JPH0312766Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field This invention relates to a switchback mechanism of a paper passing device in a double-sided copying machine or the like.

Prior Art Figure 1 shows a double-sided system in which the direction of the copying machine after single-sided copying is changed using a switchback mechanism in the middle of the paper path, and the paper is turned over so that the uncopied side faces up and the paper is fed to the transfer unit again. FIG. 1 is a schematic diagram showing an example of a copying machine.

In the figure, reference numeral 1 denotes a photoreceptor drum, on the charged surface of which a scanned image of an original on an unillustrated original document mounting section, which is projected through a scanning optical system, is sequentially formed, forming an electrostatic latent image. In the next developing section 2, the electrostatic latent image is developed with toner.

The toner image on the surface of the photoreceptor drum 1 is transferred by the transfer charger 3 to copy paper fed from the paper feed section 4a or 4b in synchronization with the rotation of the photoreceptor drum 1, and the transferred image is transferred to the next stage. The fixing process is performed by fixing rollers 5 and 6. The copy paper that has undergone the fixing process is sent to the discharge section 7. This discharge part 7 has a shaft 8
A gate plate 9 is pivotally attached to the gate plate 9, and the fed copy paper is rotated according to the rotational position of the gate plate 9.
The tray 10 is selectively distributed into a discharge passage 11 in which the tray 10 is disposed and another passage 12 in which a switchback mechanism is disposed.

In the switchback mechanism, copy paper introduced by a pair of paper introduction rollers 15 made up of rollers 13 and 14 is sent into a return path 16.
A pair of paper delivery rollers 18, which share the roller 14 of the pair of paper introduction rollers 15 and are made up of this roller 14 and another roller 17, receive the copy paper in the return path 16 from its introduction end side and copy it. The feeding direction of the paper is changed, and the paper is sent out to a return path 20 consisting of a conveyor belt under the guidance of a direction change guide plate 19, passes through a pair of rollers 21, and is again fed to the transfer section under the guidance of a paper reverse delivery guide plate 22. Ru.

In the transfer section, the image is transferred onto the uncopied side of the copy paper.
After double-sided copying, the copy paper is sent to the discharge section 7 via the fixing rollers 5 and 6, and is accumulated on the tray 10 via the discharge path 11 guided by the gate plate 9 whose rotational position has been changed.

In the double-sided copying machine, in order to smoothly return the copy paper in the switchback mechanism, it is necessary to transfer the copy paper sent into the return path 20 to the paper delivery roller pair 18 side. As a means, for example, as shown in FIG. 2, the shaft 23 is arranged near the terminal end of the return passage 16, and is spaced slightly narrower than the minimum width of the copy paper to be fed, so as to correspond to both sides of the copy paper. Paper push-back levers 24 are distributed and pivoted at different locations.
An effective mechanism is to apply a spring bias to the paper delivery roller pair 18 side and push the copy paper sent to the return path 16 back to the paper delivery roller pair 18 side.

However, the copy paper after the fixing process may curl in various ways depending on the environmental conditions, the thickness of the copy paper, the water content, and other conditions. When feeding the machine, the leading end of the copy paper is received by the paper push-back lever 24 and as the leading end progresses, the end of the leading end of the copy paper moves toward the paper feed roller pair as shown by the virtual line in FIG. 18 side, and the leading end of the copy paper tends to wrap around the roller 13, and folds and wrinkles occur when feeding the paper to the pair of paper delivery rollers 18. Ta.

Purpose Therefore, this invention provides a paper feeding device in which paper is introduced into a return passage by a paper introduction part arranged vertically in parallel with a paper delivery part, and the paper is sent from the introduction terminal side to a paper delivery passage by the paper delivery part. In the switchback mechanism, a pushing member is pivotally connected to a position immediately on the return path side of the paper introduction section by a shaft at least above the paper introduction path from the paper introduction section and hangs down to a position below at least the paper delivery section. The present invention is characterized in that the terminal end of the paper introduced into the return path is pushed toward the paper delivery section, thereby eliminating the above-mentioned inconvenience in the switch-back mechanism of the paper feeding device in double-sided copying, etc. It is an object of the present invention to provide a switchback mechanism for a paper passing device that can avoid this problem and smoothly reverse feed paper such as copy paper, and that has a simple structure.

Embodiment An embodiment of this invention will be described below based on FIG.

The switchback mechanism of this embodiment is applied to the paper feeding device of the above-mentioned double-sided copying machine shown in FIG. A paper presser lever 25 is arranged on the way from the paper introduction roller pair 15 to the return path 16, and pushes the paper presser lever 25 downward, that is, toward the paper delivery roller pair 18 side.

The paper presser lever 25 moves the pair of paper introduction rollers so that the fulcrum is above the copy paper passage section.
It is pivoted at one point near the roller 13 of No. 5, corresponding to the center of the width of the copy paper, with a shaft 26, and its free end side hangs down under its own weight to push the copy paper toward the pair of paper feed rollers 18. It is set up so that it can be used.

The rest of the structure is the same as that of the double-sided copying machine shown in FIG.

The reverse transfer of copy paper by this switchback mechanism is carried out as follows.

The copy paper that has been copied on one side and sent to the discharge section 7 via the fixing rollers 5 and 6 is guided by the gate plate 9, which is set to the rotational position shown by the solid line in FIG. 3, and is sent to the passage 12. The paper is then introduced into a return passage 16 by being sandwiched between a pair of paper introduction rollers 15 made up of rollers 13 and 14. At this time, due to the rigidity of the copy paper itself and the conveyance force of the pair of paper introducing rollers 15, the copy paper pushes aside the paper presser lever 25, which had been in a hanging position due to its own weight, as shown by the imaginary line and advances. On the other hand, as the copy paper is introduced into the return path 16, the starting end of the copy paper pushes the paper push-back lever 24, and the spring of the paper push-back lever 24 stores a restoring force in the clockwise direction. .

The introduction end of copy paper is paper introduction roller pair 15
At the same time, the copy paper is pushed down by the weight of the paper presser lever 25, and the copy paper in the return path 16 is pushed toward the paper delivery roller pair 18 by the restoring action of the paper push-back lever 24. The downward movement of the end of copy paper introduction is facilitated, and the end of introduction of copy paper is reliably moved to
accepted.

The paper feed direction is changed by the pair of paper feed rollers 18 and the copy paper is sent out.The copy paper is reversed under the guidance of the direction change guide plate 19, with the uncopied side facing up, and is fed again to the transfer section via the return path 20. be done.

If the paper presser lever 25 is heavy, it may cause the copy paper to curl, and it also acts to suppress the copy paper from jumping when it is introduced from the paper introducing roller pair 15 into the return path 16. Therefore, it is desirable to use a member that is as light as possible.

Effects of the invention According to this invention, the paper is pivotally mounted at a position immediately on the return passage 16 side of the paper introduction part 15 at least above the paper introduction path from the paper introduction part 15 and below at least the paper delivery part. The present invention is characterized in that a pushing member 25 that hangs down to a position is provided to push the terminal end of the paper introduced into the return path 16 toward the paper delivery section 18. The movable member 25 can be slightly swung from the hanging state to the side, or can be pushed lightly with almost no influence of its own weight, and the paper introduced from the paper introduction section 15 to the return path 16 can be returned from the paper introduction section 15. When the paper goes out a little into the passage 16, it comes into contact with the hanging pushing member 25 in a strong state, so even if the paper is a thin sheet with weak stiffness, it can be pushed away from the pushing member 25 while moving through the return passage. 16 will be introduced without difficulty. Further, when the paper passes through the paper introduction section 15, the rear end loses the support provided by the paper introduction section, and the pushing member 25
Even if the paper is thick and stiff, the pushing member 25 will return to the vertical state under its own weight and push the rear end of the paper away from the paper feeder 18. can also be pushed down to the lowest level.

Therefore, even if the paper is weak and thin, the pushing member 25
Even if the paper is stiff and thick, the rear end of the introduced paper can be reliably introduced into the return path without being affected by
5 side to the paper delivery section 18 side, and then move the paper from the return passage 16 to the paper delivery section 1.
8 can be sent smoothly and reliably. Moreover, it has a simple structure in which only one pushing member 25, which hangs down due to its own weight, is attached to the switchback passage, so it can be provided easily and inexpensively, and it can be highly reliable with few failures.

[Brief explanation of the drawing]

FIG. 1 is a schematic view of a double-sided copying machine having a switchback mechanism, FIG. 2 is a schematic view of a switchback mechanism having a paper push-back lever, and FIG. 3 is a schematic view of an embodiment of this invention. 12...Aisle, 13,14,17...Roller,
15...Pair of paper introduction rollers, 16...Return path, 18...Pair of paper delivery rollers, 19...
...Direction change guide plate, 20...Return passage, 24...
...Paper push-back lever, 25...Paper presser lever, 26...Shaft.

Claims (1)

[Scope of utility model registration request] The paper introduced into the return path 16 by the paper introducing section 15 arranged vertically in parallel with the paper discharging section 18 is passed through the paper discharging section 1 from the introduction terminal side.
In the switchback mechanism of the paper feeding device configured to feed the paper to the paper delivery path by 8, the switch is pivoted by a shaft 26 at a position immediately on the return path 16 side of the paper introduction part 15 at least above the paper introduction path from the paper introduction part 15. A pushing member 25 is provided that hangs down to a position below at least the paper delivery section, so that the terminal end of the paper introduced into the return path 16 can be pushed to the paper delivery section 1.
A switchback mechanism for a paper passing device, characterized in that it is pushed toward the 8th side.