JP2020184011A - Image forming apparatus, image forming method, and image forming program - Google Patents

Abstract

To provide a technology to reduce output of a sheet on which noise is formed.SOLUTION: An image forming apparatus comprises: a periodic component that is a component driving in a certain period; a noise specification unit that specifies the position of noise that is periodically formed due to the malfunction of the periodic component; a noise avoiding method determination unit that determines a noise avoiding method for preventing a document image from being formed at the position of noise specified by the noise specification unit, from a plurality of methods provided in advance, based on the position of the noise; and a printing execution unit that prints the document image on the sheet with the method determined by the noise avoiding method determination unit.SELECTED DRAWING: Figure 4

Description

The present invention relates to an image forming apparatus, an image forming method, and an image forming program.

In recent years, the digitization of information has tended to be promoted, and image processing devices used for outputting digitized information have become indispensable devices. Such an image processing device can be used as a printer, a scanner, a facsimile, or a copier by providing a reading function for reading a sheet, an image forming function for forming an image on the sheet, a communication function, and the like.

In an image processing apparatus, when a defect occurs in a component that rotates at a constant cycle such as an intermediate transfer belt, an unintended defective image (hereinafter referred to as noise) such as a streak or a point may be periodically formed.

Further, a technique for quickly and accurately identifying the causative component when a periodic abnormality occurs in the output image is disclosed (Patent Document 1).

If a defect is found in the diagnosis of a part that rotates in a cycle such as an intermediate transfer belt, either do not use the image forming device until repair or parts replacement, or allow periodic noise output. Must continue to be used. In addition, the serviceman may not be able to take immediate action due to lack of parts inventory.

An object of the present invention is to provide a technique for reducing the output of a sheet in which periodic noise is formed.

In order to solve the above problems, the image forming apparatus of the present invention includes a periodic component that is a component that is driven at a constant cycle, and a noise specifying unit that specifies the position of noise that is periodically formed due to a defect in the periodic component. , A noise avoidance method determination unit that determines a noise avoidance method for preventing the original image from being formed at the noise position specified by the noise identification unit based on the noise position from a plurality of predetermined noise avoidance methods and a noise avoidance method. It has a print execution unit for printing a document image on a sheet by a method determined by the determination unit.

According to the present invention, it is possible to reduce the output of a sheet in which periodic noise is formed.

It is a schematic diagram which shows the outline of the image forming apparatus. It is a block diagram which shows the hardware composition which plays a control of an image forming apparatus. It is a figure which illustrates the functional block of the image forming apparatus of embodiment. It is a flowchart which illustrates the operation of the image forming apparatus of embodiment. It is a figure which illustrates periodic noise. It is a figure explaining the method of specifying the noise position of an embodiment. It is a figure explaining the method of specifying the noise position of an embodiment. It is a figure which illustrated the setting screen of an embodiment. It is a figure which illustrates the noise avoidance method of embodiment. It is a figure which illustrates the noise avoidance method of embodiment. It is a figure which illustrates the noise avoidance method of embodiment. It is a figure which illustrates the noise avoidance method of embodiment. It is a figure explaining the embodiment example which reduces the influence of the defective output of an embodiment. It is a figure explaining the embodiment example which reduces the influence of the defective output of an embodiment.

Hereinafter, the image forming apparatus, the image forming method, and the image forming program according to the embodiment will be described with reference to the drawings. Further, in the following description, a paper medium (referred to as paper if necessary) is illustrated as a sheet, but for example, a sheet made of plastic, cloth, metal, or the like can also be applied.

<Overall configuration of image forming device>
FIG. 1 is a diagram showing an outline of an image forming apparatus. The image forming apparatus 1 includes an image forming unit 100, a post-processing apparatus 400 including a sheet loading apparatus, and an image reading apparatus 500.

The image forming unit 100 is an indirect transfer type tandem type image forming unit capable of forming a color image. The image forming unit 100 has an image forming unit 110 in which the image forming stations 111 of four colors are arranged, and an optical writing unit 113 provided adjacent to the lower part of the image forming unit 110. The image forming unit 100 conveys the paper picked up by the paper feeding unit 120 having a plurality of paper feeding trays 121 provided below the image forming unit 110 and the paper feeding unit 120 to the secondary transfer unit 140 and the fixing unit 150. It has a paper feed transport path 130 to be used. The image forming unit 100 provides a paper ejection path 160 for transporting the paper on which the image is fixed to the post-processing device 400, and a double-sided transport path 170 for inverting the paper on which the image is formed on one side and forming an image on the other side. Have.

The image-creating station 111 of the image-creating unit 110 contains a photoconductor drum for each color of YMCK, and a charging unit, a developing unit, a primary transfer unit, a cleaning unit, and a static elimination unit arranged along the outer circumference of the photoconductor drum. Have. The image forming unit 110 has an intermediate transfer belt 112 that intermediately transfers the image formed on the photoconductor drum by the primary transfer unit. The optical writing unit 113 writes an image on the photoconductor drum for each color. The optical writing unit 113 is arranged below the image forming station 111, and the intermediate transfer belt 112 is an endless belt arranged above the image forming station 111. The intermediate transfer belt 112 is rotatably supported by a plurality of support rollers. One of the support rollers 114 faces the secondary transfer roller 115 at the secondary transfer unit 140 via the intermediate transfer belt 112, so that the image on the intermediate transfer belt 112 can be secondarily transferred to paper. .. As such an image forming process, a known one may be adopted.

The paper feed unit 120 has one or more paper feed trays 121, and in the example of FIG. 1, two paper feed trays 121 are provided. Each of the paper feed trays 121 has a pickup roller 122 and a paper feed transport roller 123, picks up the paper placed on the tray, and feeds it upward along the paper feed transport path 130. When a plurality of paper feed trays 121 are provided in this way, sheets of different sizes and materials may be placed on each of them, or sheets of the same size may be placed in different vertical and horizontal directions. May be good. Alternatively, the sheets of the same size are placed in the same orientation, and when the paper feeding in one paper feed tray 121 is completed, the paper feeding in the other paper feed tray 121 is started. May be good.

The image of the paper sent out from the paper feeding unit 120 is transferred by the secondary transfer unit 140 and sent to the fixing unit 150. The fixing unit 150 includes a fixing roller and a pressure roller, and in the process of passing the paper through the nip between the two, heating and pressure are performed to fix the toner to the paper.

A paper ejection path 160 and a double-sided transport path 170 are provided downstream of the fixing portion 150, and both are branched in two directions by a branch claw 161 and are transported to the aftertreatment device 400 side or to the double-sided transport path 170. The transport path is selected depending on the case of transport. A branch transfer roller 162 is provided in the immediate vicinity of the branch claw 161 on the upstream side in the paper transfer direction to apply a transfer force to the paper.

The post-processing device 400 performs a predetermined process (for example, binding process) on the image-formed paper conveyed from the image forming unit 100, and loads the image-formed paper on the output tray 404 located at the most downstream position.

The image reading device 500 lightly scans the document set on the contact glass to read the image on the document surface. A known configuration and function of the image reading device 500 itself may be adopted.

The image forming unit 100 configured as described above generates image data to be used for writing based on the original data read from the image reading device 500 or the print data transferred from an external personal computer or the like. Then, the optical writing unit 113 writes light to each photoconductor drum based on the image data, and the images formed for each color at each image forming station 111 are sequentially transferred to the intermediate transfer belt 112. As a result, a color image in which four color images are superimposed on the intermediate transfer belt 112 is formed. On the other hand, paper is fed from the paper feed tray 121 according to the image formation. The paper temporarily stops at the position of the resist roller 191 immediately before the secondary transfer unit 140, is fed out at the same timing as the image tip on the intermediate transfer belt 112, is secondarily transferred by the secondary transfer unit 140, and is fixed. It is sent to 150.

The paper on which the image is fixed by the fixing unit 150 is conveyed to the output path 160 side by the switching operation of the branch claw 161 in the case of single-sided printing and after double-sided printing in double-sided printing, and in the case of double-sided printing. It is transported to the double-sided transport path 170 side. The paper conveyed to the double-sided transfer path 170 is inverted and then fed again to the secondary transfer unit 140 to form an image on the other side surface and returned to the paper ejection path 160. The paper conveyed to the output path 160 is conveyed to the post-processing device 400, and is subjected to a predetermined process such as a binding process by the post-processing device 400, or is discharged to the output tray 204 without any process.

In addition to the above configuration, in the present embodiment, an imaging unit 180a for capturing an image formed on the intermediate transfer belt 112 is provided, and an imaging unit 180b for capturing an image formed on the paper is provided. .. The images captured by the imaging unit 180a and the imaging unit 180b are output to the controller 210 described with reference to FIG.

FIG. 2 is a diagram showing an example of a hardware configuration responsible for controlling the image forming apparatus 1. As shown in FIG. 2, the image forming apparatus 1 includes a controller 210, a short-range communication circuit 220, an engine control unit 230, an operation panel 240, and a network I / F (Interface) 250.

The controller 210 includes a CPU 201 which is a main part of a computer, a system memory (MEM-P) 202, a north bridge (NB) 203, a south bridge (SB) 204, an ASIC (Application Specific Integrated Circuit) 206, and a local memory which is a storage unit. It has (MEM-C) 207, HDD (Hard Disk Drive) controller 208, and HD209 as a storage unit, and has a configuration in which NB203 and ASIC206 are connected by an AGP (Accelerated Graphics Port) bus 221. ..

The CPU 201 is a control unit that controls the entire image forming apparatus 1. The NB 203 is a bridge for connecting the CPU 201, the MEM-P202, the SB204, and the AGP bus 221. The NB 203 includes a memory controller that controls reading and writing to the MEM-P202, a PCI (Peripheral Component Interconnect) master, and an AGP target. Has.

The MEM-P202 includes a ROM 202a that is a memory for storing programs and data that realizes each function of the controller 210, and a RAM 202b that is used as a memory for developing programs and data and a memory for drawing at the time of memory printing. The program stored in the RAM 202b is configured to be provided by recording a file in an installable format or an executable format on a computer-readable recording medium such as a CD-ROM, CD-R, or DVD. You may.

The SB204 is a bridge for connecting the NB203 to the PCI device and peripheral devices. The ASIC 206 is an IC (Integrated Circuit) for image processing applications that has hardware elements for image processing, and has a role of a bridge that connects the AGP bus 221 and the PCI bus 222, the HDD controller 208, and the MEM-C207, respectively. The ASIC 206 is a PCI target and an AGP master, an arbiter (ARB) that forms the core of the ASIC 206, a memory controller that controls the MEM-C907, and a plurality of DMACs (Direct Memory Access Controllers) that rotate image data by hardware logic. , And a PCI unit that transfers data between the scanner unit 231 and the printer unit 232 via the PCI bus 222. Here, the scanner unit 231 is a substrate that controls the operation of the image reading device 500, and the printer unit 232 is a substrate that controls the operation of the image forming unit 100. A USB (Universal Serial Bus) interface or an IEEE 1394 (Institute of Electrical and Electronics Engineers 1394) interface may be connected to the ASIC 206.

The MEM-C207 is a local memory used as a copy image buffer and a code buffer. The HD209 is a storage for accumulating image data, accumulating font data used at the time of printing, and accumulating forms. The HD209 controls reading or writing of data to the HD209 according to the control of the CPU 201. The AGP bus 221 is a bus interface for a graphics accelerator card proposed to speed up graphics processing, and the graphics accelerator card can be speeded up by directly accessing the MEM-P202 with high throughput. ..

Further, the short-range communication circuit 220 is provided with a communication circuit 220a such as NFC and Bluetooth (registered trademark), and realizes data communication with an IC card possessed by the user. When the user holds the IC card near the communication circuit 220a, the short-range communication circuit 220 reads various data recorded on the IC card.

The engine control unit 230 is composed of a scanner unit 231 and a printer unit 232. Further, the operation panel 240 displays the current setting value, the selection screen, and the like, and displays the panel display unit 240a such as a touch panel that accepts the input from the user, and the setting value of the condition related to image formation such as the density setting condition. It is provided with an operation panel 240b including a numeric keypad for receiving and a start key for receiving a copy start instruction. The controller 210 controls the entire image forming apparatus 1, and controls, for example, drawing, communication, input from the operation panel 240, and the like. The scanner unit 231 or the printer unit 232 includes an image processing portion such as error diffusion and gamma conversion.

The image forming apparatus 1 can sequentially switch and select the document box function (= scanner function), the copy function, the printer function, and the facsimile function by the application switching key on the operation panel 240.

Further, the network I / F 250 is an interface for performing data communication using the communication network 190. The short-range communication circuit 220 and the network I / F 250 are electrically connected to the ASIC 206 via the PCI bus 222.

<Aspect of this embodiment>
Next, each function provided in the image forming apparatus 1 of the present embodiment will be described with reference to FIG. The image forming apparatus 1 includes a defective component identification unit 310, a noise identification unit 320, a noise avoidance method determination unit 330, a presentation unit 340, a priority setting unit 350, and a print execution unit 360. Each of these functional units is realized by the controller 210 collaborating with various hardware described above.

The defective part identification unit 310 periodically identifies a periodic component that causes image deterioration by a conventional defect diagnosis method. Here, the periodic component means a component that is driven at a constant cycle, such as an intermediate transfer belt, a roller, and a photoconductor drum of an image forming apparatus.

The noise specifying unit 320 identifies the position of an unintended defective image (referred to as noise) such as a streak or a point, which is periodically generated by the operation of a periodic component having a defect. In the present embodiment, the imaging unit 180a and the imaging unit 180b are operated to specify the noise formation position on the intermediate transfer belt 112 or the noise position on the sheet based on the images captured by these. Although unintended defective images formed on the intermediate transfer belt 112 and the sheet are regarded as noise here, deteriorated parts such as scratches on the intermediate transfer belt 112 and deposits on the belt may be treated as noise. That is, when an unintended object is periodically imaged by the image pickup unit 180a or the image pickup unit 180b, the noise identification unit 320 treats this as noise.

The presentation unit 340 presents to the user a list of methods for forming an image on the sheet (hereinafter, referred to as "noise avoidance method") so as not to print the noise generated periodically, and obtains the priority from the user. Display the screen image to do. The screen image displayed here and the specific contents of the noise avoidance method will be described later, but in the present embodiment, a plurality of noise avoidance methods are provided in advance, and the presentation unit 340 displays a list of these.

The priority setting unit 350 acquires the order of the priority determined by the user via the presentation unit 340, and stores this in, for example, HD209.

The noise avoidance method determination unit 330 determines one of a plurality of possible noise avoidance methods based on the identified noise position. The noise avoidance method determination unit 330 sequentially evaluates whether or not the noise avoidance method can be implemented in the order of default or the priority set by the user, and when a feasible noise avoidance method is reached, the noise avoidance method is concerned. The print execution unit 360 in the subsequent stage is instructed to carry out the method.

The print execution unit 360 forms an image on the sheet by the noise avoidance method determined by the noise avoidance method determination unit 330.

FIG. 4 is a flowchart showing an operation example of the image forming apparatus 1.

The defective component identification unit 310 detects a defective component by a conventional automatic defect diagnosis or a serviceman's diagnosis (S401). As an automatic defect diagnosis, for example, an image formed on the intermediate transfer belt 112 or the sheet is imaged by the imaging unit 180a or the imaging unit 180b, and the captured image and the original image (the image of the original read by the image reading device 500, Alternatively, it is compared with the print image in the print data transferred from the external personal computer), and the defect is found based on the position, size, shape, etc. of the local region (that is, the noise forming region) on the image, which is the difference. Identify the part that is occurring. The defective part may be identified by the driving sound of each part.

The defective component identification unit 310 determines whether the defective component is a periodic component (S402).

The determination of whether or not the periodic component is defective will be described with reference to FIG. When a defect occurs in a periodic component, periodic noise appears in the image output to the sheet (hereinafter referred to as sheet P) (it may not appear depending on the defective part).

FIG. 5A illustrates that a streak-like noise E1 having a period length L1 and a length L2 is formed on the sheet P. The interval at which noise is generated and corresponding to the noise generation interval in the transport direction is referred to as a "cycle length" here. Further, FIG. 5B shows that the point noise E2 is formed at the position L4 from the end in the direction orthogonal to the transport direction with a period length L3. FIG. 5C shows that a relatively large point noise E3 is formed at a position L6 from the other end of the sheet P with a period length L5.

As shown in each drawing of FIG. 5, the defective component identification unit 310 is determined by determining whether unintended streaks or points of the same position or the same type occur at equal intervals (periodic) in the transport direction of the sheet P. Determines if a defect has occurred in the periodic component. In this determination, as shown in FIG. 5C, it is assumed that noise is generated between the sheets P and the sheets P. Therefore, the defective part identification unit 310 may be used between the sheets as needed. Is also interpolated to determine whether noise is generated at equal intervals. In the case of a defective output due to a periodic component, the defective component identification unit 310 holds a time interval (cycle) in which noise is generated based on the obtained cycle length in the storage unit.

Here, when the defective component is not a periodic component (S402: No), the sheet P after image formation is discharged as it is (S430) regardless of whether or not noise is formed on the sheet P.

When the defective part is a periodic part (S402: Yes), the noise specifying unit 320 specifies the position where the periodic noise is generated (S403).

A method of specifying the noise generation position will be described with reference to FIGS. 6 and 7. FIG. 6 shows a case where streak-like noise E1 is generated, and FIG. 7 shows a case where point-like noises E2 and E3 are generated. In this embodiment, a reference position for specifying the noise generation position is provided in advance. When specifying the position of noise on the intermediate transfer belt 112, in the present embodiment, any position on the belt as a base point is used as a reference position. When specifying the position of noise on the sheet P, the corner portion of the sheet P is used as a reference position (see FIGS. 6 and 7). The selection of the reference position is not limited to these.

The noise position is represented by two-dimensional coordinates indicated by the sheet transport direction (x-axis component) from the reference position of each component and the direction orthogonal to the sheet transport direction (y-axis component). The noise specifying unit 320 first identifies the position closest to the reference position in the sheet transport direction, that is, (x1, y1) in FIG. 6 and (x3, y3) in FIG. 7 as the position where noise is generated. Then, the noise specifying unit 320 specifies a rectangular region including the noise as a noise generation position. In the streak noise E1 of FIG. 6, the broken line range surrounded by (x1, y1) to (x2, y2) is the noise generation position, and in the point noises E2 and E3 of FIG. 7, (x3, y3) to ( The broken line range surrounded by x4, y4) is the noise generation position.

Returning to the description of the flowchart of FIG. The noise avoidance method determination unit 330 acquires a priority (priority) for evaluating which method is feasible among some noise avoidance methods provided in advance (S404). The noise avoidance method determination unit 330 may acquire the default priority stored in the HD 209 in advance, or may acquire the priority set by the user via the presentation unit 340.

Here, FIG. 8 shows an example of the priority setting screen displayed by the presentation unit 340. On the setting screen shown in FIG. 8, a list of periodic noise avoidance methods is displayed, and for each noise avoidance method, there is a field for inputting whether or not to implement the avoidance method (“implementation” column in the figure) and a field for performing the noise avoidance method. A field for inputting the priority of the case (“priority” field in the figure) is arranged. In this embodiment, the following workarounds are registered in advance.
・ Output where noise is generated according to the space between papers ・ Output by changing the paper orientation ・ Output by changing the main scanning position ・ Output by changing the paper size In addition to these, it is also possible to set to output as it is .. FIG. 8 illustrates a setting for executing other than “output by changing the main scanning position”. Further, FIG. 8 gives the highest priority to evaluate whether or not it is possible to "output the noise generation portion according to the space between the papers", and then "output by changing the paper size", "output by changing the paper orientation", and "output". The setting in which the feasibility evaluation is performed is illustrated in the order of "output as is".

The priority setting unit 350 excludes the noise avoidance method that cannot be implemented by the user, sorts in the order of the priority input by the user, and writes the identification information of the noise avoidance method in a predetermined setting file. Then, the noise avoidance method determination unit 330 reads the setting file in S404 and evaluates in the order of the setting files. However, in the flowchart of FIG. 4, each step after S410 is set by default as "output at the location where noise is generated according to the space between papers", "output by changing the paper orientation", and so on. It is assumed that the evaluation is performed in the order of "output by changing the main scanning position" and "output by changing the paper size".

<Output the noise generation location according to the space between the papers>
The noise avoidance method determining unit 330 compares the length of the interval at which noise is generated (that is, the periodic length) with the length of the sheet P in the transport direction (hereinafter, referred to as paper length) (S401). When the period length is longer than the paper length (S401: Yes), the noise avoidance method determining unit 330 determines the noise avoidance method so as to "output the noise generation portion in time with the paper space". Then, the print execution unit 360 controls the image formation and the sheet transfer on the intermediate transfer belt 112 so that the noise forming portion is between the sheets (S420).

S420 will be described with reference to FIG. In the following description, it is assumed that the point noises E2 and E3 are generated as the periodic noise, but the same applies to the streak noise E1. Further, the “printable range in the main scanning direction” shown in FIG. 9 indicates a range in which the image forming unit 110 can image in the main scanning direction, that is, in the direction orthogonal to the sheet transport direction, and the belt width of the intermediate transfer belt 112 Is the upper limit.

If the output is made as it is without being aware of the noise generation location, it is printed as it is on the sheet P as shown in the upper part of FIG. 9, and a defective output appears. In this case, since the period length is longer than the paper length, it is possible to avoid the noise output by forming the original image between the noise and transferring it to the sheet P (Fig.). See the bottom of 9). The print execution unit 360 controls the operation timings of the optical writing unit 113 and the image forming unit 110 so as to form an image on the intermediate transfer belt 112 between noise, and is formed on the intermediate transfer belt 112. The rotation drive timing of the resist roller 191 is controlled so that the image is correctly formed on the sheet P. As a result, noise is not formed on the surface of the sheet P.

<Output by changing the paper orientation>
Returning to the description of the flowchart of FIG. When the paper length is longer than the cycle length in S410 (S410: No), the noise avoidance method determining unit 330 then compares the cycle length and the paper width (the length of the sheet P in the direction orthogonal to the transport direction). (S411). When the cycle length is longer than the paper width (S411: Yes), the noise avoidance method determining unit 330 determines the noise avoidance method so as to "output by changing the paper orientation". The print execution unit 360 changes the orientation of the sheet P to form an image so that the noise generation portion is output in line with the space between the papers (S421).

FIG. 10 is a diagram illustrating the operation of S421. The print execution unit 360 operates the scanner unit 231 or the printer unit 232 or the ASIC 206 to newly create an image obtained by rotating the original image by 90 degrees. Then, the print execution unit 360 controls the operation timings of the optical writing unit 113 and the image forming unit 110 so that an image rotated 90 degrees between noises is formed on the intermediate transfer belt 112. On the other hand, the print execution unit 360 operates the paper feed unit 120 so as to feed paper from the paper feed tray 121 on which the horizontally oriented sheets having different orientations by 90 degrees are loaded. Then, the print execution unit 360 controls the rotation drive timing of the resist roller 191 so that the image formed on the intermediate transfer belt 112 is correctly formed on the sheet P. By this operation control, image formation can be performed without printing noise (see the lower part of FIG. 10).

<Output by changing the main scanning position>
Returning to the description of the flowchart of FIG. When the paper width is longer than the noise cycle length in S411 (S411: No), the noise avoidance method determining unit 330 determines whether the noise can be avoided by shifting the sheet P in the main scanning direction. (S412).

The determination of S412 will be described with reference to FIG. 11 (A). In other words, the determination of S412 calculates (main scanning position of noise-end A of printable range in main scanning direction) and (end B of printable range in main scanning direction-main scanning position of noise), respectively. However, it is determined whether or not the larger value is longer than the paper width (short side) of the sheet. As shown in FIG. 11A, (the main scanning position of noise-the end A of the printable range in the main scanning direction) is the length La from the end A to the noise position, and is (the main scanning direction). The end B-noise main scanning position of the printable range) is the length Lb from the other end B to the noise position. In S412, it is determined whether La or Lb can be secured to the extent that the sheet P can be accommodated.

When S412 is an affirmative determination (S412: Yes), the print execution unit 360 outputs the output by shifting the position in the main scanning direction so as to avoid noise (S422).

S422 will be described with reference to FIGS. 11 (C) and 11 (B). The print execution unit 360 first compares the lengths of La and Lb. When (La ≦ Lb) is established, the print execution unit 360 forms an image on the intermediate transfer belt 112 so as to be closer to the end portion B, and conveys the sheet P so as to be closer to the end portion B side. Control is performed (see FIG. 11B). On the other hand, when (La> Lb) is established, the print execution unit 360 forms an image on the intermediate transfer belt 112 so as to be closer to the end A side, and the sheet P is closer to the end A side. (See FIG. 11 (C)).

By forming the image by shifting the position in the main scanning direction in this way, the image can be formed without printing noise.

<Output by changing the paper size>
Returning to the description of the flowchart of FIG. When S412 is a negative determination (S412: No), the noise avoidance method determining unit 330 determines whether or not noise can be avoided by reducing and changing the size of the original image and the size of the sheet (S413). ). In S413, for example, in the case of a document image for A4 size, the noise avoidance method determining unit 330 determines whether noise can be avoided by changing the size to B5 or A5, which is smaller than A4 size.

S413 will be described with reference to FIG. First, the noise avoidance method determining unit 330 derives the largest value among the values of the cycle lengths Lc, La, and Lb compared with each other. In the example of FIG. 12, Lb has the largest value. Next, the noise avoidance method determining unit 330 selects the largest sheet among the sheets that can be fed, which has a side smaller than Lb. Here, if the sheet cannot be selected because the corresponding sheet cannot be supplied (S413: No), the process proceeds to S430.

On the other hand, if selection is possible (S413: Yes), the print execution unit 360 generates an image reduced from the size requested for printing to the size after selection, and a region in which noise can be avoided (FIG. 12). In the example of, various units are controlled so as to print through the sheet in the area of width Lb).

By doing so, although it is not possible to satisfy the sheet size requested for printing, it is possible to form an image without printing noise.

Returning to the description of the flowchart of FIG. In S413, when noise cannot be avoided by changing the size (S413: No), the print execution unit 360 forms an image (S430) if it can output even if a defect of a component occurs. The presentation unit 340 may indicate to the user that a defect has occurred in the component.

<Examples of other aspects>
In addition to the above, the influence of noise may be minimized by switching the processing according to the content of the original image. Two types of methods will be described with reference to FIGS. 13 and 14. The following two types of methods may be performed by the print execution unit 360 when neither of the noise avoidance methods can be implemented.

FIG. 13 is a diagram for explaining a method of applying noise to a blank area where an image is not formed. When the original image shown in the upper part of FIG. 13 is printed as it is in a state where periodic noise is formed as shown in the upper part of FIG. 13, noise hits the characters drawn in the original image and the readability is good. No image will be formed. The print execution unit 360 rotates the original image by 180 degrees so that noise is not applied to the image forming region (see the lower part of FIG. 13).

When printing a document having a large number of blank areas, the readability of the output result document can be maintained by preventing noise from appearing in the printed area (image forming area). In the present embodiment, among the rectangular areas that are not printed at all, those having a specified size or larger are treated as blank areas. Then, the noise avoidance method determination unit 330 or the print execution unit 360 determines whether or not there is such a blank area. When there is a blank area, the print execution unit 360 derives the rotation angle of the original image so as to apply noise to the blank area based on the position of the blank area and the position of the noise. Then, the print execution unit 360 rotates the original image at the derived angle, and switches the paper feed tray 121 so as to switch the vertical and horizontal lengths of the sheet as necessary.

FIG. 14 is a diagram illustrating a method of applying noise to a region where a high-density color is formed (a region where a dark color is formed). As shown in the upper part of FIG. 14, when the original image has an area solidly painted with a dark color such as black, dark blue, or dark green, the print execution unit 360 prints so as to apply noise to the dark area. Shift the position. As a result, the noise can be made inconspicuous. In the present embodiment, when the transfer amount (output density) of the toner is higher than the specified value, it is treated as forming a high density color (dark color).

As described above, according to the embodiment of each of the above-described embodiments, it is possible to provide a technique for printing on a sheet so as to avoid noise output points. As a result, defective output can be reduced.

1: Image forming apparatus 100: Image forming unit 110: Image forming unit 111: Image forming station 112: Intermediate transfer belt 113: Optical writing unit 120: Paper feeding unit 121: Paper feeding tray 122: Pickup roller 150: Fixing unit 180a, 180b: Image pickup unit 210: Controller 230: Engine control unit 231: Scanner unit 232: Printer unit 240: Operation panel 310: Defective part identification unit 320: Noise identification unit 330: Noise avoidance method determination unit 340: Presentation unit 350: Priority Setting unit 360: Print execution unit E1: Streak noise E2, E3: Dot noise

Japanese Unexamined Patent Publication No. 2015-96893

Claims (7)

Periodic parts that are driven at regular intervals and
A noise identification unit that specifies the position of noise that is periodically formed due to a defect in the periodic component,
A noise avoidance method determining unit that determines a noise avoidance method for preventing a document image from being formed at a noise position specified by the noise specifying unit based on the noise position from a plurality of predetermined noise avoidance methods.
A print execution unit that prints the original image on the sheet by a method determined by the noise avoidance method determination unit, and
An image forming apparatus having. The noise avoidance method includes a method of printing so that noise is formed between sheets, a method of printing by changing the orientation of sheets, and a method of printing by changing the position in a direction orthogonal to the sheet conveying direction. One or more of the methods and the method of printing by changing the size,
The noise avoidance method determining unit determines a noise avoidance method that can be implemented from the plurality of noise avoidance methods.
The image forming apparatus according to claim 1. The noise avoidance method determining unit determines a feasible noise avoidance method by sequentially determining whether or not the noise avoidance method can be implemented based on a priority set in advance.
The image forming apparatus according to claim 2. The print execution unit rotates the original image to print so that the noise is formed in a blank area in the original image.
The image forming apparatus according to claim 1. The print execution unit shifts the position of the original image and prints so that the noise is formed in the region where the output density is higher than the specified value in the original image.
The image forming apparatus according to claim 1. It is an image forming method executed by an image forming apparatus having a periodic part which is a part driven in a fixed cycle.
The image forming apparatus
Identify the position of the noise that is periodically formed due to the defect of the periodic component, and
A noise avoidance method for preventing the original image from being formed at the specified noise position is determined based on the noise position from a plurality of predetermined noise avoidance methods.
The original image is printed on the sheet by the determined method.
An image forming method characterized by this. An image forming program for being executed by an image forming apparatus having a periodic part, which is a part driven at a constant cycle.
Identify the position of the noise that is periodically formed due to the defect of the periodic component, and
A noise avoidance method for preventing the original image from being formed at the specified noise position is determined based on the noise position from a plurality of predetermined noise avoidance methods.
The original image is printed on the sheet by the determined method.
An image forming program for causing the image forming apparatus to execute the above.