Media Supply Agency

Abstract

To provide a medium supply mechanism capable of inhibiting variation, due to variety of media, in arrival time of the media conveyed on transport paths having curved portions.SOLUTION: A medium supply mechanism comprises: a first supply unit 11 and a second supply unit 12 being an example of supply unit for supplying media M; a first individual conveyance path P1, a second individual conveyance path P2 and a merging conveyance path P3 being an example of conveyance paths being connected with the first supply unit 11 and a second supply unit 12 and having curved portions (first to fourth curved portions C1 to C4); pairs of first to ninth conveyance rollers 21 to 29 and a pair of receiving rollers 132 being an example of conveyance units for conveying the media M thereon; and a control unit 31 for controlling the first to ninth conveyance roller pairs 21 to 29. The control unit 31 adjusts conveyance speeds of the media M conveyed by the first to ninth conveyance roller pairs 21 to 29 on the basis of a thickness being an example of media information of the media M and shapes of the conveyance paths of the media M.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a media supply mechanism. [Background technology]

[0002] Conventionally, in a media supplying device that supplies media such as paper to a destination device such as a printing device, the conveying speed may be adjusted so that the arrival timing (arrival time) of the media at the destination device matches a reference arrival timing (reference arrival time), which is a theoretical value.

[0003] For example, in an image forming device, a method has been proposed in which the arrival time from when paper feeding begins to when it is detected by a paper detection sensor is measured, and the paper transport speed from downstream of the paper detection sensor to when it reaches a registration roller is changed based on this measured arrival time (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-298168 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, when a medium transport path has a curved portion, the position where the medium passes through the curved portion differs depending on the stiffness of the medium. As a result, differences occur in the path length that the medium actually passes through. For example, a stiff medium such as thick paper will try to pass through the shortest path in the curved portion, resulting in a shorter path length, or a weak medium such as thin paper will try to pass along the guide plate on the outside of the curved portion, resulting in a longer path length.

[0006] Therefore, when the transport path has a curved portion, the timing (arrival time) of the medium to reach the destination device, such as a printing device, varies depending on the type of medium. For example, in a printing device that corrects skew of the medium by abutting the medium against a pair of registration rollers, the timing of the medium abutting the pair of registration rollers varies depending on the type of medium. This causes variations in the ability to correct skew of the medium, resulting in a decrease in image quality in the printed result or the occurrence of a jam.

[0007] As described above, by measuring the arrival time until detection by the paper detection sensor and changing the paper transport speed from downstream of the paper detection sensor until it reaches the registration roller, the arrival timing of the media at the destination device can be made closer to constant, but it is not possible to suppress fluctuations in the arrival timing depending on the type of media.

[0008] An object of the present invention is to provide a medium supply mechanism that can suppress variations in arrival time due to the type of medium transported in a transport path that has a curved portion. [Means for solving the problem]

[0009] In one aspect, the medium supply mechanism includes a supply unit that supplies medium, a transport path connected to the supply unit and having a curved portion, a transport unit that transports the medium on the transport path, and a control unit that controls the transport unit, and the control unit adjusts the transport speed of the medium by the transport unit based on media information of the medium and the transport path shape of the medium. Effect of the Invention

[0010] According to this aspect, it is possible to suppress variation in arrival time due to the type of medium transported in a transport path having a curved portion. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating an internal configuration of a printing system according to an embodiment. [Diagram 2]FIG. 2 is a diagram illustrating a control configuration of a medium supplying device and a printing device according to an embodiment. [Diagram 3] 1A is an explanatory diagram for explaining the positions where thick and thin paper pass through in a curved portion (large corner angle), in a curved portion (medium corner angle), and in a curved portion (small corner angle), respectively. FIG. [Figure 4] FIG. 11 is a diagram (part 1) showing the relationship between the medium transport speed and elapsed time in the medium supply mechanism according to the embodiment. [Diagram 5] FIG. 2 is a second diagram showing the relationship between the medium transport speed and elapsed time in the medium supply mechanism according to the embodiment. [Figure 6] FIG. 11 is a third diagram showing the relationship between the medium transport speed and elapsed time in the medium supply mechanism according to the embodiment. [Figure 7] 13 is a diagram showing the relationship between the medium transport speed and elapsed time in the medium supply mechanism of Comparative Example 1. FIG. [Figure 8] 13 is a diagram showing the relationship between the medium transport speed and elapsed time in the medium supply mechanism of Comparative Example 2. FIG. [Figure 9] 13 is a diagram showing transport times of a medium supplied from a first supply unit (thick line) and a second supply unit (thin line) in another embodiment (first supply unit v0=second supply unit v0). [Figure 10] 13 is a diagram showing the transport time of a medium supplied from a first supply section (thick line) and a second supply section (thin line) in Comparative Example 3 (first supply section v0=second supply section v0, medium: thin). [Figure 11] 13 is a diagram showing the transport time of a medium supplied from a first supply section (thick line) and a second supply section (thin line) in Comparative Example 4 (first supply section v0=second supply section v0, medium: thick). [Figure 12] 13 is a diagram showing transport times of a medium supplied from a first supply unit (thick line) and a second supply unit (thin line) in another embodiment (first supply unit v0>second supply unit v0). [Figure 13] 13 is a diagram showing the transport time of a medium supplied from a first supply section (thick line) and a second supply section (thin line) in Comparative Example 5 (first supply section v0>second supply section v0, medium: thin). [Figure 14] 13 is a diagram showing the transport time of the medium supplied from the first supply section (thick line) and the second supply section (thin line) in Comparative Example 6 (first supply section v0>second supply section v0, medium: thickness). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A medium supply mechanism according to an embodiment of the present invention will now be described with reference to the drawings.

[0013] <One embodiment> FIG. 1 is a diagram showing the internal configuration of a printing system 100. As shown in FIG.

[0014] FIG. 2 is a diagram showing the control configuration of the medium supplying device 1 and the printing device 101.

[0015] Note that the front-rear, up-down, and left-right directions shown in FIG. 1 are merely directions for convenience of explanation, but for example, the front-rear and left-right directions are horizontal directions, and the up-down direction is vertical directions.

[0016] 1 includes a medium supplying device 1 and a printing device 101. Although described in detail later, the medium supplying mechanism in this embodiment includes the medium supplying device 1 and a conveying path configuration up to a registration roller pair 131 of the printing device 101 (receiving roller pair 132, registration sensor S10, and junction conveying path P3).

[0017] The medium supplying device 1 supplies the medium M to a printing device 101, which is an example of a supply destination device of the medium M. The supply destination device may be other devices such as a conveying device or a post-processing device. The medium supplying device 1 may be provided integrally with a supply destination device such as the printing device 101. The medium M is, for example, paper (sheets), but may also be other sheet-like media such as film.

[0018] 1, the medium supplying device 1 includes a first supplying section 11, a second supplying section 12, a first individual transport path P1, a second individual transport path P2, a junction transport path P3, first to ninth transport roller pairs 21 to 29, first to fourth transport driving sections D1 to D4, a first inlet passage detection sensor S1, a first outlet passage detection sensor S2, a second inlet passage detection sensor S3, and a second outlet passage detection sensor S4. Also, as shown in FIG. 2, the medium supplying device 1 includes a control section 31, a storage section 32, and an interface section 33.

[0019] The medium supply device 1 is divided into an upper stage 1a and a lower stage 1b, with the first supply unit 11 disposed in the upper stage 1a and the second supply unit 12 disposed in the lower stage 1b. In this manner, the first supply unit 11 and the second supply unit 12 are disposed side by side vertically. The first supply unit 11 and the second supply unit 12 are an example of a supply unit that supplies the medium M. As this supply unit, a single supply unit or three or more supply units may be disposed. Furthermore, the direction in which the multiple supply units are disposed may be the front-rear direction or the left-right direction, and is not particularly limited.

[0020] The first supply unit 11 and the second supply unit 12 each include a loading platform 11a, a suction transport unit 11b, and a medium thickness setting unit 11c.

[0021] A plurality of media M are loaded on the loading stages 11a and 12a.

[0022] The suction conveying units 11b and 12b have, for example, two pulleys and a belt stretched around these pulleys, and feed the medium M that is attracted to the belt by, for example, air suction, one by one. The suction conveying units 11b and 12b are an example of a feed unit that feeds the medium M from the first supply unit 11 and the second supply unit 12 one by one.

[0023] The medium thickness setting units 11c and 12c are set by the user to the thickness of the medium M loaded on the loading tables 11a and 12a. For example, the medium thickness setting units 11c and 12c have a lever or dial that can be moved to a position marked "cardboard" indicating that the medium M is cardboard, a position marked "plain paper" indicating that the medium M is plain paper, and a position marked "thin paper" indicating that the medium M is thin paper. The control unit 31, which will be described later, acquires the thickness of the medium M, which is an example of medium information set in the medium thickness setting units 11c and 12c. The medium information may be information such as the material of the medium M. The control unit 31 may also acquire medium information such as the thickness of the medium M set in a print job, an operation panel of the printing device 101, or the like.

[0024] Although not shown in the figure, the first supply unit 11 and the second supply unit 12 each have a loading platform lifting drive unit such as a motor (an example of an actuator) that moves the loading platforms 11a, 12a up and down, and a payout drive unit such as a motor (an example of an actuator) that rotates a drive pulley, which is one of the two pulleys of the suction conveying units 11b, 12b.

[0025] In addition, the first supply section 11 and the second supply section 12 may be provided with a floating air blowing mechanism that blows floating air to float multiple media M including the topmost medium M stacked on the loading tables 11a, 12a, and a separation air blowing mechanism that blows separation air to separate the topmost medium M from the lower media M.

[0026] The first individual conveying path P1 is connected to the first supply unit 11. The second individual conveying path P2 is connected to the second supply unit 12. The junction conveying path P3 is a conveying path where the first individual conveying path P1 and the second individual conveying path P2 join together, and extends to the registration roller pair 131 of the printing device 101. The first individual conveying path P1 and the second individual conveying path P2 are examples of multiple individual conveying paths connected to the multiple supply units (the first supply unit 11 and the second supply unit 12), respectively.

[0027] Most of the first individual transport path P1 is disposed in the upper stage 1a of the medium supplying device 1, and the second individual transport path P2 is disposed in the lower stage 1b of the medium supplying device 1. The first individual transport path P1 merges with the second individual transport path P2 at the junction transport path P3 disposed in the lower stage 1b. In this manner, the transport paths of the medium supplying device 1 include the first individual transport path P1, the second individual transport path P2, and a part of the junction transport path P3. Note that the first individual transport path P1 is longer in the transport direction of the medium M than the second individual transport path P2.

[0028] The medium M supplied from the first supply unit 11 is transported on the first individual transport path P1 and the junction transport path P3, so the transport path of the medium M supplied from the first supply unit 11 is the first individual transport path P1 and the junction transport path P3. The medium M supplied from the second supply unit 12 is transported on the second individual transport path P2 and the junction transport path P3, so the transport path of the medium M supplied from the second supply unit 12 is the second individual transport path P2 and the junction transport path P3.

[0029] The first individual conveying path P1 is provided between the first conveying roller pair 21 and the second conveying roller pair 22, and has a first curved portion C1 that curves downward from the right in the conveying direction, and a second curved portion C2 that is provided between the fifth conveying roller pair 25 and the eighth conveying roller pair 28, and curves downward from the bottom to the lower right in the conveying direction.

[0030] The second individual transport path P2 is provided between the seventh transport roller pair 27 and the eighth transport roller pair 28, and has a third curved portion C3 that curves from the right direction to the lower right direction in the transport direction.

[0031] The junction conveying path P3 is provided between the ninth conveying roller pair 29 and the registration roller pair 131 between the medium supplying device 1 and the printing device 101, and has a fourth curved portion C4 that curves from the lower right to the upper right in the conveying direction.

[0032] Here, since the transport path for the medium M has the above-mentioned first to fourth curved portions C1 to C4, when the medium M passes through the first to fourth curved portions C1 to C4, the position through which the medium M passes varies depending on the stiffness of the medium M. Therefore, a difference occurs in the length of the path through which the medium M actually passes.

[0033] For example, as shown in FIG. 3(a), in the first curved portion C1 (large corner angle) that curves from the right to the downward direction in the conveying direction at, for example, about 90 degrees, between the first conveying roller pair 21 and the second conveying roller pair 22, the stiff thick paper Ma shown by the thick dashed line attempts to pass through the shortest path, resulting in a shorter path length, while the weak thin paper Mb shown by the thin dashed line attempts to pass along the outer guide plate, resulting in a longer path length.

[0034] In addition, in the curved portion C1-1 (medium corner angle) in which the first curved portion C1 is changed to be curved from the right to the lower right in the conveying direction at, for example, about 45 degrees as shown in Figure 3 (b), although the difference in path length is smaller than that of the first curved portion C1, a difference in path length occurs between the thick paper Ma, which has a long path length, and the thin paper Mb, which has a short path length.

[0035] As shown in Figure 3 (c), in the third curved portion C3 (small corner angle) that curves from the right to the lower right at an angle of, for example, about 30 degrees in the conveying direction, the difference in path length is smaller than that between the first curved portion C1 and the curved portion C1-1, but a difference in path length occurs between the seventh conveying roller pair 27 and the eighth conveying roller pair 28 between the thick paper Ma, which has a long path length, and the thin paper Mb, which has a short path length.

[0036] As described above, the path length of the medium M varies depending on the thickness (rigidity) of the curved portions (first to third curved portions C1 to C3). Therefore, the path length of the medium M, and therefore the arrival timing at the registration roller pair 131, varies depending on the thickness of the medium M and the shape of the transport path in the medium transport path (for example, the size and presence or absence of corner angles of the first to fourth curved portions C1 to C4).

[0037] Each of the first to ninth transport roller pairs 21 to 29 has a drive roller and a driven roller disposed opposite each other, and transports the medium M while nipping it.

[0038] The first to fifth conveying roller pairs 21-25 convey the medium M in the first individual conveying path P1 in the upper stage 1a of the medium supplying device 1. The sixth and seventh conveying roller pairs 26, 27 convey the medium M in the second individual conveying path P2 in the lower stage 1b of the medium supplying device 1. The eighth and ninth conveying roller pairs 28, 29 convey the medium M in the merging conveying path P3 in the lower stage 1b of the medium supplying device 1. The first to fifth conveying roller pairs 21-25 and the sixth and seventh conveying roller pairs 26, 27 are an example of a plurality of individual conveying sections that convey the medium M in the first individual conveying path P1 and the second individual conveying path P2 (a plurality of individual conveying paths). The eighth and ninth conveying roller pairs 28, 29 and a receiving roller pair 132 of the printing device 101 described later are an example of a merging conveying section that conveys the medium M in the merging conveying path P3. That is, the medium supply mechanism is equipped with a transport section that transports the medium M, and has a plurality of individual transport sections (first to fifth transport roller pairs 21 to 25 and sixth and seventh transport roller pairs 26, 27) and a merging transport section (eighth and ninth transport roller pairs 28, 29 and a receiving roller pair 132).

[0039] The first to fourth transport drive units D1 to D4 are motors (one example of actuators) that rotate the drive rollers of the first to ninth transport roller pairs 21 to 29. The first transport drive unit D1 rotates the drive rollers of the first and second transport roller pairs 21, 22. The second transport drive unit D2 rotates the drive rollers of the third to fifth transport roller pairs 23 to 25. The third transport drive unit D3 rotates the drive rollers of the sixth and seventh transport roller pairs 26, 27. The fourth transport drive unit D4 rotates the drive rollers of the eighth and ninth transport roller pairs 28, 29. The first and second transport drive units D1, D2 and the third transport drive unit D3 are one example of individual transport drive units that drive a plurality of individual transport units (the first to fifth transport roller pairs 21 to 25 and the sixth and seventh transport roller pairs 26, 27). The conveyance drive unit (not shown) that drives the fourth conveyance drive unit D4 and the receiving roller pair 132 is an example of a junction conveyance drive unit that drives the junction conveyance unit (the eighth and ninth conveyance roller pairs 28, 29 and the receiving roller pair 132). That is, the medium supply mechanism includes a conveyance drive unit having individual conveyance drive units (the first to third conveyance drive units D1 to D3) and a junction conveyance drive unit (the conveyance drive unit of the fourth conveyance drive unit D4 and the receiving roller pair 132).

[0040] The first entrance passage detection sensor S1, the first exit passage detection sensor S2, the second entrance passage detection sensor S3, and the second exit passage detection sensor S4 are, for example, reflective or transmissive photoelectric sensors that detect the passage of the media M.

[0041] The first inlet passage detection sensor S1 is disposed adjacent to the first conveying roller pair 21 on the downstream side in the conveying direction of the first conveying roller pair 21. The first outlet passage detection sensor S2 is disposed adjacent to the fifth conveying roller pair 25 on the downstream side in the conveying direction of the fifth conveying roller pair 25. As a result, the first inlet passage detection sensor S1 detects the passage of the medium M near the inlet of the first individual conveying path P1, and the first outlet passage detection sensor S2 detects the passage of the medium M near the exit of the first individual conveying path P1.

[0042] The second inlet passage detection sensor S3 is disposed adjacent to the sixth conveying roller pair 26 on the downstream side in the conveying direction of the sixth conveying roller pair 26. The second outlet passage detection sensor S4 is disposed adjacent to the ninth conveying roller pair 29 on the downstream side in the conveying direction of the ninth conveying roller pair 29. As a result, the second inlet passage detection sensor S3 detects the passage of the medium M near the inlet of the second individual conveying path P2, and the second outlet passage detection sensor S4 detects the passage of the medium M near the outlet of the medium supply device 1 on the merging conveying path P3.

[0043] The first entrance passage detection sensor S1, the first exit passage detection sensor S2, and the second entrance passage detection sensor S3 are examples of multiple passage detection sensors that are arranged on multiple individual conveying paths (first individual conveying path P1 and second individual conveying path P2) and detect the passage of the medium M before it reaches the arrival detection sensor (the register sensor S10 described later).

[0044] 2 has a processor (e.g., CPU: Central Processing Unit) that functions as an arithmetic processing device that controls the operation of the entire medium supplying device 1, and controls each part of the medium supplying device 1. For example, the control unit 31 controls the first to seventh transport roller pairs 21-27 (individual transport section) and the eighth and ninth transport roller pairs 28, 29 (junction transport section) using the first to fourth transport drive units D1-D4. Note that in cases where the medium supplying device 1 is provided integrally with a destination device such as the printing device 101, the control unit of the destination device (e.g., control unit 151 of the printing device 101 described later) may function as the control unit 31.

[0045] The storage unit 32 has, 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, or 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 storage area as necessary when a processor executes various control programs. Note that in cases where the medium supplying device 1 is provided integrally with a destination device such as the printing device 101, a storage unit of the destination device (for example, a storage unit 152 of the printing device 101 described later) may function as the storage unit 32.

[0046] The interface unit 33 transmits and receives various information to and from external devices such as the printing device 101. For example, the interface unit 33 receives information such as a request to start supplying the medium M and the timing of arrival at a registration sensor, which will be described later, from the interface unit 153 of the printing device 101, and the control unit 31 controls the operation of each part of the medium supplying device 1 based on this information.

[0047] Next, the printing device 101 will be described.

[0048] 1 and 2, the printing device 101 includes a printing unit 110, a suction conveying unit 120, a conveying unit 130, a registration sensor S10, a destination conveying path P11, a circulating inverting conveying path P12, an inverting unit 140, a control unit 151, a storage unit 152, and an interface unit 153. In addition, in Fig. 1, the junction conveying path P3 and the destination conveying path P11 are indicated by solid lines, and the circulating inverting conveying path P12 is indicated by dashed lines.

[0049] The printing unit 110 has, for example, a line-head type inkjet head (not shown) for each color used for printing. The printing method of the printing unit 110 may be a printing method other than the inkjet printing method.

[0050] 1, the suction transport unit 120 is disposed so as to face the printing unit 110. The suction transport unit 120 transports the medium M by a transport belt while suctioning the medium M.

[0051] The conveying section 130 has a registration roller pair 131 that corrects skew of the medium M by being abutted against the medium M conveyed toward the printing section 110, a receiving roller pair 132 that conveys the medium M in the junction conveying path P3 continuing from the medium supply device 1, and a plurality of conveying roller pairs 133 that convey the medium M in the destination conveying path P11 or the circulating inverted conveying path P12. The registration roller pair 131, the receiving roller pair 132, and the plurality of conveying roller pairs 133 convey the medium M while nipping it.

[0052] The registration sensor S10 is disposed near the registration roller pair 131 in the junction conveying path P3 on the upstream side in the conveying direction of the registration roller pair 131. The registration sensor S10 is disposed in the junction conveying path P3 and is an example of an arrival detection sensor that detects an arrival timing, which is an example of the arrival time of the medium M. This arrival detection sensor may be the above-mentioned second exit passage detection sensor S4 disposed in the junction conveying path P3 of the medium supplying device 1. As described above, since the medium supplying mechanism in this embodiment includes the medium supplying device 1 and a conveying path configuration up to the registration roller pair 131 of the printing device 101, the receiving roller pair 132 and the registration sensor S10 can be said to be part of the medium supplying mechanism.

[0053] The destination transport path P11 is connected to the junction transport path P3 continuing from the medium supply device 1, and extends downstream in the transport direction from the registration roller pair 131. In the printing system 100 shown in Fig. 1, when other printing devices or medium ejection devices are disposed downstream in the transport direction of the printing device 101, the destination transport path P11 is connected to the transport paths of these devices.

[0054] The medium M is transported along the circulatory reversal transport path P12 when, for example, the opposite side of the medium M that has been printed on one side by the printing unit 110 is to be printed on as well.

[0055] The reversing section 140 has a reversing path that reverses the front and back of the medium M transported to the circulatory reversing transport path P12, a pair of switchback rollers, and the like.

[0056] The control unit 151 shown in FIG. 2 has a processor (for example, a CPU) that functions as an arithmetic processing unit that controls the overall operation of the printing device 101, and controls each unit of the printing device 101.

[0057] The storage unit 152 has memories such as a ROM, which is a read-only semiconductor memory in which a specific control program is pre-recorded, and a RAM, which is a semiconductor memory that can be written and read at any time and is used as a working memory area as necessary when the processor executes various control programs.

[0058] The interface unit 153 transmits and receives various information to and from the medium supplying device 1 and external devices such as a user terminal that transmits print data. For example, as described above, the interface unit 153 transmits information such as a supply start request for the medium M and a registration sensor arrival timing, which will be described later, to the interface unit 33 of the medium supplying device 1.

[0059] The operation of the medium supplying device 1 will be described below while omitting points that overlap with the above description as appropriate.

[0060] First, when the interface unit 33 receives a request to start supplying medium M from the printing device 101 (interface unit 153), the control unit 31 shown in Figure 2 controls the first supply unit 11 and the second supply unit 12 shown in Figure 1 to supply medium M alternately or only one of the medium M.

[0061] When the control unit 31 causes the first supply unit 11 to supply the medium M, the control unit 31 controls the first to fifth transport roller pairs 21-25 using the first transport drive unit D1 and the second transport drive unit D2 to transport the medium M supplied from the first supply unit 11 along the first individual transport path P1. When the medium M is transported along the first individual transport path P1, its passage is detected by the first entrance passage detection sensor S1 and the first exit passage detection sensor S2.

[0062] When the control unit 31 causes the second supply unit 12 to supply the medium M, the control unit 31 controls the sixth and seventh transport roller pairs 26, 27 using the third transport drive unit D3 to transport the medium M supplied from the second supply unit 12 along the second individual transport path P2. When the medium M is transported along the second individual transport path P2, its passage is detected by the second inlet passage detection sensor S3.

[0063] In addition, the control unit 31 controls the eighth and ninth conveying roller pairs 28, 29 using the fourth conveying drive unit D4 so as to convey the medium M conveyed from the first individual conveying path P1 or the second individual conveying path P2 to the merging conveying path P3. When the medium M is conveyed to the merging conveying path P3, its passage is detected by the second exit passage detection sensor S4.

[0064] As a result, the medium M is supplied to the junction conveying path P3 of the printing device 101 connected to the junction conveying path P3 of the medium supplying device 1, and after the medium M is abutted against the registration roller pair 131 to correct the skew, it is printed by the printing unit 110. When the medium M is transported on the junction conveying path P3 of the printing device 101, its passage (arrival) is detected by the registration sensor S10. The timing of the arrival of the medium M at the registration sensor S10 is determined by sending the medium M from the printing device 101 (interface unit 153) to the medium supplying device 1 (interface unit 33).

[0065] Next, the process of adjusting the transport speed of the medium M in the medium supplying device 1 will be described.

[0066] Fig. 4 to Fig. 6 are diagrams showing the relationship between the transport speed of the medium M and elapsed time in the medium supply mechanism of the present embodiment. Fig. 7 and Fig. 8 are diagrams showing the relationship between the transport speed of the medium M and elapsed time in the medium supply mechanisms of Comparative Examples 1 and 2. Note that Fig. 4 to Fig. 8 are examples in which the medium M is supplied from the second supply unit 12.

[0067] 4, when the second supply unit 12 starts supplying the medium M, the medium M is gradually accelerated and then transported to the second individual transport path P2 at a constant speed by the suction transport unit 12b. When the medium M is transported to the second inlet passage detection sensor S3 (time t11a), the control unit 31 controls the sixth and seventh transport roller pairs 26, 27 of the second individual transport path P2 and the eighth and ninth transport roller pairs 28, 29 of the junction transport path P3 to transport the medium M at a transport speed v1.

[0068] The passing timing (time t11a), which is an example of the passing time of the medium M through the second inlet passing detection sensor S3, is delayed from the reference passing timing (time t11), which is a theoretical value determined in advance, due to a large amount of slippage between the medium M and the suction conveying unit 12b and a low conveying rate. Therefore, as shown in FIG. 7 (Comparative Example 1), in order to make up for the delay of the medium M, the control unit 31 determines the conveying speed v1 between the second inlet passing detection sensor S3 and the second outlet passing detection sensor S4 (the second individual conveying path P2 and the merging conveying path P3) so that the conveying speed v1 is faster than the conveying speed v0 between the second outlet passing detection sensor S4 and the registration sensor S10. The passing time, which is an example of the passing timing, and the arrival time, which is an example of the arrival timing described later, are not limited to the instant of the passing timing and the arrival timing, but include within the approximate error range. For example, the control unit 31 may obtain the passage time and arrival time as approximate timing by rounding off or cutting off the timing detected by the second entrance passage detection sensor S3, the registration sensor S10, etc. to a predetermined place.

[0069] Furthermore, as described above, the second individual conveying path P2 connected to the second supply section 12 has a third curved portion C3, and the merging conveying path P3 of the medium supply device 1 and the printing device 101 has a fourth curved portion C4, so that the path length of the medium M conveyed on the second individual conveying path P2 and the merging conveying path P3 is shorter when the medium M is thick paper Ma than when the medium Mb is thin paper.

[0070] 7, the passing timing (time t12a) detected by the second outlet passing detection sensor S4 becomes faster than the reference passing timing (time t12) which is a predetermined theoretical value. Also, the arrival timing (time t13a) of the thick sheet Ma as the arrival time at the registration sensor S10 becomes faster than the reference arrival timing (time t13) as the reference arrival time which is a predetermined theoretical value. And, the abutment timing of the thick sheet Ma, which is an example of the abutment time at which the thick sheet Ma abuts against the registration roller pair 131, becomes faster than the reference abutment timing (time t14) which is an example of the reference abutment time.

[0071] 7, the passing timing (time t12b) detected by the second exit passing detection sensor S4 is later than the reference passing timing (time t12). Also, the arrival timing (time t13b) of the thin sheet Mb at the registration sensor S10 is later than the reference arrival timing (time t13). And, the abutment timing of the thin sheet Mb against the registration roller pair 131 is later than the reference abutment timing (time t14).

[0072] As described above, if there is variation in the timing at which thick paper Ma and thin paper Mb hit the registration roller pair 131, the ability to correct skew of the medium M (the amount of skew correction due to the difference in the correction period) will vary, resulting in a decrease in image quality in the printed result or the occurrence of a jam.

[0073] 4, when the medium M is thick paper Ma, the control unit 31 adjusts the conveying speed v1 to be slower to a conveying speed v1a between the second entrance passage detection sensor S3 and the second exit passage detection sensor S4 (the second individual conveying path P2 and the merging conveying path P3). Note that the degree to which the control unit 31 slows the conveying speed v1 to the conveying speed v1a may be determined in advance based on the measurement results by, for example, measuring in advance by experiment the deviation from the reference passing timing of the passing timing of the second exit passage detection sensor S4 and the registration sensor S10 when the medium M is plain paper and when the medium M is thick paper Ma.

[0074] 4, when the medium M is thin paper Mb, the control unit 31 adjusts the conveying speed v1 to be faster to a conveying speed v1b between the second entrance passage detection sensor S3 and the second exit passage detection sensor S4 (the second individual conveying path P2 and the merging conveying path P3). The degree to which the control unit 31 increases the conveying speed v1 to the conveying speed v1b may also be determined in advance by, for example, measuring the difference in the passing timing of the second exit passage detection sensor S4 and the registration sensor S10 when the medium M is plain paper and when it is thin paper Mb through experiments.

[0075] When the medium M is transported to the second exit passage detection sensor S4 (time t12), the control unit 31 controls the eighth and ninth transport roller pairs 28, 29 of the junction transport path P3 to transport the medium M at a transport speed v0. In addition, the receiving roller pair 132 of the printing device 101 transports the medium M at the same transport speed v0 as the eighth and ninth transport roller pairs 28, 29.

[0076] As a result, the registration sensor S10 detects the passage (arrival) of medium M (time t13), and after the conveying speed is decelerated by the conveying section 130 to reduce the collision noise with the registration roller pair 131, medium M strikes the registration roller pair 131 at a constant speed (time t14). Thereafter, the receiving roller pair 132 stops the conveyance of medium M. Note that by not stopping the conveyance of medium M when medium M strikes the registration roller pair 131 (time t14), the receiving roller pair 132 subsequently conveys medium M slightly to slacken it and correct the skew.

[0077] 5, as a result of less slippage between the medium M and the suction conveying unit 12b and a higher conveying rate, the passing timing (time t11b) of the medium M through the second inlet passage detection sensor S3 may become faster than the reference passing timing (time t11), which is a predetermined theoretical value. In this case, as also shown in FIG 8 (Comparative Example 2), the control unit 31 determines the conveying speed v2 between the second inlet passage detection sensor S3 and the second outlet passage detection sensor S4 (second individual conveying path P2 and junction conveying path P3) so that the conveying speed v2 is slower than the conveying speed v0 between the second outlet passage detection sensor S4 and the registration sensor S10. In addition, such a deviation in the passing timing (times t11a, t11b) of the second inlet passing detection sensor S3 of media M from the reference passing timing (time t11) is not limited to when the topmost media M, which has been floated by the floating air and separated from the lower media M by the separation air, is adsorbed and transported by the suction transport sections 11b, 12b, but also occurs due to friction acting between the separation plate and media M when the topmost media M and the lower media M are separated by a separation plate or the like.

[0078] As described above, for the thick sheet of paper Ma shown by the thick dashed line in Fig. 8, the passing timing (time t12a) detected by the second exit passing detection sensor S4 is faster than the reference passing timing (time t12), and the arrival timing (time t13a) at the registration sensor S10 is faster than the reference arrival timing (time t13). For the thin sheet of paper Mb shown by the thin dashed line in Fig. 8, the passing timing (time t12b) detected by the second exit passing detection sensor S4 is slower than the reference passing timing (time t12), and the arrival timing (time t13b) at the registration sensor S10 is slower than the reference arrival timing (time t13).

[0079] 5, when the medium M is thick paper Ma, the control unit 31 adjusts the conveying speed v2 between the second inlet passage detection sensor S3 and the second outlet passage detection sensor S4 (the second individual conveying path P2 and the merging conveying path P3) to slow down the conveying speed v2 to a conveying speed v2a. When the medium M is thin paper Mb, the control unit 31 adjusts the conveying speed v2 between the second inlet passage detection sensor S3 and the second outlet passage detection sensor S4 (the second individual conveying path P2 and the merging conveying path P3) to speed up the conveying speed v2 to a conveying speed v2b.

[0080] 4, when the medium M is transported to the second exit passage detection sensor S4 (time t12), the control unit 31 controls the eighth and ninth transport roller pairs 28, 29 of the junction transport path P3 to transport the medium M at a transport speed v0. In addition, the receiving roller pair 132 of the printing device 101 transports the medium M at the same transport speed v0 as the eighth and ninth transport roller pairs 28, 29.

[0081] As a result, the passage (arrival) of the medium M is detected by the registration sensor S10 (time t13), and the conveying speed of the medium M is decelerated by the receiving roller pair 132 to reduce the collision noise with the registration roller pair 131, and then the medium M strikes the registration roller pair 131 at a constant speed (time t14). After that, the receiving roller pair 132 stops conveying the medium M.

[0082] 4 and 5 (and FIGS. 7 and 8 of comparative examples) show an example in which the medium M is supplied from the second supply unit 12. However, when the medium M is supplied from the first supply unit 11, the reference passing timing of the second inlet passage detection sensor S3 at time t11 may be replaced with the reference passing timing of the first inlet passage detection sensor S1, and the same process may be performed. However, the first individual conveying path P1 connected to the first supply unit 11 has a first curved portion C1 having a larger corner angle than the third curved portion C3 of the second individual conveying path P2, and also has a second curved portion C2. Therefore, the difference in path length between when the medium M conveyed on the first individual conveying path P1 is thick paper Ma and when the medium M is thin paper Mb is thick paper Ma is larger than the medium M conveyed on the second individual conveying path P2. Therefore, the control unit 31 adjusts the conveying speed of the medium M supplied from the first supply unit 11 to be slower for thick paper Ma and faster for thin paper Mb, differently from the adjustment of the conveying speed of the medium M supplied from the second supply unit 12. In addition, if the conveying path (first individual conveying path P1 and the merging conveying path P3, or the second individual conveying path P2 and the merging conveying path P3) connected to the first supply section 11 or the second supply section 12 does not have a curved portion (first to fourth curved portions C1 to C4), it can be said that there is no difference in path length due to the thickness of the medium M described above for the medium M conveyed on a conveying path that does not have a curved portion, and therefore adjustment of the conveying speed can be omitted.

[0083] As described above, the control unit 31 adjusts the transport speeds v1 and v2 of the medium M based on the thickness, which is an example of medium information of the medium M, and the shape of the transport path of the medium M, but as shown in Fig. 6, there may be a discrepancy between the arrival timing, which is the detection result of the registration sensor S10 acquired by the control unit 31, and the predetermined reference arrival timing (time t13). Note that the control unit 31 may use a timer to measure the arrival timing based on the timing of a supply start request for the medium M received from the printing device 101, the start of the supply operation, etc.

[0084] 6, when the arrival timing at the registration sensor S10 is time t13c, which is later than time t13, the control unit 31 controls the sixth to ninth conveying roller pairs 26-29 to increase the above-mentioned conveying speeds v1, v1a, and v1b of the succeeding medium M between the second inlet passage detection sensor S3 and the second outlet passage detection sensor S4 (the second individual conveying path P2 and the merging conveying path P3) to a conveying speed v1c (a different speed for each of the original conveying speeds v1, v1a, and v1b) indicated by a thick dotted line. As described above, the conveying speeds v1, v1a, and v1b vary depending on the passing timing of the second inlet passage detection sensor S3, and therefore are not necessarily the same for the preceding medium M and the succeeding medium M. As shown in FIG. 5, if the passing timing (time t11b) of the subsequent medium M through the second inlet passing detection sensor S3 becomes faster than a predetermined reference passing timing (time t11), the control unit 31 may control the sixth to ninth conveying roller pairs 26-29 to increase the conveying speed from the conveying speeds v2, v2a, and v2b.

[0085] Furthermore, as shown by the thin dashed line in Figure 6, when the arrival timing is time t13d which is earlier than the reference arrival timing (time t13), the control unit 31 controls the sixth to ninth conveying roller pairs 26-29 so as to slow down the conveying speeds v1, v1a, v1b of the subsequent medium M between the second inlet passage detection sensor S3 and the second outlet passage detection sensor S4 (the second individual conveying path P2 and the merging conveying path P3) to the conveying speed v1d shown by the thin dotted line (a different speed for each of the original conveying speeds v1, v1a, v1b).

[0086] When the medium M is continuously supplied only from the second supply unit 12, the subsequent medium M is, for example, the medium M two sheets behind the preceding medium M with a shift between the arrival timing (times t13c, t13d) and the reference arrival timing (time t13). However, the subsequent medium M may be the medium M transported next to the preceding medium M with the shift. When the subsequent medium M has already been supplied from the second supply unit 12 and transported on the second individual transport path P2, the transport speed may be adjusted during transport on the second individual transport path P2. Furthermore, when the medium M is supplied alternately from the first supply unit 11 and the second supply unit 12, the subsequent medium M is, for example, the medium M supplied from the second supply unit 12 one sheet behind the preceding medium M with the shift.

[0087] The control unit 31 may adjust how many sheets of medium M the subsequent medium M is transported after, based on at least one of the length in the transport direction and the transport speed of the medium M, and the length in the transport direction of the second individual transport path P2. Since the length in the transport direction of the second individual transport path P2 is different from that of the first individual transport path P1, it may adjust how many sheets of medium M the subsequent medium M is transported after for each of the individual transport paths P1 and P2, between the second individual transport path P2 to which the medium M is supplied from the second supply unit 12 and the first individual transport path P1 to which the medium M is supplied from the first supply unit 11.

[0088] As described above, the control unit 31 feeds back the deviation between the arrival timing (times t13c, t13d) of the preceding medium M at the registration sensor S10 and the reference arrival timing (time t13) to the conveyance speed of the succeeding medium M, thereby bringing the arrival timing of the succeeding medium M at the registration sensor S10 closer to the reference arrival timing (time t13), and thus bringing the abutment timing at which the succeeding medium M abuts against the registration roller pair 131 closer to the reference abutment timing (time t14). This suppresses variation in the skew correction amount (correction period) of the medium M.

[0089] 6, the control unit 31 determines the transport speed of the subsequent medium M between the second inlet passage detection sensor S3 and the second outlet passage detection sensor S4 (second individual transport path P2 and junction transport path P3) based on the difference between the arrival timing at the registration sensor S10 (times t13c and t13d) and the reference arrival timing (time t13), but the transport speed of the subsequent medium M between the second inlet passage detection sensor S3 and the second outlet passage detection sensor S4 (second individual transport path P2 and junction transport path P3) may be determined based on the difference between the arrival timing at the second outlet passage detection sensor S4 and the reference arrival timing (time t12). In this way, the control unit 31 may obtain the arrival timing of the medium M, which is the detection result of the second outlet passage detection sensor S4 (an example of an arrival detection sensor) arranged on the junction transport path P3.

[0090] Incidentally, the control unit 31 adjusts the conveying speeds v1 and v2 between the second entrance passage detection sensor S3 and the second exit passage detection sensor S4 (the second individual conveying path P2 and the merging conveying path P3) to conveying speeds v1a, v1b, v2a, and v2b, and adjusts the conveying speeds v1, v1a, and v1b to conveying speeds v1c and v1d, instead of between the second exit passage detection sensor S4 and the registration sensor S10 of the succeeding medium M (the merging conveying path P3 and the supply destination conveying path P11). This allows the adjustment of the conveying speed to be completed only by the medium supplying device 1. On the other hand, when the conveying speed is adjusted by both the medium supplying device 1 and the printing device 101, the conveying speed by the eighth and ninth conveying roller pairs 28 and 29 of the medium supplying device 1 and the conveying speed by the receiving roller pair 132 of the printing device 101 do not match, and the medium M may be pulled toward the printing device 101 or become loose. This discrepancy in conveying speed is due to differences in the measurement results of the timing at which the medium M reaches the registration sensor S10 between the medium supplying device 1 and the printing device 101, due to limitations in the measurement accuracy of the communication (inter-board communication) between the interface unit 33 of the medium supplying device 1 and the interface unit 153 of the printing device 101 and the firmware.For example, a difference of 1 msec results in a difference in conveying speed of approximately 20 mm / s.

[0091] Unlike the above description, it is possible to make the timing of the preceding medium M hitting the registration roller pair 131 closer to a constant by adjusting the conveying speed between the registration sensor S10 of the preceding medium M and the registration roller pair 131 based on the arrival timing of the preceding medium M at the registration sensor S10. However, in this case, the conveying speed when hitting the registration roller pair 131 is not constant, which makes the amount of skew correction prone to variation.

[0092] Incidentally, when the medium M is transported so that the timing of contact with the registration roller pair 131 is delayed from the reference contact timing, the next medium M is also usually transported so that the timing of contact with the registration roller pair 131 is delayed from the reference contact timing.

[0093] In this case, for example, when the conveying speeds v1, v1a, and v1b between the second entrance passage detection sensor S3 and the second exit passage detection sensor S4 (second individual conveying path P2 and merging conveying path P3) shown in Fig. 6 are adjusted to be faster than the conveying speed v1c, the next medium M approaches the preceding medium M that is conveyed with a delay. As a result, for example, while the preceding medium M is abutting against the registration roller pair 131, the next medium M collides with the preceding medium M, causing a jam, or it becomes impossible to secure time to change the rotation speed of the sixth and seventh conveying roller pairs 26, 27 in the second individual conveying path P2 or the eighth and ninth conveying roller pairs 28, 29 in the merging conveying path P3 in the gap between the preceding medium M and the next medium M.

[0094] Therefore, especially when the gap between multiple media M is small or the transport speed is fast, the control unit 31 may determine the transport speed of the subsequent medium M so as to eliminate part of the deviation from the reference arrival timing (time t13) of the arrival timing of the medium M at the registration sensor S10 (times t13c, t13d) rather than eliminating the deviation all at once with the subsequent medium M.

[0095] In the present embodiment described above, the medium supply mechanism includes a first supply unit 11 and a second supply unit 12 which are an example of a supply unit that supplies the medium M, a first individual conveyance path P1, a second individual conveyance path P2, and a junction conveyance path P3 which are connected to the first supply unit 11 and the second supply unit 12 and are an example of a conveyance path having curved portions (first to fourth curved portions C1 to C4), first to ninth conveyance roller pairs 21 to 29 and a receiving roller pair 132 which are an example of a conveyance unit that conveys the medium M on the conveyance paths, and a control unit 31 which controls the first to ninth conveyance roller pairs 21 to 29. The control unit 31 adjusts the conveyance speed of the medium M by the first to ninth conveyance roller pairs 21 to 29 based on the thickness, which is an example of medium information of the medium M, and the shape of the conveyance path of the medium M.

[0096] Incidentally, in the first to third curved portions C1 to C3 of the first individual conveying path P1 and the second individual conveying path P2 and the fourth curved portion C4 of the merging conveying path P3, the positions through which the medium M passes differ depending on the type of medium M (for example, differences in stiffness due to differences in thickness), which causes differences in the path length through which the medium M actually passes. In this regard, in the present embodiment, the control unit 31 adjusts the conveying speed based on medium information such as the thickness of the medium M and the shape of the conveying path for the medium M, so that it is possible to suppress variations in the arrival timing of the medium M at, for example, the pair of registration rollers 131 of the supply destination device (printing device 101) caused by the above-mentioned differences in path length. Thus, according to the present embodiment, it is possible to suppress variations in the arrival timing (arrival time) due to the type of medium M conveyed in the conveying paths (first individual conveying path P1, second individual conveying path P2, and merging conveying path P3) having curved portions (first to fourth curved portions C1 to C4). This makes it possible, for example, to suppress deviations in the timing at which the medium M strikes the registration roller pair 131 of the printing device 101, thereby preventing variations in the ability to correct the skew of the medium M, which could result in a deterioration in the image quality of the printed result or the occurrence of a jam.

[0097] In the present embodiment, the medium supply mechanism includes a first supply unit 11 and a second supply unit 12, which are examples of a plurality of supply units, and the transport path includes a first individual transport path P1 and a second individual transport path P2, which are examples of a plurality of individual transport paths connected to the first supply unit 11 and the second supply unit 12, both of which (at least one example) have curved portions (first to third curved portions C1 to C3), and a junction transport path P3, which is a junction of the first and second individual transport paths P1 and P2. The control unit 31 adjusts the transport speed of the medium M, which is supplied from the first supply unit 11 and the second supply unit 12 and transported by the first to ninth transport roller pairs 21 to 29, based on medium information such as the thickness of the medium M and the transport path shape of the medium M (the transport path shape passing through the first individual transport path P1 and the junction transport path P3, or the transport path shape passing through the second individual transport path P2 and the junction transport path P3).

[0098] This makes it possible to suppress fluctuations in the timing at which the medium M reaches a destination device such as the printing device 101, which is caused by differences in path length due to the type of medium M, for each of the medium M supplied from the first supply unit 11 and the medium M supplied from the second supply unit 12, based on the transport path shape and medium information such as the thickness of the medium M supplied from each of the first supply unit 11 and the second supply unit 12. This makes it possible to avoid widening the supply interval of the medium M to allow for fluctuations in the arrival timing, for example, when the medium M supplied from the first supply unit 11 and the medium M supplied from the second supply unit 12 are transported alternately, and thus makes it possible to suppress a decrease in productivity (the supply speed and printing speed per sheet of medium M).

[0099] Furthermore, in this embodiment, the medium supply mechanism includes a second inlet passage detection sensor S3 (or a first inlet passage detection sensor S1) that is disposed on each of the first individual transport path P1 and the second individual transport path P2 and is an example of a passage detection sensor that detects the passage of the medium M before it reaches the registration sensor S10. The control unit 31 determines the transport speed of the medium M based on the difference between the passage timing (times t11a, t11b) that is an example of the passage time of the medium M detected by the second inlet passage detection sensor S3 and the reference passage timing (time t11) that is an example of a predetermined reference passage time, the thickness that is an example of medium information of the medium M, and the transport path shape of the medium M.

[0100] This makes it possible to suppress fluctuations in the timing at which the medium M reaches the destination device, such as the printing device 101, caused by discrepancies in the supply speed or supply start timing of the medium M from the first supply section 11 and the second supply section 12 to the first individual conveying path P1 or the second individual conveying path P2.

[0101] In addition, in this embodiment, the control unit 31 adjusts the transport speed of the trailing medium M by the first to ninth transport roller pairs 21 to 29 based on the deviation between the arrival timing (times t13c and t13d shown in FIG. 6), which is an example of the arrival time of the preceding medium M, which is the detection result of the registration sensor S10 (or the second exit passage detection sensor S4), which is an example of an arrival detection sensor arranged on the merging transport path P3, and the reference arrival timing (time t13), which is an example of a predetermined reference arrival time, the thickness, which is an example of media information of the trailing medium M, and the shape of the transport path for the medium M.

[0102] This allows the transport speed of the subsequent medium M to be adjusted based on the difference between the arrival timing (times t13c and t13d) of the preceding medium M at the registration sensor S10 relative to the subsequent medium M and the predetermined reference arrival timing (time t13). Furthermore, the transport speed of the subsequent medium M is adjusted based on the deviation of the preceding medium M rather than being adjusted after deviation occurs during transport, so that it is easy to suppress fluctuations in the arrival timing of the medium M at the destination device such as the printing device 101. Furthermore, in cases where the deviation in the transport speed differs between the first individual transport path P1 and the second individual transport path P2 due to differences in the length in the transport direction, the transport roller pairs arranged, and the transport drive unit, the transport speed can be adjusted for each of the first individual transport path P1 and the second individual transport path P2.

[0103] <Other embodiments> Each unit of the printing system of this embodiment can be the same as each unit of the printing system 100 described in the above-mentioned embodiment. Therefore, in this embodiment, the description of the matters that overlap with the above-mentioned embodiment will be omitted.

[0104] FIG. 9 is a diagram showing the transport time of the medium M supplied from the first supply unit 11 (thick line) and the second supply unit 12 (thin line) in another embodiment (first supply unit v0=second supply unit v0).

[0105] FIG. 10 is a diagram showing the transport time of the medium M supplied from the first supply section 11 (thick line) and the second supply section 12 (thin line) in Comparative Example 3 (first supply section v0=second supply section v0, medium: thin).

[0106] FIG. 11 is a diagram showing the transport time of the medium M supplied from the first supply section 11 (thick line) and the second supply section 12 (thin line) in Comparative Example 4 (first supply section v0=second supply section v0, medium: thick).

[0107] FIG. 12 is a diagram showing the transport time of the medium M supplied from the first supply unit 11 (thick line) and the second supply unit 12 (thin line) in another embodiment (first supply unit v0>second supply unit v0).

[0108] FIG. 13 is a diagram showing the transport time of the medium M supplied from the first supply section 11 (thick line) and the second supply section 12 (thin line) in Comparative Example 5 (first supply section v0>second supply section v0, medium: thin).

[0109] FIG. 14 is a diagram showing the transport time of the medium M supplied from the first supply section 11 (thick line) and the second supply section 12 (thin line) in Comparative Example 6 (first supply section v0>second supply section v0, medium: thick).

[0110] Note that the examples of Figures 9 to 11 are examples where the reference conveying speed v0 of the medium M supplied from the first supply section 11 is the same as the reference conveying speed v0 of the medium M supplied from the second supply section 12, and the examples of Figures 12 to 14 are examples where the reference conveying speed v0 of the medium M supplied from the first supply section 11 is faster than the reference conveying speed v0 of the medium M supplied from the second supply section 12.

[0111] As shown in Figures 9 and 12, consider a case in which medium M (medium M1) supplied from the first supply unit 11, medium M (medium M2) supplied from the second supply unit 12, medium M (medium M3) supplied from the first supply unit 11, and medium M (medium M4) supplied from the second supply unit 12, that is, medium M supplied from the first supply unit 11 and medium M supplied from the second supply unit 12 alternately (with at least two consecutive supply unit switches) to arrive at a registration roller pair 131 (the right end of the thick and thin lines in the figure) at a constant arrival interval in10 or arrival interval in20 (an example of a reference arrival time). Note that the reference arrival time, which is, for example, a constant arrival interval in10 or arrival interval in20, can vary for each sheet of medium M or for each supply unit (first supply unit 11 or second supply unit 12) depending on the size of the medium M, the print content (printing time in the printing unit 110), etc.; however, here we consider the case where A3-sized media M1 to M4 are caused to arrive at the registration roller pair 131 at a constant arrival interval in10 or arrival interval in20.

[0112] In this case, as described above, the first individual conveying path P1 shown in FIG. 1 is longer in the conveying direction of the medium M than the second individual conveying path P2, so when the conveying speeds of the first individual conveying path P1 and the second individual conveying path P2 are the same, the conveying time of the media M1 and M3 supplied from the first supply unit 11 is longer than the conveying time of the media M2 and M4 supplied from the second supply unit 12.

[0113] Therefore, the supply start times t31, t32 or t51, t52 of medium M1, M3 from the first supply unit 11 are set earlier than the supply start times t41, t42 or t61, t62 of medium M2, M4 from the second supply unit 12 in comparison with the arrival time at the registration roller pair 131. Also, in order to make medium M reach the registration roller pair 131 at a constant arrival interval in10 or arrival interval in20, as shown in the above-mentioned Figures 4 to 6, the control unit 31 also adjusts the above-mentioned conveying speed, such as adjusting the conveying speed of medium M by the first to ninth conveying roller pairs 21-29 based on the thickness, which is an example of medium information of medium M, and the shape of the conveying path of medium M.

[0114] Here, even if the arrival interval in10 or the arrival interval in20 of the media M1 to M4 is constant, the supply start times of the media M1 to M4 are not constant. In other words, if the supply start times of the media M1 to M4 are constant, the arrival times at the registration roller pair 131 will not be constant due to the difference in length in the transport direction between the first individual transport path P1 and the second individual transport path P2.

[0115] It is also possible to adjust the conveying speed of the first individual conveying path P1, which is longer in the conveying direction, faster than the conveying speed of the second individual conveying path P2, so that the supply start times of the media M1 to M4 are at regular intervals and the arrival times of the media M1 to M4 at the registration roller pair 131 are at regular intervals. Even when adjusting the conveying speeds of the first individual conveying path P1 and the second individual conveying path P2 in this way, it is effective to adjust the conveying speed of the medium M by the first to ninth conveying roller pairs 21 to 29 based on the thickness of the medium M and the shape of the conveying path of the medium M, as described above.

[0116] 3(a)-(c), the first individual transport path P1 has a first curved portion C1 with a larger corner angle than the third curved portion C3 of the second individual transport path P2, and also has a second curved portion C2, so that the difference in path length between when the medium M transported on the first individual transport path P1 is thick paper Ma and when the medium M is thin paper Mb is larger than when the medium M is transported on the second individual transport path P2. As a result, when the media M1-M4 are thin paper, the transport path length is more likely to be longer on the first individual transport path P1 than on the second individual transport path P2. Also, when the media M1-M4 are thick paper, the transport path length is more likely to be shorter on the first individual transport path P1 than on the second individual transport path P2.

[0117] Therefore, if the control unit 31 does not adjust the transport speed of the medium M by the first to ninth transport roller pairs 21-29 based on the thickness of the medium M and the shape of the transport path of the medium M, when the media M1-M4 are thin paper, the transport time of the media M1 and M3 supplied from the first supply unit 11 is more susceptible to the influence (time extension) of the media being thin paper than the transport time of the media M2 and M4 supplied from the second supply unit. As a result, unlike the constant arrival interval in10 or arrival interval in20 in Figures 9 and 12, as shown in Figures 10 (Comparative Example 3) and 13 (Comparative Example 5), the arrival interval in11 or arrival interval in21 between the media M1 and M3 supplied from the first supply unit 11 reaching the registration roller pair 131 and the media M2 and M4 supplied from the second supply unit 12 reaching the registration roller pair 131 is shorter than the arrival interval in12 or arrival interval in22 between the media M3 supplied from the first supply unit 11 reaching the registration roller pair 131 after the media M2 supplied from the second supply unit 12 reaching the registration roller pair 131.

[0118] Furthermore, if the control unit 31 does not adjust the transport speed of the medium M by the first to ninth transport roller pairs 21-29 based on the thickness of the medium M and the shape of the transport path of the medium M, when the media M1-M4 are thick paper, the transport time of the media M1 and M3 supplied from the first supply unit is more susceptible to the influence (time reduction) of the media being thick paper than the transport time of the media M2 and M4 supplied from the second supply unit. As a result, unlike the constant arrival interval in10 or arrival interval in20 in Figures 9 and 12, as shown in Figures 11 (Comparative Example 4) and 14 (Comparative Example 6), the arrival interval in13 or arrival interval in23 until the media M2 and M4 supplied from the second supply unit 12 reach the registration roller pair 131 after the media M1 and M3 supplied from the first supply unit 11 reach the registration roller pair 131 becomes longer than the arrival interval in14 or arrival interval in24 until the media M3 supplied from the first supply unit 11 reaches the registration roller pair 131 after the media M2 supplied from the second supply unit 12 reaches the registration roller pair 131.

[0119] As shown in Figs. 10, 11, 13, and 14, if the arrival intervals in11 to in14 or the arrival intervals in21 to in24 are not constant, as described above, the timing of the medium M hitting the registration roller pair 131 of the printing device 101 will be shifted, causing the ability to correct the skew of the medium M to vary, resulting in a decrease in image quality as a printed result or the occurrence of a jam. Alternatively, in order to prevent the image quality from decreasing or to prevent a jam from occurring, the arrival intervals will be widened in consideration of the variation in the arrival intervals, resulting in a decrease in productivity. Therefore, it is desirable to adjust the transport speed of the medium M by the first to ninth transport roller pairs 21 to 29 based on the thickness of the medium M and the transport path shape of the medium M as described above, and to make the arrival intervals in10 or the arrival intervals in20 constant as shown in Figs. 9 and 12.

[0120] In addition, when the supply unit is not frequently switched, such as when the supply of the medium M loaded on the loading platform 12a of the second supply unit 12 is started after the supply of all the media M loaded on the loading platform 11a of the first supply unit 11 is completed, the arrival interval is easily made constant for the media M continuously supplied from the same supply unit (the first supply unit 11 or the second supply unit 12) because the thickness (medium information) of the medium M and the transport path shape are transported under the same conditions. Therefore, when the supply unit is not frequently switched, the fluctuation in the arrival interval that occurs when the supply unit is switched may be ignored. In this way, when the fluctuation in the arrival interval is ignored, the take-in start time of the pair of registration rollers 131 and the printing start time of the printing unit 110 are less likely to affect the printing of the medium M if they are determined based on the detection timing of the medium M by the registration sensor S10.

[0121] In the other embodiments described above, the same effects can be obtained with respect to matters similar to those of the above-mentioned embodiment, such as the ability to suppress variations in arrival time depending on the type of medium M transported in a transport path having a curved portion.

[0122] In addition, in this embodiment, the first individual conveying path P1 is longer in the conveying direction of the medium M than the second individual conveying path P2, and the control unit 31, 151 determines supply start times t31, t32 or t51, t52 for causing the first supply unit 11 to supply media M1, M3 and supply start times t41, t42 or t61, t62 for causing the second supply unit 12 to supply media M2, M4 so that media M1, M3 supplied from the first supply unit 11 and media M2, M4 supplied from the second supply unit 12 reach a reference arrival position (e.g., a pair of registration rollers 131) in the merging conveying path P3 at a reference arrival time (e.g., a fixed arrival interval in10, in20).

[0123] Therefore, compared to a case where medium M is supplied to the first supply unit 11 or the second supply unit 12 at constant intervals, medium M1, M3 supplied from the first supply unit 11 and medium M2, M4 supplied from the second supply unit 12 can be made to reach the registration roller pair 131 or the like at the reference arrival time (for example, a constant arrival interval in10, in20) without the need for speed correction to eliminate the difference in length in the conveying direction between the first individual conveying path P1 and the second individual conveying path P2. As a result, as described above, the suppression of variation in the arrival time of medium M by adjusting the conveying speed based on medium information such as the thickness of medium M and the shape of the conveying path of medium M can be suppressed from the desired reference arrival time (for example, a constant arrival interval in10, in20).

[0124] In addition, in this embodiment, the control unit 31, 151 determines the supply start times t31, t32 or t51, t52 for causing the first supply unit 11 to supply media M1, M3 and the supply start times t41, t42 or t61, t62 for causing the second supply unit 12 to supply media M2, M4 so that media M1, M3 supplied from the first supply unit 11 and media M2, M4 supplied from the second supply unit 12 alternately (with at least two consecutive supply unit switches) reach the reference arrival position (e.g., the registration roller pair 131) at the reference arrival time (e.g., a fixed arrival interval in10, in20).

[0125] As a result, even if the first individual conveying path P1 and the second individual conveying path P2 have different lengths in the conveying direction and conveying path shapes, the media M1, M3 supplied from the first supply unit 11 and the media M2, M4 supplied from the second supply unit 12 can be made to reach the registration roller pair 131 alternately at the desired reference arrival time (for example, fixed arrival intervals in10, in20).

[0126] 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. In addition, various inventions can be formed by appropriate combinations of 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 inventions described in the claims of the present application as of the beginning and other inventions are listed below.

[0127] [Appendix 1] A supply unit that supplies a medium; a conveying path connected to the supply section and having a curved portion; a transport unit that transports the medium in the transport path; A control unit that controls the transport unit, The control unit adjusts a transport speed of the medium by the transport unit based on medium information of the medium and a transport path shape of the medium. A media supply mechanism comprising: [Appendix 2] A plurality of the supply units are provided, the conveying path includes a plurality of individual conveying paths connected to the plurality of supply units, at least one of which has the curved portion, and a merging conveying path in which the plurality of individual conveying paths join together; The control unit adjusts a transport speed of the medium supplied from each of the plurality of supply units and transported by the transport unit based on the medium information of the medium and the transport path shape of the medium. 2. The medium supply mechanism of claim 1. [Appendix 3] a passage detection sensor disposed on the transport path and configured to detect the passage of the medium; The control unit adjusts a transport speed of the medium by the transport unit based on a difference between a passing time of the medium detected by the passage detection sensor and a predetermined reference passing time, the medium information, and the transport path shape. 3. The medium supply mechanism according to claim 1 or 2. [Additional Notes] The control unit adjusts the transport speed of the subsequent medium by the transport unit based on a difference between an arrival time of the preceding medium, which is a detection result of an arrival detection sensor arranged on the transport path, and a predetermined reference arrival time, medium information of the subsequent medium, and the transport path shape. 4. A medium supply mechanism according to any one of claims 1 to 3. [Appendix 4] The plurality of supply units include a first supply unit and a second supply unit, the plurality of individual transport paths include a first individual transport path connected to the first supply unit and a second individual transport path connected to the second supply unit; the first individual transport path has a length in a transport direction of the medium that is longer than the second individual transport path; The control unit determines a supply start time for causing the first supply unit to supply the medium and a supply start time for causing the second supply unit to supply the medium such that the medium supplied from the first supply unit and the medium supplied from the second supply unit reach a reference arrival position on the junction transport path at a reference arrival time. 3. The medium supply mechanism according to claim 2. [Appendix 5] The control unit determines the supply start time at which the first supply unit supplies the medium and the supply start time at which the second supply unit supplies the medium such that the medium supplied from the first supply unit and the medium supplied from the second supply unit alternately reach the reference arrival position at the reference arrival time. 5. The medium supply mechanism according to claim 4. [Explanation of symbols]

[0128] 1 Media supply device 1a Upper 1b Lower 11 1st supply section 11a Loading platform 11b Suction transport section 11c Media thickness setting section 12 2nd supply section 12a Loading platform 12b Suction transport section 12c Media thickness setting section 21-29 1st to 9th conveyor roller pairs 31 Control Unit 32 Storage section 33 Interface section 100 Printing System 101 Printing device 110 Printing Department 120 Suction conveying section 130 Conveyor 131 Registration roller pair 132 Reception Roller 133 Transport roller pair 140 Inversion section 151 Control section 152 Storage section 153 Interface section C1~C4 1st to 4th curved sections D1 to D4 First to fourth conveyor drive units M medium Ma Cardboard Mb Thin Paper P1 First individual transport path P2 Second individual transport path P3 Converging transport route P11 Destination transport route P12 Circulation reversing conveyor S1 First entrance passage detection sensor S2 First exit passage detection sensor S3 Second entrance passage detection sensor S4 2nd exit passage detection sensor S10 Resist Sensor

Claims

1. A supply unit that supplies a medium; a conveying path connected to the supply section and having a curved portion; a transport unit that transports the medium in the transport path; A control unit that controls the transport unit; a passage detection sensor that is disposed upstream of the curved portion of the conveying path in a conveying direction of the medium and detects the passage of the medium; The control unit adjusts a transport speed of the medium by the transport unit in the curved portion based on a difference between a passing time of the medium detected by the passage detection sensor and a predetermined reference passing time, medium information of the medium, and a transport path shape of the medium. A media supply mechanism comprising:

2. A plurality of the supply units are provided, the conveying path includes a plurality of individual conveying paths connected to the plurality of supply units, at least one of which has the curved portion, and a merging conveying path in which the plurality of individual conveying paths join together; The control unit adjusts the transport speed of the medium supplied from each of the plurality of supply units and transported by the transport unit based on a difference between the passing time and the reference passing time, the medium information of the medium, and the transport path shape of the medium.

2. The media supply mechanism of claim 1.

3. The plurality of supply units include a first supply unit and a second supply unit, the plurality of individual transport paths include a first individual transport path connected to the first supply unit and a second individual transport path connected to the second supply unit; the first individual transport path is longer in the transport direction than the second individual transport path; The control unit determines a supply start time for causing the first supply unit to supply the medium and a supply start time for causing the second supply unit to supply the medium such that the medium supplied from the first supply unit and the medium supplied from the second supply unit reach a reference arrival position on the junction transport path at a reference arrival time.

3. The medium supply mechanism according to claim 2.

4. The control unit determines the supply start time at which the first supply unit supplies the medium and the supply start time at which the second supply unit supplies the medium such that the medium supplied from the first supply unit and the medium supplied from the second supply unit alternately reach the reference arrival position at the reference arrival time.

4. The medium supply mechanism according to claim 3.

Images