JP2014043025A - Recording apparatus, conveyance apparatus, and control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct skew at relatively low cost without preventing conveyance.SOLUTION: A recording apparatus that draws, from a roll body around which a recording medium is wound, the recording medium, and records an image on the recording medium includes recording means for recording the image on the recording medium, a conveyance roller for conveying the recording medium, first driving means for rotating the conveyance roller, second driving means for generating a braking force for the roll body, and control means for controlling the second driving means. The control means controls the second driving means so that tension and relaxation alternately occur in the recording medium between the conveyance roller and the roll body while the conveyance roller is conveying the recording medium.

Description

  The present invention relates to a sheet conveying technique.

  As one of recording media used in a recording apparatus, a roll body in which a sheet is wound is known as represented by roll paper. If the sheet is skewed, print quality may be adversely affected. For example, a part of the image may protrude from the sheet. Therefore, a technique for correcting the skew of the sheet has been proposed.

  For example, Japanese Patent Application Laid-Open No. H10-228667 proposes a torque limiter that provides a rotational load on a rotating shaft of roll paper to generate back tension on the fed paper. By generating tension on the paper by the back tension, the paper slides on the transport roller and the skew is corrected.

JP 2006-315777 A

  To increase the ability to correct skew using back tension as in Patent Document 1, the larger the back tension, the better. However, in order to increase the back tension, using a high-output drive source that applies a rotational load to the roll paper causes an increase in cost. Further, if the back tension becomes larger than the conveying force of the conveying roller, the conveying becomes impossible.

  An object of the present invention is to correct skewing relatively inexpensively without interfering with conveyance.

  According to the present invention, there is provided a recording apparatus that pulls out the recording medium from a roll body around which the recording medium is wound, and records an image on the recording medium, the recording unit that records an image on the recording medium, and the recording A transport roller that transports the medium, a first drive unit that rotates the transport roller, a second drive unit that generates a braking force on the roll body, and a control unit that controls the second drive unit. And the control means includes the second driving means so that tension and relaxation occur alternately in the recording medium between the conveying roller and the roll body during conveyance of the recording medium by the conveying roller. There is provided a recording apparatus characterized by controlling.

  According to the present invention, skew can be corrected relatively inexpensively without interfering with conveyance.

1 is a schematic diagram of a recording apparatus according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of the structure of the recording apparatus in FIG. 1. Explanatory drawing of the attachment structure of roll paper. Explanatory drawing of the drive mechanism regarding a conveyance roller. Explanatory drawing of the drive mechanism regarding roll paper. FIG. 2 is a block diagram of a control unit of the recording apparatus in FIG. 1. 10 is a flowchart illustrating a processing example when roll paper is exchanged. Explanatory drawing of tension etc. (A)-(c) is explanatory drawing of the control regarding skew feeding correction. Explanatory drawing of another example of the drive mechanism regarding roll paper. FIG. 3 is a block diagram of a roll paper conveyance control system.

<First Embodiment>
FIG. 1 is a schematic diagram of a recording apparatus 1 according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the structure of the recording apparatus 1. In the present embodiment, a case where the present invention is applied to an ink jet recording apparatus will be described, but the present invention can also be applied to other types of recording apparatuses.

  In “recording”, not only when significant information such as characters and figures is formed, but also regardless of significance, images, patterns, patterns, etc. are widely formed on the recording medium, or the medium is processed. It does not matter whether or not it is manifested so that humans can perceive it visually. In this embodiment, a sheet-like paper is assumed as the “recording medium”, but a cloth, a plastic film, or the like may be used.

<Configuration of recording apparatus>
The recording apparatus 1 pulls out the recording paper from a roll body (hereinafter referred to as roll paper) R around which the recording paper is wound, and records an image on the recording paper. FIG. 3 is an explanatory diagram of a roll paper R mounting structure.

  The spool shaft 32 penetrates the paper tube S at the winding center of the roll paper R. A reference-side roll paper holder 30 is fixed on the spool shaft 32 so as not to rotate, and the reference-side loading portion 31 bites into the inner wall of the paper tube S by the elastic force in the radial direction. Further, the non-reference-side roll paper holder 34 is passed through the spool shaft 32 from the opposite side of the reference-side roll paper holder 30 so as to sandwich the roll paper R, and set on the paper tube S. The non-reference-side roll paper holder 34 also has a non-reference-side loading portion 35 that is fixedly held to the paper tube S with an elastic force in the radial direction.

  Both ends of the spool shaft 32 are rotatably supported by the recording apparatus 1, whereby the roll paper R is also rotatably held. In the following description, the end of the recording paper fed out from the roll paper R is referred to as a leading end Rp, one side is referred to as a reference side end Rh, and the opposite end is referred to as an end Rb.

  1 and 2, the recording apparatus 1 includes an image recording unit 3 that records an image on a recording sheet on the downstream side of the roll paper R. The recording sheet is sent from the sheet feeding port 2 to the image recording unit 3. The conveyance direction of the recording paper is referred to as the sub-scanning direction, and the direction orthogonal to this is referred to as the main scanning direction.

  The image recording unit 3 includes a recording head 11, a carrier 12 on which the recording head 11 is mounted, and a platen 19 provided to face the recording head 11. The recording head 11 has a plurality of nozzle rows (not shown) in the sub-scanning direction of the surface facing the print surface, and ejects ink of different colors for each nozzle row. An image can be recorded on a recording sheet by ejecting ink. Each color nozzle is supplied with an ink of each color from an ink tank 14 via each supply tube 13. The ink tank 14 may be mounted on the carrier 12.

  The carrier 12 is slidably supported along a guide shaft 16 extending in the main scanning direction. Both ends of the guide shaft 16 are supported by the frame 15 of the apparatus body 1. The carrier 12 can be reciprocated in the main scanning direction by a drive mechanism (not shown). The position of the recording head 11 is detected by a sensor (not shown). Examples of such a sensor include an encoder scale extending in the main scanning direction and an encoder sensor mounted on the carrier 12 and reading the encoder scale.

  An end detection sensor 42 is mounted on the carrier 12. The edge detection sensor 42 is an optical sensor, for example, and is used to detect the edge of the recording paper. A sheet detection sensor 41 is provided in the middle of the transport path upstream of the recording head 11. The paper detection sensor 41 is an optical sensor, for example, and is used to detect passage of the leading edge Rp of the recording paper.

  A conveyance roller 9 and a pinch roller 10 extending in the main scanning direction are provided in the middle of the conveyance path upstream of the recording head 11. The conveyance roller 9 is a driving roller, and the pinch roller 10 is a driven roller that rotates with the conveyance roller. The recording sheet is conveyed in the sub-scanning direction so as to be sandwiched between the conveying roller 9 and the pinch roller 10.

  The transport roller 9 is rotated by the first drive mechanism 4 using the motor 8 as a drive source. FIG. 4 is an explanatory diagram of the drive mechanism 4. A gear 8 a is provided on the output shaft of the motor 8, and a gear 9 a that meshes with the gear 8 a is provided on the transport roller 9. Thus, the conveyance roller 9 can be rotated by the rotation of the motor 8. In the present embodiment, a gear mechanism is employed as a mechanism for transmitting the driving force of the motor 8, but other transmission mechanisms such as a belt transmission mechanism may be used.

  In the present embodiment, a detection unit that detects the rotation amount of the transport roller 9 is provided. In the case of this embodiment, the detection unit is a rotary encoder including a slit disk 81 and an optical sensor 82, but may be other types of sensors. The optical sensor 82 is a transmissive optical sensor including a light receiving element and a light emitting element facing each other, and is arranged to detect the presence or absence of a slit in the slit disk 81.

  Returning to FIGS. 1 and 2, in the recording apparatus 1 having such a configuration, the recording head 11 moves (scans) on the recording paper in the main scanning direction during recording. The recording head 11 ejects ink droplets during the movement. When an image for one line is recorded, the conveyance roller 9 is rotated to convey the recording paper by a predetermined pitch. Then, image recording of the next line is performed. By repeating this operation, an image is recorded on the entire page. Of the recording paper, the recorded portion is conveyed onto the paper discharge tray 22. When the image recording is completed, the recording sheet is conveyed to a predetermined cutting position by the conveying roller 9 and is cut by the cutter 21.

<Roll paper drive mechanism>
The recording apparatus 1 of the present embodiment includes a second drive mechanism that generates a braking force for the roll paper R. FIG. 5 is an explanatory diagram thereof. The drive mechanism 5 includes a motor 40 that is a drive source. A gear 40 a is provided on the output shaft of the motor 40, and a gear 27 is provided on the sprocket 32. The intermediate shaft 37 is provided with a gear 38 and a gear 36, and the gear 38 meshes with the gear 40 a and the gear 36 meshes with the gear 27, respectively.

  Thus, the roll paper R can be rotated by the rotation of the motor 40. A braking force can be applied to the roll paper R depending on the rotation direction of the motor 40. In the case of the present embodiment, the roll paper R can be rotated in the direction in which the recording paper is sent out by the rotation direction of the motor 40. In the present embodiment, a gear mechanism is employed as a mechanism for transmitting the driving force of the motor 40, but other transmission mechanisms such as a belt transmission mechanism may be used.

  In the present embodiment, a detection unit that detects the rotation amount of the roll paper R is provided. In the case of the present embodiment, the detection unit is a rotary encoder including the slit disk 39 and the optical sensor 50, but may be other types of sensors. The optical sensor 50 is a transmissive optical sensor including a light receiving element and a light emitting element facing each other, and is arranged to detect the presence or absence of a slit in the slit disk 39. In the case of this embodiment, the slit disk 39 is fixed to the intermediate shaft 37. Therefore, the rotation amount of the roll paper R is obtained by correcting the detection result of the optical sensor 50 with the gear ratio between the gear 36 and the gear 27.

<Control unit>
FIG. 6 is a block diagram of the control unit 100 of the recording apparatus 1. The control unit 100 includes a processing unit 101 such as a CPU, an interface unit 102 that exchanges data with an external device, and a storage unit 10 such as a ROM or a RAM. The processing unit 101 reads and executes a program stored in the storage unit 103.

  The arithmetic processing performed by the processing unit 101 includes, for example, image processing, communication processing with the host computer 200 via the interface unit 102, and reception processing of information input by the user via the operation unit 105. The operation unit 105 is, for example, an operation panel provided in the recording apparatus 1, and the user can input information such as the type of recording paper.

  The arithmetic processing performed by the processing unit 101 also includes, for example, ejection control of the recording head 11 and drive control of various motors 106 performed based on detection results of the various sensors 104. The various sensors 34 include a sensor for detecting the position of the recording head 11, a paper detection sensor 41, an edge detection sensor 42, optical sensors 50 and 82, and the like. The various motors 106 include a motor that is a drive source of the drive mechanism of the carrier 12, motors 8 and 40, and the like.

  The storage unit 103 stores, for example, a control program for controlling the recording apparatus 1 and data necessary for executing the control program. Further, for example, recording data transmitted from the host computer 200 may be stored.

  FIG. 11 is a block diagram of a roll paper R conveyance control system. The conveyance control unit 110 is realized by the control unit 100 described above, for example. The conveyance control unit 110 gives a command to both the LF motor control unit 111 and the paper feed motor control unit 112 in order to realize the correlation drive between the motor 8 and the motor 40. The LF motor control unit 111 and the paper feed motor control unit 112 are, for example, motor control circuits including a motor drive circuit and the like. Then, the operation state is acquired from the above-described optical sensor 82 that detects the rotation amount of the transport roller 9 and the above-described optical sensor 40 that detects the rotation amount of the roll paper R, and each of the motors 8 is based on the acquired information. And control the operation of the motor 40.

<Example of processing when replacing roll paper>
Next, as an example of processing executed by the processing unit 101, processing when the user replaces the roll paper R will be described with reference to FIG. In this embodiment, when the roll paper R is replaced, the skew correction of the recording paper is performed. The forward rotation direction of the transport roller 9 and the roll paper R refers to the rotation in the direction of sending the recording paper from the upstream side to the downstream side, and the opposite direction to the reverse rotation direction (returning the recording paper from the downstream side to the upstream side). Direction).

  First, the user sets a new roll paper R or a roll paper R used halfway in the recording apparatus 1 and inserts the leading end Rp of the recording paper into the transport port 2. Further, the user guides the leading edge Rp of the recording paper to the downstream side of the conveyance path by turning the roll paper R by hand.

  The processing unit 101 determines whether the leading edge Rp of the recording paper is detected based on the detection result of the paper detection sensor 41 in S1. If applicable, the process proceeds to S2. In S2, the rotation of the conveying roller 9 is started and the recording paper is conveyed. The recording paper is conveyed until at least the end detection sensor 42 detects the recording paper. The roll paper R is accompanied by the conveyance of the recording paper by the conveyance roller 9. When the recording paper transport is decelerated or stopped, the roll paper R tries to continue its rotational movement by its inertia. If it is left as it is, the recording paper may be loosened in the conveyance path, and the recording paper may be scratched or broken. Therefore, it is preferable to apply a braking force to the roll paper R by the drive mechanism 5.

  In S3, the radius of the roll paper R is calculated. The calculation result is used for estimating the inertia of the roll paper R. The radius of the roll paper R can be calculated based on the detection results of the optical sensors 50 and 82. That is, the rotation amount of the conveyance roller 9 and the roll paper R at the time of conveyance of the recording paper in S2 is calculated, and since the radius of the conveyance roller 9 is known, the radius of the roll paper R can be derived.

  In S4, a user's paper type input to the operation unit 105 is received and set. It is possible to estimate the ink discharge control setting and the inertia of the roll paper R depending on the paper type. The estimation of the inertia of the roll paper R uses the calculation result of S3. That is, the inertia of the roll paper R can be calculated from the radius of the roll paper R, the radius of the paper tube S, the unit mass of the recording paper, and the width. Information on the radius of the paper tube S, the unit mass of the recording paper, and the width can be stored in advance in the storage unit 103 for each type of recording paper, and can be specified according to the user's paper selection.

  In S5, the edge of the recording sheet is detected. Here, the carrier 12 is moved so as to cross the recording sheet, and the position information of the reference side end Rh and end Rb is stored in the storage unit 103 as Rh1 and Rb1 by the end detection sensor 42, respectively. Further, the sheet width is calculated from these differences and stored in the storage unit 103.

  In S6, the conveying roller 9 is rotated to convey the recording sheet by a predetermined amount L (conveying process). While the recording paper is being conveyed by the conveyance roller 9 (during the conveyance process), skew correction control is performed. Details will be described later.

  In S7, the skew amount of the recording paper is detected. Here, the carrier 12 is moved so as to cross the recording sheet, and the position information of the reference side end Rh is stored in the storage unit 103 by the end detection sensor 42 as Rh2. Then, the skew amount of the recording paper is calculated from the predetermined amount L of S6 by (Rh1-Rh2) / L. If the skew amount is not within the predetermined threshold, a process of requesting the user to reset is performed.

  In S8, the recording sheet is conveyed to the standby position. Specifically, the conveyance roller 9 is rotated in the reverse direction, and the recording sheet is returned until the leading end Rp of the recording sheet is positioned at a predetermined position on the upstream side. This predetermined position is, for example, where the tip Rp is located at a position of 5 mm downstream from the transport roller 9. Thus, one unit of processing is completed. Thereafter, an image recording operation on the recording sheet can be performed.

<Skewing correction control>
Next, the skew correction control executed in S6 will be described. In this embodiment, the recording paper is forward-fed in a state where the back tension is generated on the recording paper, whereby the recording paper is tensioned and the recording paper is slid on the conveying roller 9. As a result, the skew of the recording paper is corrected by making the orientation of the recording paper straight. At that time, by using the inertia of the roll paper R, a high tension is instantaneously generated and the correction effect is improved.

  FIG. 8 is an explanatory diagram of the tension and the like of the recording paper when the recording paper is conveyed, and is a relationship diagram of the torque generated by the conveying roller 9 and the roll paper R, the conveying speed, and the like.

  The driving torque of the motor 40 is Troll, the inertia of the roll paper R is Froll, and the tension (load force) applied to the recording paper between the transport roller 9 and the roll paper R is Tpap. Further, the conveying speed (circumferential speed) of the conveying roller 9 is set to Vlf, and the conveying speed (circumferential speed) of the roll paper R is set to Vroll.

One of the back tensions generated on the recording paper is caused by the driving torque Troll by the motor 40, and the other is caused by the inertia Froll of the roll paper R. The relationship between the tension troll generated in the recording paper by the driving torque Troll (back tension) of the motor 40, the gear ratio β from the motor 40 to the roll gear 27, and the radius r of the roll paper R is as follows:
β ・ Troll ＝ r ・ troll
It is represented by As can be seen from this equation, the tension troll can be adjusted by changing the driving torque Troll of the motor 40.

On the other hand, the relationship between the tension froll acting on the recording paper by the inertia Froll of the roll paper R, the rotation angle θ of the roll paper R, and the radius r of the roll paper R is as follows:
Froll · dθ ² / dt ² = r · froll
It is represented by

The inertia Froll of the roll paper R is calculated from the mass A of the roll paper R, the radius r, and the radius R of the paper tube S.
Froll = 1/2 ・ A ・ (r ² + R ² )
It is represented by The mass A is calculated from the width l of the roll paper R and the unit mass m.
A = (r ² -R ² ) ・ π ・ l ・ m
It is represented by

The rotation angle θ, the radius r of the roll paper R, and the conveyance acceleration α of the roll paper R are:
r · dθ ² / dt ² = α
It is represented by

Therefore, the tension froll acting on the recording paper by the inertia Froll of the roll paper R is
froll = 1/2 ・ π ・ m ・ l ・ α ・ {r ^2- (R ² / r) ² }
It is represented by

The tension Tpap applied to the recording paper between the transport roller 9 and the roll paper R is the sum of the tension troll by the driving torque Troll and the tension froll by the inertia Froll.
Tpap = troll + froll = β ・ Troll / r + 1/2 ・ π ・ m ・ l ・ α ・ {r ^2- (R ² / r) ² } Equation 1
It is represented by

  From Equation 1, it can be seen that the tension froll is obtained only when the conveyance acceleration α is present, that is, when the recording sheet is accelerating. In this embodiment, tension froll due to inertia is intentionally generated and used for skew correction. FIGS. 9A to 9C are explanatory diagrams thereof.

  FIG. 9A shows the recording sheet conveyance speed Vlf on the conveyance roller 9 and the recording sheet conveyance speed Vroll on the roll sheet R over time. FIG. 9B shows a driving state of the motor 40 on the same time axis as FIG. 9A. That is, the control content of the motor 40 for skew correction is shown. In the figure, “ON” generates a driving force for rotating the roll paper R in the reverse rotation direction, that is, a braking force is applied to the rotation of the roll paper R in the normal rotation direction. “OFF” indicates a drive stop state. FIG. 9C shows a tension troll and a tension froll on the same time axis as FIG. 9A.

  The time period 0 to t1 is an acceleration period of the transport roller 9 and the motor 8 rotates the transport roller 9 in the normal rotation direction. On the other hand, the motor 40 is also driven with a predetermined drive torque Troll, and both the drive torque Troll and the roll paper inertia Froll are generated.

  When the time t1 when the conveying speed Vlf of the conveying roller 9 reaches a predetermined speed is reached, thereafter, the rotational speed of the motor 8 is gradually reduced to gradually reduce the conveying speed Vlf.

  At the same time, the driving of the motor 40 is stopped. By setting the drive torque Troll to 0, the tension troll also becomes 0. This state is shown in the time interval t1 to t2. The reason why the transport speed Vroll in the roll paper R is relatively faster than the transport speed Vlf in the transport roller 9 is due to the inertia acting on the roll paper R. That is, the recording paper is slackened in the conveyance path during the section from time t1 to t2.

  In the period from time t2 to t3, the motor 40 is driven again. Thereby, the conveyance speed Vroll in the roll paper R is gradually decelerated and becomes relatively slower than the conveyance speed Vlf in the conveyance roller 9. In other words, the relaxation of the recording paper that occurs in the interval from time t1 to t2 gradually decreases in the interval from time t2 to t3, and then changes from relaxation to tension at time t3. At that time, a conveyance acceleration α occurs in the roll paper R. That is, as shown in Equation 1 and FIG. 9C, the tension froll due to the inertia of the roll paper R rises rapidly, and a high tension is instantaneously generated on the recording paper.

  Thereafter, during the period from time t3 to t4, the motor 40 continues to output the driving torque Troll. At time t4, the driving of the motor 40 is stopped again and the driving torque Troll is set to zero. Then, the transport speed Vroll on the roll paper R again exceeds the transport speed Vlf of the transport roller 9 and the recording paper is relaxed, so that the situation is the same as the above-described time interval t1 to t2.

  Thus, torque is intermittently generated from the motor 40, and this control cycle is repeated with the operation from time t1 to t4 as one control cycle. Tension and relaxation occur alternately in the recording paper, and when switching from relaxation to tension, the tension froll due to the inertia of the roll paper R rises rapidly and can act as a skew correction force. By using the inertia of the roll paper R, a large tension can be instantaneously generated on the recording paper, and the output of the motor 40 can be relatively low. That is, the apparatus can be configured at a relatively low cost. Further, since the recording sheet is intermittently relaxed, the conveyance of the recording sheet by the rotation of the conveying roller 9 is not hindered.

  In this embodiment, in order to generate the conveyance acceleration α, the motor 40 is repeatedly turned off and on while the conveyance speed of the conveyance roller 9 is reduced. However, the present invention is not limited to this. For example, the recording paper relaxation may be positively generated by the motor 40 by making the conveyance speed Vroll of the roll paper by the motor 40 faster than the conveyance speed Vlf of the conveyance roller 9. In this case, the conveyance speed Vlf of the conveyance roller 9 does not necessarily need to be reduced.

  Further, the tension Tpap acting as the skew correction force can be affected by the condition relating to the roll paper R, that is, the unit mass m, the width l, the radius r, the paper tube diameter R, and the like specific to the paper type, according to Equation 1. Recognize. Therefore, the control content of the motor 40 may be changed based on these. Accordingly, effective skew correction can be performed with an inexpensive configuration corresponding to the type of roll paper R.

  For example, if the unit mass m, the width l, and the radius r are small and the tension froll due to inertia is relatively small, the tension Tpap necessary and sufficient for skew correction may not be obtained. Therefore, when the inertia of the roll paper is calculated and the inertia is relatively small, a sufficient tension Tpap can be obtained by relatively increasing the driving torque Troll.

  As another method, the inertia of the roll paper may be calculated, and when the inertia is relatively small, the number of times that tension and relaxation are alternately generated on the recording paper may be relatively increased. In either case, the drive torque Troll and the number of alternate occurrences may be determined directly from at least one of the above-described conditions regarding the roll paper R without calculating the inertia.

  In this embodiment, in S3, the rotation amount of the transport roller 9 and the roll paper R when transporting the recording paper in S2 is calculated, and the radius of the roll paper R is derived. However, instead of this, the radius of the roll paper R may be derived from the rotation amount of the roll paper R when the recording paper is conveyed (predetermined amount L) in the skew correction of S6. In this case, the calculation result of the radius of the roll paper R can be stored in the storage unit 103 and used in the next skew correction in S6.

Second Embodiment
The drive mechanism of the roll paper R is not limited to the drive mechanism 5 described above. For example, a motor may not be used as a drive source.

  FIG. 10 shows another example of the drive mechanism for the roll paper R. The difference from the drive mechanism 5 of the first embodiment is that a torque limiter 51 is provided instead of the motor 40 as a load generation source for applying a back tension to the roll paper R.

  The torque limiter 51 has an inner ring fastened to the intermediate shaft 37 and an outer ring fastened to the gear 38. When the intermediate shaft 37 rotates with the gear 38 stopped rotating, a predetermined back tension is applied. Yes.

  The gear 38 is connected to the gear portion of the electromagnetic clutch 52, and when the electromagnetic clutch 52 is excited (ON), the gear 38 is in a non-rotating state, and a braking force can be applied to the roll paper R. Further, when the excitation is released (OFF), no rotational load is generated on the roll paper R.

  Even in such a configuration, the same effect as in the first embodiment can be obtained. For example, in FIGS. 9A to 9C, the electromagnetic clutch is turned on at time t0 to t1 or t3 to t4, and the electromagnetic clutch is turned off at time t1 to t3.

  In this embodiment, since the motor 40 is not driven in the reverse direction, the transport speed Vroll in the roll paper R does not become the reverse direction (-) as shown in FIG. However, if the transport speed Vroll of the roll paper R is slower than the transport speed Vlf of the transport roller 9, the tension froll due to the inertia of the roll paper R can be generated. The tension froll is the largest when Vroll is 0 (that is, the roll paper R is stopped rotating). As a result, the same effects as in the first embodiment can be obtained in this embodiment.

<Other embodiments>
In the above embodiment, the recording apparatus is a target, but the field of application of the present invention is not limited to this, and the present invention can be applied to various conveying apparatuses that draw and convey a sheet from a roll body around which the sheet is wound.

Claims (6)

A recording apparatus that pulls out the recording medium from a roll body around which the recording medium is wound, and records an image on the recording medium,
Recording means for recording an image on the recording medium;
A transport roller for transporting the recording medium;
First driving means for rotating the transport roller;
Second driving means for generating a braking force on the roll body;
Control means for controlling the second drive means,
The control means includes
The second drive unit is controlled so that tension and relaxation occur alternately in the recording medium between the transport roller and the roll body during transport of the recording medium by the transport roller. Recording device. The second driving means generates a torque for rotating the roll body in a reverse rotation direction;
2. The recording apparatus according to claim 1, wherein the control unit intermittently generates the torque in the second driving unit during conveyance of the recording medium by the conveyance roller.   The recording apparatus according to claim 2, wherein the control unit changes the magnitude of the torque according to a condition related to the roll body.   The recording apparatus according to claim 1, wherein the control unit changes the number of times that tension and relaxation are alternately generated in the recording medium according to a condition relating to the roll body. A conveying device that pulls out and conveys the sheet from a roll body around which the sheet is wound,
A conveying roller for conveying the sheet;
First driving means for rotating the transport roller;
Second driving means for generating a braking force on the roll body;
Control means for controlling the second drive means,
The control means includes
The conveyance is characterized in that the second driving unit is controlled so that tension and relaxation are alternately generated between the conveyance roller and the roll body during conveyance of the sheet by the conveyance roller. apparatus. A method for controlling a conveying device that pulls out and conveys the sheet from a roll body around which the sheet is wound,
The transfer device
A conveying roller for conveying the sheet;
First driving means for rotating the transport roller;
Second driving means for generating a braking force on the roll body,
The control method is:
A conveying step of driving the first driving means and conveying the sheet by the conveying roller;
Controlling the second driving means so that tension and relaxation occur alternately in the sheet between the transport roller and the roll body during the transport process;
The control method characterized by including.

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