JP3197088B2 - Sheet transport device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a device for transporting sheets (recording paper, manuscript paper) such as a printer, a typewriter, a copying machine, and a facsimile to a recording unit or a reading unit. The present invention relates to a device which is fed with high precision without skew in the direction perpendicular to the bus.

[0002]

2. Description of the Related Art As shown in FIG. 11, in a recording apparatus 150 such as a conventional typewriter, when a sheet P is set in the apparatus, the sheet P is placed on a sheet feeding tray 151 provided at an angle, and a platen knob 152 is set. When the sheet P is once wound around the platen 153 and then the platen knob 152 is reversed, the sheet P is disengaged from the meshing portion between the platen 153 and the pinch roller 155. It stays along the meshing portion with the pinch roller 155. Next, when the platen knob 152 is rotated forward, the sheet P is placed on the platen 153.
Is reliably transported in a direction perpendicular to the generatrix. The above method is a method that has been often used conventionally.

[0003] In Japanese Patent Publication No. 62-3826, as shown in FIG.
61 until the sheet P fed to the drive roller 162 passes through the engagement portion of the drive roller.
And the sheet P is bent between the pickup roller 161 and the drive roller 162 so that
The leading end of the sheet P is brought into contact with the meshing portion of the drive roller 162 with the leading end of the sheet P.
A method of feeding the sheet P by rotating the sheet 62 forward is proposed.

[0004]

However, FIG.
In the conventional example, when the sheet P stays at the meshing portion between the platen 153 and the pinch roller 155 and then re-enters the meshing portion of the platen 153 by rotating the knob 152, the leading end of the sheet P meshes with the platen 153. Since the force for pressing the sheet P must depend on the weight of the sheet P, when the sheet feeding direction is close to horizontal, the force for pressing the sheet P against the engagement portion of the platen 153 does not work, and the sheet P cannot re-enter. There was a major drawback.

[0005] In the conventional example of FIG.
The force for pressing the leading end of the sheet against the meshing portion 2 utilizes the repulsive force of the sheet P by bending the sheet P, so that the sheet feeding direction is not limited, but it is assumed that the sheet P is bent. Therefore, there is a drawback that a sheet P to be used which is thick and hard to be bent cannot be used.
The space and the length of the passage for bending the sheet P must be sufficiently provided, and it is difficult to reduce the size of the apparatus.

The present invention provides a sheet conveying apparatus capable of accurately feeding a sheet in a sheet feeding direction even when a sheet is inserted obliquely and a thick sheet is fed. The purpose is to provide.

[0007]

According to one aspect of the present invention, there is provided a main roller configured to be rotatable in a sheet conveying direction and in a direction opposite to the sheet conveying direction. Pressing means for forming a holding portion so as to hold the conveyed sheet, and an auxiliary roller disposed upstream of the main roller in the sheet conveying direction, wherein the auxiliary roller conveys the sheet by the main roller When rotating in the direction and conveying the sheet, it rotates in the sheet conveying direction, and when the sheet is conveyed in the opposite direction to the sheet conveying direction, by rotating or moving by the sheet conveyed in the reverse direction, The main roller is configured to accumulate a conveying force in a sheet conveying direction with respect to the sheet, and after the main roller nips the sheet with the holding portion formed by the main roller and the pressing unit, the main roller When the sheet is conveyed so as to be reversed by a predetermined amount to cause the sheet to come out of the holding section, the auxiliary roller receives a force from the sheet conveyed in the reverse direction and accumulates a conveying force in the sheet conveying direction, and When a sheet comes out of the sheet, the leading end of the sheet is made to follow the holding portion by the stored conveying force.

[0008]

According to the present invention, when the sheet is conveyed in the reverse direction of the sheet conveyance direction by the reverse rotation of the main roller, the auxiliary roller is rotated or moved in the direction opposite to the sheet conveyance direction, and the rotation or movement causes the auxiliary roller to move in the forward direction. To store the transfer force of Then, when the sheet passes through the holding portion, the stored conveying force is applied to the sheet, and the leading end of the sheet stays along the holding portion. This operation corrects skew.

[0009]

1 and 2 show a first embodiment of the present invention. FIG. 1 is a sectional view of the apparatus, and FIG. 2 is a schematic view showing a sheet conveying mechanism of the apparatus.

In FIG. 1, the outside of the apparatus main body 1 is composed of a cover 2 and a paper feed table 3, and the cover 2 is provided with a paper feed port 2a and a paper discharge port 2b, and the feed table 3 is provided with a paper guide 3a. ing. The sheet P is inserted from the paper feed port 2a and discharged from the paper discharge port 2b.

Inside a plurality of side plates 4 provided in the apparatus 1, a main roller 5 for conveying a sheet, a support shaft 6 to which the main roller 5 is fixed, and a guide plate 7 for guiding the sheet are provided. The sensor S1 provided in the hole of the guide plate 7
And a platen 8 for holding a print position of the sheet, and a fulcrum 9
a pressing plate 9 to which a rotational force is applied in the direction of the main roller 5 by a spring 10 around a, and a pressing roller 11 attached to a free end of the pressing plate 9 and bringing the sheet into contact with the main roller 5 A carriage 13 guided by a plurality of guide shafts 12 and movable in the sheet width direction; and a recording head 14 mounted on the carriage 13 and performing printing in accordance with image information.

The means for bringing the sheet into contact with the main roller 5 may be a part of the holding plate 9 other than the structure of the holding plate 9 and the holding roller 11 provided at its free end. Alternatively, a thin plate having a spring property, such as stainless steel, may be used for the holding plate without the holding roller.

Further, a spindle 15, a ring 16 fixed to the spindle 15, and the ring 16
Pins 16a and 16b planted on the peripheral surface of the auxiliary shaft 17, an auxiliary roller 17 having a pin 17a disposed on the side and rotatably mounted on the support shaft 15, a pin 16a and a pin 17a
, A pinch roller 20 which is pressed against the auxiliary roller 17 while being supported by a spring plate 19, and a sensor S2 disposed near the paper feed port 2a. ing. The surface of the auxiliary roller 17 is made of a material having high friction characteristics such as rubber.

In FIG. 2, a motor M1 is a motor gear 2
The main roller 5 is rotated based on a control signal from a controller 24 as a control device via a first and second gear 22 and a main roller gear 23 fixed to the shaft 6.

The rotation of the motor M1 is controlled by the main roller gear 23.
The gears 25 and 26 are connected to the shaft 15 via a one-way clutch 28.

The one-way clutch 28 is connected to the main roller 5.
The rotation of the gear 27 in the direction of the arrow 30 in conjunction with the rotation of the sheet P in the forward direction 29 is transmitted to the shaft 15 in the forward direction of the sheet P. The rotation of the gear 27 in the direction of the arrow 32 interlocked with the rotation of the gear 27 is not transmitted to the shaft 15.

A ratchet lever 34, which is counter-clockwise rotated by a biasing force of a spring 35 around a shaft 34a, on the outer periphery of a ratchet wheel 33 fixed to the support shaft 15 and having a sawtooth on the outer periphery. The tip is in contact.
The ratchet lever 34 is connected to the ratchet wheel 3.
3 is allowed to rotate in the direction of arrow 30, but is prevented from rotating in the direction of arrow 32.

The plunger 36 is connected to the controller 24.
By moving the movable rod 37 upward based on the control signal, the ratchet lever 34 in contact with the bent portion at the lower end of the movable rod 37 is rotated clockwise around the shaft 34d against the force of the spring 35. The ratchet wheel 3
The ratchet wheel 33 can be rotated clockwise by releasing the engagement with the third tooth portion.

<Operation of First Embodiment> Next, a sheet conveying operation in the apparatus of the first embodiment will be described with reference to FIGS. When the sheet P is inserted from the paper feed port 2a along the paper feed table 3 and the paper guide 3a, the sensor S2 detects the leading edge of the sheet. Based on the detection, the controller 24 activates the motor M1 to rotate the main roller 5 in the direction of the arrow 29 which is the sheet normal feeding direction.

The rotation of the main roller 5 is performed by the gear 23 and the gear 2.
5. The rotation is transmitted to the gear 27 through the gear 26 in the direction of the arrow 30.

When the gear 27 rotates in the direction of arrow 30, the one-way clutch 28 connects the gear 27 and the support shaft 15, so that the support shaft 15 also rotates in the same direction. The rotation of the support shaft 15 includes a ring 16 fixed to the support shaft 15, a pin 16a provided on the peripheral surface of the ring 16, a pin 17a provided on a side surface of the auxiliary roller 17, and 16
The auxiliary roller 17 is transmitted to the auxiliary roller 17 via a spring 18 connected to the auxiliary rollers 17a and 17a, and also rotates in the direction of the arrow 30.

The pin 17a is always in contact with the pin 16b by the spring 18 with a predetermined force during the rotation. By the rotation of the auxiliary roller in the direction of the arrow 30, the sheet P is conveyed to the back of the apparatus, and the leading end of the sheet is
Is detected, the controller 24 controls the motor M1 to feed the front end of the sheet by the length L shown in FIG. The protruding length N from the contact position between the main roller 5 and the pressing roller 11 to the leading edge of the sheet will be described with reference to FIG.

FIG. 9 is a schematic view of the sheet conveying section of the apparatus 1 in FIG. 1 as viewed from above.

The projecting length N in a state where the sheet P is conveyed obliquely as P ₁ is protruding length T of the left depends on the left and right, the right projection length U next, T-U = W becomes a difference exits.

Assuming that the difference W is the skew amount, when the amount of W is large, the amount of the protruding length N needs to be increased accordingly. However, the amount is limited by the size of the paper feed port 2a or the like. It is necessary to provide.

The sheet side edge regulating means 3a, 3a are effective means for regulating the amount of W. Assuming that the maximum skew amount W is 3 mm and a margin such as a slip between the sheet P and each conveying roller is 2 mm, the projection length N is N = 3 + 2 = 5.

The main roller 5 rotates under the control of the controller 24 in the direction indicated by the arrow in the sheet feeding direction from the state in which the sheet leading end is protruded by N.

It is desirable that the amount of rotation of the main roller 5 is at least as long as the protrusion length N, for example, equivalent to a transport length of about 2 × N to 3 × N.

The gear 27 rotates in the direction of the arrow 32 in conjunction with the rotation of the main roller 5 in the direction of the arrow 31, but this rotation is not transmitted to the support shaft 15 by the action of the one-way clutch 32.

The auxiliary roller 17 rotates in the direction of the arrow 32 following the reverse movement of the sheet P. On the other hand, pin 17
a also rotates, but the support shaft 15 is
3. The arrow 32 is actuated by the action of the ratchet lever 34.
Since the rotation in the direction is prevented, the pin 16a does not rotate, and the rotation of the auxiliary roller 17 is performed with the spring 18 extended. Since the tension force of the spring 18 acts to rotate the auxiliary roller 17 in the direction of the arrow 30, the auxiliary roller 17 constantly applies a conveying force in the normal feeding direction to the sheet during this time. In addition, since the plurality of auxiliary rollers 17 are independently rotatably fitted to the support shaft 15, even if the amount of movement of the sheet in the reverse feeding direction is different at a position within the sheet, each of the auxiliary rollers 17 is different. It responds independently.

[0031] In FIG. 9, the sheet P is Once backhaul from the state of P _1, firstly is the right end projection length U is sent to the contact position, when exiting the contact position of the main roller 5 and the pressing roller 11 it The above does not retreat. While left is backhaul sent to said contact position behind the right end so U <T, the left and right front end of the sheet P is in a state of P ₂ staying along the contact position at the same time. The biasing force of the spring 18 so that the sheet tip is not bent in the state of the P ₂ is set. The state of the P ₂ as the start position of the sheet search, the controller 24 left and right leading end of the sheet P main roller 5 and a predetermined amount rotated in the arrow 29 direction by transition power of the positive feeding direction of the auxiliary roller 17 is the The sheet passes through the contact position along the contact position, and is conveyed to the print recording position of the recording head 14 with high accuracy without skew.

Next, based on the print signal, the sheet P is successively fed by a predetermined amount in the normal feeding direction, the carriage 13 reciprocates in the sheet width direction, and printing is performed by the recording head 14. When printing is performed again in a special printing mode during printing, for example, returning to the preceding printing area, the controller 24 enables the ratchet wheel 33 to rotate in the direction of the arrow 32 by operating the plunger 36. At the same time, in order to return the sheet P to the preceding printing position, when the main roller 5 is rotated in the direction of the arrow 31 by a predetermined amount, the auxiliary roller 17 follows the reverse feeding movement of the sheet P without generating a transition force in the normal feeding direction. The sheet P is conveyed with the conveyance accuracy of the main roller 5. Thereafter, when the main roller 5 rotates in the forward direction, the controller 24 stops the operation of the plunger 36 and returns to the original state.

As another method of controlling the plunger 36, when the sheet P comes to the printing position of the recording head 14, the plunger 36 is driven to lift the lever 34, and the operation of the plunger 36 is stopped by the operation described above. There is also a method of performing the operation when the recording operation of the sheet P is completed.

When the sensor S1 detects the rear end of the sheet P, the main roller 5 feeds a predetermined amount of sheet for printing under the control of the controller 24.

After the completion of the last sheet feeding, the main roller 5 performs a predetermined amount of sheet discharging rotation to rotate the discharging port 2.
The sheet is discharged from b.

The controller 24 rotates the main roller 5 when the total sheet feed amount for printing stored in advance has been reached according to an instruction from the computer, without the signal for detecting the trailing edge of the sheet by the sensor S1. Then, the sheet is discharged.

The controller 24 sets the apparatus 1 to the initial state when the signal of the sensor S1 is a signal indicating that there is no paper after the sheet discharging operation by the main roller 5. On the other hand, when the signal is a signal indicating that there is paper, it is determined that a sheet conveyance failure has occurred, and a warning is issued by a display unit, an acoustic unit, or the like.

A second embodiment will be described with reference to FIGS.

FIG. 3 is a sectional view of the present apparatus, and FIG. 4 is a schematic view showing a sheet conveying mechanism of the present apparatus. 3 and 4, members having the same shape and function as those shown in FIGS. 1 and 2 are denoted by the same reference numerals.

In FIG. 3, the outside of the apparatus main body 1 is composed of a cover 2 and a paper feed table 3.
A paper guide 3 a is provided on the paper feed table 3. The sheet P is inserted from the paper feed port 2a and discharged from the paper discharge port 2b. Inside the plurality of side plates 40,
A main roller 5 for conveying the sheet P, a support shaft 6 to which the main roller 5 is fixed, and a guide plate 7 for guiding the sheet
A sensor S1 provided in a hole of the guide plate 7, a platen 8 for holding a printing position of a sheet, and a presser to which a rotating force is applied in the direction of the main roller 5 by a spring 10 about a fulcrum 9a. A holding plate 9, a holding roller 11 mounted on a free end of the holding plate 9 to contact the sheet with the main roller 5, and a carriage 13 guided by a plurality of guide shafts 12 and movable in the width direction of the sheet. And this carriage 1
3 is provided with a recording head 14 for performing printing in accordance with print information.

Further, the support shaft 41 is formed in the apparatus main body 1 by a long hole 40a provided in the side plate 40, and the support shaft 41 is indicated by a dotted line.
As shown in FIG. A support shaft 41, an auxiliary roller 42 fixed to the support shaft and having a surface made of a material having high friction such as rubber, and a predetermined force applied to the auxiliary roller 42 by the urging force of a spring 44 about the support shaft 43a. A guide plate 43 which is in contact with the pressure and whose contact surface is made of a slippery material, and a sensor S2 is provided in a hole of the guide plate 43 near the insertion opening 2a.

In FIG. 4, a motor M1 is a motor gear 2
The main roller 5 is rotated based on a control signal from a controller 24 via a first and second gear 22 and a main roller gear 23 fixed to the shaft 6.

The rotation of the motor M1 is controlled by the main roller gear 2
The gears 25 and 26 are connected to the shaft 45 via the one-way clutch 28.

The one-way clutch 28 transmits the rotation of the gear 27 in the direction of the arrow 30 to the shaft 45 but does not transmit the rotation of the gear 27 in the direction of the arrow 32.

The shaft 45 and the support shaft 41 are connected via a universal joint 46 that bends and transmits rotation.

A plurality of free rollers 47 are rotatably fitted on the support shaft 41.

A spring 48 whose end is connected to one end 41a of the support shaft 41 and a spring hooking portion 40b provided on the side plate 40, connects the support shaft 41 along the elongated hole 40a to the main shaft. The movement in the direction close to the roller 5 is urged.

The tip of a ratchet lever 34, which is counterclockwise rotated by the urging force of a spring 35 around a shaft 34a, is attached to the outer periphery of a ratchet wheel 33 fixed to a shaft 45 and having a sawtooth on the outer periphery. Abut. The ratchet lever 34 allows the ratchet wheel 33 to rotate in the direction of the arrow 30 but prevents the ratchet wheel 33 from rotating in the direction of the arrow 32.

The plunger 36 is connected to the controller 24
The movable bar 37 is moved upward based on the control signal. The ratchet lever 34, which comes into contact with the bent portion provided at the lower end of the movable rod 37 by the movement, is rotated clockwise about the shaft 34a, and escapes from the meshing portion of the ratchet wheel 33. Rotation in 32 directions becomes possible.

<Operation of Second Embodiment> Next, a sheet conveying operation of the second embodiment will be described with reference to FIGS. The sheet P is fed to the feeding table 3 and the paper guide 3a.
, The sensor S2 detects the leading edge of the sheet, whereby the controller 24 activates the motor M1 to rotate the main roller 5 in the direction of arrow 29.

The rotation of the main roller 5 is performed by the gear 23 and the gear 2.
5. The gear 27 is rotated in the direction of the arrow 30 through the gear 26.

When the gear 27 rotates in the direction of the arrow 30, the one-way clutch 28 connects the gear 27 and the shaft 45, so that the support shaft 41 also rotates in the direction of the arrow 30 via the universal joint 46. The sheet P sandwiched between the auxiliary roller 42 fixed to the support shaft 41 and the guide plate 43 is sent to the main roller 5 by the rotation of the auxiliary roller 42. The free roller 47 is guided by the movement of the sheet P, and guides the sheet P while suppressing the floating of the sheet P.
When the sensor S1 detects the leading end of the sheet P, the controller 24 controls the motor M1 to feed the sheet P by the length L.

Next, the controller 24 rotates the main roller 5 by a predetermined amount in the direction of the arrow 31 to rotate the sheet P.
The auxiliary roller 42 tries to rotate in the direction of the arrow 32 with the movement of the ratchet lever 34 in the reverse direction.
Rotation of the auxiliary roller 4
2 moves away from the roller 5 while tensioning the spring 48 while the rotation is stopped. The auxiliary roller 42
Keeps applying a moving force in the normal feeding direction to the sheet P by the tension during the movement operation.

During the reverse rotation of the main roller 5, when the left and right ends of the sheet P move back and forth and come out of the contact position between the main roller 5 and the pressing roller 11, the left and right ends of the sheet P are stored in the auxiliary roller 42. It stays along the contact position due to the applied conveying force. The urging force of the spring 48 is set so that the leading end of the sheet is not bent by the conveying force.

After the main roller 5 has been rotated in the forward direction by a predetermined amount after the main roller 5 has been rotated in the reverse direction by a predetermined amount and the above state is set as the start position of the sheet cueing, the left and right ends of the sheet P Due to the transfer force, the sheet passes through the contact position along the contact position, and is further fed to the print recording position of the recording head 14 without skew and with high precision.
Thereafter, the operation from the completion of printing to the subsequent discharge of the sheet is the same as in the first embodiment, and a description thereof will be omitted.

A third embodiment (reference example) will be described with reference to FIGS.

FIG. 5 is a sectional view of the present apparatus, and FIG. 6 is a schematic view showing a sheet conveying mechanism of the present apparatus. In FIGS. 5 and 6, members having the same shape and function as those shown in FIGS. 1 and 2 are denoted by the same reference numerals.

In FIG. 5, the outside of the apparatus main body 1 is composed of a cover 2 and a paper feed table 3. The cover 2 is provided with a paper feed port 2 a and a paper discharge port 2 b, and the paper feed table 3 is provided with a paper guide 3 a. ing. The sheet P is inserted from the paper feed 2a and discharged from the paper discharge port 2b. Inside the plurality of side plates 50, a main roller 5 for discharging the sheet, a support shaft 6 to which the main roller 5 is fixed, and a guide member 51 for guiding the sheet.
And a sensor S1 provided in a hole of the guide plate 51;
A platen 8 for holding a printing position of a sheet, a pressing plate 9 to which a rotating force is applied in the direction of the main roller 5 by a spring 10 about a fulcrum 9a, and a sheet mounted on a free end of the pressing plate 9 And a carriage 13 guided by a plurality of guide shafts 12 so as to be movable in the width direction of the sheet, and mounted on the carriage 13 for printing corresponding to image information. Is provided.

Further, in the apparatus main body 1, there is provided a lever 54 to which a counterclockwise rotation is given by a biasing force of a spring 53 about a pin 52, and one end of the lever 54 is rotatably supported by a shaft. A shaft 55, an auxiliary roller 56 fixed to the shaft 55, a shaft 57 whose end is supported by the side plate 50, an auxiliary roller 58 fixed to the shaft 57, A sensor S2 is provided near the insertion slot 2a.

In FIG. 6, a motor M1 rotates a main roller 5 based on a control signal from a controller 24 via a motor gear 21, a two-stage gear 22, and a main roller gear 23 fixed to the shaft 6.

The rotation of the motor M1 is controlled by the main roller gear 2
The gear 60 and the gear 6 via the gear 59 meshing with the gear 3
It is conveyed to 1.

The one-way clutch 62 transmits the rotation of the gear 60 in the direction of the arrow 63 to the shaft 55 but does not transmit the rotation in the opposite direction.

The one-way clutch 64 transmits the rotation of the gear 61 in the direction of arrow 65 to the shaft 57 but does not transmit the rotation in the opposite direction.

The other end of the shaft 55 is rotatably supported on a lever 68 to which a counterclockwise rotation is given by a biasing force of a spring 67 about a rotation shaft 66 of the gear 59 as a rotation center. Therefore, the length between the shafts of the gears 59 and 60 is kept constant even when the levers 54 and 68 rotate.

When the main roller 5 rotates in the direction of the arrow 29, the gear 64 rotates in the direction of the arrow 65 via the gears 23 and 59. This rotation is transmitted to the shaft 5 via the one-way clutch 64.
7 and the auxiliary roller 58 also rotates in the direction of arrow 65 at the same time. On the other hand, the rotation of the gear 60 in the same direction as that of the gear 64 is disengaged by the one-way clutch 62 so that the shaft 55 does not rotate. 13. Since the contact is made with a predetermined pressing force by the spring 67, the auxiliary roller 5
6 rotates in the direction of arrow 63 following the rotation of the auxiliary roller 58 in the direction of arrow 65. The rotation of the plurality of auxiliary rollers imparts a transfer force to the sheet P in the normal feeding direction.

When the main roller 5 rotates in the direction of arrow 31, the gear 60 rotates in the direction of arrow 63. This rotation is transmitted to the shaft 55 via the one-way clutch 62, and the auxiliary roller 56 also rotates in the direction of the arrow 63.

On the other hand, since the rotation of the gear 64 in the same direction as the gear 60 is disengaged by the clutch 64, the shaft 57 does not rotate, but the auxiliary roller 58 rotates in the direction of the arrow 65 following the rotation of the roller 56. I do. The rotation of the plurality of auxiliary rollers imparts a transfer force to the sheet P in the normal feeding direction.

A plurality of free rollers 69 rotatably fitted on the shaft 55 and a plurality of free rollers 70 rotatably fitted on the shaft 57 opposed thereto are pressed against the floating of the sheet P while holding the sheet P floating. Rotate freely as you move.

The plunger 36 moves the movable member 37 upward in response to a control signal from the controller. By this movement, the lower end of the movable member 37 hits the lower surface of the distal end of the lever 68, and the lever 68 and the lever 54 rotate clockwise. Since the auxiliary rollers 56 and 58 are separated by this rotation, the movement of the sheet P is performed only by the conveying force of the main roller 5.

<Operation of Third Embodiment> Next, a sheet conveying operation of the third embodiment will be described with reference to FIGS. When the sheet P is inserted from the paper feed port 2a along the feeding table 3 and the paper guide 3a, the sensor S2 detects the leading edge of the sheet, and the controller 24 causes the motor M to operate.
1 is started, and the main roller 5 is rotated in the direction of arrow 29.

The rotation of the main roller 5 rotates the auxiliary roller 58 in the direction of the arrow 65 through the gear 23, the gear 59, the gear 61, the one-way clutch 64, and the support shaft 57. The rotation of the auxiliary roller 58 conveys the leading end of the sheet P in the direction of the main roller 5. When the sensor S1 detects the leading end of the sheet during the conveyance, the controller 24
1 is sent out by the length L. The auxiliary roller 58
During rotation of the auxiliary roller 56, the auxiliary roller 56 rotates in the direction of the arrow 63 following the rotation of the auxiliary roller 58 via the sheet P.

Next, the controller 24 rotates the main roller 5 in the direction of the arrow 31 by a predetermined amount.
6, the auxiliary roller 56 also rotates in the same direction, so that the rotation imparts a transition force T to the sheet P in the normal feeding direction. During the rotation of the auxiliary roller 56, the auxiliary roller 58 rotates in the direction of arrow 65 following the rotation of the auxiliary roller 56 via the sheet P.

When the left and right ends of the sheet P move back and forth through the contact position between the main roller 5 and the pressing roller 11 during the reverse rotation of the main roller 5, the sheet end is moved by the transfer force of the auxiliary roller 56. Stay along the contact position.

The biasing force of the spring 13 and the spring 67 is set so that the front end of the sheet is not bent by the transition force.

After a predetermined amount of reverse rotation, the main roller 5 rotates in the forward direction by a predetermined amount using the above state as a starting position for cueing the sheet. Due to the transition force, the sheet passes through the contact position along the contact position, and is fed to the print recording position of the recording head 14 without skew and with high accuracy.

The operation from the completion of printing to the subsequent sheet ejection is the same as that of the first embodiment, and a description thereof will be omitted.

A fourth embodiment (reference example) will be described with reference to FIGS. FIG. 8 is a cross-sectional view of the apparatus, and FIG. 7 is a schematic view showing a sheet feeding mechanism and a sheet feeding mechanism of the present apparatus. 8 and 7, members having the same shape and function as those shown in FIGS. 1 and 2 are denoted by the same reference numerals.

In FIG. 8, reference numeral 71 denotes a body cover.
Is a paper discharge port.

In the main body cover 71, a plurality of sheets K
A paper support 73 for holding a sheet rear end, a pressure plate 74 pivotally supported by a shaft 74a on the hopper 72, a paper feed roller 76 having a half-moon-shaped cross section, Paper feed roller 76
Shaft 75 to which the pressure plate 7 is fixed
4 are provided with separation claws 78.

Further, an auxiliary roller 80 that conveys the sheets separated and fed one by one by the rotation of the paper feed roller 76 and the separation claw 78, a support shaft 79 to which the auxiliary roller 80 is fixed, and , Supported by the spring plate 81,
A pinch roller 82 pressed against the auxiliary roller 80
, A guide plate 83 for guiding the sheet, a sensor S1 for detecting the movement of the sheet, a platen 8 for holding a printing position of the sheet, a main roller 5 for conveying the sheet, and a support to which the main roller is fixed. A shaft 6, a holding plate 9 to which a rotating force is applied in the direction of the main roller 5 by a spring 10 about a fulcrum 9 a, and a sheet mounted on a free end of the holding plate 9 to strike a sheet against the main roller 5. Pressing roller 11 to contact
And a carriage 13 guided by a plurality of guide shafts 12 and movable in the sheet width direction, and a recording head 14 mounted on the carriage 13 and performing printing in accordance with image information.

The surface of the auxiliary roller 80 is made of a material having high friction such as rubber.

In FIG. 7, the motor M1 is a motor gear 2
The main roller 5 is rotated based on a control signal from the controller 84 via the first and second gears 22 and the main roller gear 23 fixed to the shaft 6.

The controller 84 also controls the motor M2, and the rotation of the motor M2 is transmitted to the paper feed roller gear 88 by the motor gear 85, gear 86, and intermediate gear 87.

The feed roller gear 88 is rotatably mounted on the shaft 75.

The rotation of the feed roller gear 88 is transmitted to the feed roller 76 via a one-turn spring clutch 89 and a support shaft 75.

FIG. 10 is a cross-sectional view of the one-rotation spring clutch 89. A spring 96 and a bin 9 are provided inside a cam ring 99.
8, a cylinder 97 fixed to the shaft 75 is provided. The spring 96 is wound around the boss of the paper feed gear 88 and the cylinder 97, and one end 96 a of the spring 96 is connected to the cam ring 99 and the other end 96 b is connected to the cylinder 97.

In the above configuration, if the tip of the lever 91 is hooked on the projection 99a of the cam ring 99 during the rotation of the support shaft 75 due to the rotation of the paper feed gear 88 in the direction of the arrow 92, the rotation of the cam ring 99 is stopped. I do. On the other hand, the rotation of the support shaft 75 connected via the cam ring 99, the spring 96, and the cylinder 97 also stops. Since the rotation of the end 96a of the spring 96 also stops due to the stop, the force of the spring 96 wound around the boss of the sheet feeding gear 88 is loosened, and only the sheet feeding gear 88 continues to rotate.

On the other hand, when the feed gear 88 is rotated by a predetermined amount in the direction of arrow 93 by the motor M2, the tip of the lever 91 is disengaged from the protruding portion 99a, so that the spring 96 is tightened and the feed gear 88 and the support shaft 75 are connected. And then the arrow 92
The paper feed roller is also rotated by the rotation in the direction.

The roller 84 rotatably provided on the shaft 79 guides the sheet K to the transport roller 5 while following the movement of the sheet K.

<Operation of Fourth Embodiment> Next, a sheet conveying operation of the apparatus of the fourth embodiment will be described with reference to FIGS. In response to a paper feed command from the host computer, the controller 84 rotates the motor M1 to rotate the main roller 5 in the direction of arrow 29. at the same time,
The controller 84 rotates the motor M2, and feeds the paper feed gear 88.
Is rotated by a predetermined amount in the direction of arrow 93, the tip of the lever 91 is disengaged from the projection 99a, the spring 96 is tightened, and the rotation of the paper feed gear 88 is transmitted to the paper feed roller 76. Start turning around. When the maximum radius portion of the feed roller 75 contacts the upper surface of the plurality of sheets K,
The upper surface paper of the sheet K moves in the direction of the separation claw 78,
, Only one sheet is separated, and the separated sheet is conveyed in the direction of the main roller 5 by the feed roller 76 and the auxiliary roller 80.

When the sensor S1 detects the leading end of the sheet K, the controller 84 controls the rotation amount of the motor M1 to feed the leading end of the sheet by the length L shown in FIG. The leading end protruding amount N of the sheet is described in detail in the description of the first embodiment, and thus the description is omitted.

Next, the controller 84 reversely rotates the motor M1, rotates the main roller 5 by a predetermined amount in the direction of the arrow 31, and moves the sheet K in the reverse feeding direction. At the same time, the controller 84 rotates the motor M2, rotates the auxiliary roller 80 in the direction of the arrow 94, and applies a transfer force to the sheet K in the normal feeding direction.

There are the following two methods for applying the transfer force to the sheet K by the auxiliary roller 80.

In the first method, the peripheral speed of the auxiliary roller 80 is set to a normal peripheral speed. On the other hand, when the spring force of the spring plate 81 that applies a pressing force to the pinch roller 79 that presses the sheet K against the auxiliary roller 80 is made as small as possible within a range that satisfies the forward conveyance force, the surface of the sheet K is The roller 80 slips and gives the sheet K a forward moving force.

When a sheet having a low surface hardness is used in the above-described method, the sheet may be scratched due to the slip and may cause scratches.

As means for preventing the occurrence of the scratch, when the controller 84 controls the motor M2 to reduce the rotational peripheral speed of the auxiliary roller 80, the peripheral surface of the auxiliary roller 80 slips on the sheet surface. By reducing the number, the force for scraping the sheet surface is weakened, and thus the occurrence of the scratch can be prevented.

Next, the second method in which the auxiliary roller 80 applies the transfer force to the sheet K is as follows. The rotation of the main roller 5 in the direction of the arrow 31 causes the auxiliary roller 80 to move in the reverse feed direction. Is driven by applying a transition force in the forward direction to the sheet, and the motor M is rotated in the direction opposite to the arrow 94.
2 is controlled.

In the above method, the rotation force in the normal feeding direction given by the auxiliary roller 80 to the sheet K by the motor M2 is applied to the motor M2 so that the rotation force given by the sheet K to the auxiliary roller 80 in the reverse feeding is smaller. The current or voltage or both the current and the voltage are controlled by the controller 84.

When the leading edge of the sheet passes through the contact position between the main roller 5 and the pressing roller 11 due to the rotation of the main roller 5 in the direction of the arrow 31, even if there is a time lag between the left and right sides of the leading edge of the sheet, the auxiliary roller 80 remains Since the transfer force is applied to the sheet K at substantially the center of the sheet, when the sheet K exits over the entire width of the leading end of the sheet K, the sheet K is entirely rotated around the contact point of the auxiliary roller 80, and further the transfer force is applied by the transfer force. Since the leading end of the sheet is pressed to the contact position between the main roller 5 and the pressing roller 11, the sheet stays along the contact position.

When the main roller 5 is rotated by a predetermined amount in the direction of arrow 29 from the above state, the right and left ends of the sheet K are moved along the contact position by the transition force in the forward direction of the auxiliary roller 80. In this state, the sheet passes through the contact position and is further conveyed to the print position of the recording head 14 with high accuracy without skew.

Next, based on the print signal, the sheet K is fed by the main roller 5 by a predetermined amount in the forward
The printing head 14 performs printing by reciprocating in the sheet width direction of No. 3.

While the sheet K is being conveyed by the main roller 5,
Although the motor M2 is stopped, the rotation of the auxiliary roller 80 in the direction of arrow 94 is free by the one-way clutch 95, and the auxiliary roller 80 follows the movement of the sheet K in the forward direction by the main roller 5. Therefore, the auxiliary roller 80 does not impose a load on the conveyance force of the main roller 5, so that the main roller 5 can feed the sheet with high accuracy.

In the above-described embodiment, the apparatus for applying the transfer force to the sheet by the auxiliary roller 80 has been described. However, the auxiliary roller 80 and the pinch roller 82 are omitted, and the paper feed roller 76 has the same function and function as the auxiliary roller 80. The same effect can be obtained by performing the operation.

As described in detail above, in the apparatus of the present invention, an auxiliary roller is provided on the upstream side of the main roller, and the auxiliary roller moves to the leading end of the sheet in the normal feeding direction when the main roller reversely rotates. By forcing the force, the sheet leading edge is aligned with the generatrix of the main roller with high precision, and while maintaining the above state, the main roller is rotated forward to a predetermined printing position with high precision. Thus, it is possible to provide a very excellent sheet conveying apparatus capable of conveying a sheet.

The same effect can be obtained by applying the functions and operations of the main roller and the auxiliary roller according to the embodiment of the present invention to registration rollers used in a printing apparatus such as a copying machine.

[0106]

As described above, according to the present invention,
When the sheet is transported in the reverse direction of the sheet transport direction by the reverse rotation of the main roller, the auxiliary roller is rotated or moved in the reverse direction of the sheet transport direction, and the rotation or movement stores the transport force in the forward direction, so that the sheet is When the sheet passes through the holding section, the stored conveying force is applied to the sheet, and the leading end of the sheet stays along the holding section. By correcting the skew by this operation, highly accurate sheet conveyance can be performed regardless of the type of sheet.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view of a recording apparatus to which a first embodiment of a sheet conveying apparatus according to the present invention is applied.

FIG. 2 is a perspective view of the sheet conveying device.

FIG. 3 is a longitudinal sectional side view of a recording apparatus to which a second embodiment of the sheet conveying apparatus according to the invention is applied.

FIG. 4 is a perspective view of the sheet conveying device.

FIG. 5 is a longitudinal sectional side view of a recording apparatus to which a third embodiment (reference example) of the sheet conveying apparatus according to the invention is applied.

FIG. 6 is a perspective view of the sheet conveying device.

FIG. 7 is a perspective view of a sheet conveying apparatus according to a fourth embodiment (reference example) of the present invention.

FIG. 8 is a longitudinal sectional side view of a recording apparatus to which the sheet conveying apparatus is applied.

FIG. 9 is a plan view of a sheet and a sheet feeding unit according to the present invention.

FIG. 10 is a longitudinal side view of the same spring clutch part.

FIG. 11 is a perspective view of a recording apparatus to which a conventional sheet conveying apparatus is applied.

FIG. 12 is a side view showing a main part of another conventional sheet conveying apparatus.

[Explanation of symbols]

 P sheet M1, M2 Motor 1 Recording device 5 Main roller 9 Pressing plate (pressing means) 16 Ring 17 Auxiliary roller 18 Spring member 24 Controller (control means) 42 Auxiliary roller 48 Spring member 56, 58 Auxiliary roller 80 Auxiliary roller 84 Controller ( Control means) 89 one-turn spring clutch

Claims (5)

(57) [Claims] A main roller configured to be rotatable in a direction in which the sheet is conveyed and in a direction opposite to the main roller; a pressing unit that is in contact with the main roller and forms a nip portion to nip the conveyed sheet; An auxiliary roller disposed upstream of the main roller in the sheet conveyance direction, wherein the auxiliary roller rotates in the direction in which the main roller conveys the sheet and rotates in the sheet conveyance direction when the sheet is being conveyed. Then, when the sheet is conveyed in a direction opposite to the sheet conveying direction, by rotating or moving by the sheet conveyed in the reverse direction, the sheet is configured to store a conveying force in the sheet conveying direction with respect to the sheet. And after the main roller nips the sheet at the nip portion formed by the main roller and the pressing means, the main roller reversely rotates by a predetermined amount to pull the sheet out of the nip portion. When the sheet is conveyed, the auxiliary roller receives a force from the sheet conveyed in the reverse direction and accumulates a conveying force in the sheet conveying direction, and when the sheet comes out of the pinching portion, the accumulated sheet conveys the sheet. A sheet conveying device, wherein a front end of the sheet conveying device is arranged along the holding portion. 2. The sheet conveying device according to claim 1, wherein the conveying force in the sheet conveying direction stored by the auxiliary roller is generated by a spring member connecting the shaft supporting the auxiliary roller and the auxiliary roller. apparatus. 3. The shaft is configured to rotate in a direction in which a sheet is conveyed, and not to rotate in a direction opposite to the sheet conveying direction. The sheet conveying device according to claim 2, wherein a plurality of the rollers are supported so as to rotate independently of each other, and the spring member is provided on each of the plurality of auxiliary rollers. 4. A conveying force in the sheet conveyance direction in which the auxiliary roller store, the shaft supporting the auxiliary roller is movable in the sheet conveying direction and a direction substantially parallel, <br/> sheet of said shaft 2. The sheet according to claim 1, wherein the shaft and a holding unit that holds the shaft are connected by a spring member so as to accumulate a conveying force in a sheet conveying direction with respect to a movement in a direction opposite to the conveying direction. Transport device. 5. The conveyance force stored in the spring member is set to a value such that the sheet tip does not bend while the sheet tip stays along the holding portion. The sheet conveying device according to any one of claims 2 to 4, wherein