JPH11171366A - Sheet material feeding device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably separate and feed various sheets at high speed. SOLUTION: In a sheet material feeding device provided with a pickup roller 3 for feeding a sheet material S from a feeding deck 12, a pair of retard rollers 1, 2 for separating and conveying the sheet materials S fed by the pickup roller 3 one by one, and a guide member 4 for guiding the lower surface side of the sheet material S to be fed from the pickup roller 3 to a pair of retard rollers 1, 2, a roller 5 to be rotated by being brought into contact with the lower surface of the sheet material S to be fed from the pickup roller 3 to a pair of retard rollers 1, 2 is provided, and this roller 5 is arranged above the guide member 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet material feeding apparatus for sequentially separating and feeding sheet materials one by one, and more particularly, to a sheet material feeding apparatus used in an image processing apparatus such as a printer or a copying machine. It concerns the device.

[0002]

2. Description of the Related Art Conventionally, as a sheet material feeding device used in an image processing apparatus such as a copying machine, there is, for example, a sheet material feeding device 201 as shown in FIG. This sheet material feeding device 201 includes a processing unit (for example, a processing unit of an image processing device such as a copying machine).
The sheet materials 202 are sequentially supplied one by one to an image forming unit of a copying machine. As shown in FIG.
1 is a pickup roller 205 for feeding the uppermost sheet material 202 one by one from a sheet material storage device 203 in which a plurality of sheet materials 202 are stacked and stored on a loading table (not shown); The feed roller 20 transports the sheet material 202 fed from the sheet material storage device 203 toward the processing section (the direction of arrow b in the drawing).
6, when there are a plurality of sheet materials 202 which are arranged opposite to the feed roller 206 and are fed from the sheet material storage device 203, the sheet material 202 is rotated in the direction opposite to the rotation direction of the feed roller 206 to form one sheet material. There is provided a retard roller 207 for separating the sheet material 202 into two, and a conveying roller pair 209 for conveying one separated sheet material 202 to the processing section.

A guide 211 is disposed in a sheet material passage area 210 between the pickup roller 205, the feed roller 206, and the retard roller 207.
Guides 212 are arranged between the 206 and the retard roller 207 and the transport roller pair 209 and between the transport roller pair 209 and the processing unit, and the sheet material 202 is guided and transported respectively.

The feed roller 206 and the retard roller 207 are driven by a drive transmission device 213 shown in FIG. As shown in FIG. 4, the drive transmission device 213 includes a feed roller shaft 215 for supporting the feed roller 206, a retard roller shaft 216 for supporting the retard roller 207, and a retard roller connected to the retard roller shaft 216. The drive shaft 217 is provided substantially in parallel. Retard roller shaft
Reference numeral 216 is supported by a swingable support member (not shown) and can be brought into and away from the feed roller shaft 215 in parallel. A coupling 219 and a torque limiter are provided between the retard roller shaft 216 and the retard roller drive shaft 217.
220 are located. Further, a driving force transmitted from a main drive unit (not shown) via a drive input belt 221 is applied to an end of the feed roller shaft 215.
5 is provided with an electromagnetic clutch 222. Between the feed roller shaft 215 and the retard roller shaft 217, a retard drive belt 223 that transmits the rotational driving force transmitted to the feed roller shaft 215 to the retard roller drive shaft 217 is wound. In addition, coupling 219
Is for transmitting the drive from the retard roller drive shaft 217 to the retard roller shaft 216 even if the retard roller 207 is displaced.

The driving of the feed roller 206 and the retard roller 207 by the drive transmission device 213 will be described. Rotational driving force provided from a main drive unit (not shown) is transmitted to a drive input belt 221 and input to a pulley 225 provided on an armature portion of an electromagnetic clutch 222 that is ON-OFF controlled in accordance with a sheet feeding timing. Here, since the feed roller shaft 215, the retard roller drive shaft 217, and the retard roller shaft 216, which rotate integrally with the rotor portion of the electromagnetic clutch 222, are connected by the retard drive belt 223, the feed roller shaft 215 and the retard roller shaft 216 are connected. Further, the retard roller drive shaft 217 rotates in the same direction, and the feed roller 206 and the retard roller 207 are rotationally driven in synchronization with the sheet feeding timing ON.

[0006] The sheet material 202 is driven by the drive transmission device 213.
Roller 207 is fed one by one in the feeding direction (the direction of arrow b shown in FIGS. 3 and 4).
The torque limiter 220 idles due to the frictional force between the sheet 206 and the sheet member 202, and rotates in a direction (feeding direction) opposite to the driving rotation direction of the retard roller 217. Further, when a plurality of sheet materials 202 are fed, the plurality of sheet materials 202 are not affected by the frictional force between the retard roller 207 and the sheet material 202.
Since the frictional force between them is small, the torque limiter 220 does not run idle, and the retard roller 207 is driven by the retard roller drive shaft 21.
7 rotates in the same direction as the rotational drive direction (the direction opposite to the feeding direction). As a result, the feed roller 206 side of the plurality of fed sheet materials 202, that is, the uppermost sheet material 202 and the other sheet materials 202 are separated, and the multi-feed of the sheet materials 202 to the processing unit is performed. To prevent it.

Next, a description will be given of a theoretical formula that satisfies the conditions for feeding and separating the sheet material 202 by the sheet material feeding device 201 having the above-described configuration. In the following equation, μ _AP is the friction coefficient between the pickup roller 205 and the sheet material 202, μ _BP is the friction coefficient between the feed roller 206 and the sheet material 202, μ _CP is the friction coefficient between the retard roller 207 and the sheet material 202, μ _APP is the coefficient of friction between the pick-up roller 205 and the sheet material 202 under the pressurizing section, and μ _BPP is the feed roller 206 and the retard roller 20.
7, N is the pressure of the retard roller 207, T is the idling torque of the torque limiter 220, r is the radius of the retard roller 207, and W is the pressure of the pickup roller 205. .

[0008] _{N> T / rμ BP + (} μ APP -μ AP) W / μ BP ... (1) N <T / rμ BPP -2μ APP W / μ BPP ... (2) N <T / rμ CP ... ( 3)

The above equation (1) satisfies the feeding condition, (2) satisfies the separation condition, and (3) satisfies the revolving condition of the retard roller 207. If the same sheet material is used in the above equation, the friction coefficient of each roller pressing portion does not vary so much. Therefore, the friction coefficient is given by μ _APP ≒ μ _BPP
= Μ _PP , the above equations (1) and (2) become the following equations (4) and (5), respectively.

N> T / rμ _BP + (μ _PP −μ _AP ) W / μ _BP (4) N <T / r μ _PP -2W (5)

Here, the relations of the above equations (3), (4) and (5) are expressed by the pressing force N of the retard roller 207 and the torque limiter 22.
FIG. 5 is a graph showing the idling torque T of 0 as a parameter. In the figure, a hatched portion is a feeding area in which the sheet feeding as described above is properly performed. In order to enlarge this feeding area (shaded area), increase the coefficient of friction between each roller and the sheet material or use a pickup roller.
It is necessary to reduce the pressurizing force of the roller 205 and the feed condition is set under the condition of increasing both the pressing force N of the retard roller 207 and the idling torque T of the torque limiter 220 (upper right direction in the figure). It can be understood that the feeding area (shaded area) becomes wider. However, if the idling torque of the torque limiter 220 is excessively increased, the load torque in driving the roller increases, so that the proper feeding area (shaded area)
(The upper right limit in the figure) is also subject to some restrictions.

[0012]

With the recent increase in the speed of image processing apparatuses and diversification of sheet materials, it has become difficult to set an almighty feeding area. That is, it has become difficult to achieve both the prevention of double feeding of various sheet materials beforehand and the sufficient securing of the durability of the feed roller and the retard roller. Specifically, in order to prevent double feed, the idling torque of the torque limiter may be increased or the pressing force of the retard roller may be reduced, but if this is turned over, this configuration is equivalent to the feed roller and the retard roller. It shifts to shorten the durability.

When the uppermost sheet material 202 is fed by the pickup roller 205 one by one from the sheet material storage device 203, not only one sheet but also a plurality of sheets at the same time. There is a sheet material having a strong property of being fed, and the conditions for preventing the double feed described above are strict in order to increase the speed.

The simultaneous feeding of a plurality of sheets by the pick-up roller 205 occurs because the coefficient of friction on the surface of the sheet material is not uniform or the cut state of the edge of the sheet material is not uniform. . For example, if the coefficient of friction between the sheet materials suddenly becomes small between the fifth and sixth sheet materials from the uppermost layer, not only the uppermost sheet material but also 5 A sheet (from the top layer to the fifth sheet) may be fed at a time. Further, if the end of the sheet material is not cut flat and burrs remain, the burrs are caught and a plurality of sheet materials are fed.

It has been confirmed that these phenomena become more remarkable as the rotation speed of the pickup roller 205 increases. Then, the plurality of sheet materials fed in this way are separated by the above-described operation between the feed roller 206 and the retard roller 207, which are the above-described separation units.

Further, when the speed is increased, for a certain kind of sheet material, the probability that a plurality of sheet materials are fed in a bundle when the pickup roller 205 feeds the sheet material and the number of the sheet material bundle at that time are reduced. It has been experimentally confirmed that both increase.

Furthermore, when the number of sheet bundles entering between the feed roller 206 and the retard roller 207 is large, what is important is how efficiently the lower sheet material other than the uppermost sheet material can be recovered. That is, if there is a factor that hinders the action of returning the lower sheet material, the above-mentioned expression (5) is not satisfied.

For example, as shown in FIG. 3, when the pickup roller 205 feeds a plurality of sheet materials 202 in a bundle and then separates from the upper surface of the sheet material bundle, the lower surface of the sheet material bundle When contacting the upper end 204a of the guide member 204 constituting the storage device 203, the retard roller
The action of returning the lower sheet material other than the uppermost sheet material by 207 causes the lower surface of the sheet material bundle and the upper end of the guide member 204 to return.
The probability of occurrence of double feed is increased because of the interference caused by friction between the feeder 204a.

As a measure for preventing this,
Simply changing the position of the upper end 204a of the guide member 204 to a lower position lowers the function of pre-separating the sheet material fed by the pick-up roller 205, and thus cannot be said to be advantageous.

As described above, as the speed is increased, for a certain type of sheet material, the probability that the sheet material is fed in a bundle and the number of sheets in the bundle at that time are both increased. Since the frictional force acting between the lower sheet material other than the upper sheet material and the upper end 204a of the guide member 204 on the sheet material feeding direction exit side of the sheet material storage device 203 increases,
This is a factor that hinders the action of returning the lower sheet material, and the above-mentioned expression (5) is no longer satisfied, and the feeding area (shaded area) shown in FIG. 5 is narrowed.

An object of the present invention is to enable high-speed and stable separation and feeding of various sheet materials.

[0022]

A typical configuration of the present invention for achieving the above object is a feeding means for feeding a sheet material from a sheet material storing means, and a sheet fed by the feeding means. Separating and conveying means for separating and conveying the sheet material one by one;
A guide member for guiding a lower surface side of the sheet material fed from the feeding means to the separation / conveyance means, wherein the sheet material fed from the feeding means to the separation / conveyance means. A rotating body that rotates in contact with the lower surface of the guide member, and the rotating body is disposed above the guide member.

Further, an outer peripheral surface of the rotating body projects upward from a guide surface or an end of the guide member.

For example, the guide member has a function of preliminarily separating the sheet material fed by the feeding means at the exit side of the sheet material storing means in the sheet material feeding direction.

According to the above construction, the rotating body which rotates while contacting the lower surface of the sheet material fed from the feeding means to the separation / conveying means is fed from the feeding means to the separation / conveying means. Is arranged above the guide member for guiding the lower surface side of the sheet material to be fed, even if a plurality of sheet materials are fed in a bundle due to high speed, the lower part of the sheet material bundle is Since it is in contact with the rotating body rotatably supported above the member, it does not hinder the operation of returning the lower sheet material by the separating and conveying means. That is, even if the sheet material is fed in a bundle when the speed is increased, the function of returning the sheet material is not hindered, so that the separation and feeding can be performed at high speed and stably with respect to various sheet materials.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a sheet feeding apparatus to which the present invention is applied will be specifically described below with reference to the drawings. In the following description, a sheet material feeding device used in an image processing device is exemplified.

[First Embodiment] A sheet material feeding apparatus according to a first embodiment will be described in detail with reference to the drawings.
In this embodiment, a sheet material feeding device used in a copying machine as an image processing device is illustrated.

In the order of the following description, a copying machine as an image processing apparatus will be described, and then a sheet material feeding apparatus will be described.

First, a schematic configuration of the image processing apparatus will be described with reference to FIG. The image processing apparatus includes, as sheet material storage means, a feeding deck 12 on which a large amount of sheet materials S are stacked and stored on one side of the image processing apparatus main body 11, and a predetermined amount in a lower portion inside the image processing apparatus main body 11. Are provided with a plurality of feed cassettes 13 and 14 in which the sheet materials S are stacked and stored.

The feeding deck 12 serving as a feeding unit for feeding the sheet material S, and the feeding devices 15 of the retard separation system,
16, 17 are provided. This feeding device will be described later in detail.

When the sheet material S in the feeding deck 12 and the feeding cassettes 13 and 14 is fed by the respective feeding devices 15, 16 and 17, first, the registration roller pair stopped rotating.
It is sent to 18, where the skew state is corrected.

Next, the photosensitive drum 21 and the transfer charger 22 are connected to each other by a registration roller pair 18 which rotates at a timing relative to a latent image formed on the photosensitive drum 21 constituting an image forming unit as a processing means. The toner image on the photosensitive drum 21 is transferred here.

Thereafter, the sheet material S is sent to the fixing device 24 by the transport belt 23, and a fixing process for fixing the transferred toner image on the sheet surface is performed.

The image processing apparatus is provided with a duplex copying mode for performing duplex copying on the sheet material S and a multiplex copying mode for performing multiple copying. In the normal copying mode (single-side copying mode), the sheet after the fixing process is performed. The material S is discharged onto a discharge tray 27 outside the machine by a pair of inner discharge rollers 26.

In the case of the double-sided copy mode and the multiple copy mode, the pair of inner discharge rollers 25 or the pair of switchback rollers 29 temporarily places the sheet on the intermediate tray 31 via the re-feeding path 28 and the double-sided conveying path 30. It is loaded and stored.

Then, the sheet material S stored on the intermediate tray 31 is again conveyed to the registration roller pair 18 for image formation by the re-feeding device 32, and thereafter discharged out of the apparatus through the same process as for one-sided copying. Is done.

Next, the feeding devices 15, 16, 17 and the re-feeding device 32 as sheet feeding devices to which the present invention is applied will be described with reference to FIG. Here, the configuration of the feeding device 15 will be described as an example, but other feeding devices 16, 17, and
Needless to say, the same configuration may be applied to 32 as needed.

The present sheet material feeding device 15 sequentially separates and feeds the sheet materials one by one toward the above-mentioned image forming section. A pickup roller 3 as a feeding means for feeding the uppermost sheet material S one by one from the deck 12, and the sheet material S fed from the feeding deck 12 by the pickup roller 3 into the image processing apparatus main body. When there are a plurality of feed rollers 1 to be conveyed and a plurality of sheets S which are disposed to face the feed rollers 1 and are fed from the feed deck 12, the sheet materials S rotate in the direction opposite to the rotation direction of the feed rollers 1 to form one sheet. And a retard roller pair 2 for separating the sheet material S into the sheet material S.

In FIG. 1, a is a feed roller 1
, The rotation direction of the pickup roller 3, b, the conveyance direction of the sheet material, and c, the rotation direction of the retard roller 2.

In FIG. 1, reference numeral 4 denotes a guide member which guides the lower surface of the sheet material S fed from the pickup roller 3 to the pair of retard rollers 1 and 2. In the present embodiment, the guide member 4
The sheet also serves to separate the sheet material S fed by the pickup roller 3 into one or several sheets in advance at the sheet feeding direction exit side of the feeding deck 12.

Further, in FIG. 1, reference numeral 5 denotes a roller as a rotating body, which is rotatably supported about a shaft 6, and which is connected from the pickup roller 3 to the retard roller pair 1, 1.
The sheet S is fed and rotated following the lower surface of the sheet S fed to the sheet feeding device 2. The roller 5 is arranged so that its outer peripheral surface protrudes upward from the upper end 4 a of the guide member 4.

Here, the operation of the rollers 5 during feeding of the sheet feeding apparatus 15 will be described. That is, when the uppermost sheet material S of the feeding deck 12 is fed to the nip portion of the retard roller pairs 1 and 2 by the pickup roller 3, not only the uppermost layer but also a plurality of sheet materials S are fed. Even in this case, since the lower part of the bundle of sheet materials S is in contact with the roller 5 rotatably supported above the upper end 4a of the guide member 4, the lower part of the bundle of sheet materials S The contact with the upper end 4a of the member 4 can be prevented, and the operation of returning the lower sheet material other than the uppermost layer by the retard roller 2 is not hindered.

Thus, even if the number of bundles of the sheet material S entering the nip portion of the retard roller pair 1 and 2 is increased due to the speeding-up, an effect of stably returning the bundle is obtained. Fast and stable separation and feeding of various sheet materials can be performed.

[Other Embodiments] In the above-described embodiment, a copying machine has been described as an example of an image processing apparatus. However, the present invention is not limited to this.
Another image processing apparatus such as a facsimile apparatus may be used, and similar effects can be obtained by applying the present invention to a sheet feeding apparatus used in the image processing apparatus.

In the above-described embodiment, the sheet feeding apparatus detachably attached to the image processing apparatus main body is exemplified. However, the present invention is not limited to this.
For example, a sheet feeding device integrally provided in the image processing apparatus may be used, and similar effects can be obtained by applying the present invention to the sheet feeding device.

Further, in the above-described embodiment, the sheet material feeding apparatus for feeding the sheet material such as the recording paper as the recording target to the image forming unit as the processing means has been exemplified, but the present invention is not limited to this. However, the same effect can be obtained by applying the present invention to a sheet material feeding device that feeds a sheet material such as a document to be read to a reading unit serving as a processing unit.

Further, in the above-described embodiment, the electrophotographic method is exemplified as the recording method. However, the recording method is not limited to this, and another recording method such as an ink jet method may be used.

[0048]

As described above, according to the present invention,
The rotating body that rotates in contact with the lower surface of the sheet material fed from the feeding means to the separation / conveyance means guides the lower surface side of the sheet material fed from the feeding means to the separation / conveyance means. Since it is arranged above the guide member, even when a plurality of sheet materials are fed in a bundle due to high speed, the lower portion of the sheet material bundle is rotatably supported above the guide member. Since it is in contact with the rotated body, the operation of returning the lower sheet material by the separating and conveying means is not hindered. That is, even if the number of sheet material bundles fed to the separation / conveying means increases with an increase in speed, an effect of stably returning the sheet material can be obtained. Stable separation and feeding can be performed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of a feeding device according to the present invention.

FIG. 2 is a pillow-type cross-sectional view illustrating a schematic configuration of an image processing apparatus.

FIG. 3 is a sectional view of a conventional feeding device.

FIG. 4 is a perspective view of a conventional feeding device.

FIG. 5 is a conventional feed area diagram.

[Explanation of symbols]

 S ... sheet material 1 ... feed roller 2 ... retard roller 3 ... pickup roller 4 ... guide member 4a ... upper end 5 ... roller 6 ... shaft 11 ... image processing apparatus body 12 ... feeding decks 13, 14 ... feeding cassettes 15, 16 , 17: feeding device 18: registration roller pair 21: photosensitive drum 22: transfer charger 23: transport belt 24: fixing device 25: internal discharge roller pair 26: internal discharge roller pair 27: discharge tray 28: re-feed Path 29: Switchback roller pair 30: Double-sided conveyance path 31: Intermediate tray 32: Refeeding device

Claims (4)

[Claims] A feeding unit configured to feed the sheet material from the sheet material storing unit; a separating and conveying unit configured to separate and convey the sheet material fed by the feeding unit one by one; A sheet member feeding device having a guide member for guiding a lower surface side of the sheet material fed to the separating / conveying means, wherein the sheet material is in contact with the lower surface of the sheet material fed from the feeding means to the separating / conveying means. A sheet feeding device, comprising: a rotating body that rotates; and the rotating body disposed above the guide member. 2. The sheet feeding device according to claim 1, wherein an outer peripheral surface of the rotating body protrudes above a guide surface or an end of the guide member. 3. The sheet member according to claim 1, wherein the guide member has a function of preliminarily separating the sheet material fed by the feeding means at the sheet material feeding direction exit side of the sheet material storage means. Or the sheet material feeding device according to claim 2. 4. An image processing apparatus comprising: a processing unit for processing a sheet material; and a feeding unit for feeding the sheet material to the processing unit, wherein the feeding unit is used as the feeding unit. Any one of
An image processing apparatus comprising the sheet material feeding device according to any one of the preceding claims.