JP2010201690A - Recording medium feeder and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a recording medium from being sagged, and to stably convey the recording medium, without generating a skew error, and to provide simple constitution of a long life. <P>SOLUTION: This recording medium feeder includes a pair of flange members 1 with a diameter smaller than the maximum diameter of a roll paper sheet 2, two front rollers 5 for holding freely rotatably the flange members, a pair of support roller sets comprising a rear roller 24, with one thereof movable along a longitudinal direction of the roll paper sheet 2, a paper sheet supply roller 6 for feeding out the recording medium from the roll paper sheet 2 to a printing part, a paper sheet supply motor 7 for driving the roll paper sheet 2, a rerolling roller 4 engaged with the front rollers 5 and for driving the flange members 1 along a rerolling direction of the recording medium for a prescribed time, a conveying guide 10 for imparting a tension onto a paper sheet with respect to the printing part, and a spring 11. The rerolling roller 4 includes a one-way clutch 27 for transmitting only a rerolling-directional driving force from the paper sheet supply motor 7, to be longer than the maximum separation distance between the both support roller sets, and the conveyance of the recording medium in a portion related to a printing operation is stopped during an operation of the printing part, to rotate alternately the paper sheet supply motor 7 normally and reversely. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a recording medium sending apparatus and an image forming apparatus, and more particularly to a recording medium sending apparatus that feeds sheet paper from roll paper used as a recording medium, and an image forming apparatus including the recording medium sending apparatus.

  In general, roll paper is often used as a recording medium in electrophotographic image forming apparatuses such as large copying machines, printers, and other printing apparatuses that handle large-size drawing originals such as A0 size and A1 size. This is for the convenience of handling the paper, which is a recording medium when performing image formation using a large-size recording medium, and is a recording in which the sheet paper is fed out from the roll paper and sent to the image forming unit. A media delivery device is used.

  In such an image forming apparatus, a plurality of roll papers having different paper qualities and paper sizes are mounted on the recording medium delivery device, paper is selected according to the size of the original, and paper is fed toward the recording unit. The selected paper is fed out from the roll paper and cut according to the length of the original by a cutter arranged upstream from the transfer position of the image carrier, and the image is transferred to the cut paper (sheet paper). Then, the image is fixed and image formation is completed. In actual operation, a forward / reverse drive mechanism is provided in the transport roller device for feeding the paper pulled out from the roll paper, and after cutting the paper with a cutter, the paper leading end on the roll paper side is set at the standby position (from each roll paper). In order to return to the position upstream of the paper merging portion, the transport roller device is reversely rotated using the forward / reverse driving means to perform the paper returning operation. Such control is performed in order to prevent a situation in which a multi-feed state occurs due to interference between the leading end portions of the sheets fed from the respective roll sheets to the common conveyance path at the sheet joining portion.

  However, since the roll paper itself does not rotate in the reverse rotation direction, the rewound paper portion stays in a state of being bent or forcibly folded between the roll paper main body and the conveying roller device, and deformation such as folds is caused. Are formed, causing white spots during image formation, forming wrinkles due to moisture absorption, and causing jamming.

  Japanese Patent Application Laid-Open No. 2004-133260 describes a configuration in which when a paper on the roll paper side is rewound after the paper drawn from the roll paper is cut, the roll paper main body is reversed to prevent the paper from loosening. Specifically, a forward / reverse drive unit connected to the paper feed roller via a one-way clutch, and a drive path connected to the drive unit via a transmission path different from the one-way clutch. In the sheet feeding device having the drive transmission means that can be released, the drive transmission means includes a swinging member that is pivotally supported toward the gear of the roll paper holder, and the rotation member receives a rotational torque from the driving unit. The main gear is engaged with the gear of the roll paper holder and the gear is engaged with the gear of the roll paper holder by pivoting in the opposite direction. Is to be canceled. However, since the roll paper is reversely rotated by the driving force from the motor, the one disclosed in Patent Document 1 has a disadvantage that the structure for reverse rotation has to be added and the mechanism is complicated. .

  Japanese Patent Laid-Open No. 2004-151867 discloses a paper tube of a roll paper in order to rewind the slack of the paper by reversing the roll paper when the paper fed out after cutting the paper drawn from the roll paper is rewound. Rotation load means is provided on the shaft portion of the spool that supports the rotation and can be rotated in the feed-out direction and the rewind direction, and the drive in the direction of feeding the roll paper into the gear train that transmits the drive from the drive source to the rotation load means is One-way transmission means for transmitting only the driving in the rewinding direction without transmitting is provided.

  Further, in Patent Document 3, a plurality of receiving rollers that rotatably support the flange member are provided so that the diameter of the flange member is made smaller than the maximum outer diameter of the roll paper, and the roll paper is obtained by rotating the receiving roller in the reverse direction. The structure which rewinds is adopted. In this configuration, one in which a rewinding mechanism is built in one of the receiving rollers is described.

  Conventionally, a spool method or a flange method has been adopted to hold roll paper in order to hold roll paper of various sizes when holding the roll paper. The spool method used in the ones described in Patent Document 1 and Patent Document 2 has a drawback that it is necessary to pass a long spool through the paper tube of the roll paper, and the user's operability is poor (very difficult to handle). However, when a rewinding mechanism or the like is provided, there is an advantage that the roll paper itself can be easily driven by providing a drive transmission mechanism in the spool, and it has been actively adopted when providing the rewinding mechanism. It was.

  On the other hand, the flange method disclosed in Patent Document 3 has very high user operability because the flange is inserted and held in the paper tube from both sides of the roll paper of any size.

  Here, in the case of the flange type, in order to transmit the driving force directly to the roll paper, the diameter of the flange is made larger than the maximum outer diameter of the roll paper and the driving force is transmitted to the outer diameter of the flange paper, or during paper conveyance There is only one way of transmitting the driving force to the flange on the side other than the reference end side by taking the reference in the width direction at the edge of the paper. When the outer diameter of the flange is increased, the machine size itself is increased due to the increased flange diameter, and there is a drawback that the roll paper must be set while lifting one side. There are also restrictions on the layout due to the increased flange diameter. Further, if the reference in the width direction at the time of conveyance is set to the edge of the sheet, there is a possibility that problems may occur in the conveyance quality such as wrinkles, shifts and skews when conveying a long sheet.

  Further, the one described in Patent Document 3 adopting the flange method has a rewinding mechanism built in one of the receiving rollers, but the accumulated force of the winding spring is realized when the roll paper is fed, and the winding is performed. When rewinding, the flange member is rotated in the rewinding direction by the repulsive force of the spring. When the rewinding speed is constant, the remaining amount of roll paper is reduced and the outer diameter of the roll paper and the diameter of the receiving roller or flange When the ratio of the member diameters changes, the slip amount of the receiving roller must be increased. Further, since the winding state of the winding spring at the time of feeding defines the limit of the rewinding amount, there is a problem that the roll paper cannot be rewound for a long distance.

  Therefore, the present invention has good usability, can prevent the slack of the paper even at the time of high-speed intermittent conveyance of the paper, can be stably conveyed without skew, and has a long life and simple. It is an object of the present invention to provide a recording medium sending apparatus and an image forming apparatus having a configuration.

  The invention of claim 1 includes a pair of flange members that are respectively inserted into both ends of the roll paper and have a diameter smaller than the maximum outer diameter of the roll paper, and a plurality of support rollers that rotatably support the both flange members. In a recording medium delivery apparatus comprising: a support roller set; a paper feed roller that feeds the recording medium from the roll paper to a printing unit; and a drive source that drives the paper feed roller. The roller set is configured to be movable in the longitudinal direction of the roll paper, and engages with at least one of the support roller sets to drive the flange member in the rewind direction of the recording medium for a predetermined time. A recording medium tension applying unit that is installed between the roller and the printing unit and applies a tension to the recording medium by pressing the recording medium and changing a recording medium conveyance path length; The return roller has at least a length corresponding to the maximum separation distance of both support roller sets, and transmits the rotational driving force when the rewind roller is driven in the rewind rotation, while driving in the reverse rotation and the reverse rotation. When it is done, it is connected to the driving source through a driving force switching means that cuts off the rotational driving force, and during the operation of the printing unit, while stopping the conveyance of the recording medium at the location related to the printing operation, The recording medium feeding device is characterized in that the drive source performs forward and reverse operations alternately.

  According to a second aspect of the present invention, in the recording medium delivery device according to the first aspect, the driving force switching means is a one-way clutch disposed between the rewinding roller and the driving source.

  According to a third aspect of the present invention, in the recording medium feeding device according to the first aspect, the driving force switching means is provided in a rewinding roller, and the driving source is set in a direction to drive the paper feeding roller in the medium feeding direction. A rotation switching mechanism that rotates the rewinding roller in a direction to rotate the recording medium in a direction to rewind the recording medium when rotating, and provides reverse rotation driving to the rewinding roller when the drive source rotates in the reverse direction to the normal rotation. It is characterized by being.

  According to a fourth aspect of the invention, there is provided the recording medium delivery device according to any one of the first to third aspects, further comprising braking means for suppressing rotation of the flange member.

  According to a fifth aspect of the present invention, there is provided an image forming apparatus comprising the recording medium delivery device according to any one of the first to fourth aspects.

  According to the present invention, at least one of the support roller groups is configured to be movable in the longitudinal direction of the roll paper, and the flange member is engaged with at least one of the support roller groups. Installed between the rewinding roller that drives in the rewinding direction of the recording medium for a predetermined time and the printing unit, presses the recording medium to change the recording medium conveyance path length and applies tension to the recording medium. Recording medium tension applying means, and the rewinding roller has at least a length that coincides with the maximum separation distance of both support roller sets, and generates a rotational driving force when the rewinding roller is driven for rewinding rotation. When it is driven in one reverse rotation and reverse rotation, it is connected to the drive source via a driving force switching means that cuts off the rotational driving force, and is related to the printing operation during the operation of the printing unit. As the drive source alternately performs forward and reverse operations while stopping the conveyance of the recording medium at the location, it has good usability and the slack of the recording medium occurs even during high-speed intermittent conveyance of the recording medium In addition, it is possible to prevent the occurrence of skew and to stably convey the recording medium, and to achieve a simple configuration with a long life.

1 is a schematic diagram illustrating an overall configuration of a printer according to an embodiment. It is a side view which expands and shows the roll paper feeder which concerns on an Example. It is a front view which expands and shows the principal part of the roll paper feeder which concerns on an Example. It is a perspective view which shows the principal part of the roll paper feeder which concerns on an Example. It is a schematic diagram which shows operation | movement of the roll paper feeder which concerns on an Example. FIG. 2 illustrates a roll sheet feeding device according to a second embodiment, in which (a) is a schematic diagram illustrating a forward rotation, and (b) is a schematic diagram illustrating a reverse rotation.

  The recording medium delivery device according to the present invention includes a pair of flange members that are respectively inserted into both ends of the roll paper and have a smaller diameter than the maximum outer diameter of the roll paper, and a plurality of supports that rotatably support the both flange members. A recording medium delivery apparatus comprising: a support roller set made of a roller; a paper feed roller that feeds the recording medium from the roll paper to a printing unit; and a drive source that drives the paper feed roller. One support roller set is configured to be movable in the longitudinal direction of the roll paper, and engages with at least one of the support roller sets to drive the flange member in the rewind direction of the recording medium for a predetermined time. Recording medium tension applying means installed between the rewinding roller and the printing unit to press the recording medium and change the recording medium conveyance path length to apply tension to the recording medium The rewinding roller has at least a length corresponding to the maximum separation distance of both support roller sets, and transmits the rotational driving force when the rewinding roller is driven to rewind, while the rewinding rotation When driving in the reverse direction, the recording medium is connected to the driving source via a driving force switching means that cuts off the rotational driving force, and the recording medium is conveyed at a location related to the printing operation during the operation of the printing unit. The driving source is alternately rotated forward and reverse while stopping the operation.

  Here, the maximum outer diameter of the roll paper is the outer diameter when the roll paper is not used. Further, since each flange member is rotatably supported by a support roller set constituted by at least two support rollers, the two flange members inserted into both ends of the roll paper are rotatably supported. In order to cope with roll papers having different widths, at least one of the two support roller sets that support the flange member is moved in the longitudinal direction of the roll paper. Since the length of the rewinding roller is longer than the maximum separation distance of a pair of support roller sets, the rewinding roller contacts the support roller even when using the maximum width roll paper that is expected to be used. So you can rewind. A one-way clutch is disposed on the rewinding roller, and the one-way clutch transmits a driving force when the rewinding roller is driven in the rewinding direction by a driving source, and the driving force is cut off during the reverse rotation. .

  In such a configuration, during the printing operation, the recording medium conveyance at the printing unit is stopped, and the recording medium feeding motor is rotated forward and backward to prevent the recording medium from slacking without complicating the apparatus and control. Thus, stable recording medium conveyance can be performed.

  In the present invention, a rotation switching mechanism can be used instead of the one-way clutch. The rotation switching mechanism is provided in the rewinding roller, and rotates the rewinding roller in the direction of rewinding the recording medium when the drive source rotates forward in the direction of driving the paper feed roller in the medium feeding direction. When the drive source rotates in the reverse direction to the forward rotation, the reverse rotation drive is given to the rewinding roller. According to this example, the control is not complicated, and the recording medium slack removal effect can be improved and the recording medium can be stably conveyed.

  Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, an ink jet printer will be described as an example of the image forming apparatus. FIG. 1 is a schematic diagram illustrating the overall configuration of the printer according to the embodiment. This printer includes three roll paper feeders 40 as medium delivery devices. Two roll sheet feeders 40 are arranged in the upper part and one in the lower part. The upper two roll sheet feeders 40 are arranged in the upper roll tray 8 and the lower one roll sheet feeder 40 is arranged in the lower roll tray. 9 is arranged. In the roll paper feeding device 40, one flange member 1 is attached to each end of the paper tube of the roll paper 2, and a total of two sheets are attached as a pair. Here, the outer diameter of the flange member 1 is set smaller than the maximum outer diameter of the roll paper (roll paper diameter when not in use). The roll paper 2 on which the pair of flange members 1 and 1 are mounted is set on a flange cradle 3 and is fed out by a paper feed roller 6 driven by a paper feed motor 7 described later and its opposing roller 41, The sheet is conveyed to a paper tension applying unit which is a recording medium tension applying unit formed in the recording medium conveying path. The sheet tension applying means is basically composed of a swingable conveyance guide 10 and a spring 11 on the inner peripheral side, and also serves as a buffer function for the tension of the fed sheet.

  A registration roller 13 and a registration pressure roller 14 driven by the registration motor 12 are arranged further downstream of the sheet tension applying means, and are conveyed between the registration roller 13 and the registration pressure roller 14. The sheet is conveyed onto a platen plate on the chamber 18 that is a printing unit.

  A suction fan 19 is disposed under the chamber 18. The suction fan 19 creates a negative pressure in the chamber 18, and the sheet is sucked onto the platen plate from a plurality of holes provided in the platen plate. Flatness is maintained. A carriage 16 on which a head 15 for ejecting ink is mounted is disposed on the platen plate. The carriage 16 reciprocates in the width direction of the paper along the main scanning stay 17 so that the ink is placed on the platen plate. The ink is ejected toward the paper to form an image on the paper. Each time the carriage 16 moves corresponding to the width of the head 15, the paper is intermittently sent out by a predetermined length from the registration roller 13. When the image formation is completed, the paper is cut to a predetermined length by the cutter 20. The paper is conveyed along the reverse paper guide 21 and discharged to the paper discharge tray 22.

  Hereinafter, the roll sheet feeder 40 according to the embodiment will be described. 2 is an enlarged side view showing the roll sheet feeding device according to the embodiment, FIG. 3 is an enlarged front view showing a main part of the roll sheet feeding device according to the embodiment, and FIG. 4 is a roll feeding device according to the embodiment. It is a perspective view which shows the principal part of a paper apparatus. The flange receiving base 3 is provided with a front roller 5 and a rear roller 24 as a support roller set. The flange members 1 and 1 fitted on both sides of the paper tube of the roll paper 2 are respectively connected to the front roller 5 and the rear roller. 24. Thereby, the roll paper 2 is set on the flange cradle 3. The flange cradle 3 moves in the roll paper longitudinal direction at least one of a pair of support rollers including a front roller 5 and a rear roller 24 arranged on both ends of the roll paper so that the set position in the longitudinal direction can be changed according to the roll paper size. It is configured as possible. As shown in FIG. 3, the rewinding roller 4 is set to be longer than the width of the maximum roll paper that can be fed, and even when changing the width dimension of the roll paper, it contacts the rewinding roller 4. Since the set of the rotating front roller 5 and the rear roller 24 is only slid and moved in the longitudinal direction, the drive can be stably transmitted without changing even after the roll paper setting position of the flange receiving base 3 is changed.

  Further, the flange members 1 and 1 are provided with a braking device 26. The braking device 26 includes an arm portion 26a that is driven to swing, and a sliding contact portion 26b that is disposed at the tip of the arm portion 26a and that is in sliding contact with the outer periphery of the flange members 1 and 1 to brake the flange members 1 and 1. The rotation of the flange members 1 and 1 can be suppressed at a predetermined timing.

  As shown in FIGS. 2 and 3, the front roller 5 is in contact with the outer periphery of the flange member 1 and is also in contact with the rewinding roller 4. The rewinding roller 4 is connected to a one-way clutch 27, and the one-way clutch 27 is transmitted through a concentric roller 6 a of the paper feeding roller 6, a paper feeding motor 7 capable of forward and reverse rotation, and a timing belt 42. It has become. The one-way clutch 27 interrupts the driving force from the paper feed motor 7 when rotating in the paper feed direction, and transmits the driving force to the rewind roller 4 when rotating in the rewind direction. Tension can be applied to increase the rewinding accuracy. The transmission of the rotational driving force to the rewind roller 4 and the paper feed roller 6 of the paper feed motor 7 may use a known gear train instead of the timing belt 42.

  When feeding the paper, the paper feed motor 7 rotates forward, the timing belt 42 is driven, the paper feed roller 6 is rotated clockwise in FIG. 2, and the paper is fed from the roll paper 2. At that time, the front roller 5 rotates counterclockwise in accordance with the clockwise rotation of the roll paper 2 and the flange member 1. Here, since the forward rotation of the paper feeding motor 7 and the timing belt 42 is not transmitted to the rewinding roller 4 by the one-way clutch 27, the rewinding roller 4 is in a direction against the counterclockwise rotation of the front roller 5. It does not rotate, but basically is rotated by the front roller 5. At this time, some slip occurs between the front roller 5 and the rewinding roller 4 and between the front roller 5 and the flange member 1, and no slack occurs between the paper feed roller 6 and the roll paper 2.

  On the other hand, when the paper is rewound, the paper feed motor 7 and the timing belt 42 are rotated in the reverse direction to rotate the paper feed roller counterclockwise in FIG. At this time, the one-way clutch 27 transmits the driving force of the paper feed motor 7 to the rewinding roller 4, so that the rewinding roller 4 rotates counterclockwise to rotate the front roller 5 clockwise and according to the rotation of the front roller 5. The flange member 1 rotates counterclockwise, and the roll paper 2 also rotates counterclockwise, and the leading edge of the paper fed from the roll paper 2 is returned from the cutter 20 to a predetermined standby position. In this example, the standby position at the front end of the sheet is set at two positions, which are usually the nipping positions between the registration roller 13 and the registration pressure roller 14, and subsequent image formation is performed on a sheet of another size. In this case, the position is set on the upstream side of the paper joining portion from each roll paper, and it is recognized by a known sensor that the front end of the paper comes to a predetermined standby position.

  At the time of this rewinding, the paper feed roller 6 and the rewind roller 4 basically rotate at a constant speed. However, the roll paper 2 rotated through the front roller 5 and the flange member 1 by the rotation of the rewind roller 4 In other words, the diameter becomes narrower as it is used, and the amount of paper taken up (winding length) gradually decreases. That is, the larger the outer diameter of the roll paper 2, the larger the amount of winding per rotation, so that when the paper roll is rewound with a small remaining amount, the paper feed roller 6, the rewinding roller 4, the front roller 5, If the relative size of each rotating body is set so that the sheet slack does not occur due to the rotation of the flange member 1, it depends on the amount of rotation of the paper feed roller 6 and the rewinding roller 4 while the diameter of the roll paper 2 is large. A sheet length longer than the sheet rewinding amount is taken up by the rotation of the roll paper 2, and surface rubbing occurs between each of the rewinding roller 4, the front roller 5, and the flange member 1. It is rewound while rubbing.

  As described above, the roll paper feeding device 40 according to the embodiment performs intermittent conveyance when the paper is fed out. However, for the purpose of improving the image printing speed, when the paper is intermittently conveyed, the roll paper feeding device 40 is intermittent each time. It is necessary to stop the conveyance in a short time, and a heavy roll paper may be rotated too much. As a result, sheet slack occurs between the roll and the sheet feed roller, causing skew during sheet conveyance and adversely affecting motor control.

  In order to prevent this, the braking force applied to the rewinding roller can be increased, but this causes an increase in the motor load, and the motor needs to be enlarged, resulting in a large energy loss. Although a brake mechanism that operates at a predetermined timing can be added, it is difficult to control the brake in a short time and in a timely manner, resulting in a complicated device. In the present embodiment, this problem is solved by performing the sheet slack eliminating operation without increasing the braking force and without adding a new brake mechanism.

  The operation of the roll sheet feeding device according to this embodiment will be described below. FIG. 5 is a schematic diagram illustrating the operation of the roll sheet feeding device according to the embodiment. When performing the intermittent conveyance operation of the sheet, the registration roller 13 and the registration motor 12 having relatively small inertia can be stopped in a short time. In contrast, the paper feed roller 6 and the paper feed motor 7 that pull the roll paper 2 having a larger inertial force are controlled separately from the registration motor 12, and the rise and fall are controlled at a gentler timing.

  In consideration of higher-speed intermittent sheet feeding operation, the registration motor 12, the registration roller 13, the paper feed motor 7, and the paper feed roller 6 need to rise and fall in a shorter time. When performing such control, the roll paper 2 is also required to have the same rapid acceleration and sudden stop. However, the roll paper cannot be stopped by the brake caused by the frictional force of the rewinding roller 4 and the front roller 5, and the roll paper rotates too much. As a result, the paper is loosened between the roll paper 2 and the paper feed roller 6 (FIG. 5A). If the intermittent conveyance of the paper is started again in a state where the paper is slack in this way, the load applied to the paper feed motor 7 suddenly fluctuates greatly, which hinders motor control. Further, the slack of the paper also leads to paper skew and adversely affects the print quality. While the first intermittent paper conveyance is completed and the printing operation is being performed, it is necessary to stop the paper downstream from the registration roller 13, but moving the paper in the conveyance path upstream from the registration roller 13 does not perform printing. Does not affect the operation.

  Therefore, it is only necessary to feed the paper upstream from the registration roller 13 during the printing operation, perform rewinding, and remove the slack of the paper. First, the paper is fed by the paper feed roller while the registration roller 13 is stopped. At this time, the brake device 26 brakes and locks the flange member 1 (rewinding roller 4). As a result, the roll paper 2 does not rotate, the paper is sent out from the paper slack portion, and the amount of slack is reduced. At this time, the conveyance guide 10 moves upward. (FIG. 5B). Next, when the paper feed motor 7 is reversed and the rewind roller 4 is driven, the roll paper is rewound at a speed higher than that of the paper feed roller 6 without slipping, and the amount of looseness is further reduced. At this time, the sheet moves to the conveyance guide 10 side (FIG. 5C), and finally the sheet is fed by the sheet feeding roller 6 until the conveyance guide 10 returns to the original position. As a result, there is no slack in the paper (FIG. 5D).

  As described above, according to this embodiment, it is possible to remove the slack of the sheet only by rotating the sheet feeding motor forward and backward during the printing operation. When the amount of slack is small, the slack disappears during this operation. If the amount of slack is large, this operation may be repeated a plurality of times.

  Next, a roll paper feeder according to a second embodiment will be described. FIGS. 6A and 6B show a roll paper feeder according to the second embodiment, in which FIG. 6A is a schematic diagram showing the forward rotation, and FIG. 6B is a schematic diagram showing the reverse rotation. In the first embodiment described above, the one-way clutch 27 is built in the rewinding roller 4 and is locked and braked during delivery. Here, if the rewinding roller 4 is always reversely rotated as a separate drive by a separate motor, the roll paper 2 is braked, and the roll paper 2 is always applied with a reverse rotational force even after being stopped, so the paper is slack. Even if it occurs temporarily, it can be eliminated. However, in this method, it is necessary to provide a motor and a drive system exclusively for the rewinding roller, which leads to complication of the apparatus and an increase in cost.

  Therefore, in this embodiment, a rotation switching mechanism that switches the drive transmission path to the rewinding roller 4 between the forward rotation and the reverse rotation without increasing the number of motors is provided, and the reverse rotation direction is always provided in the rewinding roller 4. The driving force is applied. That is, in this example, the driving force transmitted from the drive gear 33 driven by the paper feed motor 7 which is a drive source is the two paths of the gear train (paths A1, A2, A3, paths B1, B2, B3, B4). ) Is transmitted to the rewind roller drive gear 34. That is, the gear train includes a first stage gear 28, a second stage gear 29, and an idle gear 30. The first gear 28 is a gear 28a meshed with the drive gear 33 and a gear 28b meshed with the rewinding roller drive gear 34, which are coaxially connected via a one-way clutch 28c. Here, the one-way clutch 28c transmits only the clockwise rotation in the figure, and when the drive gear 33 rotates in the forward direction (counterclockwise: arrow A1 in FIG. 6 (a)), the rewind roller drive gear 34 is rewinded. Drive counterclockwise (counterclockwise: same arrow A3).

  The second first gear 29 is a gear 29a meshed with the drive gear 33 and a gear 29b meshed with the idle gear 30 connected coaxially via a one-way clutch 29c. Here, the one-way clutch 29c transmits only the counterclockwise rotation in the figure, and when the drive gear 33 is reversely rotated (counterclockwise: arrow B1 in FIG. 6B), the rewinding roller is driven via the idle gear 30. The gear 34 is rotationally driven in the rewinding direction (counterclockwise: same arrow B4).

  As described above, according to this example, the rewind roller drive gear 34 rotates counterclockwise, that is, the rewind direction, regardless of whether the drive gear 33 is rotating forward or backward. The driving force in the direction seems to be applied, and the slack of the paper can be absorbed. Note that the same effect can be obtained by using the second first-stage gear 29 as a normal gear and using a gear with a clockwise one-way clutch instead of the idle gear 30. Further, the same effect can be obtained by using two electromagnetic clutches instead of the two one-way clutches 28c and 29c and switching the clutches during normal rotation and reverse rotation.

1: flange member 2: roll paper 3: flange receiving base 4: rewind roller 5: front roller 6: paper feed roller 6a: concentric roller 7: paper feed motor 8: upper roll tray 9: lower roll tray 10: transport guide 11: Spring 12: Registration motor 13: Registration roller 14: Registration pressure roller 15: Head 16: Carriage 17: Main scanning stay 18: Chamber 19: Suction fan 20: Cutter 21: Reverse paper guide 22: Paper discharge tray 24: Rear roller 26: braking device 26a: arm portion 26b: sliding contact portion 27: one-way clutch 28: first-stage gear 28a: gear 28b: gear 28c: one-way clutch 29: second first-stage gear 29a: gear 29b: gear 29c: one-way clutch 30 : Idle gear 33: Drive gear 34: Rewind roller drive gear 40: Roll feed 41: counter roller 42: Timing belt

Japanese Utility Model Publication No. 5-85747 JP 2006-248863 A JP 2003-276264 A

Claims (5)

A pair of flange members that are respectively inserted into both ends of the roll paper and have a diameter smaller than the maximum outer diameter of the roll paper, a support roller set including a plurality of support rollers that rotatably support the both flange members, and the roll In a recording medium delivery apparatus comprising a paper feed roller for feeding a recording medium from paper to a printing unit, and a drive source for driving the paper feed roller,
At least one of the support roller sets is configured to be movable in the longitudinal direction of the roll paper,
It is installed between the printing unit and a rewinding roller that engages with at least one support roller of the support roller set and drives the flange member in the rewinding direction of the recording medium for a predetermined time. A recording medium tension applying means that presses the medium and changes the recording medium conveyance path length to apply tension to the recording medium;
The rewinding roller has at least a length corresponding to the maximum separation distance of both support roller sets, and transmits a rotational driving force when the rewinding roller is driven to rewind rotation, while rotating reversely with rewinding rotation. When being driven by, connected to the driving source through a driving force switching means for cutting off the rotational driving force,
A recording medium sending device, wherein during the operation of the printing section, the forward movement and reverse rotation of the drive source are alternately performed while stopping the conveyance of the recording medium at a location related to the printing operation.   2. The recording medium feeding apparatus according to claim 1, wherein the driving force switching means is a one-way clutch disposed between the rewinding roller and the driving source.   The driving force switching means is provided on the rewinding roller, and rotates the rewinding roller in the direction of rewinding the recording medium when the drive source rotates forward in the direction of driving the paper feed roller in the medium feeding direction. 2. The recording medium feeding device according to claim 1, wherein the recording medium feeding device is a rotation switching mechanism that rotates in a direction and applies a reverse rotation drive to the rewind roller when the drive source rotates in the reverse direction to the normal rotation.   4. The recording medium feeding device according to claim 1, further comprising a braking unit that suppresses rotation of the flange member.   An image forming apparatus comprising the recording medium delivery device according to claim 1.