JP2003263076A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device which performs an image forming operation by smoothly feeding a sheet without stopping the transport of the sheet even in a case where an overlapped transport takes place. <P>SOLUTION: A main control part 42 prepares data for an image to be output, and starts to feed a sheet. when the sheet reaches a registration gate 18, an overlap transport detection means 16 measures the thickness of a sheet. The main control part 42 fetches the measurement value from the overlapped transport detection means 16 and compares it with a predetermined value in order to judge that an overlapped transport has taken place or not. In a case where an overlapped transport has taken place, an image output part 26 is instructed to cancel the output of the prepared image and to output blank paper. Then, the data of the cancelled image is re-prepared. When the leading ends of overlappingly transported sheets are detected by a sheet detection sensor 32A, a transport path switching means 22 is operated to switch to a saving path, thereby saving the overlappingly transported sheets to a sheet storage part 28. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus provided with a mechanism for ejecting conveyed sheets (double-fed sheets) in a double-fed state.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer that forms an image on a sheet cut into a predetermined size, a large number of sheets set in a paper feed tray are conveyed one by one. , Form an image on the paper. At this time, if a double feed occurs in which two or more sheets of paper are overlapped, a paper jam occurs due to the double feed, and a blank sheet is mixed into the output paper after image formation. Cause

Therefore, in such an apparatus, a double feed detecting means for detecting the double feed of the sheets is provided, and when the occurrence of the double feed is detected, the apparatus is stopped and an alarm is displayed to inform the operator of the double feed. Is designed to be removed. Therefore, there is a problem that the apparatus cannot be operated until the double-fed sheet is removed, and the image forming work is interrupted.

Japanese Unexamined Patent Publication (Kokai) No. 4-85228 discloses a printing apparatus which separates a double-fed sheet by a separating means composed of a pair of rollers that roll at different peripheral speeds and sends the separated sheets to a printing section in order. Have been described. In this device, even if a double feed occurs, the double feed state that has occurred can be eliminated, so that it is not necessary to stop the device to remove the double feed paper, and the use efficiency of the device is improved.

[0005]

However, in the printing apparatus disclosed in Japanese Unexamined Patent Publication No. 4-85228, after the multi-feed paper is separated, printing is performed at the same timing as when the multi-feed does not occur on the separated paper. However, there is a problem in that the paper conveyance control becomes complicated. In particular, if the transport path from the paper feed tray to the separating means is long, there may be multiple sheets in the transport path, and the transport of subsequent sheets must be stopped while separating the multi-fed sheets. If so, paper collision will occur. There is also a problem in that when the multi-fed paper is separated, problems such as scratches and stains occur on the paper.

The present invention has been made in view of the above circumstances, and an object of the present invention is to smoothly feed a sheet without stopping the conveyance of the sheet even when a double feed occurs, and an image forming operation is performed. An object of the present invention is to provide an image forming apparatus capable of performing the above. Another object of the present invention is to provide an image forming apparatus capable of forming an image on a sheet having no defect.

[0007]

In order to achieve the above object, the image forming apparatus of the present invention, based on the prepared image data, a paper feeding means for continuously feeding the loaded papers. An image forming unit that forms and sends an image for each sheet fed from the sheet feeding unit, a double feed detecting unit that detects a double feed of the sheets, and a double feed when the double feed is detected. The image is formed so that the image formation on the sheet in the state is stopped and the image is transmitted, and the image is formed based on the image data prepared for the sheet that is next fed and the double feeding is not detected. It is characterized in that it comprises a control means for controlling the forming means, and a discharging means for discharging the double-fed paper fed from the image forming means.

In this image forming apparatus, when the papers loaded in the paper feeding means are continuously fed, the image forming means, based on the prepared image data, feeds the papers fed from the paper feeding means. An image is formed for each sheet. At this time, if the double-feed detection unit detects the double-feed of the sheets, the formation of the image on the sheet in the double-feed state is stopped, and the next fed sheet, in which the double-feed is not detected, is prepared. The image forming means is controlled so as to form an image based on the obtained image data. Then, the sheet in the multi-feed state sent from the image forming means is discharged by the discharging means.

In this way, the image forming means is controlled to form an image that should have been formed on the sheet in the double-feed state, on the sheet fed in the normal state without the next double-feed. Therefore, even when double feeding occurs, it is possible to smoothly feed the sheet and perform the image forming operation without stopping the conveyance of the sheet. Further, since the image is not formed on the sheet in the double-feed state, it is possible to form the image on the sheet having no problem.

The above-mentioned discharging means may be a retracting mechanism for retracting the sheets in the double feeding state to a path different from the discharging path, and the sheet in the double feeding state may be different from a normal discharge tray. It may be a discharge tray changing mechanism that discharges the sheet.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments in which the present invention is applied to a copying machine will be described below in detail with reference to the drawings.
As shown in FIG. 1, the copying machine according to the present embodiment includes an apparatus main body 10 and a paper discharge unit 12 attached to a side surface of the apparatus main body 10. Device body 10
Includes a paper feeding unit 14 that feeds paper to the feeding path. On the downstream side of the paper feeding unit 14 in the feeding direction, a double feeding detection unit 16 that detects the double feeding of the paper, and the paper is temporarily stopped and fed. A registration gate 18 that adjusts the timing, an image forming unit 20 that forms an image on a sheet that is supplied based on input image data, and a transport path switching unit 22 that switches the transport path of the sheet are arranged in this order along the transport path. It is arranged.

The paper supply unit 14 includes a plurality of paper feed trays 14.
A, 14B, and 14C are provided, and paper according to a designated size is supplied from any of the paper feed trays. The paper double-feed detection unit 16 is composed of a paper thickness detection sensor that detects the thickness of the paper supplied from the paper supply unit 14, and detects the thickness of the paper stopped by the registration gate 18.

The image forming section 20 includes a photosensitive drum 24 and an image output section 26. The image output unit 26 is a light source such as a semiconductor laser, a polygon mirror for deflecting the laser light emitted from the light source toward the photoconductor drum 24, and f
Laser ROS (raster optical scann) including θ lens
er).

Further, around the photoconductor drum 24, a charging device, a developing device, a transfer device, a fixing device and the like (not shown) are arranged, and the photoconductor drum 24 which rotates at a constant speed in the direction of arrow A is driven by the charging device. When uniformly charged, the surface of the charged photosensitive drum 24 is scanned and exposed by the light beam modulated by the image output unit 26 according to the image data of the output image, and an electrostatic latent image is formed. This electrostatic latent image is developed with toner by a developing device, transferred onto a sheet supplied by a transfer device, and fixed on the sheet by a fixing device. As a result, an image is formed on the paper.

Further, the apparatus main body 10 has a sheet storage section 28 for temporarily storing the double-fed sheets removed from the normal conveyance path.
The transport path switching unit 22 selectively switches between a discharge path for discharging a sheet on which an image is formed to the paper discharge section 12 and a retract path for retracting a double-fed sheet to the paper storage section 28. A paper detection sensor 32A for detecting the paper reaching the branch point is provided near the branch point between the discharge path and the retreat path, and a retreat path is provided between the transport path switching means 22 and the paper storage section 28. A paper detection sensor 32B for detecting the invading paper is provided. Further, a large number of sheet conveying roller pairs 30 are arranged along the sheet conveying path including the discharge path and the retreat path. It should be noted that FIG. 1 illustrates some of the sheet conveying rollers.

An operation panel 34 as a user interface (UI) is provided on the outer upper surface of the apparatus body 10. The operation panel 34 is composed of a display section and operation keys, and the user operates the operation keys according to the operation menu displayed on the display section to input output conditions such as mode setting, paper size, and the number of copies.

The paper discharge unit 12 is provided with a discharge tray 36 for discharging the paper on which the image is formed and purge trays 38A, 38B for discharging unnecessary paper such as double-fed paper. A first discharge tray switching means 40A for switching the tray to the purge tray 38A is provided at the branch point between the discharge tray 36 and the purge tray 38A, and a branch point between the purge tray 38A and the purge tray 38B is provided at the branch point.
A second discharge tray switching means 40B for switching the tray to the purge tray 38B is provided.

As shown in FIG. 2, the apparatus main body 10 is provided with a main body control section 42 and a memory 44 for controlling the entire apparatus main body, and the double feed detecting means 16 explained above,
Registration gate 18, transport path switching means 22, image output unit 2
6, sheet conveying roller group 30, sheet sensors 32A, 32
Each of B and the operation panel 34 has a main body control unit 42.
It is connected to the. On the other hand, the paper discharge unit 12 includes a discharge control unit 46 connected to the main body control unit 42, and
The respective discharge tray switching means 40A and the second discharge tray switching means 40B are controlled by the discharge control section 46.

Next, the control routine of the main body control section 42 of the copying machine will be described. In this copying machine, the processing method in the case where double feed occurs by the operator is preset. When the operator operates the operation panel 34 to instruct the start of the copying operation, as shown in FIG.
At 00, it is determined whether or not the set processing method is a method for discharging the double-fed sheet to the tray. If it is determined that the tray is not set to eject, step 1
When it is determined that the evacuation process is started in 02 and the tray is set to be ejected, the tray ejection process is started in step 104.

First, the save processing subroutine will be described. When this subroutine is started, as shown in FIG. 4, image data to be output in step 200 is prepared,
In step 202, the paper feed roller 30 is driven to start feeding. Next, at step 204, cash register 1
Based on the detection signal from 8, it is determined whether or not the paper has reached the registration gate 18. The sheet that has reached the registration gate 18 is temporarily stopped from being conveyed.

At this time, since the sheet is stopped at the measuring position of the double feed detecting means 16, the thickness of the sheet conveyed by the double feed detecting means 16 is measured. Therefore, if it is determined that the paper has reached the registration gate 18, it is determined in step 206 whether the double feed has occurred by taking in the measured value of the paper thickness from the double feed detection means 16 and comparing it with the specified value in step 208. Determine whether or not. That is, the specified value of the paper thickness is set in advance, and by reading the specified value set from the memory 44 and comparing the measured value of the paper thickness with the specified value, it is determined whether a double feed has occurred. Determine whether or not.

If it is determined in step 208 that a double feed has occurred, then in step 210, the fact that it is a double feed paper (abnormal paper) is added to the print information of the paper (double feed paper) in the double feed state and the memory is added. In step S212, the image output unit 26 is caused to stop outputting the image prepared in step S200. Next, at step 214, the registration gate 18 is opened at a predetermined timing to restart the sheet conveyance. Since the conveyed multi-fed paper reaches the image forming unit 20 at the same timing as the normal paper, the image output unit 26 in step 216.
To output a blank image. That is, no image is formed on the multi-fed paper. Then, in step 218, the data of the image whose output is stopped is prepared again.

Next, at step 220, when the leading edge of the multi-fed paper is detected by the paper detection sensor 32A provided at the branch point between the discharge path and the retreat path, the transfer path switching means 2
2 is operated to switch the transport path to the retract path, and the double-fed sheet is retracted to the sheet storage unit 28. When the sheet detection sensor 32A detects the trailing edge of the double-fed sheet, the transport path switching unit 22 is operated to switch the transport path to the discharge path side. The conveyance route may be switched to the retreat route immediately after determining that the double feed has occurred, without detecting the leading edge of the double feed sheet.

The retracted double-fed sheet is temporarily stored in the sheet storage section 28 until the operator removes it.
After that, the process returns to step 202, the supply of the next paper is started at a predetermined timing, and the procedure from step 203 to step 220 is repeated until an image of which output is stopped is formed on the paper which is not in the multi-feed state.

On the other hand, if it is determined in step 208 that no double feed has occurred, then in step 222 the registration gate 18
Is opened at a predetermined timing to restart the sheet conveyance.
As a result, the conveyed sheet reaches the image forming section 20, and the image output section 26 is made to output the prepared image in step 224. When the image output is completed, step 22
In step 6, it is determined whether or not the copying is completed. If not completed, the supply of the next sheet is started at a predetermined timing in step 228, the data of the image to be output next is prepared in step 230, and the process returns to step 202.

If the copying is completed, step 2
At 32, the print information recorded for each sheet in the memory 44 is read out, and at step 234, it is judged from the print information whether or not the double feed is detected. If it is determined in step 234 that double feed has been detected, the occurrence of double feed is displayed on the operation panel 34 in step 236, and the subroutine ends. Since the operator can know the occurrence of the double feed from the display of the operation panel 34, the double feed paper stored in the paper storage unit 28 can be removed. On the other hand, step 23
The subroutine is also ended when it is determined that the double feed is not detected in 4.

Next, the subroutine of the tray discharging process will be described. When this subroutine is started, FIG.
As shown in, the image data to be output in step 200 is prepared. Steps 200 to 218 and steps 222 to 230 are the same as in the case of the saving process, and therefore only different points will be described, and the same parts will be denoted by the same reference numerals and description thereof will be omitted.

In this subroutine, after the data of the image whose output is stopped is prepared again in step 218, the print information is read from the memory 44 in step 300,
It is transmitted to the discharge control unit 46 of the paper discharge unit 12. Since the transport path switching means 22 is not in operation, the double-fed paper advances through the discharge path and is sent to the paper discharge unit 12. Then, after transmitting the print information, the process returns to step 202, and the procedure from step 203 to step 220 is repeated until the output-stopped image is formed on the sheet that is not in the multi-feed state. Further, even after the data of the next output image is prepared in step 230, the print information is transmitted to the ejection control unit 46 in step 302, and the process returns to step 202.

As shown in FIG. 6, when the discharge controller 46 receives the print information in step 400, the discharge controller 46 proceeds to step 4
In step 02, it is determined from the print information whether or not the next sheet sent to the sheet discharge unit 12 is a double-fed sheet. If it is determined in step 402 that the paper is double-fed paper, step 4
In 04, the first discharge tray switching means 40A is operated to switch the tray to the purge tray 38A, and the double-fed sheet is discharged to the purge tray 38A. In step 406, the control section 42 of the apparatus main body is notified of the discharge of the double-fed sheet. Exit the routine. Further, it is also possible to operate the second discharge tray switching means 40B to switch the tray to the purge tray 38B and discharge the double-fed paper to the purge tray 38B. on the other hand,
If it is determined in step 402 that the sheet is not a double-fed sheet, in step 408 the first discharge tray switching unit 40A
The sheet is discharged to the discharge tray 36 and the routine is ended without operating.

As described above, in the copying machine according to the present embodiment, the image that should have been formed on the sheet in the multi-feed state is formed on the next sheet that is not in the multi-feed state. Even when a double feed occurs, it is not necessary to stop the conveyance of the sheet, and the sheet can be smoothly fed at a predetermined timing. As the copy work is not interrupted like this,
Copier productivity is improved. Further, since no image is formed on the double-fed paper, a defective print is not created.

[0031]

According to the image forming apparatus of the present invention, even when a double feed occurs, it is possible to smoothly feed the paper and perform the image forming work without stopping the conveyance of the paper. . Further, the image forming apparatus of the present invention has an effect of being able to form an image on a sheet having no defect.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a schematic configuration of a copying machine according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a copying machine according to an embodiment of the present invention.

FIG. 3 is a flowchart showing a control routine of the copying machine according to the embodiment of the present invention.

FIG. 4 is a flowchart showing a subroutine of save processing.

FIG. 5 is a flowchart showing a tray discharge processing subroutine.

FIG. 6 is a flowchart showing a processing routine in the discharge control unit.

[Explanation of symbols]

10 Device body 12 Paper output section 14 Paper supply section 16 Double feed detection means 18 cash register 20 Image forming unit 22 Transport route switching means 24 photoconductor drum 26 Image output section 28 Paper Storage Unit 30 Paper transport roller pair 34 Operation panel 36 Ejection tray 38A, 38B Purge tray 40A First discharge tray switching means 40A 40B Second discharge tray switching means 40B 42 Main unit controller 44 memory 46 Emission control unit

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/00 530 G03G 15/00 530 F term (reference) 2C061 AP04 AQ06 HH03 HJ04 HV09 HV46 2H027 DC02 DC16 ED17 ED19 EK03 EK10 FA27 GB06 2H072 AA04 AA07 AA13 AA22 CB01 EA14 JA04 3F048 AA01 AB01 BA13 BB03 CA02 CC02 DA06 DC00 EB28 3F053 EA02 EA05 ED18 ED25 LA02 LA07 LB03

Claims (3)

[Claims] 1. A paper feeding unit for continuously feeding loaded paper sheets, and an image is formed and sent out for each sheet fed from the paper feeding unit based on prepared image data. Image forming means, a double feed detecting means for detecting the double feeding of the paper, and when the double feeding is detected, the formation of the image on the paper in the double feeding state is stopped and the next feeding is performed. Control means for controlling the image forming means so as to form an image on the basis of image data prepared for a sheet that has been fed and for which double feeding has not been detected; and a double feeding state sent from the image forming means. An image forming apparatus comprising: a discharging unit configured to discharge a sheet of paper. 2. The image forming apparatus according to claim 1, wherein the discharging unit is a retracting mechanism that retracts the sheet in the double feeding state to a route different from the discharging route. 3. The image forming apparatus according to claim 1, wherein the discharge means is a discharge tray changing mechanism that discharges the sheets in the double-feed state to a discharge tray different from a normal discharge tray.