JPH0228449A - Paper feed device - Google Patents

Abstract

PURPOSE:To prevent damage to the top edge of paper by installing a guide means in such a manner that the top edge of paper is first brought into contact with a pinch roller and forming a pinch roller as a low-friction member. CONSTITUTION:An upper roller is an ordinary rubber roller serving as a driving roller 11, while a lower roller, made of polyacetal resin, etc., serves as a pinch roller 12. The surface of the pinch roller 12 is smoothed to reduce its sliding frictional resistance. Also, a guide member 5, made from resin film, is provided under an upper guide plate. As paper is conveyed over a paper conveying path, its top edge is guided toward the pinch roller 12 by means of the guide member 5. The paper then slides with its top edge first brought into contact with the pinch roller 12, and is guided to a nip portion between the rollers as the pinch roller 12 rotates.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a conveyance roller device for a paper conveyance path in an image forming apparatus such as a copying machine. Configure
The present invention relates to a paper feeding device that can prevent damage to the leading edge of paper.

(Prior Art) In an image forming apparatus such as a copying machine, paper conveyed from a paper feeder is passed through a gate or a registration roller device (hereinafter referred to as registration roller device).
A method is used in which the paper is stopped once, the leading edge of the paper is positioned, and the paper is sent out toward the image transfer unit with the timing aligned with the image formed on the photoreceptor drum or the like. ing.

In the above-mentioned paper conveyance device, for example, as shown in FIG. A gate 15 is arranged so that the paper conveyed through the paper conveyance path 1 is temporarily stopped by the gate 15, and is made to stand by with a loop formed at the leading end of the paper.

Then, the gate 15 is opened in synchronization with the toner image formed on the image carrier such as a photoreceptor drum, and the leading edge of the paper is nipped between the drive roller 11 of the registration roller device 10 and the pinch roller 12. Then, the paper is conveyed in such a state that the leading edge of the paper is accurately positioned toward the toner image transfer position.

(Problems to be Solved by the Invention) However, in the registration roller device 10 as described above, the drive roller 11 and the pinch roller 12 are each made of a rubber roller. Since it is made of a material with a large coefficient of friction, problems as shown in FIGS. 5 and 6 occur.

In other words, when the paper is sent out toward the registration roller device, the leading edge of the paper P comes into contact with the roller 11a as shown in FIG. The paper is inserted into the nip between the rollers and the rollers, and is transported to the image transfer area by the registration roller device.

However, the paper comes into contact with the roller 11a and tlff i
) When the paper is rolled, it is rare for the leading edge of the paper to contact each roller uniformly, and in many cases, the leading edge of the paper contacts each roller with a slight difference in contact time. It becomes a state where

Therefore, as shown in FIG. 6, the paper P may be slightly damaged at the portion where it came into contact with the roller, and scratches b may be formed at the portion where it slid against the roller.

If the scratches on the paper are very slight and only traces of scratches remain,
Although it is not a major problem, if the leading edge of the paper is bent and a scratch is formed, the leading edge of the paper may be misaligned, or the paper may get caught on the protrusion of the guide plate in the paper transport path. , problems such as paper jams may occur.

The problem of scratches on paper as described above is not a particularly big problem in the case of ordinary paper, but - for paper that has already passed through the fixing device and has been copied on one side, This can be a very serious problem when multiple copies are made or when paper absorbs moisture.

For example, paper that has been copied on one side tends to curl when it passes through a fixing device and is heated.
When the leading edge of the curled paper comes into contact with the rollers, it does not come into contact with all the rollers at the same time.

Therefore, the curled leading edge of the paper may come into strong contact with the roller, and large scratches may occur in that area. Due to the scratches that have occurred on a part of the leading edge of the paper, when the leading edge of the paper is placed against a registration gate etc. to perform an operation such as positioning the paper, the leading edge of the paper may be Misalignment may occur at the leading edge of the paper regardless of the condition.

This misalignment in the positioning of the leading edge of the paper appears as misalignment of images when multiple copies are made, and especially when making color copies, color misalignment may occur between the overlappingly transferred color images. This causes a significant decrease in the commercial value of the copy.

(Object of the Invention) The present invention solves the drawbacks of conventionally used devices as described above, and includes a guide means so that the leading edge of the paper comes into contact with the pinch roller first. It is an object of the present invention to provide a paper feeding device which can prevent scratches from occurring at the leading edge of the paper by forming the pinch roller with a low friction member with a smooth surface.

(Means and operations for solving the problem) The paper feeding device of the present invention positions the leading end of the paper being transported in the paper transport path and uses a device such as a registration roller that performs the operation of feeding the paper. The pinch roller of the registration roller device is made of a material with a low coefficient of friction, and the surface of the roller is formed in a highly smooth state, and the leading edge of the roller is made of a material having a low coefficient of friction. A guide means is provided to bring the roller into contact with the pinch roller.

Therefore, in the paper feeding device of the present invention, when positioning the leading edge of the paper, there is no damage to the part that contacts the roller, so there is no misalignment with respect to the image formed on the image carrier. etc. will not occur, and problems in the creation of multiple copies will be prevented.

In addition, since no traces of friction with the rollers or folded parts are formed on the leading edge of the paper, it is possible to
It becomes possible to reduce the causes of jamming.

(Example) The configuration of the paper feeding device of the present invention will be described according to the illustrated example.

In the embodiment shown in FIG. 1, the paper conveyance path 1 is configured such that a lower guide plate 2 and an upper guide plate 3 are arranged in parallel with each other at a predetermined interval, and the paper is guided between the two guide plates. A registration roller device 1o is provided at a predetermined position on the paper conveyance path 1.

In the registration roller device 10 of the present invention, both rollers are arranged so as to protrude from holes provided in the guide plate toward the paper conveyance path. As the pinch roller 12, a roller made of polyacetal resin or the like is used.

Then, the surface of the pinch roller 12 is formed smoothly,
Slip I! The Jm resistance is set small so that when the paper comes into contact with each other, the leading edge of the paper can be smoothly guided toward the nip position between both rollers.

Further, in the paper conveyance path of the present invention, a guide member 5 made of a resin film is provided inside the upper guide plate 3. As this guide member 5, a member having elasticity and low sliding resistance against the paper, such as Mylar (trade name), is used, and the guide member 5 is connected to the upper guide plate 3.
By affixing it to the bottom surface and placing its tip close to the nip between the two sides, it is possible to better guide the paper being conveyed through the paper conveyance path. Become.

By using the guide member configured as described above and the registration roller device, the leading end of the paper being conveyed in the paper conveyance path is guided toward the pinch roller 12 by the guide member 5. , while the leading edge of the paper is sliding in contact with the pinch roller 12,
When the paper is guided to the nip between the two rollers by the rotation of the pinch roller 12, the leading edge of the paper is
Unlike in the case of rubber rollers, there will be no occurrence of a single habitual scratch due to Iam with the roller.

Then, when the leading edge of the paper is stopped in contact with the nip portion of the registration roller device II 10 and is fed out by the next rotation of the registration roller device 10, the leading edge of the paper is positioned. In a state where the action is accurately performed, it is sent to an image transfer portion such as a photoreceptor drum.

Further, in the registration roller device 10 of the present invention as described above, a gate 15 as shown in FIG. 2 may be provided at the upstream portion of the registration roller device 10. The driving force mJif+ of this gate is the solenoid 17 and the spring 1.
The solenoid 17 and the spring 18 are connected to a bracket that protrudes from the support portion of the gate 15 (7) @ 16, and the gate 15 is connected to the paper conveyance path by the on/off operation of the solenoid. It is configured to be able to close the paper transport path and open the paper conveyance path.

In the roller device configured as described above,
Similar to the roller device shown in Fig. 1, the pinch roller is made of a low-friction member, its surface is formed in a circular shape, and the paper is conveyed in such a state that the leading edge of the paper comes into contact with the pinch roller first. By configuring the path, sliding scratches and the like will not be formed on the leading edge of the paper.

As shown in FIG. 2 above, when the gate 15 is disposed at the upstream portion of the registration roller device 10, as shown in FIG.
The convex portion 5a is formed in a combination with the roller 1.
1a.

Further, the tip of the gate 15 can protrude into the concave portion 5b of the guide member 5, and the unevenness of the guide member is such that each roller unit constituting the roller device 1
1a, so that paper guidance and gate ejection and retraction operations can be performed in good condition.

By forming the guide member in such a state that the leading edge of the paper first contacts the pinch roller, it is possible to achieve the same effect as shown in FIG. 1 above. .

Furthermore, a drive roller 11 made of the rubber roller of the present invention
and a pinch roller 12 made of a material with a small coefficient of friction.
As a device used in combination, it is possible to configure a device as shown in FIG.

The example shown in FIG. 3 shows an example of configuring a paper feed path for feeding paper from a manual tray in a copying machine. Subsequently, a registration roller device 10 is placed in front of the image transfer portion.

Further, in the embodiment shown in FIG. 3, a guide member for bending the cardboard is provided in the paper conveyance path in order to improve the feeding effect on the cardboard. In this embodiment, the tip of the lower guide plate 26 at the discharge portion of the manual feed roller 25 is bent upward to form an upward protrusion 27, and the upward protrusion 4 of the upper guide plate 3 on the registration roller device @10 side The leading edge of the paper is brought into contact with the paper, the leading edge of the paper is bent along the upward protrusion 4, and the paper is introduced into the paper transport path.

The paper P guided through the paper conveyance path shown in FIG. 3 of the present invention has an upwardly protruding portion 27
Since the paper is bent upward at the part shown in FIG. This will prevent unforeseen situations such as accidents from occurring.

Therefore, when configuring the paper conveyance path as shown in FIG. 3, J'7
Even when inserting stiff paper from the manual feed tray, it is possible to accurately position the leading edge of the paper, and even when performing multiple copies on such paper, the image This makes it possible to obtain a copy in good condition without any deviation or the like.

In the registration roller device of the present invention described above, an example is shown in which the drive roller is arranged above the paper conveyance path and the pinch roller is arranged below, but the arrangement relationship of these rollers is not particularly limited. If the pinch roller is placed on the upper side, the guide member in the paper conveyance path is configured to guide the leading edge of the paper relative to the upper pinch roller. It is possible to achieve the object of the invention.

Furthermore, the paper feeding device of the present invention is not only applicable to copying machines, but can also be applied to other image forming devices such as printers and facsimile machines, and can be applied to any paper transport path of these devices. It is also possible to apply the present invention to a conveyance roller device.

(Effects of the Invention) Since the paper feeding device of the present invention has the above-described configuration, it is possible to prevent scratches etc. from being formed on the leading edge of the paper passing through the registration roller device, thereby preventing copying. It is possible to improve the commercial value of the paper and prevent jams from occurring in the paper transport path due to the leading edge of the paper being bent.

Furthermore, when using the registration roller device of the present invention, the leading edge of the paper is accurately positioned.
When making multiple copies, it is possible to obtain copies in good condition without image blurring or the like.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the configuration of a paper feeding device of the present invention, FIG. 2 is a side view of another embodiment of the present invention, FIG. 2a is a plan view thereof, and FIG. 3 is another embodiment of the present invention. FIG. 4 is a side view showing the configuration of a conventional device, FIG. 5 is an illustration of the relationship between the pinch roller and the paper, and FIG. 6 is an illustration of scratches occurring on the paper. . Reference numerals in the figure 1...Paper conveyance path, 2...Lower guide plate, 3...Upper guide plate, 4...Upward protrusion, 5... ... Guide member, 10 ... Registration roller device, 11 ... Drive roller, 12 ...
...Pinch roller, 15...Gate, 20.
... Conveyance roller device, 25 ... Manual feed roller, 27 ... Upward protrusion. Sea convex-' Fig. 1 Fig. 2 Fig. 2a Fig. 3 Fig. 4

Claims (1)

[Scope of Claims] A drive roller and a pinch roller are arranged to face each other so as to sandwich the paper transport path, and are configured to position the leading edge of the paper being transported within the paper transport path and transport the paper. In a device such as a registration roller provided in the paper conveyance path, the pinch roller of the registration roller device is made of a member with a low coefficient of friction, the surface of the roller is formed in a highly smooth state, and the surface of the roller is formed in a highly smooth state. 1. A paper feeding device comprising a guide means for causing a leading end of the paper to contact a pinch roller with respect to the paper being transported.