JP6131825B2 - Image forming apparatus and program - Google Patents

Description

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

  Patent Document 1 discloses a printing apparatus that executes a printing process on a print medium, and includes an input unit that inputs first image data to be printed on the print medium, and the first unit that is input by the input unit. Print processing means for executing print processing on the print medium based on image data; and a second for determining a print defect by reading the print medium on which the first image data has been printed by the print processing means. When the predetermined post-processing is performed on the reading medium for acquiring the image data and the print medium on which the first image data is printed, the second used for determining the printing failure. Specific processing for specifying a determination region in the image data, which is a determination region representing an image region that can be visually recognized on the print medium even after the predetermined post-processing, is performed, and the first image data Is compared with the second image data in the determination area to determine whether there is a printing defect, and the predetermined post-processing is performed on the print medium on which the first image data is printed. If not, the determination process is not performed, and the first image data and the second image data are compared to determine whether there is a printing defect. A printing apparatus is disclosed.

  On the other hand, in Patent Document 2, a printing unit that executes a printing process on a sheet based on first image data, and a second image data generated by reading the sheet on which the printing process has been executed are described in the first document. An acquisition unit that acquires a result of an inspection process for inspecting whether or not there is a printing defect in the printing process by comparing with the image data of 1 and when the printing process is resumed after the printing process is interrupted, After executing the printing process for the specific number of sheets, after confirming that the result of the inspection process for the specific number of sheets does not indicate a printing failure, the printing process for the sheet following the specific number of sheets is performed as described above. And a control unit that controls the printing unit to start the printing apparatus.

  Patent Document 3 discloses a plurality of nozzle rows that eject liquid, a control unit that ejects liquid from the nozzle rows to a medium to form an image, an imaging device that reads the formed image, and the imaging A detection unit that detects a print defect by comparing the image read by the apparatus with a master image, and the detection unit is a temporary detection pattern and an image that should be the master image at the start of printing. An image obtained by capturing the medium on which a master image is printed in a predetermined order is read, and after confirming that there is no defect by the defect detection pattern, the temporary master image is registered as the master image. Is disclosed.

Japanese Patent No. 4562188 JP 2012-011769 A JP 2010-173289 A

  An object of the present invention is to provide an image forming apparatus and a program capable of suppressing excessive maintenance for image formation defects.

In order to achieve the above object, an image forming apparatus according to claim 1 includes a forming unit that forms an image on a recording medium, and a reading unit that reads a formed image that is an image formed on the recording medium by the forming unit. And a tolerance level indicating the level of failure in the forming means for each predetermined stage, and a time allowed for performing maintenance or rediagnosis for the failure for each level of the failure level. Storage means for storing the timing in advance; first image information used for forming an image by the forming means; and second image information obtained by reading the formed image formed by the image by the reading means. and based on the comparison result in a predetermined division each region, and diagnosis means for diagnosing the degree failure for each segmented region, predetermined by the forming means When forming an image of a manuscript, based on document image information indicating an image of the document, the diagnostic unit obtains the segmented region including an image formed on the recording medium by the forming unit. of about poor, the degree highest, and deriving means for deriving as an overall said about defective images of the document, in the above allowable implementation time Kemah corresponding to the order of defective derived by the deriving means Execution means for executing a predetermined process for performing at least one of maintenance and re-diagnosis.

According to a second aspect of the present invention, in the first aspect of the present invention, the derivation unit continuously outputs a plurality of original images in which at least a part of an area where an image is formed by the forming unit is different from each other. In this case, the overall degree of the defect is derived for all image forming areas formed by the images of the plurality of documents.

Further, in the invention described in claim 3 , in the invention described in claim 1 or claim 2 , when the execution unit executes a predetermined process for performing the maintenance, the execution unit continues to the process. A predetermined process for performing the re-diagnosis is executed.

The invention according to claim 4 is the invention according to any one of claims 1 to 3 , wherein the permissible execution time is a time for performing at least one of maintenance and rediagnosis for the defect. It is at least one of an allowable elapsed time, the allowable time, and the number of images formed on the recording medium by the allowable forming unit.

Furthermore, the invention according to claim 5 is the invention according to any one of claims 1 to 4 , wherein the forming means forms an image by an electrophotographic system or an ink jet system.

On the other hand, in order to achieve the above object, a program according to claim 6 includes: a forming unit that forms an image on a recording medium; and a reading unit that reads a formed image that is an image formed on the recording medium by the forming unit. And a tolerance level indicating the level of failure in the forming means for each predetermined stage, and a time allowed for performing maintenance or rediagnosis for the failure for each level of the failure level. A program for controlling an image forming apparatus including a storage unit that stores a time in advance, wherein the computer includes first image information used for forming an image by the forming unit, and the image forming unit configured to form the image. Based on the result of comparing the second image information obtained by reading the formed image with the reading means for each predetermined divided area, And diagnosis means for diagnosing the degree failure for each frequency band, the case of forming an image of a predetermined document by the forming means, based on the original image information indicating an image of the document, on the recording medium by the forming means Deriving means for deriving the highest degree of the degree of defect obtained by the diagnostic means for the segmented region including the image to be formed as the overall degree of defect of the document image; and executing means for executing the maintenance and predetermined processing for performing at least one of the re-diagnosis in the allowable implementation time Kemah corresponding to the order of defective derived by deriving means, for functioning as a Is.

According to the first and sixth aspects of the invention, it is possible to obtain an effect that it is possible to suppress excessive maintenance for image formation defects as compared with the case where the present invention is not applied.

According to the second aspect of the present invention, it is possible to effectively suppress excessive maintenance even when forming images of a plurality of documents in which at least a part of a region where an image is formed is different from each other. The effect of is obtained.

Further, according to the invention described in claim 3 , the effect that the effect of maintenance can be easily confirmed is obtained.

According to the fourth aspect of the present invention, when at least one of the elapsed time and time of the present invention is applied, excessive maintenance can be performed more easily than when the number of image formation sheets of the present invention is applied. The effect that it can suppress is acquired. According to the fourth aspect of the present invention, when applying the number of image forming sheets according to the present invention, it is possible to suppress excessive maintenance more effectively than when applying at least one of elapsed time and time. The effect that it can do is acquired.

Furthermore, according to the fifth aspect of the present invention, there is an effect that excessive maintenance can be suppressed in an apparatus for forming an image by an electrophotographic system or an inkjet system.

1 is a side cross-sectional view illustrating an example of a configuration of an image forming apparatus according to an embodiment. It is a bottom view which shows the structure of the inkjet recording head which concerns on embodiment. 1 is a block diagram illustrating a configuration of a main part of an electric system of an image forming apparatus according to an embodiment. 1 is a diagram for explaining an overall configuration of an image forming apparatus according to an embodiment and a printing operation. FIG. FIG. 6 is a diagram for explaining a failure diagnosis operation in the image forming apparatus according to the embodiment. It is a figure for demonstrating the detection of the printing defect which concerns on embodiment. It is a figure which shows an example of the defect level table which concerns on embodiment. It is a figure for demonstrating the failure diagnosis result for every image section which concerns on embodiment. It is a figure for demonstrating the update of the failure diagnosis result which concerns on embodiment. It is a figure for demonstrating the algorithm of the update of the failure diagnosis result which concerns on embodiment. It is a figure for demonstrating the update of the failure diagnosis result after the maintenance execution which concerns on embodiment. It is a figure for demonstrating the defect determination result in case the maintenance which concerns on embodiment is postponed. It is a figure for demonstrating the defect determination result in case the maintenance which concerns on embodiment is required. FIG. 10 is a diagram for explaining a defect determination result in the case of a print job composed of a plurality of pages according to the embodiment. FIG. 10 is a diagram for explaining a defect determination result in the case of a color print job according to the embodiment. 6 is a flowchart showing a flow of processing of an image forming processing program according to the embodiment. It is a flowchart which shows the flow of a process of the failure diagnosis and maintenance process subroutine which concerns on embodiment. It is a flowchart which shows the flow of a process of the maintenance process subroutine which concerns on embodiment. It is a flowchart which shows the flow of a process of the defect diagnosis processing subroutine which concerns on embodiment. 6 is a flowchart illustrating a processing flow of a print processing subroutine according to the embodiment.

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

  FIG. 1 is a side sectional view showing a configuration of an image forming apparatus 10 according to the present embodiment. As shown in the figure, the image forming apparatus 10 is provided with a paper feeding / conveying section 12 that feeds and conveys recording paper P as a recording medium. On the downstream side in the conveyance direction of the recording paper P of the paper feeding / conveying section 12, a color material (pigment in this embodiment) reacts with the ink on the recording surface (front surface) of the recording paper P along the conveyance direction. A processing liquid application unit 14 that applies a processing liquid for aggregating and promoting separation of the colorant and the solvent, an image forming unit 16 that forms an image on the recording surface of the recording paper P, and an image formed on the recording surface A drying unit 18 for drying, an image fixing unit 20 for fixing the dried image on the recording paper P, and a discharge conveyance unit 24 for conveying the recording paper P on which the image is fixed to the discharge unit 22 are sequentially provided.

  The paper feeding / conveying unit 12 includes a storage unit 26 that stores the recording paper P. In addition, a motor 30 is provided in the accommodating portion 26. Further, the storage unit 26 is provided with a paper feeding device (not shown), and the recording paper P is sent from the storage unit 26 to the treatment liquid coating unit 14 by the paper feeding device.

The treatment liquid application unit 14 includes an intermediate conveyance drum 28 </ b> A and a treatment liquid application drum 36.
The intermediate conveyance drum 28A is rotatably disposed in a region sandwiched between the storage unit 26 and the treatment liquid coating drum 36, and a belt 32 is stretched between the rotation shaft of the intermediate conveyance drum 28A and the rotation shaft of the motor 30. Has been. Therefore, when the rotational driving force of the motor 30 is transmitted to the intermediate transport drum 28A via the belt 32, the intermediate transport drum 28A rotates in the direction of arrow A.

  The intermediate conveyance drum 28A is provided with a holding member 34 that holds the recording paper P with the leading end of the recording paper P interposed therebetween. Accordingly, the recording paper P sent out from the storage unit 26 to the treatment liquid application unit 14 is held on the outer peripheral surface of the intermediate conveyance drum 28A via the holding member 34, and is transferred to the treatment liquid application drum 36 by the rotation of the intermediate conveyance drum 28A. Be transported.

  Note that the intermediate conveyance drums 28B to 28E, the processing liquid coating drum 36, the image forming drum 44, the ink drying drum 56, the image fixing drum 62, and the discharge conveyance drum 68, which will be described later, also have a holding member 34 as in the intermediate conveyance drum 28A. Is provided. The holding member 34 transfers the recording paper P from the upstream drum to the downstream drum.

  The rotating shaft of the treatment liquid coating drum 36 is connected to the rotating shaft of the intermediate transport drum 28A by a gear (not shown), and rotates by receiving the rotational force of the intermediate transport drum 28A.

  The recording paper P transported by the intermediate transport drum 28 </ b> A is transferred to the processing liquid coating drum 36 via the holding member 34 of the processing liquid coating drum 36 and transported while being held on the outer peripheral surface of the processing liquid coating drum 36. Is done.

  A processing liquid application roller 38 is disposed in contact with the outer peripheral surface of the processing liquid application drum 36 above the processing liquid application drum 36, and the outer peripheral surface of the processing liquid application drum 36 is processed by the processing liquid application roller 38. A processing liquid is applied to the recording surface of the upper recording paper P.

  The recording paper P coated with the processing liquid by the processing liquid coating unit 14 is conveyed to the image forming unit 16 by the rotation of the processing liquid coating drum 36.

  The image forming unit 16 includes an intermediate conveyance drum 28 </ b> B and an image forming drum 44. The rotation shaft of the intermediate transport drum 28B is connected to the rotation shaft of the processing liquid coating drum 36 via a gear (not shown), and rotates by receiving the rotational force of the processing liquid coating drum 36.

  The recording paper P conveyed by the treatment liquid application drum 36 is transferred to the intermediate conveyance drum 28B via the holding member 34 of the intermediate conveyance drum 28B of the image forming unit 16, and is held on the outer peripheral surface of the intermediate conveyance drum 28B. It is conveyed in the state.

  The rotation shaft of the image forming drum 44 is connected to the rotation shaft of the intermediate conveyance drum 28B via a gear (not shown), and rotates by receiving the rotational force of the intermediate conveyance drum 28B.

  The recording paper P transported by the intermediate transport drum 28 </ b> B is transferred to the image forming drum 44 via the holding member 34 of the image forming drum 44 and transported while being held on the outer peripheral surface of the image forming drum 44.

Above the image forming drum 44, a head unit 46 is disposed adjacent to the outer peripheral surface of the image forming drum 44. The head unit 46 includes four ink jet recording heads 48 corresponding to four colors of yellow (Y), magenta (M), cyan (C), and black (K), and these ink jet recording heads. 48 are arranged along the circumferential direction of the image forming drum 44 and are described later in synchronization with a clock signal of the CPU 100 described later so as to overlap the processing liquid layer formed on the recording surface of the recording paper P by the processing liquid application unit 14. An image is formed by ejecting ink droplets from the nozzle 48a.
Note that the processing liquid may be ejected from the nozzles of the ink jet recording head 48 according to the present embodiment, but in the present embodiment, a case where ink droplets are ejected will be described as an example.

FIG. 2 shows the arrangement of the nozzles 48a in each inkjet recording head 48 in the present embodiment.
In the present embodiment, the number and arrangement of the nozzles 48a of each ink jet recording head 48 are not particularly limited, but as an example, N nozzles 48a-1, ..., 48a-N are arranged in one row. The inkjet recording head 48 is configured to be a long head in accordance with the width of the recording paper P. Therefore, the ink jet recording head 48 according to the present embodiment is a paper width image forming type (so-called Full Width Array (FWA)) head that forms an image in one pass on the recording paper P that is continuously conveyed. Of course, the present invention is also applied to an image forming apparatus that performs image formation by so-called multi-pass in which the inkjet recording head 48 passes a plurality of times within the paper width.

  Further, the ink jet recording head 48 according to the present embodiment is divided into 48 divided heads 48-1 to 48-M. As an example, the division head is configured by dividing a substrate on which the nozzles 48a are mounted, and each substrate is individually driven by an individual nozzle drive circuit (not shown). The divided ink jet recording heads 48-1 to 48-M may be arranged linearly or in a staggered manner.

  Here, the arrangement of the nozzles 48a in the inkjet recording head 48 is not limited to the above, and the nozzles 48a may be arranged in a plurality of rows, and the nozzles 48a in a plurality of rows may be alternately arranged two-dimensionally in a staggered manner. Also good. Further, the ink jet recording head 48 may not be constituted by a plurality of ink jet recording heads 48-1 to 48 -M but may be constituted by a single unit.

  The recording paper P on which the image is formed on the recording surface by the image forming unit 16 is conveyed to the drying unit 18 by the rotation of the image forming drum 44.

  The drying unit 18 includes an intermediate conveyance drum 28 </ b> C and an ink drying drum 56. The rotation shaft of the intermediate conveyance drum 28 </ b> C is connected to the rotation shaft of the image forming drum 44 through a gear (not shown), and rotates by receiving the rotational force of the image forming drum 44.

  The recording paper P conveyed by the image forming drum 44 is transferred to the intermediate conveyance drum 28C via the holding member 34 of the intermediate conveyance drum 28C, and conveyed while being held on the outer peripheral surface of the intermediate conveyance drum 28C.

  The rotation shaft of the ink drying drum 56 is connected to the rotation shaft of the intermediate conveyance drum 28C via a gear (not shown), and rotates by receiving the rotational force of the intermediate conveyance drum 28C.

  The recording paper P conveyed by the intermediate conveyance drum 28 </ b> C is transferred to the ink drying drum 56 via the holding member 34 of the ink drying drum 56 and conveyed while being held on the outer peripheral surface of the ink drying drum 56.

  Above the ink drying drum 56, a warm air heater 58 is disposed in the vicinity of the outer peripheral surface of the ink drying drum 56. Excess solvent in the image formed on the recording paper P is removed by the warm air from the warm air heater 58. The recording paper P on which the image on the recording surface has been dried by the drying unit 18 is conveyed to the image fixing unit 20 by the rotation of the ink drying drum 56.

  The image fixing unit 20 includes an intermediate conveyance drum 28D and an image fixing drum 62. The rotation shaft of the intermediate transport drum 28D is connected to the rotation shaft of the ink drying drum 56 via a gear (not shown), and rotates by receiving the rotational force of the ink drying drum 56.

  The recording paper P conveyed by the ink drying drum 56 is transferred to the intermediate conveyance drum 28D via the holding member 34 of the intermediate conveyance drum 28D, and conveyed while being held on the outer peripheral surface of the intermediate conveyance drum 28D.

  The rotation shaft of the image fixing drum 62 is connected to the rotation shaft of the intermediate conveyance drum 28D via a gear (not shown), and rotates by receiving the rotational force of the intermediate conveyance drum 28D.

  The recording paper P transported by the intermediate transport drum 28 </ b> D is delivered to the image fixing drum 62 via the holding member 34 of the image fixing drum 62 and transported while being held on the outer peripheral surface of the image fixing drum 62.

Above the image fixing drum 62, a fixing roller 64 having a heater inside is disposed in a state where the outer peripheral surface of the image fixing drum 62 can be pressed or separated. The recording paper P held on the outer peripheral surface of the image fixing drum 62 is sandwiched between the outer peripheral surface of the image fixing drum 62 and the outer peripheral surface of the fixing roller 64, and is in the state of being pressed against the outer peripheral surface of the fixing roller 64. As a result, the color material of the image formed on the recording surface of the recording paper P is fused to the recording paper P, and the image is fixed on the recording paper P. The recording paper P on which the image is fixed by the image fixing unit 20 is
The image fixing drum 62 is conveyed to the discharge conveyance unit 24 by the rotation.

  The discharge transport unit 24 includes an intermediate transport drum 28E and a discharge transport drum 68. The rotation shaft of the intermediate conveyance drum 28E is connected to the rotation shaft of the image fixing drum 62 through a gear (not shown), and rotates by receiving the rotational force of the image fixing drum 62.

  The recording paper P conveyed by the image fixing drum 62 is transferred to the intermediate conveyance drum 28E via the holding member 34 of the intermediate conveyance drum 28E, and conveyed while being held on the outer peripheral surface of the intermediate conveyance drum 28E.

  The rotation shaft of the discharge conveyance drum 68 is connected to the rotation shaft of the intermediate conveyance drum 28E via a gear (not shown), and rotates by receiving the rotational force of the intermediate conveyance drum 28E.

  The recording paper P conveyed by the intermediate conveyance drum 28E is delivered to the discharge conveyance drum 68 via the holding member 34 of the discharge conveyance drum 68, and is held on the outer peripheral surface of the discharge conveyance drum 68 to the discharge unit 22. Be transported.

In addition, the image forming apparatus 10 according to the present embodiment has an inline sensor as a reading unit for reading an image of a document on which an image has been formed or an image of a test pattern to be described later formed on the image fixing drum 62. 80.
The in-line sensor 80 according to the present embodiment reads an image formed on the recording paper P while the recording paper P is being conveyed to the discharge conveyance unit 24 while being held on the outer peripheral surface of the image fixing drum 62. Is arranged.

  The inline sensor 80 according to the present embodiment includes a light emitting unit and a light receiving unit (not shown), and light emitted from the light emitting unit is reflected by the recording paper P, and the reflected light is detected by the light receiving unit. Thus, the reflection optical density (so-called OD (Optical Density) value) of the image forming area of the recording paper P is measured. The inline sensor 80 according to the present embodiment is not limited to the reflective inline sensor, and a transmissive inline sensor may be used.

  Next, with reference to FIG. 3, the main configuration of the electrical system of the image forming apparatus 10 according to the present embodiment will be described.

  As shown in FIG. 1, the image forming apparatus 10 includes a CPU (Central Processing Unit) 100, a storage unit 110, and a UI (User Interface) panel 108. The storage unit 110 includes a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 104, and an NVM (Non Volatile Memory) 106.

  The CPU 100 governs the overall operation of the image forming apparatus 10. Of the storage unit 110, the ROM 102 is a storage medium in which a control program for controlling the operation of the image forming apparatus 10, an image formation processing program to be described later, various parameters, and the like are stored in advance. The RAM 104 is a storage medium used as a work area when executing various programs. The NVM 106 is a non-volatile storage medium that stores various types of information that must be retained even when the power switch of the apparatus is turned off.

The UI panel 108 includes a touch panel display or the like in which a transmissive touch panel is superimposed on a display, and various types of information are displayed on the display surface of the display. Also,
When the user touches the touch panel, desired information and instructions, for example, instructions for starting an image forming processing program, and the like are input.

  The CPU 100, the storage unit 110 (ROM 102, RAM 104, NVM 106), and the UI panel 108 are connected to each other via a bus BUS such as a system bus. Therefore, the CPU 100 performs access to the ROM 102, RAM 104, and NVM 106, displays various information on the UI panel 108, and grasps the contents of user operation instructions on the UI panel 108.

  Further, the image forming apparatus 10 includes a recording head controller 116 and a motor controller 118.

  The recording head controller 116 controls the operation of the ink jet recording head 48 in accordance with instructions from the CPU 100. The motor controller 118 controls the operation of the motor 30.

  The recording head controller 116 and the motor controller 118 are also connected to the bus BUS. Therefore, the CPU 100 controls the operation of the recording head controller 116 and the motor controller 118.

The image forming apparatus 10 according to the present embodiment further includes a scanner unit 120 that reads a document or the like and generates image information. The scanner unit 120 is also connected to the bus BUS,
It is controlled by the CPU 100.
Note that the inline sensor 80 described above is also connected to the bus BUS, and the CPU 100 can also access the inline sensor 80.

  Next, with reference to FIG. 4 and FIG. 5, the overall configuration of the image forming apparatus 10 according to the present embodiment, the image forming (hereinafter sometimes referred to as “printing”) operation, and the flow of a failure diagnosis operation described later. explain. During these operations, the inline sensor 80 according to the present embodiment has a function as an image reading apparatus when reading a test pattern, which will be described later, mainly in a failure diagnosis operation.

  First, an overall configuration of the image forming apparatus 10 according to the present embodiment and a printing operation executed by the image forming apparatus 10 will be described with reference to FIG.

  First, when an operator operates the scanner unit 120 to read an original of one unit of printing processing (job), image information of an original image (original image) is generated, and the image information of the original image is the CPU 100. Sent to. In addition, the operator operates the UI panel 108 and the like to specify the number of copies to be printed and instruct to print the original image.

The CPU 100 includes a program having a function as an image processing unit 100A that performs predetermined processing on image information and an image comparison unit 100B that extracts a difference between the image information.
CPU 100 converts image information of a document image for which printing has been instructed into image information of a print image (image to be printed by image forming unit 16) in image processing unit 100A, and converts the image information of the print image to an image. Send to forming unit 16.

In response to the printing instruction, the paper (recording paper P) is supplied from the paper feeding / conveying section 12, and the supplied paper passes through the paper conveying path (conveying path from the treatment liquid coating unit 14 to the discharge conveying unit 24 in FIG. 1). To the discharge unit 22.
A print image is printed on a sheet in the image forming unit 16 in the middle of the sheet conveyance path to obtain a printed matter. The printed matter is conveyed to the discharge unit 22 at the end of the sheet conveyance path and discharged.

  Note that the image forming apparatus 10 according to the present exemplary embodiment may interrupt printing that is being performed due to an abnormality or the like inside the image forming apparatus 10. In this case, the image forming apparatus 10 may To notify. In the image forming apparatus 10 according to the present embodiment, printing that is being performed is interrupted by an instruction from the operator. Further, in the image forming apparatus 10, maintenance is performed according to an instruction from the operator. Notification to the operator and instructions from the operator are executed by the CPU 100 via the UI panel 108 or the like.

Next, the failure diagnosis operation according to the present embodiment will be described with reference to FIG.
When the CPU 100 receives an instruction to perform a failure diagnosis of the image forming apparatus 10, the image of a test print image (a test pattern described later), which is a type of print image, is stored in a storage unit such as the storage unit 110 (ROM 102). Read information. Image information of the read test print image is sent to the image forming unit 16. The CPU 100 instructs the image forming unit 16 to perform the printing of the test print image, and further instructs the inline sensor 80 to read the image of the test print image in order to obtain the print image of the test print image.

When an instruction for printing a test print image and reading an image of a printed matter of the test print image is given, the paper is supplied from the paper feed conveyance unit 12 and the supplied paper is conveyed on the paper conveyance path.
In the image forming unit 16 in the middle of the paper transport path, a test print image is printed on the paper to generate a printed material, and the printed material is transported to the discharge unit 22 at the end of the paper transport path. The printed matter is read by the in-line sensor 80 in the middle of conveyance, and image information of the printed matter image of the test print image is generated. The image information of the printed image of the test print image generated by the inline sensor 80 is compared with the image information of the test print image in the image comparison unit 100B, and a failure diagnosis is executed. If the printing is normal, the image information of the printed image generated by the inline sensor 80 and compared by the image comparison unit 100B is the image information of the test print image read from the storage unit such as the storage unit 110 (ROM 102). And in pixel units.

By the way, in the image forming apparatus, there is a problem in the printing operation or the like (in this embodiment,
If this occurs, the maintenance of the printing defect is performed.
Generally, the influence of the printing defect is eliminated. The print defect may be detected automatically by the image forming apparatus, or may be detected in a defect diagnosis performed periodically. Further, the elimination of the influence of printing defects may be automatically executed by the image forming apparatus or may be executed by an operator.

  At this time, the quality of the printed matter is improved by frequently performing failure diagnosis and performing maintenance frequently regardless of the degree of the printing failure every time a printing failure is found. However, the operation rate of the image forming apparatus decreases due to the stoppage of the image forming apparatus due to frequent failure diagnosis and maintenance.

  In addition, depending on the relationship between the content of an image such as a document and the content of a print defect (hereinafter sometimes referred to as “defective content”), the quality does not change even when maintenance is performed. In some cases, the printing may be performed normally, and it is not always necessary to perform maintenance for the current printing.

  Accordingly, an object of the present invention is to realize suppression of excessive maintenance for image formation defects. Therefore, in the image forming apparatus 10 according to the present embodiment, when printing in units of jobs is performed, an image in units of sections (hereinafter referred to as “partition images”) formed by dividing an image formed on a document into a mesh shape. ”Is performed every time, and maintenance is performed based on the result of the failure diagnosis. More specifically, the print defect for each diagnosed section image is compared with the image of the original in section image units, and maintenance is performed only for the print defect corresponding to the section image that affects printing.

Furthermore, the printing failure is classified into a plurality of levels to which time until the next maintenance, which is different depending on the maintenance necessity (urgent level), is given. As a result, the precise maintenance timing is controlled, and as a result, excessive maintenance is suppressed.
The maintenance in the present embodiment includes, for example, wiping (wiping the ejection surface) of the nozzle 48a of the inkjet recording head 48 by a wiping device (not shown).

As described above, in the image forming apparatus 10 according to the present embodiment, a failure diagnosis is executed prior to printing. With reference to FIG. 6, the detection of a printing defect in the defect diagnosis (hereinafter referred to as “printing defect”).
A method (sometimes referred to as “defect detection”) will be described. In the present embodiment, there is no particular limitation on the specific failure content, but in the following description, a nozzle failure that is a failure of the nozzle 48a will be described as an example.

  As shown in FIG. 6A, in the defect detection according to the present embodiment, the document is divided into a plurality of segment images, and defect detection is executed for each segment image. In FIG. 6A, as an example, the image is divided into 9 3 × 3 divided images. Hereinafter, when each section corresponding to each section image (hereinafter, sometimes referred to as “image section”) is specified and referred to, the section number shown in FIG. Etc.).

Here, the nozzle failure includes a non-discharge failure in which ink droplets (droplets) cannot be discharged due to clogging of the nozzle 48a, a thin line failure in which the amount of ink droplet discharge decreases and the printed line becomes thin,
There is a landing position misalignment defect in which the position of the ink droplets ejected by a foreign matter or the like formed in the vicinity of the ejection port of the nozzle 48a is shifted (see FIG. 6C described later for details). These nozzle defects cause printing defects, and an urgency level is given according to the contents of the defects.

In order to detect each nozzle defect, in the defect detection according to the present embodiment, as an example,
A test pattern 302 shown in FIG. 6B and a test pattern 304 shown in FIG. 6D are used. The test patterns 302 and 304 may be stored in a storage unit such as the ROM 102. Hereinafter, the test patterns 302 and 304 may be collectively referred to as a test pattern 300.

  The test pattern 302 shown in FIG. 6B is a so-called ladder pattern, and is a pattern printed on the recording paper P by the nozzle 48a as follows.

  That is, the nozzles 48a-1 to 48a-N of the ink jet recording head 48 shown in FIG. 2 are selected every predetermined number (three in the present embodiment) and simultaneously extend in the transport direction of the recording paper P. A straight line is printed (portion of position number 1 in FIG. 2). Next, the nozzle 48a is shifted by one and selected every predetermined number, and at the same time, a straight line extending in the conveyance direction of the recording paper P is printed (portion number 2 in FIG. 2). The nozzle 48a is again shifted by one and selected every predetermined number, and at the same time, a straight line extending in the conveyance direction of the recording paper P is printed (portion number 3 in FIG. 2). As described above, a pattern printed in a plurality of lines (three lines in the present embodiment) in the transport direction is a ladder pattern.

  [1] to [4] in FIG. 6C are partial enlarged views of the print result of the test pattern 302 corresponding to each nozzle defect mode.

  FIG. 6C [1] shows a case where the discharge of the nozzle 48a is normal. When some abnormality occurs in the nozzle 48a and normal printing cannot be performed, each line segment printed according to the abnormal state of the nozzle 48a deviates from the normal printing pattern.

FIG. 6 (c) [2] is an example of a case where ink droplets cannot be ejected from the nozzle 48a for some reason (undischarge failure), and the line at the position corresponding to the nozzle 48a where the failure has occurred. Minute print is missing.
FIG. 6C [3] is an example of a case where the ejection amount of ink droplets from the nozzle 48a is reduced for some reason (thin line defect), and printing is performed at a position corresponding to the nozzle 48a where the defect has occurred. The line segment is thin.
FIGS. 6C and 4 are examples of the case where the ink droplet ejected from the nozzle 48a is bent due to some cause (defect landing position deviation), and the position corresponding to the nozzle 48a where the defect has occurred. The line segment is inclined at.

  A portion indicated by N in the test pattern 302 in FIG. 6B shows a case where a discharge failure has occurred as an example of the failure detection.

  On the other hand, the test pattern 304 shown in FIG. 6D is a so-called solid pattern printed at a predetermined printing density (ratio of the printed area in the recording paper P). In the test pattern 304, for example, when a discharge failure occurs in the nozzle 48a, a white stripe S may occur in a portion corresponding to the nozzle in the printed test pattern 304 as shown in FIG. Alternatively, when the landing position deviation defect occurs in the nozzle 48a, the density of the portion corresponding to the nozzle 48a becomes high, and so-called black streaks may occur. The test pattern 304 is a test pattern for detecting a nozzle failure using these stripes.

  There is no particular limitation on the form of the test pattern 300 according to the present embodiment. For example, the test patterns 302 and 304 may be created by combining the relations with the image sections. For example, the test patterns 302 and 304 may be individually printed on the recording paper P, or the test patterns 302 and 304 may be mixed and printed on one page of the recording paper P.

  Further, the defective nozzles corresponding to the image sections are detected by dividing the section in the width direction of the printable area of the recording paper P (hereinafter sometimes referred to as “print area”) into the divided nozzles 48-1 to 48 described above. In correspondence with -M, each divided nozzle may be driven individually.

Next, with reference to FIG. 7, the defect level which is an index indicating the urgency of the defect according to the present embodiment will be described. FIG. 7 is a defect level table according to the present embodiment.
In the present embodiment, when a failure diagnosis is performed by the method described above, a level of urgency is given according to the diagnosed failure content. In other words, the defect content is generally a defect content that requires immediate maintenance, and does not require immediate maintenance at present, but only requires re-diagnosis after a predetermined period of time based on past experience, data, etc. There is a wide range of defective contents that are judged good.

The image forming apparatus 10 according to the present embodiment pays attention to this point, and classifies the failure content into a plurality of levels to which time until the next maintenance or failure diagnosis (re-diagnosis) is given according to the degree of the failure content. To set the defect level. Then, the time until the next maintenance or failure diagnosis is set by determining the failure level based on the result of the failure diagnosis.
As a result, since the time until maintenance or failure diagnosis is delayed based on the failure level that is finely classified, excessive maintenance is suppressed.

In FIG. 7, the defect levels according to the present embodiment are classified into, for example, six levels of LvA, LvB, LvC, LvD, LvE, and LvF in descending order of urgency. In addition, the contents of each defect level, that is, the time until the delayed maintenance or defect diagnosis (permissible execution time) is as follows.
LvA: Repair, replacement or manual maintenance is required LvB: Maintenance is required immediately LvC: Maintenance is required for each job LvD: Maintenance is required after 12 hours at the latest LvE: Negligible defects are recognized, but re-diagnosis is performed after 24 hours at the latest Necessary LvF: Defects are not recognized, but rediagnosis is required after 24 hours at the latest. Of course, the level of the defect level is not limited to 6, and may be 5 levels or less, or 7 levels or more.

  Here, the time of 12 hours or 24 hours assigned to the defect level is an example, and may be changed according to the specific contents of the defect level (for example, the difference in the number of defective nozzles described later). Further, for example, even for the same LvD, for example, the time until maintenance may be changed according to the number of defective nozzles.

  The defect level LvA is a defect level that requires immediate repair, replacement, or manual maintenance via the operator.

The defect level LvB is a defect level at which automatic maintenance needs to be performed immediately.
When the defect level is LvB, maintenance is performed at a timing instructed in an image forming processing program to be described later.

  The defect level LvC is not a level that requires immediate maintenance, but is a defect level that requires automatic maintenance each time a job is executed. When the defect level is LvC, maintenance is performed at a timing instructed in an image forming processing program to be described later.

  The defect level LvD is a defect level in which a defect is recognized and maintenance needs to be performed after 12 hours at the latest. That is, it is not necessary to perform maintenance immediately, and as a result, the time until the maintenance is performed is delayed for 12 hours. In LvD, the time until the next maintenance (in this embodiment, 12 hours) is associated and stored. When the defect level is LvD, maintenance is performed at a timing instructed in an image forming processing program described later.

  The defect level LvE is a defect level that can be determined by performing a defect diagnosis (re-diagnosis) again after 24 hours although a defect is recognized. Since it is a minor defect, maintenance is not performed, and as a result, the time until the maintenance is performed is delayed. In LvE, the time until the next failure diagnosis (24 hours in the present embodiment) is associated and stored. When the defect level is LvE, the defect diagnosis is performed at a timing instructed in an image forming processing program described later.

  The defect level LvF is a defect level at which no current defect is recognized. However, in this case also, as an example, the failure diagnosis (re-diagnosis) is performed again after 24 hours. In LvF, the time until the next failure diagnosis (24 hours in this example) is associated and stored. When the defect level is LvF, defect diagnosis is performed at a timing instructed in an image forming processing program described later.

  In the present embodiment, the time until the next maintenance or failure diagnosis is stored in place of the time at which maintenance or failure diagnosis is to be executed (hereinafter sometimes referred to as “target time”). For example, if the time when the result of the failure diagnosis is obtained by LvD is 10 am, the maintenance target time is 10 pm, 12 hours later.

Furthermore, as shown in FIG. 7, each defect level is defined in association with a criterion for classification into each defect level. In the present invention, there is no limitation on the index of the determination criterion for each defect level and the threshold value of the index. However, in the present embodiment, the number of defective nozzles (hereinafter referred to as “the number of defective nozzles” may be used as the criterion criterion). Adopt). And
As shown in FIG. 7, as an example, the thresholds of the number of defective nozzles corresponding to each defect level are 100 or more for LvA, 50 or more for LvB (50 or more and less than 100), and 30 or more for LvC ( 30 or more, less than 50), LvD is 20 or more (20 or more, less than 30), LvE is 5 or more (5 or more, less than 20), and LvF is 0 (less than 5) It has become.

  In the flag shown in FIG. 7, 0 indicates that the target time for maintenance or failure diagnosis is invalid (the target time is not set), and 1 indicates that the target time for maintenance or failure diagnosis is valid. (Target time is set). This flag may be used when determining whether or not the target time is set in an image forming processing program described later.

  Next, with reference to FIG. 8, an example of a failure diagnosis result indicating a result of failure diagnosis according to the present embodiment will be described. The defect diagnosis according to the present embodiment is performed for each image section, the defect level is determined for each image section, and the defect diagnosis result is created. The defect diagnosis result is used when determining the necessity of maintenance or defect diagnosis for each image section in an image forming processing program to be described later.

In the example of FIG. 8, a failure diagnosis result having the following contents is shown.
1st section: LvF, 2nd section: LvF, 3rd section: LvC, 4th section: LvF, 5th section: LvF, 6th section: LvC, 7th section: LvB, 8th section: LvF, 9th Section: LvC
In other words, the image section in the right column of the print area of the document has an LvC defect level, and the lower left image section has an LvB defect level.

Next, update of the failure diagnosis result will be described with reference to FIG. In the failure diagnosis according to the present embodiment, every time failure diagnosis is executed, the failure diagnosis result of the failure diagnosis is stored in storage means such as the storage unit 110 (NVM 106). Then, when the next failure diagnosis is performed, the previous failure diagnosis result is updated. In FIG. 9, FIG. 9A shows the previous failure diagnosis result, and FIG. 9B shows the execution of the current failure diagnosis. The result is shown, and FIG. 9 (c) shows the updated latest failure diagnosis result.

  Although there is no particular restriction on the method (algorithm) for updating the failure diagnosis result, in this embodiment, the previous failure level is compared with the previous failure level for each image section, and the failure level with a higher urgency is updated. As a level, the failure diagnosis result is updated.

That is, when the previous failure diagnosis result in FIG. 9A is compared with the current failure diagnosis execution result in FIG. 9B, the image sections that affect the failure diagnosis result in FIG. , Third, sixth, and ninth image sections.
Therefore, the latest failure diagnosis result is as shown in FIG.

Note that the symbols “×” and “→” in FIG. 9 are expressed in the form of A × B → C.
This indicates that a predetermined calculation process is performed between A and B and calculation result C of the calculation process is obtained. The arithmetic processing according to the present embodiment refers to the above algorithm, for example. The same applies to the symbols “×” and “→” in the following.

  FIG. 10 shows the above algorithm in a matrix. In FIG. 10, the defect levels LvA to LvF displayed in the vertical (column) headings indicate the previous failure diagnosis results, and the defect levels LvA to LvF displayed in the horizontal (row) headings are the execution of the current defect diagnosis. Results are shown.

In FIG. 10, for example, when the previous failure diagnosis result is LvC and the current failure diagnosis execution result is LvD, the failure level of the latest failure diagnosis result is LvC from the failure level LvC in the cell where they intersect. (Corresponding to the third section in the above example).
Also, if the previous failure diagnosis result is LvD and the current failure diagnosis execution result is LvC,
From the failure level LvC in the cell where they intersect, the failure level of the latest failure diagnosis result is LvC (corresponding to the sixth section in the above example).
Furthermore, when the previous failure diagnosis result is LvE and the current failure diagnosis execution result is LvC, the failure level of the latest failure diagnosis result is LvC from the failure level LvC in the cell where they intersect (see above). Corresponds to the ninth section of the example).

T0 displayed in the column heading of FIG. 10 is the target time in the previous failure diagnosis result,
T1 displayed in the heading of the row is a target time in the result of the current failure diagnosis. The min (t0, t1) displayed in the cell is the smaller of t0 and t1, that is, the earlier time of the previous target time and the current target time, which is the latest failure diagnosis result. This indicates that the data is stored in association with the defect level.

  Next, with reference to FIG. 11, a failure diagnosis result in a state in which all the printing defects indicated by the defect levels of the respective image sections have been eliminated by executing the maintenance will be described.

FIG. 11A shows a previous failure diagnosis result, and FIG. 11B shows a case where maintenance is performed after obtaining the previous failure diagnosis result, and printing defects in all image sections are resolved by subsequent updates. This shows the latest failure diagnosis result, which is the failure diagnosis result. As shown in FIG.
In the present embodiment, when the printing defect of all the image sections is eliminated, the defect level of all the image sections is set to LvF. In the following, it may be referred to as “reset” that all printing defects are eliminated by maintenance and this failure diagnosis result is obtained.

Next, with reference to FIG. 12 to FIG. 15, the relationship between an image of a document and the failure diagnosis result will be described.
In the image forming apparatus 10 according to the present embodiment, in order to more effectively suppress the maintenance execution frequency, in addition to the above-described defect diagnosis, an image of a document or the like and a defect diagnosis result are compared for each image section, If the diagnosed defective content does not actually affect the printing of the manuscript or the like, a process for delaying the execution time is performed without immediately performing maintenance. In the following, comparing the image of a document or the like with the result of defect diagnosis and extracting the details of the defect that actually affects printing will be referred to as “defect determination” and affect the actual print defect obtained as a result of the defect determination. An image section may be referred to as an “overlapping section”.

  The “overlapping section” is defined as an image section in which an image such as an original exists and an image section in which a defect is recognized as a result of the defect determination. However, in this embodiment, since a defect level is always assigned to all image sections as a result of the defect diagnosis (at least the defect level LvF is assigned), the overlapping section is an image section where an image such as a document actually exists. It becomes.

12A shows a print image of a document or the like in the print job, FIG. 12B shows the latest failure diagnosis result upon execution of the print job, and FIG. 12C shows the overlapping section (FIG. 12C ) Indicates “calculation result”). In the image forming apparatus 10 according to the present embodiment,
A printed image such as a document is divided into image sections similar to those in the case of defect diagnosis, and after determining whether or not an image exists in each image section, the result is compared with the result of defect diagnosis. Then, a defect level of an image section where an image such as a document is present is extracted, and a defect level with the highest urgency among the defect levels is referred to as a result of the defect determination (hereinafter may be referred to as a “defect determination result”). And

  FIG. 12C shows an example in which the second section, the fifth section, and the eighth section are determined to be overlapping sections as a result of comparing the printed image of a document or the like with the failure diagnosis result. Since the defect level of any overlapping section is LvF, it is a defect determination result that no defect is recognized (see also FIG. 7). That is, as shown in FIG. 12B, when the entire image section is viewed, there is a possibility of occurrence of a printing defect at a defect level of LvB (seventh section) or LvC (third section, sixth section, ninth section). In spite of the fact, it is determined that the occurrence of defective printing is not actually predicted in relation to the document or the like. Therefore, the maintenance period is delayed.

In the above-described defect determination, “1” is assigned to an image section where an image such as a document exists,
A non-existing image section is assigned “0”, and an image of a document or the like to which 1 or 0 is added and a defect level in a defect diagnosis result are calculated for each image section to determine a defect level for each overlapping section. May be.

Next, an example of a failure determination result when it is determined that maintenance is necessary will be described with reference to FIG.
FIG. 13A shows a print image of a document or the like in a print job, FIG. 13B shows the latest failure diagnosis result, and FIG. 13C shows an overlap section (“calculation result” in FIG. 13C). Notation). FIG. 13B illustrates the case of the same failure diagnosis result as in FIG.

  In the example of FIG. 13, when the printed image of a manuscript or the like is compared with the failure diagnosis result, the first section to the eighth section are overlapped sections. And since the defect level with the highest urgent level is LvB among the defect levels of each of the first section to the eighth section, the defect determination result is LvB. Therefore, compared with FIG. 12, the failure diagnosis result is the same. However, although it is determined that no defect is recognized in FIG. Determined.

Next, defect determination when a document or the like is composed of a plurality of pages will be described with reference to FIG.
FIG. 14 (a) shows a document composed of two pages, FIG. 14 (b) shows the latest failure diagnosis result, and FIG. 14 (c) shows an overlapping section (“calculation result” in FIG. 14 (c)). Notation). FIG. 14B illustrates a case where the same failure diagnosis result as in FIG.

  In this case, as shown in FIG. 14C, defect determination is performed by first obtaining a logical sum for each image section of each page such as a document, and extracting image sections where print images exist for all pages to obtain overlapping sections. The failure level having the highest urgency among the failure levels corresponding to the overlapping sections of the failure diagnosis result is set as the failure determination result. However, in calculating the logical sum, it is assumed that “1” is assigned to an image section where an image is present and “0” is assigned to a section where no image is present.

  The defect determination result in the example of FIG. 14 is LvC as shown in FIG. In the case of the example of FIG. 14, the defect level as a whole of the defect diagnosis result is LvB (seventh section, immediate maintenance is required), but in the case of the example of FIG. Since there is no image such as a document in the seventh section), it is determined as LvC (maintenance is required for each job).

  In the above embodiment, first, the logical sum for each image section of the print image of each page is obtained to extract the overlapping section where the print image exists, and the highest urgent level among the extracted defective levels of the overlapping section. Although the defect level is defined as the defect determination result, the present invention is not limited to this. For example, the result is the same even when the defect determination result of each page is obtained from the print image of each page and the defect diagnosis result, and a defect level with a high degree of urgency is extracted from the result to obtain the overall defect determination result.

  Next, defect determination when the print job is color printing will be described with reference to FIG. 15A shows a print image for each page of a document or the like in the print job, FIG. 15B shows the latest failure diagnosis result for each color, and FIG. 15C shows an overlapping section for each color (FIG. 15). (C) indicates “calculation result”).

  The print image shown in FIG. 15A exemplifies a case where the printed region for each color is different in a document or the like. That is, cyan (C) is in the second quadrant when the print area of the original is divided into four, magenta (M) is in the first quadrant, yellow (Y) is in the third quadrant, and black (K) is Printed in the fourth quadrant.

  On the other hand, the failure diagnosis result shown in FIG. 15B is different for each color. As shown in FIG. 1, the head unit 46 according to the present embodiment has four ink jet recordings corresponding to four colors of yellow (Y), magenta (M), cyan (C), and black (K). Since the head 48 is provided, the failure diagnosis result also differs for each color. This means that the maintenance target may be different for each color.

As pre-processing for defect determination, first, the operation result for each color, that is, an image such as a document for each color is compared with the failure diagnosis result for each color, and an overlapping section is extracted. A high defect level is determined as the defect level of the color (that is, the defect determination result of the color). For example, for magenta (M), as shown in FIG. 15C, the overlapping sections of the magenta (M) image and the magenta (M) failure diagnosis result are the second section, the third section, the fifth section, And it becomes the 6th division. The defect level of each section is LvC in the second section, LvF in the third section, LvC in the fifth section, and LvF in the sixth section, so that the magenta (M) defect determination result is LvC. It is.
Similarly, the defect determination result for cyan (C) is LvF, the defect determination result for yellow (Y) is LvB, and the defect determination result for black (K) is LvC.

  Next, the defect determination result with the highest degree of urgency among the defect determination results for each color is set as the defect determination result for the print job. According to this method, the failure determination result in the example of FIG. 15 is LvB.

  In the present embodiment, an example in which the failure diagnosis result stored in the storage unit such as the storage unit 110 (NVM 106) is updated has been described, but the present invention is not limited to this. The file name of the failure diagnosis result may be, for example, a file name including the date on which the failure diagnosis is performed, and may be stored in a storage unit such as the storage unit 110 (NVM 106) as a separate file for each update to leave a history. In this case, the previous failure diagnosis result is determined by the date of the file name.

  Next, an image forming process executed by the image forming apparatus 10 according to the present embodiment will be described with reference to FIGS. FIG. 16 is a flowchart showing a process flow of an image forming process program executed by the CPU 100, and FIGS. 17 to 20 are flowcharts showing a process flow of each subroutine. The program is stored in storage means such as a predetermined area in the ROM 102, for example. The image forming processing program is a program for performing printing processing while performing maintenance and defect diagnosis when necessary.

  Here, the execution of the image forming processing program is not limited to a form in which the program is preinstalled in the ROM 102 or the like, but a form provided in a state stored in a computer-readable storage medium, wired or wireless The form distributed via the communication means by the above may be applied.

  Further, the image forming process according to the present embodiment is realized by a software configuration using a computer by executing a program. However, the configuration is not limited to the software configuration, and may be realized by, for example, a hardware configuration employing ASIC (Application Specific Integrated Circuit) or a combination of the hardware configuration and the software configuration.

  In the image forming process according to the present embodiment, an operator places a document on a document table (not shown) of the scanner unit 120, designates the number of prints from the UI panel 108 or the like, and instructs the start of printing. This is done by the CPU 100 reading and executing the image forming processing program from the ROM 102 or the like. Here, it is assumed that the manuscript is placed on the manuscript table and an instruction to start printing is given.

As shown in FIG. 16, first, in step S100, the scanner unit 120 waits until image information of a document image is generated (see also FIG. 4).
In the next step S102, the image information of the generated document image is converted into a print image by the same processing as the image processing unit 100A described above.

In the next step S104, a failure diagnosis / maintenance processing subroutine (FIG. 17) is executed.
In the next step S106, it is determined whether or not the failure determination result of the failure diagnosis / maintenance processing subroutine is LvA.
If the determination in step S106 is affirmative, the process proceeds to step S114, the UI panel 108 is controlled to display that repair, replacement, or manual maintenance is necessary, and the image forming processing program is terminated.

On the other hand, if a negative determination is made in step S106, the process proceeds to step S108, and a print processing subroutine (FIG. 20) is executed.
In the next step S110, it is determined whether or not an interruption has occurred in the printing process in step S108. The interruption occurs, for example, when the paper is jammed inside the image forming apparatus 10 or when there are no more ink droplets to be supplied to the inkjet recording head 48.

  If the determination in step S110 is affirmative, the control value for the interrupted print job is adjusted in preparation for resuming the print job in step S112, and the process returns to step S104.

  On the other hand, if a negative determination is made in step S110, the process proceeds to step S116, the job that has been printed is erased from the storage means such as the RAM 104, and the process returns to step S100 to enter a standby state for generating the next document image. .

  Next, a failure diagnosis / maintenance processing subroutine called by the image forming processing program (FIG. 16) will be described with reference to FIG. This subroutine is a subroutine for determining a defect determination result from a printed image of a document or the like and a defect diagnosis result, and executing necessary maintenance and defect diagnosis based on the defect determination result.

First, in step S200, 0 is substituted into a variable i which is a counter of the number of times the maintenance processing subroutine (step S224) is called.
In the next step S202, a logical sum is calculated for the print images of all pages in the print job (see also FIG. 14).

In the next step S204, the logical product of the logical sum of the print images obtained in step S202 and the failure diagnosis result is calculated, that is, the failure level of the failure diagnosis result existing in the overlapping section is extracted.
Here, the failure diagnosis result is the latest failure diagnosis result that has been implemented in the image forming process of the previous print job and stored in the storage unit such as the storage unit 110 (NVM 106).
Note that, as the failure diagnosis result when the failure diagnosis / maintenance processing subroutine is first executed, a failure diagnosis result prepared in advance (for example, a reset failure diagnosis result) is used.

In the next step S206, the failure level with the highest urgency among the failure levels of the overlapping sections obtained in step S204 is determined as the current failure determination result.
In the next step S208, it is determined whether or not the defect level of the defect determination result determined in step S206 is LvA.

If the determination in step S208 is affirmative, the process returns to the image forming process program (indicated as “return” in FIG. 17, the same applies hereinafter). When the defect determination result is LvA, repair, replacement, or manual maintenance is required (see also FIG. 7), so the following process returns to the image forming processing program without performing maintenance or defect diagnosis.
On the other hand, if a negative determination is made in step S208, the process proceeds to step S210, and it is determined whether or not the defect level of the defect determination result determined in step S206 is LvB.

If the determination in step S210 is affirmative, the process proceeds to step S212 to determine whether or not the counter i is the upper limit value N.
If the determination in step S212 is affirmative, the process proceeds to step S214, the defect determination result is changed to LvA, and the process returns to the image forming processing program.

  Here, the upper limit value of the counter i is a value that determines that the process does not converge when the maintenance process subroutine (step S224) is passed a certain number of times, and performs the process of exiting from the failure diagnosis / maintenance process subroutine. . That is, this error diagnosis / maintenance processing subroutine is an error process for preventing the subroutine from falling into an infinite loop. When the subroutine is exited, the failure determination result is set to the failure level LvA having the highest degree of urgency in anticipation of safety.

  On the other hand, if a negative determination is made in step 212, the process proceeds to step S224, and maintenance processing is executed. This is because when the defect level is LvB, maintenance processing is required immediately (see also FIG. 7).

If a negative determination is made in step S210, the process proceeds to step S216, and it is determined whether or not the defect level of the defect determination result determined in step S206 is LvC.
If the determination in step S216 is affirmative, the process proceeds to step S218 to determine whether or not the counter i is 1. In step S218, it is determined whether or not the maintenance process is performed at least once in the defect diagnosis / maintenance process subroutine.

  If the determination in step S218 is affirmative, that is, if it is determined that the maintenance process has been performed once in the past, the process returns to the image forming process program. On the other hand, when a negative determination is made, that is, when it is determined that the maintenance process has not been performed once, the process proceeds to step S224 and the maintenance process is executed. This is because when the defect level is LvC, maintenance processing is required for each job (see also FIG. 7).

On the other hand, if a negative determination is made in step S216, the process proceeds to step S220, and it is determined whether or not the defect level of the defect determination result determined in step S206 is LvD.
If the determination in step S220 is negative, the process proceeds to step S228. If the determination is affirmative, the process proceeds to step S222 to determine whether the target time has arrived. This is because when the defect level is LvD, maintenance processing is required after 12 hours at the latest (see also FIG. 7).

  The target time in step S222 is the target time given to the defect level LvD in the overlapping section obtained in step S204, and is the earliest target time when there are a plurality of LvDs.

If the determination in step S222 is negative, the process proceeds to step S228. If the determination is affirmative, the process proceeds to step S224 to execute a maintenance processing subroutine.
After the counter i is incremented by 1 in the next step S226, a failure diagnosis processing subroutine is executed in the next step S230.

In step S228, it is determined whether or not the earliest target time has arrived among the target times assigned to the defect levels LvE or LvF in the overlapping section.
If a negative determination is made in step S228, the process returns to the image forming process program. If an affirmative determination is made, the process proceeds to step S230 to execute a failure diagnosis processing subroutine, and then returns to step S204. By this failure diagnosis processing subroutine, the failure diagnosis result is updated to obtain the latest failure diagnosis result.

Here, in the failure diagnosis / maintenance processing subroutine according to the present embodiment, after the maintenance processing is executed in step S224, the failure diagnosis processing is always executed in step S230 to confirm the effect of the maintenance.
After executing the failure diagnosis process in step S230, the process returns to step S204, and the following process is performed reflecting the latest failure diagnosis result to determine the necessity of maintenance.

Next, a maintenance processing subroutine called in the failure diagnosis / maintenance processing subroutine will be described with reference to FIG.
First, in step S300, the corresponding part is controlled so that maintenance is performed. More specifically, for example, in the case of wiping the nozzle 48a of the inkjet recording head 48, a wiping device (not shown) is controlled so that the nozzle 48a is wiped.
In the next step S302, the process waits until the maintenance is completed.

  In the next step S304, all image sections of the failure diagnosis result are set to LvF to which the next failure diagnosis target time is given (see also FIG. 7. In the example of FIG. 7, 24 hours after the current time is set. The target time is determined.), The process returns to the failure diagnosis / maintenance processing subroutine. That is, in step S304, in response to the completion of the maintenance in step S302, the failure diagnosis result is reset.

Next, a failure diagnosis processing subroutine called in the failure diagnosis / maintenance processing subroutine will be described with reference to FIG.
First, in step S400, image information of the test pattern 300 is read from the ROM 102 or the like.

  In the next step S402, based on the image information of the test pattern 300 read in step S400, the recording head controller 116, the motor controller 118, etc. are controlled so that the test pattern 300 is printed. As a result, the necessary number of sheets are supplied from the sheet feeding / conveying section 12, the supplied sheets are conveyed in the sheet conveying path, and the conveyance of the sheets is stopped when all the supplied sheets are discharged to the discharging section 22. Is performed. A test pattern 300 is printed on a sheet in the middle of conveyance by the image forming unit 16 to obtain a test pattern print (see also FIG. 5).

  In the next step S404, the inline sensor 80 is controlled so that a printed image of the test pattern 300 is generated. As a result, the printed material of the test pattern is read by the in-line sensor 80 during the conveyance, and a printed image of the test pattern is generated.

In the next step S406, the process waits until the sheet conveyed in step S402 stops at a predetermined position.
In the next step S408, the printed image of the test pattern 300 generated in step S404 is captured from the inline sensor 80.

  In the next step S410, the image information of the test pattern read in step S400 is compared with the image information of the printed image of the test pattern captured in step S408, and the difference between both is extracted.

In the next step S412, the defect levels of all image sections are determined based on the difference extracted in step S410.
More specifically, the number of defective nozzles for each image section is calculated from the difference between the image information of the test pattern and the printed pattern image information of the test pattern, and the defect level table of FIG. Determine the defect level.

In the next step S414, a target time based on the current time is set and assigned to each defect level determined for each image section determined in step S412.
In the next step S416, a failure diagnosis execution result is created by associating the failure level determined in step S412 with the target time given in step S414.

In the next step S418, the previous failure diagnosis result and the current failure diagnosis execution result are compared to update the failure diagnosis result to the latest failure diagnosis result, and return to the failure diagnosis / maintenance processing subroutine.
That is, the previous defect diagnosis result and the current defect diagnosis execution result are compared for each image section, and the defect level with the higher urgency is set as the defect level of the image section. Also,
The target time is compared for each image section. If only one target time is valid, the target time is given. If both target times are valid, the earlier time is given.

Next, a print processing subroutine called by the image forming processing program will be described with reference to FIG.
First, in step S500, the print head controller 116, the motor controller 118, and the like are controlled so that the print target job is printed. As a result, the necessary number of sheets are supplied from the sheet feeding / conveying section 12, the supplied sheets are conveyed in the sheet conveying path, and the conveyance of the sheets is stopped when all the supplied sheets are discharged to the discharging section 22. Is performed.

In the next step S502, it is determined whether or not the conveyance of the sheet is stopped.
If the determination in step S502 is affirmative, the process proceeds to step S504. If the determination is negative, the process proceeds to step S510 to determine whether the target time has arrived. The target time here is the earliest target time among a plurality of LvD, LvE, and LvF in the overlapping section of the failure diagnosis result determined in step S204 of the failure diagnosis / maintenance processing subroutine (FIG. 17).

  If the determination in step S510 is negative, the process returns to step S502. If the determination is affirmative, the process proceeds to step S512, printing is interrupted, and the process returns to the image forming process program. The interruption is performed, for example, by stopping the supply of paper from the paper feeding / conveying unit 12.

  In step S504, it is determined whether printing has been completed. For example, whether or not the printing is completed is determined by performing printing on the number of sheets set by the operator via the UI panel 108 or the like, and discharging the necessary number of sheets in the discharge unit 22. It may be determined based on whether or not it is done.

  If the determination in step S504 is affirmative, the process returns to the image forming processing program. If the determination is negative, the process proceeds to step S506, and the UI panel 108 and the like are controlled so as to display an instruction to cancel interruption. . In the display on the UI panel 108 and the like at this time, for example, the cause of interruption, the cancellation method of interruption, and the like may be displayed together with the message “print interruption has occurred”.

  In the next step S508, the process waits until the interruption is canceled by the operator, and then returns to the image forming processing program. Step S508 is executed, for example, when the operator takes a measure for the cause of the interruption (for example, removes the jammed paper) and inputs that the measure has been taken via the UI panel 108 or the like.

  As described above in detail, according to the image forming apparatus according to the present embodiment, excessive maintenance for image formation defects is suppressed.

Here, in the above-described embodiment, an example has been described in which the elapsed time is used to define the timing for performing the next maintenance or failure diagnosis. However, the present invention is not limited to this. For example,
You may prescribe | regulate by the total number of sheets (sheet passing number) of the recording paper P printed from the predetermined time (for example, the time of reset mentioned above) to the time.

In the form in which the number of sheets to be passed is used to define the timing for performing the next maintenance or defect diagnosis, the contents of the defect levels LvD, LvE, and LvF in FIG. 7 may be as follows, for example.
LvD: Maintenance is required after printing 10,000 sheets at the latest.
LvE: Negligible defects are recognized, but re-diagnosis is necessary after printing 100,000 sheets at the latest.
LvF: Defects are not recognized, but re-diagnosis is necessary after printing 100,000 sheets at the latest.
In this case, for example, if it is assumed that the defect level is LvD and the current number of sheets to be passed is 500,000, the target number of sheets to be passed until the next maintenance or failure diagnosis timing is 510,000.

  The timing for performing the next maintenance or defect diagnosis may be determined by combining the elapsed time and the number of sheets to be passed. For example, the defect level LvD may be determined by the number of sheets passed, and the defect levels LvE and LvF may be determined by the elapsed time.

  In the above-described embodiment, the present invention has been described by exemplifying a mode in which the present invention is applied to an ink jet type image forming apparatus. However, the present invention is not limited to this.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Paper feed conveyance part 14 Processing liquid application part 16 Image formation part 18 Drying part 20 Image fixing part 22 Discharge part 24 Discharge conveyance part 26 Accommodating part 28A thru | or 28E Intermediate conveyance drum 30 Motor 32 Belt 34 Holding member 36 Processing Liquid coating drum 38 Processing liquid coating roller 44 Image forming drum 46 Head unit 48 Inkjet recording heads 48-1 to 48-M Split head 48a Nozzle 56 Ink drying drum 58 Hot air heater 62 Image fixing drum 64 Fixing roller 68 Discharge transport drum 80 Inline sensor 100 CPU
100A Image processing unit 100B Image comparison unit 102 ROM
104 RAM
106 NVM
108 UI Panel 110 Storage Unit 116 Recording Head Controller 118 Motor Controller 120 Scanner Unit 300, 302, 304 Test Pattern BUS Bus P Recording Paper S Line

Claims (6)

Forming means for forming an image on a recording medium;
Reading means for reading a formed image that is an image formed on the recording medium by the forming means;
Degree of defect indicating the degree of defect in the forming means for each predetermined stage, and an allowable execution time that is an allowable period for performing maintenance or rediagnosis for the defect for each stage of the defect degree. Storage means stored in advance;
First image information used for forming an image by the forming unit and second image information obtained by reading the formed image by forming the image by the reading unit are set for each predetermined segment area. Based on the result of comparison, diagnostic means for diagnosing the degree of failure for each segmented area,
When an image of a predetermined document is formed by the forming unit, based on document image information indicating the image of the document, the divided area including the image formed on the recording medium by the forming unit Deriving means for deriving the highest degree of the degree of defect obtained by the diagnostic means as the overall degree of defect of the document image;
Executing means for executing the maintenance and predetermined processing for performing at least one of the re-diagnosis in the allowable implementation time Kemah corresponding to the order of defective derived by the deriving means,
An image forming apparatus. The derivation unit is configured to target all image forming regions based on the images of the plurality of documents when continuously forming images of a plurality of documents in which at least a part of the region where the image is formed by the forming unit is different from each other. The image forming apparatus according to claim 1 , wherein the overall degree of the defect is derived. The execution means, when said maintenance executing a predetermined processing for, according to claim 1 or claim 2 to perform the predetermined processing for the re-diagnosis subsequent to the process Image forming apparatus. The allowable execution time includes an elapsed time allowed as a time for performing at least one of maintenance and rediagnosis for the defect, the allowable time, and the number of images formed on the recording medium by the allowable forming unit. the image forming apparatus according to any one of the least is one claims 1 to 3. It said forming means, the image forming apparatus according to any one of claims 1 to 4 to form an image by an electrophotographic method or an inkjet method. Forming means for forming an image on a recording medium;
Reading means for reading a formed image that is an image formed on the recording medium by the forming means;
Degree of defect indicating the degree of defect in the forming means for each predetermined stage, and an allowable execution time that is an allowable period for performing maintenance or rediagnosis for the defect for each stage of the defect degree. Storage means stored in advance;
A program for controlling an image forming apparatus including:
Computer
First image information used for forming an image by the forming unit and second image information obtained by reading the formed image by forming the image by the reading unit are set for each predetermined segment area. Based on the result of comparison, diagnostic means for diagnosing the degree of failure for each segmented area,
When an image of a predetermined document is formed by the forming unit, based on document image information indicating the image of the document, the divided area including the image formed on the recording medium by the forming unit Deriving means for deriving the highest degree of the degree of defect obtained by the diagnostic means as the overall degree of defect of the document image;
Executing means for executing the maintenance and predetermined processing for performing at least one of the re-diagnosis in the allowable implementation time Kemah corresponding to the order of defective derived by the deriving means,
Program to function as.