JP2501911Y2 - Paper transport device for image forming apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention is directed to an image transfer position from a photoconductor in an image forming apparatus such as an electronic copying machine or a laser printer.
Regarding the device for positioning and feeding the leading edge of paper,
In particular, when arranging the gate claws corresponding to the registration roller device of the paper positioning device, it is possible to reliably position the leading edge of the paper, and even when the paper has a weak stiffness, the stopped paper is The present invention relates to a device capable of preventing the device from plunging into a nip position.

(Prior Art) In an image forming apparatus that uses an electrophotographic process, such as an electronic copying machine or a laser printer, a paper tray or other paper accommodating device is attached to a paper feed unit, and the paper accommodating device The paper is sent out one by one and sent toward the image transfer section through the paper transport path. In the image forming apparatus as described above, the paper is temporarily stopped by the paper positioning device immediately before the portion where the toner image formed on the image bearing member such as the photoconductor drum or the photoconductor belt is transferred to the paper, and the photoconductor is exposed. A means for sending again the toner image in time with the toner image formed on the body is used.

As shown in FIGS. 6 and 7, the paper positioning device is composed of a gate device, a registration roller device, and a transport roller device arranged upstream of the registration device. In the conventional example shown in FIG. 6, a sheet positioning device
The paper conveyance path in the 10th part is set by the upper and lower guide plates 11 and 15, and along the paper conveyance path from the paper feeding device side, the conveyance roller device 9, the conveyance roller device 40 configured as a slip roller, and the gate device. 20 and register roller device 30
Are arranged in this order.

The registration roller device 30 is arranged immediately in front of the image transfer portion, is stopped in a state where the leading end portion of the paper P is locked by the gate device, and is conveyed from behind from the conveyance roller device 9
By applying a feeding force by the transport roller device 40 as a slip roller, the leading end of the paper is pressed against a large number of gate claws to position the leading end. And
In synchronization with the toner image formed on the image carrier, the gate device 20 is opened, and the stopped paper leading end is fed to the nip portion by the registration roller device 30 with the loop Pa formed on the paper. , The function of feeding the paper is performed.

The relationship between the gate device 20 and the registration roller device 30 is configured as shown in FIG. In the example shown in FIG. 7, the registration roller device 30 is provided with a large number of roller members 32, 33 to 36 in a skewered pattern with respect to the shaft 31 at a predetermined interval. One gate claw 22,
23 ... are arranged respectively. Further, among the many gate claws, the gate claw 22 is a roller member near the reference line L.
The other gate claws are arranged inside 32, and are arranged corresponding to the reference line sides of the other roller members, respectively. Then, for each size of paper, when each gate claw locks the leading end of the paper, the end of the paper is prevented from being caught in the roller member and can be stopped. There is.

(Problems to be Solved by the Invention) However, in the conventional device as described above, when a weak paper such as Japanese paper or tracing paper is used, the leading end of the paper is pushed by the transport roller device. May cause buckling,
There is a problem that a part of the leading edge of the paper exceeds the stop position by the gate claw and is caught in the registration roller device.
This is, for example, a gate claw 23, as shown in FIG.
Even if the paper is stopped by 24, if the stiffness of the paper is weak, the action of feeding by the transport roller device 43 causes the leading end of the paper to bend and from between the gate claws to the nip position by the feed roller 33. There is a problem in that it is projected and the feeding action is given by the feeding roller.

Further, as shown in FIG. 9, when the paper enters the paper positioning device in the obliquely fed state, the corners of the leading end of the paper P rush into the nip portion of the roller member 32,
There is a problem that extra sheets are sent out. When the above-described protruding state of the paper occurs, the positioning effect of the leading end portion of the paper is not exerted well, and by transferring the toner image to the paper in such an obliquely feeding state, it is possible to achieve good performance. There is a problem that you cannot get a good copy.

Apart from the conventional example, as shown in FIG. 10, a portion corresponding to the gate device 20 is provided with a hole 16 for a guide plate, and an upper guide plate forming a sheet conveying path is, for example,
A downward bending portion 13 is provided corresponding to the hole 16 so that the sheet conveying path is narrowed. Then, by positioning the leading end of the sheet stopped by the gate device by the diaphragm portion, a means for preventing the sheet from being curved is configured. In the gate device 20 of the conventional example, the gate claw member is supported by the shaft 21, and is provided so as to swing the gate device by a driving means (not shown). Gate claws 20 ... Are provided so that the gate claws are interlocked with each other so as to project and retract toward the paper transport path.

However, even when the guide plate configured as described above is used, when the feeding force of the conveying roller device with respect to the sheet is stronger than the stiffness of the sheet, the leading end portion of the sheet P is folded downward. In some cases, the gate device is strongly pressed by the gate device to stop. Then, when the gate device is opened, the inconvenience arises that the leading end of the sheet is folded downward together with the gate device and is caught. Therefore, when the above-mentioned inconvenience occurs, the leading end of the sheet may be damaged or the sheet may be sent out at a delay, which causes a problem that a good copy cannot be obtained.

(Object of the Invention) The present invention solves the above-mentioned drawbacks of the conventional device, and can make the paper stop state of the paper positioning device good, and also for the paper with a weak stiffness, It is an object of the present invention to provide a device that does not cause a problem such as punch-through of a gate device.

(Means and Actions for Solving the Problem) The present invention is directed to paper positioning at a position immediately in front of the image transfer section with respect to a paper transport path arranged between a sheet feeding device and an image transfer section from an image carrier. The present invention relates to an apparatus in which an apparatus is arranged, the leading edge of a sheet is positioned by the sheet positioning apparatus, and the toner image formed on an image carrier is sent out in time. In the present invention,
The sheet positioning device includes a gate device provided with a plurality of gate claws, a registration roller device provided with a plurality of roller members, and a conveyance roller for feeding a sheet whose leading end is locked by the gate device. The gate device is configured so that the gate claws are positioned on both sides of the roller member of the registration roller device, and the rollers of the transport roller device are arranged corresponding to the gate claws. ing.

Further, in the present invention, in the paper positioning device,
A device for feeding out one side surface of the paper in a state of being regulated in accordance with a reference line is constituted, and a roller at the end on the reference line side constituting the conveying roller device is inside the roller at the end on the reference line side of the registration roller device. Arrange corresponding to the gate located,
The other rollers of the transport roller device may be arranged at positions corresponding to the gate claws arranged on the reference line side with respect to the rollers other than the rollers on the reference line side of the registration roller device. Further, in the present invention, a roller guide member and one hole corresponding to two gate claws are provided in the lower guide plate at a portion where the paper positioning device is arranged, and the gate claw is provided at an upstream portion of the hole in the sheet conveying direction. The upper folding part is formed by bending the lower guide plate upward so that the tip of the upper folding part approaches the upper guide plate, and the sheet conveying path formed between the upper guide plate and the lower guide plate is narrowed. It is also possible to arrange in a state.

(Operation) With the above-described configuration, the apparatus of the present invention can accurately set the stop position even for a weak paper, and may damage the leading edge of the paper. It is possible to prevent the occurrence of inconveniences such as And by accurately positioning the leading edge of the paper,
You can make a good copy. further,
In the sheet conveying device of the image forming apparatus of the present invention, since only the leading end of the lower guide plate is bent upward, there is no problem that the leading end of the sheet is wound downward by the gate device. It is possible to prevent the paper from being damaged.

(Embodiment) The configuration of the sheet conveying device of the image forming apparatus of the present invention will be described with reference to the illustrated example. The embodiment of the present invention shown in FIG. 1 shows the positional relationship among the transport roller device 40, the gate device 20, and the registration roller device 30 which constitute the paper positioning device 10. In the embodiment described above, the registration roller device 30 includes a large number of roller members 32 in a skewered shape with respect to the shaft 31.
~ 35 are provided, and the gate claws 22 to 28 of the gate device 20 are arranged with respect to these roller members. Since the arrangement relationship of the above-mentioned members is configured as shown in the conventional example of FIG. 6, for example, the side view corresponding to FIG. 1 is omitted. Further, each of the shaft 31 of the registration roller device, the shaft of the gate device, and the shaft of the conveying roller device is driven by a driving means (not shown). It is constructed in the same manner as in the paper positioning device.

The gate claws are provided so as to be located on both sides of each roller member. The roller member 32 on the reference line L side is provided with a pair of gate claws 22 and 23 on both sides. Gate claws 24, 25 are provided on the roller member 33 in the state of. Further, with respect to the gate claws arranged as described above, the feed roller on the upstream side of the gate claws corresponds to the lines 1, l2 ...
23 and the feed roller 42 are arranged in a relationship of the gate claw 24 and the feed roller 43.

Further, in the device of the present invention, the transport roller device 40 is configured as a slip roller,
The feed roller 42 at the reference line side end of the transport roller device is arranged at a position corresponding to the gate claw 23 located inside the roller 32 at the reference line side end of the registration roller device, and the other rollers 43 to 45 are arranged.
Are arranged at positions corresponding to the gate claws 24, 26, 28 arranged on the reference line side with respect to the other rollers of the feed roller device.

As described above, by setting the relationship among the gate device, the registration roller device, and the conveyance roller device, in the paper positioning device of the present invention, as shown in FIGS. 2 (a) and 2 (b), the paper is stopped. Can be satisfactorily performed. In the case shown in FIG. 2 (a),
The figure shows the case where the paper enters the paper positioning device in the state of oblique feeding, but even in that case, the corner portion of the paper on the reference line side first contacts the gate claw 22 and then the gate claw 22.
Since the leading end of the sheet comes into contact with 23, it is possible to prevent the leading end of the sheet from penetrating the gate claw and projecting to the nip portion by the registration roller device. Also,
As mentioned above, when the paper comes into contact with the gate claw in the state of oblique feeding, after the first corner of the paper hits,
Still further, the feeding action of the transport roller device eliminates the oblique feeding state of the sheet, and the sheet is positioned and stopped at the position where it is entirely in contact with the gate claw.

The example shown in FIG. 2B shows a case where the leading end of the sheet P stopped by the gate device 20 is likely to buckle when the sheet P is weak. However, when the combination of the gate claw and the roller member as shown in the first aspect of the present invention is used, the leading edge of the paper is locked by the two gate claws 22 and 23 on both sides of the roller member 32. It is possible to prevent the leading end of the sheet from entering the nip portion formed by the roller member 32. Further, even if the feed force is applied to the paper whose front end is stopped by the gate claw by the feed roller 42 on the upstream side, the feed force is particularly concentrated on the part of the gate claw 23. Does not buckle at the rollers.

With the above-described configuration, in the paper positioning device of the present invention, even when the paper enters the stop position in a state of being obliquely fed, or when handling a weak paper,
It is possible to prevent the leading end portion of the paper from buckling or entering the nip portion of the roller member as in the case of the conventional apparatus. Therefore, in the present invention, it is possible to prevent the leading end of the paper from being damaged and prevent the paper from being positioned incorrectly, and it is possible to make a good copy.

FIG. 3 shows the configuration of the image transfer unit, the paper positioning device 10, and the paper transport path of the image forming apparatus to which the paper positioning device of the present invention is applied. In the example shown in FIG. 3, a belt-shaped photoreceptor 1 is used as an image carrier, and a toner image is formed on the photoreceptor 1 in the same manner as in the case of an apparatus using a general electrophotographic process. A transfer corotron 3 is provided in the toner image transfer portion 2.

A sheet positioning device 10 is arranged immediately in front of the image transfer portion in the sheet conveying path 8 for feeding the sheet to the transfer portion, and the sheet positioning device 10 is provided upstream of the sheet positioning device 10 as in the case of a normal copying machine. A paper feeding device and a manual feed tray 5 are provided.

A manual paper feeding device 6 is provided in the paper feeding unit from the manual paper feeding tray 5, and a conveyance roller device 7 is arranged downstream of the manual paper feeding device 6.
A transport roller device 9 is arranged at a downstream portion of the paper transport path 8 from a paper feed device such as a paper tray, and the action of feeding the fed paper toward the paper positioning device 10 by these transport roller devices. To perform. Then, the sheet conveying path from the manual feeding tray 5 is merged with the sheet conveying path 8 from the sheet feeding device at an upstream portion of the sheet positioning device 10, and the sheet is conveyed through any sheet conveying path. However, the sheet positioning device 10 is configured so that the sheet can be positioned and fed toward the image transfer portion. Further, the paper positioning device 10 may use a device having a mechanism as shown in FIG. 1, and the gate device 20 functions to position the leading end portion of the paper so that the toner image formed on the photoconductor is formed. The gate device is opened at the same timing, and the registration roller device 30 feeds the paper toward the transfer portion.

(Means for Preventing Rolling Up of Paper by Gate) FIGS. 4 and 5 show the construction of the guide plate in the paper positioning apparatus of the present invention. In the example shown in FIGS. 4 and 5, FIG. 4 shows a cross section without the roller member, and FIG. 5 shows a guide plate 15 corresponding to the hole 16.
And the roller 32 and the gate claws 22 and 23. In the example shown in FIG. 4, the gate claw of the gate device 20 is supported by the shaft 21, and the gate claw is moved in and out of the sheet conveying path by the driving means (not shown) as in the case of each of the embodiments. Let it work.

As shown in FIG. 4, at the position where the claw of the gate device 20 appears in and out of the paper transport path, the upper guide plate 11 that sets the paper transport path is formed in a substantially horizontal state.
Reference numeral 15 is an upstream portion corresponding to the hole 16 and forms an upper folding portion 17. The tip portions of the upper guide plate 11 and the lower guide plate 15 are
Between the upper guide plate 11 in the horizontal state and the lower guide plate 15 bent upward by the upper folding portion 17, the paper conveyance path is narrowed upward and squeezed.

In the example shown in FIG. 5, the holes 16 provided in the guide plate
On the other hand, the roller member 32 of the registration roller device 30 is arranged, and the shaft 31 is arranged so as to cross the hole portion thereof. In addition, at the portion of the upper folding portion 17 corresponding to the gate pawl, a protrusion is formed by inclining the end portion of the lower guide plate upward so as to approach the gate pawl, and the gate pawl corresponds to the protrusion. 22 and 23 are located on both sides of the roller.

As shown in FIG. 4, the tip portion of the protruding portion of the upper folded portion 17 provided on the lower guide plate 15 forms a narrowed portion with respect to the upper guide plate 11 with a predetermined gap. And
By arranging the gate device in the narrowing portion, the leading edge of the paper stopped by the gate device is excessively projected obliquely downward from the paper transport path toward the gate device, or is located below the paper transport path. It is prevented from being bent toward the side. By configuring the guide plate as described above, the sheet P stopped by the gate device is
Unlike the case in the figure, it does not bend downward and is locked to the gate claw with the leading edge slightly upward, so even if the claw of the gate device descends, the leading edge of the paper does not It is possible to prevent the person from being caught in the vehicle.

Therefore, by forming the upper folding part 17 only on the lower guide plate which constitutes the paper transport path of the present invention, it is possible to prevent the leading end of the paper from being damaged or the paper to be rolled up. The quality will not be lost. In the embodiment of the present invention, an upper folding portion is formed on the lower guide plate of the sheet conveying path, gate claws are arranged on both sides of the roller member, and the feed roller is arranged corresponding to the gate claw. It is also possible to individually apply each means such as the above to the sheet conveying path of the conventional image forming apparatus. On the other hand, by combining all of the above-mentioned means, it is possible to provide an apparatus that can exhibit good paper handling performance.

(Advantages of the Invention) Since the sheet conveying device of the image forming apparatus of the present invention has the above-mentioned configuration, the above-mentioned mechanisms are applied to the sheet positioning device portion of the conventional image forming apparatus. By doing so, it is possible to make a good copy by accurately positioning the leading edge of the paper. Further, in the device of the present invention, it is possible to accurately set the stop position even for a weak paper, and prevent inconvenience such as damage to the leading end of the paper. I can. Further, in the sheet conveying device of the image forming apparatus of the present invention, since only the leading end of the lower guide plate is bent upward, there is a problem that the leading end of the sheet is wound downward by the gate device. It is possible to prevent the paper from being damaged.

[Brief description of drawings]

FIG. 1 is a plan view of the paper positioning apparatus of the present invention, and FIG. 2 is an explanatory view of the paper stopped state by the paper positioning apparatus of the present invention. FIG. FIGS. 3 (b) and 3 (b) respectively show the case of stopping a weak paper, FIG. 3 is an explanatory view of an image forming apparatus to which the present invention is applied, and FIG. 4 shows the construction of a guide plate in the paper positioning device. FIG. 5 is a side view, FIG. 5 is a plan view showing the structure of the lower guide plate corresponding to FIG. 4, FIG. 6 is a side view of a general sheet positioning device, and FIG. FIG. 8 is a plan view showing the relationship of gates, FIG. 8 is an explanatory view when stopping a weak paper in a conventional apparatus, FIG. 9 is an explanatory view when a paper is obliquely fed, and FIG. 10 is a paper. It is explanatory drawing in the case where the front-end | tip part of is caught in a gate apparatus. Reference numeral 1 in the figure: 1 photoconductor, 2 image transfer unit, 5 manual feed tray, 8 paper transport path, 10 paper positioning device, 11
… Upper guide plate, 15 …… Lower guide plate, 16 …… Hole, 17 …… Upper folding part, 20 …… Gate device, 22 to 28 …… Gate claw, 30…
… Registration roller device, 32-35 …… Roller member, 40 …… Conveying roller device, 42-45 …… Feeding roller.

Claims (3)

(57) [Scope of utility model registration request] 1. A paper positioning device is arranged immediately in front of the image transfer portion with respect to a paper conveyance path arranged between a paper feeding device and an image transfer portion from an image carrier. In a device configured to position the leading end of a sheet and send out the toner image formed on an image carrier at a timing, the sheet positioning device includes a gate device provided with a plurality of gate claws and a plurality of gate devices. A registration roller device provided with a roller member, and a conveyance roller device that feeds a sheet whose front end is locked by the gate device. Both sides of the roller member of the registration roller device are provided. The gate device is configured such that the gate claw is located in the gate claw, and the roller of the transport roller device is arranged corresponding to the gate claw. Sheet conveying device of the image forming apparatus. 2. A sheet positioning device is arranged immediately in front of the image transfer portion with respect to a sheet conveying path arranged between a sheet feeding device and an image transfer portion from the image carrier, and the sheet positioning device is provided with the sheet positioning device. An apparatus configured to position the leading edge of a sheet, align the timing with a toner image formed on an image carrier, and send out the side surface of the sheet in line with a reference line. The rollers at the ends of the registration roller device are arranged corresponding to the gates located inside the rollers at the reference line side of the registration roller device, and the other rollers of the transport roller device are other than the rollers on the reference line side of the registration roller device. The sheet conveying device of the image forming apparatus, which is arranged at a position corresponding to each of the gate claws arranged on the reference line side with respect to the roller. 3. A portion in which the paper positioning device is arranged,
1 corresponding to the roller member and the two gate claws on the lower guide plate
Two holes are provided, and an upper folding part is formed by bending the lower guide plate upward corresponding to the gate claw at the upstream part of the paper feeding direction of the hole, and the tip of the upper folding part approaches the upper guide plate. The sheet conveying device of the image forming apparatus according to claim 1 or 2, wherein the sheet conveying path formed between the upper guide plate and the lower guide plate is arranged in a narrowed state. .