JP2001080189A - Sheet conveying mechanism and printer using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent jamming and to provide a sheet conveying mechanism for a printer capable of effectively conveying a printing sheet by resetting an end of the sheet to an original even by disengaging the end of the sheet from a roll on a delivery sheet. SOLUTION: Both surfaces of a printing sheet 22 are brought into pressure contact with a roll 47 underneath a delivery sheet and a roll 50 on the delivery sheet. A conveying force is operated at the sheet 22 by a rotation of the roll 47 to convey the sheet 22, and both ends of the sheet 22 of the roll 50 are brought into contact with a pair while rotating. In this case, the roll 50 has a circumferential surface 50a of the same diameter having a width in a rotating shaft direction at its outer periphery, and a conical surface 50b disposed at an inside of the surface 50a and gradually reducing in its diameter toward an inside of the rotary shaft direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a paper transport mechanism for transporting paper and a printing apparatus using the same.

[0002]

2. Description of the Related Art In a stencil printing machine, for example, a stencil sheet is heat-perforated by a heat-sensitive head in accordance with a desired image, and the heat-perforated stencil sheet is wound around an outer peripheral surface of a plate cylinder. Supply printing paper from the paper feeding unit so as to press against
The image is printed by transferring the ink to the printing paper from the heat-sensitive perforation of the stencil sheet in the process of passing the press-contact, and a paper transport mechanism is used to transport the printed printing paper to a predetermined position.

FIG. 18 is a schematic configuration diagram of a paper transport mechanism of a conventional stencil printing apparatus, and FIG. 19 is a plan view of the paper transport mechanism.

In FIG. 18 and FIG. 19, a press roll 101 is disposed below a plate cylinder 100 around which a stencil sheet (not shown) is wound.
Numerals 1 are provided rotatably in the directions of arrows in FIG. A paper feed unit (not shown) is provided in a space on the left side of the plate cylinder 100 and the press roll 101, and print paper 102 is supplied between the plate cylinder 100 and the press roll 101 from this paper feed unit.

A paper discharge unit 103 is provided in a space on the right side of the plate cylinder 100 and the press roll 101.
3, the printing paper 102 on which printing has been performed after passing between the plate cylinder 100 and the press roll 101 is discharged.

The paper discharge unit 103 includes a paper delivery mechanism 106 including a separation fan 104 and a separation claw 105, a conveyance lower roll 107 disposed below two places in the conveyance direction,
The upper transport roll 1 disposed at two locations facing the upper side
08, and a paper transport mechanism 109 comprising: The two transport lower rolls 107 rotate in the direction of the arrow in FIG. 18 by the driving force from a motor (not shown). As shown in FIG. 19, the transfer upper rolls 108 at the two locations
The upper and lower transport rolls 108 are arranged so as to be inclined outward from each other with respect to the paper transport direction.

Next, the operation of the above configuration will be described. FIG.
As shown in FIG. 7, the plate cylinder 100 and the press roll 101 rotate, and the printing paper 102 is supplied between the plate cylinder 100 and the press roll 101 from the paper supply unit. When the printing paper 102 is printed when passing between the plate cylinder 100 and the press roll 101, and the leading end side of the printing paper 102 on which printing has been completed is discharged to the discharge unit 103 side, the blowing of the separation fan 104 and the separation claw are performed. Due to the interference of 105, the printing paper 102
Peeled from 00. Separation fan 104 and separation claw 10
The printing paper 102 peeled off by the paper transport mechanism 5
09 is guided between the lower transport roll 107 and the upper transport roll 108. Then, a conveyance force is applied to the printing paper 102 by the rotation of the conveyance lower roll 107, and the conveyance upper roll 108 rotates together with the movement of the printing paper 102 to continue the movement. In this way, the printing paper 102 is transported to a predetermined position and discharged.

In the course of the transport operation of the paper transport mechanism 109, since the left and right transport upper rolls 108 are arranged to be inclined in the paper transport direction, the left and right transport upper rolls 108 are applied to the printing paper 102 by external forces outwardly facing each other. Act. This prevents the printing paper 102 from being wrinkled or bent.

[0009]

However, in the paper transport mechanism of the conventional stencil printing apparatus, if the external force of the left and right transport upper rolls 108 becomes unbalanced for some reason, the printing paper 102 is not moved. A situation occurs in which one of the upper transport rolls 108 comes off from one end. Once the printing paper 102 is detached from the upper transport roll 108, the oblique arrangement of the upper transport roller 108 causes an external force to act in a direction in which the print paper 102 is further removed, and thus there is a problem that jamming easily occurs.

Further, an external force is applied to the printing paper 102 for some reason, or an upstream trouble causes a problem in FIG.
As shown in FIG.
When the value is out of 08, the printing paper 102 cannot be brought to the correct paper conveyance state as shown in FIG.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and a paper transport mechanism capable of reliably transporting paper without jamming even if the paper comes off a transport roll, and a printing method using the same. It is intended to provide a device.

[0012]

According to a first aspect of the present invention, a sheet is interposed between conveying members arranged vertically and a conveying force is applied to the sheet by at least one of the conveying members to convey the sheet. In a paper transport mechanism configured as a pair of transport rolls configured to rotate and contact at least one of the transport members arranged above and below at both ends of the paper, the pair of transport rolls rotate around their outer peripheral surfaces. A circumferential surface having the same diameter having a width in the axial direction and an inclined surface formed on the side where the pair of transport rolls face each other, and gradually reducing the diameter according to the direction in which the pair of transport rolls face each other. Features.

In this paper transport mechanism, the circumferential surfaces of the pair of transport rolls are in contact with both ends of the paper, and for some reason, the circumferential surface of one transport roll is moved from one circumferential end of the paper to one end of the paper. When one end of the sheet comes into contact with the inclined surface of one of the transport rolls, the sheet receives centrifugal force from the rotating inclined surface and the transport brake is applied from the inclined surface having a peripheral speed lower than the transport speed of the sheet. Upon receiving the force, the resultant force of the centrifugal force and the moment due to the conveyance brake force acts on the sheet in a direction returning to the circumferential surface along the inclined surface.

According to a second aspect of the present invention, in the paper transport mechanism according to the first aspect, a space between the circumferential surface and the inclined surface of each of the transport rolls is formed as a radius surface.

In this paper transport mechanism, in addition to the effect of the first aspect, the paper returns from the inclined surface to the circumferential surface through the radius surface by the combined force of the centrifugal force and the moment due to the transport braking force.

According to a third aspect of the present invention, the printing paper is transported by a paper transport mechanism, and the paper transport mechanism interposes the printing paper between the transport members arranged above and below, and the printing paper is transported by at least one transport member. The printing paper is transported by applying a transporting force to the paper, and at least one of the transport members arranged above and below is configured as a pair of transport rolls that come into contact with both ends of the printing paper while rotating. The transfer roll is formed on the side where the pair of transfer rolls face each other, and the outer peripheral surface is formed on the side where the pair of transfer rolls face each other, and the diameter gradually increases in the direction in which the pair of transfer rolls face each other. Characterized by having an inclined surface for reducing

In this printing apparatus, each circumferential surface of the pair of transport rolls is in contact with both ends of the printing paper, and for some reason, the circumferential surface of one transport roll is moved from one circumferential surface of the printing paper to one end of the printing paper. When one end of the printing paper comes in contact with the inclined surface of one of the transport rolls, the end of the printing paper receives centrifugal force from the rotating inclined surface, and the peripheral surface of the printing paper transports at a speed lower than the transport speed of the printing paper. Upon receiving the conveyance brake force, the resultant force of the centrifugal force and the moment due to the conveyance brake force acts on the printing paper in the direction of returning to the circumferential surface along the inclined surface.

According to a fourth aspect of the present invention, in the printing apparatus according to the third aspect, a space between the circumferential surface and the inclined surface of each of the transport rolls is formed as a round surface.

In this printing apparatus, in addition to the effect of the third aspect of the invention, the printing paper returns from the inclined surface to the circumferential surface through the round surface by the combined force of the centrifugal force and the moment due to the transport braking force.

The invention of claim 5 is the invention of claim 3 or claim 4.
In the printing apparatus according to the above, the paper transport mechanism may be provided in a paper discharge unit that transports the print paper on which printing has been completed, and the pair of transport rolls may be arranged so as to contact a print surface side of the print paper. Features.

In this printing apparatus, claim 3 or claim 4
In addition to the effect of the invention, the pair of transport rollers contact only the both ends of the printing surface of the printing paper.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 to 17 show an embodiment of the present invention. In this embodiment, the present invention is applied to a paper discharge section of a stencil printing apparatus.

FIG. 1 is a schematic diagram of the entire stencil printing apparatus. 1, a stencil printing apparatus 1 includes a document reading unit (not shown), a stencil making unit 3, a printing unit 4, and a paper feeding unit 5.
, A paper discharging unit 6 and a plate discharging unit 7.

A document reading section (not shown) reads a document as an electric signal. The read information can be processed based on a predetermined command (enlargement, reduction, etc.).

The stencil making section 3 is provided with a stencil sheet accommodating section 11 for accommodating a long stencil sheet 10 wound in a roll shape, and is arranged downstream of the stencil sheet accommodating section 11 in the transport direction of the stencil sheet 10. A guide feed roller 9; a thermal head 12 disposed downstream of the guide transport roller 9; and a platen roller 13 disposed at a position facing the thermal head 12 and rotated by a driving force of a write pulse motor (not shown). And The plate making section 3 has a platen roller 13 and a pair of base paper feed rollers 14, 14 'arranged between the thermal head 12 and a plate cylinder 16, which will be described later. It is rotated in synchronization with the platen roller 13 by the driving force of the pulse motor. Further, the stencil making section 3 has a stencil cutter (not shown) disposed between the pair of stencil feed rollers 14, 14 'and the platen roller 13 and the thermal head 12, and the stencil sheet 10 is formed by the stencil cutter. Disconnect.

The printing section 4 has a plate cylinder 16 and a paper cylinder 17 having substantially the same diameter, and a part of the outer peripheral surface of each is arranged substantially in a close state. The plate cylinder 16 and the paper cylinder 17 are configured to rotate in synchronization with the driving force of a main motor (not shown) in the directions of arrows in FIGS. 1 and 3. The plate cylinder 16 has a pair of cylindrical flanges (not shown) provided facing each other, and a stencil clamp 18 is provided on a part of the outer peripheral surface of the flange. The leading end of the base paper 10 can be clamped. Base paper clamp unit 18
A flexible screen 19 forming the peripheral wall of the plate cylinder 16 is stretched on the outer peripheral surface of the flange of the plate cylinder 16 except for the above. The screen 19 forming the peripheral wall of the plate cylinder 16 is configured to be able to pass ink at least in a printing region when a printing pressure is applied. An intermediate press roll 20 is provided inside the screen 19 of the plate cylinder 16, and the intermediate press roll 20 presses the screen 19 to the outer peripheral side (the state shown in FIG. 1) and waits to retreat inside the screen 19. Transition to and from position. In addition, middle press roll 2
0 is configured to be supplied with ink. That is, the intermediate press roll 20 applies printing pressure from the inner peripheral surface side of the screen 19 and supplies ink from the inner peripheral surface of the screen 19.

A paper clamp 21 is provided at a predetermined position on the outer peripheral surface of the paper cylinder 17, and the paper clamp 21 can clamp the leading end of a printing paper 22 which is a paper.

The paper supply section 5 includes a paper supply table 23 on which print papers 22 as paper are stacked, a scraper 24 that presses the print paper 22 at an uppermost position from the paper supply table 23, and a downstream of the scraper 24. The pickup roll 25 and the sabaki roll 26 which are arranged and are positioned substantially in proximity to each other.
And this pickup roll 25 and sabaki roll 26
, A guide roll 27 and a timing roll 28 which are located substantially in the vicinity of each other, a stop finger 29 which can regulate the leading end of the printing paper 22 at the position of the timing roll 28, a pickup roll 25 and a sabaki roll And a paper detection sensor 30 that detects a position between the position of the guide roll 27 and the positions of the guide roll 27 and the timing roll 28. The guide roll 27 can move between a pressing position where the guide roll 27 is pressed against the timing roll 28 and a separation position where the guide roll 27 is separated from the timing roll 28. The paper detection sensor 30 includes a light emitting element 30a and a light receiving element 30b.
And detects the leading end of the conveyed printing paper 22.

The printing paper 22 moved by the rotation of the scraper 24 is allowed to be conveyed only by the pickup roll 25 and the sabaki roll 26 to the printing paper 22 at the uppermost position.
The paper is conveyed in synchronization with the rotation of the paper cylinder 17 by the rotation of the guide roll 27 and the timing roll 28.

The paper discharge section 6 includes a paper delivery mechanism 31 arranged at a position close to the outer peripheral surface of the plate cylinder 16 and the paper cylinder 17 which are substantially close to each other, and prints received and delivered by the paper delivery mechanism 31. Paper transport mechanism 3 for transporting paper 22
2 and a stacker section 33 on which the printing paper 22 transported by the paper transport mechanism 32 is placed in a stacked state.

The plate discharge section 7 is a base paper clamp section 1 of the plate cylinder 16.
8, a windmill-shaped member 35 for guiding the leading end of the stencil 10 released, and a guide belt 36 for transmitting a rotational force to the windmill-shaped member 35 and assisting the conveyance of the stencil 10.
A pair of upper and lower stencil transport belts 37, 37 for transporting the stencil paper 10 transported by the windmill-like member 35 and the guide belt 36 to the stencil discharge box 38, and the stencil paper 10 transported by the stencil transport belt 37 are stored. And the stencil sheet 10 to be transferred to the stencil
And a plate discharging compression member 39 to be pushed into the back of the plate.

Next, the paper transfer mechanism 31 and the paper transport mechanism 32 will be described. FIG. 2 shows the paper transfer mechanism 3
1 and a perspective view of a paper discharge unit of the paper transport mechanism 32, FIG.
4 is a schematic side view of the sheet discharging unit, FIG. 4 is a front view of a pair of plate cylinder side regulating guides, FIG. 5 is an enlarged view of a main part thereof, and FIG. FIGS. 7A and 7B are plan views showing the arrangement of the upper transport roll 50 of the paper transport mechanism 32. FIG.

In FIGS. 2 to 7, the paper discharge unit A is
It has a pair of left and right side plates 40, 40 arranged at intervals, and the pair of side plates 40, 40 is provided with a plurality of support rods 41.
Are connected by The plurality of support rods 41 support a pair of left and right upper guide block members 42, 42. The pair of upper guide block members 42, 42 are respectively guided by the support rod 41 and movably provided in the left-right direction. I have. That is, a pair of upper guide block members 4
2 and 42 are configured so that the distance between them can be freely adjusted, whereby the widths of the paper transfer mechanism 31 and the paper transport mechanism 32 themselves can be adjusted according to the width of the printing paper 22 to be used. ing.

The paper transfer mechanism 31 has an upper protruding portion 43 protruding from the pair of upper guide block members 42, 42 toward the plate cylinder 16. The pair of upper protruding portions 43, 43 A pair of left and right plate cylinder side regulating guides 44, 44 are provided to regulate only the both ends of the printing sheet 22 to bend toward the plate cylinder 16 side in the sheet feeding direction and guide the sheet to the sheet conveying mechanism 32. I have. The pair of left and right plate cylinder side regulating guides 44, 44 are arranged at positions close to each other so as to face the substantially adjacent outer peripheral surface of the plate cylinder 16 and the paper cylinder 17. The sheet delivery mechanism 31 has a lower block member 45 provided below the upper protruding portion 43 of the pair of upper guide block members 42, 42, and the lower block member 45 feeds the printing paper 22. A paper cylinder-side regulating guide portion 4 that regulates the bending to the paper cylinder 17 side by a predetermined amount or more with respect to the transport direction and guides the paper to the paper transport mechanism 32.
6 are provided. The paper cylinder side regulating guide part 46 is arranged at a position close to the substantially outer peripheral surface of the plate cylinder 16 and the paper cylinder 17.

Specifically, as shown in FIGS. 4 and 5, a pair of left and right plate cylinder side regulating guides 44, 44 are provided with a pair of horizontal guide surfaces 44a,
44a and the inside of each of the pair of horizontal guide surfaces 44a, 44a,
And a taper guide surface 44b directed in a direction in which the amount of bending toward the side (upper side) increases. Paper cylinder side regulation guide section 46
As shown in FIG. 2, a linear taper surface 46a gradually rising upward from the paper cylinder side toward the paper transport mechanism side.
Having.

The paper transport mechanism 32 includes a pair of left and right side plates 4.
There is a lower discharge roller 47, which is a transport member rotatably supported at 0 and 40, and the lower discharge roller 47 is arranged at two locations with a space in the discharge direction. These two lower discharge rollers 47 are synchronously rotated by a drive belt 48 in the same rotational direction, and the drive belt 48 is driven by a driving force of a discharge motor (not shown).

Further, a pair of left and right upper guide block members 4
Roll support members 49 are arranged in the inside of each of the roll discharge members 2 and 42. Each of the roll support members 49 is a transport member at two locations spaced apart in the paper discharge direction, and a discharge upper roll 50 that is a transport roll. Are rotatably provided. Each of the upper discharge rollers 50 is shown in FIGS.
(A), (B), as shown in FIGS. 17 (A), (B),
Circumferential surface 5 of the same diameter whose outer peripheral surface has a width in the rotation axis direction
0a and a conical surface (inclined surface) 50b that is arranged inside the circumferential surface 50a and gradually decreases in diameter toward the inside in the rotation axis direction. 15 and 16
As shown in (A) and (B), a round surface 50c is formed between the circumferential surface 50a and the conical surface 50b of each transport roll 50.

Each of the upper discharge rollers 50 is provided so as to be movable between a contact position where it contacts the lower discharge roller 47 and a separation position where it separates. A compression spring 51 (shown in FIGS. 3 and 6) is interposed between the upper guide block member 42 and the roll support member 49, and the discharge upper roll 50 is brought into contact with the lower discharge roller 47 by the compression spring 51. Has been energized. The driving force from the driving source is not transmitted to the upper discharge roller 50, and the upper discharge roller 50 is rotated only when receiving the rotational force of the lower discharge roller 47 or the moving force of the printing paper 22. or,
Each of the pair of upper guide block members 42, 42 on the side of each of the upper discharge rollers 50, that is, the inner side is configured as a side fence 55.
Are prevented from further displacing in the direction perpendicular to the sheet transport direction. In FIG. 2, reference numeral 52 denotes a lower conveying guide, and 53 denotes an upper guide.

Next, the operation of the stencil printing apparatus 1 will be briefly described. In the stencil making section 3, the stencil sheet 10 is conveyed by the rotation of the platen roller 13 and the stencil feed roller 14, and a large number of heating elements of the thermal head 12 selectively generate heat based on image information read by a document reading section (not shown). The stencil sheet 10 is thermally perforated by the operation, and one stencil length of the stencil sheet 10 is cut by a stencil cutter to produce a stencil sheet 10 having a desired size.

In the printing section 4, the leading end of the stencil sheet 10 produced by the stencil section 3 is clamped by the stencil clamping section 18 of the plate cylinder 16, and in this clamped state, the plate cylinder 16 is rotated to stencil the stencil sheet 10. The plate is wound around the outer peripheral surface of the screen 19 of the body 16 to form a plate.

The paper supply section 5 conveys the printing paper 22 in synchronization with the rotation of the plate cylinder 16 and the paper cylinder 17, and clamps the leading end of the printing paper 22 by the paper clamp section 21 of the paper cylinder 17. And between the paper cylinder 17.

On the other hand, in the printing section 4, the intermediate press roll 20 is positioned at the press position during printing, and the plate cylinder 16 is rotated. Then, the intermediate press roll 20 rotates on the inner peripheral surface of the screen 19 while pressing the inner peripheral side of the screen 19. Since ink is constantly supplied to the outer peripheral surface of the intermediate press roll 20, the ink is transferred to the screen 19 by this rotation. Further, the screen 19 is swelled to the outer peripheral side by the pressing of the intermediate press roll 20, and is brought into pressure contact with the paper cylinder 17. Then, the printing paper 22 conveyed from the paper supply unit 5 as described above is conveyed while being pressed against the stencil sheet 10 by the intermediate press roll 20, and the printing paper 2
2 is printed with an image. When the leading end of the printing paper 22 passes the position of the intermediate press roll 20 and reaches downstream thereof, the paper clamp unit 21 is released.

In the paper discharge section 6, the printing paper 22 is received and delivered by the paper delivery mechanism 31 on the downstream side of the printing portion, and the delivered printing paper 22 is transferred to the paper transport mechanism 32.
And discharged to the stacker unit 33.

In starting the new plate making, the plate discharging section 7 discharges the used stencil sheet 10 used for the previous printing, which is wound around the outer peripheral surface of the screen 19 of the plate cylinder 16 and mounted. In that case, in this case, the stencil clamping unit 1 of the plate cylinder 16 is required before a new stencil sheet having been stenciled on the outer peripheral surface of the screen 19 of the plate cylinder 16.
8 is released, and the leading end side of the stencil sheet 10 unclamped is guided by a windmill-like member 35 or the like while rotating the plate cylinder 16,
A plate discharging box 38 via a pair of plate discharging belts 37, 37
To be stored.

Next, detailed operations of sheet feeding, printing, and sheet discharging will be described with reference to FIGS. As shown in FIG.
The plate cylinder 16 and the paper cylinder 17 rotate, and the intermediate press roll 20 also rotates in synchronization with the plate cylinder 16, while the scraper 24 and the pickup roll 25 rotate, and the pressurizing plate (not shown) and the sabaki roll 26 act on the uppermost roll. Only one print sheet 22 at the position is conveyed. When the leading end of the transported printing paper 22 reaches the detection position of the paper detection sensor 30, the paper detection sensor 30 detects the rotation, and stops the rotation of the scraper 24 and the pickup roll 25 at the time when the printing paper 22 is transported by a predetermined distance from this detection time. . Then, as shown in FIG. 9, the leading end of the printing paper 22 is
Stopped in contact with.

Next, the guide roll 27 is moved from the separated position to the pressure contact position, the guide roll 27 sandwiches the printing paper 22 with the timing roll 28, and the stop finger 29 is moved to the standby position. And FIG.
As shown at 0, the guide roll 27 and the timing roll 28 rotate, and the printing paper 22 is transported toward the outer peripheral surface of the paper cylinder 17 along a predetermined paper transport direction. In this operation process, the scraper 24 and the pickup roll 25 are idled so that the back tension is not applied to the printing paper 22.

When the leading edge of the printing paper 22 is conveyed to the outer peripheral surface of the paper cylinder 17, the paper clamping unit 21 of the paper cylinder 17 clamps the leading edge of the printing paper 22. As shown in FIG. 11, the clamped printing paper 22 is moved together by the rotation of the paper cylinder 17, and applies a printing pressure to the intermediate press roll 20 when passing through the press-contact outer peripheral portion of the plate cylinder 16 and the paper cylinder 17. Ink is transferred from the perforated portion of the stencil sheet 10 to print an image. In this operation process, the guide roll 27 is located at the separated position so that the back tension is not applied to the printing paper 22.

When the leading end of the printing paper 22 passes the position of the intermediate press roll 20, that is, the printing position, the paper clamping unit 21 is immediately released as shown in FIGS.
Then, the leading end side of the printing paper 22 becomes straight due to its own elastic return deformation and the like, and the bending toward the plate cylinder 16 side is regulated by the plate cylinder side regulating guide portion 44, and is conveyed while being guided by the sheet conveying mechanism 32. Is done. If, for some reason, the printing paper 22 is not straight and is conveyed while being bent toward the paper cylinder 17, the paper cylinder-side regulating guide 46
The guide is guided to the paper transport mechanism 32 side while being guided and guided. The printing paper 22 guided in this way is shown in FIG.
As shown in the figure, the lower discharge roller 47 and the upper discharge roll 5 are interposed between the lower discharge roller 47 and the upper discharge roll 50.
The movement is continued by the rotation of 0 and sent to the stacker unit 33, thereby completing the printing operation of one sheet. Then, the guide roll 27 moves to the pressure contact position and shifts to the next printing operation, and the above operation is performed for a predetermined number of printed sheets.

In the transport operation of the paper transport mechanism 32, as shown in FIGS. 14, 16A and 17A, the lower surface of the print paper 22 (the side opposite to the print surface) is discharged. The printing paper 22 is pressed against the lower paper roll 47 and receives a conveying force due to the rotation of the lower discharging roll 47, and both ends of the upper surface (printing surface) of the printing paper 22 are pressed against the circumferential surface 50 a of the upper discharging roll 50 to discharge the paper. The paper roll 50 moves by rotating following the movement of the printing paper 22. In this state, as shown in FIG. 15, FIG. 16 (B), and FIG. 17 (B), the circumferential surface 50a of one of the upper discharge rollers 50 for some reason.
When one end of the printing paper 22 comes off from the printing paper 2, the printing paper 2
2 becomes unstable in the direction orthogonal to the transport direction, so that the printing paper 22 is transported while swinging left and right.

When one end of the printing paper 22 comes into contact with the conical surface 50b of one of the upper discharge rollers 50 by this swing, the end returns to the circumferential surface 50a along the conical surface 50b, and FIG. It returns to the state of FIG. 16 (A) and FIG. 17 (A).

That is, when one end of the printing paper 22 comes into contact with the conical surface 50b of one of the upper discharge rollers 50 due to the above swing, the printing paper 22 rotates, for example, as shown in FIG. The centrifugal force Fa is received by contacting the upper discharge paper roll 50, and the end of the printing paper 22 tends to move downward by the centrifugal force Fa. Further, the peripheral speed of the conical surface 50b of the upper discharge roller 50 is slower than the outer peripheral surface speed of the lower discharge roller 47 (the transport speed of the printing paper 22). As shown in FIG. 17B, the end of the printing paper 22 has a reaction force in the direction opposite to the paper transport direction from the conical surface 50b of the upper discharge roll 50, that is, as shown in FIG.
The transfer brake force Fb acts, and the transfer brake force Fb
As a result, a moment Mb (hereinafter, referred to as a moment due to the conveyance brake force Fb) acts on the printing paper 22 to move the printing paper 22 to one of the upper discharge rollers 50. That is, the centrifugal force Fa and the transport brake force F
b of the printing paper 22 by the resultant force with the moment Mb.
Is returned to the circumferential surface 50a along the conical surface 50b, and is returned to the state shown in FIGS. 14, 16 (A) and 17 (A).

When the printing paper 22 returns to its original state, the printing paper 22 is clamped at both ends by the upper discharge roller 50 and the lower discharge roller 47, and the pair of right and left clamping forces causes the oscillating force in the direction perpendicular to the transport direction. Because it is suppressed, it is stable in the direction perpendicular to the transport direction, and the left and right swinging is stopped. Therefore, even if the end of the printing paper 22 is removed from the circumferential surface 50a of the upper discharge roll 50, jamming does not occur and the paper can be reliably transported.

Further, the end of the printing paper 22 is
When the printing paper 22 swings largely right and left due to the transport instability, the end of the printing paper 22 contacts the other side fence 55 to prevent further detachment. At the same time, the printing paper 22 swings to the opposite side (one side) by the reaction force from the side fence 55. Then, the end of the printing paper 22 comes into contact with the conical surface 50b of one of the upper discharge rollers 50, and the above-mentioned force acts on the end, or the swinging power of the printing paper 22 in the left-right direction and the centrifugal force Fa. Is formed on one end of the printing paper 22 along the conical surface 50b.
14 and FIG. 16 (A) and FIG.
It is considered that the state returns to the original state of FIG. When returning to this state, the conveyance posture of the printing paper 22 is stabilized as described above, and the left and right swinging is stopped.

In the above embodiment, the upper discharge roll 50 is used.
Between the circumferential surface 50a and the conical surface 50b.
, The centrifugal force Fa and the transport brake force Fb
The printing paper 22 moves from the conical surface 50b through the radius surface 50c by the resultant force with the moment Mb by the circumferential surface 50a.
Because it returns to, it can return smoothly.

In the above embodiment, the paper transport mechanism 32
Is provided in the paper discharge unit 6 that conveys the printing paper 22 on which printing has been completed, and the pair of upper discharge rollers 50, 50 are arranged so as to be in contact with the printing surface side of the printing paper 22. Since the left and right upper discharge rolls 50 contact only the both ends, there is no possibility that the print surface of the printing paper 22 is stained except for the both ends. Further, in the present invention, the outer peripheral surface of the upper discharge roll 50 is composed of the circumferential surface 50a and the conical surface 50b having a smaller diameter inside the peripheral surface 50a, and the contact width with the printing paper 22 is much smaller than in the conventional example. Therefore, there is no further risk of soiling other than both ends of the printing surface of the printing paper 22,
It also contributes to making the printable area wider.

In the above embodiment, the paper transport mechanism 32
Although the paper discharge lower roll 47 and the paper discharge upper roll 50 are arranged at two locations upstream and downstream, respectively, one or three or more locations may be provided. In addition, one of the transport members is configured as the upper discharge roller 50 and the other of the transport members is configured as the lower discharge roller 47. The other transport member is a member that can press the printing paper 22 against the upper discharge roller 50. Any configuration may be used, for example, a conveyor belt may be used.
Further, although the lower discharge roller 47 is configured on the driving side and the upper discharge roller 50 is configured on the driven side, the reverse may be adopted, or both may be configured to be driven synchronously.

In the above-described embodiment, the case where the present invention is applied to the paper discharge unit 6 of the stencil printing apparatus 1 has been described. However, the present invention can be applied to a part other than the paper discharge unit 6 of the stencil printing apparatus 1. or,
The present invention can be applied to a printing apparatus other than a stencil or an apparatus other than a printing apparatus to a place where a sheet is transported.

In the present specification, the conical surface 50b which is disposed inside the circumferential surface 50a of each of the upper discharge rollers 50 and whose diameter gradually decreases toward the inside in the direction of the rotation axis is defined as:
Both the case where the diameter is reduced by a linear slope toward the inside and the case where the diameter is reduced by a curved slope are included.

[0060]

As described above, according to the first aspect of the present invention, the paper is interposed between the transport members arranged vertically and the transport force is applied to the paper by at least one of the transport members. In a paper transport mechanism configured to transport the paper and configured as a pair of transport rolls that contact at least one of the transport members arranged above and below while rotating at both ends of the paper, the pair of transport rolls includes An outer circumferential surface having a circumferential surface having a width in the rotation axis direction and a circumferential surface having the same diameter, and an inclined surface formed on a side where the pair of transport rolls face each other, and gradually reducing the diameter according to a direction in which the pair of transport rolls face each other; Therefore, in a state in which each circumferential surface of the pair of transport rolls is in contact with both ends of the sheet, one end of the sheet is detached from the circumferential surface of one transport roll for some reason. for When one end of the paper roll comes into contact with the inclined surface of one of the transport rolls, it receives centrifugal force from the rotating inclined surface and also receives transport braking force from the inclined surface having a peripheral speed lower than the paper transport speed. And the moment due to the transport brake force act on the paper in the direction of returning to the circumferential surface along the inclined surface. Therefore, even if the paper comes off the transport roll, jamming does not occur and the paper is transported reliably. be able to.

According to the second aspect of the present invention, in the paper transport mechanism according to the first aspect, the space between the circumferential surface and the inclined surface of each of the transport rolls is formed as a radius surface.
In addition to the effect of the first aspect of the present invention, since the sheet returns from the inclined surface to the circumferential surface through the round surface by the combined force of the centrifugal force and the moment due to the conveyance brake force, the paper returns smoothly.

According to the third aspect of the present invention, the printing paper is transported by the paper transport mechanism, and the paper transport mechanism interposes the printing paper between the upper and lower transport members, and uses at least one of the transport members. Conveying the printing paper by applying a conveying force to the printing paper, configured as a pair of conveying rolls that contact at least one of the respective conveying members arranged above and below while rotating at both ends of the printing paper, The pair of transport rolls are formed on the side where the pair of transport rolls face each other, with the outer peripheral surface having a circumferential surface having a width in the rotation axis direction and the same diameter, and gradually according to the direction in which the pair of transport rolls face each other. Since the circumferential surface of the pair of transport rolls is in contact with both ends of the printing paper, the circumferential surface of one of the transport rolls is in some state When one end of the printing paper comes off and one end of the printing paper comes into contact with the inclined surface of one of the transport rolls, it receives centrifugal force from the rotating inclined surface and has a circumference that is slower than the transport speed of the printing paper. The transport brake force is received from the inclined surface of the surface speed, and the resultant force of the centrifugal force and the moment due to the transport brake force acts on the printing paper in the direction of returning to the circumferential surface along the inclined surface. Even if the sheet comes off, jamming does not occur and the printing sheet can be transported reliably.

According to the fourth aspect of the present invention, in the printing apparatus according to the third aspect, the space between the circumferential surface and the inclined surface of each of the transport rolls is formed as a radius surface. In addition to the effects of the invention, the printing paper returns from the inclined surface to the circumferential surface through the round surface by the combined force of the centrifugal force and the moment due to the transport braking force, so that the printing paper returns smoothly.

According to a fifth aspect of the present invention, in the printing apparatus according to the third or fourth aspect, the paper transport mechanism is provided in a paper discharge unit that transports print paper on which printing has been completed,
Since the pair of transport rollers are arranged so as to be in contact with the printing surface side of the printing paper, in addition to the effects of the invention according to claim 3 or 4, the pair of transport rollers are provided only at both ends of the printing surface of the printing paper. Since the rolls come into contact with each other, there is no possibility that the printing surface of the printing paper will be stained except for both ends.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention and is a schematic configuration diagram of an entire stencil printing apparatus.

FIG. 2 is a perspective view of a sheet discharging unit of a sheet discharging unit according to the embodiment of the present invention.

FIG. 3 illustrates one embodiment of the present invention, and is a schematic configuration diagram of a discharge unit of a discharge unit.

FIG. 4 is a front view of a pair of plate cylinder side regulating guides, showing one embodiment of the present invention.

FIG. 5 shows an embodiment of the present invention, and is an enlarged front view of a main part of a pair of plate cylinder side regulating guides.

FIG. 6 is a configuration diagram illustrating an embodiment of the present invention, as viewed from the front side of a paper transport mechanism.

FIG. 7 is a plan view showing an embodiment of the present invention and showing an arrangement of upper discharge rolls of a paper transport mechanism.

FIG. 8 is a schematic diagram illustrating an embodiment of the present invention and illustrating operations of sheet feeding, printing, and sheet discharging.

FIG. 9 is a schematic diagram illustrating an embodiment of the present invention and illustrating operations of paper feeding, printing, and paper discharging.

FIG. 10 is a schematic diagram illustrating an embodiment of the present invention and illustrating operations of paper feeding, printing, and paper discharging.

FIG. 11 is a schematic diagram illustrating an embodiment of the present invention and illustrating operations of sheet feeding, printing, and sheet discharging.

FIG. 12 is a schematic diagram illustrating an embodiment of the present invention and illustrating operations of paper feeding, printing, and paper discharging.

FIG. 13 is a schematic diagram illustrating an embodiment of the present invention and illustrating operations of paper feeding, printing, and paper discharging.

FIG. 14 is a schematic front view of a paper transport mechanism showing an embodiment of the present invention and showing a proper transport state in which an end portion of a printing paper is pressed between an upper discharge roller and a lower discharge roller.

FIG. 15 is a schematic front view of the sheet transport mechanism showing an embodiment of the present invention, and showing a state in which an end portion of a print sheet is detached from the upper discharge roll and is in contact with a conical surface of the upper discharge roll.

16A and 16B illustrate an embodiment of the present invention, and FIG. 16A is an enlarged front view of a main part in a state where an end portion of a print sheet is pressed between an upper discharge roller and a lower discharge roller, and FIG. FIG. 5 is an enlarged front view of a main part in a state where an end of the printing paper is detached from the upper discharge roll and is in contact with the conical surface of the upper discharge roll.

FIGS. 17A and 17B show an embodiment of the present invention, and FIG. 17A is an enlarged plan view of a main part in a state where the end of the printing paper is pressed between the upper discharge roller and the lower discharge roller; () Is an enlarged plan view of a main part in a state where the end of the printing paper is detached from the upper discharge roll and is in contact with the conical surface of the upper discharge roll.

FIG. 18 is a schematic configuration diagram of a paper transport mechanism of a conventional printing apparatus.

FIG. 19 is a plan view of a paper transport mechanism of a conventional printing apparatus.

FIG. 20A is an explanatory view showing a state in which a sheet of a sheet transport mechanism of a conventional printing apparatus is detached from a transport roll, and FIG. 20B is an explanatory view showing a correct sheet transport state of the sheet transport mechanism. .

[Explanation of symbols]

 Reference Signs List 1 stencil printing device (printing device) 6 paper discharge section 22 printing paper (paper) 32 paper transport mechanism 47 lower discharge roll (transport member) 50 upper discharge roll (transport member, transport roll) 50a circumferential surface 50b conical surface ( Inclined surface) 50c arel surface

Claims (5)

[Claims] 1. A sheet is interposed between conveying members arranged vertically and a conveying force is applied to the sheet by at least one of the conveying members to convey the sheet, and the conveying members arranged above and below are arranged. In a paper transport mechanism configured as a pair of transport rolls that contact at least one of both ends of the paper while rotating, the pair of transport rolls have a circumference of the same diameter whose outer peripheral surfaces have a width in the rotation axis direction. A sheet transport mechanism, comprising: a surface; and an inclined surface formed on a side where the pair of transport rolls face each other, and having a diameter gradually reduced in a direction in which the pair of transport rolls face each other. 2. The paper transport mechanism according to claim 1, wherein a radius between the circumferential surface and the inclined surface of each of the transport rolls is formed as a round surface. 3. A printing paper is transported by a paper transport mechanism. The paper transport mechanism interposes the printing paper between transport members arranged vertically and applies a transport force to the printing paper by at least one transport member. Conveying the printing paper by acting, at least one of the conveying members arranged above and below is configured as a pair of conveying rolls that come into contact with both ends of the printing paper while rotating, this pair of conveying rolls, A circumferential surface of the same diameter whose outer circumferential surface has a width in the rotation axis direction,
A printing apparatus, comprising: a pair of transport rolls formed on opposing sides, and an inclined surface whose diameter gradually decreases in the direction in which the pair of transport rolls face each other. 4. The printing apparatus according to claim 3, wherein a space between the circumferential surface and the inclined surface of each of the transport rolls is formed as a round surface. 5. The printing device according to claim 3, wherein the paper transport mechanism is provided in a paper discharge unit that transports the print paper on which printing has been completed, and the pair of transport rolls is configured to transport the print paper. A printing device, wherein the printing device is arranged so as to contact a printing surface side.