JP2003072987A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of improving operability by preventing jamming from leaving in a machine due to erroneous setting of sheets by a user to eliminate a jam releasing treatment. SOLUTION: When sheets are passed continuously by determining the sheet feed timing of a next sheet according to the information on the length of sheet size designated by a sheet size designating means, sheet feed jam is released when a second sheet jam is detected, the rear end of a preceding first sheet is detected by a resist sensor 30a, and then sheet feed operation is performed again.

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 such as a copying machine or a printer.

[0002]

2. Description of the Related Art In a conventional image forming apparatus, in order to align an image with respect to a fed sheet, the sheet is temporarily stopped by a registration roller or the like, and then restarted and then adjusted. .

At this time, the middle part to the rear end part of the paper which is applied to the paper feed roller of the paper feed part is fed along with the paper, and the paper feed part is not driven.

In this case, the sheet transportability is not always stable, and there is a tendency that it deteriorates especially in a system in which the cost of parts is reduced or a system in which the size is reduced.
There are also variations depending on the type of paper to be transported and the layout of the transport path.

As an image forming apparatus developed in order to prevent the paper carrying property from becoming unstable in this way, there is a conventional one as disclosed in, for example, Japanese Unexamined Patent Publication No. 09-226985. In the image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 226985, according to the paper feed unit and the paper type,
The sheet feeding roller is driven at the same time when the registration is restarted to stabilize the sheet carrying property.

[0006]

However, as described above, the paper feeding roller is driven simultaneously with the registration restart depending on the paper feeding unit and the paper type, so that the paper carrying property is stabilized. In the image forming apparatus, if the size of the paper to be conveyed is correct, there is usually no problem, but usually there is a paper size specification means such as a size setting dial for each tray, which allows the size of the paper set in the paper feed unit to be adjusted. Since it is fixed, the set size may differ from the size of the paper that is actually loaded.

In such a case, a problem arises in the timing of stopping the driven paper feed roller at the same time as the registration restart. When the paper that is actually set is large, the drive of the paper feed roller is cut off before reaching the rear end of the paper, so that the transportability deteriorates from the middle and the image is also affected. Further, in the case of a small paper, the paper feed roller continues to be driven even after the trailing edge of the paper has passed, so that the next paper may also be fed, causing a jam.

In order to avoid such a situation, for example, in the image forming apparatus disclosed in Japanese Unexamined Patent Publication No. 10-194529, the length of the sheet being conveyed is detected to determine the timing of driving the registration rollers and the size. When a difference is detected, the feeding operation of the succeeding paper is stopped before registration.

However, when the set paper is long, the paper feed operation is performed before the trailing edge of the preceding paper exits the paper feed unit, so that the paper is jammed without actually being fed. I will end up. If you stop the following paper,
Since the paper is stopped in the transport path, it is not possible to feed it from another paper feed section after that, so it is necessary to control to eject the paper and to detect the jam of the residual paper. There is a problem that becomes complicated.

In view of the above situation, the present invention can prevent a jam caused by a user's mistakenly setting a sheet from being left inside the machine, eliminate the jam clearing process, and improve the operability. The present invention is intended to provide an image forming apparatus that can be used.

[0011]

In order to solve the above-mentioned problems, in the invention according to claim 1, the paper feed section storing the paper and the size of the paper stored in the paper feed section are designated. A paper size designating unit, a paper feed roller for feeding the papers one by one from a paper feed unit, and a registration for aligning an image writing position by temporarily stopping the conveyed paper and then restarting the operation. In an image forming apparatus including a roller and a sensor for detecting whether a sheet has reached or passed a registration position, the timing of feeding the next sheet according to the length information of the sheet size designated by the sheet size designating means. When you set
When the paper feed jam of the second sheet is detected, the paper feed jam is released, and after the trailing edge of the preceding first paper is detected by the sensor at the registration position, the paper feed operation is executed again. The image forming apparatus configured as described above is the most main feature.

According to a second aspect of the invention, in the image forming apparatus according to the first aspect, the paper feed roller is operated at the same time as the restart by the registration roller, and the rear end of the paper reaches the paper feed port of the paper feed section. The main feature of the image forming apparatus is that the paper feed roller is stopped at a timing, and when the paper feed operation is performed again, the paper feed roller is not operated when the registration roller restarts.

According to the third aspect of the present invention, in the image forming apparatus according to the second aspect, if the result of performing the sheet feeding operation again is normal, the trailing edge detection is performed when the first sheet is conveyed. The main feature of the image forming apparatus is that it is configured to determine the sheet feeding timing for the third and subsequent sheets based on the information on the sheet length detected at the same time.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic structural diagram of an example of an embodiment of an image forming apparatus of the present invention. As shown in FIG. 1, an image forming section 2 is provided at the center of a housing 1 of the image forming apparatus. The image forming unit 2 is formed by disposing a charging roller 4, a writing unit 5, a developing unit 6, a transfer roller 7, and a cleaning unit 8 around the photoconductor 3. In the image forming section 2, the photoconductor 3 is uniformly charged by the charging roller 4, and the charged portion is scanned with a laser beam modulated according to image data by the writing unit 5 to form an electrostatic latent image. Then, the electrostatic latent image is developed by the developing unit 6, the developed image on the photoconductor 3 is transferred to a sheet by the transfer roller 7, and the residual toner on the photoconductor 3 is cleaned by the cleaning unit 8. There is.

In the paper conveyance path 9 passing between the photoconductor 3 and the transfer roller 7, heat and pressure are applied in the process of conveying the paper passing through the transfer roller 7 to fix the toner on the paper. A unit 10 is provided. Further, the downstream side of the fixing unit 10 of the paper transport path 9 is branched into a paper discharge path 12 leading to a paper discharge tray 11 formed on the housing 1 and a reversing path 13 and discharged to the branch point. A switching claw 14 for switching the paper path is rotatably provided. further,
Below the photoconductor 3, a double-sided unit 15 is provided for re-feeding the sheet that has been inverted and returned from the inversion path 13 toward the image forming unit 2.

Further, a manual feed tray 16 and a paper feed roller 17 for feeding the paper inserted in the manual feed tray 16 to the image forming section 2 are provided on one side of the housing 1. A paper feed tray 19, which is a paper feed unit for storing a large number of papers in a stacked state, is detachably mounted below the housing 1. Above the paper feed tray 19, the paper feed tray 1 is provided.
The paper inside 9 is fed through the paper feeding passage 20 to the above-mentioned paper conveying passage 9
A paper feed roller 21 for feeding paper is rotatably provided. Further, a pair of registration rollers 22 arranged between the paper feed rollers 17 and 21 and the photoconductor 3 are provided in the paper transport path 9. A registration sensor 30a is arranged near the registration roller 22 on the paper feed side.

Next, referring to FIG. 2, an outline of the electrical connection configuration of the image forming apparatus will be described. A main control section 23 of a microcomputer configuration is provided, and the writing unit 5 and the fixing unit 10 described above are provided therein. , Double-sided unit 15, high-voltage drive unit 24, driver 26 that drives the motor 25, driver 2 that drives the paper feed clutch 27
8, a controller 29, and various sensors 30 are connected.

Here, the high-voltage driving section 24 is a means for driving a portion requiring a high-voltage power source, such as the charging roller 4, the developing unit 6, and the transfer roller 7 arranged around the photosensitive member 3. A motor (main motor) 25 is a drive source of a rotary system such as the photoconductor 3 and the fixing unit 10, and its rotational force is also transmitted to the paper feed rollers 17 and 21 via the paper feed clutch 27.

The controller 29 has a function of an interface connected to a host computer (not shown), and further has a function of giving an instruction of image data editing, image data transfer, and image formation to the main controller 23. Hold.
Although not shown, the various sensors 30 are a temperature sensor that outputs a signal corresponding to the temperature of the fixing unit 10 and the like, a paper ejection sensor that is arranged in the paper ejection passage 12 and that outputs a signal depending on the conveyance state of the paper, a paper feed tray It includes a tray sensor that outputs a signal according to the insertion / removal state of 19, a paper end sensor that outputs a signal depending on the presence or absence of paper in the manual feed tray 16 or the paper feed tray 19, the registration sensor 30a shown in FIG.

The main control section 23 controls the mechanical load in the image forming apparatus, writes an image by the writing unit 5, monitors the sheet conveyance state based on the outputs of various sensors 30, and the states of other sections, and sets a preset program. Is used to control the operation of each part.

FIG. 3 is a flow chart for explaining the first example of the operation relating to the image forming apparatus of the present invention. In FIG. 3, after printing is started in STEP1, the paper feeding clutch (paper feeding CL) 27 is turned on in STEP2 to start the paper feeding operation. Thereafter, in STEP 3, it is checked whether the resist sensor 30a is on. At this time, STEP 10 checks for a fixed time-out. After the registration sensor 30a is turned on in STEP3, a delay for bending is set in STEP4, and then the sheet feeding clutch 27 is turned off in STEP5. At this time, in STEP 6, the writing of an image on the photoconductor 3 is prepared under the control of the controller 29. When the preparation is completed, the writing unit 5 writes the electrostatic latent image on the photoconductor 3, and the developing unit 6 To start development. This state is recognized as the start of image formation by monitoring the CPU of the main controller 23. S in synchronization with this
At TEP 7, the registration clutch (registration CL) is turned on, and the paper is sent toward the photoconductor 3. After that, although not shown, the sheet is conveyed to the fixing unit 10 as a fixing unit, and is discharged to the outside of the machine after fixing the image. Then, ST
In EP8, the next paper feed is checked. If there is no next paper feed, printing ends. If there is next paper feed, the timing of the next paper feed is measured in STEP9, and STEP2 and subsequent steps are repeated. The next paper feed timing is calculated based on the paper size and the paper feed interval, and is generally set to be shorter than the print interval due to registration start.

On the other hand, if the time-out occurs in STEP 10, it is checked in STEP 11 whether or not the paper has not reached the registration sensor 30a for the first time. Here, the first page is excluded. If the result is YES,
In STEP 12, the paper feed clutch 27 is temporarily stopped and the STE
In P13, it waits for the preceding paper to pass the registration position. Here, the meaning of waiting for the preceding paper to pass is to consider the case where the size of the paper actually set by the user is wrong. Since the paper feed timing is determined based on the size information that has been set, if the size that is actually set is large, the next paper feed will occur even if the trailing edge of the preceding paper is at the paper feed position. It will work. 2 for control
It means that the paper feeding operation is being performed for the first sheet, and the actual paper is not feeding. Therefore, in STEP 13, it is checked that the trailing edge of the preceding paper has surely passed the registration position, and then a retry operation is performed to return to STEP 2. If the retry result in STEP 11 also times out, in STEP 14 it is determined that a paper feed jam has not occurred.

As described above, in the example shown in FIG.
When the paper feed jam of the first sheet is detected, the paper feed jam is temporarily canceled, and the paper feed operation is executed again after the trailing edge of the preceding first paper is detected by the registration sensor 30a. Therefore, it is possible to prevent the jam caused by the user's mistakenly setting the paper from being left inside the machine, to eliminate the jam release process, and to improve the operability.

FIG. 4 is a flow chart for explaining the second example of the operation relating to the image forming apparatus of the present invention. In FIG. 4, after printing starts in STEP1, the paper feeding clutch (paper feeding CL) 27 is turned on in STEP2 to start the paper feeding operation. Thereafter, in STEP 3, it is checked whether the resist sensor 30a is on. At this time, STEP 15 checks for a fixed time-out. After the registration sensor 30a is turned on in STEP3, a delay for bending is set in STEP4, and then the sheet feeding clutch 27 is turned off in STEP5. At this time, in STEP 6, the writing of an image on the photoconductor 3 is prepared under the control of the controller 29. When the preparation is completed, the writing unit 5 writes the electrostatic latent image on the photoconductor 3, and the developing unit 6 To start development. This state is recognized as the start of image formation by monitoring the CPU of the main controller 23. S in synchronization with this
The registration clutch (registration CL) is turned on at TEP 7, and the paper feed clutch 27 is normally turned on at STEP 9 to feed the paper toward the photoconductor 3. STEP
Item 8 will be described later. When the trailing edge of the sheet has passed through the sheet feeding section in STEP 11, the sheet feeding clutch 27 is set in STEP 12.
To turn off. After that, although not shown, the sheet is conveyed to the fixing unit 10 as a fixing unit, and is discharged to the outside of the machine after fixing the image. Next, in STEP 13, the next paper feed is checked. If there is no next paper feed, the printing ends, but if there is next paper feed, the timing of the next paper feed is measured in STEP 14, and STEP 2 and subsequent steps are repeated. The next paper feed timing is calculated based on the paper size and the paper feed interval, and is generally set to be shorter than the print interval due to registration start.

On the other hand, if the time-out occurs at STEP 15, it is checked at STEP 16 whether the paper has not reached the registration sensor 30a for the first time. Here, the first page is excluded. If the result is YES,
At STEP 17, the paper feed clutch 27 is temporarily stopped and the STE
The retry flag is set at P18. This flag is S
By checking with TEP8, the paper feed clutch 27 is provided when the registration is restarted during the retry operation.
It does not turn on. The retry operation is to give top priority to discharging the paper existing in the machine out of the machine. The retry flag is reset in STEP 10. In STEP 19, the process waits for the preceding paper to pass the registration position. Here, the meaning of waiting for the preceding paper to pass is to consider the case where the size of the paper actually set by the user is wrong. Since the paper feed timing is determined based on the size information that has been set, if the size that is actually set is large, the next paper feed will occur even if the trailing edge of the preceding paper is at the paper feed position. It will work. It is assumed that the paper feeding operation for the second sheet is being performed in a control manner, and the actual paper feeding operation is not performed. Also, if the size actually set is small, S
Since the sheet feeding clutch 27 is turned on at TEP9, a plurality of sheets are continuously fed, and the same operation is performed. Therefore, in STEP 19, it is checked that the trailing edge of the preceding paper has surely passed the registration position, and then a retry operation is performed to return to STEP 2. In addition, if the result of retrying in STEP 15 also times out,
In STEP 20, the non-feeding jam is determined.

As described above, in the example shown in FIG.
When the paper feed jam of the first sheet is detected, the paper feed jam is temporarily canceled, and the paper feed operation is executed again after the trailing edge of the preceding first paper is detected by the registration sensor 30a. In this case, the paper feed roller is not operated only in that case, so that invalid paper can be reliably ejected out of the machine, and the jam caused by the user's mistake in setting the paper is not left inside the machine. Therefore, it is possible to eliminate the jam clearing process and improve the operability.

FIG. 5 is a flow chart for explaining the third example of the operation relating to the image forming apparatus of the present invention. In FIG. 5, after printing starts in STEP1, the paper feeding clutch (paper feeding CL) 27 is turned on in STEP2 to start the paper feeding operation. Thereafter, in STEP 3, it is checked whether the resist sensor 30a is on. At this time, STEP 14 checks for a fixed time-out. After the registration sensor 30a is turned on in STEP3, a delay for bending is set in STEP4, and then the sheet feeding clutch 27 is turned off in STEP5. At this time, in STEP 6, the writing of an image on the photoconductor 3 is prepared under the control of the controller 29. When the preparation is completed, the writing unit 5 writes the electrostatic latent image on the photoconductor 3, and the developing unit 6 To start development. This state is recognized as the start of image formation by monitoring the CPU of the main controller 23. S in synchronization with this
The registration clutch (registration CL) is turned on at TEP 7, and the paper feed clutch 27 is normally turned on at STEP 9 to feed the paper toward the photoconductor 3. STEP
Item 8 will be described later. When the trailing edge of the sheet has passed through the sheet feeding section in STEP 10, the sheet feeding clutch 27 is set in STEP 11.
To turn off. After that, although not shown, the sheet is conveyed to the fixing unit 10 as a fixing unit, and is discharged to the outside of the machine after fixing the image. Next, in STEP 12, the next paper feed is checked. If there is no next paper feed, printing ends. If there is next paper feed, the timing of the next paper feed is measured in STEP 13, and STEP 2 and subsequent steps are repeated. The next paper feed timing is calculated based on the paper size and the paper feed interval, and is generally set to be shorter than the print interval due to registration start.

On the other hand, if the time-out occurs in STEP 14, the retry flag, which will be described later, is checked, and if it is set, the non-feeding jam is determined in STEP 20. Also, in STEP 16, it is checked whether the paper has not reached the registration sensor 30a for the first time. Here, the first page is excluded. If the result is YES, in step 17, the paper feed clutch 27 is temporarily stopped, and S
The retry flag is set at TEP18. This flag is referred to in the above-mentioned STEP8 and STEP15. S
If the flag is set in TEP8, the process of turning on the paper feed clutch 27 is not performed when the registration is restarted during the retry operation. The retry operation is to give top priority to discharging the paper existing in the machine out of the machine. In addition, the registration sensor 30
The actual paper length is detected from the time when it passes a, and the STE
Recalculate the next paper feed timing in P13,
Even if a size error occurs, it is operated so as not to jam.

Further, in STEP15, the jam occurs when the retry operation has already been performed, so that the non-feeding jam is determined.

In STEP 19, the process waits for the preceding paper to pass the registration position. Here, the meaning of waiting for the preceding paper to pass is to consider the case where the size of the paper actually set by the user is wrong. Since the paper feed timing is determined based on the size information that has been set, if the size that is actually set is large, the next paper feed will occur even if the trailing edge of the preceding paper is at the paper feed position. It will work. It is assumed that the paper feeding operation for the second sheet is being performed in a control manner, and the actual paper feeding operation is not performed. Further, even when the size actually set is small, a plurality of sheets are continuously fed to turn on the sheet feeding clutch 27 in STEP 9, and the same operation is performed. Therefore, STE
In P19, check that the trailing edge of the preceding paper has surely passed the registration position, and then perform a retry operation STEP2.
To return to. In addition, if the result of the retry in STEP 15 also times out, STEP 20
Confirm that no paper is jammed.

As described above, in the example shown in FIG.
When the paper feed jam of the first sheet is detected, the paper feed jam is temporarily canceled, and the paper feed operation is executed again after the trailing edge of the preceding first paper is detected by the registration sensor 30a. In addition, for the third and subsequent sheets, the sheet feed timing is determined according to the sheet length information at the time of detecting the trailing edge of the first sheet, so that the invalid sheet can be reliably discharged to the outside of the machine. Therefore, it is possible to prevent the jam caused by the user's mistakenly setting the paper from being left in the machine, eliminate the jam release process, and improve the operability.

[0032]

As described above, the first aspect of the present invention is as described above.
According to the image forming apparatus described above, when the paper feed jam of the second sheet is detected, the paper feed jam is temporarily canceled and the preceding 1
The paper feed operation is executed again after the trailing edge of the first sheet of paper is detected by the sensor at the registration position. As a result, the jam clearing process can be eliminated, and the excellent operability can be improved.

According to the image forming apparatus of the second aspect of the present invention, when the paper feed jam of the second sheet is detected, the paper feed jam is temporarily released and the trailing edge of the preceding first paper sheet is released. After the sheet is detected by the sensor at the registration position, the sheet feeding operation is executed again, and the sheet feeding roller is not operated only in that case, so that the invalid sheet can be reliably discharged to the outside of the machine. Therefore, it is possible to prevent the jam caused by the user's mistakenly setting the paper from being left in the machine, eliminate the jam release process, and improve the operability.

According to the image forming apparatus of the third aspect of the present invention, when the paper feed jam of the second sheet is detected, the paper feed jam is temporarily released and the trailing edge of the preceding first paper sheet is released. Is detected by the sensor at the registration position, the sheet feeding operation is executed again, and the sheet feeding timing is set for the third and subsequent sheets in accordance with the sheet length information when the trailing edge of the first sheet is detected. Since it was decided, it is possible to reliably discharge invalid paper outside the machine, and it is possible to prevent the jam caused by the user's mistakenly setting the paper from remaining inside the machine and eliminate the jam clearing process. It is possible to obtain the excellent effect that the operability can be improved.

[Brief description of drawings]

FIG. 1 is a schematic structural diagram of an example of an embodiment of an image forming apparatus of the present invention.

FIG. 2 is an electrical connection configuration diagram in an example of a mode for carrying out the image forming apparatus of the present invention.

FIG. 3 is a flowchart illustrating a first example of an operation relating to the image forming apparatus of the present invention.

FIG. 4 is a flowchart illustrating a second example of the operation relating to the image forming apparatus of the present invention.

FIG. 5 is a flowchart illustrating a third example of the operation relating to the image forming apparatus of the present invention.

[Explanation of symbols]

1 case 2 Image forming section 3 photoconductor 4 charging roller 5 writing unit 6 Development unit 7 Transfer roller 8 cleaning unit 9 Paper transport path 10 fixing unit 12 Paper output passage 16 Bypass tray (paper feeder) 17 Paper feed roller 19 Paper tray (paper feeder) 20 paper feed path 21 Paper feed roller 22 Registration roller 30a Registration sensor (sensor)

Continued front page    F-term (reference) 2H027 DC14 DC19 DE07 DE10 ED17                       EE07 EK07                 2H072 AA02 AA13 AA23 AA24 AB03                       AB07 BA03 BA12 CA01 CB07                       JA02                 3F048 AA02 AA05 AB01 BA14 BB02                       CB04 CC04 DA06 DB12 DC14                       EA05 EB30

Claims (3)

[Claims] 1. A paper feed unit for storing paper, a paper size designating unit for designating the size of the paper stored in the paper feed unit, and a paper feed for feeding the paper one by one from the paper feed unit. Equipped with a roller, a registration roller for stopping the conveyed paper once and then restarting the operation to align the image writing position, and a sensor for detecting that the paper has reached or passed the registration position. In the image forming apparatus, when the second paper feed jam is detected when the paper feed timing of the next paper is determined in accordance with the length information of the paper size designated by the paper size designation means and the paper is continuously fed. Is configured to execute the paper feed operation again after the paper feed jam is released and the trailing edge of the preceding first sheet is detected by the sensor at the registration position. Forming equipment. 2. The paper feed roller is operated at the same time as the restart by the registration roller, and the paper feed roller is stopped at the timing when the trailing edge of the paper reaches the paper feed port of the paper feed unit, and the paper is fed again. 2. The image forming apparatus according to claim 1, wherein when the operation is performed, the paper feed roller is not operated when the registration roller is restarted. 3. When the result of performing the paper feeding operation again is normal, the third and subsequent sheets are detected based on the information on the sheet length detected at the same time as the trailing edge detection when the first sheet is conveyed. The image forming apparatus according to claim 2, wherein the image forming apparatus is configured to determine a paper feed timing.