JP2019181698A - Image formation apparatus and program - Google Patents

Abstract

Provided is an image forming apparatus and the like that can perform printing while suppressing deterioration in image quality and productivity even when a print job in which an image magnification is changed during printing is input. . A first scaling unit and a second scaling unit are combined so that a predetermined image magnification is obtained by combining a scaling ratio of a first scaling unit and a scaling ratio of a second scaling unit. A scaling factor for each of the means is determined. A print job in which an image magnification change occurs during printing and at least one of the image magnifications before and after the image magnification change exceeds an appropriate range of the magnification ratio of the first magnification unit. When the first and second magnification units are respectively changed, the first and second magnification units for the first image before the image magnification change and the second image after the image magnification change are the first image. And before printing the second image. [Selection diagram] FIG.

Description

  The present invention relates to an electrophotographic copying machine, a printer, a facsimile, and an image forming apparatus such as an MFP (Multi Function Peripheral) which is a multi-function digital multifunction peripheral having these functions, and a program.

  As an image forming apparatus as described above, an apparatus having an image scaling function by image processing and an image scaling function by adjusting the speed of a polygon mirror is known.

  In addition, depending on the output format of the image, for example, the image quality priority mode or the productivity priority mode, the monochrome mode or the color mode, etc. Techniques have been proposed in which at least one of the magnification functions is selected and image magnification adjustment is performed (for example, Patent Documents 1 and 2).

  By the way, a print job in which a change in image magnification occurs during printing may be submitted. For example, this is a case where the image magnification change is set only on the back side in duplex printing.

  In this case, if the image magnification on the back surface is too large or too small, the image quality may be deteriorated when the image on the back surface is scaled using the image scaling function by image processing. The reason for this is that the image scaling function using image processing has an appropriate range of scaling ratios that can be scaled while maintaining the image quality. If scaling outside the appropriate range is performed, the image quality deteriorates. It is to do.

  On the other hand, when trying to change the size of the back image using the image scaling function by adjusting the speed of the polygon mirror, in particular, in a configuration in which image writing of a plurality of colors (for example, two colors or four colors) is performed with one polygon mirror, Since it is necessary to adjust the speed at the time of zooming after writing of a plurality of colors and a certain time is required until the speed after the adjustment becomes stable, the productivity is lowered.

  Therefore, it has been proposed to realize a predetermined magnification by combining a scaling factor in an image scaling function by image processing and a scaling factor in an image scaling function by adjusting the speed of a polygon mirror.

JP 2012-86465 A JP 2012-123265 A

  However, when combining the scaling factor by image processing and the scaling factor by adjusting the speed of the polygon mirror, conventionally, each scaling factor in both scaling factors is determined by considering only the rear side image magnification to be changed. Therefore, when switching to the printing of the image on the back side, a large speed adjustment of the polygon mirror is inevitable, and a reduction in productivity is inevitable.

  The present invention has been made in view of such a technical background, and even when a print job in which a change in image magnification occurs in the middle of printing is input, image quality is deteriorated and productivity is lowered. An object of the present invention is to provide an image forming apparatus and a program capable of performing printing while suppressing the above-described problem.

The above object is achieved by the following means.
(1) A first scaling unit capable of scaling an image by image processing and having an appropriate range for a set scaling factor, and a second scaling unit capable of scaling the image by adjusting the speed of a polygon mirror And the first scaling unit and the second scaling unit so that a predetermined image magnification is obtained by combining the scaling factor of the first scaling unit and the scaling factor of the second scaling unit. Determining means for determining the respective scaling ratios, wherein the determining means is a print job in which a change in image magnification occurs during printing, and at least one image magnification before or after the change in image magnification However, when a print job exceeding the appropriate range of the scaling ratio of the first scaling unit is input, the first image before the change of the image magnification and the second image after the change are changed. Each scaling factor of the first scaling unit and the second scaling unit An image forming apparatus characterized by predetermining before printing the first image and the second image.
(2) The determining means is configured so that, before and after the change of the image magnification, the magnification of the first scaling means is within the appropriate range, and the amount of change of the magnification of the second scaling means is 2. The image forming apparatus according to item 1, wherein each of the first scaling unit and the second scaling unit is determined so as to be reduced.
(3) The determining means includes the first scaling means and the second scaling means so that the scaling ratio of the second scaling means is the same before and after the change of the image magnification. 3. The image forming apparatus according to item 2, wherein each magnification is determined.
(4) The image forming apparatus according to (1), wherein the determining unit determines a set value that deviates from the appropriate range as a scaling factor of the first scaling unit.
(5) Necessary when changing the non-image area interval T1 when the image magnification is changed and the magnification of the second magnification unit before changing the image magnification to the magnification after changing the image magnification. A calculation unit that calculates a non-image region interval T2, and the calculation unit calculates one or more intervals T1 and T2, and the determination unit compares the calculated interval T1 and interval T2. 5. The image forming apparatus according to any one of the preceding items 1 to 4, wherein each of the first scaling unit and the second scaling unit is determined based on the first and second scaling units.
(6) The image forming apparatus according to any one of Items 1 to 5, wherein the print job in which the image magnification is changed during printing is a print job in which the image magnification is different between the front surface and the back surface in the case of duplex printing.
(7) The print job in which an image magnification change occurs during printing is a print job for printing on a recording sheet fed from a plurality of paper feed trays, and is set for each paper feed tray to be used. 6. The image forming apparatus as described in any one of 1 to 5 above, wherein the image magnification is one or a plurality of different print jobs.
(8) The print job in which a change in image magnification occurs during printing is a print job for printing on a recording sheet of a plurality of paper types, and one or a plurality of image magnifications set for each paper type to be used. 6. The image forming apparatus as described in any one of 1 to 5 above, which is a different print job.
(9) When it becomes necessary to print a pattern outside the print area without scaling for image stabilization processing after changing the image magnification, the determining means sets the scaling ratio of the second scaling means as , It is determined that the magnification before printing of the pattern outside the print area is to be used continuously, and there is no magnification by combining the magnification of the first magnification unit and the magnification of the second magnification unit. 9. The image forming apparatus as described in any one of 1 to 8 above, which determines a scaling factor of the first scaling unit.
(10) When the print job is started in a state where only a part of the used paper feed trays is confirmed, the first scaling unit and the second power supply unit including the unused paper feed trays are also included. 8. The image forming apparatus according to item 7, wherein each magnification ratio of the scaling means is determined in advance before printing the first image and the second image.
(11) When the print job is started in a state where only some of the used paper types are determined, the first scaling unit and the second scaling unit including the unused paper types are included. 9. The image forming apparatus according to item 8, wherein each of the scaling factors is determined in advance before printing the first image and the second image.
(12) A first scaling unit capable of scaling an image by image processing and having an appropriate range for a set scaling factor, and a second scaling unit capable of scaling the image by adjusting the speed of a polygon mirror The first scaling unit so that a predetermined image magnification can be obtained by combining a scaling factor of the first scaling unit and a scaling factor of the second scaling unit in a computer of the image forming apparatus. A print job in which a step of determining a scaling factor of each of the scaling unit and the second scaling unit is executed, and a change in image magnification occurs during printing, and at least one before or after the change of the image magnification When a print job having an image magnification exceeding the appropriate range of the magnification of the first scaling unit is input, each of the first image before the change of the image magnification and the second image after the change Said first scaling means relative to Each magnification of the second zoom means, the first image and the program for executing a process of pre-determined before printing the second image.

  According to the invention described in (1) above, the first scaling unit is configured to obtain a predetermined image magnification by combining the scaling factor of the first scaling unit and the scaling factor of the second scaling unit. And the respective scaling ratios of the second scaling means are determined. A print job in which a change in image magnification occurs during printing, wherein at least one of the image magnifications before or after the change of the image magnification exceeds an appropriate range of the magnification ratio of the first scaling unit Is input, the respective scaling factors of the first scaling unit and the second scaling unit for the first image before the change of the image magnification and the second image after the change are respectively the first scaling factor. Before printing the second image and the second image.

  That is, not only the second image after the change of the image magnification but also the first image before the change of the image magnification, the respective scaling factors of the first scaling unit and the second scaling unit are Since it is determined in advance before the printing of the first image and the second image, the degree of freedom of setting the scaling factor is increased, and while securing the set value within an appropriate range as the scaling factor of the first scaling unit, The scaling factor of the second scaling unit can be set so that the scaling factor does not change greatly when the image magnification is changed. As a result, even when a print job in which a change in image magnification occurs during printing is input, it is possible to suppress image quality deterioration and productivity reduction.

  According to the invention described in (2) above, before and after the change of the image magnification, the magnification of the first magnification unit is within an appropriate range, and the amount of change of the magnification of the second magnification unit Since the respective scaling factors of the first scaling unit and the second scaling unit are determined so as to decrease, the effect of suppressing the deterioration of the image quality and the decrease in productivity becomes large.

  According to the invention described in (3) above, the first scaling unit and the second scaling unit are set so that the scaling factor of the second scaling unit is the same before and after the change of the image magnification. Since the respective scaling ratios of the means are determined, the effect of suppressing deterioration in image quality and reduction in productivity is further increased.

  According to the invention described in item (4) above, since the set value that deviates from the appropriate range is determined as the scaling factor of the first scaling unit, the productivity is greatly reduced while the effect of suppressing the deterioration of image quality is reduced. Can be suppressed.

  According to the invention described in (5) above, the non-image area interval T1 when the image magnification is changed and the magnification of the second magnification unit before the image magnification is changed are changed to the magnification after the change of the image magnification. Since the respective scaling factors of the first scaling unit and the second scaling unit are determined on the basis of the comparison of the interval T2 of the non-image area required when changing to It is possible to determine the scaling factor that brings about the effect of suppressing the decrease in the above.

  According to the invention described in the preceding item (6), it is possible to suppress deterioration in image quality and productivity in a print job in which image magnification is different between the front surface and the back surface in the case of double-sided printing.

  According to the invention described in (7) above, the print job is to print on a recording sheet fed from a plurality of paper feed trays, and the image magnification set for each paper feed tray is different by one or more. With respect to a print job, it is possible to suppress deterioration in image quality and productivity.

  According to the invention described in item (8) above, image quality degradation is caused for a print job for printing on a recording sheet of a plurality of paper types, in which one or a plurality of image magnifications set for each paper type are different. And the fall of productivity can be controlled.

  According to the invention described in item (9), when it is necessary to print a pattern outside the print area without scaling for image stabilization processing, the print area is set as the scaling ratio of the second scaling unit. The scaling factor before printing the outer pattern is continuously used, and the first scaling unit is configured so that there is no scaling by combining the scaling factor of the first scaling unit and the scaling factor of the second scaling unit. Since the magnification is determined, it is not necessary to switch the speed of the polygon mirror in the second magnification unit, and the stabilization process can be performed quickly.

  According to the invention described in (10) above, when the print job is started with only a part of the used paper feed trays determined, the first paper including the unused paper feed trays is used. Since the scaling ratios of the scaling unit and the second scaling unit are determined in advance before printing the first image and the second image, even when the paper feed tray to be used after the start of printing is determined. The reduction in productivity can be prevented by not changing the scaling factor of the second scaling unit in the middle of the print job.

  According to the invention described in the above item (11), when the print job is started with only a part of the used paper types determined, the first scaling including the unused paper types is also performed. Since the respective scaling ratios of the first scaling unit and the second scaling unit are determined in advance before the printing of the first image and the second image, even if the paper type used after the start of printing is determined, Thus, it is possible to prevent the productivity from being lowered by not changing the magnification of the magnification changing means in the middle of the print job.

  According to the invention described in the preceding item (12), the image can be scaled by image processing, and the image can be scaled by adjusting the speed of the first zooming means having the appropriate range for the scaling ratio and the polygon mirror. And a process for suppressing deterioration in image quality and productivity when a print job in which an image magnification change occurs during printing is input to a computer of an image forming apparatus having a second scaling unit. Can be executed.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. 1 is a block diagram illustrating an electrical configuration of an image forming apparatus. FIG. 4A shows the state of image formation when printing an image for each page on two sheets. FIG. 5A shows a case where no scaling occurs, and FIG. Shows the case. It is a figure for demonstrating the conventional determination method of the magnification of a 1st magnification means and a 2nd magnification means. It is a figure for demonstrating the determination method of the scaling factor of the 1st scaling unit and the 2nd scaling unit based on one Embodiment of this invention. It is a figure for demonstrating the modification of the determination method of the scaling factor of the 1st scaling unit and 2nd scaling unit demonstrated in FIG. It is a flowchart which shows the determination process of the magnification ratio of a 1st magnification means and a 2nd magnification means. It is a flowchart which shows the other determination process of the magnification ratio of the 1st magnification means and the 2nd magnification means. It is a flowchart which shows the further another determination process of the scaling factor of the 1st scaling unit and the 2nd scaling unit. It is a figure for demonstrating the magnification operation which a 1st magnification means and a 2nd magnification means perform with the magnification ratio determined by the flowchart shown in FIG. This is a screen for selecting whether to give priority to image quality or productivity when scaling on both sides. It is a figure for demonstrating the subject in the case of printing by changing the image magnification of 1 sheet of both sides. It is a flowchart which shows the further another determination process of the scaling factor of the 1st scaling unit and the 2nd scaling unit. It is a flowchart which shows the further another determination process of the scaling factor of the 1st scaling unit and the 2nd scaling unit. It is a flowchart which shows the further another determination process of the scaling factor of the 1st scaling unit and the 2nd scaling unit. It is a figure for demonstrating the subject at the time of printing the adjustment pattern for a stabilization process in the state in which the scaling by the 2nd scaling means has generate | occur | produced. It is a flowchart which shows the further another determination process of the scaling factor of the 1st scaling unit and the 2nd scaling unit. It is a flowchart which shows the further another determination process of the scaling factor of the 1st scaling unit and the 2nd scaling unit.

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

  FIG. 1 is a schematic configuration diagram of an image forming apparatus 1 according to an embodiment of the present invention. In this example, a tandem type color printer is used as the image forming apparatus 1.

  In FIG. 1, the image forming apparatus 1 is configured such that a sheet feeding unit 20 is disposed at the bottom of the apparatus main body 1A, the image forming unit 10 is disposed at the center, and a sheet discharge unit 60 is disposed at the top. The paper feed unit 20 includes a plurality of paper feed cassettes 21. The paper (recording sheet) S fed from the paper feed unit 20 is transported upward from each paper feed cassette 21 to the paper discharge unit 60. A conveyance path 22 is formed.

  The image forming unit 10 includes a driving roller 16 and a driven roller 15 disposed substantially at the center in the up-down direction of the apparatus main body 1A, and an intermediate portion that extends horizontally between the driving and driven rollers 16 and 15 and runs in the direction of the arrow. The transfer belt 14 and photosensitive units 12Y, 12M, 12C, which are image forming units for yellow (Y), magenta (M), cyan (C), and black (K), which are arranged along the running direction. 12K.

  The toner images created by the photoconductor units 12Y, 12M, 12C, and 12K are superimposed and transferred to the transfer belt 14, and the transfer end of the transfer belt 14 (see FIG. Secondary transfer is performed at the middle right end), and the sheet S is fed to the fixing unit 300 to fix the toner image. Further, in order to print on both sides of the paper S, a reverse conveyance path 90 is provided in which the paper S is reversed and travels.

 Each of the photoconductor units 12Y, 12M, 12C, and 12K forms an image by an electrostatic copying method, and includes a charger, a developing device 11Y, 11M, 11C, and 11K arranged around the photoconductor drum, and a photoconductor drum. 13Y, 13M, 13C, and 13K, a transfer device, and the like. The photosensitive drums 63Y, 63M, 63M, 63M, 63M, 63M, 63M, 63M, 63M, 63M, 63M, 63M, 63M, 63M, 63M The surfaces of 63C and 63K are exposed, and electrostatic latent images are formed on the surfaces.

  In this embodiment, one polygon mirror is used, and an image of four colors (electrostatic latent image) is formed by one polygon mirror. A configuration in which two polygon mirrors are used and a two-color image is formed by each polygon mirror may be used.

  Further, toner cartridges 70Y, 70M, 70C, and 70K and sub hoppers 80Y, 80M, 80C, and 80K are provided as a replenishment mechanism that replenishes toner to the developing units 11Y, 11M, 11C, and 11K of the photoreceptor units 12Y, 12M, 12C, and 12K. Is disposed above the photoconductor units 12Y, 12M, 12C, and 12K.

  In FIG. 1, reference numeral 50 denotes an operation panel unit including a key unit and a display unit.

  FIG. 2 is a block diagram illustrating an electrical configuration of the image forming apparatus 1. As shown in FIG. 2, the image forming apparatus 1 includes the control panel 100, the fixed storage device 110, the image reading device 120, the operation panel unit 50, the image forming unit 10, and the paper feeding unit 20 described above. A controller 150 and a network interface (network I / F) 160 are provided, and are connected to each other via a system bus 175.

  The control unit 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, an S-RAM (Static Random Access Memory) 103, an NV-RAM (Non Volatile RAM) 104, a clock IC 105, and the like.

  The CPU 101 performs overall control of the entire image forming apparatus 1 by executing an operation program stored in the ROM 102 or the like. For example, in addition to controlling the copy function, the printer function, the scan function, and the like to be executable, in this embodiment, in particular, when a print job in which a change in image magnification occurs during printing is input, the scaling factor and polygon by image processing are input. A scaling factor determination process is performed by adjusting the mirror speed, and a detailed description thereof will be described later.

  The ROM 102 stores programs executed by the CPU 101 and other data.

  The S-RAM 103 serves as a work area when the CPU 101 executes a program, and temporarily stores a program, data when the program is executed, and the like.

  The NV-RAM 104 is a non-volatile memory backed up by a battery, and stores various settings relating to image formation, the number of pixels of the display unit 134, data of various screens displayed on the display unit 134, and the like. .

  The clock IC 105 measures time and functions as an internal timer to measure processing time.

  The fixed storage device 110 includes a hard disk or the like, and stores programs, various data, and the like.

  The image reading device 120 includes a scanner or the like, reads a document set on a platen glass by scanning, and converts the read document into image data.

  The operation panel unit 50 is used when a user gives an instruction or various settings to the image forming apparatus 1 and includes a reset 51, a start key 52, a stop key 53, a display unit 54, a touch panel 55, and the like. ing.

  The reset key 51 is used when resetting the setting, the start key 52 is used for a start operation such as scanning, and the stop key 53 is pressed when the operation is interrupted. It is.

  The display unit 54 includes, for example, a liquid crystal display device and displays messages, various operation screens, and the like. The touch panel 55 is formed on the screen of the display unit 54 and detects a user's touch operation.

  The image forming unit 10 prints on a sheet a copy image generated from image data of a document read by the image reading device 120 or print data transmitted from an external operation. A motor 18 and a polygon mirror 19 are provided.

  The image processing unit 17 performs image processing on the print target data in accordance with the set print mode, and can scale the image. The polygon motor 18 rotates the polygon mirror 19, and the polygon mirror 19 reflects the light from the laser diode to expose the above-mentioned photosensitive drums 13Y, 13M, 13C, and 13K, and applies them to the respective photosensitive drums. An electrostatic latent image is formed. Also, by adjusting the rotational speed of the polygon mirror 19 via the polygon motor 18, the image can be scaled.

  Since the image scaling process by the image processing unit 17 and the image scaling process by adjusting the rotation speed of the polygon mirror 19 are both known techniques, detailed description thereof is omitted.

  The printer controller 150 generates a copy image from print data received by the network interface 160.

  The network interface (network I / F) 160 functions as a communication unit that transmits and receives data to and from an external terminal device.

  Next, the operation of the image forming apparatus 1 when a print job in which a change in image magnification occurs during printing is input will be described.

  As described above, the image forming apparatus 1 performs image scaling by the image processing of the image processing unit 17 (hereinafter also referred to as image processing scaling, which is also referred to as image processing scaling), and the speed of the polygon mirror 19. Image scaling by adjustment (hereinafter also referred to as polygon scaling, and the scaling factor is also referred to as a polygon scaling factor) is possible. In the image processing scaling, if the scaling ratio increases, the degradation of the image after scaling becomes conspicuous. For this reason, the image processing magnification is used in an inconspicuous range. That is, there is an appropriate range for the image processing magnification. In this embodiment, −1.0% to 1.0% is set as an appropriate range of the image processing magnification.

  On the other hand, there is no restriction on the appropriate range of magnification for polygon scaling, but it takes about 200 ms for the polygon mirror 19 to stabilize after speed adjustment. The time for stabilization increases as the speed adjustment amount increases. As described above, in this embodiment, four polygon images are formed by one polygon mirror 19. For this reason, productivity is reduced when scaling occurs between images. This will be described with reference to FIG.

  FIG. 3 shows the state of image formation when an image is printed one page at a time on two sheets of paper. FIG. 3 (A) shows a case in which scaling does not occur, and FIG. Each of the cases where doubling occurs is shown.

  3A and 3B, images of each color of yellow (Y), magenta (M), cyan (C), and black (K) are formed by shifting the writing start time and the end time. In FIG. 3A in which scaling does not occur, for each color image, after the writing of the image for the first page is completed, the normal paper interval time Ta has elapsed, and writing of the second page is started after the passage. The

  On the other hand, in the case of FIG. 3B in which scaling occurs between the image on the first page and the image on the second page, after the writing of the image on the first page of each color is completed, that is, an image of K color. After the writing is completed, the rotation of the polygon mirror 19 is adjusted, and the writing of the image of the next page is started after the elapse of time Tb (20 ms) until the rotation is stabilized. For this reason, the writing of the image of the next page is delayed by the time Tb until stabilization, and the productivity decreases accordingly.

  As described above, image processing scaling has restrictions on the appropriate range of the scaling ratio, and image quality deteriorates when the range is deviated. On the other hand, with the polygon scaling, there is a risk of reducing productivity.

  Here, even if a print job in which an image magnification change occurs during printing is input, if the image magnification to be changed is within the appropriate range of the image processing magnification, the image processing magnification is used. What is necessary is just to perform zooming. However, in the case of an image magnification that deviates from the appropriate range of the image processing magnification, if the magnification is changed only by the image processing magnification, the image quality deteriorates.

  Therefore, in this embodiment, the image processing magnification and the polygon magnification are combined, and the magnification of each magnification function is controlled so as to suppress the speed change of the polygon mirror 19 as much as possible before and after the change of the image magnification. To decide.

Next, taking a case where the print job that changes the image magnification during printing is a print job in which the image magnification differs between the front and back sides for double-sided printing, each of image processing scaling and polygon scaling A method of determining the scaling factor of will be described.
[Conventional example]
The appropriate range of magnification for image processing magnification is -1.0% to + 1.0%, the image magnification on the front side is 0.0% (no magnification), and the image magnification on the back side is -2.0% For scaling (reduction), first, a conventional determination method will be described with reference to FIG. Conventionally, as shown in the table of FIG. 4, since the surface image has no scaling, polygon scaling (simply referred to as polygon in FIG. 4), image processing scaling (simply referred to as image processing in FIG. 5). In any case, the scaling factor is determined to be + 0.0%. Also, the back side image is determined to have a scaling factor of -1.0% for polygon scaling and -1.0% for image processing scaling, and the total scaling factor by the combination of both scaling functions is -2. 0.0%, and an image magnification of -2.0% on the back side of the print job is secured.

  In this print job, printing is performed on a plurality of sheets in the order of front → back → front → back → front → back. However, as shown in the lower time chart of FIG. Both magnification and image processing scaling are 0%, and when switching from front to back printing, both polygon scaling and image processing scaling are switched to -1.0%.

  That is, since the change of polygon magnification occurs when switching from the front side to the back side printing, the speed of the polygon mirror 19 is changed, and a time until the polygon mirror 19 is stabilized at the changed speed is generated. Cause a decline.

In the time chart on the lower side of FIG. 4, the thick line indicates the polygon magnification, the broken line indicates the image processing magnification, and the thin line indicates the image magnification during the printing operation (the total magnification of the polygon magnification and the image processing magnification). Even if the magnification is the same, each line is drawn with a slight gap. The same applies to the time charts shown in FIG.
[First Embodiment]
Next, a first embodiment of the present invention will be described. In this embodiment, as in the above-described conventional example, the appropriate range of the image processing variable magnification is -1.0% to + 1.0%, and the image magnification of the surface set in the print job is 0.0%. A case where only the back side is changed to an image magnification of -2.0% will be described.

  In this case, as shown in the table of FIG. 5, the polygon magnification for the surface image is determined to be -1.0%, and the image processing magnification is determined to be + 1.0%. The variable magnification is 0%, and the surface image magnification set in the print job is 0.0%.

  On the other hand, for the back side image, the scaling factor is determined to be -1.0% for polygon scaling and -1.0% for image processing scaling, and the total scaling factor by the combination of both scaling functions is -2. 0.0%, and the image magnification of the back side set in the print job is −2.0%.

  In this print job, printing is performed on a plurality of sheets in the order of front → back → front → back → front → back. However, as shown in the time chart on the lower side of FIG. Scaling is performed at a magnification of -1.0% and an image processing scaling factor of + 1.0%. Even when switching from front to back printing, the polygon scaling factor remains at -1.0%. The magnification switches to -1.0%.

  That is, when switching from front to back printing, only the image scaling ratio is switched and the polygon scaling ratio is the same, so that the switching of the polygon scaling ratio does not occur. For this reason, the speed of the polygon mirror 19 does not change, and the time until the polygon mirror 19 stabilizes at the speed after the change is unnecessary, and the productivity is maintained as it is.

Thus, before changing the image magnification (front side printing) and after the change (back side printing), the image processing magnification rate within the appropriate range is maintained, and the polygon magnification rate is the same value without switching. Since the scaling ratios for processing scaling and polygon scaling are determined, the effect of suppressing deterioration in image quality and productivity is greatly increased.
[Modification 1 of the first embodiment]
In the above embodiment, the scaling factors of the image processing scaling and the polygon scaling are determined so that the polygon scaling ratio becomes the same value for the front side printing and the back side printing. In some cases, the scaling factor cannot be determined so as to be the same value as in printing. For example, when the appropriate range of the image processing magnification is -1.0% to + 1.0%, the front image magnification set in the print job is + 1.0%, and the back image magnification is -2.0%. is there.

  In this case, as shown in the table of FIG. 6, the polygon magnification for the surface image is determined to be 0.0% and the image processing magnification is set to + 1.0%. The magnification is + 1.0%.

  On the other hand, for the back side image, the scaling factor is determined to be -1.0% for polygon scaling and -1.0% for image processing scaling, and the total scaling factor by the combination of both scaling functions is -2. 0.0%, and the image magnification set in the print job is −2.0%.

  In this print job, printing is performed on a plurality of sheets in the order of front → back → front → back → front → back. However, as shown in the bottom time chart of FIG. When switching from front to back printing, the polygon magnification is changed to -1.0% and the image processing magnification is -1.0%. Switch to

  Therefore, when switching from the front side to the back side printing, the scaling factor of the polygon scaling is switched from 0.0% to -1.0%, and the speed of the polygon mirror 19 is changed. However, the difference in switching from front to back printing of the polygon scaling ratio is ± 1.0%, and from only the polygon scaling, the front image magnification is + 1.0% and the back image magnification is -2.0%. The difference before and after the change of the polygon magnification can be reduced as compared with the difference of ± 3.0% in the magnification when switching. For this reason, the time until stabilization after the speed change of the polygon mirror 19 can be shortened, and a decrease in productivity can be suppressed as much as possible.

  FIG. 7 shows image processing at the time of front side printing and at the time of back side printing when the image magnification of the front surface set in the print job is larger than the image magnification of the back side as in the first embodiment and the modification thereof. It is a flowchart which shows each determination process of a variable magnification and a polygon variable magnification. This process is executed by the CPU 101 of the control unit 100 in the image forming apparatus 1 operating according to an operation program recorded on a recording medium such as the ROM 102. The same applies to the flowcharts in FIG.

  In step S01, the upper limit value of the appropriate range of the image processing variable magnification is A1, and the lower limit value is A2, and in step S02, B = image magnification X1 on the front surface—image magnification X2 on the back surface is obtained.

  Next, in step S03, it is determined whether B ≦ (A1-A2). If B ≦ (A1−A2) (YES in step S03), the process proceeds to step S04, and Y1 = X1− (B × (A1 ÷ (A1−A2))) is obtained.

  Next, in step S05, the front surface polygon scaling ratio Y11 = Y1, the back surface polygon scaling ratio Y12 = Y1, the front surface image processing scaling ratio Y21 = X1-Y11, and the back surface image processing scaling ratio Y22 = X2-Y12 are determined.

If B ≦ (A1−A2) is not satisfied in step S03 (NO in step S03), the process proceeds to step S06 as a determination method when the polygon magnification cannot be fixed (same) on both sides, and the surface polygon magnification Y11 = X1-A1, back side polygon magnification Y12 = X2-A2, front side image processing magnification Y21 = X1-Y11, and back side image processing magnification Y22 = X2-Y12.
[Modification 2 of the first embodiment]
Next, a case where the back side image magnification set in the print job is larger than the front side image magnification will be described. In this case, the image processing magnification ratio and polygon magnification ratio at the time of front side printing and back side printing are determined by the determination process shown in the flowchart of FIG.

  In step S11, the upper limit value of the appropriate range of the image processing variable magnification is A1, and the lower limit value is A2. In step S12, B = image magnification X2 on the back surface—image magnification X1 on the front surface is obtained.

  Next, in step S13, it is determined whether B ≦ (A1-A2). If B ≦ (A1−A2) (YES in step S13), the process proceeds to step S14, and Y1 = X2− (B × (A1 ÷ (A1−A2))) is obtained.

  Next, in step S15, the front surface polygon scaling ratio Y11 = Y1, the back surface polygon scaling ratio Y12 = Y1, the front surface image processing scaling ratio Y21 = X1-Y11, and the back surface image processing scaling ratio Y22 = X2-Y12 are determined.

  If B ≦ (A1−A2) is not satisfied in step S13 (NO in step S13), the process proceeds to step S16 as a determination method in the case where the magnification ratio of polygon scaling cannot be fixed (same) on the front and back sides. The magnification Y11 = X1-A2, the back side polygon magnification Y12 = X2-A1, the front side image processing magnification Y21 = X1-Y11, and the back side image processing magnification Y22 = X2-Y12.

  For example, the appropriate range A2 to A1 of the image processing variable magnification is −1.0% to + 1.0%, the front image magnification X1 set in the print job is 0%, and the rear image magnification X2 is + 2.0%. This is the case.

  In this case, if B = 2.0% ≦ (A1-A2) = 2.0%, the determination in step S13 is YES, and in step S14, Y1 = X2- (2.0% × 1.0% ÷ (1 0.0%-(-1.0%))) = 2.0% -1.0% = 1.0%.

  As a result, the polygon magnification is + 1.0% for both the front and back surfaces, and the image processing magnification is -1.0% for the front surface and + 1.0% for the back surface.

  On the other hand, the appropriate magnification range A2 to A1 for image processing magnification is -1.0% to + 1.0%, the front image magnification X1 set in the print job is -1.0%, and the rear image magnification. When X2 is + 2.0%, since B = + 3.0%, B> (A1-A2) = 2.0%, and the determination in step S13 is NO.

As a result, in step S16, the polygon magnification ratio is the front surface Y11 = −1.0% − (− 1.0%) = 0.0%, the back surface Y12 = + 2.0% −1.0% = + 1.0%. Thus, the magnification of the image processing is the front surface Y21 = −1.0% −0.0% = − 1.0% and the back surface Y22 = + 2.0% −1.0% = + 1.0%.
[Modification 3 of the first embodiment]
Next, the case where the enlargement-side range is smaller than the reduction-side range in the appropriate range of the image processing variable magnification will be described. In this case, the image processing magnification ratio and polygon magnification ratio at the time of front side printing and back side printing are also determined by the determination process shown in the flowchart of FIG.

  For example, the appropriate range A2 to A1 of the image processing variable magnification is -1.0% to + 0.5%, the front image magnification X1 set in the print job is 0%, and the rear image magnification X2 is + 1.0%. This is the case.

  In this case, when B = 1.0% ≦ (A1-A2) = 1.5%, the determination in step S13 is YES, and in step S14, Y1 = X2− (1.0% × 0.5% ÷ (0 .5%-(-1.0%)) = 1.0% -0.7% = 0.3%.

  As a result, the polygon magnification is + 0.3% for both the front and back surfaces, and the image processing magnification is -0.3% for the front surface and + 0.7% for the back surface.

  On the other hand, the appropriate magnification range A2 to A1 for image processing scaling is -1.0% to + 0.5%, the front side image magnification X1 set in the print job is -1.0%, and the back side image magnification is When X2 is + 1.0%, since B = + 2.0%, B> (A1-A2) = 1.5%, and the determination in step S13 is NO.

As a result, in step S16, the polygon magnification ratio is the front surface Y11 = −1.0% − (− 1.0%) = 0.0%, the back surface Y12 = + 1.0% −0.5% = + 0.5%. Thus, the magnification of the image processing is the front surface Y21 = −1.0% −0.0% = − 1.0% and the back surface Y22 = + 1.0% −0.5% = + 0.5%.
[Second Embodiment]
A second embodiment will be described with reference to the flowchart of FIG. In the embodiment shown in the flowcharts of FIGS. 7 and 8, when the determination of B ≦ (A1-A2) in step S03 and step S13 is NO, the determination method when the polygon magnification cannot be fixed (same) on both sides Then, the process proceeds to step S06 or step S16, and the image processing magnification ratio and the polygon magnification ratio at the time of front side printing and back side printing are determined so as to be within the appropriate range of the image processing magnification ratio.

  However, in the second embodiment, the determination method in the case where the magnification ratio of the polygon magnification cannot be fixed (same) on both sides is different from the processing in step S06 or step S16, and the appropriate range of the image processing magnification is set. By performing the setting exceeding the limit, the polygon magnification is fixed (same) on the front surface and the back surface, so that the polygon magnification is not switched. By setting the image processing variable magnification beyond the appropriate range, the image deterioration becomes larger than usual, but the occurrence of switching the polygon variable magnification is eliminated while minimizing the deterioration.

  In step S21 in FIG. 9, it is determined whether or not the front side image magnification set in the print job is larger than the back side. If larger (YES in step S21), Y1 = X1- (B * (A1 / (A1-A2))) is obtained in step S22. The value of B in this case is the same as the value of B in step S02 in the flowchart of FIG.

  In step S23, the front surface polygon scaling ratio Y11 = Y1, the back surface polygon scaling ratio Y12 = Y1, the front surface image processing scaling ratio Y21 = X1-Y11, and the back surface image processing scaling ratio Y22 = X2-Y12 are determined.

  On the other hand, if the front side image magnification set in the print job is not larger than the back side in step S21 (NO in step S21), Y1 = X2− (B × (A1 ÷ (A1−A2) in step S24. ))) The value of B in this case is the same as the value of B in step S12 in the flowchart of FIG.

  Next, in step S25, the front side polygon scaling ratio Y11 = Y1, the back side polygon scaling ratio Y12 = Y1, the front side image processing scaling ratio Y21 = X1-Y11, and the back side image processing scaling ratio Y22 = X2-Y12 are determined.

  For example, the appropriate range A2 to A1 of the image processing variable magnification is -1.0% to + 1.0%, the front image magnification X1 set in the print job is + 1.0%, and the rear image magnification X2 is -2. In the case of 0.0%, since B = + 3.0%, B> (A1-A2) = 2.0%, and since the determination in step S21 is YES, in step S22, Y1 = X1- (3.0% × 1.0% ÷ (1.0% − (− 1.0%))) = 1.0% −1.5% = − 0.5%.

  In step S23, the polygon magnification ratio is determined to be −0.5% for both the front surface magnification ratio Y11 and the back surface magnification ratio Y12, and the image processing magnification ratio is the front surface magnification ratio Y21 = 1.0% − (− 0. 0.5%) = 1.5%, and the back side magnification Y22 = −2.0% − (− 0.5%) = − 1.5%.

  As a result, when the print job is executed, an operation as shown in FIG. 10 is performed. That is, printing is performed on a plurality of sheets in the order of front → back → front → back → front → back. However, as shown in the time chart on the lower side of FIG. .5%, image processing scaling factor + 1.5%, and even when switching from front to back printing, the polygon scaling factor remains -0.5% and the image processing scaling factor is -1.5. Switch to%.

Therefore, when switching from front to back printing, only the image scaling ratio is switched and the polygon scaling ratio is the same, so the switching of the polygon scaling ratio does not occur. For this reason, the speed of the polygon mirror 19 does not change, the time until the polygon mirror 19 stabilizes at the changed speed is unnecessary, and the productivity is maintained as it is. However, since the image processing scaling factor is set beyond the appropriate range, image degradation will be larger than usual, but it will be possible to eliminate the degradation of productivity due to switching the polygon scaling factor while minimizing the degradation. it can.
[Third Embodiment]
Next, a third embodiment will be described. This embodiment is an embodiment having a mode for switching between the first embodiment and the second embodiment.

  The user can select and set which is prioritized at the time of double-side scaling from the setting screen of FIG. 11 displayed on the display unit 54 of the operation panel unit 50. In the setting screen of FIG. 11, an “image quality priority” button 54 a and a “productivity priority” button 54 b are displayed.

When the “image quality priority” button 54a is pressed, if the polygon magnification cannot be fixed (same) on the front and back surfaces, step S06 in the flowchart in FIG. 7 and step S16 in the flowchart in FIG. 8 in the first embodiment. As described above, when the image processing magnification is determined within an appropriate range, image quality is given priority over productivity. When the “productivity priority” button 54b is pressed, the image processing scaling factor is determined to exceed the appropriate range as shown in the flowchart of FIG. 9 in the second embodiment, and the scaling factor of the polygon scaling factor is determined. By determining the same value for the front surface and the back surface, productivity is given priority over image quality. Note that the setting screen of FIG. 11 indicates that the “image quality priority” button 54 a is selected.
[Fourth Embodiment]
Next, a fourth embodiment will be described.

  In the first embodiment, when the image magnification set in the print job is different between the front surface and the back surface, the polygon magnification ratio and the image processing magnification ratio are set so as not to switch the speed of the polygon mirror 19 between the front and back surfaces. Is determined. However, since the speed switching of the polygon mirror 19 occurs at the start of printing, it is disadvantageous in the case of printing one sheet on both sides. For example, in the example shown in the table of FIG. 5, the polygon magnification is set to −1.0% on both the front and back sides, so that the polygon mirror 19 is set so that the polygon magnification becomes −1.0% at the start of printing. Speed switching occurs.

  As shown in FIG. 12, when printing only one sheet on both sides, the first surface (front surface) is printed, then the reverse path 90 is passed, and then the second surface (back surface) is printed. spread. As a result, the speed of the polygon mirror 19 can be changed during that time. For this reason, the first copy time is delayed by the amount of speed switching of the polygon mirror 19 at the start of printing.

  The fourth embodiment solves this, and the scaling factor is determined according to the flowchart of FIG. Here, the appropriate range A2 to A1 of the image processing variable magnification is −1.0% to + 1.0%, the front image magnification X1 set in the print job is 0.0%, and the rear image magnification X2 is −. 2.0%.

  In FIG. 13, in step S31, an interval (unit: ms) between the Y (yellow) image and the next Y (yellow) image necessary for switching the speed of the polygon mirror 19 is obtained as time T2 (see FIG. 12). The time T2 is the sum of the time T21 from the end of Y-color writing to the end of K-color writing and the time T22 until the rotation of the polygon mirror 19 whose speed is changed is stabilized. In this example, T2 = 1000 ms (Y Time T21 from the end of color writing to the end of K color writing: 800 ms, and time T22: 200 ms until rotation of the polygon mirror 19 is stabilized).

  Next, in step S32, the first Y color-Y color interval (unit: ms) where the magnification change has occurred is obtained as time T1. For example, when printing three or more sheets on both sides, the first interval from the first surface to the second surface is 100 ms, and when printing two sheets on both sides, the first interval from the first surface to the second surface is 950 ms, Sometimes the first interval from the first surface to the second surface is 1400 ms.

  Next, in step S33, it is determined whether T2> T1. If T2> T1 (YES in step S33), the process proceeds to step S34, and the scaling factor is determined by the process shown in the flowchart of FIG. 7 or FIG. 8 in the first embodiment. For example, when duplex printing is performed, T1 = 950 ms, and T1 = 950 ms <T2 = 1000 ms. Therefore, the scaling factor is determined in the processing of the first embodiment.

  If T2> T1 is not satisfied in step S33 (NO in step S33), the process proceeds to step S35, where the image processing magnification within the preferred range is used, and the surface polygon magnification Y11 is determined so as to use the polygon magnification with the difference. In step S36, the rear surface polygon scaling factor Y12 is determined in the same manner.

For example, in the case of single-sided printing, T1 = 1400 ms> T2 = 1000 ms. Therefore, the magnification ratio is 0.0% for both the polygon magnification ratio and the image processing magnification ratio for the front surface, and the polygon magnification ratio-1. 0% and the image processing magnification ratio -1.0%.
[Fifth Embodiment]
Next, a fifth embodiment will be described. In this embodiment, a print job in which an image magnification change occurs during printing is a print job for printing on a recording sheet fed from a plurality of paper feed trays 21. The present invention relates to a process for determining a polygon scaling factor and an image processing scaling factor when one or a plurality of set image scaling factors are different print jobs.

  This process will be described with reference to the flowchart of FIG. Here, it is assumed that one-sided printing is performed by feeding one sheet at a time from the first sheet feeding tray to the second sheet feeding tray and the third sheet feeding tray.

  In step S41, the upper limit value of the appropriate range of the image processing variable magnification is A1 and the lower limit value is A2. In step S42, the maximum image magnification among the image magnifications set for the paper feed tray 21 to be used is Xmax, and the minimum Let Xmin be the image magnification.

  In step S43, B = Xmax−Xmin is obtained, and in step S44, Y1 = Xmax− (B × (A1 ÷ (A1−A2))) is obtained.

  In step S45, the polygon variable magnification is determined to be Y1 common to all the paper feed trays, and the image processing variable magnification is determined to be obtained by subtracting Y1 from the image magnification X set in each paper feed tray 21 (X-Y1). To do.

  For example, the appropriate range A2 to A1 of the image processing variable magnification is set to -1.0% to + 1.0%, and the image magnification values are the image magnification X1 of the first paper feed tray X1: 0.0% and the second paper supply, respectively. When the paper tray image magnification X2: -2.0% and the third paper feed tray image magnification X3: -1.0% are set, Xmax = 0.0%, Xmin = -2. 0% and B = 2.0%.

  Y1 = Xmax− (2.0% × (1.0% ÷ (1.0% − (− 1.0%)))) = 0.0% −1.0% = − 1.0% It becomes.

  Therefore, the polygon variable magnification is -1.0% common to each paper feed tray, and the image processing variable magnification is the first paper feed tray = + 1.0%, the second paper feed tray = -1.0%, and the third paper feed. Paper tray = 0.0%.

As described above, according to this embodiment, even when different image magnifications are set for each of the plurality of paper feed trays 21 or for each of the plurality of paper feed trays 21, the polygon variable magnification is made common and the speed of the polygon mirror 19 is switched. As a result, a decrease in productivity can be prevented.
[Sixth Embodiment]
Next, a sixth embodiment will be described. In this embodiment, a print job in which a change in image magnification occurs during printing is a print job for printing on a recording sheet of a plurality of paper types, and one or more image magnifications are set for each paper type to be used. The present invention relates to a process for determining a polygon scaling factor and an image processing scaling factor for a plurality of different print jobs.

  This process will be described with reference to the flowchart of FIG.

  In step S51, the upper limit value of the appropriate range of the image processing variable magnification is set to A1, and the lower limit value is set to A2. In step S52, the maximum image magnification among the image magnifications set for the paper type to be used is Xmax, and the minimum image is set. Let the magnification be Xmin.

  After obtaining B = Xmax−Xmin in step S53, Y1 = Xmax− (B × (A1 ÷ (A1−A2))) is obtained in step S54.

  In step S55, the polygon magnification is determined to be Y1 common to all paper types, and the image processing magnification is determined to be (X−Y1) obtained by subtracting Y1 from the image magnification X set for each paper type.

  For example, the appropriate range A2 to A1 of the image processing variable magnification is set to -1.0% to + 1.0%, and the image magnification values are the plain paper image magnification X1: 0.0% and the thin paper image magnification X2, respectively. Assuming that -2.0% and thick paper image magnification X3: 0.0% are set, and printing three pages in the order of thick paper, thin paper, and plain paper in single-sided printing, Xmax = 0.0%, Xmin = −2.0%, and B = 2.0%.

  Y1 = Xmax− (2.0% × (1.0% ÷ (1.0% − (− 1.0%)))) = 0.0% −1.0% = − 1.0% It becomes.

  Therefore, the polygon scaling factor is -1.0% common to each paper feed tray, and the image processing scaling factors are plain paper = + 1.0%, thin paper = -1.0%, and thick paper = + 1.0%.

As described above, according to this embodiment, even when different image magnifications are set for each of the plurality of paper types or for each of the plurality of paper types, the polygon magnification is made common so that the speed of the polygon mirror 19 does not change. Thus, a decrease in productivity can be prevented.
[Seventh Embodiment]
Next, a seventh embodiment will be described. This embodiment relates to the operation in the first embodiment when an adjustment pattern (out-print area pattern) needs to be printed outside the print area for the stabilization process during printing.

  The print job is a print job in which double-sided printing is performed at different image magnifications on the front and back sides, and the appropriate range of the image processing variable magnification is -1.0% to + 1.0%, and the front surface set in the print job The image magnification is 0.0%, and only the back surface has an image magnification of -2.0%. Also, stabilization processing is performed when printing is performed with the polygon scaling factor set to -1.0% for both the front and back surfaces, and the image processing scaling factor set to 1.0% for the front surface and -1.0% for the back surface. Shall be performed. The stabilization process is performed by printing a predetermined adjustment pattern, and this adjustment pattern needs to be printed at an image magnification of 0.0%.

  As shown in FIG. 16A, if polygon scaling has not occurred before printing of the adjustment patterns PY, PM, PC, and PK for each color, it is only necessary to wait for a normal sheet passing time Ta, and to perform Y, M Printing of the adjustment patterns PY, PM, PC and PK for each color can be started after each of the images C, K and K. However, as described above, in the state where the polygon scaling ratio is set to -1.0% for both the front and back surfaces and printed, the polygon scaling ratio is set to-before the adjustment patterns PY, PM, PC, and PK are printed. It is necessary to change from 1.0% to 0.0%. For this reason, as shown in FIG. 16B, a time Tb is required until the speed of the changed polygon mirror 19 is stabilized after the printing of the K color is completed, the image interval is widened, and unnecessary driving is performed. Will be generated.

  Therefore, in order to prevent this, in the seventh embodiment, the scaling factor before printing the adjustment pattern (in this example, -1.0%) is continuously used as the polygon scaling factor, and the image processing scaling factor is The image processing magnification is determined so that there is no magnification in total by combining the polygon magnification. Therefore, in this example, the image processing variable magnification is changed to + 1.0% to be 0.0% in total, and the adjustment patterns PY, PM, PC, and PK for each color are printed in this state.

In this way, it is not necessary to switch the speed of the polygon mirror 19 during polygon scaling, and the stabilization process can be performed quickly.
[Eighth Embodiment]
Next, an eighth embodiment will be described.

  As a fifth embodiment, a print job in which a change in image magnification occurs during printing is a print job for printing on a recording sheet fed from a plurality of paper feed trays. The polygon scaling factor and the image processing scaling factor determination process when one or a plurality of set image scaling factors are different print jobs have been described.

  The eighth embodiment relates to determination processing of a polygon scaling factor and an image processing scaling factor when a print job is started in a state where only a part of paper feed trays to be used is determined.

  This process will be described with reference to the flowchart of FIG.

  In step S61, the upper limit value of the appropriate range of the image processing variable magnification is set to A1, and the lower limit value is set to A2. In step S62, the maximum image magnification among the image magnifications set for all the paper feed trays is Xmax, and the minimum image is set. Let the magnification be Xmin.

  In step S63, B = Xmax−Xmin is obtained, and in step S64, Y1 = Xmax− (B × (A1 ÷ (A1−A2))) is obtained.

  In step S65, the polygon magnification is determined to be Y1 common to all paper feed trays, and the image processing magnification is determined to be obtained by subtracting Y1 from the image magnification X set in each paper feed tray (X-Y1). .

  For example, the appropriate range A2 to A1 of the image processing variable magnification is −1.0% to + 1.0%, and the image magnification is the image magnification X1: 0.0% of the first paper feed tray and the second paper supply, respectively. Assume that the paper tray image magnification X2: -2.0%, the third paper feed tray image magnification X3: -1.0%, and the fourth paper feed tray image magnification X4: 0.0% are set. When one sheet is fed from the first sheet feeding tray and one sheet from the third sheet feeding tray in single-sided printing, and a subsequent job exists but the sheet feeding tray is undetermined, Xmax = 0.0 %, Xmin = −2.0%, and B = 2.0%.

  Y1 = Xmax− (2.0% × (1.0% ÷ (1.0% − (− 1.0%)))) = 0.0% −1.0% = − 1.0% It becomes.

  Therefore, the polygon variable magnification is -1.0% common to each paper feed tray, and the image processing variable magnification is the first paper feed tray = + 1.0%, the second paper feed tray = -1.0%, and the third paper feed. Paper tray = 0.0% and fourth paper feed tray = + 1.0%.

As described above, according to this embodiment, even when, for example, the use of the second paper feed tray is confirmed after printing is started, the polygon scaling ratio is not changed in the middle of the print job, thereby preventing a decrease in productivity. Can do.
[Ninth Embodiment]
Next, a ninth embodiment will be described.

  As a sixth embodiment, a print job in which a change in image magnification occurs during printing is a print job for printing on a recording sheet of a plurality of paper types, and the image magnification set for each paper type used is 1 In the above, the determination processing of the polygon scaling factor and the image processing scaling factor in the case of one or a plurality of different print jobs has been described.

  The ninth embodiment relates to determination processing of a polygon scaling factor and an image processing scaling factor when a print job is started in a state where only a part of paper types to be used is determined.

  This process will be described with reference to the flowchart of FIG.

  In step S71, the upper limit value of the appropriate range of the image processing variable magnification is A1, and the lower limit value is A2. In step S72, the maximum image magnification among the image magnifications set for all the paper types is Xmax, and the minimum image magnification is set. Let Xmin.

  In step S73, B = Xmax−Xmin is obtained, and in step S74, Y1 = Xmax− (B × (A1 ÷ (A1−A2))) is obtained.

  In step S75, the polygon magnification is determined to be Y1 common to all paper types, and the image processing magnification is determined to be (X-Y1) obtained by subtracting Y1 from the image magnification X set for each paper type.

  For example, the appropriate range A2 to A1 of the magnification ratio for image processing magnification is set to -1.0% to + 1.0%, and the image magnification values are the image magnification value X1: -1.0% for plain paper and thin paper, respectively. Image magnification value X2: -2.0% and thick paper image magnification value X3: 0.0% are set, and printing is performed on one sheet of plain paper and one sheet of plain paper by single-sided printing. Assuming that the job exists but the paper type to be called is undetermined, Xmax = 0.0%, Xmin = −2.0%, and B = 2.0%.

  Y1 = Xmax− (2.0% × (1.0% ÷ (1.0% − (− 1.0%)))) = 0.0% −1.0% = − 1.0% It becomes.

  Therefore, the polygon scaling factor is -1.0% common to each paper type, and the image processing scaling factors are plain paper = 0.0%, thin paper = -1.0%, and thick paper = + 1.0%.

  As described above, according to this embodiment, even when the use of, for example, thin paper is determined after printing is started, the polygon magnification is not changed in the middle of the print job, thereby preventing a decrease in productivity.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Image forming part 20 Paper feed part 21 Paper feed tray 17 Image processing part 18 Polygon motor 19 Polygon mirror 50 Operation panel part 54 Display part 100 Control part 101 CPU
102 ROM
103 RAM
110 Fixed storage device S Paper (recording sheet)

Claims (12)

A first scaling unit capable of scaling an image by image processing and having an appropriate range of settable scaling factors;
A second scaling means capable of scaling the image by adjusting the speed of the polygon mirror;
Each of the first scaling unit and the second scaling unit is configured to obtain a predetermined image magnification by combining the scaling factor of the first scaling unit and the scaling factor of the second scaling unit. A determining means for determining a scaling factor;
With
The determination unit is a print job in which a change in image magnification occurs during printing, and at least one of the image magnifications before or after the change of the image magnification is the appropriate magnification of the first magnification unit When a print job exceeding the range is input, the first scaling unit and the second scaling unit for the first image before the change of the image magnification and the second image after the change, respectively. An image forming apparatus, wherein a scaling factor is determined in advance before printing the first image and the second image.   The determining unit is configured so that the magnification ratio of the first scaling unit is within the appropriate range before and after the change of the image magnification, and the variation amount of the scaling factor of the second scaling unit is small. The image forming apparatus according to claim 1, wherein a scaling factor of each of the first scaling unit and the second scaling unit is determined.   The determining unit is configured to change each of the first scaling unit and the second scaling unit so that the scaling factor of the second scaling unit is the same before and after the change of the image magnification. The image forming apparatus according to claim 2, wherein the magnification is determined.   The image forming apparatus according to claim 1, wherein the determining unit determines a set value that deviates from the appropriate range as a scaling factor of the first scaling unit. Non-image area interval T1 when the image magnification is changed, and non-image area required when changing the magnification of the second scaling unit before the image magnification is changed to the magnification after the change of the image magnification A calculation means for calculating the interval T2 of
The calculating means calculates the intervals T1 and T2 at one or more locations, and the determining means is based on the comparison between the calculated intervals T1 and T2, and the first scaling means and the second changing means. The image forming apparatus according to claim 1, wherein each magnification of the magnification unit is determined.   The image forming apparatus according to claim 1, wherein the print job in which a change in image magnification occurs during printing is a print job in which the image magnification is different between the front surface and the back surface in the case of duplex printing.   The print job in which an image magnification change occurs during printing is a print job for printing on a recording sheet fed from a plurality of paper feed trays, and the image magnification set for each paper feed tray to be used is The image forming apparatus according to claim 1, wherein one or a plurality of different print jobs are used.   The print job in which a change in image magnification occurs during printing is a print job for printing on a recording sheet of a plurality of paper types, and a print in which the image magnification set for each paper type used differs by one or more. The image forming apparatus according to claim 1, wherein the image forming apparatus is a job.   When it becomes necessary to print a pattern outside the print area without scaling for image stabilization processing after the change of the image magnification, the determining means uses the print area as the scaling ratio of the second scaling means. The first magnification is determined so that the magnification before the printing of the outer pattern is continuously used, and the magnification of the first scaling unit and the scaling of the second scaling unit are combined to eliminate the scaling. The image forming apparatus according to claim 1, wherein a scaling ratio of the scaling unit is determined.   When the print job is started in a state where only a part of the used paper feed trays is determined, the first and second zooming means including the unused paper feed trays are included. The image forming apparatus according to claim 7, wherein each of the magnifications is determined in advance before printing the first image and the second image.   When the print job is started in a state where only some of the used paper types are fixed, each of the first scaling unit and the second scaling unit includes the unused paper types. The image forming apparatus according to claim 8, wherein the zoom ratio is determined in advance before printing the first image and the second image. A first scaling unit capable of scaling an image by image processing and having an appropriate range of settable scaling factors; a second scaling unit capable of scaling the image by adjusting the speed of a polygon mirror; In the computer of the image forming apparatus having
Each of the first scaling unit and the second scaling unit is configured to obtain a predetermined image magnification by combining the scaling factor of the first scaling unit and the scaling factor of the second scaling unit. The step of determining the scaling factor is executed,
A print job in which a change in image magnification occurs during printing, and at least one of the image magnifications before or after the change of the image magnification exceeds the appropriate range of the magnification ratio of the first scaling unit Is input, the respective scaling factors of the first scaling unit and the second scaling unit with respect to the first image before the change of the image magnification and the second image after the change, respectively, A program for executing a predetermined process before printing the first image and the second image.

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