JPH03267230A - Paper feeding device for picture-image forming device - Google Patents

Abstract

PURPOSE:To make paper-sheets feeding intervals constant by performing control in such a way that when paper sheets arrive earlier than a set timing, the drive of a paper-feeding means is once stopped to get the paper sheets to stand by and when the set time arrives, the drive is restarted; and that when paper sheets arrive later, feeding is continued without once stopping. CONSTITUTION:The time interval from the starting of a paper-feeding means 9 to the time when the end part of a paper sheet reaches a paper-sheet sensor S1 is measured, and the timing the paper sheet reaches the sensor S1 is compared with a set timing. As a result, when the paper sheet arrives earlier than the set timing, control is carried out to stop the drive of the paper-feeding means 9 for adjusting the timing to the set timing.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a paper feeding device for an image forming apparatus, and in particular, when paper is continuously fed from a paper storage device toward an image transfer section. The present invention relates to a method for setting the timing for feeding paper toward a paper transport path and controlling the interval between sheets to be constant.

(Prior Art) In image forming apparatuses that use electrophotography, such as electronic copying machines and laser printers, a toner image is formed on an image carrier such as a photoreceptor drum, and the toner image is transferred to paper. Later, such means are used to fuse the image through a fusing device to make a copy.

In the image forming apparatus described above, a large number of paper storage devices such as paper trays and paper feed cassettes are installed in the paper feed section of the device, and the paper of the required size is selected and fed to the image transfer section. methods are used.

In general image forming apparatuses, paper feeding means are separately provided corresponding to the paper storage devices, and each paper feeding means is connected to a nudger roller that rotates by pressing against the upper surface of the edge of the paper, and a nudger roller downstream thereof. It consists of a paper handling device located in the section.

Then, the paper taken out from the paper storage device by a nudger roller is sorted by a paper sorting device, separated one by one, and sent out toward an image transfer section such as a photoreceptor drum.

(Problems to be Solved by the Invention) In a device in which the paper feeding means is constituted by a nudger roller and a paper handling device, when the sheets carried out by the nudger roller overlap and are sent out, the paper below is is stopped by the paper sorting device and waits in front of the paper sorting device. Then, the next paper feeding signal is input and the paper feeding means is driven, so that the paper is sent out toward the image transfer section.

For example, in the case of a high-speed machine that makes a large number of copies per unit time, by activating the paper feed means at a timing that sets the paper transport interval to be very narrow, it is possible to reduce the amount of paper in the paper transport path. Sent close to. Therefore, the paper sent out from the paper storage device is
The drive timing for the paper feed means is set so that the next paper is immediately conveyed to that point and placed on standby as soon as it passes a predetermined detection section, so that the paper feeding function can be carried out efficiently.

In the case of the above-mentioned high-speed machine, if all the paper is taken out from the paper storage device each time the paper feeding means is operated, it is necessary to adjust the spacing between the paper in the paper transport path. It can be maintained constant.

On the other hand, for example, if the following paper is stopped at the paper sorting device and immediately fed out by the paper feed signal, then the length of the paper that protrudes from the paper storage device is , the paper is transported through the paper transport path with a narrower distance from the previous paper.

However, the space between the front and back sheets of paper becomes very narrow,
If two sheets of paper are conveyed one after another or very close together in the paper conveyance path, the paper sensor installed in the middle of the paper conveyance path may not be able to detect the paper and output a jam signal. Problems such as the trailing paper colliding with the preceding paper occur.

Since the image forming apparatus automatically stops each time such a signal is output, there are problems in that not only the copying efficiency is reduced but also an extra burden is placed on the operator.

(Object of the invention) The present invention is directed to the conventional IT system as described above.
This eliminates the drawback of
Detects the time it takes for the leading edge of the paper to reach a predetermined position, and according to that timing, sets the timing for feeding by the conveyance roller device installed in the paper conveyance path, maintaining a constant interval between paper feeds. SaI! The purpose is to provide a device that can

(Means and effects for solving the problems) The present invention has the following features:
A plurality of paper storage devices are installed in the paper feed section of the image forming apparatus,
A paper feeding means is arranged corresponding to each paper storage device, the paper feeding path from the paper feeding means is connected to the main transport path of the main body of the apparatus, and a transport roller device is arranged at the confluence of the two transport paths. The present invention also relates to a device in which a paper sensor is disposed immediately in front of the conveying roller device.

In the control device for an image forming apparatus according to the present invention, the time for the leading edge of the paper to reach the paper sensor is measured after the paper feeding means is activated, and the timing at which the paper reaches the paper sensor is determined based on the set timing. Ill tal stops the drive of the paper feeding means according to the set time if the paper arrives faster than the set timing compared to the time.
It is configured to do the following.

Further, in the paper feeding device of the image forming apparatus of the present invention, a timer for detecting a jam is temporarily stopped at the paper sensor portion while the paper is on standby without being nipped by the conveying roller device. Can be controlled.

Furthermore, in the paper feeding device of the image forming apparatus of the present invention, the signal of the set time for paper arrival at the paper sensor is used as a reference signal to determine the drive timing of the paper feeding means when feeding the next paper from the paper storage device. configuring, and
When sending out the next sheet, the timing of sending out the next sheet can be set in accordance with the paper size.

In addition to the above, in the present invention, after the paper is placed on standby at the paper sensor portion of the paper feed unit, when the paper is conveyed again, the feed roller (nudger roller) of the paper feed unit is simultaneously moved. The operation of the paper feeding means can be controlled so as to drive the paper feeding means.

As mentioned above, by controlling the timing of feeding out the paper, the image forming apparatus of the present invention can control the feeding interval of the paper at a constant value within the paper conveyance path, thereby improving the bee creation efficiency. I can do it.

Also, even if the paper spacing in the paper transport path is set narrow,
Since the interval can always be maintained constant, it is possible to prevent the paper sensor from erroneously detecting the paper and outputting a jam signal.

Furthermore, by using the paper feeding device of the image forming apparatus of the present invention, even when setting a mode in which one-sided copying and two-sided copying are performed alternately, it is possible to maintain a constant interval between feeding sheets. It becomes possible.

(Example) A paper feeding device of an image forming apparatus of the present invention will be described according to an illustrated example.

An image forming apparatus to which the present invention can be applied is shown as a printer 1 in FIG. 1, and the printer 1 includes one paper tray, an upper main body 2 provided with an image forming means, and a plurality of paper trays. and a lower cabinet 3 provided with an intermediate tray and an intermediate tray.

The printer 1 shown in FIG. 1 shows the configuration of an internal printer, and a writing device 11 using a laser beam is disposed on the photosensitive drum 10 of the printer 1, and the writing device 11 is arranged with a laser beam. Image information input to the device 11 is written onto the photosensitive drum 10.

Incidentally, a computer, an image reading means, or any other arbitrary device can be used as a device for outputting image information to the writing device.

Around the photoreceptor drum 10, there is a charging corotron 12 for uniformly charging the photoreceptor drum, a developing device 13 for attaching toner to the electrostatic latent image, and a groove formed on the photoreceptor drum. - A transfer/separation corotron 14 for transferring an image onto paper, and a cleaning device 1
5th prize will be placed.

Further, the paper is stored in a paper tray 5 and loaded into a paper feeder 6 of the printer, and the paper is fed out from the paper tray 5 by a paper feed roller 7 of the paper feeder and a paper handling device 8. It will be done.

As described above, the toner image is transferred onto the paper by the discharge from the rotron, and the paper is transferred to the paper transport device! 1
8 to the fixing device 16, where the fixing device heats and pressurizes the material and fixes the material to the discharge port 28.
so that it is discharged.

The paper conveyance path in the printer includes a pre-registration roller 21, a registration gate 22, and a registration roller 23 arranged at the end of the paper feed path 20 from the paper tray 5 and immediately before the image transfer section of the photosensitive drum 10. The leading end of the paper is positioned by the following steps, and the paper is fed out in synchronization with the toner image formed on the photoreceptor drum.

The paper to which the toner image has been transferred from the photoreceptor drum is
It is sent toward the fixing device 16 by the conveying device i18, passes through the fixing device f16, is completed as a copy, and is sent to the discharge path 2.
5 is transported. In the middle of the discharge path 25, there is a gate,
27, one discharge path 29 is provided, and the paper is delivered to the upper tray 3.
0, or can be discharged to a discharge tray via the discharge port 28.

Further, a non-discharge path 31 provided from the discharge path 25 via the gate 26 is provided with a curl removal device 32 .

Then, with the paper uncurled, it is ejected through the gate 33 to another ejection tray, sorter, etc., or the single-sided copied paper is sent out to the return path 35 connected to the lower part of the ejection tray. It will be done like this.

The cabinet 3 disposed at the bottom of the main body 2 of the printer is provided with a plurality of paper trays, an intermediate tray 40, and a return path 35 and a paper conveyance path 38 that penetrate vertically on both sides thereof. .

Further, a branching gate 36 for the intermediate tray 40 and a reversing path 37 are disposed in the return path 35, and by feeding the single-sided copied paper to the intermediate tray via the reversing path 37, the sheet is reversed. It is possible to store the paper in the intermediate tray in a state in which the paper has been copied on one side, and send out the paper with one-sided copying for back-side copying.

In the cabinet 3, paper trays 5a and 5b, large capacity trays 5C and t5, and an intermediate tray 40 are arranged above and below, and a structure similar to that of the paper tray 5 is provided in correspondence with each paper tray. Paper feeding units 5a, 5b and 6C are arranged.

The paper feeding unit is composed of means for transporting paper from each paper tray and means for connecting the paper transport paths of the upper and lower units. A conveyance path is configured. Note that even if a paper feeding unit from an intermediate tray is provided in the middle of the paper feeding unit, all parts of the paper conveyance path will be connected.

Further, unlike a normal intermediate tray, the intermediate tray 40 does not store a large number of sheets with single-sided copies on top of one another; instead, the intermediate tray 40 stores single-sided copied sheets introduced from the return path 35 during the copying operation of the main body. We are using a device that is configured so that it can be sent out sequentially depending on the situation.

The intermediate tray 40 is constructed of upper and lower guide plates, a plurality of sets of diagonal feed rollers 41, a gate 42 disposed at the end on the feed side, and a conveyance roller device. is used.

Then, the single-sided copied sheets accommodated through the gate 36 are aligned by the diagonal feed roller and stopped once, and a signal for back-side copying is output from the image forming apparatus main body. Then, the gate 42 is opened, and the single-sided copy sheet can be sent out toward the image transfer section.

(Configuration of Paper Feeding Section) FIG. 2 shows in detail each device provided between the paper feeding section and the image transfer section from the photoreceptor drum in the image forming apparatus. The example of the device shown in FIG. 2 includes a paper tray 5 in the main body, a paper tray 5a in the upper part of the cabinet, and a paper feed unit 6 provided corresponding to these paper trays.
．． 6a is shown.

Taking as an example the case where paper is sent out from the paper feeding unit 6a in the paper feeding means, the paper feeding unit 6a includes a nudger roller 7 for carrying out the paper from the paper tray, a paper sorting device w8, and a paper sorting device w8. are placed. The above-mentioned paper sorting device is shown as an example consisting of an upper paper feed roller and a lower sorting roller. By rotating in the opposite direction, the double-feeding sheets are separated and only one sheet is sent toward the paper feed path.

Further, a nudger roller 7 provided in the paper feeding unit
The drive of the paper sorting device 8 is configured such that when a paper feed signal is input, a clutch is connected, thereby connecting the drive system to a drive system (not shown) and driving the paper sorting device 8.

Furthermore, the nudger roller is supported by a frame that can swing relative to the drive shaft of the paper handling device, and is pressed against the paper by a drive means such as a solenoid for a short period of time required to carry out the paper from the paper tray. The swinging is controlled so that the The paper feeding unit is provided with a paper path 20a from a paper feeding means and a paper transport path 20 that vertically passes through the main body of the image forming apparatus.

The paper path 20a is configured to merge with the paper transport path at an upstream portion of the transport roller device 9 provided at the top of the unit, and the actuator is located at a position where it is not affected by the transport roller device at the merging portion. A paper sensor S1 is provided.

A registration gate 22 and front and rear registration rollers 21 and 23 are disposed immediately before the portion of the photosensitive drum 10 where the image is transferred by the transfer corotron 14.
A paper sensor S2 is placed immediately in front of the paper sensor S2.

In the paper transport device configured as described above, the paper fed from the paper tray 6a by the paper feed unit is
With the signal detected by paper sensor S1 obtained,
The paper passes through the paper transport path 20 and is sent toward the register device. Then, the paper is stopped by the registration gate 22 with the leading edge of the paper positioned, and then the gate 22 is opened in synchronization with the image formed on the photoreceptor drum 10, and the registration roller 23 directs the paper toward the image transfer section. The image is transferred.

(Paper feeding timing control> In the paper feeding device as shown in FIG. 2, if the paper is fed normally, the paper feeding is controlled as shown in the timing chart of FIG. 3. In the example shown in the timing chart of FIG. 3, when feeding the first and second sheets of paper, the clutch for driving the paper feed means and the solenoid for swinging the nudger roller are activated. drive,
It also shows the relationship between paper sensor detection.

In the paper conveyance control shown in the timing chart, when a paper feed signal is output, the feed clutch and the nudger roller solenoid are turned on at the same time.
The nudge roller is pressed against the paper, and the nudge roller and the roller of the paper sorting device are simultaneously driven.

The time for pressing the nudger roller against the paper may be the time until the leading edge of the paper is nipped between the rollers of the paper handling device, but normally the leading edge of the paper is nipped between the rollers of the paper handling device. After the paper is nipped, the solenoid is operated to press the nudge roller against the paper and cause the roller to perform the feeding action for a predetermined period of time.

Further, the drive time of the paper feeding unit is set so that the drive continues for a certain period of time after the leading edge of the paper is detected by the paper sensor S1. After being nipped by the conveyance roller device 9, the drive thereof is stopped after a predetermined time.

After sending out the first sheet of paper as described above,
The next sheet of paper is fed, but the timing of feeding the second sheet of paper is determined by the time T1 set in the image forming apparatus.
This is done at the set interval. Note that the time T
1 is a sensor S as shown in FIGS. 3 and 5.
The time shown is the sum of the time Ta from the start of detection by sensor S1 to the start of feeding of the second sheet, and the time Tb from the time the second sheet is sent out until it is detected by sensor S1. .

On the other hand, when the first sheet of paper is carried out by the nudger roller, it is sent out from the paper tray in a double feed state, and the second
When the first sheet of paper is fed out, there may be a case where the paper sensor detects it in a time Tn that is shorter than the target value TO.

If the sheets are fed at such a short timing, the interval between the sheets conveyed in the paper conveyance path becomes short, and there is a possibility that a paper sensor disposed in the paper conveyance path may make a false detection.

Therefore, in the image forming apparatus of the present invention, when the paper feed timing Tn detected by the paper sensor S1 disposed at the confluence of the paper paths is shorter than the target value TO, The control is programmed to turn off the feed clutch and interrupt the feed action.

Note that when the feeding action is interrupted, control is performed so that the leading edge of the paper is stopped at a position immediately before being nipped by the transport roller device 9, so that the leading edge of the paper is stopped at a position immediately before being nipped by the transport roller device 9, so that the leading edge of the paper is The effects continue.

In addition, when the clutch is turned on again to feed the paper after stopping the paper as described above, in order to assist the paper feeding ability of the paper sorting device, as shown in FIG. Najar for a very short time so that
The feeding action is performed by rollers.

By sequentially repeating the operations described above, the apparatus of the present invention achieves the initially set paper feeding timing (target value) as shown in the timing chart of FIG.
Accordingly, the paper can be transported within the paper transport path while maintaining the paper feeding interval constant.

In other words, when the second sheet of paper is fed early, as shown by ■, the sheet feeding means shown in FIG. The control will be such that the interruption will be carried out.

An example of the above-mentioned control is a case where the paper is detected by the paper sensor at an early timing, but in the paper feeding means of the present invention, due to reasons such as slippage occurring between the paper and the roller device, the paper cannot be fed out. There may be cases where the timing is delayed.

Therefore, if the paper detection timing is later than the set value, in order to avoid widening the transport interval for the previous paper, the paper feeding means continues to be driven and the paper is fed toward the paper transport path. The control program can be set up.

Then, by carrying out the paper feeding operation as described above, it is possible to perform an action of narrowing the widened gap while the previous paper is stopped at the registration position.

(a) When using the paper feeding timing setting means of the present invention configured as described above, even if rapid feeding of paper is detected and the operation of the paper feeding means is interrupted, the conventional jam detection means is activated. It is now possible to do so. In other words, in conventional jam detection devices, the jam detection timer is activated at the same time as the paper feed signal is output, and if the paper sensor installed in the paper transport path does not detect paper within a certain period of time, the jam detection timer is activated. , jam information is output.

On the other hand, when using the control means of the present invention, when it is detected that the timing of paper feeding is too early and the driving of the paper feeding means is interrupted, the paper sensor section detects that the paper is The program of the control device is set so that the jam detection timer is temporarily stopped while the paper is on standby without being nipped by the conveyance roller device 9.

Therefore, when the feeding action from the paper feeding means is interrupted, the counting of the timer is interrupted, and when the next drive signal is output and paper feeding is resumed, the counting of the timer is continued again. By doing so, the jam detection operation can be performed.

(b) Furthermore, when setting the driving timing of the paper feeding device of the present invention, as described above, the setting is made so that the paper feeding means is sequentially driven according to the target value TO to perform the paper feeding operation. However, apart from this, the paper sensor S
1 can also control the timing of sending out the next sheet based on the signal from which the sheet is detected.

By controlling the feeding of the paper as described above, it is also possible to increase the paper transport interval in the paper transport path to III'mI by driving the paper feeding means.

(C) Furthermore, in the image forming apparatus to which the present invention is applied,
Since a large number of paper trays, etc. are installed, and each paper tray stores paper of different sizes, when feeding paper from each paper tray, setting the feeding timing to a fixed interval TO allows for small For paper of this size, problems such as large gaps between the dark areas of the paper occur.

Therefore, in the present invention, the timing of paper feeding from the paper tray is set in accordance with the paper size, and the interval between the sheets transported in the paper transport path is maintained constant regardless of the paper size. Make things possible.

Therefore, in the case of small-sized paper, it is possible to set the timing for feeding from the paper feed tray short, to keep the interval between sheets constant, and to increase the number of copies per unit time.

In addition, in the embodiment of the present invention described above, the control of the paper feed interval in a printer was explained, but the control of the paper feed interval of the present invention is applicable to the control of the paper feed interval in an electronic copying machine or other image forming apparatus. It can also be applied to control of the paper feeding means when feeding paper from the storage device.

(Effects of the Invention) Since the present invention controls the timing of paper feeding as described above, in the image forming apparatus to which the present invention is applied, the paper feeding interval is kept constant within the paper conveyance path. control, and can improve copy creation efficiency.

Also, even if the paper spacing in the paper transport path is set narrow,
Since the interval can always be maintained constant, it is possible to prevent the paper sensor from erroneously detecting the paper and generating a jam signal.

Furthermore, by using the paper feeding device of the image forming apparatus of the present invention, even when setting a mode in which one-sided copying and two-sided copying are performed alternately, it is possible to maintain a constant interval between feeding sheets. It becomes possible.

6, 6a...Paper feeding unit, 7...Nudger roller, 8...Paper sorting device, 9...
... Conveyance roller device, 10 ... Photosensitive drum, 16 ... Fixing device, 18 ... Conveyance device, 22 ... Registration gate, 23.・・・・・・
Regirolla.

[Brief explanation of drawings]

Fig. 1 is a side view of a printer to which the present invention is applied;
The figure is an explanatory diagram showing the configuration of the paper feeding section, FIG. 3 is a timing chart for general control of the present invention, FIG. 4 is a timing chart showing control when the paper is detected early by the paper sensor, and FIG. FIG. 5 is a graph showing the conveyance state of paper.

Claims (5)

[Claims] (1) A plurality of paper accommodating devices are installed in the paper feeding section of the image forming apparatus, and a paper feeding means is arranged in correspondence with each paper accommodating device,
A paper feed path from the paper feed means is connected to a main transport path of the apparatus main body, a transport roller device is arranged at a confluence of the two transport paths, and a paper sensor is arranged immediately before the transport roller device. , the control device of the image forming apparatus is configured to measure the time it takes for the leading edge of the paper to reach the paper sensor after activating the paper feeding means, and compare the timing at which the paper reaches the paper sensor with the set time. If the paper arrives earlier than the set timing, the drive of the paper feeding means is temporarily stopped and the paper is placed on standby, and when the set time is reached, the drive is restarted and the paper is delayed. A paper feeding device for an image forming apparatus, characterized in that when the paper reaches the paper, it is controlled to feed the paper without stopping once. (2) A timer for detecting a jam is temporarily stopped while the paper is waiting in a state where the paper is not nipped by the conveying roller device at the paper sensor portion. Paper feeding device for image forming apparatus. (3) The signal of the set time when the paper arrives at the paper sensor is used as a reference signal to set the drive timing of the paper feeding means when feeding the next paper from the paper storage device. A paper feeding device for an image forming apparatus according to item 1 or 2. (4) A paper feeding device for an image forming apparatus according to claim 3, characterized in that when feeding the next sheet, the timing of feeding the next sheet is set in accordance with the paper size. . (5) After waiting the paper at the paper sensor part of the paper feeding means, when conveying the paper again, the operation of the paper feeding means is controlled so that the rollers of the paper feeding means are driven at the same time. A paper feeding device for an image forming apparatus according to any one of claims 1 to 4.