JPH07157135A - Sheet feed device - Google Patents

Abstract

PURPOSE:To provide a paper feed route linearly without causing deterioration of separating function and occurrence of noise even if a paper sheet is pulled out by a frictional member and paper feed roller and fed by a pair of feed rollers. CONSTITUTION:A guide member 7 is installed on an upper guide plate 8 between a sheet feed roller 2 and a pair of feed rollers 5. Also the lowermost end of the guide surface of the guide member 7 is formed so that it is located slightly lower than a tangential line A-C extending to a pair of feed rollers 5 side at a contact point A of a paper feed roller 2 with a frictional member 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding rotary member for feeding the lowermost sheet or the uppermost sheet of stacked sheets, and a friction member which is pressed against the sheet feeding rotary member to prevent double feeding. A feed roller pair provided on the downstream side of the feed roller in the sheet feed direction, and when the sheet fed to the feed roller pair is pinched, the drive of the feed roller is stopped. The present invention relates to a sheet feeding / conveying device that conveys a sheet by the conveying force of the conveying roller pair.

[0002]

2. Description of the Related Art A sheet feeding / conveying apparatus of the above type is known and is attached to a printer, a copying machine, a facsimile, a printing machine or the like. FIG. 6 shows a conventional example of this type of sheet feeding and conveying device.

In FIG. 6, a friction member 1 is pressed against a paper feed roller 2 by a pressurizing means (not shown), a pickup roller 3 is provided on the upstream side in the paper feed direction, and a conveyance roller is provided on the downstream side. Pair 5 is provided. The stacked sheets 6 to be fed are pressed against the pickup roller 3 by the pressure plate 4. Here, according to the paper feed command, the pickup roller 3 and the paper feed roller 2 are rotationally driven in the counterclockwise direction, and the paper 6 is separated by the friction member 1 and conveyed to the conveying roller pair 5. After the sheet 6 reaches the conveying roller, the driving of the pickup roller 3 and the sheet feeding roller 2 is stopped, and the sheet 6 is pulled out while being sandwiched between the friction member 1 and the sheet feeding roller 2. 5 is conveyed.

As shown in FIG. 7, the friction member 1 is pressed against the paper feed roller 2 on the side of the conveying roller pair 5 with respect to the uppermost point D of the paper feed roller 2. That is, a tangent line A− extending at the contact point A between the paper feed roller 2 and the friction member 1 and extending toward the conveyance roller pair 5
When the angle formed by C and the straight line AB that connects the nip B of the transport roller pair 5 with the contact point A as the starting point is θ, the angle guide plate θ has a clockwise direction in the drawing with the tangent line AC as a reference. Further, the friction member 1 is pressed against the paper feed roller 2. With this configuration, the paper 6 stopped by the friction member 1 to be fed in the next paper feed is reliably fed by the paper feed roller 2.

As described above, when the sheet 6 is pulled and conveyed by the conveying roller pair 5, the sheet 6 is pulled between the uppermost point D of the sheet feeding roller 2 and the nip B of the conveying roller pair 5 due to the load for pulling out the sheet 6. Since the friction member 1 tries to pass on the connecting straight line D-B, the friction member 1 receives the force of being lifted by the paper 6 to the straight line D-B separated from the paper feed roller 2.

As a result, there is a problem that the friction member 1 shifts to a position different from the normal position as shown by the chain line in FIG. 7, the separation performance deteriorates, and double feeding occurs. Further, since the friction member 1 is rubbed against the paper 6 while floating from the paper feed roller 2, there is also a problem that noise due to sliding of the paper 6 is likely to occur.

In order to solve such a problem, the conventional method shown in FIG.
As shown in (1), the traveling direction of the paper 6 from the paper feed roller 2 is changed obliquely downward, and the conveying roller pair 5 is arranged so that the angle θ becomes zero or negative.

[0008]

However, in the above-described conventional paper feeding / conveying apparatus, the paper feeding / conveying path cannot be linearly provided, and the size and design flexibility of the apparatus are greatly limited. It was

The present invention solves the above-mentioned conventional problems and does not cause deterioration of separation performance and noise even when a sheet is conveyed by a pair of conveying rollers so that the sheet is pulled out by a friction member and a sheet feeding roller. An object of the present invention is to provide a paper feeding / conveying device capable of linearly providing a paper feeding / conveying path.

[0010]

In order to achieve the above object, the present invention provides a sheet feeding rotary member for feeding the lowermost sheet or the uppermost sheet of stacked sheets, and a pressing contact with the sheet feeding rotary member. A friction member for preventing double feeding and a conveying roller pair provided on the downstream side of the sheet feeding rotating body in the sheet conveying direction, and when the sheet fed to the conveying roller pair is pinched, In a paper feeding / conveying device for stopping the driving of the paper feeding rotator and for conveying the paper by the conveying force of the conveying roller pair, in the tangential direction of the contact point of the paper feeding rotator of the friction member, or the paper feeding from the contact point. A guide member for guiding the sheet in a direction closer to the center of the rotating body is provided between the sheet feeding rotating body and the conveying roller pair.

Further, in order to achieve the above object, the present invention is characterized in that the guide member is a rotatable roller.

Further, in order to achieve the above-mentioned object, the present invention is configured such that the width of the guide member is longer than the width of the sheet feeding rotary member and the center of the sheet feeding rotary member in the width direction is set. The feature is that they are arranged symmetrically.

Further, in order to achieve the above object, the present invention is characterized in that the widthwise end portion of the guide member is chamfered.

[0014]

According to the above construction, the guide member for guiding the sheet in the direction substantially tangential to the contact point of the paper feed rotary member of the friction member or in the direction closer to the center of the paper feed rotary member from the contact point is provided.
Since it is provided between the feed roller and the feed roller pair, even if the feed roller pair pulls the paper out of the friction member and the feed roller, the guide member does not cause the friction member to float. Therefore, it is possible to prevent deterioration of the separation performance and generation of abnormal noise.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram of a sheet feeding and conveying device according to the present invention, and corresponds to FIG. 7 described above, and the same members are denoted by the same reference numerals.

In FIG. 1, a guide member 7 is provided on the upper guide plate 8 between the paper feed roller 2 and the conveying roller pair 5. Further, the lower guide plate 9 is arranged at a position lowered according to the guide member 7. The lowermost end of the guide surface of the guide member 7 is a contact point A between the paper feed roller 2 and the friction member 1.
Is formed so as to be slightly lower than the position of the guide member 7 of the tangent line A-C extending toward the conveying roller pair 5 side by a distance. As a result, the guide member 7 guides the paper 6 from the contact point A between the paper feed roller 2 and the friction member 1 toward the center of the paper feed roller 2. That is, the guide member 7 guides the sheet 6 diagonally downward in the tangential line A-C direction.

In the sheet feeding / conveying apparatus having the above structure, when the leading end of the sheet 6 to be fed passes through the sheet feeding roller 2 and the friction member 1, the lowermost end of the guide surface of the guide member 7 rubs against the sheet feeding roller 2. Since the contact point A of the member 1 is formed slightly below the tangent line A-C extending toward the conveying roller pair 5 side, the guide member 7 guides it obliquely downward. When the sheet 6 is guided by the lower guide plate 9 and the guide member 7 as shown by the chain line in FIG.
Guided to the nip. When the paper 6 is clamped by the transport roller pair 5, the driving of the paper feed roller 2 is stopped and the transport roller pair 5 is stopped.
It is transported with the transport force of. At this time, since the paper 6 is conveyed while slidingly contacting the lowermost end of the guide member 7, the paper 6 is pulled out substantially in the tangential line A-C direction between the paper feed roller 2 and the friction member 1. Therefore, no force for floating is applied to the friction member 1, and noise is prevented from being generated.

FIG. 2 shows another embodiment of the present invention, in which the guide member 7 is constituted by a guide roller 7 which is rotatable around an axis orthogonal to the sheet conveying direction. Guide roller 7
The lowermost end of the guide surface of the paper feed roller 2 and the friction member 1
At the contact point A of the tangent line A-C extending toward the pair of transport rollers 5
It is formed so as to be slightly lower than the position of the guide member 7 by 1.

According to this structure, the same effect as that of the above-described embodiment can be obtained, and when the sheet 6 is pulled by the conveying roller pair 5 and slidably contacts the guide roller 7, the guide roller 7 rotates. Therefore, the load on the sheet conveyance is reduced.

FIG. 3 shows another embodiment of the present invention, in which the guide member 7 has a width 2 which is longer than the width of the paper feed roller 2.
It is formed to be longer by b and is arranged symmetrically with respect to the center of the paper feed roller 2 in the width direction. That is, the guide member 7 is formed longer than each end of the paper feed roller 2 by the length b.

According to this structure, the paper 6 is the pair of transport rollers 5.
When pulled by the guide member 7, the guide member 7 receives the paper in a larger area than the paper feed roller 2, so that the force that the paper 6 receives from the guide member 7 is dispersed. As a result, damage when the paper 6 is handled by the guide member 7 is reduced, and the paper 6
Wrinkles can be prevented.

Further, in the present invention, as shown in FIG. 4, the widthwise end portion of the guide member 7 is chamfered to form a taper with an angle ψ, and the corner portion is further rounded.

According to this structure, the paper 6 is the pair of transport rollers 5
When the sheet 6 is pulled by the guide member 7, the step between the portion that is engaged with the guide member 7 and the portion that is separated from the guide member 7 can be reduced, and the damage caused by the step when the sheet 6 is handled by the guide member 7 is reduced, and the wrinkle of the sheet 6 is reduced. Etc. can be prevented.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and various modifications can be made. For example, in the above embodiment, the paper feeding / conveying device that sequentially feeds the lowermost paper of the stacked sheets has been described, but as shown in FIG. In FIG. 5, reference numeral 11 is a friction member, 12 is a paper feed roller, 15 is a pair of conveying rollers and 17
Is a guide member. Further, the present invention can be applied to a sheet feeding and conveying device that does not use a pickup roller.

[0025]

According to the first aspect of the present invention, the guide member for guiding the sheet in the direction substantially tangential to the contact point of the paper feed rotary member of the friction member or in the direction closer to the center of the paper feed rotary member from the contact point. Is provided between the feed roller and the feed roller pair, the guide member prevents the friction member from floating even if the feed roller pair pulls the paper from the friction member and the feed roller. Since it is transported, it is possible to prevent deterioration of separation performance and generation of abnormal noise.

According to the second aspect of the present invention, the same effect as described above can be obtained, and the load on the sheet conveyance when the sheet is pulled by the pair of conveying rollers and slidably contacts the guide rotating body can be reduced. .

According to the third aspect of the invention, when the paper is pulled by the pair of transport rollers, the guide member can receive the paper in a larger area than the paper feed rotating member, so that the force received by the paper from the guide member is dispersed. Since damage when the paper is handled by the guide member is reduced, it is possible to prevent the paper from wrinkling or the like.

According to the structure of claim 4, when the sheet is pulled by the pair of conveying rollers, the step between the portion applied to the guide member and the portion removed from the guide member can be made small.
Damage when the paper is handled by the guide member is reduced, and wrinkles and the like can be prevented from occurring on the paper.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a sheet feeding / conveying device according to the present invention.

FIG. 2 is a schematic configuration diagram showing another embodiment of the present invention.

FIG. 3 is a configuration layout diagram showing still another embodiment of the present invention.

FIG. 4 is an explanatory view showing a modification of the guide member of FIG.

FIG. 5 is a schematic configuration diagram showing an application example of a sheet feeding and conveying device according to the present invention.

FIG. 6 is an overall schematic configuration diagram of a conventional paper feeding and conveying device.

FIG. 7 is a schematic configuration diagram of a conventional paper feeding and conveying device.

FIG. 8 is a schematic configuration diagram of a conventional paper feeding and conveying device.

[Explanation of symbols]

 2,12 Paper feeding roller 5,15 Conveying roller pair 6 Paper 7,17 Guide member

Claims (4)

[Claims] 1. A paper feed rotator for feeding the lowermost paper or the uppermost paper of the stacked papers, and a pressure contact with the paper feed rotator,
It has a friction member for preventing double feeding and a conveying roller pair provided on the downstream side of the sheet feeding rotating member in the sheet conveying direction. When the sheet fed to the conveying roller pair is pinched, In a paper feeding and conveying device for stopping the driving of the paper rotator and conveying the paper by the conveying force of the conveying roller pair, in the tangential direction at the contact point of the paper feed rotator of the friction member or from the contact point to the paper feed rotation. A sheet feeding / conveying device, characterized in that a guide member for guiding the sheet in a direction closer to the center of the body is provided between the sheet feeding rotating body and the pair of conveying rollers. 2. The paper feeding / conveying device according to claim 1, wherein the guide member is a rotatable roller. 3. The sheet feeding / conveying apparatus according to claim 1, wherein the width of the guide member is formed to be longer than the width of the sheet feeding rotating body, and the width of the sheet feeding rotating body is centered in the width direction. A sheet feeding / conveying device, which is symmetrically arranged with respect to the sheet feeding / conveying device. 4. The sheet feeding / conveying apparatus according to claim 3, wherein the widthwise end portion of the guide member is chamfered.