JPH11255395A - Sheet conveying apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable sure deceleration at the time of discharging a sheet by decelerating a paper discharge roller at a fixed position from the trailing end of a sheet when the length of the sheet detected by a size detecting means is larger than a designated length and from the leading edge of the sheet when it is smaller than a designated length. SOLUTION: To start to discharge a document at a high speed and lower the speed, in the course to discharge the document with good alignment to a paper discharge tray, first the length of the fed document is detected by a document size detecting means. According to the length, the amount of time from a paper discharge sensor 110 detects the leading edge of the document until the paper discharge roller 111 is decelerated is set. When the paper discharge sensor 110 detects the leading edge of the document, according to the preset value, the paper discharge roller 111 is decelerated from high speed to low speed. The deceleration time of the paper discharge roller is determined by the document reaches the paper discharge sensor 110, and even if the distance between the paper discharge sensor 110 and the paper discharge roller 11 is small, the document is not discharged without deceleration unlike the prior art.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying device such as an automatic document feeder for supplying and conveying a document on a platen of an image processing device such as a copying machine and an image reader.

[0002]

2. Description of the Related Art An automatic document feeder attached to an image forming apparatus, for example, a copying machine, feeds out originals set on an original tray one by one, transports the originals on a platen by a transport belt, and stops the originals at a reference position. Copying is performed, and after the copy is completed, the original is again conveyed from above the platen by the conveying belt, and is discharged to a discharge tray by a discharge roller.

In such an automatic document feeder,
In order to improve the alignment of the documents discharged to the paper discharge tray, for example, as described in Japanese Patent Application Laid-Open No. 56-12248, when a document whose copy has been completed is discharged to the paper discharge tray, the document is provided in front of a paper discharge roller. When the paper discharge sensor detects the trailing end of the document, the paper discharge roller is decelerated, and the document being discharged is switched from the middle to a low speed and discharged.

[0004]

As described above, when the discharge roller is decelerated after the discharge sensor detects the rear end of the document,
If the distance between the paper discharge sensor and the paper discharge roller is short, the document is discharged without being decelerated.

If the distance between the paper discharge sensor and the paper discharge roller is long, it is not possible to detect jamming of the document between the paper discharge sensor and the paper discharge roller. Therefore, the mounting position of the paper ejection sensor is restricted.

Although the paper discharge speed varies depending on the type of copying machine, if the automatic document feeder is installed commonly to these copying machines, the distance between the paper discharge sensor and the paper discharge roller is constant. In the case of high speed, between the time when the paper discharge sensor detects the trailing edge of the original and the time when the paper discharge roller is decelerated,
In some cases, the trailing edge of the document passes through the paper discharge roller, and the paper cannot be discharged at a reduced speed.

As a solution to these problems, for example,
The length of the document conveyed is detected by the size detection means, and the length of the document detected by the size detection means is determined after the discharge sensor detects the leading end of the document supplied to the discharge section after copying is completed. It is conceivable that when the sheet is conveyed by an amount obtained by subtracting a predetermined amount from the sheet, that is, at a position that is a predetermined length before the trailing end of the discharged document, the discharge roller is switched from high speed to low speed, and the paper is discharged at a reduced speed.

However, if the deceleration is switched to a low speed at a fixed position from the rear end of the original, the original may be discharged without being reduced depending on the size of the original.

This invention is based on the idea that, for documents of various sizes that need to be decelerated to improve alignment, the documents are decelerated to a low speed at least before the trailing edge of the sheet is completely out of the paper discharge roller, and the paper is discharged when the sheet is discharged. It is an object of the present invention to obtain a sheet conveying device capable of reliably decelerating and discharging.

[0010]

An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, an automatic document feeder 5 is mounted on a platen 3 (document setting surface) of an image processing apparatus such as a copying machine 1.

The automatic document feeder 5 includes a document tray 7
A feeding unit 9 for separating the original set on the original tray 7 into one sheet and sending the separated original; a conveying unit 11 for conveying the original sent from the feeding unit 9 on the platen 3; And a discharge tray 1 for storing the documents discharged from the discharge unit 13.
5 and a control device (not shown) so as to automatically feed and discharge a document. Note that the transport unit 11 and the discharge unit 13 are integrated with the cover C, and are attached to the back of the copying machine 1 via a hinge so as to be manually opened and closed.

The feeding section 9 is configured as shown in FIG.

First, a paper feed path 19 is formed by the guides 23, 24, and 25, and a separation roller 31 and a paper feed roller 33 are arranged to face each other.

The separation roller 31 is attached to the rotation shaft 35 via a one-way clutch, and is driven to rotate by the motor 27 in a direction opposite to the sheet feeding direction (clockwise in the drawing). The paper feed roller 33 is also attached to the rotating shaft 37 via a one-way clutch, and is driven to rotate in the paper feed direction (clockwise in the drawing) by the motor 27.

The separation roller 31 is pressed against the paper feed roller 33 by the solenoid 32 or is separated from the paper feed roller 33.

A connecting portion 39 is connected to the shaft 37 of the sheet feeding roller 33.
An arm 43 having a locking portion 41 is rotatably mounted. A pickup roller 47 is attached to the connecting portion 39 via a rotation shaft 45, and rotates together with the sheet feeding roller 33 via timing pulleys 44 and 46 and a timing belt 49.

In the vicinity of the pickup roller 47, a lever type sensor 48 for detecting whether or not the document P is set on the document tray 7 is attached.

Above the arm 43, a lever 55 attached to a shaft 53 driven by a latching (keep) solenoid 52 is provided. The lever 55 supports the locking portion 41 and locks the rotation of the arm 43.

A set stopper 59 attached to a shaft 57 driven by the latching solenoid 52 is provided to prevent the document P from entering the paper feed path 19 when the document P is lowered.

In the latching solenoid 52, for example, a permanent magnet is used in parallel with the magnetic circuit of a DC solenoid. When an instantaneous current is applied to the solenoid, the iron core in the solenoid is attracted and the state is held by the permanent magnet. When an instantaneous current having a polarity opposite to that of the attraction is applied to the solenoid, the holding force of the permanent magnet is weakened, and the iron core is returned by a return spring.

In front of the separation roller 31 and the paper feed roller 33, registration rollers 51 and 54 are provided. The registration roller 51 is driven by a motor 56.

A clock plate 61 having a plurality of holes provided at equal intervals on the same circumference is attached to the rotating shaft of the motor 56, and an optical sensor 62 having a light emitting element and a light receiving element.
By detecting the hole of the clock plate 61 as a pulse, the rotation amount of the motor 56 can be detected.

A lever type contact sensor 63 is provided at the entrance of the registration rollers 51 and 54, and an optical non-contact sensor 64 is provided on a contact portion between the registration rollers 51 and 54. Is provided.

As shown in FIG.
The roller 1 is supported at both ends by rollers 83 and 85, and is pressed against the platen 3 by a roller 87 at the middle. The roller 85
Are driven by a motor 91 (drive device).

A clock plate 93 is attached to the rotation shaft of the motor 91 so that the rotation amount can be detected by the sensor 65.

As shown in FIG.
1, a paper discharge roller 107, 109, 111, 113, a paper discharge sensor 110, and a paper discharge port 114.
The paper discharge rollers 107 and 111 are driven by the motor 91.

The control device includes, for example, a microcomputer, and based on signals from sensors 48, 62, 63, 64, 65, 110, solenoids 32, 52 and motors 27, 56, 9
1 and the like, and the processing shown in FIGS. 5 and 6 is performed.

The operation of the apparatus having the above configuration will be described with reference to FIGS.

First, when the document P is set on the document tray 7 with its front surface facing down, the sensor 48 detects the document and automatic document feeding becomes possible.

In this state, when a paper feed button (not shown) of the automatic document feeder 5 is pressed, the paper feed operation starts in step S1 in FIG. Therefore, the latching solenoid 52 and the solenoid 32 in FIG. 3 are excited. The lever 55 rotates counterclockwise in the figure by the excitation of the solenoid 52. For this reason, the pickup roller 47 falls on the document.

The shaft 57 is excited by the excitation of the solenoid 52.
Rotates clockwise, and the set stopper 59 rotates upward. Therefore, paper can be fed. Further, the separation roller 31 is pressed against the paper feed roller 33 by the excitation of the solenoid 32.

When the pickup roller 47 comes into contact with the original P on the original tray 7, the motor 27 is rotated. Thereby, the sheet feeding roller 33 and the pickup roller 47
Rotates in the paper feeding direction, and the separation roller 31 rotates in the direction opposite to the paper feeding direction.

The document on the document tray 7 is sent out by the rotation of the pickup roller 47, and the document following the document is fed by the feed roller 33 while being rejected by the separation roller 31. Then, the sensor 63 detects the leading edge of the document, and the leading edge of the document is abutted against a contact portion between the registration rollers 51 and 54. Since the document is further fed by the paper feed roller 33 while the leading edge of the document is locked, the document is bent and the leading edge of the document is registered.

As shown in FIG. 4, T1 time after the sensor 63 detects the leading edge of the document, the solenoid 32 and the motor 27
Stop the energization.

For this reason, the motor 27 stops, the feeding of the document stops, and the separation roller 31
Separated from At this time, since the pickup roller 47 is in contact with the document, the deflection of the document is maintained.

At time T2 after the sensor 63 is turned on, the motors 56 and 91 are rotated and the solenoid 52 is reversely excited. Accordingly, the registration roller 51 and the transport belt 81 rotate, and the pickup roller 47 moves up.

The rotation of the motors 56 and 91 causes the sensors 62 and
Reference numeral 65 detects pulses from the clock plates 61 and 93. The document that has been registered is sent out by the rotation of the registration roller 51, and is detected by the sensor 64. When the trailing edge of the document passes the sensor 64, the sensor 64 is turned off and the motor 56 stops. Further, the motor 91 is decelerated.

By the way, the contact type sensor 63 which has a slow response speed but does not hinder the detection of the original even if there is a black portion in the original.
When the non-contact type sensor 64 detects the original, the response speed is high but the black portion on the detection line of the original causes an error in the original detection.
The start point of the rotation amount detection of the (motor 56) is obtained. The time when the sensor 63 stops detecting the document after the sensor 63 stops detecting the document is regarded as the end point of the rotation amount detection of the registration roller 51 (motor 56). The corresponding document size (length) is detected in step S2 in FIG. 5 according to the number of pulses of the size clock signal to be obtained.

For this reason, even if one of the sensors 63 and 64 is temporarily turned off during the period from the starting point to the end point, the other sensor detects the original, and the reliable size detection is performed. Done.

The non-contact sensor 64 compensates for the slow response speed, which is a drawback of the contact sensor 63, and compensates for the detection error of the black portion, which is a drawback of the non-contact sensor 64, by the contact sensor 63. .

It is determined whether the detected original is longer than, for example, 70 mm in step S3 in FIG. The 70 mm is for decelerating 70 mm before the rear end of the document.

If the length of the document is shorter than 70 mm, the timer value is set to a minimum in step S4.

If it is longer than 70 mm, the process proceeds to step S5.
Calculate the timer value for (length-70 mm).

Then, in step S6, steps S4, S
The timer value set in step 5 is stored.

The original sent from the feeding section 9 is conveyed on the platen 3. Then, after a lapse of T3 time since the sensor 64 was turned off, the motor 91 is stopped, and the original is moved to the copy position.
(Reference position).

By the way, after the motor 91 stops, T4
After a lapse of time, the solenoids 32 and 52 are excited, and the next original is advanced to the position of the registration roller 51.

The original set at the copy position is
When copying is completed, step S in FIG.
7, the paper discharge operation starts, the motor 91 rotates, and the document is supplied to the reversing path 101.

The motor 56 and the solenoid 52 are energized seven hours after the rotation of the motor 91, and the advanced document is sent out onto the platen 3. That is, after the discharge operation of the original on the platen 3 is started, the advance original is sent out onto the platen 3.

Then, in step S8, the paper ejection sensor 110
Detects the leading edge of the original, the motor 91 is decelerated, for example, after a time T5 in step S9 according to the timer value stored in step S6, and the discharge speed of the original discharged from the discharge port 114 is reduced from the middle, and The document is slowly discharged to the discharge tray 15.

The original document is set at a low speed at the copy position on the platen 3 by the speed reduction of the motor 91.

In this manner, a plurality of originals are sequentially sent out, copied, and discharged.

According to the above-described embodiment, the length of the fed document is detected in order to start discharging the document at a high speed, and to lower the speed halfway to discharge the document to the discharge tray 15 with good alignment.
According to this length, a time period from when the paper discharge sensor 110 detects the leading edge of the document to when the paper discharge roller 111 is decelerated is set. Since the paper roller 111 is decelerated from high speed to low speed, the deceleration timing of the paper discharge roller 111 is determined before the document reaches the paper discharge sensor 110, and the distance between the paper discharge sensor 110 and the paper discharge roller 111 is reduced. However, there is no fear that the document is discharged without being decelerated as in the related art. Therefore, there are few restrictions on the mounting position of the paper ejection sensor 110.

Further, since the distance between the paper ejection sensor and the paper ejection roller can be set to be short, it is possible to prevent a jam of the document between the paper ejection sensor 110 and the paper ejection roller 111 from being detected.

Further, when the paper discharge speed varies depending on the type of copying machine, even if this automatic document feeder is attached to these copying machines in common, if the speed is high as in the conventional case, the paper discharge sensor will be There is no possibility that the trailing edge of the document passes through the discharge roller between the time when the end is detected and the time when the discharge roller is decelerated.

Further, since the document is decelerated at the deceleration start position determined based on the length of the document, the document is reliably discharged at a reduced speed.

It should be noted that even if the paper discharge speed or the position at which the paper discharge sensor is attached is changed, the same control can be performed only by changing the set value according to the length of the document.

[Modifications] Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and for example, the following modifications are possible.

(1) In the above-described embodiment, the length of the original is detected by the paper supply unit 9, but may be detected before the leading end of the original reaches the paper discharge sensor 110.

(2) In the above embodiment, the discharge roller is decelerated a set time after the paper discharge sensor 110 detects the leading edge of the document. You may do it.

(3) The present invention can also be applied to an automatic document feeder having a front / back reversing function for setting both sides of a two-sided document one by one on a document setting surface and performing image processing on both sides of the document, and a device for transporting a card. it can.

[0062]

[Brief description of the drawings]

FIG. 1 is a plan view illustrating a configuration of an automatic document feeder.

FIG. 2 is a cross-sectional view illustrating a configuration of the automatic document feeder.

FIG. 3 is a diagram illustrating a configuration of a separation feeding unit.

FIG. 4 is a timing chart for explaining an operation.

FIG. 5 is a flowchart illustrating an operation.

FIG. 6 is a flowchart illustrating an operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Copier 3 Platen 5 Automatic document feeder 7 Document tray 9 Separation feeding part 11 Conveying part 13 Discharge part 15 Discharge tray 31 Separation roller 33 Feed roller 47 Pickup roller 51,54 Registration roller 56 Motor 81 Transport belt 91 Motor 107,111 discharge rollers

Claims (2)

[Claims] A transport unit configured to transport a sheet fed from a feeding unit to a predetermined position; a discharge unit having a discharge roller configured to discharge a sheet fed from the transport unit; A sheet detecting unit for detecting the size of the sheet, a sheet discharging sensor for detecting an end of the sheet by the discharging unit, and a control unit for decelerating the sheet discharging roller based on a detection result of the size detecting unit. In the transport device, when the length of the sheet detected by the size detection unit is longer than a predetermined length, the control unit decelerates the discharge roller at a fixed position from the rear end of the sheet, When the length of the sheet is smaller than the predetermined length, the sheet discharge roller is decelerated at a fixed position from the leading end of the sheet. 2. A conveying section for conveying a sheet fed from a feeding section to a predetermined position, a discharge section having a discharge roller for discharging the sheet fed from the conveying section, and a length of the conveyed sheet. Size detecting means for detecting the end of the sheet, a discharge sensor for detecting the end of the sheet at the discharge section, and the discharge roller at a constant deceleration position from the rear end of the sheet based on the detection result of the size detecting means. Control means for decelerating, when the length of the sheet detected by the size detecting means is smaller than a predetermined length, the distance from the sheet trailing edge is constant. A sheet conveying device, wherein the discharge roller is decelerated at a deceleration position shorter than a deceleration position.