Printing device

Abstract

To more reliably perform automatic paper feeding from a mounted roll.SOLUTION: A control part switches from a state where a sheet is being supplied from a roll held by a first holding part to a state where the sheet is being supplied from a roll held by a second holding part. In the case of switching, the control part rolls back the sheet which was being supplied to the roll held by the first holding part.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a printing apparatus that draws out and supplies a sheet from a roll on which a continuous sheet is wound. [Background technology]

[0002] Patent Document 1 discloses a printing device that can automatically feed a sheet by detecting the leading edge of the sheet on a loaded roll. In this device, an optical sensor detects the leading edge of the sheet while rotating the roll in the winding direction opposite to the supply direction, and when the detection is complete, the roll is rotated in the supply direction, the sheet is peeled off from the roll, and the separated sheet is fed into the device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-37557 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the configuration of Patent Document 1, even if the leading edge of the sheet on the roll can be detected correctly, the leading edge of the sheet may not proceed to a normal feeding path in the subsequent feeding operation, causing a conveyance failure such as a paper jam. Patent Document 1 does not disclose any solution to such a problem.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a printing apparatus that can more reliably perform automatic feeding of a loaded roll. [Means for solving the problem]

[0006] To this end, the present invention provides a printing apparatus including a first holding unit that holds a roll around which a sheet is wound so that it can rotate in a first direction in which the sheet is supplied and a second direction opposite to the first direction, a first sensor that detects an end of the sheet of the roll held by the first holding unit, a second holding unit that holds the roll around which a sheet is wound so that it can rotate in the first direction and the second direction, a second sensor that detects the end of the sheet of the roll held by the second holding unit, and a control unit that executes a first automatic sheet feed, which is a control to rotate the roll in the second direction when a roll is set in the first holding unit, to detect an end of the sheet of the roll by the first sensor, and then change the rotation direction of the roll from the second direction to the first direction and insert the sheet for the first time into a first supply port, and a second automatic sheet feed, which is a control to rotate the roll in the second direction when a roll is set in the second holding unit, to detect an end of the sheet of the roll by the second sensor, and then change the rotation direction of the roll from the second direction to the first direction and insert the sheet for the first time into a second supply port, but supply Be From the state in which the roll is held by the second holding part The second automatic feeder Switch to sheet supply mode, The second automatic sheet feeder is in a state where sheets are fed. When switching, The sheet that was being supplied The film is characterized in that it is rewound onto a roll held by the first holding section. Effect of the Invention

[0007] According to the present invention, automatic feeding of the installed roll can be performed more reliably. [Brief description of the drawings]

[0008] [Figure 1] 1 is a perspective view of a printing apparatus according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is an explanatory diagram of a sheet transport path in the printing apparatus. [Diagram 3] FIG. 2 is an explanatory diagram of a sheet supplying device. [Figure 4] FIG. 13 is an explanatory diagram of the sheet supplying device when the roll outer diameter is small. [Diagram 5] FIG. 2 is a block diagram for explaining a control system of the printing apparatus. [Figure 6] 10 is a flowchart illustrating a sheet supply preparation operation. [Figure 7] FIG. 2 is a detailed view of the sensor unit. [Figure 8] 5A to 5C are diagrams illustrating various feeding states of a sheet during feeding. [Figure 9] 11A and 11B are diagrams illustrating output values ​​of a sensor unit corresponding to feeding states. [Figure 10] 10 is a flowchart illustrating steps of a sheet leading end setting process. [Figure 11] 10A to 10C are diagrams illustrating a method for setting a threshold value used in the sheet leading edge setting process. [Figure 12] 13 is a diagram showing the mounting position of a vibration sensor used in the second embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the accompanying drawings. First, a basic configuration of the present invention will be described.

[0010] (Basic configuration) 1 to 6 are explanatory diagrams of the basic configuration of a printing device as an application example of the present invention. The printing device of this example is an inkjet printing device including a sheet supplying device for supplying a sheet as a printing medium, and a printing section for printing an image on the sheet. For the sake of explanation, coordinate axes are set as shown in the figures. That is, the sheet width direction of the roll R is set as the X-axis direction, the direction in which the sheet is transported in the printing section 400 described later is set as the Y-axis direction, and the direction of gravity is set as the Z-axis direction.

[0011] 1, in the printing device 100 of this example, rolls R (rolled sheets) each made of a long continuous sheet (sometimes called a web) wound into a roll can be set in two roll holders, an upper one and a lower one. An image is printed on the sheet 1 selectively pulled out from the rolls R. Using various switches provided on the operation panel 28, the user can input various commands to the printing device 100, such as specifying the size of the sheet 1 and switching between online and offline.

[0012] FIG. 2 is a schematic cross-sectional view of the main part of the printing apparatus 100. Two sheet supply devices 200 corresponding to two rolls R are arranged one above the other. The sheet 1 drawn from the roll R by the supply devices 200 is transported by a sheet transport unit (transport mechanism) 300 along a sheet transport path to a printing unit 400 capable of printing an image. The printing unit 400 prints an image on the sheet 1 by ejecting ink from an inkjet print head 18. The print head 18 ejects ink from an ejection port using an ejection energy generating element such as an electrothermal conversion element (heater) or a piezoelectric element. The print head 18 is not limited to an inkjet type, and the printing method of the printing unit 400 is not limited to a specific type, and may be, for example, a serial scan type or a full line type. In the case of the serial scan type, an image is printed by the transport operation of the sheet 1 and the scanning of the print head 18 in a direction intersecting the transport direction of the sheet 1. In the case of the full-line method, a long print head 18 extending in a direction intersecting the conveying direction of the sheet 1 is used, and an image is printed while the sheet 1 is conveyed continuously.

[0013] The roll R is set in the roll holding section of the supplying device 200 with the spool member 2 inserted in the hollow hole, and the spool member 2 is driven in forward and reverse rotation by a roll driving motor 33 (see FIG. 5). The supplying device 200 is equipped with a drive section 3, an arm member (moving body) 4, an arm rotating shaft 5, a sensor unit 6, a swinging member 7, driven rotating bodies (contact bodies) 8 and 9, a separation flapper (upper guide body) 10, and a flapper rotating shaft 11, as described below.

[0014] The conveying guide 12 guides the front and back sides of the sheet 1 pulled out from the supply device 200, and leads the sheet 1 to the print section 400. The conveying roller 14 is rotated forward and backward in the directions of arrows D1 and D2 by a motor 35 (see FIG. 5) for driving the conveying roller, which will be described later. The nip roller 15 is rotatable in response to the rotation of the conveying roller 14, and can be moved toward and away from the conveying roller 14 and the nip force can be adjusted by a motor 37 (see FIG. 5) for adjusting the nip force. The conveying speed of the sheet 1 by the conveying roller 14 is set higher than the pulling speed of the sheet 1 by the rotation of the roll R, so that a back tension is applied to the sheet 1, and the sheet 1 can be conveyed in a taut state.

[0015] A platen 17 of the printing unit 400 regulates the position of the sheet 1, and a cutter 20 cuts the sheet 1 on which an image has been printed. A cover 42 of the roll R prevents the sheet 1 on which an image has been printed from returning to the supply device 200. Such operations in the printing device 100 are controlled by a CPU 201 (see FIG. 5), which will be described later.

[0016] FIG. 3 is an explanatory diagram of the supplying device 200, and in FIG. 3(a), the roll R has a relatively large outer diameter.

[0017] An arm member (moving body) 4 is attached to the conveying guide 12 by a rotating shaft 5 so as to be rotatable in the directions of the arrows A1 and A2. A guide portion 4b (lower guide body) that guides the lower surface of the sheet 1 pulled out from the roll R is formed on the upper portion of the arm member 4. A torsion coil spring 3c that presses the arm member 4 in the direction of the arrow A1 is interposed between the arm member 4 and a rotating cam 3a of the driving unit 3. The rotating cam 3a is rotated by a motor (see FIG. 5) 34 for adjusting the pressure force, which will be described later, and the force with which the torsion coil spring 3c presses the arm member 4 in the direction of the arrow A1 changes depending on the rotation position. As will be described later, when the leading end of the sheet 1 is set in the sheet supply port between the arm member 4 and the separation flapper 10, the pressing force of the arm member 4 by the torsion coil spring 3c is switched between three levels depending on the rotation position of the rotating cam 3a. That is, the pressing state can be switched between a pressing state with a relatively small force (pressing force of a weak nip), a pressing state with a relatively large force (pressing force of a strong nip), and a pressing force release state.

[0018] A swinging member 7 is attached to the arm member 4 so as to be able to swing freely, and first and second driven rotors (rotating bodies) 8, 9, which are positioned offset in the circumferential direction of the roll R, are rotatably attached to the swinging member 7. These driven rotors 8, 9 are pressed against the outer periphery of the roll R from below in the direction of gravity by a pressing force in the direction of arrow A1 applied to the arm member 4. That is, the driven rotors 8, 9 are pressed against the outer periphery of the roll R from below in the direction of gravity relative to the horizontal central axis of the roll R. The pressing force is changed according to the pressing force that presses the arm member 4 in the direction of arrow A1.

[0019] A number of arm members 4, each having a swinging member 7, are provided at different positions in the X-axis direction. The swinging member 7 is provided with a bearing portion 7a and a shaft fastener portion 7b as shown in Fig. 3(b), which receive the rotating shaft 4a of the arm member 4 with a predetermined play.

[0020] The bearing portion 7a is provided at the center of gravity of the oscillating member 7, and is supported by the rotating shaft 4a so that the oscillating member 7 is in a stable position in each of the X-axis, Y-axis, and Z-axis directions. In addition, since the rotating shaft 4a is received with some play, the oscillating member 7 at any position in the X-axis direction is displaced so as to follow the outer periphery of the roll R by the pressing force against the arm member 4 in the direction of the arrow A1. This configuration (equalizing mechanism) allows the first and second driven rotors 8, 9 to change their pressing positions against the outer periphery of the roll R. As a result, the contact area between the sheet 1 and the first and second driven rotors 8, 9 is always kept at a maximum, and the pressing force against the sheet 1 is equalized, thereby suppressing variation in the conveying force of the sheet 1. The driven rotors 8, 9 are pressed against the outer periphery of the roll R, thereby suppressing the occurrence of slack in the sheet 1 and increasing its conveying force.

[0021] A separation flapper 10 located above the arm member 4 is attached to the main body (printer main body) of the printing device 100 so as to be rotatable around a rotation shaft 11 in the directions of arrows B1 and B2. The separation flapper 10 is configured to abut against and lightly press the outer circumferential surface of the roll R by its own weight. If it is necessary to press the roll R more strongly, a biasing force from a biasing member such as a spring may be used. A driven roller 10a is rotatably provided at the contact portion of the separation flapper 10 with the roll R to suppress the effect of the pressing force on the sheet 1. Also, a separation portion 10b at the tip of the separation flapper 10 is formed to extend as close as possible to the surface of the roll R in order to make it easier to separate the tip of the sheet from the roll R.

[0022] The sheet 1 is pulled out from the roll R by passing over the driven rotors 8, 9, and its underside is guided by the guide portion 4b at the top of the arm member 4, and then is supplied through a supply path formed between the separation flapper 10 and the arm member 4. In this manner, the driven rotors 8, 9 are pressed against the outer periphery of the roll R from below, and the underside of the sheet 1 pulled out by passing over the driven rotors 8, 9 is guided by the guide portion 4b. This allows the sheet 1 to be smoothly supplied by utilizing the weight of the sheet 1. In addition, the driven rotors 8, 9 and the guide portion 4b move according to the roll outer diameter of the roll R, so that the sheet 1 can be reliably pulled out from the roll R and conveyed regardless of the outer diameter of the roll R.

[0023] One of the features of the device of this embodiment is an automatic sheet loading function (automatic sheet feeding function). In automatic loading, when a user sets an unused roll R in the device, the device detects the leading edge of the sheet while rotating the roll R in a direction (called the second direction) opposite to the sheet supply (sheet feeding) direction. Next, the device rotates the roll R in the rotation direction (called the forward direction or the first direction) when the sheet is supplied, and automatically feeds out the leading edge of the sheet separated from the roll R. The sensor unit 6 detects that the leading edge of the sheet 1 has peeled off from the outer peripheral surface of the roll R and the sheet has been peeled off (sheet separation). The leading edge of the sheet 1 detected by the sensor unit 6 is automatically inserted into the sheet supply port between the arm member 4 and the separation flapper 10 and is fed out. A more detailed procedure of this automatic loading function will be described later.

[0024] In addition, since this example includes two supply devices 200, one above the other, it is possible to switch from a state in which the sheet 1 is being supplied from one supply device 200 to a state in which the sheet 1 is being supplied from the other supply device 200. In such a case, one supply device 200 rewinds the sheet 1 that it had been supplying onto the roll R. The leading edge of the sheet 1 is retracted to a position where it can be detected by the sensor unit 6 or another sheet edge sensor provided in the vicinity of the sensor unit 6.

[0025] FIG. 4 is an explanatory diagram of the supply device 200 when the outer diameter of the roll R is relatively small.

[0026] Since the arm member 4 is constantly pressed in the direction of the arrow A1 by the torsion coil spring 3c, it rotates in the direction of the arrow A1 in response to the reduction in the outer diameter of the roll R. Moreover, by rotating the rotating cam 3 in response to the change in the outer diameter of the roll R, the pressing force of the arm member 4 by the torsion coil spring 3c can be maintained within a predetermined range regardless of the change in the outer diameter of the roll R. Furthermore, since the separation flapper 10 is constantly pressed in the direction of the arrow B1, it rotates in the direction of the arrow B1 in response to the reduction in the outer diameter of the roll R. As a result, even if the outer diameter of the roll R becomes smaller, the separation flapper 10 forms a supply path between itself and the conveying guide 12, and guides the upper surface of the sheet 1 with its lower surface 10c. In this way, the arm member 4 and the separation flapper 10 rotate in response to the change in the outer diameter of the roll R, and a supply path of a substantially constant size is formed between them regardless of the outer diameter of the roll R.

[0027] FIG. 5 is a block diagram for explaining an example of the configuration of a control system in the printing apparatus 100. The CPU 201 of the printing apparatus 100 controls each part of the printing apparatus 100 including the supply device 200, the sheet conveying section 300, and the printing section 400 according to a control program stored in the ROM 204. The type, width, and various setting information of the sheet 1 are input to the CPU 201 from the operation panel 28 via the input interface 202. The CPU 201 is also connected to various external devices 29 including a host device such as a personal computer via an external interface 205, and exchanges various information such as print data with the external devices 29. The CPU 201 also writes and reads information related to the sheet 1 to and from the RAM 203. The motor 33 is a roll driving motor for rotating the roll R forward and backward via the spool member 2, and constitutes a driving mechanism (rotation mechanism) capable of rotating the roll R. The pressing force adjustment motor 34 is a motor that rotates the rotating cam 3a to adjust the pressing force against the arm member 4, and the transport roller drive motor 35 is a motor that rotates the transport roller 14 forward and reverse. The roll sensor 32 is a sensor that detects the spool member 2 of the roll R when the roll R is set in the supply device 200. The roll rotation amount sensor 36 is a sensor that detects the rotation amount of the roll R, and is, for example, a rotary encoder that outputs a number of pulses according to the rotation amount of the roll R.

[0028] FIG. 6 is a flowchart for explaining the supply preparation process for the sheet 1, which starts with setting of the roll R.

[0029] The CPU 201 of the printing apparatus 100 waits in a state where the arm member 4 is pressed in the direction of the arrow A1 by a "weak nip pressing force" (weak nip state), and first determines whether the roll R is set (step S1). In this example, when the roll sensor 32 detects the spool member 2 of the roll R, it determines that the roll R is set. After the roll R is set, the CPU 201 switches the arm member 4 to a state where the arm member 4 is pressed in the direction of the arrow A1 by a "strong nip pressing force" (strong nip state) (step S2). Next, a sheet leading edge setting process is executed to insert the leading edge of the sheet 1 into the sheet supply port between the arm member 4 and the separation flapper 10 (step S3). The leading edge of the sheet 1 is inserted into the supply port by this sheet leading edge setting process (automatic loading). A more detailed operation will be described later.

[0030] Thereafter, the CPU 201 rotates the roll R in the direction of the arrow C1 by the roll driving motor 33 (see FIG. 5) to start supplying the sheet 1 (step S4). When the leading edge of the sheet 1 is detected by the sheet sensor 16 (step S5), the CPU 201 rotates the conveying roller 14 forward in the direction of the arrow D1 to pick up the leading edge of the sheet 1, and then stops the motor 33 and the motor 35 (step S6). Thereafter, the CPU 201 releases the pressing force that presses the arm member 4 in the direction of the arrow A1, and separates the first and second driven rotors 8 and 9 from the roll R (nip release state) (step S7).

[0031] After that, the CPU 201 detects whether the sheet is conveyed in the sheet conveying section 300 while being inclined (skewed). Specifically, the sheet 1 is conveyed a predetermined distance in the sheet conveying section 300, and the amount of skew occurring at that time is detected by a carriage carrying the print head 18 or a sensor provided in the sheet conveying section 300. If the amount of skew is larger than a predetermined allowable amount, the sheet 1 is fed and back-fed repeatedly with forward and reverse rotation of the conveying roller 14 and the roll R while applying back tension to the sheet 1. By such an operation, the skew of the sheet 1 is corrected (step S8). In this way, by setting the supply device 200 to a nip release state during the correction of the skew of the sheet 1 and during the image printing operation on the sheet 1, it is possible to avoid the influence of the driven rotors 8 and 9 on the correction accuracy of the skew of the sheet 1 and the printing accuracy of the image. Thereafter, the CPU 201 causes the sheet conveying unit 300 to move the leading edge of the sheet 1 to a standby position (fixed position) in the printing unit 400 before printing starts (step S9). This completes preparation for supplying the sheet 1. Thereafter, the sheet 1 is pulled out from the roll R as the roll R rotates, and is conveyed to the printing unit 400 by the sheet conveying unit 300.

[0032] Hereinafter, as an embodiment of the present invention, the sheet leading edge setting process (step S3) in FIG. 5 in the basic configuration of the printing apparatus 100 will be described.

[0033] (First embodiment) FIG. 7 is a detailed view of the sensor unit 6 used in this embodiment. The sensor unit 6 is provided with an optical sensor 60 including a light-emitting unit 6c such as an LED, OLED, or LD, and a light-receiving unit 6d such as a photodiode. The light-receiving unit 6d detects the light emitted from the light-emitting unit 6c and reflected by the downward surface of the rolled sheet (the outer surface of the sheet that was the outer peripheral surface of the roll and is the surface to be printed by the printing unit). At this time, the shorter the distance between the optical sensor 60 and the rolled sheet, the greater the amount of light received by the light-receiving unit 6d, and the greater the output value. Conversely, the longer the distance, the less the amount of light received by the light-receiving unit 6d, and the smaller the output value of the sensor 60.

[0034] Here, consider a case where, under the above configuration, the CPU 201 rotates the roll R clockwise (C2 direction) while detecting the output of the optical sensor 60. At this time, the leading edge F of the sheet falls off the driven roller 10a of the separation flapper 10 and onto the arm member 4, and then passes the detection position of the optical sensor 60 on the sensor unit 6. In this embodiment, the leading edge of the sheet 1 is detected by detecting a change in the detection output of the optical sensor 60 at this time.

[0035] A more detailed description will be given. When the leading edge F of the sheet 1 passes through the driven roller 10a of the separation flapper 10 and falls onto the arm member 4 as the roll R rotates in the C2 direction, the optical sensor 60 and the surface of the sheet 1 detected by the optical sensor 60 suddenly approach each other, and the output value of the optical sensor 60 changes from a low value to a high value. When the roll R further rotates in the C2 direction, the high output value is maintained for a while, but when the leading edge F of the sheet passes the detection position of the optical sensor 60, the distance between the optical sensor 60 and the surface of the sheet 1 detected by the optical sensor 60 widens again, and the output value of the optical sensor 60 transitions to a low value. The CPU 201 detects such a change in the output value in association with the amount of rotation detected by the roll rotation amount sensor 36, and thereby determines whether the leading edge F of the sheet has passed. The CPU 201 then feeds the sheet 1 into the supply port, starting from the leading edge F of the sheet detected by the above method.

[0036] Figures 8(a) to (c) are diagrams showing various feeding states of the sheet 1 during feeding. Figures 9(a) and (b) are diagrams showing output values ​​V of the sensor unit 6 corresponding to each of the feeding states shown in Figures 8(a) to (c). In Figures 9(a) and (b), the horizontal axis represents the rotation angle θ of the roll R, and the vertical axis represents the output value V of the optical sensor 60.

[0037] Fig. 8(a) shows a state in which the sheet S is normally fed along the arm member 4. In Fig. 8(a), the sheet 1 advances along the conveying guide 12 while being supported by it, and no sheet jam occurs. At this time, the sheet 1 advances close to the optical sensor 60, and the output value V is maintained at a high value as shown by the dashed line L0 in Figs. 9(a) and (b).

[0038] Fig. 8(b) shows a state in which the sheet 1 being fed is buckled due to a bent or broken leading edge F of the sheet abutting against the driven roller 10a. The sheet 1A shown by the solid line in Fig. 8(b) is raised above the arm member 4 and is further away from the sensor unit 6 than in Fig. 8(a). In this case, the output value V of the sensor unit 6 is maintained at a low value after a certain rotation angle, as shown by the solid line L1 in Fig. 9(a). In this embodiment, when a change in the output of the sensor unit 6 as shown by the solid line L1 is detected, the CPU 201 determines that there is a risk of a sheet jam occurring.

[0039] On the other hand, in Fig. 8(b), sheet 1B, indicated by the dotted line, is buckled but part of it is in a position close to sensor unit 6. In this case, the output value V of optical sensor 60 remains high, and the output value at this point cannot be distinguished from the normal feeding as shown in Fig. 8(a). However, if roll R is further rotated in the C1 direction from this state, sheet 1B will change to a bellows state as shown in sheet 1C in Fig. 8(c).

[0040] When the bellows-like sheet 1C advances with the rotation of the roll R, the distance between the optical sensor 60 and the sheet 1 increases and decreases. Therefore, the output value V of the optical sensor 60 repeatedly increases and decreases after a certain rotation angle, as shown by the solid line L2 in Fig. 9(b). Therefore, in this embodiment, even if an output change as shown by the solid line L2 is detected during feeding, it is determined that there is a concern that a sheet jam may occur.

[0041] Fig. 10 is a flowchart for explaining specific steps executed by the CPU 201 in the sheet leading edge setting process shown in step S3 of Fig. 6. This process is mainly composed of an edge detection process for detecting the edge of the sheet 1, and a determination process (jam detection process) for determining the feeding state of the sheet 1 with the detected edge as the leading edge.

[0042] When this process starts, first in step S101, the CPU 201 starts detecting the output of the optical sensor 60. Next, the CPU 201 proceeds to step S102 and starts rotating the roll R in the C2 direction. Specifically, the roll driving motor 33 is driven while the roll rotation amount sensor 36 counts the amount of rotation of the roll R, and the roll R is rotated at a constant speed in the winding direction, i.e., in the C2 direction in the figure.

[0043] Next, the CPU 201 proceeds to step S103 and determines whether the output value V of the optical sensor 60 has switched from Low to High with respect to a predetermined threshold value T0. Here, switching from Low to High means that the leading edge F of the sheet has come off the driven roller 10a of the separation flapper 10 and fallen onto the arm member 4. The CPU 201 continues to detect the output of the optical sensor 60 until such a switch from Low to High is confirmed. If it is determined in step S103 that the determination result of the optical sensor 60 has switched from Low to High, the CPU proceeds to step S104.

[0044] Furthermore, in step S104, the CPU 201 determines whether the output value V of the optical sensor 60 has switched from High to Low with respect to the threshold value T0. Here, switching from High to Low means that the leading edge F of the sheet has passed over the sensor unit 6. The CPU 201 continues to detect the output of the optical sensor 60 until such switching from High to Low is confirmed. If it is determined in step S104 that the determination result of the optical sensor 60 has switched from High to Low, the CPU proceeds to step S105, determines that the leading edge F of the sheet has been detected, and stores the current rotation angle in the RAM 203. Then, the CPU proceeds to step S106, where it stops the rotation of the roll R in the C2 direction.

[0045] Next, the CPU 201 proceeds to step S107 and resets the counter N (N=0). The counter N is a variable for counting the number of times that the output value of the optical sensor 60 fluctuates beyond a predetermined threshold value after the start of the feeding operation.

[0046] In step S108, the CPU 201 starts rotating the roll R in the forward direction (the direction C1 in the figure). Specifically, the roll driving motor 33 is driven while the roll rotation amount sensor 36 counts the amount of rotation of the roll R, to rotate the roll R in the sending direction, that is, the direction C1 in the figure. As a result, the sheet 1 advances between the arm member 4 and the separation flapper 10, with the sheet leading edge F detected in step S105 at the head.

[0047] In step S109, the CPU 201 determines whether a predetermined amount of rotation has been exceeded since the start of rotation of the roll R in step S108. Here, the predetermined amount of rotation is an amount of rotation that can be regarded as the sheet 1 having normally reached the sheet supply port when no abnormality in the conveyance of the sheet 1 is detected. If it is determined that the predetermined amount of rotation has been exceeded, the CPU 201 ends the output detection of the optical sensor 60 in step S117, and ends this process, i.e., the sheet leading edge setting process (step S3 in FIG. 6). On the other hand, if the predetermined amount of rotation has not been exceeded in step S109, the CPU 201 proceeds to step S110.

[0048] In step S110, the CPU 201 determines whether the output value V of the optical sensor 60 is within a range between predetermined thresholds T1 and T2. In this embodiment, the thresholds T1 and T2 are thresholds for determining whether the sheet 1 is in a buckled state as indicated by the solid line 1A in FIG. 8(b).

[0049] When the sheet 1 passing over the sensor unit 6 changes to a state as shown by the solid line 1A with the rotation of the roll R in the C1 direction, the sensor 60 and the sheet 1 transition from a close proximity state to a separated state, and the sensor output value decreases. In this embodiment, the upper limit threshold T2 is a sensor output value below which the separated state is deemed to have occurred. The method for setting the threshold T2 is not particularly limited, but for example, the following method can be adopted.

[0050] First, as shown in Fig. 11(a), an output value Fv obtained when the sensor 60 detects the outer peripheral surface of the roll R before the sheet leading edge F reaches the detection area of ​​the sensor 60 is obtained in advance. Also, as shown in Fig. 11(b), an output value Nv obtained when the sensor 60 detects the surface of the sheet 1 that is normally conveyed after the sheet leading edge F has passed the detection area of ​​the sensor 60 is obtained in advance. Then, using these, a lower limit threshold T2 is calculated according to the following formula. T2 = (Fv + Nv) / 2 x 0.2

[0051] Here, the average values ​​of Fv and Nv are set taking into consideration a fluctuation of about 20% in the output value caused by meandering or floating of the sheet 1.

[0052] On the other hand, in the output value V of the optical sensor 60 while rotating the roll R, even if the sheet 1 is advancing normally, the output value V may suddenly fluctuate as shown in FIG. 12 due to an impact caused by disturbance or the like. In this case, although the output value V rapidly decreases, it recovers early and is independent of the conveyance state of the sheet 1, and it is preferable that the output fluctuation is ignored. Therefore, in the present embodiment, a sensor output value for determining that the output value V has dropped too far below the upper limit threshold value T2 and is a disturbance fluctuation is set as the lower limit threshold value T1. The lower limit threshold value T1 is not particularly limited, but can be set using, for example, the following formula. T1 = Fv × 0.8

[0053] Here, within the range of normal conveyance, for the lowest Fv that can be assumed, an output value further reduced by 20% is set as the threshold value T1 for distinguishing from a disturbance. In this way, in the present embodiment, in order to reliably detect a buckling state such as the solid line L1 in FIG. 9(a) while excluding sudden fluctuations due to disturbances as shown in FIG. 12, the threshold values T1 and T2 are prepared.

[0054] Return to the flowchart of FIG. 10. When the output value V satisfies T1 < V < T2 in step S110, the CPU 201 determines that the sheet 1 is in a buckling state (jam state) and jumps to step S115. Then, after stopping the rotation of the roll R, it proceeds to step S116 and executes predetermined error processing. Specifically, the leading end of the sheet 1 cannot be set normally, and a message indicating a feeding failure is displayed on the display of the operation panel to prompt the user to check the sheet 1.

[0055] On the other hand, when the output value V does not satisfy T1 < V < T2 in step S110, the CPU 201 proceeds to step S111 and uses threshold values T3 and T4 different from the threshold values T1 and T2 to determine whether the sheet 1 is in a bellows state like the solid line 1C shown in FIG. 8(c).

[0056] When the sheet 1 advances in a bellows state like the solid line 1C, the optical sensor 60 and the sheet 1 repeatedly approach and separate from each other. Therefore, in the present embodiment, a lower limit threshold value T3 for determining separation and an upper limit threshold value T4 for determining proximity are prepared, and when they fluctuate a predetermined number of times (Tn) between them, it is determined that the sheet 1 is in a bellows state. At this time, the lower limit threshold value T3 is preferably set to a value larger than the upper limit threshold value T2 for discriminating the buckling state described above. Here, these threshold values T3 and T4 are set according to the following formula. T3 = (Fv + Nv) × 0.2 T4 = (Fv + Nv) × 0.4

[0057] Return to the flowchart of FIG. 10. In step S111, the CPU 201 determines whether the sensor output value V satisfies T3 > V. When T3 > V is not satisfied, it is considered that no sheet jam has occurred at present, and the CPU 201 returns to step S109 to continue detecting the output of the sensor. On the other hand, when the sensor output value V satisfies T3 > V, the CPU 201 proceeds to step S112.

[0058] In step S112, the CPU 201 determines whether the counter N exceeds a predetermined count threshold value Tn. If not, it proceeds to step S113, waits for the roll R to rotate by a predetermined rotation angle, and then determines whether the output value V satisfies T4 < V. When T4 < V, the CPU 201 considers that one valley in the bellows (that is, the state of T3 > V and the state of T4 < V) has been confirmed, proceeds to S114, and increments the counter N. Then, it returns to step S109 to continue detecting the output of the sensor. On the other hand, when T4 < V is not satisfied, the CPU 201 directly returns to step S109 to continue detecting the output of the sensor.

[0059] When it is determined in step S112 that the counter N has exceeded the counter threshold value Tn, the CPU 201 determines that the sheet 1 is in a bellows state (jammed state). Therefore, the process jumps to step S115 to stop the rotation of the roll R, and then executes a predetermined error process. Then, in step S117, the output detection of the optical sensor 60 is stopped. This ends the process.

[0060] According to the present embodiment described above, it is possible to detect the leading edge of the roll sheet R and to check the state of sheet supply with this leading edge as the leading edge based on the output value of the optical sensor 60 installed on the arm member 4. That is, it is possible to detect a sheet jam early and eliminate it in the sheet leading edge setting process before the sheet 1 is guided into the sheet conveying section 300 or the conveying rollers 14 are driven.

[0061] In the above, the method of setting the thresholds T1 to T4 has been illustrated using formulas, but the method of setting the thresholds is not limited to the above-mentioned method. Even when the same optical sensor is used, the reflectance of the sheet varies depending on the type of sheet, and as a result, Fv and Nv also vary depending on the type of sheet. Furthermore, the distance between the sensor and the sheet suitable for determining the buckling state and the number of peaks and valleys suitable for determining the bellows state also differ depending on the rigidity of the sheet. In other words, it is preferable that the thresholds T1 to T4 and the counter threshold Tn are individually optimized for each type of sheet that the device can mount.

[0062] In the above, the optical sensor 60 including the light emitting portion 6c and the light receiving portion 6d is used as the configuration of the sensor unit 6, but the present invention is not limited to this. For example, the light detected by the light receiving portion 6d does not have to be specularly reflected light, and any sensor configuration can be used as long as the output value changes depending on the distance to the sheet 1 to be detected. For example, a distance sensor such as an ultrasonic sensor or an electrostatic sensor that detects the distance to the target object in a non-contact manner can also be used.

[0063] Furthermore, in the above, the detection of the leading edge F of the sheet and the judgment of a sheet jam are performed based on the output value V of one sensor, but the present invention is not limited to this form. The sheet sensor unit 6 may have a plurality of sensors arranged in the X direction or Y direction. In this case, if the detection of the leading edge F of the sheet and the judgment of a sheet jam are performed using the output values ​​of these plurality of sensors, the detection of the leading edge F of the sheet and the judgment of a sheet jam can be made more reliable.

[0064] In the above, the printing apparatus 100 is described as being capable of holding two roll sheets, but the number of roll sheets that can be held is not limited to this. The printing apparatus 100 may be configured to hold one roll sheet, or may be configured to hold three or more roll sheets. Furthermore, the present invention is not limited to roll sheets, and it is also possible to determine the occurrence of a jam during the transport of cut sheets from a change in the output value of the sensor.

[0065] The present invention can be widely applied as a supplying device for various sheets including paper, film, and cloth, and various sheet processing devices such as a printing device and an image reading device including the supplying device. The image reading device reads the recorded image on the sheet supplied from the supplying device by a reading head. The sheet processing device is not limited to only a printing device and an image reading device, but may be a device that performs various processes (processing, coating, irradiation, inspection, etc.) on the sheet supplied from the supplying device. When the sheet supplying device is configured as an independent device, the device may be provided with a control unit including a CPU. When the sheet supplying device is provided in the sheet processing device, at least one of the supplying device and the sheet processing device may be provided with a control unit including a CPU. [Explanation of symbols]

[0066] 1 sheet 60 Optical Sensor 200 Sheet Feeder 201 CPU R Roll F Sheet End

Claims

1. a first holding section that holds a roll around which a sheet is wound so as to be rotatable in a first direction in which the sheet is supplied and in a second direction opposite to the first direction; a first sensor that detects an edge of the sheet of the roll held by the first holding portion; a second holding section that holds a roll around which a sheet is wound so as to be rotatable in the first direction and the second direction; a second sensor that detects an edge of the sheet of the roll held by the second holding portion; a control unit that executes a first automatic sheet feeder that is a control for rotating a roll in the second direction when a roll is set in the first holding unit, detecting an end of a sheet on the roll with the first sensor, and then changing the rotation direction of the roll from the second direction to the first direction to insert a sheet into a first supply port for the first time, and a second automatic sheet feeder that is a control for rotating a roll in the second direction when a roll is set in the second holding unit, detecting an end of a sheet on the roll with the second sensor, and then changing the rotation direction of the roll from the second direction to the first direction to insert a sheet into a second supply port for the first time, The control unit switches from a state in which a sheet is supplied from a roll held by the first holding unit to a state in which a sheet is supplied from the roll held by the second holding unit by the second automatic paper feed, and when switching to a state in which a sheet is supplied by the second automatic paper feed, rewinds the sheet that was being supplied onto the roll held by the first holding unit.

2. a guide that guides, from a bottom surface of the sheet supplied from the roll held by the first holding unit, and a flapper that moves above the guide in accordance with an outer diameter of the roll held by the first holding unit, 2. The printing apparatus according to claim 1, wherein the first supply port is located between the guide and the flapper.

3. 3. The printing apparatus according to claim 1, further comprising a transport roller that transports the sheet supplied from the roll held by the first holding section and the sheet supplied from the roll held by the second holding section.

4. A sheet sensor is provided to detect the sheet, 4. The printing apparatus according to claim 3, wherein the conveying roller is driven after the sheet is detected by the sheet sensor.

5. 5. The printing apparatus according to claim 1, further comprising a rotation amount sensor for detecting an amount of rotation of the roll held by the first holding portion.

6. A printing device as described in claim 5, characterized in that the end of the sheet is detected by matching the output of the first sensor when the end of the sheet passes through the first sensor with the amount of rotation of the rotation amount sensor.

7. The printing apparatus according to claim 5, characterized in that when the roll held by the first holding section is rotated in the first direction to supply a sheet, a sheet transport abnormality is detected based on the output of the first sensor when the rotation amount detected by the rotation amount sensor does not exceed a predetermined rotation amount at which the sheet is considered to have reached the first supply port, and a threshold value indicating that the sheet is away from the first sensor.

8. 8. A printing apparatus according to claim 5, wherein when the output of the first sensor indicates that the sheet is buckled between a first threshold value and a second threshold value greater than the first threshold value, it is determined that there is an abnormality in the transport of the sheet.

9. Equipped with an operation panel that allows input of roll type and width, 9. The printing apparatus according to claim 1, wherein if a sheet transport error occurs during the first automatic sheet feed, an error is displayed on the operation panel.

10. A first drive unit that rotates the roll held by the first holding unit; 10. The printing apparatus according to claim 1, further comprising: a second drive unit that rotates the roll held by the second holding unit.

11. During the first automatic feeding, after the roll is set in the first holding unit, the roll starts to rotate in the second direction; 11. The printing apparatus according to claim 1, wherein, during the second automatic paper feeding, the roll starts to rotate in the second direction after the roll is set in the second holding section.

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