Printing device, control method for printing device

Abstract

To correct skew of a medium to be conveyed.SOLUTION: A printing device comprises: a pair of first conveying rollers capable of conveying a medium while nipping the medium by a first nip part; a pair of second conveying rollers which is arranged downstream of the pair of first conveying rollers and is capable of conveying the medium while nipping the medium by a second nip part; and a device which is arranged between the pair of first conveying rollers and the pair of second conveying rollers in a conveying path of the medium and can nip the medium by a third nip part. The third nip part has a nipping force weaker than the first nip part. In a state that the medium is nipped by the first nip part, the tip of the medium follows the second nip part, and then the nip of the first nip part is released.SELECTED DRAWING: Figure 7C

Description

Technical Field

[0001] The present invention relates to a printing apparatus and a method for controlling the printing apparatus.

Background Art

[0002] Conventionally, as shown in Patent Document 1, there is known an image forming apparatus that feeds sheets one by one with a feed roller and corrects skewing by abutting a skewed sheet against a nip portion of a pair of correction roller pairs.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the image forming apparatus described in Patent Document 1, the leading edge of the sheet is made to follow the nip portion of the pair of correction rollers, and the skewing is corrected by the sheet sliding in the conveyance path in a state following the nip portion. However, in a configuration where the sheet is nipped by, for example, an imaging device or the like on the conveyance path between the feed roller and the pair of correction rollers, when the leading edge of the sheet is made to follow the nip portion of the pair of correction rollers, the nip force by the imaging device or the like makes it difficult for the sheet to slide in the conveyance path, a bend is formed in the sheet, and that state is maintained. If the sheet is conveyed from the pair of correction rollers in this state, there is a problem that the generated bend is gradually released and the sheet skews again. Also, in a sheet with relatively high stiffness, the sheet itself does not bend. Therefore, in order to make the sheet tip follow the correction roller pair, it is necessary to slide the sheet within the conveyance path. However, if the sheet is nipped by the imaging device, the sheet cannot be slid within the conveyance path, and the tip of the sheet cannot follow the correction roller pair. That is, there is a problem that skew correction cannot be performed.

Means for Solving the Problem

[0005] The printing apparatus includes a first conveyance roller pair capable of conveying the medium while nipping the medium at a first nip portion, a second conveyance roller pair disposed downstream of the first conveyance roller pair and capable of conveying the medium while nipping the medium at a second nip portion, and a device disposed between the first conveyance roller pair and the second conveyance roller pair in the conveyance path of the medium and capable of nipping the medium at a third nip portion. The third nip portion has a weaker nip force than the first nip portion. With the medium nipped at the first nip portion, the tip of the medium is made to follow the second nip portion, and then the nip of the first nip portion is released.

[0006] The printing apparatus includes a first conveyance roller pair capable of conveying the medium while nipping the medium at a first nip portion, a second conveyance roller pair disposed downstream of the first conveyance roller pair and capable of conveying the medium while nipping the medium at a second nip portion, and a device disposed between the first conveyance roller pair and the second conveyance roller pair in the conveyance path of the medium and capable of nipping the medium at a third nip portion. The third nip portion has a weaker nip force than the first nip portion. With the tip of the medium nipped at the second nip portion, the medium is conveyed downstream, and then, with the nip of the first nip portion released, the medium is conveyed so that the tip of the medium is located upstream of the second nip portion.

[0007] A control method for a printing apparatus includes a first pair of conveying rollers capable of conveying a medium while nipping the medium at a first nip portion, a second pair of conveying rollers disposed downstream of the first pair of conveying rollers and capable of conveying the medium while nipping the medium at a second nip portion, and a device disposed between the first pair of conveying rollers and the second pair of conveying rollers in the conveyance path of the medium and capable of nipping the medium at a third nip portion. The third nip portion is configured to have a weaker nip force than the first nip portion. The control method for the printing apparatus is such that, with the medium nipped at the first nip portion, the leading end of the medium is made to follow the second nip portion, and then the nip of the first nip portion is released.

[0008] A control method for a printing apparatus includes a first pair of conveying rollers capable of conveying a medium while nipping the medium at a first nip portion, a second pair of conveying rollers disposed downstream of the first pair of conveying rollers and capable of conveying the medium while nipping the medium at a second nip portion, and a device disposed between the first pair of conveying rollers and the second pair of conveying rollers in the conveyance path of the medium and capable of nipping the medium at a third nip portion. The third nip portion is configured to have a weaker nip force than the first nip portion. The control method for the printing apparatus is such that the medium is conveyed downstream with the leading end of the medium nipped at the second nip portion, and then the medium is conveyed so that the leading end of the medium is located upstream of the second nip portion with the nip of the first nip portion released.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7A

Figure 7B

Figure 7C

Figure 7D

Figure 8A

Figure 8B

Figure 9

DETAILED DESCRIPTION OF THE INVENTION

[0010] 1. First Embodiment First, the configuration of the printing apparatus 11 will be described. The printing apparatus 11 of the present embodiment is an inkjet apparatus that discharges ink as a liquid onto a medium M for printing. The medium M is, for example, a long roll paper R wound in a roll shape or a single-sheet paper.

[0011] In the following drawings, the printing apparatus 11 is placed on a horizontal plane. The front-rear direction of the printing apparatus 11 is along the Y-axis, the left-right direction (or width direction) is along the X-axis, and the vertical direction (up-down direction) with respect to the horizontal plane is along the Z-axis. Also, the +Y direction is the front direction, the -Y direction is the rear direction, the +X direction is the right direction, the -X direction is the left direction, the +Z direction is the up direction, and the -Z direction is the down direction.

[0012] As shown in FIGS. 1, 2, and 3, the printing apparatus 11 includes a rectangular parallelepiped housing 12 and a main body frame 16 that supports each part of the printing apparatus 11. The housing 12 has an opening 13 that opens to the front. Further, a discharge unit 28 having a discharge port 14 through which the printed and cut medium M is discharged is installed in the housing 12.

[0013] The printing apparatus 11 includes a storage unit 40 that stores the roll paper R and feeds out the stored roll paper R. The storage unit 40 is installed so as to be pullable forward from the housing 12 through the opening 13. When the storage unit 40 is stored in the housing 12, it includes a front plate portion 42 that forms part of the exterior of the printing apparatus 11 and a pair of support walls 43 that rotatably support the roll paper R.

[0014] Below the discharge unit 28, there is provided a box-shaped cutting waste storage unit 80 that stores the cutting waste of the medium M generated by cutting by the cutting unit 27. The cutting waste storage unit 80 is detachably installed on the front surface of the housing 12 in the forward direction of the roll paper R. The cutting waste storage unit 80 closes the opening 13 when attached to the housing 12. When the cutting waste storage unit 80 is attached to the housing 12, it includes an outer wall 81 that forms part of the exterior of the printing apparatus 11.

[0015] When the cutting waste storage unit 80 is removed from the housing 12, the storage unit 40 becomes pullable from the housing 12. With the storage unit 40 pulled out from the housing 12, the roll paper R can be replaced.

[0016] In front of the housing 12, an operation unit 15 for operating the printing apparatus 11 is provided. The operation unit 15 is a horizontally long panel in the direction along the X-axis, and includes a power button 15a that is operated when turning on or off the printing apparatus 11, input buttons 15b through which various operation information can be input, and an operation panel 15c provided with displays such as the operation state of the printing apparatus 11 and operation buttons of the printing apparatus 11. The operation panel 15c is a touch panel. Further, a speaker 15d that emits sound outward is provided.

[0017] As shown in FIG. 3, the printing apparatus 11 includes a conveyance path 30 (indicated by a two-dot chain line in the figure) along which a medium M is conveyed. The printing apparatus 11 includes a conveyance unit 31 that conveys the medium M along the conveyance path 30, a printing unit 20 that performs printing on the medium M, and a cutting unit 27 that cuts the medium M.

[0018] The printing unit 20 performs printing on the medium M conveyed from the storage unit 40. The printing unit 20 includes a head 22 having nozzles 23 that eject ink toward the medium M, and a carriage 21 on which the head 22 is mounted. The carriage 21 is supported by a guide frame 100 extending along the X-axis and a guide shaft 24 attached to the guide frame 100 and extending along the X-axis. The carriage 21 is movable along the guide shaft 24 by a drive source such as a motor. That is, the carriage 21 is reciprocally movable in a direction along the X-axis. A support unit 25 that supports the medium M is provided at a position facing the head 22.

[0019] The head 22 performs printing on the medium M supported by the support unit 25 by ejecting ink while reciprocally moving in the width direction of the medium M together with the carriage 21. In the present embodiment, as the printing unit 20, a serial head system in which the head 22 reciprocally moves in the width direction is exemplified, but a printing unit of a line head system in which the head 22 extends in the width direction and is fixedly arranged may also be used.

[0020] The conveyance path 30 is a space in which the medium M can move and is composed of a plurality of members. The conveyance path 30 extends from a storage unit 40 located at the uppermost stream that feeds out a roll paper R to a discharge unit 28 (discharge port 14) located at the lowermost stream. The printing unit 20, the support unit 25, and the like are arranged on the conveyance path 30.

[0021] The cutting part 27 is located downstream of the support part 25 and upstream of the discharge port 14. The cutting part 27 of the present embodiment includes a movable blade 27a that can reciprocate in the width direction (left - right direction), and a fixed blade 27b that does not move. The movable blade 27a is provided above the conveyance path 30, and the fixed blade 27b is provided below the conveyance path 30. The cutting part 27 cuts the medium M across the width direction at the cutting position. The cutting position is the position of the cutting edge of the fixed blade 27b.

[0022] The conveyance path 30 of the present embodiment includes a first path 30a through which the medium M fed out from the roll paper R is conveyed from the upstream side in the conveyance direction of the medium M, a curved path 30b through which the medium M is conveyed while being curved, a second path 30c (corresponding to the conveyance path) through which the medium M is conveyed toward the head 22 (support part 25), and a third path 30d through which the medium M is conveyed from the downstream of the support part 25 toward the discharge part 28.

[0023] Furthermore, the printing apparatus 11 of the present embodiment includes a reversing path 30e. The reversing path 30e is a passage connecting a branching point P1 that branches from the second path 30c and a merging point P2 that merges into the first path 30a. In the conveyance direction of the medium M conveyed through the curved path 30b, the merging point P2 is located upstream of the branching point P1. That is, the reversing path 30e merges upstream of the curved path 30b. The reversing path 30e is a path for reversing the single - sheet - like medium M and performing printing on both sides of the medium M.

[0024] The conveyance unit 31 conveys the medium M along the conveyance path 30 that reaches the cutting part 27 and the discharge part 28 from the storage part 40 via the printing part 20. The conveyance unit 31 includes a supply roller pair 32 provided on the first path 30a, a first conveyance roller pair 33 that forms the curved path 30b, and a second conveyance roller pair 35 disposed downstream of the first conveyance roller pair 33. The first conveying roller pair 33 is composed of an intermediate roller 33a and a driven roller 34a arranged along the outer peripheral surface of the intermediate roller 33a of the curved path 30b. The driven roller 34a is arranged at a position facing the intermediate roller 33a and rotates following the rotation of the intermediate roller 33a. In this embodiment, a plurality (three in this embodiment) of driven rollers 34a are provided. Thereby, the medium M can be smoothly conveyed along the curved path 30b. The second conveying roller pair 35 is composed of an upstream conveying drive roller 35a and an upstream conveying driven roller 35b arranged at a position facing the upstream conveying drive roller 35a and rotating following the rotation of the upstream conveying drive roller 35a.

[0025] The conveying unit 31 further includes a downstream first conveying roller pair 36, a downstream second conveying roller pair 37, and a downstream third conveying roller pair 38 on the third path 30d. The downstream second conveying roller pair 37 is located upstream of the cutting unit 27. The downstream third conveying roller pair 38 is located downstream of the cutting unit 27.

[0026] Here, the configuration of the storage unit 40 will be described. The storage unit 40 is rotatably supported via a support shaft 41 around which the roll paper R extends in the width direction of the housing 12. The support shaft 41 is configured to be rotatable in both forward and reverse directions. Therefore, the roll paper R is rotatably driven in both forward and reverse directions via the support shaft 41. Further, the storage unit 40 is provided with a roll paper conveying path 50 for conveying the medium M fed out from the roll paper R toward the first path 30a.

[0027] The roll paper conveying path 50 extends downward from the front side of the roll paper R supported via the support shaft 41, then bends rearward, wraps around the lower and rear directions of the roll paper R, and extends upward to a position higher than the roll paper R and reaches the first path 30a.

[0028] The roll paper conveyance path 50 has a bending portion 50a that bends substantially at a right angle at its upstream end, that is, in a diagonally downward direction in the forward direction of the roll paper R in the roll paper conveyance path 50. A decal mechanism 51 for performing decal to correct the curling of the medium M fed out from the roll paper R is provided on the downstream side of the bending portion 50a in the roll paper conveyance path 50.

[0029] On the downstream side of the decal mechanism 51 in the roll paper conveyance path 50, a pair of roll paper conveyance rollers 56 that apply a conveyance force to the roll paper R are installed at appropriate intervals. When the pair of roll paper conveyance rollers 56 is rotationally driven, the medium M is fed out from the roll paper R and conveyed to the first path 30a.

[0030] The pair of roll paper conveyance rollers 56, the supply roller pair 32, the first conveyance roller pair 33, the second conveyance roller pair 35, the downstream first conveyance roller pair 36, the downstream second conveyance roller pair 37, and the downstream third conveyance roller pair 38 convey the medium M by rotating while sandwiching the medium M.

[0031] When each roller of the conveyance unit 31 is driven to rotate forward, the medium M is conveyed from upstream to downstream, and when driven to rotate in reverse, the medium M is conveyed from downstream to upstream. In the present embodiment, along the conveyance path 30, the direction toward the downstream is referred to as the downstream direction D1, and the direction opposite to the downstream direction D1 is referred to as the upstream direction D2.

[0032] The printing device 11 includes a heating unit 60 that heats the conveyed medium M. The heating unit 60 is positioned to face the intermediate roller 33a installed in the curved path 30b, and is installed immediately downstream of the lowermost downstream driven roller 34a among the three driven rollers 34a. The heating unit 60 is configured to correct the curling of the medium M. The heating unit 60 of the present embodiment is composed of a heater 61 that generates heat and a fan 62 that blows the heat of the heated heater 61 onto the medium M.

[0033] Further, a device is arranged on a conveyance path 30 that extends from a storage unit 40, passes through a printing unit 20, and reaches a discharge unit 28. The device is used for purposes other than conveying the medium M. The device in this embodiment is an imaging device 90. The imaging device 90 is a device capable of reading information on the medium M. The imaging device 90 is arranged between a first conveyance roller pair 33 and a second conveyance roller pair 35 in a second path 30c. The second path 30c is inclined downward from the upper end of the curved path 30b toward a discharge surface (the -Z direction end surface of the head 22) where ink is discharged from the head 22 of the printing unit 20. And at least a part of the imaging device 90 is arranged between the upper end of the curved path 30b and the discharge surface of the head 22 in the height direction. In this embodiment, the imaging device 90 is arranged between the upper end of the curved path 30b and the discharge surface of the head 22. That is, the imaging device 90 is arranged between an upstream conveyance drive roller 35a and an intermediate roller 33a in the second path 30c. Thereby, the dimensional size of the printing apparatus 11 in the height direction can be suppressed. Also, the printing apparatus 11 can be downsized.

[0034] The imaging device 90 is capable of imaging the printed medium M. For example, the imaging device 90 reads a test pattern or the like printed by the printing unit 20. The imaging device 90 can image an area in the width direction of the medium M. Also, since the imaging device 90 is arranged at a position farther from the discharge unit 28 (discharge port 14), the influence of external disturbance light is small, and the imaging function can be ensured.

[0035] As shown in FIG. 4, the imaging device 90 includes a contact image sensor (CIS) module 900. The CIS module 900 includes a light source such as an LED that irradiates light on the medium M, a light receiving element such as a CMOS sensor that receives reflected light from the medium M, and a contact glass 910 that contacts the medium M. The medium M is conveyed while contacting the transmission surface of the contact glass 910. The light source irradiates light on the medium M through the contact glass 910, and the light receiving element reads the reflected light from the medium M.

[0036] In the CIS module 900 of the present embodiment, it is arranged to extend in the X-axis direction corresponding to the width dimension of the medium M. The CIS module 900 can read in a batch the range corresponding to the width dimension of the medium M.

[0037] Further, the imaging device 90 includes a pressing portion 950 that biases the medium M in a direction of pressing it against the contact glass 910 of the CIS module 900. The pressing portion 950 is provided at a position facing the contact glass 910.

[0038] The pressing portion 950 has a pressing plate 951 that can contact the medium M and a pressing spring 952 that biases the pressing plate 951 in a direction approaching the contact glass 910. The pressing spring 952 is connected to a fixing member 953. The surface of the pressing plate 951 that contacts the medium M is a flat surface. The pressing plate 951 is arranged to extend in the X-axis direction. The pressing plate 951 faces the transmission surface of the contact glass 910 of the CIS module 900 with the second path 30c therebetween. In the imaging device 90, a third nip portion Np3 that sandwiches the medium M between the contact glass 910 and the pressing plate 951 is formed. The third nip portion Np3 will be described later.

[0039] In the imaging device 90, for example, a test pattern is imaged. The test pattern is a pattern composed of a set of a plurality of straight lines corresponding to each nozzle 23 by discharging ink from the nozzles 23 of the printing unit 20. The discharge state of the nozzles 23 can be confirmed by the printed test pattern. In the present embodiment, the imaging device 90 acquires image data of the test pattern, and based on the acquired image data, the control unit 58 determines whether the discharge state of the nozzles 23 is good or not. When the control unit 58 determines that the discharge state of the nozzles 23 is good, a printing process is executed. On the other hand, when it is determined that the discharge state of the nozzles 23 is not good due to nozzle dropout (dot dropout) or the like, maintenance processes such as cleaning can be executed.

[0040] Further, the printing apparatus 11 of the present embodiment is configured to be able to print on a single-sheet medium M. Also, double-sided printing is possible for the single-sheet medium M. The printing apparatus 11 houses a cassette 221 for accommodating the medium M on the outer surface of the housing 12, and a housing and conveyance body 200 capable of conveying the medium M is set.

[0041] The housing and conveyance body 200 has a feeding unit 222 that conveys the medium M accommodated in the cassette 221 toward the curved path 30b. The feeding unit 222 includes a pickup roller 227 that feeds out the uppermost medium M among the media M accommodated in the cassette 221 in a stacked state, a separation roller pair 228 that separates the media M fed out by the pickup roller 227 one by one, and a conveyance roller pair 229 that conveys the medium M along the single-sheet conveyance path 217 toward the curved path 30b.

[0042] At the downstream end of the single-sheet conveyance path 217, a communication path 230 communicating with the curved path 30b is provided. The medium M conveyed from the cassette 221 is conveyed along the single-sheet conveyance path 217 and merges into the curved path 30b through the communication path 230. The medium M that has merged into the curved path 30b is conveyed toward the printing unit 20 side by the conveyance unit 31. Also, the medium M printed by the printing unit 20 can be conveyed in the upstream direction D2, the front and back of the medium M can be reversed through the reversing path 30e, and the medium M can be conveyed in the downstream direction D1 and conveyed to the printing unit 20 to print on the opposite side. Thereby, double-sided printing becomes possible.

[0043] When printing on the single-sheet medium M, the imaging device 90 can read an image formed on the medium M. For example, when the medium M is a postcard, information such as a frame for writing a postal code printed on the postcard and the name and address can be read. Thereby, detection of the front and back surfaces of the medium M and the orientation of the medium M can be detected.

[0044] Next, the skew correction mechanism 190 in the printing apparatus 11 will be described. As shown in FIG. 5, the printing apparatus 11 includes a skew correction mechanism 190. The skew correction mechanism 190 is a mechanism that performs a skew correction operation on the medium M. The skew correction operation is an operation of aligning the extending direction of the leading end Ma of the medium M with the extending direction of the second conveying roller pair 35 before printing is performed on the medium M in order to suppress the inclination of the printing position on the medium M with respect to the leading end Ma of the medium M. The extending direction of the second conveying roller pair 35 is the width direction of the printing apparatus 11 (the direction along the X axis), that is, the same direction as the moving direction of the carriage. Therefore, when the extending direction of the leading end Ma of the medium M coincides with the extending direction of the second conveying roller pair 35, the extending direction of the leading end Ma of the medium M coincides with the width direction of the printing apparatus 11. When the medium M is conveyed by the second conveying roller pair 35 in this state, the medium M in a state where the skew is corrected can be conveyed to the printing unit 20.

[0045] The skew correction mechanism 190 includes a first conveying roller pair 33, a second conveying roller pair 35, and an imaging device 90. The first conveying roller pair 33 includes an intermediate roller 33a as a driving roller and a driven roller 34a. The first conveying roller pair 33 forms a first nip portion Np1 that nips the medium M by the intermediate roller 33a and the driven roller 34a. In the first nip portion Np1, a nip force for sandwiching the medium M is applied between the driven roller 34a and the intermediate roller 33a. Then, the medium M can be conveyed by the nip force in the first nip portion Np1.

[0046] The second conveying roller pair 35 includes an upstream conveying driving roller 35a and an upstream conveying driven roller 35b. The second conveying roller pair 35 forms a second nip portion Np2 that nips the medium M by the upstream conveying driving roller 35a and the upstream conveying driven roller 35b. In the second nip portion Np2, a nip force for sandwiching the medium M is applied between the upstream conveying driven roller 35b and the upstream conveying driving roller 35a. Then, the medium M can be conveyed by the nip force in the second nip portion Np2.

[0047] The first pair of conveying rollers 33 conveys the medium M in the downstream direction D1 as the conveying direction by rotating the intermediate roller 33a in the forward rotation direction W1. The second pair of conveying rollers 35 is disposed downstream of the first pair of conveying rollers 33 in the conveying direction, and conveys the medium M in the downstream direction D1 as the conveying direction by rotating the upstream conveying drive roller 35a in the forward rotation direction W1. Note that the second pair of conveying rollers 35 is configured to be able to convey the medium M also in the upstream direction D2 as the conveying direction by rotating the upstream conveying drive roller 35a in the reverse rotation direction W2.

[0048] Here, the printing apparatus 11 of the present embodiment includes a first driving device 335 that drives the upstream conveying drive roller 35a, and a second driving device 334 that drives the intermediate roller 33a (FIG. 6). The first driving device 335 and the second driving device 334 are, for example, motors. An electromagnetic clutch mechanism 333 is provided on the intermediate roller 33a. Specifically, it is configured such that the power from the second driving device 334 can be transmitted via the electromagnetic clutch mechanism 333. A coil is disposed in the electromagnetic clutch mechanism 333. For example, by energizing the coil, the power of the second driving device 334 can be transmitted to the intermediate roller 33a using the electromagnetic force generated, and the intermediate roller 33a can be rotated. On the other hand, when the energization of the coil is stopped, no electromagnetic force is generated, the power from the second driving device 334 to the intermediate roller 33a is cut off, and the intermediate roller 33a does not rotate driven, and becomes a state where it can freely rotate together with the driven roller 34a.

[0049] The imaging device 90 is disposed between the first conveyance roller pair 33 and the second conveyance roller pair 35 in the second path 30c. Then, a third nip portion Np3 for nipping the medium M by the contact glass 910 and the pressing plate 951 is formed. In the third nip portion Np3, a nip force for sandwiching and holding the medium M is applied between the contact glass 910 and the pressing plate 951. Note that the nip force of the third nip portion Np3 is weaker than the nip forces of the first nip portion Np1 and the second nip portion Np2. For example, the nip force of the third nip portion Np3 is about 50% of the nip forces of the first nip portion Np1 and the second nip portion Np2. That is, the third nip portion Np3 of the imaging device 90 has a nip force sufficient to hold the medium M in a state where information on the medium M can be read by the CIS module 900, and does not contribute to the conveyance force of the medium M. Further, the skew correction mechanism 190 has a conveyance guide surface 94 for guiding the medium M between the first conveyance roller pair 33 and the second conveyance roller pair 35 in the second path 30c.

[0050] Next, the control configuration of the printing device 11 will be described. As shown in FIG. 6, the printing device 11 includes a control unit 58 that controls various operations executed by the printing device 11. The control unit 58 includes a CPU 581, a memory 582, a control circuit 583, and an I / F (interface) 584. The CPU 581 is an arithmetic processing unit. The memory 582 is a storage device that secures an area or a work area for storing the program of the CPU 581 and has storage elements such as a RAM and an EEPROM. When print data or the like is acquired from an external device such as an information processing terminal via the I / F 584, the CPU 581 performs arithmetic operations based on the program and controls each drive unit or the like via the control circuit 583. Note that the supply roller pair 32, the intermediate roller 33a, the second conveyance roller pair 35, the downstream first conveyance roller pair 36, the downstream second conveyance roller pair 37, the downstream third conveyance roller pair 38, the roll paper conveyance roller pair 56, and the conveyance roller pair 229 that constitute the conveyance unit 31 are each configured to be drive controllable.

[0051] Next, a control method for the printing apparatus 11 will be described. Specifically, a control method for the skew correction mechanism 190 will be described. In this embodiment, a skew correction method for a single-sheet medium M will be described.

[0052] As shown in FIG. 7A, the control unit 58 abuts the leading end Ma of the medium M against the second nip portion Np2 of the stopped second conveying roller pair 35. Specifically, with the second conveying roller pair 35 stopped, the intermediate roller 33a is rotated in the forward rotation direction W1, and the medium M is conveyed in the downstream direction D1.

[0053] Next, as shown in FIG. 7B, with the leading end Ma of the medium M abutted against the second nip portion Np2, the control unit 58 rotates the intermediate roller 33a in the forward rotation direction W1 and further conveys the medium M in the downstream direction D1. Thereby, by bending the medium M between the first nip portion Np1 and the second nip portion Np2, the leading end Ma of the medium M can be made to follow the second nip portion Np2. At this time, a bend is formed in the medium M between the second nip portion Np2 and the third nip portion Np3. The bend of the medium M is formed, for example, in a convex state downward. Note that a bend formed in a convex state upward may be formed.

[0054] For example, when the leading end Ma of the medium M is skewed with respect to the width direction and the leading end Ma on the -X direction side of the leading end Ma of the medium M is conveyed first, first, the portion on the -X direction side of the leading end Ma abuts against the second nip portion Np2. In this state, when the first conveying roller pair 33 further conveys the medium M in the downstream direction D1, a bend is formed in the medium M between the first nip portion Np1 and the second nip portion Np2 on the -X direction side, and the portion on the +X direction side of the leading end Ma abuts against the second nip portion Np2. Then, a bend is also formed in the medium M between the first nip portion Np1 and the second nip portion Np2 on the +X direction side. That is, by forming a bend in the medium M between the first nip portion Np1 and the second nip portion Np2, the medium M is in a state where the leading end Ma of the medium M follows the second nip portion Np2. Thereby, since the extending direction of the leading end Ma of the medium M coincides with the width direction X of the printing apparatus 11, the skew of the leading end Ma of the medium M is corrected. Here, when the tip Ma of the medium M hits the second nip portion Np2, bending of the medium M occurs in the vicinity of the second nip portion Np2, and the bending of the medium M spreads upstream. Here, in the present embodiment, a third nip portion Np3 in the imaging device 90 is disposed between the first nip portion Np1 and the second nip portion Np2. For this reason, the bending of the medium M in the vicinity of the second nip portion Np2 is obstructed by the third nip portion Np3, and the diffusion of the bending of the medium M upstream of the third nip portion Np3 is suppressed. For this reason, bending is formed in the medium M between the second nip portion Np2 and the third nip portion Np3.

[0055] Note that the conveyance amount for conveying the medium M in the downstream direction D1 with the tip Ma of the medium M abutted against the second nip portion Np2 can be set as appropriate. For example, it can be set as appropriate according to the form such as the rigidity of the medium M. Thereby, bending with a predetermined bending amount suitable for the medium M can be formed. Further, the control of the conveyance amount of the medium M is executed by detecting the position of the tip Ma of the medium M. Medium detection sensors (not shown) for detecting the presence or absence of the medium M are disposed at a plurality of locations in the conveyance path 30. The medium detection sensors always output information on the presence or absence of the detected medium M to the control unit 58. Therefore, the control unit 58 can obtain passing information of the tip Ma of the medium M at the detection positions of the medium detection sensors.

[0056] Next, as shown in FIG. 7C, the control unit 58 releases the nip of the first nip portion Np1. The release of the nip of the first nip portion Np1 is performed by making the intermediate roller 33a constituting the first conveyance roller pair 33 freely rotatable. Note that the release of the nip force at the first nip portion Np1 does not have to be a state where the nip force is zero, and may be a relaxed state in which the bending of the medium M is released. In the release of the nip of the first nip portion Np1 in the present embodiment, the energization of the coil of the electromagnetic clutch mechanism 333 is stopped. Thereby, the power from the second drive device 334 to the intermediate roller 33a is cut off, the intermediate roller 33a does not rotate drivenly, and becomes a freely rotatable state.

[0057] The leading end Ma of the medium M follows the second nip portion Np2, and when the nip of the first nip portion Np1 is released in a state where a bend of the medium M is formed between the second nip portion Np2 and the third nip portion Np3, the bend of the medium M is gradually released upstream via the third nip portion Np3. That is, the nip force of the third nip portion Np3 is relatively weak, and in a state where the medium M is sandwiched between the contact glass 910 and the pressing plate 951, the bend of the medium M is released toward the first nip portion Np1 side via the third nip portion Np3. Specifically, the bend of the medium M is smoothly released by the medium M sliding in the region between the contact glass 910 and the pressing plate 951. As a result, the bend of the medium M is released between the first nip portion Np1 and the second nip portion Np2. Further, by providing the third nip portion Np3 between the first nip portion Np1 and the second nip portion Np2, when the nip of the first nip portion Np1 is released, the medium M is repelled toward the first conveying roller pair 33 side starting from the second nip portion Np2 by the repulsive force of the bend of the medium M, so-called kicking is suppressed, and the skew correction state of the medium M is maintained. In addition, by releasing the bend of the medium M, it is possible to suppress the surface of the medium M from being conveyed while rubbing against the conveying guide surface 94.

[0058] Next, as shown in FIG. 7D, the control unit 58 rotates the intermediate roller 33a and the upstream conveying drive roller 35a in the forward rotation direction W1, and conveys the medium M in the downstream direction D1 by the first conveying roller pair 33 and the second conveying roller pair 35. The leading end Ma of the medium M follows the second nip portion Np2, and the medium M is conveyed downstream in a state where the bend between the first nip portion Np1 and the second nip portion Np2 is released. Since the leading end Ma of the medium M follows the second nip portion Np2, when the second conveying roller pair 35 rotates in the forward rotation direction W1, the leading end Ma of the medium M is nipped by the second nip portion Np2 in a state where the skew of the leading end Ma of the medium M is corrected. By conveying the medium M in the downstream direction D1 in this state, the medium M in a state where the skew is corrected can be conveyed to the printing unit 20.

[0059] As described above, according to the present embodiment, since the third nip portion Np3 is disposed between the first nip portion Np1 and the second nip portion Np2, the bending of the medium M can be gradually released by utilizing the nip force of the third nip portion Np3. Further, the nip force of the third nip portion Np3 suppresses the kicking of the medium M, causes the leading end Ma of the medium M to follow the second nip portion Np2, and can reliably maintain the corrected state of the skew of the medium M. Further, since the imaging device 90 is disposed between the first nip portion Np1 and the second nip portion Np2, miniaturization of the printing device 11 and a flexible layout within the printing device 11 can be achieved. Note that the control unit 58 can also execute the skew correction operation by the skew correction mechanism 190 for the roll paper R fed out from the storage unit 40 in the same manner as described above.

[0060] 2. Second Embodiment Next, a second embodiment will be described. Note that only the control method is different from the first embodiment. Therefore, the same components are denoted by the same reference numerals and redundant description is omitted. Hereinafter, a control method of the printing device 11 according to the present embodiment will be described.

[0061] As shown in FIG. 8A, the intermediate roller 33a and the upstream conveyance drive roller 35a are rotated in the forward rotation direction W1, and the medium M is conveyed in the downstream direction D1 by the first conveyance roller pair 33 and the second conveyance roller pair 35. The control unit 58 stops the first conveyance roller pair 33 and the second conveyance roller pair 35 when the leading end Ma of the medium M has passed through the second nip portion Np2 by a predetermined passing amount. Note that the predetermined passing amount is appropriately set according to the rigidity of the medium M, the distance between the second nip portion Np2 and the third nip portion Np3, and the like.

[0062] Next, as shown in FIG. 8B, the control unit 58 rotates the upstream conveyance drive roller 35a in the reverse rotation direction W2 with the nip of the first nip portion Np1 released, and conveys the medium M so that the leading end Ma of the medium M is positioned upstream of the second nip portion Np2. In releasing the nip of the first nip portion Np1 in this embodiment, the energization of the coil of the electromagnetic clutch mechanism 333 is stopped. As a result, the power from the second drive device 334 to the intermediate roller 33a is cut off, and the intermediate roller 33a does not rotate drivenly and becomes in a state where it can rotate freely. Then, the control unit 58 discharges the leading end Ma of the medium M upstream from the second nip portion Np2, thereby forming a bend in the medium M between the first nip portion Np1 and the third nip portion Np3 and causing the leading end Ma of the medium M to follow the second nip portion Np2.

[0063] For example, when the leading end Ma of the medium M is inclined with respect to the width direction X and the leading end Ma on the -X direction side at the leading end Ma of the medium M is advanced and conveyed downstream, first, the portion on the -X direction side at the leading end Ma passes through the second nip portion Np2. In this state, when the second conveying roller pair 35 further conveys the medium M downstream, the portion on the +X direction side at the leading end Ma passes through the second nip portion Np2. That is, even when the medium M is inclined, the passing amount is set so that both the portion on the -X direction side and the portion on the +X direction side at the leading end Ma pass through the second nip portion Np2.

[0064] In this state, the control unit 58 rotates the second conveying roller pair 35 in the reverse rotation direction W2 in which the medium M is conveyed upstream with the nip of the first nip portion Np1 of the first conveying roller pair 33 released. First, the portion on the +X direction side at the leading end Ma passes through the second nip portion Np2, and when the second conveying roller pair 35 further conveys the medium M upstream, the portion on the -X direction side at the leading end Ma passes through the second nip portion Np2. As a result, both the portion on the -X direction side and the portion on the +X direction side at the leading end Ma are discharged upstream from the second nip portion Np2. That is, the entire leading end Ma of the medium M is discharged upstream from the second nip portion Np2.

[0065] Since the first nip portion Np1 is released, when the entire leading end Ma of the medium M is discharged upstream from the second nip portion Np2, a bend is formed in the medium M between the first nip portion Np1 and the third nip portion Np3. That is, by bending the medium M between the first nip portion Np1 and the third nip portion Np3, the medium M assumes a state in which the leading end Ma of the medium M follows the second nip portion Np2. Further, the bend of the medium M spreads upstream via the third nip portion Np3 and is gradually released. Then, with the leading end Ma of the medium M following the second nip portion Np2, the bend of the medium M is released between the first nip portion Np1 and the second nip portion Np2.

[0066] Next, the control unit 58 rotates the intermediate roller 33a and the upstream conveyance drive roller 35a in the forward rotation direction W1, and conveys the medium M in the downstream direction D1 by the first conveyance roller pair 33 and the second conveyance roller pair 35. With the leading end Ma of the medium M following the second nip portion Np2 and the bend between the first nip portion Np1 and the second nip portion Np2 being released, the medium M is conveyed downstream. Since the leading end Ma of the medium M follows the second nip portion Np2, when the second conveyance roller pair 35 rotates in the forward rotation direction W1, the leading end Ma of the medium M is nipped by the second nip portion Np2 in a state where the skew of the leading end Ma of the medium M is corrected. By conveying the medium M in the downstream direction D1 in this state, the medium M in a state where the skew is corrected can be conveyed to the printing unit 20.

[0067] As described above, according to the present embodiment, similar to the first embodiment, the skew of the medium M can be easily corrected.

[0068] 3. Third Embodiment Next, the third embodiment will be described. In the first embodiment, the leading end Ma of the medium M was abutted against the second nip portion Np2 of the stopped second conveyance roller pair 35, and with the leading end Ma of the medium M abutted against the second nip portion Np2, the intermediate roller 33a was rotated in the forward rotation direction W1 to further convey the medium M in the downstream direction D1, causing the leading end Ma of the medium M to follow the second nip portion Np2. In contrast, in the present embodiment, when the tip Ma of the medium M has passed through the second nip portion Np2 by a predetermined passing amount, with the first conveying roller pair 33 stopped, the upstream conveying drive roller 35a is rotated in the reverse rotation direction W2, and the medium M is conveyed so that the tip Ma of the medium M is positioned upstream of the second nip portion Np2, whereby the tip Ma of the medium M is made to follow the second nip portion Np2. Even in this case, the same effects as described above can be obtained.

[0069] 4. Fourth Embodiment Next, the fourth embodiment will be described. In the first embodiment, the electromagnetic clutch mechanism 333 is controlled to cut off the power from the second drive device 334 to the intermediate roller 33a to release the first nip portion Np1, but the present invention is not limited to this configuration. For example, as shown in FIG. 9, in the skew correction mechanism 190A of the printing apparatus 11A of the present embodiment, the driven roller 34a is configured to be separable from the intermediate roller 33a. In this case, a cam mechanism is provided on the rotation shaft of the driven roller 34a, and the control unit 58 drives and controls the cam mechanism to shift the driven roller 34a to a separated state or a contact state (nip state) with respect to the intermediate roller 33a. Even in this case, the same effects as described above can be obtained.

[0070] 5. Fifth Embodiment Next, the fifth embodiment will be described. In the printing apparatus 11 of the first embodiment, the configuration including the imaging device 90 as a device has been described, but the present invention is not limited to this. The device may be used for purposes other than conveying the medium M. For example, the device may be a cutting device. The cutting device includes a cutter and is capable of cutting the medium M. Further, the cutting device includes a pressing portion for pressing the medium M. The pressing portion is composed of, for example, a roller, a flat plate, or the like. By sandwiching the medium M from both sides with the pressing portion, the third nip portion Np3 can be formed. Even in this case, the same effects as described above can be obtained.

Description of Reference Numerals

[0071] 11, 11A... printing device, 20... printing unit, 21... carriage, 22... head, 27... cutting unit, 30... conveyance path, 30a... first path, 30b... curved path, 30c... second path, 30d... third path, 30e... reverse path, 31... conveyance unit, 32... supply roller pair, 33... first conveyance roller pair, 33a... intermediate roller, 34a... driven roller, 35... second conveyance roller pair, 35a... upstream conveyance drive roller, 35b... upstream conveyance driven roller, 36... downstream first conveyance roller pair, 37... downstream second conveyance roller pair, 38... downstream third conveyance roller pair, 58... control unit, 90... imaging device, 190, 190A... skew correction mechanism, 200... storage conveyance body, 333... electromagnetic clutch mechanism, 334... second drive device, 335... first drive device, 581... CPU, 582... memory, 583... control circuit, 584... I / F, 900... CIS module, 910... contact glass, 950... pressing unit, 951... pressing plate, 953... fixing member, D1... downstream direction, D2... upstream direction, P1... branch point, P2... confluence point, W1... forward rotation direction, W2... reverse rotation direction, Np1... first nip portion, Np2... second nip portion, Np3... third nip portion, M... medium.

Claims

1. A first pair of conveying rollers capable of conveying the medium while nipping the medium at a first nip portion, A second pair of conveying rollers disposed downstream of the first pair of conveying rollers and capable of conveying the medium while nipping the medium at a second nip portion, A device disposed between the first pair of conveying rollers and the second pair of conveying rollers in the conveying path of the medium and capable of nipping the medium at a third nip portion, and The nip force of the third nip portion is weaker than that of the first nip portion, A printing apparatus that causes the leading end of the medium to follow the second nip portion while the medium is nipped at the first nip portion, and then releases the nip of the first nip portion.

2. A first pair of conveying rollers capable of conveying the medium while nipping the medium at a first nip portion, A second pair of conveying rollers disposed downstream of the first pair of conveying rollers and capable of conveying the medium while nipping the medium at a second nip portion, A device disposed between the first pair of conveying rollers and the second pair of conveying rollers in the conveying path of the medium and capable of nipping the medium at a third nip portion, and The nip force of the third nip portion is weaker than that of the first nip portion, Convey the medium downstream with the leading end of the medium nipped at the second nip portion, Then, while releasing the nip of the first nip portion, convey the medium so that the leading end of the medium is located upstream of the second nip portion. A printing apparatus.

3. The printing apparatus according to claim 1 or claim 2, The device is used for purposes other than conveying the medium. A printing apparatus.

4. The printing apparatus according to claim 3, The device is an imaging device capable of reading information on the medium, The third nip portion is constituted by a pressing portion that presses the medium of the imaging device. A printing apparatus.

5. The printing apparatus according to claim 3, The device is a cutting device capable of cutting the medium, The third nip portion is constituted by a pressing portion that presses the medium of the cutting device. A printing apparatus.

6. The printing apparatus according to any one of claims 1 to 5, The release of the nip of the first nip portion is performed by making the rollers constituting the first pair of conveying rollers rotate freely. A printing apparatus.

7. A control method for a printing apparatus, comprising: a first pair of conveyance rollers capable of conveying a medium while nipping the medium at a first nip portion; a second pair of conveyance rollers disposed downstream of the first pair of conveyance rollers and capable of conveying the medium while nipping the medium at a second nip portion; and a device disposed between the first pair of conveyance rollers and the second pair of conveyance rollers in the conveyance path of the medium and capable of nipping the medium at a third nip portion, wherein the third nip portion is configured to have a weaker nip force than the first nip portion. A control method for a printing apparatus, comprising: causing the leading end of the medium to follow the second nip portion while the medium is nipped at the first nip portion, and then releasing the nip of the first nip portion. **Claim 8** A control method for a printing apparatus, comprising: a first pair of conveyance rollers capable of conveying a medium while nipping the medium at a first nip portion; a second pair of conveyance rollers disposed downstream of the first pair of conveyance rollers and capable of conveying the medium while nipping the medium at a second nip portion; and a device disposed between the first pair of conveyance rollers and the second pair of conveyance rollers in the conveyance path of the medium and capable of nipping the medium at a third nip portion, wherein the third nip portion is configured to have a weaker nip force than the first nip portion. A control method for a printing apparatus, comprising: conveying the medium downstream while the leading end of the medium is nipped at the second nip portion, and then conveying the medium such that the leading end of the medium is located upstream of the second nip portion while the nip of the first nip portion is released.

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