JP2763843B2 - Sheet feeding device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding apparatus for feeding sheets such as recording paper one by one in copying machines and printers.

[0002]

2. Description of the Related Art A typical prior art feeding apparatus 1 is shown in FIG.
Shown in The recording paper P in the copying machine is stacked on the mounting plate 2, and the lowermost recording paper P1 of the recording papers P is vacuum-adsorbed by the feeding stretch belt 3 to form a pair of transport rollers. 5 and is further nipped and transported by the transport rollers 5. The feeding stretch belt 3 has a large number of air passage holes 4. When the vacuum suction box 6 disposed in the feeding tension belt generates a negative pressure, the lowermost recording paper P1 of the stacked recording papers P is vacuum-sucked through the air passage holes 4. At the time of this vacuum suction, the lowermost recording paper P1 and the second or more remaining recording papers stacked thereon are separated by an air flow (arrow 8) ejected from the air ejection device 7. (Showing the flow), the downstream end in the transport direction A is discarded, and simultaneous vacuum suction of a plurality of recording sheets is prevented.

At this time, as shown in the figure, the air flow from the air jetting means 7 moves toward the center of the recording paper P while separating the downstream end in the transport direction of the recording paper P, and simultaneously moves vertically. The recording paper P expands and largely separates above the feeding tension belt 3. Therefore, while the lowermost recording sheet P1 is not yet sufficiently vacuum-sucked to the feeding stretching belt 3, this air flow is generated between the feeding stretching belt 3 and the lowermost recording sheet P1. When entering, the entered air expands to form an air pocket D, and the lowermost recording sheet P1 is largely separated upward from the feeding stretch belt 3, so that there is a problem that vacuum suction becomes difficult.

Therefore, conventionally, a feeding apparatus 1 shown in FIG.
A configuration is adopted in which the recording paper P is prevented from being excessively separated from the feeding tension belt 3 by using a pressing member 9 generally called a mylar or the like as shown in FIG. In FIG.
Parts common to those in FIG. 5 are denoted by the same reference numerals.

[0005] The pressing member 9 is an elongated plate-like member formed of a flexible material such as polyethylene terephthalate (PET) in the form of a thin film. One end 9a in the longitudinal direction of the holding member 9 is fixed to a rear end regulating member 9b of the recording paper provided in the intermediate tray with an adhesive or the like, and the other end 9b is located at the uppermost part of the stacked recording papers P. The recording paper Pn comes into contact with a portion of the recording paper Pn located above the feeding stretch belt 3 and is pressed downward. With this holding member 9,
The air flow from the air ejecting device 7 is prevented from separating the lowermost recording sheet P1 and the feeding stretching belt 3, thereby facilitating vacuum suction.

[0006]

In a copying machine using such a holding member 9, when a conveyance failure such as a paper jam occurs near the feeding device 1a, the paper jammed by the user. It is necessary to perform operations such as removal of the waste. When the user performs the removing operation, the pressing member 9 is located in a place where the user can easily touch it, so that the pressing member 9 may be damaged or deformed. In particular, the holding member 9 has a thin and elongated shape, and is often deformed and easily curved upward due to its material. In this case, it is not possible to prevent a state in which the stacked recording paper P near the feeding tension belt 3 is separated from the feeding tension belt 3. There is a problem that the material is not properly conveyed by suction.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent the suction conveyance means from being excessively separated from the lowermost sheet member, and also prevent the function for preventing the loss from being lost due to a user's operation or the like. Accordingly, an object of the present invention is to provide a sheet feeding device capable of surely performing suction conveyance of a sheet.

[0008]

According to the present invention, there is provided (a) a suction conveying means, wherein a feeding stretch belt having a large number of air passage holes is provided at intervals in front and rear of the feeding direction. A vacuum suction box, which is open upward and has a negative pressure in the internal space, is disposed directly below the upper tension portion of the feeding tension belt wound around the pair of rollers, and the upper tension portion is The plurality of stacked sheets are driven so as to travel in the feeding direction, and the downstream end in the feeding direction of the plurality of stacked sheets is attached to the suction conveyance unit mounted on the upper stretched portion. Downstream from the sheet body in the feeding direction,
And a first air ejecting unit that is disposed above the stacked sheet bodies and injects air toward an end of the stacked sheet bodies on the downstream side in the feeding direction to blow the ends, c) a second air ejecting means disposed just above the feeding tension belt and injecting air just below the uppermost portion of the stacked sheet bodies. Feeding device.

[0009]

According to the present invention, the stacked sheets are:
The sheet is conveyed one by one from the lowermost part by the suction conveyance means. At the time of the suction, the first air jetting means jets the airflow toward the downstream end of the sheet in the conveying direction, and the airflow blows the vicinity of the end of the sheet, so that the suctioning means conveys the sheet one by one. In such a state that it is easy to adsorb.

[0010] The second air ejecting means ejects air from above the stacked sheet bodies toward the uppermost sheet body and presses the air between the sheets stacked from the first air ejecting section. Prevents air that has entered from expanding excessively up and down. That is, since the air that has entered between the lowermost sheet member and the suction conveyance device is prevented from being excessively expanded, the lowermost sheet member is not excessively separated from the suction conveyance device. Therefore, the lowermost sheet body is provided for suction conveyance in a state suitable for suction at a distance from the suction conveyance unit. In particular, according to the present invention, the second air injection means is disposed directly above the upper stretched portion of the feeding stretch belt wound around the pair of rollers 41, 42 of the suction and transport means. From the ejection means, air is ejected directly downward toward the uppermost part of the stacked sheet bodies, and thus the sheet bodies are first pressed by the second air ejection means against the upper stretched portion of the suction conveyance means. . As a result, the lowermost sheet body of the stacked sheet bodies is sucked to the upper tension portion by negative pressure. In a state where the lowermost sheet body is securely sucked to the upper stretch portion of the feeding stretch belt of the suction transport means,
Air is ejected from the first air ejecting means disposed above the sheet body at the downstream end of the stacked sheet bodies in the feeding direction by the air ejecting means, and the air is ejected from the first sheet ejecting means. The downstream end in the feeding direction is blown. As a result, the lowermost sheet member on the upper tension portion of the feeding tension belt and the sheet member above it are moved to the first position.
Separated by air from the air injection means. In a state where the lowermost sheet body of the stacked sheet bodies is securely sucked by the feeding stretch belt, the upper stretch portion of the transporting stretch belt and the lowermost sheet body are mutually reciprocated. In a state where the position is accurately maintained, only the lowermost sheet body is conveyed by the traveling of the upper stretch portion of the feeding stretch belt. The lowermost sheet body of the stacked sheet bodies can be accurately conveyed.

[0011]

FIG. 1 is a simplified sectional view of an embodiment of the present invention. The feeding device 10 is a copier 1 shown in FIG.
It is used as one so-called intermediate tray. The recording paper to be copied is supplied one by one from the recording paper supply means 13, and is guided to a transfer area 16 of a photoreceptor 15 having a straight cylindrical shape via a transport path 14. The circulating document supply means 17 guides the document to a reading area 18, and this document image is formed on the exposure area 20 of the photoconductor 15 by the optical means 19, and thus the image is formed on the photoconductor 15 charged by the corona discharger 21. An electrostatic latent image of the document is formed. This electrostatic latent image is developed by developing means 2
The toner image is visualized by the toner image 2, transferred to one surface of the recording paper passing through the transfer area 16, and then fixed by the fixing unit 23.

In order to make a copy on the other surface of the recording paper, the recording paper having one surface fixed by the fixing means 23 is an intermediate tray via a transport path 24 and further via a switchback path 25. The sheet is temporarily stacked on the feeding device 10. The recording paper from the feeding device 10 passes through the transport path 26 and the transport path 14 and returns to the transfer area 16.
And another original is copied on the other surface of the recording paper.
The recording paper subjected to the double-side copying in this manner is fixed by the fixing unit 23, discharged from the discharge roller 28 to the tray 29, and received.

Recording papers P are stacked and mounted on a mounting plate 31 of the feeding device 10. A notch 60 is formed at the downstream end of the placement plate 31 in the feeding direction A, and the feeding means 32 faces the notch 60. The feeding means 32 includes a feeding stretch belt 38 and a pair of rollers 4.
1 and 42 and a vacuum suction box 43. A plurality of the feeding stretch belts 38 are arranged adjacent to each other in the width direction, and a plurality of air passage holes 40 are formed in the feed stretch belt 38. The feeding tension belt 38 is moved in the feeding direction A.
It is wound around rollers 41 and 42 provided at intervals in the front and rear directions. These rollers 41 and 42 are driven by a motor (not shown) to drive the feeding tension belt 38 to travel.

The upper stretch portion 38a of the feeding stretch belt 38
A vacuum suction box 43 that is open upward is disposed immediately below the box. The vacuum suction box 43 is sucked by a fan 44 described later, and the internal space thereof is set to a negative pressure. At this time,
An air passage hole 40 formed in the feeding tension belt 38
Through which the recording paper P is vacuum-sucked. In this way, the feeding unit 32 feeds the vacuum-adsorbed lowermost recording sheet P1 of the recording sheets P stacked on the mounting plate 31 in the feeding direction A. The feeding direction A of the feeding means 32
A feeding unit 34 for further feeding the recording paper fed from the feeding unit 32 is disposed downstream in the direction. The feeding means 34 includes a pair of rollers 35 and 36 which are arranged vertically and sandwich and feed the recording paper. An air ejecting device 45 is provided so as to face upward on the downstream side in the transport direction A of the stacked recording papers P. The air ejecting device 45 includes a nozzle 46, and ejects an air flow from the nozzle 46 toward a downstream end in the feeding direction A of the recording paper P, and blows this end.

Feeding direction A of stacked recording papers P
The air injection device 50 faces the vicinity of the downstream end in the direction and directly above the portion located on the feeding tension belt 38.
The air ejecting device 50 injects air directly downward onto the uppermost recording paper Pn of the recording paper P.

FIG. 3 is a system diagram showing the relation of each part in the feeding device 10 of the present embodiment. The vacuum suction box 43 is connected to a fan 44 via a damper 51, and the air is sucked by the fan 44 to a negative pressure. Air injection device 45
The air injection device 50 is connected to the same fan 47 via dampers 52 and 53, respectively, and injects air sent from the fan 47. The operations of the fans 44 and 47 and the dampers 51 to 53 are integrally controlled by a central processing unit (CPU) 54.

FIG. 4 is a timing chart showing an example of the timing of each part in the feeding operation of the feeding device 10 of the present embodiment. At time t0, the copy operation is started by operating the copy start key, and at the same time, the air injection device 5 is operated.
0 and the air injection device 45 start air injection. After the copying operation is started, after a period of time, for example, three seconds, during which the recording papers P are stacked and mounted on the mounting plate 31, the vacuum suction box 43 is set to a negative pressure to start suction. The feeding tension belt 38 is driven with a delay of, for example, 0.3 seconds from the start of the suction. This 0.3 second is a time for sufficiently separating the stacked recording papers P by the air ejecting devices 45 and 50 and setting the recording papers P in a state suitable for suction.

The conveying rollers 35, 36 are driven, for example, 0.15 seconds after the start of the driving of the feeding tension belt 38. This 0.15 seconds is equivalent to the feeding tension belt 38.
The lowermost recording sheet P1 conveyed by the conveying roller 3
It is the time to be transported to around 5,36. When the recording paper P1 conveyed by the feeding stretching belt 38 is caught by the conveying rollers 35 and 36 and starts to be conveyed, the vacuum suction box 43 and the feeding stretching belt 38 are turned off. The operations of these components continue until all the recording paper P on the mounting plate 31 is conveyed.

The air injection devices 45 and 50 operate at time t0.
To the time t1 until the copying operation is completed.

As a prior art, as shown in FIG. 5, if the recording paper P is to be fed without blowing air from the air jetting means 50, the downstream end of the recording paper P in the feeding direction A is blown. For this reason, the airflow that has entered between the recording papers P further expands toward the center of the recording papers P to form an air pocket D. Therefore, the airflow between the lowermost recording paper P1 and the feeding tension belt 3 is increased. In some cases, an excessive air pocket D may be formed, and the recording paper P1 is separated from the feeding tension belt 3. On the other hand, in the configuration of the present embodiment, even if the air reservoir D that has entered between the lowermost recording paper P1 and the feeding tension belt 38 attempts to inflate excessively, the airflow injection device 50 is positioned directly above. The air flow injected by the air reservoir D
To prevent the recording paper P1 from being excessively separated from the feeding tension belt 38. Therefore, since the two air ejecting devices 45 and 50 always eject simultaneously, an appropriate air flow is formed that can prevent the recording paper P from being excessively separated from the feeding stretch belt 38, and the lowermost portion is formed. The recording paper P1 is reliably attracted and conveyed by the feeding tension belt 38.

The air jetting device 50 is arranged at a fixed distance from the recording paper P1 and is not a member that is easily broken or deformed like the pressing member 9 described above as a conventional technique. When the user performs an operation to remove an obstacle such as a paper jam near the feeding device 10, there is no fear that the air flow injection device 50 may be accidentally touched and damaged or deformed. Therefore, as described above, the reliability of the reliable feeding of the recording paper can be remarkably improved.

[0022]

[0023]

As described above, according to the present invention, the air flow by the first air injection means is jetted to the stacked sheet members at the downstream end in the conveying direction, and the second air jet is jetted from above. An air flow is injected by the means.

With this arrangement, the end portion is separated by the air flow from the first air injection means, and a part of the air flow is expanded between the suction conveyance means and the lowermost sheet member to thereby reduce the air flow. It is possible to prevent the sheet body from being largely separated from the suction conveyance means.

[0025] Therefore, an appropriate distance can be maintained between the suction conveyance means and the lowermost sheet member, so that the suction conveyance operation can be surely performed one by one.

Further, since the second air injection means is separated from the sheet member and the suction conveyance means, and is relatively unlikely to be deformed or damaged, the second air injection means according to the present invention can be used to remove the conveyance obstacle by the user. I accidentally touched the vicinity of the feeder,
Deformation and breakage are prevented.

Therefore, it is possible to improve the reliability of the suction conveyance in the sheet feeding device. In particular, according to the present invention, the stacked sheet members are pressed against the upper stretched portion of the feeding stretch belt of the suction / conveying means by the air jetted directly downward from the second air jetting means. Thereby, the lowermost sheet body of the stacked sheet bodies is securely adsorbed to the upper stretch portion, and in this state, the air from the first air ejecting means is supplied in the feeding direction of the stacked sheet bodies. Injection is performed toward the downstream end, the end is discarded, and the lowermost sheet and the upper sheet are separated by the air from the first air injection means. Therefore, the lowermost sheet body can be conveyed in the feeding direction while maintaining the accurate position relatively to the upper stretch portion of the feeding stretch belt. Further, according to the present invention, the first air ejecting unit is disposed downstream of the stacked sheet members in the feeding direction, and injects air toward a downstream end of the sheet member in the feeding direction, The second air injection means is disposed right above the upper stretch portion of the feeding stretch belt and injects air directly downward, so that the air from the first air injection means and the air from the second air injection means are injected. The air does not collide with each other, and each of the jetted air flows can be effectively used.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a feeding device 10 according to an embodiment of the present invention.

FIG. 2 shows a copying machine 1 provided with a feeding device 10 of the present embodiment.
1 is a side sectional view of FIG.

FIG. 3 is a system diagram showing a relation between each part of the feeding device 10 according to the embodiment.

FIG. 4 is a timing chart showing an example of the timing of each unit in the feeding operation of the feeding device 10 of the present embodiment.

FIG. 5 is a side sectional view showing a typical prior art example.

FIG. 6 is a side sectional view showing a typical prior art example.

[Explanation of symbols]

 Reference Signs List 10 feeding device 31 mounting plate 32 feeding means 38 feeding stretching belt 43 vacuum suction box 45, 50 air injection device

Claims (1)

(57) [Claims] (A) A suction conveying means, wherein a feeding stretch belt having a large number of air passage holes is wound around a pair of rollers provided at intervals in front and rear of the feeding direction. A vacuum suction box, which is open upward and has a negative internal space, is disposed immediately below the upper tension portion of the feeding tension belt so that the upper tension portion travels in the feeding direction. Ends of the driven and stacked plurality of sheet bodies on the downstream side in the feeding direction are suction-conveying means mounted on the upper stretch portion, and (b) downstream of the stacked sheet bodies in the feeding direction. To
And a first air ejecting unit that is disposed above the stacked sheet bodies and blows air toward an end of the stacked sheet bodies on the downstream side in the feeding direction to blow the ends, c) a second air ejecting means disposed just above the feeding tension belt and injecting air just below the uppermost portion of the stacked sheet bodies. Feeding device.