JPH06227704A - Automatic document feeder - Google Patents

Abstract

PURPOSE:To shorten a stop to an image read position of the initial document by detecting whether a document is left or not in a short time. CONSTITUTION:A duplex sensor 34 is provided adjacently to an image read reference position 33 in an inverting path 31 for inverting a document. In order to detect a residual document on a platen glass 18, a drive belt 25 for a preset time or its stepping motor only by a predetermined rotational speed are reversely driven, and when detected no residual document for a fixed time or pulse number reverse driving during this time, the residual document is determined not provided, to start feeding a normal document. When detected the residual document, a device is stopped or the residual document is discharged through the inverting path. By shortening a conveying distance to a direction of the inverting path of the residual document to detect whether it is provided or not in a short time, a stop in a reference position of the document can be shortened, to enable productivity to improve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic document feeder in a recording device such as a copying machine, a printer, a facsimile, etc., and more particularly, a remaining document discharge for performing a normal document feed in executing a job set by a user. The present invention relates to an automatic document feeder having a processing function.

[0002]

2. Description of the Related Art Recently, with the development of high precision, high speed, miniaturization and the like of a recording apparatus, as a means for efficiently performing various job functions, an automatic document feeder has been used. The functions and performance are improved.

The automatic document feeder automatically sets a document on the platen glass and is usually prepared as an option so that the user can selectively equip the base machine. This device feeds the documents set on the document tray one by one at the timing of image processing from the document inlet through the transport path, transports them on the platen glass by the endless belt, and after the document image is read, through the discharge transport path. The document is discharged to the document discharge tray.

By the way, the automatic document feeder is roughly divided into a tray section for placing originals before and after processing, a carry-in section for feeding originals, a registration section for laying originals at a low position on the platen glass, and an original after processing. It is composed of a document discharge section for removing the sheet from the platen glass. Each of the above-mentioned units is provided with an independent or subordinate transport roll mechanism for transporting a document, and the drive system of this transport roll mechanism feeds and transports the document from the tray section to the document pull-in transport path (pre-feed). A DC motor is used as a feed motor for feeding the original, and a belt motor for simultaneously driving a registration roll for feeding and feeding the original and a belt for laying and feeding the original on the platen glass and discharging the original. Stepping motors are used for each exit motor. The originals set on the tray are sent one by one to the original feeding and conveying path by the nudger roll and the retard mechanism, then drawn by the registration roll at the timing of image processing, and further registered by the belt at the registration position on the platen glass. Is laid in.

After the document image is read, the belt motor and the exit motor are driven, and the document sent from the platen glass is discharged to the document discharge tray through the discharge transport path. In such a configuration, when performing image processing according to the set job,
The document transport mode for each job is set up on the assumption that there is no document for the previous job in the automatic document feeder. Therefore, in order to perform various document transport modes in a normal operation, the documents in the previous job must not be placed on the carry-in section, the platen glass, and the discharge / carry-in path. Therefore, the user starts a job after checking whether or not there are remaining originals when setting the originals.

Many proposals have hitherto been made as means for detecting or discharging the above-mentioned remaining originals.
For example, as disclosed in Japanese Examined Patent Publication No. 2-14253, the remaining original is detected by means such as opening / closing detection of the original conveying section, and the next original is drawn in after the remaining original is discharged. As described in Japanese Laid-Open Patent Publication No. 55-111956, there is known one that prohibits the document feeding operation when a remaining document is detected. In addition, JP-A-61-1
As disclosed in Japanese Patent No. 270740, it is known that a detector for detecting the presence / absence of a document is provided at the entrance of a discharge section and the sheet feeding operation is stopped when the detector detects a remaining document. Further, as described in Japanese Patent Application Laid-Open No. 2-23132, there is known a technique of ejecting a document in a direction opposite to the conveying direction by reversing the conveying roll of the automatic sheet feeder for a predetermined time.

However, in the case of detecting the open / closed state of the document feeding portion and the remaining document by detecting the document, the document of a small size or the document may not be detected when the document is not at a predetermined position. , The remaining originals cannot be ejected reliably. Recently, there has been proposed a device for detecting the trailing edge of a document placed on the platen and stopping the document at the reference position in order to improve productivity. In addition to the document pull-in operation, the remaining document discharge operation for transporting the distance from the reference position of the platen to the detection unit of the discharge unit is required regardless of the presence or absence of the document. In this case, since the reference position is at the rear end of the document, the transport distance becomes long, and it takes time from the pressing of the copy start button to the completion of copying. Further, if the discharging operation is performed for a predetermined time each time before the automatic copying operation is started, the copying operation must be waited for a predetermined time regardless of whether or not the original document is forgotten to be taken, which causes a problem of lowering productivity. . An object of the present invention is to provide an automatic document feeder that can detect the presence or absence of a remaining document in a short time and shorten the stop of the first document at the image reading position. Another object of the present invention is to provide an automatic document feeder which can easily distinguish the discharged remaining original document from the normally discharged original document.

[0007]

In order to achieve the above object, the present invention according to claim 1 separates the originals one by one and supplies them to the original reference position for image reading, and at the same time, reads the image of the original. In an automatic document feeder for performing a reversing operation or a discharging process later, a detecting unit arranged near the document reference position in a reversing path for reversing the document, and detecting means for detecting the presence or absence of the document, and the document reference position. A driving unit that discharges a certain document or supplies the document to an inversion path, and operates the driving unit for a predetermined time before starting the image reading operation of the document to reverse the remaining document at the document reference position. It is configured to be conveyed to a road and detected by the detecting means. According to a second aspect of the invention, in the first aspect of the invention, the discharging process is executed on condition that the remaining document is detected within a predetermined time of the driving means or by a reversing operation at a predetermined rotation speed or less. It is in. According to a third aspect of the present invention, in the second aspect of the invention, the remaining document discharging process is performed through the inversion path. According to a fourth aspect of the invention, in the first aspect of the invention, the drive means is stopped on condition that the detection means detects the remaining original document. According to a fifth aspect of the invention, in the invention of the first aspect, the driving source of the driving means is a stepping motor, and the stepping motor is reversed by a predetermined number of pulses before starting the image reading operation of the original document. It is configured to detect the presence or absence of a document.

[0008]

In the above construction, when the automatic copying operation is started, the driving means is reversely driven in the direction of the reverse path for a certain period of time, and if the detecting means provided in the reverse path does not detect the remaining original within this time, there is no remaining original. Judge and execute normal copying by automatic document feeding. If the detection unit detects the remaining document,
The remaining document is reversed in the reverse path and discharged to the discharge tray.
In the above operation, by providing the detecting means at the position closest to the reference position of the reversing path, it is possible to detect the presence or absence of the remaining document in a short time. Further, since the detected remaining original document is reversed through the reversing path and discharged to the discharge tray, the front and back surfaces of the original document are reversed and can be easily identified.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The present embodiment is applied to a copying machine, and is configured by combining an additional device such as a double-sided automatic document feeder (DADF) with a base machine. In the copying machine, a DADF 2 is attached to a base machine 1 as shown in FIG. 2, and an electrostatic latent image is formed on a photosensitive drum 4 by image information read by an optical reading device 3 from a document sent by the DADF 2. To do. The photosensitive drum 4 on which the electrostatic latent image is formed is developed by the developing device 5, and toner is supplied to form a toner image. The toner image is transferred onto the paper of the designated size supplied from the paper tray 6 by the transfer corotron 7, thermally fixed by the fixing device 8 and discharged to the discharge tray 9.

The structure of the DADF 2 is shown in FIG. In FIG. 1, a nudger roll 1 is provided on the discharge side of the document tray 11 to feed out documents (not shown) accumulated on the document tray 11.
2 and a feed roll 13 and a retard roll 14 for separating the originals one by one. A set gate 15 is provided between the nudger roll 12 and each of the rolls 13 and 14 to abut the document. The set gate 15 is moved by a solenoid 16 to abut or release the document. A document sensor 17 for detecting the presence or absence of a document is arranged on the document tray 11.

In the supply path 19 for conveying the original from the roll pair 13, 14 onto the platen glass 18 as the original table,
A registration roll 20 for correcting skew of the document is provided, and a registration sensor 21 is arranged in front of the registration roll 20 in the supply path 19, and the length of the document is detected by the time when the document passes through the registration sensor 21. In addition, the supply path 19
Is provided with a pair of size sensors 22 and 23 for detecting the width of the document at almost the same position in the feeding direction, and the three sensors 21, 22 and 23 identify the type of the document. .

On the platen glass 18, there is provided a conveyor belt 25 as a driving means stretched between a pair of belt driving rollers 24, and the conveyor belt 25 is supported by a plurality of pinch rollers 26. . Then, one of the belt drive rolls 24 is rotationally driven in the counterclockwise direction by a belt drive motor (not shown) to convey the document supplied on the platen glass 18 in the direction indicated by the arrow A, and to the discharge path 27 on the downstream side. Two pairs of discharge rolls 28 provided are used to discharge to a discharge tray 29. In addition, an exhaust sensor 30 for detecting the discharged document is arranged in the discharge path 27. On the other hand, an inverting path 31 for inverting the original is provided on the upstream side of the conveyor belt 25, and the inverting path 31 is provided with two pairs of inverting rolls 32. Further, the platen glass 18 is provided in the inversion path 31.
A duplex sensor 34 is installed close to a reference position 33 that is set above and determines the trailing edge position of the original,
The document in the reverse path 31 is detected.

FIG. 3 shows the structure of a drive system for each roll. The registration roll 20, the belt driving roll 24, and the pair of reversing rolls 32 are rotationally driven by a belt motor 41, respectively.
And the reversing roll 32 rotates normally. In addition, the belt motor 41
At the time of reverse rotation, the registration roll 20 does not rotate, the belt drive roll 24 rotates reversely, and the reverse roll 32 rotates forward. Najar roll 12 and feed roll 1
3 is forwardly rotated by the forward rotation of the feed motor 42, and the two pairs of discharge rollers 28 are normally rotated by the discharge motor 43. The belt motor 41 is a stepping motor, the rotation of which is controlled by a signal that the registration sensor 21 detects the passage of the document, so that the rear end of the document is correctly positioned at the reference position 33 on the platen glass 18. For double-sided originals, the belt motor 4
1 rotates in the opposite direction to feed the document into the reversing path 31, and after the document is completely fed into the reversing path 31, rotates in the forward direction.

FIG. 4 shows a schematic structure of the control unit. CPU5
1, a start signal 52, a document feed mode signal 53, a document replacement signal 54, an input signal 55 from each sensor, and an interlock input signal 56 are input, and the CPU 51 outputs a document size information 57, a document setting signal 58, each. The solenoid drive signal 59 and each motor drive signal 60 are output.

Next, the operation of this embodiment will be described with reference to FIGS. FIG. 6 shows a timing chart when there are no remaining originals. FIG. 9 shows a timing chart when there are remaining originals. Platen glass 18 as shown in FIG.
When there is no remaining document on the upper side, as shown in (a), the document 61 is piled up on the document tray 11 with the front side facing up, and the start gold port of the operation panel (not shown) is pushed. Then, as shown in (b), the belt motor 41 rotates in the reverse direction and the conveyor belt 25 moves in the direction of arrow B.
Driven in the direction. Then, the duplex sensor 34 does not detect the remaining document even after a predetermined time has elapsed. This predetermined time is predetermined by the number of pulses applied to the belt motor 41. Next, as shown in (c), the reverse rotation of the belt motor 41 is stopped, and at the same time, the supply of the original 61 set on the original tray 11 is started, the original 61 is laid on the platen glass 18, and the normal operation is performed. Duplicate according to the procedure.

As shown in FIGS. 7 and 8, when the remaining original 71 is present on the platen glass 18, when the start key is pressed in (a) as in the case shown in FIG. The remaining original 71 is driven in the B direction.
Is conveyed into the reverse path 31 and the remaining original 71 is detected by the duplex sensor 34. Next, in (c), after the duplex sensor 34 detects the remaining original 71, the reverse rotation of the belt motor 41 is stopped and a normal rotation is started after a certain time has elapsed by pulse counting. Then, the remaining original document 71 conveyed on the platen glass 18 through the reversing path 31 is sent in the direction of arrow A by the carrying belt 25 as shown in (d), guided to the discharging path 27 and discharged by the discharging roll 28. It is discharged onto the tray 29. Then (e)
After the remaining original 71 is discharged as shown in FIG.
The feeding of the normal document 61 set at is started, and copying is performed in the normal procedure.

According to this embodiment, since the duplex sensor 34 is provided close to the reference position 33 of the platen glass 18, the remaining original document 7 on the platen glass 18 is provided.
The distance to move the drive belt 25 in the direction of arrow B in order to detect the presence or absence of 1 can be shortened.
It is possible to shorten the time required to reach the reference position 33 on the upper surface 8 and stop it, and improve the productivity. Further, when the remaining original 71 exists, the discharged remaining original 71 is reversed, and since the front and back sides of the normally discharged original 61 are opposite, it is possible to easily identify the remaining original 71. it can.

In the present embodiment, the misplaced original is described as the remaining original, but the original is jammed in the apparatus (jam), and after the jam is cleared, the presence or absence of the jammed original is detected and the inside of the apparatus is detected. It can also be applied when ejecting the originals remaining in the. In this case, it is not possible to specify where in the apparatus the remaining document is, so the time required for detection by the preset reverse rotation drive is set.

[0019]

As described above, according to the present invention,
Since the detecting means for detecting the presence / absence of the remaining original document is provided in the reversing path, the time for reversing the driving means for detecting the presence / absence of the remaining original document on the platen glass is shortened, and the productivity can be improved. Further, when there is a remaining document, the discharged remaining document is reversed, so that it can be easily distinguished from the normally discharged document.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an overall configuration of an embodiment of an automatic document feeder according to the present invention.

FIG. 2 is a schematic diagram showing a schematic configuration of an example of a copying machine equipped with an automatic document feeder.

FIG. 3 is a diagram for explaining a drive system.

FIG. 4 is a block diagram showing a configuration of a control system.

FIG. 5 is a diagram for explaining a document operation mode without a remaining document.

FIG. 6 is a timing chart in a document operation mode without a remaining document.

FIG. 7 is a diagram for explaining up to the reversing operation of the remaining document in the document operation mode with the remaining document.

FIG. 8 is a diagram for explaining after the operation of discharging the remaining document in the document operation mode with the remaining document.

FIG. 9 is a timing chart in a document operation mode with a remaining document.

[Explanation of symbols]

1 copy machine, 2 automatic document feeder, 11 document tray, 18 platen glass, 21 discharge path, 25 conveyor belt, 34 duplex sensor, 31 reverse path,
33 reference position, 61 originals, 71 remaining originals

Claims (5)

[Claims] 1. An automatic document feeder for separating documents one by one and feeding them to a document reference position for image reading, and for performing a reversing operation or a discharging process after image reading of the documents, for reversing the documents. The original document includes: a detection unit that is provided near the document reference position in the inversion path and detects the presence or absence of the document; and a drive unit that discharges the document at the document reference position or supplies the document to the inversion path. The automatic document feeder, characterized in that the drive means is operated for a certain period of time before the image reading operation, and the remaining original document at the original document reference position is conveyed to the reverse path and detected by the detection means. 2. The automatic original document according to claim 1, wherein the discharge process is executed on condition that the remaining original document is detected within a predetermined time of the driving means or during a reversing operation at a predetermined rotation speed or less. Feeder. 3. The automatic document feeder according to claim 2, wherein the discharging process of the remaining document is performed through a reversing path. 4. The automatic document feeder according to claim 1, wherein the drive unit is stopped on condition that the detection unit detects the remaining document. 5. A stepping motor is used as a driving source of the driving means, and the stepping motor is reversed at a predetermined pulse number to detect the presence or absence of a remaining original before the image reading operation of the original is started. The automatic document feeder according to claim 1.