JP6128144B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that considers an elapsed time until the conveyance of continuous paper or the like is stabilized in the image forming apparatus.

  In recent years, image forming systems for forming images on continuous paper such as roll paper and perforated continuous form paper (continuous form paper) have been developed. The image forming system includes a paper feeder that supplies paper, an image forming machine that forms an image on the paper from the paper feeder, that is, a paper receiver that receives the paper from the image creator, and a paper feeder. And a control unit that controls operations of the paper machine, the image forming machine, and the paper receiver. There are various image forming apparatuses such as an electrophotographic system, an ink jet system, and a dot impact system.

  For example, Patent Document 1 discloses that tension is applied to continuous paper when the continuous paper is conveyed in the image forming system.

  In addition, in the image forming system, continuous paper is positioned during conveyance, so that the tension rollers are aligned, and position correction such as edge guider and EPC (edge position control: ear position control device) is used. The paper edges are evenly aligned by the device. Furthermore, side guides and collar rollers are used to determine the paper position.

  On the other hand, the continuous paper fluctuates in the width direction due to the influence of the tension (conveyance pressure). For example, the change of the conveyance pressure occurs due to the exchange of the conveyance parts, and the continuous paper fluctuates in the width direction. In addition, when the fixing device performs a fixing pressure separation operation, since the change in the conveyance pressure is large, the continuous paper also fluctuates in the width direction. In addition, when a continuous paper is newly set in the image forming apparatus, that is, when the paper is passed, if the continuous paper is newly transported, the continuous paper fluctuates in the width direction. This is because continuous paper is usually set manually in the image forming apparatus by hand, but it is very difficult to manually set continuous paper at the stable conveyance position.

  Since these fluctuation fluctuations are sine wave damped oscillations, they are converged and stabilized when a certain amount of continuous paper is conveyed. Therefore, in the conventional image forming apparatus, image formation (also referred to as image formation or printing) can be performed at a fixed position without shifting the image position of continuous paper. The paper was transported without image formation.

JP 2008-233770 A

  However, the roll paper must be conveyed by a predetermined length (for example, 4 to 5 meters) until the fluctuation of the roll paper in the width direction converges and stabilizes.

  Therefore, in the conventional image forming apparatus, a predetermined length of time is required after the image forming machine forms an image on the roll paper after confirming that the continuous paper is stably conveyed based on the paper position sensor. There is a possibility that the roll paper will be wasted, that is, it will become scraped paper. This is a problem in terms of cost and also from the viewpoint of resource utilization.

  Accordingly, the present invention provides an image forming apparatus, an image forming apparatus control method, and a program capable of reducing the amount of splinter paper even when the position of the continuous recording material vibrates in the width direction at the start of conveyance.

  An image forming apparatus according to an aspect of the present invention measures an image forming unit that forms an image on a continuous recording material, and a position in a width direction orthogonal to the conveyance direction of the continuous recording material conveyed to the image forming unit. The image forming unit starts image formation based on the position sensor that detects the position in the width direction of the continuous recording material measured by the position sensor and the image data that is formed on the continuous recording material by the image forming unit. And a control unit for controlling time.

Preferably, the position sensor is provided on the upstream side of the image forming unit.
Preferably, when the control unit determines that the change in the width direction of the continuous recording material is stable based on the position measurement data and the image data, the control unit starts image formation of the image forming unit.

  Preferably, when the length of the image data in the width direction is short, the control unit determines that the amount of change in the width direction of the continuous recording material based on the position measurement data is equal to or less than the first amount of change. When the image data is started and the length of the image data in the width direction is long, the change amount in the width direction of the continuous recording material based on the position measurement data is equal to or less than the second change amount smaller than the first change amount. When it is determined that the image forming unit has started, the image forming unit starts image formation.

  Preferably, when the length of the image data in the width direction is long based on the position measurement data, the control unit sets the image formation start time of the image forming unit as compared with the case where the length of the image data in the width direction is short. Slow down.

  Preferably, the control unit determines the image forming position of the image forming unit in the width direction with respect to the continuous recording material based on the position measurement data.

  Preferably, the control unit calculates a change amount and a change period in the width direction of the continuous recording material based on the position measurement data, and controls an image forming start time of the image forming unit based on the size of the image data. .

  Preferably, the control unit adjusts the image formation start time of each image data based on a plurality of image data having different lengths in the width direction.

  Preferably, the control unit adjusts the start time so that image formation of image data having a short length in the width direction is started by the image forming unit prior to image data having a long length in the width direction.

  Preferably, the control unit predicts a time during which the change in the width direction of the continuous recording material is stabilized based on the position measurement data and the image data, and starts image formation of the image forming unit based on the prediction result.

  An image forming apparatus control method according to an aspect of the present invention includes: a step of forming an image on a continuous recording material; a step of measuring a position in a width direction orthogonal to a conveyance direction of the continuous recording material; And a step of controlling an image forming start time based on position measurement data indicating a position in the width direction of the recording material and image data to be imaged on the continuous recording material.

  A program according to an aspect of the present invention is a program executed by a computer of an image forming apparatus, wherein the program forms an image on a continuous recording material on the computer, and is orthogonal to a conveyance direction of the continuous recording material. A step of measuring the position in the width direction to be performed, and a step of controlling the start time of image formation based on the position measurement data indicating the measured position in the width direction of the continuous recording material and image data to be imaged on the continuous recording material The process is executed.

  The present invention can reduce the amount of splinter paper even if the continuous paper position vibrates in the width direction at the start of conveyance.

1 is a diagram illustrating a schematic configuration of an image forming system 40 based on Embodiment 1. FIG. It is a block diagram explaining the function of the control part 70 based on Embodiment 1. FIG. It is a figure explaining the fluctuation | variation which the roll direction of the roll paper 18 based on Embodiment 1 shakes. 6 is a diagram illustrating a relationship between fluctuations in the width direction of the roll paper 18 and image data based on the first embodiment. FIG. 2 is a flowchart for controlling the start of image formation in the image forming system based on Embodiment 1. FIG. It is a figure explaining the subroutine process of the stability determination process based on Embodiment 1. FIG. FIG. 10 is a flowchart for explaining image formation start of the image forming system 40 based on the second embodiment. FIG. 10 is a diagram for explaining the relationship between fluctuations in the width direction of a roll paper 18 and image data based on Embodiment 2. 10 is a diagram for explaining an example of calculating an allowable width based on the size of image data based on Embodiment 2. FIG. FIG. 10 is a diagram for explaining the order in which jobs are submitted based on Embodiment 3; It is a figure which shows the principle which calculates a stable time and a stable position with the relationship between the fluctuation width of the width direction of the roll paper 18 based on Embodiment 4, and time. FIG. 10 is a flowchart for controlling the start of image formation in an image forming system based on Embodiment 4.

  Embodiments will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is a diagram illustrating a schematic configuration of an image forming system 40 based on the first embodiment.

  Referring to FIG. 1, the image forming system 40 includes a paper feeder 14, an image creator 42, and a winder 16.

  The paper feeder 14 includes roll paper 18 as continuous paper. A paper feeder 14 for the roll paper 18 is provided upstream of the image forming machine 42. Further, a winder 16 that is a paper receiver is provided downstream of the image forming machine 42. The paper feeder 14 includes a receiving shaft 20 for the roll paper 18 and rollers 22 and 24 for tension and guide.

In the case of the electrophotographic system, the image forming machine 42 includes a plurality of image forming units.
Specifically, the image forming device 42 includes four image forming units 44Y, 44M, 44C, and 44K of yellow (Y), magenta (M), cyan (C), and black (BK). Hereinafter, the image forming unit 44 is also collectively referred to.

  Each image forming unit 44 includes photosensitive drums 46Y, 46M, 46C, and 46BK, and a charging unit, an exposure unit, and a developing unit (not shown). Hereinafter, the photosensitive drum 46 is also collectively referred to.

  Further, the image forming machine 42 includes a control unit 70 that controls each image forming unit 44, an intermediate transfer belt 47, rollers 48 and 50, a secondary transfer roller 54, a fixing unit 56, and a paper position sensor 60. including.

  Based on the Y, M, C, and BK image signals supplied from the control unit 70, the exposure unit scans the photosensitive drum 46 charged by the charging unit with a laser beam to form an electrostatic latent image.

The intermediate transfer belt 47 is stretched between the rollers 48 and 50.
The primary transfer rollers 52Y, 52M, 52C, and 52BK (hereinafter also collectively referred to as the primary transfer roller 52) are disposed so as to face the photosensitive drum 46 with the intermediate transfer belt 47 interposed therebetween, and are disposed on the surface of the photosensitive drum 46. The formed toner image is electrostatically attracted and transferred onto the intermediate transfer belt 47 (primary transfer).

  The toner image on the intermediate transfer belt 47 is transferred to the roll paper 18 sandwiched between the roller 48 and the secondary transfer roller 54 (secondary transfer).

  The toner image transferred to the roll paper 18 is fixed to the roll paper 18 by the fixing unit 56, and image formation (image formation) is completed.

  The image forming unit 44, the photosensitive drum 46, the intermediate transfer belt 47, the secondary transfer roller 54, and the like constitute an image forming unit 78.

  The winder 16 has a winding shaft 26 for the roll paper 18 and rollers 28 and 30 for tension and guide.

  The image forming system 40 of the present invention further includes a paper position sensor 60 inside the image forming machine 42.

  The position of the paper position sensor 60 may be on the downstream side in the paper conveyance direction of the image forming unit 78 (secondary transfer roller 54), that is, on the winder 16 side, but on the upstream side in the paper conveyance direction of the image forming unit 78. That is, the paper feeder 14 side is preferable. In the case of the upstream side, the paper position sensor 60 is simply provided upstream of the image forming device 42.

  The paper position sensor 60 measures the position of the roll paper 18 in the width direction and generates position measurement data. Therefore, the paper position sensor 60 may be a line sensor along the width direction of the roll paper 18 or a video camera. The position in the width direction of the roll paper 18 can be detected from the difference in brightness of the image data between the inside and outside of the end of the roll paper 18, and the detection information is generated as position measurement data. In the present embodiment, the width direction of the roll paper 18 refers to a direction orthogonal to the conveyance direction of the roll paper 18.

  In the first embodiment, the control unit 70 acquires position measurement data from the paper position sensor 60 and determines whether or not stable image formation is possible. The image forming unit 78 forms an image on the roll paper 18 according to an instruction from the control unit 70, that is, prints.

FIG. 2 is a block diagram illustrating functions of the control unit 70 based on the first embodiment.
Referring to FIG. 2, the control unit 70 includes a central processing unit (CPU) 72 and a memory 74, and these elements are interconnected by a bus.

  The CPU 72 is a microprocessor, a microcomputer, a limited use integrated circuit, or the like. The memory 74 includes a hard disk, a read only memory (ROM), a random access memory (RAM), and the like. The memory 74 stores an operating system such as Windows (registered trademark), a program for controlling the operation of the image forming system 40, and the like, and also operates as a temporary storage device.

  Within the controller 70, an input / output (I / O) device (not shown) is connected to the bus. Through this I / O device, the control unit 70 receives image data from the outside, position measurement data from the paper position sensor 60, and status data indicating the states of the fixing unit 56 and the image forming unit 78 in the image forming device 42. Receive.

  The operation display unit 76 includes an operation switch (or keyboard) and a display device, and an operator can perform control operations of the image forming device 42 and the like. The operation display unit 76 may be a touch panel type operation unit attached to the image forming device 42 or may be a computer input device or the like. Further, the control unit 70 controls the operations of the fixing unit 56 and the image forming unit 78 in accordance with the above-described program, command data from the operation display unit 76, and the like. This program also includes an image forming operation program described later according to the present invention.

FIG. 3 is a diagram for explaining fluctuation in the width direction of the roll paper 18 based on the first embodiment.
As shown in FIG. 3, the vibration in the width direction of the roll paper 18, that is, the relationship between the position of the end of the roll paper 18 (Y axis: mm) and time (X axis: second) is shown.

  Due to the above-described tension (conveyance pressure), the roll paper 18 fluctuates in the width direction at the start of conveyance.

At point S, the case where the conveyance of the roll paper 18 is started is shown.
The fluctuation of the roll paper 18 in the width direction attenuates in a sinusoidal manner from the maximum amplitude value as illustrated. Then, as shown in the region T, when the amplitude becomes a predetermined value, for example, it is possible to consider that the fluctuation fluctuation converges and is stable. This time is called the stable time, and the paper edge position corresponding to the amplitude is called the stable position. Note that the predetermined value can be appropriately changed by those skilled in the art.

The sheet position sensor 60 transmits position measurement data as shown in FIG.
The control unit 70 controls the image forming operation of the image forming system 40 based on the position measurement data in accordance with a program stored in the memory.

  FIG. 4 is a diagram for explaining the relationship between fluctuation in the width direction of the roll paper 18 and image data based on the first embodiment.

  4A and 4B show a case where the length in the width direction of the image is long and a case where the length is short.

  As shown in FIG. 4A, when the length of the image in the width direction is long, the image protrudes due to the influence of blurring fluctuation (image protrusion occurs).

  As shown in FIG. 4B, when the length in the width direction of the image is short, there is no influence on the image due to blurring fluctuation, and no image protrusion occurs (no image protrusion).

Therefore, the stabilization time differs based on the size of the image data.
In the first embodiment, the start time for starting image formation on the roll paper 18 is controlled based on the size (width direction) of the image data.

FIG. 5 is a flowchart for controlling the start of image formation in the image forming system according to the first embodiment.
As shown in FIG. 5, the printing operation is started (step S2). Specifically, the printing operation starts when the operator turns on the power switch of the image forming system 40. When the operator presses the print start button on the operation display unit 76, the printing operation of the image forming system 40 is started, and first, the conveyance of the roll paper 18 is started.

  Next, reading of the paper position sensor is started (step S4). Specifically, the paper position sensor 60 continuously starts measuring the position in the width direction of the roll paper 18 and sequentially sends the position measurement data to the control unit 70. In FIG. 3, the position measurement data is shown as an analog waveform, but it is actually corresponding digital data.

  Next, a stability determination process is executed (step S6). The stability determination process is a process for determining whether or not an image can be formed without causing an image protrusion based on the position measurement data and the image data. Details of the stability determination process will be described later.

  Then, after it is determined that image formation is possible after the processing in step S6, image formation is started (step S8).

Then, the process ends (END).
FIG. 6 is a diagram illustrating a subroutine process of the stability determination process based on the first embodiment.

The processing is mainly processing in the control unit 70.
As shown in FIG. 6, the image data size is confirmed (step S10). As the image data size, a width direction perpendicular to the transport direction is acquired based on image data from the outside.

  Next, position measurement data is acquired (step S12). Specifically, the position measurement data from the paper position sensor 60 is acquired.

  Next, the meandering width is calculated (step S14). The meandering width is calculated based on the acquired position measurement data shown in FIG.

  Next, an allowable width is calculated (step S16). As an example of the allowable width, for example, a length obtained by subtracting the meandering width from the length in the width direction of the roll paper 18 can be calculated as the allowable width.

  Then, it is determined whether or not stable image formation is possible (step S18). Specifically, it is determined whether or not the image can be formed without causing the image to protrude. In this respect, it is possible to determine whether or not image formation is possible without occurrence of image protrusion based on whether or not the length in the width direction of the image data is equal to or less than the allowable width calculated above. Is possible.

  If it is determined in step S18 that stable image formation is possible (YES in step S18), the process proceeds to the next step and image formation is started (step S8).

  On the other hand, if it is determined in step S18 that stable image formation is not possible (NO in step S18), the process returns to step S12 again, and this process is repeated until stable image formation is possible.

  As described above, the meandering width attenuates in a sinusoidal manner, and accordingly, the value of the allowable width increases. Therefore, when the length of the image data in the width direction is short, it is determined that stable image formation is possible at an early stage. On the other hand, when the length of the image data in the width direction is long, it is determined that stable image formation is possible when the meandering width is reduced.

  The image forming system according to the first embodiment controls the image formation start time based on the position measurement data and image data measured by the paper position sensor 60. Specifically, if the length of the image data in the width direction is short, it is determined that stable image formation is possible at an early stage after the conveyance is started, so the amount of waste paper can be reduced. It is. On the other hand, if the length of the image data in the width direction is long, it is judged that stable image formation is possible when the meandering width becomes small, and image quality is ensured without causing image protrusion. Is possible.

  In this example, the method for calculating the allowable width based on the calculation result of the meandering width has been described. However, the meandering width threshold that enables stable image formation is set to a long length in the width direction of the image data. It is also possible to set for each case and short case.

  For example, when the length of the image data in the width direction is long, it is determined that stable image formation is possible when the meandering width is equal to or smaller than the first threshold value. If it is short, it may be determined that stable image formation is possible when the meandering width is equal to or smaller than the second threshold (> first threshold).

  In this example, the method of calculating the allowable width based on the calculation result of the meandering width has been described. However, instead of calculating the allowable width, the stable time is estimated and the operation is performed when the stable time has elapsed. It may be determined that an image is possible.

  For example, when the length in the width direction of the image data is long, it is determined that stable image formation is possible when the first period has elapsed, and when the length in the width direction of the image data is short Alternatively, it may be determined that stable image formation is possible when the second period (<first period) has elapsed. The first period and the second period can be adjusted based on the calculated meandering width. For example, when the meandering width is large, the decay time is determined to be long, and when the meandering width is small, the decay time is determined to be short, and the first period and the second period are adjusted. good. That is, when the length of the image data in the width direction is short, the stabilization time is set shorter than when the width of the image data in the width direction is long (the image formation start time is set earlier). It is possible to reduce the amount of When the length of the image data in the width direction is long, the stabilization time is set longer than when the length of the image data in the width direction is short (the start time of image formation is delayed), so that the image protrudes. It is possible to ensure the image quality without causing the occurrence of the above.

(Embodiment 2)
FIG. 7 is a flowchart for explaining the start of image formation of the image forming system 40 based on the second embodiment.

  As shown in FIG. 7, the image formation start flow diagram based on the second embodiment is different from FIG. 5 in that step S <b> 7 is further added. Other configurations are the same.

  Specifically, the writing position is calculated after the stability determination process (step S7). Specifically, the control unit 70 processes the position measurement data, and calculates the writing position (image forming position) of the roll paper 18 in the main scanning direction in accordance with the change in the paper position.

Then, image formation is started (step S8).
Even when the paper is meandering in the width direction by the processing, the position of the image data from the edge of the paper can be made constant.

  FIG. 8 is a diagram for explaining the relationship between fluctuation in the width direction of the roll paper 18 and image data based on the second embodiment.

  FIGS. 8A and 8B show a case where the length in the width direction of the image described in FIGS. 4A and 4B is long and a case where it is short. Moreover, the case where the length of the length direction of an image is both short is shown.

  As shown in the figure, when the image writing position is calculated in accordance with the width of the meandering in the width direction and the image formation is started, the image is formed in accordance with the meandering, so that the image may not protrude. It is shown.

  On the other hand, as shown in FIG. 8C, when the length in the length direction of the image is long as well as the width of the image, the protrusion of the image occurs due to the influence of blurring fluctuation.

  As shown in FIG. 8D, when the length in the width direction of the image is long but the length in the length direction of the image is short, there is no influence on the image due to blurring, and the image does not protrude. .

Therefore, the stabilization time differs based on the size of the image data.
In the second embodiment, the start time for starting image formation on the roll paper 18 is controlled based on the size (width direction and length direction) of the image data.

  FIG. 9 is a diagram for explaining an example of calculating the allowable width based on the size of the image data based on the second embodiment.

  As shown in FIG. 9, an approximate line Z that approximates the meander line at the end of the roll paper is calculated.

According to the approximate line Z, an allowable size of the image data is calculated.
For example, when the roll paper 18 is meandering with a meandering width W, if the image has a width X or less obtained by subtracting the meandering width W × 2 from the width of the roll paper 18, the influence of fluctuations on the image regardless of the length. There is no protrusion of the image.

  On the other hand, in the case of the length L in the length direction of the image, if the length in the width direction of the image is (X + W) −Ltanθ or less (allowable width), there is no influence on the image due to blurring variation, and the image protrudes. Is not expected to occur. As an example, it is defined as tan θ = (W + α) / (length of meander half-cycle). α is a predetermined value.

The length of the meandering half cycle is calculated by writing speed × meandering half cycle (meandering cycle H / 2).
Since the fluctuation (meandering) that is blurred attenuates in a sinusoidal manner, the allowable width increases with time. Then, based on the size of the image data, it is determined that stable writing is possible when the allowable range of the image size with respect to fluctuations in fluctuation is satisfied.

  The image forming system according to the second embodiment controls the start time of image formation based on position measurement data and image data (width direction and length direction) measured by the paper position sensor 60. Specifically, the allowable width is calculated based on the length in the width direction of the image data, and if it is equal to or smaller than the calculated allowable width, it is determined that stable image formation is possible at an early stage. Can be reduced.

(Embodiment 3)
In the third embodiment, processing when a plurality of jobs for executing image formation of a plurality of images is input will be described.

FIG. 10 is a diagram illustrating the job submission order based on the third embodiment.
As shown in FIG. 10A, a case is shown in which a job for printing image data having a long length in the width direction and a job for printing image data having a short length in the width direction are mixed. Yes.

  For example, a case where a job JOB1 for printing image data having a long length in the width direction and jobs JOB2 and JOB3 for printing image data having a short length in the width direction are reserved in the image forming system 40 is shown. . Specifically, it is assumed that a plurality of jobs are input to the control unit 70 from the outside, and a job that prints image data whose length in the width direction is longer than a predetermined threshold based on the image data of each job; The job order is changed by classifying the image data into a job for printing short image data whose length in the width direction is a predetermined threshold value or less.

  In the third embodiment, when a plurality of jobs are reserved, the job order is changed. In this example, jobs JOB2 and JOB3 are prioritized over job JOB1 and printing is performed. By changing the order of the jobs, for example, as shown in FIG. 10B, the print operation for jobs JOB2 and JOB3 is started before the first job JOB1.

  By executing the process of changing the order of the reserved jobs based on the size of the job, it is possible to form an image from an image with less influence on the image of fluctuation fluctuation. Thereby, it is possible to start image formation at an early stage, and it is possible to reduce the amount of deviation.

(Embodiment 4)
In the fourth embodiment, based on the position measurement data from the paper position sensor 60, before the change in the width direction of the roll paper 18 is actually stabilized, the stabilization time and the stable position are calculated, and the image forming device 42 is configured. A method for controlling the image operation will be described. For this operation, before calculating the stabilization time and the stable position, it is necessary to obtain in advance an attenuation profile related to attenuation of the change in the width direction of the continuous paper.

  FIG. 11 is a diagram illustrating the principle of calculating the stable time and the stable position based on the relationship between the width of the roll paper 18 in the width direction and time based on the fourth embodiment.

  As shown in FIG. 11, the point A (coordinates xA, yA) of the attenuation waveform is a point where the change in the width direction of the roll paper 18 is stable, that is, a converged point, so the value xA in the time axis direction is stable. Time is indicated, and a value yA in the paper edge position axis direction indicates a stable position.

  A straight line L1 passing through the inflection point B1 (coordinates x1, y1), the inflection point B2 (coordinates x2, y2) and the point A (coordinates xA, yA) of the attenuation waveform may be expressed as y = ax + b (1). it can. Similarly, the straight line L2 passing through the inflection point B3 (coordinates x3, y3), the inflection point B4 (coordinates x4, y4) and the point A (coordinates xA, yA) of the attenuation waveform is expressed as y = cx + d (2 ). Therefore, the stable point A is the intersection of these straight lines L1 and L2. The slopes (a, c) of the above formulas (1) and (2) are called attenuation profiles.

  If the inflection points B1 to B4 and the stable point A of the attenuation waveform are obtained in advance from the position measurement data, a and b of the straight line L1 and c and d of the straight line L2 can be obtained in advance.

  The attenuation profile may be stored as a table TB in the memory 74 of the control unit 70 when the image forming device 42 is shipped from the factory.

  When the attenuation profile of the roll paper 18 is obtained, the control unit 70 can calculate the straight lines L1 and L2 by obtaining the coordinate values of the inflection points B1 to B4 from the paper position data from the paper position sensor 60. Therefore, before the attenuation curve is stabilized, for example, in the time when the position measurement data up to the inflection point B2 is obtained, the coordinates of the stable point A after the inflection point B2 can be calculated and predicted.

  FIG. 12 is a flowchart for controlling the start of image formation in the image forming system according to the fourth embodiment.

  As shown in FIG. 12, printing is started (step S20). Specifically, the printing operation starts when the operator turns on the power switch of the image forming system 40. When the operator presses the print start button on the operation display unit 76, the printing operation of the image forming system 40 is started, and first, the conveyance of the roll paper 18 is started.

  Next, the image data size is confirmed (step S22). As the image data size, a width direction perpendicular to the transport direction is acquired based on image data from the outside.

  Next, reading of the paper position sensor is started (step S24). Specifically, the paper position sensor 60 continuously starts measuring the position in the width direction of the roll paper 18 and sequentially sends the position measurement data to the control unit 70.

  Next, position measurement data is acquired (step S26). Specifically, the position measurement data from the paper position sensor 60 is acquired.

  Next, an attenuation prediction is calculated based on the attenuation line (step S28). As described above, an attenuation curve is calculated based on the attenuation profile.

  Next, the start timing is determined (step S30). The start timing is determined based on the image data. The meandering width can be predicted based on the calculated attenuation curve. The timing at which the length in the width direction of the image data is equal to or less than the allowable width calculated above is determined as the start timing with the length obtained by subtracting the meandering width from the length in the width direction of the roll paper as the allowable width.

  Next, it is determined whether or not the start timing has been reached (step S32). It is determined whether or not the determined start timing has been reached according to the calculated attenuation polarity.

  If it is determined in step S32 that the start timing has been reached (YES in step S32), image formation is started (step S34).

Then, the process ends (END).
On the other hand, when it is determined in step S32 that the start timing has not been reached (NO in step S32), the state of step S32 is maintained.

  As described above, the meandering width attenuates in a sinusoidal manner, and accordingly, the value of the allowable width increases. Accordingly, when the length of the image data in the width direction is short, the start timing is determined as being possible to form an image stably at an early stage. On the other hand, when the length of the image data in the width direction is long, the start timing is determined on the assumption that stable image formation is possible when the meandering width is reduced.

  The image forming system according to the fourth embodiment calculates an attenuation curve based on the position measurement data and image data measured by the paper position sensor 60, and predicts the meandering width. The start time is controlled based on the prediction of the meandering width. Specifically, if the length of the image data in the width direction is short, it is determined that stable image formation is possible at an early stage after the conveyance is started, so the amount of waste paper can be reduced. It is. On the other hand, if the length of the image data in the width direction is long, it is judged that stable image formation is possible when the meandering width becomes small, and image quality is ensured without causing image protrusion. Is possible.

  In the above description, the case where image formation is started by the image forming unit 78 when it is determined by the control unit 70 that stable image formation is possible has been described. An image forming preparation operation may be performed before the vibration converges. That is, the exposure unit exposes the photosensitive drum 46 to form an electrostatic latent image. Further, a toner image corresponding to the electrostatic latent image is transferred to the intermediate transfer belt 47. The operation so far is performed before the actual convergence of the damped vibration of the roll paper 18. As soon as the stable time for the damping vibration of the roll paper 18 to converge is reached, the toner image on the intermediate transfer belt 47 is transferred to the roll paper 18 and image formation is performed. Thereby, the image formation on the roll paper 18 is completed. Therefore, the waste paper can be greatly reduced.

  Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, various modifications and changes can be made without departing from the spirit of the present invention. For example, in addition to the electrophotographic system, the image forming machine may be an ink jet system or a dot impact system as long as it uses continuous paper. Since these methods are well known, detailed description thereof is omitted.

  In the above-described embodiment, the example in which the roll paper 18 is used as the continuous paper has been described. However, the present invention is applied even when other continuous paper such as continuous paper with perforations (continuous paper) is used. can do. Furthermore, it is not limited to paper, and any recording material (continuous recording material) that can be printed may be used. For example, a film-like recording material can be similarly applied.

  Further, as a program in the present embodiment, an application that can be executed by a computer of the image forming apparatus may be provided. At this time, the program according to the present embodiment may be incorporated as a partial function of various applications executed on the personal computer.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  14 paper feeder, 16 winder, 18 roll paper, 20 receiving shaft, 26 take-up shaft, 40 image forming system, 42 image forming machine, 44 image forming unit, 46 photoconductor drum, 47 intermediate transfer belt, 52 primary Transfer roller, 54 Secondary transfer roller, 56 Fixing unit, 60 Paper position sensor, 70 Control unit, 74 Memory, 76 Operation display unit, 78 Image forming unit.

Claims (7)

An image forming unit for forming an image on a continuous recording material;
A position sensor that measures a position in the width direction orthogonal to the conveyance direction of the continuous recording material conveyed to the image forming unit;
Based on position measurement data indicating the position in the width direction of the continuous recording material measured by the position sensor and image data formed on the continuous recording material by the image forming unit, start of image formation of the image forming unit A control unit for controlling time ,
When the control unit determines that the change in the width direction of the continuous recording material is stable based on the position measurement data and the image data, it starts image formation of the image forming unit,
When the length of the image data in the width direction is short, when it is determined that the amount of change in the width direction of the continuous recording material based on the position measurement data is equal to or less than the first amount of change, the image forming unit Start
When the length of the image data in the width direction is long, it is determined that the change amount in the width direction of the continuous recording material based on the position measurement data is equal to or less than the second change amount that is smaller than the first change amount. In the case, the image forming apparatus starts image forming of the image forming unit. An image forming unit for forming an image on a continuous recording material;
A position sensor that measures a position in the width direction orthogonal to the conveyance direction of the continuous recording material conveyed to the image forming unit;
Based on position measurement data indicating the position in the width direction of the continuous recording material measured by the position sensor and image data formed on the continuous recording material by the image forming unit, start of image formation of the image forming unit A control unit for controlling time,
The control unit starts image formation of the image forming unit when the width in the width direction of the image data is long based on the position measurement data, compared to when the length in the width direction of the image data is short. An image forming apparatus that slows down time . An image forming unit for forming an image on a continuous recording material;
A position sensor that measures a position in the width direction orthogonal to the conveyance direction of the continuous recording material conveyed to the image forming unit;
Based on position measurement data indicating the position in the width direction of the continuous recording material measured by the position sensor and image data formed on the continuous recording material by the image forming unit, start of image formation of the image forming unit A control unit for controlling time,
The control unit adjusts the image formation start time of each image data based on a plurality of image data having different lengths in the width direction,
The control unit adjusts a start time so that image formation with a short length in the width direction is started by the image forming unit before image data with a long length in the width direction . The image forming apparatus according to claim 1, wherein the position sensor is provided on an upstream side of the image forming unit. The image forming apparatus according to claim 1, wherein the control unit determines an image forming position of the image forming unit in a width direction with respect to the continuous recording material based on the position measurement data. The control unit calculates a change amount and a change period in the width direction of the continuous recording material based on the position measurement data, and determines an image formation start time of the image forming unit based on the size of the image data. The image forming apparatus according to claim 1, wherein the image forming apparatus is controlled. The control unit predicts a time during which a change in the width direction of the continuous recording material is stabilized based on the position measurement data and the image data, and starts image formation of the image forming unit based on a prediction result. The image forming apparatus according to claim 1 .

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