JP2697566B2 - Paper transport device for printing press - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper transport device for a printing press that performs printing using a platen roller.

[0002]

2. Description of the Related Art In general, as shown in FIG. 4, a platen roller 21 is brought into contact with a thermal head 17 and an ink ribbon 19 provided with a constant tension is applied to the thermal head 17 and the platen roller as shown in FIG. 21. Above the thermal head 17, a capstan roller 22 and a pinch roller 23 are in contact with each other, the paper 20 is sandwiched between the capstan roller 22 and the pinch roller 23, and the capstan roller 22 And is rotationally driven by a motor 13 via the motor.

[0003] With this configuration, the thermal head 17 and the platen roller 21 are separated from each other during standby. When the printing operation starts, the paper 20 is sent to the printing unit through the space between the thermal head 17 and the platen roller 21, and the leading end of the paper 20 is moved to the capstan roller 22.
And the pinch roller 23. Thermal head 1
7 is pressed against the platen roller, and the capstan roller 22 is rotated at a constant speed by the motor 13 to start printing. The ink ribbon 19 is sent from the supply side to the take-up side at the same speed as the paper 20 while maintaining the tension. The dye is transferred from the ink ribbon 19 to the paper 20 by the heat applied by the thermal head 17. Platen roller 21
Is pulled by the paper 20 and rotates at the same speed as the paper 20.
When printing is completed up to the rear end of the sheet 20, the thermal head 17 is separated from the platen roller 21. Next, motor 1
3 is reversed and the leading end of the paper 20 is
Is returned to the position between the pinch rollers 21 and printing of the second color and thereafter is performed. When the printing of the third or fourth color is completed,
The paper 20 is discharged from the printing unit.

[0004]

In the above-described conventional paper transport apparatus, the capstan roller 22 for holding paper is provided with a printing unit because of the structure in which printing is performed in an area between the platen roller 21 and the thermal head 17. In such a case, the printer is installed at a position away from the printer, so that a blank portion that cannot be printed is large. In addition, since a capstan roller 22 and a pinch roller 23 for feeding paper are provided in addition to the platen roller 21, the structure is complicated, and there is a drawback that the miniaturization of the apparatus is hindered.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above-mentioned conventional drawbacks, and an object of the present invention is to reduce a non-printable blank portion and to reduce the size of the apparatus by using a paper transport of a printing machine. It is to provide a device.

[0006]

In order to achieve this object, in a paper transport apparatus for a printing press according to the present invention, a platen roller has a hollow shape, and penetrates the platen roller from a hollow portion to a peripheral surface. A plurality of suction holes are provided radially, and a piston slidable in the suction hole is provided, and a piston drive shaft that is rotationally driven in the hollow portion of the platen roller and has the piston connected to the peripheral surface is provided, Is the rotation center of the piston drive shaft the rotation center of the platen roller?
Are eccentric to the opposite side of the printing section .

[0007]

According to the present invention, the rotation of the piston drive shaft causes the platen roller to rotate synchronously via the piston and the suction hole, and the rotation center between the piston drive shaft and the platen roller is decentered. With the rotation of the shaft, the piston sequentially withdraws from the peripheral surface of the platen roller through the suction hole, so that a negative pressure is generated in the suction hole, and the negative pressure causes the paper to be attracted to the peripheral surface of the platen roller, and the paper is transferred to the platen roller. Sent along with the rotation of.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a part of a paper transport device of a printing press according to the present invention.
Main part broken perspective view, and FIG. 2 is also cross-sectional view, FIG. 3 is a likewise cross-sectional side view. In these figures, the platen roller 2 has a cylindrical shape having a hollow portion 2a, and a rubber 3 is wound around an outer peripheral portion. At both ends of the platen roller 2, a pair of suction holes 2 b penetrating from the hollow portion 2 a toward the rubber 3 on the peripheral surface are radially formed at an equal angle. The separation distance between the suction holes 2b provided at both ends is formed smaller than the width of the sheet 20. 5
Is a flange fixed to both ends of the platen roller 2;
Is a bearing, and 7 is a platen frame on which a bearing 6 fixed to the apparatus is mounted.
Are rotatably supported on a platen frame 7 by bearings 6.

Reference numeral 9 denotes a piston drive shaft disposed in the hollow portion 2a of the platen roller 2 and rotatably supported by a bearing 10 of a piston frame 11 fixed to the apparatus. . A piston rod 1 extending radially is provided on the peripheral surface of the piston drive shaft 9.
2 are implanted, and a spherical piston 12a is provided at the tip. The rotation center line 1 of the piston drive shaft 9
5 is parallel to the rotation center line 14 of the platen roller 2 and is eccentric with respect to the rotation center line 14 by δ from the thermal head 17, and each piston 12a is provided with the suction hole 2b.
Is slidably fitted inside.

Next, the transport operation of the paper transport device having such a configuration will be described. When the piston drive shaft 9 is rotated clockwise in FIG. 2 by the drive of the motor 13, the platen roller 2 also rotates synchronously via the piston 12a, and when the piston 12a at the position of A reaches the position of B, The inside of the suction hole 2b retreats, so that a negative pressure is generated in the suction hole 2b, and the paper 20 starts to be attracted to the peripheral surface of the platen roller 2. This suction is performed at the position C, that is, the thermal head 17.
At the position corresponding to the heat-generating resistor 18 and gradually decreases toward the position D.

As described above, the platen roller 2 attracts the paper 20 and the platen roller 2 presses the thermal head 17 with the ink ribbon 19 interposed therebetween, thereby performing printing. Since the paper 20 is directly attracted to the platen roller 2, printing can be started when the leading end of the paper 20 reaches the position C. Further, printing can be continued until the rear end of the paper 20 reaches the position C, and printing can be performed from the front end to the rear end of the paper 20, and there is almost no blank area where printing is not possible. When the platen roller 2 is rotated counterclockwise, a negative pressure starts to be generated at the position D, so that the paper can be returned by suction.

[0012]

As described above, according to the present invention, the platen roller is made hollow, and a plurality of suction holes penetrating from the hollow portion to the peripheral surface are provided in the platen roller in a radial manner. Along with disposing a slidable piston, the piston is rotationally driven in the hollow portion of the platen roller,
A piston drive shaft to which the piston is connected is provided on the peripheral surface , and the rotation center of the piston drive shaft is
Since the piston is eccentric from the rotation center to the opposite side to the printing portion , the piston sequentially retreats from the peripheral surface of the platen roller with the rotation of the piston drive shaft, so that a negative pressure is generated in the suction hole. sheet by pressure is directly adsorbed on the peripheral surface of the platen roller, Therefore misalignment of the paper and the platen roller is reduced can be highly accurate sheet conveyance, yet it is possible to perform printing over most total surface of the paper. Also,
Since the sheet is directly conveyed by the platen roller, a conveying roller or the like is not required unlike the related art, so that the apparatus can be downsized.

[Brief description of the drawings]

FIG. 1 is a fragmentary perspective view of a part of a sheet conveying device of a printing press according to the present invention, which is cut away.

FIG. 2 is a cross-sectional view of a sheet conveying device of the printing press according to the present invention.

FIG. 3 is a side sectional view of a sheet conveying device of the printing press according to the present invention.

FIG. 4 is an overall perspective view of a paper transport device of a conventional printing press.

[Explanation of symbols]

 2 Platen roller 2a Hollow portion 2b Suction hole 9 Piston drive shaft 12a Piston 13 Motor 14 Platen roller rotation center line 15 Piston roller rotation center line 17 Thermal head 19 Ink ribbon 20 Paper

Claims (2)

(57) [Claims] 1. A printing machine for printing through a sheet between a printing section and a platen roller in contact with the printing section,
The platen roller has a hollow shape, a plurality of radially extending suction holes penetrating from the hollow portion to the peripheral surface are provided in the platen roller, and a piston slidable in the suction hole is provided. is rotated at the hollow portion, the piston drive shaft, wherein the piston is coupled to the circumferential surface is provided, and the center of rotation of the piston drive shaft Puratenro
A sheet conveying device for a printing press, wherein the sheet conveying device is eccentric from the rotation center of the roller to a side opposite to the printing section . 2. A paper transport device for a printing press according to claim 1, wherein said piston has a spherical shape.