JPS6017776A - Sheet separating device - Google Patents

Abstract

PURPOSE:To form a sheet separating device which generates no image distortion without making a device large-sized or without narrowing the effective width of a photosensitive body by constituting at least a part of a deflecting roller of the side spacing a separating roller to obtains a larger diameter than that of the separating roller. CONSTITUTION:The deflecting roller 8 is formed to obtain a large diameter as it is spaced further a separating roller 7. In case of separating a sheet by using such the deflecting roller, even if the sheet 8 is carried in a rise state, the part of the deflecting roller 8 of the part where the rise of the sheet is large also rises with a large curvature, to maintain the contact the deflecting roller. Accordingly, the sheet 8 is fed to keep along a guide plate 5 as it is as a whole. Thus an image is transferred on the sheet to eliminate the distortion.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a sheet separating device for a copying machine after transfer, and more particularly to a sheet separating device including a separating belt, a separating roller, and a deflecting roller.

Prior Art An elongated belt-like separator is arranged along one end aK of the photoreceptor so that the side edge of the sheet moves over it, and this
A sheet separating device Fi that separates sheets more easily;
This is known from Japanese Patent Application Laid-Open No. Sho Sθ-K9θ Dada.

This sheet separation device IT is preferable because it eliminates the need for electrostatic separation or pneumatic separation, but it has the drawback that the peeling force during separation is weak @ JP-A-Sho! f;/-Kgko No. 33 provides a separation belt along the side edge of the photoconductor, and also includes a separation roller that applies a strong peeling force to the sheet on the belt, and a deflection roller that changes the posture of the sheet after separation. A sheet separating device is disclosed. This sheet separation device is preferable because it has sufficient peeling force, but since the peeling force is different between the side with the separation roll and the side without the separation roll, there is a slight speed difference in the transfer area, which causes problems after transfer. The problem was that the image was distorted.

These problems will be explained with reference to FIGS. 1 to 3, which show devices that have already been proposed but are not included in the above-mentioned publication. A transfer corona discharger 2 is provided in the transfer area of the photoreceptor 1, and the sheet 8 is fed so as to come into contact with the photoreceptor 1 in this transfer area, and the sheet 8 after transfer is transferred to the sheet separation device 4. It is separated and sent to the guide plate 5, where it is fixed. The sheet separating device 4 contacts a separating belt 6 arranged so that the side edge of the sheet 8 moves along one end edge of the photoconductor 1 and the side edge of the sheet 8 on the belt, and separates the sheet 8 from the separating belt 6 . A separating roller 7 rotates to separate the photoreceptor 1 from the photoreceptor 1, and a separating roller 7 is placed coaxially in parallel with this roller 7 and rotates together with the roller.

A pin roller 9 is arranged opposite to the separation roller 7, and a guide pin 10 is provided to deflect the belt 6 so as to press it against the separation roller 7. It is being

FIG. 2 shows how sheets 3 are separated using such a sheet separating device. As can be seen from this figure,
) The sheet 8 separated by the Miyabi roller ruff is advanced at the end on the separation roller 7 side and is advanced along the separation roller ruff, but as it moves away from the separation roller 7, the peeling force of the sheet decreases. The advancing speed of the sheet is delayed, albeit slightly, and the leading edge of the sheet rises as shown by the solid line.

Of course, if the sheet is advanced further, the sheet will be able to advance along the deflection roll 8 as shown by the dashed line a.
While the leading edge of the sheet is rising, the sheet is displaced, causing transfer displacement in the transfer area and distorting the image. This image distortion is caused by the fact that the diameters a and b of both rollers are the same as shown in Figure 3, and the feed force from the roller 28 is not sufficient and the feed speed is slightly slower than that of the separation roller. However, the cause of this is that the separation point of the sheet is different between the sheet side edge on the separation belt side and the sheet side line on the opposite side, and there is no means to quickly make the sheet follow the guide plate. In order to eliminate this drawback, some systems have increased the contact width of the separation belt with the paper, but if the effective width of the photoreceptor becomes narrower, or if the effective width of the photoreceptor is widened, the device becomes larger. Separately, there are also methods that reduce the deflection angle when separating sheets, but this increases the space occupied by the sheet feeding path and makes the device larger. Therefore, an object of the present invention is to provide a sheet separation device that does not cause image distortion without increasing the size of the device or narrowing the effective width of the photoreceptor. SUMMARY OF THE INVENTION To achieve the above object, a sheet separating device according to the present invention provides a sheet separating device in which at least a part of the separating roller on the side remote from the separating roller has a diameter larger than that of the separating roller. is being used.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings. FIG. 9 shows an embodiment according to the present invention,
For convenience of explanation, some members are omitted. I am strong,
As shown in FIGS. 1 and 2, the sheet separating device according to the present invention basically includes a separating roller 7, a deflecting roller 8, and a separating belt 6, and also includes a pinch roller 9 and a separating belt 6. A guide pin 10 is additionally provided.

In one embodiment of the invention, the deflecting roller 8 is formed such that its diameter increases as it moves away from the separating roller ruff. That is, the diameter of the deflection roller 8 on the separation roller side is equal to the diameter arc of the separation roller 7, but the diameter C on the opposite side is larger than the diameter 8 of the separation roller. Figure @5 shows a deflection roller 8 having another shape, and in this example, a portion including the end opposite to the separation roller 7 has a diameter C, which is larger than the diameter a of the separation roller 7. Further, if the degree of increase in the diameter of the deflection roller 8 is small, the deflection roller 8 as a whole may be enlarged as shown by the imaginary line in FIG.

When separating sheets using such a deflecting roller, even if the sheet 8 is conveyed in an upright state as shown in FIG. Since the portion of the deflection roller 8 on the opposite side also rises with a large curvature, the sheet maintains contact with the deflection roller, and therefore the sheet 8 as a whole is fed as it is along the guide plate 5Vc. Moreover, as can be seen in FIG. The sheet begins to be separated from the photoreceptor due to the peeling force applied earlier at the large diameter portion of the deflection roller 8 than at the side edge of the deflection belt, and as a result, the sheet is pressed against the guide plate 5 earlier than at the side edge on the separation belt side. I can do it. Furthermore, since the diameter of the deflection roller is larger than the diameter of the separation roller, the surface speed of the deflection roller increases, and the sheet quickly reaches the state shown by the two-dot chain line in FIG.

Therefore, it can be seen that the distortion is substantially eliminated after the image is transferred onto the sheet.

Effects of the Invention According to the present invention, it is possible to separate sheets without causing image distortion during one transfer without increasing the width of the separation belt or regulating the deflection angle of the sheet to be small. ,
Since the structure is extremely simple, it is difficult to increase the price of the device, and since the posture of the sheet after transfer is maintained properly, the running posture of the sheet after transfer is appropriate, and the fuser etc. It does not cause wrinkles.

[Brief explanation of the drawing]

Figure 2 is a side view of a conventional sheet separation device, Figure 2 is a perspective view of a conventional sheet separation device, Figure 3 is a plan view showing the relationship between the separation roller, deflection roller, and photoreceptor, and Figure 3 is a side view of a conventional sheet separation device. FIG. 3 is a perspective view of a sheet separating device according to an embodiment of the present invention, and FIG. 3 is a plan view similar to FIG. 3 showing another deflection roller shape according to the present invention. l...Photoreceptor, 2...Transfer corona discharger, 8...
Seat, 6...separation belt,? ...Separation roller, 8
... Deflection roller % 9 ... Pinch roller.

Claims (1)

[Claims] To separate the sheets downstream of the transfer area, a separation belt is provided along one edge of the photoreceptor so that the sheet moves over it, and a separation belt that contacts the side line of the sheet on the belt to remove the sheet from the photoreceptor. a separation roller that rotates to separate the
In a sheet separating device comprising a deflecting roller coaxially arranged in parallel with the separating roller and regulating the posture of the sheet in a portion other than the heat dividing roller, at least a portion of the deflecting roller away from the separating roller is arranged in parallel with the separating roller. A sheet separating device characterized by being formed with a large diameter.