JPH08169632A - Paper feeder - Google Patents

Abstract

PURPOSE: To enable it to control the refeed of paper without entailing any drop in the whole print speed as well as to improve the certainty of conveyance to the slippage or the like of a paper feed roller. CONSTITUTION: At the time of feeding a sheet of paper from a paper feeding port of a cassette, in the case where paper feeding fails to do with the first time control, speed of a driving motor 3 of a paper feed roller 7 should be set to be higher than the normal speed in time of controlling the refeed of paper (retry control), and further jam vibro-timing is set to be earlier than the normal control, and thereby a speed of paper conveyance is enhanced. In addition, c.w or c.c.w rotation of the paper feed roller 7 is repeated and vibration is imparted to it, or a direct vibration is imparted to recording paper by means of cam drive or the like otherwise, through which the extent of certainty in paper feeding at the time of the retry control is secured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeding device, and more particularly to control for reducing a jam of a paper feeding mechanism for a recording medium (for example, recording paper) in an image forming apparatus such as a copying machine or a printer.

[0002]

2. Description of the Related Art Conventionally, in the paper feed control of this type of image forming apparatus, the time management from the start of paper feed to the means for recognizing that the recording paper has been fed (for example, a paper feed sensor) is fixed at a prescribed level. The value is set, and if it is not recognized even after this time has passed, it is regarded as a paper feed delay jam (paper jam). The cause of this jam is friction of the recording paper, slippage, abrasion of the rollers of the paper feed mechanism, etc., and the paper feed control (retry) is performed again for the jam caused by this paper feed delay, so that the jam is not canceled. It is possible to continue the operation by returning to. At this time, the same paper feeding control (retry) is repeated.

[0003]

However, as described above, when the same control is repeated, the paper feed is often delayed again due to the same cause. Further, there is a problem in that a time lag occurs, the overall printing speed is reduced, and the printing performance is greatly reduced.

The present invention has been made in view of the above points, and an object of the present invention is to perform refeed control without reducing the overall printing speed, or to prevent the feed roller from slipping. To provide a paper feeding device capable of increasing the certainty of conveyance for a paper feeding failure due to a paper feed or poor quality paper, and further promoting separation of a plurality of recording papers to increase the certainty of paper feeding at the time of retry. is there.

[0005]

To achieve the above object, the present invention provides a paper feed control again when paper cannot be fed by the first control when feeding a recording medium from a paper feed port. In the paper feeding apparatus for carrying out the above, it is provided with a control means for setting the paper feeding speed at the time of the paper feeding control again and making the time for judging the paper feeding delay earlier than at the time of the normal paper feeding operation. To do.

Further, the present invention is preferably, in another form, a paper feeding apparatus for performing paper feeding control again when paper feeding cannot be performed by the first control when feeding paper from a paper feeding port. It is possible to further comprise a control means for setting the paper feed control speed at the time of the paper feed control again to be lower than that at the normal paper feed operation and delaying the time to judge the paper feed delay.

Further, in another aspect of the present invention, preferably, in the second paper feeding control, the paper feeding roller for feeding paper from the paper feeding port repeats forward and reverse rotation for a predetermined time. It can be characterized in that it comprises a control means.

Further, in another aspect of the present invention, preferably, when the paper feed control is performed again, the paper feed roller is driven so as to vibrate the paper feed roller for feeding paper from the paper feed port. It can be characterized in that it is provided with a second control means for stepping out the pulse motor.

Further, according to another aspect of the present invention, preferably, a vibrating mechanism for directly vibrating a recording medium in the vicinity of the sheet feeding port and driving the vibrating mechanism during the feeding control again. And a second control means for performing the operation.

Further, the present invention is preferably, in another form, a measuring means for measuring a paper feeding time in which a recording medium is fed from the paper feeding port, and the following according to the measurement result of the measuring means. It can be characterized by comprising a time adjusting means for adjusting a time for determining a paper feed delay during a paper feed operation.

[0011]

In the present invention, when paper is fed from the paper feed port,
If the paper feeding cannot be performed by the second control, the paper feeding control (retry control) is performed again, and at the time of the two-stage re-feeding control (at the time of retry), the second-stage re-feeding different from the first-stage paper feeding control is performed. By varying the paper feed / conveyance speed of the recording paper by the paper control, the paper feed / conveyance speed at the time of retry is increased so that the overall printing speed can be maintained.

Further, by lowering the sheet feeding / conveying speed at the time of retry, it is possible to increase the certainty of the sheet feeding due to the slip of the sheet feeding roller, the feeding failure due to the settling, and the poor quality paper.

Paper feed control capable of forward / reverse inversion drive is performed,
Alternatively, by providing a vibration mechanism that promotes separation of a plurality of recording papers, the separation of the plurality of recording papers is facilitated and the reliability of paper feeding at the time of retry is increased.

Further, the reliability of the above-mentioned paper feed control can be increased by making the time for judging the paper feed delay variable.

Further, by changing the time for judging the paper feed delay in response to the change of the paper feed time with time, the change of the paper feed timing due to the change of paper feed roller due to wear or abrasion is managed. While it is possible to control the paper feed.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 shows the structure of a paper feed mechanism in an image forming apparatus according to the first embodiment of the present invention. FIG.
Then, a case of a laser printer is shown as an example of the image forming apparatus. The configuration and operation will be described below with reference to FIG.

The laser printer main body (hereinafter referred to as the main body) has a cassette 6 for accommodating the recording paper S, and a paper feed roller (pickup roller 7 and paper feed / conveyance roller pair 9) for feeding the recording paper S from the cassette 6. Are configured). A pair of registration rollers (not shown) that synchronously conveys the recording paper S is provided downstream of the paper feed rollers 7 and 9, and further downstream is provided with an image forming unit of a known electrophotographic process (not shown). ) Is provided.

Reference numeral 1 denotes a printer device for controlling the main body, which includes a timer, a ROM (read only memory), and a RAM.
It is composed of a CPU (microcomputer) incorporating a (random access memory) and the like, various input / output control circuits (not shown), etc., and stores a control program described later shown in FIGS. 2 to 5 in the ROM. . The printer control device 1 also controls the drive and drive speed of the motor 3 via a motor driver (motor drive circuit) 2. For example, the drive speed of the pulse motor as the motor 3 is changed by a pulse signal, and the forward / reverse rotation is switched. The drive of the paper feed rollers 7 and 9 is given by this motor 3. Reference numeral 5 is a display device, and 4 is a DC (direct current) power supply.

The flowchart of FIG. 2 shows the procedure of paper feed control management in the first embodiment of the present invention. When it is determined to start feeding the paper (step 401), the subsequent processing is performed. That is, if the sheet is not the sheet fed at the time of retry but is the sheet fed at the normal time, the speed of the pulse motor 3 and the jam detection timing are set to those at the ordinary time. (Steps 402-4)
04).

If the sheet is fed at the time of retry, the pulse motor 3
Is set to a higher speed than usual and the jam detection timing is set to be earlier than normal (steps 402, 405, 4).
06).

Thereafter, the paper feed control including jam detection and the like is started (step 407).

Subsequently, the end of the paper feed control until the loop formation of the recording paper S is waited, but if the jam detection timing is reached before the paper feed control is completed, the jam processing is performed (steps 408 to 410). When the paper feed control is completed, the process returns to the first step (step 409).

As described above, the image formation can be performed without decreasing the overall print speed by increasing the paper feed / transport speed during the refeed control (retry).

(Second Embodiment) The flowchart of FIG.
6 shows a procedure of paper feed control management in the second embodiment of the present invention. The paper feeding mechanism of this example is similar to that of FIG. The same processing steps as those in FIG. 2 of the first embodiment are designated by the same numbers. Only different processing will be described. If the sheet is fed at the time of retry (step 402), the speed of the pulse motor 3 is set to be lower than the normal time and the jam detection timing is set to be slower than the normal time (steps 415 and 416).

As described above, by lowering the feeding / conveying speed at the time of retry, it is possible to increase the certainty of the feeding for the feeding failure due to the slip of the feeding roller, the feeding failure, and the poor quality paper.

(Third Embodiment) The flowchart of FIG.
9 shows a procedure of paper feed control management in the third embodiment of the present invention. The paper feeding mechanism of this example is similar to that of FIG. The same processing steps as those in FIG. 2 of the first embodiment are designated by the same numbers.

First, in step 401, the process waits until the paper feed starts. When the sheet feeding is started, it is determined whether the sheet feeding is a retry (step 402). If the sheet feeding is not a retry, the sheet feeding control including the jam detection and the like is started (step 407). Then, the feeding is completed (step 4
09) and the jam detection timing (step 408) are monitored. If the jam detection timing comes before the paper feed is completed, jam processing is performed (step 410) and the paper feed control is completed.

On the other hand, if the sheet feeding is retried in step 402, the timer T ₀ is reset and started (step 5
01), the pulse motor 3 for driving the pickup roller 7 is normally rotated by one pulse (step 502), and a wait time of T ₂ seconds is provided so as not to get out of step (step 50).
3), reverse the pulse motor 3 by one pulse (step 50
4) Similarly, a wait time of T ₂ seconds is set (step 505).

If the timer T ₀ has reached the predetermined time T ₁ (step 506), the paper feed control is started (step 407). If the timer T ₀ has not reached the predetermined time T ₁ , steps 502 to 505 are performed. The above normal / reverse operation is repeated (step 407). After that, the paper feed control is started.

As described above, by rotating the paper feed pickup roller 7 in the normal and reverse directions during the paper feed retry, the recording paper is squeezed without any new mechanism, the separation between the recording papers is improved, and the re-feeding operation is performed. It can be done well.

(Fourth Embodiment) The flowchart of FIG.
9 shows a procedure of paper feed control management in the fourth embodiment of the present invention. The paper feeding mechanism of this example is similar to that of FIG. Further, the same processing steps as those in FIG. 2 of the present embodiment are designated by the same reference numerals.

First, in step 401, the process waits until the paper feed starts. When the sheet feeding is started, it is determined whether the sheet feeding is a retry (step 402). If the sheet feeding is not a retry, the sheet feeding control including the jam detection and the like is started (step 407). Then, the feeding is completed (step 4
09) and jam detection timing (step 408) are monitored, and if jam detection timing occurs before paper feeding is completed, jam processing is performed (step 410) and paper feeding control is completed.

On the other hand, if the paper feed is retried in step 402, the timer T ₀ is reset and started (step 6
01), the pulse motor 3 for driving the pickup roller 7 is normally rotated by one pulse (step 306).

If the timer T ₀ has reached the predetermined time T ₁ (step 603), the paper feed control is started (step 407), and if the timer T ₀ has not reached the predetermined time T ₁ (step 603). The normal rotation operation of step 602 is repeated. By repeating this forward rotation operation continuously in units of one pulse, the pulse motor 3 loses step and the pickup roller 7 vibrates without the recording paper being conveyed while the torque is being applied to the motor by the recording paper. . Then, the paper feed control is started (step 407).

As described above, the pulse motor 3 that drives the paper feed pickup roller 7 when the paper feed is retried.
By vibrating the pick-up roller 7 and vibrating the pickup roller 7, the recording paper can be vibrated without providing a new mechanism, the separation between the recording papers can be improved, and the re-feeding operation can be favorably performed.

(Fifth Embodiment) FIG. 6 shows the construction of a paper feed mechanism in an image forming apparatus according to a fifth embodiment of the present invention. FIG.
The difference from the configuration of the first embodiment is that the cam 12 pushes up the recording sheet S from below by rotating, the flag 13 that rotates in conjunction with this cam 12, and the cam 12 does not push the recording sheet S. A photo interrupter 14 for detecting a state (hereinafter referred to as a home position) via a flag 13, a stepping motor 11 for rotating the cam 12, and a motor driver 10 for driving the stepping motor 11. Is further provided. The flag 13 is formed in a plate shape so as to shield the photo interrupter 14 from light in the home position state, and a signal from the photo interrupter 14 is sent to the printer control device 1 that controls the main body.

Next, the control procedure of this embodiment will be described with reference to the flowchart of FIG. First, in step 401, the process waits until the paper feed starts. When the paper feed is started, it is judged whether or not the paper feed is retried (step 40).
2) If it is not a paper feed retry, paper feed control including jam detection and the like is started (step 407). Subsequently, the paper feed completion (step 409) and the jam detection timing (step 408) are monitored, and if the jam detection timing comes before the paper feed is completed, the jam processing is performed (step 4
10) The paper feed control is completed.

On the other hand, if the paper feed is retried in step 402, the timer T ₀ is reset and started (step 70).
1), a stepping motor 1 for driving the cam 12 of FIG.
1 is rotated (step 702).

After continuing to rotate the stepping motor 11 until the timer T ₀ reaches the predetermined time T ₁ (step 70)
3) In order to return the cam 12 to the home position, wait until the photo interrupter 14 as a sensor is shielded by the flag 13 (step 704), and stop the stepping motor 11 (step 705). Then, the paper feed control is started (step 407).

As described above, when the recording sheet is vibrated directly by the cam drive during the sheet feeding retry,
The separation between the recording sheets can be improved, and the refeed operation can be favorably performed.

In the present embodiment, the cam drive is exemplified as the means for directly applying the vibration to the recording paper, but in addition to this, known vibration means such as an electromagnetic vibrator or an ultrasonic vibrator can be used. . Further, the effect can be expected even if the paper feed pickup roller 7 is vibrated by using these vibrators.

(Sixth Embodiment) Next, a sixth embodiment of the present invention will be described with reference to FIGS.

The timing chart of FIG. 8 shows the operation timing of this embodiment. The paper feeding mechanism of this example is similar to that of FIG. Paper feed motor 3 for feeding and feeding at the timing of paper feed start
The time until the paper feed sensor 8 that detects that the recording paper S that has been fed is fed is set to t, and this value t exceeds the preset value T. If this happens, there will be a jam due to a paper feed delay.

The flow chart of FIG. 9 shows the paper feed control procedure of this embodiment. The time t until the paper feed sensor 8 that recognizes that the paper is fed from the paper feed start signal is measured, and the time t is compared with a predetermined value T (step 801). The default value T is an initial value of the time for determining the paper feed delay.

If the output of the paper feed sensor 8 is not recognized by the time T, that is, if the measured value t is larger than the time T, there is a delay, and jam or re-feed (retry) control is performed (step 807).

When the output of the paper feed sensor 8 is recognized by the time T, that is, when the measured value t is smaller than the time T, the predetermined value a (a> 0: measurement value error, variation, margin) is set. (Compensated correction value) and the sum of the measured value t and the preset time T are compared (step 802), and when t + a is larger than T, the preset value T ′ (T ′> T) and t + a are further compared (step 802). 803), if t + a is larger than T ', a warning prompting the inspection of the paper feed mechanism is displayed on the display device 5 (step 804). The predetermined value T'is a paper feed delay time that prompts inspection of the mechanism.

When t + a is smaller than T'in step 803, t + a is set as a new T (step 805) and print sequence control is performed (step 806).

In step 802, t + a
If is smaller than T, the print sequence control is performed with T as it is (step 806).

As described above, by varying and managing the paper feed delay time T in accordance with the measurement time t from the start of paper feed to the detection of the paper feed sensor, the paper feed time due to the reduction of the paper feed rollers and the like is reduced. It enables control qualification in response to fluctuations.

(Other Embodiments) It is needless to say that a better synergistic effect can be obtained by appropriately combining the respective embodiments of the present invention described above.

[0052]

As described above, according to the present invention, the following effects can be obtained.

(1) When the paper is fed from the paper feed port, if the paper feed cannot be performed by the first control, the paper feed control is performed again. In the second-stage refeed control, which is different from the second-stage paper feed control, the recording paper feed / conveyance speed is made variable to increase the paper feed / conveyance speed during retry. You can do it right away.

(2) By lowering the sheet feeding / conveying speed at the time of retry, it is possible to convey even if the sheet feeding roller slips or the sheet feeding is defective due to the settling.

(3) Since the paper feed control capable of the forward / reverse reversal drive is performed or the vibration mechanism for promoting the separation of a plurality of recording papers is provided, the separation of the plurality of recording papers is promoted and the feeding at the time of retry is performed. The reliability of the paper can be increased.

(4) Since the time for judging the paper feed delay is made variable in response to the change of the paper feed time with time,
It is possible to perform the paper feed control while managing the change of the paper feed timing due to the change of the paper feed roller due to the wear or wear of the paper feed roller.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a paper feed mechanism according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a procedure of paper feed control according to the first embodiment of the present invention.

FIG. 3 is a flowchart showing a procedure of paper feed control according to a second embodiment of the present invention.

FIG. 4 is a flowchart showing a procedure of paper feed control according to a third embodiment of the present invention.

FIG. 5 is a flowchart showing a procedure of paper feed control according to a fourth embodiment of the present invention.

FIG. 6 is a block diagram showing the configuration of a paper feed mechanism of a fifth embodiment of the present invention.

FIG. 7 is a flowchart showing a procedure of paper feed control according to a fifth embodiment of the present invention.

FIG. 8 is a timing chart showing a paper feed timing according to a sixth embodiment of the present invention.

FIG. 9 is a flowchart showing a procedure of paper feed control according to a sixth embodiment of the present invention.

[Explanation of symbols]

 1 control device 2, 10 motor driver 3 motor for giving driving force to paper feed roller 5 display device 6 cassette 7 paper feed roller (pickup roller) 8 paper feed sensor 9 paper feed roller (paper feed roller) 11 cam drive force A motor for giving 12 a cam 13 a flag 14 a photo interrupter

Claims (6)

[Claims] 1. A paper feeding device that performs paper feeding control again when paper cannot be fed by the first control when feeding a recording medium from a paper feeding port. A paper feeding device comprising a control means for setting a paper feeding / conveying speed higher than that during a paper feeding operation and setting a time for determining a paper feeding delay to be earlier. 2. A paper feeding device which performs paper feeding control again when paper feeding cannot be performed by the first control when paper is fed from a paper feeding port, wherein a normal paper feeding operation is performed during the paper feeding control again. A sheet feeding device, comprising: a control unit configured to set a sheet feeding / conveying speed lower than time and delay a time for determining a sheet feeding delay. 3. The apparatus according to claim 1, further comprising a second control unit that repeats forward and reverse rotations of a paper feed roller for feeding paper from the paper feed port during the paper feed control again. The sheet feeding device according to item 1 or 2. 4. A second control means for stepping out a pulse motor for driving the paper feed roller for vibrating the paper feed roller for feeding paper from the paper feed port during the paper feed control again. The sheet feeding device according to claim 1 or 2, further comprising: 5. A vibrating mechanism for directly vibrating the recording medium in the vicinity of the paper feed port, and a second control means for driving the vibrating mechanism during the paper feed control again. The sheet feeding device according to claim 1, wherein the sheet feeding device is a sheet feeding device. 6. A measuring unit that measures a sheet feeding time for feeding a recording medium from the sheet feeding port, and determines a sheet feeding delay in the next sheet feeding operation according to a measurement result of the measuring unit. The sheet feeding device according to claim 1, further comprising a time adjusting unit that adjusts time.