JPS604463B2 - printing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing device, and more particularly, to a printing device that transfers a toner image formed on a recording drum onto folded paper.

In a type of device such as an electrostatic or Kasushi printing device that performs printing by transferring a toner image formed on a recording drum onto a sheet of paper, a folded paper 1 as shown in FIG. 1 is used. Widely used.

As is well known, this type of folded paper is folded with the front side and the hair folded alternately. Crease l as shown
Corresponding to a, lb, lc, . . . , mountain-fold portions indicated by the symbol a and valley-fold locations indicated by the symbol b appear alternately. Therefore, as shown in FIG. 3, in order to transfer the toner image 3 formed on the outer circumferential surface 2a of the recording drum 2 onto the paper 1, the paper 1 is moved by the paper feed tractor 4 and the guide 5. When feeding in the direction of arrow B at a speed equal to the circumferential speed of the recording drum 2 in the direction of arrow A and in contact with the outer circumferential surface 2a of the recording drum 2, the fourth As shown in Figures a and b', the paper 1 does not come into close contact with the outer peripheral surface 2a of the recording drum 2 and floats up. Therefore, as shown in FIG. 3, a corona charge is applied to the paper 1 from the back side of the paper 1 by the transfer corotron 6, the toner image 3 on the recording drum 2 is transferred to the paper 1, and the toner image 3 on the recording drum 2 is transferred to the paper 1.
When the transfer device 3' is formed on the paper 1, there is a drawback that the transferred image 3' becomes unclear at the folded portion of the paper 1. Therefore,
Conventionally, in order to correct this crease, a leaf spring member 7 is provided as shown in FIG.
Tension was applied in the direction shown by arrow C.

However, in order to increase the effect of the fold correction means using the plate spring member 7, if the spring force is increased, the paper will tend to tear, whereas if the spring force is weakened, the effect of correcting the folds will be weakened. Therefore, it is necessary to adjust the leaf spring member 7 so that an appropriate spring force is applied to the paper 1, and to maintain the appropriate spring force. However, it is extremely difficult to maintain a constant tension during the operation period with such adjustment, and with this type of crease correction mechanism, the transferred image may become unclear due to insufficient tension, or it may become slightly blurred due to excessive tension. This has the disadvantage that the paper is damaged. An object of the present invention is to provide a printing device that can stably and reliably correct the folds of folded paper and obtain a good transferred image.

The features of the present invention for achieving the above object include a recording drum for forming a toner image, a transfer device for transferring the toner image onto folded paper, and a transfer device for transferring the folded paper in synchronization with the rotation of the recording drum. In a printing device equipped with a paper feeding device that feeds the paper to the transfer device in a related manner, a plurality of roller groups supported in parallel at predetermined intervals on a common frame are disposed facing each other, and a spring is applied to attract each other to the rollers. The group includes a fold correction means arranged so as to press the folded paper from both the front and back sides and pass the folded paper in close contact with the roller surface in a meandering state, and the folded paper is corrected by the tensile force of the paper feeding device. After passing through the means, it is supplied to the transfer device.

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments. FIG. 5 schematically shows an embodiment of an electrostatic printing device according to the invention.

The electrostatic printing device 10 includes a recording drum 12 on the circumferential surface of which a toner image is formed, and the drum 12 is rotated at a constant speed in the arrow x direction by a rotation drive device (not shown).
A folded paper 11 for transferring a toner image formed on the surface 12a of the drum 12 is stored in a predetermined crab 13, and this folded paper 11 is moved between a guide 15 and a transfer corotron 16 by a paper feed tractor 4. The toner image is transferred to the folded paper 11 by applying a corona charge by the transfer controller 16. After the transfer is completed, the folded paper 11 is fed to a fixing device (not shown) by a paper feed tractor 14. In the printing apparatus, a crease correction device 20 is provided between the sparrow 13 and the paper feed tractor 4 in order to correct the creases in the mountain folds and valley folds that occur in the folds of the folded paper 11. FIG. 6 shows the crease straightening device 20 shown in FIG.

The fold straightening device 20 includes five rollers 21 to 25, and the rollers 21, 23, 25 are connected to a pair of connecting rods 26, 26.
' (only one of which is shown in the drawing). On the other hand, the rollers 22, 24 are rotatably supported by another pair of connecting rods 27, 27' (only one of which is shown in the drawing), and the corresponding connecting rods 26, 27 are supported by coil springs 28, 27'. A spring force is applied by 29 to attract each other. The other corresponding connecting camphor 26', 27 not shown in FIG.
' is also constructed in the same way. The rollers supported by each of the continuous logs 26 and 27 are supported by bearings at a predetermined interval, and the roller 22 is in contact with both the rollers 21 and 23, and the roller 24 is in contact with the rollers 23 and 25. It is arranged so that it contacts both sides. As shown in FIG. 6, the folded paper 11 is passed between the rollers so as to pass through the pressure acid parts p, q, r, and s of each roller, and then the paper feed tractor 4
is pulled out in the direction of arrow Y. These rollers 2
1 to 25 are pressed against each other by coil springs 28 and 29, so that the folded paper 11 is pressed by the rollers from the front and back sides, and the folded paper 11 is moved in a meandering trajectory to the device 20.
pass through the inside. As a result, the mountain folds a and valley folds b that have occurred in the folded paper 11 are removed by applying pressure P to both sides of the folded paper 11 by the rollers 21 and 22, as shown in FIGS. 7a and 7b, for example.
, P2, and when the fold part (the mountain fold part in the illustrated example) a passes through the pressure saddle part P, the arrows Q,, Q2
A force as shown in is applied to the folded portion, and the mountain fold a is flattened at the compression part p.

Exactly the same operation is performed on the other pressure parts, and the mountain folds or valley folds are flattened. In addition, when the folded paper 11 passes through the pressing parts p, q, r, and s, these folds a and b provide resistance to the tensile force of the paper feed tractor 14, and the tension applied to the folded paper 11 is reduced. increases to flatten the crease.

In this way, the folds are corrected not only by simply applying tension to the folds, but also by applying pressure force to the folds by the rollers, so that the folds can be reliably corrected without damaging the folded paper. Therefore, when the folded portion enters the transfer device 17, the folded portion is completely corrected, so that the folded portion does not float off the surface of the recording drum 12, and is in close contact with the surface.

Therefore, good transfer can be performed. In the above embodiment, the present invention was applied to an electrostatic printing device, but the present invention can also be applied to other types of printing devices that use folded paper.

Further, the folded state of the folded paper is not limited to that shown in FIG. 1, and may be folded by any folding method. Furthermore, although the number of rollers in the crease straightening device of the embodiment is five, the number of rollers is not limited to five;
A plurality of them may be provided as appropriate. However, if the paper has mountain folds and valley folds as in the illustrated example,
Preferably, at least three rollers are provided so that the paper can be bent in a direction opposite to the folding direction of each fold. According to the present invention, as described above, folds in folded paper can be reliably corrected without damaging the paper.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the folded paper, FIGS. 2a and 2b are plan views and side views of the folded paper shown in FIG. A schematic diagram of the main parts of the printing device, FIGS. 4a and 4b are diagrams showing the state of contact between the recording drum and the folded paper when the folds of the folded paper are not corrected, and FIG. 5 is an embodiment of the present invention. 6 is a detailed front view of the crease correction device shown in FIG. 5, and FIGS. 7a and 7b are operation explanatory diagrams for explaining the operation of the device shown in FIG. 6. 10: Electrostatic printing device, 11: Shinpo paper, 12: Recording drum, 12a: Surface, 14: Paper feed tractor, 15: Guide, 16: Transfer corotron, 17: Transfer device, 20: Crease correction device, 21 to 25: roller, a: mountain fold, b
: Valley fold. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] 1. A recording drum for forming a toner image, a transfer device for transferring the toner image onto folded paper, and a paper feeding device for feeding the folded paper to the transfer device in synchronization with rotation of the recording drum. In a printing device equipped with a common frame, a plurality of roller groups supported in parallel at predetermined intervals are disposed facing each other, applying spring force that attracts each other, and the roller groups press the folded paper from both the front and back sides. and a fold correcting means arranged so as to pass the folded paper in close contact with the roller surface in a meandering state, and the folded paper is supplied to the transfer device after passing through the fold correcting means by the tensile force of the paper feeding device. A printing device characterized by: