JP2898206B2 - Stencil printing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device for a stencil printing machine.

[0002]

2. Description of the Related Art As shown in FIG. 4, a stencil printing machine comprises a stencil printing machine main body 60 and a table section 50. The sheets P stacked on the sheet feeding plate 54 of the sheet feeding tray 53 of the table unit 50 are separated one by one between the separation roller 51 and the separation pad 52, and the plurality of conveyance roller pairs 55 and the conveyance The sheet is sent to the registration roller pair 63 of the stencil printing machine main body 60 by the guide plate 58.

[0005] The transport roller pair 55 is constantly rotating, whereas the registration roller pair 63 is stopped when the leading edge of the paper P reaches it. To bend the sheet P.

On the other hand, in the stencil printing machine main body 60, a perforated image corresponding to a document is made on a master and wound around a plate cylinder 61, and ink is supplied from an inner peripheral surface of the plate cylinder 61 by ink supply means (not shown). I have. The paper P is conveyed between the plate cylinder 61 and the press roller 62 by the registration roller pair 63 at a predetermined timing, pressed by the press roller 62 by the master, and the ink is transferred to the paper P for printing. The printed paper P is suction-conveyed by the suction conveyance device 66 and is discharged to the discharge tray 67. Note that reference numeral 64
Represents a resist entrance guide plate.

[0005]

Generally, the linear velocity of the conveying roller pair and the plate cylinder of the conventional stencil printing machine described above is higher than the linear velocity of the conveying roller of the copying machine which is about 600 mm / sec. , 1200 mm / sec, which is a very high speed, so that the impact sound when the paper P sent by the conveying roller pair collides with the stopped registration roller pair 63 is quite loud.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an inexpensive stencil printing machine capable of reducing the impact noise of a sheet.

[0007]

According to the first aspect of the present invention,
A plate cylinder that rotates in a fixed direction, a feeding unit that feeds the paper stacked on the paper feed tray at substantially the same linear speed as the plate cylinder, and a sheet fed by the feeding unit. In a stencil printing machine including a pair of registration rollers that are conveyed to the cylinder at a predetermined timing, a pair of reduction rollers arranged between the pair of registration rollers and the feeding unit, and the sheet is fed by the feeding unit. After being conveyed and reaching the pair of reduction rollers, the pair of reduction rollers is rotated while being decelerated to cause the sheet to reach the pair of registration rollers, and after the sheet reaches the pair of registration rollers, The image forming apparatus further includes a reduction roller driving means for causing the rotation speed to follow the sheet conveyance speed of the pair of registration rollers.

According to a second aspect of the present invention, in the stencil printing machine according to the first aspect, one of the rollers of the pair of reduction rollers is provided with a one-way rotary clutch that transmits a driving force only in the sheet conveying direction. , Provided on its drive shaft,
A cam that rotates in synchronization with a printing cycle of one sheet by the plate cylinder, a sector gear that swings by the cam, and a gear that meshes with the sector gear and rotates the drive shaft. And characterized in that:

According to a third aspect of the present invention, there is provided a plate cylinder rotating in a fixed direction, feeding means for feeding sheets stacked on a sheet feed tray at substantially the same speed as the linear speed of the plate cylinder, and A stencil printing machine including a pair of registration rollers for conveying the paper fed by the feeding means to the plate cylinder at a predetermined timing;
A roller provided on a drive shaft and a roller driven by the roller via a one-way rotating clutch disposed between the registration roller pair and the feeding means and transmitting a driving force only in the sheet conveying direction. , A cam rotating in synchronism with the printing cycle of one sheet by the plate cylinder, a sector gear oscillated by the cam, and the drive shaft meshing with the sector gear and moving the drive shaft in the one direction. And a reduction gear driving means having a gear rotating via a rotary clutch. After the paper is conveyed by the feeding means and reaches the reduction gear pair, the reduction gear driving means is driven by the reduction roller driving means. To cause the paper to reach the registration roller pair, and after the paper reaches the registration roller pair, reduce the rotation speed of the reduction roller pair to Characterized in that to follow the sheet conveying speed of Jisutorora pairs.

[0010]

According to the first aspect of the present invention, the sheets stacked on the sheet feed tray are fed to the speed reduction roller pair by the feeding means. After the paper reaches the pair of reduction rollers, the driving means causes the paper to reach the pair of registration rollers while decelerating the pair of reduction rollers.

According to the second aspect of the present invention, the sheets stacked on the sheet feed tray are fed to the speed reduction roller pair by the feeding means. A cam that rotates in synchronization with a printing cycle of one sheet by the plate cylinder after the sheet arrives at the reduction roller pair;
The sheet arrives at the registration roller pair while the speed reduction roller pair is decelerated by the sector gear swinging in conjunction with the cam.

According to the third aspect of the present invention, the sheets stacked on the sheet feed tray are fed to the speed reduction roller pair by the feeding means at a feeding speed equal to the linear speed of the plate cylinder. After the leading end of the sheet reaches the pair of deceleration rollers, the driving means decelerates the pair of deceleration rollers to decelerate only the leading end of the sheet so that the sheet reaches the pair of registration rollers.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a stencil printer main body, and reference numeral 2 denotes a table unit 2 in which a plurality of paper feed trays 23 on which sheets P are stacked are stored.

The stencil printer main body 1 is a stencil printer 1 on which a master on which a perforated image corresponding to a document is written is wound around the outer peripheral surface.
1, an ink supply means (not shown) for supplying ink to the inner peripheral surface of the plate cylinder 11, a press roller 12 for pressing the sheet P against the plate cylinder 11, and a predetermined timing between the press roller 12 and the plate cylinder 11. A pair of registration rollers 13 for transporting the sheet P, a pair of reduction rollers 31 for reducing the transport speed of the sheet P transported to the pair of registration rollers 13, and a pair of reduction rollers 3
2, a feed roller pair 19 for feeding the sheet P conveyed from the table unit 2 to the reduction roller pair 31, and separating the printed sheet P from the outer peripheral surface of the plate cylinder 11. , A suction transport device 16 for transporting, and a discharge tray 1 on which the paper P transported by the suction transport device 16 is stacked
It becomes the main from seven.

Reference numeral 14 denotes a resist entrance guide plate. The registration entrance guide plate 14 is curved upward between the registration roller pair 13 and the reduction roller pair 31 so as to allow the sheet P to bend, as shown in FIG.

The table unit 2 includes a plurality of paper feed trays 23 arranged vertically, a paper feed raising plate 24 provided inside each of the paper feed trays 23 for loading paper P, and It mainly comprises a feeding means for feeding the stacked sheets P.

The paper feed raising plate 24 is raised by a vertical movement mechanism (not shown) so that the upper surface of the paper P comes into contact with the paper feed rollers 21.

The feeding means includes a paper feed roller 21 disposed on one upper portion of the paper feed tray 23, a separation pad 22 for separating the paper P one by one, and a guide plate 25 for guiding the paper P.
And a transport roller pair 15 for transporting the paper P.

The plate cylinder 11, the paper feed roller 21, the transport roller pair 15, and the feed roller pair 19 are set at the same linear speed.

As shown in FIG. 2, the driving means 40 includes a cam 41 which rotates in synchronization with a printing cycle of one sheet P by the plate cylinder 11 and a sector gear 43 which swings in conjunction with the cam 41. And one of the speed reduction rollers 3
And a drive gear 48 provided at an end of one drive shaft 49. Inside the drive gear 48, the paper P
The one-way rotary clutch for transmitting the driving force only in the transport direction (indicated by the arrow Y in the figure) is press-fitted.

The cam 41 is connected to the side plate 39 of the stencil printing machine main body 1.
And is rotatably driven by a motor (not shown).

The sector gear 43 has a substantially rectangular shape and has a bearing 44 a mounted on a shaft 44 fixed to the side plate 39.
It is swingably supported via. Sector gear 43
A gear portion 43a is formed at one end of the base plate, and a pin is provided at the other end.
A tension spring 47 is stretched between the pin 39a and the pin 39a. The roller 45 rotatably supported on a shaft 46 provided on the sector gear 43 by the urging force of the tension spring 47 is in pressure contact with the outer peripheral edge 41 a of the cam 41.

The above-described one-way rotating clutch is a known spring clutch. When the driving gear 48 rotates in the transport direction of the paper P, the rotation of the driving gear 48 is transmitted to the driving shaft 49, and the driving gear 48 The rotation of the drive gear 48 is not transmitted to the drive shaft 49 when rotated in the direction opposite to the conveyance direction of the drive gear 49.

The rotation of the cam 41 causes the sector gear 43
Is rotated about the shaft 44 to rotate the drive gear 48 forward and backward once in the printing cycle of one sheet P by the plate cylinder 11. The forward / reverse rotation of the drive gear 48 also allows the reduction roller pair 31
Does not rotate in the direction opposite to the transport direction of the paper P.

The linear velocity of the pair of reduction rollers 31 changes during the printing cycle of one sheet of paper P by the plate cylinder 11;
FIG. 3 shows the linear velocity characteristics of the reduction roller pair 31. In the figure, the horizontal axis represents time, and the vertical axis represents linear velocity.

The point A shown in FIG.
The point B represents the time at which the leading end of the sheet P has arrived, the point B represents the time at which the leading end of the sheet P has reached the registration roller pair 13, and the point C represents the time at which the registration roller pair 13 has started rotating.

The linear velocity of the pair of reduction rollers 31 is the same as the linear velocity of the plate cylinder 11 at the point A (hereinafter, referred to as the main velocity). Then, the reduction roller pair 3
1 follows the paper P and rapidly increases to the main speed.

The shape of the outer peripheral edge 41a of the cam 41 is as follows.
It is determined based on the linear velocity characteristics of the reduction roller pair 31 shown in FIG. Therefore, the leading end of the paper P is
When 1 is in the decelerating state, it reaches the registration roller pair 13.

When the speed reduction roller pair 31 is in a deceleration state, a linear speed difference occurs between the speed reduction roller pair 31 and the feed roller pair 19, and the paper P is bent. In order to prevent the paper P from being jammed or broken by releasing the bending, a new conveyance guide plate 32 having a shape for releasing the bending generated in the paper P is disposed between the speed reduction roller pair 31 and the feed roller pair 19. ing.

Next, the operation of the stencil printing machine will be described. First, when the paper P is stacked on the paper feed raising plate 24 of the paper feed tray 23 and the paper feed tray 23 is arranged at a predetermined position of the table unit 2, the paper feed tray 23 is moved up and down by a vertical movement mechanism (not shown). The plate 24 rises and the upper surface of the sheet P comes into contact with the paper feed rollers 21, and the elevation of the paper feed raising plate 24 stops at a position where the pressure on the paper feed rollers 21 reaches a predetermined pressure.

The above-described operation is similarly performed inside each paper feed tray 23, and the paper P is set on each paper feed raising plate 24. When a start key (not shown) is pressed, the paper feed roller 21 of the paper feed tray 23 on which the paper P corresponding to the image size is loaded starts to rotate at the same linear speed as the plate cylinder 11. P is fed toward the guide plate 25 and separated one by one between the separation pad 22 and the feed roller 21.
Is conveyed toward the feed roller pair 19 inside. On the other hand, the cam 41 of the driving means 40 starts rotating at the same time as the rotation of the paper feed roller 21, and the roller 4 pressed against the outer peripheral edge 41 a is pressed.
5 by pressing the sector gear 43 around the shaft 44,
It swings in the direction of arrow X shown in FIG. As a result, the drive gear 48 meshing with the gear portion 43a of the sector gear 43 is rotated, and the reduction roller pair 31 is rotated via the one-way rotation clutch described above.

The leading end of the sheet P is moved by the feed roller pair 19 along the new transport guide plate 32 to the speed reduction roller pair 31.
(Point A in FIG. 3). After a lapse of a predetermined time, the speed reduction roller pair 31 starts to be decelerated. In this deceleration state, the leading end of the paper P slowly collides with the registration roller pair 13 (indicated by a point B in FIG. 3). Even after the leading edge of the paper P collides with the registration roller pair 13, the feed roller pair 19, the transport roller pair 15, and the paper feed roller 21 continue to rotate at the main speed, and the paper P is bent as shown in FIG. Is done. Therefore, here, only the leading end of the sheet P is decelerated, and the trailing end is conveyed by any of the sheet feeding roller 21, the conveying roller pair 15, and the feed roller pair 19.
The paper feed roller 21, the transport roller pair 15, and the feed roller pair 19 stop sequentially after the rear end of the paper P has passed.

Thereafter, after a lapse of a predetermined time, the registration roller pair 13 starts to rotate at the main speed (indicated by a point C in FIG. 3), and the sheet P is wound by a perforated master made in accordance with the image information of the document. The paper P is conveyed between the outer peripheral surface of the mounted plate cylinder 11 and the press roller 12, the paper P is pressed against the master by the press roller 12, and ink is formed in the master from the inner peripheral surface of the plate cylinder 11. Is transferred to the surface of the paper P to form a print image.

Here, the pair of speed reduction rollers 31 rotates together with the sheet P conveyed by the pair of registration rollers 13 and rapidly increases the linear velocity, so that the bending of the sheet P disappears.

The paper P on which the print image has been formed is thereafter
The sheet is separated from the outer peripheral surface of the plate cylinder 11 by the suction conveyance device 16, discharged to the discharge tray 17, and the first printing is performed for test printing (with printing).

In this embodiment, the driving means 40 is connected to the cam 41
However, the configuration using the stepping motor may be used.

By adjusting the outer peripheral shape of the cam 41 and the phase of the home position between the cam 41 and the plate cylinder 11, the line of the pair of reduction rollers 31 in the printing cycle of one sheet P by the plate cylinder 11 is adjusted. Speed change can be set freely.

[0038]

According to the first aspect of the present invention, after the paper reaches the speed reduction roller pair, the driving means causes the paper to reach the registration roller pair while decelerating the speed reduction roller pair. A stencil printing machine capable of suppressing an impact sound when a collision occurs.

According to the second aspect of the present invention, the speed reduction roller pair is decelerated by the cam rotating in synchronization with the printing cycle of one sheet by the plate cylinder and the sector gear swinging in conjunction with the cam. Since the sheet is made to reach the registration roller pair while the sheet is being made, it is possible to suppress an impact sound when the sheet collides with the registration roller pair, and to provide a stencil printing machine with low cost.

According to the third aspect of the present invention, in addition to the effect of the first or second aspect, after the leading end of the sheet reaches the pair of reduction rollers, the driving means decelerates the pair of reduction rollers to cause the leading end of the sheet. Only the speed is reduced so that the sheet reaches the registration roller pair, so that the printing speed does not decrease.

[Brief description of the drawings]

FIG. 1 is a front view of a stencil printing machine showing one embodiment of the present invention.

FIG. 2 is a perspective view showing a driving unit of the stencil printing machine shown in FIG.

FIG. 3 is a graph showing a linear velocity characteristic of the reduction roller pair shown in FIG.

FIG. 4 is a schematic front view of a conventional stencil printing machine.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 stencil printer main body 2 table section 11 plate cylinder 12 press roller 13 registration roller pair 14 registration entrance guide plate 15 transport roller pair 16 suction transport device 17 paper discharge tray 21 paper feed roller 22 separation pad 23 paper feed tray 24 paper feed rise Plate 31 Reduction roller pair 32 New conveyance guide plate 40 Drive means 41 Cam 43 Sector gear 44 Axis 48 Drive gear 49 Drive axis P Paper

Claims (3)

(57) [Claims] 1. A plate cylinder rotating in a fixed direction, feeding means for feeding paper stacked on a paper feed tray at substantially the same linear speed as the plate cylinder, and paper fed by the feeding means. A stencil printing machine comprising a pair of registration rollers for conveying the sheet to the plate cylinder at a predetermined timing, and a pair of reduction rollers disposed between the pair of registration rollers and the feeding means; After being conveyed by the feeding means and reaching the deceleration roller pair, the deceleration roller pair is rotated while being decelerated to cause the paper to reach the registration roller pair,
A stencil printing machine comprising a reduction roller driving means for causing the rotation speed of the reduction roller pair to follow the paper transport speed of the registration roller pair after the paper reaches the registration roller pair. 2. One of the rollers of the speed reduction roller pair is provided on a drive shaft thereof via a one-way rotating clutch that transmits a driving force only in the sheet conveyance direction. And a cam that rotates in synchronization with a printing cycle of one sheet by the plate cylinder, a sector gear that is swung by the cam, and a gear that meshes with the sector gear and rotates the drive shaft. A stencil printing machine according to 1. 3. A plate cylinder rotating in a fixed direction, feeding means for feeding sheets stacked on a sheet feeding tray at substantially the same speed as the linear speed of the plate cylinder, and paper fed by the feeding means. A stencil printing machine including a pair of registration rollers for conveying the sheet to the plate cylinder at a predetermined timing, wherein the driving force is disposed only between the pair of registration rollers and the feeding means, and only in a direction in which the sheet is conveyed. Through a one-way rotating clutch that transmits
A speed reduction roller pair including a roller provided on a drive shaft and a roller driven by the roller; a cam rotating in synchronization with a printing cycle of one sheet by the plate cylinder; and a sector gear swinging by the cam. And a reduction gear driving means having a gear meshing with the sector gear and rotating the drive shaft via the one-way rotation clutch.The paper is conveyed by the feeding means and the reduction roller pair After the arrival, the deceleration roller pair is decelerated and rotated by the deceleration roller driving means to cause the paper to reach the registration roller pair.After the paper reaches the registration roller pair, the rotation speed of the reduction roller pair is reduced. A stencil printing machine for following the paper transport speed of the pair of registration rollers.