JP3284870B2 - Paper feeder - 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 a document to a document reading position in a sheet-through type scanner section of a facsimile machine, an electronic copier, a printer, or the like. Hereinafter, a facsimile apparatus will be described as an example for convenience of description.

[0002]

2. Description of the Related Art For example, in a scanner section of a facsimile apparatus, originals are fed one by one to an image sensor provided at an original reading position by a paper feeding device, and an image of the original is read by the image sensor and then read. The signal of the image is transmitted to the other party, and it is required to accurately feed the document one by one to the image sensor in order to accurately read the image of the document.

Conventionally, as shown in FIG. 5, an arc-shaped portion of a fan-shaped paper feed roller 50 and a sabaki member 51 provide a document 24 on a document table (not shown).
0 is fed one by one to the image sensor 52, and the registration sensor 53 detects the leading edge of the document 240 and the reading start position (timing) in the image sensor 52.
Set. A pair of transport rollers 54, 54 are provided between the paper feed roller 50 and the image sensor 52,
By the driving force of the driving mechanism, the transport rollers 54, 54 pinch the original 240 so that the image sensor 52 and the reading roller 5
5, the document is conveyed at a predetermined speed to stabilize the document conveying properties such as straightness and constant speed.

[0004]

However, in the above-described conventional paper feeder, a pair of transport rollers 5 for transporting the original 240 are used.
4 and 54 and the drive mechanism therefor, the number of parts increases and the apparatus becomes expensive, and all of the paper feed roller 50, the transport roller 54, and the reading roller 55
Since the motor is rotated by two motors, a motor having a large torque is required.
There is a problem that it is difficult to reduce the size of the apparatus because the distance L2 between them is long.

Therefore, the friction coefficient of the sabaki member is increased,
A method has been proposed in which a document sent out from a paper feed roller is directly fed between an image sensor and a reading roller, and a pair of transport rollers is omitted. Here, the reading roller is disposed in contact with the image sensor. The reading roller presses a document sandwiched between the image sensor and the image sensor to read a document image. The read document is transported downstream in the transport direction.

However, in this method, since the speed at which the document is conveyed by the paper feed roller is not stable, the time required for the document to pass through the registration sensor and reach the image sensor (see FIG. 5A) varies, and the reading is performed. There is a problem that the start position varies easily. When the paper feed roller is formed in a perfect circular shape, the paper feed roller becomes a rotation load of the reading roller, and the problem of uneven feeding may still be a concern.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a compact and inexpensive paper feeder capable of stably transporting an original without causing uneven feeding.

[0008]

SUMMARY OF THE INVENTION Accordingly, a paper feeder according to the present invention is a paper feeder which feeds documents one by one to a document reading position.
And a fan-shaped paper feed roller for rotatingly driving and sending out the original when the arc-shaped portion comes into contact with the original, and a sheet feeder for feeding the original one by one together with the paper feed roller. A member and a transport roller that is disposed so as to be able to come into contact with the arc portion of the paper feed roller on the downstream side in the transport direction of the paper feed roller, and that sandwiches and transports the original together with the arc portion of the rotating paper feed roller; At the downstream side in the transport direction of the transport rollers, the document is arranged at a document reading position within a distance equal to the length of the arc-shaped portion of the paper feed roller from the transport rollers, and the document transported from the paper feed rollers and the transport rollers And a reading roller for transporting the sheet to the downstream side in the transport direction.

A feature of the present invention is that a transport roller is provided on the downstream side in the transport direction of the paper feed roller, the roller is brought into contact with an arc-shaped portion of the paper feed roller, and a document to be fed is sandwiched between the two. The point is that the sheet is stably conveyed at a predetermined speed toward the reading position. It is important that the document reading position is set at a position within a distance equal to the length of the arc-shaped portion of the paper feed roller from the transport roller on the downstream side in the transport direction of the transport roller. Thus, the document conveyed by the sheet feeding roller and the conveying roller can be reliably taken into the reading roller. However, even after the document is taken in by the reading roller, if the document is held between the arc-shaped portion of the paper feed roller and the transport roller, the document may be produced due to a manufacturing error of the rotation speed or the transport force, an individual difference, or the like. An extra load is applied to the document, which may cause uneven feeding. Therefore, it is preferable that the reading roller is disposed at a distance from the transport roller that is substantially equal to the length of the arc-shaped portion of the sheet feeding roller.

In addition, a pair of feed rollers are provided at the downstream side of the document reading position in the transport direction instead of the reading roller, and are driven to rotate, so that the document transported by the paper feed roller and the transport roller is transported to the downstream side in the transport direction. You can send it out. However,
The pair of feed rollers 218 is arranged at a position within a distance equal to the length of the arc-shaped portion of the feed roller from the transport roller 216.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to specific examples shown in the drawings. 1 to 3 show a preferred embodiment of the present invention. In FIG. 1, a facsimile apparatus includes a scanner unit 20 for reading and transmitting an image of a document 240 and a printer unit 3 for printing out a received image.
0 and a transmitting / receiving unit (not shown) for transmitting and receiving image signals. In this example, the scanner section 20 is laid out at the rear of the housing 11, and the printer section 30 is laid out at the front of the housing 11, but other layouts are possible. Since the printer unit 30 and the transmission / reception unit are not directly related to the present invention, a detailed description thereof will be omitted.
A conventionally known structure can be adopted.

In the scanner section 20, the housing 11
A document placing table 200 is attached to the rear end wall surface so as to be continuous with a push-up plate 201 inside the housing 11, and the push-up plate 201 is urged by a spring and lifted upward to push up the original 240.

In front of the push-up plate 201, the paper feed roller 20
2 are arranged. As shown in FIG. 2, the paper feed roller 202 has a sector shape including an arc portion 202 a having a predetermined circumference and a non-arc portion 202 b, and
As shown in FIG.
4 is mounted almost at the center. A drive gear 205 is attached to one end of the shaft 204, and the drive gear 205 is connected to a rotation shaft of a drive motor 235 via a plurality of reduction gears. The paper feed roller 202 is driven to rotate by the drive motor 235. The original 240 is sent forward by contact between the arc-shaped portion 202a and the original 240 on the original placing table 200.

Below the paper feed roller 202, a sabaki member 2 is provided.
03 is arranged. The sabaki member 203 is urged upward by a coil spring 217 so as to be able to come into contact with the arcuate portion 202a of the rotating paper feed roller 202.
02 and the originals 240 on the original placing table 200 are fed one by one.

An image sensor 206 is provided in front of the paper feed roller 202 so as to extend in the width direction of the housing 11, and a reading roller 20 is provided below the image sensor 206.
7 is provided in contact with the reading glass surface of the image sensor 206. As shown in FIG. 3, the reading roller 207 has a length approximately one third of that of the image sensor 206, and is attached to the center of the shaft 208. A drive gear 209 is attached to one end of the shaft 208.
Is connected to the rotation shaft of the drive motor 235 via a reduction gear. The reading roller 207 is rotationally driven by the driving motor 235 and sends out the original 240 sent between the reading roller 207 and the glass surface of the image sensor 206 forward.

Image sensor 206 and paper feed roller 202
The registration sensor 210 is disposed between the two as shown in FIGS. The registration sensor 210 is shown in FIG.
As shown in (2), the leading edge of the original 240 fed from the paper feed roller 202 abuts and is kicked. This is detected by the photomicroswitch 212 and the reading start position of the original 240 in the image sensor 206 is set.

Also, from the front of the push-up plate 201, a paper feed roller 202, an image sensor 206 and a reading roller 207.
The upper and lower guide members 21
3 is provided, and the guide member 213 is connected to the image sensor 20.
6 from the lower front. Guide member 21
A document discharge roller 214 is disposed at the lower end of the document feeder 3, and sends out the document 240 that has been read by the image sensor 206 to a document discharge tray 215 at the rear.

In this embodiment, the paper feed roller 202
A transport roller 216 is provided in front of (the downstream side in the document transport direction). The transport roller 216 is an arc-shaped portion 202a of the paper feed roller 202 which rotates as shown in FIGS.
The document 240 is driven to rotate in contact with the document, and is conveyed toward the reading roller 207 from the document 240 sent from the sheet feeding roller 202. Although the transport roller may be driven synchronously with the paper feed roller, it is preferable to rotate the transport roller following the paper feed roller from the viewpoint of simplifying the structure of the apparatus.

The reading roller 207 is provided with a conveying roller 216.
Is set to a position at a distance substantially equal to the circumference of the arc-shaped portion 202a of the sheet feeding roller 202 from the sheet feeding roller 202. The document 240 conveyed by the arc-shaped portion 202a and the conveyance roller 216 between the time when the conveyance roller 216 starts to contact the arc-shaped portion 202a of the paper feed roller 202 and the time when the conveyance roller 216 comes to the position of the non-arc-shaped portion 202b. Of the image sensor 206
And the reading roller 207.

Next, the operation will be described.
When the start button for reading a document is pressed, the push-up plate 201 is lifted upward so that the leading end of the document 240 is moved upward. The feed roller 202 is brought into contact with the arc-shaped portion 202a.

On the other hand, when the start button for reading the original is pressed, the drive motor 235 is driven,
2 and the reading roller 207 are driven to rotate, and the original 240 contacts the arc-shaped portion 202 a of the paper feeding roller 202.
Are fed forward one by one by the action of the sabaki member 203. When the leading edge of the document 240 reaches the position of the registration sensor 210 and kicks the registration sensor 210, the reading start position of the image sensor 206 is set. Further, when the leading end of the document 240 reaches between the reading roller 207 and the image sensor 206, the reading of the image of the document 240 is started while the document 240 is taken in between them and conveyed forward.

At this time, the original 240 sent from the paper feed roller 202 is sandwiched between the arc-shaped portion 202a of the paper feed roller 202 and the transport roller 216 with the rotation of the paper feed roller 202, and Arc-shaped portion 20 of 202
It is transported forward by 2a and the transport roller 216. Therefore, the document 240 is stably and accurately conveyed at a predetermined speed.

Further, when the original 240 is taken in between the reading roller 207 and the image sensor 206 and is conveyed forward by the reading roller 207, the conveying roller 216 is moved to the non-circular portion of the sheet feeding roller 202. 202b
And the paper feed roller 202 and the original 240 are in a non-contact state. Accordingly, the feed roller 202 is
7 and no irregularity in the feeding of the document 240
It is possible to perform accurate document reading. In the case of such a sheet feeding device, when the document is located on the trailing end side, the document is supported by the sheet feeding roller and the transport roller, and the relative position between the image sensor and the document may change and the reading accuracy may be reduced. An appropriate document supporting member, for example, one or a plurality of rollers may be provided between the transport roller and the paper feed roller.

FIG. 4 shows a second embodiment of the present invention, in which the same reference numerals as those in FIG. 2 denote the same or corresponding parts. In this example, a leaf spring 219 is used to bias the push-up plate 201, and a pair of feed rollers 218, 218 are provided downstream of the image sensor 206 in the transport direction instead of the reading roller 207, and are driven to rotate by a drive motor 235. , Paper feed roller 2
02 and the original 2 conveyed by the conveying roller 216
40 is sent to the downstream side in the transport direction. However, it goes without saying that the pair of feed rollers 218 is arranged at a position within a distance equal to the length of the arc-shaped portion of the paper feed roller from the transport roller 216.

[0025]

According to the present invention, the pair of transport rollers between the paper feed roller and the image sensor is omitted as compared with the conventional one, so that the distance L1 between the paper feed roller and the image sensor (see FIG. 2) (L1 <L2), and the apparatus can be made compact.

Further, since a pair of transport rollers and a drive mechanism thereof are not required, the number of parts can be reduced, and a motor having a small torque is required for driving the driven system of the sheet feeding device, and the motor current can be reduced. Therefore, the power supply may be small, and the cost of the apparatus can be significantly reduced.

Further, since the original fed from the paper feed roller is conveyed toward the image sensor by the arc-shaped portion of the paper feed roller and the conveyance roller, the above-described apparatus has advantages of reduction in size and cost. Without compromising
The document can be stably conveyed toward the image sensor at a predetermined speed. As a result, the document can be transported accurately between the registration sensor and the image sensor (see FIG. 2A), and the reading accuracy of the document can be guaranteed.

Further, since the original is conveyed using the arc-shaped portion of the paper feed roller, the original is sandwiched between the conveyance roller and the paper feed roller in a portion other than the arc-shaped portion of the paper feed roller. The feed roller and the feed roller only support the lower part of the document, so that the feed roller and the feed roller do not load the reading roller or the pair of feed rollers in front of the image sensor, thereby reducing the occurrence of uneven document feed. Prevention can be surely performed and accurate document reading can be performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a facsimile apparatus including a sheet feeding device according to a first embodiment of the present invention.

FIG. 2 is an enlarged view showing a main part of the sheet feeding device of FIG.

FIG. 3 is a bottom view illustrating a relationship among a sheet feeding roller, a conveying roller, a registration sensor, an image sensor, and a reading roller in the sheet feeding device of FIG. 1;

FIG. 4 is an enlarged view of a main part showing a sheet feeding device according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating a conventional sheet feeding device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 20 scanner unit 202 paper feed roller 202 a arc-shaped portion 202 b non-arc-shaped portion 203 sabaki member 206 image sensor 207 reading roller 216 transport roller 218 feed roller 240 original

Claims (2)

(57) [Claims] In a paper feeder configured to feed a document one by one to a document reading position, the document is disposed at a position distant from the document reading position, and is driven to rotate so that the arc-shaped portion and the document are moved . A fan-shaped paper feed roller for sending out a document by contact; a sabaki member for feeding the document one by one together with the paper feed roller; A transport roller that is disposed so as to be in contact with the arc-shaped portion and that pinches and transports the document together with the arc-shaped portion of the rotating paper feed roller; A reading roller disposed at a document reading position within a distance equal to the length of the arc-shaped portion of the roller and transporting the document transported from the paper feed roller and the transport roller to the downstream side in the transport direction. Paper feeder . 2. A sheet feeding apparatus which feeds documents one by one to a reading position of a document. The feeding device is disposed at a position distant from the document reading position, and is driven to rotate so that the arc-shaped portion and the document are moved . A fan-shaped paper feed roller for sending out a document by contact; a sabaki member for feeding the document one by one together with the paper feed roller; A transport roller disposed so as to be in contact with the arc-shaped portion and nipping and transporting the original together with the arc-shaped portion of the rotating paper feed roller; and a transport roller from the transport roller downstream of the original reading position in the transport direction. And a pair of feed rollers, which are arranged at positions within a distance equal to the length of the arc-shaped portion of, and sandwich the document conveyed from the paper feed roller and the conveyance roller and feed the document to the downstream side in the conveyance direction. Feature Paper equipment.