JP2849909B2 - Automatic document 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 paper feeding means for feeding a document on a paper feed tray onto a platen of an image forming apparatus,
Transport means for transporting the document fed on the platen in the direction of the platen downstream by the transport belt; anddocument discharge means for discharging the exposed document discharged on the platen to a discharge tray, The exposed first document is conveyed to the downstream side of the platen, the second document is fed onto the platen and stopped at the exposure position, and the third document is fed to the feed tray during the exposure of the second document. The present invention relates to an automatic document feeder configured to feed a document to a standby position between the document and a platen.

[0002]

2. Description of the Related Art In recent years, an image forming apparatus such as a copying apparatus has been required to process a large number of originals at a high speed. For this purpose, it is natural that the operation speed of the main part is increased, and the interval between the fed originals is reduced as much as possible, and at the same time as the localization of the next original or the exposure of the next original. During operation, a process of discharging a preceding document is performed, and a document to be fed one after another is heeled to the upstream side of the next document to be made to work.

An automatic document feeder having such a so-called continuous feed mode is disclosed in, for example, Japanese Patent Application Laid-Open No. 1-2361.
There is one disclosed in Japanese Patent Publication No. 37-37.

According to the above publication, the transport section and the document discharge section are configured to be driven by separate drive sources, respectively, and in the continuous feed mode, when the next document is located upstream of the platen. At the same time, the preceding document is also subjected to a discharging operation from the downstream side on the platen, and the document sent one after another enters the state of the samurai machine on the upstream side outside the platen.

[0005] With such a configuration and operation, the original is fed onto the platen without loss of time regardless of the original size.

[0006]

However, in the above-described conventional configuration, when the original is pulled out from the downstream side on the platen and the discharge operation is performed while the original is localized on the upstream side on the platen, The transport belt is pulled due to the frictional force of the preceding document on the transport belt,
As a result, there is a serious problem that a document on the platen is displaced.

The present invention has been made in view of such a problem in the prior art, and does not give an unexpected movement to a conveyance belt when a preceding document is pulled out from a platen of an image forming apparatus. It is another object of the present invention to provide an automatic document feeder in which a document located on the upstream side of a platen does not have a positional shift and does not shake during image formation.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the gist of the present invention is to provide a paper feeding means for feeding a document on a paper feeding tray onto a platen of an image forming apparatus; A transport unit for transporting the fed document in a direction downstream of the platen by a transport belt; and a document discharging unit for discharging the exposed document discharged on the platen to a discharge tray. The second original is fed to the platen downstream side while the second original is fed onto the platen and stopped at the exposure position. During the exposure of the second original, the third original is fed to the feed tray and the platen. In the automatic document feeder in which the paper feeding means and the transporting means are controlled so as to feed the paper to a standby position, a braking means for applying a braking force to the transporting means, and the braking means, Is located at the exposure position. And control means for controlling the document discharge means to release the first document from the platen during the operation of the braking means, while releasing the second document after the exposure of the second document is completed. And an automatic document feeder.

In the automatic document feeder, when the second document is fed, the preceding first document is located on the downstream side of the platen of the image forming apparatus, and the second document is located at the predetermined reference position on the upstream side. (Exposed position), and the third document is sent upstream (standby position) outside the platen.

Subsequently, the first document is pulled out from the downstream side on the platen by the document discharge means. At this time, at the same time, the second
Is exposed to the original.

[0011] Thus, at the same time when the second document is localized at the predetermined exposure position, the braking means operates and the transport belt is stopped, so that the transport belt does not swing even though the first document is pulled out. Therefore, there is no occurrence of a document displacement or a flow of an image caused by a displacement during exposure.

When the exposure operation for the second document is completed,
In response to this end signal, the belt is released from being stopped by the braking means, and then the third document waiting on the upstream side outside the platen is sent to the platen, and the second document is placed on the downstream side on the same platen. And the above operation is repeated.

[0013]

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

In this embodiment, as shown in FIG. 1, an automatic document feeder 10 mounted on a platen P of an electronic copying apparatus C as an image forming apparatus and for sending a document to the platen P will be described.

This automatic document feeder includes a conveying means comprising a pair of belt rollers with a conveying belt stretched thereon, and a document discharging means which is driven independently of the conveying means. Automatic document feed compatible with continuous feed mode in which the document is sent onto the platen of the image forming apparatus while maintaining the interval, the preceding document is placed downstream of the platen, and the next document located on the upstream side of the platen is exposed. Device
After the next document is localized on the platen, when the preceding document sent to the downstream side of the platen is subsequently discharged, the conveyance device should be used as a braking means for preventing the movement of the conveyance belt. It is characterized in that the belt stopping means is provided, and that the belt stopping means is operated during the exposure operation of the image forming apparatus.

In the continuous feed mode, each document is sent in contact with the document at a predetermined minimum interval according to the size information of the fed document, and when the second document is fed,
The preceding first document is located downstream on the platen of the image forming apparatus, the second document is also located at a predetermined reference position on the upstream side, and the third document is located upstream outside the platen.
Subsequently, the first document is pulled out from the upstream and downstream sides of the platen by the document discharging means. At this time, the image forming apparatus simultaneously performs an exposure operation on the second document.

As a result, at the same time when the second document is localized at the predetermined exposure position, the belt restraining means operates and the transport belt is restrained, so that the transport belt does not swing even though the first document is pulled out. . Therefore, misalignment of the original,
There is no image flow or the like caused by a displacement during exposure.

When the exposure operation for the second document is completed,
In response to the end signal, the belt restraining means is released from the belt restraining means. Subsequently, the third document waiting on the upstream side outside the platen is sent to the platen, and the second document is placed on the same platen. And the above operation is repeated.

1 to 3 (b) show a first embodiment of the present invention.

As shown in FIG. 1, the automatic document feeder 10 includes a paper feed tray 11 on which a document is placed,
A sheet feeding unit 20 serving as a sheet feeding unit that separates the document from the sheet feeding unit 1 into a single sheet and feeds the document onto the platen P of the electronic copying apparatus C. The transport unit 30 as a transport unit that transports and localizes on the platen P of the copying apparatus C to perform an exposure process, a discharge unit 40 as a document discharge unit that discharges an exposed document, and a discharge unit that collects the discharged documents. It comprises a paper tray 12 and a control device (not shown).

The paper feed section 20 is driven by a drive motor M
T 1, the transport unit 30 is driven by a drive motor MT 2, and the discharge unit 40 is driven by a drive motor MT 3 and an individual drive source.

The paper feed unit 20 includes a pickup roller 21 which feeds out the sheet in contact with the lowermost sheet, a weight leaf spring 23 which presses in contact with the uppermost sheet, a stopper 22 which presses the leading edge of the document and opens and closes in a timely manner, and separates only the lowermost sheet. Roller 24, the separation pad 25 for preventing the second sheet or more from advancing, the registration rollers 26 and 27 for catching the leading edge of the document, adjusting the posture and feeding timing, and the size of the document to be fed. It is composed of a paper feed sensor 28 for detecting and the like. further,
Downstream of the registration rollers 26 and 27, a paper feed guide 29 that guides the leading end of the document to immediately before the transport unit 30 is provided.

The discharge unit 40 includes a discharge roller 42 for feeding a document.
A discharge guide 41 for guiding the document, a switching claw 43 for switching between discharging the document or reversely feeding the platen P again to expose the back surface, a reverse feeding guide 44 for guiding the reversely fed document, and a discharge guide It comprises a paper sensor 45 and the like.

As shown in FIG. 1, the transport section 30 includes a pair of belt rollers 32, 3 on a side plate 31 of the automatic document feeder 10.
3 is supported, a transport belt 34 is stretched over these belt rollers 32 and 33, and a plurality of press rollers 35 are provided. As shown in FIG. 1, a belt stopping means 36 as a braking means for applying a braking force to the transporting means 30 in order to prevent the transport belt 34 from being accidentally moved as shown in FIG. Are arranged.

As shown in FIG. 2, the belt stopping means 36 presses the conveying belt 34 against the upper surface of the platen P of the copying machine C to stop the conveying belt 34, and normally separates the stopping claw 39 from the conveying belt 34. It comprises a spring 38 to be held, and a solenoid 37 which is energized by a signal given at an appropriate time and operates the stopping claw 39.

Control devices (not shown) include input signals from the paper feed sensor 28 and the like, output signals to the drive motors MT1 to MT3, the belt stopping means 36, and the like, feeding and discharging signals from the copier C, mode signals, and the like. It has an input / output processing function and a size check counter for detecting the size of the original document based on a signal from the paper feed sensor 28. In addition to the normal individual copy mode from the copier C and the duplex copy mode, In the continuous feed mode in which the original is detected and the original is step-feeded.

Next, the operation will be described.

Since the paper feeding operation during normal one-sided or two-sided copying is well known, the description of the operation is omitted.

In the continuous feed mode, the first separated first sheet
The document D1 is detected by the paper feed sensor 28 before the registration rollers 26 and 27, delivered from the paper feed unit 20 to the transport unit 30, and stopped with its rear end aligned with the stop reference position (exposure position) P1 of the platen P. I do. During this time, the control device stores the size of the first document D1. Then, in response to an exposure processing request from the control device, exposure by the copying device C and a series of copying operations are performed.

During the above operation, the second original D
After the document D2 is fed and the posture is adjusted by the registration rollers 26 and 27, the paper end of the original D2 is
9 to the tip of the ninth, and a samurai machine immediately before the stop reference position P1. (See FIG. 3 (a).) In response to the exposure processing completion signal for the first document D1, the transport unit 3
The 0 drive motor MT2 is started, and the first document D1 is sent downstream on the platen P. At the same time, the drive motor MT1 of the paper supply unit 20 is also started, the second document D2 is fed to a predetermined position, and the separating operation of the third document D3 and the feeding operation to the paper feed guide 29 are performed. .

On the other hand, in the above operation, if the size of the first document D1 is smaller than the predetermined size, the first document D1 is stopped on the platen P together with the second document D2, and the third document D1 is stopped.
As the sheet 3 is sent onto the platen P, the discharging operation is performed. When the size is larger than a predetermined size, the leading end of the document D1 is detected by the sheet discharging sensor 45 as shown in FIG. The drive motor MT3 is started immediately by the signal, and the discharge roller 42 executes a discharge operation of the first document D1.

The belt stopping means 36 as the braking means
Is activated at the same time when the second document is localized at the exposure position, so that the solenoid 37 of the belt stopping means 36 is excited,
The stopper 39 presses the conveyor belt 34 onto the platen P. The operation of the belt stopping means 36 continues until it is released at the end of the exposure of the second document. For this reason, despite the discharging operation of the first document D1, the transport belt 34 is restrained by the belt restraining means 36 and does not shake. Processing is performed.

Next, a second embodiment of the present invention will be described with reference to FIG.

In this embodiment, a belt stopping means 50 as a braking means includes a cam member 52 oscillated by a solenoid 51, a belt pressing member 53 driven by the cam member 52 and pressing the transport belt 34, and a belt pressing member 53 And a spring 54 for urging the upper portion 53 upward. Further, the belt pressing member 53 includes a handle 53a,
It consists of a wide pressing portion 53b and a friction material 53c such as rubber.

According to the present embodiment, the pressing portion 53b of the pressing member 53 has a large contact area and can widely press the rear surface of the conveyor belt 34, so that the effect of stopping the belt can be more effectively exerted. The original under exposure on the lower surface can also be widely pressed at the same time, which is more effective.

Next, a third embodiment of the present invention will be described with reference to FIG.

In the present embodiment, a belt stopping means 55 as a braking means includes a solenoid 56 which operates in a timely manner, a gripping arm 57 which is opened / closed by the solenoid 56, and a gripping piece 58 attached to the tip end of the gripping arm 57. , 5
Consists of eight.

In the present embodiment, the front and back sides are securely gripped by the gripping pieces 58 having frictional force, instead of pressing one surface of the conveyor belt 34 onto a smooth platen, so that a more reliable stopping effect can be obtained. it can.

[0039]

According to the automatic document feeder according to the present invention, the automatic document feeder includes a paper feeding means, a conveying means, and a document discharging means, and conveys the exposed first document to the downstream side of the platen and the second document. An automatic document feeder, which feeds a third document to a platen and stops at an exposure position, and feeds a third document to a standby position between the feed tray and the platen during exposure of the second document. A braking means for applying a braking force to the transport means; operating the braking means at the same time when the second document is localized at the exposure position; releasing the braking means after the exposure of the second document is completed; The first document is forcibly discharged from the platen by operating the document discharging means during the operation of the means, so that when the preceding document is pulled out from the platen of the image forming apparatus, the movement of the transport belt is restricted. Blocked No positional deviation in the document that is localized at the upstream side of the down, shake during image formation does not occur.

[0040]

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of an automatic document feeder according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a configuration of a belt stopping unit as a braking unit according to the first embodiment of the present invention.

FIGS. 3A and 3B show the automatic document feeder according to the first embodiment of the present invention, and FIGS.

FIG. 4 is an explanatory diagram of a configuration of a belt stopping unit as a braking unit according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram of a configuration of a belt stopping unit as a braking unit according to a third embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 automatic document feeder 11 paper feed tray 12 paper discharge tray 20 paper feed unit (paper feed unit) 28 paper feed sensor 29 paper feed guide 30 transport unit (transport unit) 31 device side plate 32 belt roller 33 belt roller 34 transport belt 36 Belt stopping means (first embodiment) 37 solenoid 38 spring 39 stopping claw 40 discharging unit (document discharging means) 42 discharging roller 45 discharging sensor 50 belt stopping means (second embodiment) 51 solenoid 52 cam member 53 belt pressing member 54 Spring 55 Belt stopping means (third embodiment) 56 Solenoid 57 Gripping arm 58 Gripping piece P Platen P1 Stop reference position D1 First document D2 Second document D3 Third document

Claims (1)

(57) [Claims] A sheet feeding means for feeding a document on a sheet feeding tray onto a platen of the image forming apparatus; and a conveying means for conveying the document fed on the platen in a direction downstream of the platen by a conveying belt. A document discharging means for discharging the exposed document discharged on the platen onto a paper discharge tray, conveying the exposed first document downstream of the platen, and transferring the second document on the platen. The sheet feeding means and the conveying means are controlled so that the sheet is stopped at the exposure position and the third document is sent to the standby position between the sheet feeding tray and the platen during the exposure of the second document. In the automatic document feeder, a braking means for applying a braking force to the conveying means, and the braking means are activated at the same time when the second document is located at the exposure position, and the exposure of the second document is completed. Release later, Automatic document feeder, characterized in that provided and control means for controlling the document discharge means so as to forcibly discharge the first original during operation of the braking means from the platen, the.