JPH10279128A - Original conveying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an original conveying device, which precisely detects the original jamming based on the quantity of the original being conveyed and which, when the original jamming occurs, stops the conveyance of the original quickly in order to avoid the breakage of the original in a device such as a copier or facsimile equipment. SOLUTION: An original conveying device 1 is provided with original-size detecting means 14, 15, which detect the size of an original, an original quantity detecting means, which detects the quantity of the original being conveyed by an original conveying means 13, and an original jamming detecting means, which detects the original jamming, based on both the length of the original that is detected by the original-size detecting means 14, 15 and the quantity detected by the original quantity detecting means on the original being conveyed. With this contrivance, the original jamming can be detected based on the quantity of the original being conveyed, and, if the original jamming occurs, the conveyance of the original can quickly be stopped so as to prevent the breakage of the original.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document feeder, and more particularly to detection of a paper jam in a copying machine or the like.

[0002]

2. Description of the Related Art Conventionally, copiers and facsimile machines have
In order to automatically copy and transmit a document by setting a plurality of documents, a document feeder that feeds and discharges a document and transports the document is used. The document conveying device includes, for example, a sheet feeding unit, a conveying unit, a sheet discharging unit, a contact glass, and the like, conveys a document fed from the sheet feeding unit to a predetermined position on the contact glass surface, And discharge the paper.

On the other hand, these document feeders automatically feed and discharge paper. However, paper jams may occur in the paper feeding means and paper discharging means. As a method for detecting this paper jam, there is a paper jam detection method described in JP-A-61-81345. FIG. 2 shows an automatic document feeder using this paper jam detection method. The automatic document feeder shown in FIG. 2 includes a document loading table 31, a transport belt 32, an optical system 33, a document size detection sensor, a stopper, a paper discharge roller, a feed roller, a discharge sensor, a control CPU, a RAM, and the like. Have.

In FIG. 1, an original loading table 31 is mounted at a predetermined position for copying an original. The transport belt 32 transports the document on the document loading table 31 before and after copying. The optical system 33 includes a lamp, a slit,
Scans the original on the original loading table 31
Copying is performed. The document size detection sensor detects a passage time when the document passes through the document size detection sensor when the document is fed onto the document loading table 33. The stopper is a member for positioning the document at a predetermined position on the document loading table 31. The feed roller and the paper discharge roller feed and discharge the document to the document loading table 31. The discharge sensor detects a document discharged from the document stacking table 31. The control CPU calculates a reference time based on a signal from the document size detection sensor,
This is stored in the AM unit, and when there is no signal from the discharge sensor within the reference time, it is determined that a paper jam has occurred.

In this automatic document feeder, a document is fed onto a document loading table 31 by a feed roller at the same time as the operation is started, and during this time, a document size detection sensor detects the passage time of the document and sends it to the control CPU. The control CPU calculates a reference time based on a signal from the document size detection sensor,
It is stored in the M section. Next, when the feeding of the document is completed, the transport belt 32 rotates in the reverse direction to switch the document, and abuts against the stopper to set the document at a predetermined position on the document loading table 31. When the document is set at a predetermined position on the document loading table 31, the optical system 33 scans the surface of the document to perform copying. When copying is completed, the paper discharge roller is activated to start discharging the original, and the feed roller is activated at a predetermined interval to feed the next original to the original loading table 31. Here, the discharge of the document is delayed for some reason, and there is no document detection signal from the discharge sensor, and when the time count reaches the reference time, it is detected that a paper jam has occurred.

Thus, in this automatic document feeder,
A paper jam is detected by comparing the time until the leading edge of the discharged document is detected with a reference time set according to the length of the document in the paper feeding direction.

[0007]

However, in the above-described conventional paper jam detection method, the reference time for paper jam detection is determined at the time when a document is copied.
The time to reach the paper ejection sensor changes depending on the length of the next fed document in the transport direction, so consider the reference time for paper jam detection to eliminate false detection of a paper jam. It must be set to the longest time you get. In particular, when a plurality of originals are placed on the contact glass, the time to reach the paper ejection sensor changes depending on the length of the next original to be fed in the transport direction. In order to eliminate erroneous detection, it is necessary to set the reference time for jam detection to the longest possible time.

In the above case, the reference time is set to be longer when the document is actually jammed, so that the possibility of damaging the document increases. SUMMARY OF THE INVENTION It is an object of the present invention to detect a document jam based on the length of the document on the contact glass and the document feed amount, thereby always performing appropriate paper jam detection regardless of the document size.

[0009]

According to the first aspect of the present invention,
In order to achieve the above object, a document transport device including: a transport unit that arranges a document transported from a document feed position on a contact glass; and a discharge unit that discharges the document from the contact glass to the outside of the apparatus. Document size detecting means for detecting the size of the document, document length recording means for recording the length of the document detected by the document size detecting means, and detecting the feed amount of the document discharged by the discharge means Document feed amount detection means, based on the document length stored by the document length storage means, and the document feed amount detected by the document feed amount detection means,
And a document jam detecting means for detecting a document jam.

According to a second aspect of the present invention, in order to achieve the above object, in the document transporting device according to the first aspect, the transporting means arranges a plurality of originals on a contact glass, and the original size detecting means comprises: The document size of each of the plurality of documents is detected, the document length recording unit records the length of the document, and the document feed amount detection unit detects
The sum of the feed amounts of the documents discharged by the discharge unit is detected, and the document jam detection unit detects the sum of the respective document lengths stored by the document length storage unit and the document feed amount detection unit. Document jamming is detected based on the sum of the detected document feed amounts.

According to a third aspect of the present invention, in order to achieve the above object, in the document transporting apparatus according to the second aspect, there is provided a document interval storage means for storing intervals of a plurality of documents arranged on the contact glass. The document jam detector detects the sum of the document intervals stored by the document interval storage, the sum of the respective document lengths stored by the document length storage, and the document feed amount detection. Document jam is detected based on the sum of the document feed amounts detected by the means.

According to a fourth aspect of the present invention, in order to achieve the above object, in the document feeder according to any one of the first to third aspects, the discharging means detects the document jam and the document jam detecting means detects the document jam. Then, the discharge of the document is stopped when it is performed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a document feeder according to the present invention. FIG. 1 is a diagram illustrating an example of an overall view of a document copying apparatus. A document conveying device 1 is mounted on an image forming apparatus 2. As shown in FIG. 1, the image forming apparatus 2 has an exposure unit, and includes a mirror 3, a lamp 4, a contact glass 19, an original scale 20, and a discharge tray 1.
The original set on the contact glass 19 is read by the mirror 3 and the lamp 4. At this time, the mirror 3 and the lamp 4 move to read the original.

The document feeder 1 includes a feed table 6, a document lifting member 7, a call roller 8, a separation belt 9, a separation roller 10, a first transfer roller 11, and a second transfer roller 1.
2, a transport belt 13, a first paper feed sensor 14, a second paper feed sensor 15, a paper discharge roller 16, and a paper discharge sensor 18, and a document 5 is stacked on a paper feed table 6. next,
The conveyance of the document 5 loaded on the document conveyance device 1 will be described. When a copy start button (not shown) of the document copying apparatus is pressed, the document 5 stacked on the sheet feeding table 6 is
The document is lifted by the document lifting member 7 and is pressed by the call roller 8. The document lifting member 7 is vertically moved by a bottom plate (document lifting member) vertical stepping motor (not shown). The call roller 8 rotates and feeds the sheet from the uppermost portion of the document 5 to the separation unit including the separation belt 9 and the separation roller 10. In the separation section, the originals 5 are separated one by one by the rotation of the separation belt 9 and the separation roller 10. The separated document is transported to the contact glass 19 by the first transport roller 11, the second transport roller 12, and the transport belt 13, and the image information is read. At this time, the document is stopped so that the rear end of the document is positioned on the document scale 20. The document 5 is sequentially fed from the top, and when the final feeding is completed, the document lifting member 7 is lowered. The call roller 8, the separation belt 9, the separation roller 10, the first transport roller 11, and the second transport roller 12 are all driven by a paper feed stepping motor (not shown), and the transport belt 13 is driven by a transport stepping motor (not shown). Since the paper feed stepping motor and the transport stepping motor can be driven independently,
Arbitrarily changing whether the next original is fed after the original on the contact glass 19 is discharged, whether a plurality of originals are arranged on the contact glass 19, and how much the interval between the arranged originals is set. Can be. Near the downstream side of the first transport roller 11 and the second transport roller 12, a first paper feed sensor 1 for jam detection and document length detection is provided.
4 and a second paper feed sensor 15. First paper feed sensor 1
The document length information detected by the fourth and second paper feed sensors 15 is stored in the document length storage memory when the document is conveyed onto the contact glass 19 for reading image information and stopped. At this time, the contact glass 19
If there is only one upper document, it is stored in the first storage memory, if there is a second document, in the second storage memory, if there is a third document, it is stored in the third storage memory, and so on. .

After the reading of the image has been completed, the document that has reached the paper discharge unit is discharged to a paper discharge tray 17 by paper discharge rollers 16. By counting the pulses of the transport stepping motor while the document is being transported to the paper discharge unit, the amount of document transport on the transport belt 13 can be known. A paper discharge sensor 18 is provided in the paper discharge unit, and detects a paper discharge jam and a paper discharge deceleration timing.

Next, the timing of detecting a jam will be described. The document on which the image reading has been completed is sent to the paper discharge unit by the transport belt 13, but the transport belt 13 does not always continue to be driven until it reaches the paper discharge sensor 18. Contact glass 19 to increase document processing speed
When a control is performed on which a plurality of originals can be arranged, the transport belt 13 stops for reading the next original depending on the length of the next original in the transport direction. Then, as the length of the document after the next document is shorter, the number of times the transport belt 13 stops before the document reaches the paper ejection sensor 18 increases. Since the size is detected by the first paper sensor 14 and the second paper sensor 15, the size cannot be detected until the document passes through the first paper sensor 14 and the second paper sensor 15. Also, all the continuously fed documents are not necessarily the same size.

Therefore, in the prior art, in a document feeder in which a plurality of documents of different sizes can be arranged on the contact glass 19, an appropriate jam detection (detection of a paper jam that has not reached the paper discharge unit) cannot be performed. Therefore, in the present invention, when the condition of the following equation (1) is satisfied, even though the paper ejection sensor 18 does not detect the original, it is determined that the paper jam has not been reached and all the driving related to the conveyance is stopped. By doing so, it is possible to accurately prevent the document from being damaged when a jam occurs.

X> Lse− (G1 + G2 + G3...) + Α (1) where, Lse: distance between document scale 20 and paper discharge sensor 18 G1: top document on contact glass 19 stored in first storage memory G2: Length of the second document on the contact glass 19 stored in the second storage memory G3: Length of the third document on the contact glass 19 stored in the third storage memory α: Slit, etc. Considerable jam detection margin X: Indicates the distance that the conveyor belt 13 has been conveyed since the last stop. The value of Gn stored in the storage memory exceeding the number of originals on the contact glass 19 is 0.

Next, an embodiment in which the document interval is taken into consideration will be described. In the above embodiment, the interval between the originals arranged on the contact glass 19 is not taken into consideration. Therefore, when the number of documents arranged on the contact glass 19 increases, or when the control for changing the document interval according to the size or the like is performed, the optimum jam detection cannot be performed in the above embodiment.

In the present embodiment, when the condition of the following equation (2) is satisfied, the paper ejection sensor 18 does not detect the original, but it is determined that the paper jam has not been reached, and all the driving related to the conveyance is performed. Is stopped, the document can be more accurately prevented from being damaged in the event of a jam. X> Lse− (G1 + G2 + G3... + D12 + D23...) + Α (2) where, Lse: distance between the document scale 20 and the paper ejection sensor 18 G1: Length G2: Length of second document on contact glass 19 stored in second storage memory G3: Length of third document on contact glass 19 stored in third storage memory D12: On contact glass 19 D23: Distance between the second and third documents on the contact glass 19 α: Margin detection margin in consideration of slits and the like X: Transport belt 13 stops last It indicates the distance transported from to the present. The value of Gn stored in the storage memory exceeding the number of documents on the contact glass 19, and Dn related to the document exceeding the number of documents on the contact glass 19
The value of n + 1 is 0.

As described above, the jamming of the original can be accurately detected, the conveyance of the jammed original can be stopped quickly, and the original can be prevented from being damaged.

[0022]

According to the first aspect of the present invention, since the length of the original and the amount of the original fed are detected, the length of the original to be conveyed normally can be grasped, and the jam of the original is detected. be able to. According to the second aspect of the invention, since the sum of the lengths of the respective originals and the sum of the feed amounts of the originals are detected, it is possible to know the length that should be normally conveyed even for a plurality of originals. Thus, a document jam can be accurately detected.

According to the third aspect of the present invention, in addition to the second aspect of the invention, since the sum of the document intervals can be detected, the document transport amount including the document intervals can be accurately grasped.
Document jams can be detected. According to the fourth aspect of the present invention, the discharge of the document is stopped when the document jam is detected. Therefore, it is possible to prevent the transport operation from being forcibly performed while the document is jammed, and to prevent the document from being damaged. In addition, it is possible to prevent unnecessary waste paper from being left in the apparatus and adversely affecting the apparatus.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a document copying apparatus equipped with a document conveying device according to the present invention.

FIG. 2 is a diagram illustrating an example of a conventional automatic document feeder.

DESCRIPTION OF SYMBOLS 1 Document feeder 2 Image forming device 3 Mirror 4 Lamp 5 Document 6 Feeding table 7 Document lifting member 8 Recall roller 9 Separation belt 10 Separation roller 11 First transport roller 12 Second transport roller 13 Transport belt 14 First feed sensor 15 Second feed sensor 16 Discharge roller 17 Discharge tray 18 Discharge sensor 19 Contact glass 20 Original scale 31 Original loading table 32 Transport belt 33 Optical system

Claims (4)

[Claims] 1. A document transport device comprising: transport means for arranging a document transported from a document feed position on a contact glass; and discharge means for discharging the document from the contact glass to the outside of the apparatus. Document size detecting means for detecting the size of the document, document length recording means for recording the length of the document detected by the document size detecting means, and a document for detecting the feed amount of the document discharged by the discharging means Document feed detecting means, based on the document length stored by the document length storage means and the document feed amount detected by the document feed amount detecting means, document jam detecting means for detecting document jam, A document feeder comprising: 2. The document conveying device according to claim 1, wherein said conveying means arranges a plurality of originals on a contact glass, and said original size detecting means detects respective original sizes of said plurality of originals. The document length recording unit records the length of the document, the document feed amount detection unit detects the sum of the feed amount of the document discharged by the discharge unit, and the document jam detection unit Detecting a document jam based on the sum of the respective document lengths stored by the document length storage means and the sum of the document feed amounts detected by the document feed amount detection means; Document feeder. 3. The document feeder according to claim 2, further comprising: document interval storage means for storing intervals of a plurality of documents arranged on said contact glass; The sum of the respective document intervals stored by the storage means, the sum of the respective document lengths stored by the document length storage means, and the sum of the document feed amounts detected by the document feed amount detection means. A document feeder for detecting a document jam based on the document feeder. 4. The document conveying device according to claim 1, wherein said discharging means stops discharging the document when said document jam detecting means detects a document jam. Document feeder that performs