CN102030207A - Sheet conveying device, image forming apparatus, and method of detecting double-feed of sheet - Google Patents

Abstract

The present invention provides a sheet conveyance device, an image forming apparatus, and a sheet double-feed detection method capable of detecting double-feed in a state where a document is not bent, thereby improving the accuracy of double-feed detection. The sheet conveyance device of the present invention includes: a first roller for correcting the inclination of the conveyed sheet; Information on overlapping conveyance; a second roller that conveys the sheet to the first roller; a driving unit that drives the second roller; and a controller that controls the driving unit so that an end on the downstream side in the direction of conveyance of the sheet is located at a lower position than the first roller. In a state where the nip position of one of the rollers is closer to the upstream side in the sheet conveyance direction, the conveyance of the sheet is temporarily stopped so as to be detected by the first detection unit.

Description

Sheet conveying device, image forming device, and sheet overlapping conveying detection method

Cross References to Related Applications

This application claims priority to US Provisional Patent Application Serial No. 61/248910, filed October 6, 2009, the entire contents of which are hereby incorporated by reference.

technical field

The present invention relates to a technique for detecting overlapping conveyance of sheets.

Background technique

The prior art detects that the overlapping feeding of originals conveyed by the automatic original feeding device is carried out in a curved state after the originals are brought into contact with alignment rollers for correcting the skew of the originals.

However, since the positional relationship between the sensor for detecting multi-feed and the document is not stable, the detection of multi-feed cannot be performed stably.

Contents of the invention

In view of the above problems, the present invention provides a sheet conveyance device, an image forming apparatus, and a sheet double feed detection method capable of detecting double feed while the document is not bent, thereby improving the accuracy of double feed detection.

The sheet conveyance device of the present invention includes: a first roller for correcting the inclination of the conveyed sheet; Information on overlapping conveyance; a second roller that conveys the sheet to the first roller; a driving unit that drives the second roller; and a controller that controls the driving unit so that the end portion on the downstream side in the conveying direction of the sheet is located at a lower position than the second roller. In a state where the nip position of one roller is closer to the upstream side in the sheet conveying direction, the conveying of the sheet is temporarily stopped so as to be detected by the first detection unit.

An image forming apparatus according to the present invention includes: a document conveying unit including: a first roller for correcting the inclination of a conveyed document; and a first detection unit located closer to the first roller than the first roller. The upstream side of the document conveyance direction for detecting information on overlapping conveyance of original documents; the second roller for conveying the document to the above-mentioned first roller; and the drive section for driving the above-mentioned second roller; optically reading the document conveyed by the above-mentioned document conveyance unit a reading section; an image forming section that forms an image on a sheet based on the image data read by the reading section; In a state where the nip position of the rollers is closer to the upstream side in the document conveyance direction, the conveyance of the document is temporarily stopped so as to be detected by the first detection unit.

The method for detecting overlapped conveyance of sheets according to the present invention is characterized in that overlapping of sheets is detected in a state where the end portion on the downstream side in the conveyance direction of the sheet is located on the upstream side in the sheet conveyance direction than the nip position of the roller for correcting the skew of the sheet. delivery.

Description of drawings

FIG. 1 is a cross-sectional view of an image forming apparatus;

Fig. 2 is a sectional view of the automatic document feeding device;

3 is a block diagram of parts related to document feeding of the automatic document feeding device;

FIG. 4 is a flowchart showing the operation of the automatic document feeder;

5 is a cross-sectional view of the automatic document feeder schematically showing a document at a double-feed detection position;

6 is a cross-sectional view of the automatic document feeder schematically showing the position of the document when the motor drive unit is stopped.

Detailed ways

FIG. 1 is a cross-sectional view of an image forming apparatus. The image forming apparatus 1 may be an MFP (Multi Function Printer).

Referring to FIG. 1 , an image forming apparatus 1 includes an image reading portion R and an image forming portion P. As shown in FIG. The image reading unit R scans and reads sheet originals and book originals.

The image forming unit P forms a developer image on a sheet based on an image read from a document by the image reading unit R or print data transmitted from an external device to the image forming apparatus 1 .

The image reading unit R includes an automatic document feeder 9 (ADF (Automatic Document Feeder)) that automatically feeds a document to a designated image reading position. Images of documents placed on a document tray (designated document table) Rt automatically transported by the automatic document feeder 9 and documents placed on a document table (not shown) are read by the scanning optical system 10 .

Further, image forming unit P includes toner cartridges 1Y to 1K, photoreceptors 2Y to 2K, developing rollers 3Y to 3K, mixers 4Y to 4K, intermediate transfer belt 6 , fixing device 7 , and discharge tray 8 .

The image forming apparatus 1 of the present embodiment includes a controller 801 , a memory 803 , an operation display unit 805 , and a communication unit 807 .

Controller 801 has a role to execute various processes in image forming apparatus 1 , and also has a role to realize various functions by executing programs stored in memory 803 . The memory 803 may be, for example, RAM (Random Access Memory), ROM (Read Only Memory), DRAM (Dynamic Random Access Memory), SRAM (Static Random Access Memory), VRAM (Video Random Access Memory), and the like. The memory 803 has a role of storing various information and programs used in the image forming apparatus 1 .

Various settings are displayed on the operation display unit 805 . The operation display section 805 may be LCD (Liquid Crystal Display), EL (Electro Luminescence Display), PDP (Plasma Display), and CRT (Cathode Ray Tube Display)

Various settings can be changed by operating the operation display unit 805 . The operation display unit 805 may be a touch panel type.

Next, an outline of copy processing will be described as an example of processing in the image processing apparatus according to this embodiment.

First, a sheet picked up from a cassette enters the sheet conveying path. The plurality of roller pairs moves the sheet entering the sheet conveying path in a predetermined conveying direction.

Then, the images of the plurality of sheet originals continuously and automatically conveyed by the automatic document feeder 9 are read by the scanning optical system 10 at the designated image reading position.

Next, based on the print data of the image read by the image reading section R from the original document, it is used for transferring the developer images of yellow (Y), magenta (M), cyan (C) and black (K) to the sheet. Electrostatic latent images are formed on the photosensitive surfaces of the upper photoreceptors 2Y, 2M, 2C, and 2K.

Next, the developer stirred by the mixers 4Y to 4K of the developing device is attached to the above-mentioned photoreceptors 2Y to 2K on which the electrostatic latent images are formed by the developing rollers 3Y to 3K. In this way, the electrostatic latent image formed on the photosensitive surface of the photoreceptor is developed.

The developer image formed on the photoreceptor in this way is transferred onto the belt surface of the intermediate transfer belt 6 (so-called primary transfer), and the developer image conveyed by the rotation of the intermediate transfer belt 6 is transferred at a specified second time. onto the conveyed sheet at the secondary transfer position T.

The developer image transferred onto the sheet is heat-fixed on the sheet by the fuser 7 . The sheet on which the developer image is heat-fixed is conveyed along a conveyance path by a plurality of conveyance rollers, and is sequentially discharged to a discharge tray 8 .

Next, the automatic document feeder 9 will be described. 2 is an enlarged sectional view of the automatic document feeder. Documents are placed on a document tray 11 . Originals can be multiple or single.

A pickup roller 12 serving as a third roller picks up a document placed on the document tray 11 and conveys it to a paper feed roller 13 serving as a second roller. The paper feed roller 13 conveys the document picked up by the pickup roller 12 downstream in the conveyance direction.

The rotation shafts of the pickup roller 12 and the paper feed roller 13 are connected to each other through a transmission mechanism 18 . The transmission mechanism 18 may be a conveyor belt or a pulley.

FIG. 3 is a block diagram of components involved in document feeding of the automatic document feeder 9 . Referring to the figure, the pickup roller 12 moves up and down by the operation of the solenoid drive part 40 . The solenoid driving section 40 includes a solenoid driver 41 and a pickup solenoid 42 .

Referring to FIG. 2 , a separation roller 14 as a fourth roller is located opposite to the paper feed roller 13 . If the pickup roller 12 picks up two or more originals, due to friction between the originals, the load on the torque limiter of the separation roller 14 increases, and the separation roller 14 stops. The stopped separation roller 14 comes into contact with the lower sheet, and prevents the lower sheet from being conveyed downstream.

The registration roller 15 as a first roller abuts on the document conveyed by the paper feed roller 13 to correct the skew of the document. That is, the alignment roller 15 is composed of two rollers that are in contact with each other, and bends the document by contacting the nip formed by the contact of the two rollers, thereby correcting the inclination of the document.

Referring to FIG. 3 , the motor drive unit 30 drives the pickup roller 12 , the paper feed roller 13 and the registration roller 15 . The motor driving unit 30 includes a motor driver 31 and a document feeding motor 32 .

The document feeding motor 32 may be a stepping motor. The controller 801 outputs a pulse signal to the motor driver 31 . The motor driver 31 supplies a driving current to the document feeding motor 32 according to the received pulse signal.

The controller 801 controls the driving amount of the document feeding motor 32 by controlling the pulse number of the pulse signal output to the motor driver 31 .

The forward rotation of the document feeding motor 32 drives the pickup roller 12 and the paper feeding roller 13 to rotate. The reverse rotation of the document feeding motor 32 drives the registration roller 15 to rotate.

The level sensor 16 is located between the separating roller 14 and the leveling roller 15 . The level sensor 16 detects the arrival of the document conveyed by the separation roller 14 .

The overlapping conveyance detection unit 17 is located between the registration roller 15 and the registration sensor 16 . The overlapping conveyance detection unit 17 may be a non-contact sensor. The non-contact sensor may be an ultrasonic sensor.

When the overlapping feed detecting section 17 is an ultrasonic sensor, the overlapping feeding detecting section 17 includes an ultrasonic generating section 17 a and an ultrasonic receiving section 17 b. The ultrasonic generating unit 17a and the ultrasonic receiving unit 17b face each other across the conveyance path of the document. The ultrasonic generator 17a is located on the downstream side in the document conveyance direction relative to the ultrasonic receiver 17b. The ultrasonic wave generator 17a and the ultrasonic wave receiver 17b may face obliquely with respect to the conveyance path of the document. The detection accuracy can be improved by obliquely facing the ultrasonic generating part 17a and the ultrasonic receiving part 17b.

The ultrasonic wave output from the ultrasonic wave generator 17a is received by the ultrasonic wave receiver 17b. Ultrasonic waves entering the original are gradually attenuated. As the number of originals increases, the attenuation range increases. The ultrasonic receiving unit 17b outputs a corresponding signal to the controller 801 according to the received ultrasonic intensity.

When documents entering the detection position of the overlapping feed detection unit 17 are overlapped, the ultrasonic wave intensity received by the ultrasonic wave receiving unit 17b is weaker than the normal case, that is, when one document is detected. The controller 801 recognizes whether documents are overlapped or not based on the strength of the signal output from the ultrasonic receiver 17b.

The controller 801 controls the driving timing of the registration rollers 15 so that the document bent by contacting the registration rollers 15 is conveyed so as to match the toner image formed on the transfer belt 11 .

The operation of the automatic document feeder 9 will be described with reference to the flowchart of FIG. 4 . In Act 101 , the controller 801 moves the pickup roller 12 downward toward a pickup position for picking up a document placed on the document tray 11 by controlling the solenoid drive unit 40 .

In Act 102 , the controller 801 drives the pickup roller 12 and the paper feed roller 13 by controlling the motor drive unit 30 . The document picked up by the pickup roller 12 moves downstream. In Act 103 , the controller 801 judges whether the level sensor 16 has detected the document.

If the level sensor 16 has detected the document, go to Act 104 . In Act 104 , the controller 801 starts counting the number of pulses output to the motor driver 31 .

In Act105, the controller 801 judges whether the number of counted pulses has reached N1. If the number of pulses has reached N1, go to Act106.

The controller 801 stops the driving of the motor driving unit 30, and the conveyance of the document is stopped. The position at which document conveyance stops is the position at which double-feed detection is performed by the double-feed detection unit 17 .

When the controller 801 stops the motor drive unit 30 , the downstream end of the document in the conveyance direction is set to be located upstream in the conveyance direction relative to the nip portion of the registration roller 15 . 5 is a cross-sectional view of an automatic document feeder schematically showing a document at a double-feed detection position. Referring to the figure, the document stops before abutting against the registration rollers 15 and is in a state of following the transport path without bending.

When the document is conveyed by the pickup roller 12 and the paper feed roller 13, even if it slips, it has no effect on controlling the stop of the document. That is, since the detection result of the level sensor 16 located between the paper feed roller 13 and the registration roller 15 is used to control the stop of the document, instability of the detection position of the double feed is suppressed.

In Act 107, the controller 801 determines whether or not documents are overlapped based on the output signal of the ultrasonic receiver 17b. Since the document is positioned straight along the conveyance path without being bent, the accuracy of overlapping conveyance detection is improved.

If overlapping feeding of documents occurs, in Act 108 , the controller 801 displays a notification to the operation display unit 805 that overlapping feeding has occurred. If the document is not double fed, go to Act 109.

In Act 109, the controller 801 drives the motor drive unit 30 again to rotate the paper feed roller. In Act 110 , the controller 801 starts counting the number of pulses output to the motor driver 31 .

In Act 111, the controller 801 judges whether the counted number of pulses has reached N2. If the number of pulses has reached N2, the process proceeds to Act 112, and the controller 801 stops driving the motor drive unit 30 .

6 is a cross-sectional view of the automatic document feeder 9 schematically showing the position of the document when the motor drive unit 30 is stopped. Referring to the figure, the downstream conveyance of the document is hindered by contact with the registration rollers 15 , and the document is bent.

In Act 113, the controller 801 judges whether or not the scanning timing has come. The scanning timing refers to the timing at which the document is positioned at the reading position when the scanning optical system 10 starts scanning.

In Act 114 , the controller 801 controls the motor drive unit 30 to rotate the document feeding motor 32 in the reverse direction, and further rotates the registration roller 15 . The document is nipped by registration rollers 15 and moved to the image reading position. FIG. 6 omits the transport operation of the document from the registration roller 15 to the reading position.

(Modification 1)

As a method of stopping the document at the overlapping feed detection position, the controller 801 counts the number of pulses output to the motor driver 31 after detection by the level sensor 16 , or counts the driving time of the paper feed roller 13 . That is, the time for the paper feed roller 13 to rotate is measured, and when the measured time reaches a specified time, the controller 801 may stop the motor drive unit 30 . This specified time is calculated based on the rotational speed of the paper feed roller 13 . The calculated specified time is stored in the memory 803 in advance, and the controller 801 can read information on the specified time from the memory 803 to perform the above-mentioned control.

(Modification 2)

The overlapping conveyance detection unit 17 may be another non-contact sensor. Other non-contact sensors may be optical sensors. An optical sensor includes a light-emitting element and a light-receiving element. These light-emitting elements and light-receiving elements are located at the position where the original is held. The controller 801 recognizes the presence or absence of overlapping feed from the amount of light received by the light receiving element.

(Modification 3)

The document feeding motor 32 may be a DC motor. The output shaft of the DC motor is equipped with a photo interrupter. The controller 801 controls the driving amount of the DC motor by the number of times the optical interrupter interrupts the light.

(Modification 4)

Although the above-described embodiment has been described with respect to the automatic document feeder 9 that feeds a document toward a reading position, it is also applicable to a sheet feed system that feeds paper from a cassette tray or a manual feed tray. That is to say, the double feed detection may be performed by temporarily stopping sheet conveyance at a position upstream in the conveyance direction from registration rollers included in a sheet conveyance system that feeds sheets from a cassette tray or a manual feed tray.

Although some embodiments have been described, these embodiments are merely examples and are not intended to limit the scope of the present invention. In fact, the new methods and systems described herein can be embodied in other various ways, and various omissions, substitutions and changes of the methods and systems described herein are within the scope of the spirit of the present invention. The appended claims and their equivalents are intended to cover all manners and modifications commensurate with the scope and spirit of the invention.

Claims (20)

1. sheet-conveying device comprises:

First roller that the inclination of conveying thin slice is proofreaied and correct;

First test section, described first test section are positioned at than the more close thin slice throughput direction of described first roller upstream side, are used to detect the information of the overlapping conveying of relevant thin slice;

Carry second roller of thin slice to described first roller;

Drive the drive division of described second roller; And

Controller, by controlling described drive division, under the end of the conveyance direction downstream side of thin slice is positioned at state than the more close thin slice throughput direction of the clip position of described first roller upstream side, thin slice is carried temporarily stopped, so that detect by described first test section.

2. sheet-conveying device according to claim 1, wherein,

Comprise between described second roller and described first test section and be used to detect second test section that thin slice enters,

If described second test section detects thin slice and enters, then described controller begins control, makes thin slice be parked in the detection position of described first test section.

3. sheet-conveying device according to claim 2, wherein,

Described drive division comprises the actuator of pulse motor and described pulse motor,

If described second test section detects thin slice and enters, then described controller begins to count the pulse count to described actuator output, and according to this count results, thin slice is stopped on the detection position of described first test section.

4. sheet-conveying device according to claim 1, wherein,

Described first test section is the test section of non-contact type.

5. sheet-conveying device according to claim 4, wherein,

Described first test section comprises:

Produce hypracoustic super sonic generating unit; And

Receive the hypracoustic super sonic acceptance division that described super sonic generating unit produces,

Described super sonic generating unit and described super sonic acceptance division are relative across the thin slice transport path.

6. sheet-conveying device according to claim 5, wherein,

Described super sonic happening part is in the position than the more close thin slice throughput direction of described super sonic acceptance division downstream.

7. sheet-conveying device according to claim 2, wherein,

Described second test section is positioned at thin slice transport path below.

8. sheet-conveying device according to claim 1, wherein,

Comprise the 3rd roller that picks up thin slice to described second roller,

Described second roller and described the 3rd roller connect by transmission device.

9. sheet-conveying device according to claim 8, wherein,

Described second roller is relative with the 4th roller, the overlapping conveying of the thin slice that described the 4th roller is used to forbid that described the 3rd roller picks up.

10. image processing system comprises:

The original copy delivery section, described original copy delivery section comprises:

First roller that the inclination of the original copy carried is proofreaied and correct;

First test section, described first test section are positioned at than the more close original copy throughput direction of described first roller upstream side, are used to detect the information of the overlapping conveying of relevant original copy;

Carry second roller of original copy to described first roller; And

Drive the drive division of described second roller;

The original copy that described original copy delivery section is carried carries out optically read reading part;

The view data that reads according to described reading part forms the image forming part of image on thin slice; And

Controller, by controlling described drive division, under the end of the conveyance direction downstream side of original copy is positioned at state than the more close original copy throughput direction of the clip position of described first roller upstream side, original copy is carried temporarily stopped, so that detect by described first test section.

11. image processing system according to claim 10, wherein,

Described original copy delivery section comprises between described second roller and described first test section and is used to detect second test section that original copy enters,

If described second test section detects original copy and enters, then described controller begins control, makes original copy be parked in the detection position of described first test section.

12. image processing system according to claim 11, wherein,

Described drive division comprises the actuator of pulse motor and described pulse motor,

If described second test section detects original copy and enters, then described controller begins to count the pulse count to described actuator output, and according to this count results, original copy is stopped on the detection position of described first test section.

13. image processing system according to claim 10, wherein,

Described first test section is the test section of non-contact type.

14. image processing system according to claim 13, wherein,

Described first test section comprises: produce hypracoustic super sonic generating unit; And the hypracoustic super sonic acceptance division that receives described super sonic generating unit generation,

Described super sonic generating unit and described super sonic acceptance division are relative across the original copy transport path.

15. image processing system according to claim 14, wherein,

Described super sonic happening part is in the position than the more close original copy throughput direction of described super sonic acceptance division downstream.

16. image processing system according to claim 11, wherein,

Described second test section is below the original copy transport path.

17. image processing system according to claim 10, wherein,

Described original copy delivery section comprises the 3rd roller that picks up original copy to described second roller,

Described second roller and described the 3rd roller connect by transmission device.

18. image processing system according to claim 17, wherein,

Described second roller is relative with the 4th roller, the overlapping conveying of the original copy that described the 4th roller is used to forbid that described the 3rd roller picks up.

19. the overlapping conveying method of inspection of a thin slice, wherein,

Under the end of the conveyance direction downstream side of thin slice is positioned at state than the more close thin slice throughput direction of the clip position upstream side that is used to proofread and correct thin slice bevelled roller, detect the overlapping conveying of thin slice.

20. the overlapping conveying method of inspection of thin slice according to claim 19, wherein,

Described overlapping conveying detects uses non-contact sensor to carry out.

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