JP2013060265A - Medium conveying device and printer - Google Patents

Abstract

To provide a printer capable of preventing skew of a recording sheet when a long recording sheet is conveyed in a forward direction and a reverse direction by two drive roller pairs separated in the conveying direction.
A printer 1 includes guide surfaces 20 and 21 that are in contact with both ends in the width direction of a label sheet 2 on a conveyance path 14 that extends through a platen 12 that defines a printing position A, and guide surfaces 20 and 21. A paper feed roller pair 40 disposed on the downstream side in the forward direction D1 and a feed roller pair 30 disposed on the upstream side are provided. When transporting the label paper 2 in the forward direction D1, the feeding roller pair 30 is opened, and the label paper 2 is nipped and transported by the paper feed roller pair 40. When transporting the label paper 2 in the reverse direction D2, the paper feed roller pair 40 is opened, and the label paper 2 is nipped by the feed roller pair 30 and transported. Thereby, the label paper 2 can be conveyed along the guide surfaces 20 and 21, and the occurrence of skew can be prevented.
[Selection] Figure 4

Description

  The present invention relates to a medium conveying apparatus and a printer that convey a long sheet-like medium fed out from a roll paper in two directions, which are separated from each other in a conveying direction, in a forward direction and a reverse direction.

  A medium processing apparatus that transports a sheet-like medium in the forward direction and the reverse direction along the transport path is described in Patent Document 1. The medium processing apparatus of the same document includes two drive roller pairs that can nip and convey a sheet-like medium at positions separated in the conveyance direction. Each drive roller pair includes a drive roller disposed on the lower side of the conveyance path and a press roller disposed on the upper side. The press roller is a nip position where the sheet-like medium is nipped between the drive roller and the drive roller. It can move between an open position where a gap larger than the thickness of the sheet medium is formed with the roller. When the sheet-like medium is conveyed in the forward direction and the reverse direction, the pressing roller of one drive roller pair located on the downstream side in the conveyance direction is moved to the open position to bring the drive roller pair into an open state. The pressing roller of the other driving roller pair positioned on the upstream side is moved to the nip position to bring the driving roller pair into the nip state, and the driving roller pair positioned on the upstream side is driven to convey the sheet-like medium. .

JP 2006-3719 A

  Here, it is considered that a long sheet-shaped medium fed out from a roll paper is conveyed in the forward direction and the reverse direction by a medium conveyance device having two drive roller pairs arranged at positions separated in the conveyance direction. It is done. Further, in this case, a guide surface is provided between the two drive roller pairs to contact the edge in the width direction of the sheet-like medium from the direction orthogonal to the conveyance direction and guide the sheet-like medium in the conveyance direction, It is conceivable to prevent the sheet-like medium from skewing.

  In such a medium conveying apparatus, as in Patent Document 1, when a sheet-like medium is nipped and conveyed only by a pair of driving rollers located on the upstream side in the conveying direction, tension is generated in the sheet-like medium passing through the guide surface. Therefore, the sheet-like medium is not conveyed along the guide surface, and skew occurs. Therefore, it is conceivable to nip the sheet medium with both driving roller pairs arranged on the upstream side and the downstream side of the guide surface, and drive both driving rollers to convey the sheet medium. If there is a difference between the rotation amount of the upstream drive roller pair and the rotation amount of the downstream drive roller pair, the sheet-like medium is distorted between the two drive roller pairs, and the sheet shape on the conveyance path The position of the medium becomes unstable. As a result, the sheet-like medium is not conveyed along the guide surface, and skew occurs.

  In view of this point, the problem of the present invention is that when a long sheet-shaped medium fed out of roll paper is conveyed in the forward direction and the reverse direction by two drive roller pairs separated in the conveyance direction, An object of the present invention is to provide a medium transport apparatus and a printer that can prevent or suppress the occurrence of skew in a medium.

In order to solve the above problems, the present invention provides:
In a medium transport apparatus that transports a long sheet-shaped medium fed out of roll paper in the forward direction and the reverse direction along the transport path,
A guide surface that contacts the edge in the width direction of the sheet-shaped medium from a direction orthogonal to the conveying direction and guides the sheet-shaped medium in the conveying direction;
Two drive roller pairs arranged on both sides of the guide surface in the transport direction;
A roller pair displacement mechanism for displacing each drive roller pair between a nip state in which the sheet-like medium is nipped and an open state in which the sheet-like medium is opened;
When transporting the sheet-like medium in the forward direction and the reverse direction, one of the drive roller pairs positioned on the downstream side in the transport direction is brought into a nip state and the other pair of drive rollers positioned on the upstream side A conveyance control unit that conveys the sheet-like medium by driving one of the driving roller pairs located on the downstream side,
It is characterized by having.

  According to the present invention, since the sheet-like medium is conveyed while being pulled by one drive roller pair positioned on the downstream side in the conveying direction, tension is generated in the sheet-like medium passing through the guide surface. As a result, since the sheet-like medium can be conveyed along the guide surface, the occurrence of skew can be prevented or suppressed. In addition, since the drive roller pair positioned upstream in the transport direction among the two drive roller pairs is opened, the rotation of the drive roller pair upstream in the transport direction affects the transport of the sheet-like medium. Can be suppressed. As a result, the sheet-like medium is not distorted due to the difference in rotation amount between the two drive roller pairs and the position of the sheet-like medium on the conveyance path is not unstable. And can prevent or suppress the occurrence of skew.

  In the present invention, it is desirable that the guide surfaces include a pair of guide surfaces that can come into contact with both end edges in the width direction of the sheet-like medium. In this way, it is possible to further suppress the occurrence of skew in the sheet-like medium.

Next, the printer of the present invention is
Having the above-mentioned medium conveying device,
The sheet-like medium is a recording paper,
The conveyance path extends from a roll paper loading unit on which the roll paper is loaded in a rollable manner via a print position by a print head,
The two drive roller pairs and the guide surface are located between the roll paper loading unit and the printing position.

  According to the printer of the present invention, since the medium transport device is provided, the occurrence of the skew of the recording paper is prevented or suppressed when the recording paper is transported in the forward direction toward the printing position. Further, when the recording paper is conveyed in the reverse direction in order to align the print start target position on the recording paper with the printing position by the print head, the occurrence of skew of the recording paper is prevented or suppressed. Therefore, it is possible to prevent the print quality from being deteriorated by the print head due to the skew of the recording paper.

  Here, in a printer having a configuration in which the recording paper is fed from the roll paper loaded in the roll paper loading unit, when the recording paper is conveyed in the forward direction from the roll paper loading unit to the printing position, the roll paper loading Tension is applied to the recording paper by a load generated on the recording paper when the roll paper rolls in the section, for example, a frictional force between the roll paper and the roll paper loading unit or an inertial force acting on the roll paper. That is, when the recording paper is transported in the forward direction, the tension is applied to the recording paper on the upstream side in the transport direction from the guide surface, so the drive roller pair positioned on the upstream side in the transport direction is opened. Even in this case, the recording paper passing through the guide surface is not slackened or distorted, and the recording paper can be conveyed along the guide surface. As a result, the occurrence of skew in the recording paper can be reliably prevented. On the other hand, when the recording paper is transported in the reverse direction from the printing position toward the roll paper loading unit, the recording paper is fed upstream of the guide surface in the transport direction as in the above-described roll paper and roll paper loading unit. Since there is nothing to apply tension, when the drive roller pair located upstream in the transport direction is opened, it is possible to completely avoid the case where the recording paper passing through the guide surface is loosened or distorted. It becomes difficult. For this reason, the recording paper cannot be conveyed along the guide surface, and the recording paper may be skewed. With respect to such a problem, the printing position is defined by a platen, and the platen sucks air from a suction port formed on the platen surface and moves the recording paper conveyed through the printing position from the platen surface. A suction platen sucking so as not to be lifted, and provided with a configuration that applies tension to the recording paper by suction when at least the recording paper is transported in a direction from the printing position toward the roll paper loading unit; For example, when the recording paper is transported in the reverse direction from the printing position toward the roll paper loading unit, tension can be applied to the recording paper on the upstream side in the transport direction from the guide surface. Therefore, even when the recording paper is conveyed in the reverse direction, it is possible to reliably prevent the recording paper from being skewed.

  In the present invention, the print head is an ink jet head, and prints on the recording paper conveyed through the print position in a state stopped at the print position. That is, if the above-mentioned medium transport device is mounted on a line ink jet printer that tends to cause a drop in print quality when skew occurs in the recording paper, the print quality can be maintained.

  According to the medium conveying apparatus of the present invention, when the long sheet-shaped medium fed from the roll paper is conveyed in the forward direction and the reverse direction by the two driving roller pairs separated in the conveying direction, the two driving rollers are used. The sheet-like medium can be placed along the guide surface disposed between the pair. Therefore, it is possible to prevent or suppress the occurrence of skew in the sheet-like medium conveyed along the conveyance path.

  Further, according to the printer of the present invention, since the skew of the recording paper transported through the printing position is prevented or suppressed, it is possible to prevent the print quality from being lowered by the print head due to the skew of the recording paper.

1 is an explanatory diagram illustrating an overall configuration of a printer and a label sheet according to the present invention. FIG. It is a perspective view of the mechanism for conveying label paper. FIG. 5 is a schematic block diagram of a control system that controls a label sheet transport operation. It is explanatory drawing of the conveyance operation which conveys a label paper to the normal / reverse direction.

  A printer to which the present invention is applied will be described below with reference to the drawings.

(overall structure)
FIG. 1A is a schematic longitudinal sectional view showing the overall configuration of a printer according to an embodiment of the present invention, and FIG. 1B is a perspective view of a label sheet loaded in the printer. FIG. 2 is a perspective view of the mechanism for transporting the label paper as viewed from above the front of the printer. The printer 1 of the present invention is a line inkjet printer that performs printing on a long label paper (sheet-like medium / recording paper) 2 using a plurality of types of color inks. As shown in FIG. 1 (b), the label paper 2 has a constant width in a state where it can be peeled at regular intervals along the length direction on the surface of the long base 4 fed from the roll paper 3. And the label 5 of a fixed length is affixed.

  As shown in FIG. 1A, a roll paper loading chamber (roll paper loading section) 10 in which the roll paper 3 is loaded in a rollable state is provided at the rear portion of the printer 1. The label paper 2 (the mount 4 and the label 5) drawn from the roll paper 3 loaded in the roll paper loading chamber 10 passes through the platen 12 that defines the printing position A by the ink jet head 11, and the paper discharge port 13. It is conveyed along the conveyance path 14 leading to.

  A paper guide 15 for preventing skew of the label paper 2 is disposed above the roll paper loading chamber 10. As shown in FIG. 2, the paper guide 15 includes a frame portion 17 having a conveyance surface 16 that defines a conveyance path portion above the roll paper loading chamber 10 in the conveyance path 14, and the conveyance path 14 from the printer width direction. A pair of guide portions 18 and 19 are provided. The conveyance surface 16 is slightly inclined downward toward the front of the printer.

  Inner side surfaces facing each other in the pair of guide portions 18 and 19 are guide surfaces 20 and 21 perpendicular to the transport surface 16. The pair of guide surfaces 20 and 21 abuts the edge in the width direction of the label paper 2 from the printer width direction orthogonal to the transport direction, and guides the label paper 2 in the transport direction. In this example, one guide portion 19 of the pair of guide portions 18 and 19 is attached to the frame portion 17 so as to be slidable in the printer width direction, and the guide portion 19 is moved in the printer width direction. Thus, it is possible to finely adjust the width dimension in which the guide surfaces 20 and 21 face each other.

  A load roller 22 is provided at the rear end portion of the frame portion 17. The load roller 22 is positioned substantially at the center of the pair of guide surfaces 20 and 21 in the printer width direction, and allows the label paper 2 drawn out to the conveyance path 14 to pass between the load roller 22 and the frame portion 17. It is being fixed to the frame part 17 in the state which is possible. The width dimension of the load roller 22 is 1/6 or less of the width dimension in which the guide surfaces 20 and 21 face each other.

  A feeding roller pair (drive roller pair) 30 is disposed obliquely above the paper guide 15 at the rear of the printer. The feeding roller pair 30 is located at the center of the transport path 14 in the printer width direction. The feeding roller pair 30 has a smaller diameter than the feeding roller 32 that is rotated in the forward and reverse directions by a feeding motor 31 (see FIG. 3), and can nip the label paper 2 between the feeding roller 32. A feed presser roller 33 is provided. The width dimension of the feeding roller 32 is shorter than ½ of the width dimension of the transport path 14. The width dimension of the feed presser roller 33 is shorter than the width dimension of the feed roller 32 and is the same dimension as the load roller 22.

  Further, the feeding press roller 33 has a label paper 2 between the feed roller 32 and a nip position 33 </ b> A where the label paper 2 is nipped between the feed roller 32 by a feed press roller moving mechanism (roller pair displacement mechanism) 34. It is moved between the open position 33B that forms a space of a thickness dimension or more. When the feeding and pressing roller 33 moves to the nip position 33A, the feeding roller pair 30 enters a nip state where the label paper 2 is nipped. When the feeding and pressing roller 33 moves to the opening position 33B, the feeding roller pair 30 opens the label paper 2. It becomes an open state. The feed press roller moving mechanism 34 includes a press roller moving motor 35 (see FIG. 3) as a drive source for moving the feed press roller 33. When the feed press roller 33 is disposed at the nip position 33A, the feed press roller 33 is pressed against the central portion of the feed roller 32 in the printer width direction.

  A paper feed roller pair (drive roller pair) 40 is arranged in front of the paper guide 15 in the printer. The paper feed roller pair 40 includes a paper feed roller 41 that comes into contact with the label paper 2 from below and a paper feed press roller that can come into contact with the label paper 2 from above and nip the label paper 2 between the paper feed rollers 41. 42 is provided. A paper feed motor 43 for rotating the paper feed roller 41 in the forward and reverse directions is disposed below the paper feed roller pair 40. Between the paper feed motor 43 and the paper feed roller 41, a speed reduction mechanism 44 that decelerates the rotation of the paper feed motor 43 and transmits it to the paper feed roller 41 is configured.

  The paper feed roller 41 has a width dimension similar to the width dimension between the pair of guide surfaces 20 and 21. The width dimension of the paper feed presser roller 42 is 1/6 or less of the width dimension of the paper feed roller 41 and is the same dimension as the load roller 22. The paper feed presser roller 42 has a label between the paper feed roller 41 and a nip position 42A where the label paper 2 is nipped with the paper feed roller 41 by a paper feed presser roller moving mechanism (roller pair displacement mechanism) 45. It is moved between the open positions 42 </ b> B that form a space larger than the thickness dimension of the paper 2. When the paper feed presser roller 42 moves to the nip position 42A, the paper feed roller pair 40 enters a nip state that nips the label paper 2. When the paper feed presser roller 42 moves to the open position 42B, the paper feed roller pair 40 moves to the label paper. 2 is opened. The paper feed presser roller moving mechanism 45 includes a presser roller moving motor 46 (see FIG. 3) as a drive source for moving the paper feed presser roller 42. When the paper feed press roller 42 is disposed at the nip position 42A, the paper feed press roller 42 is pressed against the central portion of the paper feed roller 41 in the printer width direction.

  A platen 12 is disposed in front of the paper feed roller 41 in the printer. The platen 12 is a suction platen that sucks air from a plurality of suction ports 50 formed on the platen surface 12a and sucks the label paper 2 conveyed through the printing position A so as not to float from the platen surface 12a.

  An ink jet head 11 mounted on a carriage 51 is disposed above the platen 12. The inkjet head 11 is formed wider than the label paper 2, and the ink nozzles are arranged in a region having a width that can cover the label 5 (printing region) of the label paper 2. The ink-jet head 11 is mounted on the carriage 51 so as to reciprocate between the printing position A shown in FIG. 1 and a home position (not shown) deviated from the conveyance path 14 to the outside in the printer width direction. It is configured. The inkjet head 11 performs printing on the label paper 2 conveyed through the conveyance path 14 in a state where it is stopped at the printing position A. When printing is completed, the inkjet head 11 is retracted to the home position and stands by. During standby, a maintenance operation for preventing or eliminating clogging of the ink nozzles of the inkjet head 11 is performed.

  An ink cartridge mounting portion 52 is provided below the platen 12. The ink cartridge mounting unit 52 is mounted with ink cartridges that store inks of four colors, cyan, magenta, yellow, and black. When the ink cartridge is mounted in the ink cartridge mounting portion 52, an ink supply pump mechanism (not shown) is connected to the ink tank in the ink cartridge, and ink can be supplied to the inkjet head 11.

  The label paper 2 is drawn upward from the roll paper 3 toward the rear of the printer, is then stretched around the feeding roller 32, and is drawn obliquely downward toward the front of the printer via the feeding roller pair 30. Further, the label paper 2 is pulled out in the direction along the conveyance surface 16 of the paper guide 15 via the load roller 22, passes through between the pair of guide surfaces 20, 21 of the paper guide 15, and then the paper feed roller pair 40. Is disposed so as to pass through the platen surface 12a.

  When the label paper 2 is placed in the transport path 14, the printer 1 starts sucking the label paper 2 to the platen surface 12a and maintains this suction state. The printer 1 drives the paper feed roller 41 or the feed roller 32 to convey the label paper 2 in the forward direction D1 toward the front of the printer or in the reverse direction D2 opposite to the forward direction D1. The print start target position on the label 5 to be printed is positioned at the print position A.

  When a print command is supplied from the external device to the printer 1, the printer 1 feeds the label paper 2 in the forward direction D <b> 1 by the paper feed roller 41, and ink that ejects ink from the inkjet head 11. By performing the ejection operation in parallel, printing is performed on the label 5 passing through the printing position A. When printing is completed, the label paper 2 is further conveyed in the forward direction D1 by the paper feed roller 41, and the printed label 5 is exposed to the outside from the paper discharge port 13. As a result, the user can peel the label 5 from the mount 4.

  Thereafter, when a new print command is supplied from the external device to the printer 1, the printer 1 drives the feeding roller 32 to convey the label paper 2 in the reverse direction D <b> 2, and among the labels 5 of the label paper 2, The print start target position on the label 5 next to the printed label 5 is positioned at the print position A. After that, printing is performed on the label 5 by performing in parallel a paper feeding operation for transporting the label paper 2 in the forward direction D1 by the paper feeding roller 41 and an ink ejection operation for ejecting ink from the inkjet head 11. Then, the printed label 5 is exposed to the outside from the paper discharge port 13.

(Label paper transport operation)
FIG. 3 is a schematic block diagram of a control system for conveying the label paper 2. 4A is an explanatory diagram of a transport operation for transporting the label paper 2 in the forward direction D1, and FIG. 4B is an explanatory diagram of a transport operation for transporting the label paper 2 in the reverse direction D2.

  As shown in FIG. 3, the printer 1 includes a conveyance control unit 60 that controls conveyance of the label paper 2. A feed motor 31, a paper feed motor 43, a press roller moving motor 35, and a press roller moving motor 46 are connected to the output side of the transport control unit 60. The conveyance control unit 60 drives the feeding roller 32 by drivingly controlling the feeding motor 31. The conveyance control unit 60 drives and controls the presser roller moving motor 35 to drive the feed presser roller moving mechanism 34 to move the feed presser roller 33 between the nip position 33A and the release position 33B. Furthermore, the conveyance control unit 60 drives the paper feed roller 41 by drivingly controlling the paper feed motor 43. Further, the conveyance control unit 60 drives and controls the press roller moving motor 46 to drive the paper feed press roller moving mechanism 45 to move the paper feed press roller 42 between the nip position 42A and the release position 42B. .

  As shown in FIG. 4A, when the label sheet 2 is conveyed in the forward direction D1, the conveyance control unit 60 is a pair of paper feed rollers located on the downstream side of the guide surfaces 20 and 21 in the conveyance direction. 40 is set to the nip state, the feeding roller pair 30 positioned upstream in the transport direction is opened, and the label paper 2 is transported by the paper feed roller pair 40. More specifically, the paper feed press roller 42 of the paper feed roller pair 40 is moved to the nip position 42A, and the feed press roller 33 of the feed roller pair 30 is moved to the open position 33B. Then, the conveyance control unit 60 drives the paper feed roller 41 to convey the label paper 2.

  Here, since the paper feed roller pair 40 transports the label paper 2 while pulling it, tension is generated in the label paper 2 on the upstream side of the paper feed roller pair 40 in the transport direction. Further, when the roll paper 3 rolls in the roll paper loading chamber 10 as the label paper 2 is conveyed in the positive direction D1, the frictional force between the roll paper 3 and the roll paper loading chamber 10 or the roll paper. Tension is applied to the label paper 2 by the load F <b> 1 generated by the inertia force 3. As a result, when the label paper 2 is transported in the forward direction D1, the position of the label paper 2 on the transport surface 16 is stabilized, and the label paper 2 can be made to follow the guide surfaces 20 and 21. The occurrence of skew in the paper 2 can be prevented or suppressed. Further, the feeding roller pair 30 positioned on the upstream side in the transport direction of the guide surfaces 20 and 21 is in an open state in which a space is formed between the feeding roller 32 and the feeding and pressing roller 33, and the upstream in the transport direction. The influence of the rotation of the feeding roller pair 30 on the side on the conveyance of the label paper 2 is small. As a result, the label paper 2 is not distorted due to the difference in rotation amount between the paper feed roller pair 40 and the feed roller pair 30 and the position of the label paper 2 on the transport surface 16 is not unstable. 2 can be conveyed along the guide surfaces 20 and 21, and the occurrence of skew can be prevented or suppressed.

  When the label paper 2 is transported in the forward direction D1, the feeding roller 32 is brought into a state where it can rotate together with the transport of the label paper 2. Alternatively, the feeding roller 32 is driven at a rotation speed or less at which the label paper 2 can be conveyed by the same conveyance amount as the conveyance amount of the label paper 2 by the paper feed roller pair 40.

  Next, as illustrated in FIG. 4B, when the label paper 2 is transported in the reverse direction D <b> 2, the transport controller 60 feeds the guide surfaces 20, 21 positioned downstream in the transport direction. The pair of rollers 30 is set to the nip state, the pair of paper feed rollers 40 located on the upstream side in the transport direction is opened, and the label paper 2 is transported by the feed roller pair 30. More specifically, the feed press roller 33 of the feed roller pair 30 is moved to the nip position 33A, and the paper feed press roller 42 of the paper feed roller pair 40 is moved to the open position 42B. Then, the conveyance control unit 60 drives the feeding roller 32 to convey the label paper 2.

  Here, since the feeding roller pair 30 conveys the label sheet 2 while pulling, tension is generated in the label sheet 2 on the upstream side in the conveying direction of the feeding roller pair 30. Further, the platen 12 sucking the label paper 2 upstream of the guide surfaces 20 and 21 in the conveying direction applies tension to the label paper 2 by the load F2 caused by suction. As a result, when the label paper 2 is transported in the reverse direction D2, the position of the label paper 2 on the transport surface 16 is stabilized, and the label paper 2 can be made to follow the guide surfaces 20 and 21. The occurrence of skew in the paper 2 can be prevented or suppressed. Further, the pair of paper feed rollers 40 located on the upstream side in the transport direction of the guide surfaces 20 and 21 is in an open state in which a space is formed between the paper feed roller 41 and the paper feed presser roller 42, The rotation of the pair of paper feed rollers 40 on the upstream side in the direction has little influence on the conveyance of the label paper 2. As a result, the label paper 2 is not distorted due to the difference in rotation amount between the paper feed roller pair 40 and the feed roller pair 30 and the position of the label paper 2 on the transport surface 16 is not unstable. The medium can be conveyed along the guide surfaces 20 and 21, and the occurrence of skew can be prevented or suppressed.

  When the label paper 2 is transported in the reverse direction D2, the paper feed roller 41 is set in a state where it can rotate together with the transport of the label paper 2.

(Other embodiments)
In the above example, the pair of guide surfaces 20 and 21 are provided as the guide surfaces. However, by providing any one of the guide surfaces, it is possible to suppress the skew of the label paper 2.

  Further, in the above example, the load roller 22 is provided at the rear end portion of the frame portion 17 of the paper guide 15, but in the transport path 14, the paper feed roller pair 40 from the feed roller pair 30 through the paper guide 15. The load roller 22 can be omitted in the case where the conveyance path portion leading to is formed linearly. That is, even if the load roller 22 is omitted, the label paper 2 can be transported along the transport surface 16 of the paper guide 15. Further, the print medium that can be used in the printer 1 is not limited to the label paper 2, and a long recording paper fed from a roll paper can be used.

1 .. Printer 2. Label paper (sheet medium / recording paper) 3. Roll paper 4 .. Mount 5. Label 10. Roll paper loading chamber (roll paper loading section) 11. ..Inkjet head (printing head), 12 ... Platen surface, 12a ... Platen surface, 13 ... Paper discharge port, 14 ... Transport path, 15 ... Paper guide, 16 ... Transport surface, 17 ... Frame section 18 · 19 ·· Guide part, 20 · 21 ·· Guide surface, 22 ·· Load roller, 30 ·· Feed roller pair (drive roller pair), 31 ·· Feed motor, 32 ·· Feed roller, 33 ··· Feeding presser roller, 33A ... Nipping position, 33B ... Opening position, 34 ... Feeding presser roller moving mechanism (roller pair displacement mechanism), 35 ... Pressing roller moving motor, 40 ... Paper feed roller pair (drive roller pair) 41.. Paper feed roller 42.. Paper feed press roller 42 A ... Nip position 42 B ... Open position 43 ... Paper feed motor 44 ... Reduction mechanism 45 .. Paper feed presser roller moving mechanism (roller pair displacement mechanism), 46 .. Presser roller moving motor, 50 .. Suction port, 51 .. Carriage, 52 .. Ink cartridge mounting unit, 60 .. Transport control unit A, Printing position, D1, Forward direction, D2, Reverse direction

Claims (5)

In a medium transport apparatus that transports a long sheet-shaped medium fed out of roll paper in the forward direction and the reverse direction along the transport path,
A guide surface that contacts the edge in the width direction of the sheet-shaped medium from a direction orthogonal to the conveying direction and guides the sheet-shaped medium in the conveying direction;
Two drive roller pairs arranged on both sides of the guide surface in the transport direction;
A roller pair displacement mechanism for displacing each drive roller pair between a nip state in which the sheet-like medium is nipped and an open state in which the sheet-like medium is opened;
When transporting the sheet-like medium in the forward direction and the reverse direction, one of the drive roller pairs positioned on the downstream side in the transport direction is brought into a nip state and the other pair of drive rollers positioned on the upstream side A conveyance control unit that conveys the sheet-like medium by driving one of the driving roller pairs located on the downstream side,
A medium conveying apparatus comprising: In claim 1,
A medium transporting device comprising a pair of guide surfaces capable of coming into contact with both edges in the width direction of the sheet-like medium as the guide surfaces. The medium carrying device according to claim 1 or 2,
The sheet-like medium is a recording paper,
The conveyance path extends from a roll paper loading unit on which the roll paper is loaded in a rollable manner via a print position by a print head,
The two driving roller pairs and the guide surface are located between the roll paper loading unit and the printing position. In claim 3,
The printing position is defined by a platen,
The platen is a suction platen that sucks air from a suction port formed on the platen surface and sucks the recording paper conveyed through the printing position so as not to float from the platen surface, and at least the recording paper is A printer that applies tension to the recording paper by suction when transported in a direction from the printing position toward the roll paper loading unit. In claim 3 or 4,
The printer, wherein the print head is an inkjet head, and performs printing on the recording paper transported through the print position while stopped at the print position.

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