JPH02123045A - Sheet feeder - Google Patents

Abstract

PURPOSE:To surely separate a sheet of weak knee sufficiently pressed to a friction member by constituting a device such that a feeder unit feeds the sheet pressed by a pressing means to the friction member. CONSTITUTION:A feeder unit 16 feeds a sheet S, when its point end is adapted to a friction member 22, the sheet S is pressed to the friction member 22 by a pressing means 62. The sheet S, while it is pressed by the pressing means 62, is separated. As a result, double feed of the sheet S is reduced.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to a sheet feeding device used in an image forming apparatus such as a copying machine or a laser beam printer. The present invention relates to a sheet feeding device including a friction member (hereinafter referred to as a separation pad) and a friction member (hereinafter referred to as a separation pad).

(b) Conventional technology Conventionally, sheet feeding devices equipped with paper feeding rollers and separation pads are known.
The sheets are fed while being brought into frictional contact with a separation pad that is biased in the opposite direction, and the leading edges of the second and subsequent sheets are brought into contact with the separation pad to regulate feeding.

(C) Problems to be Solved by the Invention In the above-mentioned sheet feeding device, since the sheet being fed comes into frictional contact with the separation pad from the leading edge to the trailing edge, the feeding resistance increases and the sheet feeding roller This method has the drawback of accelerating wear and shortening the service life, and also eliminates the risk that the separation pad will wear out, reducing separation performance and causing double feeding of sheets.

To overcome this drawback, the present applicant has devised a sheet feeding device that separates the sheet to be fed from the friction member after the sheet is separated. A sheet with strong stiffness comes into contact with the friction member with sufficient pressing force and is reliably separated, but a sheet with weak stiffness is not sufficiently pressed by the friction member, sometimes resulting in double feeding.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a sheet feeding device in which the above-mentioned problems are solved by pressing a sheet against a friction member using a pressing means.

(d) Means for Solving the Problems The present invention has been made in view of the above-mentioned circumstances. For example, as shown with reference to FIGS. 1 and 2, A sheet comprising a body (16) and a friction member (22) that comes into contact with the leading end of the sheet (S) fed by the feeding body (16) and separates the sheets (S) one by one. In the feeding device (1), the friction member (22) is vertically inclined at a predetermined angle with respect to the sheet feeding direction, and is arranged at a predetermined distance from the feeding body (16), and pressing means (6) for pressing the sheet (S) fed by the feeding body (16) against the friction member (22);
2).

(E) Effect Based on the above-described configuration, when the sheet (S) fed by the feeding body (16) brings its tip into contact with the friction member (22), the sheet (S) is pressed by the pressing means (62). Friction member (
22). The sheet (S) is then separated while being pressed against the friction member (22) by the pressing means (62). Note that the above-mentioned symbols in parentheses are shown for reference and do not limit equivalent configurations.

(F) Embodiments Hereinafter, embodiments embodying the present invention will be described with reference to the drawings.

As shown in FIGS. 3 to 5, the sheet feeding device 1 is located on the side of a laser beam printer 2 and on the
The positioning protrusion 5 provided at the base end of the feeding device 1 is inserted into the hole 2b drilled in the printer 2. At the top of the cassette 3 there is a manual feed slot 2 for inserting manual sheets.
a has been established. Further, the sheet feeding device 1 has a paper feeding tray 6 on which thick sheets equivalent to envelopes are loaded.
The tray 6 is provided with regulating plates 7a and 7b that regulate the movement of the sheets in the width direction. Furthermore, the width regulating plate 7
A rack 9 is disposed at the bottom of the width regulating plate 7b, and a rack lO is disposed at the bottom of the width regulating plate 7b.
, 10 are meshed with a pinion gear 11, thereby allowing movement in the seat width direction.

The paper feed tray 6 is provided with a sheet presence/absence sensor 12 that detects the presence or absence of sheets. A photointerrupter 15 is turned off. Further, on the downstream side of the sensor 12, a paper feed roller 16 that feeds the sheets stacked on the paper feed tray 6 from below is rotatably supported.
Above the roller 16, there is a weight 17 carved into the side plates 19 and 20, which presses and biases the roller 16, which is a sheet.
It is supported so that it can be raised and lowered while being guided by 19a and 20a. Furthermore, in the vicinity of the weight 17, there is a leading edge regulating member 2 that regulates the leading edge of the sheets stacked on the paper feed tray 6.
1 is disposed, and the lower end of the member 21 and the downstream end of the paper feed tray 6 are spaced apart by a predetermined distance, so that sheets can be fed from this spaced apart portion. A separation pad 22 made of a high friction material such as rubber is fixed to the lower part of the tip regulating member 21 via a mounting plate 23.
6 by a predetermined distance and is inclined at a predetermined angle with respect to the sheet feeding direction. In addition, the separation pad 22
A pair of guides 25 for guiding the sheet is disposed downstream of the pair of guides 25 , and a drive roller 2 is disposed downstream of the pair of guides 25 .
A conveyance roller pair 26 consisting of a pinch roller 6a and a pinch roller 26b
is installed. Further, a bracket 27 is disposed above the roller pair 26, and a lever 30 is swingably supported on the bracket 27 and is biased to rotate counterclockwise by a spring 29. Turned on by the lever 30
- A micro switch 31 that turns off is provided. One end of the lever 30 projects from a hole 33 formed in the body 32, and when the sheet feeding device 1 is attached to the laser beam printer 2, it comes into contact with the printer 2. The microswitch 31 is turned on by swinging clockwise. Furthermore, downstream of the manual feed port 2a of the laser beam printer 2,
A sheet presence/absence sensor 34 that detects the sheet S fed from the sheet feeding device 1 is arranged, and a paper feed roller 38 that feeds the sheet S from the cassette 3 is arranged downstream of the sensor 34. ing.

Further, as shown in FIGS. 5 and 6, a motor 35 is fixed to the side plate 19, and an output gear 36 is fixed to the shaft of the motor 35. And the gear 36
meshes with the large diameter part of a two-stage gear 37 consisting of a large diameter part and a small diameter part, and the large diameter part of the gear 37 further engages with a gear 39.
The small diameter portion meshes with the gear 40.

Further, the gear 40 is connected to the drive roller 2 of the transport roller pair 26.
It meshes with a gear 41 fixed to the shaft of the motor 6a, so that the driving force from the motor 35 is transmitted to the gear 41. Further, the gear 39 is connected to a gear 43 via a spring clutch 42, and the gear 43 meshes with a drive gear 45 connected and supported to the shaft of the paper feed roller 16 via a one-way clutch. , whereby the driving force of the motor 35 is transmitted to the gear 45. A bracket 46 is disposed adjacent to the gear 45, and the shaft of the paper feed roller 16 is connected to the bracket 46 via a metal bearing 47.
As a result, the paper feed roller 16 is grounded. A lever 49 for locking the spring clutch 42 is swingably supported on the bracket 46.
One end of the spring 50 has one end formed in the bracket 46.
The lever 49 is thereby urged to swing clockwise. Further, a solenoid 51 is disposed on the bracket 46, and the solenoid 51 attracts and releases the lever 49. On the other hand, a protrusion 52 is protruded from the side plate 19 in the vicinity of the gear 40, and a spring 53 is swingably supported by the protrusion 52. One end of the spring 53 contacts the shaft of the gear 40, and the other end contacts the pinch roller 2.
The roller 26b is brought into contact with the shaft of the roller 6b and the roller 26a is
It is designed to press and bias. In addition, the side plate 19
A board 56 on which a control section 55 is mounted is disposed, and the control section 55 is connected to the motor 35 and the solenoid 51.
In addition to controlling the printer 2, it also sends and receives signals to and from the laser beam printer 2. Further, it is connected to a bracket 46 via the shaft of the side plate 1 gear 43, and the bracket 46 is grounded. Note that the reference numeral 57 in the figure is a cover for the gear 41, which is fixed to the shaft of the gear 40 with screws. Furthermore, the cover 57 is connected to the shaft of the conveyance roller 26a via a metal bearing 59, thereby grounding the conveyance roller 26a. Note that the reference numeral 60 in the figure is a cable electrically connected to the laser beam printer 2.

Further, as shown in FIGS. 9 and 10, the sheet feeding device 1 has a support plate 61 adjacent to the paper feed roller 16, and the support plate 61 is made of a material such as polyester film. A proximal end of a thin plate piece 62, which is constructed of flexible material, is fixed.

Furthermore, as shown in FIGS. 1 and 2, a low-friction sheet 65 made of a low-friction material such as a polyester sheet is attached to the upper end of the separation pad 22, and the sheet 65 is attached to the center of the separation pad 22. The length of both end portions in the sheet width direction is longer than the length of the sheet width direction, and when the fed sheet S is skewed or twisted, one end of the sheet S contacts the separation pad 22 first. This prevents a large force from being applied to the end of the pad 22. Further, the upper end portion 65a of the sheet 65 is in contact with the back surface of the lower end 21a of the tip regulating member 21, so that the sheet 65 is
Sheet S trying to get between a and separation pad 22
It is designed to guide you downward.

Since the present embodiment has the above-described configuration, when a paper feed signal is transmitted from the laser beam printer 2 to the control section 55, the control section 55 starts the motor 35. The driving force of the motor 35 is transmitted to the conveyance roller 26a via gears 36, 37 and 40, 41, and the rotation of the roller 26a also rotates the pinch roller 26b. Further, the driving force of the motor 35 is transmitted to the spring clutch 42 via the gears 36, 37, 39, but the clutch 42 is stopped by the lever 49, and the driving force is not transmitted to the paper feed roller 16. . Then, when a predetermined time (T) has elapsed since the paper feed signal was transmitted to the control unit 55, the control unit 55
turns the solenoid 51 ON and causes the lever 49 to be attracted to the solenoid 51. As a result, the spring clutch 42 enters the drive transmission state, and the rotation of the gear 39 is transmitted to the gear 43. The rotation of the gear 43 is then transmitted to the drive gear 45, and the gear 45 rotates counterclockwise. after that,
When the gear 45 rotates counterclockwise, the one-way clutch becomes connected, and the paper feed roller 16 rotates counterclockwise. Further, the sheets S loaded on the paper feed tray 6, whose leading ends are brought into contact with and aligned with the leading end regulating member 21, and whose movement toward the ends in the width direction is restricted by the width regulating plates 7a and 7b are The paper is fed from below by the paper feed roller 16. At this time, the sheets S stacked on the paper feed tray 6 are urged toward the paper feed roller 16 by the weight 17,
This increases the friction between the paper feed roller 16 and the sheet S, thereby increasing the feeding force of the paper feed roller 16. Then, the sheets St, S2, 33, and the like are fed by the paper feed roller 16.
... is in contact with the separation pad 22 and the lowest sea 1-8
．． Only the paper is fed by the feeding force of the paper feeding roller 16, which overcomes the frictional force of the separation pad 22 (see FIG. 8). At this time, the thin plate piece 62 is bent downward by the sheet Sl (
(See Figures 7 and 8). The thin plate piece 62 pushes up the sheet S2+ 83 due to the reaction force of the bending, and the sheet S2+ is pushed up. It blocks the advance of S and I and assists in the separation of Sl. Thereby, even the weak sheet S can be reliably separated. Then, the sheet S
l contacts the upper guide of the guide pair 25, and the guide pair 2
5 to the transport roller pair 26. Note that when the tip of the sheet S1 comes into contact with the upper guide, the sheet S is separated from the separation pad 22 and Ill! This reduces resistance and prevents wear of the bat 22.

Then, the sheet S1 guided to the pair of conveying rollers 26 is held and conveyed by the pair of rollers 26.

Then, after the solenoid 51 is turned on, a predetermined period of time (T
2) After that, the control unit 55 turns off the solenoid 51 to cut off the drive to the paper feed roller 16, and the sheet S is transferred from the manual feed port 2a at the top of the cassette 3 into the laser beam printer 2 by the pair of transport rollers 26. transported to. On this occasion,
The rear part of the sheet S1 is in contact with the paper feed roller 16, and the roller 16 is operated by a one-way clutch to feed the sheet S1.
There will be no resistance. Furthermore, manual feed port 2
The sheet S1 inserted into the laser beam printer 2 from a is detected by the sheet presence/absence sensor 34, and the control unit 55 that receives the signal from the sensor 34 operates the same sequence as in the manual feed mode. Then, the sheet S1 is fed to an image forming section (1'' in the figure) by a paper feed roller 38, and after an image is printed on the sheet S1, it is ejected from the body of the laser beam printer 2.

Also, a curled thick sheet S.
... are loaded, the lowest sheet S among these sheets S ... is fed to the paper feed roller 16 and comes into contact with the low friction sheet 65 at the upper end of the separation pad 2 at a larger angle than usual. However, since the sheet 65 has low friction, it slides on the sheet 65 and is guided downward. When the leading edge of the sheet S contacts the separation pad 22, the angle between the sheet S and the separation pad 22 is smaller than the normal value, and the sheet S is normally separated and fed.

In addition, in the above-mentioned embodiment, the thin plate piece 6 is used as the pressing means.
2, but the invention is not limited to this, and as shown in FIG. 9, when separating a weak sheet S, the sheet S is positioned at the solid line position and the pressing force against the separation pad 22 of the sheet S is strengthened. A roller 67 supported reversibly at the tip of a movable arm 66 may also be used. When feeding a stiff sheet, the roller 67 and arm 66 are positioned at the dashed line position to weaken the pressing force of the sheet against the separation pad 22.

Note that in the above embodiment, the paper feed roller 16 was used as the feeder, but the present invention is not limited to this, and a feed belt may also be used.

(g) As described in detail, according to the present invention, the pressing means is configured to press the sheet fed by the feeding body against the friction member, so that a weak sheet can be sufficiently pressed against the friction member. The sheet can be pressed to ensure separation of the sheets, thereby reducing double feeding.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a pressing means according to the present invention. 2 to 4 are front sectional views showing the sheet feeding device according to the present invention, and FIG. 5 is a plan view thereof. Furthermore, FIG. 6 is a front view showing the drive system. and,
7 and 8 are front sectional views showing the operation of the present invention. Moreover, FIG. 9 is a front sectional view showing another embodiment of the present invention.

Claims (1)

[Claims] 1. A sheet comprising a feeding body that feeds the sheet, and a friction member that comes into contact with the leading edge of the sheet fed by the feeding body and separates the sheets one by one. In the feeding device, the friction member is inclined vertically at a predetermined angle with respect to the sheet feeding direction, and is arranged at a predetermined distance from the feeding body, and is fed by the feeding body. A sheet feeding device, further comprising a pressing means for pressing the sheet against the friction member.