JP6102542B2 - Image forming apparatus and job management system - Google Patents

Description

  The present invention relates to an image forming apparatus and a job management system.

  In recent years, image forming apparatuses such as electrophotographic copying machines and printers have become widespread. In such an image forming apparatus, when the paper passes through the fixing device, the surface of the fixing roller is easily damaged at the end in the width direction of the paper, and the image defect is caused by the damage. The flaw on the fixing roller is a main cause of replacement of the fixing roller and has a great influence on the parts cost.

In particular, in production printing, there are many opportunities to print a large amount on the same type of paper, and a specific location of the fixing roller is easily damaged.
In production printing, since there is a high demand for image quality, it is necessary to know when to replace consumables such as a fixing roller in order to maintain image quality.

  For example, a method has been proposed in which whether or not a coating portion formed of an insulating material on the surface of a heat roller (fixing roller) in a heat fixing device is scratched is determined by a current-carrying state (Patent Document 1). reference).

  In addition, the wear amount of the fixing belt in the area to be passed at the edge of the paper is predicted from the paper size, paper type, and number of sheets to be passed, and the wear amount for each area divided in the width direction of the fixing belt is a threshold value. There has been proposed an image forming apparatus that determines that the life of the fixing belt is exceeded when exceeding the above (see Patent Document 2).

Japanese Patent Laid-Open No. 4-125580 JP 2012-53332 A

  However, the technique described in Patent Document 1 cannot determine which area in the longitudinal direction of the fixing roller is damaged. Therefore, when a flaw is detected from the fixing roller, it is necessary to replace the fixing roller even if there is no problem in other places. For example, when an image can be formed without using an area with a flaw on the fixing roller, or when an image (characters, etc.) that is not affected by the damage to the fusing roller is formed, a specific area on the fixing roller is flawed. In some cases, the fixing roller can continue to be used even when the toner exists.

  In addition, the technique described in Patent Document 2 merely predicts that the region through which the end of the paper passes wears, and it is unknown how much the fixing roller is actually damaged.

  The present invention has been made in view of the above problems in the prior art, and an object of the present invention is to grasp the damage of the fixing roller for each position in the longitudinal direction of the fixing roller.

  In order to solve the above-described problem, the invention according to claim 1 is an image forming apparatus including a fixing roller and a pressing roller pressed against the fixing roller, and the length of the fixing roller is Storage means for associating and storing the position in the direction and the degree of damage, acquisition means for acquiring the position through which the end of the paper passes in the longitudinal direction of the fixing roller, and the paper when the paper passes through the fixing device The displacement measuring means for measuring the displacement of the pressing roller in the direction facing the fixing roller, and the value based on the displacement measured by the displacement measuring means and the length in the transport direction of the paper passing through the fixing device are acquired. Control means for storing the degree of damage corresponding to the position acquired by the means in the storage means.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the degree of damage for each position stored in the storage unit is the displacement measured by the displacement measuring unit and the The value based on the length in the conveyance direction of the sheet that has passed through the fixing device is an accumulated value.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the control unit causes the display unit to display the degree of damage for each position stored in the storage unit.

  According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the control unit is any one of the degree of damage for each position stored in the storage unit. Printing is stopped when a predetermined threshold is reached.

  According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the control unit is any one of the degree of damage for each position stored in the storage unit. When the predetermined threshold value is reached, printing of the paper size that passes through the position where the degree of damage has reached the threshold value is stopped.

  According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the control unit is any one of the degree of damage for each position stored in the storage unit. When a predetermined threshold value is reached, if the position where the damage level reaches the threshold value is a non-image area or a character area, printing is performed, and the position where the damage level reaches the threshold value is a non-image area. If it is not an area or a character area, printing is stopped.

  According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the first to sixth aspects, the control unit has a predetermined degree of damage for each position stored in the storage unit. Based on the threshold and the print information requested to be printed, it is determined whether printing is possible, and the determination result is displayed on the display means.

  According to an eighth aspect of the present invention, in the image forming apparatus according to the seventh aspect, the threshold value is predetermined for each type of print information.

  According to a ninth aspect of the present invention, in the image forming apparatus according to any one of the first to eighth aspects, the control unit causes the displacement when the paper passes through the fixing device for each paper size. Based on the displacement measured by the measuring means and the length of the paper in the transport direction, the damage degree per sheet is calculated, and the calculated damage degree per sheet is stored in the storage means. Based on the degree of damage for each and a predetermined threshold, the number of printable sheets is calculated for each paper size, and the calculated number of printable sheets is displayed on the display means.

  According to a tenth aspect of the present invention, in the image forming apparatus according to any one of the first to eighth aspects, the control unit causes a sheet of a predetermined size to pass through the fixing device for each type of print information. The damage degree per sheet is calculated based on the displacement measured by the displacement measuring means and the length of the paper in the transport direction, and the calculated damage degree per sheet is stored in the storage means. The number of printable sheets is calculated for each type of print information based on the degree of damage for each position and the threshold value predetermined for each type of print information, and the calculated number of printable sheets is displayed on the display means. .

  According to an eleventh aspect of the present invention, in the image forming apparatus according to any one of the first to tenth aspects, a position stored in the storage unit with respect to an external device connected via a communication network. Transmitting means for transmitting the degree of damage for each is provided.

  A twelfth aspect of the present invention is the image forming apparatus according to any one of the fourth to tenth aspects, further comprising a changing unit that changes the threshold value.

  According to a thirteenth aspect of the present invention, in the image forming apparatus according to the twelfth aspect of the present invention, the image forming apparatus includes a receiving unit that receives an instruction to change the threshold value transmitted from an external device connected via a communication network. Changes the threshold based on the change instruction received by the receiving means.

  According to a fourteenth aspect of the present invention, in the image forming apparatus according to the twelfth aspect, the control unit prints an image for confirming the image quality on a sheet and confirms the image printed on the sheet. Operating means for receiving an instruction to change the threshold from the operating means, and the changing means changes the threshold based on the changing instruction received by the operating means.

  According to a fifteenth aspect of the present invention, in the image forming apparatus according to any one of the first to fourteenth aspects, the image forming apparatus further includes a fixing oscillating mechanism that oscillates the fixing device in a direction orthogonal to a sheet conveyance direction, The control means calculates the degree of damage based on the position of the fixing device rocked by the fixing rocking mechanism.

  According to a sixteenth aspect of the present invention, in the image forming apparatus according to any one of the first to fifteenth aspects, a sheet shift mechanism that shifts the position of the sheet relative to the fixing device in a direction orthogonal to the sheet conveyance direction. The control means calculates the degree of damage based on the position of the sheet relative to the fixing device shifted by the sheet shift mechanism.

  The invention according to claim 17 is the image forming apparatus according to any one of claims 1 to 16, further comprising a polishing mechanism that polishes a surface of the fixing roller, wherein the control unit is configured to perform the polishing by the polishing mechanism. When the surface of the fixing roller is polished, a predetermined value is subtracted from the degree of damage.

  According to an eighteenth aspect of the present invention, in the image forming apparatus according to any one of the first to seventeenth aspects, the fixing device is replaceable, and the storage means is provided for each fixing device. The degree of damage for each position is stored.

  According to a nineteenth aspect of the present invention, there is provided a job management system comprising: a plurality of image forming apparatuses; and a server apparatus connected to the plurality of image forming apparatuses via a communication network so that data communication is possible. Each of the forming devices is the image forming device according to any one of claims 1 to 18, and the server device includes a position and damage in a longitudinal direction of the fixing roller for each of the plurality of image forming devices. Based on server storage means for storing degrees in association with each other, the size of paper corresponding to a job, and the degree of damage for each position of each of the plurality of image forming apparatuses stored in the server storage means Selecting means for selecting an image forming apparatus for executing the job among the plurality of image forming apparatuses.

  The invention described in claim 20 is a job management system comprising a plurality of image forming apparatuses and a server apparatus connected to the plurality of image forming apparatuses via a communication network so as to be able to perform data communication. Each of the forming devices is the image forming device according to any one of claims 1 to 18, and the server device includes a position and damage in a longitudinal direction of the fixing roller for each of the plurality of image forming devices. Based on server storage means for storing degrees in association with each other, print information corresponding to a job, and damage degree for each position of each of the plurality of image forming apparatuses stored in the server storage means Selecting means for selecting an image forming apparatus for executing the job among the plurality of image forming apparatuses.

  According to the present invention, damage to the fixing roller can be grasped for each position in the longitudinal direction of the fixing roller.

1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment. FIG. 3 is a schematic view of the fixing device viewed from the roller axial direction. FIG. 4 is a schematic view of the fixing device as viewed from a sheet conveyance direction. 2 is a block diagram illustrating a functional configuration of the image forming apparatus. FIG. It is a flowchart which shows a damage degree calculation process. It is an example of a display of the damage degree for every paper size. It is an example of a display when a damage degree reaches a threshold value. It is a display example of the damage degree along the longitudinal direction of the fixing roller. It is a flowchart which shows the 1st print permission judgment processing. It is a flowchart which shows the 2nd print availability judgment processing. It is a figure which shows the result of having evaluated whether the damage | wound of a fixing roller affects an image using the fixing roller of a different damage degree for every kind of print information. It is a display example which shows whether it can print for every kind of print information. 10 is a flowchart illustrating third print permission / inhibition determination processing. It is a flowchart which shows the 1st printable sheet number display process. 10 is a flowchart showing a second printable sheet number display process. It is a flowchart which shows a 1st threshold value change process. It is a flowchart which shows a 2nd threshold value change process. It is a block diagram of the fixing rocking mechanism in the first modification of the first embodiment. It is a block diagram of the paper shift mechanism in the modification 2 of 1st Embodiment. It is the schematic diagram which looked at the fixing device in the modification 3 of 1st Embodiment from the roller axial direction. It is a flowchart which shows a damage recovery process. It is a system configuration figure of the job management system in a 2nd embodiment. 6 is a flowchart illustrating a first image forming apparatus selection process. 10 is a flowchart illustrating second image forming apparatus selection processing.

[First Embodiment]
First, the image forming apparatus 100 according to the first embodiment of the present invention will be described.

FIG. 1 is a schematic configuration diagram of the image forming apparatus 100.
The image forming apparatus 100 is a tandem color image forming apparatus that forms a color image by an electrophotographic method based on image data obtained by reading an image from a document or image data received from an external device. .

  As shown in FIG. 1, the image forming apparatus 100 includes an image forming unit 10, an image reading unit 20, a paper feeding unit 30, and the like.

  The image forming unit 10 heats and applies yellow (Y), magenta (M), cyan (C), black (K), image forming units 8Y, 8M, 8C, and 8K for each color, the intermediate transfer belt 5, and the toner image. A fixing device 9 for fixing by pressure is provided.

  The image forming unit 8Y includes a photosensitive drum 1Y that forms a yellow toner image, a yellow charging unit 2Y, an exposure unit 3Y, a developing unit 4Y, and a photosensitive member cleaning unit 7Y disposed around the photosensitive drum 1Y. .

  The image forming unit 8M includes a photosensitive drum 1M that forms a magenta toner image, a magenta charging unit 2M, an exposure unit 3M, a developing unit 4M, and a photosensitive member cleaning unit 7M disposed around the photosensitive drum 1M. .

  The image forming unit 8C includes a photosensitive drum 1C for forming a cyan toner image, a cyan charging unit 2C, an exposure unit 3C, a developing unit 4C, and a photosensitive member cleaning unit 7C disposed around the photosensitive drum 1C. .

  The image forming unit 8K includes a photosensitive drum 1K that forms a black toner image, a black charging unit 2K, an exposure unit 3K, a developing unit 4K, and a photosensitive member cleaning unit 7K disposed around the photosensitive drum 1K. .

The charging units 2Y, 2M, 2C, and 2K uniformly charge the photosensitive drums 1Y, 1M, 1C, and 1K, respectively.
Each of the exposure units 3Y, 3M, 3C, and 3K includes a laser light source, a polygon mirror, a lens, and the like, and scans and exposes the surface of the photosensitive drums 1Y, 1M, 1C, and 1K with a laser beam based on the image data of each color. Thus, an electrostatic latent image is formed.
The developing units 4Y, 4M, 4C, and 4K perform development by attaching toner of each color to the electrostatic latent images on the photosensitive drums 1Y, 1M, 1C, and 1K.

The toner images of the respective colors formed on the photosensitive drums 1Y, 1M, 1C, and 1K are sequentially transferred onto the rotating intermediate transfer belt 5 by the primary transfer rollers 6Y, 6M, 6C, and 6K (primary transfer). ). That is, a color toner image in which four color toner images are superimposed is formed on the intermediate transfer belt 5.
The color toner image on the intermediate transfer belt 5 is collectively transferred onto the one surface of the paper supplied from the paper supply unit 30 by the secondary transfer roller 6A (secondary transfer).

  The sheet on which the color toner image has been transferred is subjected to a fixing process by the fixing device 9 and is discharged onto a discharge tray. The toner remaining on the peripheral surfaces of the photoreceptor drums 1Y, 1M, 1C, and 1K after the transfer is cleaned by the photoreceptor cleaning units 7Y, 7M, 7C, and 7K, and enters the next image forming cycle. Further, after the color toner image is transferred onto the paper by the secondary transfer roller 6A, the residual toner is removed from the intermediate transfer belt 5 by the intermediate transfer belt cleaning unit 7A.

  The image reading unit 20 includes a scanner below the contact glass on which the document is placed, and reads an image of the document. The scanner is composed of a light source, a CCD (Charge Coupled Device) image sensor, an A / D converter, etc., and reads the image of the document by imaging and photoelectrically converting the reflected light of the light scanned from the light source to the document. The read image is A / D converted, and the obtained image data is output to the control unit 11 (see FIG. 4). The image reading unit 20 includes an ADF (automatic document feeder), and automatically feeds a document placed on the ADF to automatically read a document image.

  The paper feed unit 30 supplies the paper stored in the paper feed cassette to the image forming unit 10.

Next, the fixing device 9 will be described.
FIG. 2 is a schematic diagram of the fixing device 9 as viewed from the roller axis direction, and FIG. 3 is a schematic diagram of the fixing device 9 as viewed from the sheet conveyance direction.

  The fixing device 9 includes a fixing roller 91, a pressing roller 92, a support portion 93, and a spring 94. The fixing roller 91 includes heating means such as a halogen heater, and rotates around a roller shaft 91A. The pressing roller 92 is pressed against the fixing roller 91 by the spring 94 via the support portion 93 at both ends in the longitudinal direction of the pressing roller 92, and rotates with the rotation of the fixing roller 91 about the roller shaft 92A. To do. The support portions 93 are provided at both ends of the pressing roller 92 in the longitudinal direction. The support portion 93 is rotatable about the fixed shaft 93 </ b> A, and is supported by the roller shaft 92 </ b> A of the pressure roller 92 by the pressing force of the spring 94 to support the pressure roller 92.

The support unit 93 is provided with the displacement measuring unit 16. The displacement measuring unit 16 measures the displacement of the pressing roller 92 in the direction facing the fixing roller 91 when the sheet passes through the fixing device 9. As the displacement measuring unit 16, a laser displacement meter, a strain gauge, a line sensor, or the like is used.
3 illustrates the case where the displacement measurement unit 16 is provided only on one support part 93, the displacement measurement unit 16 may be provided on both support parts 93. In that case, an average value of displacements respectively measured by the two displacement measuring units 16 is used.

  As shown in FIG. 3, when the paper passes through the fixing device 9, the end position of the paper in the longitudinal direction (arrow X direction) of the fixing roller 91 is damaged.

FIG. 4 is a block diagram illustrating a functional configuration of the image forming apparatus 100.
4, the image forming apparatus 100 includes a control unit 11, an operation unit 12, a display unit 13, a storage unit 14, a communication unit 15, a displacement measurement unit 16, a line sensor 17, an image forming unit 10, and an image reading unit. 20, a paper feed unit 30, a transport unit 40, and the like. Note that description of the functional units already described is omitted.

  The control unit 11 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. In response to an operation signal input from the operation unit 12 or an instruction signal received by the communication unit 15, the CPU reads a system program or various processing programs stored in the ROM, expands the program in the RAM, and expands the program. Accordingly, the operation of each part of the image forming apparatus 100 is centrally controlled.

  The operation unit 12 includes a touch panel formed to cover the display screen of the display unit 13 and various operation buttons such as numeric buttons and a start button, and outputs an operation signal based on a user operation to the control unit 11. The operation unit 12 receives an operation instruction from a user.

  The display unit 13 is configured by an LCD (Liquid Crystal Display), and displays various screens according to instructions of display signals input from the control unit 11.

  The storage unit 14 is configured by a hard disk, a flash memory, or the like, and stores various data. The storage unit 14 stores the position of the fixing roller 91 in the longitudinal direction (the direction of the arrow X shown in FIG. 3) and the degree of damage in association with each other. The storage unit 14 stores a predetermined threshold value. Further, the storage unit 14 stores a position through which the end of the sheet passes in the longitudinal direction of the fixing roller 91 for each sheet size.

  The communication unit 15 transmits / receives data to / from an external device connected to a communication network such as a LAN (Local Area Network).

  As shown in FIG. 1, the line sensor 17 is provided downstream from the fixing device 9 and reads an image from the sheet after fixing. The line sensor 17 is composed of a light source, a CCD image sensor, an A / D converter, and the like, and forms an image of the reflected light of the light scanned from the light source onto the document and photoelectrically converts the image on the fixed paper. The read image is subjected to A / D conversion, and the obtained image data is output to the control unit 11.

  The transport unit 40 includes transport rollers for transporting paper, such as registration rollers 41 (see FIG. 1), and transports the paper in the image forming apparatus 100.

Next, the operation in the image forming apparatus 100 will be described.
FIG. 5 is a flowchart showing damage degree calculation processing executed in the image forming apparatus 100. This process is realized by software processing in cooperation with the CPU of the control unit 11 and the program stored in the ROM.

  First, the control unit 11 determines whether it is the measurement timing of the displacement of the pressing roller 92 (step S1). The measurement timing may be, for example, every sheet passing, every predetermined number of sheets of the same size, multiple times of fixing one sheet (for example, at the time of sheet entry, in the middle, immediately before sheet discharge), and the like. When it is not the measurement timing of the displacement of the pressing roller 92 (step S1; NO), the process returns to step S1.

  When it is the measurement timing of the displacement of the pressing roller 92 (step S1; YES), the control unit 11 determines the edge of the sheet in the longitudinal direction of the fixing roller 91 from the storage unit 14 according to the size of the sheet to be printed. The position through which is passed is acquired (step S2). That is, the control unit 11 functions as an acquisition unit.

  Next, the control unit 11 detects the displacement in the direction facing the fixing roller 91 of the pressing roller 92 when the sheet passes through the fixing device 9, which is measured by the displacement measuring unit 16 with the printing by the image forming unit 10. Obtain (step S3).

  Next, the control unit 11 sets a value based on the displacement measured by the displacement measuring unit 16 and the length (fixing distance) in the transport direction of the sheet that has passed through the fixing device 9 for each position stored in the storage unit 14. Is added to the damage degree corresponding to the passing position of the paper edge acquired in step S2, and a new damage degree is calculated (step S4). In the storage unit 14, the control unit 11 overwrites and updates the degree of damage corresponding to the passing position of the sheet edge. That is, the degree of damage corresponding to each position in the longitudinal direction of the fixing roller 91 is accumulated for each position based on the displacement measured by the displacement measuring unit 16 and the length in the transport direction of the sheet that has passed through the fixing device 9. Value.

  For example, the displacement measured by the displacement measuring unit 16 is a value based on the displacement measured by the displacement measuring unit 16 and the length in the transport direction of the sheet that has passed through the fixing device 9 (a value that is cumulatively added to the damage degree). And the product of the lengths in the transport direction of the sheet that has passed through the fixing device 9 can be used. Alternatively, a value obtained by multiplying the product by a coefficient may be used.

  When the displacement of the pressure roller 92 is measured for each sheet, the length in the conveyance direction of the sheet that has passed through the fixing device 9 is the sheet size, and the length of the pressure roller 92 is once for a plurality of sheets of the same size. When the displacement is measured, the paper size × the number of sheets. Further, the displacement of the pressing roller 92 is measured a plurality of times with one sheet passing, time series data of the displacement is acquired, and the value obtained by integrating the displacement of the pressing roller 92 with the position (distance) in the sheet conveyance direction is You may use for calculation of a damage degree.

  In addition, weighting may be performed when obtaining a value based on the displacement measured by the displacement measuring unit 16 and the length in the transport direction of the sheet that has passed through the fixing device 9.

  Specifically, the weighting is changed depending on the material, rigidity, hardness, friction coefficient, elastic modulus and the like of the fixing roller 91. For example, for the material F1 of the fixing roller 91, the weighting is 1 when the elastic modulus is 5 MPa, and the weighting is 2 when the elastic modulus is 10 MPa. Further, the material F2 of the fixing roller 91 is given a weight of 5 with an elastic modulus of 5 MPa, and a weight of 7 with an elastic modulus of 10 MPa. Also, the higher the rigidity of the fixing roller 91, the smaller the weight, the lower the weight, the smaller the weight, and the greater the friction coefficient, the greater the weight.

  Further, since the change in the thickness of the paper when passing through the fixing device 9 causes a difference in the damage in the radial direction of the fixing roller 91, the thickness of the paper is measured before passing through the fixing device 9, and the fixing device 9. This is combined with the displacement of the pressing roller 92 when passing through. Further, the rigidity in the thickness direction of the sheet is measured before and after passing through the fixing device 9 and reflected in the degree of damage. Specifically, the weighting is increased as the thickness of the sheet is increased, and the weighting is increased as the rigidity in the thickness direction of the sheet is increased. For example, assuming that the paper thickness is t1 and the paper rigidity is E1, weighting proportional to (t1) ^ 3 × E1 can be used. The paper thickness t1 can be in the range of 0.05 to 1.0 mm.

  In addition, the weighting may be changed within one sheet, for example, by increasing the weighting at the leading and trailing edges of the sheet from the center of the sheet.

  Further, when the paper passes once through the fixing device 9 such as double-sided printing or follow-up printing, the influence of the thickness of the toner fixed on the paper and its position is reflected in the calculation of the damage degree from the print information. For example, as weighting when printing the second side of double-sided printing, the paper thickness is t1, the thickness that decreases when the paper passes through the fixing device 9 is t2, and the value based on the toner printing rate is t3. Use t2 + t3. Note that the value t3 based on the toner printing rate is larger as the toner printing rate is higher.

  Further, the condition of the applied load with respect to the pressing force of the pressing roller 92 differs depending on the paper size, and the influence on the scratches on the surface of the fixing roller 91 also differs. Specifically, the weighting is increased as the paper size is smaller.

  Next, the control unit 11 determines whether or not the degree of damage corresponding to the passing position of the paper edge is greater than or equal to a predetermined threshold (step S5). If the degree of damage corresponding to the passing position of the paper edge is equal to or greater than the threshold (step S5; YES), the control unit 11 notifies the user that the degree of damage has reached the threshold (step S6). For example, the control unit 11 causes the display unit 13 to display that the damage level has reached a threshold value, or the damage level for each position in the longitudinal direction of the fixing roller 91 stored in the storage unit 14.

FIG. 6 is a display example of the degree of damage for each paper size (paper feed tray). The degree of damage of a certain paper size means the degree of damage corresponding to the position through which the end of the paper of that size passes in the longitudinal direction of the fixing roller 91. In FIG. 6, the damage degree value stored in the storage unit 14 is not displayed as (damage degree / threshold value) × 100 (%).
Thus, since the damage level corresponding to the passage position of the paper edge of each paper size is displayed on the display unit 13, it is possible to notify the user of the damage level at the position corresponding to each paper size.

  FIG. 7 is a display example when the degree of damage reaches a threshold value. FIG. 7 shows an example of the case where the damage level of the B6 size reaches the threshold value. Since the same notation as in FIG. 6 is used, the damage level is displayed as 100%. Since a sheet wider than the B6 size in the longitudinal direction of the fixing roller 91 passes through the end position of the B6 size sheet, a warning “an image defect appears on a sheet larger than B6” is displayed. Yes.

FIG. 8 is a display example of the degree of damage along the longitudinal direction of the fixing roller 91. The position at which the end of the sheet passes is linearly symmetric with the longitudinal center position of the fixing roller 91 as the symmetry axis, the right end in FIG. 8 corresponds to the center position of the fixing roller 91, and the left end is fixed. This corresponds to the end of the roller 91. In FIG. 8, 100% notation is used as in FIG.
Thus, since the damage degree for every position in the longitudinal direction of the fixing roller 91 is displayed on the display unit 13, the damage degree for each position can be notified to the user.

In step S5, when the degree of damage corresponding to the passing position of the paper edge is less than the threshold value (step S5; NO), or after step S6, the control unit 11 stores in the storage unit 14 by the communication unit 15. The degree of damage for each position is transmitted to a server device as an external device connected to the communication network (step S7).
This is the end of the damage degree calculation process.

  In the server device, the damage degree at each position in the longitudinal direction of the fixing roller 91 transmitted from the image forming apparatus 100 is stored, and when the damage degree at any position exceeds a threshold, the fixing roller 91 When it is determined that the replacement is necessary, the service person visits the office where the image forming apparatus 100 is installed and performs maintenance such as replacement of the fixing roller 91.

  In step S4, instead of calculating the degree of damage corresponding to the passing position of the sheet edge, a value based on the displacement measured by the displacement measuring unit 16 and the length in the transport direction of the sheet passing through the fixing device 9 ( The value newly added) may be stored only in the storage unit 14. A value based on the displacement measured by the displacement measuring unit 16 and the length in the transport direction of the sheet that has passed through the fixing device 9 is transmitted to the external device. In the external device, the degree of damage at each position in the longitudinal direction of the fixing roller 91 is transmitted. May be calculated (cumulative addition).

  FIG. 9 is a flowchart showing the first print propriety determination process executed in the image forming apparatus 100. This processing is executed when a print request is made, and is realized by software processing in cooperation with the CPU of the control unit 11 and a program stored in the ROM.

  First, the control part 11 acquires the damage degree for every position memorize | stored in the memory | storage part 14 (step S11).

  Next, the control unit 11 compares each degree of damage for each position with a threshold value stored in the storage unit 14, and determines whether or not the degree of damage at any position is greater than or equal to the threshold value (step S12). ).

  If the damage degree at any position is greater than or equal to the threshold (step S12; YES), the control unit 11 determines the length of the fixing roller 91 from the storage unit 14 according to the size of the print target paper requested to be printed. The position through which the end of the sheet passes in the direction is acquired (step S13).

  Next, the control unit 11 determines whether or not the sheet passes through a position where the degree of damage is equal to or more than a threshold in the current print based on the passage position of the sheet end acquired in step S13 (step S14). .

  In the current printing, when the paper passes through a position where the degree of damage is equal to or greater than the threshold (step S14; YES), the control unit 11 stops the printing (step S15). That is, the control unit 11 stops the printing of the paper size that passes the position where the damage degree has reached the threshold value.

  In step S12, when the damage level of all positions is less than the threshold value (step S12; NO), or in step S14, when the sheet does not pass through the position where the damage level is equal to or higher than the threshold value (step S14) S14; NO), the control unit 11 causes the printing to be performed (step S16).

Further, the control unit 11 acquires the displacement in the direction facing the fixing roller 91 of the pressing roller 92 when the sheet passes through the fixing device 9, which is measured by the displacement measuring unit 16 at the time of printing, and based on this displacement. The damage degree stored in the storage unit 14 is updated (step S17). A specific method for calculating the damage degree is the same as that in steps S2 to S4 in FIG.
In addition, when the printing time of step S16 is not the measurement timing of the displacement of the pressing roller 92, the process of step S17 is not performed.
After step S15 or step S17, the first print availability determination process ends.

According to the first print possibility determination process, when one of the damage degrees for each position stored in the storage unit 14 reaches a threshold value, the paper size of the sheet passing through the position where the damage degree has reached the threshold value is determined. Since printing is stopped, image defects due to scratches on the fixing roller 91 can be prevented.
On the other hand, even if one of the damage levels for each position stored in the storage unit 14 reaches the threshold value, printing is performed for a paper size that does not pass through the position where the damage level has reached the threshold value. When the flaw of the fixing roller 91 is outside the sheet range, the fixing roller 91 can be used continuously.

  In the first print possibility determination process, when the damage degree at any position is equal to or greater than the threshold value (step S12; YES), the control unit 11 performs printing without performing the processes of steps S13 and S14. It is good also as stopping (step S15). In this case, it is possible to prevent an image defect due to a flaw on the fixing roller 91 regardless of whether or not the sheet passes through a position where the degree of damage is greater than or equal to the threshold value in the current print.

  In step S15 and step S16, whether or not printing is possible may be displayed on the display unit 13.

  FIG. 10 is a flowchart illustrating a second print permission determination process executed in the image forming apparatus 100. This processing is executed when a print request is made, and is realized by software processing in cooperation with the CPU of the control unit 11 and a program stored in the ROM.

  First, the control part 11 acquires the damage degree for every position memorize | stored in the memory | storage part 14 (step S21).

  Next, the control unit 11 acquires print information requested for printing (step S22).

  Next, the control unit 11 compares each degree of damage for each position with a threshold value stored in the storage unit 14, and determines whether or not the degree of damage at any position is greater than or equal to the threshold value (step S23). ).

  If the damage degree at any position is greater than or equal to the threshold (step S23; YES), the control unit 11 determines whether or not a position with the damage degree greater than or equal to the threshold is an image region based on the print information. (Step S24). Here, the image area refers to an area where an image (including photographs, figures, characters, etc.) is formed. On the other hand, an area where no image is formed is referred to as a non-image area.

  When the position with the damage degree equal to or greater than the threshold is an image area (step S24; YES), the control unit 11 determines whether the position with the damage degree equal to or greater than the threshold is a character area based on the print information. (Step S25).

  In step S25, if the position where the damage degree is equal to or greater than the threshold is not a character area (step S25; NO), the control unit 11 displays on the display unit 13 that printing based on the print information requested for printing is not possible. (Step S26).

  Here, although there is a possibility that an image defect may occur, if the user still wants to print, the user gives a print instruction from the operation unit 12. The control unit 11 determines whether there is a print instruction from the operation unit 12 (step S27). If there is no print instruction (step S27; NO), the process ends.

  In step S23, when the damage degree of all positions is less than the threshold value (step S23; NO), in step S24, when the position where the damage degree is equal to or greater than the threshold value is not an image region (step S24; NO), in step S25, If the position where the degree of damage is greater than or equal to the threshold is a character area (step S25; YES), the control unit 11 causes the display unit 13 to display that printing based on the print information requested for printing is possible (step S25). S28).

  After step S28 or when there is a print instruction in step S27 (step S27; YES), the control unit 11 controls the image forming unit 10 to perform printing (step S29).

Further, the control unit 11 acquires the displacement in the direction facing the fixing roller 91 of the pressing roller 92 when the sheet passes through the fixing device 9, which is measured by the displacement measuring unit 16 at the time of printing, and based on this displacement. The damage degree stored in the storage unit 14 is updated (step S30). A specific method for calculating the damage degree is the same as that in steps S2 to S4 in FIG.
In addition, when the printing time of step S29 is not the measurement timing of the displacement of the pressing roller 92, the process of step S30 is not performed.
Thus, the second print availability determination process is completed.

  According to the second printability determination process, even if any of the damage degrees for each position stored in the storage unit 14 has reached the threshold, the position where the damage has reached the threshold is a non-image. Since the printing is performed in the area or the character area, the fixing roller 91 can be continuously used when the flaw of the fixing roller 91 does not affect the image. Thereby, the lifetime of the fixing roller 91 can be further extended.

  Further, based on the degree of damage for each position stored in the storage unit 14, a predetermined threshold value, and the print information requested to be printed, it is determined whether printing is possible, and the determination result is displayed on the display unit. 13, it is possible to notify the user whether printing is possible.

  Further, the acquisition of the damage degree in step S21 may be after the acquisition of the print information in step S22. In that case, if there is a non-image area in the longitudinal direction of the fixing roller 91, it is not necessary to acquire the degree of damage at that position.

  Further, in the acquisition of the print information in step S22, it is not necessary to acquire the print information at the position where the damage degree is less than the threshold value.

Further, since the influence on the image due to the damage of the fixing roller 91 differs depending on the type of print information (character / photo, print rate, pattern, etc.), a different threshold may be provided for each type of print information. In this case, the storage unit 14 stores a predetermined threshold value for each type of print information.
The control unit 11 determines whether printing is possible based on the degree of damage for each position stored in the storage unit 14, the threshold value for each type of print information, and the print information requested to be printed. The determination result is displayed on the display unit 13.

  In FIG. 11, for each type of print information (images G1 to G3), whether or not a flaw on the fixing roller 91 affects the image by using the fixing roller 91 having a damage degree H1 to H3 (H1> H2> H3). The result of having evaluated is shown. For the image G1, the flaw of the fixing roller 91 affected the image (occurrence of defective image) even when any fixing roller 91 having a damage level of H1 to H3 was used. Regarding the image G2, the flaw of the fixing roller 91 affected the image when the fixing roller 91 having the damage degree H1, H2 was used, but the flaw of the fixing roller 91 was used when the fixing roller 91 having the damage degree H3 was used. Did not affect the image. Regarding the image G3, the flaw on the fixing roller 91 affected the image when the fixing roller 91 having the damage degree H1 was used, but the flaw on the fixing roller 91 was used when the fixing roller 91 having the damage degree H2 and H3 was used. Did not affect the image.

  For example, the threshold for determining whether or not the image G1 can be printed is set to a value smaller than the damage degree H3. In addition, a threshold for determining whether or not the image G2 can be printed is set between the damage level H2 and the damage level H3. In addition, a threshold for determining whether or not the image G3 can be printed is set between the damage level H1 and the damage level H2.

FIG. 12 is a display example showing whether printing is possible for each type of print information (images G1 to G3). For example, the text data can be printed but the photograph / solid image cannot be printed.
As described above, when it is determined whether printing based on the print information requested for printing is possible based on a plurality of threshold values predetermined for each type of print information, for each type of print information. The user can be notified whether printing is possible.
It may be displayed whether printing is possible for each paper size in the paper feed tray.

  FIG. 13 is a flowchart showing a third print propriety determination process executed in the image forming apparatus 100. This processing is executed when a print request is made, and is realized by software processing in cooperation with the CPU of the control unit 11 and a program stored in the ROM.

  The third print propriety determination process is different from the second print propriety determination process in that the process of step S31 is performed, but the other processes are the same as the second print propriety determination process, and thus the same process is performed. Are given the same step number and the description is omitted.

  After step S26, the control unit 11 determines whether or not there has been an instruction to change print information from the operation unit 12 based on a user operation (step S31). The print information change instruction is, for example, an instruction to change the vertical and horizontal directions of the paper. When there is a print information change instruction from the operation unit 12 (step S31; YES), the process proceeds to step S22, and the process is repeated based on the changed print information.

  In step S31, when there is no print information change instruction from the operation unit 12 (step S31; NO), the process proceeds to step S27.

  According to the third print propriety determination process, it is possible to determine again whether or not printing based on the print information is possible by changing the print information.

  FIG. 14 is a flowchart showing a first printable sheet number display process executed in the image forming apparatus 100. This process is executed when an instruction to display the number of printable sheets for each paper size is given, and is a software process based on cooperation between the CPU of the control unit 11 and the program stored in the ROM. It is realized by.

  First, the control part 11 acquires the damage degree for every position memorize | stored in the memory | storage part 14 (step S41).

  Next, the control unit 11 acquires the position through which the end of the sheet passes in the longitudinal direction of the fixing roller 91 from the storage unit 14 for each sheet size (step S42).

  Next, the control unit 11 calculates the damage degree per sheet for each sheet size (step S43). The damage degree per sheet is a predicted value of a value that is added to the damage degree corresponding to the passing position of the edge of the sheet when one sheet of the sheet passes. For example, for each paper size, the control unit 11 determines the per-sheet size based on the displacement measured by the displacement measuring unit 16 when the paper passes through the fixing device 9 and the length of the paper in the transport direction. Calculate the degree of damage. The displacement used here may be acquired from past data accumulated in advance. In addition, you may use the average value of the displacement measured about several sheets of paper for every paper size.

Next, the control unit 11 calculates the number of printable sheets for each paper size (step S44). For example, the number of printable sheets can be calculated by the following formula.
Number of printable sheets = {(predetermined threshold) − (current damage level corresponding to the passing position of the sheet edge)} / (damage level per sheet)

Next, the control unit 11 displays the number of printable sheets on the display unit 13 for each paper size (step S45).
Thus, the first printable sheet number display process is completed.

  According to the first printable sheet number display process, the printable sheet number is calculated for each sheet size, and the calculated printable sheet number is displayed on the display unit 13, so that the user can print for each sheet size. Can be notified.

  FIG. 15 is a flowchart showing a second printable sheet number display process executed in the image forming apparatus 100. This process is executed when there is an instruction to display the printable number of print information types, and is based on the cooperation of the CPU of the control unit 11 and the program stored in the ROM. Realized by software processing.

  First, the control part 11 acquires the damage degree for every position memorize | stored in the memory | storage part 14 (step S51).

  Next, the control unit 11 acquires the position through which the end of the sheet passes in the longitudinal direction of the fixing roller 91 from the storage unit 14 for a predetermined sheet size (step S52). The predetermined paper size is designated from the operation unit 12 by the user, for example. Alternatively, a paper size that is frequently used in the image forming apparatus 100 may be automatically specified.

  Next, the control unit 11 calculates the degree of damage per sheet for each type of print information (step S53). For example, for each type of print information, the control unit 11 is based on the displacement measured by the displacement measurement unit 16 when a sheet of a predetermined size passes through the fixing device 9 and the length in the conveyance direction of the sheet. Calculate the degree of damage per sheet. The process of step S53 is basically the same as the process of step S43 of the first printable sheet number display process. However, when the weight for calculating the degree of damage is different for each type of print information, The degree of damage per sheet differs for each type of print information.

Next, the control unit 11 calculates the number of printable sheets for each type of print information (step S54). For example, the number of printable sheets can be calculated by the following formula.
Number of printable sheets = {(predetermined threshold value for each type of print information) − (current damage level corresponding to the passing position of the sheet edge)} / (damage level per sheet)

Next, the control unit 11 displays the number of printable sheets on the display unit 13 for each type of print information (step S55).
Thus, the second printable sheet number display process is completed.

  According to the second printable sheet number display process, the printable sheet number is calculated for each type of print information, and the calculated printable sheet number is displayed on the display unit 13, so that the user can print for each type of print information. The possible number of sheets can be notified.

  FIG. 16 is a flowchart showing a first threshold value changing process executed in the image forming apparatus 100. This process is realized by software processing in cooperation with the CPU of the control unit 11 and the program stored in the ROM.

  As a premise of the first threshold value changing process, the server apparatus connected to the image forming apparatus 100 via the communication network transmits the sheet thickness, the rigidity in the thickness direction, and the type transmitted from the image forming apparatus 100. And the relationship between the displacement measurement value measured by the displacement measurement unit 16 is accumulated. An administrator in the server apparatus transmits a change instruction for changing to a more suitable threshold value to the image forming apparatus 100 based on information on paper used by the user of the image forming apparatus 100. Alternatively, the server apparatus may calculate a new threshold value according to a predetermined determination condition.

  First, the control unit 11 determines whether or not a threshold value change instruction is received by the communication unit 15 from a server device connected to the communication network (step S61). The threshold value change instruction transmitted from the server device includes the threshold value to be changed. When the threshold value is different for each type of print information, the threshold value change instruction includes a plurality of threshold values according to the type of print information. When the threshold value change instruction is not received from the server device (step S61; NO), the process returns to step S61.

When the threshold value change instruction is received from the server device (step S61; YES), the control unit 11 changes the threshold value stored in the storage unit 14 based on the received change instruction (step S62). ). That is, the control unit 11 functions as a changing unit. In the subsequent processing, the changed threshold value is used.
This completes the first threshold value changing process.

  According to the first threshold value changing process, the threshold value is changed based on the threshold value changing instruction received from the server device, so that it is possible to improve the accuracy of the determination as to whether printing is possible. For example, the threshold can be changed according to the thickness of the paper used by the user of the image forming apparatus 100, the rigidity in the thickness direction, the type, and the like.

  In addition, it is good also as changing the weight according to the thickness of a sheet | seat, the rigidity of a thickness direction, a kind, etc. used when calculating a damage degree based not only on a threshold value but on the instruction | indication from a server apparatus.

  In addition, the relationship between the information such as the thickness of the sheet, the rigidity in the thickness direction, and the type and the measurement value of the displacement measured by the displacement measuring unit 16 is not the server device but the storage unit 14 of the image forming apparatus 100. May be stored. In this case, the user of the image forming apparatus 100 may input a more appropriate threshold value from the operation unit 12 and change the threshold value based on the accumulated paper information.

  FIG. 17 is a flowchart illustrating the second threshold value changing process executed in the image forming apparatus 100. This process is performed when it is determined that printing is not possible (when the damage degree at any position is equal to or greater than the threshold value, or when the position where the damage degree is equal to or greater than the threshold value is an image area and not a character area). It is a process and is realized by a software process in cooperation with the CPU of the control unit 11 and a program stored in the ROM.

  First, the control unit 11 controls the image forming unit 10 to print a confirmation image on a sheet (step S71). The confirmation image is an image prepared in advance for confirming the image quality, and is, for example, a solid image having a density suitable for detecting a scratch.

  The user checks the confirmation image printed on the paper and determines whether there is an image defect. If there is no image defect in the confirmation image, or if there is an image defect in the confirmation image and it is within the allowable range, the user instructs the operation unit 12 to change the threshold value. Specifically, the threshold value may be changed to a larger value.

  The control unit 11 determines whether or not there is an instruction to change the threshold value from the operation unit 12 by a user operation (step S72). If there is no instruction to change the threshold value from the operation unit 12 (step S72; NO), the process ends.

When there is a threshold change instruction from the operation unit 12 (step S72; YES), the control unit 11 changes the threshold stored in the storage unit 14 based on the threshold change instruction (step S73). . That is, the control unit 11 functions as a changing unit.
This completes the second threshold value changing process.

  According to the second threshold value changing process, after the user actually confirms the confirmation image, the threshold value is changed based on the threshold value changing instruction from the user. The threshold can be changed.

  If the user confirms the confirmation image printed on the paper in a state where it is determined that printing is possible, and there is an image defect in the confirmation image, the threshold value can be changed to a smaller value. Good.

As described above, according to the first embodiment, the degree of damage corresponding to the position where the end of the sheet passes is calculated based on the displacement (actually measured value) of the pressing roller 92 when the sheet passes. Therefore, damage to the fixing roller 91 can be grasped for each position in the longitudinal direction of the fixing roller 91.
In addition, it is possible to promote the printing of the paper size or the print information that is not affected by the damage of the fixing roller 91, and to extend the replacement period of the fixing device 9.

  Instead of detecting scratches on the image by visual inspection by the user, the image read by the line sensor 17 used for measuring the image position is analyzed to detect image defects such as scratches from the image. It is good. When an image defect is detected, printing is stopped or the damage threshold is changed. Further, printing based on each print information may be actually performed, the printed image may be read by the line sensor 17 to detect an image defect, and whether or not printing is possible for each print information may be displayed. .

[Modification 1]
Next, Modification 1 of the first embodiment will be described.
Since the image forming apparatus in Modification 1 has the same configuration as the image forming apparatus 100 shown in the first embodiment, FIGS. 1 to 4 are used, and illustration and description of the configuration are omitted. Hereinafter, a configuration and processing characteristic of Modification 1 will be described.

FIG. 18 shows an example of the configuration of the fixing swing mechanism 50 that swings the fixing device 9.
The fixing swing mechanism 50 includes a fixing swing motor 51, a gear 52, and a worm gear 53. The fixing swing motor 51 is constituted by, for example, a stepping motor, and rotates forward and backward based on an instruction from the control unit 11. The gear 52 is fixed to the rotation shaft of the fixing oscillating motor 51, and the groove portion of the peripheral surface thereof meshes with the screw groove portion of the worm gear 53. One end of the worm gear 53 is fixed to the side surface of the housing 95 of the fixing device 9.

When the fixing oscillating motor 51 rotates forward or backward, the fixing device 9 moves in a direction (arrow X direction) orthogonal to the paper transport direction (arrow Y direction) via a drive transmission system including a gear 52 and a worm gear 53. ). As a result, the fixing roller 91, the pressing roller 92, the support portion 93, and the spring 94 inside the housing 95 are also swung in the arrow X direction together with the housing 95.
The fixing swing mechanism 50 is not limited to the above-described configuration, and the fixing device 9 may be swung in the arrow X direction using, for example, a rack and pinion, a cam, or the like.

  In the first modification, the control unit 11 calculates the degree of damage based on the position of the fixing device 9 that is swung by the fixing rocking mechanism 50. Since the position of the fixing roller 91 in the longitudinal direction changes due to the swinging of the fixing device 9, the control unit 11 stores the reference position (stored in the storage unit 14) according to the swinging of the fixing device 9 by the fixing swinging mechanism 50. The sheet end position in the longitudinal direction of the fixing roller 91 corresponding to each sheet size is corrected, the actual sheet end position is calculated, and the degree of damage corresponding to the calculated position is calculated. Will be updated.

According to the first modification, the position where the sheet end passes with respect to the fixing device 9 can be moved by swinging the fixing device 9, so that the position of the flaw on the fixing roller 91 is in the longitudinal direction of the fixing roller 91. Can be dispersed.
Also, if it is determined that printing is not possible (such as when the damage level at any position is greater than or equal to the threshold value, or the position where the damage level is greater than or equal to the threshold value is an image area and not a character area), By causing the mechanism 50 to change the position of the fixing roller 91 in the longitudinal direction so that the sheet does not pass the position where the image defect occurs, the occurrence of the image defect may be avoided.

[Modification 2]
Next, Modification 2 of the first embodiment will be described.
Since the image forming apparatus in Modification 2 has the same configuration as that of the image forming apparatus 100 described in the first embodiment, FIGS. 1 to 4 are used, and illustration and description thereof are omitted. Hereinafter, a configuration and processing characteristic of Modification 2 will be described.

FIG. 19 shows an example of the configuration of the paper shift mechanism 60 that swings the paper. FIG. 19 shows a state in which a sheet is conveyed from the registration roller 41 to the fixing device 9.
The paper shift mechanism 60 includes a paper swing motor 61, a gear 62, and a worm gear 63. The paper swing motor 61 is constituted by a stepping motor, for example, and rotates forward and backward based on an instruction from the control unit 11. The gear 62 is fixed to the rotation shaft of the paper swing motor 61, and the groove portion of the peripheral surface thereof meshes with the screw groove portion of the worm gear 63. One end of the worm gear 63 is fixed to the shaft of the registration roller 41.

When the paper swing motor 61 rotates forward or backward, the registration roller 41 passes in a direction (arrow X direction) orthogonal to the paper transport direction (arrow Y direction) via a drive transmission system including a gear 62 and a worm gear 63. ). As a result, the sheet fed to the secondary transfer roller 6A side by the registration roller 41 is shifted in the arrow X direction.
The sheet shift mechanism 60 is not limited to the above configuration, and for example, the position of the sheet relative to the fixing device 9 may be shifted in the arrow X direction using a rack and pinion, a cam, or the like. Good.

  In the second modification, the control unit 11 calculates the degree of damage based on the position of the sheet with respect to the fixing device 9 shifted by the sheet shift mechanism 60. Since the position of the sheet in the longitudinal direction of the fixing roller 91 when it is fed into the fixing device 9 changes due to the swing of the registration roller 41, the control unit 11 determines the reference position according to the sheet shift by the sheet shift mechanism 60. (Passing position of the sheet end in the longitudinal direction of the fixing roller 91 corresponding to each sheet size stored in the storage unit 14) is corrected, and the actual passing position of the sheet end is calculated. The damage level corresponding to the position is updated.

According to the second modification, the position of the sheet with respect to the fixing device 9 is shifted in a direction perpendicular to the conveyance direction of the sheet, so that the position of the scratch on the fixing roller 91 can be dispersed in the longitudinal direction of the fixing roller 91.
In addition, when it is determined that printing is not possible (when the damage degree at any position is equal to or greater than the threshold value, or when the damage degree is equal to or greater than the threshold value is an image area and not a character area), the paper shift mechanism By changing the position of the sheet with respect to the fixing device 9 in the longitudinal direction of the fixing roller 91 by 60 so that the sheet does not pass the position where the image defect occurs, the occurrence of the image defect may be avoided. .

[Modification 3]
Next, Modification 3 of the first embodiment will be described.
Since the image forming apparatus in Modification 3 has the same configuration as that of the image forming apparatus 100 shown in the first embodiment, FIGS. 1 and 4 are used, and illustration and description thereof are omitted. Hereinafter, the configuration and processing characteristic of Modification 3 will be described.

FIG. 20 is a schematic view of the fixing device 9A according to Modification 3 as viewed from the roller axis direction.
The fixing device 9A includes a polishing roller 96 as a polishing mechanism that polishes the surface of the fixing roller 91 in addition to the same configuration as the fixing device 9 shown in FIG. The polishing roller 96 is disposed at a position where it can come into contact with the fixing roller 91 during polishing. The polishing roller 96 polishes the surface of the fixing roller 91 by giving a relative difference in linear velocity with the fixing roller 91 while being in contact with the fixing roller 91. As the polishing roller 96, for example, a surface layer portion made of stainless steel and a surface that is blasted and roughened is used. The polishing roller 96 has such a length as to straddle both ends in the longitudinal direction of the fixing roller 91 of the maximum size sheet to be passed.

  In the third modification, when the surface of the fixing roller 91 is polished by the polishing roller 96, the control unit 11 subtracts a predetermined value from the degree of damage corresponding to each position stored in the storage unit 14.

  FIG. 21 is a flowchart illustrating damage degree recovery processing executed in the image forming apparatus according to the third modification. This process is realized by software processing in cooperation with the CPU of the control unit 11 and the program stored in the ROM.

  First, the control unit 11 determines whether it is the polishing timing of the fixing roller 91 (step S81). The polishing timing can be arbitrarily set, for example, every predetermined number of sheets, every predetermined time, when the degree of damage at any position reaches a threshold, or when designated by the user. If it is not the polishing timing of the fixing roller 91 (step S81; NO), the process returns to step S81.

  When it is the polishing timing of the fixing roller 91 (step S81; YES), the control unit 11 brings the polishing roller 96 into contact with the fixing roller 91, and is relative to the linear velocity between the polishing roller 96 and the fixing roller 91. By providing the difference, the surface of the fixing roller 91 is polished by the polishing roller 96 (step S82).

Next, the control unit 11 subtracts a predetermined value from the degree of damage corresponding to each position stored in the storage unit 14 (step S83). The predetermined value may be changeable according to the polishing amount and the polishing time.
Thus, the damage degree recovery process is completed.

  According to the third modification, as the fixing roller 91 is polished by the polishing roller 96 to restore the uniformity of the surface of the fixing roller 91, the predetermined value is reduced from the degree of damage, which is suitable for the state of the fixing roller 91. Damage degree.

[Modification 4]
Next, Modification 4 of the first embodiment will be described.
Since the image forming apparatus in Modification 4 has the same configuration as that of the image forming apparatus 100 described in the first embodiment, FIGS. 1 to 4 are used, and illustration and description thereof are omitted. Hereinafter, a configuration and processing characteristic of Modification 4 will be described.

  In the image forming apparatus according to the fourth modification, the fixing device 9 can be replaced, and it is assumed that a plurality of fixing devices 9 are selectively used according to the size, thickness, and the like of the paper.

  The storage unit 14 stores the position of the fixing roller 91 in the longitudinal direction and the degree of damage in association with each fixing device 9.

When the fixing device 9 is attached to the image forming apparatus, the control unit 11 acquires identification information unique to the attached fixing device 9 and is associated with the acquired identification information during subsequent printing. The damage level for each position is updated. The identification information may be acquired by reading the identification information described in the fixing device 9 with a sensor, or the user may input the identification information from the operation unit 12.
When the fixing device 9 is replaced with another fixing device 9 and used again, the control unit 11 determines the degree of damage corresponding to each position of the fixing device 9 after replacement stored in the storage unit 14. Thus, the values based on the displacement measured by the displacement measuring unit 16 and the length in the paper transport direction are cumulatively added.

  According to the fourth modification, the degree of damage for each position can be managed for each fixing device 9.

  A plurality of characteristic configurations of the image forming apparatus according to the first embodiment and the first to fourth modifications may be combined.

[Second Embodiment]
Next, a second embodiment to which the present invention is applied will be described.
FIG. 22 shows a system configuration of the job management system 200 according to the second embodiment.
The job management system 200 includes a server device 70 and image forming apparatuses 100A, 100B, 100C,. The server device 70 and the image forming apparatuses 100A, 100B, 100C,... Are connected via a communication network N so that data communication is possible.

  Since the image forming apparatuses 100A, 100B, 100C,... Have the same configuration as that of the image forming apparatus 100 shown in the first embodiment, FIGS. Description is omitted. Note that the image forming apparatuses 100A, 100B, 100C,... May have the same configuration as that of the first to fourth modifications of the first embodiment.

  The server device 70 includes a control unit 71, an operation unit 72, a display unit 73, a storage unit 74, a communication unit 75, and the like.

  The control unit 71 includes a CPU, ROM, RAM, and the like. In response to an operation signal input from the operation unit 72 or an instruction signal received by the communication unit 75, the CPU reads a system program or various processing programs stored in the ROM, expands the program in the RAM, and expands the program. Accordingly, the operation of each part of the server device 70 is centrally controlled.

  The operation unit 72 includes a keyboard having character input keys, numeric input keys, various function keys, and the like, and a pointing device such as a mouse, and includes a key press signal pressed by the keyboard and an operation signal by the mouse. Is output to the control unit 71 as an input signal.

  The display unit 73 is configured by an LCD, and displays various screens according to instructions of display signals input from the control unit 71.

  The storage unit 74 is configured by a hard disk, a flash memory, or the like, and stores various data. In the storage unit 74, the position of the fixing roller 91 in the longitudinal direction and the degree of damage are stored in association with each other for each of the image forming apparatuses 100A, 100B, 100C,. The storage unit 74 stores a predetermined threshold value. The storage unit 74 stores a position through which the end of the sheet passes in the longitudinal direction of the fixing roller 91 for each sheet size.

  The communication unit 75 transmits and receives data to and from an external device connected to a communication network N such as a LAN.

Next, the operation in the server device 70 will be described.
FIG. 23 is a flowchart showing a first image forming apparatus selection process executed in the server apparatus 70. This process is realized by software processing in cooperation with the CPU of the control unit 71 and the program stored in the ROM.

  First, the control unit 71 causes the image forming apparatuses 100A, 100B, 100C,... To be connected to the image forming apparatuses 100A, 100B, 100C,. The degree of damage for each position stored in the storage unit 14 is acquired (step S91). The control unit 71 stores the position and the degree of damage in the storage unit 74 in association with each other for each image forming apparatus.

  Next, the control unit 71 acquires the position through which the end of the sheet passes in the longitudinal direction of the fixing roller 91 from the storage unit 74 according to the size of the sheet corresponding to the job (step S92).

  Next, the control unit 71 determines whether there is an image forming apparatus in which the degree of damage at all positions in the longitudinal direction of the fixing roller 91 is less than a threshold value (step S93).

  When there is an image forming apparatus in which the damage degree at all positions is less than the threshold value (step S93; YES), the control unit 71 determines the damage degree among the image forming apparatuses in which the damage degree at all positions is less than the threshold value. The image forming apparatus closest to the threshold is selected (step S94). For example, the damage degree corresponding to each position in the longitudinal direction of the fixing roller 91 is compared with each other, and the image forming apparatus closer to the threshold is selected.

  In step S93, when there is no image forming apparatus in which the damage degree of all positions is less than the threshold (step S93; NO), that is, in any of the image forming apparatuses 100A, 100B, 100C,. If the damage level is greater than or equal to the threshold value, the control unit 71 determines whether the sheet passes through a position where the damage level is greater than or equal to the threshold value in the current print based on the passage position of the paper edge acquired in step S92. It is determined whether or not (step S95).

  In the current print, when the sheet does not pass through the position where the damage degree is equal to or greater than the threshold (step S95; NO), the control unit 71 is the image forming apparatus in which the sheet does not pass the position where the damage degree is equal to or greater than the threshold. The image forming apparatus with the greatest damage degree is selected (step S96). For example, the damage degree corresponding to each position in the longitudinal direction of the fixing roller 91 is compared with each other, and the larger image forming apparatus is selected. In step S94 and step S96, the control unit 71 functions as a selection unit.

  In step S95, if the sheet passes through a position where the degree of damage is greater than or equal to the threshold value in the current print (step S95; YES), the control unit 71 notifies the user that there is a possibility of image failure. (Step S97).

  Here, although there is a possibility that an image defect may occur, if the user still wants to print, the user gives a print instruction from the operation unit 72. The control unit 71 determines whether or not there is a print instruction from the operation unit 72 (step S98). If there is no print instruction (step S98; NO), the process ends.

  If there is a print instruction in step S98 (step S98; YES), the user selects an image forming apparatus that performs printing from the operation unit 72.

After step S94, after step S96, or when there is a print instruction in step S98 (step S98; YES), the control unit 71 controls the selected image forming apparatus by the communication unit 75. Then, a print instruction for executing the job is transmitted (step S99). The print instruction includes paper size, print information, various setting information, and the like.
This completes the first image forming apparatus selection process.

  In the selected image forming apparatus, when the print instruction transmitted from the server apparatus 70 is received, the job is executed based on the print instruction.

  According to the first image forming apparatus selection process, a plurality of paper sizes are determined based on the size of the paper corresponding to the job and the degree of damage for each position of each of the plurality of image forming apparatuses stored in the storage unit 74. Among these image forming apparatuses, an image forming apparatus that executes a job can be selected.

  For example, if the sheet does not pass through a position where the degree of damage is equal to or greater than the threshold value in step S95, the image forming apparatus having the largest degree of damage is selected, so even if the degree of damage reaches the threshold value, the fixing roller When the scratches 91 do not affect the image, the fixing roller 91 can be used continuously. In this way, the fixing device 9 is replaced by a factor other than an image defect due to a flaw on the fixing roller 91, and the lifetime of the fixing roller 91 and the entire fixing device 9 is extended.

In step S94, the fixing device 9 is replaced by another functional factor by selecting an image forming apparatus having a damage degree closest to the threshold value.
However, when printing in large quantities, it is preferable to prevent the job from being interrupted as the degree of damage during the job increases.

  FIG. 24 is a flowchart showing a second image forming apparatus selection process executed in the server apparatus 70. This process is realized by software processing in cooperation with the CPU of the control unit 71 and the program stored in the ROM.

  First, the control unit 71 causes the image forming apparatuses 100A, 100B, 100C,... To be connected to the image forming apparatuses 100A, 100B, 100C,. The degree of damage for each position stored in the storage unit 14 is acquired (step S101). The control unit 71 stores the position and the degree of damage in the storage unit 74 in association with each other for each image forming apparatus.

  Next, the control unit 71 acquires print information corresponding to the job (step S102).

  Next, the control unit 71 determines whether there is an image forming apparatus in which the degree of damage at all positions in the longitudinal direction of the fixing roller 91 is less than a threshold value (step S103).

  When there is an image forming apparatus in which the degree of damage at all positions is less than the threshold (step S103; YES), the control unit 71 determines the degree of damage from among the image forming apparatuses in which the degree of damage at all positions is less than the threshold. Is selected closest to the threshold value (step S104). For example, the damage degree corresponding to each position in the longitudinal direction of the fixing roller 91 is compared with each other, and the image forming apparatus closer to the threshold is selected. Note that an image forming apparatus that executes a job may be selected based on conditions other than the degree of damage to the fixing roller 91 from among image forming apparatuses in which the degree of damage at all positions is less than the threshold.

  In step S103, when there is no image forming apparatus in which the damage degree of all positions is less than the threshold (step S103; NO), that is, in any of the image forming apparatuses 100A, 100B, 100C,. If the damage degree is greater than or equal to the threshold value, the control unit 71 determines whether or not the position where the damage degree is greater than or equal to the threshold value is an image region based on the print information (step S105).

  When the position where the damage degree is equal to or greater than the threshold is an image area (step S105; YES), the control unit 71 determines whether the position where the damage degree is equal to or greater than the threshold is a character area based on the print information. (Step S106).

  In step S105, when the position where the damage degree is not less than the threshold is not an image area (step S105; NO), the control unit 71 has a damage degree among the image forming apparatuses where the position where the damage degree is not less than the threshold is not an image area. The largest image forming apparatus is selected (step S107). In step S106, if the position where the degree of damage is greater than or equal to the threshold is a character area (step S106; YES), the control unit 71 is the image forming apparatus in which the position where the degree of damage is greater than or equal to the threshold is a character area. Then, the image forming apparatus having the largest damage degree is selected (step S107). For example, the damage degree corresponding to each position in the longitudinal direction of the fixing roller 91 is compared with each other, and the larger image forming apparatus is selected. In step S104 and step S107, the control unit 71 functions as a selection unit.

  After step S107 or in step S106, if the position where the degree of damage is greater than or equal to the threshold is not a character area (step S106; NO), the control unit 71 notifies the user that there is a possibility that an image defect will occur. (Step S108).

  Here, although there is a possibility that an image defect may occur, if the user still wants to print, the user gives a print instruction from the operation unit 72. The control unit 71 determines whether or not there is a print instruction from the operation unit 72 (step S109). If there is no print instruction (step S109; NO), the process ends.

  If it is determined in step S106 that the position where the degree of damage is equal to or greater than the threshold is not a character area (step S106; NO), and if there is a print instruction in step S109 (step S109; YES), the user An image forming apparatus that executes printing is selected from the operation unit 72.

After step S104 or when there is a print instruction in step S109 (step S109; YES), the control unit 71 causes the selected image forming apparatus to execute a job through the communication unit 75. A print instruction is transmitted (step S110).
The second image forming apparatus selection process is thus completed.

  In the selected image forming apparatus, when the print instruction transmitted from the server apparatus 70 is received, the job is executed based on the print instruction.

  According to the second image forming apparatus selection process, based on the print information corresponding to the job and the degree of damage for each position of the plurality of image forming apparatuses stored in the storage unit 74, a plurality of image forming apparatuses are selected. An image forming apparatus that executes a job can be selected from the image forming apparatuses.

  For example, in steps S105 and S106, when the position where the damage level is equal to or greater than the threshold value is a non-image area or a character area, the image forming apparatus having the highest damage level is selected. However, when the flaw on the fixing roller 91 does not affect the image, the fixing roller 91 can be used continuously. In this way, the fixing device 9 is replaced by a factor other than an image defect due to a flaw on the fixing roller 91, and the lifetime of the fixing roller 91 and the entire fixing device 9 is extended.

In step S104, the image forming apparatus whose damage degree is closest to the threshold value is selected, so that the fixing device 9 is replaced by another functional factor.
However, when printing in large quantities, it is preferable to prevent the job from being interrupted as the degree of damage during the job increases.

  Instead of acquiring the damage level in step S101, the damage level for each position stored in advance in the storage unit 14 of each of the image forming apparatuses 100A, 100B, 100C,. You may display the image forming apparatus with a damage degree more than a threshold value in any position. Alternatively, for each of the image forming apparatuses 100A, 100B, 100C,..., It may be displayed whether there is a position where the degree of damage is equal to or greater than a threshold value.

  Further, the damage level is acquired from the image forming apparatuses 100A, 100B, 100C,... In step S101 by acquiring only the damage level at a necessary position with respect to the target print position after confirming the print information. It is good.

  As described above, according to the second embodiment, the server device 70 acquires the damage degree for each position calculated in each of the image forming apparatuses 100A, 100B, 100C,. The damage of the fixing roller 91 in the forming apparatuses 100A, 100B, 100C,... Can be grasped for each position in the longitudinal direction of the fixing roller 91.

  The descriptions in the above embodiments are examples of the image forming apparatus and the job management system according to the present invention, and the present invention is not limited thereto. The detailed configuration and detailed operation of each part constituting each device can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 9 Fixing device 9A Fixing device 10 Image forming part 11 Control part 12 Operation part 13 Display part 14 Storage part 15 Communication part 16 Displacement measurement part 50 Fixing rocking mechanism 60 Paper shift mechanism 70 Server apparatus 71 Control part 72 Operation part 73 Display part 74 Storage unit 75 Communication unit 91 Fixing roller 92 Pressing roller 96 Polishing roller 100 Image forming apparatuses 100A, 100B, 100C,... Image forming apparatus 200 Job management system N Communication network

Claims (20)

In an image forming apparatus provided with a fixing device having a fixing roller and a pressing roller pressed against the fixing roller,
Storage means for storing the position in the longitudinal direction of the fixing roller and the degree of damage in association with each other;
An acquisition means for acquiring a position through which an end of the sheet passes in the longitudinal direction of the fixing roller;
A displacement measuring means for measuring a displacement of the pressing roller in a direction facing the fixing roller when a sheet passes through the fixing device;
Control means for storing in the storage means a value based on the displacement measured by the displacement measuring means and the length in the transport direction of the paper that has passed through the fixing device, as the degree of damage corresponding to the position obtained by the obtaining means. When,
An image forming apparatus comprising:   The degree of damage for each position stored in the storage means is a value obtained by accumulating a value based on the displacement measured by the displacement measuring means and the length in the transport direction of the paper passing through the fixing device for each position. The image forming apparatus according to claim 1, wherein   The image forming apparatus according to claim 1, wherein the control unit causes the display unit to display a damage degree for each position stored in the storage unit.   The control unit according to any one of claims 1 to 3, wherein the control unit stops printing when any of the degree of damage for each position stored in the storage unit reaches a predetermined threshold value. Image forming apparatus.   When one of the damage degrees for each position stored in the storage means has reached a predetermined threshold, the control means has a sheet size that passes through the position where the damage has reached the threshold. The image forming apparatus according to claim 1, wherein printing is stopped.   When one of the degree of damage for each position stored in the storage means reaches a predetermined threshold, the control means determines that the position where the degree of damage has reached the threshold is a non-image area or a character. 4. The image forming apparatus according to claim 1, wherein printing is performed when the area is an area, and printing is stopped when the position where the damage degree reaches the threshold is not a non-image area or a character area. .   The control means determines whether or not printing is possible based on the degree of damage for each position stored in the storage means, a predetermined threshold value and print information requested for printing, and the determination result The image forming apparatus according to claim 1, wherein the image is displayed on a display unit.   The image forming apparatus according to claim 7, wherein the threshold value is predetermined for each type of print information.   The control means calculates the degree of damage per sheet based on the displacement measured by the displacement measuring means when the paper passes through the fixing device for each paper size and the length in the conveyance direction of the paper. And calculating the number of printable sheets for each paper size based on the calculated damage per sheet, the damage for each position stored in the storage means, and a predetermined threshold. The image forming apparatus according to claim 1, wherein the calculated number of printable sheets is displayed on a display unit.   The control unit is configured to print a sheet of a predetermined size for each type of print information based on the displacement measured by the displacement measuring unit when the sheet passes through the fixing device and the length of the sheet in the conveyance direction. The degree of damage of the print information is calculated based on the calculated degree of damage per sheet, the degree of damage for each position stored in the storage means, and a threshold value predetermined for each type of print information. The image forming apparatus according to claim 1, wherein the number of printable sheets is calculated for each type, and the calculated number of printable sheets is displayed on a display unit.   The image forming apparatus according to claim 1, further comprising a transmission unit configured to transmit a degree of damage at each position stored in the storage unit to an external apparatus connected via a communication network. .   The image forming apparatus according to claim 4, further comprising a changing unit that changes the threshold value. Receiving means for receiving an instruction to change the threshold value transmitted from an external device connected via a communication network;
The image forming apparatus according to claim 12, wherein the changing unit changes the threshold based on a change instruction received by the receiving unit. The control means prints an image for confirming the image quality on paper,
An operation unit that receives an instruction to change the threshold value from a user who has confirmed an image printed on the paper;
The image forming apparatus according to claim 12, wherein the change unit changes the threshold based on a change instruction received by the operation unit. A fixing oscillating mechanism that oscillates the fixing device in a direction orthogonal to the paper conveyance direction;
The image forming apparatus according to claim 1, wherein the control unit calculates the degree of damage based on a position of the fixing device rocked by the fixing rocking mechanism. A sheet shift mechanism that shifts the position of the sheet relative to the fixing device in a direction orthogonal to the sheet conveyance direction;
The image forming apparatus according to claim 1, wherein the control unit calculates the damage degree based on a sheet position with respect to the fixing device shifted by the sheet shift mechanism. A polishing mechanism for polishing the surface of the fixing roller;
The image forming apparatus according to claim 1, wherein the control unit subtracts a predetermined value from the degree of damage when the surface of the fixing roller is polished by the polishing mechanism. The fixing device is replaceable,
The image forming apparatus according to claim 1, wherein the storage unit stores a degree of damage at each position for each fixing device. In a job management system comprising a plurality of image forming apparatuses and a server apparatus connected to the plurality of image forming apparatuses via a communication network so that data communication is possible.
Each of the plurality of image forming apparatuses is the image forming apparatus according to any one of claims 1 to 18,
The server device is
Server storage means for storing the position in the longitudinal direction of the fixing roller and the degree of damage in association with each other for each of the plurality of image forming apparatuses;
Based on the paper size corresponding to the job and the degree of damage at each position for each of the plurality of image forming apparatuses stored in the server storage unit, the job among the plurality of image forming apparatuses is determined. Selecting means for selecting an image forming apparatus to be executed;
A job management system comprising: In a job management system comprising a plurality of image forming apparatuses and a server apparatus connected to the plurality of image forming apparatuses via a communication network so that data communication is possible.
Each of the plurality of image forming apparatuses is the image forming apparatus according to any one of claims 1 to 18,
The server device is
Server storage means for storing the position in the longitudinal direction of the fixing roller and the degree of damage in association with each other for each of the plurality of image forming apparatuses;
Based on the print information corresponding to the job and the degree of damage at each position for each of the plurality of image forming apparatuses stored in the server storage unit, the job is executed among the plurality of image forming apparatuses. Selecting means for selecting an image forming apparatus to be
A job management system comprising:

Images