JPH10316264A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the durability and the paper feeding performance, by jetting the air to an edge part of the sheets loaded on a sheet loading part, for floating the sheets of an upper part, and sucking and conveying the uppermost sheet by a convey belt, to be conveyed and fed. SOLUTION: The air jetted from a separation nozzle 108 is entered among the sheets S accommodated in a paper feeding tray 101a, thereby an upper part of the sheets are floated while separated from each other. A suction valve is opened by a control unit. Whereby the negative pressure is generated in a suction duct 11a, for sucking the uppermost sheet S1 among the sheets S floated by the air from the separation nozzle 108, onto a surface of a convey belt 106a. On this occasion, the sheet S2 positioned lower than the sheet S1 is sometimes sucked too, but the sheet S2 is returned by the flowing of the air jetted from the separation nozzle 109, between the sheet S1 and the sheet S2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a side tray paper feeder which is optionally mounted on an image forming apparatus such as an electrophotographic copying machine.

[0002]

2. Description of the Related Art Some image forming apparatuses such as copiers are provided with a side tray paper feeder as an option separately from a standard paper feeder.

An example of such an optional paper feeder will be described with reference to FIG.

This paper feeder is a roller paper feeder that conveys the sheets stacked on a paper feed tray to a downstream side by rotating a paper feed roller whose surface is formed of an elastic body such as rubber. .

[0005] This roller paper feeder has three paper feed trays 101a, 101b and 101c. Here, the paper feed tray 101 (101a, 101b, 101
Paper is to be fed from the paper feed tray 101a in c).

At the time of paper feeding, first, the pickup roller 31
“a” sends out the uppermost sheet among the sheets S stored in the sheet feeding tray 101a. Subsequently, the feed roller 32a transfers the sheet to the transport roller 112.
conveyed to a. Finally, the conveying roller 112a sends out this sheet to the copying machine main body.

In some cases, the pickup roller 31a
May send out multiple sheets at once. Even in such a case, the retard roller 33a
In order to prevent feeding of subsequent sheets, only the uppermost sheet is conveyed thereafter.

In Japan, since the sheets of the A series and the B series are mixedly used, many trays for loading the sheets are often required. Further, even when sheets of the same size are used, a normal sheet may be inserted in one stage and color paper may be inserted in another stage, and the color paper may be used as a slip sheet. Under such circumstances, in an apparatus for domestic use in Japan, the optional side tray is often configured in multiple stages.

[0009]

As the number of optional side trays increases, a greater number of rollers, which are consumable parts, are used. Therefore, there was a disadvantage that running cost was high.

Further, the performance of the roller sheet feeding device largely depends on the friction coefficient of the roller surface. Therefore, there are drawbacks in that the paper feeding performance is not stable due to a change in the roller material over time, a change in the friction coefficient of the roller surface due to the adhesion of paper powder, and the like, and the sheet cannot cope with various sheets having different surface properties.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a paper feeder which is optionally attached to an image forming apparatus and has excellent durability and paper feed performance.

[0012]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and a first aspect of the present invention is directed to an image forming apparatus having a sheet feeding device which can be attached to and detached from an image forming apparatus main body. The sheet feeding device includes a sheet stacking unit on which sheets are stacked, a sheet floating unit that floats an upper sheet by blowing air to an end of the sheet stacked on the sheet stacking unit, and a conveyance belt. Have
An image forming apparatus is provided which includes a sheet feeding unit including a suction conveyance unit that suctions and conveys an uppermost sheet to the conveyance belt.

It is preferable that the paper feeding device has a plurality of paper feeding means.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the present embodiment is an image forming system including an image forming apparatus main body 1 and a sheet feeding device 2 that is optionally mounted on the image forming apparatus main body 1. Since the image forming system mainly has a feature in the sheet feeding device 2, the description here will be focused on the sheet feeding device 2.

The paper feeding device 2 is of an air separation type,
This is a type in which the sheets are separated and fed sequentially from the top sheet. As shown in FIG. 2, the sheet feeding device 2 includes a sheet storage unit 100 (100a, 100b,
100c), a sheet suction / conveyance unit 102 (102a, 102b, 102c) for separating and conveying the sheet, and a separation unit 103 (103a, 103b, 10) for separating the sheet.
3c), the transport rollers 112 (112a, 112b, 1)
12c), a connection mechanism 152 and the like are provided.
Further, a housing 150 accommodating the above-described parts is provided.

The sheet storage unit 100 (100a, 100
b, 100c) is a paper feed tray 101 (101a, 1c).
01b, 101c) and the sheet guide frame 125 (125
a, 125b, 125c) and the sensor 115 (115
a, 115b, 115c) and the sensor lever 114 (1
14a, 114b, 114c) and the like.

The paper feed tray 101 (101a, 101b,
101c) is for stacking sheets. The paper feed tray 101 is configured such that its vertical position is adjusted so that the upper surface of the stacked sheets S is maintained at a predetermined height position. The position adjustment is performed by a sensor 115 (115a, 115b, 11
5c) and the sensor lever 114 (114a, 114
b, 114c), the control device 50
Tray motor (not shown) that raises and lowers the paper feed tray 101
It is done by controlling the rotation of the.

The sheet guide frame 125 (125a, 125
(b, 125c) is for positioning the sheet S with the end of the sheet S placed on the sheet feed tray 101 abutting.

The sensor 115 (115a, 115b, 11
5c) and the sensor lever 114 (114a, 114
b, 114c) are for detecting the height of the upper surface of the sheet S placed on the tray. Sensor lever 1
14 operates in accordance with the height position of the upper surface of the sheet S, and the operating state (the position of the sensor lever 114) is
Detects whether the upper surface of the sheet S has reached a predetermined height position. The detection result (ON / OFF) of the sensor 115 is transmitted to the control device 5
0 is used to adjust the height position of the paper feed tray 101 described above.

The sheet suction / conveyance section 102 (102a, 10a)
2b and 102c) are for feeding the sheets stacked on the paper feed tray 101. FIGS. 3 and 4 show the details of the sheet suction and conveyance unit 102a. The sheet suction conveyance units 102b and 102c have the same configuration.

The sheet suction conveyance section 102 (102a, 1
02b, 102c) is the transport belt 106 (106a, 102c).
106b, 106c), drive unit 12, suction duct 11
(11a, 11b, 11c), the ejection duct 10 (10
a, 10b, 10c) and the like.

The transport belt 106 (106a, 106b,
106c) is arranged above the paper feed tray 101 with the paper feed direction side slightly upward. The transport belt 106 (106a, 106b, 106c) is wound around a driving roller 130 and a driven roller 131, and is driven by the driving roller 130 (130a, 130b, 130c).
It is designed to be rotated in the direction of arrow B with the rotation of c) (see FIG. 3). Further, on the surface thereof, a suction hole 105 for sucking and sucking the sheet is formed.

The drive section 12 operates the transport belt 106 by rotating a drive roller 130. As shown in FIG.
0, a gear pulley 111, a clutch 139, and the like. The driving force of the motor 140 is
1, to the input shaft of the clutch 139 via the belt 141. The output shaft of the clutch 139 is connected to the drive shaft 132 of the drive roller 130. Therefore, by connecting the clutch 139 by the control device 50, the driving force of the motor 140 is transmitted to the driving roller 130 via the driving shaft 132 to rotate the transport belt 106.

The suction duct 11 (11a, 11b, 11
c) is for sucking air through the suction holes 105 of the conveyor belt 106, and is arranged in the track of the conveyor belt 106. By operating a fan 107 to be described later and sucking air through the suction duct 11, a negative pressure is generated near the suction hole 105.
Further, in the suction duct 11, a suction valve 122 (122a, 122b, 122) for adjusting the amount of air suction is provided.
c) is arranged. The air sucked by the action of the fan 107 is flowed to the separation unit 103 and is jetted.

The separation unit 103 (103a, 103b, 10
3c) assists the suction conveyance of the sheet by blowing air to the end of the sheet to cause the sheet to float and separate. Separation unit 103 (103a, 103b, 103c)
Is provided with an ejection duct 10 (10a, 10b, 10c), a valve 123 (123a, 123b, 123c), a relay duct 88, a fan 107, and the like.

The ejection duct 10 (10a, 10b, 10
c) is disposed downstream of the paper feed tray 101 in the paper feed direction and below the drive roller 130. Spout duct 10
(10a, 10b, 10c) have arrows C in FIG.
Nozzle 108 that ejects air in the horizontal direction
And a separation nozzle 109 for ejecting air in the direction of arrow D. Air blown from the separation nozzle 108 and the separation nozzle 109 is supplied from the fan 107 through the relay duct 88. Spout duct 10
A valve 123 (123a, 123b, 123b) for adjusting the air ejection amount
c) is arranged (see FIG. 4). This valve 123
Can be adjusted in its opening in accordance with an instruction from the control device 50.

The fan 107 is driven by a motor (not shown) which operates according to an instruction from the control device 50. The fan 107 is also connected to the above-described suction duct 11, as shown in FIG. That is, the fan 107
Are used for suction in the suction conveyance section 102 and for the separation section 103.
It also has a configuration that also serves as a blower. FIG. 5 shows the flow of air between the suction duct 11 and the ejection duct 10.

In the case where such a configuration is adopted, depending on the case, it may be considered that the air to be ejected from the ejection duct 10 is not enough just by performing suction suitable for attracting the sheet. Further, there is a case where only the ejection of air from the ejection duct 10 is desired to be performed without performing the suction in the duct 11. Therefore, the suction duct 11 is opened on the upstream side of the suction opening 104 and is open to the atmosphere. The relief valve 20 (20a, 20b, 20c) is provided downstream of the opening. The relief valve 20 normally closes this opening of the suction duct 11 by its own weight. However, when the negative pressure in the suction duct 11 becomes equal to or higher than a predetermined value, the suction duct 11 is opened to the atmospheric pressure and the atmosphere is introduced into the suction duct 11. That is, the relief valve 20 plays a role as a constant pressure valve.

The transport rollers 112 (112a, 112b,
Reference numeral 112c) is for conveying the sheet conveyed by the suction conveyance unit 102 to the image forming apparatus main body 1, and is installed downstream of the sheet suction conveyance unit 102 in the sheet feeding direction.

The connection mechanism 152 is for mounting the paper feeding device 2 to the image forming apparatus main body 1. The connection mechanism 152 is provided in the housing 150, and operates in cooperation with the connection mechanism of the image forming apparatus main body 1 to mechanically connect the two. The connection mechanism 152 includes the control device 50 and the image forming apparatus main body 1.
A signal line connector for transmitting / receiving a predetermined control signal to / from a control device (not shown) is also provided.

The control device 50 controls and controls the entire sheet feeding device 2. The control device 50 has a function of performing a sheet feeding operation by operating each unit according to an instruction from the image forming apparatus main body 1.

The “sheet stacking section” in the present invention corresponds to the sheet feed tray 101 in the present embodiment. “Sheet lifting means” refers to the separation unit 103 and the control device 50.
Has been realized. The “suction conveyance unit” is realized by the sheet suction conveyance unit 102 and the control device 50. “Connection means” corresponds to the connection mechanism 152.

Next, the paper feeding operation will be described.

As a matter of course, the connection mechanism 15 of the paper feeding device 2
The paper feeder 2 is mounted on the image forming apparatus main body 1 by the connection mechanism 2 (not shown) of the image forming apparatus main body 1 with the connection mechanism 2.
Further, the sheets S are stacked on the sheet feed tray 101.

The control device 50 controls the sheet feeding tray 101 in accordance with the detection results of the sensor lever 114 and the sensor 115.
Is maintained, the interval between the sheet suction conveyance unit 102 and the top sheet S1 of the sheet S is kept constant.

When a copy start signal is input from the image forming apparatus main body 1, the control device 50 operates the fan 107 and the motor 140. Further, the valve 123 corresponding to the paper feed tray 101 selected at that time is opened, and air is supplied to the ejection duct 10. As a result, air is blown from the separation nozzle 108 and the separation nozzle 109 in a predetermined direction. Here, it is assumed that the sheet S stored in the sheet feeding tray 101a is fed.

At this time, the air blown out from the separation nozzle 108a enters between the sheets S, so that the upper parts of the sheets S are floated while being separated (see FIG. 3).

Next, the control device 50 controls the suction valve 122
Open a. Then, a negative pressure is generated in the suction duct 11a, and the uppermost sheet S1 of the sheets S floating by the air from the separation nozzle 108a is adsorbed on the surface of the transport belt 106a. At this time, the sheet S2 located below the sheet S1 may be sucked together. However, the air ejected from the separation nozzle 109a flows between the sheet S1 and the sheet S2, so that the sheet S2 is pushed back.

Next, the control device 50 connects the clutch 139 and starts the rotation of the transport belt 106a. As a result, the sheet S1 adsorbed on the transport belt 106a is
Conveyed in the paper feed direction. Thereafter, when the leading end of the sheet S1 reaches the transport roller pair 112a, the control device 50
Turns off the clutch 139 to stop the transport belt 106a.

Then, the conveying roller pair 112a sends out the sheet S1 to the image forming apparatus main body 1 through the paper feeding port 151 of the housing 150.

Thereafter, the sheet is transferred to the image forming apparatus main body 1.
An image is formed in an image forming unit provided therein and is discharged.

The sheet feeding device of the embodiment described above separates and feeds the sheet by using air, so that it is not affected by paper dust or the like. Further, the influence of the properties of the sheet surface is small.

The control device 50 performs the sheet feeding operation in accordance with an instruction from the main body 1 of the image forming apparatus. However, the control device of the image forming apparatus main body may control the sheet feeding device.

[0045]

As described above, the paper feeding apparatus of the present invention employs an air paper feeding system in which sheets are separated and fed by using air, so that it is almost unnecessary to replace parts regularly. And excellent in durability. Further, the configuration of the device itself is simple, and the reliability is high.

[Brief description of the drawings]

FIG. 1 is an external view of an image forming apparatus equipped with a sheet feeding device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a configuration of a sheet feeding device of the present invention.

FIG. 3 is a schematic side view illustrating a configuration of a sheet feeding unit.

FIG. 4 is a schematic top view illustrating a configuration of a sheet feeding unit.

FIG. 5 is a schematic diagram showing an air supply system.

FIG. 6 is a schematic diagram showing a conventional sheet feeding device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Image forming apparatus main body 2 Paper feeder 10 (10a, 10b, 10c) Spout duct 11 (11a, 11b, 11c) Suction duct 20 (20a, 20b, 20c) Relief valve 50 Control device 88 Relay duct 100 (100a, 100b) , 100c) Sheet storage unit 101 (101a, 101b, 101c) Paper feed tray 102 (102a, 102b, 102c) Sheet suction / conveyance unit 103 (103a, 103b, 103c) Separation unit 105 Suction hole 106 (106a, 106b, 106c) Conveying belt 107 Fan 108 Separation nozzle 109 Separation nozzle 111 Gear pulley 122 (122a, 122b, 122c) Suction valve 123 (123a, 123b, 123c) Valve 132 Drive shaft 139 Clutch 140 Motor 141 bell 150 enclosure 152 connection mechanism S1, S2 sheet

Claims (2)

[Claims] 1. An image forming apparatus having a sheet feeding device detachable from a main body of the image forming apparatus, wherein the sheet feeding device includes: a sheet stacking unit on which sheets are stacked; and sheets stacked on the sheet stacking unit. A sheet levitation unit that floats an upper sheet by blowing air to an end of the sheet feeding unit, and a suction conveyance unit that has a conveyance belt, and suctions and conveys the uppermost sheet to the conveyance belt. An image forming apparatus comprising: 2. The image forming apparatus according to claim 1, wherein the sheet feeding device has a plurality of sheet feeding units.