JP3545828B2 - Paper separation device - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a sheet separation device.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a printing machine and the like, there are many types of sheet feeding / separating apparatuses for preventing double feeding of sheets.
Among these, those using a friction member have a concave shape, that is, a shape along the outer periphery of the paper feed roller, and are intended to perform separation in a longer range, but depending on the paper, In some cases, the tip could not be completely separated, and even when separated, the tip was sometimes broken.
[0003]
The friction member is not simply pressed against the paper feed roller as described above, but when necessary, that is, a plurality of sheets are separated between the paper feed roller and the friction member (in this case, the reverse roller), that is, separated. The FRR is widely known in which the reverse roller is continuously reversely rotated only when the vehicle enters the section.
[0004]
In this FRR method, a plurality of sheets are pushed back one after another in a direction opposite to the sheet feeding direction because the reverse roller is continuously rotated in reverse, and when the remaining sheet becomes one, the reverse roller prevents reverse rotation by the sheet. Then, the sheet is turned forward and the sheet is fed only.
[0005]
Although the FRR method has excellent sheet separation performance, generally, in medium-to-high-speed sheet feeding such as a printing machine, there is a case where a multi-fed sheet cannot be completely returned and is fed as it is. In addition, there are problems in terms of cost and durability, and there are circumstances in which it is difficult to adopt the technology.
[0006]
[Problems to be solved by the invention]
As described above, in the conventional paper feed / separation apparatus for preventing double feed of paper, the separation condition is theoretically required only when two papers enter between the paper feed roller and the friction member. Is satisfied, and three or more sheets enter the separation unit at the same time, there is a problem that it is difficult to surely separate one sheet at a time, and there is a restriction as described above in applying this method. there were.
[0007]
Here, the double feed means that a plurality of sheets are sent out by a sheet feed roller at a time from a state where sheets are stacked on a sheet feeding table, with little or no deviation from each other, and they are sent out by a separation unit. This is a state in which the sheets cannot be completely separated, and depending on the sheets, many sheets may be shifted together.
[0008]
One possible cause of such a shift is that the coefficient of friction between the sheets of the sheet bundle stacked on the sheet feed table becomes extremely small depending on the location. Or at the boundary when paper is added to the paper feed tray. Also, in order to perform multi-color printing, etc., when the printed papers are aligned and stacked several times on the paper feed tray, or when different types of papers are mixed, the overlapping surface is easy to slip. It becomes a double feed.
As a countermeasure, it was known that the slippage could be prevented by searching for a slippery surface and removing the upper and lower sheets one by one from the boundary, but the operator was forced to perform the operation every time. Depending on the paper, it was impossible to remove all of the paper. In other words, it is not an exaggeration to say that this misalignment cannot be avoided when using a printing press.
[0009]
According to the present invention, even if a plurality of sheets causing the double feed described above enter the separation section, the separation of the sheets can be performed relatively easily and without any expensive cost. It is an object of the present invention to provide a feed separation device capable of performing the above-described operations.
[0010]
[Means for Solving the Problems]
The present invention, in order to achieve the above object,
(1) A friction member is pressed against a paper feed roller which rotates while being pressed against the stacked paper, and the paper is fed into a nip portion between the paper feed roller and the friction member. In a sheet separating apparatus that separates the stacked sheets one by one and feeds the stacked sheets one by one by using a difference in friction coefficient between the friction members, a holder that supports the friction member, and the holder is swung. A slider that freely supports, guide means for movably guiding the slider on a line connecting a center of the swing and a rotation center of the paper feed roller, and a guide member in which the friction member approaches the paper feed roller. A first urging means for applying a force between these members, and a second urging means for applying an urging force to the holder such that the holder oscillates around the center of the oscillation in a direction opposite to the sheet feeding direction. Biasing means and the second bias A stopper for preventing rotation of the holder due to a step; and a movable support member provided on a part of the holder so that the holder can move smoothly on the stopper. The surface is formed as a peripheral surface along an arc having a radius from the center of the swing to the distance from the center of the swing to the pressure contact surface between the friction member and the paper feed roller (claim 1).
[0011]
(2) A friction member is pressed against a paper feed roller which rotates while being pressed against the stacked paper, and the paper is fed into a nip portion between the paper feed roller and the friction member. In a sheet separating apparatus that separates the stacked sheets one by one and feeds the sheet in a sheet feeding direction by utilizing a difference in a friction coefficient between the friction members, a holder that supports the friction member, and the holder is swung. A slider that freely supports, guide means for movably guiding the slider on a line connecting a center of the swing and a rotation center of the paper feed roller, and a guide member in which the friction member approaches the paper feed roller. A first urging means for applying a force between these members, and a second urging means for applying an urging force to the holder such that the holder oscillates around the center of the oscillation in a direction opposite to the sheet feeding direction. Biasing means and the second bias A stopper for preventing rotation of the holder due to a step, and a movable support member provided on a part of the holder so that the holder can move smoothly on the stopper, and a surface of the friction member, The center of the swing is formed as a center, and a circumferential surface is formed along an arc having a radius from a center of the swing to a pressure contact surface between the friction member and the paper feed roller. A surface along an arc having a surface on the upstream side in the sheet feeding direction having a radius slightly larger than a distance from the center of the swing to the pressure contact surface between the friction member and the sheet feeding roller from the center of the swing. A step is formed at the boundary between the friction member and the holder by being formed with a surface (claim 2).
[0012]
[Action]
According to the first aspect, the holder rotates together with the friction member in the sheet feeding direction following the sheet when the sheet enters, and then rotates back in the direction opposite to the sheet feeding direction. By repeating the operation of pushing back the sheet in contact with the sheet to the upstream side in the sheet feeding direction, and leaving the remaining sheet as one, the separation function is achieved.
[0013]
According to the second aspect, the leading end of the sheet can easily pass through the step.
[0014]
【Example】
FIG. 1 schematically shows a sheet feeding / separating apparatus according to an embodiment of the present invention. In FIG. 1, a paper feed roller 1 is driven to rotate in a clockwise direction indicated by an arrow in FIG. 1 by a driving device (not shown). Below the paper feed roller 1, there is a holder 3 on which a friction member 2 is mounted. The holder 3 has a middle portion rotatably supported by a slider 4.
[0015]
The slider 4 has an H-shaped (not shown) side shape when viewed from the direction of the groove 5, and a rectangular (see FIG. 1) shape when viewed from above. The H-shaped groove portion is a guide plate. 9 is fitted in the opposite plate-like portion of a groove 5 formed in a bracket 10 provided on the back of the bracket 9, and is slidable along the groove 5. The groove 5 is formed linearly toward the center of the paper feed roller 1. Further, the slider 4 is elastically urged by the extensible separating pressure spring 6 mounted in the groove 5 toward the rotation center O of the paper feed roller 1.
[0016]
As a result, the friction member 2 is pressed against the paper feed roller 1 to form a paper separating unit including a press contact portion between the paper feed roller 1 and the friction member 2. The separation pressure spring 6 is an example of a first urging unit that applies a force between the friction member 2 and the paper feed roller 1 in a direction in which the friction member 2 approaches the paper supply roller 1.
[0017]
The intermediate portion of the holder 3 is pivotally connected to the holder 3 by a pivot 20. Thereby, the holder 3 can swing about the pivot 20. The groove 5 constitutes guide means for movably guiding the slider 4 along a line segment 21 connecting the center of the pivot 20 and the rotation center O of the paper feed roller 1.
[0018]
The pressing surface of the friction member 2 against the feed roller 1 is formed in an arc shape having a radius from the center 16 of the pivot 20 to the distance from the center to the pressing surface of the feed roller 1 of the friction member 2. Form a part of. The portion before the nip between the feed roller 1 and the friction member 2, that is, the portion that guides the leading end of the paper 12 to the nip between the feed roller 1 and the friction member 2, A thin plate 8 having a shape continuous with a part of the circumferential surface of the friction member 2 is mounted on the friction member 2. Alternatively, it is also possible to adopt a configuration in which the holder 3 itself forms an arc shape. As the thin plate 8, a material having a low coefficient of friction, for example, a stainless thin plate, a polyester film, a fluororesin tape, or the like can be used.
[0019]
The above-described step 22 is a step 22 that is higher in the outer peripheral surface portion on the upstream side in the sheet feeding direction of the holder 3 than in the outer peripheral surface portion of the friction member 2. Such a step 22 causes the surface of the holder 3 on the upstream side in the sheet feeding direction from the friction member 2 to be slightly smaller than the distance from the center 16 of the pivot 20 to the pressure contact surface between the friction member 2 and the sheet feeding roller 1. It is formed by forming a peripheral surface along an arc having a larger radius. The smaller the step 22, the thinner the step 22, ie, the smaller the step 22, the more smoothly the leading edge of the sheet can be fed into the sheet separating section, but empirically, about 0.05 mm to 0.15 mm. Are provided. FIG. 5 shows details of the step.
[0020]
On the lower end side 11 of the holder 3, the pressure contact surface of the friction member 2 against the paper feed roller 1 about the pivot 20 returns the paper 12 in a direction opposite to the paper supply direction indicated by the arrow 23 in a counterclockwise direction. That is, the extensible spring 7 as the second urging means is provided so as to generate a rotational force for rotating the holder 3 clockwise about the pivot 20. In addition, according to the thickness of the paper 12 to be fed, the holder 3 including the friction member 2 is slid along the groove 5 toward the center of the paper feed roller 1 so that the holder 3 can slide smoothly. A roller 13 is pivotally mounted. The roller 13 is normally stationary in a state of being abutted against a stopper 10 a constituted by a bent portion of the bracket 10 due to elasticity of the spring 7 in the extension direction, but the slider 4 moves along the groove 5. When it does, it moves by rotating on the stopper 10a together with the slider 4. Thus, the roller 13 constitutes a movable support member that movably supports the other end 11 of the holder 3. Further, a low friction member may be provided instead of the roller 13 so as to slide on the stopper 10a.
[0021]
Next, the operation of the sheet separating device will be described.
When the sheet feeding operation is started, the sheet feeding roller 1 is rotationally driven at a predetermined timing in a clockwise direction indicated by an arrow in FIG. 1 by a driving device (not shown). With this rotation, the direction in which the holder 3 previously hit against the stopper 10a as shown in FIG. 1 is rotated by the paper feed roller 1 as shown in FIG. It is rotated in the direction shown by a. To the nip formed by the paper feed roller 1 and the holder 3, the leading end 14 of the topmost paper of the papers 12 loaded on the paper feed table is conveyed. Then, the portion of the arc-shaped peripheral surface (or the thin plate 8) of the holder 3 upstream of the friction member 2 in the paper feeding direction (to the right in the drawing) has a small coefficient of friction with the paper. As shown by an arrow b in FIG. 3, the holder 3 swings in the direction slightly returning in the direction opposite to the sheet feeding direction.
[0022]
However, when the portion of the friction member 2 comes into contact with the back of the top end portion 14 of the paper, the paper feed roller 1 is again shown by the clockwise arrow a which is the paper feeding direction shown in FIG. The paper is rotated in the direction. Such swinging of the holder 3 and continuous movement of the sheet by the sheet feed roller are repeated several times until the trailing edge of the sheet passes through the sheet separating portion. By optimizing the relationship of the inertia, the number of repetitions can be minimized.
[0023]
Next, a case where a plurality of sheets of paper 12 enter the sheet separation unit will be considered. When the leading ends of the plurality of sheets enter the sheet separation section, as described above, the arc-shaped peripheral surface (or thin plate 8) of the holder 3 upstream of the friction member 2 in the sheet feeding direction (rightward in the drawing). Has the small friction coefficient, so that the holder 3 slightly returns in the direction opposite to the sheet feeding direction, but when the leading edge 15 of the second and subsequent sheets comes into contact with the friction member 2 as shown in FIG. Since the coefficient of friction between the sheets is smaller than the coefficient of friction between the friction member 2 and the sheet, for example, when three sheets enter the sheet separating section, as shown in FIG. When returning to the direction indicated by the arrow c opposite to the sheet feeding direction, the lowermost (third) sheet in contact with the friction member 2 is pushed back upstream (rightward in the drawing) in the sheet feeding direction. Next, assuming that the first and second sheets have simultaneously entered the sheet separation section, the holder 3 is once rotated in the sheet feeding direction by the conveying force of these sheets in the sheet feeding direction. Since the friction coefficient between the sheets is smaller than the friction coefficient between the friction member 2 and the second sheet, the two sheets immediately contacting the friction member 2 by the action of the spring 7 in the same manner as the third sheet. Push the sheet of paper in the paper feed direction upstream (to the right in the figure). Such an operation is repeated until one is left. Thus, only the top sheet is separated and sent out.
[0024]
Although the embodiment of the present invention has been described above, the present invention is not limited to this example, and various embodiments are possible.
[0025]
[Advantages of the embodiment]
According to the embodiment of the present invention, double feed prevention performance can be improved as compared with the conventional paper feed / separation mechanism, and the friction member 2 follows the paper when the paper 12 enters. , The stress exerted on the leading edge of the paper by the friction member 2 is greatly reduced, and as a result, wrinkles and scratches of thin paper, and paper breakage generated when the thick paper collides with the friction member 2 are prevented. It is possible to do.
[0026]
Further, the operator does not need to search for a slippery surface and remove the upper and lower surfaces one by one. Since the mechanism is simpler than that of the FRR system, it can be realized with high reliability and at low cost.
[0027]
In the embodiment according to the second aspect of the present invention, in which a step 22 is formed at the boundary between the friction member 2 and the holder 3, the basic advantages are the same as those of the first embodiment of the present invention. If a member smaller than the friction coefficient of the friction member 2, for example, a thin plate such as stainless steel, is provided in the guide portion of the holder, which guides the portion to the friction member 2, a predetermined step is easily formed, and the sheet feeding function is achieved. In addition, the durability can be greatly improved.
[0028]
【The invention's effect】
According to the first aspect of the present invention, even if a plurality of sheets that cause double feeding enter the separation section, the separation of the sheets can be performed relatively easily and without any expensive cost. Can be provided.
[0029]
According to the second aspect of the present invention, it is possible to further fulfill the sheet feeding function and to greatly improve the durability.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view illustrating an overall configuration of a sheet feeding / separating apparatus suitable for carrying out the present invention.
FIG. 2 is a partial cross-sectional view of a sheet separating unit illustrating a sheet separating process.
FIG. 3 is a partial cross-sectional view of a sheet separating unit illustrating a sheet separating process.
FIG. 4 is a partial cross-sectional view of a sheet separating unit illustrating a sheet separating process.
FIG. 5 is a diagram illustrating a step portion of the holder.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 paper feed roller 2 friction member 3 holder 6 separation pressure spring 7 (as first urging means) spring 10a (as second urging means) stopper 22 step

Claims (2)

A friction member is pressed against a paper feed roller that rotates while being pressed against the stacked paper, and the paper is fed into a nip between the paper feed roller and the friction member. A sheet separating device that separates the stacked sheets one by one and feeds the stacked sheets one by one using a difference in friction coefficient between the stacked sheets.
A holder for supporting the friction member,
A slider that swingably supports the holder,
Guide means for movably guiding the slider on a line connecting the center of the swing and the rotation center of the paper feed roller;
First biasing means for causing a force in a direction in which the friction member approaches the paper feed roller to act between the members;
Second urging means for applying an urging force to the holder such that the holder swings in a direction opposite to a sheet feeding direction about the center of the swing,
A stopper for preventing rotation of the holder by the second urging means;
A movable support member provided on a part of the holder so that the holder can move smoothly on the stopper,
Has,
The surfaces of the friction member and the support portion are formed by a circumferential surface along an arc having a radius from a center of the swing to a pressure contact surface between the friction member and the paper feed roller from the center of the swing. A sheet separation device, characterized in that: A friction member is pressed against a paper feed roller that rotates while being pressed against the stacked paper, and the paper is fed into a nip between the paper feed roller and the friction member. A sheet separating device that separates the stacked sheets one by one and feeds the stacked sheets one by one using a difference in friction coefficient between the stacked sheets.
A holder for supporting the friction member,
A slider that swingably supports the holder,
Guide means for movably guiding the slider on a line connecting the center of the swing and the rotation center of the paper feed roller,
First biasing means for causing a force in a direction in which the friction member approaches the paper feed roller to act between the members;
A second urging unit that applies an urging force to the holder such that the holder swings in a direction opposite to a sheet feeding direction around the center of the swing,
A stopper for preventing rotation of the holder by the second urging means;
A movable support member provided on a part of the holder so that the holder can move smoothly on the stopper,
Has,
The surface of the friction member is formed with a peripheral surface along an arc having a radius from a center of the swing to a pressure contact surface between the friction member and the paper feed roller from the center of the swing,
The surface of the holder on the upstream side of the friction member in the sheet feeding direction is set to be less than the distance from the center of the swing to the pressure contact surface between the friction member and the sheet supply roller with the center of the swing being the center. A sheet separating device characterized in that a step is formed at a boundary between the friction member and the holder by forming the peripheral surface along an arc having a larger radius.

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