JPH02282138A - Sheet material feeder - Google Patents

Abstract

PURPOSE:To detect deterioration of the feeding ability of a feed means by providing a sensor for measuring a feed time by detecting a sheet material fed from a feed means. CONSTITUTION:A sensor 18 for measuring a feed time by detecting a sheet material B fed from a feed means 8 is provided. Measuring the feed time of the sheet material B by this sensor 18, the feed means 8 is detected in its deterioration of feed ability. Also, by providing a control means for controlling a driving speed of the feed means 8 in response to a number of times by which the measured time by the sensor 18 exceeds the threshold value, feed action of the sheet material B can be prevented by resetting the driving speed of the feed means 8 in accordance with the deterioration of the feeding ability.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a sheet material feeding device applied to image forming apparatuses such as copying machines and printers.

<Prior Art> Conventionally, various sheet material feeding devices applied to image forming apparatuses such as copying machines and printers have been developed and put into practical use.

Among them, an example of a sheet material feeding device widely applied to copying machines is shown below.

After the user sets a desired value on the operation section, the user presses a copy start button, and the document fed into the automatic document feeder is fed onto the glass surface of the document table.

On the other hand, transfer paper of the size set in the operation section is fed from a cassette or paper deck to a pair of registration rollers by paper feed rollers, respectively.

Then, the leading edge of the original image formed on the photosensitive drum, which is an image carrier, and the transfer paper are synchronously conveyed to the transfer section by the pair of registration rollers, and image transfer is performed.

In the above-mentioned sheet material feeding device, paper feeding failures may occur when the surface of the paper feeding roller becomes worn out or its friction coefficient begins to decrease due to paper dust or the like.

For this reason, a paper presence/absence detection sensor is usually provided just before a pair of registration rollers to measure the feeding time of the transfer paper, and the apparatus itself is configured to determine whether the transfer paper is being fed as scheduled.

In many cases, if the sensor cannot detect the transfer paper within a predetermined time after feeding the transfer paper from the cassette or the like, it is assumed that there is a paper feeding failure and the drive of the apparatus is stopped.

In addition, the sensor is placed near the paper feed roller, and even if the transfer paper is not fed, the feeding operation is repeated several times, and if the sensor still cannot detect the transfer paper, it is determined that the paper feed is defective. In many cases, the system is configured to stop driving the device.

<Problems to be Solved by the Invention> However, in the above-mentioned conventional technology, when a paper presence/absence detection sensor is provided just before a pair of registration rollers, the If the sensor cannot detect transfer paper, it is configured to automatically stop the drive of the device, so even if the feeding of the transfer paper is delayed due to wear of the paper feed roller, rather than a jam, the device will stop. Each time the machine stops, the user must take the same steps as in the case of a paper jam, then insert the original again and make copies again, which may interrupt the work and reduce work efficiency.

In addition, even if you try to feed the transfer paper again after handling the paper jam, etc., the paper feeding capacity of the paper feed roller will still be reduced, so the paper feeding failure will progress. There was a risk that work efficiency would decrease in many cases where service personnel were called.

Furthermore, if the sensor is placed near the paper feed roller, if the sensor cannot detect the transfer paper, it may be possible to feed the transfer paper by repeating the paper feeding operation again; Since the paper feeding ability of the rollers continues to decrease, the paper feeding failure progresses and the paper feeding operation becomes unstable, which only slightly increases the time it takes to call a service person.

The present invention solves the above-mentioned problems of the prior art, and maintains the sheet material feeding operation by reducing the driving speed of the feeding device in response to a decrease in the sheet material feeding ability of the feeding device. The present invention provides a sheet material feeding device that prevents further progress of feeding defects.

Means for Solving the Problems〉 Means for solving the problems of the prior art described above and applied to the embodiments described below include a feeding means for feeding the sheet material, and a feeding means for feeding the sheet material from the feeding means. The apparatus includes a sensor for detecting the sheet material and measuring the feeding time, and a control means for controlling the driving speed of the feeding means according to the number of times the time measured by the sensor exceeds a threshold value. .

<Operation> According to the above means, since the sensor is provided to detect the sheet material fed by the feeding means and measure the feeding time, the feeding time of the sheet material can be measured by the sensor. It is possible to detect a decrease in the feeding capacity of the feeding means.

Further, since a control means is provided for controlling the driving speed of the feeding means according to the number of times the time measured by the sensor exceeds a threshold value, the driving speed of the feeding means is set again according to a decrease in feeding capacity. By doing so, the sheet material feeding operation can be maintained.

Therefore, it is possible to prevent further progress of feeding defects due to a decrease in the feeding capacity of the sheet material feeding means.

<Example> Hereinafter, an example of a sheet material feeding device to which the present invention is applied will be described with reference to the drawings.

FIG. 1 is a cross-sectional explanatory diagram of a sheet material feeding device, FIG. 2 is an explanatory diagram showing a schematic configuration of a copying machine to which the sheet material feeding device is applied, and FIG. 3 is a control system of the sheet material feeding device. The block diagram of FIG. 4 is a flowchart showing its operation.

First, a schematic configuration of a copying machine to which a sheet material feeding device is applied will be described with reference to FIG.

Reference numeral 1 denotes an automatic document feeder that conveys and places the document A on a platen glass.

Reference numeral 2 denotes an optical system having a lamp for irradiating light onto the document A, a reflecting mirror, a small-diameter imaging element array, etc., and irradiating reflected light onto an image carrier to be described later for exposure.

3 is a primary charger built into the copier.

This is an image forming unit that includes an image carrier, a developing device, a transfer/separation charger, a cleaning device, and the like.

On one side of the copying machine main body, there is a cassette 4, which is a loading means for feeding and loading a plurality of sheets of transfer paper B such as plain paper or plastic sheets, or a cassette 4 which loads the transfer paper B and which transfers the transfer paper B. Each paper deck 5 is provided with a loading platform that moves up and down as the paper is fed.

Reference numeral 6 denotes a sheet material feeding means having a pickup roller 7, a feeding roller 8, etc. for feeding the transfer paper B one by one from the cassette 4 or the like. The transfer paper B fed by the feeding means 6 is conveyed to the temporarily stopped registration rollers 9 to correct the skew, and then the registration rollers 9 are driven to form the image on the image carrier. The image is transferred to the transfer section in synchronization with the leading edge of the image.

Reference numeral 10 denotes a one-step feeding device that transports the transfer paper B after transfer recording from the image carrier, 11 a fixing device for permanently fixing the image transferred to the transfer paper B, and 12 a transfer unit after the image is fixed. The paper ejection roller 13 for ejecting the paper B is a paper ejection tray on which the ejected transfer paper B is stacked.

After the image has been transferred, the transfer paper B is transported by the transport device 10 to the fixing device 11, where the image is fixed thereon, and then transported by the paper discharge roller 12 and discharged to the paper discharge tray 3.

Next, a sheet material feeding device applied to the above-mentioned copying machine will be explained with reference to FIG.

In FIG. 1, there is a pink-up opening and
- The roller 7 is in contact. Above pink amplifier roller 7
A feeding roller 8 is provided on the downstream side (hereinafter simply referred to as downstream side) of the transfer paper B in the conveyance direction. A belt 14 is provided between the pink amplifier roller 7 and the feeding roller 8.
are suspended, and are configured to rotate in synchronization by transmitting the driving force supplied by a motor 15 connected to the rotating shaft of the feed roller 8 via the belt 14. Further, the feed roller 8 is provided with a driven roller 8' that can rotate as driven by the feed roller 8.

On the downstream side of the feeding roller 8 and the driven roller 8', there are guide plates 16 provided above and below to guide the fed transfer paper B, and a diagram for conveying the transfer paper B to the registration rollers 9. Conveying rollers 17 driven by driving means (not shown) are arranged in sequence.

Further, on the downstream side of the conveyance roller 17, a paper detection sensor 1 is provided for detecting the leading edge of the transfer paper B being conveyed and measuring the feeding time of the transfer paper B fed by the feeding means 6.
8 are arranged.

The pink-up roller 7 and the feeding roller rotate 80 times by controlling the driving speed of the motor 15 that drives the feeding means 6 according to the number of times the sensor's measurement time per day exceeds a preset threshold. The speed can be controlled.

Further, on the downstream side of the conveyance roller 17, there is provided a guide plate 19 provided above and below, and the transfer paper B forms a loop along the guide plate 19 and is temporarily stopped by a registration roller. After correcting the skew by bringing the leading end into contact with the nip of the image carrier 9, the registration rollers 9 are driven to convey the image to the transfer section in synchronization with the leading end of the image on the image carrier.

Here, the control system of the sheet material feeding device will be explained with reference to the block diagram shown in FIG. 3.

CPU20a such as a microprocessor, the cPU20
ROM that stores control programs and various data for a.
20b, and a RAM 20 which is used as a work area for the CPU 20a and also temporarily stores various data.
A control unit 20 equipped with C, an interface 21, an operation unit 22, a paper detection sensor 18, a motor driver 23 that drives each motor, a feed motor 24 that drives the feed roller 8, and a registration roller 9. It includes a registration drive motor 25, a display section 26, and the like.

The control unit 20 receives the feeding number 13 of the transfer paper B from the operation unit 22 or the detection signal from the paper detection sensor 23 through the interface 21 . Further, from the control unit 20, via the interface 21, an ON/OFF signal for the feed motor 24 and the registration drive motor 25, or a control signal for the rotation speed of the feed motor 24,
Change in rotational speed of the feed roller 8 or change in the rotation speed of the feed roller 8
When the rotational speed change reaches a predetermined number of times, a serviceman call is displayed on the display section 26.

Next, the control operation of the control system of the sheet material feeding device is controlled in a fourth manner.
This will be explained with reference to the flowchart shown in the figure.

First, the setting of each value in the control section 20 in steps S1 to S3 will be explained.

In step s1, the serviceman call line indicating that maintenance is required is connected to P[iJ, feed motor 2
The speed-down determination line for reducing the rotational speed of No. 4 is set to 0 times, the arrival time threshold of transfer paper B is set to 8 seconds, and the monitoring range is set to r times.

In addition, in steps S2 and S3, the number of times n of speeding down the feed motor 24 and the number of times m of paper feeding of the transfer paper B are each set to zero.

Next, in step S4, the transfer sheet B is transferred from the operating section 22.
When the feeding signal is input, the feeding motor 24 is driven, the pink-up roller 7 and the feeding roller 8 are driven to rotate, and feeding of the transfer paper B is started.

Then, in step S5, the number of fed sheets is counted per sheet, and in step S6, the arrival time t from the feeding of transfer paper B to the sensor 18 is measured.

In this case, the distance from the drive of the feed roller 8 until the leading edge of the transfer paper B reaches the paper detection sensor 18 is 1 (+n).
, when the rotational speed of the feed roller 8 and the pickup roller 7 is v (am/s), the arrival time is t=l/v
(s). As the feeding operation of the transfer paper B progresses, as described above, slipping occurs when the transfer paper B is kicked out due to a decrease in the frictional force due to wear of the pickup roller 7 and the feeding roller 8 or due to paper dust adhering to the roller surface. As a result, the above mentioned arrival time also increases.

Therefore, in step 87 to step SIO, it is determined whether the arrival time t has increased and exceeded the threshold value S, and the number of times the arrival time t has exceeded the threshold value S within the monitor range r is counted. .

At this time, the number of times the arrival time t has exceeded the threshold S during the past r times since the m-th paper feed is the number q when L exceeds S for any number of paper feeds k (however, m-r11≦5m). When it exceeds F(k)=1
．． Using a determination flag F (k) that becomes F (k) - 0 when t does not exceed S, it can be expressed as q=ΣF (k).

Therefore, in step S7, the arrival time t is determined to be the threshold value S.
Determine whether or not the limit has been exceeded, and if so, proceed to step S.
8, it is determined that F(*)=1, and if it is not exceeded, the process advances to step S9, and it is determined that F(@1)=O, and the process returns to step S4 again to feed the transfer paper B. Continue working.

If it is determined in step S8 that F(m)=1, the process proceeds to step SIO where it is determined whether or not q has exceeded the speed-down determination line Q.

If the value of q exceeds Q, it is determined that there is a high possibility that a paper feeding failure will occur, and the process proceeds to step S11, where the number n of speed reductions of the feeding motor 24 is counted. If the value of q does not exceed Q, the process returns to step S4 to continue feeding the transfer paper B, as described above.

Next, in step S12, it is determined whether or not the number of speed-downs n of the feeding motor 24 exceeds a serviceman call line P, which is a preset threshold. Display serviceman call.

Therefore, maintenance can be performed accurately in the event of paper feeding failure due to some unexpected accident or in the case where the speed of the pickup roller 7 and the feeding roller 8 is significantly reduced.

If the speed-down number n does not exceed the serviceman call line P, in step S14, q
The appropriate drive speed of the feed motor 24 is determined according to the value of , and the rotational speeds of the pickup roller 7 and the feed roller 8 are changed. That is, it is possible to suppress the drive speed of the feed motor 24 and reduce the rotational speed of the feed roller 8 and pickup roller 7 depending on the degree of paper feeding failure, and it is possible to maintain stable feeding operation. I can do it.

In this case, the slip during feeding of transfer paper B is determined by the paper feeding speed,
Pick up roller 7, feed roller 8 and transfer paper B
Because it depends on the coefficient of friction between the paper and paper feed pressure, etc.
It has been found that when the coefficient of friction between the knob roller 7 and the feeding roller 8 and the transfer paper B decreases, it is effective to lower the paper feeding speed and feed the paper. In addition, although the copying speed of a copying machine should normally be constant, this increases the frequency of jams, and it is better to stop the drive of the device to ensure image formation even if the copying speed decreases. It is wiser to do so.

Then, in step 315 and the step knob 316, the threshold value S of the arrival time of the transfer paper B and the value of the speed-down judgment line Q are set again according to the rotational speed of the pick-up roller 7 and the feed roller 8. After that, the display section 26 displays the fact that the speed has been reduced or the speed after the speed has been reduced. In this way, the surface conditions of the pink-up roller 7 and the feeding roller 8 can be visually checked.

Particularly, in the case of an apparatus having a plurality of sheet material feeding means 6, convenience during maintenance can be achieved by displaying only the speed reduction indication of the roller whose feeding capacity has decreased.

After resetting the values of the threshold value S and the speed-down determination line Q, the process returns to step S3 to start feeding the transfer paper B with the number of times m=o.

<Effects of the Invention> As described above, the present invention is provided with a sensor for detecting the sheet material fed by the feeding means and measuring the feeding time. By measuring, it is possible to detect a decrease in the feeding ability of the feeding means.

Further, since a control means is provided for controlling the driving speed of the feeding means according to the number of times the time measured by the sensor exceeds a threshold value, the driving speed of the feeding means is set again according to a decrease in feeding capacity. By doing so, the sheet material feeding operation can be maintained.

Therefore, it is possible to prevent further progress of feeding defects due to a decrease in the feeding capacity of the sheet material feeding means.

In addition, when the control means includes a display means for externally displaying changes in the driving speed of the feeding means, it is possible to monitor a decrease in the sheet material feeding ability of the feeding means one by one, It is possible to accurately notify a service person of the maintenance period for the feeding means according to the rate of decrease in the feeding speed.

Furthermore, when a plurality of feeding means are provided, only the feeding means whose feeding capacity has decreased can be displayed and replaced, thereby improving work efficiency and reducing costs.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional explanatory diagram of a sheet material feeding device, FIG. 2 is an explanatory diagram showing a schematic configuration of a copying machine to which the sheet material feeding device is applied, and FIG. 3 is a control system of the sheet material feeding device. The block diagram of FIG. 4 is a flowchart showing its operation. A is a document, B is a transfer paper, 1 is an automatic document feeder, 2 is an optical system, 3 is an image forming unit, 4 is a cassette, 5 is a paper deck, 6 is a sheet material feeding means, 7 is a pickup roller, 8 The feeding roller 9 is a registration roller, l
O is a conveying device, 11 is a fixing device, 12 is a paper ejection roller, 1
3 is a paper output tray, 14 is a belt, 15 is a motor, 16
．． 19 is a temporary guide, 18 is a paper detection sensor, 20 is a control unit, 20a is a CPU, 20b is a ROM, and 20c is a RAM
, 21 is an interface, 22 is an operating section, 23 is a motor driver, 24 is a feeding motor, 25 is a registration drive motor, and 26 is a display section.

Claims (2)

[Claims] (1) A feeding means for feeding the sheet material, a sensor for detecting the sheet material fed by the feeding means and measuring the feeding time, and a threshold value of the time measured by the sensor. A control means for controlling the driving speed of the feeding means according to the number of times the sheet material feeding device exceeds the number of times the feeding speed is exceeded. (2) The sheet material feeding apparatus according to claim 1, wherein the control means includes display means for externally displaying changes in the driving speed of the feeding means.