Paper conveying device and image forming apparatus

Abstract

To provide a paper conveying device and an image forming apparatus for, when a transport direction of paper is reversed, preventing a hindrance to guiding curled paper by providing a guide member that is adjacent to a gate for guiding paper to a reversal path and that operates in conjunction with the gate.SOLUTION: An image forming apparatus according to the present invention includes: a first paper discharge path for discharging paper to a pair of discharge rollers 28; a second paper discharge path for discharging paper to a pair of switchback rollers 27; a gate 23 that allows for switching a path between the first and second paper discharge paths and, when the transport direction of paper is reversed in the second discharge path, guides the paper to a reversal path; and a guide member 24 that is adjacent to the gate 23 and operates in conjunction with the gate 23.SELECTED DRAWING: Figure 7A

Description

[Technical field]

[0001] The present disclosure relates to a paper transport device and an image forming apparatus. [Background technology]

[0002] A conventional paper transport device of an image forming apparatus capable of double-sided printing is configured to switch between a paper transport path when double-sided printing is not performed and a paper transport path when double-sided printing is performed, and is known to have a switching gate for switching the transport path (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-13279 A Summary of the Invention [Problem to be solved by the invention]

[0004] The paper transport device of a conventional image forming device capable of double-sided printing has been configured as described above. In the paper transport device disclosed in Patent Document 1, a large space is required for the switching gate to swing in order to switch the paper transport path, so when curled paper is passed through, the leading edge of the curled paper gets caught in the large space, causing problems in guiding the paper.

[0005] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide a paper transport device and an image forming apparatus that do not interfere with guiding curled paper. [Means for solving the problem]

[0006] The conveying device of the present disclosure has a first discharge path for discharging paper, a second discharge path for discharging paper, and is switchable between the first and second discharge paths, and has a gate for guiding the paper to a reversal path when the conveying direction of the paper is reversed in the second discharge path, and is provided with a guide member adjacent to the gate and linked to the gate.

[0007] Preferably, the guide member is displaced relative to the gate so as to narrow the gap between the gate and the guide member on the upstream side in the paper transport direction when the gate switches the destination of the paper to the first paper discharge path, and to widen the gap between the gate and the guide member on the upstream side in the paper transport direction when the gate switches the destination of the paper to the second paper discharge path.

[0008] More preferably, when the gate switches the transport destination of the paper to the reverse path, the guide member is displaced relative to the gate so as to widen a gap between the gate and the guide member on the upstream side in the paper transport direction.

[0009] Each of the guide member and the gate is supported by a fulcrum provided downstream in the paper transport direction, and the lower end of the guide member abuts against a gate stopper provided on the gate or a main body stopper provided on the main body that holds the gate, and when the guide member abuts against the gate stopper, the gap between the gate and the guide member upstream in the paper transport direction becomes narrower, and when the guide member abuts against the main body stopper, the gap between the gate and the guide member upstream in the paper transport direction becomes wider.

[0010] In another aspect of the present disclosure, an image forming apparatus includes any one of the conveying devices described above. Effect of the Invention

[0011] According to the present disclosure, a paper transport device and an image forming apparatus can be provided that, when the paper transport direction is reversed, does not interfere with guiding curled paper by providing a guide member that is adjacent to the gate that guides the paper to the reversal path and that works in conjunction with the gate.

[0012] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description of the embodiments with reference to the drawings. [Brief description of the drawings]

[0013] [Figure 1A] 1 is a perspective view illustrating an external appearance of an image forming apparatus according to an embodiment of the present disclosure. [Figure 1B] 1B is a cross-sectional view showing an internal configuration of the image forming apparatus shown in FIG. 1A as viewed from the front side. [Figure 2A] 1 is a perspective view showing a state in which a right door of an image forming apparatus according to an embodiment of the present disclosure is open; [Figure 2B] 2B is a cross-sectional view showing a state in which a right door is opened as viewed from the front side of the image forming apparatus shown in FIG. 2A. [Figure 3A] 1 is a diagram showing a paper transport path of an image forming apparatus according to an embodiment of the present disclosure; [Figure 3B] 3B is an enlarged view of the main part of FIG. 3A showing the details of the paper transport path. FIG. [Figure 4A] FIG. 2 is a perspective view showing the main body side with the right door open. [Figure 4B] FIG. 3C is a perspective view showing the state of the gate shown in FIG. 3B, showing a state in which the gate transports a sheet to a discharge sheet transport path. [Figure 4C] FIG. 3C is a perspective view showing the state of the gate shown in FIG. 3B, showing a state in which the gate transports paper to a paper re-feed path. [Figure 5A] FIG. [Figure 5B] FIG. 5B is an enlarged perspective view of a guide member that is a part of FIG. 5A. [Figure 5C] FIG. 4 is a perspective view showing a gate stopper of the gate and a stopper on the main body side. [Figure 6A] 4C is a diagram showing a state in which the gate conveys the paper to the switchback roller pair as shown in FIG. 4B. [Figure 6B] 4D is a diagram showing a state in which the gate conveys the paper to a pair of discharge rollers as shown in FIG. 4C. FIG. [Figure 6C]FIG. 6C is a diagram showing the rotation fulcrum of the gate shown in FIGS. 6A and 6B. [Figure 7A] FIG. 13 is a diagram showing the operating states of the gate and guide member when the paper transported from the fixing section passes through a pair of discharge rollers to be discharged to the paper discharge section, and when the paper is transported from the pair of switchback rollers to a switchback transport path for double-sided printing. [Figure 7B] 13A and 13B are diagrams illustrating the operation states of the gate and the guide member when the paper transported from the fixing unit is transported to a pair of switchback rollers for double-sided printing. [Figure 7C] FIG. 8 is a diagram showing a configuration for keeping a constant distance between the gate and the guide member in FIGS. 7A and 7B. [Figure 7D] FIG. 8 is a diagram showing a configuration for keeping a constant distance between the gate and the guide member in FIGS. 7A and 7B. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] [First embodiment] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. Fig. 1A is a perspective view showing the appearance of an image forming apparatus according to an embodiment of the present disclosure, and Fig. 1B is a cross-sectional view showing the internal configuration of the image forming apparatus shown in Fig. 1A as viewed from the front side. With reference to Figs. 1A and 1B, an image forming apparatus 50 includes an apparatus main body 55, an image forming unit 11 provided in the center of the apparatus main body 55, an image reading unit 51 provided in the upper part of the apparatus main body 55, an operation unit 52 provided on the front side of the apparatus main body 55, and a cassette 53 provided in the lower part of the apparatus main body 55 and supplying paper (not shown) to the image forming unit 11.

[0015] Fig. 2A is a perspective view showing a state in which a right door of an image forming apparatus according to an embodiment of the present disclosure is open, and Fig. 2B is a cross-sectional view showing a state in which the right door is open as viewed from the front side of the image forming apparatus shown in Fig. 2A. With reference to Figs. 2A and 2B, the image forming apparatus 50 includes a right door 54 that can be opened and closed to the right as viewed from the front side where the operation unit 52 is provided from the apparatus main body 55, with the lower part of the apparatus main body 55 as a fulcrum. In Fig. 2B, a gate 23 is provided in the apparatus main body 55, and a guide member (guiding member) 24 is provided in the right door 54, the details of which will be described later.

[0016] The reason why the image forming apparatus 50 is provided with the right door 54 which can be opened and closed in this manner is that, as will be described later, the paper transport path is divided by the right door 54, thereby making it easy to clear paper jams that may occur during the transport of paper (not shown).

[0017] Fig. 3A is a diagram showing a paper transport path of an image forming apparatus according to an embodiment of the present disclosure, and Fig. 3B is an enlarged diagram showing the details of the paper transport path, in which a main part of Fig. 3A is enlarged. Referring to Fig. 3A, the paper transport path 10 of the image forming apparatus 50 includes an ejection paper transport path 14 that prints an image formed by the image forming unit 11 on paper (not shown) from a cassette 53 provided at the bottom and heads toward an ejection roller pair 28 that ejects the paper to a paper ejection unit 13 provided at the top, and a re-feed path 20 consisting of a plurality of roller pairs that switchback the paper by a switchback roller pair 27 to turn the paper over and print the back side, and transports the paper again to the ejection paper transport path 14.

[0018] Also, in order to switch between the discharge paper transport path 14 and the re-feed path 20, a gate 23 is provided immediately before the discharge roller pair 28 and the switchback roller pair 27. Therefore, on the downstream side of the gate 23 in the paper transport direction, there are provided a paper discharge path to the discharge roller pair 28 (first paper discharge path), and a paper discharge path to the switchback roller pair 27 that switches back the paper and transports it again to the discharge roller pair 28 in order to turn the paper over and print on the back side. Note that the guide member 24 provided near the gate 23 is omitted here.

[0019] In Figure 3A, of the elements consisting of multiple roller pairs that make up the paper re-feed path 20, the rollers on the right side of each roller pair (the rollers located to the right of the dotted line indicating the paper re-feed path 20) are provided in the right door 54 shown in Figures 2A and 2B, and the rollers on the left side are provided in the device main body 55.

[0020] The image forming unit 11 includes a transfer belt 16, a drive roller 17 that drives the transfer belt 16, and a secondary transfer roller 18 that is disposed opposite the drive roller 17 and transfers an image onto a sheet of paper.

[0021] The discharge paper transport path 14 includes a drive roller 17 and a secondary transfer roller 18 that constitute the image forming unit 11, a fixing unit 19 arranged downstream in the paper transport direction and consisting of at least one roller, a pair of transport rollers 22 arranged downstream of the above, a gate 23 arranged downstream of the above, and a pair of discharge rollers 28 arranged downstream of the above.

[0022] Next, a description will be given of the configuration in the vicinity of gate 23. Referring to Fig. 3B, gate 23 has a function of branching a paper transport path (not shown) that guides paper to discharge roller pair 28 or switchback roller pair 27, and a function of reversing paper that guides paper to refeed path 20, and below it are provided discharge paper transport path 14 and refeed path 20, and above gate 23 are connected the paper discharge path to discharge roller pair 28 and the paper discharge path to switchback roller pair 27.

[0023] Next, a specific configuration of gate 23 will be described. Fig. 4A is a perspective view showing the main body side with right door 54 open, Fig. 4B is a perspective view showing the state of gate 23 shown in Fig. 3B, showing a state in which gate 23 transports a sheet not shown to switchback roller pair 27, and Fig. 4C is a perspective view showing the state of gate shown in Fig. 3B, showing a state in which gate 23 transports a sheet to discharge roller pair 28 using its lower surface, or transports a sheet to re-feed path 20 using its upper surface, which is the same as the state shown in Fig. 4A.

[0024] In Fig. 3B, the cross section of gate 23 is Y-shaped, but in Fig. 4B and Fig. 4C, the top surface of the gate appears flat because the bottom of the Y-shape of the cross section of gate 23 is not shown.

[0025] With reference to Figures 4A to 4C, gate 23 is a member having a wide width in the paper transport direction, has a recess in the center, and has multiple linear ribs in the paper transport direction that cover the recess.The gate is driven by a solenoid or the like so that its surface has a different posture when transporting paper to the discharge paper transport path 14 (see Figures 3A and 3B) and when transporting paper to the paper re-feed path 20 (see Figures 3A and 3B).

[0026] 4A, semicircular gate stoppers 30 are provided at the bottom of both ends in the width direction of paper transport of gate 23. In addition, a rectangular abutment surface 31 of guide member 24 of right door 54 is provided on the outer side of gate 23 in the paper transport direction.

[0027] Next, the right door 54 will be described. Figures 5A and 5B are perspective views showing the configuration of the right door. Figure 5A is a perspective view showing the right door 54 in an open state. The right door 54 opens so that the upper side rotates and tilts around the lower part of the right door as a fulcrum, but the tilt of the right door 54 is omitted in Figure 5A. Figure 5B is an enlarged perspective view of the guide member 24, which is a part of Figure 5A. Note that Figure 5C is a view showing the gate stopper 30 and the main body side stopper 32 of the gate 23 provided on the main body side, and shows the same part as Figure 4A. With reference to Figures 5A to 5C, the right door 54 is provided with the guide member 24 adjacent to the gate 23 at its upper part and interlocking with the gate 23, and the rectangular abutment surface 25 of the guide member 24 is provided at both ends of its lower part. Also, the gate 23 provided near the guide member 24 is provided with a semicircular gate stopper 30 and a main body side stopper 32 at the lower ends of both ends in the paper conveying direction.

[0028] Next, the contact state between the gate stopper 30 and the main body side stopper 32 will be described. Figures 6A and 6B are views of this contact state as seen from the side of the gate 23 with the right door closed. Figure 6A is a view showing the state in which the gate 23 transports the paper to the switchback roller pair 27 as shown in Figure 4B, in which the lower end of the guide member 24 is stopped by contacting the main body side stopper 32, and the gap between the gate 23 and the guide member 24 on the upstream side in the paper transport direction is set to be wide.

[0029] FIG. 6B is a diagram showing a state in which gate 23, as shown in FIG. 4C, conveys the paper to discharge roller pair 28 using its lower surface, and conveys the paper to paper re-feed path 20 using its upper surface. Guide member 24 is stopped by abutting its lower end against gate stopper 30 provided on gate 23. The gap between the gate 23 and the guide member 24 on the upstream side in the paper transport direction is set to be narrow. Thus, semicircular protrusions or the like are provided as gate stoppers 30 at both ends of the gate in the width direction so that the paper passes through the center between the gate 23 and the guide member 24.

[0030] Figure 6C shows the pivot point 34 of the gate 23 shown in Figures 6A and 6B. A solenoid 35 is provided to switch the gate 23 between the position shown in Figure 6A and the position shown in Figure 6B.

[0031] In the embodiment shown here, the gate 23 and the guide member 24 are each rotatably supported at their upper portions by a respective rotation fulcrum 34 for the gate 23 and a rotation fulcrum 24a for the guide member 24, which are provided downstream in the paper transport direction.

[0032] [Second embodiment] Next, another embodiment will be described. In the above embodiment, the gate 23 and the guide member 24 are provided so as to be rotatable about their respective rotation fulcrums 34 and 24a, but in this embodiment, the upper ends of the gate 23 and the guide member 24 are linked to each other so as to be rotatable with each other by pins (not shown).

[0033] FIG. 7A is a diagram showing the operating states of gate 23 and guide member 24 when paper transported from fixing section 19 in this embodiment passes through discharge roller pair 28 and is discharged to paper discharge section 13, and when paper is transported from switchback roller pair 27 to re-feed path 20 for double-sided printing.

[0034] When a sheet of paper (not shown) transported from fixing unit 19 passes through discharge roller pair 28 and is discharged to paper discharge unit 13 (FIG. 3A), the sheet is transported from bottom to top through the lower part of gate 23 as shown by the arrow in the figure. On the other hand, when a sheet of paper from switchback roller pair 27 is transported to re-feed path 20 for double-sided printing, the sheet is transported from top to bottom as shown by the arrow in the figure, passing between gate 23 and guide member 24. At this time, the upper end of guide member 24 extends to a position where it intersects with the path downstream of switchback roller pair 27 in the transport direction.

[0035] Fig. 7B is a diagram showing the operation state of gate 23 and guide member 24 when a sheet (not shown) transported from fixing unit 19 is transported to switchback roller pair 27 for double-sided printing. In this case, a sheet (not shown) from transport roller pair 22 passes between gate 23 and guide member 24 and is transported to switchback roller pair 27 as indicated by the arrow in the figure. At this time, in order to keep the gap between gate 23 and guide member 24 constant, the lower end of guide member 24 abuts against a main body side stopper (not shown) as in Fig. 6A.

[0036] As shown in Figures 7A and 7B, according to the present disclosure, there is a discharge path (first discharge path) that transports the paper to a pair of discharge rollers 28, a discharge path (second discharge path) that transports the paper to a pair of switchback rollers 27, and the first and second discharge paths can be switched between, and when the transport direction of the paper is reversed in the second discharge path, there is a gate 23 that guides the paper to a reversal path (re-feed path 20), and there is a guide member 24 adjacent to the gate 23 and linked to the gate 23.

[0037] When the gate 23 switches the destination of the paper to an ejection path (first paper ejection path) for transporting the paper to a pair of ejection rollers 28, the guide member 24 narrows the gap between the gate 23 and the guide member 24 on the upstream side in the paper transport direction, and when the gate 23 switches the destination of the paper to an ejection path (second paper ejection path) for transporting the paper to a pair of switchback rollers 27, the guide member 24 displaces relative to the gate 23 so as to widen the gap between the gate 23 and the guide member 24 on the upstream side in the paper transport direction.

[0038] Figures 7C and 7D are diagrams showing a configuration for keeping the gap between gate 23 and guide member 24 in Figures 7A and 7B constant. Referring to Figure 7C, in this case, guide member 24 is provided above gate 23, and a semicircular guide member side stopper 33 protrudes toward gate 23 from the lower end of guide member 24. Here, the semicircular stopper is biased toward gate 23 by a spring (not shown).

[0039] 7D, in this case, guide member 24 is located to the right of gate 23, and the lower end of guide member 24 abuts against main body side stopper 32. Note that, even here, guide member 24 is biased against main body side stopper 32 by a spring (not shown), as indicated by the arrow in the figure.

[0040] When the gate switches the transport destination to the reverse path, the guide member may be displaced relative to the gate so as to widen the gap between the gate and the guide member on the upstream side in the transport direction.

[0041] Also, the guide member adjacent to the gate may be made of a flexible material.

[0042] In the above embodiment, a stopper is provided on either the gate, the guide member, or the main body to maintain the gap between the gate and the guide member, but it may be provided on only one of them.

[0043] The present disclosure can be implemented in various other forms without departing from its spirit or main features. Therefore, the above-described embodiments are merely illustrative and should not be interpreted as being limited. All modifications and variations within the scope of the claims of the present disclosure are within the scope of the present disclosure. [Industrial Applicability]

[0044] According to the present disclosure, it is possible to provide a paper transport device and an image forming apparatus that do not interfere with guiding curled paper, and thus the paper transport device and the image forming apparatus are useful. [Explanation of symbols]

[0045] 10 Paper transport path 11 Image forming section 13 Paper output section 14 Paper ejection path 16 Transfer belt 17 Drive roller 18 Secondary transfer roller 19 Fixing section 20 Refeed path 22 Transport roller pair Gate 23 24 Guide member (guide member) 24a Rotational fulcrum 25,31 Contact surface 27 Switchback roller pair 28 Discharge Roller Pair 30 Gate stopper 32 Body side stopper 33 Guide member side stopper 34 Rotational fulcrum 35 Solenoid 50 Image forming device 51 Image reading unit 52 Operation section 53 Cassette 54 Right Door 55 Device body

Claims

1. a first paper discharge path for discharging paper; a second paper discharge path for discharging the paper; a gate that allows switching between the first discharge path and the second discharge path and guides the paper to a reversing path when a conveying direction of the paper is reversed in the second discharge path; a guide member adjacent to said gate and in communication with said gate.

2. The conveying device described in claim 1, wherein the guide member is displaced relative to the gate so as to narrow a gap between the gate and the guide member on the upstream side of the paper conveying direction when the gate switches the destination of the paper to the first paper discharge path, and to widen a gap between the gate and the guide member on the upstream side of the paper conveying direction when the gate switches the destination of the paper to the second paper discharge path.

3. The conveying device according to claim 1 , wherein when the gate switches the destination of the paper to the inversion path, the guide member displaces relative to the gate so as to widen a gap between the gate and the guide member on the upstream side in the paper conveying direction.

4. The relative displacement for changing the gap between the gate of the guide member and the upstream side of the sheet conveying direction is the guide member and the gate are supported by a fulcrum provided downstream in a conveying direction of the paper; a lower end of the guide member is brought into contact with a gate stopper provided on the gate or a main body side stopper provided on a main body that holds the gate; When narrowing the gap between the gate and the guide member on the upstream side in the sheet transport direction, the guide member is brought into contact with the gate stopper, 4. The transport device according to claim 2, wherein when the gap between the gate and the guide member on the upstream side in the transport direction of the paper is widened, the guide member is brought into contact with the main body side stopper.

5. An image forming apparatus comprising the conveying device according to any one of claims 1 to 3.

Images