JPH0952640A - Document conveying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a document conveying device having a simple structure, a small scale, and good operability at a low cost. SOLUTION: A roller electrifying brush 41 is arranged in parallel and in contact with the upper section of a conveyance roller 34, and document de- electrifying brushes 42, 43 are arranged in parallel at the front and rear of the conveyance roller 34. A DC voltage is applied to the roller electrifying brush 41, and the tip of the brush 41 is brought into contact with the conveyance roller 34 to electrify it. A peeling pawl 44 for peeling a document from the surface of the conveyance roller 34 and the document de-electrifying brush 42 are arranged near the document cover 3 side of the conveyance roller 34. A peeling pawl 45 and the de-electrifying brush 43 are likewise fitted to a conveyance guide and arranged near the operation panel 22 side of the conveyance roller 34.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document conveying device mounted on an image forming and reading device such as a copying machine, and more particularly to a document conveying device for carrying an externally inserted document into or out of the device. Is.

[0002]

2. Description of the Related Art FIG. 12 is a block diagram showing a conventional document feeder, showing a conventional example mounted on a document cover of a copying machine (see Japanese Patent Laid-Open No. 6-67497). In the figure, the document feeder 102 is mounted on a document cover 126 which is supported to be openable and closable about a shaft 125.
A document tray 130 using the upper surface of the document cover 126,
An original roller 131 for feeding the original D from the original tray 130, a paper feeding roller 132, a guide plate 133 for guiding the original D to the exposure section A on one side of the exposure glass 120 serving as the original table, and the original on the exposure section A. Discharge roller 1 that conveys D
It has 36 etc.

In this structure, when the document feeding device 102 is operated, the document D is fed from the document tray 130, and the document D is fed by the feeding roller 134 and the driven roller 1.
37 is conveyed while being bitten by 37, and is discharged by the discharge roller 136.
And then discharged to the discharge tray 135. At this time, the optical system 121 moves the copy lamp 122 directly below the conveyance roller 134, and copies the document D while passing the exposure area A of the exposure glass 120 with the optical system 121 fixed.

[0004]

However, in this document feeder, the document is conveyed in a state where the document is bitten into the conveying roller 134 and the driven roller 137, and two rollers are required, and two rollers are required. A constant pressure is applied so that they contact each other. Therefore, the structure becomes complicated, and it is difficult to reduce the scale and the cost.

An object of the present invention is to provide a document feeder which is simple in construction, small in scale, inexpensive in cost and good in operability.

[0006]

SUMMARY OF THE INVENTION The present invention is a document feeder for use in a device that exposes a document, forms an image of the document, and reads the document, and a transport roller that attracts and transports the document by charging. The present invention is characterized by comprising: roller charging means for charging the conveying roller; peeling means for peeling the original adsorbed on the conveying roller from the conveying roller; and original discharging means for removing electric charge from the peeled original.

The roller charging means may be a means for charging the charging roller by bringing the charging material into contact with a rotating conveying roller.

In addition to the above configuration, the present invention may include means for detecting a paper jam of the document, and roller discharging means for discharging the electric charge from the conveying roller when the paper jam of the document is detected. In this case, the roller charging means is a means for applying a DC voltage to the conductive brush that is in contact with the surface of the carrying roller, and the roller charge eliminating means switches the DC voltage to the reverse voltage of the roller charging means and applies the DC voltage to the conductive brush. It may be a means. Further, the roller charging means is a means for applying a DC voltage to the conductive brush in contact with the surface of the conveying roller, and the roller discharging means is a means for switching the DC voltage to the conductive brush and connecting the ground. Good.

In the present invention, the original is attracted to the conveying roller by using the electrostatic force generated by charging the conveying roller, and the original is conveyed by the rotation of the roller. Therefore, only one roller is required, and a complicated structure for bringing two rollers into contact with each other to apply pressure, which is required in the past, is unnecessary. Therefore, a small-scale and inexpensive device can be realized. Further, when a paper jam occurs, if the electric charge of the transport roller is removed, the electrostatic force disappears, and the jammed document can be easily removed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. <Internal Structure of Copying Machine> FIG. 1 is a sectional view showing the internal structure of a copying machine provided with the document feeder of the present invention, and FIG. 2 is a perspective view showing its appearance. This copier is a copier body 1
A document table 2 made of transparent glass for image exposure is provided on the upper part of the table. A document cover 3 is arranged above the document table 2 so that it can be raised and lowered. An optical system 4 is arranged inside the copying machine body 1 below the document table 2. The manuscript cover 3 is for pressing a manuscript placed on the manuscript table 2. The manuscript cover 3 opposes the manuscript table cover 2 inside the exterior 3a of the manuscript cover 3 which is made of a relatively hard plastic resin. A document holding mat 3b formed of a relatively soft member is attached to the lower surface.

The optical system 4 includes a light source lamp 4a for optically scanning a document placed on the document table 2, mirrors 4b, 4c and 4d for guiding reflected light from the document and mirrors 4b-4b.
The lens 4e collects the reflected light that has passed through d, and the mirrors 4f, 4g, and 4h that guide the collected reflected light to the exposure point on the surface of the photosensitive drum 5 installed in the central portion of the main body.

The photosensitive drum 5 is for forming an image of a document placed on the document table 2. Around the photoconductor drum 5, a charger 6 for uniformly charging the surface of the photoconductor drum 5, a developing device 7 for developing the electrostatic latent image after exposure with colored toner, and a sheet-like sheet which is appropriately conveyed. Transfer device 8 for transferring the toner image formed on the paper, cleaning device 9 for removing the toner remaining after the transfer,
A charge eliminating lamp 10 for uniformizing the potential on the surface of the photoconductor in order to repeatedly use the photoconductor drum 5 is arranged in the order described above. A copying process system is formed by each of these devices.

Separately from the copying process system for image formation, the paper is conveyed to the toner transfer position of the transfer unit 8, and after the image is transferred, the paper is peeled off and the main body of the copying machine 1 is removed. A paper transportation system for discharging the paper is provided inside the copying machine. The transport system includes a paper feed unit that feeds paper, a transport unit that conveys the fed paper to the above-mentioned transfer position, and a carry-out unit that carries out the paper after transfer to the outside of the copying machine main body 1. With.

The above-mentioned paper feed unit is a paper storage unit (paper feed cassette) detachably provided at the bottom of the copying machine main body 1.
11 and a paper feed tray 12 for manual insertion, which is projected from the copying machine main body 1 to the outside.

A half-moon-shaped sheet feeding roller 13 is arranged at the upper front end (right side in the figure) of the sheet storing section 11, and the sheet feeding roller 13 is a copy sheet stored in the sheet storing section 11. Feed P one by one from the top. Particularly, in the paper storage unit 11, a rotary member 11a for mounting the paper P on the upper surface thereof is rotatably provided, and a spring (not shown) is pushed up by a biasing force and is fixed by a separation claw 11b which enables single paper feeding. This is a configuration for positioning the uppermost sheet stored at the height of.

Also in the paper feed tray 12, a paper feed roller 14 for invoking one or a plurality of papers placed thereon, and a paper feed roller 15 for preventing the feeding of two invoked papers,
In the feeding mechanism including the separating member 16, a sheet feeding unit that sequentially feeds the sheets one by one according to a sheet feeding command is provided.

The transport unit that transports the sheet fed through the sheet feeding unit having the above-described configuration to the transfer position next has a pair of transport rollers 17 and 18. A paper top plate 19 is provided on the downstream side of the carrying roller 17 in the paper carrying direction.
The paper conveyed through is temporarily stopped. The paper top plate 19 causes the leading edge of the image formed on the photosensitive drum 5 to coincide with the leading edge of the sheet to be transported, and starts the transport. The transport top is released according to the rotational position of the photosensitive drum 5. The sheet is conveyed to the transfer position by the conveyance roller 17 and the conveyance roller 18 arranged immediately before the transfer position. By these means, copy paper P
Forms a sheet conveying unit that conveys the sheet to a transfer position facing the photosensitive drum 5.

The sheet P passing through the transfer position is separated from the surface of the photoconductor drum 5 and then passes through a heating and fixing device 20 disposed in the middle of a path for carrying it to the outside of the copying machine. The heating and fixing device 20 is composed of a pair of rollers, one of which is a heat roller and the other of which is a pressure roller which presses against the heat roller. The paper P is conveyed while being pressed, and unfixed on the paper by heat. The toner image is heated and fixed. The sheet of paper passing through the heat fixing device 20 is discharged to a discharge tray 21 which is detachably provided in correspondence with the discharge opening formed in the copying machine main body 1.

<First Embodiment> FIG. 3 is a schematic cross-sectional view showing a document detecting means and a conveying means of a first embodiment of a document conveying apparatus mounted on this copying machine. Further, FIG. 4 is a schematic sectional view showing a document cover fixing means and a document cover floating means of the document conveying apparatus.

First, as shown in FIG. 3, the original detecting means and the conveying means of the original conveying device are located below the front handle portion 31 of the original cover 3 and in front of the original pressing mat 3b. The document insertion slot 32 to be inserted, a detection lever 33 that is pushed up by the inserted document to turn on the document detection switch, a conveyance roller 34 that conveys the inserted document onto the document table 2, and the like. The original insertion port 32 is provided with the original cover 2 of the copying machine main body 1 and the original cover 3 for providing the original table 2 of the copying machine main body 1 on the upper portion.
Is formed between the handle portion 31 and the handle portion 31.

The conveying roller 34 is made of a material having a high dielectric constant such as epoxy, and the original table 2 and the operation panel 2 are used.
It is arranged on the plane portion of the above-described upper exterior portion 1a of the copying machine body 1 between the two. As shown in FIG. 5, the cylindrical conveying roller 34 has a bearing 45 and a roller stopper 46 at both ends thereof, and has a conveying roller gear 47 between the bearing 45 and the roller stopper 46 on one end surface. The conveying roller 34 has a rotation shaft rotatably supported on the document cover 3 side, and a rotational force from a drive motor (not shown) arranged in a part of the document cover 3 is transmitted via a roller gear 47. It is a configuration. The rotary shaft of the transport roller 34 is not grounded.

As shown in FIG. 6, roller charging brushes 41 are arranged in parallel so as to be in contact with the upper portion of the conveying roller 34, and original discharging brushes 42 and 43 are arranged parallel to the front and rear of the conveying roller 34 for discharging the original. To do. The roller charging brush 41 and the original discharging brushes 42, 43 are, for example, bundled of conductive fibers like a brush and arranged up to the length of the transport roller 41. For the roller charging brush 41, a supply line is drawn from the opening / closing shaft side of the document cover 3 into the document cover 3 for several Ks.
V DC voltage is applied. Then, the tip of the brush is brought into contact with the transport roller 34 to be positively charged. As shown in FIG. 6, a plate-shaped conveyance guide 48 that defines the conveyance direction of the document is provided with a peeling claw 44 for peeling the document from the surface of the conveyance roller and a document discharging brush 42. This is arranged near the document cover 3 side of the transport roller 34. Similarly, the peeling claw 45 and the static elimination brush 43 are also attached to the conveyance guide and arranged near the operation panel 22 side of the conveyance roller 34.

A detection switch and a detection lever 33 for detecting the insertion of a document into the transport area of the transport roller 34 are similarly arranged on the document cover 3 side. Then, when the document cover 3 is closed and pressed on the document table 2, the detection lever 33 enters a recess (not shown) formed in the upper exterior 1a of the copying machine main body 1,
The document to be inserted is raised above the outer casing 1a. As a result, the document detection switch is operated (ON) to detect the document.

In the document stocker 35, in order to float the document cover 3 and form a gap between the document pressing mat 3b and the document table 2, a shaft portion 35b is provided above the exterior 1a on the copying machine main body 1 side. As shown in FIG. 4, a levitation member 37 is provided at a position corresponding to. The floating member 37 slightly protrudes toward the operation panel 22 side, and the protruding end portion is formed with a curved portion 37a in a downward curved shape.

Corresponding to the floating member 37, a floating member 37 and an engaging portion 35d are formed on the original stocker 35 side. The engaging portion 35d is formed on the entire surface of the opening 35c of the document stocker 35, particularly in the vicinity of the shaft portion 35b, and has a convex shape that fits into the curved portion 37a of the floating member 37. . The levitation member 37 and the engaging portion 35d constitute a levitation mechanism.

Therefore, if the original stocker 35 placed on the original cover 3 is rotated to the front side and is rotated to a position where the original stocker 35 covers the operation panel 22, the original is stored. One end of the stocker 35 is the exterior 1
It is supported on the a plane and its rotation is restricted. As a result, the convex portion of the engaging portion 35d of the document stocker 35 engages with the curved portion 37a of the floating member 37 described above. At this time, one end of the peripheral edge forming the opening 35c of the document stocker 35 is supported on the exterior 1a of the copying machine main body 1, and the curved portion 37a of the levitation member 37 and the engaging portion 35d are engaged with each other, thereby causing the shaft portion. The document cover 3 is lifted upward via the 35b. That is, since the handle portion 31 on the opposite side of the rotatable shaft support portion on the back side of the document cover 3 is raised by the rotation of the document stocker 35, in particular, the shaft portion 35b is raised, the document cover 3
Is rotated and lifted up around the pivotal support portion of the document cover 3. Therefore, the document table 2 and the document pressing mat 3b
A gap d is formed between and.

Here, the gap d is the distance between the engaging portion between the levitation member 37 and the engaging portion 35c and the shaft portion 35b, and the angle (the straight line between the shaft portion 35b and the engaging portion and the document table). The angle formed by the horizontal plane 3) and the necessary gap d can be formed by setting these appropriately.

Further, the bent portion 3 of the original stocker 35
One side surface of 5a acts as a guide for guiding one side surface of the original to be inserted. That is, one end of the document has the other reference end orthogonal to the above-mentioned reference end 2a of the document table 2, and one side surface of the bent portion 35a of the document stocker 35 is formed so as to coincide with the reference end. Has been done. The side surface facing the bent portion 35a that coincides with the reference end is formed with a space large enough to accommodate the largest document.

Next, the operations of the document feeder and the main body of the copying machine will be described with reference to the flow chart shown in FIG. When the document cover 3 is closed and the document stocker 35 is opened and the document D is inserted from the document feed port 32, the detection lever 33 is pushed up by the document and the detection switch is turned on (step S1).

When the detection switch is turned on, the transport roller 3
A positive charge is applied to 4 by the charging brush 41 (step S2), the transport roller 34 starts positive rotation, and the entire transport roller 34 is uniformly charged (step S3). The document D is inserted between the document table 2 and the document pressing mat 3a, and the lower surface of the document pressing mat 3b functions as a document guide. Considering that a normal sheet has a thickness of about 0.08 mm, this gap is preferably 0.1 mm or more. When the document approaches the positively charged transport roller 3, a negative charge is induced on the document. Thus, as shown in FIG.
The document D is attracted to the transport roller 34 by electrostatic force and is attracted to the transport roller 34. Since the document D is attracted so as to be wrapped around the transport roller 34, the attraction surface with the document is widened, and an attracting force of about 100 g can be obtained with an applied voltage of about 10 KV. On the other hand, since there is almost no resistance in the document transport direction, a sufficient suction force can be obtained to transport the document.

The original that is attracted to and conveyed by the conveying roller 34 is peeled off from the conveying roller 34 by the peeling claw 44, and the charge removing brush 42 immediately after that removes the charge. This prevents the document from being attracted to the document cover 3 and the document table 2 due to the static electricity of the document when the document is inserted, and when the document D passes the detection lever 22 and the switch is turned off (step S4), the transport roller 34 is used. Stops (step S5),
The original stops when the rear end of the original is gripped by the conveyance roller 34.

When the original is automatically carried on the original table 2 in this manner, the copying machine starts a copying operation similar to the one in which the copy button 10a is pressed, and performs copying processing from exposure to discharge of copy paper (step). S6). When the copying process ends, the transport roller 34 rotates in the reverse direction (step S
7) The document is discharged to the document feed port 21. At this time, the discharging side discharging brush 43 removes the charge. For this ejection, the rotation time of the conveyance roller 34 at the time of inserting the document D is stored, and the elapse of a predetermined time set to be shorter than the stored time (for example, a conveyance distance of about 10 mm) is detected (step S8), the reverse rotation of the transport roller 34 is stopped (step S9). Since the document D stops while being slightly bitten by the transport roller 34, when another copy is desired again,
If the copy button is pressed within a certain period of time (for example, within 2 seconds) after the conveyance roller is stopped (steps S10 and S11), the conveyance roller 34 is rotated in the normal direction to enter the copy state again. This allows multiple copies to be taken.

After a lapse of a certain period of time, the conveying roller rotates again in the reverse direction (step S12), the document is discharged to the document stocker 24, and the document is stopped (step S13). After stopping the rollers, charging is stopped (step S14).

By charging the carrying roller 34 during the above series of operations, the carrying can be carried out by one roller. Further, by arranging the conveying roller 34 right above the original reference edge (glass edge) of the original table 2, it stops after the original is loaded, and the original end is the exposure end when the original end is caught by the roller. It can be set to the reference edge. To align the edges, there is a method of aligning the roller rotation time after the document detection switch is turned off. However, in the state where the upper and lower conveying rollers are bitten like the conventional conveying device, the portion of the document sandwiched by the rollers cannot be exposed, resulting in loss. On the other hand, in the present invention, the lower roller does not exist, and the area directly below the transport roller can be exposed, so that image loss does not occur.

<Second Embodiment> FIG. 9 is a block diagram showing a second embodiment of the present invention, and a method for charging the conveying roller will be described below. The configuration and the control system provided for it are the same as those in the first embodiment. In FIG. 9, as the transport roller 34 rotates, friction with the charging material 51 such as rubber that is in contact with the transport roller 34 occurs, electrons move from one of the transport roller 34 and the charging material 51 to the other, and the one to which the electron is applied becomes negative. Those who are charged and lose electrons are positively charged. In this way, static electricity of several KV is generated on the surface of the transport roller 34. As a result, the roller can be charged without applying an electric charge from the outside, so that a power source for charging from the main body is not required and the structure is simplified.

Similar to the first embodiment, when a document is fed and comes into contact with the charged transport roller 34, dielectric polarization occurs, and a charge different from that of the transport roller 34 is generated on the surface of the document, and the transport roller 34 and the document are separated from each other. It is sucked and transported.

<Third Embodiment> FIG. 10 is a block diagram showing a third embodiment of the present invention. Note that the configuration and the control system provided for it are the same as those in the first embodiment described above, and corresponding parts are assigned the same reference numerals and explanations thereof are omitted.

In FIG. 10, if the document detection switch does not turn off after a certain period of time (about 1.5 times the maximum time required for conveyance), the copying machine determines that a document paper jam (JAM) has occurred and the conveyance roller 34. To stop. After that, by applying charges having the same positive and negative electric potentials to the charged transport roller, the adsorbed document is peeled off and the JAM paper can be easily removed from the transport path.

More specifically, after the document JAM is detected, the roller charging brush is applied with positive and negative electric charges by the changeover switch 52 to stop after the charged electric charges of the conveying roller 34 are offset (after one rotation of the conveying roller). As a result, the charge is quickly and surely removed, and the JAM document adsorbed by the transport roller 34 is peeled off from the transport roller 34, and the document is easily removed.

<Fourth Embodiment> FIG. 11 is a diagram showing a fourth embodiment of the document feeder according to the present invention. The following description will be given with respect to the feed rollers when a document sheet is jammed. The configuration and the control system provided for it are the same as in the third embodiment.

In FIG. 11, after the document JAM is detected, the roller charging brush is connected to the GND earth of the frame or the like by the changeover switch 52. As a result, the conveyance roller 34 is made to have the same potential as the frame ground, so that the roller is neutralized, and the original is separated from the roller so that it can be easily taken out. Unlike the means shown in FIG. 10, this means does not need to include a power source having a voltage reverse to the voltage applied to the roller charging brush. Therefore, the configuration can be simplified.

[0042]

As described above, according to the present invention, since the conveying roller is charged and the original is adsorbed and conveyed, only one roller is required, and the structure is simple and inexpensive. Further, since the original conveyed by the antistatic brush is neutralized, the original is not attracted to the original cover or the original table, and the paper jam does not occur, and the operation is good. Further, since there is only one transport roller, the document is not sandwiched between the two rollers as in the conventional technique, and the document in the portion adsorbed by the transport roller can be exposed, so that image loss does not occur.

Further, when the transfer roller is charged by friction with the transfer roller using the charging material, the transfer roller can be charged without the need for an external power source, the structure can be simplified, and the cost can be reduced.

Further, when paper jam occurs, the charge is removed from the conveying roller, and when taking out the paper, the paper does not stick to other parts and can be removed easily and quickly. By applying a voltage opposite to that at the time of charging to the conductive brush at the time of static elimination, the static brush can be eliminated quickly and surely. Further, when removing the charge, if the conductive brush is connected to the ground, no power supply is required, and the structure is simplified accordingly.

[Brief description of drawings]

FIG. 1 is an overall sectional view of a copying machine equipped with a document feeder according to the present invention.

FIG. 2 is an external perspective view of the copying machine shown in FIG.

FIG. 3 is a schematic sectional view showing an embodiment of a document feeder according to the present invention.

FIG. 4 is a schematic cross-sectional view showing a document cover fixing means and a document cover floating means portion of a document conveying apparatus according to the present invention.

5 is an exploded view showing a transport roller of the document transport device shown in FIG.

FIG. 6 is a perspective view of the document feeder shown in FIG.

FIG. 7 is a flowchart illustrating an operation of the document feeder according to the present invention.

FIG. 8 is an operation explanatory view of the document feeder shown in FIG.

FIG. 9 is a configuration diagram showing a second embodiment of a document feeder according to the present invention.

FIG. 10 is a configuration diagram showing a third embodiment of a document feeder according to the present invention.

FIG. 11 is a configuration diagram showing a fourth embodiment of a document feeder according to the present invention.

FIG. 12 is a schematic sectional view showing an example of a conventional document feeder.

[Explanation of symbols]

 1 Copying Machine Main Body 2 Original Plate 3 Original Cover 33 Detection Lever 34 Conveying Roller 41 Charging Brush 42, 43 Static Erasing Brush 44, 45 Peeling Claw

Claims (5)

[Claims] 1. A document conveying device mounted on a device for exposing a document to form an image and reading the image, and a conveying roller for adsorbing and conveying the document by charging, and a roller charging unit for charging the conveying roller. And a document removing unit that removes electric charges from the separated document, and a document removing unit that removes electric charges from the separated document. 2. The original document conveying apparatus according to claim 1, wherein the roller charging means is a means for charging the charging roller by bringing the charging material into contact with a rotating conveying roller. 3. The document feeder according to claim 1, further comprising: a unit for detecting a paper jam of the document, and a roller discharging unit for discharging a charge from the conveying roller when the paper jam of the document is detected. 4. The roller charging means is means for applying a DC voltage to the conductive brush that is in contact with the surface of the conveying roller, and the roller charge eliminating means switches the conductive brush to a DC voltage opposite to that of the roller charging means. 4. The document feeder according to claim 3, which is a means for applying. 5. The roller charging means is means for applying a DC voltage to the conductive brush in contact with the surface of the carrying roller, and the roller discharging means is means for connecting the ground to the conductive brush by switching to the DC voltage. 4. The document feeder according to claim 3, wherein