JP2015013744A - Sheet taking-up device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet taking-up device, enabling stable delivery of a sheet from a taking-up rotor.SOLUTION: A sheet taking-up device includes a taking-up rotor 104 for taking up sheet, and first transportation means 151 which performs transportation of sheet to the taking-up rotor 104 or transportation of sheet from the taking-up rotor 104. When the sheet is delivered from the taking-up rotor 104 by the first transportation means 151, the taking-up rotor 104 rotates by following transportation of sheet by the first transportation means 151.

Description

  The present invention relates to a winding device that winds and feeds a sheet wound in a roll shape, and a sheet processing apparatus and printing apparatus having the winding device.

  Printing devices such as printers, multifunction printers, copiers, facsimile machines, and various device manufacturing apparatuses are widely used. Patent Document 1 discloses a printing apparatus that performs double-sided printing on the front and back of a sheet using a long continuous sheet wound in a roll shape. In this printing apparatus, a sheet printed on the front surface by a printing unit is once wound on a winding rotary member, turned upside down, sent again to the printing unit, and printed on the back surface.

JP 2011-178484 A

However, the printing apparatus of Patent Document 1 has the following problems.
(1) At the time of discharging from the winding rotary body, the sheet wound on the winding rotary body is conveyed in a direction opposite to the winding direction, and thus inertia acts on the sheet. For this reason, an influence due to inertia occurs in the conveyance of the sheet from the winding rotary member to the downstream unit (decal unit, skew feeding correction unit), and stable conveyance cannot be realized.
(2) When the take-up rotating body is controlled so that the conveyance speed of the sheet does not change according to the diameter of the take-up body by the wound sheet at the time of discharging from the take-up rotating body, the control is continuous and If it is not accurate, variations in sheet tension and sagging will occur. Due to fluctuations and sagging of the tension of the sheet, stable conveyance cannot be realized in the downstream unit (decal unit, skew correction unit).

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a sheet winding device that can stably feed out a sheet from a winding rotary body.

  A sheet winding apparatus according to the present invention includes a winding rotary body for winding a sheet, and a first transport unit that transports the sheet to or from the winding rotary body. Have. When the sheet is sent out from the winding rotary member by the first conveying unit, the winding rotary member rotates following the conveyance of the sheet by the first conveying unit.

  According to the present invention, it is possible to send out a stable sheet from the winding rotary member.

FIG. 3 is a schematic diagram illustrating an internal configuration of a printing apparatus having a sheet winding device. It is a block diagram of a control part. It is a figure for demonstrating operation | movement in single-sided printing mode and double-sided printing mode. It is an expansion schematic of a sheet winding device. It is a perspective view which shows the structure of the drive mechanism of a winding rotary body. It is the schematic which shows the structure of a 2nd drive mechanism. It is a flowchart which shows the operation | movement sequence at the time of winding a sheet | seat on a winding rotary body. It is a figure explaining the movement in the sequence of FIG. It is a flowchart which shows the operation | movement sequence at the time of sending out a sheet | seat from a winding rotary body. It is the schematic which shows the mode of the sheet winding apparatus at the time of sending out a sheet | seat from a winding rotary body.

  Details of embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, the same number is attached | subjected to the structure which has the same function in an accompanying drawing, and the description may be abbreviate | omitted.

  The printing apparatus having the sheet winding apparatus of the present invention is a high-speed line printing apparatus that uses a continuous sheet (roll sheet) wound in a roll shape and supports both single-sided printing and double-sided printing. For example, it is suitable for the field of printing a large number of sheets in a print laboratory or the like. The present invention is widely applicable to printers such as printers, printer multifunction devices, copiers, facsimile machines, and various device manufacturing apparatuses. The printing process may be any system such as an inkjet system, an electrophotographic system, a thermal transfer system, a dot impact system, or a liquid development system. Further, the sheet winding apparatus of the present invention is not limited to the printing process, but can be applied to a sheet processing apparatus that performs various processes (recording, processing, coating, irradiation, reading, inspection, etc.) on a roll sheet.

  FIG. 1 is a schematic cross-sectional view illustrating an internal configuration of a printing apparatus having a sheet winding device. The printing apparatus 31 according to the present embodiment can perform double-sided printing on the front surface (first surface) and the back surface (second surface) of a sheet using a sheet wound in a roll shape. In the printing apparatus 31, there are roughly a sheet supply unit 1, a decurling unit 2, a skew correction unit 3, a printing unit 4, an inspection unit 5, a cutter unit 6, an information recording unit 7, a drying unit 8, a reversing unit 9, Each unit includes a discharge conveyance unit 10, a sorter unit 11, a discharge unit 12, and a control unit 13. A sheet is conveyed by a conveyance mechanism including a roller pair and a belt along a sheet conveyance path indicated by a solid line in the drawing, and is processed in each unit.

  The sheet supply unit 1 is a unit for holding and supplying a sheet S wound in a roll shape. The sheet supply unit 1 can store two rolls R <b> 1 and R <b> 2, and is configured to pull out and supply the sheet S alternatively. The number of rolls that can be stored is not limited to two, and one or three or more rolls may be stored.

  The decurling unit 2 is a unit that reduces curling (warping) of the sheet supplied from the sheet supply unit 1. In the decurling unit 2, two pinch rollers are used for one driving roller, and the sheet is curved and passed so as to give a curl in the opposite direction of the curl, thereby applying a decurling force to reduce the curl. As will be described later, the decurling unit 2 can adjust the decurling force.

  The skew correction unit 3 is a unit that corrects the skew of the sheet S that has passed through the decurling unit 2 (inclination with respect to the original traveling direction). The sheet skew is corrected by pressing the sheet end on the reference side against the guide member.

  The print unit 4 is a unit that forms an image by performing print processing on the sheet S from above with the print head 14. That is, the printing unit 4 is a processing unit that performs a predetermined process on the sheet S (in this embodiment, a processing unit that performs a printing process). The printing unit 4 also includes a plurality of conveyance rollers that convey the sheet. The print head 14 has a line type print head in which an inkjet nozzle row is formed in a range that covers the maximum width of the sheet S that is assumed to be used. The print head 14 has a plurality of print heads arranged in parallel along the transport direction. In this example, there are seven print heads corresponding to seven colors of C (cyan), M (magenta), Y (yellow), LC (light cyan), LM (light magenta), G (gray), and K (black). . The number of colors and the number of print heads are not limited to seven. As the ink jet method, a method using a heating element, a method using a piezo element, a method using an electrostatic element, a method using a MEMS (Micro Electro Mechanical System) element, or the like can be adopted. Each color ink is supplied from an ink tank (not shown) to the print head 14 via an ink tube. In the printing unit 4, the print head 14 can move in the direction of retracting from the sheet S. Thereby, the interval of the print head 14 with respect to the sheet S is adjusted.

  The inspection unit 5 optically reads an inspection pattern or image printed on the sheet S by the printing unit 4 using a scanner, and inspects the nozzle state of the print head 14, the conveyance state of the sheet S, the image position, and the like to obtain an image. This is a unit for determining whether printing has been performed correctly. The scanner includes a charge-coupled device (CCD) image sensor and a complementary metal oxide semiconductor (CMOS) image sensor.

  The cutter unit 6 is a unit including a mechanical cutter that cuts the printed sheet S into a predetermined length. The cutter unit 6 also includes a plurality of conveyance rollers for sending the sheet S to the next process. A trash can 17 is provided in the vicinity of the cutter unit 6. The trash box 17 accommodates small sheet pieces that are cut off by the cutter unit 6 and discharged as trash. The cutter unit 6 is provided with a sorting mechanism for discharging the cut sheet S to the trash box 17 or shifting it to the original conveyance path.

  The information recording unit 7 is a unit that records print information (unique information) such as a print serial number and date in a non-print area of the cut sheet S. Recording is performed by printing characters and codes using an inkjet method, a thermal transfer method, or the like. A sensor 23 that detects the leading edge of the cut sheet is provided on the upstream side in the conveyance direction of the sheet S of the information recording unit 7 and on the downstream side of the cutter unit 6. That is, the sensor 23 detects the leading edge of the sheet between the recording position by the cutter unit 6 and the information recording unit 7, and the timing at which the information recording unit 7 records information is controlled based on the detection timing of the sensor 23. .

  The drying unit 8 is a unit for heating the sheet printed by the printing unit 4 and drying the applied ink in a short time. Inside the drying unit 8, hot air is applied to the passing sheet S from at least the lower side (the side opposite to the ink application surface by the printing unit 4) to dry the ink application surface. The drying method is not limited to the method of applying hot air, and may be a method of irradiating the surface of the sheet S with electromagnetic waves (such as ultraviolet rays and infrared rays).

  The sheet conveyance path from the sheet supply unit 1 to the drying unit 8 is referred to as a first path. The first path has a U-turn shape between the printing unit 4 and the drying unit 8, and the cutter unit 6 is located in the middle of the U-turn shape.

  The reversing unit 9 is a unit for temporarily winding the continuous sheet S on which the front surface printing is completed when performing double-sided printing, and reversing the front and back, and is a sheet winding device. The reversing unit 9 is for supplying the sheet that has passed through the drying unit 8 to the printing unit 4 again, and is a path (referred to as a second path) from the drying unit 8 through the decurling unit 2 to the printing unit 4. It is provided on the way. The reversing unit 9 includes a winding rotary body that rotates to wind up and store the sheet S. The continuous sheet S that has been printed on the surface and has not been cut is temporarily wound and accommodated in the winding rotary member. When the winding is completed, the winding rotary member rotates in the reverse direction, and the wound sheet is supplied to the decurling unit 2 and sent to the printing unit 4. Since the sheet S is reversed, the printing unit 4 can print on the back side. More specific operation of duplex printing will be described later.

  The discharge conveyance unit 10 is a unit for conveying the sheet S cut by the cutter unit 6 and dried by the drying unit 8 and delivering the sheet S to the sorter unit 11. The discharge conveyance unit 10 is provided in a route (referred to as a third route) different from the second route in which the reversing unit 9 is provided. In order to selectively guide the sheet S conveyed on the first path to either the second path or the third path, a path switching mechanism having a movable flapper is provided at a branch position of the path.

  The sorter unit 11 and the discharge unit 12 are provided on the side of the sheet supply unit 1 and at the end of the third path. The sorter unit 11 is a unit for sorting the printed sheets S for each group as necessary. The sorted sheets S are discharged to the discharge unit 12 including a plurality of trays. As described above, the third path passes under the sheet supply unit 1 and has a layout in which the sheet S is discharged on the opposite side of the print unit 4 and the drying unit 8 with the sheet supply unit 1 interposed therebetween.

  The control unit 13 is a unit that controls each unit of the entire printing apparatus 31. The control unit 13 includes a CPU, a storage device, a controller including various control units, an external interface, and an operation unit 15 that is input and output by a user. The operation of the printing device 31 is controlled based on a command from a host device 16 such as a controller or a host computer connected to the controller via an external interface.

  FIG. 2 is a block diagram showing the concept of the control unit 13. The controller included in the control unit 13 (range surrounded by a broken line) includes a CPU 201, a ROM 202, a RAM 203, an HDD 204, an image processing unit 207, an engine control unit 208, and an individual unit control unit 209. The CPU 201 (central processing unit) controls the operation of each unit of the printing apparatus 31 in an integrated manner. The ROM 202 stores programs to be executed by the CPU 201 and fixed data necessary for various operations of the printing apparatus 31. The RAM 203 is used as a work area for the CPU 201, used as a temporary storage area for various received data, and stores various setting data. The HDD 204 (hard disk) can store and read programs executed by the CPU 201, print data, and setting information necessary for various operations of the printing apparatus 31. The operation unit 15 is an input / output interface with a user, and includes an input unit such as a hard key or a touch panel, and an output unit such as a display or a sound generator for presenting information.

  A dedicated processing unit is provided for units that require high-speed data processing. The image processing unit 207 performs image processing of print data handled by the printing apparatus 31. The color space (for example, YCbCr) of the input image data is converted into a standard RGB color space (for example, sRGB). Various image processing such as resolution conversion, image analysis, and image correction is performed on the image data as necessary. Print data obtained by these image processes is stored in the RAM 203 or the HDD 204. The engine control unit 208 performs drive control of the print head 14 of the print unit 4 according to print data based on a control command received from the CPU 201 or the like. The engine control unit 208 also controls the transport mechanism of each unit in the printing apparatus. The individual unit control unit 209 includes a sheet supply unit 1, a decurling unit 2, a skew correction unit 3, an inspection unit 5, a cutter unit 6, an information recording unit 7, a drying unit 8, a reversing unit 9, a discharge conveyance unit 10, and a sorter unit. 11 and a sub-controller for individually controlling each unit of the discharge unit 12. The individual unit control unit 209 controls the operation of each unit based on a command from the CPU 201. The external interface 205 is an interface (I / F) for connecting the controller to the host device 16 and is a local I / F or a network I / F. The above components are connected by the system bus 210.

  The host device 16 is a device serving as a supply source of image data for causing the printing device 31 to perform printing. The host device 16 may be a general-purpose or dedicated computer, or a dedicated image device such as an image capture having an image reader unit, a digital camera, or a photo storage. When the host device 16 is a computer, an OS, application software for generating image data, and a printing device driver for the printing device are installed in a storage device included in the computer. Note that it is not essential to implement all of the above processing by software, and a part or all of the processing may be realized by hardware.

  Next, the basic operation during printing will be described. Since the printing operation differs between the single-sided printing mode and the double-sided printing mode, each will be described.

<Single-sided print mode>
FIG. 3A is a diagram for explaining the operation in the single-sided print mode. A flow of transporting the sheet S printed on the sheet S supplied from the sheet supply unit 1 and discharged to the discharge unit 12 is indicated by a bold line. The sheet S supplied from the sheet supply unit 1 and processed by the decurling unit 2 and the skew feeding correction unit 3 is printed on the front surface (first surface) by the printing unit 4. On a long continuous sheet S, an image having a predetermined unit length in the conveyance direction (referred to as a unit image) is sequentially printed to form a plurality of images side by side. The printed sheet S passes through the inspection unit 5 and is cut for each unit image in the cutter unit 6. The cut cut sheet S is recorded with print information on the back surface of the sheet S by the information recording unit 7 as necessary. Then, the cut sheets S are conveyed one by one to the drying unit 8 and dried. Thereafter, the sheet is sequentially discharged and stacked on the discharge unit 12 of the sorter unit 11 via the discharge conveyance unit 10. On the other hand, the sheet S left on the side of the print unit 4 by cutting the last unit image is sent back to the sheet supply unit 1, and the sheet is wound on the roll R1 or R2. At the time of feeding, the decurling force in the decurling unit 2 is adjusted to be small, and the print head 14 is retracted from the sheet S.

In this way, in single-sided printing, the sheet S is processed through the first path and the third path, and does not pass through the second path. In summary, in the single-sided print mode, the following sequences (1) to (6) are executed under the control of the controller of the control unit 13.
(1) The sheet S is sent out from the sheet supply unit 1 and supplied to the printing unit 4;
(2) The unit 4 repeats printing of unit images on the first surface of the supplied sheet S;
(3) Repeat cutting of the sheet S by the cutter unit 6 for each unit image printed on the first surface;
(4) The sheet S cut for each unit image is passed through the drying unit 8 one by one;
(5) The sheets S that have passed through the drying unit 8 one by one are discharged to the discharge unit 12 through the third path;
(6) The last unit image is cut and the sheet S left on the print unit 4 side is sent back to the sheet supply unit 1.

<Double-sided print mode>
FIG. 3B is a diagram for explaining the operation in the duplex printing mode. In duplex printing, a back surface (second surface) print sequence is executed after a front surface (first surface) print sequence. In the first front surface print sequence, the operation in each unit from the sheet supply unit 1 to the inspection unit 5 is the same as the one-sided printing operation described above. In the cutter unit 6, the cutting operation is not performed, and the continuous sheet S is conveyed to the drying unit 8. After the surface ink is dried by the drying unit 8, the sheet is guided not to the path on the discharge conveyance unit 10 (third path) but to the path on the reversing unit 9 (second path). In the second path, the sheet S is wound around the winding rotary body of the reversing unit 9 that rotates in the forward direction (counterclockwise direction in the drawing). When all the scheduled printing on the front surface is completed in the printing unit 4, the rear end of the printing area of the continuous sheet S is cut by the cutter unit 6. The continuous sheet S on the downstream side (printed side) in the transport direction is wound up to the sheet rear end (cutting position) by the reversing unit 9 through the drying unit 8 with respect to the cutting position. On the other hand, the continuous sheet S left on the upstream side in the conveyance direction (the print unit 4 side) with respect to the winding position at the reversing unit 9 does not leave the sheet tip (cutting position) in the decurling unit 2. Then, the sheet S is sent back to the sheet supply unit 1, and the sheet S is wound around the roll R1 or R2. By this feed back (back feed), collision with a sheet supplied again in the following back surface printing sequence is avoided. As will be described later, at the time of feeding, the decurling force at the decurling unit 2 is adjusted to be small, and the print head 14 is retracted from the sheet.

  After the above-described front surface print sequence, the back surface print sequence is switched. The winding rotary body of the reversing unit 9 rotates in the opposite direction (clockwise direction in the drawing) to that during winding. The end portion of the wound sheet S (the trailing end of the sheet at the time of winding becomes the leading end of the sheet at the time of feeding) is fed into the decurling unit 2 along the path of the broken line in the drawing. In the decurling unit 2, the curl imparted by the winding rotary member is corrected. That is, the decurling unit 2 is provided between the sheet supply unit 1 and the printing unit 4 in the first path and between the reversing unit 9 and the printing unit 4 in the second path, and functions as a decal in any path. It is a common unit. The sheet S in which the front and back sides of the sheet S are reversed is sent to the printing unit 4 through the skew correction unit 3, and printing is performed on the back surface of the sheet S. The printed sheet passes through the inspection unit 5 and is cut into predetermined unit lengths set in advance in the cutter unit 6. Since the cut sheet is printed on both sides, recording by the information recording unit 7 is not performed. Cut sheets are conveyed one by one to the drying unit 8, and sequentially discharged and stacked on the discharge unit 12 of the sorter unit 11 via the discharge conveyance unit 10.

As described above, in duplex printing, a sheet passes through the first path, the second path, the first path, and the third path in this order. In summary, in the double-sided print mode, the following sequences (1) to (11) are executed under the control of the controller of the control unit 13.
(1) The sheet S is sent out from the sheet supply unit 1 and supplied to the printing unit 4;
(2) The unit 4 repeats printing of unit images on the first surface of the supplied sheet S;
(3) The sheet S printed on the first surface is passed through the drying unit 8;
(4) The sheet S that has passed through the drying unit 8 is guided to the second path, and is wound on the winding rotary member of the reversing unit 9;
(5) After repeated printing on the first surface, the sheet is cut by the cutter unit 6 behind the last printed unit image;
(6) The sheet S is wound around the winding rotary body until the trailing end of the cut sheet S passes through the drying unit 8 and reaches the winding rotary body, and the sheet left on the print unit 4 side by cutting is removed. Send back to the supply 1;
(7) When the winding is completed, the winding rotary member is rotated in the reverse direction, and the sheet S is supplied again to the printing unit 4 from the second path;
(8) Repeat printing of unit images by the printing unit 4 on the second surface of the sheet S supplied from the second path;
(9) Repeat cutting of the sheet S by the cutter unit 6 for each unit image printed on the second surface;
(10) The sheets S cut for each unit image are passed through the drying unit 8 one by one;
(11) The sheets S that have passed through the drying unit 8 one by one are discharged to the discharge unit 12 through the third path.

  Next, the reversing unit 9 which is a characteristic part of the printing apparatus having the above-described configuration will be described in more detail.

  FIG. 4 is a cross-sectional view showing the configuration of the main part centering on the winding rotary member of the reversing part 9. In addition, the line shown with a broken line is the sheet | seat S wound up by the winding rotary body 104. FIG. From the downstream side of the drying unit 8, a conveyance unit (second conveyance unit) 174, a plurality of driven rollers 170 located in the U-turn portion of the second path, a conveyance roller pair (first roller) including the conveyance roller 102 and the pinch roller 103 ) 151 and the winding rotary body 104 are provided in this order.

  The winding rotary body 104 has a hollow cylindrical shape with at least a part inside. The sheet S is introduced into or discharged from the winding rotary member 104 by the conveying roller pair 151.

  The pinch roller 103 is provided with a pressing force control cam 172 and a pinch roller spring 171 as pressing force control means, and the operating length of the pinch roller spring 171 is changed by rotating the pressing force control cam 172. Can do. The pinch roller 103 is pushed by the pinch roller spring 171 through the pinch roller holder 173. As a result, the pressing force of the pinch roller 103 to the conveying roller 102 can be changed.

  An edge sensor 101 is provided in front of the conveyance roller 102. The edge sensor 101 detects the leading edge or trailing edge of the sheet S introduced into the reversing unit 9.

  In the vicinity of the surface (winding surface) of the winding rotary body 104, a holding roller pair 150 including a holding roller 108 and a pinch roller 107 that can nip and rotate the leading edge of the sheet S is provided. The pinch roller 107 is energized with a predetermined force with respect to the holding roller 108 and is driven to rotate. The sheet insertion portion 160 is formed in a slit shape in a part of the surface of the winding rotary body 104, and the leading end of the introduced sheet S is inserted therein. The leading edge of the inserted sheet S is nipped and held by a holding roller pair 150. Further, the inserted sheet S can be drawn into the internal space of the winding rotary body 104 by rotating the holding roller pair 150. That is, the holding roller pair 150 has a function as a clamper that holds the sheet S and a function as a conveyance roller that conveys the sheet S. The flag 105 is a member serving as a reference for detecting the origin (initial position) of the rotation position of the winding rotary body 104. The rotation sensor 106 is a sensor that detects the rotational position of the winding rotary body 104. In FIG. 4, the position of the winding rotary body 104 is at the initial position, and the sheet insertion portion 160 faces the sheet S introduction path.

  A first drive mechanism that rotationally drives the winding rotator 104 is provided on one side surface of the winding rotator 104. In addition, a second drive mechanism that rotationally drives at least one roller (holding roller 108) constituting the holding roller pair 150 is provided on the other side surface side of the winding rotary body 104.

  FIG. 5 is a perspective view showing the configuration of the drive mechanism of the winding rotary body 104. In FIG. 5A, a first drive mechanism is provided on the front side of the winding rotary body 104 in the drawing, and a second drive mechanism is provided on the back side. FIG. 5B is a view as viewed from the opposite side to FIG. 5A, and the second drive mechanism is on the front side of the winding rotary body 104 in the drawing, and the first drive mechanism is on the back side. Is provided. FIG. 6 shows a configuration of a main part of the second drive mechanism. FIG. 6A is a perspective view showing a hollow internal configuration with the winding surface of the winding rotary body 104 removed, and FIG. 6B is a cross-sectional view showing gear coupling.

  First, the first drive mechanism 130 will be described. The first drive mechanism 130 includes a first drive motor 109 and a first gear train that transmits the driving force of the first drive motor 109 to the rotation shaft of the winding rotary body 104. The first gear train includes a motor gear 109a, a gear 110, a clutch unit (slip portion) 111, a gear 112, a gear 113, and a drum gear 114. The clutch unit 111 includes an input gear 111a, an output gear 111b, and a clutch portion 111c. The clutch unit 111 can manage drive tension and sheet tension during sheet winding. In the clutch unit 111, when a predetermined torque is generated, the output gear 111b slips with respect to the input gear 111a. Therefore, the driving force from the first drive motor 109 is not always transmitted to the 100% winding rotary body 104. The rotation of the first drive motor 109 is decelerated at a predetermined gear ratio by the first gear train and transmitted to the drum gear 114. The drum gear 114 is fixed to a rotation shaft 104a that is the center of rotation of the winding rotary body 104, and the drum gear 114 and the winding rotary body 104 rotate together.

  When the sheet is wound, the rotation speed of the winding rotator 104 (peripheral speed of the outer periphery of the wound roll-shaped sheet) is the transport of the sheet S introduced into the winding rotator 104 by the transport unit 174 and the transport roller pair 151. The rotation speed is set so as to be larger than the speed. Therefore, torque is generated in the clutch unit 111. When this torque reaches a predetermined value, the output gear 111b slips with respect to the input gear 111a, and this speed difference is absorbed. Therefore, as a result, the rotation speed of the take-up rotating body 104 becomes a speed that is in accordance with the conveyance unit 174 and the conveyance roller pair 151. In other words, the sheet conveyance speed during sheet winding is mainly determined by the conveyance unit 174 and the conveyance roller pair 151.

  Further, by setting the rotation speed as described above, the winding rotary member 104 is transported while stretching the sheet by the plurality of driven rollers 170 of the U-turn portion located in the second path. Therefore, a brake force is applied to the winding rotary member 104 via the seat due to the slip of the clutch unit 111, and a predetermined tension is applied to the seat S. The winding rotary member 104 rotates while being wound from the sheet S with a predetermined tension, and winds up the sheet S.

  Similarly, at the time of sheet feeding, the rotation speed is set so that the rotation speed of the winding rotary body 104 is smaller than the conveyance speed of the sheet S by the conveyance roller pair 151. Therefore, torque is generated in the clutch unit 111. When this torque reaches a predetermined value, the output gear 111b slips with respect to the input gear 111a, and this speed difference is absorbed. Therefore, as a result, the rotation speed of the winding rotary body 104 becomes a speed that is equal to the conveyance roller pair 151. In other words, the sheet conveyance speed at the time of sheet feeding is mainly determined by the conveyance roller pair 151.

  Next, the second drive mechanism 140 will be described. The second drive mechanism 140 includes a second drive motor 115 and a second gear train that transmits the rotation of the second drive motor 115 to the rotation shaft of the holding roller 108. The second gear train includes a motor gear 115a, a clutch unit 117, a gear 118, a transmission gear 119, a gear 120, and a roller gear 121. The clutch unit 117 includes an input gear 117a, an output gear 117b, and a clutch portion 117c, and can switch between transmission and disconnection of rotational force. The rotation of the second drive motor 115 is decelerated at a predetermined gear ratio by the second gear train and transmitted to the roller gear 121. The roller gear 121 is fixed to a rotation shaft that is the center of rotation of the holding roller 108, and the roller gear 121 and the holding roller 108 rotate together. The transmission gear 119 has an integrated input gear 119a and output gear 119b. Both the input gear 119a and the output gear 119b have the same rotation center as the rotation shaft 104a of the winding rotary body 104, and rotate idle with respect to the rotation shaft 104a. A lock gear 125 is fixed to the end of the rotating shaft 104a. The lock gear 125 and the transmission gear 119 are connected by a clutch unit 124 that can switch between transmission and disconnection of force. The clutch unit 124 includes an input gear 124a that meshes with the lock gear 125 and an output gear 124b that meshes with the input gear 119a. That is, two of the gear 118 and the output gear 124b mesh with the input gear 119a.

  Note that both ends of the rotating shaft of the pinch roller 107 are rotatably supported by a pinch roller bearing 123. The pinch roller bearing 123 is biased downward by a pinch roller spring 122, whereby the pinch roller 107 is biased against the holding roller 108.

  In the above configuration, when the holding roller 108 is rotated by the second drive motor 115, the clutch unit 117 is connected and the clutch unit 124 is disconnected. When the second drive motor 115 is driven in this state, the rotation of the second drive motor 115 is transmitted to the roller gear 121 via the gear 120, and the holding roller 108 rotates (autorotates). In this example, the holding roller 108 which is one roller constituting the holding roller pair 150 is driven by the second drive motor 115, but the side of the pinch roller 107 may be driven. Alternatively, both the holding roller 108 and the pinch roller 107 may be driven by the second drive motor 115.

  At the time of winding the sheet S by the winding rotary body 104, it is necessary to make the holding roller 108 not rotate (the locked state with respect to the winding rotary body 104) while the leading end of the sheet S is nipped by the holding roller pair 150. is there. In this case, the clutch unit 117 is disconnected and the rotational force from the second drive motor 115 is disconnected, and the clutch unit 124 is connected. Then, the transmission gear 119 rotates with the lock gear 125 at a constant speed, that is, the transmission gear 119 does not rotate relative to the rotation shaft 104a (a state that can be regarded as a substantially integrated object). Along with this, the gear 120 and the holding roller 108 are also not rotated relative to the take-up rotating body 104 (a state that does not rotate). When the first drive motor 109 is driven in this state, the rotation of the first drive motor 109 is transmitted to the drum gear 114, and the take-up rotating body 104 rotates to take up the sheet S. At this time, the holding roller 108 is stationary without rotating.

  Next, a specific operation of the reversing unit 9 that is a sheet winding device in double-sided printing will be described. FIG. 7 is a flowchart showing an operation sequence when the sheet is wound on the winding rotary member of the reversing unit 9, and FIG. 8 is a diagram for explaining the movement at that time.

  First, the pressing force control cam 172 sets the pinch roller 102 to the first pressing force (S11). The first pressing force is set to be a low pressing force such that the sheet is conveyed while slipping by the conveying roller pair 151 when the winding is performed.

  Next, when the front surface printing is started in the double-sided printing mode, the winding rotator 104 is rotated so that the orientation of the winding rotator 104 is stationary at the initial position as shown in FIG. 4 (S12). At the initial position, the sheet insertion portion 160 faces the introduction path of the sheet S, and the sheet S introduced into the winding rotary body 104 is smoothly inserted into the sheet insertion portion 160.

  The clutch unit 117 is connected and the clutch unit 124 is disconnected (S13). The holding roller 108 can rotate with respect to the winding rotary member 104.

  The conveying motor of the conveying roller 102 is driven so that the conveying roller 102 rotates in the forward direction (sheet winding direction), and the second driving motor 115 is driven in the forward direction by the holding roller 108 (the sheet is drawn into the winding rotary body). (S14).

  When the leading edge of the sheet S is detected by the edge sensor 101 and detected, the sheet S is conveyed until the leading edge of the sheet S reaches a position that passes through the nip portion of the holding roller pair 150 (see FIG. 8A). (State) (S15).

  The clutch unit 117 is disconnected and the clutch unit 124 is connected (S16). The holding roller 108 is stationary with respect to the winding rotary member 104.

  The first drive motor 109 is driven to rotate in the forward direction (sheet winding direction), and winding of the sheet S onto the winding rotary body 104 is started (state in FIG. 8B) (S17).

  After a predetermined time from the start of the rotation of the first drive motor 109, the rotation of the second drive motor 115 is stopped. Subsequently, the first drive motor 109 continues to rotate and continues to wind the sheet (S18). As the length of the wound sheet increases, the thickness of the sheet wound on the winding surface of the winding rotary body 104 also increases (state shown in FIG. 8C).

  Since the speed at which the sheet S is introduced into the reversing unit 9 which is a sheet winding apparatus is constant, the winding speed of the sheet S needs to be kept constant accordingly. Therefore, at the time of winding the sheet, the rotation speed of the first drive motor 109 is set in advance so that the winding speed of the winding rotary body 104 is larger than the conveying speed of the sheet S by the conveying unit 174 and the conveying roller pair 151. To do. Since the output gear 111b slips with respect to the input gear 111a in the clutch unit 111, the rotation speed of the winding rotary member 104 is equal to the conveyance speed of the conveyance unit 174 and the conveyance roller pair 151 even if the sheet thickness increases. It will keep a constant speed.

  When winding is performed, the pressing force control cam 172 sets a low pressing force (first pressing force) such that the sheet S is conveyed while slipping by the conveying roller pair 151. Therefore, the take-up rotating body 104 transports the sheet S while stretching it with the plurality of driven rollers 170 in the U-turn portion of the second transport path. This makes it possible to stably apply tension to the sheet S and to perform winding without sagging.

  When all the printing on the surface of the sheet S is completed, the trailing edge of the sheet is cut with a cutter, and the rewinding unit 9 continues to wind.

  The edge sensor 101 detects the trailing edge of the introduced sheet S (the trailing edge of the surface printed and cut sheet) (S19). When the trailing edge of the sheet S passes the detection position of the edge sensor 101, the signal output of the edge sensor 101 changes from “ON: sheet present” to “OFF: sheet absent”. The presence or absence of the sheet S is detected to detect the rear end of the sheet S. When the trailing edge of the sheet S is detected, the process proceeds to the next step.

  The rotation of the conveyance motor of the conveyance roller 102 is stopped, and the rotation of the first drive motor 109 is also stopped (S20). The position where the introduced sheet S is stopped is a position where the trailing edge of the sheet S detected by the edge sensor 101 is maintained by the conveying roller pair 151 without leaving the nip position. This is for facilitating the subsequent sheet feeding. In this way, the sheet winding operation for front side printing is completed.

  Subsequent to the above winding operation, backside printing is performed. FIG. 9 is a flowchart showing an operation sequence when the sheet is sent out from the winding rotary member, and FIG. 10 is a diagram for explaining the state of the apparatus at that time. A line indicated by a broken line is the sheet S sent out from the winding rotary body 104.

  The pressing force control cam 172 sets the pinch roller 102 to the second pressing force (S21). The second pressing force is larger than the first pressing force, and when the conveyance roller pair 151 performs the conveyance of the sheet S, the inertia of the winding rotary member 104 and the wound sheet, and the load, A high pressing force is set so that the sheet S does not slip by the conveying roller pair 151.

  The conveying motor of the conveying roller 102 is driven to rotate in the reverse direction (sheet feeding direction), and the first drive motor 109 is driven to rotate in the reverse direction (sheet feeding direction) (S22).

  When the feeding of the sheet S from the winding rotary body 104 is started, the edge sensor 101 detects the leading end of the sheet S to be fed out (the last end of the surface printed and cut sheet) (S23). When the leading edge of the sheet S passes the detection position by the edge sensor 101, the signal output of the edge sensor 101 changes from “OFF: no sheet” to “ON: sheet present”. The leading edge of the sheet S is detected by detecting the presence or absence of the sheet S. When the leading edge of the sheet S is detected, the process proceeds to the next step.

  Based on the detection by the edge sensor 101 (S23), the conveyance amount of the sheet S (the sheet length of the fed sheet) is counted, and the conveyance of the sheet S is continued until the count reaches a predetermined value (S24). The predetermined value is the sheet length of the sheet S that has been wound around the winding rotary body 104.

  Since the speed at which the sheet S is sent out toward the printing unit 4 by the conveying roller pair 151 is constant, it is necessary to keep the sending speed of the sheet S from the winding rotary body 104 constant accordingly. Therefore, when the sheet S is sent out, the rotation speed of the first drive motor 109 is set in advance so as to be lower than the conveyance speed of the sheet S conveyed by the conveyance roller pair 151. Since the output gear 111b slips with respect to the input gear 111a in the clutch unit 111, even if the thickness of the sheet S wound around the winding rotary body 104 is reduced, the rotational speed of the winding rotary body 104 is A constant speed is maintained in accordance with the conveying roller pair 151. That is, the winding rotary body 104 rotates following the conveyance of the sheet S by the conveyance roller pair 151.

  At the timing immediately before the trailing edge of the sheet S comes out of the nip of the holding roller pair 150, the clutch unit 117 is disconnected and the clutch unit 124 is disconnected (S25). Since both clutches are disengaged, the holding roller 108 is free to rotate from the second drive motor 115 and the winding rotary member 104. Therefore, the holding roller 108 and the pinch roller 107 are driven by the sheet S to be pulled out, and the trailing edge of the sheet S can be removed from the nip of the holding roller pair 150 with a small resistance.

  The trailing edge of the sheet S sent out is detected by the edge sensor 101 (S26). When the trailing edge of the sheet S passes the sensor detection position by the edge sensor 101, the signal output of the edge sensor 101 changes from “ON: sheet present” to “OFF: sheet absent”. The rear end of the sheet S is detected by detecting the change in the presence or absence of the sheet. When the trailing edge of the sheet S is detected, the process proceeds to the next step.

  The rotation of the conveyance motor of the conveyance roller 102 is stopped, and the rotation of the first drive motor 109 is also stopped (S27). Thus, the sheet S feeding operation for backside printing is completed. In this way, the fed sheet S is printed on the back side to complete double-sided printing.

  As described above, when winding is performed, the pressing force control cam 172 sets a low pressing force (first pressing force) such that the sheet S is conveyed while slipping by the conveying roller pair 151. Has been. Therefore, the take-up rotating body 104 conveys the sheet while stretching the sheet by the plurality of driven rollers 170 in the U-turn portion of the conveyance path. This makes it possible to stably apply tension to the sheet, and to wind the sheet without sagging.

  Further, when the sheet is sent out from the winding rotary body, the pressing force control cam 172 is set so that the pinch roller 102 becomes the second pressing force. This second pressing force is greater than the first pressing force. The second pressing force is also applied to the inertia and load of the take-up rotating body 104 and the wound sheet when the transport roller pair 151 is transporting the sheet S for backside printing. The roller pair 151 is set so that no slip of the sheet S occurs. For this reason, the inertia of the sheet wound around the winding rotary body 104 and the winding rotary body 4 when the sheet S is sent out disturbs the conveyance of the sheet S to the downstream unit (decal section, skew feeding correction section). Can be prevented.

4 Print unit 9 Sheet winding unit (sheet winding device)
31 Printing Device 104 Winding Rotator 111 Clutch Unit (Slip)
151 Conveying roller pair (first conveying means)
171 Pinch roller spring (pressing control means)
172 Pressing force control cam (pressing control means)
174 Conveying section (second conveying means)

Claims (11)

In the sheet winding device,
A winding rotary body for winding the sheet;
First conveying means for conveying the sheet to the winding rotary body or conveying the sheet from the winding rotary body,
The sheet winding apparatus, wherein when the sheet is sent out from the winding rotating body by the first conveying unit, the winding rotating body rotates following the conveyance of the sheet by the first conveying unit. A driving mechanism for driving the winding rotary body, the driving mechanism having a slip portion where a driving force is not transmitted to the winding rotary body when a predetermined torque is applied;
The drive mechanism is configured such that when the sheet is sent out from the take-up rotating body, the rotation speed of the take-up rotating body is adjusted so that the predetermined torque is generated in the slip portion. The sheet winding apparatus according to claim 1, wherein the winding rotating body is driven with the driving force that is smaller than a conveyance speed. Having second conveying means for conveying the sheet to the first conveying means;
The drive mechanism is configured such that when the sheet is wound by the winding rotator, the rotational speed of the winding rotator is adjusted by the second conveying unit so that the predetermined torque is generated in the slip portion. The sheet winding apparatus according to claim 2, wherein the winding rotary body is driven by the driving force that is greater than a conveyance speed. A pressing force control unit that changes the pressing force of the first conveying unit to the sheet to a first pressing force or a second pressing force that is larger than the first pressing force;
The pressing force control means sets the first pressing force when the first conveying means conveys the sheet to the winding rotary body, and the first conveying means removes the sheet from the winding rotary body. The sheet winding apparatus according to claim 3, wherein the second pressing force is used when the sheet is conveyed.   At the time of winding the sheet by the winding rotary body, the sheet is conveyed while slipping in the first conveying means, and at the time of feeding the sheet from the winding rotary body, at the first conveying means The sheet winding apparatus according to claim 4, wherein the sheet is conveyed without slipping.   6. The driven roller according to claim 3, wherein a plurality of driven rollers for applying tension to the sheet are provided between the first conveying unit and the second conveying unit. 7. Sheet winding device.   The sheet winding apparatus according to any one of claims 2 to 6, wherein the slip portion is a clutch unit.   The sheet according to any one of claims 1 to 7, wherein a conveyance path of the sheet is different between when the sheet is wound by the winding rotator and when the sheet is sent out from the winding rotator. Winding device. In the sheet processing apparatus having the sheet winding apparatus according to any one of claims 1 to 8,
A sheet supply unit for supplying the sheet;
A processing unit that performs a predetermined process on the sheet supplied from the sheet supply unit,
The sheet winding apparatus is a sheet processing apparatus that winds the sheet processed by the processing unit.   The sheet processing apparatus according to claim 9, wherein the predetermined processing includes at least one of printing, recording, processing, application, irradiation, reading, and inspection of the sheet. In the printing apparatus which has a sheet winding apparatus of any one of Claims 1-8, and can perform double-sided printing,
A sheet supply unit for holding and supplying continuous sheets;
A print unit that performs printing on the sheet supplied from the sheet supply unit,
The sheet winding device winds the sheet that has been printed on the first surface by the printing unit, and then rotates the winding rotating body in the reverse direction to print on the second surface of the sheet by the printing unit. The printing apparatus sends out the sheet to the printing unit so that the printing is performed.

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