JPH11334935A - Sheet feeder and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To change the number of sheet feeding retries according to conditions so as to dispense with unnecessary jam processing in a sheet feeder, in which several sheet feeding retries are carried out when a sheet fed from its sheet loading means with its sheet feeding means is not detected within a prescribed time by its sheet detecting means disposed on the way of a feeding path. SOLUTION: In this sheet feeder, a sheet fed from a sheet loading means with sheet feeding means 110, 111 is detected by sheet detecting means 115, 117 on the way of a sheet feeding path, while a sheet feeding retry is carried out just after a lapsed time from a feeding start time of the feeding means 110, 111 to a sheet detecting time of the sheet detecting means 115, 117 exceeds a prescribed time. The sheet feeder is provided with a retry number setting means in which the number of sheet feeding retries can be arbitrarily set according to a wear state of the feeding means 119, 111 and so forth, while the sheet feeder determines jam generation when the sheet feeding retries are carried out to the set number of the retry number setting means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for feeding sheets stacked on sheet stacking means such as a cassette or a tray.
A sheet feeding device that performs a plurality of sheet feeding operations to remedy a jam that occurs due to a pick-up error or the like, and a printer, a copying machine, which forms an image on a sheet fed by the sheet feeding device; The present invention relates to an image forming apparatus such as a facsimile.

[0002]

2. Description of the Related Art In the prior art, a laser beam printer as an image forming apparatus is taken as an example, and FIG.
The description will be made with reference to FIG. The laser beam printer has a configuration as shown in FIG.
01 is a photosensitive drum as an electrostatic image carrier, 102 is a semiconductor laser as a light source, 103 is a scanner motor 104
Rotating polygon mirror 105, semiconductor laser 1
02 is a laser beam that scans the photosensitive drum 101 rotating in the clockwise direction in the figure and forms a latent image on the photosensitive drum by electrophotography.

Reference numeral 106 denotes a charging roller for uniformly charging the photosensitive drum 101, and 107 denotes a photosensitive drum 101.
Developing means for developing the electrostatic latent image formed thereon with toner as a developer. Reference numeral 108 denotes a roller as a transfer unit that transfers the toner image developed by the developing unit 107 onto a recording sheet as a sheet, and reference numeral 109 denotes a roller as a fixing unit that fuses the toner transferred to the sheet by heat. is there.

[0004] Reference numeral 110 denotes a cassette feed roller for feeding paper from a cassette having a function of identifying the size of recording paper as a sheet by rotating once, and feeding the paper to a conveyance path. Reference numeral 111 denotes a function of identifying the size of recording paper. This is a manual paper feed roller that feeds a sheet to a transport path from a manual paper feed port that does not have a paper feed roller. A transport roller 114 transports the paper fed from the cassette. The cassette as the sheet stacking means and the manual sheet feeding port can stack at least one sheet such as paper.

Reference numeral 115 denotes a pre-feed sensor for detecting the leading edge and the trailing edge of the fed paper. 116 denotes a pre-transfer roller for feeding the transported paper to the photosensitive drum 101.
Reference numeral 17 denotes a top for synchronizing image writing (recording / printing) on the photosensitive drum 101 and feeding of the fed paper and measuring the length of the fed paper in the feeding direction. It is a sensor. Reference numeral 118 denotes a discharge sensor for detecting the presence or absence of a sheet after fixing, and reference numeral 119 denotes a discharge roller for discharging the sheet after fixing outside the apparatus.

FIG. 2 is a block diagram of a circuit configuration of a control system for controlling such a mechanism. In FIG.
Reference numeral 201 denotes a printer controller for expanding image code data sent from an external device such as a host computer (not shown) into bit data necessary for printing by a printer, reading information inside the printer, and displaying the read information.

Reference numeral 202 denotes a printer engine control unit for controlling the operation of each unit of the printer engine in accordance with an instruction from the printer controller 201 and for notifying the printer controller 201 of printer internal information. 2
Reference numeral 03 denotes a paper transport control unit that drives / stops a motor and rollers for recording paper transport in accordance with an instruction from the printer engine control unit 202. Engine control unit 2
02 is a high-pressure control unit performed according to the instruction of 02. 205
Reference numeral denotes an optical system control unit that controls driving / stop of the scanner motor 104 and lighting of the laser beam in accordance with an instruction from the engine control unit 202. Reference numeral 207 denotes a fixing temperature control unit for adjusting the temperature of the fixing unit to a temperature designated by the printer engine control unit 202.

A sheet feeding operation from a cassette capable of recognizing a sheet size is performed by pushing a predetermined number or less of sheets of paper into a conveying path by a separation claw (112) with the rotation of a sheet feeding roller 110 as a sheet feeding means. In step (113), control is performed to separate only one sheet of paper extruded from the separation claw and send it to the transport path.

In the paper feeding operation, the paper feeding roller 110
Within a predetermined time from the start of rotation of the
If the paper feed roller 15 cannot detect the leading end of the paper feed, the paper feed operation described above (with the rotation of the paper feed roller 110, the separation claw (112) pushes a predetermined number or less of paper into the conveyance path, and the retard roller ( In step 113), only one sheet extruded from the separation claw is separated and sent to the transport path.
If the pre-feed sensor 115 cannot detect the leading edge of the paper sheet within a predetermined time after the second rotation of the paper feed roller 110, it is determined that a paper feed delay has occurred and the paper feed operation is interrupted.

In the manual sheet feeding operation which does not have the function of identifying the size of the recording sheet, the manually fed roller 111 is continuously rotated twice to feed the stacked paper to the pre-transfer roller 116.

In this paper feeding operation, when the top sensor 117 cannot detect the leading edge of the fed paper within a predetermined time from the start of the first rotation of the manual paper feed roller 111 as the paper feeding means, the above-described operation is repeated. A paper feeding operation (the stacked paper is fed to the pre-transfer roller 116 by continuously rotating the manual paper feeding roller 111 twice) is performed. If the top sensor 117 cannot detect the leading edge of the paper within a predetermined time from the start of the second paper feeding operation (the start of the third rotation of the paper feeding roller), it is determined that a paper feed delay has occurred and the paper feeding operation is interrupted. .

If the top sensor 117 detects the leading edge of the sheet before the fourth rotation of the manual feed roller 111 in the second sheet feeding operation, it is determined that the sheet feeding operation has been completed normally. The operation of the fourth rotation of the feed roller is not performed.

As described above, both the cassette having the function of identifying the size of the recording paper and the manual paper feed port having no function of identifying the size of the recording paper can cause a pickup error or the like by performing the paper feeding operation a plurality of times. The number of occurrences of the paper feed delay jam caused by the cause has been greatly reduced.

[0014]

However, in the paper feed control of the solid image forming apparatus in the above-mentioned conventional example, the number of retries performed to remedy the paper feed delay jam is fixed. When a sheet of a different type is used, or when the life of the paper feed roller is approaching, the rescue ability of the paper feed delay jam varies due to a friction coefficient of the paper feed or a worn state of the paper feed roller.

[0015] The present invention solves the above problems,
A sheet feeding apparatus and an image forming apparatus in which the number of retries is arbitrarily set in accordance with the state of a sheet feeding roller and the likelihood of jam occurrence is determined after executing the retry up to the number of times. The purpose is to provide.

[0016]

In order to achieve the above-mentioned object, a means according to the present invention is to feed a sheet from a sheet stacking means for stacking sheets by a sheet feeding means, and to feed the fed sheet on a conveying path. In a sheet feeding apparatus that performs sheet feeding retry when a time period from the start of sheet feeding by the sheet feeding unit to the detection of a sheet by the sheet detecting unit exceeds a predetermined time period. And a retry number setting means capable of arbitrarily setting the number of retry times, wherein retry can be executed up to the set number of times by the retry number setting means.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) An embodiment of an image forming apparatus provided with a sheet feeding control device for a sheet to which the present invention is applied will be described below with reference to the drawings. FIG.
1 is a schematic diagram of an image forming apparatus having a sheet feeding apparatus according to the present invention, and FIG. 2 is a block diagram showing a circuit configuration of a control system of the image forming apparatus. Since the description has been made in the conventional example, detailed description is omitted in the present embodiment and the second and third embodiments.

A control sequence of the sheet feeding apparatus according to the present invention will be described with reference to FIG. This is the engine control unit 2
Reference numeral 02 denotes a sequence when a sheet feeding operation is performed according to an instruction from the printer controller 201. In FIG. 3, S
Upon detecting a request from the printer controller 201, the counter 301 sets a retry execution counter to 0 in S302, and starts a predetermined sheet feeding operation in S303. This paper feeding operation is different from that of a cassette having a function of identifying the size of paper to be fed, and of a manual paper feed port having no function of identifying the size of recording paper. In the case of a cassette, the paper feed roller 110 is rotated once, and at the same time, a predetermined number of sheets or less are extruded into the conveyance path by the separation claw 112 and the FR roller 113 is pressed.
Control is performed to separate only one sheet of paper extruded from the separation claw and send the separated sheet to the transport path. On the other hand, in the paper feeding operation of the manual paper feeding port, control is performed such that the manual paper feeding roller 111 is continuously rotated twice to feed the paper stacked on the tray to the pre-transfer roller 116.

At the same time as the start of the sheet feeding operation in step 303,
To start a timer for detecting a paper feed delay jam. The paper feed delay jam detection time differs depending on the cassette and the manual paper feed port, and a time corresponding to each paper feed port is set.

In step S305, completion of the sheet feeding operation is detected. Completion of the paper feeding operation differs for each paper feeding port. In the case of a cassette having a function of identifying the size of the recording paper, the pre-feed sensor 115 located upstream of the top sensor 117 in the sheet conveyance direction detects the leading edge of the paper, and has a function of identifying the size of the recording paper. In the case of a manual sheet feeding port that does not have the sheet feeding operation, the sheet feeding operation is completed when the top sensor 117 located downstream of the pre-feed sensor 115 in the sheet conveyance direction detects the leading edge of the sheet. The detection of the completion of the sheet feeding operation in S305 is performed until the operation of the sheet feeding delay jam detection timer ends in S306.

If the completion of the sheet feeding operation cannot be detected in step S305 even if the sheet delay jam detection timer expires in step S306, the retry setting counter is compared with the retry execution count in step S307. The retry setting counter is a counter that stores a value that presets how many times the retry operation is performed. When the number of retry executions is smaller than the value (number of times) of the preset retry setting counter, S
At 308, the retry execution counter is incremented, and the paper feeding operation performed so far is performed again from S303. In the present invention, the set value (the number of times) of the retry setting counter can be set to an arbitrary value larger than two, as in the conventional case. This optional setting can be executed based on the wear state of the paper feed roller itself and the determination of the paper feed state such as the increase in the number of fed or fed sheets or the occurrence of jams.

The paper feeding operation from S303 to S308 is repeated several times. If the condition of retry frequency counter> retry execution frequency counter is not satisfied in S307, it is determined that a paper feed delay jam has occurred and the paper feeding operation is interrupted. I do. Then, the retry setting counter is incremented. At this time, an upper limit may be set so as not to exceed the upper limit. When the upper limit is reached, it is determined that the wear of the sheet feeding roller has reached the limit, and the printer controller 201
May report a life warning.

When the completion of the sheet feeding operation is detected in S305, it is determined that the operation is normally completed in S310. At this time, the retry execution count is checked, and the retry execution counter +
If the relationship N <retry setting counter is satisfied, the retry setting counter is decremented. N in the above condition represents the number of times, and there is no problem if it is set to any number as long as it is one or more. Alternatively, the number of executions of S301 may be counted, and the retry setting counter may be decremented when the number of retries is equal to or less than a predetermined number.

According to the present embodiment as described above,
It is determined that a jam has occurred when a retry is performed until the value of a retry setting counter arbitrarily set according to the wear state of the paper feed roller or the like is reached. The jam occurrence rate can be reduced as compared with the case where the retry is executed up to the retry set value and the jam is determined. Therefore, the reliability of the sheet feeding apparatus and the image forming apparatus equipped with the sheet feeding apparatus can be improved, and unnecessary jam processing can be eliminated, and the operability and usability can be improved.

(Embodiment 2) A control sequence of the sheet feeding apparatus according to the present invention will be described with reference to FIG. This is a sequence in a case where the engine control unit 202 is designated by the printer controller 201 as a manual paper feed port having no function of identifying the paper feed port and the paper feed port, and performs a paper feed operation in accordance with a print request instruction. In FIG. 4, when the engine control unit 202 detects a print request from the printer controller 201 in S401, the retry execution counter is set to 0 in S402, and the manual feed roller 111 is continuously rotated two times in S403 to set the tray. A sheet feeding operation for feeding the sheets stacked on the pre-transfer roller 116 is performed. Also, 303
At the same time as the start of the paper feed operation, a timer for detecting a paper feed delay jam is started in S404.

In step S405, completion of the sheet feeding operation is detected. Completion of the paper feeding operation is determined by the top sensor 117 detecting the leading edge of the paper. The paper feeding operation is completed. The detection of the completion of the paper feeding operation in S405 is performed until the operation of the paper feeding delay jam detection timer ends in S407.

If the paper feed operation is completed in S405, that is, if the top sensor 117 detects the leading edge of the paper fed and conveyed by the manual paper feed roller 111, it is determined in S406 that the paper feed operation has been completed normally. The paper feeding operation ends.

If the completion of the sheet feeding operation cannot be detected in step S405 even if the sheet feeding delay jam detection timer expires in step S407 and the sheet feeding operation is completed, the number of retry execution times is set to N in step S408. To determine if it has been reached. N
If the number of times has not been reached, the retry execution counter is incremented in S409, and the sheet feeding operation is performed again from S403.

If it is detected in S408 that the number of retry executions has reached N, the pre-feed sensor 115 detects the leading edge of the paper fed by the manual paper feed roller 111 in S410. Performs the sheet feeding operation 2 described below. Conversely, when the leading edge of the sheet is not detected by the pre-feed sensor 115, it is determined in S416 that a paper feed delay has occurred.

In the paper feed operation 2, the manual paper feed roller 111 performs two rotations, which is normally performed in the manual paper feed opening paper feed operation, but only one rotation. The paper feed delay jam detection time is optimized accordingly. This control is possible because the distance from the pre-feed sensor 115 to the top sensor 117 is a distance that can be conveyed by one rotation of the manual paper feed roller.

In step S411, the manual feed roller 111 is set to 1
Rotate. At the same time, a timer operation for detecting a paper feed delay jam is started in S412. The timer data at this time may be the same as the data set in S404 and may be different. After that, in step S413, completion of the sheet feeding operation is detected. This is performed until the operation end of the jam detection timer is detected in S414. Completion of the paper feeding operation performed in S141 is determined by S
Similarly to 405, the top sensor 117 detects that the manual feed roller detects the leading end of the paper fed.

If the top sensor 117 detects the leading edge of the sheet in step S413, it is determined that the sheet feeding operation has been completed normally. If the top sensor 117 does not detect the leading edge of the sheet in S413 before the expiration of the sheet delay jam detection timer in S414, it is determined that a sheet delay jam has occurred and the sheet feeding operation is interrupted.

As described above, in the present embodiment, when the predetermined retry operation is completed and the paper is conveyed halfway through the paper conveyance path, the manual feed roller is rotated once again to cause a paper feed jam. To relieve the occurrence of At this time, the sheet feeding operation is different from the normal sheet feeding operation (retry operation). However, the same sheet feeding operation as the normal sheet feeding operation may be performed. It may be performed between S407 and S408.

(Embodiment 3) A control sequence of the sheet feeding apparatus according to the present invention will be described with reference to FIG. This is a sequence in a case where the engine control unit 202 performs a sheet feeding operation according to an instruction from the printer controller 201. In FIG. 5, when detecting a request from the printer controller 201 in S501, the retry execution counter is set to 0 in S502, and the retry setting number is set in S503. The number of retry settings is determined by the printer controller 2
01, each high-voltage output condition of the electrophotographic process,
Set according to the fixing conditions. In the image forming apparatus described in the present embodiment, the rough paper mode and the OH
There is a T mode. The rough paper mode is a mode in which printing is performed on thick paper, and the fixing temperature is adjusted to a predetermined temperature higher than a normal time when no specification is made.
The HT mode is a mode in which it is assumed that OHP is passed, and the fixing temperature is lowered by a predetermined temperature as compared with the case where no mode is specified, and the temperature is adjusted. In both temperature control modes, cardboard, OH
Paper feeding conditions such as P are also strict.

Therefore, in S503, the number of retries is set to N when no mode is specified, and N + α when the rough paper mode and the OHT mode are specified.

In step S504, a predetermined sheet feeding operation is started. This paper feeding operation is different in operation from a cassette having a function of identifying the size of paper to be fed and a manual paper feed port having no function of identifying the size of recording paper. In the case of a cassette, the separation claw 1
At step 12, a predetermined number of sheets or less of paper are extruded into the conveyance path, and the FR roller 113 controls to separate only one sheet of paper extruded from the separation claw and feed the separated sheet onto the conveyance path. On the other hand, in the paper feeding operation of the manual paper feeding port, control is performed such that the manual paper feeding roller 111 is continuously rotated twice to feed the paper stacked on the tray to the pre-transfer roller 116.

Simultaneously with the start of the paper feeding operation in S504,
At 5, the timer for detecting the paper feed delay jam is started. The paper feed delay jam detection time differs depending on the cassette and the manual paper feed port, and a time corresponding to each paper feed port is set.

In step S506, completion of the sheet feeding operation is detected. Completion of the paper feeding operation differs for each paper feeding port. In the case of a cassette having a function of identifying the size of recording paper, the pre-feed sensor 115 detects the leading edge of the paper. When the sensor 117 detects the leading edge of the paper,
The paper feeding operation is completed. The detection of the completion of the paper feed operation in S506 is performed until the operation of the paper feed delay jam detection timer ends in S507.

If the completion of the paper feeding operation cannot be detected in S506 even if the paper feeding delay jam detection timer expires in S507 and the paper feeding operation is completed, the retry setting counter is compared with the number of retry executions in S509. . The retry setting counter is a counter that stores a value that presets how many times the retry operation is performed. Retry execution count is
This preset retry setting counter value (number of times)
If smaller, the retry execution counter is incremented in S509, and the paper feeding operation performed so far is repeated from S504.

The paper feeding operation from S504 to S510 is repeated several times. If the condition of the retry number counter> the retry execution number counter is not satisfied in S307, it is determined that the paper feeding is delayed and the paper feeding operation is interrupted. I do.

When the completion of the paper feeding operation is detected in S506, it is determined in S508 that the operation is normally completed.

[0042]

As described above, according to the present invention,
The number of retries is set arbitrarily according to the type of paper to be fed, the feeding state, and the worn state of the feed roller, and the retry is executed up to the set number of times. To improve the reliability of the sheet feeding apparatus and the image forming apparatus,
Usability can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic view of an embodiment of an image forming apparatus including a sheet feeding device according to the present invention.

FIG. 2 is a block diagram illustrating a circuit configuration of a control system of the image forming apparatus.

FIG. 3 is a flowchart illustrating a sheet feeding operation by a control system according to the embodiment of the present invention.

FIG. 4 is a flowchart showing a sheet feeding operation by a control system according to a second embodiment of the present invention.

FIG. 5 is a flowchart illustrating a sheet feeding operation by a control system according to a third embodiment of the present invention.

[Description of Reference Numerals] 101 photoconductor drum 102 semiconductor laser 107 developing unit 108 transfer roller 109 fixing unit 110 cassette feed roller 111 manual feed roller 113 FR roller 114 transport roller 116 before transfer Roller 115: Pre-feed sensor 117: Top sensor

Claims (6)

[Claims] 1. A sheet is fed from a sheet stacking means for stacking sheets by a sheet feeding means, a sheet to be fed is detected by a sheet detecting means on a conveyance path, and the sheet detecting means is started from the start of feeding of the sheet feeding means. In a sheet feeding apparatus that executes a sheet retry when the time until a sheet is detected by a predetermined time exceeds a predetermined time, the sheet feeding apparatus includes a retry number setting unit capable of arbitrarily setting a retry number. A sheet feeding device wherein retry can be performed up to a set number of times by a number setting means. 2. A sheet stacking unit for stacking sheets, a sheet feeding unit for feeding sheets one by one from the sheet stacking unit, and a sheet detection unit for detecting a sheet fed by the sheet feeding unit on a conveyance path. Means, scheduled time setting means for setting a scheduled time from the start of sheet feeding by the sheet feeding means to the arrival of a sheet at the sheet detecting means, and a sheet leading end by the sheet detecting means from the start of sheet feeding by the sheet feeding means. Time-measuring means for measuring the time until detection; sheet-feeding failure judging means for judging a sheet-feed failure when the time measured by the time-measuring means exceeds the time set by the required time setting means; A retry control means for performing a paper feeding operation again when the paper feeding defect is determined by the means; and a retry number setting means capable of arbitrarily setting a retry execution number. A sheet feeding device capable of executing up to a set number of tries. 3. The apparatus according to claim 1, wherein at least two sheet detecting means are provided, and when a sheet is not detected within a predetermined time by a sheet detecting means located downstream in the sheet conveying direction, the sheet detecting means is disposed upstream in the sheet conveying direction. A sheet feeding device, wherein a retry is executed when a sheet is not detected even by a sheet detecting unit located. 4. The sheet feeding apparatus according to claim 1, wherein the setting of the retry number setting unit is changed according to a wear state of the sheet feeding unit. 5. An image forming apparatus comprising: the sheet feeding device according to claim 1; and image forming means for forming an image on a sheet fed by the sheet feeding device. 6. The image forming unit according to claim 5, wherein the image forming unit includes an engine control unit that executes an electrophotographic process and performs a printing operation, and a printer controller that instructs the engine control unit on the process conditions of the electrophotography. An image forming apparatus, wherein the number of retries set by the retry number setting means is changed in accordance with a process condition specified by the printer controller.