JP2017178484A - Medium transport device and printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a medium transport device guiding a medium in a state of the medium being held by a roller pair in a direction intersecting with a tangential direction in a nip position, the medium transport device making transportation of the medium smooth, and a printer having the medium transport device.SOLUTION: A medium transport device comprises: an intermediate roller 30 (drive roller); a second driven roller 32 holding a medium together with the intermediate roller 30; and a guide member 55 disposed closer to a downstream side than a nip position of the medium by a roller pair 69 (both rollers 30 and 32) in a transportation path. The guide member 55 guides the medium transported closer to the downstream side than the nip position by rotation of the roller pair 69 in a direction intersecting with a tangential direction in the nip position in a state of holding the medium, and has a non-contact portion 73 with which the medium transported in association with the rotation of the roller pair is not brought into contact at a portion facing the nip position in a direction along a rotation axis of each roller.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a medium conveying apparatus for conveying a medium and a printing apparatus having the medium conveying apparatus.

  2. Description of the Related Art Conventionally, there is known a medium transport device that guides a medium sandwiched between a pair of rollers in a direction intersecting a tangential direction at the nip portion (see FIG. 1 of Patent Document 1). In the technique of Patent Document 1, a medium sandwiched between a large-diameter roller (inverted roller in the same document) and a small-diameter roller (intermediate roller in the same document) constituting a roller pair is obliquely below the horizontal direction by a guide member. Be guided to. In this case, the guide member guides the medium in a direction shifted from the tangential direction at the nip portion between the large diameter roller and the small diameter roller.

JP 2010-253754 A

  By the way, in such a medium transport device, when the roller pair rotates while sandwiching the medium, when the medium is guided in a direction intersecting the tangential direction at the nip portion, the medium transport may be hindered. is there. For example, such a trouble is likely to occur when the guide member guides the medium in a direction intersecting the tangential direction at the nip portion of the roller pair in the vicinity of the roller pair in the medium conveyance path.

  An object of the present invention is to facilitate the conveyance of a medium in a medium conveyance device that guides the medium in a direction intersecting a tangential direction at a nip portion while the medium is sandwiched by a pair of rollers.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
A medium conveying apparatus that solves the above problems includes a driving roller, a driven roller that sandwiches the medium together with the driving roller, and a guide that is disposed on the downstream side of the nip portion of the medium by the two rollers in the medium conveying path. The guide member has a direction intersecting a tangential direction at the nip portion with respect to the medium conveyed downstream from the nip portion when the rollers rotate while the medium is sandwiched. In a direction along the rotation axis of each roller, the portion facing the nip portion has a non-contact portion where the medium conveyed along with the rotation of the two rollers does not contact.

  Normally, when the medium is transported by rotating both rollers while being sandwiched between the driving roller and the driven roller, the portion of the medium that is sandwiched between the two rollers (clamping corresponding part) is downstream in the transport direction. The propulsive force (force that pushes the medium) acts. For this reason, when the frictional force between the front end portion and the guide member increases in a state where the front end portion of the medium is in contact with the guide member with respect to the portion sandwiched between the rollers, the medium Smooth conveyance of the air is hindered.

  In this regard, according to the above configuration, there is a non-contact portion where the medium does not come into contact with the nip portion of the guide member in the direction along the rotation axis of each roller, and the portion of the medium that is sandwiched between the two rollers ( Since the clamping support portion does not contact the guide member, a situation in which smooth conveyance of the medium is hindered is less likely to occur.

  In the medium conveying apparatus, the driving roller and the driven roller are configured to sandwich the medium so that a tangential direction at the nip portion is a downward gradient toward the downstream side in the medium conveying direction, and the guide The member has a contact surface with which the medium conveyed downstream with the rotation of both rollers contacts, and the non-contact portion configured with a recess or a through hole, and the medium is on the contact surface. It is preferably configured as a flap that slides and passes downstream in the conveying direction, and the contact surface is configured to intersect a surface along the tangential direction at the nip location.

  According to this configuration, the flap in which the medium to be conveyed contacts the contact surface in a sliding state is provided not only with the contact surface with which the medium contacts, but also with a non-contact portion where the medium does not contact at that time. For this reason, the portion of the transported medium that is sandwiched between the two rollers (the sandwiching-corresponding portion) passes through the position where the non-contact portion of the flap is provided and does not contact the contact surface, so the medium is transported smoothly. Is done.

  In the medium conveying apparatus, it is preferable that ribs extending along the conveying path are provided on both sides of the non-contact portion in the direction along the rotation axis of the driving roller in the guide member.

  According to this configuration, in the medium to be transported, both sides of the portion (that is, the sandwiching corresponding portion) that advances from the nip portion between the two rollers to the non-contact portion are lifted by the ribs so that the medium is curved, and The rigidity (difficulty of bending) can be increased.

  In the medium conveying apparatus, the guide member includes a pair of first ribs as the ribs, and a pair of second ribs arranged on the outer side in the direction along the rotation axis than the pair of first ribs. The distance between the first rib and the second rib is preferably longer than the distance between the pair of first ribs.

  According to this configuration, in the direction along the rotation axis, the medium has the outer portion hanging down from the first rib and the inner portion rising from the first rib with the first rib as a fulcrum. Accordingly, the medium is curved at a plurality of locations in the direction along the rotation axis, and the rigidity (difficulty in bending) in the transport direction can be increased.

In the medium transport apparatus, it is preferable that the top portion of the rib has an arc shape with a cross-section as viewed from the downstream side in the transport direction of the medium.
According to this configuration, the transport load when the medium transported downstream in the transport direction slides on the top of the rib is less than when the top of the rib has a flat shape that can come into surface contact with one surface of the medium. Is done.

In the medium conveying apparatus, it is preferable that the contact surface is a smooth surface.
According to this configuration, the transport load when the medium transported downstream in the transport direction contacts the contact surface in a sliding state is reduced as compared with the case where the contact surface is a non-smooth surface.

  In addition, a printing apparatus that solves the above-described problem includes the medium conveyance device having the above-described configuration and a printing unit that performs printing on the medium conveyed by the medium conveyance device. According to this configuration, the same effect as that of the above-described medium transport device can be enjoyed in the printing apparatus that performs printing on the medium.

FIG. FIG. The expanded sectional view of a multifunctional machine. 1 is a schematic cross-sectional view of a printing apparatus. 1 is a perspective view of a medium transport device according to an embodiment. The schematic cross section of a flap. The perspective view of the medium conveyance apparatus which concerns on a comparison. FIG. 8 is a schematic cross-sectional view taken along the line AA in FIG. 7, illustrating an operation of a medium conveyed by the medium conveying apparatus according to the comparison. 1 is a perspective view of a medium transport device according to an embodiment. FIG. 10 is a schematic cross-sectional view taken along line B-B in FIG. 9, illustrating an operation of a medium conveyed by the medium conveyance device according to the embodiment. FIG. 3 is a control block diagram in the printing apparatus. FIG. 5 is a schematic diagram illustrating a medium conveying operation. FIG. 5 is a schematic diagram illustrating a medium conveying operation. FIG. 5 is a schematic diagram illustrating a medium conveying operation. FIG. 5 is a schematic diagram illustrating a medium conveying operation. FIG. 5 is a schematic diagram illustrating a medium conveying operation. 6 is a timing chart of the operation of the printing apparatus. The perspective view of the other example of a guide member. The perspective view of the medium conveyance apparatus which concerns on other embodiment.

  Hereinafter, a multifunction peripheral including a printing apparatus will be described with reference to the drawings. In the following, the direction in which the printing unit moves during printing is referred to as “scanning direction X (width direction X)”, the direction in which the medium is conveyed at a location facing the printing unit is referred to as “conveying direction Y”, and the vertical direction is below The direction facing the side is defined as “gravity direction Z”. The transport direction of the medium at a place other than the part facing the printing unit in the transport path is simply “transport direction” without adding the symbol “Y”. In FIG. 3, the conveyance path of the medium is indicated by a one-dot chain line.

  As shown in FIG. 1, the multifunction machine 11 includes a printing device 12 having a printing function, an image reading device 13 having an image reading function, and an automatic document feeding device 14 for feeding a document to the image reading device 13. Prepare. The printing apparatus 12 includes a rectangular parallelepiped main body 15 and a main body lid 151 that can be opened and closed with respect to an upper surface opening (not shown) of the main body 15. The image reading device 13 pivots so as to be openable and closable with respect to a scanner main body 131 having a main body lid 151 with a reading mechanism built therein, and a document table 132 (see FIG. 2) constituting the upper surface of the scanner main body 131. And a lid 133 to be used. The automatic document feeder 14 is assembled on the lid 133 and can rotate in the opening / closing direction together with the lid 133. Along with the automatic document feeder 14, the lid 133 is movable between a closed position that covers the document table 132 and an open position where the document table 132 is exposed so that a document can be placed.

  Further, a concave gripping portion 152 is provided on the front side of the main body lid portion 151 (downstream side in the transport direction Y). The user grips and lifts the grip portion 152 upward, and rotates the main body lid portion 151 together with the image reading device 13 and the automatic document feeder 14 in the opening direction, so that the main body 15 is moved from the closed position shown in FIG. It is arranged at an open position (not shown) where the upper part of is opened. In a state where the main body lid 151 is in the open position, the printing mechanism in the housing 153 constituting the main body 15 is exposed, and the user replaces the ink container 39 (see FIG. 3) such as an ink cartridge and the medium jam. Maintenance work including removal work is possible.

  An automatic document feeder 14 shown in FIG. 1 includes a document table 141 on which a plurality of documents can be set, and a pair of document edges that are operated when positioning the document set on the document table 141 in the width direction. A guide 142 and a document support 143 capable of supporting a portion of the document protruding from the document placement table 141 are provided.

  A document discharge unit 144 is provided below the document table 141 to discharge the document fed by the automatic document feeder 14 after being scanned by the image reading device 13. The automatic document feeder 14 is disposed so as to face a pair of wall portions 145 disposed on both sides of the document placing table 141 in a direction crossing the document conveyance direction, and a discharge port of the document discharge portion 144. Side plate 146. Therefore, the document discharge portion 144 is surrounded by a pair of wall portions 145, a document placement table 141, and a side plate 146. The side plate 146 is provided with a recess 147 for allowing the user to check the document discharged to the document discharge unit 144. For this reason, it is possible to check the document discharged to the document discharge unit 144 through the recess 147 and to pick out the discharged document from the recess 147. The document support 143 may be a transparent member. By using a transparent member, even when a small-size document (for example, A6 size) is scanned using the automatic document feeder 14, the small-size document is copied through the document support 143 to the document discharge unit 144. Therefore, it is possible to prevent the document from being forgotten.

  As shown in FIG. 1, a rectangular plate-like operation panel 16 having a power button 17 and a touch panel type display unit 18 is provided on the upper front surface of the printing apparatus 12. In addition, the operation panel 16 is provided with an operation button 161, a power LED 162, a FAX reception LED 163, a print job reception LED 164, and an error notification LED 165. The operation button 161 functions as a cancel button during execution of printing, and functions as a copy button during standby for printing. When the operation button 161 is operated as a copy button, if a sensor (not shown) detects that a document is placed on the document placement table 141, the automatic document feeder 14 is driven to feed the document. Is scanned. On the other hand, when the sensor is not detected and no document is placed on the document placing table 141, the document placed on the document stand 132 is scanned. The main body 15 is provided with a USB slot lid 154 (not shown) on the side of the operation panel 16.

  A lower side of the operation panel 16 of the printing apparatus 12 is provided with a discharge port 19 for discharging the printed medium P and a slide-type discharge stacker 20 for receiving the medium P discharged from the discharge port 19. Yes. The discharge stacker 20 can be slid between the storage position shown in FIG. 1 and the unfolded position shown in FIG. 2 by manual operation. In addition, a cassette housing portion 155 including a housing space whose front surface is open and extends deeply is provided below the discharge stacker 20 in the housing 153 of the main body 15. In the cassette housing portion 155, upper and lower two-stage cassettes 21 and 22 capable of housing a plurality of media P are mounted in a state where they can be inserted and removed. A concave handle 156 (only one of which is shown in FIG. 1) is provided at the bottom of both sides of the main body 15 so that the user can hold the multifunction machine 11.

  Next, with reference to FIGS. 2 and 3, the internal configuration of the multifunction device 11, particularly the printing device 12, will be described. As shown in FIG. 2, a housing mechanism 153 accommodates a transport mechanism 24 that transports the medium P and a printing unit 25 that prints on the transported medium P. The transport mechanism 24 includes a feeding mechanism 26 that feeds the media P in the cassettes 21 and 22 to the printing unit 25 one by one. The feeding mechanism 26 is provided at a position corresponding to the insertion portion of each cassette 21, 22 in the main body 15 so as to be rotatable around a base end portion, and at a distal end portion of the arm member 27. Provided feeding roller 28 (pickup roller). In the following, when the feeding roller 28 is distinguished between the first cassette 21 side and the second cassette 22 side, the feeding roller 28 on the first cassette 21 side is denoted by reference numeral 281, and the second cassette 22 side The feeding roller 28 is indicated by reference numeral 282.

  Further, the cassettes 21 and 22 are provided with side edge guides 211 and 221 capable of positioning the medium P in the width direction by contacting side edges on both sides in the width direction of the medium P that is placed (set), and feeding of the medium P The rear end edge guides 212 and 222 that can be positioned against the upstream end (rear end) in the direction and the downstream end (front end) in the feeding direction of the medium P, and the front end is positioned. Possible claw portion (not shown). The medium P set in the cassettes 21 and 22 is held by the cassettes 21 and 22 when the tip of the medium P hits the claw portion. The claw portion is arranged at a position where it does not come into contact with the feeding roller 28 in the process of inserting the cassettes 21 and 22.

  The arm member 27 is urged by a spring (not shown) in the clockwise direction in FIG. In the process of inserting the cassettes 21 and 22 into the cassette housing portion 155, the arm member 27 is once rotated counterclockwise and then returned by its urging force, and the feeding roller 28 is out of the plurality of media P in the cassette 22. The topmost medium P is brought into contact with a predetermined urging force.

  As shown in FIG. 2, the back side of the cassette housing 155 in the main body 15 (right side in the figure) is inclined to a position facing the end of the cassettes 21 and 22 in the feeding direction (right direction in FIG. 2). Shaped separation plates 157 and 158 (separation wall portions) are respectively disposed. Even if a plurality of media P are fed out by the feeding roller 28, only the topmost sheet is separated and fed downstream in the feeding direction by sliding on the surfaces of the separation plates 157 and 158. The As described above, in this embodiment, the wall separation method is adopted as the separation method for separating the medium P into one sheet. Instead of the wall separation method, a roller separation method in which the medium P is separated into one sheet by passing between the pair of separation roller pairs may be employed.

  Further, as shown in FIG. 2, the feeding mechanism 26 includes transport paths 261 and 262 through which the medium P sent from the cassettes 21 and 22 is transported via the separation plates 157 and 158. The two conveyance paths 261 and 262 merge at a position above the separation plate 157 on the upper cassette 21 side. Hereinafter, the upper (first) cassette 21 is also referred to as a “first cassette 21”, and the lower (second) cassette 22 is also referred to as a “second cassette 22”.

  As shown in FIG. 2, the transport path 262 for transporting the medium P from the lower second cassette 22 located on the lower side of the upper first cassette 21 has a depth direction ( It is offset in the right direction in the figure. In the first cassette 21 and the second cassette 22, the front end portions 213 and 223 on the take-out side are flush with each other, but the rear end edge guide 222, the feeding roller 282, and the separation plate 158 corresponding to the second cassette 22 are The rear edge guide 212, the feed roller 281 and the separation plate 157 corresponding to the first cassette 21 are offset in the depth direction.

  As shown in FIG. 2, the feeding mechanism 26 includes a large-diameter intermediate roller 30 (driving roller) disposed obliquely above the junction 263 (see FIG. 3) of the two conveyance paths 261 and 262. The first driven roller 31 and the second driven roller 32 having a small diameter that come into contact with the outer peripheral surface of the intermediate roller 30 are provided. The medium P sent out from the selected one of the cassettes 21 and 22 passes through the corresponding one of the transport paths 261 and 262 to the joining unit 263, and the intermediate roller 30 is rotated by the rotation of the intermediate roller 30 from the joining unit 263. And the two driven rollers 31 and 32 are conveyed along a path along the outer periphery of the intermediate roller 30 in a state of being nipped (held). The medium P is sent out from the nip portion between the intermediate roller 30 and the second driven roller 32 toward the transport roller pair 33.

  Further, as shown in FIGS. 2 and 3, the medium P fed from the nip portion is guided to a position immediately downstream of the nip portion between the intermediate roller 30 and the second driven roller 32 in the transport direction. A guide member 55 for changing the feeding direction to the target direction is arranged. When the medium P is fed, the medium P fed from the nip portion between the intermediate roller 30 and the second driven roller 32 is guided to the downstream side in the substantially horizontal direction along the upper surface of the guide member 55, and the oblique ceiling After reaching the wall portion 56, it is conveyed along a diagonally downward surface along the oblique surface of the ceiling wall portion 56 while maintaining the upper limit height. Further, between the intermediate roller 30 and the transport roller pair 33, when the fed medium P is suspended from the guide member 55, the suspended portion is supported or dropped after being dropped from the guide member 55. A support member 57 that supports the rear end of the medium P is disposed.

  As shown in FIG. 3, the support member 57 has a concave curved surface in which the upstream portion in the transport direction on the upper surface supporting the medium P becomes lower toward the downstream side, and is located downstream of the concave curved portion in the transport direction. The portion is a flat surface extending substantially horizontally. Further, the support member 57 has a protruding end portion 57E at the downstream end portion in the transport direction. The protruding end portion 57E of the support member 57 includes a feeding path that forms a lower path that guides the medium P fed from the cassettes 21 and 22 to the pair of conveying rollers 33, and a conveying roller after printing on one surface (one surface). This is a branching point with the reverse passage 40 that guides the medium P, which is the object of double-sided printing reversely conveyed from the pair 33, to the intermediate roller 30.

  As shown in FIGS. 2 and 3, the transport mechanism 24 includes a transport roller pair 33 that transports the medium P fed from the feed mechanism 26 along a path that passes through a print area in which the printing unit 25 can print, and printing. The unit 25 includes a discharge roller pair 34 that discharges the printed medium P. At a position slightly upstream in the transport direction Y with respect to the transport roller pair 33, the elongated swinging member 58 is biased by a spring (not shown) in the counterclockwise direction in FIG. It is arranged in the state of standby posture leaning on. The swing member 58 includes a pressing rib 581 and a flap portion 582 that protrude downward. The holding rib 581 has a function of urging the rear end portion of the medium P downward and suppressing the lifting of the rear end portion of the medium P.

  Here, the protruding end that can come into contact with the medium P in the holding rib 581 is offset downward (gravitational direction Z) below the imaginary line that connects the nip position of the conveying roller pair 33 and the protruding end 57E of the support member 57. Is located. Ideally, the protruding end portion of the holding rib 581 is positioned on the imaginary line, but in consideration of manufacturing tolerances, in order to avoid inconvenience when it is shifted upward from the imaginary line, the swing member The protruding end of the pressing rib 581 is offset downward from the imaginary line in a state where the pressing rib 581 is biased downward by a spring load of 58.

  As shown in FIGS. 2 and 3, at a position between the transport roller pair 33 and the discharge roller pair 34 in the transport direction Y, a support base 35 that can support the medium P transported along the transport path. Is arranged. The transport roller pair 33 includes a transport drive roller 33A and a transport driven roller 33B that can be rotated by the rotation of the transport drive roller 33A. Further, the discharge roller pair 34 includes a discharge drive roller 34A and a discharge driven roller 34B that can be rotated by the rotation of the discharge drive roller 34A. Further, at a position between the discharge roller pair 34 and the support base 35 in the transport direction Y, a press roller 34C that presses the leading end portion of the medium P before being nipped by the discharge roller pair 34 from the upper side to prevent the lift. Is provided.

  As shown in FIGS. 2 and 3, the printing unit 25 is guided by a guide rail unit 37 and is reciprocated in the scanning direction X and held at a position above the support base 35. And a print head 38 attached to the side of the surface facing the support base 35. The carriage 36 is supported at two locations by a pair of upper and lower guide rails 37, for example, and is guided while being movable in the scanning direction X while being positioned in the transport direction Y and the gravity direction Z. A plurality of ink containers 39 having the same number as the ink color are mounted on the carriage 36. The print head 38 ejects the ink supplied from the ink container 39 mounted on the upper portion of the carriage 36 toward the medium P in the process of moving in the scanning direction X. For this reason, every time the medium P conveyed intermittently during printing stops, printing is performed line by line by the print head 38. The medium P after printing is discharged from the discharge port 19 by the rotation of the discharge roller pair 34 and the like, and is stacked on the discharge stacker 20. The discharge stacker 20 is unfolded to the state of use shown in FIG. 2 by rotating the tip portion after the user slides and protrudes from the storage position shown in FIG. 1 in the transport direction. The ink container 39 of the present embodiment is configured by an ink cartridge. However, the ink container 39 receives ink supplied from an ink tank attached to the inside or outside of the main body 15 through an ink tube (both not shown). May be an adapter capable of temporarily storing.

  In addition, the printing apparatus 12 of this example has a double-sided printing function. In the main body 15, the reverse path 40 (which reversely transports the medium P, which is transported in the transport direction Y and printed by the printing unit 25 on one side (one side), to the opposite side of the transport direction Y and leads to the junction unit 263. A switchback passage) is provided. The reversing passage 40 extends along a path passing through the lower side of the support member 57, and merges with the joining portion 263 of each of the transport passages 261 and 262. The medium P that has been printed on one surface (front surface) is reversely conveyed along the conveyance path F3 passing through the reversing path 40 to reach the merging unit 263, and from the merging unit 263, the intermediate roller 30 and the first driven roller. Introduced into the nip position with 31. Specifically, when the medium P passes through the reverse passage 40, the flap portion 582 guides the medium P at the time of switchback downward and guides it to the reverse passage 40. When the leading end of the medium P touches the flap portion 582 from the upstream side to the downstream side, the flap portion 582 rotates toward the downstream side in the transport direction Y, and the medium P is not regulated. On the other hand, when the medium P is switched back for printing on the other side (back side), even if the leading end of the medium P touches the flap portion 582 from the downstream side to the upstream side, it does not rotate and is switched back. The medium P is guided to the reverse passage 40.

  Then, the medium P is reversed in the process of being conveyed along the outer periphery of the intermediate roller 30, and the printing unit is turned in a state where the other surface passes through the conveying roller pair 33 and the other surface faces the print head 38. It is conveyed to 25. Then, printing on the other surface (back surface) of the medium P is performed by the printing unit 25, whereby double-sided printing is performed on the medium P. The medium P that has been printed on both sides is stacked on the discharge stacker 20.

  Further, as shown in FIG. 2, the image reading device 13 is a flat bed type scanner device, and a document table 132 provided with a document placing glass plate 134 and a lower position of the document placing glass plate 134 are set in a scanning direction X. And a scanner carriage 135 that can reciprocate along. As shown in FIGS. 2 and 3, a power supply unit 59 is provided in the main body 15 at a position above the transport path. The power supply unit 59 converts, for example, power from a commercial AC power source into direct current, and supplies power necessary for driving to the printing device 12, the image reading device 13, and the automatic document feeder 14.

  As shown in FIG. 3, a remaining amount sensor 201 for detecting the remaining amount of ink in the ink container 39 is provided in the main body 15 at a position downstream of the support base 35 in the transport direction Y. One remaining amount sensor 201 is arranged at a predetermined position in the scanning direction X. In the carriage 36, a plurality of detection holes 361 are opened in a line in the scanning direction X at positions that can face the remaining amount sensor 201. Ink from each ink container 39 is supplied to the print head 38 via the upper side of the hole 361 to be detected. When the hole 361 is positioned above the remaining amount sensor 201 as the carriage 36 moves in the scanning direction X, the remaining amount sensor 201 detects ink from the ink container 39 corresponding to the hole 361 through the hole 361. When there is ink, the detection state is set, and when the ink runs out, the detection state is set. The plurality of holes 361 need to be arranged in a line along the scanning direction X in order to be detected by the remaining amount sensor 201. The carriage 36 is provided with an adjustment dial 202 shown in FIG. 3, and by operating the adjustment dial 202, the carriage 36 can be rotated around the axis in the gravity direction Z to adjust its posture angle. It has become. By adjusting the attitude angle of the carriage 36, all of the plurality of holes 361 can be arranged in a line along the scanning direction X that can be detected by the remaining amount sensor 201.

  In the printing apparatus 12 according to the present embodiment, one of a plurality of types of feeding methods is selected according to a printing condition based on a print job. When the printing apparatus 12 receives a print job for plain paper, band printing, and single-sided printing, the printing start position of the succeeding medium P is maintained while maintaining a state in which the preceding medium P and the succeeding medium P are partially overlapped. Select the overlap feeding method with the overlap continuous transport that transports together. When the printing apparatus 12 receives a print job with other printing conditions, the normal feeding method of transporting the subsequent medium P to the print start position in a state where the preceding medium P and the subsequent medium P are spaced apart from each other. Select. When the overlap feeding method is selected, a stacking operation in which the leading end of the succeeding medium, which is the medium P transported next to the preceding medium, is superimposed on the trailing end of the preceding medium, which is the medium P transported first. Then, when the printing of the preceding medium is finished, the continuous feeding is performed in which the preceding medium and the succeeding medium are conveyed together to the printing start position of the succeeding medium while maintaining the overlapping state at that time. In addition, after the overlap operation and before the overlap continuous feeding, a skew removal operation is performed in which the leading edge of the subsequent medium abuts against the pair of transport rollers 33 to correct the skew (skew). Even when the overlap feeding method is selected, the overlap continuous feeding is performed only when a later-described overlap enabling condition for the preceding medium and the succeeding medium is satisfied.

  Further, in the stacking operation, the top of the succeeding medium is overlaid on the upper side of the trailing edge of the preceding medium, and the bottom of the trailing medium is stacked on the lower side of the trailing edge of the preceding medium. There is. The superposition operation of this embodiment is performed by superposition. Therefore, it is necessary to overlap the leading end portion of the subsequent medium above the trailing end portion of the preceding medium. Therefore, the guide member 55 superimposes the feeding direction of the medium P fed from the nip portion of the intermediate roller 30 with the second driven roller 32 so that the preceding medium and the succeeding medium overlap in the correct stacking order in the overlapping operation. Change to the upper guide direction, which is easier. The medium P fed from the final nip of the intermediate roller 30 at a predetermined feeding speed is made to follow the upper surface of the guide member 55, so that the feeding direction is changed to the upper substantially horizontal direction, and the medium P is sent substantially horizontally. The subsequent medium P is transported toward the transport roller pair 33 while maintaining the upper limit position along the oblique surface of the ceiling wall portion 56. As a result, the overlaying of the succeeding medium from the upper side (printing surface side) with respect to the preceding medium succeeds at a higher frequency.

  Further, the reason why the protruding end portion of the holding rib 581 shown in FIG. 3 is offset downward from the imaginary line connecting the nip position of the conveying roller pair 33 and the protruding end portion 57E of the support member 57 is as follows. It is.

  When the protruding end portion of the holding rib 581 is higher than the imaginary line, the rear end portion of the preceding medium is lifted, which causes trouble when the leading end portion of the succeeding medium is superimposed on the rear end portion of the preceding medium ( Reason 1). In addition, when the protruding end of the holding rib 581 is at a position lower than the imaginary line, the preceding medium is pressed below the imaginary line by the protruding end of the holding rib 581, so A slightly upstream portion is pressed against the protruding end portion 57E of the support member 57, and as a result, a portion located upstream of the protruding end portion 57E in the preceding medium is lifted. In this case as well, there is a problem when the leading edge of the succeeding medium is superimposed on the trailing edge of the preceding medium (reason 2).

  Further, when the protruding end portion of the pressing rib 581 is at a position lower than the imaginary line, the tip of the medium P pressed downward by the protruding end portion of the pressing rib 581 is made of powder such as alumina in the transport roller pair 33. It strikes against one of the transport drive rollers 33A that has been subjected to anti-slip treatment by application, and the tip of the medium P slides to the nip portion of the transport roller pair 33 due to the anti-slip action at the abutted portion. As a result, the assumed skew removal operation cannot be performed (reason 3).

  If it is designed in an ideal form so that the protruding end portion of the holding rib 581 is positioned on the imaginary line, there is a possibility that the above-mentioned disadvantageous situation may occur. Therefore, the problem due to the above-mentioned reason 1 is solved by designing the protruding end portion of the holding rib 581 to be positioned lower than the imaginary line. Further, the pressing rib 581 is biased downward by a spring load, and can be operated upward by the stiffness of the medium P. As a result, the above problems 2 and 3 are also solved.

  In addition, the skew removal operation for correcting the skew of the medium P is performed by sequentially changing the posture of the medium P from the state 1 to the state 5 shown below. First, the medium P is transported downstream while being guided along the ceiling wall portion 56 by the guide member 55 (state 1). Next, after the leading edge of the medium P is abutted against the stopped conveyance roller pair 33 and abuts, the medium P is given a conveyance force downstream by the intermediate roller 30 (state 2). Furthermore, since the conveying force from the intermediate roller 30 is applied in a state where a part of the stopped medium P hits the ceiling wall portion 56, the downstream portion is directed downward from the hit position. Deflection (state 3). As the deflection of the medium P grows, the deflection further grows in the downward direction while the position hitting the ceiling wall portion 56 gradually moves to the upstream side (see state 4, FIG. 12A). Then, the skew of the medium P is corrected by causing the end of the leading edge of the medium P to be along the conveyance roller pair 33 by the bending force thus completed (state 5). The medium P with the skew corrected is transported by the transport roller pair 33, so that the medium P is printed with the skew corrected.

  Here, the superposition possible condition determined in the printing apparatus 12 when the superposition feeding method is selected will be described. Overlapping continuous transmission is permitted when a stackable condition is satisfied. The superimposing condition includes a margin condition indicated by a condition in which the trailing end margin length (bottom margin) of the preceding medium and the leading end margin length (top margin) of the succeeding medium can be continuously superimposed. As for the margin condition, overlapping continuous feed is permitted when the trailing margin length of the preceding medium is in the range of about 30 mm to about 80 mm and the leading margin length of the trailing medium is about 15 mm or more. .

  As for the margin condition, overlapping continuous feeding is permitted when both the trailing margin length of the preceding medium and the leading margin length of the succeeding medium satisfy the following conditions. Here, as shown in FIG. 3, the distance between the nip position of the transport roller pair 33 and the downstream end position of the guide member 55 is LU, the distance between the nip position of the transport roller pair 33 and the most upstream nozzle #Q is Ln, The distance between the most downstream nozzle # 1 and the pressing roller 34C is Lr. The first condition is that the trailing edge margin length of the preceding medium is within the range of “distance Ln + α to distance LU”. Here, the leading end portion of the succeeding medium overlaps the α portion of the distance Ln + α. The second condition is that the leading margin length of the subsequent medium is equal to or longer than the distance Lr. By shortening the distance Lr or LU in FIG. 3, the amount of blank space necessary for continuous continuous feeding can be reduced. The distance Ln + α may be simply set to a value 2 · Ln that is twice the distance Ln.

  The reason why the trailing edge margin length of the preceding medium is required to be at least 30 mm is as follows. That is, the distance Ln from the most upstream nozzle #Q of the print head 38 to the nip position of the transport roller pair 33 is about 13 mm as an example, and the nip position of the transport roller pair 33 is an area where the leading edge of the subsequent medium overlaps. Since about 15 mm is required toward the upstream in the conveyance direction Y, the total is about 28 mm. Further, considering some manufacturing errors in the length of the medium P itself in the transport direction Y, the trailing edge margin length of the preceding medium requires at least about 30 mm in total.

  The reason why the trailing edge margin length of the preceding medium is 80 mm or less is as follows. That is, the distance LU from the nip position of the transport roller pair 33 to the downstream end in the transport direction Y of the guide member 55 is about 80 mm. Therefore, if it exceeds 80 mm, the trailing edge of the preceding medium reaches the guide member 55, and the leading edge of the succeeding medium cannot be overlapped.

  The reason why the trailing margin length of the subsequent medium is required to be about 15 mm is as follows. That is, the distance Lr from the most downstream nozzle # 1 of the print head 38 to the pressing roller 34C is about 14 mm, and about 15 mm is required in consideration of some manufacturing tolerances. The reason why the trailing margin length of about 15 mm is required for the subsequent medium is as follows. That is, if the leading end of the subsequent medium is not pressed before printing (ink ejection) on the subsequent medium is started, the medium P curls toward the print head 38 when ink is ejected, and the medium P against the print head 38 is detected. Rub will occur. Therefore, the leading edge of the medium P corresponding to the print head 38 from the most downstream nozzle # 1 to the pressing roller 34C is blank. Incidentally, the overlapping amount of the preceding medium and the succeeding medium changes depending on the trailing edge margin length of the preceding medium. That is, when the trailing edge margin length of the preceding medium is a minimum of 30 mm, about 17 mm is obtained by subtracting about 13 mm, which is the distance from the most upstream nozzle #Q of the print head 38 to the nip position of the conveying roller pair 33. This is the overlap amount of the medium and the subsequent medium.

  Further, when the trailing edge margin length of the preceding medium is 80 mm at the maximum, about 67 mm is obtained by subtracting about 13 mm which is the distance from the most upstream nozzle #Q of the print head 38 to the nip position of the conveying roller pair 33. This is the overlap amount of the medium and the subsequent medium. As described above, the overlap amount of the preceding medium and the succeeding medium varies in the range of about 17 mm to about 67 mm according to the trailing edge margin length of the preceding medium.

  With reference to FIG. 4, the structure of a section from the feeding roller 28 to the printing unit 25 in the transport mechanism 24 (hereinafter, an apparatus including the transport structure in this section is referred to as “medium transport apparatus 100”) will be described.

  The medium conveying apparatus 100 includes at least one roller pair that rotates while sandwiching the medium P, and further guides the medium P in a direction that intersects the direction along the tangential direction DX at the nip portion of the roller pair.

  In the present embodiment, the medium transport apparatus 100 includes an intermediate roller 30, two driven rollers 31 and 32 that are driven to rotate while sandwiching the medium P between the intermediate roller 30, and a guide member 55.

  The intermediate roller 30 is disposed at a substantially intermediate position in the rotation axis direction (the direction along the rotation axis 30a, that is, the width direction of the conveyance path). A plurality of guides 68 are arranged on both sides of the intermediate roller 30 in the rotation axis direction. The guide 68 supports the medium P conveyed to the upper side of the intermediate roller 30 from below, and guides the medium P so that the medium P travels toward the guide member 55.

  As described above, the first driven roller 31 and the second driven roller 32 having a smaller diameter than the intermediate roller 30 are disposed around the intermediate roller 30. The first driven roller 31 is disposed on the feeding roller 28 side in the transport path. The second driven roller 32 is downstream of the first driven roller 31 in the transport path and above the rotation shaft 30a of the intermediate roller 30 and the transport path (an arcuate transport path on the upper side along the intermediate roller 30). Are arranged at positions downstream of the uppermost PX. That is, the intermediate roller 30 and the second driven roller 32 are configured to sandwich the medium P so that the tangential direction DX at the nip portion becomes a downward gradient toward the downstream side in the conveyance direction of the medium P.

  The guide member 55 is disposed immediately downstream of the second driven roller 32 in the transport path. The guide member 55 changes the traveling direction of the medium P transported by the second driven roller 32 and the intermediate roller 30 (hereinafter, these two rollers are referred to as “pre-change mechanism roller pair 69”). The guide member 55 is configured such that the medium P slides on the contact surface 72 and slides downstream in the transport direction. The guide member 55 is configured as a flap 71, for example. The flap 71 can be configured to fly the front end of the medium P as shown in the present embodiment.

As described above, the conveyance roller pair 33 is disposed immediately before the printing unit 25 and conveys the medium P to the printing unit 25 by sandwiching and rotating the medium P.
The conveyance roller pair 33 is disposed below the second driven roller 32 and at a predetermined distance from the second driven roller 32. The predetermined distance is at least shorter than the length of the medium P (the length in the vertical direction along the transport path). The reason is to take a skew of the medium P. That is, in the skew removal, the medium P is pushed forward by the driving of the intermediate roller 30 in a state where the front end of the medium P is abutted against the transport roller pair 33 and is sandwiched between the change mechanism front roller pair 69. Is done.

A conveyance path of the medium P in the printing apparatus 12 will be described.
In the printing apparatus 12, the conveyance path of the medium P from the feeding roller 28 to the printing unit 25 includes a path having a drop in the vertical direction. In the present embodiment, a path having a drop in the vertical direction is provided between the second driven roller 32 and the transport roller pair 33. This route is configured as a space in which the medium P flies (hereinafter “flight space SP”). The medium P flying means that the front end (or rear end) of the medium P moves in the air without being supported. By such a flight, it is possible to superimpose the succeeding medium P on the rear part of the preceding medium P, and it is possible to convey a part of the preceding medium P and the succeeding medium P in an overlapping manner.

  The flying space SP is configured as a space between the ceiling wall portion 56 and the support member 57. That is, in the flying space SP, the medium P is restricted from moving upward by the ceiling wall portion 56, and the medium P is restricted from moving downward by the support member 57.

  The ceiling wall part 56 is arrange | positioned in the following positions. That is, the ceiling wall portion 56 is above a line (hereinafter referred to as “virtual line”) connecting the nip portion of the transport roller pair 33 and the nip portion of the pre-change-mechanism roller pair 69, and the medium P is located on the ceiling wall portion 56. It is arranged at a position where it is possible to suppress the movement (or bending) of the imaginary line greatly upward. With this configuration, the ceiling wall portion 56 suppresses escape of force applied to the medium P during skew removal.

  The support member 57 supports the medium P at a position lower than the rotation shaft 30 a of the intermediate roller 30. Thereby, a drop in the movement of the medium P in the vertical direction is ensured. This drop is ensured to ensure that the media P overlap. Preferably, the support member 57 supports the medium P at a position higher than the transport roller pair 33. Thereby, in addition to the conveyance force by the conveyance roller pair 33, the component force of gravity (component force in the conveyance direction) acts on the medium P, so that the medium P is smoothly conveyed.

Next, an example of the conveyance mode of the medium P will be described.
The feeding roller 28 and the intermediate roller 30 are driven by a first motor 631 (or a plurality of motors). The transport drive roller 33 </ b> A of the transport roller pair 33 and the discharge drive roller 34 </ b> A of the discharge roller pair 34 are driven by the second motor 632. The print head 38 is driven by the third motor 633. The first motor 631, the second motor 632, and the third motor 633 are controlled by the control device 600 (see FIG. 11).

  When printing is started, the control device 600 drives the first motor 631 to rotate the feeding roller 28 (281, 282) and the intermediate roller 30. Note that a motor different from the first motor 631 may be used for rotating the feeding roller 282 on the second cassette 22 side. The medium P is picked up from the first cassette 21 or the second cassette 22 by the rotation of the feeding roller 28 (281, 282) and the intermediate roller 30, and is conveyed by the intermediate roller 30. When the front end of the medium P passes through the first driven roller 31 and the second driven roller 32, the front end of the medium P is guided by the flap 71 and moves forward from the flap 71 at a horizontal or near-horizontal angle. That is, the medium P flies in the flying space SP between the second driven roller 32 and the transport roller pair 33. The front end of the medium P gradually descends and is disposed at a point on the upstream side of the transport roller pair 33. When the preceding medium P is being printed, the succeeding medium P overlaps the preceding medium P. Thereafter, when the intermediate roller 30 is driven and the medium P is pushed out, the medium P is sandwiched between the transport roller pair 33. The medium P is printed by the printing unit 25 after skew removal and cueing are executed.

With reference to FIG. 5, the specific example of the flap 71 as the guide member 55 is demonstrated.
The flap 71 is disposed immediately after the downstream side of the second driven roller 32. Preferably, the flap 71 is disposed such that the contact surface 72 is positioned above the rotation shaft 30 a of the intermediate roller 30. The flap 71 is configured so that the front end of the medium P is crossed from the tangential direction DX of the nip portion of the change mechanism front roller pair 69 in a state where the medium P is sandwiched between the change mechanism front roller pair 69 ( For example, it is guided in a horizontal direction or a direction that is higher than the tangential direction DX.

  The flap 71 has a contact surface 72. The contact surface 72 is configured such that the medium P transported downstream comes into contact with the rotation of the roller pair 69 before the change mechanism. The contact surface 72 is configured to be a flat surface or a curved surface, for example. Furthermore, the contact surface 72 is preferably configured as a smooth surface. The contact surface 72 of the flap 71 intersects the surface along the tangential direction DX of the nip portion in the pair of rollers 69 before the change mechanism. Preferably, the contact surface 72 of the flap 71 is horizontal.

  The length of the flap 71 is defined as follows. That is, for the purpose of making it possible to overlap the preceding medium P and the succeeding medium P, the distance from the front end of the flap 71 to the conveying roller pair 33 is set to a predetermined distance or more. Further, as described above, the flap 71 has a function of guiding the medium P in a direction toward the upper side of the tangential direction DX at the nip portion of the pair of rollers before changing mechanism 69. For this reason, the flap 71 is configured to have a length sufficient to orient the front end of the medium P in the direction. The length of the flap 71 (the length along the conveyance path) is set so that these requirements are satisfied.

  Further, the flap 71 is provided with a non-contact portion 73 where the medium P does not come in contact with the nip portion of the roller pair 69 before the change mechanism. The non-contact part 73 is comprised as a through-hole (refer FIG. 5) which penetrates the flap 71, or is comprised as a recessed part, for example. The width of the non-contact portion 73 (the length in the direction along the rotation shaft 30a) is longer than, for example, the width of the nip portion of the pre-change mechanism roller pair 69. Further, the non-contact portion 73 extends to the front end of the flap 71 along the conveyance path in the flap 71.

The operation of the non-contact part 73 will be described in comparison with an example in which the non-contact part 73 is not provided (see FIG. 7).
The medium P is pushed forward by the rotation of the change mechanism front roller pair 69. The medium P is bent when its front end contacts the flap 71, and its traveling direction is changed. As shown in FIG. 7, when the non-contact part 73 is not provided, the following event occurs. That is, when a portion (hereinafter, “clamping corresponding part PPA”) that is sandwiched between the change mechanism front roller pair 69 at the front end of the medium P comes into contact with the flap 71 (see the two-dot chain line LX in FIG. 7), the clamping corresponding part PPA. A force in the direction opposite to the advancing direction acts on the sandwiching corresponding portion PPA due to the friction between the flap 71 and the flap 71. On the other hand, a propulsive force based on the rotational force of the intermediate roller 30 acts on a portion of the medium P that is sandwiched between the pair of rollers before the change mechanism 69 (hereinafter, “clamping portion PPB”). Therefore, two forces in opposite directions act between the sandwiching part PPB and the sandwiching corresponding part PPA. For this reason, when the friction between the front end of the medium P and the flap 71 increases due to the roughness of the front end of the medium P, the medium P is not smoothly conveyed.

  In this regard, in the present embodiment, the flap 71 is provided with a non-contact portion 73 at a position facing the nip portion of the pre-change mechanism roller pair 69. For this reason, since two forces which are opposite to each other do not act on the portion between the sandwiching portion PPB and the sandwiching corresponding portion PPA, the medium P is smoothly conveyed.

  Further, the flap 71 can be configured such that the medium P is curved in a direction perpendicular to the conveyance path of the medium P and perpendicular to the vertical direction (that is, the width direction of the medium P). For example, a rib is provided on the flap 71 for the purpose of curving the medium P. Due to the curvature of the medium P, the medium P is prevented from drooping downward toward the front of the transport path. Further, in order to smoothly convey the medium P, it is preferable that the top portion of the rib has an arcuate shape in which the cross-sectional shape when viewed from the downstream side in the conveyance direction of the medium P is convex upward.

With reference to FIG. 6, the structural example of the ribs 74 and 75 provided in the flap 71 is demonstrated.
The flap 71 is provided with at least a pair of first ribs 74 and 74. The pair of first ribs 74 and 74 are disposed on both sides of the non-contact portion 73. Further, preferably, the flap 71 is provided with a pair of second ribs 75 and 75 arranged so as to sandwich the pair of first ribs 74 and 74.

  The distance LB between the first rib 74 and the second rib 75 disposed on one side (for example, the right side) of the second driven roller 32 is the distance LA between the pair of first ribs 74 and 74. Bigger than. Similarly, the distance LC between the first rib 74 and the second rib 75 arranged on the other side (for example, the left side) of the second driven roller 32 is between the pair of first ribs 74 and 74. It is larger than the distance LA.

  This rib configuration has the following effects. That is, the medium P sent out from the change mechanism front roller pair 69 is supported by the pair of first ribs 74 and 74 and the pair of second ribs 75 and 75. At this time, the medium P bends with these ribs 74 and 75 as fulcrums. Specifically, since the distance LA between the first ribs 74 and 74 is smaller than the distance LB and LC between the first rib 74 and the second rib 75, the first rib 74 is used as a boundary. The outer portion 77 is longer than the inner portion 76 and the outer portion 77 sinks downward, and the inner portion 76 is shorter than the outer portion 77 and the inner portion 76 is raised. Therefore, in the medium P, a portion between the pair of first ribs 74 and 74 is curved so as to bulge upward, and a portion between the first rib 74 and the second rib 75 is curved so as to sink downward. . As described above, according to the rib arrangement of the above configuration, the portion of the medium P arranged between the first ribs 74 and 74 is bulged upward.

With reference to FIGS. 7 to 10, the operation of the medium P passing through the medium transport apparatus 100 having the above configuration will be described.
7 and 8 are diagrams illustrating a medium transport device 1106 according to a comparative example. The two-dot chain line shown in FIG. 7 indicates the shape of the front end when the front end of the medium P reaches the position of the two-dot chain line.

  The flap 1121 shown in FIG. 7 does not have the non-contact part 73 shown in this embodiment and does not have a rib. In the conveyance path having such a flap 1121, the medium P moves as follows. The medium P is pushed forward by the rotation of the change mechanism front roller pair 69. The medium P is bent when its front end comes into contact with the flap 1121, and its traveling direction is changed. When the front end of the medium P passes through the front end of the flap 1121, it moves downward by its own weight as shown in FIG. That is, the front end of the medium P descends immediately after the flap 1121 passes. Further, when the medium P is transported, the front portion of the medium P hangs down and bends, and when the front end of the medium P contacts the support member 57, the bend is bent in a direction opposite to that immediately after the flap 1121. In this way, the medium P is curved in an S shape. If it is curved in an S shape like this, the medium P may be bent. In the case where the preceding medium P and the succeeding medium P are transported in an overlapping manner, the front end of the succeeding medium P is positioned behind the trailing end of the preceding medium P. There may be a problem that there is no overlap with the subsequent medium P.

  9 and 10 are views showing the flap 71 and its peripheral structure according to this embodiment. The two-dot chain line shown in FIG. 9 indicates the shape of the front end when the front end of the medium P reaches the position of the two-dot chain line.

  In the transport path according to the present embodiment, the medium P moves as follows. The medium P is pushed forward by the rotation of the change mechanism front roller pair 69. The sandwiching corresponding part PPA (the part sandwiched between the change mechanism front roller pair 69) enters the non-contact part 73, and both side parts of the sandwiching corresponding part PPA are in contact with the first rib 74. At this time, since the clamping support portion PPA is pushed out with a strong force by the propulsive force of the roller pair 69 in front of the change mechanism, the clamping support portion PPA is positioned below the upper surface of the first rib 74 ( (See the two-dot chain line LY in FIG. 9). When the medium P further moves forward and its front end approaches the front end of the flap 71, the first rib 74 serves as a fulcrum by the weight of the medium P, and the outer portion 77 of the first rib 74 is lowered downward. The inner portion 76 moves upward from the rib 74. That is, the sandwiching corresponding part PPA is positioned above the upper surface of the first rib 74 (see the two-dot chain line LZ in FIG. 9). At this time, the outer portion 77 of the first rib 74 comes into contact with the contact surface 72 of the flap 71. When the outer portion 77 of the first rib 74 comes into contact with the contact surface 72 of the flap 71, the medium P has a tangential direction at the nip portion of the change mechanism front roller pair 69 based on the pressing force by the change mechanism front roller pair 69. A force in a direction intersecting with DX (for example, the horizontal direction) is applied, and a force along the flap 71 is applied to the medium P. Further, the medium P is configured to be curved in the medium width direction, and as a result of increasing rigidity in the transport direction, the front end of the medium P jumps out of the flap 71 while maintaining the height position in the vertical direction. In this way, the front end of the medium P flies to a farther position than the comparative example.

  According to such an action, the medium P is unlikely to be broken in the transport structure having such a flight space SP. Further, when the preceding medium P and the succeeding medium P are transported in an overlapping manner, a situation in which the front part of the succeeding medium P does not overlap the rear part of the preceding medium P is unlikely to occur.

Next, the driving mechanism of each roller and the print head 38 in the printing apparatus 12 will be described.
The printing apparatus 12 includes three motors (hereinafter referred to as “first motor 631” to “third motor 633”) as a driving mechanism (see FIG. 11).

  The feeding roller 28 and the intermediate roller 30 are driven by a first motor 631. That is, the feeding roller 28 and the intermediate roller 30 are interlocked. The rotation ratio between the feeding roller 28 and the intermediate roller 30 is set to a predetermined value.

  The transport drive roller 33 </ b> A of the transport roller pair 33 and the discharge drive roller 34 </ b> A of the discharge roller pair 34 are driven by the second motor 632. The print head 38 is driven by the third motor 633. The first motor 631, the second motor 632, and the third motor 633 are controlled by the control device 600.

The control device 600 will be described with reference to FIG.
The control device 600 controls the driving of the first motor 631 to the third motor 633 based on output signals of three sensors (hereinafter referred to as “first sensor 634” to “third sensor 636”), and The transport position of P is controlled. For example, the control device 600 superimposes the preceding medium P and the succeeding medium P by driving control of the first motor 631, the second motor 632, and the third motor 633.

The first sensor 634 to the third sensor 636 detect the presence or absence of the medium P.
The first sensor 634 is disposed immediately upstream (upstream) of the transport roller pair 33 in the transport path. The second sensor 635 is disposed between the transport roller pair 33 and the second driven roller 32 and below the ceiling wall portion 56 in the transport path. The third sensor 636 is disposed immediately upstream (on the upstream side) of the second driven roller 32 in the transport path.

  For example, the first sensor 634 to the third sensor 636 are configured as switches having a lever that rotates when the medium P contacts. The first sensor 634 to the third sensor 636 are in an “ON” state when the medium P is detected, and are in an “OFF” state when the medium P is not detected. The control device 600 determines that the front end of the medium P has passed near the sensor based on the first sensor 634 to the third sensor 636 being switched from “OFF” to “ON”. The control device 600 determines that the rear end of the medium P has passed near the sensor based on the first sensor 634 to the third sensor 636 being switched from “ON” to “OFF”.

  The first sensor 634 is configured as a switch having the above-described swing member 58 (lever). That is, as described above, when the leading end of the medium P touches the flap portion 582 from the upstream side to the downstream side, the swing member 58 causes the flap portion 582 of the swing member 58 to be downstream in the transport direction Y. Rotate towards The first sensor 634 is configured to be in an “ON” state by rotation of the swing member 58, and is configured to output a predetermined signal to the control device 600 when in the “ON” state.

  The operation of the printing apparatus 12 will be described with reference to FIGS. 12A to 12E and FIG. Here, a description will be given of an overlapping transport operation (overlapping continuous feeding) in which the succeeding medium P is superimposed on the preceding medium P. In the following description, the preceding medium P is referred to as “preceding medium PA”, and the medium P following the preceding medium P is referred to as “subsequent medium PB”.

  When printing is started, the control device 600 drives the first motor 631 at a low speed (hereinafter referred to as “first speed”), and rotates the feed rollers 28 (281 and 282) and the intermediate roller 30. Note that a motor different from the first motor 631 may be used for rotating the feeding roller 282 on the second cassette 22 side. The preceding medium PA is picked up from the first cassette 21 (or the second cassette 22) by the rotation of the feeding rollers 28 (281, 282) and the intermediate roller 30, and is conveyed by the intermediate roller 30. When the front end of the preceding medium PA passes through the first driven roller 31 and the second driven roller 32 and reaches the first sensor 634, the first sensor 634 detects the front end of the preceding medium PA (that is, from “OFF” to “ Switching to “ON”). When the first sensor 634 detects the front end of the preceding medium PA, the control device 600 stops the first motor 631 after a predetermined amount of rotation from the detection timing based on the detection.

  Next, as shown in FIG. 12A, the preceding medium PA is skewed. Specifically, the control device 600 stops the second motor 632 and drives the first motor 631. That is, the preceding medium PA is pushed forward by the rotational driving of the intermediate roller 30 in a state where the preceding medium PA is abutted against the transport roller pair 33.

  Next, after elapse of a predetermined time, cueing of the preceding medium PA is executed. Specifically, the control device 600 drives the first motor 631 and the second motor 632 and conveys the preceding medium PA until the front end of the preceding medium PA reaches the print start position. When the preceding medium PA reaches the printing start position, the control device 600 drives the third motor 633 and starts printing by the printing unit 25.

  Thereafter, as the printing progresses, the control device 600 intermittently drives the transport roller pair 33, the discharge roller pair 34, and the intermediate roller 30 to transport the preceding medium PA intermittently. A series of operations in which printing is performed by the printing unit 25 reciprocating while the conveyance is stopped is referred to as “one pass”, and the last pass in one medium P is referred to as a “last pass”.

  As the printing of the preceding medium PA proceeds, the medium P advances intermittently. When the trailing edge of the preceding medium PA passes the feeding roller 28, the succeeding medium PB is picked up by the feeding roller 28. At this time, the rotation speed of the feeding roller 28 is controlled to be slower than the rotation speeds of the conveyance roller pair 33 and the discharge roller pair 34. As a result, the rear end of the preceding medium PA is separated from the front end of the subsequent medium PB.

  As shown in FIG. 12B, when the trailing edge of the preceding medium PA passes through the third sensor 636 and the third sensor 636 detects the trailing edge of the preceding medium PA (ie, switching from “ON” to “OFF”). 13 (see time t1 in FIG. 13), the rotation speed of the first motor 631 is increased based on this detection. The first motor 631 is driven at a predetermined high speed (speed faster than the first speed). Due to the high speed driving of the first motor 631, the intermediate roller 30 rotates at a high speed, the movement of the subsequent medium PB becomes faster, and the subsequent medium PB approaches the preceding medium PA.

  After the trailing edge of the preceding medium PA passes through the third sensor 636, the trailing edge of the preceding medium PA passes through the second driven roller 32 and the flap 71. Then, since the rear end of the preceding medium PA is not supported, the rear part of the preceding medium PA is lowered. On the other hand, the succeeding medium PB is conveyed at high speed so that the succeeding medium PB approaches the preceding medium PA over a period before and after the lower part of the rear of the preceding medium PA. For this reason, when the front end of the subsequent medium PB passes through the second driven roller 32 and the flap 71, momentum due to high-speed conveyance is applied, and the front end of the subsequent medium PB passes above the rear portion of the preceding medium PA (see FIG. 12C). ). In this way, the rear part of the preceding medium PA and the front part of the subsequent medium PB overlap.

  As shown in FIG. 12C, the front end of the subsequent medium PB passes in the vicinity of the second sensor 635 when passing over the rear part of the preceding medium PA. The control device 600 determines whether or not the overlap between the preceding medium PA and the succeeding medium PB is successful based on the second sensor 635 detecting the front end of the succeeding medium PB (see time t2 in FIG. 13). .

The control device 600 stops high-speed driving of the first motor 631 after a predetermined time from when the third sensor 636 detects the trailing edge of the preceding medium PA.
As a result, as shown in FIG. 12D, the transport of the subsequent medium PB is stopped until the pass immediately before the last pass of printing of the preceding medium PA is completed.

  As shown in FIG. 12E, when the pass immediately before the last pass of printing of the preceding medium PA is completed (see time t3 in FIG. 13), the control device 600 drives both the first motor 631 and the second motor 632. . Accordingly, the preceding medium PA is transported by the transport roller pair 33 and the subsequent medium PB is transported by the transport roller pair 33 and the intermediate roller 30. Thereafter, the control device 600 stops only the second motor 632 after a predetermined time TA has elapsed from the start of rotation of the first motor 631 and the second motor 632 (that is, at time t4). That is, the control device 600 drives the intermediate roller 30 to push the succeeding medium PB forward in a state where the front end of the succeeding medium PB is abutted against the transport roller pair 33 in the stopped state (predetermined after time t4 in FIG. 13). time). Thereby, the skew removal of the subsequent medium PB is executed. After the skew removal is performed, cueing of the subsequent medium PB is performed. For control purposes, the succeeding medium PB shown in FIG. 12E is handled as the preceding medium PA, and the operations after cueing are repeated.

Next, the overlap determination performed by the control device 600 will be described.
In the above-described transport process in which the preceding medium PA and the succeeding medium PB are overlapped, it may be assumed that no overlap occurs. For example, when the front end of the subsequent medium PB passes through the flap 71, it is also assumed that the front part of the subsequent medium PB hangs down. In this case, when the front end of the subsequent medium PB comes into contact with the rear end of the preceding medium PA as the subsequent medium PB is conveyed forward, the subsequent medium PB does not overlap the preceding medium PA. In order to detect that the preceding medium PA and the succeeding medium PB do not overlap as described above, it is preferable to provide the second sensor 635 described above.

  As shown in FIG. 12C, when the front end of the succeeding medium PB passes a predetermined height position (predetermined height position higher by a predetermined distance from the support member 57) or higher than the predetermined height position, The front end of the medium PB is detected by the second sensor 635. On the other hand, when the front end of the subsequent medium PB passes below the predetermined height position, the front end of the subsequent medium PB is not detected by the second sensor 635. Based on the second sensor 635 detecting the front end of the subsequent medium PB at a predetermined timing (that is, switching from “OFF” to “ON”; time t2 in FIG. 13), the control device 600 performs the preceding. It is determined that the medium PA and the subsequent medium PB overlap. The control device 600 also overlaps the preceding medium PA and the succeeding medium PB based on the fact that the second sensor 635 does not detect the front end of the succeeding medium PB at a predetermined timing (that is, maintains the “OFF” state). Judge that it is not. Here, the predetermined timing indicates a timing after the elapse of a predetermined time from the time when the front end of the succeeding medium PB passes the third sensor 636.

According to the medium conveyance device 100 of the present embodiment, the following effects can be obtained.
(1) The medium transport apparatus 100 includes a guide member 55 disposed on the downstream side of the second driven roller 32. The guide member 55 is configured as a flap 71. The flap 71 moves the medium P conveyed downstream from the nip portion by rotating the pair of rollers 69 (both rollers 30 and 32) before the change mechanism while the medium P is sandwiched between the tangent direction DX at the nip portion. Guide in the crossing direction. Then, in the flap 71, the portion is opposed to the nip portion in the direction along the rotation axis of the intermediate roller 30 or the second driven roller 32, and is conveyed along with the rotation of the pre-change mechanism roller pair 69 (both rollers 30 and 32). A non-contact part 73 that does not come into contact with the medium P is provided.

  Usually, when the medium P is conveyed by rotating both rollers while being sandwiched between the intermediate roller 30 and the second driven roller 32, the medium P is moved to both rollers 30, 32 (the roller pair 69 before the change mechanism). A propulsive force on the downstream side in the transport direction acts on the portion that has been sandwiched (the sandwiching-corresponding portion). For this reason, in the state in which the portion on the front end side of the medium P that is sandwiched between the rollers 30 and 32 is in contact with the guide member 55, the frictional force between the front end portion and the guide member 55. When becomes large, smooth conveyance of the medium P is hindered.

  In this regard, according to the above-described configuration, the non-contact portion 73 where the medium P does not come into contact with the nip portion in the guide member 55 in the direction along the rotation axis of each of the rollers 30 and 32 is present. For this reason, the portion of the medium P that is sandwiched between the rollers 30 and 32 (the sandwiching-corresponding portion) does not come into contact with the guide member, and it is difficult for a situation in which smooth conveyance of the medium P is hindered.

  (2) The guide member 55 has a contact surface 72 with which the medium P conveyed downstream as the change mechanism front roller pair 69 rotates, and a non-contact portion 73 configured by a recess or a through hole. The flap 71 can be configured such that the medium P slides on the contact surface 72 to the downstream side in the transport direction. And it is preferable that the contact surface 72 is comprised so that it may cross | intersect with respect to the surface in alignment with the tangent direction DX in a nip location.

  According to this configuration, the flap 71 in which the medium P is in contact with the contact surface 72 in a sliding state is provided not only with the contact surface 72 with which the medium P is in contact but also with the non-contact portion 73 with which the medium P does not contact at that time. It has been. For this reason, the portion of the medium P being transported that is sandwiched between the pair of rollers before the change mechanism 69 (the sandwiching corresponding portion) passes through the position where the non-contact portion 73 is provided in the flap 71 and does not contact the contact surface 72. Therefore, the medium P is smoothly conveyed.

(3) In the flap 71, the 1st rib 74 extended along a conveyance path | route is provided in the both sides of the non-contact part 73 in the direction in alignment with the rotating shaft 30a of the intermediate roller 30. As shown in FIG.
According to this configuration, both sides of the portion of the medium P that advances from the nip portion of the change mechanism front roller pair 69 to the non-contact portion 73 (that is, the sandwiching corresponding portion PPA) are lifted by the first rib 74, so It bends and the rigidity (difficulty of bending) of the medium P in the transport direction increases.

  (4) Further, the flap 71 includes a first rib 74 and a pair of second ribs 75 arranged on the outer side in the direction along the rotation shaft 30 a than the first rib 74. The distances LB and LC between the first rib 74 and the second rib 75 are longer than the distance LA between the pair of first ribs 74. According to this configuration, in the medium P, the outer portion 77 hangs down from the first rib 74 with the first rib 74 as a fulcrum in the rotation axis direction (the axial direction of the rotation shaft 30a, that is, the width direction of the transport path). The inner portion 76 rises from the one rib 74. Thereby, the medium P is curved at a plurality of locations in the direction along the rotation shaft 30a, and the rigidity in the transport direction is increased.

  (5) It is preferable that the top portions of the first rib 74 and the second rib 75 have a circular arc shape whose cross-sectional shape when viewed from the downstream side in the conveyance direction of the medium P is convex upward. According to this configuration, the medium P transported downstream in the transport direction has a transport load when the top of the first rib 74 and the second rib 75 slides, and the top of the ribs 74 and 75 is one surface of the medium P. It is reduced as compared with the case of a flat shape that can come into surface contact.

  (6) The contact surface 72 of the flap 71 is preferably configured as a smooth surface. According to this configuration, the transport load when the medium P transported downstream in the transport direction contacts the contact surface 72 in a sliding state is reduced as compared with the case where the contact surface 72 is a non-smooth surface.

  (7) According to the printing apparatus 12 having the medium conveyance apparatus 100 and the printing unit 25 having the above-described configuration, the same operational effects as those of the medium conveyance apparatus 100 can be enjoyed. That is, according to such a printing apparatus 12, the medium P is smoothly conveyed in the conveyance path that guides the medium P in a direction intersecting the tangential direction DX at the nip portion while the medium P is sandwiched by the roller pair. be able to.

<Modification>
-With reference to FIG. 14, the alternative example of the above-mentioned guide member 55 is demonstrated. The medium transport apparatus 1206 has the same structure as that of the embodiment with respect to the configuration other than the guide member 1220. Components other than the guide member 1220 are denoted by the same reference numerals as in the embodiment.

The guide member 1220 includes a plurality of poles 1221 and 1222 arranged along the rotation axis direction of the intermediate roller 30.
These poles 1221 and 1222 are connected by a connecting member 1224. The poles 1221 and 1222 have contact surfaces 1221a and 1222a with which the medium P contacts. The contact surfaces 1221a and 1222a of the poles 1221 and 1222 intersect the surface along the tangential direction DX at the nip portion of the pair of rollers 65 before the change mechanism.

  A pair of poles (hereinafter referred to as “first pole 1221”) among the plurality of poles are arranged so as to sandwich the front region of the change mechanism front roller pair 69. That is, the region between the pair of first poles 1221 is configured as a non-contact portion 1223 where the medium P does not contact. Of the plurality of poles, poles other than the pair of first poles 1221 (hereinafter referred to as “second pole 1222”) are arranged at an arbitrary interval. The distance between the pair of first poles 1221 is between the first pole 1221 and the second pole 1222 (the first second pole 1222 of the first poles 1222 outside the first pole 1221). It is smaller than the distance of.

  In such a guide member 1220, the medium P is supported by the plurality of poles 1221 and 1222 and guided in a direction crossing the tangential direction DX at the nip portion of the change mechanism front roller pair 69. Since the guide member 1220 is provided with the non-contact portion 1223 at a position facing the nip position of the pre-change mechanism roller pair 69, the portion of the medium P that has been nipped by the pre-change mechanism roller pair 69 (nipping The corresponding part PPA) does not come into contact with the guide member 1220. In this way, a situation in which smooth conveyance of the medium P is hindered is less likely to occur.

<Other embodiments>
With reference to FIG. 15, another example of the medium transport device will be described.
The medium conveyance device 1306 guides the medium P in a direction that intersects the direction along the tangential direction of the roller pair, as in the above embodiment. An arrow DP in FIG. 15 indicates the conveyance direction of the medium P. This will be specifically described below.

  The medium transport apparatus 1306 includes a driving roller 1310, a driven roller 1311 that is driven by the driving roller 1310, and a guide member 1320 that guides the medium P. The drive roller 1310 and the driven roller 1311 convey the medium P entering along the tangential direction between the drive roller 1310 and the driven roller 1311 to the downstream side of the conveyance path.

  The guide member 1320 is disposed immediately downstream of the roller pair 1312 configured by the driving roller 1310 and the driven roller 1311 and changes the traveling direction of the medium P conveyed by the roller pair 1312.

  The guide member 1320 is configured as an array in which a plurality of guide constituent members 1321 are arranged in a row at intervals. The guide component 1321 has a curved surface 1321a that curves the medium P along the medium P. The guide component 1321 is arranged with a region facing the nip portion of the roller pair 1312 as a space. That is, the non-contact portion 1323 that the medium P does not contact is configured as a space between the guide constituent members 1321.

The medium P is conveyed as follows.
When the medium P is conveyed by the roller pair 1312 and the front end of the medium P moves to the downstream side of the roller pair 1312, the medium P comes into contact with the guide member 1320 and the tangential direction at the nip portion of the roller pair 1312. Guided in the crossing direction. Since the guide member 1320 is provided with a non-contact portion 1223 at a position opposite to the nip position of the roller pair 1312, when the medium P is guided by the guide member 1320, the medium P is moved by the roller pair 69 before the change mechanism. The portion that has been sandwiched (the sandwiching corresponding portion PPA) does not contact the guide member 1320. For this reason, it becomes difficult to generate | occur | produce the situation where the smooth conveyance of the medium P is prevented.

  The guide member 1320 can be changed as follows. The guide member 1320 is not configured by a plurality of guide component members 1321, but may be configured as having a recess or a through hole as the non-contact portion 1323. For example, in the example shown in FIG. 15, the guide member 1320 is a connecting member 1340 (refer to the two-dot chain line in FIG. 15) so that a recess or a through hole as the non-contact portion 1323 is formed. Can be linked.

DESCRIPTION OF SYMBOLS 12 ... Printing apparatus, 25 ... Printing part, 100, 1106, 1206, 1306 ... Medium conveying apparatus, 30 ... Intermediate roller (drive roller), 30a ... Rotating shaft, 31 ... 1st driven roller, 32 ... 2nd driven roller, 57 ... Support member, 68 ... Guide, 69 ... Roller pair before change mechanism, 55, 1220, 1320 ... Guide member, 71, 1121 ... Flap,
72, 1221a, 1222a ... contact surface, 73, 1223, 1323 ... non-contact part, 74 ... first rib, 75 ... second rib, 1221 ... first pole, 1222 ... second pole, 1310 ... drive roller, 1311 ... Follower roller, 1321 ... guide component, 1321a ... curved surface.

Claims (7)

A driving roller, a driven roller that sandwiches the medium together with the driving roller, and a guide member that is arranged on the downstream side of the nip portion of the medium by the both rollers in the medium transport path,
The guide member guides the medium transported downstream from the nip portion by rotating both rollers while sandwiching the medium in a direction intersecting a tangential direction at the nip portion. And a non-contact portion where the medium conveyed along with the rotation of the two rollers is not in contact with the nip in the direction along the rotation axis of each roller. . The driving roller and the driven roller are configured to sandwich the medium such that a tangential direction at the nip portion is a downward gradient toward the downstream side in the conveyance direction of the medium,
The guide member has a contact surface with which the medium conveyed downstream with the rotation of the rollers contacts, and the non-contact portion configured by a recess or a through hole. The medium is configured as a flap that slides and passes downstream in the transport direction,
The medium conveying apparatus according to claim 1, wherein the contact surface is configured to intersect a surface along a tangential direction at the nip portion. The medium transport apparatus according to claim 2, wherein ribs extending along the transport path are provided on both sides of the non-contact portion in a direction along the rotation axis of the drive roller in the guide member. The guide member includes a pair of first ribs as the ribs, and a pair of second ribs arranged on the outer side in the direction along the rotation axis than the pair of first ribs,
The medium conveyance device according to claim 3, wherein a distance between the first rib and the second rib is longer than a distance between the pair of first ribs. The medium conveyance device according to claim 3, wherein the top portion of the rib has an arc shape with a cross-sectional shape upwardly convex when viewed from the downstream side in the conveyance direction of the medium. The medium conveying device according to any one of claims 2 to 5, wherein the contact surface is configured as a smooth surface. The medium conveyance device according to any one of claims 1 to 6,
And a printing unit that performs printing on the medium conveyed by the medium conveyance device.

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