JPS63300037A - Feeder for image forming device - Google Patents

Abstract

PURPOSE:To restrain a double feeding prevention roller from being worn in an early stage as well as to prevent the tip end of a form from being crimped by providing a mechanism which allows the double feeding prevention roller to rotate by a specified angle only to the reverse feeding direction. CONSTITUTION:When the solenoid 39 of a specified angle rotating mechanism 37 is excited, the linear motion of a spindle (d) is transformed into the rocking motion of a standing arm 44, accompanied with which, double feeding prevention rollers 33 through 35 are rotated to the reverse feeding direction together with a lower section shaft 30 via a driven member 41 and an one-way clutch 40. The double feeding prevention acting position of the double feeding prevention rollers 33 through 35 against a carrying roller 32 is thereby changed and a cleaning body 36 abuts concurrently thereto so as to remove paper scraps and the like. No rotation to the reverse feeding direction being allowed, the tip end of a form will never be crimped to the reverse feeding direction by the double feeding prevention rollers 33 through 35, the form is thereby smoothly fed to a carrying device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a paper feeding device installed in an image forming apparatus such as an electrostatographic copying machine or a printer.

[Conventional technology]

For example, the paper feed device of an electrostatic photocopier has a paper feed device that feeds uncopied sheets one by one to the transfer unit each time a paper feed signal is input, and a paper feed device that inputs a refeed signal. An intermediate paper feeder for double-sided copying that feeds the paper after single-sided copying to the transfer unit each time, or a document feeder that feeds the original paper onto the document table each time a paper feed signal is input. There is a paper feeding device, and its paper feeding mode consists of conveyor rollers whose respective frictional resistances are greater than the frictional resistance between sheets, and a friction band to prevent double feeding.The roller axes are arranged in a zigzag pattern when viewed in the paper feeding direction. There are some that are partially overlapped when viewed from the direction.

According to this configuration, when two sheets of paper are fed between the conveyance roller and the friction pad by the paper feed roller, the leading edge of the paper on the friction pad side comes into contact with the friction pad and paper feeding is blocked. Based on this and the difference in frictional resistance mentioned above, only the paper on the transport roller side is fed.
So-called double feeding of paper is prevented.

However, since the conveyance rollers and friction pads are arranged in a zigzag pattern, the wear of the friction pads is slight compared to a configuration in which the friction pads are in contact with the conveyance rollers, but due to the relative friction of the paper against the friction pads. Secondly, the double-feed prevention function of the friction band (especially the pad corners) wears out early, and the double-feed prevention function is significantly reduced.
There was a drawback that the friction band had to be replaced frequently.

Therefore, as seen in Japanese Unexamined Patent Publication No. 60-61.434, the friction pad and conveyance roller for preventing double feeding are arranged so that they form a zigzag shape when viewed from the roller axis direction. The transport rollers are arranged so as to partially overlap each other, and the conveying roller is rotated in the paper feeding direction and the double feeding prevention roller is rotated in the opposite direction to the paper feeding direction, thereby suppressing uneven wear of the double feeding prevention roller. As a result, a paper feeding device has been proposed that maintains the function of preventing double feeding well over a long period of time.

[Problem that the invention seeks to solve]

However, since the double-feed prevention roller is rotated in the opposite paper feeding direction, the relative friction between the paper and the double-feed prevention roller becomes larger than in the conventional case where the friction pad is fixedly installed. Although the lifespan is longer than when the friction pad is fixedly installed, rotating the double-feed prevention roller causes premature wear of the double-feed prevention action portion (particularly the roller corner), which is the circumferential surface of the roller. This led to a decline in the function of preventing double feeding.

In addition, the ability to prevent double feeds was also degraded due to silicone oil, paper dust, etc. that became mist and scattered from the fixing device into the machine, adhering to the double feed prevention rollers.

A further problem is that the leading edge of the paper whose double feeding is prevented by the double feeding prevention roller receives a return rotational force in the opposite paper feeding direction, causing the leading edge of the paper receiving the returning force to rotate in the opposite direction. In some cases, the sheet may have a tendency to bend in the direction of the sheet, and in the subsequent fixing process, an inconvenient situation has also been observed in which the leading edge of the sheet with the sharp tendency bends due to the fixing pressure.

The present invention has been made in view of the above circumstances, and
The object of the present invention is to provide a paper feeding device that can prevent premature wear of the double-feed prevention roller by 1 full full range through extremely rational improvements, and also prevents the leading edge of the paper from bending.

[Means for solving problems]

In order to achieve the above object, the present invention aligns the conveyance roller and the roller for preventing double feeding of paper so that the sheet conveyance acting portion between both rollers has a zigzag shape when viewed in the paper feeding direction. a mechanism for rotating the double-feed prevention roller by a predetermined angle only in the counter-feeding direction by inputting a rotation signal; The feature is that the cleaning body is placed in contact with the cleaning body.

[Function] According to the characteristic configuration described in 2, when the double-feed prevention roller is rotated by a predetermined angle, the double-feed prevention roller becomes a fixedly arranged friction pad, and this double-feed prevention roller double feeding of paper is prevented.

The fact that the double-feed prevention roller becomes a fixedly arranged friction pad means that the double-feed prevention roller is more sensitive to paper feeding than a structure in which the double-feed prevention roller rotates in the opposite direction. The amount of wear is reduced, and uneven wear of the double-feed prevention roller is suppressed by rotation of the double-feed prevention roller over a predetermined angle, and the double-feed prevention roller is rotated. Coupled with the fact that the double-feed prevention action section is cleaned every time the sheet is loaded, double-feed prevention of sheets is well maintained over a length of 1υI.

[Embodiments] Hereinafter, embodiments of the present invention will be described based on the drawings. Fig. 2 schematically shows an electrostatic photocopying machine capable of selecting one-sided copying and two-sided copying, and an automatic document feeder 1. A document presser 2 is provided on the upper part of the copying machine main body 3, and a photoreceptor drum 4 is mounted horizontally on the copying machine main body 3, and around the photoreceptor drum 4, a charging device 5, a developing device 6, transfer device 7,
A paper separation device 8 and a cleaning device 9 are arranged in that order in the rotational direction of the photosensitive drum 4, and an exposure device (1) with a moving optical system is arranged in the upper space of the copying machine main body 3, and further, Manual feed section 11 or cassette case 12
a paper feed conveyance device 13 that conveys the paper inside to the transfer device 7;
A paper discharge conveyance device 15 that transports the paper after transfer and separation to the fixing device 14, and a pair of paper discharge rollers 17 that discharge the paper after the fixation to a tray 16 are provided.

A refeeding device 18 having a function of preventing double feeding is provided in the lower space of the copying machine main body 3, and a switchback a mechanism 19 selectively discharges the fixed paper to the refeeding device 18. is disposed between the fixing device 14 and the pair of paper ejection rollers 17, and further includes a conveying device 20 that merges and feeds the paper after single-sided copying stored in the paper refeeding device 18 to the paper feeding and conveying device 13. At the same time, a large-capacity case 21 of an elevator set capable of storing a large capacity of paper is provided below the arrangement part of the cassette case 12, and the paper from the case 21 is Conveyance device 2o
A paper feeding device 22 is provided which has a function to prevent double feeding for feeding multiple sheets.

That is, the manual feed section 11 or the cassette case 2.
One is a one-sided copying mode in which an image is copied onto one side of a sheet of paper that is fed from 1, and the sheet after one-sided copying is discharged to a tray 16, and the other is that the sheet is fed from the paper re-feeding device 18 at a predetermined timing. The configuration is such that it is possible to select a double-sided copy mode in which an image is copied on the back side of the paper after single-sided copying, and the paper after double-sided copying is discharged to the tray 16.

As shown in FIG. 1, the large-capacity cassette 71-case 21 is provided with a loading plate 23 that can accommodate, for example, 2,500 sheets of paper, on the case body 24 and can be moved up and down by a drive. Separation claw 2 that acts on the front edge shoulder of the paper
5 (this is not an essential configuration), and the paper feed device 22 for this large capacity cassette case 2I is:
It consists of a paper feed roller 26 that feeds out the uppermost paper, and a double feed prevention means 27 that feeds the paper fed by the paper feed roller 26 to the conveyance device 2o in a state where double feed is prevented.

Specifically, as shown in FIGS. 3 to 6, the double feeding prevention means 27 includes a pair of upper and lower shafts 29 and 30 disposed above and below a guide body 28 for paper feeding, and roller 2
A transmission gear 31 to the upper shaft 29 and a conveying roller 32.32 are provided at predetermined intervals on the upper shaft 29, while the conveying roller 32.
The width of the center double feeding prevention roller 33 is slightly wider than the width of 32.
and an intermediate double-feed prevention roller 34.34 having a smaller diameter than the central double-feed prevention roller 33 and a little wider than the conveyance roller 32.32, and a roller 34. Double-feed prevention rollers 35 and 35 are integrally molded with a diameter and sandwiched between the center double-feed prevention rollers 33 between the conveyance rollers 32 and 32, and the center double-feed prevention roller 33 The integrally molded rollers 33 to 35 are provided on the lower shaft 30 so that the conveying rollers 32 and 32 are inserted between the double feeding prevention rollers 35 and 35 on both sides thereof, respectively.

That is, the upper conveyance roller 32.32 and the lower double-feed prevention roller 33.35.35 are connected to the upper and lower shafts 29.3 so that they partially overlap when viewed in the roller axis direction.
0, so that a zigzag paper feeding conveyance section is formed when viewed in the paper feeding direction.

For this roller arrangement, an opening 36 is provided in the guide body 28.
At the upstream edge of this opening 36 in the paper feeding direction and corresponding to the upper surface of the double feed prevention roller 33. A guide plate section a located near the front half is arranged in series.

Then, a cleaning body 36 made of sponge (can be modified to be made of felt, brush, etc.) is attached to the double-feed prevention action portion that is the circumferential surface of the double-feed prevention roller 33, 34, 34, 35, 35. The rollers 33, 34, 34, 35 for preventing double feeding are provided on the lower side of the guide body 2, in contact with each other.
．． A rotation mechanism 37 that rotates 35 by a predetermined angle in the opposite paper feeding direction.
are connected to one end side of the lower shaft 30.

The rotation mechanism 37 described above is configured as follows.

That is, the solenoid bracket 38 is attached to the case body 24.
In addition, a solenoid 39 is installed on this bracket 38.
and a driven member 41 is connected to one end side of the lower shaft 30 via a one-way clutch 40,
A shaft 42 parallel to the lower shaft 30 is rotatably pivoted to the bracket 38, and a horizontal arm 43 is connected to one end of the shaft 42, and a pin C is connected to the elongated hole of the arm 43. The spindle d of the solenoid 39 is linked to the spindle d of the solenoid 39, and an arm 44 is connected upright to the other end of the shaft 42, and the driven member 41 is connected to the long hole e of the arm 44 through a pin. It is made by linking.

The solenoid 39 is configured to receive a signal that excites the solenoid 39 for a predetermined time when a mode for feeding paper from the large-capacity cassette case 21 is selected.

Then, the above excitation signal is input to the solenoid 39 and the 8
When the solenoid 39 is energized, the front δ spindle d
is driven in the direction of retiring into the solenoid case g (from the state shown in FIG. 5 to the state shown in FIG. 6), and this linear motion of the spindle d is converted into a swinging motion of the upright arm 44, and Interlockingly, via the driven member 41 and the one-way clutch 40, the double feed prevention rollers 33, 34, 34, 35, 35 rotate together with the lower shaft 30 in the opposite paper feeding direction, and the transport rollers 32. The position of the double-feed prevention action portion of the double-feed prevention rollers 33.34, 34.35.35 relative to 32 is changed, and the double-feed prevention action of the double-feed prevention rollers 33.34.34.35°35 is changed. Since the cleaning body 36 is in contact with the portion, the cleaning body 36 cleans and removes silicone oil mist, paper powder, etc. adhering to the double feeding prevention portion.

Then, when a predetermined time has elapsed after inputting the excitation signal, the solenoid 39 is demagnetized and the driven member 41 is operated to return to its original position (from the state shown in FIG. 5 to the state shown in FIG. 6). However, the double feeding prevention roller 33.
34.34.35.35 The cleaning body 3 is installed in the double feed prevention action part.
6 are in contact with each other, and the contact braking force of the cleaning body 36 is applied to the lower shaft 30, and a one-way clutch 40 is provided between the lower shaft 30 and the driven member 41. Therefore, even if the driven member 41 is operated to return to its original position, the double feeding prevention rollers 33, 34, 34
．． 35, 35 do not rotate, that is, each time the paper feeding mode from the large capacity cassette case 21 is set, the double feeding prevention rollers 33, 34, 34, 35, 35 move in the opposite paper feeding direction. It is rotated by a predetermined angle.

Each time the print switch is activated under the above paper feeding mode, the uppermost paper is fed by the paper feed roller 26 toward the double feeding prevention means 27, and the paper is transported by the paper feed roller 26. Roller 32.32 and double feed prevention roller 3
3.34.34.35.35, and at this time, the double-feed prevention rollers 33.34.34.35, 35 are fixed. In other words, since it is not rotating in the counter-feeding direction, the leading edge of the paper is not bent in the counter-feeding direction due to the double-feed prevention rollers 33, 34, 34, 35, 35. Since the leading edge of the paper is guided by the guide plate section a and introduced into the paper conveyance action section, the leading edge of the paper does not come into contact with the double-feed prevention rollers 33, 34, 34, 35, 35 and bend. The paper is then smoothly fed to the conveying device 20.

On the other hand, the frictional resistance of the conveyance roller 32.32 is greater than the frictional resistance of the double feeding prevention roller 33.34.34.35.35, and the frictional resistance of the double feeding prevention roller 33.34.34
．． The frictional resistance of 35, 35 is set to be larger than the frictional resistance between sheets of paper, so that when two sheets of paper are piled up by the paper feed roller 26, the paper is transferred to the transport roller 32.3.
2 and the double-feed prevention roller 33.34.34.35.35, the double sheet of paper comes into contact with the double-feed prevention roller 33.34.34.35.35. Based on the fact that paper feeding is blocked by the transfer rollers 32 and 32 and the difference in frictional resistance, only the paper on the conveying rollers 32 and 32 side is fed.

Another embodiment of the cleaning body 36 is shown in FIG. This cleaning body 36 is made up of soft cleaning body parts 36a, 36a made of sponge (can be transformed into felt, bran, etc.) and hard braking body parts 36b on both sides.
A soft cleaning body portion 36a,
36a to double feed prevention rollers 33.34, 34.35.3
5. A hard braking body portion 36b that serves as a double feed prevention action portion on the circumferential surface.
are provided on the lower side of the guide body 28 in contact with the double-feed prevention action portions at the outer corners of the double-feed prevention rollers 35 and 35, respectively.

In addition, the double feeding prevention roller 33.34.34.35.3
The intermediate double-feed prevention rollers 34 and 34 of No. 5 function well in preventing double-feeding of paper, but the rollers 34 and 34 that function mainly to prevent double-feeding of paper are Double feeding prevention rollers 33, 35, 35 at the center and both sides forming a zigzag paper feeding conveyance section, and
The intermediate double-feed prevention rollers 34, 34 may be omitted.

Further, the mechanism 37 for rotating the double feed prevention roller 33, 34, 34, 35° 35 by a predetermined angle is mainly composed of a solenoid 39 and a one-way clutch 40, and the cleaning body 36 is used to prevent double feed. roller 33.34゜3
4.35.35, it is configured to also serve as a braking body for preventing co-rotation in the paper feeding direction, but a clutch with a brake is provided on one end side of the lower shaft 30, and a rotational drive system is interlocked with the clutch, Further, the control structure may be such that the clutch transmits power for a predetermined period of time. In other words, the specific structure of the rotation mechanism 37 can be modified in various ways.

Furthermore, in the above embodiment, the paper feeder 22 of the large-capacity cassette case 21 was explained, but the paper feeder is also a paper feeder for refeeding paper for double-sided copying! 7, the manual feed section 11, or the cassette case 12, or the paper feeding devices of various image forming apparatuses such as printers and facsimile machines, not just copiers. .

〔Effect of the invention〕

As explained above, in the present invention, the conveying roller and the roller for preventing double feeding of paper are partially overlapped when viewed in the roller axis direction so that the sheet conveying action section between both rollers has a zigzag shape when viewed in the paper feeding direction. Conventionally, in the paper feeding device of an image forming apparatus which is arranged with The double-feed prevention roller is rotated by a predetermined angle in the counter-feeding direction, so that the double-feed prevention roller turns into a fixedly arranged friction pad under rotation at a predetermined angle. Therefore, compared to a conventional configuration in which the double-feed prevention roller is rotated in the opposite paper feeding direction, the amount of wear of the double-feed prevention roller during paper feeding is reduced,
By rotating the double-feed prevention roller over a predetermined angle, uneven wear of the double-feed prevention roller is suppressed, and furthermore, by bringing a cleaning body into contact with the double-feed prevention roller, The double-feed prevention action portion of the double-feed prevention roller is cleaned every time the double-feed prevention roller is rotated, and this cleaning mode is synergistic with the abrasion and the suppression of the amount of wear. As a result, it has become possible to effectively maintain the prevention of double feeding of paper over a long period of time.

[Brief explanation of drawings]

Fig. 1 is a detailed view of the paper feeding device, Fig. 2 is a schematic longitudinal sectional side view of an electrostatic photocopier as an example of the image forming bag π, and Fig. 3 is an explanatory diagram of the double feeding prevention means with the cleaning body shown in an expanded view. , FIG. 4 is a detailed view of the double-feed prevention means, and FIGS. 5 and 6 are diagrams for explaining state switching of the double-feed prevention roller. FIG. 7 is an explanatory diagram showing another embodiment of the cleaning body. 32... Conveyance roller, 33. 35... Double feed prevention roller, 36... Cleaning body (braking body), 37... Predetermined angle rotation mechanism, 39... Solenoid, 40... One-way clutch. Applicant: Mita Kogyo Co., Ltd. Representative: Patent Attorney Hideo Fujimoto Figure 1 Figure 3 Figure 4 Figure 5 District 6

Claims (2)

[Claims] (1) The transport roller and the roller for preventing double feeding of paper are arranged so that the paper transport action section between both rollers has a zigzag shape when viewed from the paper feeding direction, with parts of the transport rollers overlapping when viewed from the roller axis direction. , a mechanism for inputting a rotation signal to rotate the double-feed prevention roller by a predetermined angle only in the counter-feeding direction;
A paper feeding device for an image forming apparatus, characterized in that a cleaning body is provided in contact with the double feeding prevention roller. (2) the predetermined angle rotation mechanism includes a one-way clutch connected to the double-feed prevention roller, and a solenoid that rotates the double-feed prevention roller in the opposite paper feeding direction via the one-way clutch; The image forming apparatus according to claim 1, wherein the cleaning body also serves as a braking body that prevents rotation of the double feeding prevention roller in the paper feeding direction. Paper feed device.