JP2004142418A - Roll-paper feeding mechanism for recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To convey roll paper with high accuracy by imposing a fixed load on a grip part for feeding a pay-out part of the roll paper to a recording part. <P>SOLUTION: Paired holder arms 28, which are urged in prescribed directions, are turnably supported on both the sides of a feed path for an image creating medium, and two tension rollers 32 and 34 are turnably supported on the paired holder arms 28. The pay-out part of the image creating medium is laid in a zigzag manner across the tension rollers 32 and 34, and tension is imparted to the image creating medium. When the holder arm 28 is oscillated up to a prescribed position, a delivery motor 24 is driven, and the image creating medium is sent out from a roll part 14a in prescribed quantities. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a roll paper supply mechanism mainly used for a large-sized recording apparatus such as an ink jet printer.
[0002]
[Prior art]
In a large-sized inkjet printer, when a large roll paper made of a material such as paper, synthetic resin, or plastic is conveyed to the recording unit, the weight of one roll paper is as much as 100 kg. Also, if the media is so large, the roll paper itself does not become a perfect circle, and when the roll paper is set in the apparatus, the roll paper diameter may be eccentric with respect to the axis. . In such a case, if the roll paper is pulled out from the roll, the roll will not rotate smoothly due to the eccentricity of the roll, and the load on the grip will change, causing slippage at the grip. Occurs, which adversely affects the accuracy of paper feeding.
[0003]
If the roll paper on the supply side is always slack and this slack is conveyed to the recording unit by the grip unit, the grip unit is affected by the eccentricity of the roll paper and the weight change due to the change in diameter. Although the feeding portion can be smoothly conveyed, there is a problem that the feeding portion is skewed unless the back tension is applied while the feeding portion is free. In order to solve this problem, a bar-shaped weight member is arranged in the supply path of the roll paper so as to be vertically movable, and the weight member is placed on the loosened portion of the roll paper, and the weight member is attached to the roll paper. A mechanism has been developed in which a tension is applied by weight and the roll paper is conveyed by a grip portion against the tension.
[0004]
In addition, a mechanism has been developed in which both ends of the weight member are linked to the output shaft of the torque motor, and the rotation torque of the torque motor applies tension to the rolled portion of the roll paper. These mechanisms have a configuration in which a slack portion curved in a U-shape is always formed in a rolled-out portion of a roll paper by a weight member, and when the bent portion is reduced, the roll portion of the roll paper is sequentially rotated by a motor in a feeding direction. Has become. A printer configured such that a fixed roller is fixed between one of a pair of swing arms and a rotating roller is attached to the other, and a sheet is pressed against these rollers so that the angle of the swing arm is always constant during sheet conveyance. Is also known (for example, see Patent Document 1).
[0005]
[Patent Document 1]
JP-A-11-246093 (page 5, FIG. 5, 6)
[0006]
[Problems to be solved by the invention]
The conventional mechanism that puts the weight rod on the curved part of the roll paper reeling part and applies tension to the reeling part uses a guide rail for synchronizing the left and right ends of the weight rod and moving the rod parallel to the left and right. There is a problem that the required structure becomes complicated. Further, in the conventional mechanism in which a fixed roller is provided on one of the swing arms, the fixed roller does not rotate, so that the paper cannot be transported smoothly. To solve this problem by making the fixed roller rotatable, a phenomenon occurs in which the two rollers of the swing arm are not parallel and are twisted. Further, there is a problem that the skew of the sheet cannot be sufficiently controlled only by pressing the rotating roller against the sheet and applying tension to the sheet.
An object of the present invention is to solve the above problems.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a method for rotatably supporting a roll portion of an image forming medium wound in a roll shape, and linking a rotation support portion of the roll portion to a delivery motor controlled by a controller. The drawing medium extracted from the roll portion is nipped by a grip portion composed of a driving roller and a pinch roller, and while the driving roller rotates, the drawing medium is sent in the X-axis direction, while the printing head is scanned by the recording head to scan the drawing medium. In a roll paper supply mechanism for a recording device, which performs printing and printing, rotates the roll portion in the sending direction by the sending motor, and sequentially supplies the drawing medium from the roll portion to the grip portion, a supply path of the drawing medium A pair of holder arms urged in a predetermined direction positioned on both sides of the recording medium are swingably supported on the body side of the recording apparatus. A tension roller is rotatably supported, and a tensioned portion of the drawing medium is provided between the grip portion and the roll portion by applying pressure to the tension roller by pressing a drawn portion of the drawing medium. The holder arm swings against the urging force in response to the change in the force to prevent an increase in the tension of the hollow portion, and when the holder arm swings to a predetermined position, the delivery motor is driven, and A fixed amount of drawing medium is sent out from the roll section, and the holder arm is returned to the original position by the urging force.
[0008]
Further, according to the present invention, two tension rollers are supported in parallel on the pair of holder arms at an appropriate interval, and the drawing medium is stretched over the two tension rollers so as to bend in a zigzag shape. It is.
[0009]
Further, according to the present invention, the two tension rollers include a first tension roller and a second tension roller, and an axial reinforcing member is disposed between each one of the pair of holder arms. One end of the pair of holder arms is fixed to both ends of the body so as to face each other in parallel, the first tension roller is rotatably fitted to the outside of the reinforcing body, and both ends of the reinforcing body are The second tension roller is rotatably mounted on the body of the recording apparatus so as to be rotatably mounted between the other of the holder arms and in parallel with the first tension roller, and the drawing medium is zigzag. The belt is wound around the two tension rollers so as to bend in a shape.
[0010]
Further, according to the present invention, a shaft-like reinforcing member is arranged on the pair of holder arms, and both ends of the reinforcing member are fixed to portions of the holder arm separated from a rotating portion.
[0011]
Further, according to the present invention, the drawing medium is drawn out from a roll portion, and after the drawing portion is sandwiched between the grip portions, the feed motor is rotated in the reverse direction before printing is performed to print the drawing portion by a predetermined amount. The loosened portion of the drawn-out portion of the drawing medium between the grip portion and the roll portion is removed, and the drawing medium is pressed against the tension roller to apply tension to the drawing medium.
[0012]
Further, according to the present invention, the holder arm is urged in a predetermined direction by its own weight, and the holder arm returns to its original position by its own weight when a predetermined amount of the image forming medium is sent out from the roll section by the sending motor. It was made.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.
In FIG. 1, reference numeral 2 denotes a recording device composed of a large-sized ink jet printer, and legs 6 are provided upright on a pair of footrests 4, respectively. Reference numeral 8a denotes a front paper guide, 8b denotes a rear paper guide, and 10 denotes a platen, each of which is made of a metal plate and is fixed to the machine body 12 supported by the leg body 6, respectively. A pair of bearing members 18 and 20 are disposed on the left and right rear sides of the lower portion of the leg 6 respectively. Reference numeral 14 denotes a roll paper made of paper, synthetic resin, plastic, or the like. The roll portion 14a is mounted on a roll paper supply scroller 16 as shown in FIG. Shafts 16 a projecting from the centers of both ends of the roll paper supply scroller 16 are mounted on a pair of bearing members 18, 20. The pair of bearing members 18 and 20 are rotatably supported by substrates of sending devices 22 and 22 disposed below the left and right legs 6 and 6, respectively.
[0014]
One of the pair of bearing members 18, 20 on the one delivery device 22 side of the left and right delivery devices 22, 22 is connected to the output shaft of the media delivery motor 24 via a power transmission mechanism. ing. The flange portion of the supply scroller 16 is rotatably abutted on a corresponding substrate of the sending devices 22, 22, and the axial movement of the supply scroller 16 is locked by the flange portion and the substrate. Brackets 26, 26 are fixedly mounted on the left and right sides of the body 12 at the same height and opposed to each other, and the brackets 26, 26 protrude toward the back of the recording apparatus 2. Reference numerals 28, 28 denote L-shaped plate-shaped holder arms, each of which has a shaft 30 protruding at an intermediate portion. The shaft body 30 of the holder arms 28, 28 is supported by the brackets 26, 26 so as to be rotatable about an axis parallel to the floor.
[0015]
A tension roller 32 is hung between the L-shaped ends of the pair of holder arms 28 and 28 so as to be rotatable and horizontally with respect to the floor surface. Between the other ends of the pair of holder arms 28, 28, a tension roller 34 is hung rotatably and horizontally with respect to the floor surface. A shaft-like reinforcing member 36 for preventing the holder arms 28, 28 from being twisted is disposed between intermediate portions of the pair of holder arms 28, 28 near the shaft body 30, and both ends of the holder arms 28, 28 correspond to holders. It is fixed to an intermediate portion between the arms 28, 28. One of the pair of brackets 26, 26 is provided with a flag detection sensor 38, as shown in FIG. A flag 40 is fixed to the shaft 30 so as to swing in conjunction with the swing of the holder arm 28, and a detection section of the sensor 38 is located on the swing path of the flag 40.
[0016]
Further, on the lower front side of the leg 6, both end shaft portions 40 a of the roll paper take-up scroller 40 are supported by a pair of bearing members 42, 44 rotatably arranged on the left and right sides of the leg 6. The pair of bearing members 42 and 44 are each rotatably supported by a substrate of a winding device provided on the leg body 6, and one of the bearing members 42 is an output of a roll paper winding motor 46 via a power transmission mechanism. The other bearing member 44 is connected via a power transmission mechanism to a slit disc of an encoder 48 that detects the rotational movement of the bearing member 44. Below the take-up scroller 40, there is disposed a light transmission type slack detection sensor 50 for detecting a slack of the imaged roll paper and comprising a transmitting unit and a receiving unit such as an infrared beam.
[0017]
Behind the rear paper guide 8b, a guide roller 52 extending in the direction perpendicular to the paper surface of FIG. 1, that is, in the Y-axis direction is disposed, and the guide roller 52 is rotatably supported by the machine body. Numeral 54 denotes a Y-axis rail, which is horizontally disposed above the paper guide 8b, and both ends of which are fixed to the body via brackets. A Y cursor 56 (carriage) is movably attached to the Y-axis rail 54, and the Y cursor 56 is provided on an airframe via an endless steel belt connected to a Y-axis drive motor. The shaft driving device 58 is linked.
[0018]
A slit is formed between the platen 10 and the rear paper guide 8b along the Y-axis direction, and a driving roller 60 is disposed in the slit. Both ends of the driving roller 60 are linked via a bracket to an X-axis driving device 62 disposed on the body. A large number of pinch roller arms are swingably mounted on the Y-axis rail 54 via a resilient mechanism (not shown), and the pinch roller 64 rotatably supported by the pinch roller arm includes the drive roller It is configured to be able to set one of a state separated from the surface of the surface 60 and a state elastically contacted with the surface horizontally.
[0019]
A head base is fixed to one side of the Y cursor 56, and four ink jet recording heads 66 provided for each color of ink, each having a large number of nozzles, are fixed to the head base.
Next, the operation of the present embodiment will be described.
To set the rolled portion of the roll paper 14 on the platen 10, the pinch roller 64 is raised, and the roll paper 14 is drawn out manually from the roll portion 14 a of the roll paper 14 set on the supply scroller 16. The portion is zigzagly wound around the inside of the tension roller 34 (ie, the left side in FIG. 1) and the outside of the tension roller 32 (ie, the right side in FIG. 1).
[0020]
The outer roll paper wound so that the drawing execution surface is on the outside is drawn out from the outside of the supply scroll 16 as shown in FIG. 1, and the inner roll paper is fed as shown by 14 'in FIG. It is drawn out from the inside of the scroller 16. The swing range of the holder arm 28 is restricted within a range of approximately 90 degrees, and the weight of the tension rollers 32, 34 and the like applied to the eccentric portion of the holder arm 28 causes the holder arm 28 to move clockwise about the shaft 30 in FIG. Being energized. In the no-load state, the holder arm 28 is locked at a downward swing limit position set clockwise.
[0021]
In the downward swing limit position of the holder arm 28, the tension roller 32 moves to the lower limit position indicated by reference numeral 32a in FIG. 2, and in this state, the protruding portion of the roll 14 hung on the tension rollers 34, 32 The zigzag shape is most bent, and the length between the roll portion 14a and the guide roller 52 is the longest. In FIG. 2, 32c indicates the upper limit position of the tension roller 32. Furthermore, the rolled-out portion of the roll paper 14 is guided to the winding scroller 40 via the guide roller 52 and the driving roller 60 and the pinch roller 64, the platen 10, and the paper guide 8a, and the leading end of the drawn-out portion is locked to the winding scroller 40. .
[0022]
Next, the pinch roller 64 is lowered, and the pinch roller 64 is brought into elastic contact with the drive roller 60 from above the drawn portion of the roll paper 14. Thereby, the roll paper 14 (drawing medium) is gripped by the drive roller 60 and the pinch roller 64, and the setting of the drawing medium is completed. In this state, the rolled portion of the roll paper 14 which is normally located between the guide roller 52 and the supply scroller 16 has slack, and no tension is generated in the drawn out portion. Therefore, before starting the printing operation with the roll paper set, the controller 68 performs the following initial operation. First, the delivery motor 24 is driven in the reverse direction, and the supply scroller 16 is reversely rotated in the paper winding direction, that is, clockwise in FIG. As a result, the rolled-out portion of the roll paper 14 is wound up by the supply scroller 16. In this process, tension is generated at the protruding portion of the roll paper 14, and a rotational force acts on the holder arm 28 in the counterclockwise direction in FIG. 1 via the tension rollers 34 and 32.
[0023]
Due to this rotational force, the holder arm 28 rotates counterclockwise in FIG. 1 against the urging force due to its own weight. When the tension roller 32 reaches the sending operation position 32b shown in FIG. 2, the sensor flag 40 moves to the detection unit of the sensor 38. Thus, the sensor 38 detects the sending operation position 32b of the tension roller 32. The controller 68 drives the delivery motor 24 in the roll paper delivery forward direction for a predetermined time based on the detection signal from the sensor 38. By the driving of the delivery motor 24, the supply scroller 16 rotates in the counterclockwise direction in FIG. 1, that is, the direction in which the roll paper 14 is delivered, and the roll paper 14 is protruded from the roll portion 14a by a predetermined amount. As a result, the pressure on the tension rollers 32 and 34 from the roll paper draw-out portion decreases, and the holder arm 28 rotates clockwise in FIG.
[0024]
Shortly before the tension roller 32 reaches the lower limit position 32a, the driving of the delivery motor 24 stops. In this state, the rolled portion is bent in a zigzag shape at a steep angle by the tension rollers 34 and 32. In this state, tension is applied to the drawn portion of the roll paper 14 by the eccentric moment in the clockwise direction in FIG. 1 due to the weight of the holder arm 28. Thereby, the slack of the roll paper 14 in the initial state at the time of setting the roll paper is removed, and the rolled paper 14 is in a state where tension is applied to the protruding portion. This tension is set so that the supply scroller 16 placed on the bearing members 18 and 20, ie, the roll portion 14a of the roll paper 14, does not rotate.
[0025]
When the printer shifts to the drawing operation, the rolled-out portion of the roll paper 14 is conveyed on the platen 10 in the X-axis direction by the intermittent rotation of the drive roller 60 in one direction. Further, the recording head 66 is driven based on the image information under the control of the controller 68, ejects ink, and reciprocates the Y cursor 56 along the Y-axis rail 54 to move the roll paper 54 along the Y-axis. By scanning the drawing portion, the image information developed in the memory of the controller 68 is visualized on the drawing execution surface of the roll paper 14. During drawing, when the roll paper 14 is sequentially pulled out onto the platen 10 by the grip portion including the drive roller 60 and the pinch roller 64, the tension rollers 32 and 34 are pressed by the rolled-out portion of the roll paper 14 and the holder arm 28 is pressed. 1 rotates counterclockwise around the shaft body 30 in FIG. 1 against the eccentric moment due to its own weight.
[0026]
In this state, the pulling / conveying force, that is, the load of the grip, on the roll paper feeding portion by the grip portion is kept constant. When the tension roller 32 reaches the sending operation position 32b, the controller 68 detects this by a signal from the sensor 38 and drives the sending motor 24 in the roll paper 14 sending direction for a certain time. As a result, the holder arm 28 rotates clockwise in FIG. 1 by its own weight, and the protruding portion of the roll paper 14 is bent deeply in a zigzag manner by the tension rollers 32 and 34. Shortly before the tension roller 32 reaches the lower limit position 32a, the driving of the delivery motor 24 is stopped, and this operation is repeated.
[0027]
During the drawing, when the slack of the printed sheet 14 discharged from the front of the platen 10 exceeds a certain amount, the slack detection sensor 50 detects the slack of the sheet 14. The controller 68 drives the take-up motor 46 to take up the printed portion of the sheet on the take-up scroller 40. In addition, a sensor mechanism for separately detecting the lower limit position 32a of the tension roller 32 is provided, and when the tension roller 32 reaches the lower limit position 32a, the driving of the delivery motor 24 in the roll paper delivery direction is stopped by a signal from the sensor. Various other design changes are possible when implementing the present invention. Further, in the present embodiment, since the paper 14 is wrapped around the two tension rollers 32 and 34 in a zigzag manner, the skew of the paper 14 can be effectively controlled, and the supply path of the paper 14 to the grid portion can be accurately determined. Can be set.
[0028]
Next, another embodiment of the present invention will be described with reference to FIGS.
Reference numerals 70 and 72 denote support plates, which are fixed to the bracket 26 on the machine body side, and support portions 70A and 72A facing each other in parallel are arranged on both sides of the supply path of the paper 14. Numeral 74 denotes a shaft-shaped reinforcing member longer than the width of the paper 14, and includes a cylinder 74A, cylindrical plugs 74B and 74C fixed to the inner diameter portions at both ends of the cylinder 74A, and a cylindrical plug 74B and 74C. It comprises support shafts 74D and 74E fixed at the center, and board bodies 74F and 74G fixed to the support shafts 74D and 74E, and these are integrally formed. In the reinforcing member 74, support shafts 74D and 74E are rotatably supported by support portions 70A and 72A of the support plates 70 and 72 via bearings 76 and 78 in a state parallel to the floor surface. I have. Holes formed in one of the pair of holder arms 80 and 82 are fitted into the boss portions of the board bodies 74F and 74G.
[0029]
In this state, one of the pair of holder arms 80 and 82 is fixed to both ends of the reinforcing body 74 by screws 88 via bearing retaining plates 84 and 86 so as to be parallel to each other. Slots 90, 92 of holder arms 80, 82 into which screws 88 are inserted are for adjusting the parallelism of holder arms 80, 82 with each other. A first tension roller 94 is loosely fitted on the outer peripheral surface of the reinforcing member 74, and both ends of the tension roller 94 are rotatably connected to the vicinity of both ends of the reinforcing member 74 via bearings 96 and 98. . On the open end side of the holder arms 80 and 82, a second tension roller 100 is provided at a predetermined distance from the first tension roller 94 so as to be parallel to the tension roller 94. Are located. The shafts 102 and 104 fixed to the second tension roller 100 project from the centers of both ends of the tension roller 100.
[0030]
The shafts 102 and 104 are rotatably supported on the open ends of the holder arms 80 and 82 via bearings. As described above, by fixing one side of each of the pair of holder arms 80 and 82 to both ends of the reinforcing member 74, even if a load is applied to the two tension rollers 94 and 100, the tension rollers 94 and 100 can be held between the tension rollers 94 and 100. The tension rollers 94 and 100 can be stably held in parallel without twisting. In the figure, 106 is a flag detection sensor attached to the support plate 72, 108 is a flag attached to the holder arm 82, and 110 and 112 are stoppers for restricting the swing range of the holder arm 80.
[0031]
In the above-described configuration, the sheet 14 drawn from the roll portion, that is, the image forming medium, is zigzagly wrapped around the tension rollers 94 and 100 as shown in FIG. During printing of the recording apparatus, when the image forming medium is pulled by the grip portion and the tension roller 100 is raised to the sending operation position indicated by the dotted line, the flag 108 is detected by the sensor 106, and the sending motor is driven to print the image from the roll portion. Medium 14 is supplied. Shortly before the tension roller 100 reaches the lower limit position, the driving of the delivery motor stops. This operation is the same as in the first embodiment, and a detailed description thereof will be omitted. In the above embodiment, the tension of the paper 14 can be changed by attaching a weight or the like to the holder arms 80 and 82. Similarly, the tension of the paper 14 can be changed by changing the length of the holder arms 80 and 82 or by allowing the position of the tension roller 100 with respect to the holder arm 82 to move inward. can do.
[0032]
【The invention's effect】
Since the present invention is configured as described above, the transport load for drawing out the image forming medium to the recording unit can be made constant with a simple configuration, and the image forming quality can be improved. Further, since the twist between the two rotary tension rollers can be prevented and the parallelism can be maintained, the supply of the drawing medium can be performed accurately.
[Brief description of the drawings]
FIG. 1 is an overall side view of a recording apparatus.
FIG. 2 is a side view of a main part of the present invention.
FIG. 3 is an external view explanatory view of the present invention.
FIG. 4 is an explanatory diagram showing a sending mechanism of the present invention.
FIG. 5 is an overall rear view of the recording apparatus.
FIG. 6 is a functional block diagram of the present invention.
FIG. 7 is a plan sectional view showing another embodiment of the roll paper supply mechanism for a recording apparatus according to the present invention.
FIG. 8 is a partial side view of the same.
[Explanation of symbols]
2 Recording device 4 Footrest 6 Leg 8a Paper guide 8b Paper guide 10 Platen 12 Body 14 Roll paper 16 Supply scroller 18 Bearing member 20 Bearing member 20 Paper guide 22 Sending device 24 Sending motor 26 Bracket 28 Holder arm 30 Shaft 32 Tension Roller 34 Tension roller 36 Reinforcement member 38 Flag detection sensor 40 Rewind scroller 42 Bearing member 44 Bearing member 46 Rewind motor 48 Encoder 50 Looseness detection sensor 52 Guide roller 54 Y-axis rail 56 Y cursor 58 Y-axis drive device 60 Drive roller 62 X-axis driving device 64 Pinch roller 66 Recording head 68 Controller 70 Support plate 74 Reinforcement 76 Bearing 78 Bearing 80 Holder arm 82 Holder arm 84 Bearing missing Because 86 Bearing retainer 88 Screw 90 slot 92 slot 94 first tension roller 96 Bearings 98 Bearings 100 second tension roller 102 shaft 104 shaft 106 flag detecting sensor 108 flags 110 the stopper 112 stopper

Claims (6)

A roll portion of the drawing medium wound in a roll shape is rotatably supported, and the rotation support portion of the roll portion is linked to a delivery motor controlled by a controller, and the drawing medium extracted from the roll portion is driven by a driving roller. And a pinch roller, the recording medium is fed in the X-axis direction by the rotation of a driving roller, while the recording head scans the image forming medium to perform printing on the image forming medium. In the roll paper supply mechanism for a recording device, the recording medium is supplied to the grip portion sequentially from the roll portion in the feeding direction. The biased holder arm is swingably supported on the body side of the recording apparatus, and two tension rollers are rotatably supported on the pair of holder arms, The drawn portion of the drawing medium is pressed against a tension roller to apply tension to the drawn portion, and the holder arm is moved in accordance with a change in the length of the drawn portion of the drawing medium between the grip portion and the roll portion. When the holder arm swings to a predetermined position by swinging against the urging force to prevent the tension of the drawing portion from increasing, the sending motor is driven, and a predetermined amount of the image forming medium is sent from the roll portion. Wherein the holder arm returns to the original position by an urging force. The two tension rollers are supported in parallel on the pair of holder arms at appropriate intervals, and the drawing medium is stretched over the two tension rollers so as to bend in a zigzag shape. Item 2. A roll paper supply mechanism for a recording apparatus according to Item 1. The two tension rollers include a first tension roller and a second tension roller, and an axial reinforcing member is disposed between each one of the pair of holder arms. Are fixed so as to face each other in parallel to each other, the first tension roller is rotatably fitted to the outside of the reinforcing member, and both ends of the reinforcing member are rotated to the body of the recording apparatus. The second tension roller is rotatably mounted between the other of the holder arms so as to be opposed to the first tension roller in parallel, and the drawing medium is bent in a zigzag manner. The roll paper supply mechanism for a recording apparatus according to claim 1, wherein the roll paper supply mechanism extends over the two tension rollers. 3. The recording apparatus according to claim 1, wherein a shaft-shaped reinforcing member is disposed on the pair of holder arms, and both ends of the reinforcing member are fixed to portions of the holder arm separated from a rotating portion. Roll paper supply mechanism. After the drawing medium is drawn out from the roll portion, and after the drawing portion is sandwiched by the grip portion, the printing motor is reversely rotated before printing and drawing, and the drawing portion is wound around the roll portion by a predetermined amount, and the grip is gripped. 4. A slack in a drawn-out portion of a drawing medium between a portion and a roll portion is removed, and the drawing medium is pressed against the tension roller to apply tension to the drawing medium. The roll paper supply mechanism for a recording apparatus according to claim 3. The holder arm is urged in a predetermined direction by its own weight, and the holder arm returns to the original position by its own weight when a predetermined amount of the image forming medium is sent from the roll unit by the sending motor. The roll paper supply mechanism for a recording apparatus according to claim 1, wherein:

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