JP2006240025A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adjust an image forming position of an image forming apparatus with good accuracy even after a continuous paper is returned back. <P>SOLUTION: In accordance with a difference between an expected value indicating a predetermined amount of carrying so that after carrying the continuous paper 12 is stopped, the continuous paper 12 is returned back to the next image forming starting position, and an amount of movement of the continuous paper 12 in the anti-carrying direction measured by a part 42 for measuring the amount of movement of the continuous paper for measuring the amount of movement in the anti-carrying direction of the continuous paper 12 when the continuous paper 12 is carried in the anti-carrying direction, as it is possible to correct an exposing light timing adjusting value for adjusting the image forming starting position calculated based on the detected result of a resist mark 40, even after the continuous paper 12 is returned back, the image forming position of the image forming apparatus 10 can be accurately adjusted. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus that forms an image on continuous paper.

  Conventionally, an image forming apparatus that forms an image on continuous paper is known. In such an image forming apparatus, in order to adjust the image forming position of an image to be formed on continuous paper, a technique for detecting a mark previously formed on continuous paper and adjusting the image forming position according to the mark detection result It has been known.

  In such an image forming apparatus, when the continuous paper transport is stopped, the continuous paper transport mechanism does not stop at the same time when the transport stop signal is input, but generally decelerates after continuing a predetermined amount of transport operation. When the conveyance is stopped and the image formation is started after the conveyance is stopped, there is a problem that an excessive blank area is generated on the continuous sheet.

  In order to suppress the occurrence of such an excessive white paper region, a technique is known in which when continuous paper conveyance is stopped, the continuous paper is returned to the next image formation start position and then conveyed again (for example, Patent Document 1).

According to the technique disclosed in Patent Document 1, a continuous paper that is transported in the transport direction after a transport stop signal is output to the transport mechanism and the continuous paper transport stop operation is started until the continuous paper transport is stopped. Is calculated based on the conveyance speed of the continuous paper, and the continuous paper is returned in the non-conveyance direction by controlling the operation of the conveyance mechanism in accordance with the calculated amount of continuous paper.
JP 2003-291437 A

  If the continuous paper can be returned to the next image formation start position with high accuracy when the continuous paper is returned in the above prior art, the image forming position can be accurately determined based on the detection result of the mark detected before returning the continuous paper. Although it can be adjusted well, the detection result of the mark detected before returning the continuous paper when the transport amount of the intended continuous paper in the reverse transport direction is different from the actual amount of continuous paper returned When the image forming position is adjusted based on the above, there is a problem that the adjustment accuracy of the image forming position is lowered. In particular, in continuous paper having no holes for conveyance (so-called pinless continuous paper), the amount of the continuous paper to be conveyed in the reverse conveyance direction and the amount of continuous paper actually returned are often different. Deterioration of the image forming position adjustment system may be a problem.

  The present invention has been made to solve the above-described problems, and provides an image forming apparatus capable of accurately adjusting the image forming position of the image forming apparatus even after the continuous paper is returned. Objective.

  In order to achieve the above object, an image forming apparatus according to the present invention includes a conveying unit that conveys a continuous sheet on which a reference mark is formed in advance in the conveying direction, and an image on the continuous sheet based on an input of an image formation start instruction signal. An image forming unit that starts forming, a detecting unit that detects the reference mark formed on the continuous paper, and a position for starting image formation on the continuous paper based on a detection result by the detecting unit A calculation means for calculating the adjustment value, an output means for outputting the image formation start instruction signal to the image formation means based on the calculated adjustment value, and a stop for stopping conveyance of the continuous paper in the conveyance direction. When a signal is input, a predetermined transport amount is set so that the continuous paper is transported to a predetermined position and stopped, and then the continuous paper is returned to the next image formation start position. Measures the amount of movement of the continuous paper in the non-conveyance direction from the time when the conveyance is stopped until the next image formation start position is returned to the next image formation start position. And a correction unit that corrects the adjustment value according to a difference between the movement amount measured by the measurement unit and the transport amount.

  The calculation means of the image forming apparatus of the present invention calculates an adjustment value for adjusting the image formation start position on the continuous paper by the image forming means based on the detection result of the reference mark detected by the detection means. The image forming unit starts image formation on continuous paper when an image formation start signal is input from the output unit based on the adjustment value calculated by the calculation unit. When a stop signal for stopping the conveyance of the continuous paper in the conveyance direction is input to the conveyance control unit, the conveyance control unit conveys the continuous paper to a predetermined position and stops the conveyance, and then is determined in advance. The transporting means is controlled so as to return the transported continuous paper. When the measurement unit measures the amount of movement of the continuous sheet in the reverse conveyance direction after stopping the conveyance of the continuous sheet until it is returned to the image forming position of the next image, the correction unit is measured by the measurement unit. The adjustment value calculated by the calculation unit is corrected according to the difference between the movement amount and a conveyance amount that is set in advance so that the continuous sheet is returned to the next image formation start position.

  As described above, after the conveyance of the continuous paper is stopped, the conveyance amount determined in advance so that the continuous paper is returned to the formation start position of the next image, and the conveyance measured by the measuring unit is stopped, and then the next image is obtained. An adjustment value for adjusting the image formation start position calculated based on the detection result of the reference mark according to the difference from the amount of movement of the continuous paper in the reverse conveyance direction until it is returned to the image formation start position. Since correction can be performed, the image forming position of the image forming apparatus can be adjusted with high accuracy even after the continuous paper is returned.

  The conveyance control unit conveys the continuous paper to a position where the image is fixed by a fixing unit that fixes the image formed by the image forming unit to the continuous paper, and then stops the conveyance. A stop signal for stopping the conveyance in the conveyance direction of the continuous paper is input by controlling the conveyance unit so that the conveyance amount is returned so that the continuous paper is returned to the image formation start position. Since the continuous sheet can be returned after the unfixed image is fixed on the continuous sheet sometimes, it is possible to suppress the occurrence of an unfixed image due to the stop of the transport in the transport direction.

  In addition, by using a pinless continuous paper having no conveyance holes as the continuous paper, it is possible to effectively suppress the difference between the movement amount measured by the measuring means and a predetermined conveyance amount. .

  The correction unit corrects the difference obtained by subtracting the movement amount measured by the measurement unit from the transport amount by adding the adjustment value to the adjustment value. Therefore, the adjustment value of the image formation start position on the continuous paper is measured. Correction can be made so as to suppress a difference between the movement amount measured by the means and a predetermined conveyance amount.

  As described above, according to the image forming apparatus of the present invention, the conveyance amount determined in advance so that the continuous paper is returned to the formation start position of the next image after stopping the conveyance of the continuous paper, and the measurement unit. An adjustment value for adjusting the image formation start position according to the difference from the amount of movement in the reverse conveyance direction of the continuous paper from when the measured conveyance is stopped until it is returned to the next image formation start position. Since the image forming position of the image forming apparatus can be adjusted with high accuracy even after the continuous paper is returned, an effect can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the image forming apparatus 10 includes an image forming unit 30 for forming an image based on image data and a main controller 32 for controlling the main body of the image forming apparatus 10.

  The image forming unit 30 includes a back tension roller 26, a transfer device 21, a fixing device 22, a drive roller 24, a developing device 19, a cleaning device 34, a static elimination LED device 36, a photoconductor 20, a charging device 38, and an LED unit 18. ing.

  When the continuous paper 12 is supplied from an external device (not shown) to the image forming apparatus 10, the supplied continuous paper 12 is transported in the transport direction B and after passing through the transfer device 21 and the fixing device 22, the drive roller 24. Is supplied to the outside, not shown.

  The photoreceptor 20 rotated in the A direction is uniformly charged by the charging device 38 and then scanned and exposed by the LED unit 18. As a result, an electrostatic latent image corresponding to the image is formed on the photoreceptor 20. The electrostatic latent image formed on the photoconductor 20 is developed by the developing device 19, and then the toner image on the photoconductor 20 is transferred to the continuous paper 12. The back tension roller 26 is provided with a continuous paper movement amount measuring unit 42 for measuring the movement amount of the continuous paper 12 in the reverse conveyance direction when the continuous paper 12 is conveyed in the reverse conveyance direction.

  When the continuous paper 12 conveyed in the conveyance direction B by the back tension roller 26 and the drive roller 24 is conveyed to the installation position of the photoconductor 20, the toner image on the surface of the photoconductor 20 is transferred to the continuous paper 12 by the transfer device 21. After that, it is conveyed to the fixing device 22. The fixing device 22 fixes the toner image transferred on the continuous paper 12 to the continuous paper 12. The continuous paper 12 on which the toner image is fixed is discharged out of the image forming apparatus 10. The toner on the photosensitive member 20 remaining without being transferred to the continuous paper 12 by the transfer device 21 is removed by the cleaning device 34. The photosensitive member 20 from which the remaining toner has been removed is uniformly charged by the charging device 38 again after being discharged by the discharging LED device 36.

  In the present embodiment, the fixing device 22 will be described using a flash fixing method in which a xenon lamp emits light and the toner is melted by the heat to fix the toner image on the continuous paper 12. It is not limited to a particular form.

  As shown in FIG. 2, registration marks 40 are formed in advance on the continuous paper 12 at predetermined intervals in the conveyance direction of the continuous paper 12 in order to suppress a shift in the formation start position of each image. These registration marks 40 are detected by a mark detection sensor 16 provided on the upstream side of the photosensitive member 20 in the conveyance direction (arrow B direction) of the continuous paper 12.

  In the present embodiment, a case will be described in which the registration mark 40 is formed at one end in a direction orthogonal to the conveyance direction of the continuous paper 12 at a predetermined interval in the conveyance direction. You may make it form in the both ends of the orthogonal direction.

  Although a detailed mechanism diagram is omitted, the mark detection sensor 16 is a line sensor including an illumination lamp, a condenser lens, a reflection mirror, and a CCD. The configuration of the mark detection sensor 16 is not limited to such a configuration. The mark detection sensor 16 is provided at a position where the registration mark 40 formed on the continuous paper 12 can be detected, and outputs an output signal based on the detected registration mark 40 to the main controller 32.

  As shown in FIG. 3, the main controller 32 of the image forming apparatus 10 includes a mark detection sensor 16, a continuous paper movement amount measurement unit 42, an input unit 46 for inputting various data, a continuous paper conveyance unit 54, and image formation. The unit 56 is connected to be able to exchange data and commands.

  The continuous paper conveyance unit 54 includes a drive unit for driving each of various conveyance units related to conveyance of the continuous paper 12 such as the back tension roller 26 and the drive roller 24 shown in FIG. The continuous paper is transported along the path in the transport direction (arrow B direction, see FIGS. 1 and 2) or in the opposite transport direction. The image forming unit 56 includes the developing device 19, the cleaning device 34, the static elimination LED device 36, the photoconductor 20, the charging device 38, and the LED unit 18.

  The main controller 32 includes a control unit 48, a timer 50, and a memory 52. The control unit 48 that controls the entire image forming apparatus 10 is connected to the timer 50 and the memory 52 through a bus such as a data bus or an address bus (not shown) so as to exchange data and commands with each other. The memory 52 has an expected value indicating a predetermined conveyance amount when the continuous paper 12 is conveyed in the opposite conveyance direction and returned to the next image formation start position, the conveyance speed of the continuous paper 12, and the formation interval of the registration marks 40. A time indicating a detection interval when the registration mark 40 is detected in an ideal state with no positional deviation calculated in advance based on the above (hereinafter referred to as an ideal detection interval), and an exposure calculated in advance based on the ideal detection interval. The reference exposure start timing indicating the time from the detection of the registration mark of the page on which printing starts to the start of exposure and the continuous paper conveyance start instruction timing value indicating the timing for starting the conveyance of the continuous paper 12 are stored in advance. The exposure start timing adjustment value for adjusting the image forming position based on the output signal output from the mark detection sensor 16 is stored. The timer 50 is configured to include a plurality of timers so that they can operate separately.

  Next, processing executed by the control unit 48 will be described.

  When a print job is input from the external device (not shown) to the image forming apparatus 10 via the input unit 46, the control unit 48 executes the processes shown in FIG. 4 and FIG. The process proceeds to (formation control) and step 200 (continuous paper conveyance control).

  In step 100, the exposure start timing adjustment value when the registration mark of the page where exposure is to be started is detected is read from the memory 52. If the exposure start timing adjustment value cannot be managed when the registration mark of the page to start exposure is detected in the memory 52 due to paper change / jamming, the exposure start timing adjustment value is “0”. Process as.

  In the next step 102, the exposure start timing is calculated by adding the exposure start timing adjustment value to the reference exposure start timing stored in the memory 52.

  In the next step 104, counting by the timer 50 is started.

  In the next step 106, negative determination is repeated until the count time by the timer 50 reaches the exposure start timing calculated in step 102. If the determination is affirmative, the process proceeds to step 108.

  In the next step 108, the count of the timer 50 that has started counting in step 104 is stopped and the count value is reset.

  In the next step 110, an exposure start signal as an image formation start instruction signal for instructing the start of exposure according to the image data is output to the image forming unit 56. When an exposure start signal is input to the image forming unit 56, the LED unit 18 starts exposure according to the image data in accordance with the timing at which the exposure start signal is input. By the processing of step 110, exposure to the photoconductor 20 is started at the exposure timing adjusted by the exposure start timing adjustment value.

  In the next step 112, it is determined whether or not the image formation of all the page image data included in the input print job has been completed. If the determination is negative, the process returns to step 100. If the determination is affirmative, the routine ends. To do.

  In step 200, the continuous paper conveyance start instruction timing value is read from the memory 52.

  In the next step 202, counting by the timer 50 is started.

  In the next step 204, the negative determination is repeated until the count time by the timer 50 reaches the continuous paper conveyance start instruction timing read in step 200. If the determination is affirmative, the process proceeds to step 206.

  In the next step 206, a conveyance start instruction signal for starting the conveyance of the continuous paper 12 is output to the continuous paper conveyance unit 54, and the count of the timer 50 started in the above step 202 is stopped and reset. When the transport start instruction signal is input, the continuous paper transport unit 54 starts transporting the continuous paper 12 in the transport direction B by driving the drive roller 24 and the back tension roller 26. When the continuous paper 12 is transported in the transport direction B, the back tension roller 26 rotates at a slower speed than the drive roller 24. By controlling the rotational speeds of the back tension roller 26 and the drive roller 24 in this way, it is possible to suppress the occurrence of slack in the continuous paper 12 between the back tension roller 26 and the drive roller 24. It has become.

  In the next step 208, the registration mark detection timing monitoring is started by starting the count by the timer 50.

  In the next step 210, a negative determination is repeated until an output signal indicating that a mark formed on the continuous paper 12 has been detected is input from the mark detection sensor 16, and the process proceeds to step 212 if the determination is affirmative.

  In the next step 212, an adjustment value of the exposure start timing by the LED unit 18 is calculated from the ideal detection timing based on the ideal detection interval stored in the memory 52 and the detection timing of the registration mark 40 detected in step 210. To do. In the present embodiment, the adjustment value of the exposure start timing is from the ideal detection timing until the registration mark 40 is detected by the mark detection sensor 16 or from the detection of the registration mark 40 by the mark detection sensor 16 to the ideal detection timing. It is indicated by the difference obtained by subtracting the time.

  In the next step 214, the exposure start timing adjustment value calculated in step 212 is stored in the memory 52.

  In the next step 216, it is determined whether or not a stop signal for stopping the conveyance of the continuous paper 12 is input from the input unit 46. If the determination is negative, the process returns to step 210, and if the determination is positive, the process proceeds to step 218. .

  In step 218, the count of the timer 50 started in step 208 is stopped and the count value is reset, thereby ending registration mark detection timing monitoring.

  In the control unit 48, the interruption process shown in FIG. 6 is executed, and the process proceeds to step 300 (exposure start timing adjustment value calculation control).

  In step 300, it is determined whether or not a stop signal for stopping the conveyance of the continuous paper 12 is input from the input unit 46. If the determination is negative, the routine is terminated. If the determination is affirmative, the process proceeds to step 302.

  In step 302, a conveyance stop signal as a stop signal for stopping conveyance of the continuous paper 12 in the conveyance direction is output to the continuous paper conveyance unit 54. In the continuous paper conveyance unit 54, when a conveyance stop signal is input, an unfixed image (toner image) on the continuous paper 12 transferred by the photoconductor 20 and fixed to the continuous paper 12 is fixed. After continuing the conveyance so that the image forming position is conveyed to the fixing device 22, the conveyance in the conveyance direction is stopped.

  Even if a conveyance stop signal for stopping the conveyance of the continuous paper 12 is input by the processing in step 302, the unfixed image transferred to the continuous paper 12 can be fixed to the continuous paper 12. .

  In the next step 304, the expected value is read from the memory 52, and a reverse conveyance instruction for conveying the continuous paper 12 in the reverse conveyance direction by an amount corresponding to the read expected value is output to the conveyance control unit. When a reverse conveyance instruction is input to the continuous paper conveyance unit 54, the drive roller 24 and the back tension roller 26 convey the amount of continuous paper 12 corresponding to the expected value in the reverse conveyance direction. When the continuous paper 12 is conveyed in the opposite conveyance direction opposite to the conveyance direction B, the drive roller 24 is controlled to rotate at a slower speed than the back tension roller 26.

  Here, when the continuous paper 12 is transported in the opposite transport direction after the transport in the transport direction is stopped, if the continuous paper 12 is transported ideally, it continues until the next image formation start position. Although the paper 12 is returned, an expected value in which the amount by which the continuous paper 12 is actually returned is set due to factors such as conveyance deviation when the continuous roller 12 is conveyed in the opposite conveyance direction by the drive roller 24 and the back tension roller 26. Depending on the amount, it may be different.

  In the next step 308, the continuous paper 12 measured by the continuous paper movement amount measuring unit 42 for measuring the movement amount of the continuous paper 12 in the non-conveyance direction when the continuous paper 12 is conveyed in the non-conveyance direction. In the next step 310, it is determined whether or not the read movement amount is equal to the preset expected value. If the result is affirmative, this routine is terminated and the result is negative. Then, the process proceeds to step 312.

  In step 312, it is determined whether or not the movement amount read in step 308 is less than or equal to a preset expected value. If the determination is affirmative, the process proceeds to step 314, where a value obtained by subtracting the movement amount from the expected value is The exposure timing adjustment value is corrected by subtracting it from the exposure timing adjustment value stored in the memory 52.

  On the other hand, when the result in step 312 is negative, the routine proceeds to step 316, where the exposure timing adjustment value is corrected by subtracting the value obtained by subtracting the expected value from the movement amount from the actual exposure timing adjustment value, and then this routine is terminated. To do.

  If the amount of movement actually moved during the reverse conveyance of the continuous paper 12 by the processing of step 314 and step 316 is less than or equal to a preset expected value, the exposure timing is determined according to the difference between the expected value and the amount of movement. The adjustment value can be corrected.

  As described above, according to the image forming apparatus 10 of the present invention, a predetermined conveyance amount is set so that the continuous paper 12 is returned to the next image formation start position after the conveyance of the continuous paper 12 is stopped. The anti-continuity of the continuous paper 12 measured by the continuous paper movement amount measuring unit 42 for measuring the expected value and the movement amount of the continuous paper 12 in the anti-conveyance direction when the continuous paper 12 is conveyed in the anti-conveyance direction. Since the exposure timing adjustment value for adjusting the image formation start position calculated based on the detection result of the registration mark 40 can be corrected according to the difference from the movement amount in the transport direction, the continuous paper 12 Even after the position is returned, the image forming position of the image forming apparatus 10 can be adjusted with high accuracy.

1 is a diagram showing an outline of an image forming apparatus of the present invention. It is a schematic diagram which shows an example of the registration mark currently formed on the continuous paper. 1 is a block diagram showing an outline of an image forming apparatus according to an embodiment of the present invention. It is a flowchart which shows the process performed by a control part. It is a flowchart which shows the process performed by a control part. It is a flowchart which shows the interruption process performed by a control part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 16 Mark detection sensor 42 Continuous paper movement amount measurement part 48 Control part 54 Continuous paper conveyance part

Claims (4)

Transport means for transporting continuous paper in which a reference mark is formed in advance in the transport direction;
Image forming means for starting image formation on the continuous paper based on an input of an image formation start instruction signal;
Detecting means for detecting the reference mark formed on the continuous paper;
An arithmetic unit that calculates an adjustment value for adjusting an image formation start position on the continuous paper based on a detection result by the detection unit;
An output means for outputting the image formation start instruction signal to the image forming means based on the calculated adjustment value;
When a stop signal for stopping the conveyance of the continuous paper in the conveyance direction is input, the continuous paper is conveyed to a predetermined position and stopped, and then the continuous image is formed until the next image formation start position. A transport control means for controlling the transport means so as to return the continuous paper a predetermined transport amount so that the paper is returned;
Measuring means for measuring the amount of movement of the continuous paper in the non-conveyance direction from when the conveyance is stopped until it is returned to the formation start position of the next image;
Correction means for correcting the adjustment value according to the difference between the movement amount measured by the measurement means and the transport amount;
An image forming apparatus.   The conveyance control unit conveys the continuous paper to a position where the image is fixed by a fixing unit that fixes the image formed by the image forming unit to the continuous paper, and then stops conveyance. The image forming apparatus according to claim 1, wherein the transport unit is controlled to return the transport amount of the continuous paper so that the continuous paper is returned to a formation start position.   The image forming apparatus according to claim 1, wherein the continuous paper is a pinless continuous paper having no conveyance hole.   The image according to any one of claims 1 to 3, wherein the correction unit corrects the difference obtained by subtracting a movement amount measured by the measurement unit from the transport amount, by adding the difference to the adjustment value. Forming equipment.

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