JP4003073B2 - Paper feeder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a paper feeding device for an electrophotographic apparatus, and more particularly to a paper feeding device using an air flow.
[0002]
[Prior art]
FIG. 1 shows the structure of a paper feeding device using an air flow, that is, a conventional paper feeding device of an electrophotographic apparatus generally called an air suction system or an air separation system. In FIG. 1, a sheet 2 stacked on a sheet lifting table 1 is always kept at a constant height by a sheet upper surface detection sensor 3 and a control unit 4 that controls the driving of the sheet lifting table 1 based on information from the sheet upper surface detection sensor 3. It is controlled to be located in Above the sheet 2, a vacuum charging chamber 5, a belt member having a suction hole generally called a suction belt 6, and a driving device 7 for driving the suction belt 6 are installed.
[0003]
An air ejector 8 for separating and floating the upper layer portion of the stacked paper by blowing an air flow is provided on the front surface in the paper transport direction. The air ejector 8 causes the air 2 to float. The suction belt 6 is sucked and transported to feed paper.
[0004]
Downstream of the paper conveyance direction, a so-called conveyance roller 9 which is a paper conveyance unit that receives the paper 2 to be sucked and conveyed and conveys it to an image forming unit (not shown) is provided.
[0005]
In the sheet feeding apparatus configured as described above, various devices have been conventionally made in order to obtain a sufficient sheet separation and floating effect by the above-described air blowing. For example, as shown in FIG. 2, the configuration of the air ejector 8 described above is configured such that air is blown horizontally or obliquely upward with respect to the sheet 2 to separate and float the upper layer sheet, and the adsorption Auxiliary jet outlet that blows air obliquely upward toward the belt 6 and separates the uppermost sheet and the lower sheet, that is, the first sheet and the second sheet, by the air flow reflected from the suction belt 6 11 is a method of ensuring a reliable separation and levitation effect by providing a plurality of independent outlets according to the role (see, for example, Patent Document 1).
[0006]
In addition to the paper separation and floating mechanism shown in the above example, there is an example in which the shape of the air outlet is devised in order to further improve the performance. In this example, the shape of the jet outlet corresponding to the main jet outlet for performing separation and levitation is a trapezoidal shape, and the spraying pressure is reduced from the bottom to the top of the stacked paper to improve the separation performance. This is devised so that multiple bundles reach the suction belt and do not cause double feeding (see, for example, Patent Document 2).
[0007]
Furthermore, as another example of devising the shape of the air outlet, the above-mentioned shape of the air outlet is an “H” shape, or a combination of other geometric shapes, and the paper is separated and floated by the air flow. Is arbitrarily changed in the vertical direction of the paper (for example, see Patent Document 3). This example can be said to be an advanced type of the above-mentioned Patent Document 2.
[0008]
Coated paper with high glossiness and high paper smoothness, thin paper such as tracing paper, and paper such as OHP with the recent color printing and diversification of printed matter in the electrophotographic industry As a method to further improve separation and flying performance in order to cope with printing on paper, there is a method of configuring and controlling the diameter, angle, and strength of the air flow according to the type of paper so that it can be changed. (For example, refer to Patent Document 4). Further, there is a method in which an air outlet is provided on the side surface of the paper so that the strength of the air flow can be adjusted, and the strength is controlled according to the type of the paper (for example, see Patent Document 5).
[Patent Document 1]
Patent No. 2934442 [Patent Document 2]
JP 63-8137 A [Patent Document 3]
Japanese Patent Laid-Open No. 2002-2986 [Patent Document 4]
JP-A-10-67442 [Patent Document 5]
Japanese Patent Laid-Open No. 11-349165
[Problems to be solved by the invention]
As described above, along with the recent diversification of printed matter, paper feeders using airflow are increasingly required to have high performance. Depending on the type of paper, the above-mentioned air outlet There are cases where sufficient separation and levitation performance cannot be obtained simply by devising the shape of the above. Further, in the method of controlling the diameter and angle of the jet nozzle and the strength of the air flow according to the type of paper, the apparatus and control become complicated, and the manufacturing cost tends to increase.
[0010]
SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a paper feeding device that can obtain effective paper separation and flying performance with a simple configuration, thereby reducing the manufacturing cost. The purpose is to provide.
[0011]
[Means for Solving the Problems]
The object is to be disposed at both ends of the storage member that can store a plurality of sheets, and located in front of the sheet stored in the storage member in the transport direction, with the central portion of the sheet interposed therebetween. A pair of one or more first outlets for ejecting air, and a second outlet for ejecting air, which is located at a substantially central portion of the paper, and is ejected from the first and second outlets. In the paper feeding device having a conveying means for adsorbing and conveying the paper separated and floated by the air, the air flow from the first ejection port is caused to flow from the lower part of the central part of the paper. It is achieved by ejecting at both ends and upward.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. 3 and 4 show an embodiment according to the present invention. 3 and 4, 2 is a sheet, 6 is an adsorption belt, 12 is a first ejection port 13 that ejects air toward the upper layer of the sheet, and a second ejection port that ejects air toward the adsorption belt 6. 14 and a vacuum charging chamber composed of an auxiliary jet port 15 that jets air toward the upper layer of the sheet 2 in the same manner as the first jet port 13. In general, the ejection port is referred to as a nozzle and the vacuum charging chamber is referred to as a chamber. Hereinafter, the ejection port is referred to as a nozzle, and the vacuum charging chamber is referred to as a chamber. An air flow is supplied to the chamber 12 from a blower (not shown) through a duct 16. Reference numeral 17 denotes a jet outlet for jetting air from the side surface with respect to the conveyance direction of the paper 2. Similarly to the chamber 12, an air flow is supplied from a blower (not shown), and between the blower and the jet outlet 17. The switching valve 18 is installed, and the air flow can be opened and closed. The jet port 17 provided on the side surface of the sheet is hereinafter referred to as a side nozzle. Further, the suction belt 6 is configured to rotate in contact with the opening of the suction chamber 20 through the suction duct 19, and is configured to suck the paper 2 through a hole formed in the surface of the suction belt 6.
[0013]
The operation of feeding the sheet 2 in the sheet feeding device configured as described above will be described. First, the upper layer sheets of the sheet 2 are mutually connected by the air flow ejected from the first nozzle 13 of the chamber 12. Ascends while separating. In this state, when the hole of the suction belt 6 is located at the opening of the suction chamber 20 and the suction starts, the uppermost sheet, that is, the first sheet starts to rise, and the uppermost sheet and so on rise accordingly. Start. Next, in the process in which the first sheet approaches the suction belt 6, the air flow from the second nozzle 14 is reflected on the suction belt 6, and then enters between the first sheet and the second sheet. The first sheet and the second sheet are completely separated. Thereafter, the first sheet that has arrived at the suction belt 6 is conveyed by the rotation of the suction belt 6. At this time, since the leading edge of the second and subsequent sheets is pressed downward by the air from the second nozzle 14, a phenomenon called so-called take-out does not occur. One of the important points in this series of sheet feeding operations is separation and floating of the sheet 2 by the first nozzle 13. If an appropriate gap is not formed between the individual sheets that float, the first sheet In the process of adsorbing the sheet to the adsorption belt 6, the air from the second nozzle 14 does not sufficiently flow in, and the sheet 2 rises as a bundle with the first sheet and the second sheet, and possibly the subsequent sheets. In addition, a phenomenon of being conveyed together, so-called double feeding, occurs. Further, when the first sheet is conveyed, if the braking force for the second and subsequent sheets 2 by the second nozzle 14 is not sufficient, take-out occurs.
[0014]
In the present invention, focusing on the separation and floating action of the paper 2 by the first nozzle 13, the separation performance is improved by devising the arrangement of the nozzles. In the present invention, as shown in FIG. 4, the first nozzle 13 blows air to the front surface of the sheet 2 from below the substantially central portion of the sheet 2 to above both ends of the sheet. The nozzle 13 was tilted and arranged so as to spread upward. As a result, as shown in FIG. 5, the shape of the sheet 2 in the range where the airflow strikes is vertical because the lower part is curved in a shape in which the central part is convex upward and the upper part is curved in the direction in which the central part is recessed. Compared with the case of FIG. 6 in which the first nozzles 13 are arranged in the direction, both end portions of the sheet 2 are floated in a state in which the distance between the sheets is large.
[0015]
In addition, as shown in FIG. 5, since the close contact between the sheets increases at the center of the sheet 2, the friction load between the sheets increases, and therefore the occurrence rate of take-out decreases. In the present embodiment, as shown in FIG. 4, the third nozzle 21 is installed on both sides of the first nozzle 13 and at an upper position, and into the gaps at both ends of the paper formed by the first nozzle 13. The effect of preventing double feeding is improved by effectively flowing air and further improving the separation between the first and second sheets. However, the amount of air ejected by the third nozzle 21 needs to be smaller than the amount of air ejected by the first nozzle 13. For example, the amount of air ejected by the third nozzle 21 is the amount of air ejected by the first nozzle 13. In the case of exceeding 1, the floating of the paper 2 by the first nozzle 13 is hindered, and there is a possibility that a suction error will occur.
[0016]
Further, in this embodiment, as shown in FIGS. 3 and 4, it is possible to install a nozzle 17 for ejecting an air flow from the side surface direction of the paper 2 to improve the separation and floating functions. This is because air can be effectively fed into the gaps at both ends of the paper formed by the first nozzle 13. This method of jetting airflow from this side is used for printing heavy paper that is heavy and difficult to separate and float, or when printing curled paper that tends to be insufficiently lifted when air is blown from the front of the paper. It is an effective means. However, when air is blown from this side, due to the property that the force is applied from the lateral direction to the paper transport direction, in the case of thin paper such as tracing paper, the paper "flutters" and the posture is disturbed. Therefore, as shown in the present embodiment, it is possible to obtain a stable paper feeding performance by providing the switching valve 18 and performing switching control depending on the type of paper. Further, when printing a sheet that is long in the width direction, as shown in FIG. 4, an auxiliary nozzle 15 for assisting in insufficient floating of the end of the sheet may be installed outside the first nozzle 13. It is effective to improve the effect.
[0017]
In the configuration described above, the size of each nozzle varies depending on the distance from each nozzle to the front surface of the paper, the airflow blowing angle, the airflow speed, the airflow, and the relative position of each nozzle, and printing. Since the numerical value to be set differs depending on the type of paper to be used, it is difficult to indicate a constant value. However, in this embodiment, the first nozzle 13, the second nozzle 14, For the three nozzles 21, the first nozzle 13 is a long hole having a width of 3 mm, a length of 17 mm, and an inclination angle of 45 °, the second nozzle 14 is a circular hole having a diameter of 5 mm, and the third nozzle 21 is a circular hole having a diameter of 4 mm. did. At this time, when the air flow bands ejected from the first nozzle 13 and the third nozzle 21 are set so as to collide with a range of about 4 mm downward from the upper layer portion of the stacked sheets 2, effective separation and flying performance is achieved. Obtained.
[0018]
【The invention's effect】
According to the present invention, an effective sheet separation and floating effect can be obtained with a simple configuration. For this reason, there are cases where it is necessary to use a method of controlling the size, angle, air flow strength, etc. of the air ejection nozzle according to the type of paper, which is performed for the purpose of sufficient separation and lifting performance of the paper. This reduces the cost of the device itself.
[Brief description of the drawings]
FIG. 1 is a diagram showing a structure of a paper feeding device using an air flow in the prior art.
FIG. 2 is a cross-sectional view showing a structure of a paper feeding device using an air flow in the prior art.
FIG. 3 is a cross-sectional view illustrating a state where a sheet is separated and floated by an air flow ejected from each air ejection nozzle according to an embodiment of the present invention.
FIG. 4 is a front view showing the arrangement of air ejection nozzles according to an embodiment of the present invention.
FIG. 5 is a front view illustrating an embodiment of the present invention, in which a sheet upper layer is separated and floated by an air ejection nozzle.
FIG. 6 is a front view showing a state in which a paper upper layer portion is separated and floated by an air ejection nozzle in the prior art.
[Explanation of symbols]
1 is a paper lifting table, 2 is paper, 3 is a paper upper surface detection sensor, 4 is a control means, 5 is a vacuum charging chamber, 6 is a suction belt, 7 is a driving device, 8 is an air ejector, 9 is a transport roller, 10 is a main jet, 11 is an auxiliary jet, 12 is a vacuum charging chamber (chamber), 13 is a first jet (first nozzle), 14 is a second jet (second nozzle), and 15 is an auxiliary jet. An outlet, 16 is a duct, 17 is a side nozzle, 18 is a switching valve, 19 is a duct, 20 is a suction chamber, and 21 is a third jet outlet (third nozzle).

Claims (4)

A storage member capable of storing a plurality of sheets of paper, and an air jet which is located on the front side in the transport direction of the paper stored in the storage member and is disposed on both sides with the approximate center portion of the paper interposed therebetween A pair of or more first jet outlets and a second jet outlet that is located at a substantially central portion of the paper and ejects air, and is separated by air ejected from the first jet outlet and the second jet outlet. In the sheet feeding device provided with a conveying means for sucking and conveying the floated paper, the air flow from the first jet port is passed from substantially below the central portion of the paper to both ends of the paper. And a paper feeding device which ejects upward. A storage member capable of storing a plurality of sheets of paper, and an air jet which is located on the front side in the transport direction of the paper stored in the storage member and is disposed on both sides with the approximate center portion of the paper interposed therebetween A pair of or more first jet outlets and a second jet outlet that is located at a substantially central portion of the paper and ejects air, and is separated by air ejected from the first jet outlet and the second jet outlet. In the sheet feeding device provided with a conveying means for sucking and conveying the floated paper, the air flow from the first jet port is passed from substantially below the central portion of the paper to both ends of the paper. In addition, a third jet outlet is provided in the vicinity of the first jet outlet for jetting an air amount smaller than the amount of air jetted from the first jet outlet, and the third jet outlet is disposed. The height is equal to or higher than the first outlet. Sheet feeder to. A storage member capable of storing a plurality of sheets of paper, and an air jet which is located on the front side in the transport direction of the paper stored in the storage member and is disposed on both sides with the approximate center portion of the paper interposed therebetween A pair of or more first jet outlets and a second jet outlet that is located at a substantially central portion of the paper and ejects air, and is separated by air ejected from the first jet outlet and the second jet outlet. In the sheet feeding device provided with a conveying means for sucking and conveying the floated paper, the air flow from the first jet port is passed from substantially below the central portion of the paper to both ends of the paper. In addition, the paper feeding device is characterized in that a jetting outlet is provided which is ejected upward and is located in a side surface direction with respect to the conveyance direction of the paper and ejects air on the side surface of the paper. A storage member capable of storing a plurality of sheets of paper, and an air jet which is located on the front side in the transport direction of the paper stored in the storage member and is disposed on both sides with the approximate center portion of the paper interposed therebetween A pair of or more first jet outlets and a second jet outlet that is located at a substantially central portion of the paper and ejects air, and is separated by air ejected from the first jet outlet and the second jet outlet. In the sheet feeding device provided with a conveying means for sucking and conveying the floated paper, the air flow from the first jet port is passed from substantially below the central portion of the paper to both ends of the paper. In addition, the air is ejected upward, and an air amount smaller than the amount of air ejected from the first ejection port is ejected in the vicinity of the first ejection port, and the arrangement height of the ejection port is the first ejection port. A third jet outlet that is equivalent to or above the Paper feeding device located laterally to the direction, characterized in that a spout for spouting air to the side of the paper.

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