Conveying device and printing system

Abstract

To make it possible to eliminate double feeding without stopping conveyance, according to a conveying device and a printing system.SOLUTION: A conveying device 1 comprises: a conveyance passage R3 for conveying a medium M; a circulation passage R4 branched from a branch position P1 of the conveyance passage R3, and merging to the conveyance passage R3 at a merging position P2 on an upstream side in a conveyance direction D of the medium M rather than the branch position P1; a passage-switching mechanism 11 for switching a conveyance channel of the medium M to the conveyance passage R3 and the circulation passage R4 at the branch position P1; a double feeding detection sensor 20 arranged on the upstream side in the conveyance direction D of the medium M rather than the branch position P1 in the conveyance passage R3 to detect double feeding of the medium M; a double feeding elimination part E (conveyance rollers 37a, 39a) arranged in the circulation passage R4 to eliminate double feeding of the medium M; and a control part 91 for controlling the double feeding elimination part E so as to eliminate double feeding of media M1, M2 by controlling the passage-switching mechanism 11 so as to convey the media M1, M2 whose double feeding is detected to the circulation passage R4.SELECTED DRAWING: Figure 6E

Description

[Technical Field]

[0001] The present invention relates to a transport device and a printing system including the transport device. [Background technology]

[0002] BACKGROUND ART Conventionally, there is known an image reading device that, when a double feed is detected, sorts the double-fed paper sheets from non-double-fed paper sheets and discharges them (see, for example, Patent Document 1).

[0003] Also, a sheet material feeding device is known that includes a pair of retard rollers consisting of a feed roller that always rotates in the feeding direction and a retard roller that normally rotates in the feeding direction but rotates in the opposite feeding direction when a certain torque is applied (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-165594 [Patent Document 2] Japanese Patent Application Publication No. 05-008882 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when media such as paper sheets that have been multi-fed are sorted and discharged from media that have not been multi-fed, the task of removing the discharged media is a burden for the user, and the discharged media are wasted.

[0006] Furthermore, when the retard roller pair is used to eliminate a multi-feed during media supply, the transport of the media stops when the multi-feed is eliminated. Some printing devices employ a method of stopping transport and notifying the user when a multi-feed is detected to prevent printing defects, damage to the device due to a jam, etc. This transport stop, resulting in downtime for the device, reduces productivity.

[0007] An object of the present invention is to provide a conveying device and a printing system that can eliminate multiple feeding without stopping conveyance. [Means for solving the problem]

[0008] In one aspect, a conveying device includes a conveying path for conveying a medium, a circulation path that branches off from a branching position of the conveying path and joins the conveying path at a joining position upstream of the branching position in the conveying direction of the medium, a path switching mechanism that switches the conveying path of the medium between the conveying path and the circulation path at the branching position, a double feed detection sensor that is positioned on the conveying path upstream of the branching position in the conveying direction and detects double feed of the medium, a double feed elimination unit that is positioned on the circulation path and eliminates double feed of the medium, and a control unit that controls the path switching mechanism to convey the medium for which double feed has been detected by the double feed detection sensor to the circulation path and controls the double feed elimination unit to eliminate double feed of the medium. [Effects of the Invention]

[0009] According to this aspect, it is possible to eliminate double feeding without stopping the conveyance. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a front view showing the internal configuration of a printing system according to an embodiment. [Figure 2] FIG. 2 is a plan view showing the internal configuration of a first printing device according to an embodiment. [Figure 3] FIG. 2 is a block diagram showing a control configuration of the transport device according to the embodiment. [Figure 4A] 10 is an explanatory diagram (part 1) for explaining elimination of multi-feeds by a multi-feed elimination section according to one embodiment. FIG. [Figure 4B] FIG. 10 is a diagram (part 2) for explaining elimination of multi-feeds by the multi-feed elimination section according to one embodiment. [Figure 4C]FIG. 10 is a third explanatory diagram for explaining elimination of multifeeds by the multifeed elimination section according to an embodiment. [Figure 5] 10 is a flowchart illustrating the operation of a first printing device according to an embodiment. [Figure 6A] FIG. 1 is a first explanatory diagram for explaining the operation of the first printing device according to an embodiment. [Figure 6B] FIG. 10 is a second explanatory diagram for explaining the operation of the first printing device according to the embodiment. [Figure 6C] FIG. 10 is a third explanatory diagram for explaining the operation of the first printing device according to the embodiment. [Figure 6D] FIG. 10 is an explanatory diagram (part 4) for explaining the operation of the first printing device according to the embodiment. [Figure 6E] FIG. 5 is an explanatory diagram (part 5) for explaining the operation of the first printing device according to the embodiment. [Figure 6F] FIG. 10 is an explanatory diagram (part 6) for explaining the operation of the first printing device according to the embodiment. [Figure 6G] FIG. 10 is an explanatory diagram (part 7) for explaining the operation of the first printing device according to the embodiment. [Figure 6H] FIG. 8 is an explanatory diagram (part 8) for explaining the operation of the first printing device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] A conveying device and a printing system according to an embodiment of the present invention will be described below with reference to the drawings.

[0012] FIG. 1 is a front view showing the internal configuration of a printing system 100 according to this embodiment.

[0013] 1 and later-described Fig. 2, Fig. 4A to Fig. 4C, and Fig. 6A to Fig. 6H, the front-rear, up-down, and left-right directions are horizontal directions, and the up-down direction is vertical directions, and are perpendicular to each other. These directions are an example when the main transport direction D of the medium M (transport direction D in the transport path R3) is set to the right.

[0014] As shown in FIG. 1, the printing system 100 includes a medium supply device 110, a first printing device 120, an intermediate conveyance device 130, a second printing device 140, an inspection device 150, and a medium discharge device 160.

[0015] The medium supply device 110, first printing device 120, intermediate conveyance device 130, second printing device 140, inspection device 150, and medium discharge device 160 are arranged in series in the conveyance direction D of the medium M, in this order. In FIG. 1, the first supply path R1, second supply path R2, conveyance path R3, and first to fourth storage paths R6 to R9 for the medium M are indicated by solid lines, the circulation path R4 is indicated by a two-dot chain line, and the reverse conveyance path R4a of the circulation path R4 and a part of the reverse conveyance path of the conveyance path R3 are indicated by dashed lines. Note that the medium M is, for example, paper, but may also be a sheet-like material made of a material other than paper, or one with a folded portion such as an envelope.

[0016] The medium supply device 110 has a first supply unit 111, a second supply unit 112 arranged below the first supply unit 111, and multiple conveying roller pairs 113 that nip and convey the medium M. The first supply unit 111 and the second supply unit 112 have liftable stacking tables 111a and 112a on which the medium M is stacked, and suction conveying units 111b and 112b that suction and pay out the uppermost medium M stacked on the stacking tables 111a and 112a and convey it. A first supply path R1 for the medium M supplied from the first supply unit 111 and a second supply path R2 for the medium M supplied from the second supply unit 112 merge at a conveying path R3. Note that the medium supply device 110 may have only a single supply unit.

[0017] The first printing device 120 has a transport device 1 and a first printing unit 121, which is an example of a printing unit. The first printing unit 121 has, for example, multiple print heads arranged for each color ink: black, cyan, magenta, and yellow. Each of the multiple print heads is, for example, a line-type inkjet head extending in the main scanning direction, with multiple nozzles that eject ink arranged in the main scanning direction. The transport device 1 will be described later, but the printing system 100 including the transport device 1 and a printing unit is not limited to a printing system 100 including the first printing device 120 and the second printing device 140 (first printing unit 121 and second printing unit 142), but may also include a system including a single printing unit (for example, the first printing unit 121). In other words, the first printing device 120 itself can also be called a printing system.

[0018] The intermediate conveying device 130 has a plurality of conveying roller pairs 131 that nip and convey the medium M, and a switchback roller pair 132 that inverts the medium M. Note that the conveying path R3 in the intermediate conveying device 130 functions as a reversing conveying path.

[0019] The second printing device 140 has a plurality of pairs of conveying rollers 141 that nip and convey the medium M, a second printing unit 142 that prints on the medium M, a second printing conveying unit 143 that is arranged opposite the second printing unit 142 and conveys the medium M, and an operation panel 144 that includes a display and operation keys or a touch panel.

[0020] Similar to the first printing unit 121 of the first printing device 120, the second printing unit 142 has multiple print heads arranged for each color ink, for example, black, cyan, magenta, and yellow. Note that because the intermediate conveying device 130 turns the medium M over, the second printing unit 142 prints on the side of the medium M opposite to the printing surface printed by the first printing unit 121. However, the intermediate conveying device 130 may be provided with a transport path that does not turn the medium M over, and the second printing unit 142 may print on the same side as the first printing unit 121. In this way, when the first printing unit 121 and the second printing unit 142 share the responsibility of printing on the same side of the medium M, the second printing unit 142 may eject a different ink than the first printing unit 121. As described above, when the first printing unit 121 and the second printing unit 142 print on the same medium M (the same side or different sides), the circulation path R4 of the first printing device 120 can be used as a space for eliminating double feeds by the double feed elimination unit E, rather than being used as a transport path for double-sided printing.

[0021] The inspection device 150 includes a first inspection unit 151 , a second inspection unit 152 , a first inspection transport unit 153 , and a second inspection transport unit 154 .

[0022] The first inspection unit 151 has an imaging unit such as a CIS (Contact Image Sensor), and is disposed above the first inspection transport unit 153 so as to face the first inspection transport unit 153 in the vertical direction. The first inspection unit 151 inspects the image printed on the upper surface of the medium M.

[0023] The second inspection unit 152 is disposed downstream of the first inspection unit 151 in the conveying direction D. Like the first inspection unit 151, the second inspection unit 152 has an imaging unit such as a CIS, and is disposed below the second inspection conveying unit 154 so as to face the second inspection conveying unit 154 in the vertical direction. The second inspection unit 152 inspects the image printed on the bottom surface of the medium M.

[0024] The first inspection transport unit 153 and the second inspection transport unit 154 transport the medium M, for example, while holding the medium M by suction.

[0025] The medium discharge device 160 has an introduction section 161, a first normal storage section 162, an upper conveying section 163, an intermediate conveying section 164, a second normal storage section 165, an abnormal storage section 166, multiple pairs of conveying rollers 167, and discharge switching mechanisms 168, 169.

[0026] A plurality of pairs of conveying rollers 167 nip and convey the medium M at each section, such as the introduction section 161. A discharge switching section 168, which is, for example, a flipper, is disposed inside the introduction section 161. This discharge switching section 168 switches the conveying path R3, which runs from the medium supply device 110 through the first printing device 120, the intermediate conveying device 130, the second printing device 140, and the inspection device 150 to the introduction section 161, between a first storage path R6 leading to the first normal storage section 162 and a second storage path R7 leading to the second normal storage section 165 and the abnormal storage section 166. Although not shown, the introduction section 161 may have a reversing path that reverses the front and back of the medium M being discharged.

[0027] The first normal storage section 162 and the second normal storage section 165 have liftable stacking tables 162a, 165a on which media M are stacked. An upper transport section 163 located above the first normal storage section 162 has a second storage path R7 leading to the second normal storage section 165 and the abnormal storage section 166. A discharge switching section 169 of the upper transport section 163 is, for example, a flipper, and switches the second storage path R7 between a third storage path R8 leading to the second normal storage section 165 and a fourth storage path R9 leading to the abnormal storage section 166. An intermediate transport section 164 located between the first normal storage section 162 and the second normal storage section 165 has the third storage path R8 leading to the second normal storage section 165 and the fourth storage path R9 leading to the abnormal storage section 166 located above the second normal storage section 165.

[0028] 2, the conveying device 1 of the first printing device 120 includes a path switching mechanism 11, a discharge switching mechanism 12, a double feed detection sensor 20, conveying roller pairs 31 to 39, a switchback roller pair 41, a resupply roller pair 42, a first printing conveying unit 50, a first sensor 61, a second sensor 62, a third sensor 63, an ejection tray 70, and an operation panel 80 (see FIG. 1). Also, as shown in FIG. 3, the conveying device 1 further includes a control unit 91, a memory unit 92, an interface unit 93, and a conveying drive unit 94.

[0029] The conveyance device 1 also includes a conveyance path R3 where the first supply path R1 and the second supply path R2 join as described above, a circulation path R4 that branches off from the conveyance path R3 at a branching position P1 and joins the conveyance path R3 at a joining position P2 upstream of the branching position P1 in the conveyance direction D of the medium M, and a discharge path R5 that branches off from the circulation path R4. Here, the branching position P1 is preferably downstream of the first printing unit 121 in the conveyance direction D, and the joining position P2 is preferably upstream of the first printing unit 121 in the conveyance direction D. The conveyance path R3, the circulation path R4, and the discharge path R5 form a conveyance path for conveying the medium M by means of conveyance roller pairs 31 to 39, a switchback roller pair 41, a resupply roller pair 42, a first printing conveyance unit 50, etc., which will be described later. Although the medium M is supplied to the conveying device 1 from the above-described medium supply device 110, the medium M may also be supplied from a supply unit (e.g., an internal supply tray) arranged inside the conveying device 1 (first printing device 120). Furthermore, the conveying device 1 may be any device that conveys the medium M, and does not have to be arranged in a printing device (first printing device 120 or printing system 100). For example, the conveying device 1 may be arranged in a processing system (processing device) that performs processing other than printing, such as an inspection device.

[0030] The path switching mechanism 11 is, for example, a flipper, and switches the transport path (transport path R3) of the medium M between the transport path R3 and the circulation path R4 at the branch position P1.

[0031] The discharge switching mechanism 12 is, for example, a flipper, and switches the transport path (circulation path R4) of the medium M between the circulation path R4 and the discharge path R5.

[0032] The multi-feed detection sensor 20 is disposed on the conveying path R3 upstream of the branching position P1 in the conveying direction D. For example, the multi-feed detection sensor 20 may be disposed downstream of the merging position P2 in the conveying direction D and upstream of the first printing unit 121 in the conveying direction D. However, the multi-feed detection sensor 20 may also be disposed upstream of the merging position P2 in the conveying direction D. The multi-feed detection sensor 20 is, for example, a transmission sensor that detects multi-feeding of media M based on the amount of transmission of light irradiated onto the conveying path R3. Preferably, the multi-feed detection sensor 20 can distinguish between two sheets of media M and three or more sheets of media M that have been multi-fed. Note that multi-feeding of media M includes a state in which multiple sheets of media M completely overlap, as well as a state in which they only partially overlap in the conveying direction D.

[0033] The conveying roller pairs 31 and 32 are arranged on the conveying path R3, the conveying roller pairs 33 to 37 and 39 are arranged on the circulation path R4, the switchback roller pair 41 and the resupply roller pair 42 are arranged on the reverse conveying path R4a of the circulation path R4, and the conveying roller pair 38 is arranged on the discharge path R5. These conveying roller pairs 31 to 39, the switchback roller pair 41, and the resupply roller pair 42 convey the medium M while nipping it.

[0034] Here, one transport roller 37a of the transport roller pair 37 and one transport roller 39a of the transport roller pair 39 are drive rollers that are arranged on the circulation path R4 and function as an example of a multi-feed elimination unit E that eliminates multi-feeding of the medium M. The other transport roller of the transport roller pair 37 and the transport roller pair 39 is a driven roller. The transport roller 37a of the transport roller pair 37 is an example of a first transport member that transports the medium M on the first surface side (e.g., the lower side) of the medium M in the transport direction D (leftward in the circulation path R4) and in the opposite direction to the transport direction D (rightward in the circulation path R4). The transport roller 39a of the transport roller pair 39 is an example of a second transport member that transports the medium M in the transport direction D on the second surface side (e.g., the upper side) opposite the first surface of the medium M, downstream of the transport roller 37a (first transport member) in the transport direction D (leftward in the circulation path R4).

[0035] Here, one of the transport rollers of the transport roller pair 36, which is located upstream of the transport roller pair 37 in the transport direction D, can also transport the medium M in the opposite direction to the transport direction D (to the right in the circulation path R4), similar to the transport roller 37a of the transport roller pair 37. Therefore, one of the transport rollers of the transport roller pair 36 can also be considered a drive roller that functions as an example of a first transport member. Note that the double feed elimination unit E is not limited to the transport roller 37a (first transport member) and the transport roller 39a (second transport member) that are positioned at different positions in the transport direction D, but may also be a transport roller pair consisting of a first transport member and a second transport member that are positioned at the same position in the transport direction D. Furthermore, the first transport member and the second transport member are not limited to rollers, but may also be other transport members such as belts.

[0036] 4A, in a state where media M1 and M2, for which double feed has been detected by double feed detection sensor 20, are positioned across conveyance roller pair 37 and conveyance roller pair 39, control unit 91, which will be described later, controls double feed elimination unit E to convey conveyance roller 37a in the opposite direction to conveyance direction D (to the right in circulation path R4) and conveyance roller 39a in conveyance direction D (to the left in circulation path R4). Note that double feed elimination unit E can be considered to include an actuator that drives conveyance roller 37a and an actuator that drives conveyance roller 39a, both of which are part of conveyance drive unit 94, which will be described later.

[0037] 4B, medium M1 is conveyed in conveyance direction D by conveyance roller 39a, and medium M2 is conveyed in the opposite direction to conveyance direction D by conveyance roller 37a, whereby media M1 and M2 are separated and the double feed is resolved. The control unit 91 can determine that the double feed has been resolved in this manner based on the fact that first sensor 61 and third sensor 63 (described later) output an ON signal indicating the detected state of medium M, and that second sensor 62 outputs an OFF signal indicating the undetected state of medium M, as shown in FIG. 4C. Note that the determination that the double feed has been resolved may be made based on, for example, the first sensor 61 outputting an ON signal, the second sensor 62 outputting an OFF signal, the first sensor 61 and the third sensor 63 outputting ON signals, or the conveyance time in the opposite direction by conveyance roller 37a reaching a specified time. Therefore, the use of a total of three sensors, the first sensor 61, the second sensor 62, and the third sensor 63, is a desirable example.

[0038] Returning to FIG. 2, the switchback roller pair 41 nip and switchback-transport the medium M in the reverse transport path R4a of the circulation path R4, thereby reversing the medium M upside down.

[0039] The re-supply roller pair 42 transfers (re-supplies) the medium M, which has been turned over by the switchback roller pair 41, from the circulation path R4 to the conveyance path R3 at the joining position P2.

[0040] The first print transport unit 50 is disposed opposite the first print unit 121 and transports the medium M. The first print transport unit 50 includes a belt 51, a plurality of pulleys 52 to 54 around which the belt 51 is stretched, a guide roller 55 disposed opposite the pulley 52 at the upstream end of the first print transport unit 50 in the transport direction D, and a guide roller 56 disposed opposite the pulley 53 at the downstream end of the first print transport unit 50 in the transport direction D. The first print transport unit 50 may further include a suction fan that sucks air through suction holes provided in the belt 51 to adsorb the medium M to the belt 51.

[0041] The first sensor 61, the second sensor 62, and the third sensor 63 are arranged on the circulation path R4 (the third sensor 63 is on the reverse conveying path R4a of the circulation path R4) and detect the presence or absence of the medium M. The first sensor 61 is arranged upstream of the conveying roller 37a in the conveying direction D (between the conveying roller pair 35 and the conveying roller pair 36). The second sensor 62 is arranged downstream of the conveying roller 37a in the conveying direction D and upstream of the conveying roller 39a in the conveying direction D. The third sensor 63 is arranged downstream of the conveying roller 39a in the conveying direction D (on the reverse conveying path R4a). For example, the first sensor 61, the second sensor 62, and the third sensor 63 are reflective sensors that detect the presence or absence of the medium M based on the reflected light of light irradiated onto the circulation path R4.

[0042] The discharge tray 70 is connected to the discharge path R5, and is loaded with the medium M conveyed by the conveyance roller pair 38 arranged on the discharge path R5.

[0043] The operation panel 80 shown in FIG. 1 has a display that displays various information, and operation keys or a touch panel that accepts information input by the user.

[0044] The control unit 91 shown in FIG. 3 has, for example, one or more processors (e.g., CPU: Central Processing Unit) that function as an arithmetic processing device that controls the operation of each unit of the conveying device 1. This processor reads and executes a predetermined program, for example, from the memory unit 92 or from a storage medium (non-transitory computer-readable recording medium) that is detachable from the conveying device 1. In this way, the control unit 91 functions as an example of a computer that executes a program. Note that the control unit 91 and the memory unit 92 may be the control unit and memory unit of the first printing device 120 or the printing system 100. In the example described below, an example will be described in which the control unit 91 also controls the first printing unit 121, that is, the control unit of the first printing device 120.

[0045] The storage unit 92 includes, for example, a memory such as a ROM (Read Only Memory), which is a read-only semiconductor memory in which a predetermined control program is pre-recorded, a RAM (Random Access Memory), which is a semiconductor memory that can be written and read at any time and is used as a working memory area as needed when the processor executes various control programs, or a hard disk device.

[0046] The interface unit 93 exchanges various types of information with other devices in the printing system 100 and external devices such as a print control device that controls the printing system 100 .

[0047] The transport drive unit 94 has a plurality of actuators such as a path switching mechanism 11, a discharge switching mechanism 12, transport roller pairs 31 to 39, a switchback roller pair 41, a resupply roller pair 42, and a motor for driving the first print transport unit 50.

[0048] FIG. 5 is a flowchart for explaining the operation of the first printing apparatus 120 (transportation apparatus 1).

[0049] 6A to 6H are explanatory diagrams for explaining the operation of the first printing device 120 (transportation device 1).

[0050] First, the control unit 91 receives a print start instruction from the first printing device 120 and causes the transport drive unit 94 to start transporting the medium M, and then determines for each medium M whether a multi-feed has been detected by the multi-feed detection sensor 20 (step S1).

[0051] If the multi-feed detection sensor 20 does not detect multi-feeding of the medium M (step S1: NO), the control unit 91 controls the first printing unit 121 to print on the medium M (step S2), and the processing shown in Figure 5 ends.

[0052] In this way, while no double feeding of medium M is detected, as shown in Figure 6A, medium M is continuously transported to the first printing unit 121, and medium M printed by the first printing unit 121 is transported by the transport roller pair 32 to the intermediate transport device 130 shown in Figure 1.

[0053] 6B, when the multi-feed detection sensor 20 detects a multi-feed of media M (M1, M2) (step S1: YES) and outputs an ON signal indicating a multi-feed, the control unit 91 determines whether the multi-feed is three or more sheets or whether the multi-feed is continuous (step S3). Whether the multi-feed is three or more sheets may be determined based on the amount of light transmitted through the multi-feed detection sensor 20. Note that if a single medium M without a multi-feed is transported after the multi-feed of media M, and then another medium M with a multi-feed is transported, the next medium M with a multi-feed will be transported to the circulation path R4 before the multi-feed is resolved in the circulation path R4. Therefore, whether the multi-feed is continuous may be determined based on whether a new multi-feed is detected before the previous multi-feed is resolved.

[0054] If there are three or more sheets of paper that have been multi-fed or if multi-fed sheets have continued (step S3: YES), the control unit 91 stops the operation of the first printing device 120 (step S4), and the processing shown in Fig. 5 ends. Note that when the operation of the first printing device 120 is stopped, it is also necessary to stop the supply of media M by the medium supply device 110. Therefore, the control unit 91 may transmit information indicating that the operation of the first printing device 120 has stopped to the medium supply device 110 or the printing control device that controls this medium supply device 110. The user may then be notified by display or sound that the operation of the first printing device 120 (printing system 100) has stopped.

[0055] If there are two sheets of overlapping paper and the overlapping paper is not continuous (step S3: NO), the control unit 91 controls the path switching mechanism 11 to not print on the overlapping paper media M1 and M2 and to switch the transport path to the circulation path R4 (step S5), as shown in Fig. 6C. Note that if the overlapping paper media M1 and M2 are completely overlapping, printing may be performed only on the medium M2, and after the overlapping paper media M1 is resolved on the circulation path R4, printing may be performed only on the medium M1; however, it is preferable not to print while the overlapping paper media M1 is in a state where the overlapping paper media M1 and M2 are overlapping.

[0056] As shown in Figure 6D, if no double feed has occurred, printing is performed on the medium M that is transported next after the media M1 and M2 in which double feed has occurred, and the medium M is transported to the intermediate transport device 130 shown in Figure 1 by the transport roller pair 32.

[0057] As shown in Figure 6E, the control unit 91 determines that the media M1 and M2 that have experienced double feeding have been transported to a state where they are positioned between the transport roller 37a (first transport member) of the transport roller pair 37 and the transport roller 39a (second transport member) of the transport roller pair 39, based on, for example, the fact that a specified time corresponding to the transport speed has elapsed since the second sensor 62 output an ON signal.

[0058] Then, as shown in Figure 6F, the control unit 91 eliminates the double feed by controlling the conveying drive unit 94 to convey medium M1 in conveying direction D (leftward in circulation path R4) by conveying roller 39a and convey medium M2 in the opposite direction of conveying direction D (rightward in circulation path R4) by conveying roller 37a (step S6).

[0059] Then, the control unit 91 determines whether it can be determined that the multi-feed has been resolved by the first sensor 61 and the third sensor 63 outputting an ON signal and the second sensor 62 outputting an OFF signal, as shown in Fig. 6G (step S7). Note that if there is a possibility that the multi-feed of the media M1 and M2 detected as a multi-feed by the multi-feed detection sensor 20 will be resolved during the transport process, a multi-feed resolution determination process (step S7) may be performed before the multi-feed resolution process (step S6).

[0060] If the control unit 91 cannot determine that the multifeed has been resolved (step S7: NO), it repeats the process from the multifeed resolution process (step S6) described above.

[0061] On the other hand, if the control unit 91 determines that the double feed has been resolved (step S7: YES), as shown in Figure 6H, it causes the two media M1 and M2, whose double feed has been resolved, to be transported sequentially in the transport direction D by the transport rollers 37a, 39a, etc. (step S8).

[0062] Then, when the control unit 91 transfers (supplies) the two media M1 and M2, for which the double feed has been resolved, from the circulation path R4 to the conveying path R3, it temporarily suspends the conveying of the media M located upstream of the merging position P2 of the circulation path R4 (for example, for two sheets of media M1 and M2) (step S9). Note that because the timing at which the two media M1 and M2 are conveyed from the circulation path R4 to the conveying path R3 can be calculated after determining that the double feed has been resolved in step S7 described above, the supply of media M from the medium supply device 110 may be halted for two sheets. Furthermore, media M1 and media M2 may be supplied from the circulation path R4 to the conveying path R3 so that a new medium M is conveyed between media M1 and M2.

[0063] Then, the control unit 91 controls the first printing unit 121 to print on the two media M1 and M2 on the conveyance path R3 for which the double feeding has been resolved (step S2), and the process shown in FIG. 5 ends.

[0064] In the present embodiment described above, the conveying device 1 includes a conveying path R3 for conveying the medium M, a circulation path R4 that branches off from the conveying path R3 at a branching position P1 and joins the conveying path R3 at a joining position P2 upstream of the branching position P1 in the conveying direction D of the medium M, a path switching mechanism 11 that switches the conveying path of the medium M between the conveying path R3 and the circulation path R4 at the branching position P1, a double feed detection sensor 20 that is arranged on the conveying path R3 upstream of the branching position P1 in the conveying direction D and detects double feed of the medium M, a double feed elimination unit E (conveying rollers 37a, 39a) that is arranged on the circulation path R4 and eliminates double feed of the medium M, and a control unit 91 that controls the path switching mechanism 11 to convey the media M1, M2 for which double feed has been detected to the circulation path R4, and controls the double feed elimination unit E to eliminate double feed of the media M1, M2.

[0065] In this way, by using the multi-feed elimination unit E to eliminate the multi-feed of the detected media M1, M2, it is possible to omit the user's work of removing the ejected media M1, M2 and to reuse the media M1, M2, compared to, for example, a mode in which the detected multi-feed media M1, M2 are sorted and ejected. Also, because the multi-feed elimination unit E eliminates the multi-feed on the circulation path R4, it is possible to continue transporting the media M for which no multi-feed has occurred on the transport path R3, thereby avoiding stopping the transport of the media M. Therefore, according to this embodiment, it is possible to eliminate the multi-feed without stopping the transport.

[0066] Furthermore, in the present embodiment, the multi-feed elimination unit E includes a transport roller 37a, which is an example of a first transport member, and a transport roller 39a, which is an example of a second transport member. The transport roller 37a transports the medium M on the first surface side of the medium M in the transport direction D and in the direction opposite to the transport direction D. The transport roller 39a transports the medium M in the transport direction D on the second surface side opposite the first surface of the medium M, downstream of the transport roller 37a in the transport direction D. The control unit 91 controls the multi-feed elimination unit E to transport the media M1 and M2, for which multi-feeding has been detected by the multi-feed detection sensor 20, in the opposite direction by the transport roller 37a, and to transport the media M1 and M2 in the transport direction D by the transport roller 39a.

[0067] This makes it possible to reliably prevent double feeding of the media M1 and M2 on the circulation path R4 with a simple configuration.

[0068] Furthermore, in this embodiment, the conveying device 1 further includes a first sensor 61, a second sensor 62, and a third sensor 63 that are disposed on the circulation path R4 and detect the presence or absence of the medium M. The first sensor 61 is disposed upstream of the conveying roller 37a in the conveying direction D. The second sensor 62 is disposed downstream of the conveying roller 37a in the conveying direction D and upstream of the conveying roller 39a in the conveying direction D. The third sensor 63 is disposed downstream of the conveying roller 39a in the conveying direction D. The control unit 91 determines whether the multi-feed elimination unit E has eliminated the multi-feed based on the detection results of the first sensor 61, the second sensor 62, and the third sensor 63.

[0069] This allows the control unit 91 to reliably determine whether the multiple feeding has been resolved.

[0070] In addition, in this embodiment, when the control unit 91 determines that the double feed of media M1 and M2 has been resolved by the double feed resolution unit E, the control unit 91 causes the two media M1 and M2 whose double feed has been resolved to be transported sequentially in the transport direction D by the transport rollers 37a and 39a.

[0071] This allows the media M1 and M2, whose double feeding has been resolved, to be supplied to the transport path R3, thereby eliminating the need for the user to remove the media M1 and M2 and allowing the media M1 and M2 to be reused.

[0072] Furthermore, in this embodiment, the printing system 100 includes the conveying device 1 and a first printing unit 121, which is an example of a printing unit that prints on the medium M. The first printing unit 121 is disposed on the conveying path R3 upstream of the branching position P1 in the conveying direction D and downstream of the merging position P2 and the double feed detection sensor 20 in the conveying direction D, and the control unit 91 controls the first printing unit 121 and the path switching mechanism 11 to convey the media M1, M2 for which double feed has been detected by the double feed detection sensor 20 to the circulation path R4 without printing, and controls the first printing unit 121 to print on the two media M1, M2 for which double feed has been resolved by the double feed elimination unit E of the circulation path R4.

[0073] As a result, the media M1 and M2 whose double feed has been resolved on the circulation path R4 can be supplied to the transport path R3, and printing can be performed on each of the media M1 and M2 in a state where the double feed has been resolved.

[0074] The present invention is not limited to the above-described embodiments, and the components can be modified and embodied without departing from the spirit of the invention. Furthermore, various inventions can be formed by appropriately combining the multiple components disclosed in the above-described embodiments. For example, all of the components shown in the embodiments can be appropriately combined. Naturally, various modifications and applications are possible without departing from the spirit of the invention. The invention as originally claimed in the present application is described below.

[0075] [Appendix 1] a transport path for transporting the medium; a circulation path that branches off from a branching position of the transport path and merges with the transport path at a merging position that is upstream of the branching position in the transport direction of the medium; a path switching mechanism that switches the transport path of the medium between the transport path and the circulation path at the branch position; a double feed detection sensor disposed on the conveying path upstream of the branching position in the conveying direction, the double feed detection sensor detecting double feed of the media; a multi-feed elimination unit disposed in the circulation path and configured to eliminate multi-feeding of the media; a control unit that controls the path switching mechanism to transport the medium in which a double feed has been detected by the double feed detection sensor to the circulation path, and controls the double feed elimination unit to eliminate the double feed of the medium; A conveying device comprising:

[0076] [Appendix 2] the double feed elimination unit includes a first transport member that transports the medium in the transport direction and a direction opposite to the transport direction on a first surface side of the medium, and a second transport member that transports the medium in the transport direction on a second surface side opposite the first surface of the medium downstream of the first transport member in the transport direction, The control unit controls the multi-feed elimination unit to cause the first transport member to transport the medium in the opposite direction and the second transport member to transport the medium in the transport direction, the medium being detected as being multi-feeded by the multi-feed detection sensor. 2. The conveying device according to claim 1.

[0077] [Appendix 3] a first sensor, a second sensor, and a third sensor disposed in the circulation path and configured to detect the presence or absence of the medium; the first sensor is disposed upstream of the first conveying member in the conveying direction, the second sensor is disposed downstream of the first conveying member in the conveying direction and upstream of the second conveying member in the conveying direction, the third sensor is disposed downstream of the second conveying member in the conveying direction, The control unit determines whether the multifeed has been resolved by the multifeed resolution unit based on detection results of the first sensor, the second sensor, and the third sensor. 3. The conveying device according to claim 2.

[0078] [Appendix 4] When the multifeed eliminating section determines that the multifeed of the media has been eliminated, the control section causes the first conveying member and the second conveying member to sequentially convey the two media whose multifeed has been eliminated in the conveying direction. 4. The conveying device according to claim 2 or 3.

[0079] [Appendix 5] A conveying device according to any one of Supplementary Notes 1 to 4; a printing unit that prints on the medium; A printing system comprising: the printing unit is disposed on the conveying path upstream of the branching position in the conveying direction and downstream of the joining position and the double feed detection sensor in the conveying direction; The control unit controls the printing unit and the path switching mechanism to transport the medium for which a double feed has been detected by the double feed detection sensor to the circulation path without printing, and controls the printing unit to print on two of the media for which a double feed has been resolved by the double feed resolution unit on the circulation path. A printing system characterized by: [Explanation of symbols]

[0080] 1. Conveyor device 11 Route switching mechanism 12 Emission switching mechanism 20 Double feed detection sensor 31~39 Conveyor roller pairs 37a Conveying roller (first conveying member) 39a Conveying roller (second conveying member) 41 Switchback roller pair 42 Resupply roller pair 50 First printing transport unit 51 Belt 52, 53, 54 Pulleys 55,56 Guide roller 61 First Sensor 62 Second Sensor 63 Third Sensor 70 Output tray 80 Operation Panel 91 Control Unit 92 Memory section 93 Interface section 94 Conveyor drive unit 100 Printing Systems 110 Media supply device 111 1st supply section 111a Loading Platform 111b Suction conveyance section 112 2nd supply section 112a Loading platform 112b suction transport section 113 conveying roller pair 120 1st printing device 121 1st Printing Department 130 Intermediate conveying device 131 conveying roller pair 132 Switchback Roller Pair 140 2nd printing device 141 conveying roller pair 142 2nd Printing Department 143 Second printing transport unit 144 Operation Panel 150 Inspection equipment 151 First Inspection Department 152 Second Inspection Department 153 First Inspection and Transport Department 154 Second Inspection and Transport Department 160 Media ejector 161 Introduction 162 First normal storage area 162a Loading platform 163 Upper conveying section 164 Intermediate conveying section 165 Second normal storage area 166 Abnormal Storage Unit 167 Conveyor roller pair 168,169 Emission switching mechanism D Conveying direction E. Double feed prevention unit M medium P1 Branch position P2 merging position R1 1st supply path R2 2nd supply path R3 transport path R4 circulation path R4a Reversing transport path R5 discharge path R6 1st storage path R7 2nd access road R8 3rd access road R9 4th access road

Claims

1. a transport path for transporting the medium; a circulation path that branches off from a branching position of the conveying path and merges with the conveying path at a merging position that is upstream of the branching position in the conveying direction of the medium; a path switching mechanism that switches the transport path of the medium between the transport path and the circulation path at the branch position; a double feed detection sensor disposed on the conveying path upstream of the branching position in the conveying direction, the double feed detection sensor detecting double feed of the media; a multi-feed elimination unit disposed in the circulation path and configured to eliminate multi-feeding of the media; a control unit that controls the path switching mechanism to transport the medium in which a double feed has been detected by the double feed detection sensor to the circulation path, and controls the double feed elimination unit to eliminate the double feed of the medium; A conveying device comprising:

2. the double feed elimination unit includes a first transport member that transports the medium in the transport direction and in a direction opposite to the transport direction on a first surface side of the medium, and a second transport member that transports the medium in the transport direction on a second surface side opposite the first surface of the medium downstream of the first transport member in the transport direction, The control unit controls the multi-feed elimination unit to cause the first transport member to transport the medium in the opposite direction and the second transport member to transport the medium in the transport direction, the medium being detected as being multi-feeded by the multi-feed detection sensor.

2. The conveying device according to claim 1.

3. The device further includes a first sensor, a second sensor, and a third sensor disposed in the circulation path and configured to detect the presence or absence of the medium; the first sensor is disposed upstream of the first conveying member in the conveying direction, the second sensor is disposed downstream of the first conveying member in the conveying direction and upstream of the second conveying member in the conveying direction, the third sensor is disposed downstream of the second conveying member in the conveying direction, The control unit determines whether the multifeed has been resolved by the multifeed resolution unit based on the detection results of the first sensor, the second sensor, and the third sensor.

3. The conveying device according to claim 2.

4. When the multifeed eliminating section determines that the multifeed of the media has been eliminated, the control section causes the first conveying member and the second conveying member to sequentially convey the two media whose multifeed has been eliminated in the conveying direction.

3. The conveying device according to claim 2.

5. A conveying device according to any one of claims 1 to 4; a printing unit that prints on the medium; A printing system comprising: the printing unit is disposed on the conveying path upstream of the branching position in the conveying direction and downstream of the joining position and the double feed detection sensor in the conveying direction; The control unit controls the printing unit and the path switching mechanism to transport the medium for which a multi-feed has been detected by the multi-feed detection sensor to the circulation path without printing, and controls the printing unit to print on two of the media for which a multi-feed has been resolved by the multi-feed resolution unit on the circulation path. A printing system characterized by:

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