JPH07319229A - Document feeder and image reader provided with the same - Google Patents

Abstract

PURPOSE:To miniaturize the device by providing a document attracting means for separating a document abutting on a platen glass on a document feeding means. CONSTITUTION:The document feeding means 1 is disposed so as to come into contact with the upper surface of the left end of the platen glass 52 and the document P fed from a separation part one by one is attracted and fed by the document attracting means provided on the feeding means 1 and guided to a space (specified position or reading position) between the feeding means 1 and the platen glass 52. Thereafter, the document P is separated from the platen glass 52 in the state where it is attracted by the feeding means 1. The leading edge of the document P is separated from the feeding means 1 and guided to a feeding roller pair 40 by the action of a separation pawl 21, and ejected on a document receiving table provided on the upper surface of a left document plate 41. Therefore, a platen glass only used for rough reading is disused, and a device main body is made small in size and constituted so that its production cost is restrained to be low.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document feeding device and an image reading device equipped with this device, and more particularly, for example, a copying machine or a laser beam printer having a device for feeding a document to a predetermined position such as a document reading portion. The present invention relates to a document feeding device used in the image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, various image reading apparatuses having a document flow reading mode have been proposed.

FIG. 8 is a schematic cross-sectional view of an essential part showing an example of an image reading apparatus 50 provided with a document feeding device 30 having a relatively simple structure having a document flow reading mode.

Reference numeral 51 is a small platen glass used in the original flow reading mode, and reference numeral 52 is a large platen glass used when the original is manually placed and fixed and scanned by the reading optical system.

The document feeder 30 has a document tray 31, and the document P is set with the image surface facing upward.

Adjacent to the document tray 31, a half-moon shaped feed roller 32 and a stopper 33 that moves up and down by a stopper solenoid (not shown) are arranged. The document P is restricted by the protruding stopper 33 so that it cannot move downstream.

When the operating condition is input and the start key (not shown) is pressed on the operation section of the image reading device 50, the stopper 33 sinks to open the path of the original P, and the original P is fed by the feed roller. Received 32 feeds and advanced to the downstream area.

At the downstream side of the stopper 33, there is provided a separating section composed of a conveying roller 34 and a separating belt 35 which constitute a separating section, and each of them is rotated in the direction of the arrow and is advanced from the original tray 31. P is separated sheet by sheet and conveyed further downstream.

The carrying roller 36 is arranged so as to contact the upper surface of the small platen glass 51, and the carrying roller 36 is provided.
The pinch rollers 37 and 38 are in contact with the peripheral surface of the.

Documents P conveyed one by one from the separating section
Is guided between the transport roller 36 and the platen glass 51 by the action of the transport roller 36 and the pinch rollers 37 and 38. Thereafter, the document P is separated from the platen glass 51 by the scooping member 39 and guided to the pair of conveying rollers 40, and the document receiving table 42 provided on the upper surface of the document pressure plate 41.
Is discharged on.

While the document P is being conveyed on the small platen glass 51, the first mirror table 53 is placed on the small platen glass 5.
It is fixed at a position just below 1. The first mirror table 53 includes a document illumination lamp 54, reflecting shades 55a, 55b, 55c and a first mirror 56. 57 is the second
It is a mirror base and is composed of a second mirror 58 and a third mirror 59. The original P conveyed on the upper surface of the small platen glass 51 is the original illumination lamp 54 and the reflection shades 55a, 5
Illuminated by 5b and 55c, the image is guided by the first mirror 56, the second mirror 57, and the third mirror 58, reduced in size by the reader lens 60, and read by the CCD line sensor 61 arranged on the image plane. To be

[0012]

However, in the above-mentioned conventional example, since the small platen glass dedicated to the original flow reading and the ordinary large platen glass for fixed original reading are arranged separately from each other, the following problem occurs. There was a flaw.

(1) The main body of the apparatus becomes large.

Compared to a device that only reads a document while fixing it, the space required for the original document reading surely increases the size of the device.

(2) The manufacturing cost is increased.

The need for a dedicated small platen glass and the increase in size of the above-mentioned apparatus increase the manufacturing cost.

[0017]

According to the present invention, the document is separated from the contact with the platen glass by the document conveying means for guiding the document onto the platen glass and scanning the image, for example. A document suction means for
Alternatively, by making the part for the original document scanning reading part of the platen glass prepared for fixed document reading, the platen glass dedicated for the scanning document is abolished, and the size of the main body of the device is reduced, The structure has a low manufacturing cost.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment of the present invention and is a schematic sectional view of an essential part of an image reading device 50 having a document feeding device 30.

Reference numeral 52 indicates that the document is manually placed and fixed,
It is a platen glass that is commonly used in two cases, one for scanning with the reading optical system and the other for feeding the original with the original feeding device 30 and fixing the reading optical system.

The document feeder 30 has a document tray 31, and the document P is set with the image side facing upward.

Adjacent to the original tray 31, a half-moon shaped feeding roller 32 and a stopper solenoid (not shown)
A stopper 33 that moves up and down is provided, and the original P when set on the original tray 31 is restricted by the protruding stopper 33 so that it cannot advance downstream.

When an operating condition is input and a start key (not shown) is pressed on the operation section of the device 50, the stopper 3 is pressed.
3 is depressed and the path of the document P is released, and the document P is fed by the paper feed roller 32 and advances to the downstream portion.

At the downstream portion of the stopper 33, there is disposed a separating portion composed of a conveying roller 34 and a separating belt 35 which constitute a separating portion, and each of them is rotated in the direction of the arrow and advanced from the original tray 31. P is separated sheet by sheet and conveyed further downstream.

The original conveying means 1 is disposed so as to contact the upper surface of the left end portion of the platen glass 52, and the originals P conveyed one by one from the separating portion are transferred to the original conveying means 1 as described later. By the provided document suction means, it is sucked and transported by the document transport means 1 and guided between the document transport means 1 and the platen glass 52 (a predetermined position or a reading position). After that, the original P is separated from the platen glass 52 while being attracted to the original conveying means 1. The leading edge of the original P is separated from the original conveying means 1 by the action of the separation claw 21, is guided to the conveying roller pair 40, and is discharged onto the original receiving tray 42 provided on the upper surface of the original pressing plate 41.

While the document P is being transported on the platen glass 52, the first mirror table 53 is fixed immediately below the document transporting means 1. The first mirror table 53 is the original illumination lamp 5
4. The reflection shades 55a, 55b, 55c and the first mirror 56.

The original P conveyed by the original conveying means 1 on the upper surface of the left end portion of the platen glass 52 is illuminated by the original illumination lamp 54 and the reflection shades 55a, 55b, 55c, and the image thereof is the first mirror 56, the second mirror. 57, third
The light is guided by the mirror 58, reduced in image by the reader lens 60, and read by the CCD line sensor 61 arranged on the image plane. The read image is converted into an electric signal by the image processing unit and transmitted to the laser modulation (laser scanner) of the image forming apparatus, and the image is formed on the copy paper based on this.

FIG. 2 is a cross-sectional view of an essential part showing the structure of the document conveying means 1. Reference numeral 2 is a hollow cylindrical drum, and a large number of ventilation holes 3 are regularly formed in the peripheral surface.

FIG. 3 is a schematic view showing the longitudinal structure of the document conveying means 1. One end of the cylindrical drum 2 is closed and the other end is connected to an axial fan 5 via a suction duct 4.

In order for the document conveying means 1 to suck and convey the document P, the axial fan 5 is rotated to generate a negative pressure inside the cylindrical drum 2 and the negative pressure is provided on the peripheral surface of the cylindrical drum 2. The document P is sucked and conveyed by the innumerable holes 3.

The case where the original P is set on the original tray 31 and the image is read by the flow reading has been described above. Next, the original P is read by the platen glass 52 with reference to FIG.
The case where the optical system is scanned and read by manually setting in the following will be described.

The document feeding device 30 and the document pressure plate 41 can be integrally opened and closed with respect to the image reading device main body 50.
The document P is abutted against the document positioning member 62 and set on the platen glass 52 (predetermined position or reading position).

Document illumination lamp 54 and reflectors 55a, 55
b, 55c and the first mirror 56, that is, the first mirror base 5
3 is driven rightward along the lower surface of the platen glass 52 at a speed of V, and the second mirror 58 and the third mirror 59, that is, the second mirror base 57 is driven at a speed of v / 2 in the wind direction.
The document P is scanned from the left end to the right end and read by the reader lens 60 and the CCD line sensor 61.

Next, the structure of the image forming apparatus main body will be described with reference to FIG. The reading device 50 (including the document feeding device 30) is also referred to as an image forming device.

100 is an upper cassette, and the sheets in the cassette are separated and fed one by one by the action of the separating claw and the feeding roller 101 and guided to the registration rollers 106. 1
Reference numeral 02 denotes a lower cassette, and the sheets in the cassette are separated and fed one by one by the action of the separating claw and the feeding roller 103 and guided to the registration roller 106.

Reference numeral 112 is a photosensitive drum, 114 is a developing device, and 1
A transfer charger 15 and a separation charger 116 form an image forming unit.

Reference numeral 117 is a conveyor belt for conveying the image-formed sheet material, and 118 is a fixing device. The sheet is guided to a discharge roller 121 and conveyed to a discharge tray 123.

An image is formed on the photosensitive drum in accordance with the set number of copies for one original placed on the platen, and a sheet material corresponding to the number of copies is set in the cassette 10.
The image is fed from 0 or 102 each time an image is formed on the photosensitive drum. The registration between the image on the photosensitive drum and the sheet material is performed by the registration roller 106.

When the required number of copies are formed, the original is ejected from the platen, and the next original is positioned on the platen. The same applies hereinafter.

(Other Embodiments) FIG. 6 shows a second embodiment of the present invention and is a schematic sectional view of an essential part of an image reading apparatus 50 having a document feeding apparatus 30 as in the first embodiment. Since the basic structure is the same as that of the first embodiment, the same reference numerals are given and the description thereof is omitted. In this embodiment, another suction means is provided.

Reference numeral 11 is a document conveying means, and 14 is a charging roller.

FIG. 7A is a cross-sectional view of the essential parts showing the configurations of the document conveying means 11 and the charging roller 14. Reference numeral 13 is a cylindrical roller made of a material such as rubber having appropriate elasticity, and 12 is a dielectric tube made of resin or the like having a strong charging property. The charging roller 14 is biased by a charging power source (voltage is applied), contacts the dielectric tube 12, and is driven to rotate. The dielectric tube 12 repeats contact and peeling with the charging roller 14 to accumulate electrostatic charges.

1 by the conveying roller 34 and the separation belt 35
The originals P conveyed one by one are attracted and conveyed by the electrostatic attraction force of the dielectric tube 14, and are guided between the original conveying means 11 and the platen glass 52. The original P is separated from the platen glass 52 while being attracted to the original conveying means 11. The leading edge of the original P is separated from the original conveying means 11 by the action of the separation claw 21 and guided to the conveying roller pair 40, and the original receiving tray 42 provided on the upper surface of the original pressing plate 41.
Is discharged on.

In addition to the above, the charging means may be means by corona discharge as shown in FIG. 7 (b). It is made of a single corona wire surrounded by a grounded metal shield.

As described above, in the document feeding apparatus, the document feeding means for guiding the document onto the platen glass and scanning the image is used for separating the document from the contact with the platen glass. The provision of the suction means has the following effects.

(1) Miniaturization of device Since the space required only for the original flow reading can be shared with the space for fixed original reading, not only the image forming apparatus main body but also the original feeding device can be miniaturized. be able to.

(2) Reduction in manufacturing cost The platen glass dedicated to the flow-read is unnecessary, and the pinch rollers and the conveyance guide plate are unnecessary as compared with the ordinary conveying system using the document feed rollers. Together with the miniaturization, the configuration can be simplified and the manufacturing cost can be reduced.

[0047]

Since the document feeding apparatus according to the present invention is constructed as described above, there is an effect that the apparatus can be downsized.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an essential part of a first embodiment of the present invention.

FIG. 2 is a sectional view of a main portion of the first embodiment.

FIG. 3 is a schematic longitudinal view of the first embodiment.

FIG. 4 is an operation explanatory diagram in the first embodiment.

FIG. 5 is a schematic cross-sectional view showing the configuration of the image forming apparatus.

FIG. 6 is a schematic cross-sectional view of an essential part of a second embodiment implementing the present invention.

FIG. 7 is a cross-sectional view of the essential parts of the second embodiment.

FIG. 8 is a schematic sectional view of a main part of a conventional example.

[Explanation of symbols]

 1, 11 Document Feeding Means 2 Cylindrical Drum 3 Vent 4 Suction Duct 5 Axial Fan 12 Dielectric Tube 14 Charging Roller

Claims (5)

[Claims] 1. An image reading apparatus having an original flow reading mode in which an image reading means is fixed at an arbitrary position and an image of a conveyed original is read during conveyance of the original, and the original is guided onto a platen glass to flow the image. An image reading apparatus characterized in that a document conveying means for reading is provided, and the document conveying means is provided with a document adsorbing means for separating the document from contact with the platen glass. 2. The image reading apparatus according to claim 1, wherein the document conveying means is composed of an air suction type drum, and negative pressure by air suction is used as the document suctioning means. 3. The image reading apparatus according to claim 1, wherein the document conveying means is composed of a charging roller and the electrostatic attraction force is used as the document attracting means. 4. An image forming apparatus using the image reading apparatus according to any one of claims 1 to 3. 5. An original conveying means for guiding and conveying an original to a predetermined position is provided, and the original conveying means is provided with an original suction means for separating the original from contact with the predetermined position. Document feeder.