JPS5936742B2 - Copy machine safety device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, when a sheet to be fixed whose leading end is gripped by a sheet gripper comes off from the sheet gripper, or when it is not gripped from the beginning,
The present invention relates to a safety device for a copying machine that prevents the sheet to be fixed from entering a fixing device.

By the way, FIG. 1 shows an example of a copying machine, specifically a transfer type electrophotographic copying machine.

That is, in the figure, reference numeral 1 indicates a photosensitive drum that rotates in a sailor's direction. Around the photoreceptor drum 1, there is a charging device 2, an exposure optical system 4 that transmits an image of a document (not shown) placed on the document table 3 to the circumferential surface of the photoreceptor drum 1, and this optical system. A developing device 5 that visualizes the electrostatic latent image formed by the system, and a transfer charger 6 that assists in the transfer action.
, and a static eliminator 7 for removing residual charges on the drum surface. When a print button (not shown) is pressed, the photosensitive drum 1 rotates in a sailor's direction, and as it rotates, the charging device 2 charges the surface of the drum 1.

The document table 3 moves in the direction of arrow a in synchronization with the rotation of the photoconductor drum 1, and an electrostatic latent image corresponding to the image of the document (not shown) placed on the document table 3 is formed on the surface of the drum 1. , are formed via the exposure optical system 4. Further, this electrostatic latent image is visualized by the developing device 5. Here, in the figure,
The uppermost sheet S of the transfer sheets stacked on the paper feed table 8 is fed by the paper feed roller 9, and the leading edge of the sheet S further fed by a pair of paper feed rollers 11 and 12. is gripped by the sheet gripper 13 waiting at the clamp starting position.

This seat gripper 13 has sprocket wheels 14, 1
It is attached to the chain IT that extends over the chain IT 5, and a pair of chains on the back side (not shown) that are configured similarly to the chain IT. As shown in FIG. 2, the chain gripper 13 includes a sheet holding claw 13b that is swingable with respect to a support shaft 13a.
and a stopper 13c, and when this chain gripper 13 is waiting at the position shown in FIG. . Then, when the leading end of the transfer sheet S collides with the stopper 13c by the aforementioned feeding rollers 11 and 12, and at the same time, the visible image on the photosensitive drum 1 also comes to the transfer position A, as described above, The chain 17 is configured to rotate in the direction of arrow b, and this rotation closes the sheet presser claw 13b as shown by the solid line.
In this state, that is, with the leading end of the transfer sheet S being clamped, the transfer sheet S is conveyed, and the sheet S contacts the surface of the photoreceptor drum 1 at the transfer position A, and the visible image on the surface is The image is transferred to the sheet S. Further, as the chain 17 rotates, the sheet gripper 13 that clamps the transfer sheet S is connected to the fixing devices 18 and 19 facing each other.
During this time, the transferred image on the transfer sheet S as the sheet to be fixed is fixed by heat radiation from the fixing devices 18 and 19.

After this fixing, the transfer sheet S unclamped from the sheet gripper 13 passes through a pair of discharge rollers 21 and
It is stored in the storage section 22. In this way, the transfer sheet
The sheet is conveyed between the fixing devices by a sheet conveying device consisting of a chain 17 and a sheet gripper 13. Here, in FIG. 1, feeding rollers 11, 1
If the sheet feeding action of 2 is not performed smoothly or the clamping action of the sheet gripper 13 is not performed reliably, the leading edge of the transfer sheet S may come off from the sheet gripper 13.

Furthermore, there is a possibility that the transfer sheet S may not be gripped by the sheet gripper 13 from the beginning. If the above-mentioned problem occurs, it will cause serious problems with the copying machine. That is, for example, if the image fixing device 18,
When the leading edge of the sheet S gripped by the sheet gripper 13 comes off for some reason near the entrance side of the sheet gripper 19, the sheet gripper 13 continues to move by the driving action of the chain 17, and the transfer sheet S is also The leading edge continues to advance due to the paper feeding action of the feeding rollers 11 and 12. However, since the leading edge of the transfer sheet S is not gripped by the sheet gripper 13, the advancing direction of the leading edge becomes unstable, and if it enters the fixing devices 18 and 19 in this state, The same device (18, 19,
The tip of the sheet will come into contact with a heating element made of nichrome wire, etc., causing a fire.

This malfunction poses a serious problem to the copying machine, and is an extremely serious problem in terms of safety and damage to various devices within the copying machine. In view of the above-mentioned points, the present invention provides that when the leading edge of a sheet to be fixed, such as a transfer sheet, is not gripped by the sheet gripper 1, or when it is separated from the gripper, the sheet gripper 1 alone passes through the sheet gripper 1. A sheet entry prevention member is provided near the entrance side of the fixing device, and is configured to prevent sheets that are not gripped from entering the fixing device.
This is intended to prevent problems such as fire outbreaks.

The present invention will be explained below with reference to illustrated embodiments.

In FIG. 3, a sheet entry prevention member 24 is provided near the entrance sides of both fixing devices 18 and 19. Same member 2
4, as shown in FIG. 4, consists of an elastic plate 24a having extremely weak elasticity, and a mounting plate 24b fixed to the base of the elastic plate 24a and fixed to an immovable base plate (not shown). In FIG. 4, if the leading edge of the sheet S comes off the sheet gripper 13 while the sheet gripper 13 is conveying the transfer sheet S, the sheet gripper 13
The transfer sheet S moves while bending the elastic plate 24a of the sheet intrusion prevention member 24, and the transfer sheet S, which is advanced by the feeding action of the feeding rollers 11 and 12, is moved by the gripper 13.
After passing through, the elastic plate 24a, which returns to the position shown by the imaginary line due to its own elasticity, prevents it from entering the fixing devices 18 and 19. If the leading edge of the transfer sheet S is in a normal state where it is gripped by the sheet gripper 13, the gripper 13 continues to convey the transfer sheet S while bending the elastic plate 24a. In this manner, when the transfer sheet comes off, the sheet is prevented from entering the fixing device, so there is no risk of a fire occurring. here,
It would be extremely advantageous if the transfer sheet, which has been prevented from entering the fixing device, could be taken out of the copying machine by some means. In this case, in addition to the fixing path in the fixing device, another guide path may be provided to guide the transfer sheet that is not held in the grip to that path. That is, in FIG. 3, a guide passage 29 is provided between the fixing device 18 on the upper side and a shielding plate 28 forming a ventilation passage 27 for the cooling fan 26, and a guide passage 29 is provided on the entrance side of the shield plate 28 as shown in the figure. A roller pair 31 is provided. That is, the transfer sheet S that is prevented from entering the fixing device by the elastic plate 24a is
The transfer sheet S passes through the guide path 29 via the guide roller pair 31 while being guided by the guide roller pair 31, and the transfer sheet S passes through the feed roller (
(not shown) and the pair of feed rollers 16, and passes through a pair of discharge port rollers 21 to the storage section 2.
It is stored in 2.

An optical sensor 32 is provided in the guide path 29, and by its detection function, for example, a warning lamp is turned on to detect a state in which the transfer sheet has come off the sheet gripper 1, or a state in which it has not been gripped from the beginning. of,
It may be made clear to the user visually. In addition,
In the above embodiment, an elastic plate was used as the sheet entry prevention member, but in addition to this, as shown in FIG.
The base of the stopper piece 33b is fixed, and its shaft 33a
It is also possible to use a sheet entry prevention member 33 in which a torsion spring with very weak elasticity gives the sheet a tendency to rotate clockwise, and the stopper piece 33b swings against this tendency. By the way, FIG. 6 shows an embodiment in which a sheet ingress prevention member 34 having the function of a stopper can be moved in and out of the moving path of the sheet gripper 13.

That is, in the figure, the operating cam 35 rotates in the direction of the arrow in conjunction with the rotation of one of the sprocket wheels 15, and this rotation causes the link mechanism 36 to operate, and the sheet intrusion prevention member 3
4 is adapted to swing between the positions shown by solid lines and imaginary lines. First, when the sheet gripper 13 attached to the chain 17 moves in the direction of the arrow and comes to a position in front of the sheet intrusion prevention member 34 shown by the solid line, the cam portion 35a of the operating cam 35 that is rotating is attached to the shaft 37. The cam follower 39 of the pivoted operating rod 38 is pushed and moved. Then, the operating rod 38 rotates to the right around the shaft 37, and the arm 41, whose base is fixed to the shaft 42, is moved to the shaft 42 via the connecting rod 39.
Rotate to the left to the position indicated by the imaginary line using as a fulcrum. Above shaft 4
2 is rotatably supported by an unmovable member (not shown), and the shaft 42 of the arm 41 is rotated counterclockwise by the above-mentioned left-turning action of the arm 41, and this rotation causes the seat intrusion prevention member whose base is fixed to the shaft 42 to prevent sheet entry. The member 34 rotates from the solid line to the position shown by the imaginary line and retreats. In this state, the sheet gripper 13 in the figure passes, and then the cam blower 39 of the operating rod 38 moves to the cam portion 35a of the operating cam 35 that is rotating.
As a result, the seat entry prevention member 34 returns from the imaginary line to the position shown by the solid line via the connecting rod 39 and the arm 41. That is, the leading edge of the transfer sheet S is
If the transfer sheet S is detached from the sheet gripper 13 as shown in the figure, the advance of the transfer sheet S is prevented by the sheet entry prevention member 34 described above. Therefore, it is prevented from entering the fixing devices 18 and 19, and there is no risk of causing a fire or the like. The transfer sheet S whose entry is blocked may be guided to the above-mentioned guide path 29 (see FIG. 3), or the transfer sheet S may be detected by some means and transferred to the chain 17 or The feeding rollers 11 and 12 may be stopped. by the way,
An electrophotographic copying machine to which the present invention is applied, as shown in FIG.
The upper frame 43, which houses the photoreceptor drum 1 (see FIG. 1) and the like, can be opened upward.
In FIG. 3, when the transfer sheet S is detected by the optical center 32, the machine is stopped, the upper frame 43 is opened, and the transfer sheet S guided into the guide path 29 is taken out in this state. You can do it like this.

In addition, in the vicinity of the sheet entry prevention members 24 and 34 in FIG. 3 or FIG. 6 with the upper frame 43 open,
The transfer sheet S may also be taken out. As described above, the present invention allows only the sheet gripper 1 to pass when the leading edge of the sheet to be fixed, such as a transfer sheet, is not gripped by the sheet gripper 1 or is removed from the gripper 1, and A sheet entry prevention member that prevents sheets that are not caught in the fixing device from entering the fixing device is provided near the entrance side of the fixing device, thereby preventing problems such as fires. can be prevented, resulting in greater safety.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an example of an electrophotographic copying machine to which the present invention is applied, FIG. 2 is an enlarged view of a main part of the sheet gripper in the copying machine, and FIG. 3 is a safety diagram of an embodiment of the present invention. 4 is a side view of an electrophotographic copying machine incorporating the device, FIG. 4 is a diagram showing the operation mode of the sheet entry prevention member in the above safety device, FIG. 5 is a diagram showing an example using another sheet entry prevention member, and FIG. FIG. 6 is a side view showing the operation mode of another embodiment of the apparatus of the present invention, and FIG. 7 is a side view showing the operation mode of another embodiment of the apparatus of the present invention, and FIG.
It is a schematic side view which shows the aspect which was made to release. 13... Sheet gripper 1r...
Chain, 18, 19... Fixing device. 24,
33, 34... Sheet entry prevention member, S...
...Sheet to be fixed.

Claims (1)

[Claims] 1. A fixing position facing each other, a sheet conveyance device that conveys a sheet to be fixed between both of the fixing devices, a sheet gripper attached to the sheet conveyance device, and a sheet gripper attached to the sheet conveyance device that conveys the sheet to be fixed between the two fixing devices. and a sheet intrusion prevention member that is movable forward and backward so as to block the passage, and the leading edge of the sheet to be fixed is between a predetermined clamp starting position and the entrance side of both of the fixing devices.
When the sheet is not gripped by the sheet gripper or is released from the gripper, the sheet gripper is allowed to pass, and the sheet that is not gripped or gripped by the sheet gripper is allowed to enter the fixing device. A safety device for a copying machine, characterized in that the sheet entry preventing member prevents the sheet from entering.