JPH11193141A - Sheet material feeding device and image processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of a trouble such as a double feed for various kinds of sheet materials and improve durability of rollers. SOLUTION: These devices have a feed roller 1 and a retard roller 2 for separating and carrying sheet material one by one by holding sheet materials, a gap sensor detecting the axis-to-axis distance of a pair of rollers 1, 2 for judging whether sheet materials are doubly fed to a holding part of the retard roller 2 or not, a torque varying means having torque limiters 53, 54 varying idling torque for rotatively carrying sheet materials in the material carrier direction by the retard roller 2 and electromagnetic clutches 59, 60 and a control means 71 controlling (ON/OFF) the electromagnetic clutches 59, 60 based on the detection signal of the gap sensor. When sheet materials are doubly fed to the holding part between the feed roller 1 and the retard roller 2, idling torque of the retard roller 2 is made large as compared with time when the sheet materials are not doubly fed.

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. 11, the sheet material feeding device 20
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. 12, the drive transmission device 213 includes a feed roller shaft 215 that supports the feed roller 206, a retard roller shaft 216 that supports 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. 11 and 12).
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. 13 shows a graph obtained by using 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.

Also, among various kinds of sheet materials, for example, sheet materials are adsorbed to each other, such as OHP sheet materials, or sheet material ends are stuck in poorly cut sheet materials. As a measure to prevent double feeding of such sheet materials, product specifications are established on the assumption that sheet materials before use are handled by hand as guidance to users. The current situation is that we have to do it.

[0014] Therefore, an object of the present invention is to provide a multi-sheet sheet without causing troubles such as double feeding.
Another object is to improve the durability of the roller.

[0015]

In order to achieve the above-mentioned object, a typical configuration of the present invention is a transport roller that is driven to rotate in a sheet material transport direction, and a fixed torque in a direction opposite to the sheet material transport direction. A separating and conveying means for pinching and separating and conveying the sheet material one by one by a reversing roller driven to rotate, and detecting whether or not the sheet material is multi-fed to a holding portion of the conveying roller and the reversing roller. Detecting means, a torque varying means for varying the idling torque for the reverse roller to follow the sheet conveying direction, and a control means for controlling the torque varying means based on a detection signal of the detecting means, When the sheet material is double-fed to the holding portion between the transport roller and the reverse roller, the idling torque of the reverse roller is made larger than when the sheet material is not double-fed.

Further, for example, one or both of the axis of the transport roller and the axis of the reverse rotation roller are pressurized and supported so as to be movable in the pressure direction with respect to one or both of the rollers. The means has a gap sensor for measuring a moving amount of the transport roller or the reverse rotation roller.

Alternatively, the detecting means has an encoder for measuring the number of revolutions of the reverse roller shaft.

Alternatively, the detecting means includes a photosensor for detecting the presence or absence of a sheet material near an upstream side of the conveyance roller and the reverse rotation roller in a sheet material conveyance direction.

Further, for example, the torque varying means includes a plurality of torque limiters having different idling torques, and a plurality of electromagnetic clutches for transmitting / releasing a driving force to / from the reverse rotation roller via the torque limiters. And the control means selectively turns on / off the electromagnetic clutch based on a detection signal of the detection means.

According to the above configuration, when a sheet material is fed twice to the holding portion between the transport roller and the reverse roller, the idling torque of the reverse roller is made larger than when the sheet material is not fed twice. Therefore, troubles such as double feeding do not occur even for a wide variety of sheet materials, and the durability of the roller can be improved, and stable separation and feeding at high speed can be performed. .

[0021]

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 FIGS. 1 to 3 and FIG. In this embodiment, a sheet material feeding device used in a copying machine as an image processing device is illustrated.

In the following description, a copying machine as an image processing apparatus will be described, and then a sheet 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 units 15 of the retard separation type,
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 moved by a registration roller pair 18 which rotates at a timing with respect to a latent image formed on a photosensitive drum 21 constituting an image forming section 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 conveyor belt 23, and is subjected to a fixing process for fixing the transferred toner image on the sheet surface.

The image processing apparatus has 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 copying mode and the multiple copying mode, the pair of inner discharge rollers 25 or the pair of switchback rollers 29 temporarily place 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 conveyed again 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 FIGS. Here, the configuration of the feeding device 15 will be described as an example, but the other feeding devices 1 will be described.
It goes without saying that the same configuration may be applied to 6, 17, and 32 as needed.

The present sheet material feeding device 15 sequentially and separately feeds the sheet materials one by one toward the above-described image forming section. The sheet material feeding device 15 is a feeding device in which a plurality of sheet materials S are stacked and stored. 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. A feed roller 1 as a conveying roller for conveying, and a sheet material S which is disposed opposite to the feed roller 1 and fed from a feeding deck 12
When there are a plurality of sheets, a pair of retard rollers 1 serving as a separating and conveying means including a retard roller 2 serving as a reverse rotation roller for rotating in a direction opposite to the rotation direction of the feed roller 1 and separating the sheet material S into one sheet. , 2 are provided.

Reference numeral 18 denotes the above-described pair of registration rollers for transporting one separated sheet material S to the image forming section. Pickup roller 3
Between the feed roller 1 and the retard roller 2 and between the feed roller 1 and the retard roller 2 and the registration roller pair.
Guides are arranged between the image forming section 18 and the registration roller pair 18 and the image forming section, respectively, so that the sheet material S is guided and conveyed.

A feed roller shaft 41 for supporting the feed roller 1, a retard roller shaft 42 for supporting the retard roller 2, and a retard roller driving shaft 43 connected to the retard roller shaft 42 are provided substantially in parallel. Have been.
In the present embodiment, the feed roller shaft 41 is supported by a side plate (not shown). On the other hand, the retard roller shaft 42
Is supported by an arm 45 that is swingable about the axis and is capable of coming into contact with and separating from the feed roller shaft 41 in parallel, and is urged by a spring 46 toward the feed roller at a constant pressure. Therefore, as shown in FIG. 1B, when a plurality of sheets are provided as shown in FIG. 1B, the sheet is fed more than when there is a single sheet material at the sandwiching portion between the feed roller 1 and the retard roller 2. The distance between the rollers 1 and the retard roller 2 becomes large. Therefore, in the present embodiment, a gap sensor 47 is disposed as detecting means for detecting the axial position of the retard roller 2, and the axial position of the retard roller 2 is measured by the gap sensor 47, so that the feed roller 1 and the retard roller It is detected whether there is one sheet material or a plurality of sheets (two or more sheets) in the holding portion 2.

Next, a configuration in which the magnitude of the idling torque of the retard roller 2 is varied when one or a plurality of sheet materials are present in the sandwiching portion between the feed roller 1 and the retard roller 2 will be described with reference to FIG.

The feed roller 1 is rotated in a direction indicated by an arrow in the figure by transmitting a rotational driving force from a main drive unit (not shown) to a feed roller shaft 41 which supports the roller, via a transmission path such as a gear. You. Also, retard roller 2
Has a configuration in which a coupling 48 is disposed between the retard roller shaft 42 and the retard roller drive shaft 43, and the driving force is reliably transmitted even when the retard roller 2 is displaced (oscillated).

A gear 49 is disposed at an end of the retard roller driving shaft 43. The gear 49 is connected to torque varying means for varying the idling torque for rotating the retard roller 2 in the sheet conveying direction. That is, the gear 49 has a torque limiter having a relatively small idling torque.
A gear 52 having a gear 54 is meshed with a gear 51 having a torque limiter 53 having a relatively large idling torque. Further, the gears 51, 52 having the torque limiters 53, 54 are respectively
The shafts 55 and 56 are provided with gears 57 and 58 having electromagnetic clutches 59 and 60, respectively.
The gears 57 and 58 having the electromagnetic clutches 59 and 60 mesh with a gear 62 that transmits a driving force from a motor 61 as a driving unit.

That is, in this embodiment, the path for transmitting the drive from the motor 61 to the retard roller drive shaft 43 is as follows.
A path for transmitting drive via the first torque limiter 53 having a large idling torque when the first electromagnetic clutch 59 is turned on;
When the second electromagnetic clutch 60 is turned on, there is a path for transmitting the drive via the second torque limiter 54 having a small idling torque.

The information about the distance between the axes of the feed roller 1 and the retard roller 2 measured by the gap sensor 47 as the detecting means described above is used as control means 71 comprising a CPU 72 and the like.
After that, the control means 71 sends a control signal (ON / OFF) to the electromagnetic clutches 59 and 60.

As described above, the torque limiters 53 and 54 having different idling torques are selectively switched by the electromagnetic clutches 59 and 60 based on the detection signal of the gap sensor 47 by the control means 71.

Next, switching control of two torque limiters having different idling torques will be described with reference to the flowchart of FIG. As shown in FIG. 3, when the copy is started, first, the second electromagnetic clutch 60 (CL2) is operated, and the second torque limiter having a relatively small idling torque is operated.
54 is operated (step S11). Then, the feed roller 1 and the retard roller 2 are moved by the pickup roller 3.
Gap sensor as soon as the sheet material is fed to the
Measure the retard roller shaft position at 47 (Step S1)
2) It is determined whether or not double feeding is being performed, that is, whether the number of sheet materials between the feed roller 1 and the retard roller 2 is only one or two or more (step S13). Here, if there is only one sheet material, the second electromagnetic clutch 60
(CL2) is operated, and the second torque limiter 54 whose idling torque is relatively small is operated (step S14).
On the other hand, when there are two or more sheet materials, the first electromagnetic clutch 59
(CL1) is ON, and the second electromagnetic clutch 60 (CL2) is O
FF is performed, and the first torque limiter 53 having a relatively large idling torque is operated to reliably separate the multi-fed sheet material (step S15).

In FIG. 3, L is the feed roller 1
L ₀ is a threshold value of the inter-axis distance when there are two or more sheet materials between the feed roller 1 and the retard roller 2.

As described above, the feed roller 1 and the retard roller are normally operated by operating the torque limiter 54 having a relatively small idling torque and operating the torque limiter 53 having a large idling torque only when the sheet material is multi-fed. 2
It is possible to achieve both the improvement of the durability and the reliable separation of the multi-fed sheet material.

In the present embodiment, the switching control of the torque limiters 53 and 54 is performed by detecting the double feed of the sheet material sent to the feed roller 1 and the retard roller 2. Since the sheet material which is easily multi-fed is known, the switching control of the torque limiters 53 and 54 may be performed according to the type of the sheet material.
For example, when a sheet material for OHP is used, the torque limiter 53 having a large idling torque is operated in advance, and the other torque limiter 54 having a small idling torque is operated when conveying other normal sheet materials. good.

[Second Embodiment] A sheet material feeding apparatus according to a second embodiment will be described in detail with reference to FIGS. In addition, since the schematic configuration of the entire apparatus is the same as that of the above-described embodiment, the following description will focus on the characteristic portions of the feeding apparatus according to the present embodiment. The same components as those of the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 4, the structure of the feeding device according to the present embodiment is substantially the same as that of the above-described first embodiment, but the pickup roller 3 feeds the sheet to the holding portion between the feed roller 1 and the retard roller 2. The method for detecting the number of sheet materials S is different as follows.

FIG. 4A is a cross-sectional view of a case where only one sheet material S has been fed to the holding portion between the feed roller 1 and the retard roller 2. In this case, as described in the first embodiment, FIG. The retard roller 2 follows the driving force of the feed roller 1 by the torque limiter 54 having a relatively small idling torque and follows the sheet roller in the sheet conveying direction, that is, rotates in the direction of the arrow opposite to the direction of the driving input.

FIG. 4B is a cross-sectional view when a plurality of sheets S are fed to the holding portion between the feed roller 1 and the retard roller 2. In this case, the retard roller 2 is driven by the feed roller 1. When the force is lost, the feed roller 1 of the sheet material S sent in a bundle to the holding portion of the two rollers is used.
Feed deck other than the top sheet in contact with
It rotates in the direction to return to 12 (the direction opposite to the sheet material conveyance direction).

Here, the sheet material double feed detecting means in the feeding device according to the present embodiment will be described with reference to FIG. As shown in FIG. 5, an encoder 73 as a detection means is installed on one end side on the same axis as the retard roller 2, the rotation number of the retard roller shaft 42 is measured by the encoder 73, and the sheet material S is sent in the downstream direction. If the sheet is rotating, there is one sheet of material in the sandwiching portion between the feed roller 1 and the retard roller 2, and if the rotation is less than a certain number of rotations (for example, less than about half the number of rotations of the feed roller 1 (including reverse rotation)) It is determined that a plurality of sheet materials have been multi-fed to the holding portion between the feed roller 1 and the retard roller 2.

The feed roller 1 and the retard roller 2
The configuration for changing the magnitude of the idling torque of the retard roller 2 when one or a plurality of sheet materials are present in the holding portion is the same as that of the above-described first embodiment, and the description is omitted.

Next, switching control of two torque limiters having different idling torques will be described with reference to the flowchart of FIG. As shown in FIG. 6, when the copy is started, first, the second electromagnetic clutch 60 (CL2) is operated, and the second torque limiter having a relatively small idling torque is operated.
54 is operated (step S21). When the sheet material reaches the holding portion between the feed roller 1 and the retard roller 2, the measurement of the rotation speed x of the retard roller shaft 42 is started by the encoder 73 (step S22). It is determined whether there is only one sheet material or two or more sheets between the retard roller 1 and the retard roller 2 (step S23). Here, when the rotation speed is equal to or higher than the predetermined rotation speed (x0), it is determined that the sheet material is not multi-fed and the second electromagnetic clutch is determined.
60 (CL2) is continuously operated, and the second torque limiter 54 whose idling torque is relatively small is operated (step S24). On the other hand, when the rotation speed of the retard roller shaft 42 is equal to or less than the predetermined rotation speed, it is determined that the sheet material has been multi-fed, and the first
The electromagnetic clutch 59 (CL1) is turned ON, and the second electromagnetic clutch 60
(CL2) is turned off, and the first torque limiter 53 having a relatively large idling torque is operated to reliably separate the multi-fed sheet material (step S25).

As described above, it is determined from the number of rotations of the retard roller shaft 42 whether only one sheet or a plurality of sheets of the sheet material is sandwiched between the feed roller 1 and the retard roller 2,
Higher double feed detection accuracy is obtained, and the separation of the sheet material by the feed roller 1 and the retard roller 2 can be reliably performed, and the durability of the feed roller 1 and the retard roller 2 can be improved.

Third Embodiment A sheet material feeding apparatus according to a third embodiment will be described in detail with reference to FIGS. In addition, since the schematic configuration of the entire apparatus is the same as that of the above-described embodiment, the following description will focus on the characteristic portions of the feeding apparatus according to the present embodiment. The same components as those of the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 7 shows the state of the second or subsequent or subsequent sheet material S 'immediately after the trailing end of the first or preceding sheet material S has passed through the holding portion between the feed roller 1 and the retard roller 2. FIG. 7A is a cross-sectional view. FIG. 7A shows that the succeeding sheet material is reliably separated from the preceding sheet material when being conveyed by the pickup roller 3, and the leading end thereof is located at a position sufficiently separated from the sandwiching portion between the feed roller 1 and the retard roller 2. FIG. 7B is a cross-sectional view showing a certain state. FIG. 7B shows that the succeeding sheet material (one or more sheets) is taken along with the preceding sheet material when being conveyed by the pickup roller 3, and the leading end thereof is connected to the feed roller 1. FIG. 5 is a cross-sectional view illustrating a state where the retard roller reaches a position near a holding portion of the retard roller.

Here, the case where the separation function of the retard roller 2 is required is in the state shown in FIG. 7B. Therefore, in the state shown in FIG. 7A, the idling torque of the retard roller 2 may be small, and only in the state shown in FIG. What is necessary is just to separate materials.

That is, in the present embodiment, the feed roller 1
And a reflection sensor (photo sensor) 74 as a detecting means is installed near the holding portion of the retard roller 2, and immediately after the preceding sheet material S has passed through the holding portion of the feed roller 1 and the retard roller 2 by the reflection sensor 74. If the following sheet material is detected, if there is no subsequent sheet material, the idling torque of the retard roller 2 is reduced when the succeeding sheet material is conveyed, and if the succeeding sheet material is present, the idling torque of the retard roller 2 is increased. good.

Here, the sheet material double feed detecting means in the feeding device according to the present embodiment will be described with reference to FIG. As shown in FIG. 8, a reflective sensor 74 for detecting the presence or absence of a sheet material is installed on a mounting table (not shown) near the upstream side in the transport direction of a sandwiching portion between the feed roller 1 and the retard roller 2, and detects a detected signal. After taking into the control means 71 comprising a CPU 72 and the like to make a determination, the control means 71 sends the electromagnetic clutch 5
Send control signal (ON / OFF) to 9,60.

The feed roller 1 and the retard roller 2
The configuration for changing the magnitude of the idling torque of the retard roller 2 when one or a plurality of sheet materials are present in the holding portion is the same as that of the above-described first embodiment, and the description is omitted.

Next, switching control of two torque limiters having different idling torques will be described with reference to the flowchart of FIG. As shown in FIG. 9, when copying is started, first, the first electromagnetic clutch 59 (CL1) is turned on to operate the first torque limiter 53 having a relatively large idling torque, and sufficient separation performance for the sheet material in the case of double feeding. Is secured (step S31). Immediately after the first sheet material has passed through the sandwiching portion between the feed roller 1 and the retard roller 2, the reflection type sensor 261 is operated (step S32), and it is determined whether or not double feeding is being performed. Is determined (step S33). Where the reflective sensor
If 74 detects that there is a sheet material, it is determined that the sheet material is multi-fed, the first electromagnetic clutch 59 (CL1) is continuously operated, and the first torque limiter having a relatively large idling torque is used. Operate 53 to reliably separate the multi-fed sheet material. On the other hand, if the reflection sensor 74 detects that there is no sheet material, it is determined that the sheet material is not multi-fed, the second electromagnetic clutch 60 (CL2) is turned on, and the first electromagnetic clutch
59 (CL1) is turned off, and the second electromagnetic clutch 60 (CL
2) is operated to operate the second torque limiter 54 whose idling torque is relatively small (step S34). Thereafter, if the copy is not completed in step S35, the process proceeds to step S32, and the above operation is repeated until the copy is completed.

As described above, by performing the switching control of the idling torque of the retard roller 2 based on the detection signal of the reflection type sensor 74, the separating ability of the multi-feed sheet material can be easily and cheaply secured, and the feed roller 1 and the retard roller 2 can be improved in durability.

[Other Embodiments] In the above embodiment,
As a configuration for varying the idling torque of the retard roller, a configuration in which two torque limiters having different magnitudes of the idling torque are switched and controlled has been exemplified. However, the present invention is not limited to this. Accordingly, a torque limiter and an electromagnetic clutch as described above may be appropriately provided, and the torque limiter may be switched and controlled. The same effect can be obtained by this configuration.

In the above-described embodiment, the configuration in which the retard roller is movably pressed against the feed roller is exemplified. However, the present invention is not limited to this. For example, the feed roller may be replaced with the retard roller. Alternatively, a configuration in which the roller is movably supported by pressure or a configuration in which both rollers are movably supported by pressure may be employed, and the same effect can be obtained by applying the present invention also to this configuration.

Further, in the above-described embodiment, a copying machine is exemplified as an image processing apparatus. However, the present invention is not limited to this. For example, other image processing apparatuses such as a scanner, a printer, and a facsimile apparatus may be used. The same effect can be obtained by applying the present invention to a sheet material feeding device used in the image processing apparatus.

Further, in the above-described embodiment, the sheet feeding apparatus detachably attached to the image processing apparatus main body is exemplified, but 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 to be recorded to the image forming unit as the processing means has been exemplified, but the present invention is not limited to this. For example, 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.

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

[0068]

As described above, according to the present invention,
When the sheet material is multi-fed to the holding portion of the conveyance roller and the reverse roller, the idling torque of the reverse roller is set to be larger than when the sheet material is not multi-fed, so that a wide variety of sheets are provided. It is possible to improve the durability of the roller without causing troubles such as double feeding of the material, and it is possible to stably separate and feed at high speed.

Further, for example, by measuring the rotation direction and the number of rotations of the reverse rotation roller by an encoder as a detecting means, it is possible to determine whether or not the sheet material is multi-fed to the holding portion between the transport roller and the reverse rotation roller. As a result, more accurate double feed detection accuracy is obtained, and sufficient separation capability and high durability performance of the transport roller and the reverse roller are obtained.

Alternatively, the presence or absence of the sheet material is measured by a photosensor as a detecting means to detect whether or not the sheet material has been multi-fed. , And high durability performance of the transport roller and the reverse roller can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of a feeding device according to a first embodiment.

FIG. 2 is a perspective view illustrating a schematic configuration of a feeding device according to the first embodiment.

FIG. 3 is a flowchart illustrating idling torque switching control of the feeding device according to the first embodiment;

FIG. 4 is a cross-sectional view illustrating a schematic configuration of a feeding device according to a second embodiment.

FIG. 5 is a perspective view illustrating a schematic configuration of a feeding device according to a second embodiment.

FIG. 6 is a flowchart illustrating idling torque switching control of a feeding device according to a second embodiment.

FIG. 7 is a sectional view showing a schematic configuration of a feeding device according to a third embodiment.

FIG. 8 is a perspective view showing a schematic configuration of a feeding device according to a third embodiment.

FIG. 9 is a flowchart illustrating idling torque switching control of the feeding device according to the third embodiment.

FIG. 10 is a schematic cross-sectional view illustrating a schematic configuration of an image processing apparatus.

FIG. 11 is a sectional view of a conventional feeding device.

FIG. 12 is a perspective view of a conventional feeding device.

FIG. 13 is a conventional feed area diagram.

[Explanation of symbols]

 S ... sheet material 1 ... feed roller 2 ... retard roller 3 ... pickup roller 11 ... image processing device main body 12 ... feeding deck 13, 14, ... feeding cassette 15, 16, 17 ... feeding device 18 ... registration roller pair 21 ... Photoreceptor drum 22… Transfer charger 23… Conveyer belt 24… Fixer 25… Inner discharge roller pair 26… Inner discharge roller pair 27… Discharge tray 28… Re-feed path 29… Switchback roller pair 30… Double-sided conveyance path 31 … Intermediate tray 32… Refeed device 41… Feed roller shaft 42… Retard roller shaft 43… Retard roller drive shaft 44… Support point 45… Arm 46… Spring 47… Gap sensor 48… Coupling 49… Gears 51, 52… Gear 53, 54 ... torque limiter 55, 56 ... shaft 57, 58 ... gear 59, 60 ... electromagnetic clutch 61 ... motor 62 ... gear 71 ... control means 72 ... CPU 73 ... encoder 74 ... reflective sensor

Claims (6)

[Claims] 1. A sheet material is sandwiched and separated one by one by a conveyance roller rotated in a sheet material conveyance direction and a reverse rotation roller rotated in a direction opposite to the sheet material conveyance direction with a constant torque. Separating / conveying means for conveying, detecting means for detecting whether or not the sheet material has been multi-fed to the holding portion of the conveying roller and the reverse rotation roller, and idling torque for rotating the reverse rotation roller in the sheet material conveyance direction. Variable torque variable means, having a control means for controlling the torque variable means based on the detection signal of the detection means, when a sheet material is double-fed to the holding portion of the transport roller and the reverse rotation roller, A sheet material feeding device, wherein the idling torque of the reverse roller is made larger than when the sheet material is not multi-fed. 2. One or both of the axis of the conveyance roller and the axis of the reverse rotation roller are pressurized and supported so as to be movable in the pressure direction with respect to one or both of the rollers. 2. The sheet feeding apparatus according to claim 1, further comprising a gap sensor for measuring a moving amount of the transport roller or the reverse roller. 3. The sheet material feeding device according to claim 1, wherein said detecting means has an encoder for measuring the number of rotations of a reverse rotation roller shaft. 4. The sheet material according to claim 1, wherein the detection means includes a photo sensor for detecting the presence or absence of a sheet material near an upstream side of the conveyance roller and the reverse rotation roller in a sheet material conveyance direction. Feeding device. 5. The torque varying means includes a plurality of torque limiters having different idling torques, and a plurality of electromagnetic clutches for transmitting / releasing a driving force to / from the reverse rotation roller via the torque limiters. 5. The sheet material feeding device according to claim 1, wherein the electromagnetic clutch is selectively turned on / off by the control unit based on a detection signal of the detection unit. 6. apparatus. 6. An image processing apparatus having processing means for processing a sheet material and feeding means for feeding the sheet material to the processing means, wherein the feeding means is used as the feeding means. Any one of
An image processing apparatus comprising the sheet material feeding device according to any one of the preceding claims.