JP3544049B2 - Document feeder - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet-through type document copying apparatus in which a document reading unit is fixed and an image is read by performing exposure while moving a document, and particularly for sequentially feeding documents one by one to the document reading unit. And a document feeder.
[0002]
[Prior art]
Conventionally, a document feeder of this type is provided with a document lifting member for bringing the documents stacked in the storage means into contact with a paper feeding belt, and raising the document lifting member during paper feeding to feed the document to the paper feeding belt. There is a sheet that comes in contact with the sheet and feeds the sheet. Japanese Patent Application Laid-Open No. 4-350033 discloses that a sheet material laminated on a sheet material laminate is separated and fed one by one by a separating and feeding means including a feeding member and a separating member contacted at a predetermined pressure. In a feeding device for transporting the separated and fed sheet material by transporting means downstream of the separating and feeding means in a sheet material feeding direction, the contact pressure of the separating and feeding means is released after the sheet material is transported, and the sheet is released. A material in which back tension is not applied to the material is disclosed.
[0003]
[Problems to be solved by the invention]
In the method in which the document lifting member is lifted up and brought into contact with the paper feed belt to feed the paper, friction occurs between the paper feeding belt and the document lifting member after the rear end of the final document has passed through the feeding means. There has been a problem that the life of the portion where the sheet feeding belt and the document lifting member contact each other is shortened. Therefore, the present invention solves the above-described problem by lowering the document lifting member when the trailing end of the final document has passed the sending means, and improves the life of the contact portion between the sheet feeding belt and the document lifting member. Aim.
[0004]
[0005]
[0006]
[0007]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a document feeder according to claim 1, wherein a document reading unit is fixed, and a plurality of documents are provided in a sheet-through type document copying apparatus which reads an image by performing exposure while moving the document. Storing means for storing documents stacked in a stack, a document lifting member for abutting a document stored in the storing means on a paper feed belt, and a document stored in the storing means connected to the storing means. A feeding means for sequentially feeding the document, and a conveying means having one end connected to the feeding means and discharging the document sent from the sending means to a document discharge section through an image reading section; To cause the originals in the storage means to be sequentially sent out, and when the rear end of the last original in the storage means has passed through the sending means, lower the original lifting member. It is characterized in.
[0008]
[0009]
[0010]
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic side view of an embodiment of a document feeder according to the present invention. The leading end of the document 2 set on the document loading table 1 is brought into contact with a paper feed belt 4 by a bottom plate 3 raised by a solenoid (not shown). While the bottom plate 3 is in contact with the paper feed belt 4, the original 2 is sequentially fed one by one by the paper feed belt 4 and the separation roller 5. A paper feed detection sensor 6 is provided downstream of the paper feed belt 4. The paper feed detection sensor 6 detects that the document 2 has passed the paper feed unit. The document 2 that has passed through the paper feeding unit passes through the transport roller 7 and an image is read by the image reading unit 8. The document 2 that has passed through the image reading unit 8 is discharged onto a tray 11 from a discharge roller 9.
[0012]
A registration sensor 10 is provided between the transport roller 7 and the image reading unit 8. The registration sensor 10 detects passage of the leading end and the trailing end of the conveyed document 2. When the passage of the leading edge and the trailing edge of the document are detected, the registration sensor 10 outputs a detection signal, and calculates the amount of advance of the document from this position by counting the number of pulses of a stepping motor as a roller driving source. The timing at which the leading and trailing edges of the document arrive at the image reading unit 8 is calculated.
[0013]
In the above configuration, the bottom plate 3 operates based on a detection signal from the sheet feed detection sensor 6 or the registration sensor 10 and moves up or down. That is, a detection signal from the paper feed detection sensor 6 or the registration sensor 10 is sent to a control unit (not shown), and the control unit outputs a command to move up or down to a solenoid that operates the bottom plate 3.
[0014]
Hereinafter, some aspects of the operation timing will be described. In FIG. 2, when a feed start signal is transmitted from the copying machine, the solenoid is driven to move up the bottom plate 3, and the originals 2 on the original mounting table 1 are fed by the feed belt 4 one by one. You. Until the last document on the document loading table 1 is conveyed, the bottom plate 3 remains in the raised state. When the trailing end of the final document 2a passes through the paper feed sensor 6, the paper feed detection sensor 6 detects this and outputs a detection signal to the control unit. The control unit that has received the detection signal issues a command to drive the solenoid downward, and based on this, the bottom plate 3 descends. After all the originals on the original mounting table 1 have been conveyed in this way, the bottom plate 3 is separated from the feed belt 4. As a result, the bottom plate 3 and the paper feed belt 4 do not come into direct contact with each other, and the problem of shortening of the service life due to the friction can be prevented.
[0015]
For reference, FIG. 3 shows an embodiment at another timing of lifting and lowering the bottom plate 3. As in the above-described embodiment, when a paper feed start signal is transmitted from the copying machine, the solenoid is driven to move up the bottom plate 3, and the originals 2 on the original mounting table 1 are fed one by one by the feed belt 4. Paper is fed. Until the last document on the document loading table 1 is conveyed, the bottom plate 3 remains in the raised state. When the trailing end of the final document 2a passes through the image reading section 8, the registration sensor 10 detects this and outputs a detection signal to the control section. The control unit that has received the detection signal issues a command to drive the solenoid downward, and based on this, the bottom plate 3 descends. When the solenoid is operated while reading the image of the final document 2a as in the above embodiment, the load on the drive system is reduced, and image jitter is more likely to occur. In the present embodiment, since the solenoid is driven after reading the image, such a problem is avoided.
[0016]
For reference, FIGS. 4 and 5 show an embodiment at another timing of lifting and lowering the bottom plate 3. The bottom plate 3 is raised by a feed start signal from the copying machine, and one original 2 is fed. When the leading end of the fed document 2 passes through the paper feed sensor 6, a detection signal is sent to the control unit, and the solenoid is driven to lower the bottom plate 3 (see FIG. 4). As a result, the back tension between the bottom plate 3 and the feed belt 4 applied to the original 2 is released, and the original 2 is smoothly transported by the feed belt 4 and the transport roller 7. Next, when the rear end of the document 2 passes through the paper feed sensor 6, a detection signal is sent from the paper feed sensor 6 to the control unit to drive the solenoid, and the bottom plate 3 rises again (see FIG. 5). As a result, the next document can be fed. When the next original does not exist, the last original is read by the image reading unit 8 and discharged to the tray 11 while the bottom plate 3 is lowered.
[0017]
For reference, FIGS. 6 and 7 show an embodiment at another timing of lifting and lowering the bottom plate 3. The bottom plate 3 is raised by a feed start signal from the copying machine, and one original 2 is fed. When the leading edge of the fed document 2 passes through the paper feed sensor 6, the paper feed sensor 6 detects this and outputs a detection signal to the control unit (see FIG. 6). The control unit drives the solenoid based on the detection signal to lower the bottom plate 3. As a result, the back tension between the bottom plate 3 and the feed belt 4 applied to the original 2 is released, and the original 2 is smoothly transported by the feed belt 4 and the transport roller 7. Next, when the rear end of the document 2 passes through the image reading unit 8, a detection signal is sent from the registration sensor 10 to the control unit to drive the solenoid, and the bottom plate 3 is raised again (see FIG. 7). As a result, the next document can be fed. If there is no next original, the last original is discharged while the bottom plate 3 is lowered. At the above timing, since the bottom plate 3 is raised after the reading of the document 2 is completed, there is no load fluctuation of the driving system during reading of the document, and no vibration occurs due to the rise of the bottom plate. Can be prevented. In the above configuration, since the interval between paper feeds is wider than in the above-described embodiment, the number of documents that can be fed within a certain time is reduced. However, this can be solved by a method such as increasing the driving speed between the end of reading the image of the original 2 and the start of reading the next original.
[0018]
【The invention's effect】
As described above, the document feeder according to claim 1 lowers the document lifting member when the rear end of the final document has passed the feeding means, so that the life of the contact portion between the paper feeding belt and the document lifting member is reduced. There is an effect that can be improved.
[0019]
[0020]
[0021]
[Brief description of the drawings]
FIG. 1 is a schematic side view of an embodiment of a document feeder according to the present invention.
FIG. 2 is a side view showing the timing of lifting and lowering of a document lifting member.
FIG. 3 is a side view showing an embodiment at another timing of lifting and lowering of a document lifting member.
FIG. 4 is a side view showing the embodiment at another timing of lifting and lowering of the document lifting member.
FIG. 5 is a side view showing an operation subsequent to the operation in FIG. 4;
FIG. 6 is a side view showing the embodiment at another timing of lifting and lowering of the document lifting member.
FIG. 7 is a side view showing an operation subsequent to the operation in FIG. 6;
[Explanation of symbols]
REFERENCE SIGNS LIST 1 document loading table 2 document 3 bottom plate 4 feed belt 5 separation roller 6 feed detection sensor 7 transport roller 8 image reading unit 9 discharge roller 10 registration sensor

Claims (1)

In a sheet-through type document copying apparatus in which a document reading unit is fixed and an image is read by performing exposure while moving the document, a storage unit that stores a plurality of documents in a stacked state, and a storage unit that is stored in the storage unit. A document lifting member for bringing the original into contact with the paper feed belt, a delivery unit connected to the storage unit and sequentially delivering the stored document from the storage unit, and an end connected to the delivery unit and connected to the delivery unit. Transport means for discharging the original sent from the means to the original discharge section through the image reading section, raising the original lifting member at the start of feeding of the original to sequentially send the originals in the storage means, and A document feeder for lowering the document lifting member when the trailing end of the last document in the means has passed through the sending means;

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