JP2971012B2 - Media transport device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medium conveying device in which a pair of conveying rollers for holding a recording medium is driven by driving force transmitting means.

[0002]

2. Description of the Related Art A medium transport apparatus for nipping and transporting a recording medium (for example, a magnetic card) on which a magnetic signal can be recorded / reproduced by a plurality of transport rollers arranged in a medium transport path has already been used in various fields. In such a medium transporting apparatus, there is a double-sided driving method in which both of the transport roller pairs are driven for the purpose of increasing the transporting force of the card. In this double-sided drive type medium transport apparatus, a plurality of drive roller pairs and a drive motor are connected by a drive force transmission mechanism. The driving force transmission mechanism includes a large pulley that transmits the rotation of the driving motor by a timing belt to rotate the driving motor, a plurality of belt pulleys that transmits the rotation of the large pulley to each transport roller, and a driving belt that is applied to each belt pulley. It is composed of The belt pulley is fixed to a drive shaft supporting each transport roller, and a drive belt is wound around the belt pulley. The large pulley is fixed to one of the drive shafts. When the large pulley rotates, the rotation is transmitted from the drive belt to the belt pulley, and each transport roller is driven to rotate.
Further, a pin clutch mechanism is provided between the drive motor and the drive force transmitting means, the pin clutch mechanism allowing the transport roller pair to rotate freely within a certain rotation range with respect to the drive motor. The pin clutch mechanism is configured such that a movable piece provided on a large pulley and a standby piece provided on a pulley on a drive shaft on which the large pulley is provided are disengaged within a certain rotation range. When the movable piece and the standby piece engage with each other, the rotation of the large pulley is transmitted to the pulley via the standby piece. In this case, the pulley on which the standby piece is formed is rotatably supported on the drive shaft.

[0003]

In the above-described medium transport apparatus of the both-side drive system, there is a pin clutch mechanism between the large pulley connected to the drive motor and the belt pulley coaxial with the large pulley, and the other belt pulley is Since the card is fixed to the drive shaft, when a card is inserted into the media transport path or is forcibly pulled out of the media transport path, the transport roller pair connected to the large pulley wraps around and the resistance at the time of pull-out or insertion is reduced. Is large. As a means for solving this problem, a pin clutch is provided between each of the conveying rollers of the conveying roller pair and the driving force transmitting means instead of providing a pin clutch between the driving motor and the driving force transmitting means. It is possible to reduce the resistance. However, providing a separate pin clutch has a new problem that it is difficult to synchronize the operation timing of the pin clutch during card transport. The purpose of the present invention is
It is an object of the present invention to provide a medium transport device that can reliably insert and pull out a recording medium into and out of a medium transport path with a small force and can easily synchronize a pair of transport rollers.

[0004]

In view of the above, according to the first aspect of the present invention, a main drive roller and a sub-drive are fixed to a first drive shaft and a second drive shaft, respectively, and are opposed to each other facing the medium transport path. A pair of transport rollers including rollers, a first rotating unit rotatably supported by the first drive shaft, a driving mechanism connected to the first rotating unit, and a first rotating unit. Engaging means comprising a movable piece provided on the first drive shaft, a standby piece provided within a movable range of the movable piece, and a first transmission means fixed to the first drive shaft. A second transmission means fixed to the second drive shaft and rotatably connected to the first transmission means. According to the second aspect of the invention, the first rotating means is constituted by a first gear, the first transmitting means is a first transmitting gear, and the second transmitting means is meshed with the first transmitting gear. It consisted of gears. According to the third aspect of the present invention, the second main drive roller and the second
And a second transport roller pair that is separately arranged from the transport roller pair, and is rotatably supported between the second secondary drive roller and the secondary drive roller. A first pulley that rotates integrally with a second gear that meshes with the first gear, a second pulley that is provided so as to rotate integrally with the second sub-drive roller, and is wound around the first pulley and the second pulley. And a speed difference absorbing means comprising a stretchable belt.

[0005]

An embodiment of the present invention will be described below with reference to the drawings. The medium conveyance device indicated by reference numeral 1 in FIG.
It is nipped and transported by the transport roller pair 6, the second transport roller pair 7, and the third transport roller pair 8, and is converted into magnetic information by magnetic heads 4 and 5 as information recording / reproducing heads arranged facing the medium transport path 2. The recording / reproducing signal is transmitted and received.

As shown in FIG. 2, the medium transport path 2 is formed between frames 1A and 1B which are arranged in parallel to face each other. At the insertion port 2 a of the medium transport path 2, card detecting means 9 and 10 are arranged to face each other via the medium transport path 2. The card detecting means 9 and 10 detect whether or not the magnetic card C is a magnetic card C based on the presence or absence of a magnetic signal of the magnetic card C to be inserted.
This is one of the triggers for opening and closing of a well-known shutter mechanism (not shown) that can be started up or moved into and out of the medium transport path 2.

[0007] First, second, and third transport roller pairs 6,
1 and 2, main driving rollers 6A, 7A and 8A arranged below the medium conveying path 2 and sub driving rollers 6B arranged above the medium conveying path 2 as shown in FIGS. 7B,
8B. Main drive roller 6
A, 7A, 8A and sub-drive rollers 6B, 7B, 8B
It is a rubber roller having a rubber layer on its outer periphery, and is a double-sided drive system that is individually driven by a drive mechanism described later. The peripheral speed of the first transport roller pair 6 and the third transport roller pair 8 is set to be lower than that of the second transport roller pair 7. Here, the peripheral speed refers to a roller surface speed or a medium conveyance speed at an outer diameter including deformation of the roller itself.

The main drive rollers 6A, 7A, 8A are provided with a pair of bearings 18a, 18b,
The first drive shaft 12 and the drive shaft 1 supported via 18c
3 and 14, respectively. First drive shaft 12,
The drive shafts 13 and 14 are provided with belt pulleys 191, 192 and 193 constituting the drive mechanism 19. As shown in FIG. 3, the belt pulleys 191 and 193 are rotatably supported on the drive shafts 12 and 14 via bearings 207A, respectively, and the belt pulley 192 is fixed to the drive shaft 13 (FIG. Only shown). Belt pulley 1
A toothed drive belt 190 is hung on 91, 192 and 193. The toothed drive belt 190 is provided with tension by the tension pulleys 21a, 21b and the tension pulley 22 which are rotatably arranged on both sides of the belt pulley 192. Measures are taken to prevent transmission loss of the driving force.

A first transmission gear 201 and a first gear 202 are fixed to the drive shafts 12 and 14 as first transmission means constituting the drive force transmission mechanism 20 to the auxiliary drive side. Sleeves 201a, 202a of first transmission gear 201 and gear 202
Are provided with pins 201b and 202b extending in the radial direction so as to pass through the drive shafts 12 and 14, respectively. The pin 202b is arranged within a rotation range of a protrusion 193a provided on the belt pulley 193 and extending in the axial direction, and can be engaged with the protrusion 193a by rotation of the pulley 193.

At the outermost end of the drive shaft 12, the drive shaft 1 is manually
A knob 39 for rotating 2 is fixed. A first gear 203 as first rotating means is rotatably supported between the first transmission gear 201 and the frame 1A via a bearing 207B. As shown in FIG. 4, the first gear 203 has an opening 203a into which a protrusion 191a projecting from the belt pulley 191 is inserted, and a pin 2 of the first transmission gear 201.
A projection 203b that can be engaged with 01b is formed. The pin 201b is arranged within the rotation range of the protrusion 203b.

That is, the first gear 203 is rotatable integrally with the belt pulley 191. When the projection 203b is engaged with the pin 201b, the first transmission gear 201 is rotated integrally with the first drive gear 201 to rotate the main drive roller. 6A is driven to rotate. The gear 202 rotates when the belt pulley 193 rotates and the projection 193a engages with the pin 202b, and rotates the main drive roller 8A. The pins 201b and 202b form a standby piece, and the projections 203b and 193a form a movable piece.
0B.

A large-diameter pulley 194 is fixed to the drive shaft 13. An endless timing belt 196 a is attached to the large-diameter pulley 194.
And a small-diameter pulley 195 fixed thereto.

As shown in FIG. 3, the auxiliary driving rollers 6B and 8B are provided with a pair of bearings 18 on the frame 1A and the frame 1C.
The sub-drive roller 7B is fixed to the drive shaft 16 supported by the pressing and moving means 3, and is fixed to the second drive shaft 15 and the drive shaft 17 supported via d and 18e, respectively.

A second transmission gear 204 and a gear 205 as second transmission means meshing with the first transmission gear 201 and the gear 202 are fixed to the second drive shaft 15 and the drive shaft 17, respectively. As shown in FIG. 4, the second drive shaft 15 includes a second gear 206 that forms a part of both the drive force transmission mechanism 20 and the speed difference absorbing unit 23 between the second transmission gear 204 and the frame 1 </ b> A. A gear pulley 231 as a first pulley having a rotation shaft is rotatably supported via bearings 208A and 208B. The second gear 206 meshes with the first gear 203 on the main drive side.

A second pulley 233 is fixed to the drive shaft 16. The second pulley 233 and the toothed pulley 231
Are formed with two circumferential grooves 231a and 233a, respectively, and two round belts 232 are wound around each groove. The round belt 232 has elasticity,
When a rotation difference between the main drive roller 7A and the sub drive roller 7B occurs, the round belt 232 is
Is set so that it expands and contracts. That is, the driving force transmitted to the sub main driving roller 7B by the driving force transmission mechanism 20 is buffered, and the main driving roller 7
A follows. Here, the round belt 232 is used, but the present invention is not limited to this. For example, an elastic flat belt may be used. In this case, there is no need to provide a circumferential groove as in the case where the round belt 232 is used for the pulley around which the flat belt is wound.

Next, the pressing and moving means 3 will be described.
The pressing and moving means 3 connects the sub drive roller 7B to the main drive roller 7B.
A, which movably supports and presses against A, includes a pad arm 30 for supporting the drive shaft 16 and a compression coil spring 32, as shown in FIGS. The pad arm 30 has a U-shaped cross section and extends in the card transport direction (the direction of arrow A). The base end 301 of the pad arm 30 is disposed on the card insertion slot 2a side, and is swingably supported by the shafts 31 on the frames 1A and 1C. The drive shaft 16 is rotatably supported at the free end 302 of the pad arm 30 via bearings 37 and 38 on the side surfaces 30a and 30b. Drive shaft 1
Numeral 6 protrudes out of the medium transport path 2 from an opening 1E provided in the frame 1A, which is larger than the coaxial diameter, and has a structure for preventing interference with the frame 1A during movement.

On the pad arm 30 located above the drive shaft 16, an arm guide shaft 33 is arranged to penetrate upward through a spacer 36. As shown in FIG. 6, a threaded portion 33a is formed on the upper end side of the arm guide shaft 33. The threaded portion 33a is screwed to a pad frame 1D on which the frame 1A is formed. A free end 302 side of 30 is supported so as to be movable. A lock nut 35 for preventing loosening is screwed into the screw portion 33a from above the pad frame 1D.

A compression coil spring 32 is provided between the lower surface 1Da of the pad frame 1D and the upper surface 30c of the pad arm 30.
Are arranged so as to surround the arm guide shaft 33, and urge the drive shaft 16 downward to generate a pressing force on the magnetic card C. A groove 33b is formed at the end of the arm guide shaft 33. As shown in FIG. 5, a tool 40 is inserted into the groove 33b and rotated, so that the main drive roller 7A and the sub drive roller 7B are rotated. Adjustment of the interval with

The magnetic card C and the magnetic heads 4 and 5 will be described. FIG. 7A shows a card C according to the present embodiment.
A thick card C1 represented by a credit card or the like in which a magnetic stripe C1a shown in FIG.
And a thin card C2 represented by a prepaid card or the like in which a magnetic stripe C2a shown in FIG. 7B is provided on the lower surface of the card. The magnetic head 4 corresponds to the thick card C1, and the magnetic head 5 corresponds to both the thick card C1 and the thin card C2. The magnetic head 4 contacts the magnetic stripes C1a and C2a of the cards C1 and C2, respectively. Send and receive. The magnetic head 4 is urged toward the magnetic head 5 by pressing means (not shown).
Further, the magnetic heads 4 and 5 are arranged near the second pair of transport rollers 7 so as to be shifted in the axial direction. That is, the first and third transport roller pairs 6 and 8 are disposed before and after the magnetic heads 4 and 5 in the transport direction.

The medium transport path 2A near the second transport roller pair 7
Has a narrow width in the card thickness direction as shown in FIG. This width is set slightly larger than the thickness of the thick card C1, and is designed so that the card C can contact the magnetic heads 4 and 5 as perpendicularly as possible. The first drive shaft 12, the second drive shaft 15, and the drive shaft 14 contact the drive shaft 17 to such an extent that the peripheral surfaces of the main drive roller 6A and the sub-drive roller 6B and the main drive roller 8A and the sub-drive roller 8B do not deform. It is between fixed axes.

The operation of the medium transport device 1 having such a configuration will be described. When the magnetic card C is inserted into the card insertion slot 2a and a magnetic signal is detected by the card detection means 9 or 10, the drive motor 11 is started and the magnetic card C is transported in the card transport direction A here. At 1, the shutter is rotated clockwise, and at the same time, a shutter member (not shown) is retracted from the medium transport path 2. The rotation of the drive motor 11 is controlled by the large-diameter pulley 19 via a timing belt 196.
4, the drive shaft 13 rotates and the main drive roller 7A
Is driven to rotate.

The rotation of the drive shaft 13 is transmitted to belt pulleys 191 and 193 via a toothed belt 190. When the belt pulley 191 rotates, as shown in FIG. 4, it is transmitted from the second pulley 233 shown in FIG. 3 to the drive shaft 16 via the integrated first gear 203, second gear 206 and round belt 232, and 7B is driven to rotate. First gear 20
3 rotates and the projection 203b engages with the pin 201b, the first transmission gear 201 rotates to rotate the first drive shaft 12, and the first transmission gear 201, the second transmission gear 20
4 rotates the second drive shaft 15 via the main drive roller 6A.
And the auxiliary drive roller 6B is rotationally driven.

The belt pulley 193 rotates and the protrusion 193
When a is engaged with the pin 202b, the gear 202 rotates and the first drive shaft 12 rotates, and the drive shaft 17 rotates via the gear 202 and the gear 205 to rotate the main drive roller 8A.
And the auxiliary drive roller 8B are driven to rotate, and the first, second, third
The transport roller pairs 6, 7, 8 are driven.

The inserted magnetic card C includes first, second,
The third pair of conveying rollers 6, 7, 8 are sandwiched in this order and conveyed in the medium conveying path 2, and the card type (C
1, C2), one of the magnetic heads 4 and 5 transmits and receives a magnetic recording signal.

At this time, for example, as shown in FIG. 9, the magnetic card C is jammed in the medium transport path 2 while being pinched by the transport roller pair 6 due to the deformation (curvature) of the card. Assume that the knob 39 shown is rotated. Then
The first transmission gear 201 fixed to the first drive shaft 12 rotates, and the second transmission gear 204 shown in FIG. 3 in mesh with the first transmission gear 201 rotates.
Is fixed, the second drive shaft 15 rotates. First gear 20
3 and the second gear 206 are in mesh with each other, but the first drive shaft 1
2 and the second drive shaft 15 are rotatably supported. The pin 201b provided on the first drive shaft 12 is
The main drive roller 6A and the sub drive roller 6B rotate until they engage with the protrusion 203b provided on the gear 203, but this rotation is not transmitted to the pulley 191 and the toothed pulley 231. Therefore, since the rotation of the knob 39 is not transmitted to the pulley 191 and the toothed belt 190 constituting the driving mechanism 19, the driving force connection between the first transport roller 6 and the driving mechanism 19 is released, and the weight is light. The knob 39 can be turned by force, and the clogged magnetic card C can be easily collected.

In the conventional medium transport device, a large pulley 194 is used.
And the pulley 192 are provided with the engagement means 200A here, so that when the knob 39 is turned as in this embodiment, all of the first to third transport roller pairs 6, 7, 8 rotate. As a result, a large force is required to rotate the knob 39, but this embodiment can solve such a problem.

On the other hand, if the load from the magnetic card C to be conveyed is applied to the sub-conveying roller 7B more than the main driving roller 7A, for example, the peripheral speed of the sub-driving roller 7B may be reduced due to abrasion or the like. When it becomes faster than the peripheral speed of 7A,
As shown in FIG. 8, the round belt 232 transmitting the driving force to the sub-transport roller 7B expands and contracts with respect to the pulleys 231 and 233, the driving force applied to the sub-transport roller 7B is reduced, and the peripheral speed difference is absorbed. You. On the other hand, since the driving force is transmitted to the main driving roller 7A by the toothed driving belt 190, the round belt 2
It is less likely to slip than 32. That is, the driving force for the main driving roller 7A is larger than the driving force for the sub driving roller 7B. Therefore, the card C held between the second conveying roller pair 7 is moved to the main driving roller 7 having a large driving force.
A is conveyed under the control of the main driving roller 7
The magnetic card C can be stably conveyed even when a peripheral speed difference occurs between A and the sub-drive roller 7B, and recording and reproduction of the magnetic card C can be performed stably.

The first transport roller pair 6 and the third transport roller pair 8 whose peripheral speeds are set lower than the second transport roller pair 7 include:
Since the engagement means 200A and 200B are provided, when the magnetic card C is transported from the first transport roller pair 6 or the third transport roller 8 toward the second transport roller 7 and enters the second transport roller, A driving force is applied to the card C from above and below by a main driving roller 7A and a sub driving roller 7B that are driven. Then, the main and sub drive rollers 6A and 6B of the first conveyance roller pair and the main and sub drive rollers 8A and 8B of the third conveyance roller pair are connected to the first drive shaft 12, the second drive shaft 15 and the drive shafts 14 and 17, respectively. The projection 203b and the pin 201b and the projection 193a and the pin 20
2b is momentarily released. That is, the first transport roller pair 6 and the third transport roller pair 8 idle with respect to the drive mechanism 19 and the drive force transmission mechanism 20.

Therefore, the first conveying roller pair 6 or the third conveying roller pair 6
The transport roller pair 8 is driven by the second transport roller pair 7, and only the driving force of the second transport roller pair 7 is transmitted to the card C. Therefore, the magnetic card C has the magnetic heads 4, 5
When being transported in the vicinity, the card is transported at a transport speed corresponding to the peripheral speed of the second transport roller 7 without being interfered by the transport force of the first transport roller pair 6 and the third transport roller pair 8. Speed fluctuations are reduced, the transport speed is stabilized, and recording / reproducing defects are reduced.

Even if the roller diameter of each of the transport roller pairs 6, 7, 8 changes due to the influence of temperature or the like, the peripheral speed of the second drive roller pair 7 does not steadily increase and the other transport roller pairs 7 Set so that the peripheral speed is faster than 6, 8
And engaging means 200A, 20 with third conveying roller pairs 6, 8
By providing 0B, the gap between each transport roller pair 6, 7, 8 can be made zero. Therefore, even if the thickness of the transported card C is different, each transport roller pair 6, 7, 8,
Of the magnetic heads 4 and 5, the engaging means 200A, 2
Due to the action of 00B, the recording medium can be transported at a transport speed corresponding to the peripheral speed of the second transport roller 7 without being affected by the transport speeds of the first and third transport roller pairs 6, 8, and the recording and reproduction by the magnetic heads 4, 5 It can be performed stably.

In order to make the peripheral speed of the second conveying roller pair 7 faster than that of the other conveying roller pairs 6 and 8, the diameter of the main drive rollers 6A and 8A is made smaller than that of the main drive roller 7A. Setting, changing the gear ratio of the driving means 19 and the driving force transmitting means 20 to the first conveying roller pair 6 and the third conveying roller pair 8, or the roller diameter of each conveying roller pair 6, 7, 8 And the first and third pairs of transport rollers 6, 8 and the second pair of transport rollers 7 are driven by a drive mechanism having individual drive motors having different rotation speeds.

In the embodiment, the main driving rollers 6A, 7A, 8
A is a sub-drive roller 6B, 7B,
8B has been described as an example disposed below the medium transport path 2,
The main and sub drive rollers may be arranged upside down.
In short, the present invention can be applied to any pair of double-sided drive type conveyance rollers that hold the magnetic card C from both sides and apply a driving force.

The medium transport device 1 in the embodiment is of the forward transport type (in the direction of arrow A), but may be applied to a medium transport device of a type in which the magnetic card C is transported back and forth to return to the card insertion slot 2a. Absent.

Although the recording medium of the present invention has been described with reference to the magnetic card C in the embodiment, the recording medium is not limited to the magnetic card, but may be a magnetic IC card having an IC chip mounted on the magnetic card. Of course it doesn't matter. In general, a magnetic IC card has a higher rigidity and is less likely to be deformed than a simple magnetic card C. Therefore, when the magnetic IC card is jammed in the medium transport path 2, the magnetic IC card is more strongly sandwiched by the transport roller pairs 6, 7, 8 than the magnetic card. However, card collection requires more power than magnetic cards. Therefore, providing the above-described pin clutch mechanisms 200A, 200B on the transport roller pairs 6, 8 is
The present invention is also effective for a medium transport device that transports a card that is difficult to deform or that should not be deformed.

[0035]

According to the first aspect of the present invention, the movable piece provided on the first rotating means rotatably supported by the first drive shaft does not engage with the standby piece provided on the first drive shaft. And the transport roller pair is in a free state with respect to the drive mechanism, so that the recording medium can be reliably inserted and withdrawn from the medium transport path with a small force even in a double-sided drive type media transport device. . In addition, when the movable piece and the standby piece engage, the driving force from the drive mechanism is fixed to the first drive shaft fixed to the first drive shaft.
The power is transmitted to the second transmission means fixed to the second drive shaft via the transmission means, and the main drive roller and the sub drive roller fixed to each drive shaft are driven synchronously. Therefore, the first and second
With a simple configuration in which the transmission means is provided, the synchronization of the transport rollers can be easily performed.

According to the second aspect of the present invention, the first rotating means comprises a first gear, the first transmitting means comprises a first transmitting gear, and the second transmitting means comprises a first transmitting gear. Since it is constituted by the meshing second transmission gear, in addition to the effect of the invention of the first aspect, the driving force from the driving mechanism can be transmitted to the transport roller pair without loss.

According to the third aspect of the present invention, the rotational driving force from the drive mechanism is transmitted to the second sub-drive roller pair constituting the second drive roller pair via the elastic belt. In addition to the effect of the second aspect, when a peripheral speed difference occurs between the second drive roller and the second sub-drive roller of the second transport roller pair, the rotational driving force to the second sub-drive roller becomes elastic. The belt expands and contracts, and the peripheral speed difference of the second sub-drive roller with respect to the second drive roller can be absorbed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a medium conveyance device according to an embodiment of the present invention.

FIG. 2 is a plan view showing a configuration of a main driving roller and a driving unit thereof.

FIG. 3 is a plan view showing a schematic configuration of a sub-drive roller and its driving force transmission means, and a pressing movement means and a speed difference absorption means.

FIG. 4 is a partially cutaway front view showing a configuration and a structure of an engaging means which is a main part of the present invention.

FIG. 5 is a side view showing the configuration of the pressing and moving means.

FIG. 6 is a partially cutaway front view showing the configuration of the pressing and moving means.

FIG. 7 is a plan view of a recording medium applied to the present invention.

FIG. 8 is an enlarged view showing the operation of the speed difference absorbing means.

FIG. 9 is a side view illustrating a state where a recording medium is jammed in a first conveying roller pair.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 medium conveyance device 2 medium conveyance path 6 conveyance roller pair 6A main drive roller 6B sub-drive roller 7 second conveyance roller pair 7A second main drive roller 7B second sub-drive roller 12 first drive shaft 15 second drive shaft 19 drive Mechanism 20 Speed difference absorbing means 201 First transmitting means (first transmitting gear) 200A Engaging means 201b Standby piece 203 First rotating means (first gear) 203b Movable piece 204 Second transmitting means (second transmitting gear) 206 2 rotation means (second gear) 231 first pulley 232 elastic belt 233 second pulley

Claims (3)

(57) [Claims] A transport roller pair fixed to a first drive shaft and a second drive shaft, the transport roller pair including a main drive roller and a sub drive roller facing each other facing a medium transport path; A first rotating unit rotatably supported on the driving shaft, a driving mechanism connected to the first rotating unit, a movable piece provided on the first rotating unit, and a movable member provided on the first driving shaft. Engaging means comprising a standby piece disposed within a movable range of the movable piece; first transmitting means fixed to the first drive shaft; and first transmitting means fixed to the second drive shaft. A medium transport device comprising: a second transmission means rotatably coupled to the means. 2. The first rotating means comprises a first gear, the first transmitting means comprises a first transmitting gear, and the second transmitting means comprises a second transmitting gear meshing with the first transmitting gear. The medium transport device according to claim 1, wherein A second main driving roller and a second sub driving roller, wherein the second main driving roller and the second sub driving roller are arranged separately from the transport roller pair.
A first pulley having a pair of conveying rollers, a first pulley rotatably supported between the second sub-drive roller and the sub-drive roller, and integrally rotating with a second gear meshing with the first gear; (2) that a speed difference absorbing means composed of a second pulley provided so as to be able to rotate integrally with the sub-drive roller and an elastic belt wound around the first pulley and the second pulley is interposed. 3. The medium transport device according to claim 2, wherein: