JP4108221B2 - Printing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printing apparatus provided with a paper transport mechanism that sandwiches paper between a pair of transport rollers and feeds the paper with frictional force.
[0002]
[Prior art]
In a printing apparatus, a paper transport mechanism that presses a driven roller against a drive roller (a pair of transport rollers) and sandwiches and transports the paper therebetween is often used. The paper transport mechanism feeds the paper by the frictional force between the paper and the roller, and the force to feed the paper is determined by the degree of the pressure contact force of the driven roller against the driving roller.
In the paper transport mechanism of the printer, a skew correction stopper is provided upstream of the platen in the paper transport direction, and the leading edge of the paper collides with this to adjust the skew (skew) of the paper with respect to the transport direction. In many cases, a mechanism is provided. This mechanism applies a slip between the roller and the paper, collides the leading edge of the slanted paper against the stopper, stops feeding that side, and feeds the other side until it collides with the stopper. The tilt is corrected.
[0003]
In other words, the paper transport roller pair gives a rotational moment to the paper to correct the inclination of the paper, but the paper transport roller pair originally has a uniform clamping force so as to feed the paper uniformly in the width direction of the paper, In other words, since a uniform feeding force is applied, when skew correction is performed, slippage between the pair of conveyance rollers and the sheet increases as the side that collides with the skew correction stopper is generated. The clamping force is adjusted.
However, in the conventional pair of paper transport rollers, for example, a first roller that is a driving roller is attached to one driving rotary shaft, and a second roller that is a corresponding driven roller is attached to one driven rotating shaft. Therefore, the adjustment of the clamping force becomes uniform in the width direction of the paper, and it is difficult to obtain an appropriate clamping force that gives sufficient sliding on one side and sufficient feeding on the other side. In addition, when the respective shafts are closer to each other than the set value on one side and are mounted farther from each other than the set value on the other side, the sheet feeding force increases on the closer side. For this reason, if the large side of the paper feeding force coincides with the side that must give sufficient slip, the slip becomes insufficient.
The paper may jam at the skew correction location or the skew correction may be incomplete.
[0004]
In the printing apparatus described in Utility Model Registration No. 2508855, a soft auxiliary roller 9 made of sponge or the like is attached to the outer periphery of the paper feed roller 1 (driven roller) pressed against the feed roller 5 (drive roller), and the paper The paper feed force by the pair of transport rollers is weak by the auxiliary roller up to the stopper for skew correction, and thereafter, the paper feed roller 1 is strongly pressed against the feed roller 5 to crush the auxiliary roller 9 and the strong feed force. Although a paper transport configuration is adopted, this configuration weakens the paper transport force during skew correction and easily causes slippage. After skew correction, the skew correction is performed simply by returning to the normal transport force. It is not a solution that properly gives the moment to rotate the paper required in the process.
[0005]
[Problems to be solved by the invention]
In the present invention, when skew correction is performed, a sheet is provided with a sheet transport mechanism that provides a sheet with sufficient slippage on one side in the width direction and sufficient feeding on the other side so that the sheet skew correction is performed smoothly. It is an object to provide a device.
[0006]
[Means for Solving the Problems]
The printing apparatus includes a main body frame, a paper transport table, a platen, a print head, a paper transport roller pair, and a skew correction stopper. The paper transport table has a paper transport surface and is fixed to the main body frame, and forms a straight paper transport path on the paper transport surface. The platen is disposed so as to be exposed from the sheet conveying surface of the sheet conveying table to the sheet conveying path, and the print head is disposed so as to face the platen. The pair of paper transport rollers are configured to sandwich and feed paper between a pair of rollers, and most of them are composed of a driving roller and first and second rollers that are driven rollers pressed against the driving roller. Provide a pair. These are independently pressed with a force set on at least one of the other. The skew correction stopper is provided between the platen and the conveyance roller pair in the sheet conveyance direction, and can advance and retreat on the sheet conveyance path. As a result, the edge of the paper sent by the pair of transport rollers collides with the skew correction stopper to correct the skew, and then the skew correction stopper is retracted from the paper transport path, and the skew corrected paper is placed on the platen. Sent.
[0007]
Each pair of paper transport rollers can adjust the pressure contact force between the first roller and the second roller. In general, the drive roller is pivotally supported on the paper transport table, and the driven roller is rotatably supported by the holder and the holder is swingably supported by the main body frame. A coil spring or the like is provided between the holder and the main body frame. The urging member is provided. The driven roller is pressed against the driving roller by the biasing member.
In order to bias the holder, the movable member may be supported on the main body frame, and the biasing member may be disposed between the movable member and the holder. When the movable member moves relative to the main body frame, the distance between the movable member and the holder is changed, and the pressure contact force of the driven roller with respect to the drive roller is adjusted.
In order to drive the movable member, a cam provided between the main body frame and the movable member may be used, or the cam may be driven by a stepping motor.
Further, the holder and the movable member are assembled to a sub-frame separate from the main body frame, and the sub-frame is supported so as to be swingable to the main body frame. May be configured to leave.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a sheet conveying mechanism of a printing apparatus 1. A sheet conveying table 5 having a main frame 2 and a sheet conveying surface 4 fixed to the frame 2 to form a straight sheet conveying path 3, a platen 6, a print head 7, a first paper conveyance roller pair 8, a second paper conveyance roller pair 9, and a skew correction stopper 10. In FIG. 1, reference numeral M1 denotes a motor, and reference numerals G1 to G9 denote power transmission gears, which constitute a gear link of the motor M1. However, the code | symbol has shown the shaft center, and detailed description, such as a drive side gear and a driven side gear, is abbreviate | omitted. The gear G2 is an idle gear. Reference numeral T is a tractor for continuous paper, and reference numeral F is a flapper for switching the paper transport path 3 between a cut paper mode and a continuous paper mode. In the figure, cut sheets are used. Reference numeral C denotes a control unit provided in the printing apparatus 1 that drives each part of the printing apparatus and its timing, and processes a print signal and print data sent from a parent device such as a so-called personal computer.
[0009]
The main body frame 2 serves as a substrate on which the mechanism as the printing apparatus 1 is assembled, and is formed firmly by pressing a steel plate. The paper transport table 5 (FIG. 2) is also a pressed product of a steel plate and has a top surface that is a substantially flat paper transport surface 4. A hole 11a for the platen 6 is provided with the first and second paper transport roller pairs 8,9. Holes 11b and 11c, and a hole 11d for the skew correction stopper 10 are provided. Reference numeral 11e is a hole for projecting the paper position detection sensors S1 to S4, and there are four holes in FIG. The sensors S1 to S4 are rotated below the paper transport surface 4 at the leading edge of the paper, and return to the original position when the paper passes. Sensor S1 detects the leading edge of the paper, and sensors S2 and S4 detect the trailing edge of the paper. Sensors S2 and S3 detect the degree of skew of the paper.
[0010]
The platen 6 is pivotally supported at the lower part of the sheet conveying surface 4 and is driven by a gear link of the motor M1. The upper part of the peripheral surface is exposed to the hole 11a of the paper transport table 5 at substantially the same position as the paper transport surface 4. The print head 7 is arranged on the upper part of the platen 6 so as to oppose the platen 6, and a print gap is formed between the print head 7 and the peripheral surface of the platen 6.
The first paper transport roller pair 8 is disposed upstream of the platen 6 in the paper transport direction, and the second paper transport roller pair 9 is disposed downstream of the platen 6, and the first paper transport roller pair 8. Includes a driving roller 12 (first roller) and a driven roller 13 (second roller), and the second sheet conveying roller pair 9 includes a driving roller 14 and a driven roller 15. Both the drive rollers 12 and 14 are pivotally supported at the lower part of the sheet conveying surface 4 and are exposed to the sheet conveying surface 4 from the holes 11b and 11c, respectively, and are driven by a gear link of the motor M1.
[0011]
The driven roller 13 of the first paper conveying roller pair 8 is pivotally supported on the holder 16 as shown in FIGS. The holder 16 is a molded product of synthetic resin, and a horizontal portion 17 that pivotally supports the driven roller 13 and a vertical portion 19 whose upper end is pressed by a coil spring 18 (biasing member) are integrally formed. In this embodiment, there are six first paper conveyance roller pairs 8, and each driven roller 13 is individually supported by a holder 16. The six holders 16 are pivotally supported on the sub-frame 20 at corners where the vertical portion 19 and the horizontal portion 17 are individually connected (FIG. 6), and the driven roller 13 side is located above and below the paper transport surface 4. It can be rotated. That is, it is the structure which pressed independently at least one of each pair of rollers with the force set with respect to the other.
[0012]
In this embodiment, the holder 16 (FIG. 6) is integrally provided with a sheet guide portion 36 having a curved lower surface on both sides of a portion where the driven roller 13 of the horizontal portion 17 is pivotally supported, and lifts the passing sheet. It is preventing. A presser claw 37 is pivotally supported at this portion, and only when the paper moves in the print gap direction, it comes into contact with the paper and prevents the paper from lifting. That is, the presser claw 37 has a structure in which when the presser claw 37 is rotated in the print gap direction, the lower end portion protrudes toward the paper transport surface 4 side and further rotation is prevented, and the presser claw 37 can freely rotate in the reverse direction. The lower end is moved and retracted from the sheet conveying surface.
[0013]
Further, a pressing spring 39 is disposed on a portion 38 that protrudes adjacent to the horizontal portion 17 of the subframe 20. The holding spring 39 first bends the sharpened tip portion of the spring wire bent into a V shape and both ends on the open side, then bends both ends bent upward to the outside horizontally, and has a V shape. The middle part of the shape is bent downward shallowly. The tip of the holding spring 39 is engaged with the protruding portion 38 from above, and the open horizontal sides are passed from below to the engaging hole 40 provided in the base of the protruding portion. Is engaged with the upper surface.
The holding spring 39 is accommodated in the engagement hole 40 in a state where the spread on the open side is compressed. For this reason, the presser spring 39 is always urged downward by its own spring force at a portion where the upward rising portion on the open side contacts the periphery of the engagement hole 40, and prevents the sheet from floating at the intermediate portion. To do.
The coil spring 18 is disposed between the movable member 21 and the upper portion of the vertical portion 19. The movable member 21 is located on the inner surface side of the rear wall of the subframe 20, and the lower portions of both left and right ends are supported by the subframe 20 so as to be swingable.
[0014]
The movable member 21 (FIGS. 3 and 4) is a plate-like member that is long on the left and right, which is obtained by pressing a steel plate, and a swash plate-like cam follower 22 is integrally formed at one end. Further, six coil springs 18 corresponding to each of the holders 16 are attached to the upper side portion in a row, and claw receiving holes 23 are formed on the lower side portion on the left and right sides.
The sub-frame 20 is for assembling the holder 16, the movable member 21, the coil spring 18, and the like integrally and attaching the whole to the main body frame 2 so as to be swingable. A claw 24 to be inserted into 23 is provided, and engaging protrusions 25 are provided on the upper left and right. The sub-frame 20 is mounted so as to be rotatable about the upper part of the engaging protrusion 25 by engaging the left and right engaging protrusions 25 with protrusions 26 provided on the main body frame 2. The protrusion 26 is a swing shaft of the subframe 20. Reference numeral 27 denotes a return spring for returning the subframe 20 to the original position.
It should be noted that at the position where the sub frame 20 is engaged with the protrusion 26 of the main body frame 2 and the driven roller 13 of the holder 16 is pressed against the driving roller 12, the axes of the protrusion 26 , the driven roller 13 and the driving roller 12 are in a straight line. is there. That is, the swing axis of the sub-frame 20 is provided on the main body frame 2 so that the direction in which the driven roller 13 contacts or separates from the drive roller 12 is a contact direction parallel to the paper transport direction of the drive roller 12. is there.
[0015]
A stepping motor 28 (FIG. 3) is attached to the subframe 20 with a screw on one end on the inner side, on the side where the cam follower 22 of the movable member 21 is formed. A disk having a pin 28 a (FIG. 4) fixed at an eccentric position is attached to the output shaft, and the pin 28 a contacts the cam follower 22 of the movable member 21. That is, the cam follower 22 and the pin 28 a constitute a cam mechanism provided between the main body frame 2 and the movable member 21, and this cam mechanism is driven by the stepping motor 28. The printing apparatus 1 includes a control unit C, a selection button for selecting a paper type, and pressure force data corresponding to the paper type in the control unit C. The stepping motor 28 rotates a predetermined angle according to the selected paper. Then, the movable member 21 is rotated with respect to the main body frame 2.
[0016]
The driven roller 15 of the second pair of paper transport rollers 9 can be adjusted in two steps with respect to the driving roller 14 and is always pressed with a substantially constant pressure contact force. The pressure contact force is generated by an urging member such as a spring disposed on the support portion of the main body frame 2 and the driven roller 15.
The skew correction stopper 10 (FIG. 5) includes a substrate 29, a rack 30, a blocking piece 31, a pinion 32, and a solenoid 33. The substrate 29 is long to the left and right, and six pinions 32 are pivotally supported so as to correspond to the positions of the holders 16. The rotation surface of the pinion 32 is parallel to the elevation surface of the substrate 29. The rack 30 can move in the left-right direction with respect to the substrate 29, and rack teeth are formed at six locations corresponding to the six pinions. The solenoid 33 is attached to the substrate 29, and the armature 34 is coupled to one end of the rack 30. A coil spring 35 is disposed between one end of the rack 30 and the solenoid 33. The solenoid 33 is a single-acting type that retracts the armature and maintains its position when energized, and the energization timing is under the control of the control unit C.
[0017]
Therefore, in the normal state where the solenoid 33 is not energized, the skew correction stopper 10 moves the rack 30 to the left (a side) by the coil spring 35 and the blocking pieces 31 stand up all at once. , The armature 34 is pulled in, the rack 30 moves to the right (b direction) with respect to the substrate 29, and the blocking pieces 31 are in a state of being collapsed all at once. When the blocking piece 31 is erected, the upper portion protrudes from the hole 11 d provided in the sheet conveying table 5 toward the sheet conveying surface 4.
[0018]
At the time of printing, paper is set, and the type or thickness of the selected paper is taught to the control unit C from the selection button. The control unit C reads data corresponding to the selected sheet from the storage unit, and drives the stepping motor 28 by a necessary angle. Then, the pin 28a rotates and rotates while pressing the cam follower 22 of the movable member 21, thereby changing the angle of the movable member 21 with respect to the main body frame 2. As a result, the degree of compression of the coil spring 18 disposed between the holder 16 and the holder 16 changes, and the force with which the driven roller 13 attached to the horizontal portion 17 of the holder 16 is pressed against the drive roller 12 is adapted to the selected paper. Can be adjusted. Data for driving the stepping motor 28 by a necessary angle is obtained in advance by conducting experiments on the degree of resistance (tension) to the feeding of various papers, the friction coefficient, and the like.
[0019]
When the power of the printing apparatus 1 is turned on, the paper transport mechanism is in an operating state. The solenoid 33 of the skew correction stopper 10 is excited by energization, the armature 34 is pulled in, and the blocking piece 31 is in the retracted state from the paper transport surface 4.
When a sheet is fed by a sheet feeder or by manual feed and the leading edge of the sheet is detected by the sensor S1, the first and second sheet conveying roller pairs 8 and 9 rotate to pinch the sheet, and thereafter the sheet conveying mechanism of the printing apparatus 1 Automatically transports the paper. The tip passes through sensor S2 and sensor S3. At this time, there is a time difference between the passage signal from the sensor S2 and the passage signal from the sensor S3, and when the time difference is equal to or larger than the set value, the control unit C determines that “the paper is tilted” and performs skew correction. That is, the excitation of the solenoid 33 is released to make the armature 34 free, and the rack 30 is pushed out by the coil spring 35. Then, the blocking piece 31 of the skew correction stopper 10 protrudes from the paper conveyance path 3.
[0020]
If the sheet to be fed is inclined with respect to the transport direction, the leading edge first collides with the blocking piece 31 of the skew correction stopper 10 because the leading edge is inclined. However, the first pair of paper transport rollers 8 arranged in parallel with the paper transport roller pair 8 on the side that is collided and prevented from moving (the preceding side) rotates more with greater slippage with the paper. Next, correct the skew of the paper. At this time, although there are a plurality of paper transport roller pairs 8, the action of sandwiching the paper is independent for each individual, and each is not affected by the rotation state of the roller pairs 8 on both sides. For this reason, even if a plurality of paper transport roller pairs 8 are provided and the clamping force for each paper is made uniform, each skew is corrected appropriately between the transport roller pair 8 and the paper. Smooth slippage. As a result, a slip that becomes larger toward the side that collides with the skew correction stopper 10 in the width direction of the paper is smoothly generated, and as a result, a sufficient slip is given to the paper on one side in the width direction of the paper, On the other side, a sufficient feed can be given, and a rotational moment for skew correction can be appropriately given to the paper. As a result, the paper does not jam at the skew correction location, and the skew correction does not become incomplete.
[0021]
At this time, the pressure contact force of the driven roller 13 with respect to the driving roller 12 is appropriately selected by swinging the movable member 21, so that the paper conveying roller pair 8 feeds the paper while sliding between the paper and the paper. Even if it is given, there is no inconvenience of bending the sheet, and after skew correction, the sheet is fed toward the print gap with the selected clamping force. Further, the sheet fed toward the print gap by the first sheet conveying roller pair 8 is prevented from being lifted by the sheet guide part 36 and the holding spring 39 (FIG. 6) provided in the horizontal part 17 of the holder 16. This prevents a situation in which the sensor cannot detect the leading edge of the sheet or the presence of the sheet due to the sheet floating, or the skew correction ends abnormally.
[0022]
The skew correction operation is controlled by a timer, and after a sufficient time for skew correction has elapsed since the leading edge of the sheet has passed the sensor S3, in the embodiment, the skew correction operation ends. With the end of the skew correction operation, the solenoid 33 is energized to retract the armature 34 and retract the blocking piece 31 of the skew correction stopper 10 from the paper transport surface 4.
Thereafter, the sheet advances to the print gap and is printed, and the second sheet conveying roller pair 9 continues to feed and is discharged. When the sensor S4 detects the trailing edge of the sheet, feeding of the next sheet is started.
[0023]
When the time difference between the sheet passing signals from the sensor S2 and the sensor S3 is equal to or smaller than the set value, the control unit C determines that the sheet is not inclined, the excitation of the solenoid 33 is maintained, and the skew correction stopper 10 is blocked. The strip 31 does not protrude from the paper transport surface 4 and the paper advances to the print gap and printing is performed without skew correction.
If, for any reason, a paper jam occurs in the vicinity of the first paper transport roller pair 8, the subframe 20 is manually rotated about the upper projection 26 to the front and six followers are driven. The rollers 13 and 15 can be simultaneously rotated upward to widen the space where the paper exists. As a result, the jammed paper can be easily taken out. At this time, since the driven roller 13 in contact with the driving roller 12 moves in the tangential direction of the paper conveying direction of the driving roller 12, the driving roller 12 is smoothly swung without causing any squeezing or compression between the two rollers. be able to.
[0024]
Above, as an embodiment, the holder 16 and the movable member 21 that axially supports the driven roller 13 and 15 has been described having a structure that is attached to the subframe 20, the subframe is not essential, the holder 16 and the movable The member 21 can also be directly attached to the main body frame 2.
The rotation of the movable member 21 performed to adjust the pressure contact force of the driven rollers 13 and 15 can be performed not by the stepping motor 28 but by a normal motor or servo motor. It can also be done manually, relying on the scale.
Furthermore, the movement of the movable member 21 is not a rotation, but may be other movement forms such as a parallel movement. The coil spring 18 that presses the driven rollers 13 and 15 against the drive rollers 12 and 14 may be another form of spring or other urging means.
[0025]
【The invention's effect】
Although there are a plurality of paper transport roller pairs, the action of pinching the paper is independent for each individual, and each is not affected by the rotation state of the roller pairs on both sides, and when correcting skew, the paper A sufficient slip can be given on one side and a sufficient feed can be given on the other side to appropriately give a rotational moment for skew correction to the paper, so that the paper skew can be corrected smoothly.
When the movable member is moved with respect to the main body frame, the pressure contact force of the plurality of driven rollers with respect to the driving roller can be adjusted simultaneously.
When the sub-frame is moved with respect to the main body frame, a plurality of driven rollers can be moved away from the driving roller all at once, and a space for processing can be made large when a paper jam or the like is necessary.
In the swing range of the subframe, the position where the driven roller is in contact with the drive roller is the lowest, so that no twisting or compression occurs when the subframe is swung.
[Brief description of the drawings]
FIG. 1 is a side view showing an outline of a paper transport mechanism. FIG. 2 is a perspective view of a paper transport stand. FIG. 3 is a perspective view showing a position of a first paper transport roller pair from the back. Side view showing a pair of paper transport rollers (partial cross section)
FIG. 5 is a rear view showing an outline of a skew correction stopper. FIG. 6 is an enlarged perspective view showing a holder portion.
1 printer 2 body frame 3 the paper transportable sending passage 4 sheet conveyance surface 5 sheet conveying table 6 platen 7 print head 8 first sheet transport roller pair 9 second sheet transport roller pair 10 skew correction stopper 11a~11e hole 12 Drive roller 13 Driven roller 14 Drive roller 15 Driven roller 16 Holder 17 Horizontal part 18 Coil spring 19 Vertical part 20 Subframe 21 Movable member 22 Cam follower 23 Claw receiving hole 24 Claw 25 Engagement protrusion 26 Projection 27 Return spring 28 Stepping motor 28a Pin 29 Substrate 30 Rack 31 Blocking piece 32 Pinion 33 Solenoid 34 Armature 35 Coil spring 36 Paper guide part 37 Pressing claw 38 Projected part 39 Pressing spring 40 Engagement hole

Claims (7)

The main body frame 2 and a paper transport base 5 having a paper transport surface 4 fixed to the frame 2 to form a straight paper transport path 3 and the paper transport base 5 are exposed to the paper transport path 3 from the paper transport surface 4. A platen 6 provided opposite to the platen 6, and a pair of paper transport rollers 8 provided on the upstream side of the platen 6 in the paper transport direction and sandwiching and transporting the paper from the front and back. And a skew correction stopper 10 that is provided between the platen 6 and the pair of transport rollers 8 in the transport direction and advances into the paper transport path 3 and can be retracted from the paper transport path 3. pair 8 consists of a drive roller and a driven roller, the drive roller 12 while being axially supported on the sheet transfer table 5, the driven roller 13 against which a plurality of main body off the respective A movable member is provided between the holder 16 and the body frame 2 so that the position of the holder 16 can be adjusted. An urging member that presses the driven roller 13 against the driving roller 12 between the member 21 and the member 21 is provided for each of the printing apparatuses. The main body frame 2 and a paper transport base 5 having a paper transport surface 4 fixed to the frame 2 to form a straight paper transport path 3 and the paper transport base 5 are exposed to the paper transport path 3 from the paper transport surface 4. A platen 6 provided opposite to the platen 6, and a pair of paper transport rollers 8 provided on the upstream side of the platen 6 in the paper transport direction and sandwiching and transporting the paper from the front and back. And a skew correction stopper 10 that is provided between the platen 6 and the pair of transport rollers 8 in the transport direction and advances into the paper transport path 3 and can be retracted from the paper transport path 3. The pair 8 is composed of a driving roller and a driven roller. The driving roller 12 is pivotally supported by the paper transport table 5, and there are a plurality of driven rollers 13. The sub-frame 20 is supported by the main body frame 2 so as to be able to swing, and the sub-frame is swung to support the follower roller. Can be brought into contact with or separated from the driving roller, and each of the plurality of driven rollers 13 is rotatably supported by a holder 16 that is swingably supported independently of the subframe 20. An urging member that presses the driven roller 13 against the driving roller 12 is provided between the sub-frame 2 and the sub-frame 2 . The main body frame 2 and a paper transport base 5 having a paper transport surface 4 fixed to the frame 2 to form a straight paper transport path 3 and the paper transport base 5 are exposed to the paper transport path 3 from the paper transport surface 4. A platen 6 provided opposite to the platen 6, and a pair of paper transport rollers 8 provided on the upstream side of the platen 6 in the paper transport direction and sandwiching and transporting the paper from the front and back. And a skew correction stopper 10 that is provided between the platen 6 and the pair of transport rollers 8 in the transport direction and advances into the paper transport path 3 and can be retracted from the paper transport path 3. The pair 8 is composed of a driving roller and a driven roller. The driving roller 12 is pivotally supported by the paper transport table 5, and there are a plurality of driven rollers 13. The sub-frame 20 is supported by the main body frame 2 so as to be able to swing, and the sub-frame is swung to support the follower roller. Each of the plurality of driven rollers 13 is rotatably supported by a holder 16 that is supported so as to be independently swingable to the sub-frame 20. A movable member whose position can be adjusted is provided between the holder 16 and the sub-frame 20, and an urging member that presses the driven roller 13 against the driving roller 12 is provided between the holder 16 and the movable member 21. A printing device characterized by that . The swinging shaft of the sub-frame is provided in the main body frame so that the direction in which the driven roller contacts or separates from the driving roller is a tangential direction parallel to the paper conveying direction of the driving roller. Item 4. The printing device according to Item 2 or 3. The printing apparatus according to claim 1, wherein the urging member is individually provided for each holder 16 . 6. The printing apparatus according to claim 1, wherein the urging member is a compression coil spring . The printing apparatus according to any one of claims 1 to 6, wherein the holder (16) is integrally provided with a paper guide portion for preventing the passing paper from being lifted on a side supporting the driven roller .

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