JP2007062947A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device capable of surely preventing delay in feeding respective recording sheets to be fed. <P>SOLUTION: A reaching time measuring part 111 measures a reaching time in which the recording sheet reaches to a register roller from a paper feeding roller, and a reaching time averaging part 112 averages the measured reaching time and the previously measured reaching time. An average reaching time storing part 121 stores the averaged reaching time for each fed recording sheet as an average reaching time, and a reference reaching time storing part 122 stores a reference reaching time in advance. A reaching time comparison part 133 compares the average reaching time and the reference reaching time for each fed recording sheet, and a correction part 114 corrects the action of the paper feeding part 10 for each fed recording sheet in a manner that the reaching time in which the recording paper reaches from the paper feeding roller to the register roller is identical to the reference reaching time when the average reaching time is different from the reference reaching time. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, and a multifunction machine having these functions.

  2. Description of the Related Art Conventionally, in color image forming apparatuses typified by printers, copiers (copiers), facsimile machines, and the like, a plurality of developing machines provided with toners such as cyan, magenta, yellow, and black as latent images on a photosensitive drum. Develop individually. Then, after sequentially transferring the toner images of the respective colors onto the transfer belt, the toner images are transferred to a recording sheet and fixed by a fixing device.

  In such a color tandem type image forming apparatus, the latent image production process is started prior to the paper feeding operation, and the paper feeding operation is started. Further, it is common to provide a predetermined stop time with the registration roller so that the leading edge position of the recording paper is aligned with the registration roller. This stop time is set to a time during which no jamming of the recording paper occurs in the registration roller.

  The timing for starting the paper feeding operation is fixed at the time of designing the image forming apparatus, and the stop time of the recording paper at the registration roller is ideally a constant value. However, in an actual image forming apparatus, the leading end of the paper feed cassette, the occurrence of mechanical slip between the recording paper and the roller that transports the recording paper, or the paper feed delay due to the pick-up failure by the pick-up roller etc. May occur.

As a technique for reducing the paper feed delay and the like and feeding the recording paper to the image forming unit satisfactorily, after passing the paper feed cassette, the time required to pass the specified range when the first paper is passed is obtained as a standard value. Therefore, there is a technique for correcting the rotational speed of the second and subsequent paper feed motors to feed paper (for example, see Patent Document 1).
JP 2002-356239 A

  However, in the image forming apparatus of Patent Document 1, the result of the first sheet printing process is regarded as valid data, and the second sheet and subsequent sheet printing processes are corrected. Therefore, data reliability is poor. For example, there may be variations among image forming apparatuses such that the first sheet is correctly fed but the second sheet is not correctly fed. Therefore, even if the second and subsequent sheet feeding timings are corrected from the first sheet feeding measurement, accurate correction is not always possible.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of reliably preventing a delay in feeding of each recording sheet to be fed. .

  An image forming apparatus according to the present invention includes a paper feed unit that feeds recording paper using a paper feed roller, and an arrival time measurement unit that measures an arrival time until the recording paper reaches the registration roller from the paper feed roller. , Arrival time averaging means for averaging the arrival times measured by the arrival time measuring means and the arrival times measured in the past for each recording sheet fed, and averaging by the arrival time averaging means The average arrival time storage means for storing the recorded arrival time as the average arrival time for each fed recording sheet, and the reference for preliminarily storing the reference arrival time until the recording sheet reaches the registration roller from the sheet feeding roller An arrival time storage unit, an average arrival time stored in the average arrival time storage unit, and a reference arrival time stored in the reference arrival time storage unit In comparison, if the average arrival time and the reference arrival time are different, the operation of the paper feeding unit is performed so that the arrival time until the recording paper reaches the registration roller from the paper supply roller is the same as the reference arrival time. Correction means for correcting each recording sheet fed.

  According to this configuration, the recording sheet is fed by the sheet feeding unit using the sheet feeding roller. Then, the arrival time until the recording paper reaches the registration roller from the paper feed roller is measured, and the measured arrival time and the arrival time measured in the past are averaged for each fed recording paper, The averaged arrival time is stored for each recording sheet fed as the average arrival time. A reference arrival time until the recording paper reaches the registration roller from the paper supply roller is stored in advance. Also, the average arrival time and the reference arrival time are compared for each recording sheet to be fed, and when the average arrival time and the reference arrival time are different, the arrival time until the recording sheet reaches the registration roller from the feeding roller Is corrected for each recording sheet to be fed so as to be equal to the reference arrival time.

  Therefore, the average arrival time obtained by averaging the arrival time until the recording paper reaches the registration roller from the paper feeding roller for each fed recording paper, and the reference arrival time stored in advance as normal arrival time are obtained. If the average arrival time and the reference arrival time are different from each other, the operation of the sheet feeding unit is fed so that the arrival time until the recording sheet reaches the registration roller from the sheet feeding roller is the same as the reference arrival time. Since correction is performed for each recording sheet, it is possible to reliably prevent a delay in feeding for each recording sheet to be fed.

  Even if the arrival time of each recording paper varies for each job, the measured arrival time and the arrival time measured in the past are averaged for each fed recording paper. The reliability of the average arrival time data compared with the arrival time can be improved.

  In the image forming apparatus, it is preferable that the operation of the paper feeding unit corrected by the correction unit is to adjust the rotation speed of the paper feeding roller for each recording paper fed.

  According to this configuration, the average arrival time and the reference arrival time are compared for each recording sheet to be fed, and when the average arrival time and the reference arrival time are different, the recording sheet reaches the registration roller from the feeding roller. The rotation speed of the paper feed roller is adjusted for each recording paper to be fed so that the arrival time until is the same as the reference arrival time. Therefore, when the arrival time until the recording paper reaches the registration roller from the paper feed roller is slower than the reference arrival time, the rotational speed of the paper feed roller is adjusted to be faster than a preset rotational speed. Thus, it is possible to prevent a paper feed delay for each recording paper fed.

  In the image forming apparatus, the operation of the paper feeding unit corrected by the correction unit is performed by adjusting a paper feeding timing at which the paper feeding roller feeds the recording paper for each recording paper fed. Preferably there is.

  According to this configuration, the average arrival time and the reference arrival time are compared for each recording sheet to be fed, and when the average arrival time and the reference arrival time are different, the recording sheet reaches the registration roller from the feeding roller. In order for the arrival time until the reference arrival time to be the same as the reference arrival time, the paper feed timing at which the paper feed roller feeds the recording paper is adjusted for each recording paper fed. Accordingly, when the arrival time until the recording paper reaches the registration roller from the paper feed roller is later than the reference arrival time, the paper feed timing of the paper feed roller is set to be faster than the preset paper feed timing. By adjusting for each recording sheet to be fed, it is possible to prevent a delay in feeding for each recording sheet to be fed.

  In the image forming apparatus, a correction mode setting for setting a correction mode for correcting the operation of the paper feeding unit so that the arrival time until the recording paper reaches the registration roller from the paper feeding roller is set to the reference arrival time. The correction means is stored in the average arrival time stored in the average arrival time storage means and in the reference time storage means only when the correction mode is set by the correction mode setting means. The reference arrival time is compared for each recording sheet to be fed, and when the average arrival time and the reference arrival time are different, the arrival time until the recording sheet reaches the registration roller from the sheet feeding roller is It is preferable to correct the operation of the sheet feeding unit for each recording sheet fed so as to be the same as the reference arrival time.

  According to this configuration, the average arrival time is set only when the correction mode for correcting the operation of the sheet feeding unit is set so that the arrival time until the recording sheet reaches the registration roller from the sheet feeding roller is set to the reference arrival time. And the reference arrival time are compared for each recording paper to be fed, and if the average arrival time and the reference arrival time are different, the arrival time until the recording paper reaches the registration roller from the paper feed roller is referred to as the reference arrival time. The operation of the sheet feeding means is corrected for each recording sheet to be fed so as to be the same.

  Therefore, only when the correction mode is set, the operation of the sheet feeding unit is performed for each recording sheet to be fed so that the arrival time until the recording sheet reaches the registration roller from the sheet feeding roller is the same as the reference arrival time. Therefore, normal paper feeding can be performed without setting the correction mode until a paper feed delay occurs. When a paper feed delay occurs, each recording paper fed in the correction mode is fed. The paper feeding delay can be prevented.

  The image forming apparatus may further include arrival time storage means for temporarily storing the arrival time measured by the arrival time measuring means for each fed recording sheet, and the arrival time averaging means After the job is finished, an average value of the arrival time stored in the arrival time storage means and the average arrival time stored in the average arrival time storage means is calculated for each fed recording sheet. It is preferable to do.

  According to this configuration, the measured arrival time is temporarily stored for each fed recording sheet, and after the job is finished, the temporarily stored arrival time and the stored average arrival time The average value is calculated for each recording sheet fed, so that the processing can be simplified and the processing speed of averaging can be improved rather than averaging each time the arrival time is measured. .

  According to the present invention, the arrival time until the recording paper reaches the registration roller from the paper feed roller is averaged for each fed recording paper, and the reference stored in advance as normal arrival time. When the average arrival time and the reference arrival time are different, the operation of the paper feeding means is performed so that the arrival time until the recording paper reaches the registration roller from the paper supply roller is the same as the reference arrival time. Since correction is performed for each recording sheet fed, it is possible to reliably prevent a delay in feeding for each recording sheet fed.

  Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram schematically showing an internal configuration of a digital color copier according to an embodiment of the present invention. In this embodiment, a case where the present invention is applied to a copying machine as an example of an image forming apparatus will be described. However, the present invention can also be applied to, for example, a printer apparatus, a facsimile apparatus, a scanner apparatus, and a multifunction apparatus having these functions. It is.

  In FIG. 1, an image forming apparatus 1 constitutes a tandem type digital color copying machine, and an image reading unit 7 for reading a document image and a document image read by the image reading unit 7 are transferred to a recording sheet. A main body 2 for recording, and a recording paper discharge unit 6 for discharging the recording paper onto which the original image is transferred by the main body 2.

  The image reading unit 7 includes a scanner 71 composed of a CCD (Charge Coupled Device) or the like. The image reading unit 7 reads an image of a document placed on the first contact glass 72 by the scanner 71, and sequentially reads a plurality of documents stacked on the document placement unit 73 to the second contact glass 74. The image of the original passing through the second contact glass 74 is read out. Image data read by the scanner 71 is stored in a memory.

  The main body 2 includes a paper feeding unit 10 disposed in the lower part of the housing 3, an image forming unit 30 disposed in the upper part of the housing 3, and a lower part of the image forming unit 30 in the housing 3. The transfer conveyance unit 40 disposed in the housing 3, the fixing unit 50 disposed on the downstream side of the transfer conveyance unit 40 in the housing 3, and the recording paper fed from the paper supply unit 10 are transferred to the transfer conveyance unit 40 side. A first paper transport unit 20 for sending out and a second paper transport unit 21 for discharging the recording paper that has passed through the fixing unit 50 to the recording paper discharge unit 6 are provided. An operation panel 9 for instructing the start of printing, setting a correction mode for correcting a paper feed delay, and setting copying conditions such as a recording paper size is provided at an appropriate position on the main body 2. Yes.

  The sheet feeding unit 10 feeds a bundle of sheets P stacked on the sheet feeding cassette one by one from the uppermost sheet P to the first sheet conveying unit 20 side by the rotation operation of the sheet feeding roller 11. It is configured. The first paper transport unit 20 transports the paper fed from the paper feed unit 10 to a registration roller 24 provided in front of the image forming unit 30 (image forming unit 30B) by various roller pairs 22. The registration roller 24 adjusts the timing between the image forming operation and the paper feeding operation by the image forming units 30B, 30Y, 30M, and 30C.

  A paper feed sensor 81 that detects the leading edge of the recording paper that has passed through the paper feed roller 11 is provided downstream of the paper feed roller 11 in the transport direction. A registration sensor 82 that detects the leading edge of the recording paper that has reached the registration roller 24 is provided upstream of the registration roller 24 in the transport direction. The paper feed sensor 81 and the registration sensor 82 are configured by, for example, a transmissive photosensor, and are disposed at positions where the light emitting element and the light receiving element face each other across the conveyance path of the recording paper. The paper feed sensor 81 and the registration sensor 82 detect that the leading end of the recording paper passes when the light received by the light receiving element is blocked by the recording paper.

  The image forming unit 30 is configured to multiplexly form a plurality of toner images on a recording sheet, and includes a first image forming unit 30Y that forms a yellow toner image and a second image forming that forms a magenta toner image. The unit 30M includes a third image forming unit 30C that forms a cyan toner image and a fourth image forming unit 30B that forms a black toner image. Each of the image forming units 30Y, 30M, 30C, and 30B is arranged at a predetermined interval along the recording paper conveyance direction.

  Each of the image forming units 30Y, 30M, 30C, and 30B includes a photosensitive drum 31, a charging unit 32 disposed to face the circumferential surface of the photosensitive drum 31, and a downstream side of the charging unit 32 and the photosensitive unit. An exposure unit 33 disposed facing the peripheral surface of the drum 31, a developing unit 34 disposed downstream of the exposure unit 33 and opposed to the peripheral surface of the photosensitive drum 31, and the developing unit 34 And a cleaning unit 35 disposed opposite to the circumferential surface of the photosensitive drum 31. Further, a transfer roller 36 described later is disposed on the peripheral surface of the photosensitive drum 31 between the developing unit 34 and the cleaning unit 35, thereby forming the transfer unit 36. The photosensitive drums 31 of the image forming units 30Y, 30M, 30C, and 30B are rotated in the clockwise direction shown in the drawing by a drive motor.

  The transfer conveyance unit 40 includes a driven roller 42 disposed in the vicinity of the first image forming unit 30Y, a driving roller 43 disposed in the vicinity of the fourth image forming unit 30B, and a driven roller 42. The transfer belt 41 that is an endless image carrier disposed across the drive roller 43 and the transfer to a position on the downstream side of the developing unit 34 of the photosensitive drum 31 of each of the image forming units 30Y, 30M, 30C, and 30B. And four transfer rollers 44 disposed so as to be capable of being pressed against each other via a belt 41.

  In the transfer transport unit 40, the recording paper transported from the first paper transport unit 20 is electrostatically attracted onto the transfer belt 41 rotated in the counterclockwise direction shown in the figure by a drive motor and transported downstream. The toner images are transferred to the recording paper at the positions of the transfer portions 36 of the image forming units 30Y, 30M, 30C, and 30B.

  The fixing unit 50 performs a fixing process by heating the recording paper on which the toner images formed on the surface of the photosensitive drum 31 of each of the image forming units 30Y, 30M, 30C, and 30B are transcribed multiple times. And a pressure roller 52 disposed in pressure contact with the heating roller 51. The second paper transport unit 21 discharges the paper on which the image is formed in the image forming units 30Y, 30M, 30C, and 30B and the fixing unit 50 to the recording paper discharge unit 6 by the transport roller pair 23.

  Here, a basic operation of the image forming apparatus 1 configured as described above will be described. First, an original is placed on the first contact glass 72, or an original is placed on the original placement portion 73, the operation panel 9 is operated to set the number of copies, and the start button is operated. Then, the original image is captured by the scanner 71 of the image reading unit 7 and stored in the image memory. The image data stored in the image memory is transmitted to the image forming unit 30.

  In each photosensitive drum 31 of the image forming unit 30, the photosensitive drum 31 rotating in the clockwise direction in FIG. 1 is uniformly charged by the charging unit 32, and the exposure unit 33 (laser) based on the transmitted image data or the like. An electrostatic latent image is formed on the photosensitive drum 31 by a laser beam from an operation unit or the like, and a developer (toner) is attached to the electrostatic latent image by the developing unit 34 to form a toner image.

  On the other hand, the recording paper is fed out from the paper supply unit 10 and conveyed to the image forming unit 30 side by the first paper conveyance unit 20. Then, the timing of the image forming operation of the image forming unit 30 is set by the registration roller 24 and then conveyed to the transfer conveying unit 40. The toner images are sequentially formed on the recording paper by the image forming units 30Y, 30M, 30C, and 30B. Transcribed.

  The recording sheet on which the toner image has been transferred is conveyed to the fixing unit 50, is nipped by the heating roller 51 and the pressure roller 52 while being heated by the heating roller 51, and is conveyed to the downstream side. 21 is discharged to the recording paper discharge unit 6. The toner remaining on the surface of each photosensitive drum 31 having the toner image transferred onto the recording paper is removed by the cleaning unit 35.

  Here, the paper feed delay will be described. For example, when the paper feed roller 11 is worn, the paper feed roller 11 slips when the recording paper is fed from the paper feed cassette until the recording paper passes through the paper feed roller 11 and reaches the registration roller 24. There may be a delay in the time. Such a situation is generally referred to as a paper feed delay, and there is a possibility that the number of printed sheets per unit time may decrease or the leading edge of the image formed on the recording paper may be shifted due to the paper feed delay. . Therefore, in the present invention, such a paper feed delay is prevented.

  FIG. 2 is a block diagram showing a schematic configuration of the image forming apparatus 1 according to the present invention. An image forming apparatus 1 illustrated in FIG. 2 includes a paper feeding unit 10, an image forming unit 30, a paper feeding sensor 81, a registration sensor 82, an operation unit 90, a control unit 100, a ROM (read only memory) 101, and a RAM (random access memory). ) 102 and an EEPROM (Electronically Erasable and Programmable Read Only Memory) 103. In FIG. 2, the same components as those in FIG.

  The paper feed unit 10 includes a paper feed roller motor 130 that feeds recording paper using a paper feed roller 11 and rotationally drives the paper feed roller 11. The paper feed sensor 81 detects the recording paper that has passed through the paper feed roller 11, and outputs a detection signal to the control unit 100 when the recording paper is detected. The registration sensor 82 detects the recording paper that has reached the registration roller 24, and outputs a detection signal to the control unit 100 when the recording paper is detected.

  The ROM 101 is a read-only memory, and stores a control program for controlling the image forming apparatus 1 and the like. The ROM 101 also includes a reference arrival time storage unit 122. The RAM 102 is a volatile memory capable of writing and reading data, is allocated as a work area for the CPU, and stores image data read by the image reading unit 7. The RAM 102 includes an arrival time storage unit 120. The EEPROM 103 is a nonvolatile memory in which data can be written and read and the stored contents are retained even when the power is turned off. The EEPROM 103 also includes an average arrival time storage unit 121.

  The control unit 100 is configured by a CPU (Central Processing Unit) or the like, and the CPU or the like executes a control program stored in the ROM 101, whereby an arrival time measurement unit 111, an arrival time averaging unit 112, and an arrival time comparison are performed. Functions as a unit 113, a correction unit 114, and a correction mode setting unit 115.

  The arrival time measuring unit 111 measures the time from when the recording paper is detected by the paper feed sensor 81 to when the recording paper is detected by the registration sensor 82, so that the recording paper is transferred from the paper supply roller 11 to the registration roller 24. Measure the arrival time to reach.

  The arrival time storage unit 120 stores the arrival time measured by the arrival time measurement unit 111 for a predetermined number of sheets after the start of paper feeding. The arrival time storage unit 120 in the present embodiment stores, for example, arrival times from the first sheet to the fifth sheet. The arrival time storage unit 120 may store arrival times for fewer than five sheets, or may store arrival times for more than five sheets.

  The arrival time averaging unit 112 averages the arrival times measured by the arrival time measuring unit 111 and the arrival times measured in the past. That is, the arrival time averaging unit 112 reads the arrival time for each predetermined number stored in the arrival time storage unit 120 and reads the average arrival time stored in the average arrival time storage unit 121. The arrival time averaging unit 112 averages the arrival times by adding the arrival time read from the arrival time storage unit 120 and the average arrival time read from the average arrival time storage unit 121 and dividing the result by 2. .

  The average arrival time storage unit 121 stores the arrival time averaged by the arrival time averaging unit 112 as the average arrival time for each recording sheet fed. The average arrival time storage unit 121 in the present embodiment stores, for example, the average arrival times from the first sheet to the fifth sheet. The average arrival time storage unit 121 may store an average arrival time of fewer than five sheets, or may store an average arrival time of more than five sheets.

  The reference arrival time storage unit 122 stores in advance the reference arrival time until the recording sheet reaches the registration roller 24 from the sheet feeding roller 11 for each recording sheet to be fed. The reference arrival time storage unit 122 according to the present embodiment stores, for example, reference arrival times from the first sheet to the fifth sheet. The reference arrival time storage unit 122 may store a reference arrival time of fewer than five sheets, or may store a reference arrival time of more than five sheets.

  The operation unit 90 includes, for example, an operation panel 9 and receives a print start instruction from the user. The arrival time comparing unit 113 receives the average arrival time stored in the average arrival time storage unit 121 and the reference arrival time stored in the reference arrival time storage unit 122 when a print start instruction is received by the operation unit 90. Are compared for each recording sheet fed.

  When the average arrival time and the reference arrival time are different from each other as a result of comparing the average arrival time and the reference arrival time by the arrival time comparison unit 113, the correction unit 114 reaches the registration roller 24 from the paper feed roller 11. The operation of the paper supply unit 10 is corrected for each recording paper to be fed so that the arrival time until the reference arrival time is the same as the reference arrival time. Specifically, the correction unit 114 records the recording paper on which the rotation speed of the paper feeding roller 11 is fed so that the time it takes for the recording paper to reach the registration roller 24 from the paper feeding roller 11 is the same as the reference time. Adjust every time. The paper feed roller motor 130 rotationally drives the paper feed roller 11 based on the rotation speed adjusted by the correction unit 114 of the control unit 100.

  The correction mode setting unit 115 corrects the operation of the sheet feeding unit 10 for each recording sheet to be fed so that the arrival time until the recording sheet reaches the registration roller 24 from the sheet feeding roller 11 becomes the reference arrival time. Set the mode. That is, only when the correction mode is set to the correction mode by the correction mode setting unit 115, the correction unit 114 should make the arrival time until the recording paper reaches the registration roller 24 from the paper supply roller 11 the same as the reference arrival time. When the operation of the paper supply unit 10 is corrected for each recording sheet fed, and the correction mode is not set by the correction mode setting unit 115, the above correction is not performed. The operation unit 90 accepts whether or not to set the correction mode, and the correction mode setting unit 115 sets the correction mode when it is accepted that the operation unit 90 sets the correction mode.

  Next, the operation of the image forming apparatus shown in FIG. 2 will be described. FIG. 3 is a flowchart for explaining the operation of the image forming apparatus shown in FIG.

  First, in step S <b> 1, the operation unit 90 performs the operation of the paper feeding unit 10 for each recording paper to be fed so as to set the arrival time until the recording paper reaches the registration roller 24 from the paper feeding roller 11. Whether or not to set a correction mode to be corrected is accepted. Here, when the setting of the correction mode is accepted by the operation unit 90, the correction mode setting unit 115 sets the correction mode. On the other hand, when the setting of the correction mode is not accepted by the operation unit 90, the correction mode setting unit 115 does not set the correction mode. The correction mode setting unit 115 stores, for example, in the RAM 102 whether or not to set the correction mode.

  Next, in step S <b> 2, the operation unit 90 receives a print instruction from the user, and the control unit 100 determines whether a print instruction is received by the operation unit 90. If it is determined that a print instruction has not been received (NO in step S2), the process waits until a print instruction is received, and the determination in step S2 is executed at predetermined intervals.

  On the other hand, when it is determined that the print instruction has been accepted (YES in step S2), in step S3, the control unit 100 refers to the RAM 102 and determines whether the correction mode is set. If it is determined that the correction mode is set (YES in step S3), in step S13, the control unit 100 determines the average arrival time stored in the average arrival time storage unit 121 and the reference arrival time. The reference arrival time stored in the storage unit 122 is compared. If the average arrival time and the reference arrival time are different, the arrival time until the recording paper reaches the registration roller from the paper feed roller is the same as the reference arrival time. Therefore, a correction process for correcting the operation of the paper feeding unit 10 for each recording paper to be fed is executed. The correction process in step S13 will be described later with reference to FIG.

  On the other hand, when it is determined that the correction mode is not set (NO in step S3), the arrival time measurement unit 111 clears the arrival time stored in the arrival time storage unit 120 of the RAM 102 in step S4.

  Next, in step S5, the control unit 100 drives the paper feed roller motor 130 to start paper feed. At this time, the paper feed roller motor 130 feeds paper by rotationally driving the paper feed roller 11 at a preset rotational speed.

  In step S <b> 6, the paper feed sensor 81 detects the recording paper that has passed through the paper feed roller 11 and outputs a detection signal to the control unit 100. In step S <b> 7, the registration sensor 82 detects the recording paper that has reached the registration roller 24, and outputs a detection signal to the control unit 100.

  Next, in step S <b> 8, the arrival time measuring unit 111 measures the arrival time until the recording paper reaches the registration roller 24 from the paper supply roller 11. That is, when the detection signal output from the paper feed sensor 81 is input, the arrival time measurement unit 111 starts timing and measures the arrival time until the detection signal output from the registration sensor 82 is input. .

  Next, in step S9, the arrival time measuring unit 111 determines whether or not the current number of sheets fed is greater than five. The control unit 100 counts the number of sheets fed and stores it in the RAM 102. Here, if it is determined that the current number of sheets fed is 5 or less (NO in step S9), in step S10, the arrival time measuring unit 111 determines the arrival time of the Xth sheet as an arrival time storage unit in the RAM 102. 120.

  In this embodiment, the arrival time storage unit 120 stores the arrival times of the first to fifth recording sheets, and the arrival time measurement unit 111 determines that the current number of fed sheets is 5 or more. However, the present invention is not particularly limited to this, and the arrival time measurement unit 111 determines the number of arrival times stored in the arrival time storage unit 120 (recording sheet). It may be determined whether the number is greater than the number of sheets.

  FIG. 4 is a diagram illustrating an example of the arrival time stored in the arrival time storage unit 120 of the RAM 102. As shown in FIG. 4, the arrival time storage unit 120 stores the arrival times of the first to fifth recording sheets in association with each recording sheet for each job. For example, the arrival time measuring unit 111 stores the arrival time Ta of the first recording sheet in the arrival time storage unit 120, and stores the arrival time Tb of the second recording sheet in the arrival time storage unit 120. The arrival time Tc of the fourth recording sheet is stored in the arrival time storage unit 120, the arrival time Td of the fourth recording sheet is stored in the arrival time storage unit 120, and the arrival time Te of the fifth recording sheet is determined. Store in the arrival time storage unit 120.

  When the number of fed sheets exceeds 5, only the arrival times Ta to Te for the first to fifth sheets are stored, and the arrival times for the sixth and subsequent sheets are not stored. When the number of fed sheets is less than 5, for example, when the number of fed sheets is 3, only the arrival times Ta, Tb, and Tc from the first sheet to the third sheet are stored. The arrival times of the fourth and fifth sheets are not stored, and the area for storing the arrival times of the fourth and fifth sheets is empty.

  Returning to FIG. 3, if it is determined that the current number of sheets fed is greater than 5 (YES in step S <b> 9), or the arrival time measuring unit 111 reaches the arrival time storage unit 120 of the RAM 102. In step S11, the control unit 100 determines whether the job is completed, that is, whether all the number of recording sheets instructed for printing have been fed. If it is determined that the job has not ended (NO in step S11), the process returns to step S5, and the control unit 100 drives the paper feed roller motor 130 to feed the next recording paper. Start.

  On the other hand, when it is determined that the job has been completed (YES in step S11), in step S12, the arrival time averaging unit 112 determines the arrival time measured by the arrival time measuring unit 111 and the arrival times measured in the past. Averaging processing is performed to average and. The averaging process in step S12 will be described later with reference to FIG.

  FIG. 5 is a flowchart for explaining the averaging process in step S12 of FIG. The averaging process shown in FIG. 5 is executed every time the job is completed.

  First, in step S <b> 21, the arrival time averaging unit 112 sets the number of fed sheets X to 1. Next, in step S22, the arrival time averaging unit 112 determines whether or not the Xth arrival time stored in the arrival time storage unit 120 of the RAM 102 is empty, that is, the Xth arrival time. It is determined whether or not it is stored.

  When it is determined that the Xth arrival time is not empty (NO in step S22), in step S23, the arrival time averaging unit 112 calculates the Xth average arrival time. Specifically, the arrival time averaging unit 112 reads the Xth arrival time stored in the arrival time storage unit 120 of the RAM 102 and stores the past X stored in the average arrival time storage unit 121 of the EEPROM 103. Read the average arrival time of the first sheet. Then, the arrival time averaging unit 112 obtains the Xth arrival time read from the arrival time storage unit 120 of the RAM 102 and the past Xth average arrival time read from the average arrival time storage unit 121 of the EEPROM 103. The average arrival time of the Xth sheet is calculated by adding and dividing the added value by 2.

  Next, in step S <b> 24, the arrival time averaging unit 112 stores the Xth average arrival time in the average arrival time storage unit 121 of the EEPROM 103. FIG. 6 is a diagram illustrating an example of the average arrival time stored in the average arrival time storage unit 121 of the EEPROM 103. As shown in FIG. 6, the average arrival time storage unit 121 stores the average arrival time of the first to fifth recording sheets in association with each recording sheet for one job.

  For example, the arrival time averaging unit 112 stores the average arrival time TA of the first recording sheet in the average arrival time storage unit 121 and the average arrival time TB of the second recording sheet as the average arrival time storage unit 121. And the average arrival time TC of the third recording sheet is stored in the average arrival time storage unit 121, and the average arrival time TD of the fourth recording sheet is stored in the average arrival time storage unit 121, and the fifth sheet The average arrival time TE of the eye recording paper is stored in the average arrival time storage unit 121.

  In the initial state, the average arrival time storage unit 121 of the EEPROM 103 stores in advance the reference arrival time stored in the reference arrival time storage unit 122 of the ROM 101 as the average arrival time.

  Returning to FIG. 5, if it is determined that the arrival time of the Xth sheet is empty (YES in step S22), or if the average arrival time of the Xth sheet is calculated, the arrival time average is calculated in step S25. The conversion unit 112 increments the number of fed sheets X by 1.

  Next, in step S <b> 26, the arrival time averaging unit 112 determines whether or not the sheet feed number X is greater than 5. Here, when it is determined that the number of fed sheets X is larger than 5 (YES in step S26), the arrival time averaging unit 112 ends the averaging process.

  In the present embodiment, the arrival time storage unit 120 and the average arrival time storage unit 121 store the arrival times and average arrival times of the first to fifth recording sheets, and the arrival time averaging unit 112 determines whether or not the current paper feed number X is greater than 5, but the present invention is not particularly limited to this, and the arrival time averaging unit 112 determines that the current paper feed number X is It may be determined whether or not the arrival time and the average arrival time stored in the arrival time storage unit 120 and the average arrival time storage unit 121 are greater than the number (number of recording sheets).

  On the other hand, if it is determined that the number X of sheets fed is 5 or less (NO in step S26), the process returns to step S22, and the arrival time averaging unit 112 is stored in the arrival time storage unit 120 of the RAM 102. It is determined whether the arrival time of the Xth sheet is empty.

  For example, when the number of fed sheets is 3, the arrival time storage unit 120 of the RAM 102 stores arrival times for the first to third sheets. Therefore, the arrival time averaging unit 112 calculates an average arrival time for the first to third sheets and stores it in the average arrival time storage unit 121. When the number of fed sheets is 5 or more, the arrival time storage unit 120 of the RAM 102 stores the arrival times for the first to fifth sheets. Therefore, the arrival time averaging unit 112 calculates the average arrival time for the first to fifth sheets and stores it in the average arrival time storage unit 121.

  FIG. 7 is a flowchart for explaining the correction processing in step S13 of FIG.

  First, in step S <b> 41, the arrival time comparison unit 113 sets the number of fed sheets X to 1. Next, in step S <b> 42, the arrival time comparison unit 113 reads the X-th average arrival time stored in the average arrival time storage unit 121 of the EEPROM 103 and stores it in the reference arrival time storage unit 122 of the ROM 101. Read the reference arrival time of the Xth sheet. Then, the arrival time comparison unit 113 has the same average arrival time of the Xth sheet read from the average arrival time storage unit 121 of the EEPROM 103 as the Xth reference arrival time of the Xth sheet read from the reference arrival time storage unit 122 of the ROM 101. It is determined whether or not.

  FIG. 8 is a diagram illustrating an example of the reference arrival time stored in the reference arrival time storage unit 122 of the ROM 101. As shown in FIG. 8, the reference arrival time storage unit 122 stores the reference arrival times of the first to fifth recording sheets in association with each recording sheet.

  For example, the reference arrival time Tra of the first recording sheet is stored in advance in the reference arrival time storage unit 122, and the reference arrival time Trb of the second recording sheet is stored in advance in the reference arrival time storage unit 122. The reference arrival time Trc of the third recording sheet is stored in the reference arrival time storage unit 122 in advance, and the reference arrival time Trd of the fourth recording sheet is stored in the reference arrival time storage unit 122 in advance. The reference arrival time Tre of the fifth recording sheet is stored in the reference arrival time storage unit 122 in advance. The reference arrival times Tra to Tre for the first to fifth sheets are set to the optimum time for feeding the recording paper by conducting an experiment in advance.

  In addition, the reference arrival time storage unit 122 in the present embodiment stores the reference arrival times Tra to Tre up to the first to fifth sheets in advance, but the present invention is not particularly limited to this, and 1 to 5 sheets. When the reference arrival time up to the eyes may be the same time, the reference arrival time storage unit 122 stores only one reference arrival time, and the arrival time comparison unit 113 reads out from the average arrival time storage unit 121 of the EEPROM 103. It is determined whether the average arrival time of the Xth sheet is the same as the reference arrival time read from the reference arrival time storage unit 122 of the ROM 101.

  Furthermore, the arrival time comparison unit 113 in the present embodiment determines whether or not the average arrival times TA to TE for the first to fifth sheets and the reference arrival times Tra to Tre for the first to fifth sheets are the same. Although it is determined, the present invention is not particularly limited to this, and it is determined whether or not the average arrival times TA to TE for the first to fifth sheets are longer than the reference arrival times Tra to Tre for the first to fifth sheets. You may judge.

  Furthermore, the reference arrival time storage unit 122 does not store the reference arrival times Tra to Tre for the first to fifth sheets, but sets the reference arrival time range in which the recording paper can be normally printed to the first to fifth sheets. The arrival time comparison unit 113 determines whether or not the average arrival times TA to TE for the first to fifth sheets are within the reference arrival time range for the first to fifth sheets. May be.

  Returning to FIG. 7, when it is determined that the average arrival time of the Xth sheet and the reference arrival time of the Xth sheet are not the same (NO in step S42), in step S43, the correction unit 114 causes the correction unit 114 to The paper feed speed is corrected so that the arrival time until the recording paper reaches the registration roller 24 from the paper feed roller 11 is the same as the reference arrival time of the Xth sheet. Specifically, the correction unit 114 rotates the paper feed roller 11 so that the arrival time until the Xth recording sheet reaches the registration roller 24 from the paper feed roller 11 is the same as the Xth reference arrival time. Adjust the speed. For example, the correction unit 114 calculates the corrected rotation speed of the sheet feed roller motor 130 based on the following equation (1), and instructs the sheet feed roller motor 130 to rotate at the calculated rotation speed.

v = V × TX / Trx (1)
In the above equation (1), v represents the corrected rotational speed of the paper feed roller motor 130, V represents the current rotational speed of the paper feed roller motor 130, and TX represents the average arrival time of the Xth sheet. Trx represents the X-th reference arrival time. The above correction method is an example, and other correction methods may be used.

  Next, in step S44, the control unit 100 drives the paper feed roller motor 130 to start paper feeding. At this time, the paper feed roller motor 130 rotates the paper feed roller 11 at the rotational speed corrected by the correction unit 114 to feed paper.

  When it is determined that the average arrival time of the Xth sheet and the reference arrival time of the Xth sheet are the same (YES in step S42), in step S45, the arrival time comparing unit 113 sets the number of fed sheets X by one. Increment.

  Next, in step S <b> 46, the arrival time comparison unit 113 determines whether or not the sheet feed number X is greater than 5. Here, if it is determined that the number of fed sheets X is 5 or less (NO in step S46), in step S47, the arrival time comparing unit 113 determines whether the job is completed, that is, all of the print instructions. It is determined whether or not the number of recording sheets has been fed. If it is determined that the job has ended (YES in step S47), the correction process ends.

  In the present embodiment, the average arrival time storage unit 121 and the reference arrival time storage unit 122 store the average arrival times and reference arrival times of the first to fifth recording sheets, and compare the arrival times. The unit 113 compares the average arrival time and the reference arrival time for each recording sheet from the first sheet to the fifth sheet. However, the present invention is not particularly limited to this, and the arrival time comparison unit 113 calculates the average arrival time. The average arrival time and the reference arrival time are compared for each number of recording sheets corresponding to the average arrival time and the number of reference arrival times (number of recording sheets) stored in the arrival time storage unit 121 and the reference arrival time storage unit 122. May be.

  On the other hand, if it is determined that the job has not ended (NO in step S47), the process returns to step S42, and the arrival time comparison unit 113 reads the average of the X sheets read from the average arrival time storage unit 121 of the EEPROM 103. It is determined whether or not the arrival time is the same as the Xth reference arrival time read from the reference arrival time storage unit 122 of the ROM 101.

  If it is determined that the number of fed sheets X is greater than 5 (YES in step S46), in step S48, the correction unit 114 determines whether the sheet feeding speed is corrected for the fifth sheet. If it is determined that the paper feed speed has been corrected for the fifth sheet (YES in step S48), in step S49, the correction unit 114 moves the Xth recording sheet from the paper feed roller 11 to the registration roller 24. The paper feed speed is corrected so that the arrival time until the arrival is the same as the reference arrival time for the fifth sheet. Specifically, the correction unit 114 rotates the paper feed roller 11 so that the arrival time until the Xth recording sheet reaches the registration roller 24 from the paper feed roller 11 is the same as the reference arrival time of the fifth sheet. Adjust the speed.

  For example, the correction unit 114 stores in the RAM 102 the rotational speed of the paper feed roller motor 130 corrected when the fifth recording paper is fed, and feeds the paper so as to rotate at the rotational speed stored in the RAM 102. Instructs the roller motor 130.

  On the other hand, if it is determined that the sheet feeding speed is not corrected for the fifth sheet (NO in step S48), or if the X sheet feeding speed is corrected in step S49, the control unit in step S50 Reference numeral 100 drives the paper feed roller motor 130 to start paper feeding. At this time, if the X-th sheet feeding speed is corrected in step S49, the sheet feeding roller motor 130 rotates and feeds the sheet feeding roller 11 at the rotation speed corrected by the correction unit 114 to feed the sheet. If it is determined that the sheet feeding speed is not corrected for the fifth sheet and the rotation speed is not corrected by the correction unit 114, the sheet feeding roller motor 130 feeds at a preset normal rotation speed. The roller 11 is rotated to feed paper.

  As described above, in this embodiment, the average arrival time of a predetermined number of sheets from the start of sheet feeding is stored, but when feeding more than this predetermined number of sheets, the predetermined number of sheets (in this embodiment, It is determined whether or not the correction has been made with the fifth sheet). When the correction is made with the predetermined number of sheets, the same correction as that performed with the predetermined number of sheets is performed when the predetermined number of sheets are fed. In addition, when the correction is not made at the predetermined number of sheets, the correction is not performed when the paper is fed more than the predetermined number.

  Next, in step S51, the arrival time comparison unit 113 determines whether or not the job has been completed, that is, whether or not all the number of recording sheets instructed for printing have been fed. If it is determined that the job has ended (YES in step S51), the correction process ends.

  On the other hand, if it is determined that the job has not ended (NO in step S51), the process returns to step S45, and the arrival time comparison unit 113 increments the number of fed sheets X by one.

  In this way, the recording paper is fed by the paper feed unit 10 using the paper feed roller 11. Then, the arrival time until the recording paper reaches the registration roller 24 from the paper supply roller 11 is measured, and the measured arrival time and the arrival time measured in the past are averaged for each recording paper fed. Then, the averaged arrival time is stored for each recording sheet fed as the average arrival time. The reference arrival time until the recording paper reaches the registration roller 24 from the paper supply roller 11 is stored in advance. In addition, the average arrival time and the reference arrival time are compared for each recording sheet to be fed, and when the average arrival time and the reference arrival time are different, the recording paper reaches the registration roller 24 from the sheet feeding roller 11. The operation of the sheet feeding unit 10 is corrected for each recording sheet to be fed so that the arrival time is the same as the reference arrival time.

  Therefore, the average arrival time obtained by averaging the arrival time until the recording paper reaches the registration roller 24 from the paper supply roller 11 for each fed recording paper, and the reference arrival time stored in advance as normal arrival time When the average arrival time and the reference arrival time are different, the operation of the paper feeding unit 10 is performed so that the arrival time until the recording paper reaches the registration roller 24 from the paper feed roller 11 is the same as the reference arrival time. Is corrected for each recording sheet to be fed, so that a delay in feeding can be reliably prevented for each recording sheet to be fed.

  Even if the arrival time of each recording paper varies for each job, the measured arrival time and the arrival time measured in the past are averaged for each fed recording paper. The reliability of the average arrival time data compared with the arrival time can be improved.

  In addition, the average arrival time and the reference arrival time are compared for each recording sheet to be fed, and when the average arrival time and the reference arrival time are different, the recording paper reaches the registration roller 24 from the sheet feeding roller 11. In order to make the arrival time the same as the reference arrival time, the rotational speed of the paper feed roller 11 is adjusted for each recording paper to be fed. Accordingly, when the arrival time until the recording paper reaches the registration roller 24 from the paper feed roller 11 is slower than the reference arrival time, the rotational speed of the paper feed roller 11 is set to be faster than the preset rotational speed. By adjusting, it is possible to prevent a paper feed delay for each recording paper fed.

  Further, only when the correction mode for correcting the operation of the paper feed unit 10 is set so that the arrival time until the recording paper reaches the registration roller 24 from the paper feed roller 11 is set as the reference arrival time, The reference arrival time is compared for each recording sheet to be fed, and when the average arrival time and the reference arrival time are different, the arrival time until the recording sheet reaches the registration roller 24 from the sheet feeding roller 11 is determined as the reference arrival time. The operation of the sheet feeding unit 10 is corrected for each recording sheet to be fed.

  Therefore, only when the correction mode is set, the operation of the paper feed unit 10 is fed so that the arrival time until the recording paper reaches the registration roller 24 from the paper feed roller 11 is the same as the reference arrival time. Since correction is performed for each recording sheet, normal feeding can be performed without setting the correction mode until a paper feed delay occurs. When a paper feed delay occurs, the paper is fed in the correction mode. It is possible to prevent a delay in feeding each recording sheet.

  Furthermore, the measured arrival time is temporarily stored for each fed recording sheet, and after the job is finished, the temporarily stored arrival time and the average of the stored average arrival times Since the value is calculated for each recording sheet fed, the processing can be simplified rather than averaging every time the arrival time is measured, and the averaging processing speed can be improved.

  In this embodiment, the correction unit 114 adjusts the rotation speed of the paper feed roller 11 so that the arrival time until the recording paper reaches the registration roller 24 from the paper feed roller 11 is the same as the reference arrival time. However, the present invention is not particularly limited to this, and in order to make the arrival time until the recording paper reaches the registration roller 24 from the paper supply roller 11 to be the same as the reference arrival time, the paper supply roller 11 does not record the recording paper. The paper feed timing for paper feed may be adjusted. That is, the correction unit 114 advances the paper feed timing of the paper feed roller 11 by the time of the paper feed delay, so that the arrival time until the recording paper reaches the registration roller 24 from the paper feed roller 11 is the reference arrival time. To be the same.

  In this case, the average arrival time and the reference arrival time are compared for each recording sheet to be fed. If the average arrival time and the reference arrival time are different, the recording sheet reaches the registration roller 24 from the sheet feeding roller 11. In order to make the arrival time equal to the reference arrival time, the paper feed timing at which the paper feed roller 11 feeds the recording paper is adjusted for each recording paper to be fed. Therefore, when the arrival time until the recording paper reaches the registration roller 24 from the paper feed roller 11 is later than the reference arrival time, the paper feed of the paper feed roller 11 is made faster than the preset paper feed timing. By adjusting the timing for each recording sheet fed, it is possible to prevent a delay in feeding for each recording sheet fed.

1 is a diagram schematically showing an internal configuration of a digital color copier according to an embodiment of the present invention. FIG. 1 is a block diagram showing a schematic configuration of an image forming apparatus according to the present invention. 3 is a flowchart for explaining the operation of the image forming apparatus shown in FIG. It is a figure which shows an example of the arrival time memorize | stored in the arrival time memory | storage part of RAM. It is a flowchart for demonstrating the averaging process in step S12 of FIG. It is a figure which shows an example of the average arrival time memorize | stored in the average arrival time memory | storage part of EEPROM. It is a flowchart for demonstrating the correction | amendment process in step S13 of FIG. It is a figure which shows an example of the reference arrival time memorize | stored in the reference arrival time memory | storage part of ROM.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Paper feed part 30 Image formation part 81 Paper feed sensor 82 Registration sensor 90 Operation part 100 Control part 101 ROM
102 RAM
103 EEPROM
111 Arrival Time Measuring Unit 112 Arrival Time Averaging Unit 113 Arrival Time Comparison Unit 114 Correction Unit 115 Correction Mode Setting Unit 120 Arrival Time Storage Unit 121 Average Arrival Time Storage Unit 122 Reference Arrival Time Storage Unit 130 Paper Feed Roller Motor

Claims (5)

A paper feed means for feeding recording paper using a paper feed roller;
Arrival time measuring means for measuring the arrival time until the recording paper reaches the registration roller from the paper feed roller;
Arrival time averaging means for averaging the arrival times measured by the arrival time measuring means and the arrival times measured in the past for each recording sheet fed;
Average arrival time storage means for storing each of the fed recording sheets as the arrival time averaged by the arrival time averaging means;
Reference arrival time storage means for storing in advance a reference arrival time until the recording paper reaches the registration roller from the paper feed roller;
The average arrival time stored in the average arrival time storage means and the reference arrival time stored in the reference arrival time storage means are compared for each paper sheet to be fed, and the average arrival time and the reference When the arrival time is different, the operation of the sheet feeding unit is corrected for each recording sheet to be fed so that the arrival time until the recording sheet reaches the registration roller from the sheet feeding roller is the same as the reference arrival time. An image forming apparatus comprising: a correction unit.   2. The image forming apparatus according to claim 1, wherein the operation of the sheet feeding unit corrected by the correcting unit is to adjust the rotation speed of the sheet feeding roller for each recording sheet fed.   2. The operation of the paper feeding unit corrected by the correcting unit is to adjust a paper feeding timing at which a paper feeding roller feeds recording paper for each recording paper fed. The image forming apparatus described. A correction mode setting means for setting a correction mode for correcting the operation of the paper feeding means so that the arrival time until the recording paper reaches the registration roller from the paper feeding roller becomes the reference arrival time;
The correction means has an average arrival time stored in the average arrival time storage means and a reference arrival time stored in the reference time storage means only when the correction mode is set by the correction mode setting means. When the average arrival time and the reference arrival time are different, the arrival time until the recording paper reaches the registration roller from the paper supply roller is the same as the reference arrival time. The image forming apparatus according to claim 1, wherein the operation of the paper feeding unit is corrected for each recording paper fed. An arrival time storage means for temporarily storing the arrival time measured by the arrival time measurement means for each recording paper fed;
The arrival time averaging means feeds an average value of the arrival time stored in the arrival time storage means and the average arrival time stored in the average arrival time storage means after the job is completed. The image forming apparatus according to claim 1, wherein the calculation is performed for each recording sheet.

Images