Image forming system, printing abnormality avoiding method and program

Abstract

To provide an image forming system capable of keeping printing while reducing probability with which printing abnormality occurs, a printing abnormality avoiding method and a program.SOLUTION: An image forming system includes: an image forming unit 14 printing an image on a sheet; a storage control part (control part 16) which has a storage part 17 store a printing condition when printing abnormality occurs in the case that the printing abnormality occurs by printing with the image forming unit 14; a collation part (control part 16) which collates a printing condition of the printing job to a printing condition during the printing abnormality stored to the storage part 17 before performing a printing job; and a determination part (control part 16) which determines whether or not occurrence of printing abnormality is avoidable by changing printing rates of the printing job when the printing condition of the printing job matches the printing condition during the printing abnormality as a result of collation by the collation part.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an image forming system, a method for avoiding a printing error, and a program. [Background technology]

[0002] Conventionally, image forming apparatuses that print (form) images on paper are known. When an image is printed on paper by an image forming apparatus, printing abnormalities such as stains, streaks, glowing spots, color unevenness, and JAM may occur.

[0003] A configuration has been disclosed in which printing conditions when a printing abnormality occurs are stored, and before printing, the printing conditions are compared with the stored printing conditions when the printing abnormality occurred (see, for example, Patent Document 1). The printing conditions include, for example, the model, paper type, basis weight, paper size, print rate, temperature and humidity, and other information that can be acquired by sensors. The configuration described in Patent Document 1 prevents the occurrence of a printing abnormality by stopping printing in advance when the printing conditions match the printing conditions when the printing abnormality occurred. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-30576 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the configuration described in Patent Document 1 halts printing if the printing conditions match the printing conditions when the printing abnormality occurs by comparing the printing conditions. In other words, if the printing conditions match the printing conditions when the printing abnormality occurs, there is a risk that printing will have to be abandoned.

[0006] An object of the present invention is to provide an image forming system, a method for avoiding print abnormalities, and a program for enabling printing to continue while reducing the probability of print abnormalities occurring. [Means for solving the problem]

[0007] The invention described in claim 1 has been made to achieve the above object, In an image forming system, an image forming unit that prints an image on paper; a memory control unit that, when a printing abnormality occurs during printing by the image forming unit, stores in a memory unit the printing conditions at the time of the printing abnormality; a collation unit that collates a printing condition of the print job with the printing condition at the time of the printing abnormality stored in the storage unit before the print job is executed; a determination unit that, when the printing conditions of the print job and the printing conditions at the time of the printing abnormality match as a result of the comparison by the comparison unit, determines whether the occurrence of the printing abnormality can be avoided by changing the printing rate of the print job; The present invention is characterized by comprising:

[0008] The invention described in claim 2 is the image forming system described in claim 1, The printing job may further include a change unit that changes a printing rate of the print job so as not to cause the printing abnormality when the determination unit determines that the printing abnormality can be avoided.

[0009] The invention described in claim 3 is the image forming system described in claim 2, The change unit changes the imposition of the print job so that the printing rate per sheet of paper is uniform.

[0010] The invention described in claim 4 is the image forming system described in claim 2, a cutting unit that cuts the paper on which the image is printed by the image forming unit, The change unit changes the paper on which the image is printed by the image forming unit to paper having a paper size larger than the original paper, and causes the cutting unit to cut the changed paper so that it has the same paper size as the original paper.

[0011] The invention described in claim 5 is the image forming system described in claim 2, The change unit changes the print density of the print job.

[0012] The invention described in claim 6 is the image forming system described in claim 5, The image forming apparatus further includes a display control unit that displays a preview of the image whose print density has been changed by the change unit on a display unit.

[0013] The invention described in claim 7 is the image forming system described in claim 5, The image forming apparatus further includes a print control unit that causes the image forming unit to print a sample of the image, the print density of which has been changed by the change unit, on the paper.

[0014] The invention described in claim 8 is A method for avoiding a printing abnormality in an image forming system having an image forming unit that prints an image on a sheet, comprising: a storage control step of storing, in a storage unit, printing conditions at the time of a printing abnormality occurring during printing by the image forming unit; a comparison step of comparing, before printing of the print job, the print conditions of the print job with the print conditions at the time of the printing abnormality stored in the storage unit; a determination step of determining whether or not the occurrence of the printing abnormality can be avoided by changing a printing rate of the print job when the printing conditions of the print job and the printing conditions at the time of the printing abnormality coincide as a result of the comparison in the comparison step; Includes.

[0015] The invention described in claim 9 is A computer of an image forming system including an image forming unit that prints an image on a sheet of paper, a storage control unit that stores, in a storage unit, printing conditions at the time of occurrence of a printing abnormality in a printing process performed by the image forming unit; a collation unit that collates, before printing of a print job, a printing condition of the print job with the printing condition at the time of the printing abnormality stored in the storage unit; a determination unit that, when the printing conditions of the print job and the printing conditions at the time of the printing abnormality match as a result of the comparison by the comparison unit, determines whether the occurrence of the printing abnormality can be avoided by changing a printing rate of the print job; This is a program that functions as a Effect of the Invention

[0016] According to the present invention, it is possible to continue printing while reducing the probability of occurrence of printing abnormalities. [Brief description of the drawings]

[0017] [Figure 1] 1 is a diagram showing a schematic configuration of an image forming system according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a functional block diagram showing a control structure of the image forming system according to the embodiment. [Diagram 3] 5 is a flowchart showing an example of control of the image forming system according to the embodiment. [Figure 4] FIG. 13 is a diagram showing an example of a printed sheet before imposition is changed; [Diagram 5] FIG. 13 is a diagram showing an example of a printed sheet after imposition has been changed; [Figure 6] 11A and 11B are diagrams illustrating an example of the same image printed on the original paper before and after the paper size is changed. [Figure 7] 11A and 11B are diagrams illustrating an example of a sheet on which images are printed before and after changing the print density. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0019] An image forming system 1 according to the present embodiment includes an image forming apparatus 10, an image reading apparatus 20, and a cutting apparatus 30, as shown in FIGS.

[0020] The image forming apparatus 10 prints (forms) an image on paper based on image data included in a print job received from an external device, etc. Alternatively, the image forming apparatus 10 prints an image on paper based on image data obtained by reading an image from a document. The paper on which the image has been printed is discharged to the image reading apparatus 20.

[0021] As shown in Figures 1 and 2, the image forming device 10 includes an operation unit 11, a display unit 12, a document reading unit 13, an image forming unit 14, a paper feeding unit 15, a control unit 16, a memory unit 17, a controller IF 18, and an image processing unit 19.

[0022] The operation unit 11 includes a touch panel formed so as to cover the display screen of the display unit 12, and various operation buttons such as numeric buttons and a start button. The operation unit 11 outputs an operation signal to the control unit 16 based on a user's operation.

[0023] The display unit 12 is configured with an LCD (Liquid Crystal Display). The display unit 12 displays various screens in accordance with instructions of a display signal input from the control unit 16.

[0024] The document reading unit 13 includes an ADF (automatic document feeder), a scanner, etc. The document reading unit 13 outputs image data obtained by reading an image of a document to the control unit 16.

[0025] The image forming unit 14 forms (prints) an image on a sheet of paper supplied from a paper feed unit 15, based on image data that has been image-processed by an image processing unit 19. The image forming unit 14 includes photoconductor drums 141Y, 141M, 141C, and 141K corresponding to the respective colors of yellow (Y), magenta (M), cyan (C), and black (K), an intermediate transfer belt 142, a secondary transfer roller 143, a fixing unit 144, and the like.

[0026] After being uniformly charged, the photoconductor drum 141Y is scanned and exposed to a laser beam based on yellow image data to form an electrostatic latent image. Then, yellow toner is attached to the electrostatic latent image on the photoconductor drum 141Y, and development is performed. The photoconductor drums 141M, 141C, and 141K are similar to the photoconductor drum 141Y except for the colors they handle, and therefore descriptions thereof will be omitted.

[0027] The toner images of each color formed on the photoconductor drums 141Y to 141K are successively transferred (primary transfer) onto the rotating intermediate transfer belt 142. That is, a color toner image is formed on the intermediate transfer belt 142 in which the toner images of four colors are superimposed. The color toner image on the intermediate transfer belt 142 is transferred all at once onto a sheet of paper by a secondary transfer roller 143 (secondary transfer).

[0028] The fixing unit 144 includes a heating roller that heats the paper onto which the color toner image has been transferred, and a pressure roller that presses the paper, and fixes the color toner image onto the paper by applying heat and pressure.

[0029] The paper feed unit 15 includes paper feed trays 151 to 153, and supplies paper to the image forming unit 14. Each of the paper feed trays 151 to 153 stores paper of a paper type and size that are predetermined for that paper feed tray.

[0030] The control unit 16 includes a CPU, a ROM, and a memory. The CPU reads out various processing programs stored in the ROM, and performs centralized control of the operations of the various parts of the image forming apparatus 10 in accordance with the programs. The ROM is composed of non-volatile semiconductor memory or the like, and stores various processing programs, parameters and files required for executing the programs, etc. The memory is configured with a DRAM or the like, and temporarily stores various data such as programs and image data related to various image processes.

[0031] The storage unit 17 is a non-volatile storage device such as a HDD or semiconductor memory that stores various data such as programs and image data. The storage unit 17 stores data such as program data and various setting data in a manner that allows the control unit 16 to read and write the data. For example, the storage unit 17 stores printing conditions when a printing abnormality occurs.

[0032] A controller IF (Interface) 18 receives a print job transmitted from an external device, etc. The received print job is output to the control unit 16.

[0033] The image processing unit 19 performs necessary image processing on the image data, and transmits the image data after image processing to the image forming unit 14. Image processing includes gradation processing, halftone processing, color conversion processing, etc. Gradation processing is a process of converting the gradation value of each pixel of the image data into a corrected gradation value so that the density characteristics of the image formed on the paper match the target. Halftone processing is an error diffusion process, a screen process using an ordered dither method, etc. Color conversion processing is a process of converting each RGB gradation value into each CMYK gradation value.

[0034] The image reading device 20 is connected to the rear stage of the image forming device 10, and includes a control unit 21, an image reading unit 22, and an image processing unit .

[0035] The control unit 21 includes a CPU, a ROM, a RAM, and the like, and controls the overall operation of each unit of the image reading device 20.

[0036] The image reading unit 22 includes, for example, a linear image sensor (for example, a CCD line sensor), an optical system, a light source, etc. The image reading unit 22 reads the paper on which an image has been formed by the image forming unit 14, and outputs the obtained read image to the image processing unit 23. The paper read by the image reading unit 22 is transported to the cutting device 30.

[0037] The image processing unit 23 generates RGB digital image data after performing various processes on the analog image data input from the image reading unit 22. The various processes include, for example, analog processing, A / D conversion processing, shading processing, etc. The image data generated by the image processing unit 23 is output to the control unit 16 of the image forming apparatus 10.

[0038] The cutting device 30 includes a control unit 31, a transport unit 32, a cutting unit 33, a paper discharge unit 34, and a waste paper box 35. The cutting device 30 is provided with a paper discharge tray T1 on which the paper discharged by the paper discharge unit 34 is stacked.

[0039] The control unit 31 includes a CPU, a ROM, a RAM, and the like, and controls the overall operation of each part of the cutting device 30. The conveying section 32 conveys the paper conveyed from the image reading device 20 to the cutting section 33, and conveys the paper that has been cut by the cutting section 33 to the paper discharge section . The cutting unit 33 cuts the paper conveyed by the conveying unit 32 (paper on which an image has been printed by the image forming unit 14). The paper discharge section 34 discharges the paper conveyed by the conveyance section 32 to the outside of the apparatus (paper discharge tray T1). Waste box 35 is provided below cutting unit 33 and stores cutting waste generated when paper is cut by cutting unit 33.

[0040] Next, the control of the image forming system 1 according to this embodiment will be described with reference to the flowchart of Fig. 3. The control of Fig. 3 is started when the control unit 16 of the image forming apparatus 10 acquires a print job from an external device or the like via the controller IF 18. The control unit 16 controls the image reading device 20 via the control unit 21. The control unit 16 also controls the cutting device 30 via the control unit 31.

[0041] First, the control unit 16 refers to the acquired print job and acquires the printing conditions of the print job (step S101). The printing conditions include, for example, the model, paper type, basis weight, paper size, printing rate, temperature and humidity, and other information that can be acquired by sensors.

[0042] Next, the control unit 16 compares the printing conditions of the acquired print job with the printing conditions at the time of the printing abnormality stored in the storage unit 17 (step S102). That is, the control unit 16 functions as a comparison unit of the present invention.

[0043] Next, the control unit 16 determines whether or not the printing conditions of the print job match the printing conditions when the printing abnormality occurred (step S103). If the control unit 16 determines that the printing conditions match (step S103: YES), the process proceeds to the next step S104. On the other hand, if the control unit 16 determines that the printing conditions do not match (step S103: NO), the process proceeds to step S106.

[0044] In step S104, the control unit 16 judges whether the occurrence of a printing abnormality can be avoided by changing the printing rate of the print job. That is, the control unit 16 functions as a judgment unit of the present invention. For example, if the printing rate of the print job is 80% or more, the printing abnormality is likely to occur. This is because the amount of toner is too large, causing toner scattering, or causing poor fixing of toner in a low temperature environment. Also, if the printing rate of the print job is 20% or less, the printing abnormality is likely to occur. This is because the stiffness of the paper is too low, making it easy for the paper to curl. Therefore, for example, when the printing rate is 85%, the control unit 16 judges that the occurrence of a printing abnormality can be avoided by changing the printing rate to less than 80%. On the other hand, when the printing rate is 60%, for example, the control unit 16 judges that the occurrence of a printing abnormality cannot be avoided even if the printing rate is changed. When the control unit 16 determines that the occurrence of a printing abnormality can be avoided (step S104: YES), the control unit 16 proceeds to the next step S105. On the other hand, if the control unit 16 determines that the occurrence of a printing abnormality cannot be avoided (step S104: NO), it stops printing (step S112).

[0045] Next, the control unit 16 changes the printing rate of the print job so as not to cause a printing abnormality (step S105). That is, the control unit 16 functions as a change unit of the present invention.

[0046] For example, the control unit 16 changes the imposition (printing order) of the print job so that the printing rate per sheet of paper is uniform, thereby making it possible to change the printing rate of the print job. Fig. 4 shows an example of a sheet of paper P after printing before changing the imposition. The example shown in Fig. 4 shows how image data (images) of four pages are imposed and printed on one sheet of paper P. Reference P1 indicates the first sheet of paper on which image G1 of a page with a low print rate is printed. Reference P2 indicates the second sheet of paper on which image G2 of a page with a high print rate is printed. FIG. 5 shows an example of the printed sheet P after the imposition has been changed. In the example shown in Fig. 5, the imposition of the print job is changed so that the printing rate per sheet of paper P is uniform. Specifically, two pages of image G1, a page with a low printing rate, and image G2, a page with a high printing rate, are printed on each sheet of paper P (P1, P2). This makes it possible to change the printing rate of the print job, thereby reducing the probability of printing abnormalities occurring.

[0047] Furthermore, the control unit 16 changes the paper on which the image is printed by the image forming unit 14 to a paper with a paper size larger than the original paper, thereby making it possible to change the printing rate of the print job. Fig. 6 shows an example of the same image printed on the original paper P3 before changing the paper size and on the paper P4 after changing the paper size. Fig. 6(A) is a diagram showing an example of an image printed on the original paper P3. Fig. 6(B) is a diagram showing an example of an image printed on the paper P4, which is larger in paper size than the original paper P3. Fig. 6 shows an example in which the print rate of the original paper P3 is too high, which may cause printing abnormalities, so the paper size is changed to paper P4, which has a larger paper size. In the example shown in Fig. 6, the print rate of the print job is reduced by changing from the original paper P3, which has a higher print rate, to paper P4, which has a larger paper size. This reduces the probability of printing abnormalities occurring. If the coverage rate of the original paper is too low and there is a risk of print errors occurring, it is a good idea to change to paper with a smaller size, which will increase the coverage rate of the print job and reduce the chance of print errors occurring. When the paper size is changed to the larger paper P4, the control unit 16 controls the cutting unit 33 to cut the margins of the changed paper P4 so that it has the same paper size as the original paper P3. This makes it possible to produce the same final product as if it were printed on the original paper P3.

[0048] Furthermore, the control unit 16 changes the print density of the print job, thereby making it possible to change the printing rate of the print job. Fig. 7 shows an example of paper P on which images are printed before and after changing the print density. Fig. 7(A) is an example of paper P on which an original image G3 is printed before changing the print density. Fig. 7(B) is an example of paper P on which an image G4 is printed after changing the print density. 7 shows an example in which the paper P on which the original image G3 is printed has a printing rate that is too high, which may cause printing abnormalities, and so the paper P is changed to one on which an image G4 with a lighter print density is printed. In the example shown in FIG. 7, the printing rate of the print job is lowered by changing from the original image G3, which has a higher printing rate, to an image G4 with a lighter print density. This makes it possible to reduce the probability of printing abnormalities occurring. If the printing rate of the paper P on which the original image is printed is too low and there is a risk of printing abnormalities occurring, it is advisable to print an image with a darker print density. This makes it possible to increase the printing rate of the print job, thereby reducing the probability of printing abnormalities occurring.

[0049] Next, the control unit 16 prints (forms) an image on a sheet of paper based on the image data included in the print job (step S106). The sheet of paper on which the image has been printed is transported to the image reading device 20.

[0050] Next, the control unit 16 controls the image reading unit 22 to read the paper on which the image is printed (step S107). The read image obtained by the image reading unit 22 is output to the control unit 16. The paper read by the image reading unit 22 is discharged to the paper output tray T1 via the cutting device 30.

[0051] Next, the control unit 16 compares the expected image based on the image data included in the print job with the read image acquired in step S108 (step S108).

[0052] Next, the control unit 16 compares the expected image with the read image and determines whether or not a printing abnormality has occurred (step S109). Printing abnormalities include, for example, stains, streaks, glowing spots, color unevenness, JAM, and the like. When the control unit 16 determines that a printing abnormality has occurred (step S109: YES), the process proceeds to the next step S110. On the other hand, if the control unit 16 determines that no printing abnormality has occurred (step S109: NO), the process proceeds to step S111.

[0053] In step S111, the control unit 16 stores the printing conditions used in printing in step S106 in the storage unit 17 (step S110). That is, the control unit 16 functions as a storage control unit of the present invention that stores, when a printing abnormality occurs, the printing conditions used at the time of the printing abnormality in the storage unit 17.

[0054] Next, the control unit 16 determines whether or not the printing is completed (step S111). When the control unit 16 determines that the printing is completed (step S111: YES), the process ends. On the other hand, if the control unit 16 determines that the printing is not completed (step S111: NO), the process proceeds to step S102, and then the process from step S102 onwards is repeated.

[0055] As described above, the image forming system 1 according to this embodiment includes the image forming unit 14 that prints an image on paper, a storage control unit (control unit 16), a collation unit (control unit 16), and a judgment unit (control unit 16). When a printing abnormality occurs during printing by the image forming unit 14, the storage control unit stores the printing conditions at the time of the printing abnormality in the storage unit 17. Before printing of a print job, the collation unit compares the printing conditions of the print job with the printing conditions at the time of the printing abnormality stored in the storage unit 17. When the collation by the collation unit shows that the printing conditions of the print job match the printing conditions at the time of the printing abnormality, the judgment unit judges whether the occurrence of the printing abnormality can be avoided by changing the printing rate of the print job. Therefore, the image forming system 1 according to the present embodiment can reduce the probability of occurrence of a printing abnormality. Furthermore, even if the printing conditions of a print job match the printing conditions when a printing abnormality occurs, printing can be continued.

[0056] The printer also includes a change unit (control unit 16) that changes the printing rate of the print job so as not to cause the printing abnormality when it is determined that the printing abnormality can be avoided. Therefore, it is possible to reduce the probability of a printing abnormality occurring. Also, even if the printing conditions of the print job match the printing conditions when a printing abnormality occurs, printing can be continued.

[0057] The change unit also changes the imposition of the print job so that the printing rate per sheet of paper is uniform. Therefore, the printing rate of the print job can be easily changed, thereby reducing the probability of occurrence of printing abnormalities.

[0058] The printer also includes a cutting unit 33 that cuts the paper on which an image has been printed by the image forming unit 14. The change unit changes the paper on which an image is printed by the image forming unit 14 to paper with a larger paper size than the original paper. The change unit causes the cutting unit 33 to cut the changed paper so that it has the same paper size as the original paper. Therefore, the printing rate of the print job can be easily changed, the probability of occurrence of printing abnormalities can be reduced, and the same output as that obtained by printing on the original paper can be produced.

[0059] The change unit also changes the print density of the print job. Therefore, the printing rate of the print job can be easily changed, the probability of occurrence of printing abnormalities can be reduced, and the same output as that obtained by printing on the original paper can be produced.

[0060] Although the present invention has been specifically described above based on an embodiment thereof, the present invention is not limited to the above embodiment and can be modified without departing from the spirit of the present invention.

[0061] For example, in the above embodiment, the printing rate of the print job is changed when the printing conditions of the print job and the printing conditions when a printing abnormality occurs match, but the present invention is not limited to this. For example, the printing rate of the print job may be changed when the printing rate of the print job and the printing rate when a printing abnormality occurs match. That is, when the printing rate of the print job and the printing rate when a printing abnormality occurs match, the control unit 16 determines whether or not the occurrence of the printing abnormality can be avoided by changing the printing rate of the print job. When it is determined that the occurrence of the printing abnormality can be avoided, the control unit 16 changes the printing rate of the print job so as not to cause the printing abnormality.

[0062] Furthermore, the control unit 16 may cause a preview of an image G4 (see FIG. 7(B)) with a changed print density to be displayed on the display unit 12. That is, the control unit 16 functions as a display control unit of the present invention. This allows the user to concretely imagine the printed product, and thus allows the user to arbitrarily select whether to prioritize suppression of printing abnormalities or image quality.

[0063] Furthermore, the control unit 16 may cause the image forming unit 14 to print a sample of the image G4 (see FIG. 7B) whose print density has been changed on a sheet of paper. That is, the control unit 16 functions as the print control unit of the present invention. This allows the user to concretely imagine the printed product, and thus allows the user to arbitrarily select whether to prioritize suppression of printing abnormalities or image quality.

[0064] In addition, the detailed configurations and operations of each device constituting the image forming system may be modified as appropriate without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0065] 1. Image forming system 10 Image forming device 11 Control section 12 Display section 13 Document reading unit 14 Image forming section 141Y, 141M, 141C, 141K Photoconductor drum 142 Intermediate transfer belt 143 Secondary transfer roller 144 Fixing part 15 Paper feed section 151~153 Paper Tray 16 Control unit (collation unit, judgment unit, change unit, storage control unit, display control unit, print control unit) 17 Memory section 18 Controller Interface 19 Image processing section 20 Image reader 21 Control section 22 Image reading unit 23 Image processing section 30 Cutting device 31 Control Unit 32 Conveyor 33 Cutting section 34 Paper ejection section 35 Trash Can T1 Output Tray

Claims

1. an image forming unit that prints an image on paper; a memory control unit that, when a printing abnormality occurs during printing by the image forming unit, stores in a memory unit the printing conditions at the time of the printing abnormality; a collation unit that collates a printing condition of the print job with the printing condition at the time of the printing abnormality stored in the storage unit before the print job is executed; a determination unit that, when the printing conditions of the print job and the printing conditions at the time of the printing abnormality match as a result of the comparison by the comparison unit, determines whether the occurrence of the printing abnormality can be avoided by changing the printing rate of the print job; An image forming system comprising:

2. 2. The image forming system according to claim 1, further comprising a change unit that changes the printing rate of the print job so as not to cause the printing abnormality when the judgment unit judges that the occurrence of the printing abnormality can be avoided.

3. 3. The image forming system according to claim 2, wherein the change unit changes the imposition of the print job so that the printing rate per sheet of paper is uniform.

4. a cutting unit that cuts the paper on which the image is printed by the image forming unit, The image forming system according to claim 2, characterized in that the change unit changes the paper on which the image is printed by the image forming unit to paper having a paper size larger than the original paper, and causes the cutting unit to cut the changed paper so that it has the same paper size as the original paper.

5. 3. The image forming system according to claim 2, wherein the change unit changes the print density of the print job.

6. 6. The image forming system according to claim 5, further comprising a display control unit that displays a preview of the image in which the print density has been changed by the change unit on a display unit.

7. 6. The image forming system according to claim 5, further comprising a print control unit that causes the image forming unit to print a sample of the image, the print density of which has been changed by the change unit, on the paper.

8. A method for avoiding a printing abnormality in an image forming system having an image forming unit that prints an image on a sheet, comprising: a storage control step of storing, in a storage unit, printing conditions at the time of occurrence of a printing abnormality in a printing process performed by the image forming unit; a comparison step of comparing, before printing of the print job, the print conditions of the print job with the print conditions at the time of the printing abnormality stored in the storage unit; a determination step of determining whether or not the occurrence of the printing abnormality can be avoided by changing a printing rate of the print job when the printing conditions of the print job and the printing conditions at the time of the printing abnormality coincide as a result of the comparison in the comparison step; Includes methods to avoid printing abnormalities.

9. A computer of an image forming system including an image forming unit that prints an image on a sheet of paper, a storage control unit that stores, in a storage unit, printing conditions at the time of occurrence of a printing abnormality in a printing process performed by the image forming unit; a collation unit that collates, before printing of a print job, a printing condition of the print job with the printing condition at the time of the printing abnormality stored in the storage unit; a determination unit that, when the printing conditions of the print job and the printing conditions at the time of the printing abnormality match as a result of the comparison by the comparison unit, determines whether the occurrence of the printing abnormality can be avoided by changing a printing rate of the print job; A program to function as a

Images