JPH1138696A - Automatic document feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device in which a document can be surely ejected to a restricted space without largely protruding a paper ejection unit holding an ejecting document from a device main body and to provide a device in which the deformation of the document and the inconvenience of a copied image caused by a faulty stop position are evaded in a copying device or the like using an automatic document feeder. SOLUTION: This device is provided with an electrifying roller 27 giving an electric charge to an ejecting document. By making the ejecting document adsorb to a dielectric belt 21, the ejecting document is ejected on a document table 28. Thus, a large-sized paper ejection unit is not needed to be provided outside the device. Besides, by making a document scale 102 elevate and lower, at the time of an abutting mode, the document is surely stopped by elevating the scale 102 and at the time of a non-abutting mode, the adhesiveness of the end part of the document to the upper surface of a contact glass 101 is improved by lowering the scale 102 lower than the glass 101. Thus, the excellent image is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an automatic document feeder in an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, an automatic document feeder has a paper feed / discharge port on the same side and a different type as in the present invention. If the paper supply / discharge port is different, the paper supply port or the paper discharge port must be moved according to the size of the document.

For example, when copying a large-sized document by a copying machine using an automatic document feeder, there is a problem that the paper discharge unit protrudes largely from the copying machine body and the installation space becomes large. there were. In addition, an automatic document feeder having an abutting mode and a non-abutting mode is mainly used.

In the abutting mode, as shown in FIG.
An operation such as sending out by 5 mm and returning by 10 mm from the reference of 2 is performed. For this reason, as shown in FIG. 6, the original 200 having a weak stiffness buckles in the triangular gap on the original scale 202, the conveyor belt 203, and the contact glass 201. The optical path length of the photoreceptor changes, and an appropriate image cannot be obtained on the photoreceptor, and an image in which characters and straight lines are bent at the ends is formed.

In the non-colliding mode, the original 200
Although the document itself can be prevented from being damaged, the document scale 202 is only stopped at the reference position on the contact glass 201. Therefore, as shown in FIG. Is manuscript scale 20
Since the exposure is performed while remaining on the surface 2, there is a problem that a good image cannot be obtained as described above.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a method for accurately ejecting a paper at an arrangement position easily adjusted to the size of the original without increasing the installation space by adsorbing the discharged original by using an electrostatic field. The purpose is to do. Also,
When the non-collision mode is selected, the original scale is retracted below the upper surface of the contact glass during exposure, eliminating steps, improving the adhesion of the original end to the upper surface of the contact glass, and improving image quality. It is an object of the present invention to provide an automatic document feeder capable of obtaining the same.

[0007] Further, the pressing rollers ensure the adhesion of the end portions more reliably, and the load on the conveyor belt driving motor can be reduced by operating only when the pressing rollers are required. .

[0008]

According to the first aspect of the present invention,
To achieve the above object, the original set on the original table is fed and separated, conveyed to a predetermined position on the contact glass of the copying machine, copied, and then discharged again to the set position on the original table. An endless dielectric belt that applies a charge to the discharged document, adsorbs and transports the separated document, and a separation claw that peels the discharged document from the dielectric belt. And a document fence for fixing the document to be fed at a sheet feeding position.

According to a second aspect of the present invention, in the automatic document feeder according to the first aspect, the document fence includes a document side fence for fixing both end positions and a document end for fixing a depth position. A fence; and detecting means for detecting the position of the document fence, wherein the separating claw is moved in accordance with the detection position detected by the detecting means.

According to a third aspect of the present invention, in the automatic document feeder according to the second aspect, when the detecting means detects a maximum document size, the dielectric belt does not give a charged charge. It is characterized by the following. According to a fourth aspect of the present invention, in order to attain the above object, the automatic document feeder according to any one of the first to third aspects has a paper discharge sensor above the document fence. .

According to a fifth aspect of the present invention, in order to achieve the above object, a document conveyed onto a contact glass by a conveyance belt is abutted against a document scale, the conveyance is corrected, and the document is set on a reference glass on a contact glass. Selection means for selecting a butting mode for stopping at a position, and a non-butting mode for stopping the document at a reference position on a contact glass without abutting the document scale, and elevating means for raising and lowering the document scale. When the hitting mode is selected according to the mode selected by the selecting means, the elevating means causes the original scale to protrude from the upper surface of the contact glass, and the non-hitting mode is selected. When the leading edge of the document is lowered from the upper surface of the contact glass in accordance with the timing of the document being conveyed onto the contact glass. A.

According to a sixth aspect of the present invention, in the automatic document feeder according to the fifth aspect of the present invention, a pressing roller for pressing a conveying belt is provided above an end of a reference position on the contact glass of the original scale. Are arranged. According to a seventh aspect of the present invention, in order to achieve the above object, in the automatic document feeder according to the sixth aspect, the pressing roller has a pressure releasing mechanism, and the selecting means selects a butting mode. When the pressure is released,
When the non-collision mode is selected, pressure is applied in accordance with the timing when the document scale is lowered.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 4
The configuration operation will be described with reference to FIG. 1 is an overall configuration diagram of the present invention, FIGS. 2 and 3 are configuration diagrams of a belt unit above an original table, and FIG. 4 is a diagram showing a mechanism diagram of an original scale.

As shown in FIG. 1, this apparatus provided with an automatic document feeder includes a vacuum tank 2, a paper feed belt 3, a side fence 4, an end fence 5, an air knife 6,
Paper feed belt drive roller 7, pull-out roller 8, entrance sensor 9, switchback roller 10, branch claw 11, registration roller 12, switchback sensor 13, registration sensor 14, transport belt drive roller 15, transport belt 1
6, relay sensor 17, relay roller 18, paper discharge roller 1
9, a paper ejection sensor 20, a dielectric belt 21, a dielectric belt driving roller 22, a separating claw 23, a timing belt 24,
Belt drive pulley 25, charging brush 26, charging roller 2
7, a document table 28, a document table cover 29, a potentiometer 31, a scale pressing roller 32, a scale pressing roller 33, a driven roller 34, a paper discharge sensor 54, a contact glass 101, and a document scale 102.

First, the document table cover 29 is opened in the direction of the arrow in FIG. 1, the document bundle 1 is turned upside down, and the side fence 4 and the end fence 5 are placed on the document table 28.
And set. At this time, the dielectric belt 21 and the like are installed on the original table cover 29 side and are simultaneously avoided. Each of the side fence 4 and the end fence 5 is connected to a potentiometer (sliding type variable resistor) 31 to detect the width and length of each set document and automatically determine the size of the document. I have.

When the document table cover 29 is returned to its original position and the start key is pressed, the separating claw driving motor 51 is rotated in accordance with the position of the potentiometer 31, and is engaged with the timing belts 24a and 24b at the discharge position. The separation claws 23a and 23b stop. Further, a fan motor (not shown) is rotated, and compressed air is blown from the nozzle of the air knife 6 from the leading end of the document bundle 1 to bring the document up. At this time, when a suction force is applied from the vacuum tank 2, only the lowermost document is attracted to the paper feed belt 3. (A plurality of holes are formed in the paper feed belt 3.) When the paper feed belt 3 is driven to rotate counterclockwise in this state, only the lowest document is pulled out.

Next, when the entrance sensor 9 detects that the original has been added to the pull-out roller 8, the paper feed belt driving roller 7 is turned off, and at the same time, the suction force of the vacuum tank 2 is shut off by the valve. No conveyance force is applied to the next original. Thus, the sheet feeding / separating operation is completed.

Subsequently, in the case of a one-sided original, the branch claw 1
When the registration sensor 14 detects the trailing edge of the document via the registration roller 12 through the outside of the contact glass 101, the conveyance belt 16 conveys the document by a predetermined number of pulses, and the contact glass 101.
Set on top. In the case of a double-sided document, the document is conveyed to the switchback path above the conveyance belt 16 by the switchback roller 10 through the upper side of the branch claw 11, and when the switchback sensor 13 detects the rear end of the document, only the switchback roller 10 It is driven to rotate in the reverse direction, passes under the branch claw 11, and is held by the registration roller 12.

Next, when the registration sensor 14 detects the trailing edge of the original when the abutting mode is selected, the transport belt 1
6, the pulse is sent out so that the rear end is separated from the original scale 102 by a predetermined number of pulses, and then the transport belt 16 rotates in the reverse direction to return the original 1 more than the number of pulses sent from the original scale 102. Then, it is set to a reference position on the contact glass 101 by correcting the skew with the original scale 102.

When the non-butting mode is selected, when the registration sensor 14 detects the trailing edge of the document, the keep solenoid 60 shown in FIG. By being retracted to the lower side, the original scale 102
The level difference between the document set reference side end and the contact glass 101 disappears, and the transport belt 16 comes into close contact with the contact glass 101. Then, the original 1 is fed by a predetermined number of pulses to the reference position of the contact glass 101 and stops. Here, the scale pressing roller 32 disposed on the upper portion of the original scale 102 exerts a force in a direction in which the conveying belt 16 is brought into close contact with the contact glass 101 at the same time as the original scale 102 is retracted. Be more certain.

By providing a scale pressing roller releasing mechanism shown in FIG. 4B, normally, the pressure retreat state is maintained, and the DC solenoid 65 is turned on at the timing when the document scale 102 is retreated. Thereby, the transport belt 16 is pressed. Therefore, it is not normally pressurized, and it is possible to prevent the load current of the drive motor from increasing due to the increase in the contact force between the edge portion of the document scale 102 and the transport belt 16 caused by adding the release mechanism.

The timing for retracting the original scale 102 may be any time before the leading edge of the original 1 enters the contact glass 101 and the exposure is started. The same applies to the timing of pressing by the scale pressing roller 32. When the exposure of the document 1 is completed, the keep solenoid 60 is turned ON at this time, the document scale 102 returns to the original position, and the next document can be received.
At the same time, by turning off the DC solenoid 65, the pressure of the scale pressing roller 33 is released.

The copied original is transferred to a transport belt 16.
, And is passed through the relay roller 18 and the paper discharge roller 19, and is attracted from the leading end of the document by alternating electrolysis to the dielectric belt 21 to which positive and negative charged charges are applied in stripes by the charging rollers 27 a and 27 b. At this time, the dielectric belt 2
When the document 1 is rotated, the document is conveyed in a state of being sucked, the leading edge of the document is scooped up by the separating claw 23, and is peeled off from the dielectric belt 21 from the leading edge. The paper is ejected on top.

The surface of the charging roller 27 is a thin human phosphorus rubber layer to which an applied voltage is applied. The dielectric belt 21 is a thin resin, and the front surface is an insulating layer and the back surface is a conductive layer. A paper discharge sensor 54 is provided above the end fence 5 to detect a jam.

When it is detected that the document is the maximum document by the position of the end fence 5, the dielectric belt 21 is not charged, the rotation is not performed, and the separation claw 2 is not driven.
3 is also the position of the home position (Figure 1: Position of the chain line)
The paper is discharged only by the paper discharge roller 19 without being moved. Therefore, power is not consumed more than necessary.

[0026]

According to the first aspect of the present invention, since the paper can be discharged with a simple configuration, it does not become an obstacle when setting an original, and there is no need for a guide plate or the like to be inserted when a jam occurs. Therefore, it can be easily processed simply by peeling it off the belt. In addition, since the discharged original can be attracted to the dielectric belt and discharged, the discharge position can be set to a desired position, and a large discharge space is not required outside the apparatus, and the apparatus is made compact. be able to.

According to the second aspect of the present invention, since the separation claw can be moved in accordance with the size of the document, the discharged document can be peeled from the dielectric belt according to the size of the document, and the separation claw can be separated. Since it is a movable type, it can deal with an original of an irregular size. According to the third aspect of the present invention, when the original is the maximum size, no charged electric charge is given, so that unnecessary power consumption is not used.

According to the fourth aspect of the present invention, since the paper discharge sensor checks the paper discharge state, it is possible to reliably detect a stack failure jam. According to the fifth aspect of the present invention, when the abutment mode is selected, since the original scale is higher than the original transport position, the original can be reliably abutted against the original scale and the original can be stopped. It can be reliably stopped at the position. Further, when the non-collision mode is selected, the contact glass and the conveyance belt can be in close contact with each other, so that the original can be reliably pressed by the conveyance belt, and a good image free of straight-line bending and character distortion can be obtained.

According to the sixth aspect of the present invention, since the conveying belt is pressed by the pressing roller, in addition to the above-described effects, the original can be reliably pressed by the conveying belt, and linear bending and character distortion can be prevented. No good images can be obtained. According to the seventh aspect of the present invention, when the normal butting mode is selected, the pressurization is released, so that it is not necessary to increase the load current for the pressurization. There is no need to deal with. Also, if the pressurized state is always applied, the edge of the original scale will be worn more, and the scale will run up when the original is abutted when the abutment mode is selected. Riding can be prevented.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of an automatic document feeder according to the present invention.

FIG. 2 is a configuration diagram of a belt unit according to one embodiment.

FIG. 3 is a configuration diagram of a belt unit according to one embodiment.

FIG. 4 is a mechanism diagram of an original scale according to one embodiment.

FIG. 5 is an explanatory diagram of an operation in a butting mode.

FIG. 6 is a diagram illustrating a state of a document in a document scale unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Original 2 Vacuum tank 3 Feed belt 4 Side fence 5 End fence 6 Air knife 7 Feed belt drive roller 8 Pull-out roller 9 Inlet sensor 10 Switchback roller 11 Branch claw 12 Registration roller 13 Switchback sensor 14 Registration sensor 15 Transport belt Driving roller 16 Conveying belt 17 Relay sensor 18 Relay roller 19 Discharge roller 20 Discharge sensor 21 Dielectric belt 22 Dielectric belt drive roller 23 Separation claw 24 Timing belt 25 Belt drive pulley 26 Slow-brush brush 27 Charging roller 28 Original table 29 Document table cover 31 Potentiometer 32 Scale press roller 33 Scale press roller 34 Follower roller 50 Dielectric belt drive motor 51 Separation claw drive motor 52 Cupri Grayed 53 separating pawl home position sensor 54 conveying belt discharge sensor 60 keep solenoid 61 spring 62 the lever 65 DC solenoid 66 arm 67 spring 68 return spring 101 contact glass 102 document scale 200 original 201 contact glass 202 document scale 203

Claims (7)

[Claims] An original set on an original table is fed and fed.
After being separated, conveyed to a predetermined position on the contact glass of the copying machine, copied, and then discharged again to the set position on the document table, the circulating automatic document feeder charges the discharged document. An endless dielectric belt that gives an electric charge, adsorbs and transports the paper, a separation claw that peels off the discharged original from the dielectric belt, and an original fence that fixes the original to be fed at a paper feeding position. An automatic document feeder comprising: 2. The automatic document feeder according to claim 1, wherein the document fence comprises: a document side fence for fixing both end positions; and a document end fence for fixing a depth position. An automatic document feeder, comprising: detection means for detecting, wherein the separation claw is moved in accordance with a detection position detected by the detection means. 3. The automatic document feeder according to claim 2, wherein said dielectric belt does not apply a charge when said detecting means detects a maximum document size. 4. The automatic document feeder according to claim 1, further comprising a paper ejection sensor above the document fence. 5. An abutment mode in which a document conveyed onto a contact glass by a conveyance belt is abutted against a document scale, the conveyance is corrected, and the document is stopped at a reference position on the contact glass. Selecting means for selecting a non-abutting mode for stopping at a reference position on the contact glass without abutting on the original scale; and elevating means for elevating and lowering the original scale, wherein the elevating means comprises the selecting means When the contact mode is selected according to the selected mode, the original scale is made to protrude from the upper surface of the contact glass. When the non-contact mode is selected, the leading edge of the original is conveyed onto the contact glass. An automatic document feeder, which is lowered from the upper surface of the contact glass in accordance with the timing. 6. The automatic document feeder according to claim 5, wherein a pressing roller for pressing a conveyor belt is disposed above a reference position end of the document scale on the contact glass. . 7. The automatic document feeder according to claim 6, wherein said pressing roller has a pressurizing release mechanism, and said selecting means releases pressurizing when the abutment mode is selected. An automatic document feeder characterized in that when the non-butting mode is selected, pressurization is performed in accordance with the timing at which the document scale is lowered.