 25, 26, first and second internal paper feed motors 27, 28, first to third internal paper feed transport roller pairs 29-31, an internal paper feed transport motor 32, a vertical transport roller pair 33, a vertical transport motor 34, a registration roller pair 35, a registration motor 36, and paper sensors 37-40.

Paper P to be used for printing is loaded on the external paper feed tray 21. The external paper feed tray 21 is installed with a portion exposed to the outside of the housing 2.

The external paper feed roller 22 feeds out the paper P stacked on the external paper feed tray 21 one sheet at a time and transports it along the external paper feed path RS1 toward the registration roller pair 35.

Paper P to be used for printing is loaded on the first and second internal paper feed trays 23 and 24. The second internal paper feed tray 24 is disposed below the first internal paper feed tray 23. The first and second internal paper feed trays 23 and 24 are disposed inside the housing 2.

The first internal paper feed roller 25 feeds out the paper P stacked on the first internal paper feed tray 23 one sheet at a time and transports it to the first internal paper feed transport roller pair 29. The second internal paper feed roller 26 feeds out the paper P stacked on the second internal paper feed tray 24 one sheet at a time and transports it to the second internal paper feed transport roller pair 30.

The first internal feed motor 27 shown in FIG. 2 drives the first internal feed roller 25, and the second internal feed motor 28 drives the second internal feed roller 26.

The first internal paper feed conveying roller pair 29 and the second internal paper feed conveying roller pair 30 shown in FIG. 1 convey the paper P fed from the first internal paper feed tray 23 or the second internal paper feed tray 24 by the first internal paper feed roller 25 or the second internal paper feed roller 26, respectively, to the third internal paper feed conveying roller pair 31. The third internal paper feed conveying roller pair 31 conveys the paper P conveyed by the first internal paper feed conveying roller pair 29 or the second internal paper feed conveying roller pair 30 to the vertical conveying roller pair 33. The third internal paper feed conveying roller pair 31 is disposed downstream near the junction of the part of the internal paper feed path RS2 extending from the first internal paper feed roller 25 and the part extending from the second internal paper feed roller 26.

The first internal paper feed conveying roller pair 29, the second internal paper feed conveying roller pair 30, and the third internal paper feed conveying roller pair 31 nip and convey the paper P.

The internal paper feed conveying motor 32 shown in FIG. 2 drives the first to third internal paper feed conveying roller pairs 29 to 31.

The vertical transport roller pair 33 shown in FIG. 1 transports the paper P transported by the first to third internal paper feed transport roller pairs 29-31 along the internal paper feed path RS2 to the registration roller pair 35. The vertical transport roller pair 33 also transports the paper P after single-sided printing that has been transported along the circulation path RC during double-sided printing to the registration roller pair 35. The vertical transport roller pair 33 is disposed along the internal paper feed path RS2 downstream of the point where the circulation path RC joins the internal paper feed path RS2. The vertical transport roller pair 33 transports the paper P while nipping it.

The vertical transport motor 34 shown in FIG. 2 drives the vertical transport roller pair 33. The vertical transport motor 34 also drives the external paper feed roller 22. The vertical transport motor 34 is connected to the vertical transport roller pair 33 and the external paper feed roller 22 via a one-way clutch (not shown). As a result, the vertical transport roller pair 33 is driven by the rotation of the vertical transport motor 34 in one direction, and the external paper feed roller 22 is driven by the rotation of the vertical transport motor 34 in the other direction.

The registration roller pair 35 shown in FIG. 1 temporarily stops the paper P transported by the external paper feed roller 22 or the vertical transport roller pair 33, corrects skew, and then transports the paper to the belt platen transport unit 4. The registration roller pair 35 is disposed on the printing path RP downstream near the junction of the external paper feed path RS1 and the internal paper feed path RS2. The registration roller pair 35 transports the paper P while nipping it.

The registration motor 36 shown in FIG. 2 drives the registration roller pair 35.

As shown in FIG. 1, the paper sensor 37 detects the paper P being fed from the first internal paper feed tray 23 and transported to the third internal paper feed transport roller pair 31. The paper sensor 37 is disposed near the downstream side of the first internal paper feed transport roller pair 29. The paper sensor 38 detects the paper P being fed from the second internal paper feed tray 24 and transported to the third internal paper feed transport roller pair 31. The paper sensor 38 is disposed near the downstream side of the second internal paper feed transport roller pair 30. The paper sensor 39 detects the paper P being transported from the third internal paper feed transport roller pair 31 to the vertical transport roller pair 33. The paper sensor 39 is disposed near the downstream side of the third internal paper feed transport roller pair 31.

The paper sensor 40 detects the paper P being transported from the vertical transport roller pair 33 to the registration roller pair 35. The paper sensor 40 is located near the downstream side of the vertical transport roller pair 33. The paper sensor 41 detects the paper P being transported by the external paper feed roller 22 or the vertical transport roller pair 33 and entering the registration roller pair 35. The paper sensor 41 is located near the upstream side of the registration roller pair 35.

The belt platen transport unit 4 transports the paper P transported from the paper supply unit 2 to the circulating transport unit 6 or the paper discharge unit 7. The belt platen transport unit 4 is disposed downstream of the paper supply unit 2. The belt platen transport unit 4 has a belt platen 46, a belt platen motor 47, and a paper sensor 48.

The belt platen 46 attracts and holds the paper P conveyed by the registration roller pair 35 on the belt and conveys it. The belt platen 46 can be raised and lowered by the lifting and lowering drive unit 52, which will be described later.

The belt platen motor 47 drives the belt of the belt platen 46.

The paper sensor 48 detects the paper P being transported from the registration roller pair 35 to the belt platen 46. The paper sensor 48 is disposed between the registration roller pair 35 and the upstream end of the belt platen 46.

The printing unit 5 prints on the paper P. In this embodiment, an example is described in which the printing method used by the printing unit 5 is an inkjet method, but the printing method is not particularly limited.

The printing unit 5 is disposed above the belt platen 46. The printing unit 5 has a head unit 51 and an elevation drive unit 52.

The head unit 51 prints an image by ejecting ink onto the paper P transported by the belt platen 46. The head unit 51 has multiple inkjet heads 53 and a head holder 54.

The inkjet head 53 has multiple nozzles arranged along the front-to-rear direction (main scanning direction) and ejects ink from the nozzles. The multiple inkjet heads 53 are arranged in parallel along the transport direction (left-to-right direction) of the paper P.

The head holder 54 holds the inkjet head 53. The head holder 54 is fixed at a predetermined position within the housing 2.

The lifting drive unit 52 raises and lowers the belt platen 46. The lifting drive unit 52 is disposed inside the head holder 54. The lifting drive unit 52 has a wire, a pulley, a motor, etc., and supports the belt platen 46 by suspending it with the wire. The lifting drive unit 52 raises and lowers the belt platen 46 by rotating the pulley with the motor to wind and unwind the wire.

The circulating conveying section 6 shown in Figures 1 to 3 conveys the paper P after single-sided printing from the downstream end of the belt platen 46 to the vertical conveying roller pair 33 along the circulating path RC during double-sided printing. The circulating conveying section 6 has first and second intermediate conveying roller pairs 56, 57, an intermediate conveying motor 58, a switchback roller pair 59, a reversing motor 60, first to third horizontal conveying roller pairs 61 to 63, a horizontal conveying motor 64, an upward conveying roller pair 65, an upward conveying motor 66, paper sensors 67 to 70, a medium support section 8, conveying guides 9, 10, 12, and 13, and an opening/closing door 11. Here, the conveying device according to this embodiment includes at least the switchback roller pair 59, the opening/closing door 11, and the medium support section 8. The conveying guides 9, 10, 12, and 13 form part of the conveying path for the medium. Note that in Figure 3, the paper sensors 67 to 70 shown in Figure 1 are omitted.

The first and second intermediate conveying roller pairs 56, 57 shown in Figures 1 and 3 convey the paper P after the front side is printed to the switchback roller pair 59 during double-sided printing. The first and second intermediate conveying roller pairs 56, 57 are arranged along the circulation path RC between the belt platen 46 and the switchback roller pair 59.

The first intermediate conveying roller pair 56 and the second intermediate conveying roller pair 57 nip and convey the paper P. The second intermediate conveying roller pair 57 is disposed downstream of the first intermediate conveying roller pair 56.

The intermediate conveying motor 58 shown in FIG. 2 drives the first and second intermediate conveying roller pairs 56 and 57. The intermediate conveying motor 58 also drives the first post-processing paper discharge roller pair 75 and the first and second paper discharge tray paper discharge roller pairs 78 and 79, which will be described later.

3, the switchback roller pair 59 is disposed downstream of the second intermediate conveying roller pair 57 in the first conveying direction D1 along the circulation path RC. The switchback roller pair 59 is composed of a pair of a first switchback roller 59a and a second switchback roller 59b, as shown in FIG. 4 and FIG. 5, which will be described later with a part of the cover removed to show the second switchback roller 59b, and conveys the paper P while nipping it. The first switchback roller 59a and the second switchback roller 59b are disposed opposite each other in the conveying path of the paper P (in this embodiment, the switchback path RCa for reversing the paper P in the circulation path RC), and are an example of a first conveying member and a second conveying member that convey the paper while nipping it. These first conveying member and second conveying member may be conveying members other than rollers, such as belts.

As shown in FIG. 3, the switchback roller pair 59 switches back the paper P that has been transported in the first transport direction D1 by the second intermediate transport roller pair 57 on the switchback route RCa of the circulation route RC, and transports it in the second transport direction D2 to the first horizontal transport roller pair 61. The second switchback roller 59b is attached to the opening and closing door 11, which will be described later.

The reversing motor 60 shown in FIG. 2 drives the first switchback roller 59a of the switchback roller pair 59.

The first to third horizontal conveying roller pairs 61 to 63 shown in Figures 1 and 3 convey the paper P switched back by the switchback roller pair 59 to the upward conveying roller pair 65. The first to third horizontal conveying roller pairs 61 to 63 are arranged along the upstream portion of the circulation route RC between the switchback roller pair 59 and the junction point of the circulation route RC with the internal paper feed route RS2.

The first horizontal conveying roller pair 61, the second horizontal conveying roller pair 62, and the third horizontal conveying roller pair 63 nip and convey the paper P. The second horizontal conveying roller pair 62 is disposed downstream of the first horizontal conveying roller pair 61. The third horizontal conveying roller pair 63 is disposed downstream of the second horizontal conveying roller pair 62.

The horizontal conveying motor 64 shown in FIG. 2 drives the first and second horizontal conveying roller pairs 61 and 62. The third horizontal conveying roller pair 63 is driven by the lifting conveying motor 66.

The ascending conveying roller pair 65 shown in Figures 1 and 3 conveys the paper P conveyed by the first to third horizontal conveying roller pairs 61 to 63 to the vertical conveying roller pair 33. The ascending conveying roller pair 65 is disposed along the downstream portion of the circulation path RC between the switchback roller pair 59 and the junction of the circulation path RC with the internal paper feed path RS2. The ascending conveying roller pair 65 conveys the paper P while nipping it.

The upward conveying motor 66 shown in FIG. 2 drives the upward conveying roller pair 65 and the third horizontal conveying roller pair 63.

As shown in FIG. 1, the paper sensors 67, 68 detect the paper P being transported to the switchback roller pair 59 by the first and second intermediate transport roller pairs 56, 57. The paper sensors 67, 68 are disposed downstream near the first intermediate transport roller pair 56 and the second intermediate transport roller pair 57, respectively. The paper sensors 68, 69 detect the paper P being transported to the vertical transport roller pair 33 along the circulation path RC after being switched back by the switchback roller pair 59. The paper sensors 68, 69 are disposed downstream near the first horizontal transport roller pair 61 and the upward transport roller pair 65, respectively.

The medium support section 8, transport guides 9, 10, 12, and 13, and opening/closing door 11 shown in Figure 3 will be described later.

The paper discharge unit 7 shown in Figures 1 and 2 discharges printed paper P. The paper discharge unit 7 has switching units 71, 72, solenoids 73, 74, first and second post-processing paper discharge roller pairs 75, 76, a post-processing paper discharge motor 77, first to third paper discharge tray paper discharge roller pairs 78-80, a paper discharge tray paper discharge motor 81, paper sensors 82-85, and a paper discharge tray 86.

The switching unit 71 shown in FIG. 1 switches the transport path of the paper P between the first discharge path RD1 and the circulation path RC. The first discharge path RD1 is a path that extends from the downstream end of the printing path RP toward a post-processing device (not shown) that is disposed on the right side of the image forming device 1. The switching unit 71 is disposed at the branching point of the first discharge path RD1 and the circulation path RC.

The switching unit 72 switches the transport path of the paper P between the first paper discharge path RD1 and the second paper discharge path RD2. The second paper discharge path RD2 is a path that branches off from the first paper discharge path RD1 downstream of the branch point between the first paper discharge path RD1 and the circulation path RC and heads toward the paper discharge tray 86. The switching unit 72 is disposed at the branch point where the second paper discharge path RD2 branches off from the first paper discharge path RD1.

Solenoids 73 and 74 shown in FIG. 2 drive switching units 71 and 72, respectively.

The first and second post-processing discharge roller pairs 75, 76 shown in FIG. 1 discharge the paper P conveyed from the belt platen 46 to the post-processing device. The first and second post-processing discharge roller pairs 75, 76 are arranged along the first discharge path RD1.

The first post-processing discharge roller pair 75 and the second post-processing discharge roller pair 76 nip and transport the paper P. The second post-processing discharge roller pair 76 is disposed downstream of the first post-processing discharge roller pair 75.

The post-processing discharge motor 77 shown in FIG. 2 drives the second post-processing discharge roller pair 76. The first post-processing discharge roller pair 75 is driven by the intermediate conveyance motor 58.

The first to third paper discharge tray discharge roller pairs 78-80 shown in FIG. 1 discharge the paper P conveyed from the belt platen 46 onto the paper discharge tray 86. The first to third paper discharge tray discharge roller pairs 78-80 are arranged along the second paper discharge path RD2.

The first paper output tray discharge roller pair 78, the second paper output tray discharge roller pair 79, and the third paper output tray discharge roller pair 80 nip and transport the paper P. The second paper output tray discharge roller pair 79 is disposed downstream of the first paper output tray discharge roller pair 78. The third paper output tray discharge roller pair 80 is disposed downstream of the second paper output tray discharge roller pair 79.

The paper discharge tray discharge motor 81 shown in FIG. 2 drives the third paper discharge tray discharge roller pair 80. The first and second paper discharge tray discharge roller pairs 78, 79 are driven by the intermediate conveying motor 58.

As shown in FIG. 1, the paper sensor 82 detects the paper P transported along the first discharge path RD1. The paper sensor 82 is disposed downstream near the first post-processing discharge roller pair 75. The paper sensors 83-85 detect the paper P transported along the second discharge path RD2. The paper sensor 83 is disposed between the branch point of the second discharge path RD2 from the first discharge path RD1 and the first discharge tray discharge roller pair 78. The paper sensor 84 is disposed downstream near the second discharge tray discharge roller pair 79. The paper sensor 85 is disposed upstream near the third discharge tray discharge roller pair 80.

The paper P discharged by the first to third paper discharge roller pairs 78 to 80 is stacked on the paper discharge tray 86. The paper discharge tray 86 is disposed at the downstream end of the second paper discharge path RD2.

The operation panel 15 displays various input screens and accepts input operations by the user. The operation panel 15 has a display unit 91 and an input unit 92.

The display unit 91 has, for example, a liquid crystal display panel and displays various input screens, etc.

The input unit 92 accepts input operations by the user and outputs operation signals corresponding to the operations. The input unit 92 has various operation keys, a touch panel, etc.

The control unit 16 has a processor (e.g., a CPU: Central Processing Unit) that functions as an arithmetic processing device, and a storage unit (e.g., a memory) such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and controls the operation of the entire image forming device 1.

Figure 4 shows the opening and closing door 11 etc. in the closed position C1.

Figure 5 shows the opening and closing door 11 etc. in the open position C2.

Figure 6 is a perspective view showing the medium support section 8 and the transport guides 9, 10, 12, and 13.

Figure 7 is a perspective view showing the medium support section 8 and some of the transport guides 9 and 12.

Figures 8 and 9 are perspective views showing the medium support section 8.

Figure 10 is a front view showing the medium support section 8.

In FIG. 6, the transport guide 10 is shown transparently to show a portion of the medium support section 8 that is hidden by the transport guide 10.

As shown in Figures 8 to 10, the medium support section 8 has a contact member 8a and an elastic body 8b. As shown in Figures 6 and 7, two medium support sections 8 are arranged side by side in the front-to-rear direction. The number of medium support sections 8 can be any number equal to or greater than one.

The abutting member 8a is attached to the elastic body 8b and abuts against the paper P. The abutting member 8a is, for example, a non-elastic body such as plastic. As shown in Figs. 4 and 5, the abutting member 8a has a block shape in which the thickness in the entry direction (first transport direction D1) and in the direction perpendicular to the transport guide 10 (thickness in the left-right direction) gradually increases and then decreases as the abutting member 8a advances in the entry direction. Alternatively, the abutting member 8a has a shape in which the contact area with the paper P increases as the abrasion due to the sliding of the paper P progresses. For example, the abutting member 8a has a triangular prism shape in which one side is parallel to the vertical direction in the front view of Figs. 4 and 5 and the tip (apex in the front view) which is the right end on the opposite side is located on the transport guide 10 side. The tip of the abutting member 8a is rounded to form a curved surface portion. The contact member 8a may be configured to have a triangular prism shape, so that the guide gap between the gripping area A (see FIG. 12), which is the pressing point with the transport guide 10, gradually decreases (angle θ1) toward the paper P's entry direction (first transport direction D1), as shown in FIG. 11 described later. The contact member 8a may also be configured to have a guide surface such that the guide gap between the gripping area A with the transport guide 10 gradually decreases (angle θ2) toward the opposite direction to the entry direction (second transport direction D2). These angles θ1 and θ2 are preferably 45 degrees or less with respect to the paper P, and more preferably 30 degrees or less. In other words, the contact member 8a gradually decreases the guide gap between the gripping area A and the transport path (switchback path RCa) toward both the entry direction (first transport direction D1) and the opposite direction of the paper P. The contact member 8a may be a driven roller or the like.

The elastic body 8b is, for example, a leaf spring, and the abutment member 8a is attached to the lower right side surface. The upper right side surface of the elastic body 8b is also fixed to the left side surface of the transport guide 9 by, for example, gluing.

As shown in Figures 4 to 6, of the transport guides 9, 10, 12, and 13, the transport guides 9, 12, and 13 are arranged on the left side of the switchback route RCa in the order of transport guide 12, transport guide 9, and transport guide 13 from upstream in the first transport direction D1, and the transport guide 10 is arranged to face the transport guide 9 and transport guide 13 on the right side of the switchback route RCa.

The transport guide 9 has two rectangular openings 9a arranged side by side in the front-to-rear direction for passing the two contact members 8a through.

The transport guide 10 has a curved portion 10a that curves horizontally from a vertical downward direction toward the first transport direction D1. This means that the transport path of the paper P (the switchback path RCa of the circulation path RC) also has a curved portion 10a. This curved portion 10a accommodates at least a portion of the paper P at the switchback position where the transport direction is switched from the first transport direction D1 to the second transport direction D2 by the first switchback roller 59a and the second switchback roller 59b. Note that the above-mentioned medium support section 8 (contact member 8a) holds the paper P between itself and the transport guide 10 at the curved portion 10a.

The transport guide 12 curves vertically downward from the horizontal direction toward the first transport direction D1.

The transport guide 13 is positioned to face the transport guide 10 in the horizontal portion at the back of the switchback route RCa. Note that in Figures 4 to 6, a large gap is provided between the transport guide 13 and the transport guide 9, but a transport guide may also be placed in this gap.

The opening and closing door 11 shown in FIG. 4 and FIG. 5 is a door for a user to access the circulation path RC including the switchback path RCa, for example, to clear a jammed paper P after the jam occurs, and is opened and closed manually or automatically by the user. In addition, the opening and closing door 11 is equipped with the second switchback roller 59b as described above. As a result, when the opening and closing door 11 is opened to the open position C2 shown in FIG. 5, it opens the switchback path RCa to the outside of the housing 2 or the image forming device 1, and separates the second switchback roller 59b from the first switchback roller 59a. In addition, when the opening and closing door 11 is closed to the closed position C1 shown in FIG. 4, it closes the switchback path RCa and moves the second switchback roller 59b closer to the first switchback roller 59a, transitioning the switchback roller pair 59 to a state in which it can nip the paper P.

The opening and closing door 11 is in a vertical state in the closed position C1 as shown in FIG. 4, and closes the switchback route RCa. Also, the opening and closing door 11 rotates clockwise around the rotating shaft at the lower end as the center of rotation until it becomes horizontal, and is in a horizontal state in the open position C2 as shown in FIG. 5, although this is just one example.

The medium support unit 8 is disposed downstream of the switchback roller pair 59 in the first transport direction D1, and sandwiches the paper P between the transport guide 10 and the medium support unit 8, which is no longer nipped by the switchback roller pair 59 when the door 11 is opened to the open position C2. The medium support unit 8 sandwiches the paper P between the transport guide 10 whether the door 11 is in the closed position C1 or the open position C2. In other words, the medium support unit 8 is always in a state in which it can sandwich the paper P between the transport guide 10. However, the medium support unit 8 may be provided on the door 11, for example, and move to a position where it sandwiches the paper P between the transport guide 10 in conjunction with the movement of the door 11 to the open position C2.

In addition, since the medium support unit 8 holds the paper P between itself and the transport guide 10 at the curved portion 10a of the switchback path RCa (transport guide 10) as described above, it can be said that at least a portion of the paper P held by the medium support unit 8 and the transport guide 10 is located in the curved portion 10a. Even if the medium support unit 8 holds the paper P upstream of the curved portion 10a in the first transport direction D1, the medium support unit 8 can hold the paper P, part of which is located in the curved portion 10a, between itself and the transport guide 10 as long as it is away from the curved portion 10a by less than the length of the maximum size paper P used in the image forming device 1. The medium support unit 8 is preferably positioned to hold the paper P located in the curved portion 10a between itself and the transport guide 10 for at least half, more preferably at least two-thirds, of the length in the first transport direction D1.

The curved portion 10a accommodates at least a portion of the paper P at the switchback position where the switchback roller pair 59 switches the transport direction from the first transport direction D1 to the second transport direction D2. However, the curved portion 10a where at least a portion of the paper P is located when it is sandwiched between the medium support unit 8 and the transport guide 10 may be provided on a transport path other than the switchback path RCa.

The printing operation of the image forming device 1 is described below.

When a print job is input, the control unit 16 shown in Figures 1 and 2 controls the paper feed unit 3, the belt platen transport unit 4, the circulating transport unit 6, and the paper discharge unit 7 to feed, transport, and discharge paper P. The control unit 16 also performs a predetermined image processing on the image data included in the print job, and then controls the inkjet head 53 of the head unit 51 to eject ink onto the paper P transported by the belt platen 46 to print an image based on the image data that has been subjected to the image processing.

In the case of single-sided printing, as shown in FIG. 1, in the paper feed unit 3, unprinted paper P is sequentially fed from either the external paper feed tray 21 or the first and second internal paper feed trays 23, 24, and is sequentially fed at a timing such that each paper P is transported at a predetermined interval on the belt platen 46. The fed paper P is printed with ink ejected from the inkjet head 53 while being transported at a predetermined print transport speed on the belt platen 46. The printed paper P is discharged by the paper discharge unit 7.

When the discharge destination is the post-processing device, the printed paper P is guided to the first discharge path RD1 by the switching units 71 and 72. The paper P is then discharged to the post-processing device by the first and second post-processing discharge roller pairs 75 and 76. When the discharge destination is the paper output tray 86, the printed paper P is guided to the second discharge path RD2 by the switching units 71 and 72. The paper P is then discharged to the paper output tray 86 by the first to third paper output tray discharge roller pairs 78 to 80.

When double-sided printing is performed, the paper feed unit 3 sequentially feeds unprinted paper P at a timing that is twice as long as the feeding timing for single-sided printing. The fed paper P is printed while being transported by the belt platen 46, in the same way as when single-sided printing is performed.

After single-sided printing, the paper P is guided to the circulation path RC by the switching unit 71 and transported to the switchback roller pair 59 by the first and second intermediate transport roller pairs 56, 57. When the paper P reaches the switchback roller pair 59, it is switched back by the switchback roller pair 59. During this transport of the paper P, the medium support unit 8 holds the paper P between itself and the transport guide 10 as described above.

Next, the paper P is transported to the vertical transport roller pair 33 by the first to third horizontal transport roller pairs 61 to 63 and the upward transport roller pair 65. The paper P is then re-fed to the belt platen 46 by the vertical transport roller pair 33 and the registration roller pair 35.

Here, the paper P after single-sided printing is refed at a timing such that it is sent to the belt platen 46 alternately with the unprinted paper P that is fed sequentially. As described above, in double-sided printing, the time between the feeding timing of each paper P is twice as long as in single-sided printing. For this reason, it is possible to insert paper P after single-sided printing between unprinted paper P, and refed paper P after single-sided printing alternately with the feeding of unprinted paper P.

After printing on one side, the paper P is switched back by the switchback roller pair 59 and then sent to the belt platen 46 with the unprinted side facing up. After printing on one side, the paper P is printed on the unprinted side while being transported by the belt platen 46. Then, the paper P that has been printed on both sides is discharged by the paper discharge section 7 to the post-processing device or the paper discharge tray 86.

As described above, in double-sided printing, the feeding of unprinted paper P is alternated with the re-feeding of paper P after single-sided printing, so that printing on one side of unprinted paper P and printing on the unprinted side of paper P after single-sided printing are alternated on the belt platen 46. This allows double-sided printing to be performed with the same productivity per side as when printing on one side.

When the error between the detection timing of the paper P and its theoretical value in at least one of the paper sensors 37-40, 48, 67-70, and 82-85 exceeds a threshold value, the control unit 16 determines that a paper jam has occurred in the transport path.

If a jam occurs while the paper P is being switched back on the switchback path RCa, the control unit 16 can determine whether or not the paper P is present in the area opened by the opening and closing door 11, particularly based on the timing of detection of the paper P by the paper sensors 68 and 69.

Then, the control unit 16 stops the transport of the paper P. Specifically, the control unit 16 stops the operation of the paper feed unit 3, the belt platen transport unit 4, the circulating transport unit 6, and the paper discharge unit 7.

When the transport of the paper P stops, the control unit 16 causes the display unit 91 to display a jam clearance screen (not shown). The jam clearance screen is a screen that notifies the user to remove any paper P remaining on the transport path. The jam clearance screen instructs the user to open the opening and closing door 11 or any other opening and closing door that is located in another location as needed, and remove the paper P. The user looks at the jam clearance screen and performs the task of clearing the jam, which is to remove any paper P remaining on the transport path.

If there is paper P nipped by the switchback roller pair 59 at the time the jam occurs, when the opening and closing door 11 opens to the open position C2 as shown in FIG. 5, the nipping of the paper P by the switchback roller pair 59 is released. However, since the paper P is transported while being held between the medium support section 8 and the transport guide 10, it continues to be held between the medium support section 8 and the transport guide 10. Therefore, the paper P does not fall along the switchback path RCa. The holding of the paper P at this time will be described with reference to FIG. 11 and FIG. 12.

Figure 11 is an explanatory diagram for explaining how the medium support section 8 holds the paper P.

Figure 12 is an explanatory diagram for explaining the feed amount of paper P to the clamping area A.

As described above, in a configuration in which the paper P is always clamped by the medium support section 8 and the transport guide 10 even when the opening/closing door 11 is in the closed position C1 shown in FIG. 4, if the clamping force with which the medium support section 8 and the transport guide 10 shown in FIG. 11 clamp the paper P is too strong, the contact member 8a of the medium support section 8 may wear out, the paper P may be damaged, or transport resistance may occur. On the other hand, if the clamping force is weak, the paper P may fall when the opening/closing door 11 is in the open position C2 shown in FIG. 5.

In this regard, in the present embodiment, at least a portion of the paper P held between the medium support unit 8 and the transport guide 10 is located in the curved portion 10a. For example, if the paper P is thick paper with a basis weight of 60 grams or more per square meter, a strong repulsive force due to bending stiffness (bending strength) acts on the curved portion 10a as it tries to return to a flat state from the curved state, and the paper P is pressed against the curved portion 10a, increasing friction, so that the paper P is prevented from falling even with a weak clamping force. This repulsive force can be made stronger the smaller the radius of curvature of the curved portion 10a or the wider the area where the paper P is located in the curved portion 10a.

For example, in the case of ordinary paper or thin paper with a basis weight of less than 60 grams per square meter and weak stiffness, the repulsive force that attempts to return the paper P from the curved state to a flat state at the curved portion 10a is relatively weak, but because the weight of the paper P is relatively small, even a weak clamping force prevents the paper P from falling.

When the medium support section 8 and the transport guide 10 clamp the upstream portion of the paper P in the first transport direction D1, which is the direction of entry into the switchback path RCa (see clamping area A in FIG. 12), and the entire paper P is located in the curved portion 10a, if the short side direction of the paper P is parallel to the first transport direction D1 as shown in the left diagram of FIG. 12, the feed amount of the paper P from the clamping area A is small and the area located in the curved portion 10a is narrow. On the other hand, if the long side direction of the paper P is parallel to the first transport direction D1 as shown in the right diagram of FIG. 12, the feed amount of the paper P from the clamping area A is large and the area located in the curved portion 10a is wide.

When the paper P is held between the medium support section 8 and the transport guide 10 in this manner, the larger the area in which the paper P is located in the curved portion 10a, the stronger the repulsive force that attempts to return the paper P from its curved state to a flat state in the curved portion 10a.

In the present embodiment described above, the conveying device includes a first switchback roller 59a (an example of a first conveying member) and a second switchback roller 59b (an example of a second conveying member), an opening/closing door 11, and a medium support unit 8. The switchback roller pair 59 (the first switchback roller 59a and the second switchback roller 59b) are arranged opposite each other in a switchback path RCa (an example of a conveying path) of a sheet P (an example of a medium), and convey the sheet P while nipping it. The opening/closing door 11 opens and closes between an open position C2 to which the second switchback roller 59b is attached and which separates the second switchback roller 59b from the first switchback roller 59a, and a closed position C1 to which the second switchback roller 59b is brought close to the first switchback roller 59a. The medium support unit 8 supports the sheet P in the conveying path (switchback path RCa). The switchback path RCa has a curved portion 10a. The medium support unit 8 has an abutment member 8a that abuts against the paper P, and when the opening/closing door 11 is opened to the open position C2, the paper P is no longer nipped by the switchback roller pair 59 and at least a portion of the paper P is positioned at the curved portion 10a, and is sandwiched between the opposing transport guide 10 (an example of a transport path). For example, the opening/closing door 11 opens the switchback path RCa to the outside in the open position C2 and closes the switchback path RCa in the closed position C1, and the medium support unit 8 has an elastic body 8b, and the abutment member 8a is attached to the elastic body 8b.

Therefore, even if the opening/closing door 11 is opened to the open position C2 and the paper P is no longer nipped by the first switchback roller 59a and the second switchback roller 59b, a repulsive force due to the bending stiffness (bending strength) of the paper P that tries to return from the curved state at the curved portion 10a to a flat state acts, and the paper P is pressed against the curved portion 10a. Therefore, even if the clamping force between the medium support portion 8 and the transport guide 10 is weak, the paper P can be clamped and prevented from falling to a position where it cannot be removed from the opening/closing door 11. Therefore, it is possible to suppress wear of the medium support portion 8 (contact member 8a), damage to the paper P, and increased transport resistance that would occur if the clamping force between the medium support portion 8 and the transport guide 10 was strengthened. In addition, compared to the case where the elastic body 8b abuts against the paper P, a dedicated abutment member 8a that is abrasion-resistant and has good guiding properties in both forward and backward directions can be installed, which prevents wear on the abutment member 8a through a synergistic effect with the weak clamping force, and makes it easier to prevent a jammed medium, such as an envelope, from getting caught on the abutment member 8a when removing the jammed medium having a folded portion. Furthermore, since the medium support section 8 and the transport guide 10 can clamp the paper P with a weak clamping force, a configuration can be adopted in which the paper P is clamped without retracting the medium support section 8 even during transport of the paper P. When this configuration is adopted, it is possible to omit the retraction mechanism that retracts the medium support section 8 when the opening and closing door 11 is in the closed position C1, and thus to suppress the complication of the structure and the increase in costs.

As described above, according to this embodiment, the paper P (medium) that is no longer held by the switchback roller pair 59 (conveying member) when the opening/closing door 11 is opened can be stably transported with a simple configuration.

In addition, in this embodiment, the transport path of the paper P has a switchback path RCa with a curved portion 10a, and the switchback roller pair 59 nips and transports the paper P in the first transport direction D1, and switches back the paper P and transports it in the second transport direction D2. The curved portion 10a accommodates at least a portion of the paper P at the switchback position where the switchback roller pair 59 switches the transport direction from the first transport direction D1 to the second transport direction D2.

This allows jams to be cleared smoothly on the switchback route RCa, where jams are likely to occur.

In addition, in this embodiment, the medium support unit 8 clamps the paper P between itself and the transport guide 10 at the curved portion 10a.

This makes it possible to increase the area of the paper P that is sandwiched between the medium support unit 8 and the transport guide 10 (part of the transport path) and that is located at the curved portion 10a, thereby further increasing the repulsive force caused by the bending stiffness (bending strength) of the paper P as it tries to return to a flat state from its curved state at the curved portion 10a. This therefore makes it possible to further weaken the clamping force exerted by the medium support unit 8 and the transport guide 10.

In addition, in this embodiment, the guide gap between the contact member 8a and the transport guide 10 (an example of a transport path) for the clamping area A of the paper P gradually decreases in both the entering direction of the paper P (first transport direction D1) and the opposite direction (second transport direction D2).

Therefore, by gradually decreasing the guide gap toward the second transport direction D2, it is possible to prevent the medium having a folded portion, such as an envelope, from getting caught on the contact member 8a when removing the medium, and by gradually decreasing the guide gap toward the first transport direction D1, it is possible to prevent the paper P from getting caught on the contact member 8a during transport.

In addition, in this embodiment, the contact member 8a has a block shape in which the thickness in the direction perpendicular to the transport guide 10 and the approach direction (first transport direction D1) gradually increases and then gradually decreases as the contact member 8a advances in the approach direction. Alternatively, the contact member 8a has a shape in which the contact area with the paper P increases as the contact member 8a becomes worn due to the sliding of the paper P.

As a result, as the contact member 8a wears, the contact area of the contact member 8a with the paper P increases, and the wear rate in the thickness direction becomes relatively slow, which prevents a decrease in the clamping force of the paper P by the medium support section 8 and the transport guide 10.

The present invention is not limited to the above-described embodiment as it is, and the components can be modified and embodied without departing from the gist of the invention in the implementation stage. Various inventions can be formed by appropriately combining the multiple components disclosed in the above-described embodiment. For example, all the components shown in the embodiment may be appropriately combined. Of course, various modifications and applications are possible without departing from the spirit of the invention. The invention described in the claims of the original application is described below.

[Appendix 1]
a first conveying member and a second conveying member disposed opposite each other on a medium conveying path and nipping and conveying the medium;
an opening/closing door to which the second conveying member is attached and which opens and closes between an open position to separate the second conveying member from the first conveying member and a closed position to bring the second conveying member closer to the first conveying member;
a medium support unit that supports the medium in the transport path,
The conveying path has a curved portion,
The medium support section has an abutment member that abuts against the medium, and when the opening/closing door is opened to the open position, the medium is no longer nipped by the first and second conveying members, and at least a portion of the medium is located in the curved portion, and is clamped between the opposing conveying path.

[Appendix 2]
the opening/closing door opens the transport path to the outside at the open position and closes the transport path at the closed position,
2. The transport device according to claim 1, wherein the medium support portion has an elastic body, and the contact member is attached to the elastic body.

[Appendix 3]
the conveying path has a switchback path provided with the curved portion,
the first conveying member and the second conveying member nip and convey the medium in a first conveying direction, and switch back the medium and convey it in a second conveying direction,
The conveying device described in appendix 1 or 2, characterized in that the curved portion accommodates at least a portion of the medium at a switchback position where the conveying direction is switched from the first conveying direction to the second conveying direction by the first conveying member and the second conveying member.

[Appendix 4]
The transport device according to claim 3, wherein the contact member has a guide gap between the transport path and the medium holding area that gradually decreases in both the medium entry direction and the opposite direction.

REFERENCE SIGNS LIST 1 Image forming apparatus 6 Circulating transport section 8 Medium support section 8a Contact member 8b Elastic body 9, 10, 12, 13 Transport guide 9a Opening 10b Curved portion 11 Openable door 59 Switchback roller pair 59a First switchback roller 59b Second switchback roller A Clamping area C1 Closed position C2 Open position D1 First transport direction D2 Second transport direction RC Circulating path RCa Switchback path

Claims (4)

a first conveying member and a second conveying member disposed opposite each other on a medium conveying path and nipping and conveying the medium;
an opening/closing door to which the second conveying member is attached and which opens and closes between an open position to separate the second conveying member from the first conveying member and a closed position to bring the second conveying member closer to the first conveying member;
a medium support unit that supports the medium in the transport path,
The conveying path has a curved portion,
the medium support portion has a contact member that contacts the medium,
A conveying device characterized in that the abutment member does not prevent the medium from being transported along the conveying path even when it abuts against the medium when the opening/closing door is in the closed position, and when the opening/closing door is opened to the open position, the abutment member clamps the medium between the opposing conveying path so that the medium, at least a portion of which is located in the curved portion, is no longer nipped by the first conveying member and the second conveying member and does not fall along the conveying path . the opening/closing door opens the transport path to the outside at the open position and closes the transport path at the closed position,
2. The transport device according to claim 1, wherein the medium support portion has an elastic body, and the contact member is attached to the elastic body. the conveying path has a switchback path provided with the curved portion,
the first conveying member and the second conveying member nip and convey the medium in a first conveying direction, and switch back the medium and convey it in a second conveying direction,
3. The transport device according to claim 1, wherein the curved portion accommodates at least a portion of the medium at a switchback position where the transport direction is switched from the first transport direction to the second transport direction by the first transport member and the second transport member. 4. The transport device according to claim 3, wherein the contact member has a guide gap between the transport path and the medium holding area that gradually decreases in both the medium entry direction and the opposite direction.

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